乘用车制动盘黑色印记问题研究

车辆在行驶一段里程之后,会在车辆制动盘表面形成一圈可变的黑色印记。随着里程的变化,黑色印记位置和宽度会发生随机变化。该黑色印记用手触摸无明显触感,仅仅是不美观,但会给用户造成不安感,认为制动系统存在问题。针对该现象,进行了大量的台架和整车试验分析,结果表明制动盘的机加工工艺和制动衬块的材料是引起问题的主要原因。通过更改制动盘机加工工艺及制动衬块材料,可以解决制动盘黑色印记问题。     

关于水泥混凝土路面“白改黑”的探讨——以南浔人瑞东路改建工程为例

由于沥青路面行驶平稳、无接缝,国内很多水泥混凝土路面都将改造为沥青路面（简称“白改黑”）。以浙江南浔人瑞东路为实例,探讨此类工程的设计及施工经验,能起到抛砖引玉的作用。     

“三化”工作实施方法探讨

文章介绍了“三化”(通用化、系列化、模块化)工作的推进思路和具体实施方法,以及“三化”项目成果奖励、应用、管理和推广实现。尤其是在“三化”产品改进、成果管理方面,提出了具体的实施办法,促进了企业“三化”产品和“三化”项目管理的同步提高。     

Natural variability in exposure to fine particles and their trace elements during typical workdays in an urban area

Studies on the natural human exposures to fine particulate matter (PM_2.5) and their elements composition are practically non-existent in South America. In order to understand the natural exposure of the typical Brazilian population to PM_2.5 and their trace element composition, we measured PM_2.5 concentrations and collected mass on filters for nine continuous hours during a typical workday of volunteers. In addition, bus routes were performed at peak and non-peak periods, mimicking the routine activity of the population. Mean concentrations of PM_2.5 in the bus and car groups were similar while the fraction of BCe was higher for the bus group. For all routes, mean PM_2.5 concentrations were higher during peak than non-peak hours, with an average of 43.5 ± 33.1 μg m⁻³ and 14.3 ± 10.2 μg m⁻³, respectively. The trace elements S, K and Na originated mainly from vehicle emissions; Na was associated with the presence of biofuel in diesel. Toxic elements (Pb, Cr, Cu, Ni, Zn, Mn) were found at low levels as evident by the total hazard index that ranged from 2.15 × 10⁻⁰³ to 1.38 for volunteers. For all routes, the hazard index ranged from 2.25 × 10⁻⁰³ to 5.03. Average PM_2.5 respiratory deposition dose was estimated to be 0.60 μg/kg-hour for peak hours. Potential health damages to people during their movements and at workplaces close to the traffic were identified. Improvements in the design of the building to reduce the entrance of air pollutants as well as the use of filters in the buses could help to limit population exposure.     

Variability of mesozooplankton spatial distribution in the North Aegean Sea, as influenced by the Black Sea waters outflow

The North Aegean Sea constitutes an important region of the Mediterranean Sea since in its eastern part the mesotrophic, low salinity and relatively cold water from the Black Sea (outflowing from the Dardanelles strait) meets the oligotrophic, warm and very saline water of Levantine origin, thus forming a thermohaline front. Mesozooplankton samples were collected at discrete layers according to the hydrology of the upper 100 m, during May 1997 and September 1998. In May highest biomass and abundance values (up to 66.82 mg m^− 3 and 14,157 ind m^− 3) were detected in the 10–20 m layer (within the halocline) of the stations positioned close to the Dardanelles strait. The front moved slightly southwards in September, characterized by high biomass and abundance values within the halocline layer. The areas moderately or non influenced by Black Sea water revealed lower standing stock values than the frontal area in both cruises and maxima were detected in the uppermost low salinity layer. Samples collected at the stations and/or layers more influenced by Black Sea water were distinguished from those collected at layers and/or stations more affected by Levantine waters in both periods. In May the former samples were characterized by the copepods Acartia clausi, Centropages typicus, Paracalanus parvus. The abundance of the above species decreased gradually with increasing salinity, in the horizontal and/or in the vertical dimension, with a parallel increase of the copepods Oithona plumifera, Oithona copepodites, Oncaea media, Ctenocalanus vanus, Farranula rostrata. During September the frontal area as well as that covered by the modified Black Sea water, were highly dominated by the cladoceran Penilia avirostris and doliolids. For both seasons, MDS plots, issued from the combination of mesozooplankton and water-type data, revealed the gradual differentiation of zooplankton composition from the frontal area towards the area covered by Levantine water, following the spreading and mixing of the Black sea water. The observed temporal and spatial variability in the distribution pattern of mesozooplankton standing stock and species composition seems to depend considerably on the variability of circulation and frontal flows.     

深中通道超宽钢壳混凝土沉管管节浇筑变形控制

深中通道沉管隧道是目前世界上单节管节最宽同时也是单个行车道孔最宽的公路沉管隧道,建设标准为双向八车道高速公路,部分超宽段甚至超过双向十车道,标准管节宽度为46 m,最宽管节的最大宽度达55.467 m。管节结构采用了在内外双层钢壳内填充高流动自密实混凝土的“三明治”复合结构形式,为此结构形式在中国的首次大规模应用。其管节预制精度要求高,在混凝土浇筑阶段的变形控制要求达毫米级。在混凝土浇筑过程中,为将管节内净空变形控制在10 mm以内,原设计要求在顶板浇筑过程中在管内行车道孔增设临时支撑杆措施。为此,应用精细三维有限元模拟管节的浇筑过程,考虑其三维力学效应及混凝土逐渐凝固后的承载能力,并结合混凝土浇筑布料设备的特点,寻求出满足变形验收条件和兼顾施工效率的最优浇筑顺序,并以此取消管内临时支撑杆措施的制约。最后,该浇筑顺序在首节管节E32(同时也是最宽管节)的浇筑预制中成功应用,实测结果与计算结果吻合,满足验收要求。该技术精准控制了管节浇筑阶段的变形,优化了管节预制和舾装的施工方案,取消了顶板浇筑过程的管内临时支撑杆措施,使每节管节内的一次舾装作业得以提前约1个月启动,并可与墙体和顶板浇筑作...     

校企互聘共用助力“三教”改革——以福建船政交通职业学院万商现代学徒制订单班为例

文章以福建船政交通职业学院汽车电子技术专业现代学徒制万商班为例,阐述了开展现代学徒制的的必要性、分析了高职院校“三教”方面存在的问题,阐述了基于现代学校制的三教改革。     

鉴别道路交通事故多发点的模糊评价法

道路交通事故多发点的鉴别是改善道路交通安全状况最关键、最重要的一步,当被鉴别路段或交叉口的道路条件、交通条件相差较大时,采用原有的鉴别方法就难以保证鉴别精度,而又鉴于交通安全概念的模糊性、评价者思维方式的多样性以及评价结果常以口语化词汇表达的特点,提出了鉴别道路交通事故多发点的模糊评价方法。经过分析比较,模糊评价方法采用的指标是亿车公里死亡率、万车死亡率、万车当量总事故次数及事故严重性指数。在此基础上,建立了二层模糊数学评价模型,以哈尔滨市区内部分道路路段及交叉口的交通事故多发点作为应用示例进行了道路交通事故多发点鉴别。     

基于“门到门”运输的铁路物流“库存-运输”模型研究

我国铁路货运改革提出了"门到门"运输的发展模式,给铁路物流企业提出了新的要求和挑战。对于铁路货运来讲,这是改变体制、面向竞争、融入市场的良好发展契机。铁路物流企业将来要更多的承担全程物流的任务,因此,如何在具有"效益悖反"的库存和运输之间获得整体最优的运输模式成为亟待解决的问题。本文分析了铁路物流系统中的库存和运输费用,用时间因素反映二者的效益悖反关系,建立了以铁路运输为主导、联合多种运输方式实现"门到门"运输的库存-运输整体最优模型,提出求解模型的模拟退火算法,并对一算例进行简单分析,最后基于模型为铁路物流企业的发展提供针对性建议。     

黑盒测试技术在嵌入式软件测试中的融合应用

近些年来,嵌入式软件的规模及复杂程度急剧增大,尤其在国防、轨道交通、汽车、民航以及工业控制等领域的用户对嵌入式软件质量要求更加严格,使用过程中对嵌入式软件缺陷的容忍度越来越低。因此,如何有效提高嵌入式软件的质量成为目前迫切需要解决的问题。文章以某款新能源汽车整车控制策略中的空调控制模块为例,分析了如何将等价类划分法、边界值分析法、因果图分析法等黑盒测试技术有序高效地融合应用在嵌入式软件测试用例设计之中;文章阐明了使用不同类型的黑盒测试用例设计方法相互融合的嵌入式软件测试思路,可以有效、有序地设计出一组可靠性高、执行性强的功能测试用例,从而提高了测试的效率,保证了软件测试的置信度和软件质量。