A mathematical model of kinetics of carbide layer formed on the surface of steel in fused system was set up with the theory of non-stable diffusion mass transfer and regular solution sub-lattice. This model was analyzed and testified by the experiments in which the VC layers were formed on four kinds of steels as steel 45, 4Cr5Mo-SiV1, T10, and Crl2MoV immersed in the V2O5-Na2O-B2O5 fused system with the reducing agent of silicon. The results showed that there was a good agreement between the model and the experimental results; the growth speed of carbide layer depended on the factors of carbon activity in substrate, treatment temperature, kinds of carbides and its structure

In lecture D2 we introduced the position velocity and acceleration vectors and referred them to a fixed cartesian coordinate system. While it is clear that the choice of coordinate system does not affect the final answer, we shall see that, in practical problems, the choice of a specific system may simplify the calculations considerably. In previous lectures, all the vectors at all points in the trajectory were expressed in the

Chapter 3 Technology of Electronic Commerce 3.1 A short history of the Internet and the web The Internet was the result of some visionary thinking by people in the early 1960s who saw great potential value in allowing computers to share information on research and development in scientific and military fields. J CR Licklider of MIT, first proposed a global network of computers in 1962, and moved over to the Defense Advanced Research Projects Agency(DARPA) in late 1962 to head the work to develop it Leonard Kleinrock of MIT and later UCLA developed

Equilibrium between slag and molten iron at 1600℃ was investigated for the direct alloying of steel with Nb2O6-bearing slag. The activity of niobium oxide in the slag was measured. The αNb2O5 is in the range of 10-2-10-4. TheδNb2O5 is ranged in 100-10-2.Niobium partition decreases with the increase of[Si]% and CaO/SiO2. When α[0] and ΣFeO decrease, niobium partition decreases too. The δNb2o5 and the ratio of γsiO2 to γNb2O5 decrease with the incre-ase of slag basicity. The suitable thermodynamic conditions in direct alloying of steel with Nb2O5-bearing slag have been found

is a vector equation that relates the magnitude and direction of the force vector, to the magnitude and direction of the acceleration vector. In the previous lecture we derived expressions for the acceleration vector expressed in cartesian coordinates. This expressions can now be used in Newton's second law, to produce the equations of motion expressed in cartesian coordinates

The Baotou Iron Ore of China contains very high niobium. This paper reported the results through laboratory and practical experiments on niobium enrichment in blast furnace. The effect of temperature, constituents of slag and silicon content in hot metal on niobium recovery was studied and the results had been verified by blast furnace operation. According to the reaserch, a comprehensive extraction process that extraction combines with ore dressing and with pyro--hydro-metallurgy should be adopted for Baotou niobium resource which is difficult to concentrating. The methods of increase in niobium recovey were also suggested in this paper

采用同时平衡和质量守恒原理对全液相常温常压法制备CuInSe2(CIS)粉体过程中Cu+-In3+-Se2--NH3-L2--Cl--H2O体系的热力学平衡进行分析,并绘制一系列的浓度对数lgc-pH值曲线.依据平衡图,发现溶液中[NH3]T的变化主要影响溶液中[Cu+]T在体系中的浓度变化,[L2-]T的变化主要影响的是体系中[In3+]T的浓度变化,而[Cl-]T的变化对[Cu+]T和[In3+]T的浓度变化均有影响,并可发现在pH7.0~8.5时沉淀率最高.依据Cu+-In3+-Se2--NH3-L2--Cl--H2O体系的同时平衡和质量守恒原理,采用全液相常温常压法,在pH7.0~8.5条件下制备出粒径在20~50nm且基本符合标准化学计量比的CIS纳米粉体

In this course we will study Classical Mechanics. Particle motion in Classical Mechanics is governed by Newton's laws and is sometimes referred to as Newtonian Mechanics. These laws are empirical in that they combine observations from nature and some intuitive concepts. Newton's laws of motion are not self evident. For instance, in Aristotelian mechanics before Newton, force was thought to be required in order

§ 1. Introduction § 2. Digestion in the mouth & esophagus § 3. Digestion in the stomach § 4. Digestion in the intestine § 5. Digestion in the colon § 6. Absorption in the small intestine

bribery in international commercial transactions Aspects of corruption: its roots and consequences Several questions arise in connection with the increased interest in action against corruption at both the national and international levels. In such interest due to the higher occurrence of corrupt practices, higher detection rates or lower levels of (public, official and business)