研究了镍铬钼钢中痕量元素在真空感应熔炼过程中挥发的动力学,给出了确定挥发元素在气相边界层扩散传质系数的方法,提出了挥发元素在液/气界面挥发反应的速率常数计算公式。试验及计算结果表明,Sn、As在钢的真空感应熔炼过程中的挥发过程受液相边界层中的扩散及液/气界面挥发反应混合控制,K23值均在10-3~10-2cm/s数量级。Sn、As在液/气界面的挥发反应可能包括元素自身的挥发及其氧化物的挥发反应

Volatile organic compounds (VOCs) are liquids or solids that contain organic carbon (carbon bonded to carbon, hydrogen, nitrogen, or sulfur, but not carbonate carbon as in CaCO3 nor carbide carbon as in CaC2 or CO or CO2), which vaporize at significant rates. VOCs are probably the second-most widespread and diverse class of emissions after particulates

Ground granulated blast furnace slag (GGBFS) and steelmaking slag have been used as a raw material for cement production or as an aggregate to make concrete, which contribute aluminum, calcium, iron, and silicon oxides.The suitability of the slag for a particular application depends on its reactivity, cost, availability, and its influence on the properties of the resulting concrete.For the interest of durability studying of concrete in the presence of slag, the accelerated carbonation products and leaching behavior of the slag and Portland cement (PC) were studied.The experimental results confirmed that the slag was more resistant to carbonation compared to PC.The carbonation degree of GGBFS reduced by 17.74%;and the carbonation degrees of steelmaking slags reduced by 9.51%-11.94%.Carbonation neutralized the alkaline nature of the hydrated pastes and gave rise to the redox potential of the leachate slightly (30-77mV).The carbonation also increased the release of most of the elements pr

“Evaporation is the removal of solvent as a vapor from a solution or slurry. The vapor may or may not be recovered, depending on its value. The end product may be a solid, but the transfer of heat in the evaporator must be to a solution or a suspension of the solid in liquid if the apparatus is not to be classed as a dryer. Evaporators are similar to stills or re-boilers of distillation

must also consider heating andor cooling requirements as well as to deliver the desired head pressure to overcome hydraulic pressure drop. Operating costs must also consider equipment maintenance, cost of cleaning chemicals and labor costs

Muscles Active while Lengthening Consider the example of ordinary exercise, lets say one of the running events in the Olympics. Muscle functions to stop the motion of the athlete as often as it does to start it. When a load larger than isometric tetanus tension To is applied to a muscle in a tetanic state of activation, the muscle lengthens at a constant

(expressed as percentages of the wheat) from a well-equipped and well-adjusted mill in the U.K. yield of the individual flour streams is also shown. Flour streams with the lowest ash yield (e.g. group 1 in Table 7.1) may be described as ‘patent’ flour. Those from the end of the milling process In the milling of cereals by the gradual reduc￾machine in the break, scratch and reduction

Under appropriate cooling condition, intcrfacial phase appeared between α and β phases in Ti-5Al-2M0-3Zr alloy. Its thickness could reach 100 nm. The interfacial phase was either single layer structure or double layer structure. The monolithic layer adjacent to 3 phase was indentified as fee structure with relationship （110）β// （001）m, [11$\\mathop 1\\limits^{{\\rm{ - - }}} $]β /[110]m. The striated layer adjacent to a phase was indentified as hep with twin relationship {10$\\bar 1$1}<1$\\bar 0$12> to α. Thus, the study provided a new experimental fact for the controversial topic on structure of striated layer. Chemical composition of interfacial phase varied slightly with heat treatments, but always between that of α and β phases

The relationship among particle size, properties of heat transfer and melting rate of fluxes as well as the main factors which have effect on the prefused fluxes have been studied. Under the conditions of same components and particle size, the melting temperature of prefused fluxes is lower than that of mixed fluxes. With the decreasing of particle size, the difference of melting temperature between the two type of fluxes decreases also. The larger the particle size, the greater the melting rate of prefused type fluxes

It is shown that the average [O] in the steel can be decreased to 12.86 ppm and there is an optimal [%Si] at the end of melting as 0.11%, at which [O] after vacuum carbon deoxidation （VCD） is minimum. A kinetical model has been deduced to simulate the VCD process. The results show that adding Si before Al is superior to the adding Al before Si with respect to the final [O] in the steel. It is suggested that the melting point of covering slag should be lower than 1550℃, and （FeO+MnO） should be less than 1%, so as to effectively refine GCr15 steel