和利时MACS^TM系统在涂料制备车间的应用

介绍了和利时公司的MACSTM系统在涂料制备车间的应用,着重描述系统的主要技术特色以及系统控制功能的实现。     

LTI连续时间系统零状态响应的求解方法

目前国内很多"信号与系统"的教材中讨论了LTI连续时间系统零状态响应的一些求解方法,本文根据现有的信号与系统教材中连续时间系统零状态响应的求解方法,分别从利用冲激响应与激励的卷积、微分方程和变换域三方面求解零状态响应,并给出了实例说明了其正确性。     

Stability of two-time scale linear stochastic hybrid systems

The problem of exponential mean-square stability of two-time scale, linear stochastic hybrid systems has been studied in this paper. To obtain the sufficient conditions of stability, two basic approaches of stability analysis: for one-time hybrid systems with a Markovian switching rule as well as switching rule and singularly perturbed nonhybrid systems, were combined. The Lyapunov techniques were used in both approaches.     

A plate capacitor model of the EDM process based on the field emission theory

The electrical discharge machining (EDM) process is, by far, the most popular amongst the non-conventional machining processes. The technology is optimum for accurate machining of complicated shapes in hard materials, required in the modern industry. However, although a lot of EDM machines are widely applied for many years, fundamental knowledge of the process is still limited. The complex nature of the process involves simultaneous interaction of thermal, plasma temperature and electromagnetism factors, which makes the machining process modeling very difficult. In this paper, based on the analysis of the electric discharge machining (EDM) process, a plate capacitor model is constructed to describe the discharging process in a pulse time. The whole EDM process is divided into four stages, successively as interelectrode electric-field establishment, electric discharge channel formation, stable EDM and deionization, the interaction of each stage and the distribution function of EDM energy are deduced using the field electron emission theory. For the purpose of analyzing the effect of the single factor, a set of machining through-hole experiments were carried out and investigated. The study shows that critical electric-field intensity and the effective discharging time rate play major roles on the improvement of machining efficiency; the model can explain the differences of machining efficiency using different materials of tool pole and different EDM parameters; and the theoretical results are concordant with the experimental data well.     

牛皮浸灰过程毛纤维的变化

采用热台显微镜对牛皮浸灰过程中毛纤维的表面形态及耐热性能进行了研究。结果表明,随浸灰时间的增加,毛纤维的表面破坏明显严重,纤维的干热收缩温度基本相同,但最终收缩率降低,热稳定性提高。     

Lime mud from paper-making process addition to food waste synergistically enhances hydrogen fermentation performance

The effect of lime mud from paper-making process (LMP) addition on the H₂ fermentation of food waste (FW) was investigated. It was found that a slight addition of LMP (1.0–4.0 g in 200 g FW) significantly enhanced the H₂ fermentation performance, not only increasing the total amount of H₂ produced but also accelerating the whole reaction, shortening the lag period, and increasing the H₂ production rate. Fermentation stability and microbial germination were also facilitated by LMP addition. This was attributed to the existence of Ca, Fe, Mn and alkaline substances such as CaCO₃ and NaOH. The batch process treating a mixture of FW and LMP was showed that the highest hydrogen production of 137.6 mL H₂/g VS was achieved at final pH 5.0, adding 3 g LMP (in 200 g FW) to the fermentation process, which lag-phase time was about 2.5 h.     

牛皮箱板纸工艺控制的研究

对牛皮箱板纸生产过程中的常见问题提出了解决途径，并从生产的角度介绍如何制造高质量的牛皮箱板纸。     

基于统计分析的发酵溶解氧与二氧化碳关系的研究

由理论分析及经验得到溶解氧与尾气二氧化碳模型,通过布拉酵母菌发酵得到实测溶解氧及尾气二氧化碳检测数据,依据经验模型计算出近似溶解氧值。应用统计分析软件SPSS得到实测溶解氧与二氧化碳及计算溶解氧的Pearson相关系数分别为-0.632和0.862,说明溶解氧与尾气二氧化碳之间存在负相关关系,而经验模型计算的溶解氧值与实际溶解氧之间具有较强的相关性。进一步采用曲线拟合对计算溶解氧值进行修正,使其更接近实际溶解氧。     

Rapid synthesis of submicron crystalline barium zirconate BaZrO3 by precipitation in aqueous basic solution below 100 °C

Pure crystalline BaZrO₃ powders can be produced by precipitation in highly basic aqueous solution. The influence of several synthesis parameters is studied. At high OH^? concentration ([NaOH] = 20 mol/l), it is possible to obtain the well-crystallized stoichiometric perovskite phase at relatively low temperature (～80 °C), after a short reaction time (15 min) and without requiring any precaution to avoid the presence of CO₂. This synthesis method yields spherical particles, whose size can be controlled by changing the concentration of the Ba + Zr solution. No calcination treatment is necessary since the precipitate is crystalline. Suitable choice of the synthesis parameters ([NaOH] = 20 mol/l, [Ba + Zr] = 1 mol/l, reaction time = 15 min) yields a sub-micron precipitate with excellent densification behaviour. Corrosion tests in BaO–CuO melt show that ～98% dense BaZrO₃ obtained by sintering at 1650 °C for 13 h could be used for crucibles in the synthesis of YBa₂Cu₃O₇ superconducting single crystals.     

An investigation on shape memory behaviours of hydro-epoxy/glass fibre composites

Shape-memory polymers (SMPs) have the capacity to return large strains by external stimuli. Among various SMPs, shape-memory epoxy has received considerable attention because of its superior mechanical and thermal properties as well as excellent shape-memory performance. In this study, short glass fibre-reinforced shape-memory hydro-epoxy composites are developed to improve further the mechanical property of shape-memory epoxy resin. The thermomechanical and shape-memory properties of the developed composite materials are investigated by dynamic mechanical analysis, bend test and shape recovery test. The results indicate that the glass modulus and bend strength of the developed composite materials initially increase and then slightly decrease with increasing short glass fibre content. The glass transition temperature of the developed composite materials does not change with increasing short glass fibre. When the short glass fibre content is less than 4.5 wt.%, full recovery can be observed after only several minutes at different temperatures. The shape-memory property of the composite materials is not affected greatly. However, when the short glass fibre content is more than 4.5 wt.%, the material would be destroyed after deformation.