检索结果-南通市图书馆

Soil hydraulic conductivity and its influence on soil moisture simulations in the source region of the Yellow River——take Maqu as an example

引用

Research in Cold and Arid Regions 2019年第5期11卷 360-370页

作者： DongYu jia Jun wen xin Wang ZuoLiang Wang Lanzhou City University LanzhouGansu 730070China Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730030China Key Laboratory of Geographic Information Science Ministry of EducationSchool of Geographic SciencesEast China Normal UniversityShanghai 200241China College of Atmospheric Sciences Plateau Atmosphere and Environment Key Laboratory of Sichuan ProvinceChengdu University of Information TechnologyChengduSichuan 610225China

Saturated hydraulic conductivity and unsaturated hydraulic conductivity which are influenced by soil are two important factors that affect soil water *** this paper,data supplied by the Chinese Academy of Sciences are used to determine true unsaturated hydrology ***,in combination with observed,model simulation and experimental data,an improved saturated hydraulic conductivity parameterization scheme is carried out in CLM4.5 at a single point in the *** main results show that:(1)After improving saturated hydraulic conductivity in CLM4.5 through a parameterization modification,it is found that shallow layer soil moisture increases compared to the initial value;and(2)The numerical values of unsaturated hydraulic conductivities in the model are obviously larger than experimental *** substituting the BrooksCorey soil water characteristic curve into the Mualem model,the value of unsaturated hydraulic conductivity is modified;(3)By using the modified value,it is found that the attenuating magnitude of simulated soil moisture caused by each rainfall event is *** soil moisture variation in shallow layers(5,10 and 20 cm)could be better displayed.

关键词： soil hydraulic conductivity soil moisture source region of the Yellow River observation

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

Endoscopic findings and clinicopathologic characteristics of colonic schistosomiasis:A report of 46 cases

引用

World Journal of Gastroenterology 2010年第6期16卷 723-727页

作者： Cao, Jun Liu, wen-jia Xu, xin-Yun Zou, Xiao-Ping Nanjing Univ Dept Gastroenterol Nanjing Gulou Hosp Sch Med Nanjing 210008 Jiangsu Prov Peoples R China Nanjing Univ Dept Pathol Nanjing Gulou Hosp Sch Med Nanjing 210008 Jiangsu Prov Peoples R China

AIM:To make a retrospective analysis of endoscopy findings and clinicopathologic characteristics of colonic schistosomiasis in order to further improve our understanding of the disease and decrease its misdiagnosis. METHODS:Endoscopy findings and clinicopathologic characteristics of 46 intestinal schistosomiasis patients were retrospectively *** the patients underwent colonoscopy and all biopsy specimens stained with hematoxylin and eosin were observed under a light microscope. RESULTS:Of the 46 colonic schistosomiasis patients,1 was diagnosed as acute schistosomal colitis,16 as chronic schistosomal colitis and 29 as chronic active schistosomal colitis according to their endoscopic findings and *** all patients were suspected of or diagnosed as colonic *** the 12 misdiagnosed patients,4 were misdiagnosed as ulcerativecolitis,1 as Crohn's disease,and 7 as ischemic *** segments of rectum and sigmoid colon were involved in 29 patients(63.0%) .Intact Schistosoma ova were deposited in colonic mucosa accompanying infiltration of eosinocytes,lymphocytes,and plasma cells in acute schistosomal colitis *** fibrosis was found in chronic schistosomal colitis *** the 17 patients with a signal polyp,hyperplastic polyp,canalicular adenoma with a low-grade intraepithelial neoplastic change,tubulovillous adenoma with a highgrade intraepithelial neoplastic change were observed in 10,5,and 2 patients,*** out of the 46 patients were diagnosed as colonic carcinoma. CONCLUSION:Endoscopy contributes to the diagnosis of colonic schistosomiasis although it is nonspecific. A correct diagnosis of colonic schistosomiasis can be established by endoscopy in combination with its clinicopathologic characteristics.

关键词： Colonic schistosomiasis Colonoscopy Diagnosis Pathology

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

Responses of Planetary Waves to Global Warming: Implications from CMIP3 4×CO_2 Experiments

引用

Atmospheric and Oceanic Science Letters 2013年第2期6卷 109-116页

作者： wen xin-Yu jia Zhe TAN Ben-Kui Department of Atmospheric and Oceanic Sciences School of Physics Peking University Laboratory for Climate and Ocean-Atmosphere Studies Peking University

The planetary wave response to global warm ing with single forcing of greenhouse gases （GHGs） is investigated in this study by using a total of 11 model results that anticipated CMIP3 4XCO2 experiments. It is shown that the amplitudes of the planetary wave fluxes over Siberia, the Eastern North Pacific, and the North Atlantic decrease by approximately -10% to -30% in the warming context. In particular, the vertical wave flux over the Eastern North Pacific significantly decreases by -28.6%. The weakening of the planetary waves is partly associated with the decreased land-sea thermal contrast, which may be caused by the radiation effect of CO2 and the different surface heat capacities of land and sea. The present work provides a clear understanding of the re sponses of planetary waves to GHGs forcing.

关键词： planetary wave stationary-wave globalwarming 4~CO2 experiments

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

Incubation and development of corrosion in microstructures of low alloy steels under a thin liquid film of NaCl aqueous solution

引用

International Journal of Minerals,Metallurgy and Materials 2010年第6期17卷 748-755页

作者： wen-hua Zhang Shan-wu Yang jia Guo Zhi-yong Liu xin-lai He School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Electrochemical measurement, optical microscopy, and scanning electron microscopy were employed to investigate the corrosion behavior of some low alloy steels. The steels were held under a thin liquid film of 0.5wt% NaCl aqueous solution. It is found that the steels with the same chemical composition but different micmstructures exhibit obviously different corrosion behaviors. However, the corrosion behavior of the steels with different compositions but the same microstructnres may be similar in the present investigation. The corrosion rate of bainite is slower than that of ferrite and pearlite. The corrosion products of bainite are uniform and fine. The size of carbon-rich phases produces a great impact on the corrosion of the steels, whether in the initial stage or in the long tenn. It is easy to induce large pitting for carbon-rich phases with large size, which damages the compactness of the rust layer.

关键词： alloy steel microstructure atmospheric corrosion liquid films scanning electron microscope

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

An Innovative Coupled Common-Node Discrete Element Method-Smoothed Particle Hydrodynamics Model Developed with LS-DYNA and Its Applications

引用

China Ocean Engineering 2024年第3期38卷 467-482页

作者： SHEN Zhong-xiang WANG wen-qing XU Cheng-yue LUO jia-xin LIU Ren-wei School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China College of Harbor Coastal and Offshore EngineeringHohai UniversityNanjing 210098China

In this study,a common-node DEM-SPH coupling model based on the shared node method is proposed,and a fluid–structure coupling method using the common-node discrete element method-smoothed particle hydrodynamics(DS-SPH)method is developed using LS-DYNA *** DEM and SPH are established on the same node to create common-node DEM-SPH particles,allowing for fluid–structure *** simulations of various scenarios,including water entry of a rigid sphere,dam-break propagation over wet beds,impact on an ice plate floating on water and ice accumulation on offshore structures,are *** interaction between DS particles and SPH fluid and the crack generation mechanism and expansion characteristics of the ice plate under the interaction of structure and fluid are also *** results are compared with available data to verify the proposed coupling ***,the simulation results demonstrated that controlling the cutoff pressure of internal SPH particles could effectively control particle splashing during ice crushing failure.

关键词： common-node DEM-SPH fluid-structure interaction discrete element method smoothed particle hydrodynamics

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

Methylation profile of bovine Oct4 gene coding region in relation to three germ layers

引用

Journal of Integrative Agriculture 2016年第3期15卷 618-628页

作者： ZHOU xin-yu LIU Liang-liang jia wen-chao PAN Chuan-ying College of Life Sciences Northwest A&F University School of Computer Science & Engineering Jiangsu University of Science and Technology College of Animal Science and Technology Northwest A&F UniversityShaanxi Key Laboratory of Molecular Biology for Agriculture

Previous studies have shown that octamer-binding transcription factor 4（Oct4） plays a significant role in early embryonic development of mammalian animals, and different Oct4 expression levels induce multi-lineage differentiation which are regulated by DNA methylation. To explore the relationship between the methylation pattern of Oct4 gene exon 1 and embryonic development, in this work, five different tissues（heart, liver, lung, cerebrum and cerebellum） from three germ layers were chosen from low age（50–60 d） and advanced age（60–70 d） of fetal cattle and the differences between tissues or ages were analyzed, respectively. The result showed that the DNA methylation level of Oct4 gene exon 1 was significant different（P〈0.01） between any two of three germ layers in low age（〈60 d）, but kept steady of advanced age（P〉0.05）（〉60 d）, suggesting that 60-d post coital was an important boundary for embryonic development. In addition, in ectoderm（cerebrum and cerebellum）, there was no significant methylation difference of Oct4 gene exon 1 between low age and advanced age（P〉0.05）, but the result of endoderm（liver and lung） and mesoderm（heart） were on the contrary（P〈0.01）, which indicated the development of ectoderm was earlier than endoderm and mesoderm. The methylation differences from the 3rd, 5th and 9th Cp G-dinucleotide loci of Oct4 gene exon 1 were significantly different between each two of three germ layers（P〈0.05）, indicating that these three loci may have important influence on bovine embryonic development. This study showed that bovine germ layers differentiation was significantly related to the DNA methylation status of Oct4 gene exon 1. This work firstly identified the DNA methylation profile of bovine Oct4 gene exon 1 and its association with germ layers development in fetus and adult of cattle. Moreover, the work also provided epigenetic information for further studying bovine embryonic development and cellular reprogramming.

关键词： bovine DNA methylation octamer-binding transcription factor 4(Oct4) exon germ layer

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

CONVERGENCE OF AN IMMERSED INTERFACE UPWIND SCHEME FOR LINEAR ADVECTION EQUATIONS WITH PIECEWISE CONSTANT COEFFICIENTS Ⅱ: SOME RELATED BINOMIAL COEFFICIENT INEQUALITIES

引用

Journal of Computational Mathematics 2009年第4期27卷 474-483页

作者： xin wen LSEC ICMSEC Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

In this paper we give proof of three binomial coefficient inequalities. These inequalities are key ingredients in [wen and Jin, J. Comput. Math. 26, （2008）, 1-22] to establish the L^1-error estimates for the upwind difference scheme to the linear advection equations with a piecewise constant wave speed and a general interface condition, which were further used to establish the L^1-error estimates for a Hamiltonian-preserving scheme developed in [Jin and wen, Commun. Math. Sci. 3, （2005）, 285-315] to the Liouville equation with piecewise constant potentials [wen and Jin, SIAM J. Numer. Anal. 46, （2008）, 2688-2714].

关键词： Binomial coefficient Linear advection equations Immersed interface upwindscheme Piecewise constant coefficients Error estimates.

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

THE L1-ERROR ESTIMATES FOR A HAMILTONIAN-PRESERVING SCHEME FOR THE LIOUVILLE EQUATION WITH PIECEWISE CONSTANT POTENTIALS AND PERTURBED INITIAL DATA

引用

Journal of Computational Mathematics 2011年第1期29卷 26-48页

作者： xin wen LSEC ICMSEC Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

We study the Ll-error of a Hamiltonian-preserving scheme, developed in [19], for the Liouville equation with a piecewise constant potential in one space dimension when the initial data is given with perturbation errors. We extend the l1-stability analysis in [46] and apply the Ll-error estimates with exact initial data established in [45] for the same scheme. We prove that the scheme with the Dirichlet incoming boundary conditions and for a class of bounded initial data is Ll-convergent when the initial data is given with a wide class of perturbation errors, and derive the Ll-error bounds with explicit coefficients. The convergence rate of the scheme is shown to be less than the order of the initial perturbation error, matching with the fact that the perturbation solution can be l1-unstable.

关键词： Liouville equations Hamiltonian preserving schemes Piecewise constant po-tentials Error estimate Perturbed initial data Semiclassical limit.

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

HIGH ORDER NUMERICAL METHODS TO TWO DIMENSIONAL HEAVISIDE FUNCTION INTEGRALS

引用

Journal of Computational Mathematics 2011年第3期29卷 305-323页

作者： xin wen LSEC ICMSEC Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

In this paper we design and analyze a class of high order numerical methods to two dimensional Heaviside function integrals. Inspired by our high order numerical methods to two dimensional delta function integrals [19], the methods comprise approximating the mesh cell restrictions of the Heaviside function integral. In each mesh cell the two dimen- sional Heaviside function integral can be rewritten as a one dimensional ordinary integral with the integrand being a one dimensional Heaviside function integral which is smooth on several subsets of the integral interval. Thus the two dimensional Heaviside function inte- gral is approximated by applying standard one dimensional high order numerical quadra- tures and high order numerical methods to one dimensional Heaviside function integrals. We establish error estimates for the method which show that the method can achieve any desired accuracy by assigning the corresponding accuracy to the sub-algorithms. Numerical examples are presented showing that the in this paper achieve or exceed the expected second to fourth-order methods implemented accuracy.

关键词： Heaviside function integral High order numerical method Irregular domain.

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

Changes in soil organic carbon and aggregate stability after conversion to conservation tillage for seven years in the Huang-Huai-Hai Plain of China

引用

Journal of Integrative Agriculture 2015年第6期14卷 1202-1211页

作者： SHU xin ZHU An-ning ZHANG jia-bao YANG wen-liang xin Xiu-li ZHANG Xian-feng State Experimental Station of Agro-Ecosystem in Fengqiu State Key Laboratory of Soil and Sustainable Agriculture/Institute of Soil Science Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

Soil aggregate stability and organic carbon（OC） are regarded as effective indicators of soil structure and quality. A longterm field experiment was established in 2006 to examine the influence of tillage systems on soil aggregation and OC in a sandy loam soil in the Huang-Huai-Hai Plain of China. The study involved eight treatments： plowing every year with（TS） and without residue（T）, plowing every 2 years with（2TS） and without residue（2T）, plowing every 4 years with（4TS） and without residue（4T）, and no plowing with（NTS） and without residue（NT）. In 2013, soil samples were collected at depths of 0–5, 5–10 and 10–20 cm, and separated into three aggregate-size classes： macroaggregates（〉250 μm）, microaggregates（53–250 μm） and the silt＋clay fraction（〈53 μm） using wet sieving method. Soil parameters measured were water-stable aggregates, geometric mean diameter（GMD）, mean weight diameter（MWD） and OC concentrations in different aggregate-size fractions and in bulk soil. The tillage treatments significantly（P〈0.05） influenced soil aggregate stability and OC distribution. Higher MWD and GMD were observed in 2TS, 4TS and NTS as compared to T. With increasing soil depth, the amount of macroaggregates and MWD and GMD values were increased, while the proportions of microaggregates and the silt＋clay fraction were declined. The OC concentrations in different aggregate fractions at all soil depths followed the order of macroaggregates〉microaggregates〉silt＋clay fraction. In the 0–5 cm soil layer, concentrations of macroaggregateassociated OC in 2TS, 4TS and NTS were 14, 56 and 83% higher than for T, whereas T had the greatest concentration of OC associated with the silt＋clay fraction in the 10–20 cm layer. Soil OC concentrations under 4TS and NTS were significantly higher（P〈0.05） than that of T in the 0–10 cm layer. Residue retention promoted formation of macroaggregates, increased macroaggregate-associated OC concentrations and thus increased total soil OC stock. The macroaggregate-

关键词： aggregate conservation residue sequestration aggregation depths proportions declined wheat concluded

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：