圆形离心浮选机的研究与应用

圆形离心浮选机是由自吸式气泡发生器和圆柱—圆锥形分选槽体组成的浮选设备 ,利用矿浆射流形成的离心力场强化了重力场中的气泡碰撞矿化和泡沫析出过程。工业试验结果表明 :圆形离心浮选机对煤泥特别是细煤泥的浮选效果好 ,具有浮选速度快 ,分选选择性好 ,单位容积处理能力大等优点 ,是实现微细矿物分选的有效设备     

转向柱管承载能力的试验研究

在分析转向柱管花键部位应力集中情况的基础上,通过对某厂生产的转向柱管扭转破坏的试验研究,得到如下结论:①转向柱管的承载能力与其外花键齿与方向盘中心内花键齿之间的非接触区长度有关,以花键端部过渡圆弧的直径大小为宜;②安装方向盘总成时所施加在安装螺母上的拧紧力矩在70N.m左右时,转向柱管的承载能力最大。     

Improvement of oxygen mass transfer estimation from oxygen concentration measurements in bubble column reactors

An original procedure has been established for estimating the overall volumetric mass transfer coefficient using the oxygen concentration curves resulting from the usual gassing-in and gassing-out method. This procedure was applied to experimental data obtained in a small scale bubble column using both tap water and a coalescence-inhibiting liquid mixture that represents the coalescence behavior of biological media. It is based on the analysis of the characteristics times of the system, including those of the hydrodynamics of the two phases, the sensor dynamics and the system inertia when the gas composition is modified. A numerical procedure was developed to estimate the characteristic time of the system inertia t_i, using the assumption that this inertia is nearly independent of superficial gas velocity U_G. The calculations confirmed that the optimized t_i value was nearly independent of U_G and of the coalescence behavior of the liquid phase. Additionally, the resulting K_La_L values for tap water were closer to the correlation of Shah et al. [1982. Design parameters estimations for bubble column reactors. A.I.Ch.E. Journal 28, 353-379] than those of other conventional models. Finally, the original procedure was also reported to reduce significantly the square sum deviation between the predicted and the measured oxygen response curves.     

基于变轴力和定轴力试验对比的钢筋混凝土柱恢复力滞回特性研究

在讨论了框架柱在地震作用下轴力变化规律的基础上,通过由变轴力柱和定轴力柱的低周交变加载试验获得的恢复力滞回曲线对比,给出了用各个“轴力变化半周”的“等效滞回轴力”修正恢复力骨架曲线,和用“等效累积滞回轴力”随时间步长调整累积强度退化系数从而修正恢复力滞回曲线的再加载刚度的建议。该建议能更有效、更方便地反映轴力变化的整个历程对变轴力柱恢复特征的影响,有利于提高钢筋混凝土杆系结构非弹性地震反应分析的有效性。     

精馏塔静态仿真：Ⅰ.静动态混合数学模型的应用

本文为了克服精馏塔静态仿真不易收敛和初值难以给定等难题，巧妙地利用隐含数值积分方法的特点，将稳态与动态数学模型耦合起来，用以求解高难度的非理想精馏塔静态仿真问题。所得静动态混俣模型大大提高了精馏塔静态仿真的鲁棒性，对于高度非理想精馏塔的仿真尤为有效。通过对某丙烯腈萃取精馏塔的静态仿真，充分证明了这种混合模型化方法的可行性。     

The Lazy Cook Problem, or Scheduling Two Parallel Machines to Optimize Vehicle Utilization

A cook has to prepare n cakes using an oven with two racks. According to the recipe, the i-th cake has to be baked for exactly a _i minutes. Cakes to be cooked are taken from a table and carried to the oven, and once cooked are carried back to the table by means of a trolley that can carry two cakes at a time. What is the minimum number q ^* of round trips required of the cook? This problem has application to the operation scheduling of transportation systems and to material cutting. A different problem arises according to whether the cook accepts or not to stay near the oven for awhile with the trolley. If the trolley cannot be idle at the oven, an optimum schedule with no oven idle-time always exists: consequently, the trolley schedule is trivial, and the problem is transformed into a set packing. For this case, we propose and test a heuristic method which generates all of the promising columns of the set packing, and solves the resulting problem by branch-and-bound. Instead, if the trolley can be idle at the oven for a limited amount of time, a problem arises to find an optimal schedule of the trolley: in this case we show how to use a scaling technique in order to obtain a very good feasible solution by the method above.     

活性炭单柱提取肌苷新技术研究

活性炭单柱提取肌苷新技术研究李永泉，张进，姚恕，郑莲英，俞峰（杭州大学生物系杭州３１００２８）（浙江大学化工系杭州３１００２７）关键词：肌苷，提取技术，活性炭单柱１前言目前，国内肌苷发酵后处理工艺落后，在分离提取工序中肌苷损失严重，收率一般只有５０％...     

灭蚊窗涂剂的毛细管柱气相色谱分析

介绍了用AT-101毛细管柱，以邻苯二甲酸二正戊酯为内标，对灭蚊窗涂剂中3种有效成分残杀威、氯菊酯、氯氰菊酯同柱同条件下定量分析的方法。该方法的分析时间短，准确度、精密度高，重现性好。     

双氧水冷漂助剂液中润湿剂的分离和鉴测

双氧水冷漂助剂液中的润滑剂——烷基硫酸钠可以在四级氧化铝柱上用氯仿和乙醇—水的淋洗体系进行分离而获得纯品;用NMR和GC法进行结构分析;两相滴定法测定其含量。     

Effect of Li+ ions on structure,properties, and actuation of cellulose electro‐active paper actuator

We have reported an electro‐active paper actuator from regenerated cellulose. After dissolving cellulose fibers with a solution of lithium chloride in N,N‐dimethylacetamide, cellulose was regenerated by combining distillation of cellulose solution along with washing with the mixture of deionized water, isopropyl alcohol, and running water. However, the effect of Li⁺ ions on structure, properties, and the actuation behavior of the actuator was not studied. This article describes the changes in these parameters when the Li⁺ ions are removed by subjecting it to different running water exposure time. The structure and properties of cellulose electro‐active paper and its actuation behavior were studied. As Li⁺ ions content reduced from 4354.17 to 10.26 ppm by increasing the exposure time of running water, crystallinity, Young's modulus, and bending displacement decreased. Details about the investigation have been explained. This elimination of ions is important to increase the piezoelectric effect in EAPap by decreasing the ion migration effect. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008