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So_(2)and SoF_(2)simultaneous detection by single mid-infrared laser based on tunable diode laser absorption spectroscopy

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High Voltage 2024年第4期9卷 786-793页

作者： Yin Zhang yan Li Jin yan Chao Bian Xuan chen Xiaoxing Zhang Hubei Engineering Research Center for Safety Monitoring of New Energy and Power Grid Equipment Hubei University of TechnologyWuhanChina State Grid Jiangsu Electric Power Co. Ltd.Ultra High Voltage BranchNanjingChina

In the detection of multi-component gas based on tunable diode laser absorption spectroscopy(TDLAS),the problem of overlapping interference between the absorption lines of each gas is often *** example,when detecting a gas mixture of sulphur dioxide(So_(2))and thionyl fluoride(SoF_(2)),the characteristic decomposition components of SF6,there is overlapping interference in the absorption lines of the two gases,which makes it difficult to detect the concentration of gases *** view of this problem,a novel method based on support vector regression model used for TDLAS is proposed to detect two gases *** detection results show that the correlation coefficients between the concentration of So_(2)and SoF_(2)and the average value of the second harmonic peak reached 0.992 and *** addition,through model testing,different concentrations of So_(2)and SoF_(2)gas mixture are simultaneously detected,and the resulting maximum errors for measuring So_(2)and SoF_(2)concentrations are less than 7.13×10^(-5)and 0.26×10^(-2).The maximum errors of the measurement results in the verification test are not more than 6.4×10^(-3)and 4.6×10^(-2).Therefore,with assistance of the novel method,the detection of multiple gases by using a single laser is achieved.

关键词： tunable diode absorption

An overview and perspective of identifying lunar craters

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Science China Earth Sciences 2024年第5期67卷 1395-1416页

作者： yan JIANG Changyi Xu Ling chen State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100029China Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100049China

The spatiotemporal evolution of lunar impact craters is crucial for investigating lunar interior structure,internal and external dynamic processes,and interplanetary impact *** in lunar crater identification are reviewed based on topography and gravity data,and the features and mechanisms of topographic or buried craters are analyzed regarding morphology,gravity anomalies,gravity gradients,and the underlying crust-mantle interface *** on the compiled crater catalog,the early lunar impact flux and thermal evolution are further discussed according to the basin ages and their interior *** some ancient impact basins,the crater size-frequency distribution measurements revealed age discrepancies from previous studies,suggesting that the lunar late heavy bombardment event started at~3.95 *** degraded bulge structures of the crust-mantle interface beneath mare basins reveal that these basins formed on the lunar crust surface under high-temperature conditions and underwent prolonged relaxation compared to highland ***,we reveal that the up-to-date identification of lunar buried craters remains inaccurate and incomplete,preventing us from accurately reconstructing lunar and interplanetary impact ***,we propose that a gravity model constructed using localized orthogonal basis functions can be useful for identifying lunar craters.

关键词： Moon Gravity field Craters Impact flux Early evolution

Tailoring the texture and mechanical properties of 3%Y_(2.o_(3)p/ZGK200 composites fabricated by unidirectional and cross rolling followed by annealing

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Journal of Magnesium and Alloys 2024年第4期12卷 1479-1495页

作者： Xihai Li Hong yan Zhiwei Shan Rongshi chen Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering University of Science and Technology of China72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering Shandong University of Science and TechnologyQingdaoShandong 266590China Center for Advancing Materials Performance from the Nanoscale(CAMP-Nano)and Hysitron Applied Research Center in China(HARCC) State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi’an 710049China

3%Y_(2.o_(3)p/ZGK200 composites were subjected to unidirectional rolling(UR)and cross rolling(CR)at 400℃and 350℃followed by annealing at 300℃for 1 *** microstructure,texture and mechanical properties of rolled and annealed composites were systematically *** rolled composites exhibited a heterogeneous microstructure,consisting of deformed grains elongated along rolling direction(RD)and Y_(2.o_(3)particles bands distributed along *** annealing,static recrystallization(SRX)occurred and most deformed grains transformed into equiaxed grains.A non-basal texture with two strong T-texture components was obtained after UR while a non-basal elliptical/circle texture with circle multi-peaks was obtained after CR,indicating that rolling path had great influences on texture of the *** annealing process,R-texture component disappeared or weakened,as results,a non-basal texture with double peaks tilting from normal direction(ND)to transverse direction(TD)and a more random non-basal texture with circle multi-peaks were obtained for UR and CR composites,*** yield strength of rolled composites after UR showed obvious anisotropy along RD and TD while a low anisotropic yield strength was obtained after *** Y_(2.o_(3)particles broke during *** fracture of the composites was attributed to the existence of Y_(2.o_(3)clusters and interfacial debonding between particles and matrix during tension,as a result,the ductility was not as superior as matrix alloy.

关键词： Magnesium matrix composites Unidirectional rolling Cross rolling Texture Mechanical properties

Siliceous mesocellular foam supported Cu catalysts for promoting non-thermal plasma activated Co_(2) hydrogenation toward methanol synthesis

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Frontiers of Chemical Science and Engineering 2024年第7期18卷 55-65页

作者： Yi chen Shaowei chen yan Shao Cui Quan Ningbo Gao Xiaolei Fan Huanhao chen State Key Laboratory of Materials-oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China School of Environmental Science and Engineering Nanjing Tech UniversityNanjing 211816China School of Energy and Power Engineering Xi’an Jiaotong UniversityXi’an 710049China Department of Chemical Engineering School of EngineeringThe University of ManchesterManchester M139PLUK Nottingham Ningbo China Beacons of Excellence Research and Innovation Institute University of Nottingham Ningbo ChinaNingbo 315048China Institute of Wenzhou Zhejiang UniversityWenzhou 325006China

Electrified non-thermal plasma (NTP) catalytic hydrogenation is the promising alternative to the thermal counterparts, being able to be operated under mild conditions and compatible with green electricity/hydrogen. Rational design of the catalysts for such NTP-catalytic systems is one of the keys to improve the process efficiency. Here, we present the development of siliceous mesocellular foam (MCF) supported Cu catalysts for NTP-catalytic Co_(2) hydrogenation to methanol. The findings show that the pristine MCF support with high specific surface area and large mesopore of 784 m2·g−1 and ~8.5 nm could promote the plasma discharging and the diffusion of species through its framework, outperforming other control porous materials (viz., silicalite-1, Sio_(2), and SBA-15). Compared to the NTP system employing the bare MCF, the inclusion of Cu and Zn in MCF (i.e., Cu1Zn1/MCF) promoted the methanol formation of the NTP-catalytic system with a higher space-time yield of methanol at ~275 μmol·g_(cat)^(−1)·h^(−1) and a lower energy consumption of 26.4 kJ^(−1)·mmol_(CH_(3)oH)^(-1) (conversely, ~225 μmol·g_(cat)^(−1)·h^(−1) and ~71 kJ^(−1)·mmol_(CH_(3)oH)^(-1), respectively, for the bare MCF system at 10.1 kV). The findings suggest that inclusion of active metal sites (especially Zn species) could stabilize the Co_(2)/Co-related intermediates to facilitate the surface reaction toward methanol formation.

关键词： non-thermal plasma(NTP)catalysis Cu catalyst Co_(2)hydrogenation methanol siliceous mesocellular foam(MCF)

Molecular packing tuning via chlorinated end group enables efficient binary organic solar cells over 18.5%

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Carbon Energy 2024年第3期6卷 196-203页

作者： Yafeng Li Zhenyu chen Xingzheng yan Ziyi Ge Zhejiang Business Technology Institute NingboZhejiangChina Zhejiang Engineering Research Center for Energy optoelectronic Materials and Devices Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingboZhejiangChina Center of Materials Science and optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina

Designing novel nonfullerene acceptors(NFAs)is of vital importance for the development of organic solar cells(oSC).Modification on the side chain and end group are two powerful tools to construct efficient ***,based on the high-performance L8Bo,we selected 3-ethylheptyl to substitute the inner chain of 2-ethylhexyl,obtaining the backbone of *** we introduced different halogen atoms of fluorine and chlorine on 2-(3-oxo-2,3-dihydro-1Hinden-1-ylidene)malononitrile end group(EG)to construct efficient NFAs named BoN3-F and BoN3-Cl,*** donor D18 was chosen to combine with two novel NFAs to construct oSC ***,D18:BoN3-Cl-based device shows a remarkable power conversion efficiency(PCE)of 18.57%,with a high open-circuit voltage(V_(oC))of 0.907 V and an excellent fill factor(FF)of 80.44%,which is one of the highest binary PCE of devices based on D18 as the ***,BoN3-F-based device shows a relatively lower PCE of 17.79%with a decreased FF of 79.05%.The better photovoltaic performance is mainly attributed to the red-shifted absorption,higher electron and hole mobilities,reduced charge recombination,and enhanced molecular packing in the D18:BoN3-Cl ***,we performed stability tests on two binary systems;the D18:BoN3-Cl and D18:BoN3-F devices maintain 88.1%and 85.5%of their initial efficiencies after 169 h of storage at 85°C in an N2-filled glove box,*** work demonstrates the importance of selecting halogen atoms on EG and provides an efficient binary system of D18:BoN3-Cl for further improvement of PCE.

关键词： binary organic solar cell chlorinated end group molecular packing

Stability of water yield in watersheds

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Science China Earth Sciences 2024年第2期67卷 483-496页

作者： Yu yan Zhiyong LIU Xiaohong chen Liyan HUANG Center for Water Resources and Environment School of Civil EngineeringSun Yat-Sen UniversityGuangzhou510275China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai519082China

The hydrological system of a watershed is intricately influenced by both underlying characteristics and climate *** the variability in water yield is essential for effective water resources management and water security in the context of changing *** this study,we adopted the Budyko framework and leveraged simulations from the CMIP6 model to investigate the compensation effects of climate and underlying characteristics on watershed water *** on Taylor expansion and Budyko framework,we estimated the sensitivity of watershed water yield to climate and underlying characteristics(the first-and second-order partial derivatives).By combining external watershed characteristics(e.g.,water yield ratios and underlying characteristics)with internal sensitivity coefficients,this study further used vine copula and principal component analysis to quantify the stability of watershed water *** findings show:(1)Water-yield changes related to underlying characteristics could be offset by climate-related water-yield changes across all climate zones,maintaining the water yield ratio steady(i.e.,the compensation effects).(2)However,global watersheds will turn more sensitive to underlying characteristics and less sensitive to climate variation in the *** climate-and underlying-related sensitivities increase in watersheds with arid climates.(3)The stability of watershed water yield will gradually diminish in the *** 1901–1950to 2051–2100,the global stability of 280 watersheds drops from 0.054 to 0.021(i.e.,stability index identified by the joint probability).Particularly,the largest change in stability of water yield reaches-0.347±0.18 in arid *** semi-arid,semihumid,and humid regions,the changes are-0.039±0.010,-0.028±0.005,and-0.005±0.002,*** findings provide a reference for the future sustainable water resources development under climate change,highlighting the vulnerability of the water resources in ari

关键词： Hydrological system stability Compensation effects on water yield Sensitivities Budyko-Fu decomposition framework Global watersheds

Coupled DEM-FDM analyses of the effects of falling rock’s shape and impact angle on response of granular cushion and rock shed

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3353-3364页

作者： Jingyu Xue chen Cao Jianhua yan Yaopeng Ji Jianping chen College of Construction Engineering Jilin UniversityChangchun130026China School of Earth Sciences and Engineering Hohai UniversityNanjing210098China

Rock shed is an effective protection measure against *** investigate the influences of falling rock’s shape and impact angle on the impact effect of the cushioned rock shed,a modeling approach for a rock shed with a cushion layer using *** granular cushion is modeled as an aggregate of discrete non-cohesion particles,while the concrete plate and the beam are modeled as *** falling rock with different sphericities and impact angles is modeled as a rigid *** numerical model is validated by comparing the simulation results with experimental and numerical results from previous *** model is applied to analyze the effects of rock shape and impact angle on the dynamic interaction effects between falling rock and cushioned rock shed,including the impact force,transmitted bottom force,penetration depth,and plate *** numerical results show that the variation in the falling rock’s shape has different effects on the falling rock with different impact *** findings could support rock shed design by revealing the limitations of the assumptions in the past research,which may result in unsafe rock sheds for some rockfall cases.

关键词： Rockfall Coupled DEM-FDM analysis Rock’s shape Impact angle Granular cushion Rock shed

Transcription factor Foxp1 is essential for the induction of choroidal neovascularization

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Eye and Vision 2024年第3期10卷 1-12页

作者： Meifang yan Junjian Li Li yan Xue Li Jie-Guang chen School of ophthalmology and optometry and Eye Hospital Wenzhou Medical UniversityState Key Laboratory of OptometryOphthalmology and Vision Scienceand Zhejiang Provincial Key Laboratory of Optometry and Ophthalmology270 Xueyuan RoadWenzhouZhejiang325027People’s Republic of China Joint Shantou International Eye Center(JSIEC)of Shantou University and the Chinese University of Hong Kong ShantouGuangdong515000People’s Republic of China

Background The exudative form of age-related macular degeneration(AMD)is characterized by abnormal blood vessel growth,which is stimulated by vascular endothelial growth factor(VEGF)released from retinal pigment epithelium(RPE).The angiogenic behaviors of vascular endothelial cells in vitro depend on forkhead box protein P1(Foxp1),a transcription repressor widely expressed in human and murine tissues during *** this study,we aimed to determine whether loss of Foxp1 affects laser-induced choroidal neovascularization(CNV)in *** Eye-selective deletion of Foxp1 was obtained by crossing Foxp1flox/flox with Six3-Cre *** photocoagulation was delivered to six-to eight-week-old mice to induce *** expression of Foxp1 and Cre was determined by immunofluorescence in cryostat sections of the *** fluorescein angiography(FFA),optical coherence tomography(oCT),and B4 isolectin staining were applied to analyze the leakage,bulge height,and area of CNV lesions,***-choroid tissues were isolated for the determination of VEGF and pigment epithelium derived factor(PEDF)by Western *** Foxp1 was expressed in retinal ganglion cells,RPE,and the choroidal endothelial *** photocoagulation increased the number of Foxp1+-endothelial cells and induced ***3-Cre reduced Foxp1 expression in RPE but not the endothelium,leading to a lower level of VEGF in the ***1 knockout inhibited pathological angiogenesis and vascular leakage of the laser-induced CNV *** Foxp1 regulates the expression of VEGF in the RPE,and inhibition of Foxp1 could potentially be a novel strategy for the prevention and therapy of neovascularization related to AMD.

关键词： Foxp1 Choroidal neovascularization Angiogenesis Laser photocoagulation Age-related macular degeneration

Underdetermined direction of arrival estimation with nonuniform linear motion sampling based on a small unmanned aerial vehicle platform

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Defence Technology（防务技术） 2024年第3期33卷 352-363页

作者： Xinwei Wang Xiaopeng yan Tai An Qile chen Dingkun Huang Science and Technology on Electromechanical Dynamic Control Laboratory School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing 100081China

Uniform linear array(ULA)radars are widely used in the collision-avoidance radar systems of small unmanned aerial vehicles(UAVs).In practice,a ULA's multi-target direction of arrival(DoA)estimation performance suffers from significant performance degradation owing to the limited number of physical *** improve the underdetermined DoA estimation performance of a ULA radar mounted on a small UAV platform,we propose a nonuniform linear motion sampling underdetermined DoA estimation *** the motion of the UAV platform,the echo signal is sampled at different ***,according to the concept of difference co-array,a virtual ULA with multiple array elements and a large aperture is synthesized to increase the degrees of freedom(DoFs).Through position analysis of the original and motion arrays,we propose a nonuniform linear motion sampling method based on ULA for determining the optimal *** the condition of no increase in the aperture of the physical array,the proposed method obtains a high DoF with fewer sampling runs and greatly improves the underdetermined DoA estimation performance of *** results of numerical simulations conducted herein verify the superior performance of the proposed method.

关键词： Unmanned aerial vehicle(UAV) Uniform linear array(ULA) Direction of arrival(DoA) Difference co-array Nonuniform linear motion sampling method