| 1. |
- Zhang, Zhixin, et al.
(författare)
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Vectorized rooftop area data for 90 cities in China
- 2022
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Ingår i: Scientific Data. - : Springer Nature. - 2052-4463. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Reliable information on building rooftops is crucial for utilizing limited urban space effectively. In recent decades, the demand for accurate and up-to-date data on the areas of rooftops on a large-scale is increasing. However, obtaining these data is challenging due to the limited capability of conventional computer vision methods and the high cost of 3D modeling involving aerial photogrammetry. In this study, a geospatial artificial intelligence framework is presented to obtain data for rooftops using high-resolution open-access remote sensing imagery. This framework is used to generate vectorized data for rooftops in 90 cities in China. The data was validated on test samples of 180 km(2) across different regions with spatial resolution, overall accuracy, and F1 score of 1 m, 97.95%, and 83.11%, respectively. In addition, the generated rooftop area conforms to the urban morphological characteristics and reflects urbanization level. These results demonstrate that the generated dataset can be used for data support and decision-making that can facilitate sustainable urban development effectively.
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| 2. |
- Fenstermacher, M.E., et al.
(författare)
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DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
- 2022
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 62:4
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Tidskriftsartikel (refereegranskat)abstract
- DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.
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| 3. |
- Chen, Zhang, et al.
(författare)
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Making monolayer graphene photoluminescent by electron-beam-activated fluorination approach
- 2023
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 608
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Tidskriftsartikel (refereegranskat)abstract
- The past one and half decades have witnessed a tremendous development of graphene electronics, and the key to the success of graphene is its exceptional properties. The lacking of an inherent bandgap endows graphene with excellent electrical properties but considerably limits its applications in light-emitting and high-performance graphene-based devices. Herein, an approach for the direct writing of semiconducting and photoluminescent fluorinated graphene (C4F) patterns on monolayer graphene by an optimized electron-beam-activated fluorination technique is reported. A series of characterization approaches, such as atomic force microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy were used to demonstrate the successful preparation of C4F for maskless lithography. Specially, a sharp and strong photoluminescence located at the purple light range of ∼380 nm was observed in C4F, demonstrating a desirable semiconducting nature, and the bandgap was further confirmed by follow-up electrical measurements, where the C4F filed-effect transistor exhibited a p-type semiconductor behavior and significantly enhanced on/off ratio. Therefore, this work provides a novel technique for the fabrication of graphene devices for promising electronic and optoelectronic applications, but also opens a route towards the tailoring and engineering of electronic properties of graphene.
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| 4. |
- Grasse, Patricia, et al.
(författare)
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GEOTRACES inter-calibration of the stable silicon isotope composition of dissolved silicic acid in seawater
- 2017
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Ingår i: Journal of Analytical Atomic Spectrometry. - : Royal Society of Chemistry (RSC). - 0267-9477 .- 1364-5544. ; 32:3, s. 562-578
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Tidskriftsartikel (refereegranskat)abstract
- The first inter-calibration study of the stable silicon isotope composition of dissolved silicic acid in seawater, delta Si-30(OH)(4), is presented as a contribution to the international GEOTRACES program. Eleven laboratories from seven countries analyzed two seawater samples from the North Pacific subtropical gyre (Station ALOHA) collected at 300 m and at 1000 m water depth. Sampling depths were chosen to obtain samples with a relatively low (9 mmol L-1, 300 m) and a relatively high (113 mmol L-1, 1000 m) silicic acid concentration as sample preparation differs for low- and highconcentration samples. Data for the 1000 m water sample were not normally distributed so the median is used to represent the central tendency for the two samples. Median delta Si-30(OH)(4) values of +1.66& for the low-concentration sample and +1.25& for the high-concentration sample were obtained. Agreement among laboratories is overall considered very good; however, small but statistically significant differences among the mean isotope values obtained by different laboratories were detected, likely reflecting inter-laboratory differences in chemical preparation including pre-concentration and purification methods together with different volumes of seawater analyzed, and the use of different mass spectrometers including the Neptune MC-ICP-MS (Thermo Fisher (TM), Germany), the Nu Plasma MC-ICP-MS (Nu Instruments (TM), Wrexham, UK), and the Finnigan (TM) (now Thermo Fisher (TM), Germany) MAT 252 IRMS. Future studies analyzing delta Si-30(OH)(4) in seawater should also analyze and report values for these same two reference waters in order to facilitate comparison of data generated among and within laboratories over time.
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| 5. |
- Fu, Jie, et al.
(författare)
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Nanoporous CoP nanowire arrays decorated with carbon-coated CoP nanoparticles: the role of interfacial engineering for efficient overall water splitting
- 2022
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Ingår i: International Journal of Energy Research. - : WILEY. - 0363-907X .- 1099-114X. ; 46:8, s. 11359-11370
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Tidskriftsartikel (refereegranskat)abstract
- The innovative construction of bifunctional non-noble electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is imperative for electrochemical water splitting. Herein, we provide a collaborative self-templating method to prepare a hybrid catalyst of nanoporous CoP nanowire (NWs) arrays decorated with carbon-coated CoP nanoparticles (NPs). Its found that the unique structure and morphology of the resultant catalyst can provide abundant available active sites and faciliatate the rapid H-2/O-2 transmission. Additionally, the N-doped carbon improves the conductivity of the catalyst and prevents the aggregation and deactivation of CoP nanoparticles. Forthermore, the strong coupling and synergistic effects by interface engineering are also conducive to the electrochemical performance. Benefiting from these advantages, the CoP NWs/CoP NPs@NC/CC only needs a low overpotential of 103 mV to achieve 10 mA cm(-2) with a small Tafel slope of 87 mV dec(-1) for HER. When employed in an electrolytic cell as an electrocatalyst for overall water splitting, a low voltage of 1.60 V is required to drive 10 mA cm(-2). This study may provide a novel way to fabricate transitionmetal-based catalysts for water splitting.
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| 6. |
- Zhang, Z., et al.
(författare)
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Carbon mitigation potential afforded by rooftop photovoltaic in China
- 2023
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Ingår i: Nature Communications. - : Nature Research. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Rooftop photovoltaics (RPVs) are crucial in achieving energy transition and climate goals, especially in cities with high building density and substantial energy consumption. Estimating RPV carbon mitigation potential at the city level of an entire large country is challenging given difficulties in assessing rooftop area. Here, using multi-source heterogeneous geospatial data and machine learning regression, we identify a total of 65,962 km2 rooftop area in 2020 for 354 Chinese cities, which represents 4 billion tons of carbon mitigation under ideal assumptions. Considering urban land expansion and power mix transformation, the potential remains at 3-4 billion tons in 2030, when China plans to reach its carbon peak. However, most cities have exploited less than 1% of their potential. We provide analysis of geographical endowment to better support future practice. Our study provides critical insights for targeted RPV development in China and can serve as a foundation for similar work in other countries.
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| 7. |
- Zhang, Kai, et al.
(författare)
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Quantifying the photovoltaic potential of highways in China
- 2022
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 324, s. 119600-
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Tidskriftsartikel (refereegranskat)abstract
- Installing photovoltaic (PV) modules on highways is considered a promising way to support carbon neutrality in China. However, collecting the area of the highway, and precisely assessing the shadow area of the highway under complex terrain remain challenges. That severely hinders the assessment of highway PV potential. To address these challenges, a spatiotemporal model is developed in this study to estimate the annual solar PV potential on highways over the whole Chinese territory. First, the areas of different highway segments are calculated based on highway network and highway toll stations. Second, hourly shadow area on highways created by nearby terrain is estimated based on a digital elevation model (DEM). When calculating the highway PV potential, the solar irradiation received in these shadow areas is regarded as zero. Finally, the PV potential of all lanes and emergency lanes was estimated at the prefecture-level city scale using surface radiation data and radiation assessment models. Based on the highway data with a total mileage of 143,684 km at the end of 2020, the results show that the annual PV potential is 3,932 TW and that the corresponding installed capacity is 700.85 GW, which can generate clean electricity at a rate of up to 629.06 TWh. The annual PV potential of highways in the southeast is greater than that in the northwest owing to the higher highway density in the southeast. This study provides a reference basis for highway PV construction planning and suitably assessment in each region of China for PV highway development.
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| 8. |
- Wang, Shuying, et al.
(författare)
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Application of geopolymers for treatment of industrial solid waste containing heavy metals: State-of-the-art review
- 2023
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 390
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Forskningsöversikt (refereegranskat)abstract
- Metallurgy, mineral processing, waste disposal, and other industries produce large amounts of industrial solid waste containing heavy metals (ISWCHM), which poses a serious threat to the ecological environment. Geopolymers are aluminosilicate inorganic polymers that have the advantages of high strength, good corrosion resistance, and low carbon emission during production. The use of ISWCHM to prepare geopolymers can simultaneously utilize solid waste resources and solidify heavy metals. In this paper, the latest research progress in the preparation of geopolymers from ISWCHM is reviewed, including the preparation techniques, application and solidification/stabilization mechanisms of heavy metals. In addition, we analyze existing research problems and provide an outlook on future research and development directions.
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| 9. |
- Wang, Yuming, et al.
(författare)
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Origins of the open-circuit voltage in ternary organic solar cells and design rules for minimized voltage losses
- 2023
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Ingår i: Nature Energy. - : NATURE PORTFOLIO. - 2058-7546. ; 8:9, s. 978-988
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Tidskriftsartikel (refereegranskat)abstract
- The power conversion efficiency of ternary organic solar cells (TOSCs), consisting of one host binary blend and one guest component, remains limited by large voltage losses. The fundamental understanding of the open-circuit voltage (V-OC) in TOSCs is controversial, limiting rational design of the guest component. In this study, we systematically investigate how the guest component affects the radiative and non-radiative related parts of V-OC of a series of TOSCs using the detailed balanced principle. We highlight that the thermal population of charge-transfer and local exciton states provided by the guest binary blend (that is, the guest-component-based binary blend) has a significant influence on the non-radiative voltage losses. Ultimately, we provide two design rules for enhancing the V-OC in TOSCs: high emission yield for the guest binary blend and similar charge-transfer-state energies for host/guest binary blends; high miscibility of the guest component with the low gap component in the host binary blend. The performance of ternary organic solar cells is limited by voltage losses. Using the detailed balance principle, Wang et al. show how the third component of the blend affects the open-circuit voltage and delineate molecular design rules.
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| 10. |
- Zhang, Qian, et al.
(författare)
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Preparation and hydration of industrial solid waste—cement blends: A review
- 2022
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Ingår i: International Journal of Minerals, Metallurgy and Materials. - : Springer Science and Business Media LLC. - 1869-103X .- 1674-4799. ; 29:12, s. 2106-2116
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Forskningsöversikt (refereegranskat)abstract
- Industrial solid waste (ISW)—cement blends have the advantages of low carbon, low energy consumption, and low pollution, but their clinker replacement level in low carbon cement is generally low. To address this challenge, this study considers the latest progress and development trends in the ISW—cement blend research, focusing on the activation of ISWs, the formation of ISW—cement blends, and their associated hydration mechanisms. After the mechanical activation of ISWs, the D50 (average size) typically drops below 10 µm, and the specific surface area increases above 350 m2/kg. Thermal activation can increase the glassy-phase content and reactivity of ISWs, where the coal gangue activation temperature is usually set at 400–1000°C. Furthermore, the roles of ISWs in the hydration of ISW—cement blends are divided into physical and chemical roles. The physical action of ISWs usually acts in the early stage of the hydration of ISW—cement blends. Subsequently, ISWs participate in the hydration reaction of ISW—cement blends to generate products, such as C—(A)—S—H gels. Moreover, alkali activation affects the hydration kinetics of ISW—cement blends and modifies the proportion of gels. Environmental impacts and costs of ISW—cement blends have also been discussed to guide stakeholders in selecting sustainable ISWs.
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