氯离子扩散系数快速测试方法综述

氯离子扩散系数是评价混凝土结构抗氯离子渗透性能和使用寿命的重要指标,选择一种快速、准确的测试方法至关重要.本文以非稳态电迁移实验(Rapid Chloride Migration,RCM)为基准,与国内外常用的几种氯离子扩散系数快速测试法比较,总结每种方法的特点及适用范围,建立RCM法与其他测试方法的相关性.结果表明:...     

Fault magnitude estimation for processes

In this paper, the fault isolation and fault magnitude estimate methods are proposed. In the original fault isolation methods, contribution plots are popular. However, it is not accurate. In the original fault estimation methods, the authors assume that the fault magnitude is far greater than the normal measurement. However, the assumption is too strong. To avoid the above two problems, in this paper, the fault is isolated by determining the fault direction and the fault magnitude is estimated using the fault reconstruction. The proposed methods are used to Monte Carlo simulation and the electrical smelting magnesium furnace. From the simulation results, we can see that the proposed methods can solve the problems mentioned above effectively.     

Compressibility factor of sour natural gases

This paper presents a comparison of twelve selected methods for the prediction of the compressibility factor of natural gases containing H₂S and CO₂. The methods are compared with experimental data from the published literature and with previously unpublished data made available by oil and gas companies operating in Alberta. The method of Robinson, Macrygeorgos and Govier, and the method of Robinson and Jacoby are found to be most accurate over the range tested here. A brief desription of the twelve methods considered is also presented. Three new methods are also proposed. Two of the proposed methods are modifications of the Pitzer method and the Redlich-Kwong equation of state. These methods are suitable for digital computer applications. The third method proposed here is developed for hand calculations. The new methods presented here are superior to the twelve methods tested in this study.     

二羟基苯磺酸钙两种滴定分析方法比较

地２,５－二羟基苯磺酸钙的含量分析方法进行了探讨,比较了配位滴定法与氧化的滴定法的测定准确程度及其实用性,并最终确定了可靠、准确的测定方案。     

直流电桥法测量电缆故障点的距离

迅速、准确地探测故障点的位置对保证故障电缆的及时修复有着重要意义。介绍了电缆故障的性质和直流电桥法测量电缆故障点距离的原理，着重阐述了几种常用的电缆接地故障的测量方法，并提出在实际生产、施工中，应根据具体情况选取合理的仪器及测量方法，迅速、准确地探测故障点的位置，以保证故障电缆的及时修复。     

The quasi-stationary state approximation in polymerization kinetics

The errors incurred in free-radical chain addition polymerizations through the use of the popular quasi-stationary state approximation (QSSA) under severe, but fairly common, reaction conditions are examined in detail, and simple, useful criteria for applicability of the QSSA are proposed. The conditions examined are “dead end” polymerization, polymerization with hindered termination and nonisothermal polymerization. It is concluded that the proposed criteria are reasonably accurate and that in most known free-radical polymerizations only hindered termination might possibly lead to appreciable errors through application of the QSSA.     

Genetic Architecture and Molecular,Imaging and Prodromic Markers in Dementia with Lewy Bodies: State of the Art,Opportunities and Challenges

Dementia with Lewy bodies (DLB) is one of the most common causes of dementia and belongs to the group of α-synucleinopathies. Due to its clinical overlap with other neurodegenerative disorders and its high clinical heterogeneity, the clinical differential diagnosis of DLB from other similar disorders is often difficult and it is frequently underdiagnosed. Moreover, its genetic etiology has been studied only recently due to the unavailability of large cohorts with a certain diagnosis and shows genetic heterogeneity with a rare contribution of pathogenic mutations and relatively common risk factors. The rapid increase in the reported cases of DLB highlights the need for an easy, efficient and accurate diagnosis of the disease in its initial stages in order to halt or delay the progression. The currently used diagnostic methods proposed by the International DLB consortium rely on a list of criteria that comprises both clinical observations and the use of biomarkers. Herein, we summarize the up-to-now reported knowledge on the genetic architecture of DLB and discuss the use of prodromal biomarkers as well as recent promising candidates from alternative body fluids and new imaging techniques.     

One-point determination of intrinsic viscosity for polycarbonate,poly(phenylene oxide), and polyetherimide

Intrinsic viscosity determination for polymers can be simplified and considerable time and effort saved via a single measurement of relative viscosity at a known concentration. Several workers have proposed one-point intrinsic viscosity methods. Of the methods in the literature, two one-point methods were found to be as accurate as the multiple-point graphical extrapolation procedure. These two methods, one due to Solomon and Ciuta and a nomographic technique due to Khan and Bhargava, were successfully applied for the intrinsic viscosity determination of three polymers: polycarbonate, poly(phenylene oxide) and polyetherimide.     

塑料热水管及其性能评价

本文介绍了几种常用的塑料热水管及其性能评价方法，并对进一步发展塑料热水管提出了建议。     

Variations in diffusion coefficient of disperse dyes in single PET fibres: monitored and interpreted by confocal laser scanning microscopy

A novel method is proposed for determining the diffusion coefficient (D) of disperse dyes in PET fibres. Concentration-distance profiles are recorded on optical sections of single fibres by confocal laser scanning microscopy. This allows for an accurate value of the true diffusion coefficient in the fibres as well as for a founded insight in the dye diffusion process and its interrelation with the glass transition, which is not possible by the commonly used methods. At 130 °C, the common industrial dyeing temperature, the diffusion coefficient showed to be constant for the dyes tested, with D being about five times larger for the anthraquinone dye than for the benzodifuranone dye. At 100-110 °C, near to the start of the glass transition region of the fibres, D could no longer be regarded as a constant for the anthraquinone dye but was concentration dependent. This was explained by the plasticising effect of the anthraquinone dye.     

一种求解化工动态优化问题的迭代自适应粒子群方法

智能优化方法因其简单、易实现且具有良好的全局搜索能力,在动态优化中的应用越来越广泛,但传统的智能方法收敛速度相对较慢。提出了一种迭代自适应粒子群优化方法（IAPSO）来求解一般的化工动态优化问题。首先通过控制变量参数化将原动态优化问题转化为非线性规划问题,再利用所提出的迭代自适应粒子群优化方法进行求解。相比传统的粒子群优化方法,该种迭代自适应粒子群优化方法具有收敛速度更快的优点,主要原因是：该算法根据粒子种群分布特性自适应调整参数;该算法通过缩减搜索空间并迭代使用粒子群算法搜索最优解。将提出的迭代自适应粒子群方法应用到多个经典动态优化问题中,测试结果表明,该方法简单、有效,精度高,且收敛速度比传统粒子群算法有显著提升。     

A new method for solving initial value problems

A more accurate method (comparing to the Euler, Runge–Kutta, and implicit Runge–Kutta methods) for the numerical solutions of ordinary differential equations (ODEs) is presented in this paper. The coefficients in the approximate solution for the ODE using the proposed method are divided into two groups: the fixed coefficients and the free coefficients. The fixed coefficients are determined by using the same way as in the traditional Taylor series method. The free coefficients are obtained optimally by minimizing the error of the approximate solution in each time interval. Examples are presented to compare the numerical solutions of the Rahmanzadeh, Cai, and White's method (RCW) to those of other popular ODEs methods.     

Comparison of methods for the determination of glycerol by acetylation

Summary A method for the determination of glycerol has been presented in which the acetylation is performed with a reagent consisting of acetic anhydride in pyridine. Typical data obtained by this procedure and other accepted methods are shown. The proposed procedure is simpler, more rapid, and more accurate than the conventional acetin method.     

Quantitative determination of metal cations chemisorbed by polycaproamide fabrics

Studies were conducted to develop a method of quantitative determination of metal cations chemisorbed by fabrics made of polycaproamide fibres. A complexonometric method was selected to determine the cation content. Complexonometric methods, which are highly accurate, approaching the accuracy of gravimetric methods, require much less time for execution. A single method is proposed for determining the amount of different metal cations chemisorbed by synthetic materials. The reproducibility of the results is good.     

Water sorption kinetics in light‐cured poly‐HEMA and poly(HEMA‐co‐TEGDMA); determination of the self‐diffusion coefficient by new iterative methods

The present investigation is concerned with the determination of self‐diffusion coefficient (D) of water in methacrylate‐based biomaterials following Fickian sorption by two new methods: the Iterative and the Graphical methods. The D value is traditionally determined by means of the initial slope of the corresponding sorption curve and the so‐called Stefan's approximation. The proposed methods using equations without approximations and data resulting from the whole sorption range reach to accurate values of D, even when the sorption curve does not present an initial linear portion. In addition to D, the Graphical method allows the extrapolation of the mass of the sorbed water at equilibrium (M_∞), even when the equilibrium specimen's mass fluctuates around its limited value (m_∞). The test of the proposed procedures by means of ideal and Monte Carlo simulated data revealed that these methods are fairly applicable. The obtained D values compared with those determined by means of the Stephan's method revealed that the proposed methods provide more accurate results. Finally, the proposed methods were successfully applied to the experimental determination of the diffusion coefficient of water (50°C) in the homopolymer of 2‐hydroxyethyl methacrylate (HEMA) and in the copolymer of HEMA with triethylene glycol dimethacrylate (98/2 mol/mol). These polymers were prepared by light curing (λ = 470 nm) at room temperature in presence of camphorquinone and N,N‐dimethylaminoethyl methacrylate as initiator. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

基于LabVIEW的电动执行机构测试台

基于虚拟仪器（LabVIEW）对电动执行机构的测试台进行智能化设计,叙述调试台的工作原理,提出电动执行机构相关技术参数的测试与计算方法。实际生产应用证明,此测试台功能齐全,测试速度快,技术参数测试准确。     

Model-free real-time optimization of process systems using safe Bayesian optimization

Conventional real-time optimization (RTO) requires detailed process models, which may be challenging or expensive to obtain. Model-free RTO methods are an attractive alternative to circumvent the challenge of developing accurate models. Most model-free RTO methods are based on estimating the steady-state cost gradient with respect to the decision variables and driving the estimated gradient to zero using integral action. However, accurate gradient estimation requires clear time scale separation from the plant dynamics, such that the dynamic plant can be assumed to be a static map. For processes with long settling times, this can lead to prohibitively slow convergence to the optimum. To avoid the need to estimate the cost gradients from the measurement, this article uses Bayesian optimization, which is a zeroth order black-box optimization framework. In particular, this article uses a safe Bayesian optimization based on interior point methods to ensure that the setpoints computed by the model-free steady-state RTO layer are guaranteed to be feasible with high probability (i.e., the safety-critical constraints will not be violated at steady-state). The proposed method can thus be seen as a model-free variant of the conventional two-step steady-state RTO framework (with steady-state detection), which is demonstrated on a benchmark Williams-Otto reactor example.     

涂装前表面粗糙度测量值与规范值的对比性探讨

阐述表面粗糙度的几个主要参数及定义,介绍了国内管道防腐测量表面粗糙度的常用测量仪器和方法,分析了规范值的意义和各种测量仪器的测量结果与标准参数的关系,对管道防腐涂装表面粗糙度测量方法提出了建议。     

定位分布贡献方法估算有机物正常沸点

A new position group contribution model is proposed for the estimation of normal boiling data of organic compounds involving a carbon chain from C2 to C18. The characteristic of this method is the use of position distribution function. It could distinguish most of isomers that include cis- or trans-structure from organic com-pounds. Contributions for hydrocarbons and hydrocarbon derivatives containing oxygen, nitrogen, chlorine, bro-mine and sulfur, are given. Compared with the predictions, results made use of the most common existing group contribution methods, the overall average absolute difference of boiling point predictions of 417 organic com-pounds is 4.2 K; and the average absolute percent derivation is 1.0%, which is compared with 12.3 K and 3.2% with the method of Joback, 12.1 K and 3.1% with the method of Constantinou-Gani. This new position contribution groups method is not only much more accurate but also has the advantages of simplicity and stability.     

安全阀在线调试中阀座有效面积的反算法

在研究安全阀在线调校原理和化工企业生产特点的基础上,解决了安全阀在线调试过程中起跳压力计算的难点,即阀座有效面积的计算。提出了两种较实用的阀座有效面积的计算方法。经过对安全阀实际调校的检验,证明这两种方法是高效、精确的计算方法。