检索结果-南通市图书馆

Applied Mathematics and Mechanics(English Edition) 2005年第8期26卷 963-972页

作者： XIAO yong-gang（肖勇刚） FU Yi-ming（傅衣铭） zha Xu-dong（查旭东） Department of Engineering Mechanics Hunan UniversityChangsha 410082 P. R. China College of Bridge and Structure Engineering Changsha University of Science and Technology Changsha 410076 P. R. China

Based on Reissner plate theory and Hamilton variational principle, the nonlinear equations of motion were derived for the moderate thickness rectangular plates with transverse surface penetrating crack on the two-parameter foundation. Under the condition of free boundary, a set of trial functions satisfying all boundary conditions and crack＇s continuous conditions were proposed. By employing the galerkin method and the harmonic balance method, the nonlinear vibration equations were solved and the nonlinear vibration behaviors of the plate were analyzed. In numerical computation, the effects of the different location and depth of crack, the different structural parameters of plates and the different physical parameters of foundation on the nonlinear amplitude frequency response curves of the plate were discussed.

关键词： moderate thickness rectangular plate elastic foundation crack nonlinear vibration

A green and efficient access to aryl nitriles via an electrochemical anodic oxidation

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2014年第8期25卷 1112-1114页

作者： Jia-Qian Ye Zhen-Lei zha.g Zheng-gen zha Zhi-yong Wang Hefei National Laboratory for Physical Sciences at Microscale CAS Key Laboratory of Soft Matter Chemistry & Collaborative Innovation Center of Suzhou Nano Science and Technology University of Science and Technology of China

The nitrile functionality is a key building block in synthetic chemistry, and has wide applications in pharmaceuticals. However, traditional methodologies for the synthesis of nitriles are limited to harsh reaction conditions. Herein, we report a new and efficient access to aryl nitriles by an electrochemical synthesis. Compared with the conventional synthetic methods, this electrochemical synthesis is more environmentally friendly and easier to handle.

关键词： Eletrochemistry Anodic oxidation Aryl nitrile

An Efficient Palladium-catalyzed Coupling Reaction for the Preparation of Biaryls and Polyaryls

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2003年第1期14卷 13-16页

作者： Zhi yong WANg Zheng gen zha Jia Hai zha.g Ji Hui WU Department of Chemistry University of Science and Technology of ChinaHefei 230026

In the case of Pd(PPh3)4 as catalyst and toluene as reaction solvent, the desired biaryls and polyaryls were synthesized in excellent yield and on a large scale.

关键词： Palladium-catalyst coupling reaction preparation biaryl polyaryl.

Investigation of low water recovery based on gas-water two-phase low-velocity Non-Darcy flow model for hydraulically fractured horizontal wells in shale

在线全文

学校读者我要写书评

暂无评论

Petroleum 2023年第3期9卷 364-372页

作者： yong He Jianjun Wang Xiaoqing Huang Yue Du Xiang Li Wenshu zha Daolun Li PetroChina Zhejiang Oilfield Company Hangzhou310023China University of Science and Technology of China Hefei230027China Department of Applied Mathematics Hefei Technology UniversityHefei230027China

Various mechanisms are employed to interpret the low water recovery during the shale-gas production period,such as extra-trapped water in the fracture network,water imbibition due to osmotic pressure and capillary *** lead to the difficulty of water flow,which could be described by lowvelocity non-Darcy's law known as threshold pressure gradient(TPg).In this paper we firstly employ the low-velocity non-Darcy's law to describe the water flow and use Darcy flow accounting for slip flow and free molecular flow mechanisms to model gas flow in the shale *** sensitive study using numerical simulation shows that the proposed flow model could model the low fracturing liquid recovery and that large pseudo TPg leads to lower fracturing liquid ***,the proposed model would give new insight to model the low water recovery in shale formations.

关键词： Low water recovery Low-velocity non-Darcy flow Pseudo threshold pressure gradient Hydraulically fractured horizontal wells Shale gas

Design and experiment of centralized pneumatic deep precision fertilization device for rice transplanter

在线全文

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2020年第6期13卷 109-117页

作者： Xiantao zha.guozhong zha.g Shijie zha.g Qunxi Hou Yang Wang yong Zhou College of Engineering Huazhong Agricultural UniversityWuhan 430070China Key Laboratory of Agricultural Equipment in Mid-lower Yangtze River Ministry of Agriculture and Rural AffairsWuhan 430070China

To improve the precision of deep fertilization of paddy fields,a six-row centralized pneumatic deep precision fertilization device for a rice transplanter was *** device included a spiral fertilizer distribution system,centralized pneumatic fertilizer delivery system,an opener system,and a fertilization control *** centralized airflow distribution method was used in the fertilizer delivery system to ensure that the airflow in each fertilizer pipe was evenly *** rotational speeds of the power take-off(PTO)and fertilizer shaft were measured synchronously using photoelectric sensors and matched proportionately in real-time using PID closed-loop control algorithms to achieve precise fertilization rates at each working speed of the rice *** were two key considerations in the design of the control system to ensure precise ***,a photoelectric sensor was used to measure the speed of the PTO;the high rotational speed of the PTO could provide a high signal frequency and improve the precision of the measurement of the transplanter’s working ***,the fertilizer shaft speed measurement subprogram was set to sleep for a short period to reduce the vibration caused by the *** the tests of pneumatic fertilizer delivery system,single-factor tests on airflow distribution methods were *** results showed that the coefficient of variation of the airflow speed for the centralized airflow distribution method was 1.67%,which was the least among the coefficients of the three distribution *** the bench tests,the rotational speeds of the fertilizer shaft were set at 10 r/min,20 r/min,30 r/min,and 40 r/*** maximum coefficient of variation of the fertilization consistency in different rows was 1.49%at the rotational speed of 20 r/*** maximum coefficient of variation of the fertilization stability was 2.86%at the rotational speed of 40 r/min,while the average fertilizer amount per lap for ea

关键词： agricultural machinery deep precision fertilization pneumatic variable rate transplanter vibration elimination

Decarboxylative bromination of α,β-unsaturated carboxylic acids via an anodic oxidation

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

Chinese Chemical Letters 2017年第6期28卷 1159-1162页

作者： Mei-Xiang Bi Peng Qian Yu-Kang Wang Zheng-gen zha Zhi-yong Wang Hefei National Laboratory for Physical Sciences at Microscale CAS Key Laboratory of Soft Matter Chemistry and Department of Chemistry & Collaborative Innovation Center of Suzhou Nano Science and TechnologyUniversity of Science and Technology of ChinaHefei 230026 China

A novel bromination of α,β-unsaturated carboxylic acids was developed via a decarboxylation by virtue of a direct anodic *** this method,ammonium bromide was employed as a bromine source and the reaction features tr... 详细信息

关键词： Decarboxylative bromination α β-Unsaturated carboxylic acids Ammonium bromide Anodic oxidation Electro-oxidation

Electrosynthesis of oxadiazoles from benzoylhydrazines

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2013年第9期24卷 780-782页

作者： Huan-Yue Ma Zheng-gen zha Zhen-Lei zha.g Li Meng Zhi-yong Wang Hefei National Laboratory for Physical Sciences at Microscale CAS Key Laboratory of Soft Matter Chemistry and Department of Chemistry Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics University of Science and Technology of China

A highly efficient conformation from facile benzoylhydrazines was developed under electrochemical condition. A variety of oxadiazoles were obtained with good yields by virtue of this new method.

关键词： Oxadiazoles Electrochemical reactions Steric effect

煤矿地下水库技术原创试验平台体系研制及应用

在线全文

学校读者我要写书评

暂无评论

煤炭学报 2024年第1期49卷 100-113页

作者：顾大钊曹志国李井峰吴宝杨张勇蒋斌斌郭强王汉鹏武洋史小萌王路军杨毅查尔晟煤炭开采水资源保护与利用全国重点实验室北京102211 北京低碳清洁能源研究院北京102211 国家能源投资集团有限责任公司北京100011 国能神东煤炭集团有限责任公司陕西榆林719315 山东大学齐鲁交通学院山东济南250061

煤炭是我国主体能源,西部是我国煤炭主产区,矿井水保护利用是煤炭开发面临的重大技术难题。国家能源集团煤炭绿色开采技术研发团队经过20多年持续技术攻关,首创了煤矿地下水库技术,在西部神东矿区推广应用,为矿区开发提供了95%以上用水... 详细信息

煤炭是我国主体能源,西部是我国煤炭主产区,矿井水保护利用是煤炭开发面临的重大技术难题。国家能源集团煤炭绿色开采技术研发团队经过20多年持续技术攻关,首创了煤矿地下水库技术,在西部神东矿区推广应用,为矿区开发提供了95%以上用水,确保了矿区可持续开发。为进一步丰富完善煤矿地下水库理论和技术体系,在西部煤炭主产区不同地质和工况条件下推广应用该技术,保障国家能源安全和水资源安全,研发团队构建了煤矿地下水库原创技术试验平台体系,包括煤炭开采地下水运移与保护综合智能试验平台、多煤层开采煤矿地下水库模拟试验平台、煤矿地下水库坝体结构试验平台、西部深部井工矿井筒施工模拟试验台、地下水库水岩耦合机理试验、水处理工艺集成试验平台、煤矿地下水库冲击试验平台等,能够开展西部矿区不同煤层赋存条件下地下水运移规律、坝体结构参数优化、水库安全稳定性、水岩耦合作用机理、矿井水处理工艺参数优化、垮落岩体垮落冲击对坝体影响等研究,为煤矿地下水库建设、运行和安全提供理论支撑和技术验证。利用上述试验平台,开展了多煤层开采煤矿地下水库稳定性及渗流规律模拟、煤矿地下水库坝体结构安全、煤矿地下水库水岩耦合机理等多项试验研究,相关研究成果已应用于现场工程实践,确保了煤矿地下水库安全稳定运行。

关键词：煤矿地下水库地下水运移坝体结构冲击试验水岩耦合

Multiple Episodes of Zircon growth during Anatectic Metamorphism of Metasedimentary Rocks in Collisional Orogens:Constraints from Felsic granulites in the Bohemian Massif

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2023年第3期34卷 609-639页

作者： guang Yang Ren-Xu Chen yong-Fei Zheng Qiong-Xia Xia yong-Jie Yu Kun Li zhaochu Hu Bing gong Xiang-Ping zha CAS Key Laboratory of Crust-Mantle Materials and Environments School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Center of Excellence for Comparative Planetology Chinese Academy of Sciences(CAS)Hefei 230026China Frontiers Science Center for Planetary Exploration and Emerging Technologies University of Science and Technology of ChinaHefei 230026China State Key Laboratory of geological Processes and Mineral Resources Faculty of Materials Science and ChemistryChina University of GeosciencesWuhan 430078China

Zircon is a key accessary mineral for metamorphic geochronology and geochemical tracing,but it has been a challenge to interpret its complex chemical zoning and age record acquired during multiple episodes of anatectic metamorphism in collisional *** is illustrated by a combined study of petrography,phase equilibrium modeling and metamorphic P-T-t determination for granulites from the Bohemian Massif in the Variscan *** rocks record multiple episodes of zircon growth during anatectic *** started from the compressional heating for prograde metamorphism to high-pressure(HP)to ultrahigh-pressure(UHP)eclogite facies with low degrees of partial ***,they underwent a decompressional stage from UHP eclogite facies to HP granulite facies for dehydration *** were followed by a further decompressional stage either to kyanite granulite facies or to sillimanite granulite facies at ultrahigh-temperature(UHT)*** of zircon growth are linked to specific metamorphic conditions for peritectic reactions on the basis of zoning patterns,trace element signatures,index mineral inclusions in dated domains and textural relationships to coexisting *** results indicate that relict zircon domains are preserved even at UHT granulite facies conditions.A few zircon domains in the kyanite granulite grew during the prograde to peak UHP metamorphism,possibly corresponding to consumption of biotite and plagioclase but growth of *** the decompressional exhumation to the HP granulite-facies,relict or prograde zircon domains were mostly dissolved into anatectic melts produced by muscovite *** zircon grains grew during this transition to the HP granulite-facies in the kyanite granulite and are chemically related to continuous growth of garnet,whereas abundant zircon grains grew subsequently at the UHT granulite facies in the sillimanite granulite and are chemically related to garnet breakdown reactions.A

关键词： ultrahigh-pressure metamorphism ultrahigh-temperature metamorphism felsic granulite zircon continental collision crustal anataxis

Effect of Home Blood Pressure Telemonitoring Plus Additional Support on Blood Pressure Control:A Randomized Clinical Trial

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2023年第6期36卷 517-526页

作者： MENg Wen Wen BAI yong Yi YAN Li ZHENg Wei ZENg Qiang ZHENg Yan Song zha Lin PI Hong Ying SAI Xiao yong The Northern Medical District Chinese PLA General HospitalBeijing 100094China Cardiovascular Department the Second Medical CenterChinese PLA General HospitalBeijing 100853China National Clinical Research Center for geriatric Diseases Chinese PLA General HospitalBeijing100853China Department of Epidemiology and Statistics The Graduate School of the Chinese PLA General HospitalBeijing 100853China Anesthesiology Department the 80th Army Hospital of Chinese PLAWeifang 261021ShandongChina Health Management and Research Institute Chinese PLA General HospitalBeijing100853China Nursing Department Chinese PLA General HospitalBeijing 100853China

Objective Current clinical evidence on the effects of home blood pressure telemonitoring(HBPT)on improving blood pressure control comes entirely from developed ***,we performed this randomized controlled trial to evaluate whether HBPT plus support(patient education and clinician remote hypertension management)improves blood pressure control more than usual care(UC)in the Chinese *** This single-center,randomized controlled study was conducted in Beijing,*** aged 30-75 years were eligible for enrolment if they had blood pressure[systolic(SBP)≥140 mmHg and/or diastolic(DBP)≥90 mmHg;or SBP≥130 mmHg and/or DBP≥80 mmHg with diabetes].We recruited 190 patients randomized to either the HBPT or the UC groups for 12 *** primary endpoints were blood pressure reduction and the proportion of patients achieving the target blood *** Totally,172 patients completed the study,the HBPT plus support group(n=84),and the UC group(n=88).Patients in the plus support group showed a greater reduction in mean ambulatory blood pressure than those in the UC *** plus support group had a significantly higher proportion of patients who achieved the target blood pressure and maintained a dipper blood pressure pattern at the12th week of ***,the patients in the plus support group showed lower blood pressure variability and higher drug adherence than those in the UC *** HBPT plus additional support results in greater blood pressure reduction,better blood pressure control,a higher proportion of dipper blood pressure patterns,lower blood pressure variability,and higher drug adherence than *** development of telemedicine may be the cornerstone of hypertension management in primary care.

关键词： Hypertension Telemonitoring Blood pressure control Additional support