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An analysis of the rate of isomerization in molecules with an asymmetric double well potential

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Chinese Journal of Chemistry 1993年第6期11卷 499-508页

作者： meishan Zhao Department of Chemistry and The James Franck Institute The University of ChicagoChicagoIllinois 60637U.S.A. Department of Physics and Chemistry Southeast UniversityNanjing.

The classical theory of the rate of unimolecular isomerization developed by Gray and Rice as extended by Zhao and Rice is applied to the calculation of the rate of isomerization in model systems which have linear asymmetric double well potentials. We are interested in this system for two reasons. First, we are interested in the detailed dynamical processes for the mentioned system because it is widely related to practical chemical reactions. Second, the present model system has an asymmetric double well potential, which provides a different test of the accuracy of the approximations used in the Gray-Zhao-Rice theory than posed by previous applications. We have calculated relaxation rates and relaxation times for the model systems on different time scales. We find that for the systems under studies the Gray-Zhao-Rice version of the classical theory of isomerization rate yields values in good agreement with those generated from trajectory calculations and from the Reactive Island theory of De Leon et al.

关键词： rate An analysis of the rate of isomerization in molecules with an asymmetric double well potential well

基于SBAS-InSAR技术和BP神经网络的高位远程滑坡危险性分析研究

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昆明理工大学学报（自然科学版） 2024年第3期49卷 65-74页

作者：喜文飞成鑫杨志全刘美杉郭峻杞昆明理工大学公共安全与应急管理学院云南昆明650093 云南师范大学地理学部云南昆明650500 昆明理工大学应急管理部地质灾害风险防控与应急减灾重点实验室云南昆明650093 云南省高校高烈度地震山区交通走廊工程地质病害早期快速判识与防控重点实验室云南昆明650093

高位远程滑坡具有突发性强、致灾范围广等特点,严重威胁人民生命和财产安全.针对滑坡危险性评价过程中评价单元划分缺乏对滑坡形状考虑的问题,利用SBAS-InSAR和BP神经网络模型对云南头寨滑坡进行危险性评价研究.首先,利用2018年4月—201... 详细信息

高位远程滑坡具有突发性强、致灾范围广等特点,严重威胁人民生命和财产安全.针对滑坡危险性评价过程中评价单元划分缺乏对滑坡形状考虑的问题,利用SBAS-InSAR和BP神经网络模型对云南头寨滑坡进行危险性评价研究.首先,利用2018年4月—2019年4月的299幅Sentinel-1A升降轨影像获取研究区时间序列地表形变信息,然后,分别利用斜坡单元和网格单元为评价单元进行对比分析,对初步提取的坡度、坡向、高程等8个评价因子进行皮尔逊相关性分析和多重共线性分析,完善评价因子体系.最后,利用BP神经网络模型对滑坡危险性等级划分.结果显示,考虑滑坡形状的斜坡单元评价效果优于网格单元评价结果,斜坡单元更能反映单体滑坡危险区域的空间分布,且模型AUC值为0.724,表明该模型可适用于单体滑坡.其中极高危险区和高危险区主要分布在滑坡后壁和滑坡侧壁部分区域,极低风险区和低风险区基本处于滑坡面和坡脚区域.本研究结果可为单体高位远程滑坡灾害前期预警和防灾减灾工作提供技术支撑.

关键词：高位远程滑坡 SBAS-InSAR技术 BP神经网络评价单元划分滑坡危险性评价

结构方程模型在中西医结合防治心血管疾病领域的应用探索

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中华中医药学刊 2024年第6期42卷 34-40页

作者：高雪菲王子涵陆美杉黄力李琳北京中医药大学北京100029 中日友好医院中西医结合心内科北京100029

心血管病发生率正逐年攀升,病死率占比颇高,已成为威胁人类健康的首要疾病。中西医结合治疗是中国医学特色疗法和优势手段之一,在心血管疾病领域应用广泛,但在目前研究中,由于中医理论的复杂性和传统统计方法的局限性,针对疾病中医病机... 详细信息

心血管病发生率正逐年攀升,病死率占比颇高,已成为威胁人类健康的首要疾病。中西医结合治疗是中国医学特色疗法和优势手段之一,在心血管疾病领域应用广泛,但在目前研究中,由于中医理论的复杂性和传统统计方法的局限性,针对疾病中医病机规律的客观化推导较少,在一定程度上限制了中医药文化的传承与发展。结构方程模型作为一种具有引入潜在变量、有效处理误差、分析多变量关系等优势的现代化统计方法,能对疾病变量间的复杂因果关系进行客观化分析,以阐明疾病的发病机制。此模型可为中医传统理论提供有力的数据支持,有助于结合现代西医诊疗经验,推进临床中西医结合防治心血管疾病工作的开展。

关键词：结构方程模型中西医结合治疗心血管疾病

维普期刊数据库博看期刊

Catalyst-free,radical-mediated intermolecular 1,2-arylheteroarylation of alkenes by cleaving inert C–C bond

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Science China Chemistry 2021年第10期64卷 1703-1708页

作者： meishan Ji Xinxin Wang Jige Liu Xinxin Wu Chen Zhu Key Laboratory of Organic Synthesis of Jiangsu Province College of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China Key Laboratory of Synthetic Chemistry of Natural Substances Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

A novel photoinduced intermolecular 1,2-arylheteroarylation of alkenes and the efficient synthesis of valuable polyarylalkanes are *** reaction is operationally simple,proceeds under mild conditions and with no additional catalyst and *** strategically designed radical cascade reaction is enabled by electron transfer,and involves cleavage of an inert C–C *** process features broad functional group compatibility as well as high product transformability.

关键词： alkene difunctionalization arylation catalyst-free C–C activation functional group migration radical reactions

茶梗基活性炭的制备及其对水中重金属Cd^(2+)的吸附

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福建技术师范学院学报 2024年第2期42卷 71-78页

作者：林美珊郑虹陈玉池林倩福建技术师范学院材料与包装工程学院福建福清350300 福建技术师范学院食品与生物工程学院福建福清350300 福建技术师范学院近海流域环境测控治理福建省高校重点实验室福建福清350300

以茶梗为原料,通过氯化锌活化-高温炭化法制备茶梗基活性炭,并以静态吸附法去除模拟废水中的Cd^(2+).考察吸附剂用量、Cd^(2+)初始质量浓度、溶液初始pH值等对茶梗基活性炭吸附Cd^(2+)效果的影响;通过红外光谱测定吸附前后的茶梗基活性... 详细信息

以茶梗为原料,通过氯化锌活化-高温炭化法制备茶梗基活性炭,并以静态吸附法去除模拟废水中的Cd^(2+).考察吸附剂用量、Cd^(2+)初始质量浓度、溶液初始pH值等对茶梗基活性炭吸附Cd^(2+)效果的影响;通过红外光谱测定吸附前后的茶梗基活性炭的表面结构、吸附动力学及等吸附温模型拟合,结果表明,茶梗基活性炭对Cd^(2+)的吸附符合准二级动力学模型及Langmuir吸附等温模型.正交实验得出,茶梗基活性炭对Cd^(2+)吸附的最佳实验条件.

关键词：茶梗活性炭 Cd^(2+) 吸附性能

DNA cytosine methylation in plant development

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Journal of Genetics and Genomics 2010年第1期37卷 1-12页

作者： meishan Zhang Josphert N.Kimatu Kezhang Xu Bao Liu Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics and Cytology Northeast Normal UniversityChangchun 130024China Department of Agronomy Jilin Agricultural UniversityChangchun 130118China

Cytosine bases of the nuclear genome in higher plants are often extensively *** methylation has been implicated in the silencing of both transposable elements （TEs） and endogenous genes,and loss of methylation may have severe functional *** recent methylation profiling of the entire Arabidopsis genome has provided novel insights into the extent and pattern of cytosine methylation and its relationships with gene *** addition,the fresh studies also revealed the more dynamic nature of this epigenetic modification across plant development than previously *** methylation of gene promoter regions usually inhibits transcription,but methylation in coding regions （gene-body methylation） does not generally affect gene *** demethylation （though probably act synergistically with passive loss of methylation） of promoters by the 5-methyl cytosine DNA glycosylase or DEMETER （DME） is required for the uni-parental expression of imprinting genes in endosperm,which is essential for seed *** opinion that cytosine methylation is indispensible for normal plant development has been reinforced by using single or combinations of diverse loss-of-function mutants for DNA methyltransferases,DNA glycosylases,components involved in siRNA biogenesis and chromatin remodeling *** of cytosine methylation in plants are usually faithfully maintained across organismal generations by the concerted action of epigenetic inheritance and progressive correction of strayed ***,some variant methylation patterns may escape from being corrected and hence produce novel epialleles in the affected somatic ***,coupled with the unique property of plants to produce germline cells late during development,may enable the newly acquired epialleles to be inherited to future generations,which if visible to selection may contribute to adaptation and evolution.

关键词： DNA cytosine methylation alteration DNA methyltransferase DNA glycosylase chromatin structure imprinting plant development

The influence of rock anisotropy on elliptical-polarization state of inhomogenously refracted P-wave

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Science China(Physics,Mechanics & Astronomy) 2016年第4期59卷 71-77页

作者： Lin Fa Jie Zhao YongLan Han GuoHui Li PengFei Ding meishan Zhao School of Electronic Engineering Xi'an University of Posts and Telecommunications James Franck Institute and Department of Chemistry the University of Chicago

This paper discusses the influence of the anisotropy parameters on elliptical-polarization of the inhomogenously refracted P-wave induced at VTI-media *** this refracted P-wave,we have derived,the equations of the elliptical-polarization *** the elliptical-polarization trajectory,we calculated the effects of the rock anisotropic-parameters on the polarization state,with a Poincare-sphere-like representation,for several varying media *** is noted that the size,shape and initial phase angle of the elliptical-polarization trajectory are all depending the anisotropy media,as well as on the *** expect that the findings from this paper would be applied to practical applications of seismic exploration.

关键词： anisotropy elliptical-polarization inhomogenous wave VTI medium

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协作机器人技术与产业分析

科技和产业 2024年第11期24卷 282-288页

作者：范玫杉刘嘉马伟佳工业和信息化部产业发展促进中心北京100017

随着制造业向智能化、柔性化方向转型,协作机器人作为一种能够与人类共同工作的机器人系统,受到广泛关注和应用。对协作机器人技术与产业发展情况进行综述和分析。回顾协作机器人的发展历程,突出其在现代工业和服务领域的重要性;分析协... 详细信息

随着制造业向智能化、柔性化方向转型,协作机器人作为一种能够与人类共同工作的机器人系统,受到广泛关注和应用。对协作机器人技术与产业发展情况进行综述和分析。回顾协作机器人的发展历程,突出其在现代工业和服务领域的重要性;分析协作机器人的技术发展,包括规划与控制、多模感知技术、机器人技能学习与决策本质安全与人机协作等方面;结合国内外产业发展情况的比较分析,展望技术与产业发展趋势,为协作机器人领域的研究和发展提供参考和启示。

关键词：协作机器人智能化人机协作制造业

APPCorp:a corpus for Android privacy policy document structure analysis

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Frontiers of Computer Science 2023年第3期17卷 1-10页

作者： Shuang LIU Fan ZHANG Baiyang ZHAO Renjie GUO Tao CHEN meishan ZHANG College of Intelligence and Computing Tianjin UniversityTianjin 300372China School of New Media and Communication Tianjin UniversityTianjin 300350China Google Mountain ViewCA 94043USA

With the increasing popularity of mobile devices and the wide adoption of mobile Apps,an increasing concern of privacy issues is *** policy is identified as a proper medium to indicate the legal terms,such as the general data protection regulation(GDPR),and to bind legal agreement between service providers and ***,privacy policies are usually long and vague for end users to read and *** is thus important to be able to automatically analyze the document structures of privacy policies to assist user *** this work we create a manually labelled corpus containing 231 privacy policies(of more than 566,000 words and 7,748 annotated paragraphs).We benchmark our data corpus with 3 document classification models and achieve more than 82%on F1-score.

关键词： privacy policy GDPR document structure analysis representation learning graph neural network