检索结果-南通市图书馆

NUMERICAL SIMULATION OF BATOID LOCOMOTION

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2011年第5期23卷 594-600页

作者： CHEN Wei-shan WU Zhi-jun LIU jun-kao shi Sheng-jun ZHOU yang State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150001 China

The hydrodynamics of batoid swimming motions is investigated using the three-dimensional simulation of a self-propelled body in still water. The kinematics of batoid swimming is characterized by large amplitude undulations of the pectoral fins while the middle part of the body remains straight. The majority of the thrust is generated by pectoral fins. Linear and quadratic amplitude variations are used for the pectoral fins in analyzing the locomotion of the batoid. Navier-Stokes equations are used to solve the unsteady fluid flow. A user defined function and a dynamic mesh method are applied to track the batoid locomotion. The mean swimming velocities of 1.6 BL/s and 1.3 BL/s are achieved, respectively, with thrust coefficients of 0.13 in and 0.095 in the dynamical simulation, where BL/s is the body length per second. The maximum propulsive efficiency 19% is achieved when the frequency of the undulation is 2.2 Hz in both amplitude variations.

关键词： batoid fish undulation pectoral fin dynamical simulation

MiR-24-3p Attenuates Doxorubicin-induced Cardiotoxicity via the Nrf2 Pathway in Mice

在线全文

学校读者我要写书评

暂无评论

Current Medical Science 2022年第1期42卷 48-55页

作者： Di FAN Hong-bin CHEN Yan LENG shi-jun yang Department of Cardiology Renmin Hospital of Wuhan UniversityWuhan 430060China Department of Cardiology Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430060China Department of Pulmonary and Critical Care Medicine Renmin Hospital of Wuhan UniversityWuhan 430060China Department of Anesthesiology Renmin Hospital of Wuhan UniversityWuhan 430060China.

Objective:The nuclear factor erythroid 2(NFE2)-related factor 2(Nrf2)is associated with doxorubicin(DOX)-induced cardiac *** has been reported that microRNA-24-3p(miR-24-3p)may regulate the Keapl by mRNA degradation,whereas Keapl can suppress the activation of ***,the role of miR-24-3p in DOX-related cardiotoxicity remains unclear.

关键词： miR-24-3p Ros doxorubicin nuclear factor erythroid 2-related factor 2 apoptosis

Development of Glass Ceramics Made From Ferrous Tailings and Slag in China

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

Journal of Iron and Steel Research International 2007年第2期14卷 73-78页

作者： LIU Cheng-jun shi Pei-yang ZHANG Da-yong JIANG Mao-fa School of Materials and Metallurgy Northeastern University Shenyang 110004 Liaoning China

A great amount of ferrous tailings and slag cause severe damage to the ecological environment, which must be reclaimed and utilized. The composition, type, and characteristics of ferrous tailings and slag in China were introduced. The research status and the application outlook of glass ceramics made from ferrous tailings and slag were discussed. Glass ceramics made from ferrous tailings and slag can be applied to various fields, and it will be environmentally conscious materials in the 21st century.

关键词： glass ceramics ferrous tailings slag

Effects of Heat Treatment on Dimension Stability of Larch Pallet Decks

在线全文

学校读者我要写书评

暂无评论

Journal of Harbin Institute of Technology(New Series) 2013年第3期20卷 75-80页

作者： Xue-Chun yang Bing Wang Jin-Zhuo Wu Xiao-Qi Xing shi-jun yang College of Engineering and Technology Northeast Forestry University

The useful life of wooden pallets is lower because of the defects in lumbers. The quality of lumber can be significantly enhanced by heat treatment. In this paper,the larch pallet decks samples were heat-treated under the conditions of different time and temperatures. The quantity of water uptake has reduced 16. 8% under the condition of 250 ℃ for 150 min. The resistance of water absorption efficiency increases 165. 34% under the condition of 175 ℃ for 90 min. The anti-shrink efficiency increases 72. 08% under the condition of 250 ℃ for 90min. The results showed that the dimension stability of larch panels can be improved by heat treatment. The condition of 250 ℃ for 180 min is the best heat treating condition to improve the dimension stability.

关键词： larch pallet heat treatment resistance of water absorption efficiency anti-shrink efficiency dimension stability

Influence of alloy ingredients on mechanical properties of ternary boride hard alloy clad materials

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2004年第Z1期14卷 482-486页

作者： LIU Fu-tian SONG shi-xue yang jun-ru HUANG Wei-ling HUANG Chuan-zhen CHENG Xin LI Zhao-qian School of Materials Science and Engineering Ji''nan University Ji''nan 250022 China School of Mechanical Engineering Shandong University Ji''nan 250061 China Techinal Center Ji''nan Iron & Steel Group Corporation Ji''nan 250101 China School of Materials Science and Engineering Ji''nan University Ji''nan 250022 China School of Mechanical Engineering Shandong University Ji''nan 250061 China School of Mechanical Engineering Shandong University Ji''nan 250061 China School of Mechanical Engineering Shandong University Ji''nan 250061 China School of Materials Science and Engineering Ji''nan University Ji''nan 250022 China School of Mechanical Engineering Shandong University Ji''nan 250061 China

Using Mo, B-Fe alloy and Fe powders as raw materials, and adding C, Cr and Ni ingredients, respectively, or C, Cr and Ni mixed powders, ternary boride hard alloy clad materials was prepared on Q235 steel substrate by means of in-situ reaction and vacuum liquid phase sintering technology. The influence of alloy ingredients on the mechanical properties of ternary boride hard alloy clad materials was investigated. The results indicate that a mixture of 0.8% C, 5% Cr and 2% Ni ingredients gives a ternary boride hard alloy clad material with optimal mechanical properties, such as high transverse rupture strength, high hardness and good wear resistance.

关键词： hard alloy cladding liquid phase sintering alloying ingredient transverse rupture strength hardness wear resistance

Glycyrrhizinate reduces portal hypertension in isolated perfused rat livers with chronic hepatitis

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

World Journal of Gastroenterology 2013年第36期19卷 6069-6076页

作者： Xin Zhao Bo Deng Xue-Yan Xu shi-jun yang Tao Zhang Yi-jun Song Xiao-Ting Liu Yue-Qi Wang Da-Yong Cai Institute of Medicinal Plant Development Chinese Academy of Medical Sciences Peking Union Medical College School of Basic Medicine Beijing University of Chinese Medicine

AIM:To investigate the effects of diammonium glycyrrhizinate(Gly)on portal hypertension(PHT)in isolated portal perfused rat liver(IPPRL)with carbon tetrachloride(CCl4)-induced chronic ***:PHT model was replicated with CCl4 in rats for 84 *** was identified by measuring the ascetic amounts,hepatic function,portal pressure in vivo,splenic index,and pathological *** nitric oxide synthase(iNOS)in liver was assessed by *** were performed at d0,d28,d56,and *** phenylephrine-induced constriction,Gly was geometrically used to reduce *** action was expressed as median effective concentration(EC50)and area under the curve(AUC).Underlying mechanism was exploited by linear correlation between AUC values of Gly and existed iNOS in portal ***:PHT model was confirmed with ascites,splenomegaly,serum biomarkers of hepatic injury,and elevated portal *** findings had shown normal hepatic structure at d0,degenerations at d28,fibrosis at d56,cirrhosis at d84in PHT *** lobule ratios decreased and collagen ratios increased progressively along with PHT *** does dose-dependently reduce PHT in IPPRLs with CCl4-induced chronic *** potencies were increased gradually along with PHT development,characterized with its EC50at 2.80×10-10,3.03×10-11,3.77×10-11and 4.65×10-11mol/L at d0,d28,d56and d84,*** iNOS was located at hepatocyte at d0,stellate cells at d28,stellate cells and macrophages at d56,and macrophages in portal triads at *** infiltrated more into portal triads and expressed more iNOS along with PHT *** values of Gly were positively correlated with existed iNOS levels in portal ***:Gly reduces indirectly PHT in IPPRL with CCl4-induced chronic *** underlying mechanisms may relate to rescue NO bioavailability from macrophage-derived peroxynitrite in portal triads.

关键词： Chronic hepatitis Portal hypertension Isolated portal perfused rat liver Diammonium glycyrrhizinate Inducible nitric oxide synthase

URBANIZATION AND ITS IMPACTS ON WATER ENVIRONMENT IN TUMEN RIVER BASIN

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

Chinese Geographical Science 2002年第3期12卷 273-281页

作者： WANG shi-jun,WANG Dan,yang Xiang-h ua(College of Urban and Environmental Sciences,Northeast Normal University,Changchun 130024,P.R.China) College of Urban and Environmental Sciences Northeast Normal University Changchun P. R. China

The trans-boundary scope of the Tume n River Basin(TRB)going through China,Russia and DPRK has been defined,and on the basis of this,status of urbanization and its impacts on water environment in recent 20years in TRB have been *** n in TRB can be characterized as:1)There is medium level of overall urbanization in *** distance still exists compared with developed *** it is lower than the average urbanization level of Russia and higher than that o f China.2)There is unbalanced distribution of urbanization development in *** in China part owns the c haracter of low starting point and hi gh-speed *** Russia part,charac-ter of urbanization can be described as high starting point and stable *** DPRK part,urbanizatio n level is low,and motive power lacks.3)Due to large population,in China part there is broader region urbanized,larger radius and higher frequency of human activities,which lead to heavier pressure on ***,the paper has point-ed that impacts of urbanization on wa ter environment are as follows:1)Urban population growth and industr y develop-ment increase the demand for freshwa ter,and also exacerbate the contrad iction between limited water supply and increas-ing freshwater demand.2)Urban infrastructure doesn’t match with urban productive function especially treatment facili-ties,which results in the pollution of the Tumen River.3)The pollution situation in the Tumen River got peak point in1995,and presently,such situation has been improved in great scale,due to effective interventions ***,there still exist 2enterprises that are urgent to be ***,pollution of municipal sewage will become more and more apparent.4)The influence of urbanization on soil is mainly caused by industrial effl uent and slag,and pollut-ed water *** and water l oss has also been a serious problem caused by urbanization.5)Urbanization results in the decrease of wet

关键词： tumen river basin (TRB) urbanization water environment

在线全文

学校读者我要写书评

暂无评论

一种新的用于跨领域推荐的迁移学习模型

计算机学报 2017年第10期40卷 2367-2380页

作者：王俊李石君杨莎金红余伟软件工程国家重点实验室武汉大学计算机学院武汉430072 汉口学院计算机科学与技术学院武汉430212

协同过滤是一种简单常用的推荐方法,但是当目标数据非常稀疏时,其性能会严重退化,借助与目标数据跨域关联的辅助数据进行跨领域推荐是解决此问题的一种有效途径.已有的跨领域推荐模型大多假设不同领域完全共享一个评分模式,忽略了领域... 详细信息

协同过滤是一种简单常用的推荐方法,但是当目标数据非常稀疏时,其性能会严重退化,借助与目标数据跨域关联的辅助数据进行跨领域推荐是解决此问题的一种有效途径.已有的跨领域推荐模型大多假设不同领域完全共享一个评分模式,忽略了领域特有评分模式,可能导致推荐性能退化.此外,许多模型基于单一桥梁迁移跨领域信息,正迁移不足.特别是在考虑领域特有被评分模式的前提下,据作者所知目前还没有模型利用项目的共享被评分模式进行跨领域推荐.因此,该文提出一种新的三元桥迁移学习模型,用于跨领域推荐.首先通过评分矩阵的集合分解提取用户的潜在因子和共享评分模式,以及项目的潜在因子和共享被评分模式,在此过程中考虑了领域特有模式,并对潜在因子施加相似性约束;然后利用潜在因子中的聚类信息构造邻接图;最后通过用户端和项目端的基于共享模式、潜在因子和邻接图的三元桥迁移学习联合预测缺失评分.在三个公开的真实数据集上进行的大量实验表明,该模型的推荐精度优于一些目前最先进的推荐模型.

关键词：迁移学习推荐协同过滤跨领域稀疏矩阵分解

CHEMISTRY OF 1,2,4—TRIAZINES XIX THE ANOMALOUS SUBSTITUTED BENZENE SULFONATION AND PROPERTIES OF NUCLEOPHILIC ATTACK ON 6-CARBON OF 3-METHYLTHIO-5-HYDROXY-1,2,4-TRIAZINE

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1993年第9期4卷 771-774页

作者： Mei HAN Xu Ling shi Zhen jun yang Meng Shen CAI Tie Ming CHENG School of Pharmaceutical Sciences,Beijing Medical University,Beijing 100083

3-Methylthio-5-hydroxy-1,2,4-triazine(1c)reacted with substituted benzenesulfonyl chloride to give 3-methylthio-5-oxy-1,2,4-triazin-6-yl pyridinium betaine(4)in anhydrous *** when NaOH/H_2O/CH_3COCH_3 or NaOH/CH_3OH were used as reactant and solvent,3-methylthio-4-substituted benzenesulfonyl-5-oxo-6-hydroxy-1,4,5,6-tetrahydro-1,2,4-triazine(6)or 1-tosyl-3-methylthio-5-oxo-6-methyloxy-1,4,5,6-tetrahydro-1,2,4-triazine(7)was obtained *** above reactions show anomalous properties of nucleophilic attack on 6-carbon in 1,2,4-triazine ring.

关键词： NaOH CHEMISTRY OF 1,2,4 TRIAZINES XIX THE ANOMALOUS SUBSTITUTED BENZENE SULFONATION AND PROPERTIES OF NUCLEOPHILIC ATTACK ON 6-CARBON OF 3-METHYLTHIO-5-HYDROXY-1,2,4-TRIAZINE