| 1. |
- Chi, Chaodan, et al.
(författare)
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Si-based InGaAs photodetectors on heterogeneous integrated substrate
- 2021
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Ingår i: Science China: Physics, Mechanics and Astronomy. - : Springer Science and Business Media LLC. - 1674-7348 .- 1869-1927. ; 64:6
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, InGaAs p-i-n photodetectors (PDs) on an InP/SiO2/Si (InPOI) substrate fabricated by ion-slicing technology are demonstrated and compared with the identical device on a commercial InP substrate. The quality of epitaxial layers on the InPOI substrate is similar to that on the InP substrate. The photo responsivities of both devices measured at 1.55 µm are comparable, which are about 0.808–0.828 A W−1. Although the dark current of PD on the InPOI substrate is twice as high as that of PD on the InP substrate at 300 K, the peak detectivities of both PDs are comparable. In general, the overall performance of the InPOI-based PD is comparable to the InP-based PD, demonstrating that the ion-slicing technology is a promising route to enable the high-quality Si-based InP platform for the full photonic integration on a Si substrate.
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| 2. |
- Fu, Xiaozhi, 1990, et al.
(författare)
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Recent Advances on Sorting Methods of High-Throughput Droplet-Based Microfluidics in Enzyme Directed Evolution
- 2021
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Ingår i: Frontiers in Chemistry. - : Frontiers Media SA. - 2296-2646. ; 9
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Forskningsöversikt (refereegranskat)abstract
- Droplet-based microfluidics has been widely applied in enzyme directed evolution (DE), in either cell or cell-free system, due to its low cost and high throughput. As the isolation principles are based on the labeled or label-free characteristics in the droplets, sorting method contributes mostly to the efficiency of the whole system. Fluorescence-activated droplet sorting (FADS) is the mostly applied labeled method but faces challenges of target enzyme scope. Label-free sorting methods show potential to greatly broaden the microfluidic application range. Here, we review the developments of droplet sorting methods through a comprehensive literature survey, including labeled detections [FADS and absorbance-activated droplet sorting (AADS)] and label-free detections [electrochemical-based droplet sorting (ECDS), mass-activated droplet sorting (MADS), Raman-activated droplet sorting (RADS), and nuclear magnetic resonance-based droplet sorting (NMR-DS)]. We highlight recent cases in the last 5 years in which novel enzymes or highly efficient variants are generated by microfluidic DE. In addition, the advantages and challenges of different sorting methods are briefly discussed to provide an outlook for future applications in enzyme DE.
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| 3. |
- Jiang, Sheng, et al.
(författare)
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In Situ Reconstruction of Hole-Selective Perovskite Heterojunction with Graded Energetics Toward Highly Efficient and Stable Solar Cells
- 2023
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Ingår i: Advanced Energy Materials. - : WILEY-V C H VERLAG GMBH. - 1614-6832 .- 1614-6840. ; 13:27
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Tidskriftsartikel (refereegranskat)abstract
- Perovskite solar cells (PSCs) have demonstrated a high power conversion efficiency, however, the large energy loss due to non-radiative recombination is the main challenge for further performance enhancement. Here, a surface treatment strategy is developed by heat-induced decomposition of a thin interlayer 2,7-Naphthaleneditriflate (NAP) to in situ reconstruct perovskite energetics. It is verified that the reconstructed perovskite surface energetics match better with the upper hole transport layer compared to the intrinsic condition. Spontaneous generation of n/n(-) homojunctions between the perovskite film bulk and the surface region promotes hole extraction, enhancing built-in electric field, and thus significantly suppresses charge recombination at such perovskite hole-selective heterojunctions. Moreover, the surface decomposed fluorine-rich complexes passivate the defects and improve the crystallinity of the perovskite film. These advantages are confirmed by a remarkably improved efficiency from 20.52% for the control device to 23.37% for the treated one with excellent stability. The work provides a promising approach of in situ reconstructing perovskite surface and interface for the design of highly efficient and stable PSCs.
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| 4. |
- Kristan, Matej, et al.
(författare)
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The Visual Object Tracking VOT2016 Challenge Results
- 2016
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Ingår i: COMPUTER VISION - ECCV 2016 WORKSHOPS, PT II. - Cham : SPRINGER INT PUBLISHING AG. - 9783319488813 - 9783319488806 ; , s. 777-823
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge VOT2016 aims at comparing short-term single-object visual trackers that do not apply pre-learned models of object appearance. Results of 70 trackers are presented, with a large number of trackers being published at major computer vision conferences and journals in the recent years. The number of tested state-of-the-art trackers makes the VOT 2016 the largest and most challenging benchmark on short-term tracking to date. For each participating tracker, a short description is provided in the Appendix. The VOT2016 goes beyond its predecessors by (i) introducing a new semi-automatic ground truth bounding box annotation methodology and (ii) extending the evaluation system with the no-reset experiment.
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| 5. |
- Muus, Christoph, et al.
(författare)
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Single-cell meta-analysis of SARS-CoV-2 entry genes across tissues and demographics
- 2021
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 27:3, s. 546-559
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Tidskriftsartikel (refereegranskat)abstract
- Angiotensin-converting enzyme 2 (ACE2) and accessory proteases (TMPRSS2 and CTSL) are needed for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cellular entry, and their expression may shed light on viral tropism and impact across the body. We assessed the cell-type-specific expression of ACE2, TMPRSS2 and CTSL across 107 single-cell RNA-sequencing studies from different tissues. ACE2, TMPRSS2 and CTSL are coexpressed in specific subsets of respiratory epithelial cells in the nasal passages, airways and alveoli, and in cells from other organs associated with coronavirus disease 2019 (COVID-19) transmission or pathology. We performed a meta-analysis of 31 lung single-cell RNA-sequencing studies with 1,320,896 cells from 377 nasal, airway and lung parenchyma samples from 228 individuals. This revealed cell-type-specific associations of age, sex and smoking with expression levels of ACE2, TMPRSS2 and CTSL. Expression of entry factors increased with age and in males, including in airway secretory cells and alveolar type 2 cells. Expression programs shared by ACE2(+)TMPRSS2(+) cells in nasal, lung and gut tissues included genes that may mediate viral entry, key immune functions and epithelial-macrophage cross-talk, such as genes involved in the interleukin-6, interleukin-1, tumor necrosis factor and complement pathways. Cell-type-specific expression patterns may contribute to the pathogenesis of COVID-19, and our work highlights putative molecular pathways for therapeutic intervention. An integrated analysis of over 100 single-cell and single-nucleus transcriptomics studies illustrates severe acute respiratory syndrome coronavirus 2 viral entry gene coexpression patterns across different human tissues, and shows association of age, smoking status and sex with viral entry gene expression in respiratory cell populations.
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| 6. |
- Yu, ChaoQing, et al.
(författare)
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Managing nitrogen to restore water quality in China
- 2019
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 567:7749, s. 516-520
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Tidskriftsartikel (refereegranskat)abstract
- The nitrogen cycle has been radically changed by human activities(1). China consumes nearly one third of the world's nitrogen fertilizers. The excessive application of fertilizers(2,3) and increased nitrogen discharge from livestock, domestic and industrial sources have resulted in pervasive water pollution. Quantifying a nitrogen 'boundary'(4) in heterogeneous environments is important for the effective management of local water quality. Here we use a combination of water-quality observations and simulated nitrogen discharge from agricultural and other sources to estimate spatial patterns of nitrogen discharge into water bodies across China from 1955 to 2014. We find that the critical surface-water quality standard (1.0 milligrams of nitrogen per litre) was being exceeded in most provinces by the mid-1980s, and that current rates of anthropogenic nitrogen discharge (14.5 +/- 3.1 megatonnes of nitrogen per year) to fresh water are about 2.7 times the estimated 'safe' nitrogen discharge threshold (5.2 +/- 0.7 megatonnes of nitrogen per year). Current efforts to reduce pollution through wastewater treatment and by improving cropland nitrogen management can partially remedy this situation. Domestic wastewater treatment has helped to reduce net discharge by 0.7 +/- 0.1 megatonnes in 2014, but at high monetary and energy costs. Improved cropland nitrogen management could remove another 2.3 +/- 0.3 megatonnes of nitrogen per year-about 25 per cent of the excess discharge to fresh water. Successfully restoring a clean water environment in China will further require transformational changes to boost the national nutrient recycling rate from its current average of 36 per cent to about 87 per cent, which is a level typical of traditional Chinese agriculture. Although ambitious, such a high level of nitrogen recycling is technologically achievable at an estimated capital cost of approximately 100 billion US dollars and operating costs of 18-29 billion US dollars per year, and could provide co-benefits such as recycled wastewater for crop irrigation and improved environmental quality and ecosystem services.
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| 7. |
- Zhai, Panlong, et al.
(författare)
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Engineering single-atomic ruthenium catalytic sites on defective nickel-iron layered double hydroxide for overall water splitting
- 2021
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Rational design of single atom catalyst is critical for efficient sustainable energy conversion. However, the atomic-level control of active sites is essential for electrocatalytic materials in alkaline electrolyte. Moreover, well-defined surface structures lead to in-depth understanding of catalytic mechanisms. Herein, we report a single-atomic-site ruthenium stabilized on defective nickel-iron layered double hydroxide nanosheets (Ru-1/D-NiFe LDH). Under precise regulation of local coordination environments of catalytically active sites and the existence of the defects, Ru-1/D-NiFe LDH delivers an ultralow overpotential of 18mV at 10mAcm(-2) for hydrogen evolution reaction, surpassing the commercial Pt/C catalyst. Density functional theory calculations reveal that Ru-1/D-NiFe LDH optimizes the adsorption energies of intermediates for hydrogen evolution reaction and promotes the O-O coupling at a Ru-O active site for oxygen evolution reaction. The Ru-1/D-NiFe LDH as an ideal model reveals superior water splitting performance with potential for the development of promising water-alkali electrocatalysts. Rational design of single atom catalyst is critical for efficient sustainable energy conversion. Single-atomic-site ruthenium stabilized on defective nickel-iron layered double hydroxide nanosheets achieve superior HER and OER performance in alkaline media.
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| 8. |
- Zhang, Xiaomeng, et al.
(författare)
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Engineering Single-Atomic Ni-N-4-O Sites on Semiconductor Photoanodes for High-Performance Photoelectrochemical Water Splitting
- 2021
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 143:49, s. 20657-20669
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Tidskriftsartikel (refereegranskat)abstract
- Direct photoelectrochemical (PEC) water splitting is a promising solution for solar energy conversion; however, there is a pressing bottleneck to address the intrinsic charge transport for the enhancement of PEC performance. Herein, a versatile coupling strategy was developed to engineer atomically dispersed Ni-N-4 sites coordinated with an axial direction oxygen atom (Ni-N-4-O) incorporated between oxygen evolution cocatalyst (OEC) and semiconductor photoanode, boosting the photogenerated electron-hole separation and thus improving PEC activity. This state-ofthe-art OEC/Ni-N-4-O/BiVO4 photoanode exhibits a record high photo-current density of 6.0 mA cm(-2) at 1.23 V versus reversible hydrogen electrode (vs RHE), over approximately 3.97 times larger than that of BiVO4, achieving outstanding long-term photostability. From X- ray absorption fine structure analysis and density functional theory calculations, the enhanced PEC performance is attributed to the construction of single-atomic Ni-N-4-O moiety in OEC/BiVO4, facilitating the holes transfer, decreasing the free energy barriers, and accelerating the reaction kinetics. This work enables us to develop an effective pathway to design and fabricate efficient and stable photoanodes for feasible PEC water splitting application.
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| 9. |
- Zhang, Yanting, et al.
(författare)
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Two-Dimensional Defective Boron-Doped Niobic Acid Nanosheets for Robust Nitrogen Photofixation
- 2021
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 15:11, s. 17820-17830
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Tidskriftsartikel (refereegranskat)abstract
- Direct nitrogen photofixation is a feasible solution toward sustainable production of ammonia under mild conditions. However, the generation of active sites for solar-dirven nitrogen fixation not only limits the fundamental understanding of the relationship among light absorption, charge transfer, and catalytic efficiency but also influences the photocatalytic activity. Herein, we report two-dimensional boron-doped niobic acid nanosheets with oxygen vacancies (B-V-o-HNbO3 NSs) for efficient N-2 photofixation in the absence of any scavengers and cocatalysts. Impressively, B-V-o-HNbO3 NS as a model catalyst achieves the enhanced ammonia evolution rate of 170 mu mol g(cat)(-1) h(-1) in pure water under visible-light irradiation. The doublet coupling representing (NH4+)-N-15 in an isotopic labeling experiment and in situ infrared spectra confirm the reliable ammonia generation. The experimental analysis and density functional theory (DFT) calculations indicate that the strong synergy of boron dopant and oxygen vacancy regulates band structure of niobic acid, facilitates photogenerated charge transfer, reduces free energy barriers, accelerates reaction kinetics, and promotes the high rates of ammonia evolution. This work provides a general strategy to design active photocatalysts toward solar N-2 conversion.
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