基于顾客偏好的瓶装水外观感性质量评价

从感性质量评价的角度提取13个感性质量评价词对,用于全面且针对性地评价顾客对瓶装水的偏好.以"想购买"为综合感性提取瓶装水的感性质量评价要素,结合聚类分析等方法确定7种代表性样本.基于语义差异法构建瓶装水感性质量评价量表,运用多元回归模型分析建立顾客偏好与感性评价词对之间的关系模型.关系模型解决了如何识别顾客偏好和感性质量需求,以及如何将这些偏好和需求整合到产品设计过程中的问题.     

刚-塑性圆柱薄壳拉拔中考虑流体动力润滑的解

引言对于金属材料拉拔与挤压时的流体动力润滑问题,近年来国外学者做了一些工作。一般都以板形条料或圆形杆件为主。可是,对于薄壳的拉拔与/或挤压时的动力润滑问题至今还很少涉及。本文企图将等厚度圆柱薄壳通过...     

Thickness-averaged model for numerical simulation of electroosmotic flow in three-dimensional microfluidic chips

The microfluidic system is a multi-physics interaction field that has attracted great attention. The electric double layers and electroosmosis are important flow-electricity interaction phenomena. This paper presents a thickness-averaged model to solve three-dimensional complex electroosmotic flows in a wide-shallow microchannel/chamber combined (MCC) chip based on the Navier-Stokes equations for the flow field and the Poisson equation to the electric field. Behaviors of the electroosmotic flow, the electric field, and the pressure are analyzed. The quantitative effects of the wall charge density (or the zeta potential) and the applied electric field on the electroosmotic flow rate are investigated. The two-dimensional thickness-averaged flow model greatly simplifies the three-dimensional computation of the complex electroosmotic flows, and correctly reflects the electrookinetic effects of the wall charge on the flow. The numerical results indicate that the electroosmotic flow rate of the thickness-averaged model agrees well with that of the three-dimensional slip-boundary flow model. The flow streamlines and pressure distribution of these two models are in qualitative agreement.     

Analysis of Second-Harmonic Generation of Low-Frequency Dilatational Lamb Waves in a Two-Layered Composite Plate

We analyze the effect of second-harmonic generation(SHG) of primary Lamb wave propagation in a two-layered composite plate, and then investigate the influence of interfacial properties on the said effect at low frequency. It is found that changes in the interfacial properties essentially affect the dispersion relation and then the maximum cumulative distance of the double-frequency Lamb wave generated. This will remarkably influence the efficiency of SHG. To overcome the complications arising from the inherent dispersion and multimode natures in analyzing the SHG effect of Lamb waves, the present work focuses on the analysis of the SHG effect of low-frequency dilatational Lamb wave propagation. Both the numerical analysis and finite element simulation indicate that the SHG effect of low-frequency dilatational Lamb wave propagation is found to be much more sensitive to changes in the interfacial properties than primary Lamb waves. The potential of using the SHG effect of low-frequency dilatational Lamb waves to characterize a minor change in the interfacial properties is analyzed.     

轧带的润滑力学分析

本文耦合了流体动力润滑理论,经典轧制理论及弹性接触变形理论,并计入了润滑油的压粘效应和轧制材料的硬化效应等因素,运用有限元法和边界元法等计算方法,分别得到了刚性轧辊下的理论解、弹性轧辊下的Boussinesq解及边界元解,预示了轧带工作区的压力、剪应力以及膜厚的分布规律,确定了最小油膜厚度,并对计算结果与实验结果进行了比较。     

考虑粘压效应的两圆柱EHL非线性问题的有限元解

主要符号裹石赫芝压力区半宽E:,石,拉压弹性模量 1I“‘=人汤o滩m inH~H。二H二;nN矛PP= 1/l一川_1一次、=二居一-二二一十—. 2\七:七:/“:,“2圆柱圆周线速度。=之(“, 。:) 2详E产油膜厚度中心处油膜厚度 最小油膜厚度汤/R二人。/R=hm。。/R单元插值函数油膜压力户/E‘RZ圆柱半径~l)孕答君’R~李十李 入i代2 弹性变形留单位宽度上的载荷砂二兰止. E,R,整体坐标x,出口边界位置X一x/ba粘压系数拜润滑油粘度砰。进口处润滑油粘度aL,口2泊松比RI,1一R一、引言 齿轮、凸轮、滚柱轴承等机件的润滑问题,可模拟成承受一定载荷,具有一定…     

考虑粘压效应的两圆柱弹性流体动力润滑问题的非线性解

本文应用有限元法,通过简单迭代和牛顿迭代,成功地求解了计入弹性变形和粘压效应在内的非线性代数方程组.在未作任何压力分布假设的情况下,得到了协调解,包括油膜形状,并具有第二次压力尖锋的压力分布解.文中叙述了边界条件的处理和迭代方法的使用.为这类问题的求解,提供了一种收敛精度高、适用范围宽的计算技巧.     

衡阳市经济增长与环境质量关系的探讨

根据衡阳市1991—2005年间污染物浓度和排放量，采用环境库茨涅茨曲线研究方法，对衡阳市经济增长指标人均GDP与排污量和环境质量指标的关系进行了实例研究。结果表明：衡阳市经济发展与环境质量和污染物排放量的关系没有固定的模式。有效的污染治理措施有利于例U型曲线的转折点的提前出现，从而达到经济增长与环境质量改善同步的目标。     

横向电容自耦式紫外预电离开关

对紫外预电离技术在气体开关方面的影响进行原理研究,分析并实验验证电容并联的横向辅助电极对主开关进行紫外预电离的可行性。辅助电极击穿释放紫外光,通过光电效应在主开关表面产生初始电子,以减小主开关的击穿电压离散度。预电离效果与辅助电极击穿导通电流的峰值强度、辅助电极两端的电压以及预电离储能电容有关,优化这些参数可以提高光照强度来增强预电离效果。实验结果表明:当主开关内部充满氮气、分压电容为pF量级时,距离主电极15 cm远的横向辅助电极可以产生预电离效应。在此基础上,提出一种新型的横向型电容自耦式紫外预电离开关的设计。     

高效液相色谱法测定庆大霉素普鲁卡因维B12胶囊中维生素B12的含量及含量均匀度的评价

提出了高效液相色谱法测定A厂、B厂、C厂和D厂等4个厂家47个批次庆大霉素普鲁卡因维B12胶囊样品中维生素B12的含量,并对4个厂家相同批次或不同批次的样品中维生素B12含量的均匀度进行了评价.用水提取胶囊内容物中的维生素B12,以CAPCELL PAK ACR C18色谱柱为分离柱,以不同比例混合的甲醇和0.028 ...