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Experimental study on failure characteristics of single-sided unloading rock under different intermediate principal stress conditions

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International Journal of Mining Science and Technology 2023年第3期33卷 275-287页

作者： Chongyan liu Guangming Zhao Wensong Xu Xiangrui Meng zhixi liu Xiang Cheng Gang Lin State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and TechnologyHuainan 232001China Key Laboratory of Safe and Effective Coal Mining Ministry of EducationAnhui University of Science and TechnologyHuainan 232001China Post-Doctoral Research Station Huaibei Mining Corporation LimitedHuaibei 235006China Laboratoire de Géologie Ecole Normale SupérieureParis 75005France

Investigation of unloading rock failure under differentσ_(2)facilitates the control mechanism of excavation surrounding *** study focused on single-sided unloading tests of granite specimens under true triaxial *** strength and failure characteristics were studied with micro-camera and acoustic emission(AE)***,the choice of test path and the effect ofσ_(2)on fracture of unloading rock were *** show that the increasedσ_(2)can strengthen the stability of single-sided unloading *** unloading,the rock’s free surface underwent five phases,namely,inoculation,particle ejection,buckling rupture,stable failure,and unstable rockburst ***,atσ_(2)≤30 MPa,the b value shows the following variation tendency:rising,dropping,significant fluctuation,and dropping,with dispersed damages ***σ_(2)≥40 MPa,the tendency shows:a rise,a decrease,a slight fluctuation,and final drop,with concentrated damages *** unloading,AE energy is mainly concentrated in the micro-energy *** the increasedσ_(2),the micro-energy ratio *** contrast,low,medium and large energy ratios drop *** increased tensile fractures and decreased shear fractures indicate that the failure mode of the unloading rock gradually changes from tensile-shear mode to tensile-split *** fractional dimension of the rock fragments first increases and then decreases with an inflection point at 20 *** distribution of SIF on the planes changes asσ_(2)increases,resulting in strengthening and then weakening of the rock bearing capacity.

关键词： Single-sided unloading Acoustic emission True triaxial Intermediate principal stress Stress intensity factor

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高围压下砂岩循环加-卸载损伤本构及损伤阈值

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高压物理学报 2020年第4期34卷 106-114页

作者：刘之喜安徽理工大学土木建筑学院安徽淮南232001

在深部巷道掘进过程中,岩体受周期荷载和高地应力共同作用,一般的强度准则无法对岩石的应力-应变曲线进行描述和表征,而高地应力下岩石的循环加-卸载本构是预测深部巷道在周期荷载作用下长期稳定性的关键,因此关于高围压下岩石的本构研... 详细信息

在深部巷道掘进过程中,岩体受周期荷载和高地应力共同作用,一般的强度准则无法对岩石的应力-应变曲线进行描述和表征,而高地应力下岩石的循环加-卸载本构是预测深部巷道在周期荷载作用下长期稳定性的关键,因此关于高围压下岩石的本构研究具有一定的工程意义。岩石受外部荷载直至破坏的过程是旧裂纹扩展和新裂纹增长、扩展的过程,已有的研究表明,单位体积岩石裂纹数服从Weibull分布,Griffith准则认为岩石的破坏是由岩石的裂纹扩展所导致的,为此通过对Weibull建立的统计损伤本构扩展,基于裂纹数服从Weibull分布以及裂纹扩展服从Griffith准则,建立了高围压下岩石循环加-卸载统计损伤本构。通过本构的等式变换,对本构损伤阈值进行了研究,并进一步以砂岩的偶数次循环加-卸载试验数据对本构参数进行拟合,得到参数的演化规律,将本构理论值与砂岩奇数次循环加-卸载试验数据对比,验证了本构模型的正确性,为高围压下岩石的循环加-卸载本构研究提供了新的思路。

关键词：高围压循环加-卸载本构模型损伤阈值

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Molecular Basis for Sesterterpene Diversity Produced by Plant Terpene Synthases

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Plant Communications 2020年第5期1卷 41-52页

作者： Qingwen Chen Jianxu Li zhixi liu Takaaki Mitsuhashi Yuting Zhang Haili liu Yihua Ma Juan He Tetsuro Shinada Tsutomu Sato Yong Wang Hongwei liu Ikuro Abe Peng Zhang Guodong Wang State Key Laboratory of Plant Genomics and National Center for Plant Gene Research Institute of Genetics and Developmental BiologyThe Innovative Academy of Seed DesignChinese Academy of SciencesBeijing 100101China National Key Laboratory of Plant Molecular Genetics Center for Excellence in Molecular Plant SciencesShanghai Institute of Plant Physiology and EcologyChinese Academy of SciencesShanghai 200032China Graduate School of Pharmaceutical Sciences University of Tokyo7-3-1 HongoBunkyo-kuTokyo 113-0033Japan State Key Laboratory of Mycology Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China Key Laboratory of Synthetic Biology Institute of Plant Physiology and EcologyShanghai Institutes for Biological SciencesChinese Academy of SciencesShanghai 200032China University of Chinese Academy of Sciences Beijing 100039China Graduate School of Science Osaka City University3-3-138 SugimotoSumiyoshiOsaka 558-8585Japan Department of Applied Biological Chemistry Faculty of AgricultureGraduate School of Science and TechnologyNiigata University8050 Ikarashi-2Niigata 950-2181Japan

Class I terpene synthase(TPS)generates bioactive terpenoids with diverse *** synthase(sester-TPS,C25),a branch of class I TPSs,was recently identified in ***,the catalytic mechanisms of sester-TPSs are not fully ***,we first identified three nonclustered functional sester-TPSs(AtTPS06,AtTPS22,and AtTPS29)in Arabidopsis ***06 utilizes a type-B cyclization mechanism,whereas most other sester-TPSs produce various sesterterpene backbones via a type-A cyclization *** then determined the crystal structure of the AtTPS18–FSPP complex to explore the cyclization mechanism of plant *** used structural comparisons and site-directed mutagenesis to further elucidate the mechanism:(1)mainly due to the outward shift of helix G,plant sester-TPSs have a larger catalytic pocket than do mono-,sesqui-,and di-TPSs to accommodate GFPP;(2)type-A sester-TPSs have more aromatic residues(five or six)in their catalytic pocket than classic TPSs(two or three),which also determines whether the type-A or type-B cyclization mechanism is active;and(3)the other residues responsible for product fidelity are determined by interconversion of AtTPS18 and its close ***,this study improves our understanding of the catalytic mechanism of plant sester-TPS,which ultimately enables the rational engineering of sesterterpenoids for future applications.

关键词： terpenoid terpene synthase sesterterpene cyclization mechanism crystal structure

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Recently duplicated sesterterpene(C25) gene clusters in Arabidopsis thaliana modulate root microbiota

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Science China(Life Sciences) 2019年第7期62卷 947-958页

作者： Qingwen Chen Ting Jiang Yong-Xin liu Haili liu Tao Zhao zhixi liu Xiangchao Gan Asis Hallab Xuemei Wang Juan He Yihua Ma Fengxia Zhang Tao Jin M. Eric Schranz Yong Wang Yang Bai Guodong Wang State Key Laboratory of Plant Genomics and National Center for Plant Gene Research Institute of Genetics and Developmental BiologyThe Innovative Academy of Seed DesignChinese Academy of SciencesBeijing 100101China Key Laboratory of Synthetic Biology Institute of Plant Physiology and EcologyShanghai Institutes far Biological SciencesChinese Academy of SciencesShanghai 200032China Biosystematics Group Wageningen University6708 PB WageningenThe Netherlands CAS-JIC Centre of Excellence for Plant and Microbial Sciences (CEPAMS) Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing 100101China Max Planck Institute for Plant Breeding Research Carl-von-Linne-Weg 1050829 KolnGermany Forschungszentrum Jiilich Plant Sciences (IBG-2) Wilhelm-Johnen-Straβe52428 JillichGermany China National Genebank-Shenzhen the Beijing Genomics Institute (BGI-Shenzhen)Shenzhen 518083China College of Advanced Agricultural Sciences University of Chinese Academy of SciencesBeijing 100039China

Land plants co-speciate with a diversity of continually expanding plant specialized metabolites(PSMs) and root microbial communities(microbiota).Homeostatic interactions between plants and root microbiota are essential for plant survival in natural environments.A growing appreciation of microbiota for plant health is fuelling rapid advances in genetic mechanisms of controlling microbiota by host *** have long been proposed to mediate plant and single microbe ***,the effects of PSMs,especially those evolutionarily new PSMs,on root microbiota at community level remain to be ***,we discovered sesterterpenes in Arabidopsis thaliana,produced by recently duplicated prenyltransferase-terpene synthase(PT-TPS) gene clusters,with neo-functionalization.A single-residue substitution played a critical role in the acquisition of sesterterpene synthase(sesterTPS) activity in Brassicaceae ***,we found that the absence of two root-specific sesterterpenoids,with similar chemical structure,significantly affected root microbiota assembly in similar *** results not only demonstrate the sensitivity of plant microbiota to PSMs but also establish a complete framework of host plants to control root microbiota composition through evolutionarily dynamic PSMs.

关键词： plant specialized metabolites microbiota sesterterpene terpene synthase

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Impact of immunization programs on 11 childhood vaccine-preventable diseases in China: 1950–2018

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The Innovation 2021年第2期2卷 109-116页

作者： Jinhua Pan Yesheng Wang Lingsheng Cao Ying Wang Qi Zhao Shenglan Tang Wenfeng Gong Lei Guo zhixi liu Zexuan Wen Bo Zheng Weibing Wang Department of Epidemiology School of Public HealthFudan UniversityShanghai 200032China School of Public Health Key Laboratory of Public Health Safety of Ministry of EducationFudan UniversityShanghai 200032China National Immunization Program Chinese Center for Disease Control and PreventionBeijing 102206China Department of Social Medicine School of Public HealthFudan UniversityShanghai 200032China Duke Global Health Institute Duke UniversityDurhamNC 27708USA Bill and Melinda Gates Foundation SeattleWA 98109USA These authors contributed equally

To evaluate the achievements of China’s immunization program between 1950 and 2018,we chose 11 vaccine-preventable diseases(VPDs)as representative notifiable diseases and used annual surveillance data obtained between 1950 and 2018 to derive disease incidence and mortality ***-Poisson and polynomial regression models were used to estimate the impacts of specific vaccine programs,and life-table methods were used to calculate the loss of life expectancy,years of life lost,and loss of working *** total notification number for the 11 VPDs was 211,866,000 from 1950 to *** greatest number occurred in 1959,with a total incidence of 1,723 per million *** 1978 to 2018,a substantial decline was observed in the incidence of major infectious *** incidence of pertussis fell 98%from 126.35 to 1.58 per million,and the incidences of measles,meningococcal meningitis,and Japanese encephalitis fell 99%,99%,and 98%,*** regression models showed that most of the 11 diseases exhibited dramatic declines in morbidity after their integration into the Expanded Program on Immunization(EPI),while varicella and paratyphoid fever,which were not integrated into the EPI,showed increased *** 1978 to 2018,the total life expectancy for the 11 VPDs increased by 0.79 years,and similar results were obtained for different age *** has had great success in controlling VPDs in recent decades,and improving vaccination coverage is a key aspect of controlling VPDs in China.

关键词： China vaccine-preventable diseases morbidity mortality immunization

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Modeling and Control Strategy Research on Diesel Engine High-Pressure Common Rail System

Modeling and Control Strategy Research on Diesel Engine High...

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第43届中国控制会议

作者： zhixi liu Tao Chen Peng Zhou Daxin Chen Shuang Wang Chaoyang Sun State Key Laboratory of Engines Tianjin University FAW Jiefang Automotive Co. Ltd

To achieve precise control of rail pressure and enhance the performance of a diesel engine,a feedforward + sliding mode active disturbance rejection control(F-SMADRC) algorithm is proposed. Focusing on a six-cylinder high-pressure common rail diesel engine,the mathematical models of its fuel metering unit,high-pressure fuel pump,common rail pipe,and fuel injector are derived. An experimental design is implemented to identify the parameters and validate the accuracy of the controlled object model. Finally,the proposed control algorithm is validated on the Simulink simulation platform,including testing its control effectiveness under both steady-state and transient conditions. A comparative evaluation is conducted against traditional PID and ADRC algorithms,considering performance metrics such as overshoot,response time,and absolute ***,the adaptive and anti-interference capabilities of the algorithm are explored under conditions of injector nozzle blockage,sudden changes in engine speed and fuel injection pulse width. Simulation results demonstrate that the proposed control algorithm exhibits minimal fluctuations in steady-state conditions,low overshoot and fast response time in transient conditions,effectively regulating rail pressure,and possessing robustness and adaptive capabilities.

关键词： rail pressure control F-SMADRC algorithm six-cylinder high-pressure common rail diesel engine object model

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Construction of DNA Fingerprint Using SSR Marker for Hybrid Rice Cultivars Approved by Hunan Province

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Agricultural Biotechnology 2012年第4期1卷 7-10,14页

作者： Qingcai ZHAN Zifa XIAO Keyong ZHU zhixi liu Zhaohua LI Shuzhen ZENG Laboratory of Biotechnology Hunan Rice Research Institute Graduate School of Central South University Longping Branch

[Objective] This study aimed to construct DNA fingerprint for hybrid rice cultivars those have been approved by Hunan Province. [Method] The primers which produced polymorphic and bright DNA bands were selected to construct the DNA molecular fingerprint map for 77 major hybrid rice cultivars approved by Hunan Province. [ Result] A total of 48 SSR primers were selected. Every cultivar had its unique fingerprint map so that the obtained data could identify differ- ent hybrid rice cultivars. [ Conclusion] This study made great contributions to the perfection of hybrid rice germplasm identification.

关键词： Hybrid rice SSR marker Fingerprint map Germplasm identification

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Impact of the national hepatitis B immunization program in China:a modeling study

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Infectious Diseases of Poverty 2022年第5期11卷 99-100页

作者： zhixi liu Mengying Li David W.Hutton Abram L.Wagner Ye Yao Wenlong Zhu Lingsheng Cao Shenglan Tang Jinhua Pan Yesheng Wang Qi Zhao Hong Ren Ying Wang Weibing Wang School of Public Health Shanghai Institute of Infectious Disease and BiosecurityFudan UniversityShanghaiChina Department of Social Medicine School of Public HealthFudan UniversityShanghaiChina 不详

Background:Elimination of hepatitis B virus(HBV)is a striking challenge for countries with high or moderate disease ***,using China as a practical case to share experiences for similar countries may accelerate the achievement of the WHO 2030 target of 90%reduction in HBV-related *** aim to evaluate the impact of national HBV immunization strategies in China;and the feasibility to achieve WHO 2030 targets under diferent ***:We constructed an expanded Susceptible-Exposed-Infectious-Recovered(SEIR)model and decision treeMarkov model to estimate the epidemic of HBV in China,assess the feasibility of 2030 Elimination Goals through the projections and conduct the economic *** square method was used to calibrate the expanded SEIR model by yearly data of laboratory-confrmed HBV cases from 1990 to *** models were separately used to evaluate the impact and cost-efectiveness of HBV vaccine by comparing prevalence of chronic HBV infections,qualityadjusted life-years(QALYs),incremental cost efectiveness ratio and beneft–cost ratio(BCR)under various intervention options,providing a basis for exploring new containment ***:Between 1990 and 2020,the number of chronic HBV infections decreased by 33.9%.The current status quo would lead to 55.73 million infections(3.95%prevalence)in 2030,compared to 90.63 million(6.42%prevalence)of the“Without the NIP”scenario(NIP:National Immunization Program),114.78 million(8.13%prevalence)without any *** prevention of mother to child transmission(PMTCT)strategy showed a net beneft as 12,283.50 dollars per person,with BCR as 12.66,which is higher than that of universal vaccination at *** with no screening and no vaccination,the PMTCT strategy could save 7726.03 dollars for each QALY ***:Our fndings proved the HBV vaccination has demonstrated a substantial positive impact on controlling the epidemic of HBV in terms of efectiveness and economy af

关键词： Hepatitis B National immunization program Prevalence Economic analysis Susceptible-ExposedInfectious-Recovered modeling

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Vaccination as an alternative to non-drug interventions to prevent local resurgence of COVID-19

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Infectious Diseases of Poverty 2022年第2期11卷 101-101页

作者： Jinhua Pan Wenlong Zhu Jie Tian zhixi liu Ao Xu Ye Yao Weibing Wang School of Public Health Key Lab of Public Health Safety of the Ministry of EducationFudan UniversityShanghai 200032China 不详 Department of Biostatics School of Public HealthFudan UniversityShanghai 200032China

Background:While a COVID-19 vaccine protects people from serious illness and death,it remains a concern when and how to lift the high-cost and strict non-pharmaceutical interventions(NPIs).This study examined the joint efect of vaccine coverage and NPIs on the control of local and sporadic resurgence of COVID-19 ***:Between July 2021 and January 2022,we collected the large-scale testing information and case number of imported COVID-19 patients from the website of the National Health Commission of China.A compartment model was developed to identify the level of vaccine coverage that would allow safe relaxation of NPIs,and vaccination strategies that can best achieve this level of *** applied Monte Carlo simulation 50000 times to remove random fuctuation efects and obtain ftted/predicted epidemic curve based on various parameters with 95% confdence interval at each time ***:We found that a vaccination coverage of 50.4% was needed for the safe relaxation of NPIs,if the vaccine efectiveness was 79.3%.The total number of incidence cases under the key groups frstly strategy was 10^(3) times higher than that of accelerated vaccination *** needed 35 months to fully relax NPIs if the key groups frstly strategy was implemented,and 27 months were needed with the accelerated vaccination *** combined the two strategies,only 8 months are needed to achieve the vaccine coverage threshold for the fully relaxation of *** analyses results shown that the higher the transmission rate of the virus and the lower annual vaccine supply,the more difcult the epidemic could be under *** the transmission rate increased 25% or the vaccination efectiveness rate decreased 20%,33 months were needed to reduce the number of total incidence cases below ***:As vaccine coverage improves,the NPIs can be gradually *** that threshold is reached,however,strict NPIs are still needed to control the *** more trans

关键词： COVID-19 Vaccine Non-pharmaceutical interventions Compartment model Monte Carlo simulation

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岩石单轴压缩试验中能量演化分析方法

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煤炭学报 2020年第9期45卷 3131-3139页

作者：刘之喜王伟罗吉安缪广红安徽理工大学深部煤矿采动响应与灾害防控国家重点实验室安徽淮南232001 安徽理工大学煤矿安全高效开采省部共建教育部重点实验室安徽淮南232001 河海大学岩土所江苏南京210098 安徽理工大学力学与光电物理学院安徽淮南232001

为了探究岩石单轴压缩试验过程中的能量演化规律,利用RMT-150b岩石力学测试系统采用相同的加载速率对白砂岩分别进行了单轴压缩试验、单轴分级加卸载试验。基于裂纹产生及扩展模型研究,假设疲劳损伤和裂纹间的界面摩擦对弹性能无影响,... 详细信息

为了探究岩石单轴压缩试验过程中的能量演化规律,利用RMT-150b岩石力学测试系统采用相同的加载速率对白砂岩分别进行了单轴压缩试验、单轴分级加卸载试验。基于裂纹产生及扩展模型研究,假设疲劳损伤和裂纹间的界面摩擦对弹性能无影响,则可以认为单轴压缩中与单轴分级加卸载各卸载点荷载相等处,弹性能均相等。基于上述假设对单轴压缩过程中弹性能、耗散能、弹性能占总能量比例、耗散能占总能量比例、弹性能与耗散能比值等进行分析。通过利用红砂岩单轴循环加卸载中弹性能的演化规律验证了这一假设的正确性。研究结果表明:①通过对单轴压缩试验过程中能量演化规律分析发现塑性耗散能、弹性能、滞回效应耗散能存在于岩石单轴压缩的各个阶段。②部分滞回效应能可以储存在岩石内部并且随着荷载增大呈线性增长。③弹性能与塑性能的增长速率都随着荷载增大而增大,通过对弹性能与耗散能比值分析,得出了不同荷载范围内岩石的弹性能与耗散能增长速率的比较,并且在岩石强度的80%左右处弹性能与耗散能比值达到最大,与弹性能量指数相等,说明该分析方法对岩石能量演化趋势的分析具有一定的合理性。④通过红砂岩单轴循环加卸载试验分析发现,疲劳损伤和裂纹间的界面摩擦会产生塑性变形导致岩石加卸载曲线逐渐右移,且对弹性能无影响。⑤根据单轴分级加卸载各卸载点弹性能分析单轴压缩试验过程中能量演化规律,并使用单轴循环加卸载试验的弹性能演化规律进行验证,说明了分析方法的正确性。

关键词：能量演化单轴压缩试验单轴分级加卸载单轴循环加卸载弹性能量指数

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