检索结果-南通市图书馆

Transfer Path Contribution to Floor Vibration of Metro Vehicles Based on Operational Transfer Path Analysis Method

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 Journal of Mechanical Engineering 2022年第2期35卷 228-238页

作者： Laixian Peng jian Han Jiaxing nie Xinbiao Xiao Caiying Mi School of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031China Southwest Technology and Engineering Research Institute Chongqing 400039China State Key Laboratory of Traction Power Southwest Jiaotong UniversityChengdu 610031China

Operational transfer path analysis(OTPA)is an advanced vibration and noise transfer path identification and contribution evaluation ***,the application of OTPA to rail transit vehicles considers only the excitation amplitude and ignores the influence of the excitation *** study considers the influence of the excitation amplitude and phase,and analyzes the contribution of the secondary suspension path to the floor vibration when the metro vehicle runs at 60 km/h,using an analysis based on the OTPA *** results show that the vertical direction of the anti-rolling torsion bar area provides the maximum contribution to the floor vibration,with a contribution of 22.1%,followed by the longitudinal vibration of the air spring area,with a contribution of 17.1%.Based on the contribution analysis,a transfer path optimization scheme is proposed,which may provide a reference for the optimization of the transfer path of metro vehicles in the future.

关键词： OTPA Secondary suspension Contribution analysis Transfer path optimization scheme Metro vehicles

Effect of particle type on the shear behaviour of granular materials

在线全文

学校读者我要写书评

暂无评论

Particuology 2021年第3期19卷 124-131页

作者： Shunkai Liu Zhihong nie Wei Hu jian Gong Peng Lei School of Civil Engineering Central South UniversityChangsha 410075China Hunan Province Key Laboratory of Geotechnical Engineering Stability Control and Health Monitoring Hunan University of Science and TechnologyXiangtan 411201China School of Hydraulic Engineering Changsha University of Science and TechnologyChangsha 410114China

In discrete element method(DEM)simulations,multi-sphere(MS)clumped and convex particles are two main particle models that are used to study the mechanical behaviours of granular *** interest is the evaluation of the effect of multiple contacts between clumped particles or single contacts between convex particles on the mechanical behaviours of granular *** this context,a series of drained triaxial compression tests were conducted on convex true(CT)ellipsoids and MS ellipsoids with aspect ratios(ARs)ranging from *** microscale results indicate that at a given AR,the critical friction angleφ_(c)changes with the particle type,whereas the peak friction angleφ_(p)is nearly independent of the particle *** anisotropic analysis provides underlying mechanisms of the shear strength evolution from two ***,the anisotropies of granular materials are essential to shear strength as the deviatoric(q)-to-effective mean(p′)stress ratio can be expressed as the sum of the anisotropies,i.e.,q/p'≈0.4a_(c)+0.4a_(n)+0.6a_(t),where ac,an and at are the normal contact anisotropy,normal contact force anisotropy and tangential contact force anisotropy,*** all samples,a_(c)and a_(n)underpin the shear strength and are influenced by the particle *** similarφ_(p)displayed by the CT and MS ellipsoids does not translate to similar a_(n)and a_(c)but similar a_(c)+a_(n)for the two particle *** addition,owing to their larger a_(c)+a_(n),the CT ellipsoids have a higherφ_(c)than the MS ***,there is a satisfactory linear relationship between q/p'and ac within strong and non-sliding(sn)contacts a_(c)^(sn)(i.e.,q/p′=ka_(c)^(sn)),where k is the fitting ***,in the peak state,the subtle difference in shear strength is attributed to the greater acsn in the CT ellipsoids than in the MS ellipsoids that is counteracted by the smaller ***,in the critical state,the greater difference in a_(c)^(sn)between the CT

关键词： Multi-sphere clump Convex true particle DEM Particle type Anisotropy Shear strength

The surface activation of boron to improve ignition and combustion characteristic

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2022年第9期18卷 1679-1687页

作者： jian Wang Jun Wang Yaofeng Mao Rufang Peng Fude nie State Key Laboratory of Environment-friendly Energy Materials Southwest University of Science and TechnologyNo.59Qinglong RoadMianyang CitySichuan621010China Institute of Chemical Materials China Academy of Engineering PhysicsNo.64Mianshan RoadMianyang CitySichuan621999China

Boron is a very promising and highly attractive fuel because of high calorific value. However, the practical applications in explosives and propellants of boron have been limited by long ignition delay time and low combustion efficiency. Herein, nano-Al and graphene fluoride(GF) as surface activated materials are employed to coat boron(B) particles to improve ignition and combustion performance. The reaction heat of nano-Al coated B/KNO_(3)and GF coated B/KNO_(3)are 1116.83 J/g and 862.69 J/g, respectively, which are higher than that of pure B/KNO_(3)(823.39 J/g). The ignition delay time of B/KNO_(3)could be reduced through nano-Al coating. The shortest ignition delay time is only 75 ms for B coated with nano-Al of 8 wt%, which is much shorter than that of pure B/KNO_(3)(109 ms). However, the ignition delay time of B/KNOcoated with GF has been increased from 109 to 187 ms. B coated with GF and nano-Al shown significantly influence on the pressure output and flame structure of B/KNO_(3). Furthermore, the effects of B/O ratios on the pressure output and ignition delay time have been further fully studied. For B/KNO_(3)coated with nano-Al and GF, the highest pressures are 88 KPa and 59 KPa for B/O ratio of 4:6, and the minimum ignition delay time are 94 ms and 148 ms for B/O ratio of 7:3. Based on the above results, the reaction process of boron coated with GF and nano-Al has been proposed to understand combustion mechanism.

关键词： Boron Surface activation Ignition Pressure output Combustion mechanism

在线全文

学校读者我要写书评

暂无评论

硫铝酸盐水泥基材料抗碳化性能研究进展

硅酸盐通报 2024年第8期43卷 2711-2725页

作者：周健李伟华皮振宇徐名凤李辉聂松河北工业大学土木与交通学院天津300401

碳化是复杂的物理化学过程,主要包括二氧化碳(CO_(2))在水泥混凝土中的扩散、溶解和与可碳化物质的反应,最终造成水泥混凝土碱性的降低和钢筋的锈蚀,显著影响其耐久性能。硫铝酸盐水泥(CSA)具有快硬早强、耐硫酸盐腐蚀性能优异等特点,... 详细信息

碳化是复杂的物理化学过程,主要包括二氧化碳(CO_(2))在水泥混凝土中的扩散、溶解和与可碳化物质的反应,最终造成水泥混凝土碱性的降低和钢筋的锈蚀,显著影响其耐久性能。硫铝酸盐水泥(CSA)具有快硬早强、耐硫酸盐腐蚀性能优异等特点,但其抗碳化性能较差,易导致水泥内部化学组成的改变和微观结构的劣化,最终将严重危害基础设施的正常服役。因此,明晰影响CSA碳化的因素,揭示CSA碳化机理具有重要的工程和科研意义。首先从CSA的水化产物出发,介绍了三硫型水化硫铝酸钙(AFt)、单硫型水化硫铝酸钙(AFm)及水化硅酸钙(C-S-H)的碳化机理;其次分析了材料因素对CSA抗碳化性能的影响;最后综述了CO_(2)矿化养护对CSA性能的提升作用,总结了目前CSA碳化研究的不足,为进一步研究CSA抗碳化性能提升方法和碳化利用方式提出了建议。

关键词：硫铝酸盐水泥碳化机理 AFt AFm C-S-H 耐久性能

维普期刊数据库博看期刊

Electroacupuncture promotes the recovery of motor neuron function in the anterior horn of the injured spinal cord

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2015年第12期10卷 2033-2039页

作者： jian-hui Yang jian-guo Lv Hui Wang Hui-yong nie Rehabilitation Center First Affiliated Hospital of Health Science CenterXi’an Jiaotong University

Acupuncture has been shown to lessen the inflammatory reaction after acute spinal cord injury and reduce secondary ***,the mechanism of action remains *** this study,a rat model of spinal cord injury was established by compressing the T8-9 segments using a modified Nystrom ***-four hours after injury,Zusanli（ST36）,Xuanzhong（GB39）,Futu（ST32）and Sanyinjiao（SP6）were stimulated with *** with spinal cord injury alone were used as *** 2,4 and 6 weeks after injury,acetylcholinesterase（ACh E）activity at the site of injury,the number of medium and large neurons in the spinal cord anterior horn,glial cell line-derived neurotrophic factor（GDNF）m RNA expression,and Basso,Beattie and Bresnahan locomotor rating scale scores were greater in the electroacupuncture group compared with the control *** results demonstrate that electroacupuncture increases ACh E activity,up-regulates GDNF m RNA expression,and promotes the recovery of motor neuron function in the anterior horn after spinal cord injury.

关键词： nerve regeneration spinal cord injury electroacupuncture spine injury secondaryinjury acupoint motor neurons acetylcholinesterase glial cell line-derived neurotrophic factor inclined board test Basso, Beattie and Bresnahan locomotor rating scale functional recovery neuralregeneration

Wernicke's encephalopathy in a rectal cancer patient with atypical radiological features:A case report

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2021年第25期9卷 7600-7604页

作者： Tian nie jian-Li He Department of Neurology The Affiliated Hangzhou First People's HospitalZhejiang University School of MedicineHangzhou 310006Zhejiang ProvinceChina

BACKGROUND Wernicke's encephalopathy is a disease caused by thiamine *** lesions usually involve the periphery of the aqueduct,midbrain,tectum,third ventricle,papillary body,and *** is very rare to affect the vermis and cerebellar *** SUMMARY We report a 77-year-old female patient admitted to the emergency department of our hospital for 2 d of *** magnetic resonance imaging showed increased diffusion weighted imaging signals in the bilateral thalamus,periventricular regions of the third ventricle,corpora quadrigemina,vermis,and cerebellar ***'s encephalopathy was *** was given thiamine therapy and became conscious after the *** Wernicke's encephalopathy may have various imaging *** should keep in mind that Wernicke’s encephalopathy may occur in patients who experience prolonged periods of malnutrition.

关键词： Wernicke's encephalopathy Atypical radiological features Vermis Cerebellar hemispheres Case report

Combining cold sintering and Bi_(2)O_(3)-Activated liquid-phase sintering to fabricate high-conductivity Mg-doped NASICON at reduced temperatures

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materiomics 2019年第2期5卷 237-246页

作者： Haoyang Leng Jiuyuan nie jian Luo Department of NanoEngineering Program of Materials Science and EngineeringUniversity of CaliforniaSan Diego9500 Gilman DriveLa JollaCA92093-0448USA

The cold sintering process(CSP)and Bi_(2)O_(3)-activated liquid-phase sintering(LPS)are combined to densify Mg-doped NASICON(Na_(3.256)Mg_(0.128)Zr_(1.872)Si_(2)PO_(12))to achieve high densities and conductivities at reduced *** an example,a cold-sintered specimen with the addition of 1.1wt%Bi_(2)O_(3)sintering additive achieved a high conductivity of 0.91 mS/cm(with~96%relative density)after annealing at 1000℃;this conductivity is>70%higher than that of a cold-sintered specimen without adding the Bi_(2)O_(3)sintering additive,and it is>700%of the conductivity of a dry-pressed counterpart with the same amount of Bi_(2)O_(3)added,all of which are subjected to the same heating *** highest conductivity achieved in this study via combining CSP and Bi_(2)O_(3)-activated LSP is>1.5 mS/*** study suggests an opportunity to combine the new CSP with the traditional LPS to sinter solid electrolytes to achieve high densities and conductivities at reduced *** combined CSP-LPS approach can be extended to a broad range of other materials to fabricate the“thermally fragile”solid electrolytes or solid-state battery systems,where reducing the processing temperature is often desirable.

关键词： Cold sintering process Liquid-phase sintering NASICON Solid electrolytes Solid-state sodium-ion battery

Buckled Fiber Conductors with Resistance Stability under Strain

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advanced Fiber Materials 2021年第3期3卷 149-159页

作者： Weisen Meng Mingyu nie Zhiyu Liu jian Zhou School of Materials Science and Engineering Sun Yat-Sen University GuangzhouGuangdong 510275China

The availability of fiber conductors that can be stretched to large extents without significantly changing resistance or con-ductivity could enable the advances of elastic conductors as electronic interconnects,electronic skins,stretchable sensors,wearable systems,and medical ***,the preparation of fiber conductors with high stretchability is crucial to the development of flexible electronic *** review summarizes the advances in constructing fiber conductors with an emphasis on recent developments of buckled structural design,fabrication methodologies,and strategies,with the ulti-mate goal of achieving good stability of resistance or conductivity at large *** review classifies the buckled fiber conductors into inner buckling and outer buckling,and related examples are summarized,providing a context that buckled fiber conductors are geared towards applications in electrical interconnects,wearable systems,and smart medical *** present challenges in this area are critically evaluated and our perspectives for improving the performance of the buckled fiber conductors for future applications are presented.

关键词： Buckled Fiber conductor Stretchability Resistance

鹑鸡肠球菌致腹膜透析相关性腹膜炎1例并文献复习

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中华医院感染学杂志 2024年第11期34卷 1668-1671页

作者：王庆芬聂建东唐雯郑佳佳滨州市人民医院肾内科山东滨州256600 北京大学第三医院肾内科北京100191 北京大学第三医院检验科北京100191

目的探讨鹑鸡肠球菌致腹膜透析相关性腹膜炎的临床特点.方法回顾性分析1例鹑鸡肠球菌致腹膜透析相关腹膜炎的临床资料,并文献复习.结果本例患者反复发作腹膜透析相关腹膜炎,腹膜透析液培养致病菌为鹑鸡肠球菌,两种抗菌药物足疗程联... 详细信息

目的探讨鹑鸡肠球菌致腹膜透析相关性腹膜炎的临床特点.方法回顾性分析1例鹑鸡肠球菌致腹膜透析相关腹膜炎的临床资料,并文献复习.结果本例患者反复发作腹膜透析相关腹膜炎,腹膜透析液培养致病菌为鹑鸡肠球菌,两种抗菌药物足疗程联合应用腹膜炎治愈.鹑鸡肠球菌所致腹膜炎较为罕见,易复发且预后不良,必要时需拔除腹膜透析管.结论鹑鸡肠球菌是导致腹膜透析相关性腹膜炎的少见条件致病菌,指南经验性治疗方案未能覆盖此病原体,需及早识别并合理治疗.

关键词：鹑鸡肠球菌腹膜透析相关性腹膜炎持续非卧床腹膜透析