大连石灰石矿矿坑边坡绿化植物种类选择

大连石灰石矿矿坑边坡绿化生态修复工程主要采用厚层基材喷附和液力喷播两种工艺,喷播植物种类的选择将直接影响其生态修复效果。以该工程为例,根据工程区地理及环境特征,基于边坡绿化的基本原则,因地制宜地提出了适宜的边坡绿化植物。     

广州市轨道交通四号线联络通道设计及施工工艺

针对广州市轨道交通四号线某段联络通道,从设计方案、施工工艺和技术要点等方面进行了详细介绍,重点介绍了基于地层特性采取的设计方案及其施工工艺流程,包括竖井结构、开挖步骤、支护加固等,实践证明该设计方案及施工工艺是合理、有效的,确保了该联络通道的顺利完工,可为类似工程提供参考。     

Differences in Long-term Medical Consequences Depending on Impact Direction Involving Passenger Cars

Objective: There is limited knowledge of the long-term medical consequences for occupants injured in car crashes in various impact directions. Thus, the objective was to evaluate whether injuries leading to permanent medical impairment differ depending on impact direction.

Methods: In total, 36,743 injured occupants in car crashes that occurred between 1995 and 2011 were included. All initial injuries (n = 61,440) were classified according to the Abbreviated Injury Scale (AIS) 2005. Injured car occupants were followed for at least 3 years to assess permanent medical impairment. The data were divided into different groups according to impact direction and levels of permanent impairment. The risk of permanent medical impairment was established for different body regions and injury severity levels, according to AIS.

Results: It was found that almost 12% of all car occupants sustained a permanent medical impairment. Given an injury, car occupants involved in rollover crashes had the highest overall risk to sustain a permanent medical impairment. Half of the head injuries leading to long-term consequences occurred in frontal impacts. Far-side occupants had almost the same risk as near-side occupants. Occupants who sustained a permanent medical impairment from cervical spine injuries had similar risk in all impact directions (13%) except from rollover (17%). However, these injuries occurred more often in rear crashes. Most of the injuries leading to long-term consequences were classified as minor injuries by AIS for all impact directions.

Conclusions: Studying crash data from a perspective of medical impairment is important to identify injuries that might not be prioritized only considering the AIS but might lead to lower quality of life for the occupant and also costs for society. These results can be used for road transport system strategies and for making priority decisions in vehicle design.     

The Influence of Enhanced Side Impact Protection on Kinematics and Injury Measures of Far- or Center-Seated Children in Forward-Facing Child Restraints

Objective: To evaluate the influence of forward-facing child restraint systems’ (FFCRSs) side impact structure, such as side wings, on the head kinematics and response of a restrained, far- or center-seated 3-year-old anthropomorphic test device (ATD) in oblique sled tests.

Methods: Sled tests were conducted utilizing an FFCRS with large side wings and with the side wings removed. The CRS were attached via LATCH on 2 different vehicle seat fixtures—a small SUV rear bench seat and minivan rear bucket seat—secured to the sled carriage at 20° from lateral. Four tests were conducted on each vehicle seat fixture, 2 for each FFCRS configuration. A Q3s dummy was positioned in FFCRS according to the CRS owner's manual and FMVSS 213 procedures. The tests were conducted using the proposed FMVSS 213 side impact pulse. Three-dimensional motion cameras collected head excursion data. Relevant data collected during testing included the ATD head excursions, head accelerations, LATCH belt loads, and neck loads.

Results: Results indicate that side wings have little influence on head excursions and ATD response. The median lateral head excursion was 435 mm with side wings and 443 mm without side wings. The primary differences in head response were observed between the 2 vehicle seat fixtures due to the vehicle seat head restraint design. The bench seat integrated head restraint forced a tether routing path over the head restraint. Due to the lateral crash forces, the tether moved laterally off the head restraint reducing tension and increasing head excursion (477 mm median). In contrast, when the tether was routed through the bucket seat's adjustable head restraint, it maintained a tight attachment and helped control head excursion (393 mm median).

Conclusion: This testing illustrated relevant side impact crash circumstances where side wings do not provide the desired head containment for a 3-year-old ATD seated far-side or center in FFCRS. The head appears to roll out of the FFCRS even in the presence of side wings, which may expose the occupant to potential head impact injuries. We postulate that in a center or far-side seating configuration, the absence of door structure immediately adjacent to the CRS facilitates the rotation and tipping of the FFCRS toward the impact side and the roll-out of the head around the side wing structure. Results suggest that other prevention measures, in the form of alternative side impact structure design, FFCRS vehicle attachment, or shared protection between the FFCRS and the vehicle, may be necessary to protect children in oblique side impact crashes.     

区域轨道交通系统节点重要度及故障恢复研究

为提高区域轨道交通系统(RRTS)正常运营下的可靠性和故障情况下的弹性,分析区域轨道交通网络(RRTN)的拓扑特性,构建拓扑结构弹性评价模型,实现突发条件下系统弹性的定量评价;提出一种基于系统弹性的结构评价方法,根据节点重要度评价,识别出系统关键节点;应用弹性损失三角形,进行多种故障情况下系统最优恢复策略研究。结果表明:RRTN在Space L模型下具有无标度网络特性;系统弹性分析结合科普兰评分法,可以提高RRTS节点重要度评价的准确性;最优故障恢复策略从全局角度寻求不同恢复策略下系统弹性的最大值,优化了RRTS结构弹性和系统恢复能力。     

Degradation mechanism of 2,4,6-trinitrotoluene in supercritical water oxidation

The 2,4,6-trinitrotoluene(TNT)is a potential carcinogens and TNT contaminated wastewater,which could not be effectively disposed with conventional treatments.The supercritical water oxidation(SCWO)to treat TNT contaminated wastewater was studied in this article.The TNT concentration in wastewater was measured by high-performance liquid chromatograph(HPLC)and the degraded intermediates were analyzed using GC-MS.The results showed that SCWO could degrade TNT efficiently in the presence of oxygen.The reaction temperature,pressure,residence time and oxygen excess were the main contributing factors in the process.The decomposition of TNT was accelerated as the temperature or residence time increased.At 550℃,24 MPa,120 s and oxygen excess 300%,TNT removal rate could exceed 99.9%.Partial oxidation occured in SCWO without oxygen.It was concluded that supercritical water was a good solvent and had excellent oxidation capability in the existence of oxygen.The main intermediates of TNT during SCWO included toluene,1,3,5-trinitrobenzene,nitrophenol,naphthalene,fluorenone,dibutyl phthalate,alkanes and several dimers based on the intermediate analysis.Some side reactions,such as coupled reaction,hydrolysis reaction and isomerization reaction may take place simultaneously when TNT was oxidized by SCWO.     

高速铁路列车运行冲突管理总论

为提高铁路行车指挥水平、保障行车安全,研究了高速铁路列车运行冲突管理问题。以高速铁路运输系统特点分析为基础,在定义高速铁路列车运行冲突后,对列车运行冲突从4个不同角度进行分类。分析列车运行冲突的特点,阐述高速铁路列车运行冲突管理的内涵。列车运行冲突的形成机理研究、冲突分析、冲突消解和基于冲突管理的列车运行调整方法和运行图研究等问题构成中国高速铁路冲突管理的主要研究框架体系。高速铁路冲突管理理论体系的研究是高速铁路运输组织优化的关键问题之一,是高速铁路行车安全的重要保障。     

汽车整车结构侧面耐撞性有限元数值模拟

目的研究汽车结构侧面主要承载部件的耐撞性,参考我国碰撞法规和ECE R95,根据国内某SUV汽车的参数和相关标准建立整车有限元模型和移动可变形壁障模型(MDB),对其进行数值模拟,为结构的优化设计提供参考。方法利用Hyper Mesh前处理将CAD模型转化为CAE有限元模型,输出k文件,并通过LS-DYNA大变形有限元仿真软件对其耐撞性进行计算。结果仿真结果显示,在汽车侧面碰撞过程中,B柱和车门等主要承载部件发生了较大的变形,B柱变形量为116.6 mm,车门的变形量为190 mm,其值符合标准要求,在碰撞结束后保证了足够的乘员空间。结论该车有较好的侧面耐撞性,且得出的碰撞数值模拟结果可为该车的结构设计提供参考。     

高速公路边坡生态防护系统探讨

分析了高速公路边坡特点及其侵蚀机理,阐述了过去我国边坡防护方式的不足之处,提出了边坡防护类型选择原则及生物防护方式的优势所在,同时还指出当前边坡防护中存在的问题.     

轨道交通电连接器国内环境试验标准分析

铁路作为国民经济大动脉、国家重要基础设施和大众化交通工具,在国民经济和社会生活中的作用至关重要。电连接器是铁路车辆设备的关键器件之一,有着很高的安全性和可靠性要求。着重分析了轨道交通电连接器标准中的电性能、机械性能和环境适应性的试验方法,并对这些标准进行了对比总结。经分析发现,更新版本的标准比被替换的标准增加了试验项目,细化了试验条件。然而,目前国内轨道交通电连接器的标准版本相对落后,仅GB/T 25022和GB/T 25023为2010年发布实施。亟需新的标准或试验方法以指导轨道交通电连接器的质量检测和认证。