Freezing of strawberry pulp in large containers: experimental determination and prediction of freezing times

Strawberry pulp packed in bulk in containers of various shapes and of large sizes (10–2001) was frozen in a tunnel at −35°C. Time-temperature curves and freezing times for heat transfer in one, two and three dimensions were obtained. Experimental freezing times were compared with predicted values given by approximate methods based on two different equations for the calculation of freezing times in slabs, which in turn used three different methods for the calculation of shape factors. The predicted results obtained in this work confirmed that both the simplified prediction methods of freezing times and the shape factors used were sufficiently accurate for the design of freezing equipments for these types of product and working conditions.     

中国内地、香港、澳门继承法律适用规则研究

中国内地、香港、澳门之间区际继承关系法律冲突明显，其可行的解决方法就是采用区际冲突法的方法。目前，解决区际继承法律冲突的重点是解决冲突法的冲突。因此，对内地、香港和澳门的继承法律适用规则进行比较研究和分析十分必要，在研究基础上提出有益合理的规则建议。     

Evaporation of R407C and R410A in a horizontal herringbone microfin tube: heat transfer and pressure drop

Based on experimental data for R134a, the present work deals with the development of a prediction method for heat transfer in herringbone microfin tubes. As is shown in earlier works, heat transfer coefficients for the investigated herringbone microfin tube tend to peak at lower vapour qualities than in helical microfin tubes. Correlations developed for other tube types fail to describe this behaviour. A hypothesis that the position of the peak is related to the point where the average film thickness becomes smaller than the fin height is tested and found to be consistent with observed behaviour. The proposed method accounts for this hypothesis and incorporates the well-known Steiner and Taborek correlation for the calculation of flow boiling heat transfer coefficients. The correlation is modified by introducing a surface enhancement factor and adjusting the two-phase multiplier. Experimental data for R134a are predicted with an average residual of 1.5% and a standard deviation of 21%. Tested against experimental data for mixtures R410A and R407C, the proposed method overpredicts experimental data by around 60%. An alternative adjustment of the two-phase multiplier, in order to better predict mixture data, is discussed.     

利率、投资、储蓄和货币供给量的协整分析

根据西方利率决定理论,利用协整模型和误差修正模型对利率、投资、储蓄、货币供给量的内在关系进行了定量分析,发现利率、投资、货币供给量以及储蓄之间确实存在长期共同趋势,并且具有短期共同波动模式。这对我国利率市场化和充分利用利率杠杆调节宏观经济具有重要的指导意义。     

一种感应电动机软起动算法的建模与仿真研究

针对异步电动机的常规起动方法,在晶闸管交流调压电路技术不断成熟的基础上,提出了一种新的软起动算法,利用Matlab软件建立仿真模型,并进行仿真研究。仿真结果证明了该算法的正确性和可行性。此算法为三相异步电动机实现无级、平滑起动提供了理论基础。     

Practical investigations of two-stage bacon tempering

Bacon has to be tempered (part-frozen) before it can be sliced in a high-speed slicing operation. Traditionally the desired slicing temperature was achieved in a long single-stage process. Increasingly a two-stage process of heat removal followed by temperature equalisation is used to reduce processing time and weight loss. The objectives of the work described in this paper were:

To provide practical design data for a two-stage bacon-slicing operation.

To provide data that could be used in the development and verification of a model that would help optimise current and new tempering systems.

     

正篇:势·场·道——对中国建筑的整体感悟

本文通过对中国建筑的整体感悟,提出了势·场·道概念,简述了三者的关系,以求对中国建筑有一个更为本质的把握。附篇提出西部建筑五论,即:契源论、灾变论、积悖论、离元论和归宗论。     

均匀设计及偏最小二乘回归法在高渗乳油研制中的应用

以实例说明如何在高渗乳油制剂研制中应用均匀设计和偏最小二乘回归法。以制剂不含渗透剂与含有渗透剂时的润湿时间差值（Y1）、渗透时间差值（Y1）作为试验指标，以20％三唑磷高渗乳油配方研制为例．应用均匀设计法设计试验方案，对试验结果采用偏最小二乘回归法，以因变量最大值为优化方向，同时对两个试验指标进行回归建模，得到Y1与各渗透剂含量回归模型及Y1与各渗透剂含量回归模型，模型拟合的决定系数R^2分别为0．9883、0．9978。最优目标函数值Y1、Y2分别为176．21s、137．18s，实测值分别为176．10s、137．11s。     

基于RSM和GA的涡轮熔模铸造工艺优化

以涡轮熔模铸件浇注系统设计为例,基于BOX-BehnKen设计响应面试验(RSM)建立了二阶响应面模型,探究了浇注系统半径、高度与浇注温度对铸件内部缺陷的体积和缺陷与铸件表面之间的距离的影响,并利用遗传算法(GA)优化工艺参数。数值模拟分析结果表明,该优化方案可以在得到无缺陷涡轮铸件的同时达到80.53%的工艺出品率,为熔模铸造浇注系统的设计优化提供思路。     

建筑采暖设计软件HPM的应用

HPM是PKPM系列建筑、结构、水暖电集成化CAD系统中采暖设计软件。该软件具有自动化程序高,制图、计算一体化的特点,实际工作中,软件本身有些局了性。通过对HPM的使用,提出了HPM软件在采暖设计工作中存在的问题,以及相应的解决方法,为设计工作的顺利进行提供了帮助。