Development of 2D hybrid equilibrium elements in large increment method

As a force-based finite element method (FEM), large increment method (LIM) has been developed in recent years. It has been shown that LIM provided prominent advantage of parallel computation with high efficiency and low time consumption for member structural system. To fully utilize its advantage in parallel computation, it is the time to extend LIM to 2D and 3D continua analysis. In this paper, a 2D finite element library with the capability of modeling arbitrary configurations is developed. Some illustrative numerical examples are solved by using the proposed library; the obtained results are compared with those obtained from both traditional displacement-based FEM and analytical solutions, which has clearly shown the advantages of LIM.     

Simulation study of foundations reinforced with horizontal-vertical inclusions using particle flow code

A two-dimensional discrete element code, particle flow code (PFC2D), is employed to investigate foundations reinforced with horizontal-vertical (H-V) inclusions. The initial states and loading processes of both unreinforced and H-V reinforced foundations are simulated by PFC 2D method. The interface between particles and reinforcements, and the reinforcement mechanism of the H-V reinforced foundations are studied through stress distribution graphs, displacement vector graphs and contact force graphs. The simulation results demonstrate that the vertical elements of the H-V reinforcement keep the particles from being displaced under the applied load. The H-V reinforcement can distribute the load uniformly over a wider area, thereby improving the bearing capacity of soil foundation.     

基于效能及可靠性的车辆资产全寿命周期成本评估模型及应用系统

车辆资产管理是道路运输企业管理的重点内容,本文提出一种基于效能及可靠性的LCC评估算法,并在该评估模型基础上建立计算机管理系统。系统对车辆可靠性,成本、效能进行识别、量化和平衡,为企业在车辆购置、运行维护、报废淘汰等过程提供效益最优的决策方案。     

纳米TiO_2材料对沥青抗紫外光老化的作用

把纳米TiO2作为紫外线吸收抗老化剂加入到沥青中,根据紫外线老化前后沥青针入度、软化点、延度的试验结果,分析纳米TiO2及其掺量对沥青抗紫外线老化能力的影响。结果表明:掺入纳米TiO2的沥青,其紫外线老化后的针入度、延度都有所增加,软化点明显减小;针入度指数的增加程度降低;针入度、延度、软化点损失率均明显降低;纳米TiO2的最佳掺量为1%。纳米TiO2作为紫外线吸收抗老化剂在一定程度上提高了沥青抗紫外线的能力。     

二次变形模量EV2试验的尺寸效应研究

提出了承载板直径分别为400,600 mm的二次变形模量EV2的试验方法,通过对京沪高速、京石客运专线铁路路基施工现场试验数据的分析,得出承载板直径分别为300,400,600 mm的二次变形模量EV2试验结果之间的相关关系,并分析了填料最大粒径对试验结果的影响。     

SLC-Her-2/neu-p53-Fc融合基因重组腺病毒真核表达载体对荷黑色素瘤小鼠的免疫治疗效果

目的扩增纯化携带融合基因SLC-Her-2/neu-p53-Fc(SLC-HP-Fc)的重组腺病毒AdEasyTM-SLC-HP-Fc真核表达载体,研究其对荷黑色素瘤小鼠的免疫治疗效果。方法将重组腺病毒真核表达载体AdEasyTM-SLC-HP-Fc在人胚肾293细胞中扩增、纯化;向小鼠皮下注射表达Her-2/neu-p53融合基因的B16F10-psig-Her-2/neu-p53细胞(B16-HP细胞)建立荷黑色素瘤小鼠模型;将小鼠随机分成对照组、肌肉注射组和皮下注射组,用重组腺病毒AdEasyTM-SLC-HP-Fc真核表达载体进行治疗,观察肿瘤生长情况,测定细胞毒性活性、血清p53抗体。结果纯化后重组腺病毒AdEasyTM-SLC-HP-Fc真核表达载体滴度8×108pfu/mL。目的基因SLC-HP在小鼠体内成功表达。重组腺病毒AdEasyTM-SLC-HP-Fc真核表达载体高剂量肌肉注射能有效抑制小鼠肿瘤的生长,瘤重与对照组比较差异有统计学意义(P=0.005),抑瘤率达到98.8%,细胞毒性T淋巴细胞(CTL)的特异性杀伤力有明显提高。结论重组腺病毒AdEasyTM-SLC-HP-Fc真核表达载体高剂量肌肉注射能延长出瘤时间,抑制肿瘤的生长。     

国Ⅳ柴油机SO_2排放特性试验研究

在发动机台架上进行了某国Ⅳ柴油机的ESC测试,并利用FTIR气体分析仪对其SO2排放进行测量。对比了有无DOC+POC两种情况下发动机的SO2排放特性,分析了发动机进气方式、供油提前角和EGR率等参数对SO2排放的影响。结果表明,SO2与燃油消耗量之间有较好的相关性,DOC+POC后处理可有效减少常规污染物(NOx除外)和SO2的排放,增加进气压力和推迟供油可降低SO2的排放量。     

一种新的非全向散射MIMOM2M宽带衰落信道模型

针对MIMO移动对移动（mobile—tomobile,M2M）宽带通信系统提出了新的衰落信道模型,该模型根据T形街道几何散射模型推导而来。模型充分考虑了非全向单次、二次散射以及到达角（AoA）和发射角（AoD）之间的关系,据此关系推导了信道参考模型和仿真模型,并分析了仿真模型的相关特性,给出了空一时一频互相关函数的闭合表达式。最后,仿真模型与实测的多普勒功率谱密度（PSD）的对比相似度证明了该模型的可用性。     

港珠澳大桥珠澳口岸人工岛工程二维潮流泥沙数学模型研究

基于TK-2D软件建立了三角形网格的伶仃洋海域大范围二维潮流泥沙数学模型和港珠澳大桥的珠澳口岸人工岛工程区附近小范围局部细化的二维潮流泥沙数学模型,并根据现场实测资料对模型进行了验证模拟,在模型验证基础上,对珠澳口岸人工岛工程实施后的潮流泥沙进行了模拟研究,从潮流泥沙角度对人工岛工程对周围海区的影响进行了分析论证.研究...     

Impacts of an emission based private car taxation policy - First year ex-post analysis

This paper assesses the impacts of a targeted policy designed to influence car purchasing trends towards lower CO₂ emitting vehicles. Vehicle registration tax and annual motor tax rates in Ireland changed in July 2008 from being based on engine size to emissions performance of cars. This paper provides a one year ex-post analysis of the first year of the tax change, tracking the change in purchasing trends arising from the measure related to specific CO₂ emissions, engine size and fuel, and the implications for car prices, CO₂ emissions abatement, and revenue gathered. While engine efficiency improvements had been offset by purchasing trends towards larger and generally less efficient cars in the past, with the average MJ/km remaining constant from 2000 to 2007, this analysis shows that in the first year of the new taxation system the average specific emissions of new cars fell by 13% to 145 g/km. This was brought about, not by a reduction in engine size, but rather through a significant shift to diesel cars. Despite an unexpected reduction in car sales due to a recession in 2008, the policy measure has had a larger than anticipated impact on CO₂ emissions, calculated to be 5.9 ktCO₂ in the first year of the measure. The strong price signal did however result in a 33% reduction in tax revenue from VRT, in financial terms amounting to a drop of €166 million compared to a baseline situation.