检索结果-南通市图书馆

Comparison of Nonlinear Local Lyapunov Vectors with Bred Vectors, Random Perturbations and Ensemble Transform Kalman Filter Strategies in a Barotropic Model

引用

Advances in Atmospheric Sciences 2016年第9期33卷 1036-1046页

作者： jie feng Ruiqiang DING Jianping LI Deqiang LIU State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 College of Earth Science University of Chinese Academy of SciencesBeijing 100049 Global Systems Division Earth System Research Laboratory/Oceanic and Atmospheric Research/National Oceanic and Atmospheric AdministrationBoulderCO80305USA Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information TechnologyChengdu 610225 College of Global Change and Earth System Sciences Beijing Normal UniversityBeijing 100875 Joint Center for Global Change Studies Beijing 100875 Fujian Meteorological Observatory Fuzhou 350001

The breeding method has been widely used to generate ensemble perturbations in ensemble forecasting due to its simple concept and low computational cost. This method produces the fastest growing perturbation modes to catch the growing components in analysis errors. However, the bred vectors （BVs） are evolved on the same dynamical flow, which may increase the dependence of perturbations. In contrast, the nonlinear local Lyapunov vector （NLLV） scheme generates flow-dependent perturbations as in the breeding method, but regularly conducts the Gram-Schmidt reorthonormalization processes on the perturbations. The resulting NLLVs span the fast-growing perturbation subspace efficiently, and thus may grasp more com- ponents in analysis errors than the BVs. In this paper, the NLLVs are employed to generate initial ensemble perturbations in a barotropic quasi-geostrophic model. The performances of the ensemble forecasts of the NLLV method are systematically compared to those of the random pertur- bation （RP） technique, and the BV method, as well as its improved version--the ensemble transform Kalman filter （ETKF） method. The results demonstrate that the RP technique has the worst performance in ensemble forecasts, which indicates the importance of a flow-dependent initialization scheme. The ensemble perturbation subspaces of the NLLV and ETKF methods are preliminarily shown to catch similar components of analysis errors, which exceed that of the BVs. However, the NLLV scheme demonstrates slightly higher ensemble forecast skill than the ETKF scheme. In addition, the NLLV scheme involves a significantly simpler algorithm and less computation time than the ETKF method, and both demonstrate better ensemble forecast skill than the BV scheme.

关键词： ensemble forecasting bred vector nonlinear local Lyapunov vector ensemble transform Kalman filter

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

Modelling of the Slope Solute Loss Based on Fuzzy Neural Network Model

引用

Computer Systems Science & Engineering 2022年第8期42卷 677-688页

作者： Xiaona Zhang jie feng Zhen Hong Xiaona Rui School of Hydrology and Water Resources Nanjing University of Information Science&TechnologyNanjing210044China Water Resources Research Institute China Institute of Water Resources and Hydropower ResearchBeijing100044China Department of Geography and Environmental Sustainability University of OklahomaNorman73071USA Wuxi Research Institute Nanjing University of Information Science&TechnologyWuxi214100China

In regards to soil macropores,the solute loss carried by overland flow is a very complex *** this study,a fuzzy neural network(FNN)model was used to analyze the solute loss on slopes,taking into account the soil *** artificial rainfall simulation experiment was conducted in indoor experimental tanks,and the verification of the model was based on the *** characteristic scale of the macropores,the rainfall intensity and duration,the slope and the adsorption coefficient of ions,were chosen as the input variables to the Sugeno FNN *** cumulative solute loss quantity on the slope was adopted as the output variable of the Sugeno FNN *** were three membership functions,and the type of membership function was gbellmf(generalized bell membership function).The hybrid learning algorithm,which combines the back propagation algorithm with a least square method,was applied to train and optimize the network parameters,and the optimal network parameters were *** simulation results showed that the simulated values were consistent with the measured values.

关键词： Slope solute loss soil macropores fuzzy neural network

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

Preparation of Boron-coated Expandable Graphite and Its Application in Flame Retardant Rigid Polyurethane Foam

引用

Chemical Research in Chinese Universities 2015年第2期31卷 315-320页

作者： XU Dongmei LIU Xiu feng jie HAO Jianwei National Laboratory of Flame Retardant Materials School of Materials Science and Engineering Beijing Institute of Technology Beijing 100081 P. R. China Beijing Institute of Aerospace Testing Technology Beijing 100074 P R. China

A novel boron-coated expandable graphite（BEG） material was prepared by first wrapping polyvinyl alco- hoI（PVA） onto expandable graphite（EG） and then condensing with boric acid. The obtained BEG was characterized by scanning electron microscopy（SEM）, Fourier transform infrared（FT1R） spectroscopy, X-ray photoelectron spec- troscopy（XPS）, and tbermogravimetric analysis（TGA）. The fire performance and mechanical properties of the rigid polyurethane foam（RPUF） filled with BEG were investigated by limiting oxygen index（LOl）, horizontal and vertical burning, cone calorimetry（CONE）, and electronic tensile tests. BEG shows an improved compactness of the char layers upon thermal expansion, which is effective for the flame retardancy of RPUF. With a loading of 10%, RPUF/BEG exhibited a higher LOI, 〉10% reduction in heat release rate and carbon monoxide release, as well as a decrease in smoke release during the beginning of combustion compared to RPUF/EG. Moreover, the compressive strength and modulus of RPUF/BEG were increased. The improved flame retardancy of BEG on RPUF can be attributed to the suppression of the ＂popcorn effect＂ of EG by PVA-boric acid, and the improved mechanical property can be attributed to the presence of PVA.

关键词： Expandable graphite Polyvinyl alcohol Boric acid Rigid polyurethane foam Flame retardancy

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

Analytic solutions of self-similar pulse based on Ginzburg-Landau equation with constant coefficients

引用

Science China(Physics,Mechanics & Astronomy) 2008年第3期51卷 299-306页

作者： feng jie XU WenCheng LI ShuXian LIU SongHao School of Physics&Telecommunication Engineering South China Normal UniversityGuangzhou 510006China Laboratory of Photonic Information Technology School of Information&Optoelectronic Science and EngineeringSouth China Normal UniversityGuangzhou 510006China

Based on the constant coefficients of Ginzburg-Landau equation that considers the influence of the doped fiber retarded time on the evolution of self-similar pulse,the parabolic asymptotic self-similar solutions were obtained by the symmetry reduc-tion algorithm. The parabolic asymptotic amplitude function,phase function,strict linear chirp function and the effective temporal pulse width of self-similar pulse are given in this paper. And these theoretical results are consistent with the numerical simulations.

关键词： gain dispersion parabolic asymptotic self-similarity linear chirp normal group velocity dispersion (GVD) fiber amplifiers

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

不同灵芝菌丝体水提物对乙醇诱导LO2肝细胞损伤的保护作用

引用

食品工业科技 2024年第12期45卷 319-326页

作者：陈亚平刘利平冯杰刘艳芳唐传红颜梦秋张劲松韩伟华东理工大学药学院制药工程与过程化学教育部工程研究中心上海市新药设计重点实验室上海200237 上海市农业科学院食用菌研究所农业农村部南方食用菌资源利用重点实验室国家食用菌工程技术研究中心上海市农业遗传育种重点实验室上海201403

为了探讨不同灵芝菌丝体水提物对乙醇诱导LO2肝细胞损伤的保护作用,本文分析了7种不同灵芝菌株发酵菌丝体水提物对乙醇诱导LO2细胞损伤的保护作用。利用乙醇诱导LO2细胞建立体外肝损伤模型,并以细胞存活率、谷丙转氨酶(Alanine Aminotra... 详细信息

为了探讨不同灵芝菌丝体水提物对乙醇诱导LO2肝细胞损伤的保护作用,本文分析了7种不同灵芝菌株发酵菌丝体水提物对乙醇诱导LO2细胞损伤的保护作用。利用乙醇诱导LO2细胞建立体外肝损伤模型,并以细胞存活率、谷丙转氨酶(Alanine Aminotransferase,ALT)、谷草转氨酶(Aspartate Aminotransferase,AST)、活性氧(Reactive Oxygen Species,ROS)、超氧化物歧化酶(Superoxide dismutase,SOD)、谷胱甘肽(Glutathione,GSH)和丙二醛(Malondiadehyde,MDA)水平为指标考察灵芝菌丝体水提物对乙醇诱导LO2细胞损伤的保护效果。结果表明,7种灵芝菌株的菌丝体水提物均具有不同程度的保护作用。综合比较,G0119与G0154菌丝体的水提物作用效果较优,相较模型组,LO2细胞存活率显著提高(P<0.05),细胞培养液中的ALT、AST活力显著降低(P<0.05),细胞内ROS水平显著降低(P<0.05),SOD活力、GSH含量显著升高(P<0.05),MDA含量显著降低(P<0.05)。经相关性分析,发现水提物中多糖组分2的分子量大小与其保肝活性呈正相关,即分子量越大,活性越强。综上,灵芝菌丝体水提物对乙醇诱导的体外肝损伤起到保护作用,并且G0119与G0154菌株的作用效果较优,其保肝作用与提取物中多糖组分的分子量大小相关。

关键词：灵芝菌丝体水提物乙醇性肝损伤保肝作用

来源：

维普期刊数据库博看期刊

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

Mathematical model of deoxidization with post stirring in a combined blowing converter

引用

International Journal of Minerals,Metallurgy and Materials 2010年第5期17卷 541-545页

作者： jie feng Yan-ping Bao Xun Wu Heng Cui Engineering Research Institute University of Science and Technology Beijing Beijing 100083 China School of Materials Science and Engineering Heibei University of Science and Technology Shijiazhuang 050035 China

Dissolved oxygen in the steel at the terminal of the converter smelting process is the main cause for the formation of oxide inclusions, and the high terminal oxygen content worsens the steel cleanness. However, post stirring in a combined blowing converter can promote the carbon-oxygen reaction in the liquid steel and reduce the dissolved oxygen content at the terminal of the converter smelting process. Thus, the mathematical model of deoxidization in the post stirring process was obtained, and the rationality of which was further verified by industrial tests. Finally, it is concluded that the product of dissolved carbon and oxygen, i.e. w[C]·w[O], decreases obviously after adopting the new technique of post stirring in the combined blowing converter.

关键词： steelmaking converter deoxidization mathematical model

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

Thermal analysis and tests of W/Cu brazing for primary collimator scraper in CSNS/RCS

引用

Nuclear Science and Techniques 2017年第4期28卷 19-23页

作者： jie-Bing Yu Jia-Xin Chen Ling Kang jie-feng Wu Yi-Qing Zou Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Dongguan Neutron Science Center Dongguan 523803 China Institute of Plasma Physics Chinese Academy of SciencesHefei 230031 China

To the transverse beam collimation system in a rapid cycling synchrotron,an important component is the primary collimator,which improves emittance of the beam halo particles such that the particles outside the predefined trajectory can be absorbed by the secondary *** the material properties and power deposition distribution,the beam scraper of the primary collimator is a0.17 mm tungsten foil on a double face-wedged copper block of 121.5 mm x 20 *** heat is transferred to the outside by a φ34 mm copper *** this paper,for minimizing brazing thermal stress,we report our theoretical analysis and tests on brazing the tungsten and copper materials which differ greatly in *** show that the thermal stress effect can be controlled effectively by creating stress relief grooves on the copper block and inserting a tungsten transition layer into the copper *** innovation contributes to the successful R&D of the primary *** this study may be of help for working out a brazing plan of similar structures.

关键词： Scraper of primary collimator of CSNS/RCS W/Cu brazing Thermal analysis Brazing tests

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

Effect of noble metal nanoparticle size on C–N bond cleavage performance in hydrodenitrogenation: a study of active sites

引用

Frontiers of Chemical Science and Engineering 2023年第12期17卷 1986-2000页

作者： Yi-Fan Xue jie feng Yun-Cai Song Wen-Ying Li State Key Laboratory of Clean and Efficient Coal Utilization Taiyuan University of TechnologyTaiyuan 030024China

Breakage of the C-N bond is a structure sensitive process,and the catalyst size significantly affects its *** the active metal nanoparticle scale,the role of catalyst size in C-N bond cleavage has not been clearly ***,Ru catalysts with variable nanoparticle sizes were obtained by modulating the reduction temperature,and the catalytic activity was evaluated using 1,2,3,4-tetrahydroquinoline and o-propylaniline with different C-N bond hybridization patterns as *** showed a 13 times higher reaction rate for sp3-hybridized C-N bond cleavage than sp2-hybridized C-N bond cleavage,while the reaction rate tended to increase first and then decrease as the catalyst nanoparticle size *** concentrations of terrace,step,and corner sites were found in different sizes of Ru *** relationship between catalytic site variation and C-N bond cleavage activity was further investigated by calculating the turnover frequency values for each *** analysis indicates that the variation of different sites on the catalyst is the intrinsic factor of the size dependence of C-N bond cleavage activity,and the step atoms are the active sites for the C-N bond *** Ru nanoparticles are smaller than 1.9 nm,they have a strong adsorption effect on the reactants,which will affect the catalytic performance of the Ru ***,these findings were also confirmed on other metallic Pd/Pt *** role of step sites in C-N bond cleavage was proposed using the density function theory *** reactants have stronger adsorption energies on the step atoms,and step atoms have d-band center nearer to the Fermi *** this case,the interaction with the reactant is stronger,which is beneficial for activating the C-N bond of the reactant.

关键词： sp3 sp2-hybridized C–N bond noble metal nanoparticle catalytic active site turnover frequency DFT

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

脑出血术后颅骨缺损合并脑积水同期行颅骨修补术和脑室-腹腔分流术疗效分析

引用

右江民族医学院学报 2024年第3期46卷 355-358页

作者：冯杰张仁豪李宇姜之全蚌埠医科大学第一附属医院神经外科安徽蚌埠233000

目的分析脑出血术后颅骨缺损合并脑积水同期行颅骨修补术和脑室-腹腔分流术(VP分流术)的疗效。方法选取2021年1月至2023年9月蚌埠医科大学第一附属医院神经外科收治的45例脑出血术后骨缺损合并脑积水患者,观察组为同期行颅骨修补术和VP... 详细信息

目的分析脑出血术后颅骨缺损合并脑积水同期行颅骨修补术和脑室-腹腔分流术(VP分流术)的疗效。方法选取2021年1月至2023年9月蚌埠医科大学第一附属医院神经外科收治的45例脑出血术后骨缺损合并脑积水患者,观察组为同期行颅骨修补术和VP分流术21例,对照组为VP分流术后3个月内行颅骨修补术24例。统计术后并发症发生率,术前、术后2周比较V/Bp值,术前、术后3个月比较NIHSS评分、ADL评分、预后优良率。结果术前观察组与对照组V/Bp值差异无统计学意义(P>0.05);术后2周两组V/Bp值均明显降低,且观察组数值较对照组更低(P0.05);术后3个月观察组与对照组NIHSS、ADL评分均明显改善,且观察组评分较对照组改善更多(P<0.05)。术后3个月预后优良率观察组(95.24%)高于对照组(70.83%)(P<0.05)。术后观察组并发症发生率(4.76%)低于对照组(33.33%)(P<0.05)。结论脑出血术后颅骨缺损合并脑积水患者同期行颅骨修补术和VP分流术术后患者脑积水改善明显、神经功能和生活能力提高、预后优良率高且并发症少,患者术后疗效更好。

关键词：脑出血颅骨缺损脑积水颅骨修补术脑室腹膜分流术

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

中药汤剂治疗膝骨关节炎的研究进展

引用

风湿病与关节炎 2024年第9期13卷 72-76页

作者：李云龙冯文杰河南风湿病医院河南郑州450045

中药汤剂是我国应用最早、最广泛的一种剂型,采用中医辨证论治,制备简单易行,吸收快,能迅速发挥药效。中药汤剂治疗膝骨关节炎(骨痹)有两千多年的历史,中医辨证认为正虚是骨痹的主要病因病机,外邪是其发生的重要条件,瘀血、痰浊、气滞... 详细信息

中药汤剂是我国应用最早、最广泛的一种剂型,采用中医辨证论治,制备简单易行,吸收快,能迅速发挥药效。中药汤剂治疗膝骨关节炎(骨痹)有两千多年的历史,中医辨证认为正虚是骨痹的主要病因病机,外邪是其发生的重要条件,瘀血、痰浊、气滞是其重要病理产物。搜集近年来中药汤剂治疗膝骨关节炎相关文献发现,膝骨关节炎的治疗可分为补肝肾为主、祛邪为主、活血化瘀为主三类,与娄多峰教授的“虚邪瘀”治痹理论相符。

关键词：膝骨关节炎骨痹中药汤剂综述

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：