| 1. |
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- 2019
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Journal article (peer-reviewed)
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| 2. |
- Shang, Yuchen, et al.
(author)
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Ultrahard bulk amorphous carbon from collapsed fullerene
- 2021
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In: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 599:7886, s. 599-604
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Journal article (peer-reviewed)abstract
- Amorphous materials inherit short- and medium-range order from the corresponding crystal and thus preserve some of its properties while still exhibiting novel properties1,2. Due to its important applications in technology, amorphous carbon with sp2 or mixed sp2–sp3 hybridization has been explored and prepared3,4, but synthesis of bulk amorphous carbon with sp3 concentration close to 100% remains a challenge. Such materials inherit the short-/medium-range order of diamond and should also inherit its superior properties5. Here, we successfully synthesized millimetre-sized samples—with volumes 103–104 times as large as produced in earlier studies—of transparent, nearly pure sp3 amorphous carbon by heating fullerenes at pressures close to the cage collapse boundary. The material synthesized consists of many randomly oriented clusters with diamond-like short-/medium-range order and possesses the highest hardness (101.9 ± 2.3 GPa), elastic modulus (1,182 ± 40 GPa) and thermal conductivity (26.0 ± 1.3 W m−1 K−1) observed in any known amorphous material. It also exhibits optical bandgaps tunable from 1.85 eV to 2.79 eV. These discoveries contribute to our knowledge about advanced amorphous materials and the synthesis of bulk amorphous materials by high-pressure and high-temperature techniques and may enable new applications for amorphous solids.
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| 3. |
- Chen, Desui, et al.
(author)
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Shelf-Stable Quantum-Dot Light-Emitting Diodes with High Operational Performance
- 2020
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In: Advanced Materials. - : Wiley-VCH Verlagsgesellschaft. - 0935-9648 .- 1521-4095. ; 32
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Journal article (peer-reviewed)abstract
- Quantum-dot light-emitting diodes (QLEDs) promise a new generation of high-performance, large-area, and cost-effective electroluminescent devices for both display and solid-state lighting technologies. However, a positive ageing process is generally required to improve device performance for state-of-the-art QLEDs. Here, it is revealed that the in situ reactions induced by organic acids in the commonly used encapsulation acrylic resin lead to positive ageing and, most importantly, the progression of in situ reactions inevitably results in negative ageing, i.e., deterioration of device performance after long-term shelf storage. In-depth mechanism studies focusing on the correlations between the in situ chemical reactions and the shelf-ageing behaviors of QLEDs inspire the design of an electron-transporting bilayer, which delivers both improved electrical conductivity and suppressed interfacial exciton quenching. This material innovation enables red QLEDs exhibiting neglectable changes of external quantum efficiency (>20.0%) and ultralong operational lifetime (T-95: 5500 h at 1000 nits) after storage for 180 days. This work provides design principles for oxide electron-transporting layers to realize shelf-stable and high-operational-performance QLEDs, representing a new starting point for both fundamental studies and practical applications.
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| 4. |
- Cui, Song, et al.
(author)
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Polycyclic aromatic hydrocarbons in fresh snow in the city of Harbin in northeast China
- 2019
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In: Atmospheric Environment. - : Elsevier. - 1352-2310 .- 1873-2844. ; 215
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Journal article (peer-reviewed)abstract
- Characterizing levels of polycyclic aromatic hydrocarbons (PAHs) in snow and their toxicity is important for understanding snow scavenging of PAHs and associated human health and environmental risks in cold regions. A total of 48 fresh snow samples were collected from six precipitation events during the winter of 2014-2015 at eight (5 urban, 2 suburban and 1 rural) sites across the heavily industrialized and agricultural city of Harbin in northeast China, and were analyzed for the USEPA priority 16 PAHs. Concentrations of the sum of the 16 PAHs from individual snow samples ranged from 0.3 to 2549.6 pg L-1 or nearly four orders of magnitude. The arithmetic mean concentration (+/- standard deviation) of the 48 samples was 218.1 +/- 623.7 mu g L-1, and the median value was 10.7 mu g L-1. The most abundant PAHs averaged from all the samples were Pyrene (17.1%), followed by Phenanthrene (14.9%), Naphthalene (14.4%), and Fluoranthene (10.2%). The important carcinogenic Sigma(7)PAHs accounted for 58.4% of the total PAHs at locations directly impacted by road traffic. Source apportionment analysis using diagnostic ratios coupled with principal component analysis (PCA) indicated that coal and biomass combustion and vehicle exhausts are the major sources of PAHs in winter. Concentrations of PAHs in snow were significantly correlated with measured levels of PAHs in airborne particulate matter (PM2.5 (R = 0.857, p < 0.05); PM10 (R = 0.831, p < 0.05)), as well as with ambient temperature (R = -0.851, p < 0.05). Almost all (99%) of PAHs measured in the snow were present in particulate phase. The practice of clearing snow by removing it from urban areas and disposing it in suburban and rural areas may create a new pathway of exposure, which needs to be assessed further.
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| 5. |
- Cui, Song, et al.
(author)
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Spatial and temporal variations of open straw burning based on fire spots in northeast China from 2013 to 2017
- 2021
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In: Atmospheric Environment. - : Elsevier. - 1352-2310 .- 1873-2844. ; 244
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Journal article (peer-reviewed)abstract
- Open straw burning releases significant amounts of particulate matter (PM) and trace gases into the air and thus is an important source of atmospheric pollutants in China. In this study, based on fire spots in northeast China from 2013 to 2017, we analyzed pollution concentration degree (PCD) and pollution concentration period (PCP), and assessed spatial and temporal variations of open straw burning. Straw types and burning areas were then determined according to the distributions of fire spots and land use dataset. The amounts of several major atmospheric pollutants (PM10, PM25, CO, NOx and NMVOCs (non-methane volatile organic compounds)) emitted into the atmosphere from open straw burning were estimated according to crop production, Residue/Grain ratio (R/G), combustion efficiency and emission factor. Open straw burning occurred frequently in dry and paddy fields, mainly in areas of West and Northeast Heilongjiang Province, Midwest Jilin Province and Central Liaoning Province. The temporal variations of open straw burning tended to be dispersed with PCD varying from >0.8 during 2013-2015 to <0.4 during 2017 and PCP changing from 28.2 to 36.0 during autumn-winter seasons of 2013-2015 to 5.4-7.9 during winter-spring seasons of 2016-2017. During the five-year period (2013-2017), the total straw yield reached 628.7 million tons, of which 10.9 million tons were open burned in northeast China. The total amounts emitted from open straw burning were 108.9, 106.9, 552.9, 36.9 and 99.4 thousand tons for PM10, PM25, CO, NOx and NMVOCs, respectively. Among these emissions, corn straw burning contributed 81.7%, 81.6%, 71.4%, 86.8% and 74.9% while rice straw burning contributed 18.2%, 18.4%, 28.5%, 13.2% and 25.0%, respectively. Emissions from open straw burning have significant impacts on pollutants ambient concentrations, especially for PM2.5 in the autumn-winter seasons as indicated by their good correlations (p < 0.05).
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| 6. |
- Pecunia, Vincenzo, et al.
(author)
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Roadmap on energy harvesting materials
- 2023
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In: Journal of Physics. - : IOP Publishing. - 2515-7639. ; 6:4
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Journal article (peer-reviewed)abstract
- Ambient energy harvesting has great potential to contribute to sustainable development and address growing environmental challenges. Converting waste energy from energy-intensive processes and systems (e.g. combustion engines and furnaces) is crucial to reducing their environmental impact and achieving net-zero emissions. Compact energy harvesters will also be key to powering the exponentially growing smart devices ecosystem that is part of the Internet of Things, thus enabling futuristic applications that can improve our quality of life (e.g. smart homes, smart cities, smart manufacturing, and smart healthcare). To achieve these goals, innovative materials are needed to efficiently convert ambient energy into electricity through various physical mechanisms, such as the photovoltaic effect, thermoelectricity, piezoelectricity, triboelectricity, and radiofrequency wireless power transfer. By bringing together the perspectives of experts in various types of energy harvesting materials, this Roadmap provides extensive insights into recent advances and present challenges in the field. Additionally, the Roadmap analyses the key performance metrics of these technologies in relation to their ultimate energy conversion limits. Building on these insights, the Roadmap outlines promising directions for future research to fully harness the potential of energy harvesting materials for green energy anytime, anywhere.
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| 7. |
- Cui, Song, et al.
(author)
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Modeling primary and secondary fractionation effects and atmospheric transport of polychlorinated biphenyls through single-source emissions
- 2019
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In: Environmental Geochemistry and Health. - : Springer. - 0269-4042 .- 1573-2983. ; 41:5, s. 1939-1951
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Journal article (peer-reviewed)abstract
- The Chinese Gridded Industrial Pollutants Emission and Residue Model (ChnGIPERM) was used to investigate potential fractionation effects and atmospheric transport of polychlorinated biphenyls (PCBs) derived from single-source emissions in China. Modeling the indicative PCBs (CB28, CB101, CB153, and CB180) revealed spatiotemporal trends in atmospheric transport, gas/particle partitioning, and primary and secondary fractionation effects. These included the inference that the Westerlies and East Asian monsoons affect atmospheric transport patterns of PCBs by influencing the atmospheric transport time (ATT). In this study, dispersion pathways with long ATTs in winter tended to have short ones in summer and vice versa. The modeled partitioning of PCB congeners between gas and particles was mainly controlled by temperature, which can further influence the ATT. The potential for primary and secondary fractionation was explored by means of numerical simulations with single-source emissions. Within ChnGIPERM, these phenomena were mainly controlled by the temperature and soil organic carbon content. The secondary fractionation of PCBs is a slow process, with model results suggesting a timescale of several decades.
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| 8. |
- Cui, Song, et al.
(author)
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Optimization preparation of biochar from garden waste and quantitative analysis for Cd2+ adsorption mechanism in aqueous solution
- 2024
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In: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 14:12, s. 12761-12773
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Journal article (peer-reviewed)abstract
- To develop a market for biochar, it is imperative that solutions are found to producing biochars that are both high performance and economically viable. While biochar performance can be enhanced via chemical modification, it is likely that optimization of pyrolysis time and temperature is a more cost-effective approach to enhancing performance. This was explored via the transformation of urban garden waste into biochar using a range of preparation conditions (heating temperature, residence time, and heating rate). Biochar yield and Cd2+ adsorption performance were optimized using response surface methodology. The "best compromise" yield and Cd2+ adsorption performance (49.9% and 40.0 mg/g, respectively) of garden waste biochar were achieved using preparation conditions of 398 degrees C, 10 degrees C/min, and 30 min. In addition, the quantification of adsorption mechanisms suggested mineral precipitation, ion exchange, functional group complexation, and physical adsorption, accounted for 47.9%, 41.5%, 10.3%, and 0.3% of total adsorbed Cd2+ in biochar, respectively. Overall, transformation of garden waste into adsorbents might offer a new market for the utilization of urban garden waste, especially given the size of this waste stream and the challenges it presents to municipal administrations.
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| 9. |
- Sun, Zhenxing, et al.
(author)
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Fluorescein-guided surgery for spinal gliomas : Analysis of 220 consecutive cases
- 2020
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In: NOVEL THERAPEUTIC ADVANCES IN GLIOBLASTOMA. - LONDON ENGLAND : Elsevier. - 9780128211144 ; , s. 139-154
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Book chapter (peer-reviewed)abstract
- Objective: Sodium fluorescein (FL) is widely used as a fluorescent tracer for brain tumor resection. However, FL-guided resection of spinal gliomas has been reported only occasionally. To evaluate the safety, characteristics, and usefulness of FL-guided surgery in the resection of spinal glioma. Methods: Between January 2015 and December 2018, 220 consecutive patients with 227 spinal gliomas underwent FL-guided resection using the Zeiss Pentero 900 surgical microscope with an integrated YELLOW 560 filter. FL evaluation and clinical outcomes were analyzed. Results: No FL-related complications occurred in this series. Entire tumor fluorescence was observed in 161 (70.93%) gliomas, nodular fluorescence in 46 (20.26%) tumors, and no fluorescence in 20 (8.81%) tumors. The intraoperative fluorescence of 217 (95.59%) gliomas was highly correlated with preoperative contrast-enhancing magnetic resonance imaging, except in eight ependymomas, one pilocytic astrocytoma, and one diffuse midline glioma. Gross-total resection was achieved in 78.85% (179/227) of spinal gliomas, including 94.30% (149/158) ependymal tumors and 43.48% (30/69) astrocytic and oligodendroglial tumors. At the final clinical follow-up, the spinal function of 75 (33.04%) patients showed significant improvement, 105 (46.26%) showed stabilization, and 47 (20.70%) showed deterioration. Conclusion: FL is a safe and useful real-time tool that could enhance tumor borders or residual tumors and hence increase the gross-total resection rate in cases with contrast-enhanced tumors.
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| 10. |
- Yang, Zhenxing, et al.
(author)
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Tuning the band gap and the nitrogen content in carbon nitride materials by high temperature treatment at high pressure
- 2018
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In: Carbon. - : Elsevier. - 0008-6223 .- 1873-3891. ; 130, s. 170-177
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Journal article (peer-reviewed)abstract
- Carbon nitride (C-N) materials have been attracting great interest because of their extraordinary performance in photocatalysis and energy conversion. However, developing an effective strategy for achieving band-gap engineering of C-N materials to satisfy practical applications remains highly desired. Here we report an efficient way to tune the band gap and control the nitrogen stoichiometry in carbon nitride compounds by using high pressure and high temperature (HPHT) treatment. It is found that treating a g-C3N4 precursor at relatively low temperature (630oC and below) under pressure can efficiently narrow the band gap even down to the red light region (~600 nm), increase the crystallinity, and significantly improve the charge carrier separation efficiency (by two orders of magnitude), almost without changing their stoichiometry. When increasing the treatment temperature under pressure, nitrogen-doped graphene/graphite materials with weak ferromagnetism were obtained. We thus obtained C-N materials with tunable band gaps, ranging from semiconducting to metallic states. XPS measurements show that pyridinic nitrogen is preferentially eliminated under such HPHT conditions while graphitic nitrogen is preserved in the C-N network. Our results thus provide an efficient strategy for tuning the structure and physical properties of C-N materials for applications.
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