检索结果-南通市图书馆

Characterization of Gallic Acid Interaction with Human Serum Albumin by Spectral and Molecular Modeling Methods

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2012年第2期28卷 287-290页

作者： LIU zuo-jia LI Dan NIU Feng-lan School of Public Health Jilin UniversityChangchun 130021P.R.China

The binding of drugs with human serum albumin（HSA） is a crucial factor influencing the distribution and bioactivity of drugs in the *** understand the action mechanisms between gallic acid（GA,3,4,5-trihydroxybenzoic acid） and HSA,the binding of GA with HSA was investigated by a combined experimental and computational *** fluorescence properties of HSA and the binding parameters of GA collectively indicate that the binding is characterized by static quenching mechanism at one high affinity binding *** to the estimated molecular distance between the donor（HSA） and the acceptor（GA）,the binding is related to the fluorescence resonance energy *** indicated by the thermodynamic parameters,hydrophobic interaction plays a major role in the GA-HSA ***,the experimental results reveal that GA is bound in the large hydrophobic cavity of subdomain IIA in the site I of HSA,which is well approved by molecular docking.

关键词： Gallic acid Human serum albumin Fluorescence quenching Molecular modeling

Corpus-based research on English word recognition rates in primary school and word selection strategy

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2017年第3期18卷 362-372页

作者： Wen-yan XIAO Ming-wen WANG Zhen WENG Li-lin ZHANG jia-li zuo School of Computer Information Engineering Jiangxi Normal UniversityNanchang 330022China jiangxi University of Science and Technology Nanchang 330003China

Acquiring vocabulary is important when studying English, as it assists in listening, speaking, reading, and writing. In this paper, we develop an English webpage corpus(EWC) and create a word frequency list using web crawler technology. By comparing EWC word lists with the British National Corpus(BNC), we find that the BNC word frequency list possesses the feature of timeliness. We also explore primary school students' English word recognition rates by comparing the word frequency lists of several corpora, including EWC, BNC, SUBTLEX-US, and Subtitle Corpus of Children's BBC(CBBC). The results show that the word recognition rates for primary school children are relatively low in both general language and specific language register. Motivated by the experiment results, we finally propose some word-selection strategies for compiling English textbooks for Chinese primary school students.

关键词： Corpus Primary English Recognition rate Word frequency Coverage rate

An application of the LTP＿DSEF model to heavy precipitation forecasts of landfalling tropical cyclones over China in 2018

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2020年第1期63卷 27-36页

作者： zuo jia Fumin REN Dalin ZHANG Chenchen DING Mingjen YANG Tian FENG Boyu CHEN Hui YANG State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Department of Atmospheric and Oceanic Science University of MarylandCollege ParkMaryland 20742USA Department of Atmospheric Sciences “National''Taiwan UniversityTaipei 10617China College of Atmospheric Sciences Chengdu University of Information TechnologyChengdu 610225China National Meteorological Center Beijing 100081China

Recently, a track-similarity-based Dynamical-Statistical Ensemble Forecast(LTP_DSEF) model has been developed in an attempt to predict heavy rainfall from Landfalling Tropical cyclones(LTCs). In this study, the LTP_DSEF model is applied to predicting heavy precipitation associated with 10 LTCs occurring over China in 2018. The best forecast scheme of the model with optimized parameters is obtained after testing 3452 different schemes for the 10 LTCs. Then, its performance is compared to that of three operational dynamical models. Results show that the LTP_DSEF model has advantages over the three dynamical models in predicting heavy precipitation accumulated after landfall, especially for rainfall amounts greater than 250 mm. The model also provides superior or slightly inferior heavy rainfall forecast performance for individual LTCs compared to the three dynamical models. In particular, the LTP_DSEF model can predict heavy rainfall with valuable threat scores associated with certain LTCs, which is not possible with the three dynamical models. Moreover, the model can reasonably capture the distribution of heavier accumulated rainfall, albeit with widespread coverage compared to observations. The preliminary results suggest that the LTP_DSEF model can provide useful forecast guidance for heavy accumulated rainfall of LTCs despite its limited variables included in the model.

关键词： Landfalling tropical cyclones Heavy precipitation forecasts LTP DSEF model

Linearized waveform inversion for vertical transversely isotropic elastic media:Methodology and multi-parameter crosstalk analysis

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第1期21卷 252-271页

作者： Ke Chen Lu Liu Li-Nan Xu Fei Hu Yuan Yang jia-Hui zuo Le-Le Zhang Yang Zhao National Key Laboratory of Petroleum Resources and Engineering Unconventional Petroleum Research InstituteChina University of Petroleum(Beijing)Beijing102249China Aramco Beijing Research Center Aramco AsiaBeijing100102China University of Lausanne LausanneCH-1015Switzerland Bureau of Geophysical Prospecting China National Petroleum CorporationZhuozhou 072750HebeiChina

Seismic migration and inversion are closely related techniques to portray subsurface images and identify hydrocarbon *** migration aims at obtaining structural images of subsurface geologic *** specifically,seismic migration estimates the reflectivity function(stacked average reflectivity or pre-stack angle-dependent reflectivity)from seismic reflection *** the other hand,seismic inversion quantitatively estimates the intrinsic rock properties of subsurface *** seismic inversion methods are applicable to detect hydrocarbon reservoirs that may exhibit lateral variations in the inverted *** there exist many differences,pre-stack seismic migration is similar with the first iteration of the general linearized seismic ***,seismic migration and inversion techniques assume an acoustic or isotropic elastic *** reservoirs such as shale and tight sand formation have notable anisotropic *** present a linearized waveform inversion(LWI)scheme for weakly anisotropic elastic media with vertical transversely isotropic(VTI)*** is based on two-way anisotropic elastic wave equation and simultaneously inverts for the localized perturbations(ΔVp_(0)/Vp_(0)/Vs_(0)/Vs_(0)/,Δ∈,Δδ)from the long-wavelength reference *** proposed VTI-elastic LWI is an iterative method that requires a forward and an adjoint operator acting on vectors in each *** derive the forward Born approximation operator by perturbation theory and adjoint operator via adjoint-state *** inversion has improved the quality of the images and reduces the multi-parameter crosstalk comparing with the adjoint-based *** have observed that the multi-parameter crosstalk problem is more prominent in the inversion images for Thomsen anisotropy ***,the Thomsen parameter is the most difficult to *** also analyze the multi-parameter crosstalk using scattering radiation patte

关键词： Elastic Anisotropy Least-squares imaging Waveform inversion Computational geophysics

Extracting angle-domain common-image gathers in VTI media using ansiotropic-Helmholtz P/S wave-mode decomposition

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2023年第3期20卷 1546-1561页

作者： Le-Le Zhang Yang Zhao Lu Liu Ke Chen jia-Hui zuo Yi-Xin Wang Ji-Dong Yang State Key Laboratory of Petroleum Resource and Prospecting Unconventional Petroleum Research InstituteChina University of PetroleumBeijing102249China Aramco Beijing Research Center Aramco AsiaBejing100102China Department of Geophysics China University of Petroleum(East China)QingdaoShandong266580China

Common-image gathers are extensively used in amplitude versus angle(AVA)and migration velocity analysis(MVA).The current state of methods for anisotropic angle gathers extraction use slant-stack,local Fourier transform or low-rank approximation,which requires much *** on an anisotropic-Helmholtz P/S wave-mode decomposition method,we propose a novel and efficient approach to produce angle-domain common-image gathers(ADCIGs)in the elastic reverse time migration(ERTM)of VTI *** start with,we derive an anisotropic-Helmholtz decomposition operator from the Christoffel equation in VTI media,and use this operator to derive the decomposed formulations for anisotropic P/S ***,we employ the first-order Taylor expansion to calculate the normalized term of decomposed formulations and obtain the anisotropic-Helmholtz decomposition method,which generates the separated P/S wavefields with correct amplitudes and ***,we develop a novel way that uses the anisotropic-Helmholtz decomposition operator to define the polari-zation angles for anisotropic P/S waves and substitute these angles to decomposing *** polarization angles are then calculated directly from the separated vector P-and S-wavefields and converted to the phase *** ADCIGs are thusly produced by applying the phase angles to VTI *** addition,we develop a concise approximate expression of residual moveout(RMO)for PP-reflections of flat reflectors in VTI media,which avoids the complex transformations between the group angles and the phase *** approximate RMO curves show a good agreement with the exact solution and can be used as a tool to assess the migration velocity *** demonstrated by two selected examples,our ADCIGs not only produce the correct kinematic responses with regards to different velocity pertubatation,but also generate the reliable amplitude responses versus different *** final stacking images of ADCIGs data exhibit the identical im

关键词： Helmholtz decomposition Angle gathers Anisotropy Elastic-RTM

Energy efficient resource allocation for D2D multicast communications

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2019年第11期26卷 3034-3044页

作者： zuo jia-kuo YANG Long-xiang College of Internet of Things Nanjing University of Posts and TelecommunicationsNanjing 210003China College of Telecommunications&Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China

The resource allocation for device-to-device(D2D)multicast communications is *** achieve fair energy efficiency(EE)among different multicast groups,the max-min fairness criterion is used as the optimization criterion and the EE of D2D multicast groups are taken as the optimization objective *** aim is to maximize the minimum EE for different D2D multicast groups under the constraints of the maximum transmit power and minimum transmit rate,which is modeled as a non-convex and mixed-integer fractional programming ***,suboptimal resource allocation algorithms are proposed to solve this ***,channel assignment scheme is performed to assign channel to D2D multicast ***,for a given channel assignment,iterative power allocation schemes with and without loss of cellular users’rate are completed,*** results corroborate the convergence performance of the proposed *** addition,compared with the traditional throughput maximization algorithm,the proposed algorithms can improve the energy efficiency of the system and the fairness achieved among different multicast groups.

关键词： D2D energy efficiency resource allocation max-min fairness criterion fractional programming

On the Improvement of the DSAEF_LTP Model to Heavy Precipitation Simulation of Landfalling Tropical Cyclones over China in 2018

在线全文

学校读者我要写书评

暂无评论

Journal of Tropical Meteorology 2021年第3期27卷 232-245页

作者： CHEN Yu-xu jia Li jia zuo DING Chen-chen REN Fu-min LI Guo-ping College of Atmospheric Sciences Chengdu University of Information TechnologyChengdu 610225 China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081 China

In this study,the Dynamical-Statistical-Analog Ensemble Forecast model(DSAEF_LTP model)for landfalling tropical cyclone(LTC)precipitation was employed to simulate the precipitation of 10 LTCs that occurred over China in *** similarity region scheme(SRS)parameter values added and TC intensity introduced to the generalized initial value(GIV),four groups of precipitation simulation experiments were designed to verify the forecasting ability of the improved model for more TC *** show that the simulation ability of the DSAEF_LTP model can be optimized regardless of whether adding SRS values only,or introducing TC intensity into GIV,while the experiment with both the two improvements shows a more prominent advantage in simulating the heavier precipitation of *** with four NWP models(i.e.,ECMWF,GFS,GRAPES and SMS-WARMS),the overall forecasting performance of the DSAEF_LTP model achieves a better result in simulating precipitation at the thresholds over 250 mm and performs slightly better than NWP models at the thresholds over 100 mm.

关键词： landfalling tropical cyclone heavy precipitation simulation the DSAEFLTP model similarity region scheme

Chemical composition analysis on industrial scale ingots and castings of TiAl alloys

在线全文

学校读者我要写书评

暂无评论

China Foundry 2020年第6期17卷 441-446页

作者： Xian-fei Ding Yi-qun Zhao jia-bin zuo Xin Feng Hai Nan Yong-feng Liang Yan-qing Su Cast Titanium Alloy R&D Center Beijing Institute of Aeronautical MaterialsBeijing 100095China Beijing Engineering Research Center of Advanced Titanium Alloy Precision Forming Technology Beijing 100095China BAIMTEC Material Co. Ltd.Beijing 100094China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology HarbinHarbin150001China

The chemical composition variation of the TiAl-4722 alloys was examined in a batch of the industrial scale master ingots,and in the corresponding castings prepared by conventional vacuum arc remelting(VAR)combined with induction skull melting(ISM)and investment casting *** content changes of major elements and interstitial elements were evaluated based on the chemical analysis at the top and bottom of the ingots and *** show that the contents of C,N,H,Fe and Si have almost no change in the ingots and castings,suggesting that the chemical analysis on these elements can be based on the batch *** O content keeps almost the same in different ingots,but exhibits relatively large differences in castings,which was probably influenced by the reaction between the shell mold and the molten alloy,and the spalling of face coat of the shell mold during *** the major elements of Al,Nb and Cr,the composition difference between the top and the bottom of the ingots is less than that of the *** for the O element,the trend is different,especially for the castings,suggesting that the investment casting is a homogenization process for Cr and Nb,but a differentiation process for *** contents of major elements in castings fluctuate mainly in the same range as that in the ingots,indicating that the contents of the major elements are controllable during investment casting.

关键词： TiAl alloys melting casting chemical composition casting ingot

在线全文

学校读者我要写书评

暂无评论

太中银铁路中宁黄河特大桥桥式方案研究

铁道工程学报 2013年第12期30卷 36-40页

作者：左家强铁道第三勘察设计院集团有限公司天津300142

研究目的:太原至中卫至银川铁路全长近千公里,桥梁设计时速200 km,沿线地形、地质情况复杂。太中正线在宁夏自治区中宁县市跨越黄河,位于八度震区(地震动峰值加速度值为0.20g),同时为满足通航及黄河水利委员会对桥梁跨度的相关要求,必... 详细信息

研究目的:太原至中卫至银川铁路全长近千公里,桥梁设计时速200 km,沿线地形、地质情况复杂。太中正线在宁夏自治区中宁县市跨越黄河,位于八度震区(地震动峰值加速度值为0.20g),同时为满足通航及黄河水利委员会对桥梁跨度的相关要求,必须采用大跨结构。为此,确定适合的桥跨形式成为设计中的控制因素。本文根据桥位处自然情况,结合外部要求,并以地震力分析为重点,开展中宁黄河特大桥主桥桥式方案研究。研究结论:通过对预应力混凝土长联连续梁和多跨简支钢桁梁桥式方案比较,得出:(1)钢桁梁地震作用小,符合结构体形简单、受力明确、自重轻、刚度和质量匀称、重心低的抗震设计原则;(2)钢桁梁便于抢修,跨越重要河流时具有较重要的军事意义;(3)钢桁梁温度跨度较小,避免了设置轨道温度调节器对行车舒适性的影响;(4)本文可以为高度震区大跨度桥梁的桥式方案选择提供一定的理论依据,对其他铁路桥梁的桥型选用具有一定参考意义。

关键词：太中银铁路中宁黄河特大桥桥式方案研究