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In vitro biocompatibility evaluation of silk-fibroin/ polyurethane membrane with cultivation of HUVECs

Frontiers of Materials Science 2014年第1期8卷 63-71页

作者： Mei ZHOU Wei-Ci wang yong-Gui LIAO Wen-Qi LIU Miao YU Chen-xi OUYANG Department of Vascular Surgery Union Hospital Tongji Medical College Huazhong University of Science and Technology Wuhan 430022 China

In order to investigate the in vitro biocompatibility of a novel polyurethane （PU） membrane modified by incorporation of superfine silk-fibroin powder （SFP）, which was prepared for small-diameter vascular grafts, with the cultivation of human umbilical vein endothelial cells （HUVECs）, PU and SFP were mixed with the ratios of 9：1, 7：3, 5：5, 3：7 （PU：SFP） to make four composite materials. Unmodified PU and polytetrafluoroethylene （PTFE） were added as control groups. CCK-8 assay was used to evaluate the cytotoxicity of these biomaterials. Data were processed using SPSS, and P〈 0.05 was considered to be statistically significant. Adherence and spreading of HUVECs on the surface of specimens was observed using direct contact cultivation. The toxicity ratings of the novel composites were grade 0-1, which is in the acceptable range. In all the experimental groups except control, SFP/PU with ratio of 1：9 had the least cytotoxicity property, and more content of SFP in the composite showed no improvement of the biocompatibility. HUVECs strongly attached to and grew on the surface of the biomaterials, and proliferated rapidly. The proliferation ability increased with increased proportion of SFP; however the cell quantity on the surface of the materials decreased when the proportion of SFP was equal to or larger than that of PU in the composite. It is concluded that this novel material has excellent cellular affinity with no cytotoxicity to HUVECs. Adding SFP gives PU better biocompatibility, while further research on optimum blend ratios is still needed.

关键词： polyurethane (PU) silk-fibroin (SF) small diameter vascular graft biocompatibility human umbilical vein endothelial cell (HUVEC)

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Detection performance and inversion processing of logging-while-drilling extra-deep azimuthal resistivity measurements

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Petroleum Science 2019年第5期16卷 1015-1027页

作者： Lei wang Shao-Gui Deng Pan Zhang Ying-Chang Cao Yi-Ren Fan xi-yong Yuan School of Geosciences China University of PetroleumQingdao 266580ShandongChina Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071ShandongChina CNPC Key Laboratory for Well Logging China University of PetroleumQingdao 266580ShandongChina

We present systematic investigations on the physics,detection performance and inversion of logging-while-drilling extradeep azimuthal resistivity measurements(EDARM).First,the definitions of EDRAM measurements are discussed,followed by the derivation of the attenuation and phase-shift geometrical factors to illustrate the relative contributions of formation units to the observed ***,a new definition of detection depth,which considers the uncertainty of inversion results caused by the data noise,is proposed to quantify the detection capability of ED ***,the B ayesian theory associated with Markov chain Monte Carlo sampling is introduced for fast processing of EDARM *** results show that ED ARM is capable of detecting the azimuth and distance of remote bed boundaries,and the detection capability increases with increasing spacing and resistivity *** EDARM tool can accommodate a large range of formation resistivity and is able to provide the resistivity anisotropy at arbitrary relative dipping *** addition,multiple bed boundaries and reservoir images near the borehole are readily obtained by using the Bayesian inversion.

关键词： Extra-deep azimuthal resistivity measurements(EDARM) Detection performance Inversion method Reservoir imaging Detection of multiple bed boundaries

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Enhanced power saving mechanism for supporting multicast services in 802.11 wireless LANs

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第6期10卷 828-833页

作者： yong HE Rui-xi YUAN xiao-jun MA Jun LI Center for Intelligent & Networked Systems Tsinghua University Beijing 100084 China Thomson Broadband R&D Co. Ltd Beijing 100085 China

Traditional 802.11 power saving mechanism (PSM) treats multicast and broadcast traffic equally, and suffers sig-nificant performance degradation with multicast background traffic. This paper proposes an enhanced PSM that effectively dif-ferentiates multicast streams. It re-arranges the virtual bitmap of the traffic indication map (TIM) to carry traffic status for mul-ticast groups and introduces a concept of sequential transmission of multi-addressed data to facilitate differentiation among mul-ticast groups. Our analysis shows that the enhanced PSM can effectively save power in mixed traffic environments.

关键词： 802.11 Wireless network Power saving Multicast services

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ETI： an efficient index for set similarity queries

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Frontiers of Computer Science 2012年第6期6卷 700-712页

作者： Lianyin JIA Jianqing xi Mengjuan LI yong LIU Decheng MIAO School of Computer Science&Engineering South China University of TechnologyGuangzhou 530641China Department of Computer Science Yunnan Agricultural UniversityKunming 650201China Library Yunnan Normal UniversityKunming 650092China

Set queries are an important topic and have attracted a lot of attention. Earlier research mainly concentrated on set containment queries. In this paper we focus on the T-Overlap query which is the foundation of the set similarity query. To address this issue, unlike traditional algorithms that are based on an inverted index, we design a new paradigm based on the prefix tree （trie） called the expanded trie index （ETI） which expands the trie node structure by adding some new properties. Based on ETI, we convert the T- Overlap problem to finding query nodes with specific query depth equaling to T and propose a new algorithm called T- Similarity to solve T-Overlap efficiently. Then we carry out a three-step framework to extend T-Overlap to other simi- larity predicates. Extensive experiments are carried out to compare T-Similarity with other inverted index based algorithms from cardinality of query, overlap threshold, dataset size, the number of distinct elements and so on. Results show that T-Similarity outperforms the state-of-the-art algorithms in many aspects.

关键词： expanded trie index (ETI) set similarity query T-Overlap T-Similarity algorithm T-SimilarityExact algorithm

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Sol-Gel Synthesis of Normal Spinel LiMn_2O_4 and Its Characteristics

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Journal of Wuhan University of Technology(Materials Science) 2002年第3期17卷 1-4页

作者： LEI Jia-heng SUN Yu-bin CHEN yong-xi wang Jin-rong XUE Li-hui Wuhan University of Technology

Normal spinel LiMn 2O 4 was synthesized by sol-gel method using lithium nitrate,manganese nitrate,citric acid and ethylene glycol as raw materials. LiMn 2O 4 was characterized by XRD,TG-DTA,IR,SEM and *** optimum conditions for the synthesis were *** acid and ethylene glycol were mixed with molar ratio of 0.25,and the mixture was esterified at 140℃ for 4 *** lithium nitrate and manganese nitrate were added with molar ratio of 0.6. In the system,the total molar of cations was equal to that of citric acid. At last, reflux the system at 105℃ for 2 hours. Dried gel was fired at 600℃ for 8 hours. Particle diameters of raw product were about 100 nm mainly. Further research shows that lithium ion of LiMn 2O 4 is easy to be extracted,and normal spinel λ-MnO 2 can be obtained after lithium ion extraction.

关键词： sol gel method synthesis of LiMn 2O 4 λ MnO 2

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Fluorescence Emission from Small Molecules Containing Amino Group

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Chinese Chemical Letters 2006年第4期17卷 502-504页

作者： Dong Jun wang Dan Dan JIA yong Guang ZHAO xi Hai SHEN Yue Dong YANG Hebei Normal University of Science and Technology Department of Chemistry Qinhuangdao 066600

After the treatment of oxygen gas, the small molecules containing amine group could emit fluorescence. Oxidation was believed to play an important role in the formation of fluorescence centers. Compared to previous re... 详细信息

关键词： Fluorescence amine oxidation oxygen.

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Numerical Study of Dam-Break Induced Tsunami-Like Bore with A Hump of Different Slopes

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China Ocean Engineering 2017年第6期31卷 683-692页

作者： CHENG Du ZHAO xi-zeng ZHANG Da-ke CHEN yong Ocean College Zhejiang University Zhoushan 316021 China

Numerical simulation of dam-break wave, as an imitation of tsunami hydraulic bore, with a hump of different slopes is performed in this paper using an in-house code, named a Constrained Interpolation Profile （CIP）-based model. The model is built on a Cartesian grid system with the Navier Stokes equations using a CIP method for the flow solver, and employs an immersed boundary method （IBM） for the treatment of solid body boundary. A more accurate interface capturing scheme, the Tangent of hyperbola for interface capturing/Slope weighting （THINC/SW） scheme, is adopted as the interface capturing method. Then, the CIP-based model is applied to simulate the dam break flow problem in a bumpy channel. Considerable attention is paid to the spilling type reflected bore, the following spilling type wave breaking, free surface profiles and water level variations over time. Computations are compared with available experimental data and other numerical results quantitatively and qualitatively. Further investigation is conducted to analyze the influence of variable slopes on the flow features of the tsunami-like bore.

关键词： dam break tsunami-like bore CIP method VOF method immersed boundary method

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Microstructure and deformation mechanism of dual-phase Al_(0.5)CoCrNiFe high-entropy alloy

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Rare Metals 2023年第6期42卷 2020-2027页

作者： yong-Gang Tong Nan Tian Hong-Feng Huang Zhi-Bin Zhang xiu-Bing Liang xi-xi Ji Jing-Zhong Fang yong-Le Hu College of Automotive and Mechanical Engineering Changsha University of Science and TechnologyChangsha410114China Key Laboratory of New Processing Technology for Nonferrous Metal and Materials Guilin University of TechnologyMinistry of EducationGuilin541004China National Institute of Defense Technology Innovation Academy of Military Sciences PLA ChinaBeijing100071China

Dual-phase high-entropy alloys containing facecentered cubic(fcc) and body-centered cubic(bcc) phases achieve a combination of high strength and high ductility,which attract extensive *** with singlephase high-entropy alloys,the dual-phase structure generates more complex deformation mechanisms such as structural transformation and interactions between grain boundaries and dislocations during *** order to understand the structural transformation of the dual-phase high-entropy alloy during deformation and its effect on mechanical properties,Al_(0.5)CoCrNiFe high-entropy alloy was prepared and its deformation mechanism was investigated by molecular dynamics simulations combined with *** results show that phase transformation occurred during deformation,and dislocation slip was the main deformation *** addition,there was significant dislocation pile-up at the interface between fcc and bcc phases after tensile *** and strain rates significantly affected the mechanical properties and deformation behavior of high-entropy *** low temperature and high strain rate,the dislocation density of the alloy increases after stretching,resulting in the enhancement of tensile strength.

关键词： Dual-phase high-entropy alloy(HEA) Microstructure Deformation behavior Dislocation

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Impact of hydraulic perforation on fracture initiation and propagation in shale rocks

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Science China(Technological Sciences) 2016年第5期59卷 756-762页

作者： ZHAO xi JU Yang YANG yong SU Sun GONG WenBo School of Mechanics & Civil Engineering China University of Mining & Technology Beijing 100083 China State Key Laboratory for Geo-mechanics & Deep Underground Engineering China University of Mining & Technology Xuzhou 221006 China State Key Laboratory of Coal Resources and Safe Mining China University of Mining & Technology Beijing 100083 China SINOPEC Shengli Oilfield Company Geological Scientific Research Institute Dongying 257015 China

To enhance the oil and gas recovery rate, hydraulic fracturing techniques have been widely adopted for stimulation of low-permeability reservoirs. Pioneering work indicates that hydraulic perforation and layout could significantly affect fracture initiation and propagation in low-permeability reservoir rocks subjected to complex in-situ stresses. This paper reports on a novel numerical method that incorporates fracture mechanics principles and the numerical tools FRANC3D and ANSYS to investigate the three-dimensional initiation and propagation behavior of hydro-fracturing cracks in shale rock. Considering the transverse isotropic property of shale rocks, the mechanical parameters of reservoir rocks attained from laboratory tests were adopted in the simulation. The influence of perforation layouts on the 3D initiation of hydro-fracturing fractures in reservoir rocks under geo-stresses was quantitatively illuminated. The propagation and growth of fractures in three dimensions in different perforating azimuth values were illustrated. The results indicate that： 1） the optimal perforation direction should be parallel to the maximum horizontal principal stress, 2） the crack plane gradually turns toward the direction of the maximum horizontal principal stress when they are not in parallel, 3） compared with the linear and symmetric pattern, the staggered perforation is the optimal one, 4） the proper perforation density is four to six holes per meter, 5） the optimal perforation diameter in this model is 30 ram, and 6） the influence of the perforation depth on the fracture initiation pressure is low.

关键词： hydraulic fracturing perforation shale rocks in-situ stresses numerical simulation fracture mechanics

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Experimental validation of sound quality simulation and optimization of a four-cylinder diesel engine

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第5期14卷 341-352页

作者： Jie MAO Zhi-yong HAO Kang ZHENG Guo-xi JING Department of Energy Engineering Zhejiang University

A novel sound quality simulation approach was proposed to optimize the acoustic performance of a four-cylinder diesel *** element analysis,single-input and multiple-output technology,flexible multi-body dynamics,and boundary element codes were used to acquire the hexahedron-element model,experimental modal frequencies,vibration velocities,and structurally radiated noise of the block,*** simulated modal frequencies and vibration velocities agreed well with the experimental data,which validated the finite-element *** acoustic response showed that considerable acoustic power levels existed in 1500-1900 Hz and 2300-2800 Hz as the main frequency ranges to optimize the block ***,the optimal block is determined in accordance with the novel approach,which reduces the overall value,high-frequency amplitudes,and peak values of acoustic power;thus,the loudness,sharpness,and roughness decline to make the sound quieter,lower-pitched,and smoother,***,the optimal block was cast and *** results reveal that the sound quality of the optimal-block engine is substantially improved as numerically expected,which verifies the effectiveness of the research approach.

关键词： Diesel engine Flexible multi-body dynamics Sound quality simulation Block optimization Sound quality improvement

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