检索结果-南通市图书馆

Construction of core@double-shell structured energetic composites with simultaneously enhanced thermal stability and safety performance

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） 2024年第4期34卷 134-142页

作者： Peng Wang Wen Qian Ruolei Zhong Fangfang He Xin Li Jie Chen Li Meng Yinshuang Sun Guansong He Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China State Key Laboratory of Environment-friendly Energy Materials School of Materials and ChemistrySouthwest University of Science and TechnologyMianyang 621010China

The poor thermal stability and high sensitivity severely hinder the practical application of hexanitrohexaazaisowurtzitane(CL-20).Herein,a kind of novel core@double-shell CL-20 based energetic composites were fabricated to address the above *** coordination complexes which consist of natural polyphenol tannic acid(TA) and Fe~Ⅲ were chosen to construct the inner shell,while the graphene sheets were used to build the outer *** resulting CL-20/TA-Fe~Ⅲ/graphene composites exhibited simultaneously improved thermal stability and safety performance with only 1 wt% double-shell content,which should be ascribed to the intense physical encapsulation effect from inner shell combined with the desensitization effect of carbon nano-materials from outer *** phase transition(ε to γ) temperature increased from 173.70 ℃ of pure CL-20 to 191.87℃ of CL-20/TA-Fe~Ⅲ/graphene ***,the characteristic drop height(H_(50)) dramatically increased from 14.7 cm of pure CL-20 to112.8 cm of CL-20/TA-Fe~Ⅲ/graphene composites,indicating much superior safety performance after the construction of the double-shell *** general,this work has provided an effective and versatile strategy to conquer the thermal stability and safety issues of CL-20 and contributes to the future application of high energy density energetic materials.

关键词： CL-20 Double-shell structure Thermal stability safety performance Tannic acid Graphene sheets

Highway Concrete Guardrail Lifting Scheme and safety performance Verification

在线全文

学校读者我要写书评

暂无评论

Journal of Transportation Technologies 2021年第1期11卷 1-13页

作者： Ronggui Zhou Yidan Xie Jiangang Qiao Road Traffic safety Technology Transportation Industry Key Laboratory Beijing China School of Civil Engineering and Transportation Hebei University of Technology Tianjin China

In order to achieve the old fence of reuse, improve the safety performance of guardrail, barrier structure does not meet the requirements, make full use of the old concrete guardrail on the basis of heightening, through computer simulation experiment were analyzed, and optimization design, through the real car collision test, make the concrete guardrail after heightening structure satisfies the requirement of the safety performance of current specification. The results show that the protective performance of the two guardrail schemes meets the requirements of the current guardrail evaluation standards through the computer simulation experiment. Through the optimized design of scheme 1, the actual car crash test proves that the enhanced structure of Minhua TYPE II concrete guardrail can meet the requirements of safety performance evaluation. The research results provide an important basis for the transformation of the guardrail and the revision of the current design of expressway in China.

关键词： Concrete Guardrail Scheme Optimization Simulation Real Vehicle Collision safety performance

Spacecraft rendezvous trajectory safety quantitative performance index eliminating probability dilution

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2014年第6期57卷 1219-1228页

作者： SUN ZhenJiang LUO YaZhong NIU ZhiYong College of Aerospace Science and Engineering National University of Defense Technology

In view of the probability dilution problem of the existing quantitative indexes of rendezvous trajectory safety performance using collision probability,this paper proposes a new quantitative index of rendezvous trajectory safety performance by well combining collision probability with warning *** proposed new index increases monotonously as the position errors of the chaser spacecraft increase,therefore it can effectively overcome the problems of the reduction in the largest performance value and the advancement in the most dangerous time induced by the probability *** proposed new index is applied to the safety design of close range rendezvous *** mission’s safety requirements for initial navigation precision and the safe region of initial and final keeping points’positions with a certain navigation precision are analyzed,and several valuable conclusions about the relation between position navigation precision and velocity navigation precision as well as the relation between keeping points’positions and navigation precision are obtained.

关键词： rendezvous and docking safety performance probability dilution missing alarm probability

Communication’s Role in safety Management and performance for the Road safety Practices

在线全文

学校读者我要写书评

暂无评论

International Journal of Transportation Science and Technology 2014年第1期3卷 79-93页

作者： Salim Keffane(s) Department of Psychology University Setif 2SetifAlgeria

Communication among organizations could play an important role in increasing road *** get in-depth knowledge of its role,this study measured managers’and employees’perceptions of the communication’s role on six safety management and performance criteria for road safety practices by conducting a survey using a questionnaire among 165 employees and 135 *** analysis using AMOS-19 software shows that some of the safety management road safety practices have high correlation with the safety performance,namely,from the six antecedents,only the safety training and safety promotion,closely correlate with the safety motivation,and only safety commitment,safety communication and feedback have close relations with the safety knowledge and safety behavior compliance,and only safety feedback has effective relations with the safety *** feedback is identified as the most important safety management issue to road safety practices and it would predict the level of safety knowledge,safety motivation,safety compliance and safety *** results of this study would help the concerned agencies/orgaizations in improving their ability to assess the road safety indicators and to the future development of the safety performance management for road safety practices in these agencies.

关键词： safety communication safety performance safety management safety behavior Road safety practices

Developing crash modification factors for roundabouts using a cross-sectional 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

Journal of Traffic and Transportation Engineering(English Edition) 2020年第3期7卷 362-374页

作者： Mohammad Nour Al-Marafi Kathirgamalingam Somasundaraswaran Ron Ayers School of Civil Engineering and Surveying Faculty of HealthEngineering and SciencesUniversity of Southern QueenslandT oow oom baQLD 4350Australia

The objective of the current study was to evaluate traffic and geometric features and their influences on the safety performance of roundabouts by developing suitable crash modification factors(CMFs).The cross-sectional method can be applied as an alternative method to estimate the CMFs when before-and-after studies are impractical to apply,e.g.,lack of data from the period after implementing *** accomplish the study objective,CMFs were derived from generalised linear models(GLMs),i.e.,negative binomial(NB)regression,using data collected on regional roundabouts in Toowoomba City,*** years of crash data from 49 roundabouts included all recorded crashes as well as traffic and geometric features for the entire *** candidate models were developed using the *** models were selected based on statistical significance,goodness-of-fit(GOF)measures,and cumulative residual(CURE)*** results show that increasing the number of entry lanes,entry width,entry radius,traffic volume,circulatory roadway width,weaving width,and speed limit have positive effects on roundabout *** the other hand,increasing the number of legs,number of exit lanes,exit width,exit radius,weaving length,central island diameters,and presence of fixed object on a central island have negative effects on roundabout *** study shows that quantifying the risk factors can support road safety stakeholders to identify safety improvements at roundabouts more effectively and efficiently.

关键词： safety performance Generalised linear models Crash modification factors Cross-sectional method Roundabouts

Effects of calibration process on the simulation of rear-end conflicts at roundabouts

在线全文

学校读者我要写书评

暂无评论

Journal of Traffic and Transportation Engineering(English Edition) 2019年第2期6卷 175-184页

作者： Vincenzo Gallelli Giuseppe Guido Alessandro Vitale Rosolino Vaiana Department of Civil Engineering University of Calabria

A methodology for calibrating and validating VISSIM simulation model is presented that allows to replicate the observed vehicles conflicts. A roundabout case study has been selected to test the usefulness of a combined approach of VISSIM simulation package and the surrogate safety assessment model(SSAM) for providing reliable estimates of traffic conflicts. safety performance has been assessed from the field by video-recording vehicle interactions at the roundabout, and then expressed in terms of time to collision(TTC)*** proposed calibration procedure has been performed by a multistage methodology involving microscopic drivers' car following behavior parameters to enhance the correlation between observed and simulated queue lengths at the roundabout's entries. The calibration procedure is based on a statistical screening of inputs leading to a linear expression relating significant parameters to the queue length. The best estimates of the model's parameters have been determined using a genetic algorithm *** spatial distribution of the rear-end conflicts and the TTC values determined by SSAM have been finally compared with the observed ones to analyze the capability of the model of replicating rear-end *** results suggest to this calibration procedure impacts positively on the estimate of the safety performance measures obtained through the simulation *** the good results in the evaluation of the model's accuracy, the simulation seems to fail in reproducing the traffic phenomena linked to unusual driving behavior, and therefore it is not able to replicate forced drivers' maneuvers that can lead to a conflict situation.

关键词： Simulation safety performance Unmanned aerial vehicle Roundabouts Traffic conflicts

performance of the Transmission Parking Mechanism of a Battery Electric Vehicle Simulated with Adams Software

在线全文

学校读者我要写书评

暂无评论

Automotive Innovation 2018年第2期1卷 114-121页

作者： Yuan Dong Yong Chen Chuang Yu Zhan Cao Guangxin Li Zhuoqiang Li Genqun Cui School of Mechanical Engineering Hebei University of TechnologyTianjin 300130China Powertrain Research Institute GeelyHangzhou Bay 315336China

The electric parking mechanism is studied for an electrically controlled two-speed auto transmission that is being developed for electric *** requirements include low-speed safe parking,reliable self-lock and the avoidance of abnormal parking.A dynamic model of the parking mechanism is established and analyzed using Adams ***,failure of the parking mechanism due to wear is observed in bench testing and compared with experimental results after optimization.

关键词： Battery electric vehicle Two-speed auto transmission Parking mechanism safety performance

Safe rendezvous scenario design for geostationary satellites with collocation constraints

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Astrodynamics 2017年第1期1卷 71-83页

作者： Ya-Zhong Luo Zhen-Jiang Sun College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China

Rendezvous on the geostationary orbit(GEO)is much more complex than that on the low earth orbit and has a higher critical requirement for safety *** paper presents a safe scenario design method for GEO rendezvous proximity missions where the safety constraint of a collocated satellite is considered.A recently proposed quantitative index considering trajectory uncertainty is introduced to analyze the safety performance of the scenario parameters including the V-bar keeping positions and the fly-by trajectory ***,an exhaustive analysis is performed to find the dangerous regions of the V-bar keeping positions and the appropriate semi-major axis of the fly-by ellipse,considering the safety requirements of both the target and the collocated satellite.A geometry method is then developed for designing a feasible and suboptimal safe rendezvous *** method is tested by designing four rendezvous scenarios with±V-bar approach directions respectively in the situations with and without one collocated *** performance and velocity increments of the scenarios are compared and a conclusion is reached that the collocated satellite has a significant influence on the scenario design.

关键词： geostationary orbit(GEO) rendezvous and docking(RVD) safety performance satellite collocation

Analysis on safety Influencing Factors on Highway Interchange Design

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 Architectural Research and Development 2022年第3期6卷 27-32页

作者： Yaoping Luo Yun Wan China Railway Changjiang Transport Design Group Co. Ltd.Chongqing 401147China Zhongdu Engineering Design Co. Ltd.Southwest BranchChongqing 400064China

This paper briefly introduces the safety performance of the highway interchange *** factors that influence the safety of the highway interchange design,was discussed in the paper based on the parts,which are the safet... 详细信息

关键词： Highway Design of interchange Security safety performance