地应力及其测量法简介

地应力对工程岩体的稳定性影响很大，工程实践中常需定量地确定工程范围内的地应力。本文简要地介绍了地应力的概念、应用及常用的测量方法。     

换热网络数值模拟稳定性分析

换热网络的数值模拟在换热网络的定量分析中起着重要作用。但在模拟计算中,有时表现出数值稳定性差。提高数值稳定性的方法,目前多通过改善算法来实现。本文通过对换热网络数值模拟的误差分析,提出了误差放大因子的概念,并依此选择迭代变量。通过对迭代变量的选择,达到提高换热网络数值模拟稳定性的目的。     

Stability analysis of double-diffusive solar ponds with non-constant temperature and salinity gradients

In this communication, the stability of the double-diffusive solar ponds with non-uniform temperature and salinity gradients has been investigated. This is a further generalization of our approach to this problem initiated in Ref. [7]. Using a stochastic approach, the linearized system of basic equations of motion is reduced to a single integro-differential equation. For convective motion, this equation reduces to a time-independent Schrödinger equation for a particle moving in a potential field ƒ(Z) characterized by the non-uniform temperature and salinity gradients. This equation can, in general, be solved (exactly or approximately depending on the form of the gradient profile) by methods commonly used in quantum mechanics.

In the Appendix, we show that, for a quadratic gradient profile, the above equation has an analytical solution similar to that obtained by Zangrando using numerical computations.     

An experimental and numerical study of hunting in thermostatic-expansion-valve-controlled evaporators

The dynamic behaviour of a thermostatic-expansion–valve (TEV)-controlled dry-evaporator is studied experimentally and numerically. Although the linear model of the TEV together with the distributed model of the evaporator is able to predict the stable dynamic response of the system adequately, it fails to reproduce the hunting behaviour that is observed under certain operating conditions. A scrutiny of the experimental data reveals the possible existence of hysteresis in the system. The distributed model including the experimentally determined input-output characteristics of the TEV is able to reproduce the main features of the hunting oscillations well. The amplitude and frequency of these oscillations depend on the static superheat setting, the heat load of the evaporator and the time constant of the TEV bulb.     

新疆茶藨中紫红色素的萃取工艺及稳定性研究

本文介绍了新疆野生植物茶子果实中,紫红色素提取及定性检验和色素的提取工艺。     

Fundamentals of stability testing

The principles on which stability tests are based are reviewed. The need to differentiate between product stability and product-container compatibility is emphasized. Recognition of this distinction is fundamental to the efficient organisation and execution of stability tests.
Attention is also drawn to the desirability of having for every product a release specification with which it must comply when manufactured and a broader check specification with which it must comply throughout its shelf-life.
Test methods and the interpretation of the data accrued throughout a test are also discussed.
It is concluded that stability tests should not be conducted in accordance with a standardized routine pattern but that the objectives of each test should be defined and the test designed to achieve those objectives in the most efficient way.
Les regles fondamentales des essais de stabilite     

蚕庄金矿倾斜采场的地压研究

本文使用工程地质、室内试验及数值分析的方法对蚕庄金矿的倾斜矿房的地压活动规律进行了研究，得出了一些有价值的结论。     

The stability robustness determination of state space models with real unstructured perturbations

This paper considers the robust stability of a linear time-invariant state space model subject to real parameter perturbations. The problem is to find the distance of a given stable matrix from the set of unstable matrices. A new method, based on the properties of the Kronecker sum and two other composite matrices, is developed to study this problem; this new method makes it possible to distinguish real perturbations from complex ones. Although a procedure to find the exact value of the distance is still not available, some explicit lower bounds on the distance are obtained. The bounds are applicable only for the case of real plant perturbations, and are easy to compute numerically; if the matrix is large in size, an iterative procedure is given to compute the bounds. Various examples including a 46th-order spacecraft system are given to illustrate the results obtained. The examples show that the new bounds obtained can have an arbitrary degree of improvement over previously reported ones. This work has been supported by the Natural Sciences and Engineering Research Council of Canada under Grant No. A4396.     

银行UPS供电系统可靠性方案探析

本文从银行UPS供电系统总体设计、UPS设备选型主要考虑参数、冗余方式选择、UPS系统的安装、维护等方面进行综合考虑 ,论述提高银行UPS供电系统的可靠性、稳定性的方法 ,以期保障银行业务分分秒秒不间断进行     

Effect of storage temperature on phenolics stability in hawthorn (Crataegus pinnatifida var. major) fruits and a hawthorn drink

The stability of five major phenolics, namely (−)-epicatechin (EC), procyanidin B₂ (PC-B₂), chlorogenic acid (ChA), hyperoside (HP) and isoquercitrin (IQ), in hawthorn fruits and a canned hawthorn drink were evaluated during 6 months of storage in the dark at three different temperatures (4, 23 and 40 °C). HPLC with a diode-array detector was used to determine the contents of the individual compounds. The results showed that the studied phenolics in the hawthorn fruits and the drink were both stable at 4 °C and relatively unstable at 23 and 40 °C with varied extents of degradation. At room temperature (23 °C), marked degradations of EC and PC-B₂ were observed in both the fruits and the drink with around 50% and 30% decrease after a 6-month storage, respectively. A more significant decrease of the phenolics was observed at 40 °C, especially for EC and PC-B₂, which were almost completely degraded after a 6-month storage. HP, IQ and ChA were relatively stable at 23 °C, but unstable at 40 °C. Therefore, low-temperature storage is recommended for maintaining the quality and efficacy of hawthorn fruits and its preparations.