燃气不换向蓄热式熔铝炉

蓄热式熔铝炉是一项先进节能技术，但至今在铝行业普及率不高，主要是一次性投资较大，维修费用较高。新近开发的燃气不换向蓄热式烧嘴，设备投资少、系统简化、设备故障少，使用安全可靠。     

啮合型同向旋转双螺杆挤出螺槽非充满的熔融理论研究 Ⅱ.模型的求解

根据啮合型同向旋转双螺杆挤出非充满熔融的理论模型，对描述非充满熔融过程的主要物理量：固相高度变化函数、熔融速率及熔融区总长等进行了计算分析，并对有关影响因素进行了讨论。     

应用焊道长度控制线能量

运用ＨｅｒｂｓｔＦＷ公式原理对国产碱性条件进行了大量试验，建立了焊接线能量（Ｅ），焊条熔化长度（ｌＥ），焊道长度（ｌＲ）的关系式：Ｅ＝８０８Ｄ１．８ｌＥ／ｌＲ。并应用线算图和ＳＨ－ＣＣＴ图对该式施焊结果验证，热影响区的金相组织，硬度基本一致。因此，可以应用焊道长度校核与控制线能量。     

共晶强制性熔化的界面形态

对透明共晶系ＣＢｒ４－８．４ｗｔ－％Ｃ２Ｃ１６生长的典型层片共晶组织强制熔化进行实时实地观测．表明相对于强制生长时的“界面滞后”现象，熔化界面温度高于静止时界面温度，熔化界面比静止界面更靠近热端，称为“界面超前”．随熔化速度增大，“界面超前量”增大；共晶组织分层熔化，出现两个熔化界面，α和β相熔化秩序不同，α，β相分别单独熔化，两熔化界面的相对位置由α，β相成分，熔化速度和共晶相间距等因素决定．     

Electrical conductivity,self-diffusion,and volume expansion of alkali halides at the melting point

In an earlier paper, Heisenberg's uncertainty principle was invoked at the melting point T _m of crystalline solids to provide fundamental justification for Lindemann's melting law and to compute diffusion coefficients of several alkali halides. The uncertainty principle defines breakdown of Debye zone boundary (ZB) phonons as valid collective excitations when phonon energies and line widths due to anharmonicity become comparable at T _m. Upon breakdown, random, high-frequency single-particle motion or partial decoupling of crystal ions sets in. Lifetimes of these single-particle ZB motions are determined from the minimum-uncertainty product inequality by assuming that it becomes an equality at T _m for ZB phonons. The present paper addresses improved formulation of that work and extended application to ionic electrical conductivities of 18 molten alkali halides at T _m. It is shown that use of the Debye model produces an approximate lower bound to the mean free time, not the unconstrained direct estimate previouslu implied. This feature is generally reflected in results for ionic conductivities and alkali halide diffusion coefficients for which comparison experimental data were found. However, in spite of this lower-bound formulation and the simple nature of the computation, the results compare favorably with experiment. A model of random single-particle harmonic motion superimposed on the lower-frequency collective motion is proposed to account for volume expansion accompanying the partial decoupling for hard-sphere ions. Experimental comparisons for 15 alkali halides show the decoupling volume change to account largely for the total volume change of melting (in the hard-sphere approximation), yielding a closer agreement with experiment than recent calculations aimed explicitly at the total volume change.Paper presented at the Tenth Symposium on Thermophysical Properties, June 20–23, 1988, Gaithersburg, Maryland, U.S.A.     

High-temperature properties of the Bi-Sr-Ca-Cu-O system: Simultaneous occurrence of melting, oxygen desorption, and a metal-insulator transition

We have investigated the temperature dependence of the electrical transport and the thermogravimetric properties, from -200°C to +1000, of the Bi-Sr-Ca-Cu-O high-temperature superconductor. We conclude that this system has a cooperative, simultaneous-melting/oxygen desorption/metal-insulator transition that occurs near 900°C. We speculate on its nature and on its relationship to phenomena found in other high-T _c superconductors.     

Measurement of the heat of fusion of titanium and a titanium alloy (90Ti-6Al-4V) by a microsecond-resolution transient technique

A microsecond-resolution pulse heating technique was used for the measurement of the heat of fusion of titanium and a titanium alloy (90Ti-6Al-4V). The method is based on rapid (50- to 100-s) resistive self-heating of the specimen by a high-current pulse from a capacitor discharge system and measuring, as functions of time, current through the specimen, voltage across the specimen, and radiance of the specimen. Melting of the specimen is manifested by a plateau in the measured radiance. The time integral of the net power absorbed by the specimen during melting yields the heat of fusion. The values obtained for heat of fusion were 272 J · g^–1 (13.0 kJ · mol^–1) for titanium and 286 J · g^–1 for the alloy 90Ti-6Al-4V, with an estimated maximum uncertainty of ±6% in each value.Paper presented at the Second Workshop on Subsecond Thermophysics, September 20–21, 1990, Torino, Italy.     

STUDY ON THE VARIATION MECHANISM OF CARBON CONTENT OF LIQUID IRON IN MELTING GASIFIER

This paper studied the changing principles of carbon content in direct reduction iron (DRI) and liquid iron in the COREX melting gasifier. Under the normal working conditions of experimental equipment, liquid nitrogen was poured into the melting gasifier from its tuyere to cool down quickly. And then seven cross sections were made to study the carburization reaction and its characteristics of the solid iron and the liquid iron, and also the reaction of carbon between the slag and the metal. According to the results, the influences of the thickness of the semi-coke layer and the temperature on the carbon content of liquid iron in the COREX melting gasifier were confirmed.     

一种基于架空线路CPS监测系统的融冰技术研究

我国大部分地区普遍都有冬季架空线路结冰的现象,造成大型线路结冰事故,给电力部门安全稳定运行带来极大的挑战。人工除冰或短路除冰都会使地区大面积停电,给电力系统带来损失。提出了一种基于架空线路CPS监测系统的融冰方法,当CPS监测系统检测到线路有结冰现象时,启动发热电阻线路进行加热,可以在短时间内对结冰线路进行融冰,在不停电的情况下,保障了电力安全,极大地减少了电力系统的损失。     

Effects of surfactant and particle size on the microstructure and strength of Si3N4 foams with high porosity

The highly porous Si₃N₄ ceramic foams were prepared by direct foaming with mixed surfactants. The surface tension and viscosity of slurries were tailored by different carbon chain length of surfactants and different mean Si₃N₄ particle size to achieve the pore size controlling. The nearly linear relationship between the pore size and the ratio of surface tension to viscosity was observed, which indicates that the pore size could be precisely tailored by the slurry properties. Si₃N₄ ceramic foams with porosity of nearly 94%, mean pore size of 110–230 µm, and compressive strength of 1.24–3.51 MPa were obtained.