检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

典型粘结剂对HMX热分解特性影响规律研究

化工新型材料 2024年第4期52卷 146-151页

作者：张霁洋贾月韩志伟王靖岩李亚宁张岩南京理工大学化学与化工学院南京210094 北京航天试验技术研究所北京100048

为研究粘结剂对奥克托今(HMX)热分解特性的影响规律,选取聚胺酯(TPU)和氟橡胶(FR)作为典型粘结剂,基于热分析、气质实验,分析TPU和FR对HMX热分解特性的影响及作用机制。结果表明,相较HMX,HMX/TPU的主要放热历程延长8.2%~37.9%,分解速率... 详细信息

为研究粘结剂对奥克托今(HMX)热分解特性的影响规律,选取聚胺酯(TPU)和氟橡胶(FR)作为典型粘结剂,基于热分析、气质实验,分析TPU和FR对HMX热分解特性的影响及作用机制。结果表明,相较HMX,HMX/TPU的主要放热历程延长8.2%~37.9%,分解速率降低,放热量减少;HMX/FR的主要放热历程缩短0~13.8%,分解速率大于HMX/TPU。TPU和FR均会降低HMX的活化能,HMX/TPU的活化能在转化率为0.6时接近最大值,随后几乎稳定在最大值;而HMX/FR的活化能在转化率为0.4时最大,随后迅速降低。从中间产物来看,TPU既会减少大分子中间产物,抑制HMX分解,也会减少—CH_(2)O、—N_(2)O、—NO、—CO_(2)等小分子产物,降低放热量;而FR会增加大分子中间产物,促进HMX分解,进而增加小分子产物,提高放热量。

关键词：粘结剂奥克托今热分解特性分解历程分解产物

Modified graphene as novel lubricating additive with high dispersion stability in oil

在线全文

学校读者我要写书评

暂无评论

Friction 2021年第1期9卷 143-154页

作者： Pu WU Xinchun CHEN Chenhui zhang Jiping zhang Jianbin LUO jiyang zhang State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China Tianjin Research Institute for Advanced Equipment Tsinghua UniversityTianjin 300300China Beijing Key Laboratory of Long-life Technology of Precise Rotation and Transmission Mechanisms Beijing Institute of Control EngineeringBeijing 100094China

Graphene is a promising material as a lubricant additive for reducing friction and ***,a dispersing method which combines chemical modification of graphene by octadecylamine and dicyclohexylcarbodiimide with a kind of effective dispersant has been successfully developed to achieve the remarkable dispersion stability of graphene in base *** stable dispersion time of modified graphene(0.5 wt%)with dispersant(1 wt%)in PAO-6 could be up to about 120 days,which was the longest time reported so *** the same time,the lubricant exhibits a significant improvement of tribological performance for a steel ball to plate tribo-system with a normal load of 2 *** coefficient of friction between sliding surfaces was~0.10 and the depth of wear track on plate was~21 nm,which decreased by about 44%and 90%when compared to pure PAO-6,***,the analysis of the lubricating mechanisms in regard to the sliding-induced formation of nanostructured tribo-film has been contacted by using Raman spectra and TEM.

关键词： modified graphene dispersity lubricant additives tribo-film

自贸区对地区经济的促进效应研究——基于地级市层面的多期双重差分法研究

在线全文

学校读者我要写书评

暂无评论

对外经贸 2024年第4期 89-93页

作者：赵颖张冀洋孙昕妍新疆大学经济与管理学院新疆乌鲁木齐830000

自由贸易试验区是我国基于国内国际双循环背景下开展的新一轮改革开放“试验田”,其对促进地区经济发展和对外开放有着重要意义。探究自贸区设立对地区经济的促进效应研究,基于280个中国地级市2009—2019年度面板数据,以地区生产总值作... 详细信息

自由贸易试验区是我国基于国内国际双循环背景下开展的新一轮改革开放“试验田”,其对促进地区经济发展和对外开放有着重要意义。探究自贸区设立对地区经济的促进效应研究,基于280个中国地级市2009—2019年度面板数据,以地区生产总值作为测度指标,通过多期双重差分法进行自贸区政策对地区经济影响的分析,并采用安慰剂检验以及反事实检验从不同角度进行稳健性检验。通过实证研究发现:整体而言,自贸区政策能有效推动地区经济正向发展,且这一结果是稳健的。此后应进一步充分发挥自贸区政策的辐射效应,重视创新,各区经济政策出台应更加快速灵活,以匹配其经济高速发展,加大开放制度建设。

关键词：自贸区经济增长双重差分法

在线全文

学校读者我要写书评

暂无评论

基于灰色关联分析的断层突水阶段化感知方法

中国安全科学学报 2024年第7期34卷 63-70页

作者：孙文斌张纪扬王晓杨辉樊建聪 ABDUMALIK Olimov 山东科技大学能源与矿业工程学院山东青岛266590 山东科技大学计算机科学与工程学院山东青岛266590 塔吉克斯坦冶金学院地质与油气工程系塔吉克斯坦苦盏735730

为提升煤矿断层水害感知水平,提出一种以断层活化演变机制和关键控制因素识别的断层突水阶段化感知方法,通过断层突水演化过程相似模拟试验研究工作面底板与断层破坏的演化特征,以底板破坏带应力、断层裂隙带应力、导水通道内水压等为... 详细信息

为提升煤矿断层水害感知水平,提出一种以断层活化演变机制和关键控制因素识别的断层突水阶段化感知方法,通过断层突水演化过程相似模拟试验研究工作面底板与断层破坏的演化特征,以底板破坏带应力、断层裂隙带应力、导水通道内水压等为阶段监测参数,揭示各监测参数与涌水量变化的阶段特征;结合灰色关联性分析法,判定断层突水阶段转化的关键控制因素,进而根据断层突水分析与研究过程,提出断层突水阶段化感知方法。结果表明:底板破坏带、断层裂隙带的应力,导水通道内的水压等监测参数的数值变化特征在断层活化突水过程中呈现出明显的阶段特征,控制因素与涌水量的灰色关联度排序为:底板破坏带应力>断层裂隙带应力>导水通道水压,通过对关键控制因素的识别,可实现断层突水阶段的感知,揭示基于灰色关联分析的感知方法在原理上具备可行性。

关键词：灰色关联性分析断层突水阶段化感知关键控制因素相似模拟试验

Use of stem cell transplantation to treat epilepsy A Web of Science-based literature analysis

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2012年第33期7卷 2624-2631页

作者： Zhongmin Yin Yushu Dong jiyang zhang Li Wang Department of Neurosurgery Chinese PLA 463 Hospital Shenyang 110042 Liaoning Province China Department of Rehabilitation Third Affiliated Hospital of Liaoning Medical University Jinzhou 121000 Liaoning Province China

OBJECTIVE： To identify global research trends in the use of stem cell transplantation to treat epilepsy. DATA RETRIEVAL： We performed a bibliometric analysis of studies on the use of stem cell transplantation to treat epilepsy during 2002–2011, retrieved from Web of Science, using the key words epilepsy or epileptic or epilepticus or seizure and ＂stem cell＂. SELECTION CRITERIA： Inclusion criteria：（a） peer-reviewed published articles on the use of stem cell transplantation to treat epilepsy indexed in Web of Science; （b） original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial material, and news items. MAIN OUTCOME MEASURES：（a） Annual publication output; （b） type of publication; （c） publication by research field; （d） publication by journal; （e） publication by author; （f） publication by country and institution; （g） publications by institution in China; （h） most-cited papers; and （i） papers published by Chinese authors or institutions. RESULTS： A total of 460 publications on the use of stem cell transplantation to treat epilepsy were retrieved from Web of Science, 2002–2011. The number of publications gradually increased over the 10-year study period. Articles and reviews constituted the major types of publications. More than half of the studies were in the field of neuroscience/neurology. The most prolific journals for this topic were Epilepsia, Bone Marrow Transplantation, and Journal of Neuroscience. Of the 460 publications, almost half came from American authors and institutions; relatively few papers were published by Chinese authors or institutions. CONCLUSION： Literature on stem cell transplantation for epilepsy includes many reports of basic research, but few of clinical trials or treatments. Exact effects are not yet evaluated. Epilepsy rehabilitation is a long-term, complex, and comprehensive system engineering. With advances in medical development, some effective medical, social and educational measures are neede

关键词： epilepsy seizure hippocampus stem cell ancestral cell neurons neurogenesis central nervoussystem brain bibliometric neural regeneration

Application of Ultrasonic Motor to Control of Moment Gyroscope Gimbal Servo System

在线全文

学校读者我要写书评

暂无评论

Transactions of Nanjing University of Aeronautics and Astronautics 2017年第1期34卷 15-21页

作者： Wu Jintao Pan Song Zhao Lei Wu Dengyun zhang jiyang Beijing Institute of Control Engineering Beijing 100190P.R.China Precision Driving Laboratory Nanjing University of Aeronautics and AstronauticsNanjing 210016P.R.China

Attitude control system is one of the most important subsystems in a *** a key actuator,the control moment gyroscope(CMG)mainly determines the performance of attitude control ***,the control accuracy and output torque smoothness of the CMG depends more on its gimbal servo *** the constraints of size,mass and power consumption for a small satellite,here,a mini-CMG is designed,in which the gimbal servo system is driven by an ultrasonic *** good performances of the CMG are obtained by both the ultrasonic motor and the rotary *** direct drive of gimbal improves its dynamic performance,with the output bandwidth above 20 *** angular and speed closed-loop control obtains the 0.02°/s gimbal rate,and the output torque resolution better than 2×10^(-3) N·*** ultrasonic motor provides 1.0N·m self-lock torque during power-off,with 12arc-second position accuracy.

关键词： control moment gyroscope gimbal servo system ultrasonic motor

在线全文

学校读者我要写书评

暂无评论

高压氢气下橡胶密封圈的密封性能研究进展

橡胶工业 2024年第9期71卷 712-719页

作者：刘威邹华张继阳王书奇北京化工大学材料科学与工程学院先进弹性体材料研究中心北京100029 北京北化新橡特种材料科技股份有限公司北京100029

综述高压氢气下橡胶密封圈的密封性能研究进展,重点介绍氢气在橡胶中的渗透性能和高压氢气下橡胶密封圈密封失效的影响因素以及高压氢气下橡胶密封圈的密封性能分析方法。氢气在橡胶中的渗透性能影响因素为填料种类、氢气压力、橡胶种类... 详细信息

综述高压氢气下橡胶密封圈的密封性能研究进展,重点介绍氢气在橡胶中的渗透性能和高压氢气下橡胶密封圈密封失效的影响因素以及高压氢气下橡胶密封圈的密封性能分析方法。氢气在橡胶中的渗透性能影响因素为填料种类、氢气压力、橡胶种类,高压氢气下橡胶密封圈密封失效的影响因素主要为泄爆效应和体积膨胀,高压氢气下橡胶密封圈的密封性能分析方法主要包括原位可视化分析和有限元分析。高压氢气密封用橡胶密封圈未来的研究方向是扩展填料和橡胶种类,开发系统性研究和测试设备。

关键词：高压氢气橡胶密封圈渗透性能泄爆效应体积膨胀密封性能

How to improve superlubricity performance of diketone at steel interface:Effects of oxygen gas

在线全文

学校读者我要写书评

暂无评论

Friction 2023年第6期11卷 927-937页

作者： Yuanyuan JIANG Lei CHEN Chen XIAO Shumin zhang Chenhui zhang Ningning ZHOU Tao QIN Linmao QIAN jiyang zhang Tribology Research Institute State Key Laboratory of Traction PowerSouthwest Jiaotong UniversityChengdu610031China Technology and Equipment of Rail Transit Operation and Maintenance Key Laboratory of Sichuan Province Southwest Jiaotong UniversityChengdu610031China State Key Laboratory of Tribology Tsinghua UniversityBeijing100084China Beijing Key Laboratory of Long-life Technology of Precise Rotation and Transmission Mechanisms Beijing Institute of Control EngineeringBeijing100094China

Achievement of steady and reliable super-low friction at the steel/steel contact interface,one of the most tribological systems applied for mechanical moving parts,is of importance for prolonging machine lifetime and reducing energy *** we reported that the superlubricity performance of the steel/steel sliding interface lubricated with tiny amounts of diketone solution strongly depends on the oxygen content in surrounding *** increase of oxygen not only significantly shortens the initial running-in time but also further reduces the stable coefficient of friction in superlubricity stage due to the enhancement of tribochemical *** the one hand,more severe oxidation wear occurring at higher oxygen content facilitates material removal of the contact interface,lowering the contact pressure and the corresponding initial *** the other hand,the growth of iron ions during the shear process in high oxygen environment promotes the formation of chelate which acted as an effective lubricated film chemisorbed at the steel/steel friction interface to further lower the interfacial *** results provide a new opportunity to further optimize the tribological performance of diketone superlubricity system,especially towards the lubrication of mechanical engineering materials.

关键词： superlubricity oxygen content steel/steel interface diketone chelate

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

以断层活化突水事故为例的煤矿灾害感知研究

有色设备 2024年第2期38卷 24-31页

作者：孙文斌张纪扬陈东伟山东科技大学能源与矿业工程学院山东青岛266590 山东鲁泰控股集团有限公司安全生产与应急管理部山东济宁272000

煤矿智能化的发展为提升矿井安全保障能力提供了新的思路,但在煤矿灾害的感知方法研究上仍有不足,难以对灾害发育的阶段进行有效感知,缺少针对灾害发育不同阶段的防治措施。针对上述问题,本文提出了一种基于灾害演化特征分析的煤矿灾害... 详细信息

煤矿智能化的发展为提升矿井安全保障能力提供了新的思路,但在煤矿灾害的感知方法研究上仍有不足,难以对灾害发育的阶段进行有效感知,缺少针对灾害发育不同阶段的防治措施。针对上述问题,本文提出了一种基于灾害演化特征分析的煤矿灾害感知方法,通过研究矿井灾害发育机制,划分灾害的演化阶段,提取阶段的转化条件并识别控制因素,结合关联性分析方法,选择敏感控制因素进行灾害发育的阶段感知。以煤矿断层活化突水事故为例,进行了灾害感知方法的试验验证,结果表明,敏感控制因素随工作面推进的变化能够反映断层活化突水事故演化程度,因此,基于演化特征分析的感知方法有望为煤矿灾害发育阶段感知提供参考。

关键词：灾害感知敏感特征断层突水数值模拟