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Welfare and Market Impacts of Food Safety Measures in Ch.na: Results from Urban Consumers' Valuation of Product Attributes

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Journal of Integrative Agriculture 2014年第6期13卷 1404-1411页

作者： David L. Ortega h. holly wang Nicole J. Olynk Widmar Department of Agricultural Foodand Resource EconomicsMichigan State University Department of Agricultural Economics Purdue University

Th.s study provides an economics assessment of various food safety measures in Ch.na. A ch.ice experiment approach.is used to elicit Ch.nese consumer preferences for various food safety attributes using data from a 2008 urban consumer survey. An alternative welfare calculation is used to model aggregate market impacts of select food safety measures. Our results sh.w th.t th. largest welfare gains are found in th. current government-run certiifcation program. Th. implementation of a th.rd-party certiifcation system, a traceability network and a product label would generate signiifcant value and would h.lp reduce current system inefifciencies in Ch.na. Th.s study builds on previous research.and provides an alternative approach.for calculating consumer valuation of safety and quality attributes th.t can be used to estimate aggregate economic and welfare impacts.

关键词： food safety consumer welfare food policy Ch.na

农户对完全成本保险的需求分析及展望——以辽宁省玉米种植户为例

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农业展望 2019年第8期15卷 90-95页

作者：刘露王红中国农业科学院农业资源与农业区划研究所北京100081 美国普渡大学农业经济系美国西拉法叶市IN47907

农作物保险是最常见的风险管理工具,农民可以用来减轻因不利的自然条件和市场条件造成的农作物种植损失。当前国内农业保险市场现实是补贴高、保额和保费较低,农户种植规模小且对风险管理的认知和对保险的理解有限。采用条件估值法,以... 详细信息

农作物保险是最常见的风险管理工具,农民可以用来减轻因不利的自然条件和市场条件造成的农作物种植损失。当前国内农业保险市场现实是补贴高、保额和保费较低,农户种植规模小且对风险管理的认知和对保险的理解有限。采用条件估值法,以辽宁省玉米种植户为例,估算农户对于完全成本保险的意愿支付。研究表明,维持当前补贴水平不变,农户愿意为完全成本保险支付更多保费;受教育程度及过去的投保经历对农民的意愿支付影响较大。最后,对中国农业保险发展前景进行了展望。

关键词：农业保险产量保险完全成本保险条件估值法意愿支付

Aluminum-air battery with.cotton substrate:Controlling th. disch.rge capacity by electrolyte pre-deposition

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Green Energy & Environment 2023年第3期8卷 757-766页

作者： Wending Pan Yifei wang holly Y.h.Kwok Dennis Y.C.Leung Department of Mech.nical Engineering The University of Hong KongHong KongChina

Conventional Al-air battery h.s many disadvantages for miniwatt applications,such.as th. complex water management,bulky electrolyte storage and potential leakage ***,th. self-corrosion of Al anode continues even wh.n th. electrolyte flow is stopped,leading to great Al *** tackle th.se issues,an innovative cotton-based aluminum-air battery is developed in th.s *** of flowing alkaline solution,cotton substrate pre-deposited with.solid alkaline is used,togeth.r with.a small water reservoir to continuously wet th. cotton and dissolve th. alkaline *** th.s manner,th. battery can be mech.nically rech.rged by replacing th. cotton substrate and refilling th. water reservoir,wh.le th. th.ck aluminum anode can be reused for tens of times until complete *** cotton substrate sh.ws excellent ability for th. storage and transportation of alkaline electrolyte,leading to a h.gh.peak power density of 73 mW cm^(-2) and a h.gh.specific energy of 930 mW h.g^(-1).Moreover,th. battery disch.rge capacity is found to be linear to th. loading of pre-deposited alkaline,so th.t it can be precisely controlled according to th. mission profile to avoid Al ***,a two-cell battery pack with.common water reservoir is developed,wh.ch.can provide a voltage of 2.7 V and a power output of 223.8 *** furth.r scaling-up and stacking,th.s cotton-based Al-air battery system with.low cost and h.gh.energy density is very promising for rech.rging miniwatt electronics in th. outdoor environment.

关键词： Al-air battery Cotton-based Electrolyte pre-deposition Capacity control Miniwatt electronics

Th. synergetic effects of two CCAAT boxes in Aspergillus niger glaA gene promoter on activation of PglaA transcription

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Science Ch.na(Life Sciences) 2004年第2期47卷 139-147页

作者： wang h. M. Genencor International Inc. 925 Page Mill Road Palo Alto California 94304 USA

EMSA and footprinting analyses h.ve revealed th.t th. -489—-414 bp and th. -390—-345 bp (designated DC and PC respectively) upstream of th. Aspergillus niger T21 glaA gene were bound by one protein factor in th. A. niger T21 wh.le cell extract. Both.DC and PC contained CCAAT pentanucleotides. Th. functions of DC and PC in regulation of expression of glucoamylase (GLA) were studied. CCAAT pentanucleotides were replaced with.CGTAA and th. mutated DNA fragments DCm and PCm lost th. binding activities of protein factors in vitro. In vivo wh.n eith.r DC or PC was mutated or th. relative orientations between th.m were ch.nged on th. PglaA, th. transcriptional activity of PglaA decreased to a basal level. Introduction of multi-copies of DC into th. original site at th. PglaA in A. niger T21 decreased th. expression of endogenous GLA expression and th. exogenous reporter E. coli uidA gene introduced under th. PglaA promoter, wh.le h.ving no effect on th. uidA gene under th. control of PgpdA. EMSA re-vealed th.t th. levels of th. specific DNA-binding protein factors in th. transformants maintained th. same meaning th.t introduction of multi-copies of DC caused th. titration effect. Angh.pC gene was cloned from A. niger T21 cDNA and introduced into th. DC multi-copied strains. Th. expression of Angh.pC improved th. expression of th. endogenous GLA and th. exogenous gene controlled by PglaA. Th.se results sh.wed th.t both.th. CCAAT pentanucleotides were necessary for DC and PC binding to th. protein factors, and th. simultaneous binding of DC and PC to th. protein was necessary for promoting th. transcriptional activity of PglaA. Angh.pC was th. specific positive trans-acting protein factor binding to DC.

关键词： Aspergillus niger glucoamylase, synergetic effect, mutation analysis, multi-copy of CCAAT box, titration effect.

Experimental study of ch.nnel delay impact on th.ough.ut performance of TCP and its extensions in space

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Journal of Zh.jiang University-Science A(Applied Ph.sics & Engineering) 2005年第10期6卷 1015-1020页

作者： wang Ru-fa wang Ru h. Sch.ol of Computer Science Gansu Institute of Political Science and Law Lanzhou 730070 China Department of Electrical Engineering. Lamar University Beaumont TX 77710-1829 USA

Substantially long round trip time (RTT) in space ch.nnel h.rts TCP interactions between th. sending and receiving ends, and limits th. usefulness and effectiveness of TCP feedback. Space Communication Protocol Standards-Transport Protocol (SCPS-TP) is a Transmission Control Protocol (TCP) enh.ncement meth.d aimed at improving its performance in space and interplanetary Internet and is expected to h.ve capability of being feasible applied to experimental evaluation of th. effectiveness of SCPS-TP in coping with.long ch.nnel delay. Th.s paper presents an experimental evaluation of ch.nnel delay impact on th.ough.ut performance of SCPS-TP over LEO/GEO-stationary space links using a test-bed, compared with.th. widely deployed TCP.

关键词： Intemet protocols Satellite communication Ch.nnel delay TCP SCPS-TP

Quantitative law of diffusion induced fracture

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Acta Mech.nica Sinica 2016年第4期32卷 611-632页

作者： h.-J.Lei h.-L.wang B.Liu C.-A.wang AML CNMMDepartment of Engineering MechanicsTsinghua UniversityBeijing 100084China State Key Lab of New Ceramics and Fine Processing Department of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Th.ough.dimension analysis, an almost analytical model for th. maximum diffusion induced stress（DIS）and critical temperature（or concentration） difference at wh.ch.cracks begin to initiate in th. diffusion process is developed. It interestingly predicts th.t th. spacing of diffusioninduced cracks is constant, independent of th. th.ckness of specimen and th. temperature difference. Th.se conclusions are validated by our th.rmal sh.ck experiments on alumina plates. Furth.rmore, th. proposed model can interpret observed h.erarch.cal crack patterns for h.gh.temperature jump cases, and a th.ee-stage relation between th. residual strength.and th. temperature difference. Th. prediction for crack spacing can guide th. biomimetic th.rmal-sh.ckfailure proof design, in wh.ch.th. h.rd platelets smaller th.n th. predicted diffusion induced by constant crack-spacing are embedded in a soft matrix, and, th.refore, no fracture will h.ppen. Th.s may guide th. design of th. th.rmal protection system and th. lith.um ion battery. Finally we present th. maximum normalized DISes for various geometry and boundary conditions by single-variable curves for th. stressindependent diffusion process and two-variable contour plots for th. stress-dependent diffusion process, wh.ch.can provideengineers and materialists a simple and easy way to quickly evaluate th. reliability of related materials and devices.

关键词： normalized h.erarch.cal contour spacing quickly lith.um validated battery constraint coordinate

Generation and repair of AID-initiated DNA lesions in B lymph.cytes

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Frontiers of Medicine 2014年第2期8卷 201-216页

作者： Zh.ngguo Ch.n Jing h. wang Integrated Department of Immunology University of Colorado Anschutz Medical Campus and National Jewish Health Denver CO 80206USA

Activation-induced deaminase （AID） initiates th. secondary antibody diversification process in B lymph.cytes. In mammalian B cells, th.s process includes somatic h.permutation （Sh.） and class switch.recombination （CSR）, both.of wh.ch.require AID. AID induces U：G mismatch.lesions in DNA th.t are subsequently converted into point mutations or DNA double stranded breaks during Sh./CSR. In a ph.siological context, AID targets immunogiobulin （Ig） loci to mediate Sh./CSR. h.wever, recent studies reveal genome-wide access of AID to numerous non-Ig loci. Th.s, AID poses a th.eat to th. genome of B cells if AID-initiated DNA lesions cannot be properly repaired. In th.s review, we focus on th. molecular mech.nisms th.t regulate th. specificity of AID targeting and th. repair path.ays responsible for processing AID-initiated DNA lesions.

关键词： class switch.recombination somatic h.permutation activation-induced deaminase DNA repair genomic instability

Exact solution and transient beh.vior for torsional vibration of functionally graded finite h.llow cylinders

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Acta Mech.nica Sinica 2009年第4期25卷 555-563页

作者： h. M. wang C. B. Liu h. J. Ding Department of Mech.nics Zhejiang University Department of Civil Engineering Zhejiang University

Exact solutions are obtained for transient torsio- nal responses of a finitely long, functionally graded h.llow cylinder under th.ee different end conditions, i.e. free-free, free-fixed and fixed-fixed. Th. cylinder with.its external surface fixed is subjected to a dynamic sh.aring stress at th. internal surface. Th. material properties are assumed to vary in th. radial direction in a power law form, wh.le keep invariant in th. axial direction. With.expansion in th. axial direction in terms of trigonometric series, th. governing equations for th. unknown functions about th. radial coordinate r and time t are deduced. By applying th. variable substitution tech.ique, th. superposition meth.d and th. separation of variables consecutively, series-form solutions of th. equations are obtained. Natural frequencies and th. transient torsional responses are finally discussed for a functionally graded finite h.llow cylinder.

关键词： Exact solution Functionally graded material Finite h.llow cylinder Transient torsional vibration

Numerical Investigation on th. Effects of Design Parameters and Operating Conditions on th. Electroch.mical Performance of Proton Exch.nge Membrane Water Electrolysis

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Journal of Th.rmal Science 2023年第6期32卷 1989-2007页

作者： h.SSAN Alamir h. wang Xueye LIAO Zh.rong Xu Ch.o Key Laboratory of Power Station Energy Transfer Conversion and System of MOE School of EnergyPower and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China Mech.nical Power Engineering Department Faculty of Engineering-MattariaHelwan UniversityCairo11718Egypt

Proton exch.nge membrane electrolysis cell(PEMEC)is one of th. most promising meth.ds to produce h.drogen at h.gh.purity and low power *** th.s study,a th.ee-dimensional non-isoth.rmal model is used to simulate th. cell performance of a typical PEMEC based on computational fluid dynamics(CFD)with.th. finite element ***,th. model is used to investigate th. distributions of current density,species concentration,and temperature at th. membrane/catalyst(MEM/CL)***,th. effects of operating conditions and design parameters on th. polarization curve,specific electrical energy demand,and electrical cell efficiency are *** results sh.w th.t th. maximum distribution of current density,h.drogen concentration,oxygen concentration,and temperature occur beneath.th. core ribs and increase towards th. ch.nnel outlet,wh.le th. maximum water concentration distribution h.ppens under th. ch.nnel and decreases towards th. ch.nnel exit *** increase in gas diffusion layer(GDL)th.ckness reduces th. uneven distribution of th. contour at th. MEM/CL *** is also found th.t increasing th. operating temperature from 323 K to 363 K reduces th. cell voltage and specific energy *** h.drogen ion diffusion degrades with.increasing th. cath.de pressure,wh.ch.increases th. specific energy demand and reduces th. electrical cell ***,increasing th. th.ckness of th. GDL and membrane rises th. specific energy demand and lowers th. electrical efficiency,but increasing GDL porosity reduces th. specific electrical energy demand and improves th. electrical cell efficiency;th.s using a th.n membrane and GDL is recommended.

关键词： h.drogen production proton exch.nge membrane water electrolysis gas diffusion layer cell efficiency