检索结果-南通市图书馆

An Isolable Phosphinogermylyne as a Synthon of One-Coordinate GeⅠRadical

Chinese Journal of Chemistry 2024年第7期42卷 736-742页

作者： dongmin wang Haonan Chen Yuhao He Xiaodan Chen Li Zhang Gengwen Tan Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education Guangdong Basic Research Center of Excellence for Functional Molecular EngineeringSchool of ChemistryIGCMESun Yat-Sen UniversityGuangzhouGuangdong 510275China School of Electronic Engineering Guangxi Universityof Science and TechnologyLiuzhouGuangxi 545000China College of Chemistry and Material Jinan UniversityGuangzhouGuangdong 510632China Innovation Center for Chemical Science College of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhouJiangsu 215123China Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education Hangzhou Normal UniversityHangzhouZhejiang 311121China

Reduction of chlorogermylene MsFluindtBu-GeCl 1 with potassium graphite(KC8)afforded putative germylyne radical MsFluindtBu-Ge 2 as confirmed by electron paramagnetic resonance(EPR)spectroscopy.However,it slowly decayed via C—H bond activation at the fluorenyl moiety to yield a bis(germylene)3 at room temperature.By using a Lewis base to stabilize the unoccupied p orbital at the GeⅠradical center,acyclic two-coordinate GeⅠradicals MsFluindtBu-Ge(IMe4)4(IMe4=1,3,4,5-tetramethyl-imidazolin-2-ylidene),MsFluindtBu-Ge(IiPr)5(IiPr=1,3-diisopropyl-4,5-dimethyl-imidazolin-2-ylidene),MsFluindtBu-Ge(PMe3)6 were isolated in crystalline forms.The unpaired electron in 4-6 mainly resides at the Ge 4p orbital as revealed by EPR spectroscopic studies and theoretical calculations.Interestingly,facile ligand exchange of PMe3 in 6 with IMe4 and IiPr was observed to afford 4 and 5,respectively.Moreover,phosphinogermylyne 6 reacted with PhEEPh(E=S,Se),4-tetrabutylphenylacetylene(Ar'CCH),[CpMo(CO)3]2 and nBu3SnH to furnish germylenes MsFluindtBu-GeEPh(E=S 7,Se 8),MsFluindtBu-GeCH=CHAr'9,a germylyne complex MsFluindtBu-Ge≡Mo(CO)2Cp 10 and a Ge(Ⅳ)compound MsFluindtBu-GeH2SnnBu311,respectively.The reactivity studies demonstrate that 6 can act as a synthon of one-coordinate germylyne radical attributing to labile coordination of trimethylphosphine.

关键词： Phosphinogermylyne Germanium Radicals Donor-acceptor systems Radical reactions

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Numerical Stability and Accuracy of Contact Angle Schemes in Pseudopotential Lattice Boltzmann Model for Simulating Static Wetting and Dynamic Wetting

引用

Computer Modeling in Engineering & Sciences 2023年第10期137卷 299-318页

作者： dongmin wang Gaoshuai Lin Key Laboratory of Multiphase Flow and Heat Transfer in Shanghai Power Engineering School of Energy and Power EngineeringUniversity of Shanghai for Science and TechnologyShanghai200093China Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application Suzhou University of Science and TechnologySuzhou215009China

There are five most widely used contact angle schemes in the pseudopotential lattice Boltzmann(LB)model for simulating the wetting phenomenon:The pseudopotential-based scheme(PB scheme),the improved virtualdensity scheme(IVD scheme),the modified pseudopotential-based scheme with a ghost fluid layer constructed by using the fluid layer density above the wall(MPB-C scheme),the modified pseudopotential-based scheme with a ghost fluid layer constructed by using the weighted average density of surrounding fluid nodes(MPB-W scheme)and the geometric formulation scheme(GF scheme).But the numerical stability and accuracy of the schemes for wetting simulation remain unclear in the past.In this paper,the numerical stability and accuracy of these schemes are clarified for the first time,by applying the five widely used contact angle schemes to simulate a two-dimensional(2D)sessile droplet on wall and capillary imbibition in a 2D channel as the examples of static wetting and dynamic wetting simulations respectively.(i)It is shown that the simulated contact angles by the GF scheme are consistent at different density ratios for the same prescribed contact angle,but the simulated contact angles by the PB scheme,IVD scheme,MPB-C scheme and MPB-W scheme change with density ratios for the same fluid-solid interaction strength.The PB scheme is found to be the most unstable scheme for simulating static wetting at increased density ratios.(ii)Although the spurious velocity increases with the increased liquid/vapor density ratio for all the contact angle schemes,the magnitude of the spurious velocity in the PB scheme,IVD scheme and GF scheme are smaller than that in the MPB-C scheme and MPB-W scheme.(iii)The fluid density variation near the wall in the PB scheme is the most significant,and the variation can be diminished in the IVD scheme,MPB-C scheme andMPBWscheme.The variation totally disappeared in the GF scheme.(iv)For the simulation of capillary imbibition,the MPB-C scheme,MPB-Wscheme and GF scheme simulate the dynamics of the liq

关键词： Pseudopotential lattice Boltzmann model contact angle scheme static wetting dynamic wetting capillary imbibition

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Triplet bismuthinidenes featuring unprecedented giant and positive zero field splittings

引用

National Science Review 2023年第10期10卷 79-85页

作者： Mengyuan Wu wang Chen dongmin wang Yizhen Chen Shengfa Ye Gengwen Tan Innovation Center for Chemical Sciences Key Laboratory of Organic Synthesis of Jiangsu ProvinceCollege of ChemistryChemical Engineering and Materials Science Soochow University State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education School of ChemistryIGCME Sun Yat-sen University State Key Laboratory of Elemento-Organic Chemistry Nankai University

Isolation of triplet pnictinidenes,which bear two unpaired electrons at the pnictogen centers,has long been a great challenge due to their intrinsic high reactivity.Herein,we report the syntheses and characterizations of two bismuthinidenes MsFluindtBu-Bi(3) and MsFluind*-Bi(4) stabilized by sterically encumbered hydrindacene ligands.They were facilely prepared through reductions of the corresponding dichloride precursors with 2 molar equivalents of potassium graphite.The structural analyses revealed that 3 and 4contain a one-coordinate bismuth atom supported by a Bi-C single σ bond.As a consequence,the remaining two Bi 6p orbitals are nearly degenerate,and 3 and 4 possess triplet ground states.Experimental characterizations with multinuclear magnetic resonance,magne tome try and near infrared spectroscopy coupled to wavefunction based ab initio calculations concurred to evidence that there exist giant and positive zero field splittings(>4300 cm-1) in their S=1 ground states.Hence even at room temperature the systems almost exclusively populate the lowest-energy nonmagnetic Ms=0 level,which renders them seemingly diamagnetic.

关键词： bismuth bismuthinidene triplet state zero field splitting theoretical calculation

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

The Distribution and Potential Exposure Factors of Physical Activity Level Among Middle-Aged and Elderly Population—Six Communities,Beijing,China,October 2020 to January 2021

引用

China CDC weekly 2022年第27期4卷 593-600页

作者： Heming Pei Ning Kang Fan Yang Xinming Song Gong Chen dongmin wang Institute of Population Research/Institute on Aging Peking UniversityBeijingChina Department of Physical Education Peking UniversityBeijingChina.

Summary What is already known about this topic?Available evidence suggested that 31%of the world’s population do not meet the minimum recommendations for physical activity.What is added by this report?The latest findings showed that physical activity level(PAL),metabolic equivalents(MET)in min/week with<4,500(low),4,500–6,000(moderate)and≥6,000(high)accounted for 45.72%,25.62%,and 28.66%of middle-aged and elderly population in Changchunyuan Community,Weixiuyuan Community,Zhongguanyuan Community,Yanbeiyuan Community,Kangzeyuan Community,and Xima Community,respectively.The moderate and high PAL was associated with a decreased risk of hypertension,cardiovascular disease,dyslipidemia,and poor sleep.What are the implications for public health practice?More attention should be given to the middle-aged population who may be at high risk of insufficient physical activity in urban environments as it is of public health significance for improving the community population health.

关键词： Population Beijing Middle

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Association Between Physical Activity and Physical Fitness Among Adults Aged 40 to 79 Years—Beijing,China,2020–2021

引用

China CDC weekly 2022年第42期4卷 936-940页

作者： Xiaojin Yan Heming Pei Yalu Zhang Ning Kang Gong Chen dongmin wang Institute of Population Research Peking UniversityBeijingChina Department of Physical Education Peking UniversityBeijingChina

Summary What is already known about this topic?Physical fitness is well documented to be associated with physical activity among adults in the United States.In China,research on this association places a heavier emphasis on the populations of children and adolescents.What is added by this report?Physical fitness was shown to be positively associated with physical activity among adults aged 40 to 79 years in China.In populations with lower levels of physical fitness,this association was stronger.The coefficients of the log-transformed metabolic equivalent value of physical activity(logPA)in quantile regression models at the 25th,50th,75th,and 90th percentile of the physical fitness indicators were 1.14,1.04,0.89,and 0.84,respectively.

关键词： Physical logP transformed

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Functional outcomes of Tai Chi exercise prescription in women with knee osteoarthritis

引用

Sports Medicine and Health Science 2022年第4期4卷 239-244页

作者： Ning Kang Yi wang Gong Chen Chao Guo Zhanjia Zhang Donghui Mei Nancy Morrow-Howell dongmin wang Institute of Population Research Peking UniversityNo.5 Yiheyuan Road Haidian DistrictBeijing100871China University of Iowa School of Social Work 225B North HallIowa CityIA52242USA Department of Physical Education Peking UniversityNo.5 Yiheyuan Road Haidian DistrictBeijing100871China Capital Normal University 105 West Third Ring Road NorthHaidian DistrictBeijing100048China Washington University in St.Louis Brown SchoolOne Brookings DriveCampus Box 1196St.LouisMO63130USA

Knee Osteoarthritis(KOA)is the most common type of knee joint injury and also a risk factor for multiple health consequences and is prevalent among older women.The updated clinical guidelines for KOA treatment by the American Rheumatism Association recommend Tai Chi exercise.However,a literature review outlined limitations in Tai Chi intervention implementations.This study aimed to address some of the gaps.This study selected thirty female patients to participate in Tai Chi exercises and undergo relevant tests.The subjects were randomly assigned to Tai Chi or education groups.Independent sample t-tests were conducted to compare the difference in health indicators between the two groups after the intervention.The difference-in-differences(DID)regression was performed to assess the difference in the health outcomes between the two groups at baseline and follow-up and the difference in the differences.After the completion of the intervention,the Tai Chi group reported significantly improved KOA symptoms,physical fitness,and health status indicators than the control group.Specifically,the group differences were significantly larger at the baseline than at the follow-up.Our findings provide compelling evidence of the effects of the innovative Tai Chi exercise prescription specifically designed for KOA patients.The empirical evidence on its effectiveness in alleviating KOA symptoms and improving the overall health of middle-aged and elderly women with KOA suggested that Tai Chi intervention exercise has huge prospects for integration in KOA rehabilitation therapy.

关键词： Tai Chi KOA Intervention Exercise prescription

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Roles of hydroxyl and oxygen vacancy of CeO_(2)·xH_(2)O in Pd-catalyzed ethanol electro-oxidation

引用

Science China Chemistry 2022年第5期65卷 877-884页

作者： Zhenyu Li Jiefei Li Zexuan Zheng Kunhong Jiang Tianrun Zheng dongmin wang Hang Wei Zhiming Shi Xiaotian Li Haibin Chu College of Chemistry and Chemical Engineering Inner Mongolia Engineering and Technology Research Center for Catalytic Conversion and Utilization of Carbon Resource MoleculesInner Mongolia UniversityHohhot 010021China College of Materials Science and Engineering Jilin UniversityChangchun 130022China College of Chemistry Jilin UniversityChangchun 130012China State Key Laboratory of Luminescence and Applications Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China

In the field of noble metal-catalyzed alcohol electro-oxidation reaction(AOR),huge attention is paid on the composition,size,facet,and structure of the metals,while the support engineering should also be emphasized.CeO_(2)has been widely used as a unique support in AOR,primarily due to its abundant oxygen vacancies(O_(v)).Herein,we report CeO_(2)·xH_(2)O nanoparticles with both massive hydroxyl groups(OH)and O_(v)remarkably enhance the catalytic activity and stability of Pd toward ethanol oxidation reaction(EOR).The CO striping experiments and density functional theory(DFT)calculations suggest that OH and O_(v)on CeO_(2)·xH_(2)O surface bring about a large downshift of Pd d-band center and a significant weakening of CO absorption on Pd.Moreover,OH and O_(v)also play synergic roles in the removal of toxic intermediates.Consequently,the important roles of OH and O_(v)of CeO_(2)·xH_(2)O are confirmed in Pd-catalyzed EOR.The facile CeO_(2)·xH_(2)O-enhanced strategy can contribute to the catalyst design for other energy conversion reactions.

关键词： electrocatalysis ceria hydroxyl oxygen vacancy ethanol oxidation reaction

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Fall Injuries and Depressive Symptoms Among Older Adults and the Mediating Effects of Social Participation—China,2011–2018

引用

China CDC weekly 2021年第40期3卷 837-841页

作者： Yalu Zhang Lei Zhang Xinhui Zhang Jingjing Sun dongmin wang Gong Chen Institute of Population Research Peking UniversityBeijingChina Department of Physical Education Peking UniversityBeijingChina.

Summary What is already known on this topic?Prior studies found that fall events were associated with a higher level of depressive symptoms and a lower level of social functioning and social participation.In addition,social participation has also been significantly associated with better conditions of depressive symptoms.What is added by this report?

关键词： participation Effects symptoms

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

芝麻脱皮对芝麻香油自然沉降过程的影响

引用

中国油脂 2024年第1期49卷 1-6页

作者：贾冕王动民刘华敏汪学德冯成王雪雅河南工业大学粮油食品学院郑州450001 驻马店顶志食品有限公司河南驻马店463000

在芝麻香油精制过程中,自然沉降规律受诸多因素影响,为探索提升芝麻香油精制效率的技术手段,以脱皮和未脱皮芝麻所得芝麻香油为研究对象,通过测定芝麻原油与沉淀物组成,并结合沉降过程中沉淀物含量、磷脂含量、酸值、过氧化值、沉淀物... 详细信息

在芝麻香油精制过程中,自然沉降规律受诸多因素影响,为探索提升芝麻香油精制效率的技术手段,以脱皮和未脱皮芝麻所得芝麻香油为研究对象,通过测定芝麻原油与沉淀物组成,并结合沉降过程中沉淀物含量、磷脂含量、酸值、过氧化值、沉淀物压缩速度的变化规律,考察芝麻脱皮对芝麻香油自然沉降过程的影响。结果表明:相比未脱皮芝麻香油,脱皮芝麻香油在线性沉降阶段的沉降效率高约5百分点;芝麻香油沉淀物的90%以上是粗脂肪,还有少量水分、磷脂、蛋白质、糖形成的胶杂,水和磷脂发生明显聚集;沉淀物的酸值远高于芝麻香油,但过氧化值变化不明显;芝麻香油磷脂含量与沉淀物含量变化呈现相似的趋势,上、下层油中磷脂含量和酸值在线性沉降阶段后差异较小;脱皮芝麻香油沉淀物初始高度远低于未脱皮芝麻香油,且在线性沉降阶段压缩速度快于未脱皮芝麻香油,最终成品油得率高于未脱皮芝麻香油约3百分点。综上,脱皮有利于芝麻香油的自然沉降以及获得更高的得率。

关键词：芝麻脱皮芝麻香油沉降磷脂过氧化值酸值

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Roles of hydroxyl and oxygen vacancy of CeO;·xH;O in Pd-catalyzed ethanol electro-oxidation

引用

Science China Chemistry 2022年

作者： Zhenyu Li Jiefei Li Zexuan Zheng Kunhong Jiang Tianrun Zheng dongmin wang Hang Wei Zhiming Shi Xiaotian Li Haibin Chu College of Chemistry and Chemical Engineering Inner Mongolia Engineering and Technology Research Center for Catalytic Conversion and Utilization of Carbon Resource Molecules Inner Mongolia University College of Materials Science and Engineering Jilin University College of Chemistry Jilin University State Key Laboratory of Luminescence and Applications Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences

In the field of noble metal-catalyzed alcohol electro-oxidation reaction（AOR）, huge attention is paid on the composition, size,facet, and structure of the metals, while the support engineering should also be emphasized. CeO;has been widely used as an unique support in AOR, primarily due to its abundant oxygen vacancies（Ov）. Herein, we report CeO;·xH;O nanoparticles with both massive hydroxyl groups（OH） and Ovremarkably enhance the catalytic activity and stability of Pd toward ethanol oxidation reaction（EOR）. The CO striping experiments and density functional theory（DFT） calculations suggest that OH and Ov on CeO;·xH;O surface bring about a large downshift of Pd d-band center and a significant weakening of CO absorption on Pd.Moreover, OH and Ovalso play synergic roles in the removal of toxic intermediates. Consequently, the important roles of OH and Ovof CeO;·xH;O are confirmed in Pd-catalyzed EOR. The facile CeO;·xH;O-enhanced strategy can contribute to the catalyst design for other energy conversion reactions.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：