| 1. |
- Luo, Yifei, et al.
(författare)
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Technology Roadmap for Flexible Sensors
- 2023
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Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 17:6, s. 5211-5295
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Forskningsöversikt (refereegranskat)abstract
- Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.
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| 2. |
- Kristan, Matej, et al.
(författare)
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The first visual object tracking segmentation VOTS2023 challenge results
- 2023
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Ingår i: 2023 IEEE/CVF International conference on computer vision workshops (ICCVW). - : Institute of Electrical and Electronics Engineers Inc.. - 9798350307443 - 9798350307450 ; , s. 1788-1810
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking Segmentation VOTS2023 challenge is the eleventh annual tracker benchmarking activity of the VOT initiative. This challenge is the first to merge short-term and long-term as well as single-target and multiple-target tracking with segmentation masks as the only target location specification. A new dataset was created; the ground truth has been withheld to prevent overfitting. New performance measures and evaluation protocols have been created along with a new toolkit and an evaluation server. Results of the presented 47 trackers indicate that modern tracking frameworks are well-suited to deal with convergence of short-term and long-term tracking and that multiple and single target tracking can be considered a single problem. A leaderboard, with participating trackers details, the source code, the datasets, and the evaluation kit are publicly available at the challenge website1
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| 3. |
- Geng, Xiaojun, et al.
(författare)
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Contrasting phenology responses to climate warming across the northern extra-tropics
- 2022
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Ingår i: Fundamental Research. - : Elsevier BV. - 2667-3258. ; 2:5, s. 708-715
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Tidskriftsartikel (refereegranskat)abstract
- Climate warming has substantially advanced the timing of spring leaf-out of woody species at middle and high latitudes, albeit with large differences. Insights in the spatial variation of this climate warming response may therefore help to constrain future trends in leaf-out and its impact on energy, water and carbon balances at global scales. In this study, we used in situ phenology observations of 38 species from 2067 study sites, distributed across the northern hemisphere in China, Europe and the United States, to investigate the latitudinal patterns of spring leaf-out and its sensitivity (ST, advance of leaf-out dates per degree of warming) and correlation (RT, partial correlation coefficient) to temperature during the period 1980–2016. Across all species and sites, we found that ST decreased significantly by 0.15 ± 0.02 d °C−1 °N−1, and RT increased by 0.02 ± 0.001 °N−1 (both at P < 0.001). The latitudinal patterns in RT and ST were explained by the differences in requirements of chilling and thermal forcing that evolved to maximize tree fitness under local climate, particularly climate predictability and summed precipitation during the pre-leaf-out season. Our results thus showed complicated spatial differences in leaf-out responses to ongoing climate warming and indicated that spatial differences in the interactions among environmental cues need to be embedded into large-scale phenology models to improve the simulation accuracy.
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| 4. |
- Zhang, Kaicheng, et al.
(författare)
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SN 2014J in M82 : new insights on the spectral diversity of Type Ia supernovae
- 2018
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 481:1, s. 878-893
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Tidskriftsartikel (refereegranskat)abstract
- We present extensive spectroscopic observations for one of the closest Type Ia supernovae (SNe Ia), SN 2014J discovered in M82, ranging from 10.4 d before to 473.2 d after B-band maximum light. The diffuse interstellar band features detected in a high-resolution spectrum allow an estimate of line-of-sight extinction as A(v) similar to 1.9 +/- 0.6 mag. Spectroscopically, SN 2014J can be put into the high-velocity (HV) subgroup in Wang's classification with a velocity of Si II lambda 6355 at maximum light of upsilon(0) = 1.22 +/- 0.01 x 10(4) km s(-1) but has a low velocity gradient (LVG, following Benetti's classification) of (v) over bar = 41 +/- 2 km s(-1) d(-1), which is inconsistent with the trend that HV SNe Ia generally have larger velocity gradients. We find that the HV SNe Ia with LVGs tend to have relatively stronger Si III (at similar to 4400 angstrom) absorptions in early spectra, larger ratios of S II lambda 5468 to S II lambda 5640, and weaker Si II 5972 absorptions compared to their counterparts with similar velocities but high velocity gradients. This shows that the HV+ LVG subgroup of SNe Ia may have intrinsically higher photospheric temperature, which indicates that their progenitors may experience more complete burning in the explosions relative to the typical HV SNe Ia.
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| 5. |
- Chen, Shouzhi, et al.
(författare)
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Informing the SWAT model with remote sensing detected vegetation phenology for improved modeling of ecohydrological processes
- 2023
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Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694. ; 616
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Tidskriftsartikel (refereegranskat)abstract
- The Soil and Water Assessment Tool (SWAT) model has been widely applied for simulating the water cycle and quantifying the influence of climate change and anthropogenic activities on hydrological processes. A major uncertainty of SWAT stems from the poor representation of vegetation dynamics due to the use of a simplistic vegetation growth and development module. Using long-term remote sensing-based phenological data, the SWAT model's vegetation module was improved by adding a dynamic growth start date and the dynamic heat requirement for vegetation growth rather than using constant values. The new SWAT model was verified in the Han River basin, China, and found its performance was much improved in comparison with that of the original SWAT model. Specifically, the accuracy of the leaf area index (LAI) simulation improved notably (coefficient of determination (R2) increased by 0.193, Nash–Sutcliffe Efficiency (NSE) increased by 0.846, and percent bias decreased by 42.18 %), and that of runoff simulation improved modestly (R2 increased by 0.05 and NSE was similar). Additionally, it is found that the original SWAT model substantially underestimated evapotranspiration (Penman-Monteith method) in comparison with the new SWAT model (65.09 mm (or 22.17 %) for forests, 92.27 mm (or 32 %) for orchards, and 96.16 mm (or 36.4 %) for farmland), primarily due to the inaccurate representation of LAI dynamics. Our results suggest that an accurate representation of phenological dates in the vegetation growth module is important for improving the SWAT model performance in terms of estimating terrestrial water and energy balance.
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| 6. |
- Fu, Yongshuo H., et al.
(författare)
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Global warming is increasing the discrepancy between green (actual) and thermal (potential) seasons of temperate trees
- 2023
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 29:5, s. 1377-1389
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Tidskriftsartikel (refereegranskat)abstract
- Over the past decades, global warming has led to a lengthening of the time window during which temperatures remain favorable for carbon assimilation and tree growth, resulting in a lengthening of the green season. The extent to which forest green seasons have tracked the lengthening of this favorable period under climate warming, however, has not been quantified to date. Here, we used remote sensing data and long-term ground observations of leaf-out and coloration for six dominant species of European trees at 1773 sites, for a total of 6060 species–site combinations, during 1980–2016 and found that actual green season extensions (GS: 3.1 ± 0.1 day decade−1) lag four times behind extensions of the potential thermal season (TS: 12.6 ± 0.1 day decade−1). Similar but less pronounced differences were obtained using satellite-derived vegetation phenology observations, that is, a lengthening of 4.4 ± 0.13 and 7.5 ± 0.13 day decade−1 for GS and TS, respectively. This difference was mainly driven by the larger advance in the onset of the thermal season compared to the actual advance of leaf-out dates (spring mismatch: 7.2 ± 0.1 day decade−1), but to a less extent caused by a phenological mismatch between GS and TS in autumn (2.4 ± 0.1 day decade−1). Our results showed that forest trees do not linearly track the new thermal window extension, indicating more complex interactions between winter and spring temperatures and photoperiod and a justification of demonstrating that using more sophisticated models that include the influence of chilling and photoperiod is needed to accurately predict spring phenological changes under warmer climate. They urge caution if such mechanisms are omitted to predict, for example, how vegetative health and growth, species distribution and crop yields will change in the future.
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| 7. |
- Liu, Tao, et al.
(författare)
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16% efficiency all-polymer organic solar cells enabled by a finely tuned morphology via the design of ternary blend
- 2021
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Ingår i: Joule. - : CELL PRESS. - 2542-4351. ; 5:4, s. 914-930
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Tidskriftsartikel (refereegranskat)abstract
- A SUMMARY There is an urgent demand for all-polymer organic solar cells (AP-OSCs) to gain higher efficiency. Here, we successfully improve the performance to 16.09% by introducing a small amount of BN-T, a B <- N-type polymer acceptor, into the PM6:PY-IT blend. It has been found that BN-T makes the active layer, based on the PM6:PY-IT:BN-T ternary blend, more crystalline but meanwhile slightly reduces the phase separation, leading to enhancement of both exciton harvesting and charge transport. From a thermodynamic viewpoint, BN-T prefers to reside between PM6 and PY-IT, and the fraction of this fine-tunes the morphology. Besides, a significantly reduced nonradiative energy loss occurs in the ternary blend, along with the coexistence of energy and charge transfer between the two acceptors. The progressive performance facilitated by these improved properties demonstrates that AP-OSCs can possibly comparably efficient with those based on small molecule acceptors, further enhancing the competitiveness of this device type.
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| 8. |
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| 9. |
- Pan, Dong, et al.
(författare)
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Dimension Engineering of High-Quality InAs Nanostructures on a Wafer Scale
- 2019
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 19:3, s. 1632-1642
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Tidskriftsartikel (refereegranskat)abstract
- Low-dimensional narrow-band-gap III-V semiconductors are key building blocks for the next generation of high-performance nanoelectronics, nanophotonics, and quantum devices. Realizing these various applications requires an efficient methodology that enables the material dimensional control during the synthesis process and the mass production of these materials with perfect crystallinity, reproducibility, low cost, and outstanding electronic and optoelectronic properties. Although advances in one- and two-dimensional narrow-band-gap III-V semiconductors synthesis, the progress toward reliable methods that can satisfy all of these requirements has been limited. Here, we demonstrate an approach that provides a precise control of the dimension of InAs from one-dimensional nanowires to wafer-scale free-standing two-dimensional nanosheets, which have a high degree of crystallinity and outstanding electrical and optical properties, using molecular-beam epitaxy by controlling catalyst alloy segregation. In our approach, two-dimensional InAs nanosheets can be obtained directly from one-dimensional InAs nanowires by silver-indium alloy segregation, which is much easier than the previously reported methods, such as the traditional buffering technique and select-area epitaxial growth. Detailed transmission electron microscopy investigations provide solid evidence that the catalyst alloy segregation is the origination of the InAs dimensional transformation from one-dimensional nanowires to two-dimensional nanosheets and even to three-dimensional complex crosses. Using this method, we find that the wafer-scale free-standing InAs nanosheets can be grown on various substrates including Si, MgO, sapphire, GaAs, etc. The InAs nanosheets grown at high temperature are pure-phase single crystals and have a high electron mobility and a long time-resolved terahertz kinetics lifetime. Our work will open up a conceptually new and general technology route toward the effective controlling of the dimension of the low-dimensional III-V semiconductors. It may also enable the low-cost fabrication of free-standing nanosheet-based devices on an industrial scale.
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| 10. |
- Wen, Guanzhao, et al.
(författare)
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Excited-state properties of Y-series small molecule semiconductors
- 2021
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Ingår i: Dyes and Pigments. - : Elsevier BV. - 0143-7208. ; 192
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Tidskriftsartikel (refereegranskat)abstract
- The emergence of the Y series small molecule semiconductors, Y6 and its derivatives, have significantly improved the performance of polymer solar cells (PSCs). However, the excited-state properties of these Y-series small molecule semiconductors which are highly important for designing high-performance PSCs, need to be illustrated. In this work, the excited-state properties and electronic structures of the Y-series small molecules (Y5, Y6, Y10, N3, Y6-BO-4F, and Y6-BO-4Cl) have been systematically studied by using steady-state and time-resolved spectroscopies and quantum chemical calculations. It is shown that the influence of alkyl chains at the nitrogen atom of the pyrrole ring is weak for the electron affinities, ionization potentials, electron and hole reorganization energies and singlet exciton lifetime of Y molecules. Meanwhile, these parameters are found to be varied with the types of electron-deficient termini. Moreover, we find that Y10 and Y5 have the shortest singlet exciton lifetime in solution and the longest singlet exciton lifetime in film (~1100 ps), suggesting the engineering of electron-deficient termini can significantly influence the excited-state lifetime in solution and film. Our work could provide a guideline for designing Y-series acceptor materials for high-performance polymer solar cells.
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| 11. |
- Ye, Lian, et al.
(författare)
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Feasibility analysis of plastic and biomass hydrochar for blast furnace injection
- 2023
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 263
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Tidskriftsartikel (refereegranskat)abstract
- Hydrothermal carbonization (HTC) technology upgrades combustible waste (CW) to high-quality fuel known as hydrochar. However, there is a research gap regarding the application limit of hydrochar instead of fossil fuels in blast furnaces. In this study, the physical, chemical, and metallurgical properties of hydrochar were thoroughly analyzed. The results showed that gross calorific value, grindability, ignition temperature, explosivity, combustion and gasification all improved by HTC process compared with the waste feedstocks. Moreover, the HTC process can effectively remove harmful elements (K, Na, Cl, and S) from feedstocks into liquid and gas phase without adding other reagents, reducing harmful effects in the blast furnace. Removal rates by HTC were >80% for alkali metals and >73.9% for Cl (reaching 98.18% for polyvinyl chloride hydrochar). The environmental benefit calculation shows that the CO2 emission reduction of replacing bituminous coal with 40% HTC-treated maize straw can reach 94.7 kg/tHM. The annual CO2 reduction can reach 1.7 x 107 kg and the annual coal reduction is 1.5 x 107 kg of a blast furnace. The results showed that hydrochar is a clean energy source compared with fossil fuel alternatives and meets the blast furnace injection requirements.
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| 12. |
- Zhang, Nan, et al.
(författare)
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Physicochemical characteristics of three-phase products of low-rank coal by hydrothermal carbonization : experimental research and quantum chemical calculation
- 2022
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 261
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the distribution characteristics of gas, liquid, and solid products of low-rank coal by hydrothermal carbonization (HTC) at different temperatures are studied. Advanced testing methods are used to explore changing rules of physicochemical characteristics. Reaction properties of different regions are explained based on the mechanism of quantum chemistry. Experimental results showed that as the temperature increases, the volatile content decreases, the fixed carbon content increases, and impurities are removed in the form of gas or ions. The coal aliphatic properties are reduced, whereas the aromatization degree is significantly enhanced. Meanwhile, the specific surface area after upgrading is reduced, but the average pore diameter is increased, and the pore structure density is enhanced. The content of carbon-containing groups increases but that of carbon-oxygen groups decreases, which corresponds to the O/C ratio. Theoretical calculation results demonstrate that the more negative and positive areas of the surface electrostatic potential (ESP), the smaller distribution proportion. The ESP value in the vicinity of oxygen-containing group is relatively negative, indicating that it is more reactive, which is a good proof of the experiment's conclusions. In summary, low-rank coal obtained after HTC meets the blast furnace injection requirements and can be used for injection.
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| 13. |
- Zhang, Nan, et al.
(författare)
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Study of the comprehensive properties of low-rank coal using quantum chemical methods
- 2024
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Ingår i: Fuel. - : Elsevier. - 0016-2361 .- 1873-7153. ; 375
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we performed a comprehensive analysis of the molecular structural characteristics of low-rank coal and predicted its chemical properties. Using quantum chemistry and wave function analysis, we extensively discussed electrostatic potential surfaces, spectral characteristics, electronic structure, and orbital composition of coal. Our findings reveal that regions exhibiting negative electrostatic potential display increased reactivity during reactions. Oxygen-containing groups in coal molecules exhibit strong hydrophilicity upon interaction with water, primarily through medium-strength and weak hydrogen bonds. Hydrophobic sites are predominantly located near the aliphatic side chains and aromatic core groups of the coal molecules. Additionally, oxygen and carbon atom orbitals dominate regions of lower energy density, correlating with volatile substances that undergo initial decomposition during coal heating. These results provide fundamental insights into the physical and chemical properties of low-rank coal from a molecular perspective.
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| 14. |
- Zhang, Wei, et al.
(författare)
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Effect of post-thermal annealing on the performance and charge photogeneration dynamics of PffBT4T-2OD/PC71BM solar cells
- 2019
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Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we studied influence of post thermal annealing on the performance and charge photogeneration processes of PffBT4T-2OD/PC 71 BM solar cells. As-prepared device exhibits a high-power conversion efficiency of 9.5%, much higher than that after thermal annealing. To understand this phenomenon, we studied charge photogeneration processes in these solar cells by means of time resolved spectroscopy. We associate the degradation of solar cell performance with the reduction of exciton dissociation efficiency and with increased bimolecular recombination of photogenerated charges as a result of annealing. We correlate the generation of localized PffBT4T-2OD polarons observed via spectro-electrochemical measurements with enhancement of the bimolecular charge recombination of annealed solar cells.
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| 15. |
- Zhao, Ningjiu, et al.
(författare)
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Photoinduced Polaron Formation in a Polymerized Electron-Acceptor Semiconductor
- 2022
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Ingår i: The Journal of Physical Chemistry Letters. - : AMER CHEMICAL SOC. - 1948-7185. ; 13:23, s. 5143-5150
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Tidskriftsartikel (refereegranskat)abstract
- Polymerized small molecular acceptor (PSMA) based all-polymer solar cells (all-PSC) have achieved power conversion efficiencies (PCE) over 16%, and the PSMA is considered to hold great promise for further improving the performance of all-PSC. Yet, in comparison with that of the polymer donor, the photophysics of a polymerized acceptor remains poorly understood. Herein, the excited state dynamics in a polymerized acceptor PZT810 was comprehensively investigated under various pump intensities and photon energies. The excess excitation energy was found to play a key role in excitons dissociation into free polarons for neat PSMA films, while free polarons cannot be generated from the polaron pairs in neat acceptor films. This work reveals an in-depth understanding of relaxation dynamics for PSMAs and that the underlying photophysical origin of PSMA can be mediated by excitation energies and intensities. These results would benefit the realization of the working mechanism for all-PSC and the designing of new PSMAs.
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| 16. |
- An, Hongbin, et al.
(författare)
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Microfluidic contact lenses for unpowered, continuous and non-invasive intraocular pressure monitoring
- 2019
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Ingår i: Sensors and Actuators A-Physical. - : Elsevier BV. - 0924-4247 .- 1873-3069. ; 295, s. 177-187
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Tidskriftsartikel (refereegranskat)abstract
- Intraocular pressure (IOP) is a crucial physiological indicator of the visual system and play a key role in the diagnosis and treatment of glaucoma. However, the current handheld single measurement tools for IOP sensing cannot meet the future demands for glaucoma management. Thus, here we present the microfluidic contact lens sensors that could provide unpowered, continuous and non-invasive IOP monitoring. The microfluidic contact lens is comprised of a sensing layer of the micropatterned soft-elastomer and a hard plastic reference layer. The devices use the annular sensing chamber filled with the dyed liquid and a sensing microchannel as the IOP transducer. Resulting from the volume variance of the sensing chamber and caused by the deformation of the sensing layer under pressure, the IOP signal is detected as the displacement change of the dyed liquid's interface in the sensing channel, and in which, the displacement change can be optically observed by using the smart-phone camera. Based on the silicone rubber model eyeball, the sensing mechanism of the devices with different design parameters (the position of the sensing chambers and the dimension of the sensing channels) are explored by using the theoretical analyses and experimental investigations. The characteristics of these microfluidic contact lens sensors are tested, in which, the maximum sensitivity of the device (with the sensing chamber of 8.5 mm in diameter and the sensing channel of 100 x 40 um in size) can be achieved to 0.708 mm/mmHg in a working range of 0 (4) over tilde0 mmHg. Also, cyclical tests were conducted and indicated that the devices had a good reversibility and Long-term stability. Furthermore, the device (with the sensing chamber of 5.0 mm in diameter and the sensing channel of 150 x 40 urn in size) was test on the porcine eyes ex vivo, showing a sensitivity of 0.2832 mm/mmHg in a range of 8 (3) over tilde2 mmHg and, the device had a good reproducibility to its IOP change. This work provides a promising approach for unpowered, continuous and non-invasive monitoring of IOP.
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| 17. |
- Azevedo, Flavio, et al.
(författare)
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Social and moral psychology of COVID-19 across 69 countries
- 2023
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Ingår i: Scientific Data. - : NATURE PORTFOLIO. - 2052-4463. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- The COVID-19 pandemic has affected all domains of human life, including the economic and social fabric of societies. One of the central strategies for managing public health throughout the pandemic has been through persuasive messaging and collective behaviour change. To help scholars better understand the social and moral psychology behind public health behaviour, we present a dataset comprising of 51,404 individuals from 69 countries. This dataset was collected for the International Collaboration on Social & Moral Psychology of COVID-19 project (ICSMP COVID-19). This social science survey invited participants around the world to complete a series of moral and psychological measures and public health attitudes about COVID-19 during an early phase of the COVID-19 pandemic (between April and June 2020). The survey included seven broad categories of questions: COVID-19 beliefs and compliance behaviours; identity and social attitudes; ideology; health and well-being; moral beliefs and motivation; personality traits; and demographic variables. We report both raw and cleaned data, along with all survey materials, data visualisations, and psychometric evaluations of key variables.
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| 18. |
- Chai, Yifan, et al.
(författare)
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Study on strength and reduction characteristics of iron ore powder-green carbon composite briquettes
- 2024
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Ingår i: Fuel. - : Elsevier Ltd. - 0016-2361 .- 1873-7153. ; 377
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Tidskriftsartikel (refereegranskat)abstract
- The metallurgical industry is a key sector for carbon emissions, and in recent years, there has been widespread attention on the use of biomass resources as a green, renewable, and carbon–neutral energy source material for low carbon ironmaking processes. The waste wood after hydrothermal-pyrolysis carbonization has the characteristics of low content of harmful elements and high content of fixed carbon. In this study, the waste wood after hydrothermal-pyrolysis two-step carbonization treatment was used as a reducing agent for the reduction of iron ore to prepare iron ore powder- green carbon composite briquettes (ICCB) with two carbon–oxygen ratios. The study investigated the effects of reduction behavior and reaction temperature on the reduction performance of the ICCB. The results indicate that with the increase in reaction temperature, the volume of the ICCB gradually contracts, leading to a reduction in mass. The shrinkage rate of the ICCB during self-reduction at 1200℃ is significantly higher than during co-reduction, and the shrinkage effect of the C/O 0.5 ICCB is more pronounced than that of the C/O 0.8 ICCB. Due to the excessive carbon content in the C/O 0.8 ICCB, the carbon cannot be fully consumed during the reaction process, resulting in consistently low compressive strength of the ICCB, with a compressive strength of 12 N after reduction at 1200℃. In contrast, the iron phase in the C/O 0.5 ICCB gradually recrystallizes during the reduction process, ultimately yielding plastic iron briquettes with compressive strengths exceeding 3000 N after different reaction behaviors at 1200℃. In summary, reducing the carbon-to-oxygen ratio and increasing the reaction temperature contribute to the volume contraction and enhanced compressive strength of the ICCB during the reduction process.
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| 19. |
- Chen, Shouzhi, et al.
(författare)
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Influences of Shifted Vegetation Phenology on Runoff Across a Hydroclimatic Gradient
- 2022
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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Climate warming has changed vegetation phenology, and the phenology-associated impacts on terrestrial water fluxes remain largely unquantified. The impacts are linked to plant adjustments and responses to climate change and can be different in different hydroclimatic regions. Based on remote sensing data and observed river runoff of hydrological station from six river basins across a hydroclimatic gradient from northeast to southwest in China, the relative contributions of the vegetation (including spring and autumn phenology, growing season length (GSL), and gross primary productivity) and climatic factors affecting the river runoffs over 1982–2015 were investigated by applying gray relational analysis (GRA). We found that the average GSLs in humid regions (190–241 days) were longer than that in semi-humid regions (186–192 days), and the average GSLs were consistently extended by 4.8–13.9 days in 1982–2015 period in six river basins. The extensions were mainly linked to the delayed autumn phenology in the humid regions and to advanced spring phenology in the semi-humid regions. Across all river basins, the GRA results showed that precipitation (r = 0.74) and soil moisture (r = 0.73) determine the river runoffs, and the vegetation factors (VFs) especially the vegetation phenology also affected the river runoffs (spring phenology: r = 0.66; GSL: r = 0.61; autumn phenology: r = 0.59), even larger than the contribution from temperature (r = 0.57), but its relative importance is climatic region-dependent. Interestingly, the spring phenology is the main VF in the humid region for runoffs reduction, while both spring and autumn growth phenology are the main VFs in the semi-humid region, because large autumn phenology delay and less water supply capacity in spring amplify the effect of advanced spring phenology. This article reveals diverse linkages between climatic and VFs, and runoff in different hydroclimatic regions, and provides insights that vegetation phenology influences the ecohydrology process largely depending on the local hydroclimatic conditions, which improve our understanding of terrestrial hydrological responses to climate change.
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| 20. |
- Chen, Yani, et al.
(författare)
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Tailoring Organic Cation of 2D Air-Stable Organometal Halide Perovskites for Highly Efficient Planar Solar Cells
- 2017
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Ingår i: Advanced Energy Materials. - : Wiley. - 1614-6832. ; 7:18
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Tidskriftsartikel (refereegranskat)abstract
- 2D perovskites have recently been shown to exhibit significantly improved environmental stability. Derived from their 3D analogues, 2D perovskites are formed by inserting bulky alkylammonium cations in-between the anionic layers. However, these insulating organic spacer cations also hinder charge transport. Herein, such a 2D perovskite, (iso-BA)2(MA)3Pb4I13, that contains short branched-chain spacer cations (iso-BA+) and shows a remarkable increase of optical absorption and crystallinity in comparison to the conventional linear one, n-BA+, is designed. After applying the hot-casting (HC) technique, all these properties are further improved. The HC (iso-BA)2(MA)3Pb4I13 sample exhibits the best ambient stability by maintaining its initial optical absorption after storage of 840 h in an environmental chamber at 20 °C with a relative humidity of 60% without encapsulation. More importantly, the out-of-plane crystal orientation of (iso-BA)2(MA)3Pb4I13 film is notably enhanced, which increases cross-plane charge mobility. As a result, the highest power conversion efficiencies (PCEs) measured from for current density versus voltage curves afford 8.82% and 10.63% for room-temperature and HC-processed 2D perovskites based planar solar cells, respectively. However, the corresponding steady-state PCEs are remarkably lower, which is presumably due to the significant hysteresis phenomena caused by low charge extraction efficiency at interfaces of C60/2D perovskites.
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| 21. |
- Ding, Li, et al.
(författare)
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Somatic mutations affect key pathways in lung adenocarcinoma
- 2008
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 455:7216, s. 1069-1075
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Tidskriftsartikel (refereegranskat)abstract
- Determining the genetic basis of cancer requires comprehensive analyses of large collections of histopathologically well-classified primary tumours. Here we report the results of a collaborative study to discover somatic mutations in 188 human lung adenocarcinomas. DNA sequencing of 623 genes with known or potential relationships to cancer revealed more than 1,000 somatic mutations across the samples. Our analysis identified 26 genes that are mutated at significantly high frequencies and thus are probably involved in carcinogenesis. The frequently mutated genes include tyrosine kinases, among them the EGFR homologue ERBB4; multiple ephrin receptor genes, notably EPHA3; vascular endothelial growth factor receptor KDR; and NTRK genes. These data provide evidence of somatic mutations in primary lung adenocarcinoma for several tumour suppressor genes involved in other cancers--including NF1, APC, RB1 and ATM--and for sequence changes in PTPRD as well as the frequently deleted gene LRP1B. The observed mutational profiles correlate with clinical features, smoking status and DNA repair defects. These results are reinforced by data integration including single nucleotide polymorphism array and gene expression array. Our findings shed further light on several important signalling pathways involved in lung adenocarcinoma, and suggest new molecular targets for treatment.
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| 22. |
- Geng, Wenping, et al.
(författare)
-
Giant negative electrocaloric effect in antiferroelectric La-modified PbZrO3 thin films within wide temperature range
- 2021
-
Ingår i: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 886
-
Tidskriftsartikel (refereegranskat)abstract
- Antiferroelectric thin films have exhibited outstanding negative electrocaloric effect (ECE), which are potential candidate regarding to the solid-state refrigeration technology. In this work, Pb0.97La0.02ZrO3 (PLZ) antiferroelectric thin films were prepared on LaNiO3(LNO)/Pt electrode and LNO electrode by sol-gel method. Giant negative electrocaloric effect (ΔT ~ −13.2 K) can observed in wide temperature range (213–493 K) that deposited on composite electrode, which can be attributed to better electric conductivity of LNO/Pt composite electrode than LNO electrode. In addition to outstanding negative ECE, positive ECE also can be obtained near curie temperature, which is caused by phase transition from ferroelectric (FE) to paraelectric (PE) state. The optimized ECE property contributed to the phase transition and introduction of composite electrode, which pave the giant prospect considering high-efficiency solid-state refrigeration devices through combination of positive and negative ECE.
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| 23. |
- He, Lei, et al.
(författare)
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Non-symmetric responses of leaf onset date to natural warming and cooling in northern ecosystems
- 2023
-
Ingår i: PNAS Nexus. - 2752-6542. ; 2:9
-
Tidskriftsartikel (refereegranskat)abstract
- The northern hemisphere has experienced regional cooling, especially during the global warming hiatus (1998-2012) due to ocean energy redistribution. However, the lack of studies about the natural cooling effects hampers our understanding of vegetation responses to climate change. Using 15,125 ground phenological time series at 3,620 sites since the 1950s and 31-year satellite greenness observations (1982-2012) covering the warming hiatus period, we show a stronger response of leaf onset date (LOD) to natural cooling than to warming, i.e. the delay of LOD caused by 1°C cooling is larger than the advance of LOD with 1°C warming. This might be because cooling leads to larger chilling accumulation and heating requirements for leaf onset, but this non-symmetric LOD response is partially offset by warming-related drying. Moreover, spring greening magnitude, in terms of satellite-based greenness and productivity, is more sensitive to LOD changes in the warming area than in the cooling. These results highlight the importance of considering non-symmetric responses of spring greening to warming and cooling when predicting vegetation-climate feedbacks.
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| 24. |
- Huang, Yaqi, et al.
(författare)
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Application of the International Classification of Functioning, Disability and Health (ICF) in dementia research and practice : A scoping review
- 2023
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Ingår i: Aging & Mental Health. - : Taylor & Francis. - 1360-7863 .- 1364-6915. ; 27:2, s. 357-371
-
Forskningsöversikt (refereegranskat)abstract
- OBJECTIVES: The International Classification of Functioning, Disability and Health (ICF) endorsed by the World Health Organization provides a conceptual framework for describing functioning and disability based on a biopsychosocial model. Although dementia is one of the leading causes of disability, yet little is known on the extent to how the ICF has been utilized in dementia research and practice. The study aimed to examine and map the current applications of the ICF with dementia from a body of earlier studies and to explore the potential use in person-centred dementia care.METHODS: The Arksey and O'Malley framework was used to guide the searching, selecting, and synthesizing process. The scoping review was reported following The Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Review (PRISMA-ScR) guidelines.RESULTS: A total of 34 studies were included. The applications of ICF were classified into 4 themes: (1) in clinical practice and the education of health professionals (n = 20); (2) community support services and income support (n = 3); (3) population-based, census, or survey data (n = 10); (4) advocacy and empowerment purposes (n = 1).CONCLUSION: The ICF has made a major impact on dementia in clinical settings. Findings strongly support applying the ICF to person-centered dementia care. In the future, more empirical studies are needed to expand the scope of ICF use in dementia research and practice.
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| 25. |
- Jiang, Heng, et al.
(författare)
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Measuring and preventing alcohol use and related harm among young people in Asian countries : a thematic review
- 2018
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Ingår i: Global Health Research and Policy. - : Springer Science and Business Media LLC. - 2397-0642. ; 3:14
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Tidskriftsartikel (refereegranskat)abstract
- Background: The paper reviews alcohol consumption patterns and alcohol-related social and health issues among 15-29-year old young people in Asian countries, and discusses strategies for preventing and controlling alcohol use and related harms.Methods: We searched Google Scholar, PubMed, and Web of Science for reports, reviews and journal articles published in English between 1st Jan 1990 and 31st August 2016.Results: Forty-one reports, reviews and journal papers were identified and included in the final review. The current drinking levels and prevalence among young people are markedly different between eight included Asian countries, ranging from 4.2% in Malaysia to 49.3% in China. In a majority of the selected Asian countries, over 15% of total deaths among young men and 6% among young women aged 15-29 years are attributable to alcohol use. Alcohol use among young people is associated with a number of harms, including stress, family violence, injuries, suicide, and sexual and other risky behaviours. Alcohol policies, such as controlling sales, social supply and marketing, setting up/raising a legal drinking age, adding health warning labels on alcohol containers, and developing a surveillance system to monitor drinking pattern and risky drinking behaviour, could be potential means to reduce harmful use of alcohol and related harm among young people in Asia.Conclusions: The review reveals that drinking patterns and behaviours vary across eight selected Asian countries due to culture, policies and regional variations. The research evidence holds substantial policy implications for harm reduction on alcohol drinking among young people in Asian countries -- especially for China, which has almost no alcohol control policies at present.
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| 26. |
- Li, Xinxi, et al.
(författare)
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Increasing importance of precipitation in spring phenology with decreasing latitudes in subtropical forest area in China
- 2021
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Ingår i: Agricultural and Forest Meteorology. - : Elsevier BV. - 0168-1923. ; 304-305
-
Tidskriftsartikel (refereegranskat)abstract
- Climate warming has significantly advanced plant spring phenology in temperate and boreal biomes in the northern hemisphere. However, the response of subtropical forest phenology to climate change remains largely unclear. This study aimed to determine the spatiotemporal patterns of spring photosynthetic phenology in subtropical forests in China over the period 2002-2017 and explore its underlying mechanism in response to the changes of different climate variables. We applied four methods to extract the start of the photosynthetic period (SOP) from a solar–induced chlorophyll fluorescence (SIF) data set during the period 2002 to 2017, and determined correlations between SOP and environmental factors using partial correlation analyses. Overall, the SOP was advanced by 6.8 days. Furthermore, we found that the SIF-based SOP is highly correlated with the flux data–based photosynthetic onset dates, demonstrating that SIF can be a useful index in characterizing the photosynthetic phenology in subtropical forests. Interestingly, based on partial correlation analysation temperature dominated the SOP in the northern subtropical forest, but the importance of precipitation increased with decreasing latitudes, and the primary climatic control of SOP in southern monsoon evergreen forests is precipitation. These results suggested that the predicted increase in temperature and shift in precipitation regimes under ongoing climate change might potentially largely affect the photosynthetic phenology, and thus affect the carbon and water cycles in subtropical forests.
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| 27. |
- Li, Xinlei, et al.
(författare)
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Shaped by uneven Pleistocene climate: mitochondrial phylogeographic pattern and population history of White Wagtail Motacilla alba (Aves: Passeriformes).
- 2016
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Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857 .- 1600-048X. ; 47, s. 263-274
-
Tidskriftsartikel (refereegranskat)abstract
- We studied the phylogeography and population history of the white wagtail Motacilla alba, which has a vast breeding range, covering areas with different Pleistocene climatic histories. The mitochondrial NADH dehydrogenase subunit II gene (ND2) and Control Region (CR) were analyzed for 273 individuals from 45 localities. Our data comprised all nine subspecies of white wagtail. Four primary clades were inferred (M, N, SW and SE), with indications of M. grandis being nested within M. alba. The oldest split was between two haplotypes from the endemic Moroccan M. a. subpersonata (clade M) and the others, at 0.63–0.96 Mya; other divergences were at 0.31–0.38 Mya. The entire differentiation falls within the part of the Pleistocene characterized by Milankovitch cycles of large amplitudes and durations. Clade N was distributed across the northern Palearctic; clade SW in southwestern Asia plus the British Isles and was predicted by Ecological niche models (ENMs) to occur also in central and south Europe; and clade SE was distributed in central and east Asia. e deep divergence within M. a. subpersonata may reflect retention of ancestral haplotypes. Regional differences in historical climates have had different impacts on different populations: clade N expanded after the last glacial maximum (LGM), whereas milder Pleistocene climate of east Asia allowed clade SE a longer expansion time (since MIS 5); clade SW expanded over a similarly long time as clade SE, which is untypical for European species. ENMs supported these conclusions in that the northern part of the Eurasian continent was unsuitable during the LGM, whereas southern parts remained suitable. e recent divergences and poor structure in the mitochondrial tree contrasts strongly with the pronounced, well defined phenotypical differentiation, indicating extremely fast plumage divergence.
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| 28. |
- Liang, Wang, et al.
(författare)
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Life cycle assessment of blast furnace ironmaking processes : A comparison of fossil fuels and biomass hydrochar applications
- 2023
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 345
-
Tidskriftsartikel (refereegranskat)abstract
- The impact of the iron and steel production process on the ecological environment cannot be ignored. This study aims to assess the impact of life cycle assessment on the traditional fossil fuel blast furnace ironmaking process and the biomass hydrochar blast furnace ironmaking process. The Simapro v9.0 software is used to comprehensively evaluate the life cycle impacts of biomass hydrochar in the blast furnace ironmaking process. The results show that the life cycle impact categories of the blast furnace ironmaking process mainly include global warming, non-renewable energy and respiratory inorganics. The global warming impact of the ironmaking process using hydrochar is 2054.00 kg CO2 eq, which is 420.61 kg CO2 eq less than that of traditional blast furnace ironmaking process. The global warming impact is mainly reflected in the emission of CO2 gas, and the main source is the generation of blast furnace gas and the use of sinter. The respiratory inorganics impact is mainly manifested in the emission of nitrogen oxides, sulfur oxides and particulates, which mainly comes from the mining of iron ore and the production of sinter. The non-renewable energy impact mainly comes from the coal resources, and the use of other renewable energy such as biomass energy is an important way to reduce the impact. Therefore, biomass hydrochar used in the metallurgical process is more suitable for sustainable devel-opment of the ecological environment.
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| 29. |
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| 30. |
- Shen, Zhaoyan, et al.
(författare)
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A Multiagent Reinforcement Learning-Assisted Cache Cleaning Scheme for DM-SMR
- 2023
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Ingår i: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0278-0070 .- 1937-4151. ; 42:8, s. 2500-2513
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Tidskriftsartikel (refereegranskat)abstract
- To support nonsequential writes, persistent cache (PC) is constructed in drive managed SMR (DM-SMR) drive. However, PC cleaning introduces drastic performance degradation and enlarges tail latencies. In this article, we propose to utilize reinforcement learning (RL) to mitigate the longtail latency of PC cleaning. Our scheme uses the lightweight Q-learning method to monitor and learn the idle time of I/O workloads, based on which PC cleaning is intelligently guided, thus maximally exploit idle time between requests and hiding tail latency from normal requests. In addition, a multiagent RL scheme with clustering algorithm is adopted to further mitigate the tail latencies and adapt to variable workloads. We emulate a DM-SMR drive inside a Linux device driver to implement our proposed scheme. According to the experimental results, our scheme can effectively reduce the tail latency by 59.45% at the 99.9th percentile and the average latency by 48.75% compared with a typical shingled magnetic recording (SMR) design.
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| 31. |
- Su, Xiaojun, et al.
(författare)
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Effect of hydrogen chloride etching on carrier recombination processes of indium phosphide nanowires
- 2019
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 11:40, s. 18550-18558
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction of in situ HCl etching to an epitaxial growth process has been shown to suppress radial growth and improve the morphology and optical properties of nanowires. In this paper, we investigate the dynamics of photo-generated charge carriers in a series of indium phosphide nanowires grown with varied HCl fluxes. Time resolved photo-induced luminescence, transient absorption and time resolved terahertz spectroscopy were employed to investigate charge trapping and recombination processes in the nanowires. Since the excitation photons generate charges predominantly in less than a half length of the nanowires, we can selectively assess the charge carrier dynamics at their top and bottom. We found that the photoluminescence decay is dominated by the decay of the mobile hole population due to trapping, which is affected by the HCl etching. The hole trapping rate is in general faster at the top of the nanowires than at the bottom. In contrast, electrons remain highly mobile until they recombine non-radiatively with the trapped holes. The slowest hole trapping as well as the least efficient non-radiative recombination was recorded for etching using the HCl molar fraction of χHCl = 5.4 × 10-5
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| 32. |
- Su, Xiaojun, et al.
(författare)
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Understanding of photophysical processes in dio additive-treated ptb7:Pc71 bm solar cells
- 2021
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Ingår i: Crystals. - : MDPI AG. - 2073-4352. ; 11:9
-
Tidskriftsartikel (refereegranskat)abstract
- 1,8-diiodooctane (DIO) additive is an important method for optimizing the morphology and device performance of polythieno[3,4-b]-thiophene-co-benzodithiophene (PTB7)-based polymer solar cells. However, the effect of DIO additive on charge photogeneration dynamics of PTB7-based polymer solar cells is still poorly understood. In this work, the effect of DIO additive on the carrier photogeneration dynamics, as well as device performance of PTB7: [6,6]-phenyl-C71-butyric acid methyl ester (PC71 BM) solar cells was studied. Bias-dependent photoluminescence (PL) experiments of a neat PTB7 device show that the exciton cannot be dissociated by the electric field in the device within the operating voltage range, but it can be effectively dissociated by the high electric field. PL and time-resolved PL studies show that DIO additive reduces the phase size of PTB7 in the blend film, resulting in an increased exciton dissociation efficiency. The carrier recombination processes were studied by transient absorption, which shows geminate carrier recombination was suppressed in the DIO-treated PTB7:PC71 BM device in ultrafast time scale. The increased exciton dissociation efficiency and suppressed carrier recombination in ultrafast time scale play an important role for DIO-treated PTB7:PC71 BM solar cells to attain a higher power conversion efficiency.
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| 33. |
- Sun, Jiaqi, et al.
(författare)
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Water-Energy-Food integrated management model under Uncertainty-A case study of Yulin City
- 2023
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Ingår i: Journal of Hydrology. - 0022-1694 .- 1879-2707. ; 625
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Tidskriftsartikel (refereegranskat)abstract
- Water, energy, and food are indispensable human survival and development resources. With the rapid development of the social economy, the systematic risk of water, energy, and food is becoming increasingly prominent. Water, energy, and food security are threatened to varying degrees. At the same time, water, energy, and food are interrelated, restricted, and interdependent. It is of great scientific significance to reveal and optimize the WEF (Water-Energy-Food) nexus. This study relied on Chance constrained programming and Fuzzy credibility constrained programming to deal with randomness and fuzziness in the WEF nexus. Meanwhile, based on Bi-level programming, aiming at minimizing water allocation and maximizing system benefits, a Water-Energy-Food Integrated Management Model to deal with multiple Uncertainties, called IMMU-WEF model was constructed. The model solved the critical effects of the randomness of water supply and the subjective fuzziness of water demand on water resources allocation, power generation, primary energy extraction, and food planting area. The results showed that the IMMU-WEF model could efficiently deal with the game between different departments in the resource management system, the random uncertainty expressed by probability density, and the fuzzy uncertainty caused by subjective factors. It can develop a stable management scheme for resource management. Applying the mode to Yulin City, China, it is found that water supply and demand fluctuation dramatically impacts on the WEF system benefit, water resources allocation, energy and food production. Specifically, the system benefit will increase over time, with a total benefit of 1974.04 × 108-1998.06 × 108 yuan (2021–2025), 3065.69 × 108-3100.50 × 108 yuan (2026–2030), and 4128.80 × 108-4191.07 × 108 yuan (2031–2035). Additionally, the system water allocation, primary energy extraction, power generation, and food planting are expected to increase over three time periods. With the increase of water supply in the future, the energy and food production in Yulin City show an increasing trend. It indicates that water shortage will continue to be a major problem in Yulin in the three periods, and that the city still needs to increase water supply and diversion projects to ensure energy security and food security. The results can provide an optimal management scheme for ensuring Yulin City’s water, energy, and food security.
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| 34. |
- Van Bavel, Jay J., et al.
(författare)
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National identity predicts public health support during a global pandemic
- 2022
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Ingår i: Nature Communications. - : Nature Portfolio. - 2041-1723. ; 13:1
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding collective behaviour is an important aspect of managing the pandemic response. Here the authors show in a large global study that participants that reported identifying more strongly with their nation reported greater engagement in public health behaviours and support for public health policies in the context of the pandemic. Changing collective behaviour and supporting non-pharmaceutical interventions is an important component in mitigating virus transmission during a pandemic. In a large international collaboration (Study 1, N = 49,968 across 67 countries), we investigated self-reported factors associated with public health behaviours (e.g., spatial distancing and stricter hygiene) and endorsed public policy interventions (e.g., closing bars and restaurants) during the early stage of the COVID-19 pandemic (April-May 2020). Respondents who reported identifying more strongly with their nation consistently reported greater engagement in public health behaviours and support for public health policies. Results were similar for representative and non-representative national samples. Study 2 (N = 42 countries) conceptually replicated the central finding using aggregate indices of national identity (obtained using the World Values Survey) and a measure of actual behaviour change during the pandemic (obtained from Google mobility reports). Higher levels of national identification prior to the pandemic predicted lower mobility during the early stage of the pandemic (r = -0.40). We discuss the potential implications of links between national identity, leadership, and public health for managing COVID-19 and future pandemics.
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| 35. |
- Wu, Cary, et al.
(författare)
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Chinese Citizen Satisfaction with Government Performance during COVID-19
- 2021
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Ingår i: Journal of Contemporary China. - : Informa UK Limited. - 1067-0564 .- 1469-9400. ; 30:132, s. 930-944
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Tidskriftsartikel (refereegranskat)abstract
- While foreign pundits have alternatively blamed and praised the Chinese government’s handling of the COVID-19 virus, little is known about how citizens within China understand this performance. This article considers how satisfied Chinese citizens are with their government’s performance during the COVID-19 pandemic. It first considers the impact of authoritarian control, political culture, and/or actual government performance on citizen satisfaction. Then, it tests the consequences of satisfaction and specifically whether citizen satisfaction leads to greater trust. Analyzing data from the first post-COVID survey of its kind (n = 19,816) conducted from April 22 to 28 April 2020, the authors find that Chinese citizens have an overall high level of satisfaction, but that this satisfaction drops with each lower level of government. Further, authoritarian control, political culture, and awareness of government performance all contribute to citizen satisfaction and this in turn, has enhanced public support for the Chinese government.
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| 36. |
- Xu, Jiangchang, et al.
(författare)
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Automatic segmentation of orbital wall from CT images via a thin wall region supervision-based multi-scale feature search network
- 2023
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Ingår i: International Journal of Computer Assisted Radiology and Surgery. - : Springer Nature. - 1861-6410 .- 1861-6429. ; 18:11, s. 2051-2062
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Orbital wall segmentation is critical for orbital measurement and reconstruction. However, the orbital floor and medial wall are made up of thin walls (TW) with low gradient values, making it difficult to segment the blurred areas of the CT images. Clinically, doctors have to manually repair the missing parts of TW, which is time-consuming and laborious. Methods: To address these issues, this paper proposes an automatic orbital wall segmentation method based on TW region supervision using a multi-scale feature search network. First of all, in the encoding branch, the densely connected atrous spatial pyramid pooling based on the residual connection is adopted to achieve a multi-scale feature search. Then, for feature enhancement, multi-scale up-sampling and residual connection are applied to perform skip connection of features in multi-scale convolution. Finally, we explore a strategy for improving the loss function based on the TW region supervision, which effectively increases the TW region segmentation accuracy. Results: The test results show that the proposed network performs well in terms of automatic segmentation. For the whole orbital wall region, the Dice coefficient (Dice) of segmentation accuracy reaches 96.086 ± 1.049%, the Intersection over Union (IOU) reaches 92.486 ± 1.924%, and the 95% Hausdorff distance (HD) reaches 0.509 ± 0.166 mm. For the TW region, the Dice reaches 91.470 ± 1.739%, the IOU reaches 84.327 ± 2.938%, and the 95% HD reaches 0.481 ± 0.082 mm. Compared with other segmentation networks, the proposed network improves the segmentation accuracy while filling the missing parts in the TW region. Conclusion: In the proposed network, the average segmentation time of each orbital wall is only 4.05 s, obviously improving the segmentation efficiency of doctors. In the future, it may have a practical significance in clinical applications such as preoperative planning for orbital reconstruction, orbital modeling, orbital implant design, and so on.
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| 37. |
- Zeng, Xulu, et al.
(författare)
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In situ passivation of GaxIn(1−x)P nanowires using radial AlyIn(1−y)P shells grown by MOVPE
- 2021
-
Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 32:42
-
Tidskriftsartikel (refereegranskat)abstract
- GaxIn(1−x)P nanowires with suitable bandgap (1.35-2.26 eV) ranging from the visible to near-infrared wavelength have great potential in optoelectronic applications. Due to the large surface-to-volume ratio of nanowires, the surface states become a pronounced factor affecting device performance. In this work, we performed a systematic study of GaxIn(1−x)P nanowires' surface passivation, utilizing AlyIn(1−y)P shells grown in situ by using a metal-organic vapor phase epitaxy system. Time-resolved photoinduced luminescence and time-resolved THz spectroscopy measurements were performed to study the nanowires' carrier recombination processes. Compared to the bare Ga0.41In0.59P nanowires without shells, the hole and electron lifetime of the nanowires with the Al0.36In0.64P shells are found to be larger by 40 and 1.1 times, respectively, demonstrating effective surface passivation of trap states. When shells with higher Al composition were grown, both lifetimes of free holes and electrons decreased prominently. We attribute the acceleration of PL decay to an increase in the trap states' density due to the formation of defects, including the polycrystalline and oxidized amorphous areas in these samples. Furthermore, in a separate set of samples, we varied the shell thickness. We observed that a certain shell thickness of approximately ∼20 nm is needed for efficient passivation of Ga0.31In0.69P nanowires. The photoconductivity of the sample with a shell thickness of 23 nm decays 10 times slower compared with that of the bare core nanowires. We concluded that both the hole and electron trapping and the overall charge recombination in GaxIn(1−x)P nanowires can be substantially passivated through growing an AlyIn(1−y)P shell with appropriate Al composition and thickness. Therefore, we have developed an effective in situ surface passivation of GaxIn(1−x)P nanowires by use of AlyIn(1−y)P shells, paving the way to high-performance GaxIn(1−x)P nanowires optoelectronic devices.
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| 38. |
- Zhang, Chaofan, et al.
(författare)
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Alloying and oxidation of in situ produced core-shell Al@Yb nanoalloy particles-An "on-the-fly" study.
- 2014
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 141:8
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Tidskriftsartikel (refereegranskat)abstract
- Core-shell-structured nanoalloy particles with an Al-dominated interior covered by few Yb monolayers have been fabricated using a vapor-aggregation method involving magnetron sputtering. The radially segregated structure of the Yb-Al nanoparticles has been disclosed by "on-the-fly" photoelectron spectroscopy monitoring of the nanoparticle beam in Yb 4f and Al 2p electron binding energy regions. Both, the binding energy values and the electron microscopy images taken on the deposited nanoparticles, allow estimating their dimensions to be in the 5-10 nm range. The photoelectron spectroscopy results suggest that in these nanoparticles no trivalent Yb - the typical case for the macroscopic Yb-Al alloy - is present. The oxidation of preformed Yb-Al nanoparticles was successfully attempted, leading to the appearance of divalent Yb surface oxide - in contrast to the bulk macroscopic Yb which is trivalent in the oxide. Our results suggest that at intermediate oxygen exposures "sandwich-like" nanoparticles of YbO/Yb/Al were synthesized. At higher O2 exposures, the oxygen seems to penetrate all the way to the Yb-Al interface. The results of the present study have to be considered when photonic applications of Yb-doped garnet nanoparticles are planned.
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| 39. |
- Zhang, Chaofan, et al.
(författare)
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Radial Structure of Free Yb/YbO Nanoparticles Created by Oxidation Before or After Aggregation with Divalent Instead of Trivalent Oxide
- 2013
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 117:27, s. 14390-14397
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Tidskriftsartikel (refereegranskat)abstract
- Nanoparticles consisting of Yb and its divalent oxide YbO have been created by two different oxidation approaches based on the gas-aggregation method with magnetron sputtering. In one type of nanoparticles, the Yb oxide molecules, created by reactive sputtering before the aggregation, agglomerate predominantly in the interior of mixed-composition nanoparticles. In the other type, the oxide is formed by exposing the preformed metallic Yb nanoparticles to oxygen, which at certain conditions is believed to oxidize primarily the surface of such nanoparticles. Such segregated stoichiometry has been disclosed using Yb 4f core-level photoelectron spectroscopy at a series of oxidation conditions for each type of production. In contrast to a typical macroscopic case where Yb is trivalent, in both production cases, Yb is divalent in the oxide. By using the production methods suggested, it becomes possible to tailor the electronic and thus the physical and chemical properties of such nanoparticles, which are discussed in the literature as building blocks for photonic, electronic, and magnetic nanoscale devices.
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| 40. |
- Zhang, Ruiying, et al.
(författare)
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Comparative phylogeography of two widespread magpies : importance of habitat preference and breeding behavior on genetic structure in China.
- 2012
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Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 65:2, s. 562-72
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Tidskriftsartikel (refereegranskat)abstract
- Historical geological events and climatic changes are believed to have played important roles in shaping the current distribution of species. However, sympatric species may have responded in different ways to such climatic fluctuations. Here we compared genetic structures of two corvid species, the Azure-winged Magpie Cyanopica cyanus and the Eurasian Magpie Pica pica, both widespread but with different habitat dependence and some aspects of breeding behavior. Three mitochondrial genes and two nuclear introns were used to examine their co-distributed populations in East China and the Iberian Peninsula. Both species showed deep divergences between these two regions that were dated to the late Pliocene/early Pleistocene. In the East Chinese clade of C. cyanus, populations were subdivided between Northeast China and Central China, probably since the early to mid-Pleistocene, and the Central subclade showed a significant pattern of isolation by distance. In contrast, no genetic structure was found in the East China populations of P. pica. We suggest that the different patterns in the two species are at least partly explained by ecological differences between them, especially in habitat preference and perhaps also breeding behavior. These dissimilarities in life history traits might have affected the dispersal and survival abilities of these two species differently during environmental fluctuations.
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| 41. |
- Zhang, Shan, et al.
(författare)
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ScaffoMapping: Assisting concept mapping for video learners
- 2019
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Ingår i: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - Cham : Springer International Publishing. - 1611-3349 .- 0302-9743. ; 11747 LNCS, s. 314-328
-
Konferensbidrag (refereegranskat)abstract
- Previous research has shown that having learners construct concept maps can bring better learning outcome. However, in video learning scenario, there is not sufficient support for learners to create concept maps from educational videos. Through a preliminary study, we identified two main difficulties video learners face in creating concept maps: navigation difficulty and learning difficulty. To help users to overcome such difficulties, we design scaffolds to assist learners in concept mapping. We present ScaffoMapping, a system aiming for scaffolded concept map creation on educational videos through automatic concept extraction and timestamp generation. Our study, which compares ScaffoMapping with the baseline approach, shows that (1) Learners can create higher quality concept maps with ScaffoMapping. (2) ScaffoMapping enables better learning outcomes in video learning scenario.
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| 42. |
- Zhang, Tongyan, et al.
(författare)
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Redox-induced partner radical formation and its dynamic balance with radical dimer in cucurbit 8 uril
- 2009
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 11:47, s. 11134-11139
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Tidskriftsartikel (refereegranskat)abstract
- N-(4-Hydroxy-phenoxyethyl)-N'-ethyl-4,4'-bipyridium (1) can form a stable 1 : 1 inclusion complex with CB[8] in aqueous solution, in which the hydroxyphenol (HP) moiety is back-folded and inserted together with the viologen moiety into the cavity of CB[8]. When the ethyl viologen dication (EV2+) in 1 is reduced, chemically or electrochemically, an intramolecular partner radical (EV+center dot-HP)/CB[8] can be detected, meanwhile, a dynamic balance between the partner radical and the intermolecular radical dimer (EV+center dot-HP)(2)/CB[8] can be observed.
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| 43. |
- Zhang, Wei, et al.
(författare)
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Carrier Recombination Processes in Gallium Indium Phosphide Nanowires
- 2017
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 17:7, s. 4248-4254
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Tidskriftsartikel (refereegranskat)abstract
- Understanding of recombination and photoconductivity dynamics of photogenerated charge carriers in GaxIn1-xP NWs is essential for their optoelectronic applications. In this letter, we have studied a series of GaxIn1-xP NWs with varied Ga composition. Time-resolved photoinduced luminescence, femtosecond transient absorption, and time-resolved THz transmission measurements were performed to assess radiative and nonradiative recombination and photoconductivity dynamics of photogenerated charges in the NWs. We conclude that radiative recombination dynamics is limited by hole trapping, whereas electrons are highly mobile until they recombine nonradiatively. We also resolve gradual decrease of mobility of photogenerated electrons assigned to electron trapping and detrapping in a distribution of trap states. We identify that the nonradiative recombination of charges is much slower than the decay of the photoluminescence signal. Further, we conclude that trapping of both electrons and holes as well as nonradiative recombination become faster with increasing Ga composition in GaxIn1-xP NWs. We have estimated early time electron mobility in GaxIn1-xP NWs and found it to be strongly dependent on Ga composition due to the contribution of electrons in the X-valley.
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| 44. |
- Zhao, Yadong, 1985-, et al.
(författare)
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Enhancement of surimi gel properties through the synergetic effect of fucoidan and oligochitosan
- 2023
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Ingår i: Food Hydrocolloids. - : Elsevier BV. - 0268-005X .- 1873-7137. ; 140
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Tidskriftsartikel (refereegranskat)abstract
- For the first time, two common marine-derived dietary fibres (MDFs), fucoidan (FU) and oligochitosan (OCS), were introduced as textural and nutritional enhancers in hairtail surimi gels. The MDFs could assist with inhabiting the endogenous proteolytic enzyme activity, unfolding the myosin to expose more reactive domains, inducing favorable protein conformational transition, and thus, promoting gelation. The highly hydrophilic MDFs rich in -OH groups can bind water molecules via strong hydrogen bonds, facilitating water redistribution within the gel network. Driven by the enhanced chemical forces, a stable protein-FU-OCS gel is obtained, which improves the hardness by almost 100% and the water holding capacity from 86.25% to 92.25%. Collectively, this study demonstrates that MDFs are a group of effective additives to improve gel characteristics and nutritional profiles of surimi-based seafood products. The proposed MDF-protein interaction model would guide the application of MDFs as novel additives in the food industry.
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| 45. |
- Zou, Xianshao, et al.
(författare)
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Carrier Recombination Processes in GaAs Wafers Passivated by Wet Nitridation
- 2020
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 12:25, s. 28360-28367
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Tidskriftsartikel (refereegranskat)abstract
- As one of the successful approaches to GaAs surface passivation, wet-chemical nitridation is applied here to relate the effect of surface passivation to carrier recombination processes in bulk GaAs. By combining time-resolved photoluminescence and optical pump-THz probe measurements, we found that surface hole trapping dominates the decay of photoluminescence, while photoconductivity dynamics is limited by surface electron trapping. Compared to untreated sample dynamics, the optimized nitridation reduces hole- and electron-trapping rate by at least 2.6 and 3 times, respectively. Our results indicate that under ambient conditions, recovery of the fast hole trapping due to the oxide regrowth at the deoxidized GaAs surface takes tens of hours, while it is effectively inhibited by surface nitridation. Our study demonstrates that surface nitridation stabilizes the GaAs surface via reduction of both electron- and hole-trapping rates, which results in chemical and electronical passivation of the bulk GaAs surface.
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