金刚石车床的技术关键

金刚石车床与镜面铣床相比，其机械结构更为复杂，技术要求更为严格。除了必须满足很高的运动平稳性外，还必须具有很高的定位精度和重复精度。镜面铣削平面时，对主轴需很高的轴向运动精度，而对径向运动精度要求较低。金刚石车床则须兼备很高的轴向和径向运动精度，才能减少对工件的形状精度和表面粗糙度的影响。     

三坐标测量机测试精度的研讨

测量机的制造、安装和调试精度，测头精度，环境条件及其操作人员的技术水准是影响测量机测试精度的主要因素。文中介绍了这些因素对测量精度的具体影响及控制方法。     

一种摆布斗装置的工艺改进

本文介绍了一种摆布斗的工艺改进，通过对零件加工过程中产生的焊接变形及加工精度等问题进行分析，确认合理的加工工序，并对工装夹具进行改进，并利用数控卧式铣镗床的高精度，保证了零件的制造加工精度。     

修复机床主轴回转精度的方法

结合机床维修工作的特点，分析机床主轴与轴承精度对回转精度造成的影响，人为地控制各装配件径向圆跳动误差方向，达到提高主轴回转精度的目的。供同行参考。     

提高配料精度的措施研究

通过对影响配合饲料生产工艺中配料精度的因素进行了理论和实例分析。研究结果表明，合理选择配料工艺参数，根据配料精度的要求，采用适当的控制过程，并进行容错处理后，可以提高配料精度。     

基于时间误差的灌装精度概率及可靠度计算模型

描述了定量杯定量灌装机的灌装时间与灌装精度的关系，推导出实际灌装时间的理论计算公式。针对实际存在的各种随机变量对灌装时间的影响，建立了灌装时间的概率模型，提出基于灌装时间随机误差的灌装精度概念以及灌装精度可靠度概念，并相应建立出灌装精度概率模型与灌装精度可靠度计算模型。模型的建立使定量分析与计算灌装时间的随机误差、灌装精度以及灌装精度可靠度成为可能。另外，模型的建立使准确确定灌装时间成为可能，并为在此基础上制定紧凑的灌装工作循环周期提供了可靠的依据。     

基于灌装时间随机误差的灌装精度概率模型与可靠度计算模型

描述了灌装时间与灌装精度的关系，针对实际存在的各种随机变量对灌装时间的影响，建立了控制液定量长管式灌装机的灌装时间的概率计算模型。提出基于灌装时间随机误差的灌装精度及其可靠度概念，并相应建立出灌装精度概率模型与灌装精度可靠度计算模型。     

提高木工刨床切削刃位置精度对策

文章分析刨床装刀精度与切削刃位置精度的意义及其区别，提出了提高切削位置精度的若干对策，选择适应的刀头与立轴联结方式；使用对刀器提高装刀精度；采用切削刃磨齐工艺，结论指出：制造厂根据有关条件绘制铣削切痕值和有效切削刃判定值表。用户要根据木制件表面粗糙度与相关条件选定切削刃位置精度及装刀精度。     

KTC型切丝机主传动链精度分析及反求设计

切丝宽度的精度是衡量切丝机的最重要的性能指标之一。《卷烟工艺规范》规定：切出梗丝的偏差为±０．０３ｍｍ；切出叶丝的偏差为±０．１ｍｍ。现在国内普遍使用的有引进的ＫＴＣ型切丝机和国产化的ＲＣ４型切丝机。本文通过对ＫＴＣ型切丝机有关切丝精度的主传动链精度理论分析，建立切丝机内联系传动链的运动方程，导出传递函数式。在此基础上，针对传动链中出现的主要误差因素及其对切丝精度的影响，合理地对传动构件进行精度分配。     

仓储货架立柱产品精度控制分析与研究

仓储货架主要部件立柱的产品精度将直接影响到整个库房货架结构的稳定性和安全性，对立柱所需板带的预冲孔精度和板带冷弯成型精度进行研究，结果表明：影响立柱产品精度的关键因素为预冲孔板带的平整度和直线度，以及板带的材料特性，如抗拉强度、延伸率等。通过对文中所列试样实物的实际生产试验和分析，使检、试验人员判定仓储货架立柱产品的质...     

窖泥中总酸、总酯和总醛测定方法的研究

窖泥是生产白酒的关键材料,窖泥的成分复杂,主要有醇类、酸类、醛类、酯类、酚类及芳香族化合物等。本研究建立了一种窖泥中总酸、总酯和总醛的快速连续测定方法,该方法所得3种物质的标准曲线线性关系良好,精密度试验相对标准偏差（RSD）值分别为1.81%、1.13%、0.887%,稳定性试验RSD值分别为1.35%、1.22%、0.96%,加标回收率平均值分别为98.10%、98.16%和98.69%。结果表明,该方法适合窖泥中总酸、总酯和总醛的测定,对白酒的窖泥发酵生产起到一定的指导意义。     

酵母基因组的提取

酵母是低等真核生物,被广泛应用于食品生产和基因工程。提取酵母基因组对于应用酵母进行实验研究非常重要,本文摸索出了一套简单、经济、高效的酵母基因组的提取方法,为进行酵母研究提供方便。     

Principles of Microwave Combination Heating

Faster, automated cooking of foods with improved quality can be realistically achieved only by a combination of heating modes such as microwave, infrared, and hot air, which, by themselves, have limitations. Combining heating modes poses many technical challenges. To meet these challenges, comprehensive understanding of microwave combination heating is needed. This article is the synthesis of the most fundamental‐based approaches (theoretical and experimental) in an attempt to provide the most succinctly said principles that can be useful to a product or process designer in a very practical sense. To obtain these principles, characteristics of various individual modes of heating are discussed and principles of combining them are deduced based on the behavior of the individual modes.     

制革污泥中总重金属的厌氧生物毒性探究

制革污泥中含有多种重金属,其中铬为重要的特征重金属。为探究制革污泥中的总重金属对制革污泥进行厌氧生物降解的影响,本文就此进行了相关研究。试验结果发现制革污泥总重金属对污泥产甲烷活性有较大影响,随着污泥中总重金属浓度的提高,污泥的产甲烷活性明显降低,并且产气能力恢复缓慢,但在毒性试验中基本不产气的试样在恢复试验中有了少量产气的出现,表明制革污泥中总重金属对厌氧生物的毒性属于生理毒素。     

Some Textile Applications of Finite-element Analysis Part I: Finite Elements for Aligned Fibre Assemblies

A new approach to the application of finite elements to aligned-fibre-assembly problems is introduced. This more rigorous application of finite-element analysis will allow the solution of a range of problems that have been impossible to solve by using previous approaches. Difficulties with non-linear material properties and large-scale deformations are overcome by defining the element stiffness matrix in a co-ordinate system based on the energy modes of the element deformation. It is shown how algorithms can be used to supply non-linear relationships for various types of deformation, simplifying the task of using complex material properties. The transformation of the element properties back to a conventional co-ordinate system to allow assembly of all of the elements in the structure is presented.

A two-dimensional element is developed to model aligned fibre assemblies. To maintain fibre continuity between finite elements, twelve degrees of freedom are required for each element. The deformation modes of this element are derived in terms of the conventional co-ordinate system. The results from the finite-element analysis are compared favourably with measurements taken from a deformed array of springs.

This paper is the first part of a series of two papers. Part II will investigate the application of finite elements to yarn mechanics.     

制革过程中氨氮和总氮产污系数的试验模拟核算

通过实验室模拟制革过程,测定各工序原料水、废水及洗皮废水中的氨氮和总氮,并结合典型制革企业废水氨氮与总氮实测,分析制革废水氨氮与总氮的主要来源及产污特征,并进行产污系数核算。结果表明:氨氮主要来源于各工序所加化料,且各工序分布不均。以上研究为制革废水中氨氮处理提供了基本理论与依据。     

姜黄素介导的光动力冷杀菌方法对牡蛎杀菌的效果研究

通过光动力疗法（photodynamic therapy,PDT）对牡蛎肉匀浆及牡蛎肠道中的细菌进行杀灭处理,探究PDT可否杀灭牡蛎中的细菌。结果表明,以姜黄素为光敏剂的光动力冷杀菌处理对牡蛎中细菌具有非常好的灭活效果,3、6 h光敏剂富集组对牡蛎的杀菌率可达90%以上。同时该方法处理简便,且具有广谱杀菌特性。     

Effects of mixing on fed-batch fermentation of L-ornithine

The effects of mixing on L-ornithine fermentation were studied using an L-arginine auxotrophic mutant of Brevibacterium ketoglutamicum ATCC 21092. Three different modes of fed-batch culture using two different impeller types were studied in a 7 l fermentor. The first two modes of fed-batch culture were carried out in a fermentor equipped with six-flat-blade disk-turbine impellers with top and bottom feeding. The third mode of fed batch culture was carried out using pitched-six-flat-blade disk-turbine impellers with top feeding. The titre of L-ornithine increased up to 1.8 fold with bottom-feeding or when the pitched-six-flat-blade disk-turbine impellers were used compared to when the six-flat-blade disk-turbine impellers with top-feeding were used. It was observed that the mixing time of the limiting nutrients varied significantly depending on both the direction of feeding and the impeller type. Since the profiles of the specific rates of CO2 evolution, oxygen and glucose uptakes were very similar for the three culture modes, it could be reasonably assumed that the microorganism exhibited similar growth rates for each mode used. However, different amino acid producing activities were observed in the three culture modes. From these results it is concluded that the productivity of L-ornithine fermentation is significantly improved by shortening the mixing time of the limiting nutrient in the fermentor.     

On the Dynamic Performance of Flax Fiber Composite Beams Manufactured at Different Relative Humidity Levels

ABSTRACT

Development of environment-friendly natural fiber composites has been a recent trend. However, due to the fact that natural fibers permit high level of moisture absorption from the surroundings, it can lead to weak bindings and degradation of composite properties. This paper presents an experimental study on the dynamic performance of flax fiber composite beams manufactured at different relative humidity (RH) levels. Five types of flax fiber-reinforced composite materials were made under different RH values, i.e., dry, 35%, 50%, 70%, and 95% RH, and beam samples were prepared using the composite. Impact hammer testing was conducted to measure the natural frequencies and damping of the beams. It was found that for the first three modes, while the resonant frequencies are very close for most samples, there is a clear drop of frequencies for the composite fabricated at 95% RH. Along with an increase of the RH level, the damping ratios for all the three modes have reported a slight increase, but the variation is not significant.     

Effects of mixing on fed-batch fermentation of -ornithine

The effects of mixing on -ornithine fermentation were studied using an -arginine auxotrophic mutant of Brevibacterium ketoglutamicum ATCC 21092. Three different modes of fed-batch culture using two different impeller types were studied in a 7 l fermentor. The first two modes of fed-batch culture were carried out in a fermentor equipped with six-flat-blade disk-turbine impellers with top and bottom feeding. The third mode of fed batch culture was carried out using pitched-six-flat-blade disk-turbine impellers with top feeding. The titre of -ornithine increased up to 1.8 fold with bottom-feeding or when the pitched-six-flat-blade disk-turbine impellers were used compared to when the six-flat-blade disk-turbine impellers with top-feeding were used. It was observed that the mixing time of the limiting nutrients varied significantly depending on both the direction of feeding and the impeller type. Since the profiles of the specific rates of CO₂ evolution, oxygen and glucose uptakes were very similar for the three culture modes, it could be reasonably assumed that the microorganism exhibited similar growth rates for each mode used. However, different amino acid producing activities were observed in the three culture modes. From these results it is concluded that the productivity of -ornithine fermentation is significantly improved by shortening the mixing time of the limiting nutrient in the fermentor.