挖泥船疏浚输泥管的材料选择

考虑到疏浚设备的耐磨性能受限于耐磨材料的制约,通过分析国内某耙吸挖泥船在输泥管路中的新材料应用,介绍耐磨复合材料在挖泥船上的应用优势,展望其在疏浚行业中的发展前景。     

废轮胎胎面胶粉改性沥青性能研究

通过对沥青基本性能和动态剪切流变性能的测试,分析研究了一种50目废轮胎胎面胶粉改性沥青的工艺参数和性能指标。研究表明,这种胶粉具有较好的高低温性能和高温存储稳定性,常规性能指标高于一些项目标准,路用性能等级能达到PG76。随着胶粉掺量的增加,沥青的软化点、延度、老化延度、弹性恢复、粘度、DSR值都呈上升变化趋势,此种胶粉掺量16%左右为宜;添加少量SBS的胶粉/SBS复合改性沥青较胶粉改性沥青具有更好的低温性能和高温抗车辙性能,老化后5℃的延度有明显的提高,路用性能等级能达到PG82。     

Influential factors in port infrastructure tariff formulation,implementation and revision

The process of formulation, revision and approval of port infrastructure tariffs is complex and involves different stakeholders. The extant literature focuses more on port pricing research but pays less attention to the practice of port infrastructure tariff setting. This paper aims to identify and analyses the influential factors in the port infrastructure tariff formulation process using survey data collected from 67 port authorities. Exploratory factor analysis (EFA) is first conducted before confirmatory factor analysis (CFA) is applied to analyse the latent factors underlying port infrastructure tariff setting. The analysis results suggested the four factors influential to infrastructure tariff practice, namely tariff policies, transparency, tariff regulation and stakeholder participation. The paper also presents the implications for port authorities, management and stakeholders.     

基于图研CR5000软件的线束设计

使用图研软件CR5000设计系统，搭配达梭CATLA V5软件的线束模块E12设计线束走势，产出现今使用的线束工程图面（HARNESS）与组装图，将线束设计方式软件化，降低开发线束产生的风险。     

趋化因子受体CX3CR1在大鼠重症急性胰腺炎中的表达和意义

目的探讨趋化因子受体CX3CR1在重症急性胰腺炎(severe acute pancreatitis,SAP)大鼠模型中的表达,判断其能否作为SAP发生的预测指标。方法 40只Sprague-Dawley大鼠随机分为假手术组(sham operation,SO)(n=20)和SAP模型组(n=20),分别于制模后6、12、24、48h处死大鼠,应用酶联免疫吸附试验(enzyme-linked immunosorbent assay,ELISA)法检测SAP大鼠血清中CX3CR1的变化,同时应用免疫组织化学法检测SAP大鼠胰腺、肺脏及肾脏组织中CX3CR1蛋白的表达。结果大鼠SAP制模成功后,血清中CX3CR1的表达逐渐升高,24h达最高(542.4pg/mL),明显高于SO组(P<0.05)。大鼠SAP组的胰腺、肺脏和肾脏组织中均有CX3CR1的表达,且明显高于SO组,其中胰腺和肺脏组织中CX3CR1表达在制模24h达高峰,肾脏组织中CX3CR1表达在制模48h达高峰。结论趋化因子受体CX3CR1可能为预测SAP严重程度的有效指标之一,值得进一步深入研究。     

The variational formulation of a non-equilibrium traffic flow model: Theory and implications

The analysis and numerical solution of non-equilibrium traffic flow models in current literature are almost exclusively carried out in the hyperbolic conservation law framework, which requires a good understanding of the delicate and non-trivial Riemann problems for conservation laws. In this paper, we present a novel formulation of certain non-equilibrium traffic flow models based on their isomorphic relation with optimal control problems. This formulation extends the minimum principle observed by the LWR model. We demonstrate that with the new formulation, generic initial-boundary conditions can be conveniently handled and a simplified numerical solution scheme for non-equilibrium models can be devised. Besides deriving the variational formulation, we provide a comprehensive discussion on its mathematical properties and physical implications.     

一种盾尾密封油脂的配方研究与性能表征

采用正交试验法获得了WY盾尾密封油脂的优化配方,其配方组成为性能优异的基础油、复合黏度指数改进剂、天然可降解纤维和颗粒填充剂等。采用自制抗水压密封装置和熔融流动速率仪表征其抗水压密封性和泵送性,并将其与国内外同类产品进行比较。结果表明,该产品的抗水压密封性能与CONDAT产品一致,在3.5 MPa下,不漏水;泵送性是国内某品牌油脂的2~3倍,使该性能指标进一步接近国际水平。     

基于常规试验数据的沥青劲度模量一般公式表达

在范得普诺模图的基础上,以针人度指数PI和实际温度与软化点(环球法)的差△Y为变量,通过回归分析,推演了基于常规试验数据的沥青劲度模量一般公式表达。比较显示,查图与公式预测的沥青劲度模量达到了相当高的一致性,在保证率为90％时,误差对应的温度差不超过2℃。公式表达完成了从诺模图模拟性到数学确定性的转换,方便了使用,保证了精度,并为常规试验表示的沥青劲度融人现代计算技术提供了条件。此外,本文的成果,也为研究开发利用常规试验数据理性地描述沥青性质的方法准备了前提。     

GEOMETRICALLY NONLINEAR FE FORMULATIONS FOR THE MACRO-ELEMENT UNIPLET OF FOLDABLE STRUCTURES

Introduction　　 Pantographic foldable structure works on theprinciple of a pantograph[1,2 ] . A structure of thistype may be referred to as“pantograph structure”,or simply“p- structure”. The basic unit for the p-structure is a componentso- called duplet[3 ] ,orpan-tograph unit[4] ,Scissor- Like Element ( SLE) [5] ,asshown in Fig.1 .A pantograph unitconsists of twocoplanar straightbars called uniplet,which are ca-pable of rotating about the intermediate pivot,re-ferred to as a scissor h…     

浅谈公路工程投标报价策略及技巧

投标标价编制与最终报价是投标的关键性工作,也是整个投标工作的核心,企业应给予高度重视。报价策略运用是否得当,不仅关系到施工企业能否中标,还关系到企业在激烈的竞争中能否生存和发展。我们只有不断总结投标价的经验和教训,才能不断提高我们的报价水平,在激烈的竞标中立于不败之地。