摩托车私换发动机被罚后方悔懂法迟

在有些摩托车驾驶员的头脑中,有一种模糊观念:更换发动机要申请批准,那是对汽车而言.摩托车么,路面执勤警察查验发动机的情况很少,何况摩托车又没有报废期限,私下换个发动机,就可延长车子使用期.但这些人忽略了交通法规的有关规定,摩托车如要更换发动机,同样要办理变更手续,经批准方可更换.不然的话,也将受到处罚.江苏省海安县的一名"骑手"就因不懂此法规,擅自更换摩托车发动机,并尝到了苦头.     

Composition-dependent mechanical and thermal transport properties of carbon/silicon core/shell nanowires

Molecular dynamics (MD) simulations are performed to study the composition-dependent elastic modulus and thermal conductivity for carbon/silicon core/shell nanowires (NWs). For each concerned carbon/silicon core/shell NW with a specified diameter, it is found that elastic modulus is reduced with a linear dependence on cross-sectional area ratio. The fact matches well with the results of theoretical model. Analysis based on the cross-sectional stress distribution indicates that the core region of core/shell NW is capable of functioning as a mechanical support. On the other hand, thermal conductivity also relies on the cross-sectional area ratio of amorphous silicon shell. The core/shell interface plays a considerable influence on the thermal transport property. The decreasing rate of thermal conductivity is gradually decreased as the composition of amorphous silicon shell increases. In addition, by calculating the phonon density of state, we demonstrate that the reduction in thermal conductivity of the core/shell NW stems from the increase of the low frequency modes and the depression of high-frequency nonpropagating diffusion modes. These results provide an effective way to modify the properties of core/shell NWs for related application.     

浅谈实验室质量管理体系建设

当前,全国已有5000多家实验室依据《实验室资质认定评审准则》《检测和校准实验室能力认可准则》建立了质量管理体系,通过了国家实验室认可。这些实验室通过对质量管理体系的持续改进,使基础设施、检测手段、人员素质及管理水平得到了极大的提高,增强了实验室的市场竞争能力,赢得政府部门、社会各界的信任,从而大大提高了经济和社会效益。本文主要从三个方面谈谈实验室如何做好质量管理体系建设。     

某型船用空压机虚拟拆装系统研究与开发

虚拟现实技术已经广泛应用与各个领域。将虚拟现实技术应用到操作训练中,不仅可以降低训练成本,而且不用受制于场地的限制。本文设计并实现了基于VC和EON的船用空压机虚拟拆装训练系统,通过EonX控件实现EON和VC之间的通信,并且将学生的训练信息记录在数据库中,可以根据记录的信息进行有针对性的训练,起到较好的训练效果。