高炉渣中非晶态定量方法的比较分析

 利用观察法、岩相法和X射线衍射法定量分析了某钢厂高炉渣中非晶态含量,得到该高炉渣中非晶态含量大于95%的结论。三种方法中,观察法最简单,但易受人主观因素影响;岩相法需要一定的经验来判断;利用X射线衍射法可以较客观定量高炉渣中非晶态含量。     

辐射离散坐标法在柱形炉膛中的辐射传热计算

利用离散坐标法对圆柱形炉膛辐射传热进行了计算,结果与计算精确的区域法的计算结果符合较好;同时又利用离散坐标法和热流法对旋流燃烧室温度场进行比较计算,结果表明:离散坐标法计算结果与文献中实验结果符合较好;离散坐标法具有较好计算精度,可应用旋流燃烧辐射计算中.     

静态留矿采矿法在缓倾斜矿体开采中的应用

目前玲珑金矿采矿方法主要为浅孔留矿采矿法,但由于玲珑矿田内部分矿体的产状为缓倾斜且上下盘均不稳固,传统的浅孔留矿采矿法不适用于缓倾斜矿体的开采,为此,在回采矿房内留有处于静止不动状态的部分矿石,以支撑围岩,防止其破坏和脱落,保证安全回采.介绍了静态留矿采矿法的采场结构及回采工艺,应用实践表明,采矿损失率4.8％,矿石贫...     

Monogenic determinants of familial Alzheimer''s disease: presenilin-1 mutations

The authors describe a new simple noniterative, yet efficient method to estimate the risk ratio in studies using case-parental control design. The new method is compared with two other noniterative methods, Khoury's method and Flanders and Khoury's method, and with a maximum likelihood-based method of Schaid and Sommer. The authors found that the variance of the new estimation method is usually smaller than that of Khoury's method or Flanders and Khoury's method and that it is slightly larger than that of the maximum likelihood-based method of Schaid and Sommer. Despite the slightly large variance of the new estimator compared with that of the maximum likelihood-based method, the simplicity of the new estimator and its variance makes the new method appealing. When genotypic information for only one parent is available, the authors also describe a method to estimate the risk ratio without assuming Hardy-Weinberg equilibrium or random mating. A simple formula for the variance of the estimator is given.     

机械搅拌法与镁喷吹法铁水搅拌能和混匀时间的关系

采用永田进治公式和全浮力模型计算了机械搅拌法和喷吹法的铁水搅拌能,研究了搅拌能和混匀时间的关系,并和水模型的结果进行了比较,分析了两种搅拌能影响混匀时间的原因。结果表明,机械搅拌法的搅拌能力比喷吹法大数倍,在同一搅拌能下机械搅拌方式的混匀时间比喷吹法短。搅拌优势使得机械搅拌法比喷吹法的脱硫率比喷吹法平均高18.61%,带来的副作用是铁水温降要高于喷吹法15℃,以及对耐火材料的侵蚀速度为喷吹法的3倍。     

Nonlinear Buckling of Composite Shells of Revolution

By adopting the energy method, a method of calculating the stability of the rotational composite shell is presented that takes into account the influence of nonlinear prebuckling deformations and stresses on the buckling of the shell. The relationships between the prebuckling deformations and strains are calculated by nonlinear Karman equations. The numerical method is used to calculate the energy of the whole system. The nonlinear equation is solved by combining the gradient method and the amended Newton iterative method. A computer program is also developed. Examples are given to demonstrate the accuracy of the method presented in this paper.     

Approximation of M Function for Partially Penetrating Wells

A computationally simple approximation of the Hantush M function is proposed. Using this approximation, an optimization method is proposed for identifying the aquifer parameters from early drawdowns around partially penetrating wells. The aquifer parameters are hydraulic conductivity and specific storage. The application of the method is illustrated using a field example. The proposed method results in a 120-fold saving in time when compared to the prior method. It is hoped that the proposed approximation and method will be of help to the field engineers and practitioners.     

Method for Quantifying Freshwater Input and Flushing Time in Estuaries

A method is developed to quantify total freshwater input and flushing time in estuaries using measured flow and salinity data at the estuary-ocean boundary. A formula is derived to calculate the volume of mixed estuarine water that leaves the estuary on the ebb tide. The calculated volume of mixed estuarine water, along with the volume of new ocean water that enters the estuary on the flood tide, is used to quantify the total volume of freshwater input. The calculated volume of mixed estuarine water is also used to quantify the flushing time. The developed method is applied to Barnegat Bay, N.J. The volume of freshwater input calculated from the new method compares well with that estimated using watershed, aquifer, and meteorological data. The flushing time calculated from the new method is between that calculated from the classical tidal prism method and that from the fraction of freshwater method. An assessment is made on the sensitivity of calculated values to the quality of measured data at the estuary-ocean boundary. The volume of freshwater input and the flushing time calculated from the developed method are highly reliable when there is a significant salinity difference between flood and ebb tides.     

纯银含银量分析方法的误差及改进

本文研究现有分析方法的误差及改进方法．ＮａＣｌ溶液的加入量使用称重法．消除了移液管加液的偶然误差,用电位滴定法代替比浊法,原子吸收法消除了氯化银部分溶液造成的系统误差．新分析方法具有较高的精密度．     

Crack Growth Prediction by Manifold Method

The prediction of crack growth is studied by the manifold method. The manifold method is a new numerical method proposed by Shi. This method provides a unified framework for solving problems dealing with both continuums and jointed materials. It can be considered as a generalized finite-element method and discontinuous deformation analysis. One of the most innovative features of the method is that it employs both a physical mesh and a mathematical mesh to formulate the physical problem. The physical mesh is dictated by the physical boundary of a problem, while the mathematical mesh is dictated by the computational consideration. These two meshes are interrelated through the application of weighting functions. In this study, a local mesh refinement and auto-remeshing schemes are proposed to extend the manifold method. The proposed model is first verified by comparing the numerical results with the benchmark solutions, and the results show satisfactory accuracy. The crack growth problems and the stress distributions are then investigated. The manifold method is proposed as an attractively new numerical technique for fracture mechanics analysis.     

Colony size can be used to determine the MIC of fluconazole for pathogenic yeasts

This report describes a new statistical method for estimating the MIC of fluconazole for yeasts pathogenic to humans. This method is based on comparison of the colony sizes on solid media containing different concentrations of fluconazole. By this method, the MICs of fluconazole for 10 yeast strains were comparable to results obtained by the standard method recommended by the National Committee for Clinical Laboratory Standards. This method is simple to perform and easy to interpret. The turnaround time is faster than other methods. The method should be applicable to the determination MICs of other antifungal drugs for yeasts.     

高效加工宽曲面的一种新方法

改变传统使用加工中心加工宽曲面的加工方法,而是创新采用了一种新方法,较以前大大的提高了加工效率,降低了加工成本,是一种值得加工类似宽曲面推广的新方法.     

基于油中溶解气体分析的电力变压器故障诊断

介绍变压器故障诊断的改良三比值法。针对改良三比值法的不足,提出了基于改良三比值法的综合诊断,并且设计了与之相关的编程流程图。与改良三比值法相比较,此方法具有更好的故障识别效果。     

Extended Use of Linear Graph Theory for Analysis of Pipe Networks

Linear graph theory used for pipe network analysis is to make the method systematic. A numerical method that uses linear graph theory is presented for the steady-state analysis of flow and pressure in a pipe network including its hydraulic components (pumps, valves, junctions, etc.). The proposed method differs from other linear graph methods in terms of the linear graph and the selection of its tree. The solution algorithm uses a function that depends on a power law to update the pipe flows in successive iterations. The exponents of this function are chosen to obtain a fast convergence rate even for large errors in the assumption of initial pipe flows. The convergence rate of the proposed method is validated using an error function and is compared to those of other methods. Some typical networks are analyzed to check the reliability of the proposed method. The results demonstrate the superior conditioning of the proposed method.     

露天铀矿山爆区品位估算方法优选研究

爆区品位估算是露天铀矿山极其重要的日常性工作。为快速、准确地得到品位估算结果,从估算方法选取展开研究,介绍了最近距离法、距离幂次反比法和普通克里格法等品位估算方法的基本原理。以国外某铀矿为例,采用上述估算方法和三维矿业软件开展了爆区品位估算试验,并以普通克里格法的估算结果为标准,对最近距离法和距离幂次反比法的估算结果进行了偏差、统计和图形分析。结果表明：在矿石量和平均品位方面,与普通克里格法所得的估算结果相比,距离幂次反比法的偏差较小,而最近距离法的偏差较大;在估值准确性方面,距离幂次反比法基本接近普通克里格法,且估值精度满足矿山实际生产的要求,可用于爆区估值,而最近距离法的估值精度相对较差,不能用于爆区估值。距离幂次反比法作为爆区品位估算方法,操作过程简单且参数相对确定,在满足估值精度要求的同时可节约建模时间。该研究成果可为类似露天铀矿山进行爆区品位估算提供一定的指导。     

Discontinuous Galerkin Finite-Element Method for Simulation of Flood in Crossroads

A numerical solution of the two-dimensional Saint Venant equations is presented for the study of the propagation of the floods through the crossroads of the city. The numerical scheme is a Runge-Kutta discontinuous Galerkin method (RKDG) with a slope limiter. The work studies the robustness and the stability of the method. The study is organized around three aspects: the prediction of the water depths, the location of the right and oblique hydraulic jumps in the crossing, and especially the distribution of the flow discharges in the downstream branches. The objective of this paper was to use the RKDG method in order to simulate supercritical flow in crossroads and to compare these simulations with experimental results and to show the advantage of this RKDG method compared to a second-order finite-volume method. A good agreement between the proposed method and the experimental data was found. The method is then able to simulate the flow patterns observed experimentally and to predict accurately the water depths, the location of the hydraulic jumps, and the discharge distribution in the downstream branches.     

火焰原子吸收光谱法测定铜及铜合金中微量镍

采用硫代硫酸钠掩蔽主体铜,主体铜不分离,用酒石酸抑制铁,锑等生成氢氧化物沉淀,以三氯甲烷萃取镍与丁二酮肟形成的络合物,经1 mol/L盐酸反萃后,用火焰原子吸收光谱法测定。方法操作简便易掌握,检测限可达0.000 05%、方法回收率为98%以上,精密度0.002%镍时变异系数为2.2%。     

Assessment of DNAse activity by the rivanol clot method

A method for assessing DNAse activity in various biological substrata is offered. It is based on the capacity of rivanol to form a clot with DNA inversely proportionate to depolymeraization of DNAse under the effect of nucleases of different origin. The sensitivity of the method is more than 10 times higher than of viscosimetry and the alcohol clot formation test. In addition, the new method permits quantitative assessment of the clot, with the detection performed by any colorimetric or fluorimetric method. The method is adapted to measurement of the activities of commercial DNAse preparations, serum and immunoglobulin DNAse, and bacterial nuclease activities.     

Optimizing Aquifer Parameters from Drawdowns in Large Diameter Wells

An optimization method is proposed for estimating the storage coefficient and transmissivity of an aquifer from drawdowns in large diameter wells consequent to an unsteady pumping. The concept of an optimal time step size is propagated in the proposed method. The estimate of the aquifer parameters corresponding to the optimal time step size is termed final estimate. The estimates for any other time step size are not reliable. The proposed method can also take into account the residual drawdowns. The application of the method is illustrated using an example.