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Impact of Improving Design Factor over 0.72 on the Safety and Reliability of Gas Pipelines and Feasibility Justification

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Chinese Journal of Mechanical Engineering 2012年第1期25卷 166-172页

作者： ZHAO Xinwei zhang Guangli luo Jinheng zhang hua Tubular Goods Research Institute of China National Petroleum Corporation Xi’an 710065China Petroleumtubular engineering Key Laboratory of China National Petroleum Corporation Xi’an 710065China

Many years experience of the operation of high stress (>72% specified minimum yield strength, SMYS) gas pipelines and statistical analysis results of pipeline incidents showed that the operating pipelines at stress levels over 72% SMYS have not presented problems in USA and Canada, and design factor does not control incidents or the safety of pipelines. Enhancing pipeline safety management level is most important for decreasing incident rate. The application history of higher design factors in the U.S and Canada was reviewed. And the effect of higher factors to the critical flaw size, puncture resistance, change of reliability with time, risk level and the arrest toughness requirements of pipeline were analyzed here. The comparison of pipeline failure rates and risk levels between two design factors (0.72 and 0.8) has shown that a change in design factor from 0.72 to 0.8 would bring little effect on failure rates and risk levels. On the basis of the analysis result, the application feasibility of design factor of 0.8 in China was discussed and the related suggestions were proposed. When an operator wishes to apply design factor 0.8 to gas pipeline, the following process is recommended: stress level of line pipe hydro test should be up to 100% SMYS, reliability and risk assessment at the design feasibility or conceptual stage should be conducted, Charpy impact energy should meet the need of pipeline crack arrest; and establish and execute risk based integrity management plan. The technology of pipeline steel metallurgy, line pipe fabrication and pipeline construction, and line pipe quality control level in China achieved tremendous progresses, and line pipe product standards and property indexes have come up to international advanced level. Furthermore, pipeline safety management has improved greatly in China. Consequently, the research for the feasibility of application of design factor of 0.8 in China has fundamental basis.

关键词： gas pipeline higher design factor safety and reliability risk integrity management

Grasping Force Planning and Control for Tendon-driven Anthropomorphic Prosthetic Hands

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Journal of Bionic Engineering 2018年第5期15卷 795-804页

作者： hua Deng huanxin luo Rong Wang Yi zhang State Key Laboratory of High-Performance Complex Manufacturing Central South University Changsha 410083 China School of Mechanical and Electrical Engineering Central South University Changsha 410083 China College of Mechanical & Electrical Engineering Changsha University Changsha 410022 China

A force planning and control method is proposed for a tendon-driven anthropomorphic prosthetic hand. It is necessary to consider grasping stability for the anthropomorphic prosthetic hand with multi degrees of freedom which aims to mimic human hands with dexterity and stability. The excellent grasping performance of the anthropomorphic prosthetic hand mainly depends on the accurate computation of the space position of finger tips and an appropriate grasping force planning strategy. After the dynamics model of the tendon-driven anthropomorphic prosthetic hand is built, the space positions of the finger tips are calculated in real time by solving the dynamic equations based on the Newton iteration algorithm with sufficient accuracy. Then, the balance of internal grasping force on the thumb is adopted instead of force closure of the grasped objects to plan the grasping forces of other fingers based on the method of the linear constraint gradient flow in real time. Finally, a fuzzy logic controller is used to control the grasping force of the prosthetic hand. The proposed force planning and control method is implemented on the tendon-driven anthropomorphic prosthetic hand and the experimental results dem- onstrate the feasibility and effectiveness of the proposed method.

关键词： prosthetic hands tendon-driven grasping force planning grasping force control

A Model of Vertical Isolation System with Gravitational Positive Feedback

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Chinese Physics Letters 1996年第8期13卷 568-571页

作者： HAO Peng-fei luo Jun zhang Ping-hua Department of Physics Huazhong University of science and TechnologyWuhan 430074 Institute of High Energy Physics Chinese Academy of SciencesBeijing 100080

An ideal model of vertical isolation system with gravitational positive feedback is proposed and some properties are *** theoretical analysis shows that the resonant frequency of the system could be reduced much effic... 详细信息

关键词： coefficient spring avi

Carbon Capture from Flue Gas Based on the Combination of Non-Contact Hydrophobic Porous Ceramic Membrane and Bubbling Absorption

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Journal of Renewable Materials 2023年第7期11卷 3143-3153页

作者： Yongde luo Jiang Jin hua zhang College of Materials Science and Engineering Nanjing Tech UniversityNanjing211816China

A hybrid system combined with a non-contact membrane and bubbling absorption is proposed to capture CO_(2) from flue *** non-contact way of membrane and liquid absorbent effectively avoids the reduction of gas diffusion flux through the ***-porosity ceramic membranes in hybrid systems are used for gas-solid separation in fuel gas *** to the high content of H_(2)O and cement dust in the flue gas of the cement plant,the membrane is hydrophobically modified by polytetrafluoroethylene(PTFE)to improve its anti-water,anti-fouling,and self-cleaning *** results show that the diffusion flux of CO_(2) through the membrane is still higher than 7.0×10^(−3) mol/m^(2)s(20%CO_(2) concentration)even under the influence of water and cement *** addition,slaked lime selected as the absorbent is cheap and the product after bubbling absorption is nano-scale light calcium *** sum up,the hybrid system combining non-contact membrane and bubbling absorption is expected to be used to capture carbon dioxide from the flue gas of the cement plant.

关键词： Porous ceramic membrane PTFE hydrophobic modification carbon capture nanoscale light calcium carbonate

High genetic diversity in the endangered and narrowly distributed amphibian species Leptobrachium leishanense

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Integrative Zoology 2015年第5期10卷 465-481页

作者： Wei zhang Zhenhua luo Mian ZHAO hua WU Institute of Evolution and Ecology International Research Centre of Ecology and EnvironmentSchool of Life SciencesCentral China Normal UniversityWuhanChina

Threatened species typically have a small or declining population size,which make them highly susceptible to loss of genetic diversity through genetic drift and *** diversity determines the evolutionary potential of a species;therefore,maintaining the genetic diversity of threatened species is essential for their *** this study,we assessed the genetic diversity of the adaptive major histocompatibility complex(MHC)genes in an endangered and narrowly distributed amphibian species,Leptobrachium leishanense in Southwest *** compared the genetic variation of MHC class I genes with that observed in neutral markers(5 microsatellite loci and cytochrome b gene)to elucidate the relative roles of genetic drift and natural selection in shaping the current MHC polymorphism in this *** found a high level of genetic diversity in this population at both MHC and neutral markers compared with other threatened amphibian *** positive selection was evident in the MHC class I *** higher allelic richness in MHC markers compared with that of microsatellite loci suggests that selection rather than genetic drift plays a prominent role in shaping the MHC variation pattern,as drift can affect all the genome in a similar way but selection directly targets MHC *** demographic analysis revealed no recent bottleneck events in ***,additional population decline will accelerate the dangerous status for this *** suggest that the conservation management of *** should concentrate on maximizing the retention of genetic diversity through preventing their continuous population *** their living habitats and forbidding illegal hunting are the most important measures for conservation of ***.

关键词： demography process genetic diversity major histocompatibility complex natural selection Leptobrachium leishanense

Yeast-Derived β-1,3-Glucan Substrate Significantly Increased the Diversity of Methanogens During In vitro Fermentation of Porcine Colonic Digesta

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Journal of Integrative Agriculture 2013年第12期12卷 2229-2234页

作者： luo Yu-heng LI hua luo Jun-qiu zhang Ke-ying Key Laboratory for Animal Disease-Resistance Nutrition of Sichuan Province and China Ministry of Education/Institute of Animal Nutrition Sichuan Agricultural University

The β-1,3-glucan from yeast has been extensively examined for its immuno-enhancing effects in ***,investigation on the relationship among β-glucan,gut microbiota and immune-modulating effects remains limited particularly in *** the critical roles of gut methanogens in the microbial fermentation,energy metabolism and disease resistance,we investigated the phylogenetic diversity of methanogens from fermented cultures of porcine colonic digesta with（G） or without（N） yeast β-glucan based on sequences of the archaeal 16S rRNA gene.A total of 145 sequences in the G library were assigned into 8 operational taxonomic units（OTUs） with the majority of sequences（114/145） related to strains Methanobrevibacter millerae or Methanobrevibacter gottschalkii with high identities ranging from 97.9 to 98.6%,followed by 23 sequences to Methanobrevibacter ruminantium,2 sequences to Methanobrevibacter smithii and one sequence to Methanobrevibacter *** 142 sequences in the N library were assigned to 2 OTUs with most sequences（127/142） related to strains *** or *** with sequence identities ranging from 97.9 to 98.5%,and 15 sequences related to *** with 97.9% *** diversity index showed that the G library exhibited significantly higher archaeal diversity（P0.05） and Libshuff analysis indicated the differences in the community structure between the two libraries were significant（P0.0001）.In conclusion,the current study provides evidence that addition of yeast β-glucan significantly increased the diversity of methanogens in in vitro fermented porcine colonic digesta.

关键词： β-glucan methanogen diversity pig colonic digesta in vitro

Foam/Film Alternating Multilayer Structure with High Toughness and Low Thermal Conductivity Prepared via Microlayer Coextrusion

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Chinese Journal of Polymer Science 2021年第5期39卷 566-572,I0006页

作者： Qi luo Hong-Ting PU Zhi-hua zhang Xiong zhang Cheng-Long Yu Department of Polymeric Materials School of Materials Science&EngineeringTongji UniversityShanghai 201804China Key Laboratory of Advanced Civil Engineering Materials(Ministry of Education) Tongji UniversityShanghai 201804China School of Physics Science and Engineering&Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology Tongji UniversityShanghai 200092China

Multilayer membranes prepared via microlayer coextrusion have attracted wide attention due to their unique properties and broad *** present study,the foam/film alternating multilayer sheets based on ethylene-vinyl acetate copolymer(EVA)and high-density polyethylene are successfully prepared via microlayer *** cells in the sheets are single-cell-array along the foamed EVA layers with uniform cell *** addition,the effects of layer number and foam relative thickness on morphology,mechanical properties,damping and heat insulation properties are *** cell size decreases significantly with increasing layer number due to the enhanced confine *** tensile strength,elongation at break,and heat insulation also increase ***,the mechanical damping properties change little in the observed ***,with higher relative thickness of EVA foam,the sheets have lower tensile strength and lower thermal conductivity,while the damping properties are enhanced in a specific frequency *** elongation at break of the optimized sample comes to 800%and the thermal conductivity decreases to 61 mW·m^(-1)·K^(-1),which shows high toughness and low thermal conductivity,indicating a possible method for preparing materials with high toughness and heat-insulating properties.

关键词： Multilayer Foam Coextrusion Toughness Thermal conductivity

Pyrochlore-based high-entropy ceramics for capacitive energy storage

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Journal of Advanced Ceramics 2022年第7期11卷 1179-1185页

作者： Yiying CHEN Junlei QI Minhao zhang Zixi luo Yuan-hua LIN State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

High-performance dielectrics are widely used in high-power systems,electric vehicles,and aerospace,as key materials for capacitor *** application scenarios under these extreme conditions require ultra-high stability and reliability of the ***,a novel pyrochlore component with high-entropy design of Bi1.5Zn_(0.75)Mg_(0.25)Nb_(0.75)Ta_(0.75)O_(7)(BZMNT)bulk endows an excellent energy storage performance of Wrec≈2.72 J/cm3 together with an ultra-high energy efficiency of 91%at a significant enhanced electric field Eb of 650 kV/***,the temperature coefficient(TCC)of BZMNT(~−220 ppm/℃)is also found to be greatly improved compared with that of the pure Bi1.5ZnNb1.5O7(BZN)(~−300 ppm/℃),demonstrating its potential application in temperature-reliable *** high-entropy design results in lattice distortion that contributes to the polarization,while the retardation effect results in a reduction of grain size to submicron scale which enhances the *** high-entropy design provides a new strategy for improving the high energy storage performance of ceramic materials.

关键词： high entropy bismuth-based pyrochlore high-temperature stability energy storage

Feasibility analysis for attitude estimation based on pulsar polarization measurement

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Journal of Zhejiang University-Science C(Computers and Electronics) 2013年第6期14卷 425-432页

作者： Nan luo Lu-ping XU hua zhang Qiang XIE School of Electronic Engineering Xidian University

One of the important characteristics of pulsar radiation is *** is considered not only as a probe for recognizing the structure of a magnetic field,but also as a lighthouse for estimating spacecraft attitude via orientation information between the pulsar and the *** polarization of a pulsar has been studied for decades,until recently applications to determination of spacecraft attitude have been seldom *** paper deals with analysis of the feasibility of applying polarization information to attitude *** stability factor(SFR) and observation fluctuation factor(OFR) are introduced to analyze the stability of a pulsar's polarized position *** on European Pulsar Network(EPN) data,several simulated instances are used to demonstrate that the accuracy requirement of attitude determination can be met via polarization *** SFR of a pulsar is evaluated using simulated polarization data,and the OFR is used to analyze the relationship between fluctuation extent and observation *** results show that the polarized measurement of candidate pulsars PSR B0470-28 and PSR B2319+60 reaches the specification for attitude determination.

关键词： Pulsar Polarization Attitude determination Stable factor