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Projected change in precipitation forms in the Chinese Tianshan Mountains based on the Back Propagation Neural Network Model

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Journal of Mountain Science 2022年第3期19卷 689-703页

作者： REN Rui LI Xue-mei LI Zhen LI Lan-hai HUANG Yi-yu Faculty of Geomatics Lanzhou Jiaotong UniversityLanzhou 730070China Key Laboratory of Regional Climate-Environment in Temperate East Asia Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Xinjiang institute of Ecology and Geography Chinese Academy of SciencesUrumqi 830011China National-Local Joint Engineering Research Center of Technologies and Applications for National Geographic State Monitoring Lanzhou 730070China Gansu Provincial Engineering Laboratory for National Geographic State Monitoring Lanzhou 730070China

In the context of global warming,precipitation forms are likely to transform from snowfall to rainfall with a more pronounced *** change in precipitation forms will inevitably affect the processes of regional runoff generation and confluence as well as the annual distribution of *** researchers used precipitation data from the CMIP5 model directly to study future precipitation trends without distinguishing between snowfall and ***5 models have been proven to have better performance in simulating temperature but poorer performance in simulating *** overcome the above limitations,this paper used a Back Propagation Neural Network(BNN)to predict the rainfall-to-precipitation ratio(RPR)in months experiencing freezing-thawing transitions(FTTs).We utilized the meteorological(air pressure,air temperature,evaporation,relative humidity,wind speed,sunshine hours,surface temperature),topographic(altitude,slope,aspect)and geographic(longitude,latitude)data from 28 meteorological stations in the Chinese Tianshan Mountains region(CTMR)from 1961 to 2018 to calculate the RPR and constructed an index system of impact *** on the BNN,decision-making trial and evaluation laboratory method(BP-DEMATEL),the key factors driving the transformation of the RPR in the CTMR were *** found that temperature was the only key factor affecting the transformation of the RPR in the BP-DEMATEL *** the relationship between temperature and the RPR,the future temperature under different representative concentration pathways(RCPs)(RCP2.6/RCP4.5/RCP8.5)provided by 21 CMIP5 models and the meteorological factors from meteorological stations were input into the BNN model to acquire the future RPR from 2011 to *** results showed that under the three scenarios,the RPR in the number of months experiencing FTTs during 2011-2100 will be higher than that in the historical period(1981-2010)in the ***,in terms of spatial variation,

关键词： Global warming Tianshan Mountains region Precipitation forms CMIP5 models Back Propagation Neural Network Model

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^(235)U enrichment detection system for nuclear fuel rod based on compact D–D neutron generator

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Science China(Technological Sciences) 2021年第9期64卷 1940-1946页

作者： WU Kang LIU XingYu YANG Xu LIU ChangQi HUO DongYing BAI XiaoHou HAN Chao JIANG QiaoYue ZHANG Hang PENG JinQiu ZHANG Yu WANG JunRun YAO ZeEn WEI Zheng School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China Engineering Research Center for Neutron Application Ministry of EducationLanzhou UniversityLanzhou 730000China

A reliable ^(235)U enrichment uniformity detection system based on a compact D–D neutron generator is developed to detect the ^(235)U enrichment uniformity of different fuel elements in the same nuclear fuel rod. The high-yield compact D–D neutron generator provides 2.45 MeV D–D neutrons, decelerated by a moderator to thermal neutrons or epithermal neutrons, thereby inducing ^(235)U fission to produce highly excited state fission fragments that undergo de-excitation via γ-ray emission. The system detects the ^(235)U enrichment uniformity of a nuclear fuel rod by measuring γ-rays and establishing a relationship between the γ-ray count rate and ^(235)U enrichment in nuclear fuel. The proposed system yields a confidence probability of 99.99% for a relative ^(235)U enrichment deviation of 10% and a neutron yield of 5 × 10^(8) n/s, and the detection accuracy increases with increasing neutron yield. Furthermore, the developed system can satisfy quality control requirements for nuclear fuel production to promote the safe development of nuclear power.

关键词： compact D–D neutron generator ^(235)U enrichment detection BGO crystal

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Subtraction of liposome signals in cryo-EM structural determination of protein-liposome complexes

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Chinese physics B 2024年第8期33卷 569-577页

作者：李首卿李明王玉梅李雪明 institute of physics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory for Protein Sciences of Ministry of Education School of Life SciencesTsinghua UniversityBeijing 100084China State Key Laboratory of Membrane Biology School of Life SciencesTsinghua UniversityBeijing 100084China Tsinghua–Peking Joint Center for Life Sciences Beijing 100084China Beijing Frontier Research Center for Biological Structure Beijing 100084China School of Life Sciences Tsinghua UniversityBeijing 100084China Beijing Branch of Songshan Lake Materials Laboratory Beijing 100190China

Reconstituting membrane proteins in liposomes and determining their structure is a common method for determining membrane protein structures using single-particle cryo-electron microscopy(cryo-EM).However,the strong signal of liposomes under cryo-EM imaging conditions often interferes with the structural determination of the embedded membrane ***,we propose a liposome signal subtraction method based on single-particle two-dimensional(2D)classification average images,aimed at enhancing the reconstruction resolution of membrane *** analyzed the signal distribution characteristics of liposomes and proteins within the 2D classification average images of protein–liposome complexes in the frequency *** on this analysis,we designed a method to subtract the liposome signals from the original particle *** the subtraction,the accuracy of single-particle three-dimensional(3D)alignment was improved,enhancing the resolution of the final 3D *** demonstrated this method using a PIEZO1-proteoliposome dataset by improving the resolution of the PIEZO1 protein.

关键词： cryo-EM protein–liposome complexes liposome signal subtraction 2D classification averaging

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A Case Study on the Rapid Rain-to-Snow Transition in Late Spring 2018 over Northern China:Effects of Return Flows and Topography

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Journal of Meteorological Research 2022年第1期36卷 107-127页

作者： Wenlong ZHANG Xiaopeng CUI Bolong DUAN Bo YU Runxia GUO Haiwen LIU institute of Urban Meteorology China Meteorological AdministrationBeijing 100089 Key Laboratory of Cloud-Precipitation physics and Severe Storms Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 lanzhou Central Meteorological Observatory Lanzhou 730020 Beijing Weather Forecast Center Beijing 100089 Department of Aviation Meteorology Civil Aviation University of ChinaTianjin 300300 University of Chinese Academy of Sciences Beijing 100049

Phase changes in the precipitation processes of early winter and late spring in midlatitude regions represent challenges when forecasting the timing and magnitude of *** 4 April 2018,a heavy snow process occurred in Beijing and northwestern Hebei Province,becoming the most delayed occurrence of heavy spring snow ever recorded over Beijing in the last 30 *** paper uses observational and numerical simulation data to investigate the causes for the rapid rain-to-snow(RRTS)phase transition during this *** following results are obtained.(1)Return flows(RFs),an interesting type of easterly wind,including those at 1000,925,and 800 hPa,played an important role in this heavy snow process and presented a characteristic"sandwich"*** RFs,complex topography,and snow particles that dominated the clouds,were the three key factors for the RRTS transition.(2)The RRTS transition in the plains was directly related to the RF at 925 hPa,which brought about advective cooling initiated approximately 4-6 h before the onset of ***,the RF played a role of diabatic cooling when snow particles began to fall at the onset of precipitation.(3)The RRTS transition in the northern part of the Taihang Mountains was closely related to the relatively high altitude that led to a lower surface temperature owing to the vertical temperature lapse *** immediately before and after the onset of precipitation,the snow particles in clouds entrained the middle-level cold air downward,causing the melting layer(from surface to the 0℃-isotherm level)to become very thin;and thus the snow particles did not have adequate time to melt before falling to the ground.(4)The rapid RRTS over the Yanqing mountainous area in the northwest of Beijing could have involved all the three concurrent mechanisms:the advective cooling of RF,the melting cooling of cloud snow particles,and the high-altitude *** with that in the plain area with less urbanization the duration

关键词： midlatitude heavy snow return flow phase transition Bohai Sea cold pool complex terrain numerical simulation

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Methacrylated gelatin and platelet-rich plasma based hydrogels promote regeneration of critical-sized bone defects

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Regenerative Biomaterials 2024年第4期3卷 66-81页

作者： Shichao Lian Zhiyu Mu Zhengchao Yuan Muhammad Shafiq Xiumei Mo Weidong Mu Department of Traumatic Orthopaedics Shandong Provincial HospitalShandong UniversityJinanShandong 250012China Zoucheng People’s Hospital ZouchengShandong 273500China Department of Medical physics and Biomedical Engineering University of LondonLondon WC1E 6BTUK State Key Laboratory for Modification of Chemical Fibers and Polymer Materials Shanghai Engineering Research Center of Nano-Biomaterials and Regenerative MedicineCollege of Biological Science and Medical EngineeringDonghua UniversityShanghai 201620PR China Innovation Center of NanoMedicine(iCONM) Kawasaki Institute of Industrial PromotionKawasaki-KuKawasaki 210-0821Japan

Physiological repair of large-sized bone defects requires instructive scaffolds with appropriate mechanical properties,biocompatibility,biodegradability,vasculogenic ability and *** objective of this study was to fabricate in situ injectable hydrogels using platelet-rich plasma(PRP)-loaded gelatin methacrylate(GM)and employ them for the regeneration of large-sized bone *** performed various biological assays as well as assessed the mechanical properties of GM@PRP hydrogels alongside evaluating the release kinetics of growth factors(GFs)from *** GM@PRP hydrogels manifested sufficient mechanical properties to support the filling of the tissue *** biofunction assay,the GM@PRP hydrogels significantly improved cell migration and ***,transcriptome RNA sequencing of human umbilical vein endothelial cells and bone marrow-derived stem cells were performed to delineate vascularization and biomineralization abilities of GM@PRP *** GM@PRP hydrogels were subcutaneously implanted in rats for up to 4 weeks for preliminary biocompatibility followed by their transplantation into a tibial defect model for up to 8 weeks in *** defects treated with GM@PRP hydrogels manifested significant bone regeneration as well as angiogenesis,biomineralization,and collagen *** on the biocompatibility and biological function of GM@PRP hydrogels,a new strategy is provided for the regenerative repair of large-size bone defects.

关键词： large-sized bone defect repair platelet-rich plasma hydrogel tissue scaffold gelatin methacrylate

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Synthesis of Novel Tartaric Acid-derived Chiral Phosphite Ligands and Their Application in the Cu-catalyzed Conjugate Addition of Diethylzinc to Cyclic Enones

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Chemical Research in Chinese Universities 2015年第5期31卷 756-760页

作者： PANG Zengbo XING Aiping WANG Lailai State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 P R. China University of Chinese Academy of Sciences Beo'ing 100039 P. R. China

Five novel tropos （3R,4R）- and/or （3S,4S）-N-benzyltartarimide-derived biphenylphosphite ligands were synthesized and applied in the Cu-catalyzed asymmetric conjugate addition of diethylzinc to cyclic enones with up to 75% e.e. Compared with the reported ligand 1-N-benzylpyrrolidine-3,4-bis[（R）-1,1＇-binaphthyl-2,2＇-diyl]phosphite- L-tartaric acid, the issue that L-（＋）-tartaric acid backbone and （R）-binaphthyl showed strong matched/mismatched character was solved with these tropos ligands. It was found that the enantioselectivity was mainly controlled by the absolute configuration of N-benzyltartarimide backbone, and both enantiomers of the addition products can be obtained by simply changing the configuration of N-benzyltartarimide substituent.

关键词： L-(+)- and/or D-(-)-tartaric acid Phosphite ligand 1,4-Conjugate addition Copper salt Cyclic enone

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Properties of Linear Entropy in k-Photon Jaynes-Cummings Model with Stark Shift and Kerr-Like Medium

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Communications in Theoretical physics 2010年第5期53卷 931-936页

作者：廖庆洪 Muhammad Ashfaq Ahmad 王月媛刘树田 Department of physics Harbin Institute of Technology Department of physics COMSATS Institute of Information Technology

The time evolution of the linear entropy of an taking into consideration Stark shift and Kerr-like medium. atom in k-photon daynes-Cummings model is investigated The effect of both the Stark shift and Kerr-like medium on the linear entropy is analyzed using a numerical technique for the field initially in coherent state and in even coherent state. The results show that the presence of the Kerr-like medium and Stark shift has an important effect on the properties of the entropy and entanglement. It is also shown that the setting of the initial state plays a significant role in the evolution of the linear entropy and entanglement.

关键词： k-photon Jaynes Cummings model linear entropy stark shift Kerr-like medium

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Theoretical and experimental investigations of the enantioselective epoxidation of olefins catalyzed by manganese complexes

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Chinese Chemical Letters 2022年第3期33卷 1515-1518页

作者： Jin Lin Fang Wang Jing Tian Jisheng Zhang Yong Wang Wei Sun State Key Laboratory for Oxo Synthesis and Selective Oxidation Center for Excellence in Molecular SynthesisSuzhou Research Institute of LICPLanzhou Institute of Chemical Physics(LICP)Chinese Academy of SciencesLanzhou 730000China institute of Drug Discovery Technology Ningbo UniversityNingbo 315211China University of Chinese Academy of Sciences Beijing 100049China

The enantioselective epoxidation of olefin by Mn^(II)(R,R-PMCP)(OTf)2, H_(2)O_(2) and H_(2)SO_(4) was explored by DFT calculations and experiments. Theoretical results suggest that [Mn^(V)(O)(R,R-PMCP)(SO_(4))]^(+) species with a triplet ground spin state serves as the active species for the olefin epoxidation. It can be generated by the H_(2)SO_(4) assisted O-O heterolysis of Mn^(III)(OOH) species. Mn^(III)-persulfate is also involved in this system, but it cannot promote the olefin epoxidation directly, preferring instead to transform into Mn^(V)(O). Actually, the asymmetric epoxidation reactions with H_(2)O_(2)/H_(2)SO_(4) or Oxone provide similar enantioselectivity in the presence of manganese catalyst. These observations further support the transformation of Mn^(III)-persulfate to Mn^(V)(O) species.

关键词： Epoxidation of olefins Manganese complexes Metal oxo Enantioselective DFT

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MHD Equilibrium Configuration Reconstructions for HL-2A Tokamak

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Plasma Science and Technology 2011年第4期13卷 424-430页

作者：何志雄董家齐何宏达蒋海滨高喆张锦华 Southwestern institute of physics Department of Engineering physics Tsinghua University institute for Fusion Theory and Simulation Zhejiang University Department of Engineering physics Tsinghua University

The EFIT （Equilibrium Fitting） code is modified for the equilibrium configuration reconstruction in HL-2A. Signals from Langmuir probe （LP） at the divertor target plates are employed in the reconstruction of divertor configurations. The results show that discharge #2895 starts with a limiter configuration and develops gradually into a divertor configuration after t = 230 ms. This transition process is clearly demonstrated by the LP signals for the reconstruction. The profiles of plasma parameters such as safety factor q, pressure and current density as well as the evolution of major shape parameters of plasma, such as the boundary magnetic fluxes, the positions of both x-point and magnetic axis, are calculated from the reconstructed configurations. The possibility to apply the method to the swing of strike point on the target plate is discussed.

关键词： equilibrium reconstruction MHD equilibrium LP signals HL-2A tokamak

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AC-DC Fuzzy Linear Active Disturbance Rejection Control Strategy of Front Stage of Bidirectional Converter Based on V2G

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Energy Engineering 2023年第4期120卷 1045-1065页

作者： Guosheng Li Qingquan Lv Zhenzhen Zhang Haiying Dong School of New Energy and Power Engineering Lanzhou Jiaotong UniversityLanzhou730070China State Grid Gansu Electric Power Research institute Lanzhou730070China

Aiming at the problems of output voltage fluctuation and current total harmonic distortion(THD)in the front stage totem-pole bridgeless PFC of two-stage V2G(Vehicle to Grid)vehicle-mounted bi-directional converter,a fuzzy linear active disturbance rejection control strategy for V2G front-stage AC-DC power conversion system is ***,the topologicalworkingmode of the totem-pole bridgeless PFC is analyzed,and themathematical model is *** with the system model and the linear active disturbance rejection theory,a double closed-loop controller is designed with the second-order linear active disturbance rejection control as the voltage outer loop and PI control as the current inner *** controller can realize self-adaptive tuning of the proportional gain coefficient of the active disturbance rejection controller through fuzzy reasoning and realize self-adaptive *** and experimental results show that this method can better solve the problems of slow system response and high total harmonic distortion rate of input current and effectively improve the system’s robustness.

关键词： V2G totem-pole bridgeless PFC fuzzy linear auto disturbance rejection robustness

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