检索结果-南通市图书馆

Predication of Selective Ring-opening Hydrogenolysis for Furfuryl Alcohol to Produce Pentanediol over Dual-atom Catalysts

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2024年第1期40卷 55-63页

作者： WANG Tingting WANG Jia xi Yongjie HU Bin LI Fuwei State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000P.R.China university of Chinese Academy of Sciences Beijing 100049P.R.China

Selective activation of C-O bond is of fundamental importance in the precise conversion of oxygenates into value-added compounds in an atom-economic and sustainable manner, and meanwhile, the structurally well-defined dual-atoms catalysts (DACs) have been scarcely investigated in this field. In this study, a series of transition metal DACs anchored on nitrogen-doped graphene (TM2.NC, TM=Pt, Ir, Rh, Pd, Ru, Co, Ni and Cu) was constructed to make a comprehensive investigation of their selectivity in the hydrogenative transformation of furfuryl alcohol (FAL), an important biomass platform molecule, to 1,2.pentanediol (1,2.PeD) via selective cleavage of furanic C5-O bond, by density functional theory (DFT) calculations and microkinetic modeling. We found that Ir2.NC demonstrated a high selectivity for the cleavage of furanic C5-O bond to produce 1,2.PeD, while the production of THFAL or 1,5-pentanediol (1,5-PeD) on other TM2.NC catalysts are more favorable. Furthermore, we found that the selective C-O bond cleavage of FAL furan ring is affected by the orbital overlap between the d-orbitals of the anchored metal atoms and the p-orbitals of the adsorbed C atom in FAL, suggesting that the selectivity of the C-O bond cleavage is inextricably related with the electronic property of the anchored metals.

关键词： Furfuryl alcohol Hydrogenation Dual-atom catalyst Density functional theory(DFT)calculation

The study of intelligent algorithm in particle identification of heavy-ion collisions at low and intermediate energies

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第2期35卷 170-182页

作者： Gao-Yi Cheng Qian-Min Su xi-Guang Cao Guo-Qiang Zhang School of Electronic and Electrical Engineering Shanghai University of Engineering ScienceShanghai 201620China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201210China Shanghai Institute of Applied physics Chinese Academy of SciencesShanghai 201800China

Traditional particle identification methods face timeconsuming,experience-dependent,and poor repeatability challenges in heavy-ion collisions at low and intermediate *** urgently need solutions to the dilemma of traditional particle identification *** study explores the possibility of applying intelligent learning algorithms to the particle identification of heavy-ion collisions at low and intermediate *** intelligent algorithms,including XgBoost and TabNet,were selected to test datasets from the neutron ion multi-detector for reaction-oriented dynamics(NIMROD-ISiS)and Geant4 ***-based machine learning algorithms and deep learning algorithms *** show excellent performance and generalization *** additional data features besides energy deposition can improve the algorithm’s performance when the data distribution is *** learning algorithms can be applied to solve the particle identification problem in heavy-ion collisions at low and intermediate energies.

关键词： Heavy-ion collisions at low and intermediate energies Machine learning Ensemble learning algorithm Particle identification Data imbalance

Regional soil moisture simulation for Shaanxi Province using SWAT model validation and trend analysis

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2010年第4期53卷 575-590页

作者： LI Mingxing1,2.MA ZhuGuo1 & DU JiWen3.1 Key Laboratory of Regional Climate-Environment Research for Temperate East Asia,Institute of Atmospheric {2.,Chinese Academy of Sciences,Beijing 10002.,China 2.Graduate university of Chinese Academy of Sciences,Beijing 100049,China 3.Shaanxi Administration of Meteorology,xi’an 710014,China Key Laboratory of Regional Climate-Environment Research for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Graduate university of Chinese Academy of Sciences Beijing China Shaanxi Administration of Meteorology Xi’an China

The soil moisture in Shaanxi Province,a region with complex topography,is simulated using the distributed hydrological model Soil Water Assessment Tool(SWAT).Comparison and contrast of modeled and observed soil moisture show that the SWAT model can reasonably simulate the long-term trend in soil moisture and the spatiotemporal variability of soil moisture in the *** to NCEP/NCAR and ERA40 reanalysis of soil moisture show that the trend of variability in soil moisture simulated by SWAT is more consistent with the *** model results suggested that high soil moisture in surface soil layers appears in the southern Shaanxi with high vegetation cover,and the Qinling mountainous region with frequent orographic *** deeper soil layers,high soil moisture appears in the river basins and *** regional soil moisture showed a generally decreasing trend on all soil layers from 1951 to 2.04,with a stronger and significant decreasing trend in deeper soil layers,especially in the northern parts of the province.

关键词： SWAT soil moisture content simulation validation trend analysis

Quantum statistical entropy corresponding to cosmic horizon in five-dimensional spacetime

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2008年第2期51卷 140-146页

作者： ZHAO Ren1,2.& ZHANG ShengLi1 1 Department of Applied physics, xi’an Jiaotong {2., xi’an 710049, China 2.Department of physics, Shanxi Datong {2., Datong 03.009, China Department of Applied physics Xi’an Jiaotong University Xi’an China Department of physics Shanxi Datong University Datong China

The generalized uncertainty relation is introduced to calculate the quantum statis-tical entropy corresponding to cosmic horizon. By using the new equation of state density motivated by the generalized uncertainty relation, we discuss entropies of Bose field and Fermi field on the background of five-dimensional spacetime. In our calculation, we need not introduce cutoff. There is no divergent logarithmic term in the original brick-wall method. And it is obtained that the quantum statistical en-tropy corresponding to cosmic horizon is proportional to the area of the horizon. Further it is shown that the entropy corresponding to cosmic horizon is the entropy of quantum state on the surface of horizon. The black hole's entropy is the intrinsic property of the black hole. The entropy is a quantum effect. In our calculation, by using the quantum statistical method, we obtain the partition function of Bose field and Fermi field on the background of five-dimensional spacetime. We provide a way to study the quantum statistical entropy corresponding to cosmic horizon in the higher-dimensional spacetime.

关键词： quantum statistical entropy generalized uncertainty relation high-dimensional spacetime

Liquid metal droplet dynamics

在线全文

学校读者我要写书评

暂无评论

Droplet 2024年第1期3卷 61-94页

作者： xi Zhao Mengwen Qiao Yingxin Zhou Jing Liu Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijingChina School of Future Technology University of Chinese Academy of SciencesBeijingChina Department of Biomedical Engineering School of MedicineTsinghua UniversityBeijingChina

The unique properties to combine the dual merits of both liquids and metals together make the gallium‐based liquid metal(LM)droplets a class of unconventional substitute which possess great potential for a group of newly emerging areas,such as stretchable electronics,soft devices,micro sensors and *** addition,LM droplets are undoubtedly an intriguing target worth of pursuing in fundamental hydrodynamic investigations due to their extremely high surface tension nature compared to classical nonmetallic *** the discovery of the diverse transformation phenomena and self‐fueled droplet mollusks of LM that can move automatically in solution via single electricity or even without any external energy supply,tremendous attentions were attracted to this special fluidic object of LM *** the past decade,there has been a proliferation of explorations on LM droplet dynamics,while the involved contents are heterogeneous due to the interfacial physical/chemical activity of the LM and the diversity of the kinetic *** better understand and manipulate the droplet behavior and to promote further development of the LMs,this review is dedicated to summarize the latest progress and presents an overview on basic findings related to LM macrodroplet ***,the extended definition of LM droplets and the corresponding fabrication methods are ***,typical works on LM droplet dynamics are systematically interpreted based on their different behavior ***,the perspectives,main obstacles and challenges restricting the development of LM droplet dynamics are pointed out.

关键词： dynamics behavior doubt

Analytical Model of Non-dispersion-limited Transient Stimulated Raman Scattering in Single-mode Silica Fiber in WDM Optical Communication System

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Lasers 2000年第2期9卷 175-181页

作者： GONG Jiamin FANG Qiang LIU Juan WANG Yongchang (Insitute of modern physics, {2.' an Jiaotang {2., {2.' an 710049, China Department of Telecommunications, {2.' an Institute of Posts and Telecommunications, {2.' an 710061, China ) 西安交通大学陕西西安西安邮电学院陕西西安

The non-dispersion-limited analytic acutions of unidirectional N-channel transient stimulated Raman scattering (SRS) coupling wave equation which governing the propagation of the optical signals in single-mode (SM) silica fiber have been presented. Taking into account the SRS cross coupling among the N- channels, the analytic solutions are applicable to the system with arbitrary channel separation and input signal light power.

关键词： stimulated Raman scattering (SRS) wavelength division multiplexing (WDM) fused silica fiber Raman amplification Raman crosstalk

Multi-source data integration and multi-scale modeling framework for progressive prediction of complex geological interfaces in tunneling

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Underground Space 2024年第2期15卷 1-25页

作者： Jingxiao Wang Peinan Li xiaoying Zhuang xiaojun Li xi Jiang Jun Wu Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China College of Environmental Science and Engineering Donghua UniversityShanghai 201620China Institute of Photonics Department of Mathematics and PhysicsLeibniz University HannoverHannover 30167Germany Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong 100872China College of Civil Engineering Shanghai Normal UniversityShanghai 200233China

A reliable geological model plays a fundamental role in the efficiency and safety of mountain tunnel ***,regional models based on limited survey data represent macroscopic geological environments but not detailed internal geological characteristics,especially at tunnel portals with complex geological *** paper presents a comprehensive methodological framework for refined modeling of the tunnel surrounding rock and subsequent mechanics analysis,with a particular focus on natural space distortion of hard-soft rock interfaces at tunnel *** progressive prediction of geological structures is developed considering multi-source data derived from the tunnel survey and excavation *** improve the accuracy of the models,a novel modeling method is proposed to integrate multi-source and multi-scale data based on data extraction and potential field ***,a regional-scale model and an engineering-scale model are built,providing a clear insight into geological phenomena and supporting numerical *** addition,the proposed framework is applied to a case study,the Long-tou mountain tunnel project in Guangzhou,China,where the dominant rock type is *** results show that the data integration and modeling methods effectively improve model structure *** improved model’s calculation deviation is reduced by about 10%to 2.%in the mechanical *** study contributes to revealing the complex geological environment with singular interfaces and promoting the safety and performance of mountain tunneling.

关键词： Mountain tunnel Geological modeling Multi-source data Progressive prediction Tunnel portals

Preliminary results of the study on wind erosion in the Qinghai-Tibetan Plateau using 13.Cs technique

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2000年第11期45卷 1019-1025页

作者： YAN Ping, DONG Guangrong, ZHANG xinbao & ZHANG Yiyun1. Key Laboratory of Environmental Change and Natural Disaster, the Ministry of Education of China, Beijing Normal university, Beijing 100875, China 2. Institute of Desert Research, Chinese Academy of Sciences, Lanzhou 7{2.000, China {2. Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China 4. Department of physics, Sichuan Union university, Chengdu 610041, China Key Laboratory of Environmental Change and Natural Disaster the Ministry of Education of China Beijing Normal University Beijing China Institute of Desert Research Chinese Academy of Sciences Lanzhou China Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu China Department of physics Sichuan Union University Chengdu China

The worldwide fallout of caesium-13. (13.Cs) associated with the nuclear weapon tests during the 1950s and 1960s has provided a valuable man-made tracer for studies of soil erosion and sediment delivery. But relatively few researchers have used it to estimate wind erosion. In this note, the 13.Cs technique is introduced into the studies of wind erosion and its modern processes inthe Qinghai-Tibetan Plateau. Two 13.Cs reference inventories of 982.11 and 2.3.6.04 Bq · m-2.wereestablished preminarily, distributed in the south and middle-north parts of the studied arearespectively. By analyzing the patterns of 13.Cs depth profiles from sampling sites, the aeolianprocesses of erosion and deposition in nearly 40 years have been revealed, i.e. the shrub coppicedunes (S1) and semi-fixed dunefields (S3. experienced the alternation of erosion and deposition,while the grasslands (S4, S6 and S7) and dry farmlands (S5) suffered erosion only. By using 13.Csmodel, the average wind erosion rates for shrub coppice

关键词： 13.Cs technique Qinghai-Tibetan Plateau wind erosion.

Non-monotonic behavior of jam probability and stretchedexponential distribution in pedestrian counterflow

在线全文

学校读者我要写书评

暂无评论

Chinese physics B 2024年第9期33卷 259-266页

作者： Ze-Hao Chen Zhi-xi Wu Jian-Yue Guan College of Physical Science and Technology Guangxi Normal UniversityGuilin 541004China Lanzhou Center for Theoretical physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory for Quantum Theory and Applications of the Ministry of EducationLanzhou UniversityLanzhou 730000China

We adopt a floor field cellular automata model to study the statistical properties of bidirectional pedestrian flow movingin a straight corridor. We introduce a game-theoretic framework to deal with the conflict of multiple pedestrians tryingto move to the same target location. By means of computer simulations, we show that the complementary cumulative distributionof the time interval between two consecutive pedestrians leaving the corridor can be fitted by a stretched exponentialdistribution, and surprisingly, the statistical properties of the two types of pedestrian flows are affected differently by theflow ratio, i.e., the ratio of the pedestrians walking toward different directions. We also find that the jam probability exhibitsa non-monotonic behavior with the flow ratio, where the worst performance arises at an intermediate flow ratio of around0.2. Our simulation results are consistent with some empirical observations, which suggest that the peculiar characteristicsof the pedestrians may attributed to the anticipation mechanism of collision avoidance.

关键词： traffic and crowd dynamics evolutionary game theory