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Influence of bedding structure on stress-induced elastic wave anisotropy in tight sandstones

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第1期13卷 98-113页

作者： xiaying li Xinglin Lei Qi li Dianguo Chen State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China National Institute of Advanced Industrial Science and Technology(AIST) Tsukuba305-8567Japan Chongqing Dizhiyuan Geology and Engineering Testing Co. LtdChongqing401329China

To understand the evolution of stress-induced elastic wave anisotropy,three triaxial experiments were performed on sandstone specimens with bedding orientations parallel,perpendicular,and oblique to the maximum principal stress.P-wave velocities along 64 different directions on each specimen were monitored frequently to understand the anisotropy change at various stress levels by fitting Thomsen’s anisotropy *** results show that the elastic wave anisotropy is very sensitive to mechanical *** hydrostatic loading,the magnitude of anisotropy is reduced in all three ***,under deviatoric stress loading,the evolution of anisotropic characteristics(magnitude and orientation of the symmetry axis)is bedding orientation *** reversal occurs in specimens with bedding normal/oblique to the maximum principal stress.P-wave anisotropyε0 is linearly related to volumetric strain Sv and dilatancy,indicating that stress-induced redistribution of microcracks has a significant effect on P-wave velocity *** closure of initial cracks and pores aligned in the bedding direction contributes to the decrease of the ***,opening of new cracks,aligned in the maximum principal direction,accounts for the increase of the *** experimental results provide some insights into the microstructural behavior under loading and provide an experimental basis for seismic data interpretation and parameter selection in engineering applications.

关键词： Elastic wave anisotropy Stress-induced anisotropy Anisotropy reversal Bedding orientation Microstructure Tight sandstone

Hydromechanical behaviors of andesite under different stress states during fluid injection

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第4期13卷 727-744页

作者： Miao He Qi li xiaying li liang Xu Michael Kühn State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China Fluid Systems Modelling Section GFZ German Research Centre for GeosciencesPotsdamGermany Institute of Earth and Environmental Science University of PotsdamPotsdamGermany

Water reinjection into the formation is an indispensable operation in many energy engineering *** operation involves a complex hydromechanical(HM)coupling process and sometimes even causes unpredictable disasters,such as induced *** is acknowledged that the relative magnitude and direction of the principal stresses significantly influence the HM behaviors of rocks during ***,due to the limitations of current testing techniques,it is still difficult to comprehensively conduct laboratory injection tests under various stress conditions,such as in triaxial extension stress *** this end,a numerical study of HM changes in rocks during injection under different stress states is *** this model,the saturated rock is first loaded to the target stress state under drainage conditions,and then the stress state is maintained and water is injected from the top to simulate the formation injection *** attention is given to the difference in HM changes under triaxial compression and extension *** includes the differences in the pore pressure propagation,mean effective stress,volumetric strain,and stress-induced *** numerical results demonstrate that the differential stress will significantly affect the HM behaviors of rocks,but the degree of influence is different under the two triaxial stress *** HM changes caused by the triaxial compression stress states are generally greater than those of extension,but the differences decrease with increasing differential stress,indicating that the increase in the differential stress will weaken the impact of the stress state on the HM *** addition,the shear failure potential of fracture planes with various inclination angles is analyzed and summarized under different stress *** is recommended that engineers could design suitable injection schemes according to different tectonic stress fields versus fault occurrence to reduce the risk of

关键词： Water reinjection Stress state Hydromechanical(HM)coupling Injection-induced seismicity Numerical modeling

An effective method for laboratory acoustic emission detection and location using template matching

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第5期14卷 1642-1651页

作者： Xinglin Lei Tomohiro Ohuchi Manami Kitamura xiaying li Qi li National Institute of Advanced Industrial Science and Technology(AIST) Tsukuba305-8567Japan Geodynamics Research Center Ehime UniversityMatsuyama790-8577Japan State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China

In this paper, a template matching and location method, which has been rapidly adopted in microseismic research in recent years, is applied to laboratory acoustic emission(AE) monitoring. First, we used traditional methods to detect P-wave first motions and locate AE hypocenters in three dimensions. In addition, we selected events located with sufficient accuracy(normally corresponding AE events of relatively larger energy, showing clear P-wave first motion and a higher signal-to-noise ratio in most channels) as template events. Then, the template events were used to scan and match other poorly located events in triggered event records or weak events in continuous records. Through crosscorrelation of the multi-channel waveforms between the template and the event to be detected, the weak signal was detected and located using a grid-searching algorithm(with the grid centered at the template hypocenter). In order to examine the performance of the approach, we calibrated the proposed method using experimental data of different rocks and different types of experiments. The results show that the proposed method can significantly improve the detection capability and location accuracy, and can be applied to various laboratory and in situ experiments, which use multi-channel AE monitoring with waveforms recorded in either triggering or continuous mode.

关键词： Acoustic emission Template matching and location Waveform cross-correlation Grid search

Comparison of Five Endogenous Reference Genes for Specific PCR Detection and Quantification of Rice

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Rice science 2019年第4期26卷 248-256,I0006,I0007页

作者： ZHANG Xiujie JIN Wujun XU Wentao li xiaying SHANG Ying li Sha OUYANG Hongsheng College of Animal Sciences Jilin University Changchun 130062 China Development Center of Science and Technology Ministry of Agriculture and Rural Affairs Beijing 100176 China Biotechnology Research Institute Chinese Academy of Agricultural Sciences Beijing 100081China College of Food Science and Nutritional Engineering China Agricultural University Beijing 100083China

Endogenous reference genes (ERGs) provide vital information regarding genetically modified organisms (GMOs). The successful detection of ERGs can identity GMOs and the source of genes, verify stability and reliability of the detection system, and calculate the level of genetically modified (GM) ingredients in mixtures. The reported ERGs in rice include sucrose-phosphate synthase (SPS), phospholipase D (PLD), RBE4 and rice root-specific GOS9 genes. Based on the characteristics of ERGs, a new ERG gene, phosphoenolpyruvate carboxylase (PEPC), was selected, and further compared with the four existing genes. A total of 18 rice varieties and 29 non-rice crops were used to verify the interspecies specificity, intraspecies consistency, sensitivity, stability and reliability of these five ERGs using qualitative and quantitative PCR. Qualitative detection indicated that SPS and PEPC displayed sufficient specificity, and the detection sensitivity was 0.05% and 0.005%, respectively. Although the specificity of both RBE4 and GOS9 were adequate, the amplicons were small and easily confused with primer dimers. Non-specific amplification of the PLD gene was present in maize and potato. Real-time quantitative PCR detection indicated that PLD, SPS and PEPC displayed good specificity, with R2 of the standard curve greater than 0.98, while the amplification efficiency ranged between 90% and 110%. Both the detection sensitivities of PLD and PEPC were five copies and that of SPS was ten copies. RBE4 showed typical amplification in maize, beet and Arabidopsis, while GOS9 was found in maize, tobacco and oats. PEPC exhibited excellent detection sensitivity and species specificity, which made it a potentially useful application in GM-rice supervision and administration. Additionally, SPS and PLD are also suitable for GM-rice detection. This study effectively established a foundation for GMO detection, which not only provides vital technical support for GMO identification, but also is of grea

关键词： endogenous reference gene rice genetically modified crop phosphoenolpyruvate carboxylase gene sucrose-phosphate synthase gene phospholipase D gene starch branching enzyme 4 gene rice root-specific GOS9 gene

Copy number and zygosity determination of transgenic rapeseed by droplet digital PCR

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Oil Crop Science 2017年第2期2卷 84-94页

作者： Yuhua Wu Jun li xiaying li Jingang liang Yunjing li Xinhua Zeng Gang Wu Key Laboratory of Biology and Genetic Improvement of Oil Crops Ministry of Agriculture Oil Crops Research InstituteChinese Academy of Agricultural Sciences Wuhan China Science and Technoloty Center of Ministry of Agriculture China

Establishing an accurate and rapid method for copy number and zygosity determination can accelerate genetic engineering research process. In this study, droplet digital PCR (ddPCR), an emerging DNA absolute quantification technology, was used to identify single-copy homozygous transgenic lines from a batch of T0 transgenic rapeseed harboring 11 exogenous elements. Copy number of exogenous gene was evaluated in T0 generation based on calculated ratio between transgene and reference CruA gene, single-copy transformants were selected for selfing followed by subsequent zygosity analysis. Single-copy homozygous transgenic plants were successfully screened out in T1 generation by *** analysis with T2 seedlings verified that identification results of ddPCR were accurate and reliable. This study provides a novel rapid and accurate method for copy number and zygosity determination in transgenic rapeseed which overcomes disadvantages of traditional Southern analysis and recently developed real-time quantitative method.

关键词： droplet digital PCR (ddPCR) copy number zygosity homozygotes transgenic rapeseed

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高校实验动物平台管理模式研究

实验技术与管理 2020年第12期37卷 270-272,276页

作者：李夏莹北京大学生命科学学院实验动物中心北京100871

实验动物是现代生命科学研究的重要组成部分,是生物医学科研的基础和重要支撑条件。实验动物平台是进行实验动物饲养、管理、实验研究的重要场所。该文从北京大学实验动物中心平台建设和管理的实际经验出发,对实验动物设施设计及要求、... 详细信息

实验动物是现代生命科学研究的重要组成部分,是生物医学科研的基础和重要支撑条件。实验动物平台是进行实验动物饲养、管理、实验研究的重要场所。该文从北京大学实验动物中心平台建设和管理的实际经验出发,对实验动物设施设计及要求、动物管理、从业人员的职业安全的要点进行了阐述。

关键词：实验动物平台设施设计动物管理人员安全

功能性近红外光谱在抑郁症诊断及治疗监测中的临床应用

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重庆医科大学学报 2024年第8期49卷 931-936页

作者：李夏颖洪素况利重庆医科大学附属第一医院精神科重庆400016

抑郁症发病率快速上升,具有高致残率、高死亡率及高漏诊率等特点,目前抑郁症的诊断主要依靠临床症状和各种评定量表,缺乏客观的生物学指标。功能性近红外光谱是一种新兴无创的脑功能成像技术,2009年作为辅助诊断的生物学指标获得批准用... 详细信息

抑郁症发病率快速上升,具有高致残率、高死亡率及高漏诊率等特点,目前抑郁症的诊断主要依靠临床症状和各种评定量表,缺乏客观的生物学指标。功能性近红外光谱是一种新兴无创的脑功能成像技术,2009年作为辅助诊断的生物学指标获得批准用于精神疾病的鉴别,尤其是在抑郁症中其临床应用和研究快速增加。本文将从功能性近红外光谱在诊断抑郁症、判断疾病程度、监测治疗反应及在青少年抑郁症中的应用方面进行全面的综述,为临床研究和运用提供指导。

关键词：功能性近红外光谱抑郁症诊断监测

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珊瑚礁灰岩物性特征及工程性质研究进展

科技导报 2020年第20期38卷 57-70页

作者：钟毓汪稔李琦魏厚振李霞颖广西大学土木建筑工程学院南宁530004 中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室武汉430071 中国科学院大学北京100049

礁灰岩是珊瑚礁岩体的基础和主体部分,其物理力学特征及工程性质的研究在海洋开发建设中具有重要的战略意义。国内外对不同地区礁灰岩的研究表明,礁灰岩具有高孔隙、低密度、低强度的物理性质,且由于成岩作用复杂,其岩石结构发育具有不... 详细信息

礁灰岩是珊瑚礁岩体的基础和主体部分,其物理力学特征及工程性质的研究在海洋开发建设中具有重要的战略意义。国内外对不同地区礁灰岩的研究表明,礁灰岩具有高孔隙、低密度、低强度的物理性质,且由于成岩作用复杂,其岩石结构发育具有不均匀性,不同胶结程度的礁灰岩具有不同的应力响应,这与其他常规软岩及脆性岩石性质相比明显不同。目前对礁灰岩的研究总体上仍处于初级阶段,尚不能很好地解决珊瑚礁工程建设中的诸多难题,需要系统地开展更加深入的研究。建议首先进行科学的结构分类,加强对不同结构类型礁灰岩的物理力学特征、工程性质、微观胶结机理以及海水侵蚀作用对其物性特征影响等方面的研究。

关键词：礁灰岩物性特征工程性质珊瑚礁海洋开发建设

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足月单胎顺产初产妇产后盆底康复治疗

中国当代医药 2013年第13期20卷 183-184页

作者：李夏影广东省中山市三乡医院妇产科广东中山528463

目的探讨生物反馈联合电刺激盆底康复治疗对120例足月单胎顺产初产妇的治疗效果。方法选择120例足月单胎顺产产妇,随机均分为两组,对照组60例接受一般产后康复教育,实验组60例除接受产后康复教育外再采用生物反馈联合电刺激治疗,观察子... 详细信息

目的探讨生物反馈联合电刺激盆底康复治疗对120例足月单胎顺产初产妇的治疗效果。方法选择120例足月单胎顺产产妇,随机均分为两组,对照组60例接受一般产后康复教育,实验组60例除接受产后康复教育外再采用生物反馈联合电刺激治疗,观察子宫脱垂、阴道壁膨出、痔疮、尿失禁、腰骶痛等的发生率,通过尿垫实验、性生活调查问卷等评价产妇盆底肌功能恢复效果。结果实验组发生尿失禁、子宫脱垂、阴道壁膨出、痔疮、腰骶痛等盆底功能障碍发生率为8.3%,对照组发生率为40.0%,两组比较,差异具有统计学意义(P均<0.05)。结论产后妇女盆底康复治疗能够提高产后妇女盆底肌力,预防和治疗其盆底功能疾病,效果明显,有助于产后妇女身体康复和生活质量的提高。

关键词：顺产盆底康复治疗初产妇效果观察