检索结果-南通市图书馆

Influence of intermediate annealing on the microstructure and texture of Ni-9.3at%W substrates

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2014年第2期21卷 162-168页

作者： Jia-nan Liu Wei Liu Guo-yi Tang ru-fei Zhu Advanced Materials Institute and Cleaner Production Key Laboratory Graduate School at Shenzhen Tsinghua University Key Laboratory of Advanced Materials Department of Materials Science and Engineering Tsinghua University

The effects of intermediate annealing （IA） on the microstructure and texture of Ni-9.3at%W substrates have been investigated by using electron backscattering diffraction and X-ray diffraction. Results suggest that IA can optimize the homogeneity of deformation micro-structure. Higher IA temperatures （without undergoing recrystallization during IA） will increase the copper-type components of deformation texture and improve the content of cube texture after recrystallization. Sharp cube texture （97.2%） can be obtained at the optimum IA tem-perature of 650°C. The mechanism underlying the transition of deformation texture can be interpreted as that IA increases the dislocation slipping ability and suppresses the twinning deformation of Copper orientation in the subsequent rolling process. The observed strengthening of cube texture as a result of IA treatment is presumably attributed to the reduction of noncube nucleation and the optimization of preferential growth surrounding the cube nuclei.

关键词： nickel tungsten alloys annealing textures rolling

Rapid Self-healing and Strong Adhesive Elastomer via Supramolecular Aggregates from Core-shell Micelles of Silicon Hydroxyl-functionalized cis-Polybutadiene

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2023年第1期41卷 84-94页

作者： ying-ying Zheng Han Zhu yi Tan feng-yi-Qi Liu yi-Xian Wu State Key Laboratory of Chemical Resource Engineering Beijing Advanced innovation Center for Soft Matter Science and EngineeringBeijing University of Chemical TechnologyBeijing100029China

Liquid trimethoxy silane-functionalized cis-polybutadiene(cis-PB-Si(OMe)3),possessing number-average molecular weights of cis-PB segments(Mn,PB)ranging from 1800 g/mol to 5400 g/mol,with cis-1,4 content of ca.80%and high functionality(>96%)could be synthesized by coordination copolymerization of living cis-PB chain ends with ethenyltrimethoxy-silane with neodymium-based catalytic *** silicon hydroxyl-functionalized cis-polybutadiene(cis-PB-Si(OH)_(3))-based micelles in water have been achieved by in situ hydrolysis of cis-PB-Si(OMe)_(3)in hexane/water mixture(pH=6.8)at 70℃and by sequential removal of residue *** size of the above micelles with soft elastic cis-PB cores could be remarkably enlarged by loading SiO_(2)nanoparticles on their surfaces via hydrogen bonding *** supramolecular long chain aggregates or networks formed by hydrogen bonding interaction and possible O—Si—O chemical bonds between cis-PB-Si(OH)3-based micellar surfaces had relatively large size and thus precipitated from water after several months of storage,leading to production of cis-PB-Si(OH)_(3)solid elastomer with extremely low T_(g)at−107.0℃.The left cis-PB-Si(OH)_(3)-based micelles in water with relatively small size gradually formed the water-insoluble cis-PB-Si(OH)_(3)-based supramolecular aggregates or *** cis-PB-Si(OH)_(3)-based supramolecular elastomer exhibited excellent self-healing property within 60 s at 25℃.The elastomer(20 mg)in a joint of 25 mm×30 mm(2.7 mg/cm^(2))provided very strong adhesion for two pieces of glass and the bound glass keep unchanged at room temperature for 98 h even hung with 100 g of steel column *** cis-PB-Si(OH)3-based supramolecular elastomer would have potential applications in adhesives,self-healing materials,damping materials and elastic materials.

关键词： Amphiphilicity Polybutadiene Core-shell micelles Supramolecular aggregates

Mesoporous Silica Materials Synthesized via Sol-Gel Methods Modified with Ionic Liquid and Surfactant Molecules

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2008年第6期21卷 596-600页

作者： Cun-ying Xu ru-lan Tang yi-xin Hua Peng-xiang Zhang Kunming University of Science and Technology Kunming 650093 China

Mesoporous silica materials were synthesized via a sol-gel method employing a room temperature ionic liquid （1-butyl-3-methylimidazolium tetrafiuoroborate, [bmim][BF4]） as a new solvent medium and further modified with surfactant （hexadecyl-trimethyl-ammonium bromide, CTAB） as a pore templating material. The synthesized samples were characterized by the transmission electron microscopy, X-ray diffraction, and N2 adsorption-desorption techniques. The results indicated that the mesoporous silica synthesized by using [bmim][BF4] and CTAB as mixed templates showed better mesostructural order and smaller pore size, compared with mesoporous silica materials synthesized by using single [bmim][BF4] as template under the same conditions. This indicates that the presence of surfactant can affect the microstructures of silica prepared by＇the present synthesis method.

关键词： Mesoporous silica Ionic liquid Surfactant

Poly(β-cyclodextrin)-mediated Polylactide-cholesterol Stereocomplex Micelles for Controlled Drug Delivery

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 Journal of Polymer Science 2017年第6期35卷 693-693,694-699页

作者： Xiang-ru feng 丁建勋 ruxandra Gref Xue-si Chen Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied Chemistry Chinese Academy of Sciences Institute of Molecular Sciences CNRS Université Paris-Sud Université Paris Saclay

A series of host-guest interaction-adjusted polylactide stereocomplex micelles was prepared via the self-assembly of 4-armed poly（ethylene glycol）-block-poly（L-lactide/D-lactide）-cholesterol （4-armed PEG-b-PLLA/PDLA-CHOL） and poly（β-cyclodextrin）（PCD） with the molar ratios of CHOL/β-CD at 1：0.5, 1 ：l, and 1：2 in an aqueous environment. The hydrodynamic diameters of the micelles ranged from 84.1 nm to 107 nm depending on the molar ratio of CHOL/β-CD. It was shown that the micelle with the largest proportion of PCD possessed excellent abilities in drug release, cell internalization as well as proliferation inhibitory effect toward human A549 lung cancer cells. The results demonstrated that the stereocomplex and host-guest interactions-mediated PLA micelles exhibited great potential in sustained drug delivery.

关键词： Polylactide Stereocomplex micelle Poly(β-cyclodextrin) Host-guest interaction Controlled drug delivery

Effect of Increase in Price of Oil on Behavior of Private Car Owners in Beijing

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Population,Resources and Environment 2010年第1期8卷 55-61页

作者： yi ru Zhang Shiqiu College of Environmental Science and Engineering Peking University Beijing 100871 China

In order to understand the short-term response of private car owners to changes in the price of oil,a survey was conducted in Beijing after the gasoline price in China rose in June *** showed that private car drivers in Beijing reduced their trips in the one month period following the price *** trip characteristics and drivers' demographics significantly influenced price elasticity in the short term,including the purpose of the trip,the distance covered and the income of the car driver.

关键词： price elasticity private car travel behavior

Influence of die geometry on self-piercing riveting of aluminum alloy AA6061-T6 to mild steel SPFC340 sheets

在线全文

学校读者我要写书评

暂无评论

Advances in Manufacturing 2019年第2期7卷 209-220页

作者： Jiang-Hua Deng feng Lyu ru-Ming Chen Zhi-Song Fan School of Mechanical Engineering and Automation Fuzhou University Fuzhou 350116 People's Republic of China

The self-piercing riveting (SPR) process was used to join 2.0-mm-thick aluminum alloy 6061-T6 and 1.2-mm-thick mild steel SPFC340 sheets. SPR joints produced with a conventional flat-bottom die and conicalsection dies were investigated both experimentally and numerically. Lap shear tests were conducted under quasistatic conditions to evaluate the load-carrying capability of these SPR joints. The effect of variation in die geometry (such as variation in the die groove shape, cone height, and die radius) on the main mechanical response of the joints, namely the peak load and energy absorption, was discussed. The results showed that SPR joints produced with the conical-section dies exhibited a failure mode similar to those produced with a conventional die. All the joints failed by tearing of the top steel sheet. Cracks that occurred in the bottom aluminum alloy 6061-T6 sheet around the rivet leg were a result of tangential tensile stress. The cone height of a conical-section die is the most important parameter affecting the surface quality of Al/steel SPR joints. Conical-section dies with a moderate convex can ensure a good surface quality during the SPR process. In addition, SPR joints with single conical-section die allow higher tensile strength and energy absorption compared to those with double conical-section die.

关键词： Self-piercing riveting (SPR) Aluminum/steel dissimilar sheet Conical-section die Lap shear test

Effect of electrode change on solidification of slag and metal pool profile in electroslag remelting process

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 2021年第12期28卷 1582-1590页

作者： yi-ru Duan Bao-kuan Li Xue-chi Huang Zhong-qiu Liu School of Metallurgy Northeastern UniversityShenyang110819LiaoningChina

A two-dimensional axisymmetric model is established to study the effect of electrode change on the solidification of slag and metal pool profile during electroslag remelting *** basic considerations of flow and heat transfer are included in the model,and the growth of ingot is described by the dynamic mesh *** electrode melting rate is predicted based on the transient thermal conductivity model between slag and *** results indicate that in the electrode change stage,the slag temperature drops from 1847 to 1763 K gradually and the“hot heart”phenomenon is *** the metal pool profile is slightly changed with a depth decrease from 0.3984 to 0.3688 *** the heating and melting stage of new electrode,the maximum slag temperature firstly increases from 1763 to 1892 K,then decreases to 1845 K,and finally at 3558 s,the maximum slag temperature is stable at 1884 *** slag shell with a maximum volume of 7.31×10^(-3) m^(3) is formed at the electrode tip,and then,the solidified slag melts *** depth of metal pool firstly rises to 0.3700 m and then drops to 0.3565 *** the preheating temperature of the new electrode increases from 473 to 973 K,the maximum volume of solidified slag decreases from 0.00748 to 0.00592 m^(3),and the time from heating to melting of the new electrode decreases from 996 to 887 s.

关键词： Electroslag remelting Electrode change Metal pool profile Solidified slag Numerical simulation

Comparison Study on the Semiconductive and Dissolution Behaviour of 316L and Alloy 625 in Hydrochloric Acid Solution

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2020年第3期33卷 403-414页

作者： Zhu Wang Zi-ru Zhang Lei Zhang Zhe feng Min-Xu Lu Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China

The corrosion behaviour of 316L and Alloy 625 was investigated using cyclic polarization,electrochemical impedance spectroscopy,X-ray photoelectron spectroscopy,Auger electron spectroscopy and induced coupled plasma-optical emis sion *** results indicated that Alloy 625 showed better corrosion resistance than 316L and the prolonging immersion time could enhance corrosion resistance of the two *** passive film formed on the surface of 316L exhibited an electronic structure of p-p heterojunction,with Fe3O4 and Cr2O3 enriched in the outer and inner layers,***,Alloy 625 presented the electronic structure of n-p heterojunction dominated by the outer Fe2O3/NiFe2O4 and inner *** resulted in the opposite semiconductive properties of the passive films formed on the two *** the acid solutions,Fe and Mo suffered from selective dissolution while Cr and Ni were relatively *** corrosion rates were mainly dominated by the dissolution of *** 625 presented better corrosion resistance than 316L due to the obviously lower content of Fe and the higher content of Cr and Ni in the passive *** continuously selective dissolution of iron resulted in the increase in Cr/Fe ratio in the passive film,which was responsible for the enhancement in corrosion resistance.

关键词： Stainless steel Induced coupled plasma(ICP) Polarization X-ray photoelectron spectroscopy(XPS) Passive films

Robust microwave absorption in silver-cobalt hollow microspheres with heterointerfaces and electric-magnetic synergism:Towards achieving lightweight and absorption-type microwave shielding composites

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第7期138卷 245-255页

作者： Dian Yang Jun-ru Tao yi Yang Qian-Ming He Ming Wang Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function Manufacturing School of Chemistry and Chemical EngineeringSouthwest UniversityChongqing 400715China

Lightweight and high-efficiency microwave shielding materials based on high absorption loss are the hotspot of current ***,the silver-cobalt bimetallic hollow microspheres(Ag-Co-HM)with low reflection loss and broadband absorption efficiency were fabricated and then used to construct bimetallic hollow structures in polydimethylsiloxane/carbon nanotube composites(PDMS/CNT)to obtain the lightweight and absorption-type microwave shielding *** microwave absorption of Ag-Co-HM and the microwave shielding effectiveness(SE T)of the PDMS/CNT/Ag-Co-HM composites was evaluated and *** Ag-Co-HM with a molar ratio(Co/Ag)of 2.07 exhibited a low reflection loss as-46.6 dB at a thickness of 2.6 mm,and an effective absorption bandwidth of 8.40 *** SE T of the PDMS/CNT composites was greatly enhanced by the incorporation of the ***,the absorption coefficient(A)was also improved by adding the Ag-Co-HM and was much higher than the reflection *** composites exhibited absorption-type microwave shielding *** example,the average microwave SE T of 59.4 dB and A value of 0.78 are achieved in the PDMS/CNT/Ag-Co-HM composites containing 5 wt%CNTs and 10 wt%Ag-Co-HMs,which are much higher than the cor-responding values of 33.7 dB and 0.63 in the PDMS/CNT composites with only 5 wt%*** addition,the hollow structure of Ag-Co-HM endows the PDMS/CNT/Ag-Co-HM composites to have a low density.

关键词： Microwave shielding Absorption loss Lightweight Polydimethylsiloxane Carbon nanotube