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对恽寿平没骨花鸟画“三期论”的再思考——以恽寿平纪年没骨花鸟画题跋为中心 被引量:1
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作者 方忆 《杭州文博》 2007年第1期79-86+115+87,共10页
恽寿平(1633—1690),原名格,字惟大,一字寿平,后以此字行,更字正叔,号南田,别号云溪外史、东园草衣等,武进(今江苏常州)人。中国绘画史上杰出的画家,清初'六大家'('四王吴恽')之一。他是常州画派的创始人,其诗、书、画... 恽寿平(1633—1690),原名格,字惟大,一字寿平,后以此字行,更字正叔,号南田,别号云溪外史、东园草衣等,武进(今江苏常州)人。中国绘画史上杰出的画家,清初'六大家'('四王吴恽')之一。他是常州画派的创始人,其诗、书、画异曲同工,有'南田三绝'之誉。 展开更多
关键词 寿平 花鸟画 南田 题跋 云溪 外史 常州 字行
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Quantitative estimation of social stock for metals Al and Cu in China 被引量:5
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作者 岳强 王鹤鸣 陆钟武 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第7期1744-1752,共9页
Social stock for metal determines secondary or recoverable resources to a certain extent.Top-down analysis method for the studying of metal in social stock was given.Influences of metal consumption under three circums... Social stock for metal determines secondary or recoverable resources to a certain extent.Top-down analysis method for the studying of metal in social stock was given.Influences of metal consumption under three circumstances,that is keeping constant,varying in a linear trend and in an exponential trend,on one kind of metal’s social stock,recyclable ratio and average age were analyzed.Al-contents and Cu-contents in social stock for China during the period 2006-2009 were calculated.The results reveal that Al-contents and Cu-contents in social stock kept increasing and reached 88.9 million tons and 51.4 millions tons in 2009,respectively,their average recyclable ratios are 1.45% and 0.30%,and the average ages are 4.65 years and 6.89 years,respectively.The recyclable ratios and average ages of Al-contents and Cu-contents in social stock will rise in future along with the decline of the increasing rate of aluminum consumption and copper consumption. 展开更多
关键词 social stock secondary resource average use life recyclable ratio average age
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资寿解语汤治疗中风后失语37例 被引量:7
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作者 张力 《中国中医药现代远程教育》 2013年第6期21-21,共1页
目的观察资寿解语汤治疗中风后失语疗效观察。方法选取2012年3月至2012年11月在我院病房中风失语症患者76例,治疗组37例,对照组39例。治疗组、对照组均采用常规治疗,治疗组加服资寿解语汤治疗3周。结果 AQ评分治疗组总有效率为89.1%,对... 目的观察资寿解语汤治疗中风后失语疗效观察。方法选取2012年3月至2012年11月在我院病房中风失语症患者76例,治疗组37例,对照组39例。治疗组、对照组均采用常规治疗,治疗组加服资寿解语汤治疗3周。结果 AQ评分治疗组总有效率为89.1%,对照组为79.4%。WEB评分后发现治疗组语言功能恢复的效果高于对照组恢复效果。结论资寿解语汤在治疗中风后失语方面有理想的疗效,值得临床推广。 展开更多
关键词 寿平语汤 中风 失语 中医药治疗
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Analysis of anthropogenic aluminum cycle in China 被引量:4
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作者 岳强 王鹤鸣 +1 位作者 陆钟武 智升科 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第4期1134-1144,共11页
Anthropogenic aluminum cycle in China was analyzed by the aluminum flow diagram based on the life cycle of aluminum products. The whole anthropogenic aluminum cycle consists of four stages: alumina and aluminum produ... Anthropogenic aluminum cycle in China was analyzed by the aluminum flow diagram based on the life cycle of aluminum products. The whole anthropogenic aluminum cycle consists of four stages: alumina and aluminum production, fabrication and manufacture, use and reclamation. Based on the investigation on the 2003-2007 aluminum cycles in China, a number of changes can be found. For instance, resources self-support ratio (RSR) in alumina production dropped from 95.42%to 55.50%, while RSR in the aluminum production increased from 52.45%to 79.25%. However, RSR in the Chinese aluminum industry leveled off at 50%in the period of 2003-2007. The respective use ratios of domestic and imported aluminum scrap in the aluminum industry of 2007 were 5.38% and 9.40%. In contrast, both the net imported Al-containing resources and the lost quantity of Al-containing materials in aluminum cycle increased during the same period, as well as the net increased quantity of Al-containing materials in social stock and recycled Al-scrap. Proposals for promoting aluminum cycle were put forward. The import/export policy and reducing the loss of Al-containing materials for the aluminum industry in China in the future were discussed. 展开更多
关键词 ANTHROPOGENIC aluminum cycle in China SFA weighted average method average use life
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Mechanism of Reverse Snapback on I-V Characteristics of Power SITHs with Buried Gate Structure 被引量:1
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作者 王永顺 李海蓉 +1 位作者 吴蓉 李思渊 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第3期461-466,共6页
The reverse snapback phenomena (RSP) on I-V characteristics of static induction thyristors (SITH) are physically researched. The I-V curves of the power SITH exhibit reverse snapback phenomena, and even turn to th... The reverse snapback phenomena (RSP) on I-V characteristics of static induction thyristors (SITH) are physically researched. The I-V curves of the power SITH exhibit reverse snapback phenomena, and even turn to the conducting-state,when the anode voltage in the forward blocking-state is increased to a critical value. The RSP I-V characteristics of the power SITH are analyzed in terms of operating mechanism, double carrier injection effect, space charge effect, electron-hole plasma in the channel, and the variation in carrier lifetime. The reverse snapback mechanism is theoretically pro- posed and the mathematical expressions to calculate the voltage and current values at the snapback point are presented. The computing results are compared with the experiment values. 展开更多
关键词 power static induction thyristor reverse snapback electron-hole plasma LIFETIME injection level
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Mean properties of mesoscale eddies in the Kuroshio recirculation region 被引量:3
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作者 马利斌 王强 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2014年第3期681-702,共22页
Using a 19-year altimetric dataset, the mean properties and spatiotemporal variations of eddies in the Kuroshio recirculation region are examined. A total of 2 001 cyclonic tracks and 1 847 anticyclonic tracks were id... Using a 19-year altimetric dataset, the mean properties and spatiotemporal variations of eddies in the Kuroshio recirculation region are examined. A total of 2 001 cyclonic tracks and 1 847 anticyclonic tracks were identifi ed using a geometry-based eddy detection method. The mean radius was 57 km for cyclonic eddies and was 61 km for anticyclonic eddies, respectively, and the mean lifetime was about 10 weeks for both type eddies. There were asymmetric spatial distributions for eddy generation and eddy termination, which were domain-dependent. Mean eddy generation rates were 2.0 per week for cyclonic eddies and were 1.9 per week for anticyclonic eddies. Both type eddies tended to deform during their lifetime and had different propagation characteristics, which mainly propagated westward and southwestward with velocities 4.0–9.9 cm/s, in the Kuroshio recirculation region. Further discussion illustrates that the eddy westward speed maybe infl uenced by the combined effect of vertical shear of horizontal currents and nonlinearity of eddy. To better understand the evolution of eddy tracks, a total of 134 long-lived tracks(lifetime ≥20 weeks) were examined. Comparison between short-span eddies(lifetime ≥4 weeks and <20 weeks) and long-lived eddies is also conducted and the result shows that the short-span and long-lived eddies have similar time evolution. Finally, eddy seasonal variations and interannual changes are discussed. Correlation analysis shows that eddy activity is sensitive to the wind stress curl and meridional gradient of sea surface temperature on interannual timescales. Besides, the strength and orientation of background fl ows also have impacts on the eddy genesis. 展开更多
关键词 mesoscale eddies spatial distributions temporal variations potential factors
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Mitochondria and the aging heart 被引量:4
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作者 Ketul R Chaudhary Haitham El-Sikhry John M Seubert 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2011年第3期159-167,共9页
The average human life span has markedly increased in modem society largely attributed to advances in medical and therapeutic sciences that have successfully reduced important health risks. However, advanced age resul... The average human life span has markedly increased in modem society largely attributed to advances in medical and therapeutic sciences that have successfully reduced important health risks. However, advanced age results in numerous alterations to cellular and subcellular components that can impact the overall health and function of an individual. Not surprisingly, advanced age is a major risk factor for the development of heart disease in which elderly populations observe increased morbidity and mortality. Even healthy individuals that appear to have normal heart function under resting conditions, actually have an increased susceptibility and vulnerability to stress. This is confounded by the impact that stress and disease can have over time to both the heart and vessels. Although, there is a rapidly growing body of literature investigating the effects of aging on the heart and how age-related alterations affect cardiac function, the biology of aging and underlying mechanisms remain unclear. In this review, we summarize effects of aging on the heart and discuss potential theories of cellular aging with special emphasis on mitoehondrial dysfunction. 展开更多
关键词 AGING HEART MITOCHONDRIA heart diseases reactive oxygen species
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Failure analysis study of railway draw-hook coupler 被引量:2
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作者 Moharram MOHAMMADI Armin RAHMATFAM +1 位作者 Mohammad ZEHSAZ Soran HASSANIFARD 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第4期916-924,共9页
Failure analysis of railway draw-hook coupler was carried out.The nondestructive testing method was undertaken on some failed couplers in service to designate critical areas of a coupler.Draw-Hook coupler is used to c... Failure analysis of railway draw-hook coupler was carried out.The nondestructive testing method was undertaken on some failed couplers in service to designate critical areas of a coupler.Draw-Hook coupler is used to connect with the same hook coupler or automatic coupler.The influence of each connection types on the coupler strength in this study was discussed.A numerical stress analysis using FEM was performed,and many approaches including critical plane approach were carried out on fatigue life prediction of coupler under different conditions.The results of the proposed fatigue criterion and fatigue life predictions,as well as static numerical analysis,are validated with experimental results. 展开更多
关键词 draw-hook coupler multi-axial fatigue critical plane approach life prediction static fracture force
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CIED implantation in elderly patients: a single-center experience
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作者 Nikolay N. ILOV Anatoly A. NECHEPURENKO +3 位作者 Albert M. ABDULKADYROV Damir R. PASKEEV Timur F. ASFANDIYAROV Dmitry G. TARASOV 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2018年第6期460-462,共3页
Thanks to the development of new medical technologies and improvement in medical care the last decades are characterized by the growth of elderly's number. The median age of the world's population is increasing beca... Thanks to the development of new medical technologies and improvement in medical care the last decades are characterized by the growth of elderly's number. The median age of the world's population is increasing because of a decline in birth rates and a 20-year increase in the average life span during the second half of the 20th century. 展开更多
关键词 ARRHYTHMIAS Cardiac implantable electronic device ELDERLY IMPLANTATION
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Energy optimal routing for long chain-type wireless sensor networks in underground mines 被引量:12
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作者 Jiang Haifeng Qian Jiansheng +1 位作者 Sun Yanjing Zhang Guoyong 《Mining Science and Technology》 EI CAS 2011年第1期17-21,共5页
Wireless sensor networks are useful complements to existing monitoring systems in underground mines. They play an important role of enhancing and improving coverage and flexibility of safety monitoring systems.Regions... Wireless sensor networks are useful complements to existing monitoring systems in underground mines. They play an important role of enhancing and improving coverage and flexibility of safety monitoring systems.Regions prone to danger and environments after disasters in underground mines require saving and balancing energy consumption of nodes to prolong the lifespan of networks.Based on the structure of a tunnel,we present a Long Chain-type Wireless Sensor Network(LC-WSN)to monitor the safety of underground mine tunnels.We define the optimal transmission distance and the range of the key region and present an Energy Optimal Routing(EOR)algorithm for LC-WSN to balance the energy consumption of nodes and maximize the lifespan of networks.EOR constructs routing paths based on an optimal transmission distance and uses an energy balancing strategy in the key region.Simulation results show that the EOR algorithm extends the lifespan of a network,balances the energy consumption of nodes in the key region and effectively limits the length of routing paths,compared with similar algorithms. 展开更多
关键词 Wireless sensor network Energy optimal routing Underground mine Lifespan of network
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Potential Reproductive Activity of Callosobruchus subinnotatus Pic. (Coleoptera: Bruchinae), Bambara Groundnut (Vigna subterranea Verd.) Depredator
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作者 Seth Wolali Nyamador] Abla Dela Mondedji +2 位作者 Guillaume Koffivi Ketoh Komina Amevoin Isabelle Adole Glitho 《Journal of Life Sciences》 2016年第3期134-144,共11页
Callosobruchus subinnotatus Pic. (Coleoptera: Bruchinae) is the most important depredator of Bambara groundnut seeds (Vigna subterranea Verd.) in West Africa. In view of an efficient control of its populations, s... Callosobruchus subinnotatus Pic. (Coleoptera: Bruchinae) is the most important depredator of Bambara groundnut seeds (Vigna subterranea Verd.) in West Africa. In view of an efficient control of its populations, some of the biological parameters of C. subinnotatus were determined under laboratory conditions (30 ± 2℃; 72 ± 2% HR; 12h: 12h LD). The results have shown that the mean lifespan of females (11.36±1.85 days) is shorter than that of males (15.14 ±2.4 days). The female lays 80.83% eggs within the first 6 days after her emergence with a mean fecundity of 121.34 ±27.62 eggs. The means egg fertility, survival and adult emergence rates are respectively 96.19±1.45%, 97.72 ± 1.08% and 94.01± 2.14%. The sex ratio is in favor of males with a mean of 0.845 ± 0.08. The monitoring of adult emergence in connection with their reproductive status showed that the offspring of C. subinnotatus consists of two physiotypes, a reproductive type that appears during the first 8 days of emergence with a short development time (28.35± 3.36 days) and a non reproductive type that appears from the 9th day of emergence with a longer development time (37.92 ± 3.92 days). 展开更多
关键词 Callosobruchus subinnotatus Vigna subterranea biological parameters physiotypes.
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Modeling of Transient Thermal Conditions in Cutting
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作者 T. Augspurger F. Klocke +3 位作者 B. Dobbeler M. Brockmann S. Gierlings A. Lima 《Journal of Mechanics Engineering and Automation》 2017年第3期113-119,共7页
The thermal conditions like the temperature distribution and the heat fluxes during metal cutting have a major influence on the machinability, the tool lifetime, the metallurgical structure and thus the functionality ... The thermal conditions like the temperature distribution and the heat fluxes during metal cutting have a major influence on the machinability, the tool lifetime, the metallurgical structure and thus the functionality of the work piece. This in particular applies for manufacturing processes like milling, drilling and turning for high-value turbomachinery components like impellers, combustion engines and compressors of the aerospace and automotive industry as well as energy generation, which play a major role in modern societies. However, numerous analytical and experimental efforts have been conducted in order to understand the thermal conditions in metal cutting, yet many questions still prevail. Most models are based on a stationary point of view and do not include time dependent effects like in intensity and distribution varying heat sources, varying engagement conditions and progressive tool wear. In order to cover such transient physics an analytical approach based on Green's functions for the solution of the partial differential equations of unsteady heat conduction in solids is used to model entire transient temperature fields. The validation of the model is carried out in orthogonal cutting experiments not only punctually but also for entire temperature fields. For these experiments an integrated measurement of prevailing cutting force and temperature fields in the tool and the chip by means of high-speed thermography were applied. The thermal images were analyzed with regard to thermodynamic energy balancing in order to derive the heat partition between tool, chips and workpiece. The thus calculated heat flow into the tool was subsequently used in order to analytically model the transient volumetric temperature fields in the tool. The described methodology enables the modeling of the transient thermal state in the cutting zone and particular in the tool, which is directly linked to phenomena like tool wear and workpiece surface modifications. 展开更多
关键词 Metal cutting infrared thermography heat sources transient temperature fields model based on Green's functions.
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Study of the Alpha-Decay Chain for ^(194)Rn with Relativistic Mean-Field Theory
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作者 SHENG Zong-Qiang GUO Jian-You 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第6期1583-1586,共4页
The structures of the nuclei on the alpha-decay chain of ^194Rn are investigated in the deformed relativistic mean-field theory with the effective interaction TMA. We put an emphasis on the ground state properties of ... The structures of the nuclei on the alpha-decay chain of ^194Rn are investigated in the deformed relativistic mean-field theory with the effective interaction TMA. We put an emphasis on the ground state properties of ^194Rn. The calculated alpha-decay energies and lifetimes are both very close to the experimental data for ^186Pb and ^190Po. For ^194Rn, the deviations are a little large on both the alpha-decay energy and the lifetime. We also calculate the alpha-decay energies for the isotopes 192~208^Rn. The tendency for the change of the alpha-decay energies with neutron number is correctly reproduced in the relativistic mean-field theory (RMF). In general, the RMF theory can give a good description of the alpha decay chain of ^194Rn. 展开更多
关键词 relativistic mean field alpha-decay energy HALF-LIFE binding energy
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Low cycle fatigue behavior of zirconium−titanium−steel composite plate 被引量:1
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作者 Bin-bin ZHOU Peng YU +3 位作者 Le CHANG Chang-yu ZHOU Cheng YE Bo-jun ZHANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第5期1530-1547,共18页
The low cycle fatigue behavior of zirconium−titanium−steel composite plate under symmetrical and asymmetric stress control was studied.The effects of mean stress and stress amplitude on cyclic deformation,ratcheting e... The low cycle fatigue behavior of zirconium−titanium−steel composite plate under symmetrical and asymmetric stress control was studied.The effects of mean stress and stress amplitude on cyclic deformation,ratcheting effect and damage mechanism were discussed in detail.The results show that under symmetric stress control,the forward ratcheting deformation is observed.Under asymmetric stress control,the ratcheting strain increases rapidly with mean stress and stress amplitude increasing.Under high stress amplitude,the influence of mean stress is more significant.In addition,by studying the variation of strain energy density,it is found that the stress amplitude mainly promotes the fatigue damage,while the mean stress leads to the ratcheting damage.In addition,fractographic observation shows that the crack initiates in the brittle metal compound at the interface,and the steel has higher resistance to crack propagation.Finally,the accuracy of life prediction model considering ratcheting effect is discussed in detail,and a high-precision life prediction model directly based on mean stress and stress amplitude is proposed. 展开更多
关键词 zirconium−titanium−steel composite plate low cycle fatigue behavior fatigue damage mean stress ratcheting effect life prediction model
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High-Speed EMU TCMS Design and LCC Technology Research 被引量:2
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作者 Hongwei Zhao Zhiping Huang Ying Mei 《Engineering》 SCIE EI 2017年第1期122-129,共8页
This paper introduces the high-speed electrical multiple unit (EMO) life cycle, including the design, manufacturing, testing, and maintenance stages. It also presents the train control and monitoring system (TCMS)... This paper introduces the high-speed electrical multiple unit (EMO) life cycle, including the design, manufacturing, testing, and maintenance stages. It also presents the train control and monitoring system (TCMS) software development platform, the TCMS testing and verification bench, the EMU driving simulation platform, and the EMU remote data transmittal and maintenance platform. All these platforms and benches combined together make up the EMU life cycle cost (LCC) system. Each platform facilitates EMU LCC management and is an important part of the system. 展开更多
关键词 Electrical multiple unit Train control and monitoring system Train communication network Life cycle cost Development platform Testing bench Simulation Remote data transmittal
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Statistical Properties and Confidence Limits about the Mean Time between the Failures (MTBF) in Failure-free Period Life Test (FFPLT)
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作者 王庆成 《Chinese Quarterly Journal of Mathematics》 CSCD 2001年第1期9-19,共11页
On the basis of strict mathematical description about Failure_Free Period Life Test (FFPLT), the statistical properties of the tests and optimal confidence limit of the parameter are discussed in detail and correspond... On the basis of strict mathematical description about Failure_Free Period Life Test (FFPLT), the statistical properties of the tests and optimal confidence limit of the parameter are discussed in detail and corresponding calculating formulae are found out. 展开更多
关键词 FFPLT MTBF operating characteristic (OC) function expected test time (ETT) maximum likelihood estimation lower confidence limit
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Vehicle survival patterns in China 被引量:12
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作者 HAO Han WANG HeWu +1 位作者 OUYANG MingGao CHENG Fei 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第3期625-629,共5页
The vehicle survival pattern describes the process that the survival ratio of vehicles decreases with the growth of vehicle age. Vehicle average life span and vehicle scrappage intensity are the key features of vehicl... The vehicle survival pattern describes the process that the survival ratio of vehicles decreases with the growth of vehicle age. Vehicle average life span and vehicle scrappage intensity are the key features of vehicle survival patterns and are important for the projection of China's vehicle scrappage and ownership. In this study, we modeled the vehicle survival patterns of nine classifications of vehicles in China by employing the Weibull distribution, and obtained the vehicle survival ratio functions. It is estimated that the average life spans of private passenger vehicles, government and business vehicles, non-operating buses, heavy duty, medium duty and light duty trucks are 14.5, 13.1, 11.5, 12.8, 10.1, and 8 years, respectively. The scrappage intensities of these vehicles are similar. Average life spans of taxis, transit buses and non-transit operating buses are 5, 9, and 5.5 years with the pattern of mandatory scrappage. Vehicle scrappages in China are mainly regulated by the upper limits of vehicle distances traveled specified by the compulsory scrappage standards. 展开更多
关键词 VEHICLE survival pattern average life span scrappage intensity
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Probe stiffness regulates receptor-ligand bond lifetime under force 被引量:3
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作者 ZHANG Yan LüShouQin &LONG Mian 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第5期923-929,共7页
Receptor-ligand bond dissociation under applied force is crucial to elucidate its biological functionality when the molecular bond is usually connected to a mechanical probe. While the impact of probe stiffness, k, on... Receptor-ligand bond dissociation under applied force is crucial to elucidate its biological functionality when the molecular bond is usually connected to a mechanical probe. While the impact of probe stiffness, k, on bond rupture force has recently at- tracted more and more attention, the mechanism of how it affects the bond lifetime, however, remains unclear. Here we quanti- fied the dissociation lifetime of selectin-ligand bond using an optical trap assay with low stiffness ranging from 3.5×10^-3 to 4.7×10^-2 pN/nm. Our results indicated that bond lifetime yielded distinct distributions with different probe stiffness, implying the stochastic feature of bond dissociation. It was also found that the mean lifetime varied with probe stiffness and that the catch bond nature was visualized at k≥3.0×10^-2 pN/nm. This work furthered the understanding of the forced dissociation of se- lectin-ligand bond at varied probe stiffness, which is physiologically relevant to the tethered rolling of leukoeytes under blood flow. 展开更多
关键词 probe stiffness bond lifetime optical trap
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Measurement of the lifetimes of promptly produced Ω_(c)^(0) and Ξ_(c)^(0) baryons 被引量:2
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作者 LHCb Collaboration 《Science Bulletin》 SCIE EI CSCD 2022年第5期479-487,M0003,共10页
A measurement of the lifetimes of theΩ_(c)^(0)andΞ_(c)^(0)baryons is reported using proton-proton collision data at a centre-of-mass energy of 13 TeV,corresponding to an integrated luminosity of 5.4 fb;collected by ... A measurement of the lifetimes of theΩ_(c)^(0)andΞ_(c)^(0)baryons is reported using proton-proton collision data at a centre-of-mass energy of 13 TeV,corresponding to an integrated luminosity of 5.4 fb;collected by the LHCb experiment.TheΩ_(c)^(0)andΞ_(c)^(0)baryons are produced directly from proton interactions and reconstructed in the p K^(-)K^(+)π^(+)nal state.TheΩ_(c)^(0)lifetime is measured to be 276.5±13.4±4.4±0.7 fs,and theΞ_(c)^(0)lifetime is measured to be 148.0±2.3±2.2±0.2 fs,where the first uncertainty is statistical,the second systematic,and the third due to the uncertainty on the D^(0)lifetime.These results con firm previous LHCb measurements based on semileptonic beauty-hadron decays,which disagree with earlier results of a four times shorterΩ_(c)^(0)lifetime,and provide the single most precise measurement of theΩ_(c)^(0)lifetime. 展开更多
关键词 Charmed baryon Flavour physics QCD Lifetime Charm physics LHCB
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An energy-equilibrium model for complex stress effect on fatigue crack initiation 被引量:1
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作者 ZHAO SiCong XIE JiJia +1 位作者 ZHAO AiGuo WU XiaoLei 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第5期916-926,共11页
Based on Tanaka and Mura’s fatigue model and Griffith theory for fracture,an energy-equilibrium model was proposed to explain the complex stress effect on fatigue behavior.When the summation of the elastic strain ene... Based on Tanaka and Mura’s fatigue model and Griffith theory for fracture,an energy-equilibrium model was proposed to explain the complex stress effect on fatigue behavior.When the summation of the elastic strain energy release and the stored strain energy of accumulated dislocations reach the surface energy of a crack,the fatigue crack will initiate in materials.According to this model,for multiaxial stress condition,the orientation of the crack initiation and the initiation life can be deduced from the energy equilibrium equation.For the uniaxial fatigue loading with mean stress,the relation between the maximum stress or the minimum stress and the stress amplitude is in agreement with an ellipse equation on the constant life diagram.If the ratio of the mean stress to stress amplitude is less than a critical value-0.17,and the stress amplitude keeps constant,the fatigue crack initiation life will decrease with the increase of the compress mean stress.In this model,the mean stress does not cause damage accumulation with the fatigue cycles in crack initiation.For this reason,the loading sequence of different load levels would induce the cumulative damage to deviate from the Palmgren-Miner cumulative damage rule.The procedure of estimating the damage under random loading is also discussed. 展开更多
关键词 fatigue initiation mean stress effect multiaxial fatigue Tanaka-Mura model damage accumulation
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