Abstract:本文研究石墨炉固体进样技术,应用内微型杯配合杯型石墨炉原子化器进行研究,发现涂镧的石墨内微型杯有使吸收脉冲峰出现时间延迟,将吸收峰移到炉最终平衡温度区,对固体进样能给出准确可靠的结果,精密度更好,测定人发中铜、锌的相对标准偏差约为5％。

Abstract:The method of the solid sample directly introducing the atomizer for determining the copper and zinc of man's hair is studied in this paper. With this method, we use coating Lanthanum inner mini-cup with Hitach 180-80 Zeeman Atomic Absorption Spectroscopy standard cup atomizer and predigestion. Overcomming long-time chemistry pretreatment, results are very satisfactory with optimum program conditions. This method has the advantages of accuracy and rapid and good repeatability. (relative standard deviation is about 5 precent).

Abstract:Hcl is used to remove MF4, Fe2O3 and part of FeO. The residue is dissolved by H2SO4-HF-H3PO4. Then, NH4Fe(SO4)2 is added to oxidate low-valence titanium and the standard solution of K2Cr2O7 is used to titrate Fe2+. The amount of total iron minus the amount of iron which has been removed, so that the amount of residue Fe2+ can be adjusted. This method has many advantages such as simplicity, rapidity repeatability.

Abstract:TiN is separated from orther Nitride by 1:2 Hcl, and the residue of TiN is heated with concentrated H2SO4-K2SO4 until the smoke rises from it followed by adding exceeded NaoH and by heating distillation. Using NaBr as electrolysis solution, the double platinum electrode is used to conduct the electrolysis. At the constent current of 30 mA. When it reaches the end point indicated by the dead stop method, record the time so as to calculrte the conten of TiN.

Abstract:Great accuracy can be obtained when metal iron is determined with bromine for dissolution K2Cr2O7 for titration. Unfortunately, harmful substances such as Br2, CH3OH, HgCl2, K2Cr2O7 etc. must be used when this method. But these harmful substances can be avoided when I2-C2H5OH is used for dissolution and EDTA for titration as discussed in this paper. As this method is simple with good reapetability, it is suitable for the diterminat ion of metal iron slag containing V.Ti, in slag containing high Ti, and in common slags.

Abstract:The lexical and syntex of Ada-sub and the compiler of Ada-sub and the method to realize it designed by us with the tool of YACC efficacious exploit on the Aim-l6 micro computer are discussed in this paper.

Abstract:In this paper,the open loop response curve is computed by a computer after the process paramter estimatio The parameters of PI or PID controller are computed by the method of respose curve. Then in order to obtain better control performance, the parameters of PI or PID controller are gradually optimized.This algorithm is with wider application range compared with the other self-tuning PID control algorithms. The computer simulation and real-time control trials shows a good result.

Abstract:The paper provides a detailed study of switching conditions of minimum-time control systems based on application in engineering. By analysis in theory and experiment, the authors deduce a set of switching conditions with state and control variabes inequality constraints, the variations of system parameters and the time-delay of computer in real time control. As an example, a DC motor speed control system is considered. By digital simulation and physical experiments,these conditions proved to be correct. The method in this paper is also suitable for other control systems using compound control algorithm.

Abstract:Steady-state probability, frequency and duration are the three main indices in reliability evaluation of the HVDC systems. Generally, they are solved by numerical methods. Their topolgical formulaes are derived by using the basic theory of ccates graph and considering conditions for some particularity of state-space in this paper. A set of generalised formulaes can be applied to obtain these indices expression about reliability parameters of components. Finally,an example is given to illustrate and verify this method.

Abstract:A new compensative snubber is presented for eliminating the surge current and high frequency parasitic oscillation in rectified circuit of the PWM DC-DC converters. The output surge and noise voltages are de-creased over 4/5. The working principle of the sunbber is analyesd in detail, the designing formulas are derived. The theoretic analysis is consistent with the experimental results.

Abstract:In this paper, a dynamic substructure method for analysing the transient response of the large structure is proposed. The method is based or, the combination of the reduced dynamic-stiffness composition method and the step-by-stop integration method. Its main feature is that the computational effort may be reduced significantly. Several examples are given to prove its reliability, effectiveness and accuracy.

Abstract:本文研究了0.20％C-0.52％Si-1.16％Mn-0.06％V的低合金钢在热轧与950℃淬火200℃,300℃,400℃,500℃和600℃回火的各种组织状态下的高应度低周循环软化和硬化行为。TEM观察结果表明,循环过程中位错数量和组态的变化以及碳化物的重溶导致材料硬化或软化。

Abstract:The modality analysis method is employed in this paper to study the influence of mass distribution on dynamic characteristics of a spindle system. It is found that there exist obvious difference between the influences of different mass distribution on the natural frequencies . and modality flexbilities of various order-mode. It is shown that the proportion of modality flexbility in the astatic flexbility can be equilibrated by means of adjusting correctly the mass distribution of the spindle system so that the cutting stability is improved as well. Experiment results are quoted to confirm, in a certain degree, the conclusion above.

Abstract:本文以我校研制的PDV-Ⅲ型、 PDV-Ⅰ型数字阀及其组成系统为对象,建立了它们的数学模型,提出了一种解液压系统非线性微分方程的实用型方法——变微分方程等数法,并以阶跃和脉冲输入,进行了动态数字仿真。所得的结论,具有一定的指导意义。

Abstract:This paper is aimed at investigating the acoustic properties of rock mass under the three-dimentional different stress states, and is presented to discuss emphatically the characteristics of the acoustic wave propagation and the stress-velocity relation in both rocks (sandstone and limestone) under uniaxial and true triaxial compression. The results indicate three regions in which the acoustic velocities and the strains change with the stresses are approximately similar under different stress states; and the acoustic velocity-stress relations for elastic rocks may be represented by different interdependence coefficients under uniaxial compression. At a time, The acoustic measurement method of rock mass stresses and the horizontal tectonic stress are discussed.

Abstract:本文利用对称形式的山路引理讨论下面的边值问题:和主要研究了λ在零点附近方程解的性态,证明了这时λ为(*)及(**)的无穷多重本征值。本文简报见[9]。

Abstract:In this paper, the Lagrangian method for thermal plant unit commitment and some properties of its Lagrangian multiplier are discussed. Besides, a polynomial algorithm for updating the Lagramgian multiplier is proposed, the critical point of operating unit commitment is derived, and the computational quatity is less than that of the method of subgradient. AS a result, the consumption of coal of the thermal plant is greatly reduced and greater economic benefits will gained.

Abstract:In this paper, the (PS)'c condition which is weaker than the (PS)' condition for mondifferentiable function is proposed. Correspondingly, the pseudogradient vector field is built and the first deformation lemma is proved. Therefore, all kinds of Minimax theorems including the famous Mountain pass lemma from them are derived. What is discussed in this paper is the generalization of the results of tee qaper.