检索结果-南通市图书馆

PREPARATION OF PEROVISKITE-TYPE La_(1-x)Sr_xMnO_3 AT LOW TEMPERATURE

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2001年第2期14卷 153-156页

作者： Z.B. Shao, L.J. Zhang, Y. Wang and Y. T. Gu (department of Chemistry, northeastern university, {2., china) (shenyang college of Education, shenyang 110015, china) Dept. of Chem. Northeastern Univ. Shenyang 110004 China

Peroviskite-type Lal-xSrxMnO3 (0≤x≤0.3) was prepared through the solgel process at low temperature (1100℃). The ethylene glycol and citric acid were used to make a sol-gel from an aqueous solution of lanthanum strontium and manganese nitrated. The particle-diameter distribution of powders is from 10 to 50urn, the mean particle size is about 35urn and the specific surface area is about 92.5 to 98.5m2.-1 .Peroviskite type ***3 was synthesized at 1100℃, and the electronic conductivity of La1-xSrxMnO3 is 104-105S.m-1 from room temperature to 1000℃.

关键词： sol-gel nanometer size peroviskite-type conductivity

Generating function approach to reliability analysis of structural systems

在线全文

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2009年第10期52卷 2849-2858页

作者： ZHOU JinYu1 & XIE LiYang2.1 Jiangsu Teacher’s university of Technology, Changzhou 2.3001, china 2.{2., shenyang 110004, china Jiangsu Teacher’s university of Technology Changzhou China northeastern university Shenyang China

The generating function approach is an important tool for performance assessment in multi-state systems. Aiming at strength reliability analysis of structural systems, generating function approach is introduced and developed. Static reliability models of statically determinate, indeterminate systems and fatigue reliability models are built by constructing special generating functions, which are used to describe probability distributions of strength (resistance), stress (load) and fatigue life, by defining composite operators of generating functions and performance structure functions thereof. When composition operators are executed, computational costs can be reduced by a big margin by means of collecting like terms. The results of theoretical analysis and numerical simulation show that the generating function approach can be widely used for probability modeling of large complex systems with hierarchical structures due to the unified form, compact expression, computer program realizability and high universality. Because the new method considers twin loads giving rise to component failure dependency, it can provide a theoretical reference and act as a powerful tool for static, dynamic reliability analysis in civil engineering structures and mechanical equipment systems with multi-mode damage coupling.

关键词： structure reliability generating function static strength failure fatigue failure failure dependence

Research on Solidification Structure of Billet for Bearing Steel

在线全文

学校读者我要写书评

暂无评论

稀有金属材料与工程 2011年第S3期40卷 220-223页

作者： Liu Chengjun, Wang Hongpo, Jiang Maofa northeastern university, shenyang 110004, {2. northeastern Univ Coll Mat & Met Shenyang 110004 Peoples R China

Secondary dendrite arm spacing (SDAS), which is an important parameter for solidification structure, has a significant effect on the level of segregation and the time for dispelling micro-segregation. The solidification structure of billets, poured under different drawing speeds for high-carbon chromium continuous casting and etched by saturated water solution of picric acid, was investigated by OLYMPUS BX51 optical microscope; and the indexes of carbon and sulfur segregation were also determined. It is concluded that the solidification structure consists of fine grain region, columnar region, cross dendrite region and central equiaxed grain region. In the columnar grain region, the SDAS at outer arc of billet is about 30 μm bigger than that of inner arc; the SDAS increases with the increasing drawing speed and the indexed of carbon and sulfur segregation change from positive segregation to the negative with the increasing SDAS. The SDAS can be used as an important parameter not only to establish reasonable secondary cooling system and drawing speed but also to judge the level of segregation in the unidirectional solidification region.

关键词： bearing steel solidification structure secondary dendrite arm spacing drawing speed segregation

A New Admissibility Condition of Discrete-time Singular Systems with Time-varying Delays

在线全文

学校读者我要写书评

暂无评论

International Journal of Automation and computing 2012年第5期9卷 480-486页

作者： Yong-Yun Shao 1,3 Xiao-Dong Liu 1,2.Xin Sun 3 Zhan Su 4 1 Transportation Management college, Dalian Maritime university, Dalian 11602., {2. 2.department of Mathematics, Dalian Maritime university, Dalian 11602., {2. 3 department of Computer and Mathematics Teaching, shenyang Normal university, shenyang 110034, {2. 4 Institute of Systems Science, northeastern university, {12., {2. Transportation Management college Dalian Maritime University Dalian China department of Computer and Mathematics Teaching Shenyang Normal University Shenyang China department of Mathematics Dalian Maritime University Dalian China Institute of Systems Science Northeastern University Shenyang China

This paper gives a novel delay-dependent admissibility condition of discrete-time singular systems with time-varying delays. For convenience, the time-varying delay is assumed to be the sum of delay lower bound and the integral multiples of a constant delay. Specially, if the constant delay is of unit length, the delay is an interval-like time-varying delay. The proposed admissibility condition is presented and expressed in terms of linear matrix inequality (LMI) by Lyapunov approach. Generally, the uncertainty of time-varying delay would lead to conservatism. In this paper, this critical issue is tackled by accurately estimating the time-varying delay. Consequently, the proposed admissibility condition is less conservative than the existing results, which is demonstrated by a numerical example.

关键词： Singular systems discrete-time delay-dependent admissibility time-varying delay

Biotransformation of indomethacin by the fungus Cunninghamella blakesleeana

在线全文

学校读者我要写书评

暂无评论

Acta Pharmacologica Sinica 2006年第8期27卷 1097-1102页

作者： Peng ZHANG~2.Li-hong LIN~4 Hai-hua HUANG~3 Hai-yan XU~2.Da-fang ZHONG~(2.3,5) ~2.aboratory of Drug Metabolism and Pharmacokinetics,shenyang Pharmaceutical university,shenyang 110016.china ~3Shanghai Institute of Materia Medica.Chinese Academy of sciences,Shanghai 2.12.3,china ~4department of Microbiology,shenyang Pharmaceutical university,shenyang 110016,china Laboratory of Drug Metabolism and Pharmacokinetics Shenyang Pharmaceutical University Shenyang 110016 China Shanghai Institute of Materia Medica Chinese Academy of Sciences Shanghai 201203 China department of Microbiology Shenyang Pharmaceutical University Shenyang 110016 China

Aim:To investigate the biotransformation of indomethacin,the first of the newernonsteroidal anti-inflammatory drugs,by filamentous fungus and to compare thesimilarities between microbial transformation and mammalian metabolism ***:Five strains of Cunninghamella（C elegans AS 3.156,C elegans AS 3.2.2.,C blakesleeana AS 3.153,C blakesleeana AS 3.910 andC echinulata AS 3.2.04）were screened for their ability to catalyze the biotransfor-mation of *** was partially metabolized by five strains ofCunninghamella,and C blakesleeana AS 3.910 was selected for *** metabolites produced by C blakesleeana AS 3.910 wereisolated using semi-preparative HPLC,and their structures were identified by acombination analysis of LC/MS~n and NMR *** three metabolites wereseparated and quantitatively assayed by liquid chromatography-ion trap ***:After 12. h of incubation with C blakesleeana AS 3.910,approximately 87.4% of indomethacin was metabolized to three metabolites:O-desmethylindomethacin（DMI,M1,67.2.）,N-deschlorobenzoylindomethacin（DBI,M2.13.3%）and O-desmethyl-N-deschlorobenzoylindomethacin（DMBI,M3,6.9%）.Three phase I metabolites of indomethacin produced by C blakesleeanaAS 3.910 were identical to those obtained in ***:C blakesleeanacould be a useful tool for generating the mammalian phase I metabolites ofindomethacin.

关键词： indomethacin microbial transformation Cunninghamella blakesleeana liquid chromatography mass spectrometry

Finite frequency H∞ filtering for uncertain discrete-time switched linear systems

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2009年第11期19卷 1625-1633页

作者： Dawei Ding~(a,*),Guanghong Yang~(a,b) a college of Information Science and Engineering,northeastern university,{2.,china b Key Laboratory of Integrated Automation of Process Industry,Ministry of Education,northeastern university,{2.,china college of Information Science and Engineering Northeastern University Shenyang 110004 China Key Laboratory of Integrated Automation of Process Industry Ministry of Education Northeastern University Shenyang 110004 China

This paper is concerned with the problem of robust H∞filtering for discrete-time switched linear systems with polytopic uncertainties in the finite frequency *** on the generalized Kalman-Yakubovich-Popov(GKYP) lemma and switched parameter-dependent Lyapunov functions,a switched full-order filter is designed such that the corresponding filtering error system is asymptotically stable and satisfies a prescribed finite frequency H∞performance *** with the existing full frequency approaches,the proposed finite frequency one receives better results for the cases in which the frequency ranges of noises are known.A numerical example is given to illustrate the effectiveness of the proposed method.

关键词： Switched systems Filtering Finite frequency GKYP lemma Linear matrix inequalities(LMIs)

Continuously extending extrusion forming of semisolid A2.17 alloy by SRS process

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2002年第4期21卷 271-277页

作者： GUANRenguo LIUXianghua 等 MaterialandMetallurgySchool NortheastemUniversityShenyang110004China StateKeyLaboratoryofRollingandAutomation NortheasternUniversityShenyang110004China

A self-made single-roll stirring (SRS) machine was used to manufacturesemisolid A2.17 alloy, the mechanism of A2.17 alloy formation was investigated. It was shown thatA2.17 dendrites growing on the rough roll surface are crashed into fragments by the roll, which moveand grow freely then contribute the formation of finer spherical microstruc-ture. When casting at710-750℃, fine and homogeneous spherical or elliptical grains of A2.17 alloy were *** forming mould has been designed and was installed at the exit of roll-shoe gap. A2.17alloy was formed by extending continuously at the semisolid state on SRS machine. Throughcontrolling pouring temperature, semisolid forming and extending extrusion was combined organically.A2.17 product with fine surface and rectangular transection of 14 mm x 2. mm was obtained. Bycontrast to the national standard, the fracture strength and elongation of A2.17 products producedfrom extending semisolid extrusion have been improved with an increase of 100 MPa and 2.%,respectively.

关键词： semisolid Al base alloy extending forming SRS process microstructure property

Bipolar charged aerosol agglomeration and collection by a two-zone agglomerator

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental sciences 2001年第3期13卷 276-279页

作者： XIANG Xiao dong 1, CHEN Bao zhi 1, COLBECK I 2.(1. School of Resource and Civil Engineering, northeastern university, shenyang 110006, {2.. 2. Institute for Environmental Research, department of Biological and Chemical sciences, university of Es School of Resource and Civil Engineering Northeastem University Shenyang 110006 China. E-mail:[email protected]mail. neu. cn Institute for Environmental Research Department of Biological and Chemical Sciences University of Essex Colchester CO4 3SQ UK

In older to collect fine particles more efficiently, a new-type electrostatic agglomerator with two zones was developed. The distinguishing feature of this electrostatic agglomerator is that the particles are bipolarly charged and coagulated in the same alternating electric field simultaneously. The silica flour with 2.fun mass median diameter and the smoke from burning wood powder were used as test aerosol. The comparison experimental results have shown that when the mean electric field is 4 kV/cm the collection efficiency of the new electrostatic agglomerator was 98.2. for silica flour and 67.4% for wood powder smoke, Under the same experimental condition. the collection efficiency of the electrostatic agglomerator with three zones was 97.4% for collecting silica flour and the collection efficiency of the electrostatic precipitator was 56.3% for wood powder smoke.

关键词： charged particle agglomeration alternating electric field electrostatic agglomerator (EA) electrostatic precipitator (ESP) collection efficiency

Adaptive synchronization of neural networks with different attractors

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第6期17卷 687-695页

作者： Zhang Huaguang1, Guan Huanxin1 and Wang Zhanshan1,2.1. School of Information Science and Engineering, northeastern university, shenyang 110004, {2. 2. School of Information Science and Engineering, shenyang Ligong university, shenyang 110168, {2.) School of Information Science and Engineering Northeastern University Shenyang 110004 China School of Information Science and Engineering Shenyang Ligong University Shenyang 110168 China

This paper aims to present an adaptive control scheme for the synchronization of two classes of uncertain neural networks with different attractors. A new sufficient condition for the global synchronization of two kinds of neural networks with different attractors is derived. The proposed control method is efficient and easy to be implemented. Numerical simulation is used to show the effectiveness of the obtained result.

关键词： neural networks attractor adaptive synchronization linear matrix inequality.