检索结果-南通市图书馆

Research in Astronomy and Astrophysics 2012年第7期12卷 723-734页

作者： Gang zhao Yong-Heng zhao yao-quan Chu Yi-Peng Jing Li-Cai Deng Key Laboratory for Optical Astronomy National Astronomical Observatories Chinese Academyof Sciences Beijing 100012 Chinat University of Science and Technology of China Hefei 230026 China Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China

LAMOST （Large sky Area Multi-Object fiber Spectroscopic Telescope） is a Chinese national scientific research facility operated by National Astronomical Observatories, Chinese Academy of Sciences （NAOC）. After two years of commis- sioning beginning in 2009, the telescope, instruments, software systems and opera- tions are nearly ready to begin the main science survey. Through a spectral survey of millions of objects in much of the northern sky, LAMOST will enable research in a number of contemporary cutting edge topics in astrophysics, such as discovery of the first generation stars in the Galaxy, pinning down the formation and evolution history of galaxies - especially the Milky Way and its central massive black hole, and look- ing for signatures of the distribution of dark matter and possible sub-structures in the Milky Way halo. To maximize the scientific potential of the facility, wide national par- ticipation and international collaboration have been emphasized. The survey has two major components： the LAMOST ExtraGAlactic Survey （LEGAS） and the LAMOST Experiment for Galactic Understanding and Exploration （LEGUE）. Until LAMOST reaches its full capability, the LEGUE portion of the survey will use the available ob- serving time, starting in 2012. An overview of the LAMOST project and the survey that will be carried out in the next five to six years is presented in this paper. The sci- ence plan for the whole LEGUE survey, instrumental specifications, site conditions, and the descriptions of the current on-going pilot survey, including its footprints and target selection algorithm, will be presented as separate papers in this volume.

关键词： techniques: spectroscopic -- Galaxy: structure -- Galaxy: evolution --Galaxy: disk -- spectroscopy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Initial costates derived by near-optimal reference sequence and least-squares method

引用

Chinese Journal of Aeronautics 2024年第5期37卷 377-391页

作者： Shaozhao LU yao ZHANG quan HU School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China

In this paper,we present a novel initial costates solver for initializing time-optimal trajectory problems in relative motion with continuous low *** proposed solver consists of two primary components:training a Multilayer Perceptron(MLP)for generating reference sequence and Time of Flight(TOF)to the target,and deriving a system of linear algebraic equations for obtaining the initial *** overcome the challenge of generating training samples for the MLP,the backward generation method is proposed to obtain five different training *** training database and sample form are determined by analyzing the input and output correlation using the Pearson correlation *** best-performing MLP is obtained by analyzing the training results with various hyper-parameter combinations.A reference sequence starting from the initial states is obtained by integrating forward with the near-optimal control vector from the output of ***,a system of linear algebraic equations for estimating the initial costates is derived using the reference sequence and the necessary conditions for *** results demonstrate that the proposed initial costates solver improves the convergence ratio and reduce the function calls of the shooting ***,Monte-Carlo simulation illustrates that the initial costates solver is applicable to different initial velocities,demonstrating excellent generalization ability.

关键词： Relative motion Expanding training database Multilayer perceptron Initial costates Least-squares method

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Barium charge transferred doped carbon dots with ultra-high quantum yield photoluminescence of 99.6% and applications

引用

Chinese Chemical Letters 2021年第2期32卷 861-865页

作者： yao Liu Jianfei Wei Xiang Yan Ming zhao Chaozhong Guo quan Xu Chongqing Key Laboratory of Materials Surface&Interface Science College of Materials Science and EngineeringChongqing University of Arts and SciencesChongqing 402160China School of Materials Designing and Engineering Beijing Institute of Fashion TechnologyBeijing 100029China School of Materials Science and Engineering Boise UniversityBaise 533000China State Key Laboratory of Heavy Oil Processing Beijing Key Laboratory of Biogas Upgrading UtilizationChina University of Petroleum-BeijingBeijing 102249China

Long-emission carbon dots(CDs) is triggering immense enthusiasm on account of their intrinsic merits of high chemical stability and excellent optical *** this study,a facile and rapid approach was developed for the preparation of barium-doped carbon dots(Ba-CDs) with yellow fluo rescence emission and high quantum *** chemistry and the chemical architecture of the Ba-CDs was revealed under various spectroscopic *** work provides more insights into the effects of charge transfer caused by Ba heteroatoms,which is considered as the most challenging step in the investigation on luminescence ***,the prepared Ba-CDs were successfully applied as fluorescent probes in the detection of trace water in organic solvents(ethanol,isopropanol,acetone,tetrahydrofuran).Comparing with traditional fluorescent probes for water detection in organic solvents,Ba-CDs detection provides a more sensitive,much faster and more economical approach.

关键词： Ba-doped Carbon dots quantum yield Charge transfer Fluorescent sensors

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Analyzing cytokines as biomarkers to evaluate severity of glaucoma

引用

International Journal of Ophthalmology(English edition) 2017年第6期10卷 925-930页

作者： yao Tong Ya-Li Zhou Yan Zheng Manas Biswal Pei-quan zhao zhao-Yang Wang Department of Ophthalmology Shanghai Ninth People＇s Hospital Shanghai Jiaotong University School of Medicine Shanghai 200011 China Department of Ophthalmology Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine Shanghai 200092 China Department of Ophthalmology Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine Chongming Branch Shanghai 202150 China Department of Molecular Genetics University of Florida Gainesville Florida 32610 USA

AIM： To analyze cytokines as biomarkers for evaluation of severity of glaucoma. METHODS： This was a prospective case-control study including 29 eyes with glaucoma. Besides, 28 eyes with senile cataract were used as control. Patients were classified into four groups： acute angle closure glaucoma （AACG）, chronic angle closure glaucoma （CACG）, primary open angle glaucoma （POAG） and senile cataract. Undiluted vitreous samples were collected, then vitreous concentrations of 9 types of cytokines were determined by cytometric bead assay system： y-interferon （IFNg）, interleukin （IL-10, IL-2, IL-4, IL-5, interferon-y-inducible protein （IP）-10, monocyte chemoattractant protein （MCP）-I, tumor necrosis factor （TNF） -Q, and vascular endothelial growth factor （VEGF）. We also recorded the intraocular pressure （lOP） of patients in each group and Pearson correlated analysis was performed to analysis the correlation between each type of cytokine with IOR RESULTS： Vitreous levels of IL-2, iL-5, MCP-1, TNF-a and IP-10 were significantly higher （P〈0.05） in AACG group. Patients with AACG, CACG and POAG have higher lOP than senile cataract, but we didn＇t find any significant correlation between lOP with any type of the cytokines. CONCLUSION： Inflammation and immune reaction have a strong link with the pathology of glaucoma especially AACG, Some cytokines may act as biomarkers to evaluate the severity of glaucoma, Anti-inflammatory treatments and controlling of lOP are necessary for the therapy of glaucoma.

关键词： glaucoma cytokines intraocular pressure

来源：

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

AN ENERGY-STABLE PARAMETRICFINITE ELEMENT METHOD FOR SIMULATING SOLID-STATE DEWETTING PROBLEMS INTHREE DIMENSIONS

引用

Journal of Computational Mathematics 2023年第4期41卷 771-796页

作者： Weizhu Bao quan zhao Department of Mathematics National University of SingaporeSingapore119076

We propose an accurate and energy-stable parametric finite element method for solving the sharp-interface continuum model of solid-state dewetting in three-dimensional *** model describes the motion of the film/vapor interface with contact line migration and is governed by the surface diffusion equation with proper boundary conditions at the contact *** present a weak formulation for the problem,in which the contact angle condition is weakly *** using piecewise linear elements in space and backward Euler method in time,we then discretize the formulation to obtain a parametric finite element approximation,where the interface and its contact line are evolved *** resulting numerical method is shown to be well-posed and unconditionally ***,the numerical method is generalized to the case of anisotropic surface energies in the Riemannian metric *** results are reported to show the convergence and efficiency of the proposed numerical method as well as the anisotropic effects on the morphological evolution of thin films in solid-state dewetting.

关键词： Solid-state dewetting Surface diffusion Contact line migration Contact angle Parametric finite element method Anisotropic surface energy

来源：

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

Synthesis and Absorption Properties of Leaf-like Nd2Cu2O4+δ via a Coordination Complex Method with [NdCu(3,4-pdc)2(OAc)(H2O)5]·6.5H2O Precursor

引用

Chinese Journal of Structural Chemistry 2020年第4期39卷 737-746页

作者： zhao yao YOU Jun-Hua LV Wen-quan FANG Ming School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China Institute of Modern Physics Chinese Academy ofSciences(CAS)Lanzhou 730000China Department of Chemistry Hebei Normal University of Science&TechnologyQinhuangdao 066004China

Nd2Cu2O4+δnanosheets were synthesized via coordination complex method(CCM)by using[NdCu(3,4-pdc)2(OAc)(H2O)5]·6.5H2O(1,3,4-pdc=3,4-pyridinedicarboxylic acid)as the *** to the particles prepared by SSM(simple solution method),Nd2Cu2O4+δprepared by CCM showed leaf-like morphology composed of nanosheets with an average thickness of 50~80 nm and a BET surface area up to 17.9 m^2/*** Nd2Cu2O4+δsamples exhibit selective adsorption towards malachite green(MG)with significant Qm(maximum adsorption capacity)values reaching up 1.55 g/g at room temperature,and the thermodynamic parameters of adsorption process were *** addition,the properties of selective adsorption of the prepared samples were investigated by temperature change tests.

关键词： Nd2Cu2O4+δ coordination-complex method simple solution method selective adsorption malachite green

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Fracture geometry and breakdown pressure of radial borehole fracturing in multiple layers

引用

Petroleum Science 2024年第1期21卷 430-444页

作者： Yu-Ning Yong zhao-quan Guo Shou-Ceng Tian Lu-yao Ma Tian-Yu Wang Mao Sheng National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China Beijing Petroleum Machinery Company Limited CNPC Engineering Technology R&D Company LimitedBeijing102206China Smart Energy Co. LtdChina Xiongan GroupXiong’an New Area071000HebeiChina

Radial borehole fracturing that combines radial boreholes with hydraulic fracturing is anticipated to improve the output of tight oil and gas *** paper aims to investigate fracture propagation and pressure characteristics of radial borehole fracturing in multiple layers.A series of laboratory experiments with artificial rock samples(395 mm×395 mm×395 mm)was conducted using a true triaxial fracturing *** crucial factors corresponding to the vertical distance of adjacent radial borehole layers(vertical distance),the azimuth and diameter of the radial borehole are *** results show that radial borehole fracturing in multiple layers generates diverse fracture *** types of fractures are identified based on the connectivity between hydraulic fractures and radial *** vertical distance significantly influences fracture propagation perpendicular to the radial borehole *** increase in the vertical distance impedes fracture connection across multiple radial borehole layers and reduces the fracture propagation distance along the radial borehole *** azimuth also influences fracture propagation along the radial borehole *** the azimuth reduces the guiding ability of radial boreholes,which makes the fracture quickly curve to the maximum horizontal stress *** breakdown pressure correlates with diverse fracture geometries *** the fractures connect multi-layer radial boreholes,increasing the vertical distance decreases the breakdown *** the azimuth and increasing the diameter also decrease the breakdown *** extrusion force exists between the adjacent fractures generated in radial boreholes in multiple rows,which plays a crucial role in enhancing the guiding ability of radial boreholes and results in higher breakdown *** research provides valuable theoretical insights for the field application of radial borehole fracturing technology in tight oil and g

关键词： Multi-layer radial boreholes Hydraulic fracturing Fracture propagation Pressure characteristic

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Dependence of α-phase size on flow stress during dynamic recrystallization steady state in Ti60 alloy

引用

Rare Metals 2017年第11期36卷 851-857页

作者： hui li zhang-long zhao hong-zhen guo yong-quan ning ze-kun yao kai li vSchool of Materials Science and Engineering NorthwesternPolytechnical University Xi'an 710072 China

The dependence of α-phase size on flow stress was characterized by a proposed kinetic model during dynamic recrystallization （DRX） steady state in Ti60 alloy. Accord- ing to the isothermal compression tests, the influence of deformation parameters on the steady-state flow stress was analyzed and the constitutive equation was established to predict the steady-state flow stress under different defor- mation temperatures and strain rates. A power-law rela- tionship between the DRX average grain size and steady- state flow stress with an exponent of -2 is obtained from the dynamic balance during DRX steady state. The effect of deformation parameters on at-phase size was observed through the microstructure after deformation, and the applicability of the model for Ti60 alloy was verified by the comparison between predicted and experimental data.

关键词： Dynamic recrystallization Steady state Grainsize Ti60 alloy Hot deformation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

水下舰艇扩频通信体制研究

引用

现代电子技术 2025年第01期48卷 107-111页

作者：李尧赵健康龙海辉上海交通大学电子信息与电气工程学院

水下舰艇通信采用的水声通信方式在长距离传输中信号衰减严重，且因为隐蔽性需求信号功率受限，叠加受到多径干扰和海洋背景噪声干扰，通信误码率较高。为此，提出水下舰艇扩频通信体制研究。设计扩频通信体制，利用扩频通信体制拓宽传... 详细信息

水下舰艇通信采用的水声通信方式在长距离传输中信号衰减严重，且因为隐蔽性需求信号功率受限，叠加受到多径干扰和海洋背景噪声干扰，通信误码率较高。为此，提出水下舰艇扩频通信体制研究。设计扩频通信体制，利用扩频通信体制拓宽传输带宽，提升远距离衰减下的通信信噪比；采用类白噪声的伪随机码m序列和OPS序列作为扩频码组建编码序列集，解决白噪声干扰、多径干扰和码分多址的问题。测试结果表明：同等条件下，采用m序列的扩频通信结果更优，可以实现-25 dB下误码率低于1%的可靠通信。经过该方法调制后，剔除了噪声干扰和多径干扰，增强了衰减的高频信号，解决了水下通信远距离衰减、多径干扰、背景噪声干扰等问题。

关键词：水下舰艇通信扩频通信 m序列 OPS序列误码率信噪比

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Calculation and Analysis of Force in Roll System of 20-High Sendzimir Mill

引用

Journal of Iron and Steel Research International 2013年第9期20卷 33-39页

作者： WANG zhao-hui GAO quan-jie YAN Chao XIA Zhi-yong ZHANG yao-bing Key Laboratory of Metallurgical Equipment and Control of Education Ministry Wuhan University of Science and Technology

The calculation of force for a roll system has significant effects on cold roiled thin strip gauge adjustment of a 20-high Sendzimir mill. According to the rolling parameters and rolling plans of a ZR 22B-42 Sendzimir mill in a silicon steel factory, the contact force and the resultant force of each roll in the roll system were calculated both in the static state and in the rolling state through C＋＋ programs. It was found that the contact force between the see ond intermediate driven roll and the back up rolls B and C was much lower than that between the other rolls in static state. The results also demonstrated that the resultant force are 59.5%-62%, 37.7%-40.3%, 87.1%-88.7% and 53.9%-56.7% of the rolling force at the second intermediate driven roll, the second intermediate idler roll, the back-up rolls B and C and the back-up rolls A and D, respectively. It was also revealed that the minimum contact force generated between the first intermediate roll and the second intermediate idler roll is 206.7 kN on the first roll ing pass, and that on the second rolling pass, the minimum contact force generated between the second intermediate driven roll and the back-up roll C is 470.7 kN.

关键词： Sendzimir mill roll system static state rolling force

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：