检索结果-南通市图书馆

PEG-g-poly(aspartamide-co-N,N-dimethylethylenediamino aspartamide):Synthesis,characterization and its application as a drug delivery system

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10期19卷 1305-1310页

作者： Dong Yang,Xiaohong Zhang,Li Yuan,Jianhua Hu key laboratory of Molecular engineering of Polymers(ministry of education),laboratory of advanced materials,department of Macromolecular science,Fudan university,Shanghai 200433,china key laboratory of Molecular engineering of Polymers (ministry of education) Laboratory of Advanced Materials Department of Macromolecular Science Fudan University Shanghai 200433 China

PEG-g-poly(aspartamide-co-N,N-dimethylethylenediamino aspartamide)(PEG-DMEDA-PASP) was synthesized by two-step ring-opening reactions of polysuccinimide(PSI) with a-methoxy-x-amino-poly(ethylene glycol) and N,*** polymer structure was confirmed by 1H NMR and *** resultant PEG-DMEDA-PASP with ammonium glycyrrhizinate(AMG) could form polymeric micelles in aqueous *** results of transmission electron microscopy(TEM) and dynamic light scattering(DLS) measurements revealed that these polymeric micelles were spherical particles with a narrow diameter distribution and that their average diameter was ca.70 *** polymeric micelles had high-loading capacity(58%) and encapsulation efficiency(70%) for *** results of in vitro release experiments showed that these polymeric micelles possessed sustained-release effects,with a release rate of 25% within 3 h and 90% within 24 h.

关键词： PEG-g-poly(aspartamide-co-N,N-dimethylethylenediamino aspartamide) Polymeric micelle Drug delivery system Ammonium glycyrrhizinate

Full-scale experimental research on fire fume refluence of sloped long and large curved tunnel

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Technological sciences) 2011年第S1期54卷 89-94页

作者： ZHONG MaoHua 1,SHI CongLing 1,HE Li 1,SHI JieHong 1 & FU TaiRan 2 1 china Academy of Safety science and Technology,beijing 100012,china 2 key laboratory for Thermal science and Power engineering of ministry of education,department of Thermal engineering,tsinghua university,beijing 100084,china china Academy of Safety science and Technology Beijing China key laboratory for Thermal science and Power engineering of ministry of education Department of Thermal Engineering Tsinghua University Beijing China

A full-scale experimental research is conducted on the fire fume refluence of a sloped long and large curved tunnel in the underground plant of a hydraulic and hydropower engineering project under three different fire *** a result,the eddy effect and pattern of the fire fume flow in the tunnel in case of fire is discovered and the refluence of the fume layers in case of fire is *** analysis of the temperature measurement resulted in the course of the experiment,the main characteristics and performance of the fire fume refluence are discussed under the three different fire powers.

关键词： large and long tunnel fire fume refluence experiment

Effect of TRT process on GFA,mechanical properties and microstructure of Zr-based bulk metallic glass

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:materials International 2011年第1期21卷 53-58页

作者： Guang-qiao LIU~1,Sheng-zhong KOU~(1,2),Chun-yan LI~1,Yan-chun ZHAO~1,Hong-li SUO~2 1.State key laboratory of Gansu advanced Non-ferrous Metal materials, Lanzhou university of Technology,Lanzhou 730050,china 2.The key laboratory of advanced Functional materials(ministry of education), beijing university of Technology,beijing 100022,china State key laboratory of Gansu advanced Non-ferrous Metal materials Lanzhou University of Technology Lanzhou 730050 China The key laboratory of advanced Functional materials (ministry of education) Beijing University of Technology Beijing 100022 China

Series of rod samples of Zr55Al10Ni5Cu30 alloy were prepared by magnetic suspend melting and copper mold suction casting *** effect of thermal rate treatment（TRT） process on glass forming ability（GFA）,mechanical properties and microstructure of Zr-based bulk metallic glass were *** shows that GAF,mechanical properties and microstructure of as-cast Zr55Al10Ni5Cu30 BMGs alloy to a large extent is related to TRT *** and thermal stability of as-cast Zr55Al10Ni5Cu30 alloy increase when overheating temperature *** liquid region△Txand parameterγincrease from 73 K to 89 K,from 0.413 to 0.417,respectively,when casting voltage increases from 7 kV to 10 *** a threshold overheating temperature is found for the fully amorphous structure,below which it may have an intersection with the crystallization *** is found that the compressive strength increases and the compressive plasticity slightly decreases when overheating temperature ***,the compressive strength and the compressive plasticity simultaneously increase to 1.91 MPa and 2%when casting voltage increases to 10 kV.

关键词： bulk metallic glass glass forming ability(GFA) mechanical properties thermal rate treatment(TRT) process microstructure

Relationship between Ballistic Coefficient and Static Mechanical Properties for Armor materials

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of university of science and Technology beijing 2001年第1期8卷 53-54页

作者： Junpin Lin, Yong Zhang, Zhi Lin, Guoliang Chen The State key laboratory for advanced Metal materials, university of science and Technology beijing, beijing 100083, china State key Lab. advanced Metal Mat. Univ. of Sci. and Technology Beijing Beijing 100083 China

The relationship between the ballistic coefficient and the static mechanical properties of armor materials was studied. The results show that the ballistic coefficient is determined by the strength, hardness and the toughness of materials. According to the Martel rule, the equation of the relationship between ballistic coefficient and static mechanical properties satisfies the following formula: W-s=M(1+NK1C/rho )Hr. From the mixture law of composite, the prerequisite, for which ballistic coefficient has maximum to reinforcement volume fraction, is obtained by the following equation: dWs/Df=b(K(1)rho (0)-K(0)rho (1))H/rho (2)+(a+bK/rho)(H-1-H-0).

关键词： armor materials ballistic coefficient toughness

Precipitation of α Phase in the Massive and Feathery Structures in TiAl Alloys during Aging in the Single α Field

在线全文

学校读者我要写书评

暂无评论

Journal of materials science & Technology 1999年第5期15卷 469-472页

作者： Weijun ZHANG and Glloliang CHEN(State key laboratory for advanced Metals and materials, university of science and Technology beijing, beijing 100083, china To whom correspondence should be addressed ) State key laboratory for advanced Metals and materials University of Science and Technology Beijing Beijing 100083 China

Precipitation of α-phase in massive and feathery microstructures was studied during aging in the single α field. It was found that the α-phase mainly precipitated along the γ-plate interfaces as laths in the feathery structure, while it nucleated at various sites in the massive structure in the form of particles and dominantly as plates. Precipitation of α-plates in the massive structure occurred by the difFusional ledge mechanism. The γm→α reaction proceeded by the growth of previously nucleated α-precipitates, and chiefly by the development of new α-plates

关键词： TiAl Precipitation of Field Phase in the Massive and Feathery Structures in TiAl Alloys during Aging in the Single

INTERPHASE　STRESS　CORROSION　CRACKING　OF　ALLOY　Ti－24Al－11Nb　IN　METHANOL　SOLUTION

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1996年第2期9卷 121-128页

作者： ZHANG Yue CHU Wuyang XIAO Jimei(department of materials Physics,university of science and Technology beijing,beijing 100083,china) OUYANG Shixi YUAN Runzhang(State key laboratory for Synthesis and Processing of advanced materials.Wuhan university of Techn Univ of science and Technology Beijing Beijing China

For alloy Ti-24Al-11Nb,stress corrosion cracking(SCC) in methanol solution and hydrogen induced cracking(HIC) during dynamic charging at room temperature have been *** has shown that the normalised threshold stress intensities of SCC failure for various microstructures are KISCC/KC =0.53 0.69 and the threshold value for SCC arresting KISCC/ KIC=*** threshold values of HIC during dynamic charging are close to that of SCC,but da/dt or fracture time of HIC is one to three orders of magnitude smaller or longer than that of SCC,*** surface for HIC is also different from that for *** the Ti-24Al-Nb alloy-methanol systein,a kind of inierphase SCC has been found For the microstructures resulting from furnace cooling,SCC initiated and propagated preferentially along theα2/βinterphase boundaries,displaying the microstructure on the fracture surface of ***,there is no interphase SCC for the microstructure resulting from air cooling.

关键词： Ti-24Al-11Nb,hydrogen induced cracking,interphase stress corrosion cracking methanol

Capability description and discovery of Internetware entity

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2010年第4期53卷 685-703页

作者： WANG PuWei1*, JIN Zhi2,3* & LIU HongYan4 1key laboratory of Data engineering and Knowledge engineering of the ministry of education, Renmin university of china, beijing 100872, china 2key laboratory of High Confidence Software Technologies of the ministry of education, Peking university, beijing 100871, china 3Academy of Mathematics and System sciences, Chinese Academy of sciences, beijing 100190, china 4department of Management science and engineering, tsinghua university, beijing 100084, china key laboratory of Data engineering and Knowledge engineering of the ministry of education Renmin University of China Beijing China key laboratory of High Confidence Software Technologies of the ministry of education Peking University Beijing China Academy of Mathematics and System sciences Chinese Academy of Sciences Beijing China department of Management science and engineering Tsinghua University Beijing China

Internetware can be formed through aggregation of Internetware entities bottom-up to satisfy the user's requirements. In the process, capability description of Internetware entity plays an important role. This paper proposes a capability description of Internetware entity based on environment ontology. The environment ontology includes environment entities and possible interactions with the environment entities in a particular domain. Tree-like hierarchical state machines are also included in the ontology to describe domain life-cycle of the environment entities. On the basis of the ideas, the capability of Internetware entity is embodied by interacting with environment entities and the changes of the environment entities during the interactions. Finally, this paper describes the matchmaking between capability descriptions of Internetware entities to support the discovery of Internetware entity. An example of online education course is given to illustrate the ideas.

关键词： Internetware capability description domain environment ontology tree-like hierarchical state machine

Preparation of MWNTs/Al_2O_3 composites and their mechanical and electrical properties

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Technological sciences) 2005年第6期48卷 622-631页

作者： FAN Jinpeng1,2, ZHAO Daqing1,2, XU Zening1,2 & WU Minsheng1,2 1. department of Mechanical engineering, tsinghua university, beijing 100084, china 2. key laboratory for advanced Manufacturing by materials Processing Technology, tsinghua university, beijing 100084, china department of Mechanical engineering Tsinghua University Beijing China key laboratory for advanced Manufacturing by materials Processing Technology Tsinghua University Beijing China

The mechanical and electrical properties of MWNTs/Al2O3 composite prepared fabricated by hot pressing are investigated. The relation between properties and microstructure of composites is also discussed. With 4wt% MWNTs as reinforcement, the fracture toughness of composite obtained reaches 5.55 MPa·m1/2, which is 80% higher than that of pure Al2O3 obtained in the same conditions. The main toughening mechanism is CNTs’ pinning alumina grain boundaries, and the pullout of CNTs takes effect also. Through adding 2wt% MWNTs and altering the mix method, the fracture toughness of the composite obtained is 3.97 MPa·m1/2. Furthermore, the electrical resistivity is as low as 8.4×10?3 ?·m, decreasing by 14 orders of magnitude compared with pure alumina ceramics. The function of CNTs in composite is related to the distribution state of CNTs in composite, and the distribution state of CNTs in matrix is dependent on preparation procedures.

关键词： MWNTs, alumina, composite, fracture toughness, electrical properties.

Sediment transport capacity of hyperconcentrated flow

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2008年第8期51卷 961-975页

作者： SHU AnPing1,2 & FEI XiangJun2 1 School of Environment & key laboratory of Water and Sediment sciences,ministry of education,beijing Normal university,beijing 100875,china 2 State key laboratory of Hydroscience and engineering,tsinghua university,beijing 100084,china School of Environment & key laboratory of Water and Sediment sciences Ministry of Education Beijing Normal University Beijing China State key laboratory of Hydroscience and engineering Tsinghua University Beijing China

As one of the most important components of river mechanics,sediment transport capacity of sediment-laden flows has attracted much attention from many researchers working on river mechanics and hydraulic engineering. Based on the time-averaged equation for a turbulent energy equilibrium in solid and liquid two-phase flow,an expression for the efficiency coefficient of suspended load movement was derived for the two-dimensional,steady,uniform,fully-developed turbulent flow. A new structural expression of sediment transport capacity was achieved. Using 115 runs of flume experimental data,which were obtained through two kinds of sediment transport experiments in the state of equilibrium,in combination with the basic rheological and sediment transporting characteristics of hyperconcentrated flow,the main parameters in the structural expression of sediment transport capacity were calibrated,and a new formula of sediment transport capacity for hyperconcentrated flow was developed. A large amount of field data from the Yellow River,Wuding River,and Yangtze River,etc. were adopted to verify the new formula and good agreement was obtained. These results above contribute to an improved theoretical system of river mechanics and a reliable tool for management of rivers carrying high concentration of sediments.

关键词： hyperconcentrated flow turbulent energy equilibrium efficiency coefficient sediment transport capacity