检索结果-南通市图书馆

Theoretical analysis and numerical simulation of acoustic waves in gas hydrate-bearing sediments

Chinese Physics B 2021年第2期30卷 344-354页

作者： Lin Liu xiu-Mei Zhang xiu-Ming wang State Key Laboratory of Acoustics Institute of AcousticsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100149China Beijing Engineering Research Center of Sea Deep Drilling and Exploration Institute of AcousticsChinese Academy of SciencesBeijing 100190China

Based on Carcione-Leclaire model,the time-splitting high-order staggered-grid finite-difference algorithm is proposed and constructed for understanding wave propagation mechanisms in gas hydrate-bearing *** compressional waves and two shear waves,as well as their energy distributions are investigated in *** particular,the influences of the friction coefficient between solid grains and gas hydrate and the viscosity of pore fluid on wave propagation are *** results show that our proposed numerical simulation algorithm proposed in this paper can effectively solve the problem of stiffness in the velocity-stress equations and suppress the grid dispersion,resulting in higher accuracy compared with the result of the Fourier pseudospectral method used by *** excitation mechanisms of the five wave modes are clearly revealed by the results of ***,it is pointed that,the wave diffusion of the second kind of compressional and shear waves is influenced by the friction coefficient between solid grains and gas hydrate,while the diffusion of the third compressional wave is controlled by the fluid ***,two fluid-solid(gas-hydrate formation)models are constructed to study the mode conversion of various *** results show that the reflection,transmission,and transformation of various waves occur on the interface,forming a very complicated wave field,and the energy distribution of various converted waves in different phases is *** is demonstrated from our studies that,the unconventional waves,such as the second and third kinds of compressional waves may be converted into conventional waves on an *** propagation mechanisms provide a concrete wave attenuation explanation in inhomogeneous media.

关键词： gas hydrate-bearing sediments Carcione-Leclaire model time-splitting staggered-grid finite-difference slow-wave characteristics

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

Multidisciplinary treatment of a patient with necrotizing fasciitis caused by Staphylococcus aureus: A case report

引用

World Journal of Clinical Cases 2019年第21期7卷 3595-3602页

作者： Li-Qian Xu Xin-xiu Zhao Pei-Xia wang ji Yang Yun-Mei Yang Department of Geriatrics The First Affiliated Hospital College of Medicine Zhejiang University

BACKGROUND Necrotizing fasciitis is a severe bacterial skin infection that spreads quickly and is characterized by extensive necrosis of the deep and superficial fascia resulting in the devascularization and necrosis of associated *** of high morbidity and mortality,accurate diagnosis and early treatment with adequate antibiotics and surgical intervention are *** timely identification and treatment of complications are necessary to improve survival of *** SUMMARY We report a case of necrotizing fasciitis caused by Staphylococcus aureus in a patient using high doses of glucocorticoid and suffering from secondary diabetes *** was admitted to our hospital due to redness and oedema of the lower *** admission,necrotizing fasciitis caused by Staphylococcus aureus was considered,and he was discharged after B-ultrasound drainage and multiple surgical *** the process of treatment,multiple organ functions were damaged,but with the help of multi-disciplinary treatment,the patient got better *** The key to successful management of necrotizing fasciitis is an early and accurate *** method of using vacuum sealing drainage in postoperative patients can keep the wound dry and clean,reduce infection rate,and promote wound *** collaboration is a vital prerequisite for successful treatment.

关键词： Necrotizing fasciitis Surgical debridement Vacuum sealing drainage Multidisciplinary treatment Case report

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

Climate Change Impact and Its Contribution Share to Paddy Rice Production in jiangxi, China

引用

Journal of Integrative Agriculture 2014年第7期13卷 1565-1574页

作者： LI Wen-juan TANG Hua-jun QIN Zhi-hao YOU Fei wang xiu-fen CHEN Chang-li ji jian-hua LIU xiu-mei Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences Key Laboratory of Agri-Informatics Ministry of Agriculture/Chinese Academy of Agricultural Sciences International Institute for Earth System Science Nanjing University Institute of Crop Sciences Chinese Academy of Agricultural Sciences Institute of Soil Fertilizer and Resource Environment Jiangxi Academy of Agricultural Sciences

In the study, an improved approach was proposed to identify the contribution shares of three group factors that are climate, technology and input, social economic factors by which the grain production is shaped. In order to calibrate the method, jiangxi Province, one of the main paddy rice producers in China was taken as an example. Based on 50 years （1961-2010） meteorological and statistic data, using GIS and statistical analysis tools, the three group factors that in certain extent impact China＇s paddy rice production have been analyzed quantitatively. The individual and interactive contribution shares of each factor group have been identiifed via eta square （η2）. In the paper, two group ordinary leasr square （OLS） models, paddy models and climate models, have been constructed for further analysis. Each model group consists of seven models, one full model and six partial models. The results of paddy models show that climate factors individually and interactively contribute 11.42-15.25%explanatory power to the variation of paddy rice production in the studied province. Technology and input factors contribute 16.17%individually and another 8.46%interactively together with climate factors, totally contributing about 25%. Social economic factors contribute about 7%of which 4.65%is individual contribution and 2.49%is interactive contribution together with climate factors. The three factor groups individually contribute about 23%and interactively contribute additional 41%to paddy rice production. In addition every two of the three factor groups also function interactively and contribute about 22%. Among the three factor groups, technology and input are the most important factors to paddy rice production. The results of climate models support the results of paddy models, and display that solar radiation （indicated by sunshine hour variable） is the dominate climate factor for paddy rice production.

关键词： climate change food security paddy rice production contribution share China

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

Study of heat transfer by using DEM–CFD method in a randomly packed pebble-bed reactor

引用

Nuclear Science and Techniques 2019年第2期30卷 123-134页

作者： Qiang Niu Na-xiu wang Shanghai Institute of Applied Physics Chinese Academy of Sciences CAS Innovative Academies in TMSR Energy System Chinese Academy of Sciences University of Chinese Academy of Sciences

The pebble-bed reactor is one of the most promising designs for the nuclear energy industry. In this paper,a discrete element method-computational fluid dynamics(DEM-CFD) approach that includes thermal conduction, radiation, and natural convection mechanisms was proposed to simulate the thermal-fluid phenomena after the failure of forced circulation cooling system in a pebble-bed core. The whole large-scale packed bed was created using the DEM technique, and the calculated radial porosity of the bed was validated with empirical correlations reported by researchers. To reduce computational costs, a segment of the bed was extracted, which served as a good representative of the large-scale packed bed for CFD calculation. The temperature distributions simulated with two different fluids in this DEM-CFD approach were in good agreement with SANA experimental data. The influence of the natural convection mechanism on heat transfer must be taken into account for coolants with strong convective capacity. The proposed DEM-CFD methodology offers a computationally efficient and widely applied method for understanding the heat transfer process in a pebble-bed core. The method can also be easily extended to assess the passive safety features of newly designed fluoride-salt-cooled pebble-bed reactors.

关键词： Discrete element method Computational fluid dynamics Pebble bed Heat transfer Natural convection

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

Optimal Generalized Case-Cohort Analysis with Cox's Proportional Hazards Model

引用

Acta Mathematicae Applicatae Sinica 2015年第3期31卷 841-854页

作者： YONG-xiu CAO ji-CHANG YU YAN-YAN LIU School of Mathematics and Statistics Wuhan University School of Statistics and Mathematics Zhongnan University of Economics and Law

Generalized case-cohort design has been proved to be a cost-effective way to enhance the efficiency of large epidemiological cohort. In this article, we propose an inference procedure for estimating the unknown parameters in Cox＇s proportional hazards model in generalized case-cohort design and establish an optimal sample size allocation to achieve the maximum power at a given budget. The finite sample performance of the proposed method is evaluated through simulation studies. The proposed method is applied to a real data set from the National Wilm＇s Tumor Study Group.

关键词： Cox's proportional hazards model generalized case-cohort optimal allocation

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

A Non-axisymmetric Spherical α~2-Dynamo

引用

Chinese Journal of Astronomy and Astrophysics 2006年第2期6卷 227-236页

作者： jie jiang jing-xiu wang National Astronomical Observatories Chinese Academy of Sciences Beijing 100012

Using the Chebyshev-tau method, the generation of oscillatory nonaxisymmetric stellar magnetic fields by the α^2-dynamo is studied in spherical geometry. Following the boundary conditions given by Schubert ＆ Zhang, the spherical α^2-dynamo consists of a fully convective spherical shell with inner radius ri and outer radius ro. A comparison of the critical dynamo numbers of axisymmetric and φ-dependent modes for different thicknesses of the convective shell and different α- profiles leads to the following qualitative results：（i） when the angular factor of α- profile is sin^n θ cosθ （n= 1, 2, 4） the solutions of the α^2dynamo are oscillatory and non-axisymmetric, （ii） the thinner the convective shell, the more easily is the nonaxisymmetric mode excited and the higher is the latitudinal wave number, （iii） the thickness of the outer convective shell has an effect on the symmetries of the magnetic fields.

关键词： stars: magnetic fields - methods: numerical

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

Flow characteristics of nonspherical granular materials simulated with multi-superquadric elements

引用

Particuology 2021年第1期19卷 25-36页

作者： Siqiang wang Shunying ji State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of TechnologyDalian 116023China

The superquadric equation is typically used to mathematically describe nonspherical particles and construct particle shapes with different surface sharpness and aspect ***,nonspherical elements constructed using the superquadric equation are strictly convex,limiting their engineering *** this study,a multi-superquadric model based on a superquadric equation is *** model combines several superquadric elements that can be used to construct concave and convex particle *** tests are performed to examine the applicability of the multi-superquadric *** first involves a comparison of theoretical results for a single spherocylinder impacting a flat *** second involves the formation of a nonspherical granular *** third investigates the effects of the particle shape on the hopper discharge and angle of *** final test evaluates the mixing behaviors of granular materials within a horizontally rotating *** tests demonstrate the applicability of the multi-superquadric approach to nonspherical granular ***,the effects of particle shape on the packing density,discharge rate,angle of repose,and Lacey mixing index are *** indicate that concave particles have a lower packing density,flow rate,and mixing rate and higher angles of repose than convex *** of elements becomes more pronounced for concave particles and results in local cluster structures,thereby enhancing the stability of granular systems and limiting sliding or rotation between nonspherical particles.

关键词： Multi-superquadric approach Nonspherical elements Concave particles Discrete element method Granular materials

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

Derivations and Automorphisms of the Positive Part of the Two-parameter Quantum Group U_(r,s)(B_3)

引用

Acta Mathematica Sinica,English Series 2017年第2期33卷 235-251页

作者： Min LI xiu Ling wang School of Sciences Tianjin University of Science and Technology School of Mathematical Sciences and LPMC Nankai University

We compute the derivations of the positive part of the two-parameter quantum group Ur,s（B3） and show that the Hochschild cohomology group of degree 1 of this algebra is a three- dimensional vector space over the base field C. We also compute the groups of （Hopf） algebra automorphisms of the augmented two-parameter quantized enveloping algebra Ur,s（B3）.

关键词： Two-parameter quantum group ore extension hochschild cohomology group (Hopf) al- gebra automorphism

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

Effects of Destruxin A on Hemocytes Morphology of Bombyx mori

引用

Journal of Integrative Agriculture 2013年第6期12卷 1042-1048页

作者： FAN ji-qiao CHEN xiu-run HU Qiong-bo College of Resources and Environment South China Agricultural University

Destruxin A （DA）, a kind of cyclo-hexadepsipeptide isolated from entomopathogenic fungus, Metarhizium anisopliae, is an inhibitor of insect＇s immunity. But its mechanism has not been clarified yet. In this study, the effects of DA on morphologic changes of in vivo and in vitro hemocytes of silkworm, Bombyx mori, were investigated by means of inverted phase contrast microscopy （IPCM）, fluorescence microscopy （FCM） and environmental scanning electron microscopy （ESEM）. The results indicated that DA was cytotoxic to granulohemocytes （GR） and plasmatocytes （PL）. The LC 50 values of DA against in vitro GR and PL of silkworm were 68.77 and 84.11 μg mL-1, respectively. However, the hemocytes in vivo were more susceptible to DA, although at the extremely low dose of 10 μL of 12.5 μg mL-1 for each insect （i.e., 0.036 μg g-1 body weight, or approximately 0.25 μg mL-1 hemolymph）, DA could induce obviously morphologic alterations of hemocytes in vivo. The results imply that there might be some factors in silkworm＇s hemolymph, which influence the interaction of DA and hemocytes.

关键词： destruxin toxicity hemocytes silkworm

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

Correlation between ^(29)Si polymerization and cementitious activity of coal gangue

引用

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第9期10卷 1334-1340页

作者： ji-xiu ZHANG Heng-hu SUN Yin-ming SUN Na ZHANG Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

A new method for estimating the degree of [SiO4]4-polymerization of coal gangue is presented. The method uses the relative bridging oxygen number (RBO) based on nuclear magnetic resonance (NMR) techniques. X-ray diffraction (XRD) and 29Si NMR techniques have been used to study phase transitions and silicate polymerization of coal gangue calcined at different temperatures or co-calcined. It has been found that phase transition of clay minerals causes silicate polymerization to change with temperature. In this study, cementing activity and RBO were determined to be inversely related. Generally, activated coal gangue with lower RBO had better cementitious activity.

关键词： Degree of polymerization Relative bridging oxygen number (RBO) Nuclear magnetic resonance (NMR) Coal gangue Cementitious activity

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：