检索结果-南通市图书馆

The Coagulation Process of Nascent Fibers in PAN Wet-spinning

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology(materials science) 2010年第2期25卷 200-205页

作者：陈娟葛曷一 school of material science and engineering University of Jinan

The evolvement of microstructure and properties of nascent fibers during coagulation process in the polyacrylonitrile （PAN） wet-spinning and the effect of coagulation bath conditions on the structure and properties of the nascent fibers were investigated by the means of X-ray diffraction （XRD）, scanning electron microscope （SEM）, fiber fineness machine, fiber tensile strength machine, etc. The experimental results indicate that the nascent fibers become denser and have fewer inner defects, the diameter of nascent fibers shrink and the crystallization degree of nascent fibers gradually increases with the increasing of coagulation time. Too large spinning tension leads to grooves occurring on surface of fibers. To obtain circular cross-section of nascent fibers the optimal coagulation conditions are 50 ℃, 65% （concentration） and 0.9 （draw ratio）.

关键词： PAN wet-spinning coagulation nascent fibers

Characterization of tensile fracture in heavily alloyed Al-Si piston alloy

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5期21卷 380-385页

作者： Guo-hua ZHANG~(1,2),Jian-xin ZHANG~3,Bing-chao li~3,Wei CAI~1 1.school of materials science and engineering,Harbin Institute of technology,Harbin 150001,china 2.shandong Binzhou Bohai Piston Co.,Ltd,Binzhou 256602,china 3.school of materials science and engineering,shandong university,Ji'nan 250061,china [a] school of materials science and engineering Harbin Institute of Technology Harbin 150001 China [b] shandong Binzhou Bohai Piston Co. Ltd Binzhou 256602 China [c] school of materials science and engineering Shandong University Ji'nan 250061 China

This paper focuses on a typical automotive piston material to characterize its fractographic appearance after tensile rupture. The fracture of this heavily alloyed Al—Si alloy takes place in a brittle *** consecutive eutectic zone is found to break by debonding of Si platelets from the Al matrix or by fracturing of Si *** various intermetallic particles break up complicatedly under the stress field of the propagating *** fracture tends to pass through or approach to the boundary between the eutectic Al matrix and Si platelets and there is a strong interaction between the propagating crack and the obstructing intermetallic compound.A tensile fracture mechanism in the heavily alloyed Al-Si alloy is elucidated.

关键词： tension test aluminum alloys facets fracture

Infrared Spectra of La_(0.65)Ba_xMnO_(3-δ) Oxides

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 2001年第4期20卷 255-258页

作者： Jifan Hu1, Hongwei Qjn 1), Yanming Hao2, Yangxian li2, Yizhong Wang3), Zhenxi Wan g3) 1) Department of Physics, shandong university, Jinan 250100, china 2) school of Electronic engineering and material science, Hehei university of technology. Tianjing 30 shandong Univ Dept Phys Jinan 250100 Peoples R China Hebei Univ Technol Sch Elect Engn & Mat Sci Tianjin 300130 Peoples R China Chinese Acad Sci Inst Phys Beijing 100080 Peoples R China

The infrared spectra of La_(0.65)Ba_xMnO_(3-|?￡(c) (x = 0.35, 0.33 and 0.30) were investigated experimentally. The result shows that the sample La_(0.65)Ba_xMnO_(3-|?￡(c) has the largest Curie temperature and the smallest resistivity and wave number of the stretching vibration mode of MnO_6 octaheUron at 300 K among the investigated samples. However, the absorption strength for the stretching vibration mode of Mn0_6 octahedron in La_(0.65)Ba_xMnO_(3-|?￡(c) is stronger for parainagnetic phase than that for ferromagnelic phase, which may be connected with the reducing of the dynamic in- coherent Jahn-Teller distortion below Curie temperature. In addition, the large shift of wave number for the stretching mode at the temperatures from 293 to 423 K has been observed in La_(0.65)Ba_xMnO_(3-|?￡(c), which may be due to the in- crease of the Mn-O bond length with temperature increasing.

关键词： infrared spectra colossal magnetoresistance effect perovskite manganite stretching vibration mode Jahn-Teller distortion

Preparation of microencapsulatedα-olefin drag reducing polymer used in oil pipeline transportation

在线全文

学校读者我要写书评

暂无评论

Petroleum science 2011年第1期8卷 99-107页

作者： li Bing Xing Wenguo Dong Guilin Chen Xiangjun Zhou Ningning Qin Zhanbo Zhang Changqiao school of Chemistry and Chemical engineering Shandong UniversityShandong 250061China linyi Institute of Product Quality Supervision and Inspection Shandong 276004China shandong Institute of Metrology Shandong 250014China shandong Quality Certification Centre Shandong 250014China

Microcapsules containing oil drag-reducing polymer particles were prepared by melting-scattering and condensing of polyethylene wax,in-situ polymerization of urea and formaldehyde,and interfacial polymerization of styrene *** related processes were studied by a molecular dynamics simulation method,and molecular design of microcapsule isolation agent was carried out on the basis of the *** technologies for preparing microencapsulated oil drag-reducing polymer particles were compared and the circulation drag reducing efficiency of the microencapsulated polymer particles was evaluated based on the characterization results and their dissolution *** design of a microcapsule isolation agent suggests that a-olefin polymer particles can be stably dispersed in water by using long-chain alkyl sodium salt surfactant which can prevent the agglomeration ofα-olefin polymer *** results of simulation of the adsorption process shows that the amount of alkyl sodium salt surfactant can directly affect the stability of microencapsulatedα-olefin polymer particles, and there must be a minimum critical amount of *** characterization of the morphology by Scanning Electron Microscopy（SEM） and comparison of the static pressure stability,especially the conditions of reaction and technological control of microcapsules with different shell materials,microencapsulation of a-olefin polymer particles with poly-（urea-formaldehyde） as shell material was selected as the optimum scheme,because it can react under mild conditions and its technological process can be controlled in a large *** relationship of drag reducing rate and dissolving time of microcapsules showed that the formation of microcapsules did not affect the maximum drag reducing rate,and the drag reducing rate of each sample can reach about 35%along with the dissolving time,*** did not affect the drag reducing property ofα-olefin polymer.

关键词： α-olefin polymer molecular design coating material microcapsule preparation stability and solubility drag reducing property

Fabrication and abrasive wear properties of metal matrix composites reinforced with three-dimensional network structure

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2006年第6期25卷 671-679页

作者： WANG Shouren GENG Haoran li Kunshan SONG Bo WANG Yingzi HUI linhai school of Mechanical engineering Jinan University Jinan 250022 China The Key Laboratory of liquid Structure and Heredity of materials Shandong University Jinan 250014 China school of materials science Jinan University Jinan 250022 China

Reticulated polyurethane was chosen as the preceramic material for preparing the porous preform using the replication process. The immersing and sintering processes were each performed twice for fabricating a high-porosity and super-strong skeleton. The aluminum magnesium matrix composites reinforced with three-dimensional network structure were prepared using the infiltration technique by pressure assisting and vacuum driving. light interfacial reactions have played a profitable role in most of the ceramic-metal systems. The metal matrix composites interpenetrated with the ceramic phase have a higher wear resistance than the metal matrix phase. The volume fraction of ceramic reinforcement has a significant effect on the abrasive wear, and the wear rate can be decreased with the increase of the volume fraction of reinforcement.

关键词： metal matrix composites infiltration fficdon and wear three dimensional network structure microstructure

A self-powered biosensor based on triboelectric nanogenerator for dual-specificity bacterial detection

在线全文

学校读者我要写书评

暂无评论

InfoMat 2024年第3期6卷 117-130页

作者： Wei lu Xiaoqiang Wang Congyu Wang Ke Gong Jiawei li Xue li Peng Wang State Key Laboratory of Heavy Oil Processing College of Chemistry and Chemical EngineeringChina University of Petroleum(East China)Qingdaothe People's Republic of China Institute of Oceanology Chinese Academy of SciencesQingdaothe People's Republic of China school of material science and engineering China University of Petroleum(East China)Qingdaothe People's Republic of China State Key Laboratory of Microbial technology Shandong UniversityQingdaothe People's Republic of China Guangxi Academy of sciences Nanningthe People's Republic of China

Pathogenic and corrosive bacteria pose a significant risk to human health or economic *** specific,sensitive,and on-site detection of these bacteria is thus of paramount significance but remains *** inspiration from immunoassays with primary and secondary antibodies,we describe here a rational design of microbial sensor(MS)under a dualspecificity recognition strategy using Pseudomonas aeruginosa(***)as the detection *** the MS,engineered aptamers are served as the primary recognition element,while polydopamine-N-acetyl-D-galactosamine(PDA-Gal NAc)nanoparticles are employed as the secondary recognition element,which will also generate and amplify changes in the output voltage sig*** achieve self-powering capability,the MS is constructed based on a triboelectric nanogenerator(TENG)with the specific aptamers immobilized on the TENG electrode *** as-prepared MS-TENG system exhibits good stability in output performance under external forces,and high specificity toward ***,with no cross-reactivity observed.A linear relationship(R^(2)=0.995)between the output voltage and *** concentration is established,with a limit of detection estimated at around 8.7×10^(3) CFU mL^(-1).The utilization of PDA-Gal NAc nanoparticles is found to play an important role in enhancing the specific and reliability of detection,and the underlying mechanisms are further clarified by computational *** addition,the MS-TENG integrates a wireless communication module,enabling real-time monitoring of bacterial concentration on mobile *** work introduces a pioneering approach to designing self-powered smart microbial sensors with high specificity,using a double recognition strategy applicable to various bacteria beyond ***.

关键词： bacterial detection high specificity microbial sensor triboelectric nanogenerator wireless transmission

Synthesis and characterization of amphiphilic centipede-like copolymer PS-PS-PMAA

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

science china Chemistry 2011年第10期54卷 1584-1589页

作者： li aixiang CHEN JiMing CUI YuShuang lu zaijun school of material science and engineering Shandong University of Technology Zibo 255049 China school of Chemistry and Chemical engineering Shandong University Jinan 250100 China

A well-defined amphiphilic centipede-like copolymer of styrene and methacrylic acid (PS-PS-PMAA) was synthesized by the combination of living anionic polymerization and atom transfer radical polymerization (ATRP). The synthetic approach involves the first coupling reaction of polystyrene (PS) backbone bearing 1,1-diphenylethene (DPE) pendant groups with living polystyryllithium (PSli), and sequential anionic polymerization of t-butyl methacrylate (tBMA) initiated by resulting 1,1-diphenylmethyl anion, and final hydrolysis of obtained PS-PS-PtBMA. The centipede-like copolymer PS-PS-PMAA was characterized by 1H NMR, IR, GPC, and SLS measurements. The critical micelle concentration (CMC) of PS-PS-PMAA in water was determined by fluorescence probe technique. The self-assembly behavior of PS-PS-PMAA in water-THF mixture was observed by TEM. The results showed that the micellar morphology can be varied, such as vesicle, sphere, and agglomerate, depending on the THF content. These phenomena are worthy of further research in polymer physics field.

关键词： atom transfer radical polymerization living anionic polymerization amphiphilc centipede-like copolymer self-assembly

Synthesis and characterization of well-defined comb-like branched polymers

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical science and engineering 2008年第4期2卷 407-411页

作者： aixiang li zaijun lu Zijian lu school of material science and engineering Shandong University of TechnologyZibo 255049China school of Chemistry and Chemical engineering Shandong UniversityJinan 250100China Teaching Affairs Department Shandong University of TechnologyZibo 255049China

Well-defined comb-like branched polymers having one branch in each repeating unit have been suc-cessfully synthesized by the coupling reaction of living polystyrene(PS)and polyisoprene(PI)anions with 1,1-diphenylethenyl(DPE)groups along PS backbone pre-pared via atom transfer radical polymerization(ATRP)of 4-vinylbenzyloxy benzophenone(Sc)followed by Wittig *** resulting comb-like branched poly-mers were characterized by IR,1H-NMR,gel permeation chromatography(GPC)and static light scattering(SLS)in *** effect of living chains and DPE group molar ratio on grafting efficiency was *** results show the coupling reaction of living chains and DPE groups was highly effective,and the coupling efficiency can be controlled via the feed molar ratios of living chains and DPE ***,the effect of molecular weights of backbone(PSe)and PSli or PIli on grafting efficiency was also *** results show that when excess living polymers were used,the almost quantitative grafting efficiency could be achieved.

关键词： atom transfer radical polymerization living anionic polymerization coupling reaction comb-like branched polymer

Role of bonding filling on HER/OER/ORR multifunctional catalytic activity in transition-metals-doped PdPX(X=S,Se,Te)

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

Rare Metals 2024年第10期43卷 5126-5140页

作者： Hai-Hua Huang Wei li Cheng-Chao Hu Xue-Qin Sun lin-Guo lu Xiao-Feng Fan school of materials science and engineering Laboratory of Sensitive Materials and DevicesShandong Department of EducationLiaocheng University school of Environmental and material engineering Yantai University Department of Physics University of Puerto Rico Key Laboratory of Automobile materials (Jilin university) Ministry of EducationCollege of Materials Science and EngineeringJilin University

The development of stable and highly efficien multifunctional electrocatalysts for the hydrogen evolution reaction （HER）,oxygen reduction reaction （ORR） and oxygen evolution reaction （OER） are essential for the efficient conversion and storage of renewable *** significant advantages of single-atom catalysts,such as strong metal slab interactions,unsaturated coordination and efficient atomic utilization,have opened new avenues for designing multifunctional ***,based on density functional theory,a single atom doped PdPX system was designed as a multifunctional electrocatalyst,which demonstrated the synergistic effect between defects and transition metal atoms and led to enhanced catalytic *** results showed that PdPS/PdPSe with P/X vacancy,PdPTe with P/Pd vacancy and Co/Rh/Ir@PdPX exhibited promising HER ***@PdPS（Se）,with an overpotential of 0.56（0.44） V,was predicted to be a promising OER ***,Rh（Ir）@PdPS（Se）catalysts exhibited efficient catalytic properties for ORR Besides,Co@PdPS（Se）,Rh（Ir）@PdPSV（S）,Co@PdP-SeV（Se）and Ir@PdPSV（S）-1exihibited multifunctional catalytic performance with moderate ***,the origin of catalytic activity was revealed by using the crystal orbital Hamilton populations *** a strong adsorption system,proper filling of the anti-bonding state can increase the energy of the system,weaken the adsorption strength,and facilitate the desorption of intermediates Conversely,augmenting bonding states can enhance its adsorption *** findings provide theoretica guidance for the design and fabrication of novel multifunctional electrocatalysts in terms of filling of bondingstate.

关键词： Density functional theory Electrocatalyst Two-dimensional PdPX Water splitting