渗流作用下新型装配重力式挡土墙有限元分析

为研究渗流作用下新型装配重力式挡土墙应力变化及墙体排水通道对墙后土体固结的影响,采用ABAQUS进行有限元分析,有限元分析结果与模型试验结果相吻合,证明该模型的合理性。在此基础上研究渗流作用下墙体应力变化趋势及墙体排水通道对墙后土体固结效果的影响。研究结果表明:横向排水通道对墙后土体固结效果的影响优于纵向排水通道对土体固结效果的影响,墙体底部横向排水通道的影响作用最显著;渗流作用下墙体应力由上往下呈先增大后减小的趋势,墙体下部所受最大水平剪应力最大。     

基于源质的煤基中间相小球体生成与可控演化

煤全组分族分离所得的密中质组是中间相小球体生成的来源物质（即源质）。以该源质为原料，制备煤基碳质中间相。考察了炭化过程中温度、恒温时间、氮气流速、原料进样方式和添加剂等因素对中间相小球体生成过程的影响，探讨了中间相小球体演化过程的可控性。结果表明：温度、恒温时间、进样方式是影响中间相小球体生成的主要因素，能够控制生成中间相小球体粒径大小；温度升高或恒温时间延长均会加剧原料分子的热反应，促进中间相小球体的生成和融并；大面积的融并将使粒度迅速增加，部分球体解体，球体数目下降，最终形成体中间相；进样方式主要通过影响小球体演化过程中挥发性气体的逸出及原料颗粒间热传递效率影响小球体的生成和发展；氮气流速起到辅助调控作用；添加剂的加入促进了原料成核，加速了小球体的生成。     

SiC单晶片切割力建模与自适应控制

Si C单晶因优良的物理和机械性能而大量用于大功率器件和IC行业。但由于材料的高硬度和高脆性,使其加工过程变得很困难。为此,分析了Si C单晶片切割过程,建立切割过程模型,通过F检验法进行系统阶次辨识,采用遗忘因子递推最小二乘算法在线估计模型参数,建立进给量与切割力的差分方程,设计基于最小方差自校正的切割力控制器,并进行实验验证。结果表明:控制器能够很好的跟踪不同信号,具有良好的鲁棒性,提高了Si C单晶片的加工效率和表面质量。     

Impact of regulatory rules on economic performance of PV power plants

The rapid growth of Renewable Energy Sources (RES) power plants connected to the grid has introduced new problems related to the safe and reliable operation of the electricity network from transmission to distribution sectors. New regulatory rules can promote RES producers to make a commitment on the energy amount that is likely to be supplied to the network. The present paper concerns the analysis of the energy production of a PV power plant from the economic point of view, with reference to the presence of regulatory rules. Costs of penalty and value of energy are compared, in order to evaluate the economic efficiency of the plant. Use of auxiliary energy storage devices is investigated, with the aim to determine the relevant dimensions that increase the economic efficiency of the PV plant. A software instrument that implements these algorithms is described and applied to a case study.     

千米深井大断面硐室双强壳体支护成套技术的应用

从分析深井高应力大断面巷道和硐室破碎围岩的变形破坏特点入手,指出巷道稳定性的控制机理在于及时强化失稳区围岩的残余强度,阻止初次失稳的发展,并施加高强的主动支护结构,从而使巷道进入二次稳定状态,同时采取高强的被动封闭支护技术。提出了全断面双强壳体支护设计、3S耦合协调支护设计和抗张拉强基础梁支护设计等设计方案来控制巷道变形。并对绞车房进行现场施工,支护效果良好,达到预期目标。     

Preparation and characterization of polynorbornene/sepiolite hybrid nanocomposite films

Polynorbornene/sepiolite hybrid nanocomposite films were prepared using polynorbornene dicarboximide and modified sepiolite with 3‐ aminopropyltriethoxysilane (3‐APTES). Exo‐N‐(3,5‐dichlorophenylnorbornene)‐5,6‐dicarboxyimide (monomer) and their copolymers were synthesized via ring‐opening polymerization using ruthenium catalysts. Subsequently, the surface‐modified sepiolite by 3‐APTES was mixed with the polynorbornene copolymers to prepare hybrid nanocomposite films. The modified sepiolite particles were well dispersed in N,N‐dimethylacetamide and distributed randomly throughout the polynorbornene matrix in the hybrid films, which enhanced the dimensional stability and mechanical and oxygen barrier properties of the polynorbornene/sepiolite hybrid nanocomposite films. © 2014 Society of Chemical Industry     

Influence of branching regularity on the behavior of hyperbranched polymers in solution

A carbosilane pseudo‐dendrimer with irregular structure and degree of branching DB = 1 was synthesized and fractionated. The molar masses of the obtained fractions ranged from 5000 to 490 000 g mol^?1. The hydrodynamic and conformational properties were studied by the methods of light scattering, sedimentation‐diffusion analysis and viscometry in dilute hexane and toluene solutions. The Mark ? Kuhn ? Houwink dependences were obtained. The results for the pseudo‐dendrimer are compared with the data for the initial hyperbranched poly(diallylcarbosilane) with DB = 0.5 and carbosilane dendrimer. It is shown that the solution properties of the pseudo‐dendrimer are close to those for the irregular hyperbranched polymer and differ significantly from the dendrimer behavior. Hence, it is branching regularity rather than the degree of branching that determines the conformational and hydrodynamic properties of hyperbranched polymers with a high degree of branching DB ≥ 0.5. © 2014 Society of Chemical Industry     

直接熔样正热电离质谱法测定二硼化锆中硼同位素丰度

本工作选择m/z88(23 Na210BO2+)和m/z89(23 Na211BO2+)的Na2BO2+作为检测离子,研究了同位素干扰、涂样技术、ZrB2样品处理等对硼同位素测定的影响,建立了快速准确测定ZrB2中硼同位素丰度的正热电离质谱法。实验复现了硼同位素标准物质的标准值,对酸溶法分解试样后涂样和直接熔融法涂样测量结果的精密度进行了比较。结果表明,采用直接熔融法涂样可以快速准确地测定ZrB2中硼同位素丰度,δ10B同位素丰度测定结果精密度优于0.020%。     

男装品牌研发竞争力评价指标体系研究

男装品牌研发竞争力的认知与管理是品牌实力强化运作中的关键。男装品牌研发竞争力的内容包括:研发投入、研发人才与研发形象、研发模式、研发待遇与政策等,其评价指标体系的认知及其构建是研究和讨论的重点。该系列研究成果将促使男装企业提升品牌认知水平和发展管理意识,更加理解品牌研发运作和竞争力管理的重要性,最终全面理解并重视应用研发竞争力的提升途径和方式方法。     

藏语拉萨话单音节嗓音声学参数分析

该文对藏语拉萨话单音节的嗓音特征进行了实验研究,实验首先对藏语拉萨话单音节进行语音标注,然后根据语音标注的位置信息,利用对应的程序提取音节结构中的元音和辅音的嗓音声学参数,对基频、开商和速度商分别统计分析,并做了显著性分析。实验结果表明不同元音和辅音的嗓音参数与发声方式以及其在音节中位置有关,元音和音节结构的不同会显著影响开商和速度商的值,但对于基频数据的影响并不显著。同时嗓音参数之间也存在一定的关联性,即基频和开商、速度商之间是反比关系,开商和速度商之间是正比的关系。