低排放燃烧室燃料空气预混均匀性研究

为了解决燃料与空气均匀预混的问题,以气态燃料-低排放塔式同轴分级燃烧室为研究对象,采用数值模拟与实验设计数理统计方法相结合,研究了主燃级叶片角、叶片数、燃料速度和单面孔数对燃料和空气预混特性的影响,筛选出对燃料空气预混均匀性影响的显著项,并拟合得出均匀性的预测公式。结果表明：单面孔数及其平方项对预混均匀性影响最大;燃料速度与叶片角、燃料速度与单面孔数的交互效应其次;叶片数、叶片角、燃料速度及其平方项和交互项对均匀性的影响最小。     

A robust design to reduce variability in glass container inspection

This article presents research efforts made to assist a Fortune 500 glassmaker in reducing the variability of its automated visual inspection systems in assessing product quality. Through interviewing line workers, engineers and managers, and direct observations of the inspection process possible causes leading to large variability observed in the inspection process were identified. Responding to these findings, solutions related to equipment setup, job changes, and operational procedures were suggested in order to minimize the inspection process variations as well as to improve the replicability of the inspection stations. Additionally, a unique statistical experiment was conducted to analyze how three factors (namely, operator, defect size, and threshold value used) would affect the mean of the defective ratio. A robust design aiming at controlling these variations was then given to optimize the system's performance.     

颗粒铁除铬试验研究

采用批实验方法,研究颗粒铁（铁屑）加入量、Cr（Ⅵ）初始浓度及阴离子组分对颗粒铁去除铬动力学影响。结果表明,在室温条件下（24℃±2℃）,不调节溶液的pH值,铁能很快去除水中的铬;随颗粒铁加入量的增加、初始Cr（Ⅵ）浓度的减少,颗粒铁对铬去除增强,较高浓度时,氯离子、硫酸根离子和重碳酸根离子对颗粒铁除铬有适度的增强;低浓度时,HCO3^-轻微减弱颗粒铁对Cr（Ⅵ）的去除。探讨了各因素对铬去除的影响机理。     

Visualization Approaches for Evaluating Ridge Regression Estimators in Mixture and Mixture‐Process Experiments

When the component proportions in mixture experiments are restricted by lower and upper bounds, the input space of a designed experiment space can become an irregular region that can induce multicollinearity problems when estimating the component proportion parameters. Thus, ridge regression provides a beneficial means of stabilizing the coefficient estimates in the fitted model. Previous research has focused on using prediction variance as a metric for determining an appropriate value of the ridge constant, k. We use visualization techniques to illustrate and evaluate ridge regression estimators and the robustness of estimation with respect to the variance and the bias. The addition of bias allows better balancing between the stability of the estimators and minimally changing the estimates. We illustrate the graphical methods with mixture and mixture‐process examples from the literature. Copyright © 2014 John Wiley & Sons, Ltd.     

Thermal diffusivity and porosity of solid materials by the electromagnetic ultrasonic technique. Part 3—simultaneous measurement of ultrasonic velocity and thermal diffusivity

The objective of this study is to evaluate simultaneously the time dependence of the thermal diffusivity of carbon-carbon composites (C/C composites) and their porosity during heat treatment using the electromagnetic ultrasonic technique. This paper describes two kinds of experiments conducted to confirm the principle for simultaneous measurement of both the ultrasonic velocity (used to evaluate the porosity) and the thermal diffusivity at room temperature. For each material, the samples used in both experiments were identical. The ultrasonic velocity of type 304 stainless steel and its thermal diffusivity were 5.85 km/s and 3.8 mm²/s with precisions of ±1.6 and ±8 percent, respectively. The ultrasonic velocity of a two-dimensional woven C/C composite and its thermal diffusivity were 2.86 km/s and 4.8 mm²/s with precisions of ±5.0 and ±8 percent, respectively. The results appear to indicate that the electromagnetic ultrasonic technique can measure the ultrasonic velocity and the thermal diffusivity simultaneously and that it is also applicable to C/C composites. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(5): 308–322, 1996     

核主成分回归方法在电力负荷中期预测中的应用

在分析核主成分回归原理及其与最小二乘方法关系的基础上,针对电力负荷中期预测的影响变量间存在着的非线性关系信息,提出使用主成分网归方法进行电力负荷中期预测,一定程度上解决了误差传播的问题,系统的预测精度得到了提高。使用核主成分同归进行了模型实验,探讨了模型训练样本选取、数据处理、参数选择和训练方法等方面的问题,井对实验结果进行了分析讨论。实验表明,在模型不很复杂的情况下,可以使用直接搜索的方法有效地设置应提取的非线性主成分个数p的值。     

谐波驱动柔性关节机械臂接触力的动态特性

谐波驱动柔性关节机器人在约束空间的接触力的动态特性与接触环境刚度密切相关,环境刚度不同导致其动态特性不同,这与机器人自身动力学特性、传感器动态特性以及环境刚度等动态特性有关.通过对单自由度谐波传动系统接触力建模、理论分析,可知谐波传动接触力的动态特性与环境刚度密切相关,当环境刚度较大时,输出力基本取决于谐波齿轮柔性关节变形的负载力.基于建立的谐波驱动系统实验平台,利用动态信号分析仪进行了接触力的模型实验辨识研究,得到从电机驱动器到力传感器输出的动态特性模型,为接触力控制器设计提供参考.从实验辨识结果验证了理论分析的正确性,并在单纯速度反馈作为主动阻尼情况下,辨识得到接触力的闭环频率响应特性,根据闭环频响可知速度反馈阻尼可以增加系统力控制的稳定性.     

Vortex characteristics due to nozzle clogging in water caster mould: modelling and validation

In continuous slab casting, clogging in the submerged entry nozzle (SEN) ports leads to flow asymmetry and vortex formation in the mould. Knowledge of vortexing and its influence on product quality is fundamental for defect-free production. In this study, the interconnected effects of nozzle clogging and SEN submergence depth, variation on flow asymmetry and vortex characteristics in a 0.4 scale water caster have been characterised by CFD investigation and validated with experimental results from the authors’ previous work. Mean flow velocities at the sub-meniscus and near the port exit predicted by the computational model are compared with the time-averaged values of the impeller probe velocity measurements and found to be in reasonable agreement. Three different clogging conditions (0, 33 and 66% in the left port of the SEN) for SEN submergence depth of 60?mm are studied and the 66% clogging produced vortices having largest diameter, which is consistent with the experimental observations. The effects of SEN submergence depth on flow asymmetry and vortexing are investigated with three different conditions – 40, 60 and 80?mm. It is found that the shallow SEN submergence depth (40?mm) produces vortices of largest diameter and the flow is most stable for a SEN submergence depth of 60?mm among the three cases. Vortex bending towards the SEN as noticed in the experimental observations is also observed in the computational study. This work illustrates the possibility of capturing features of vortexing using validated CFD model.     

低泡精练剂HS—QC在纯棉织物精练中的应用

介绍了低泡精练剂HS—QC应用性能,探讨了低泡精练剂HS—QC在整个精练过程的泡沫状态,研究了低泡精练剂HS—QC的精练效果,结果表明：该精练剂是一种低泡、性能优良的精练剂。     

超声波辅助复合酶法提取枸杞多糖工艺研究

以枸杞为试验材料,研究了超声波辅助复合酶（脂肪酶/蛋白酶/纤维素酶/果胶酶=1:1:1:1）提取枸杞多糖的工艺条件。以枸杞多糖得率为评价指标,通过正交试验确定了最佳提取条件为料液比1∶40（g∶mL）,提取温度50 ℃,超声时间50 min,复合酶添加量0.5%。在此最佳条件下,枸杞多糖平均得率为58.910%。