Nine kinds of glass-ceramic matrix composites with different compositions and interfacial strength (τs) were prepared. The influence of τs on the fracture toughness(K1c) of composites was studied. It was discoved that, for the system no chemical reaction taking place at the interface, K1c increased proportionally with τs increasing at the first stage, then decreased when τs reached a certain value. According to this result, a model of relationship between τs, thermal mismatch (Δαr) and K1c was built up. If a chemical reaction took place and a new phase was formed in the interface, the K1c of composite was effected by the combination of τs, chemical bonding, radial interfacial stress and other factors.
The microstructure of the interface of the explosively welded tantalum-steel composite which had been subjected to heat treatment at 1053 K was investigated by using optical microscopy and electron probe micro-analysis. It was confirmed that a Ta2C layer grew along the tantalum-steel interface. The carbon diffusion path at 1053 K, going through the γ-Fe, α-Fe, Ta2C and α-Ta phase regions was identified and interpreted by means of the Fe-Ta-C equilibrium phase diagram assuming that local equilibrium is established at all the phase boundaries.
Potential’s fluctuation of rust preventing oil film during its degradation was studied using wire beam electrode. Being non-destructive and simple, potential measurement is a very repetitive method. Other electrochemical testing method, e.g., polarization resistance, can breakdown the integrity of oil coating by DC current; EIS is time consuming. As a special electrochemical sensor, wire beam electrode contains 101 wires of mild steel wires, and it is helpful to improve the reproducibility of electrochemical test evidently. Using this electrode, the electrochemical parameters and their distribution which was related to underfilm corrosion process are measured directly so as to describe potential’s fluctuation of rust preventing oil film. It is pointed out that there is potential’s fluctuation on rust preventing oil film during its degradation, and this characteristic has direct effect on the self-repairing ability of rust preventing oil film. However, for the uncoated metal electrode and base oil film, there is no such behavior. It is also pointed out that inhibitors in the oil film have direct effect on its self-repairing ability.
ZnO varistors are prepared using the 0.1–0.3 mm ZnO powders. The effects of the sintering temperature, contents of In2O3 doping on the non-linear properties of ZnO varistors have been investigated. The results show that this kind of ZnO powder has a high sintering activity. It is suitable for making the low voltage varistors. The Vc decreases with the increase of sintered temperature, when the In2O3 content is fixed (0.98%, mass fraction), and increases with the increase of In2O3 contents when the temperature is steady.
The mechanism of forming defects in 2024, 7075 series aluminium alloy forgings has been studied by means of metallography, EDAX, SEM etc. The defects are divided into two types by their appearance: needle-shaped and flake-shaped. The mechanism of them forming is discussed. It has been testified that the defects result from hydrogen or oxide film. The defects can be prevented by controlling the hydrogen content in the melt and keeping oxide film from involving.
Characteristic grain size, Gc, is defined in the present paper. It indicates an intrinsic size of grain for a given system, and has the following advantages over the average grain size which is based on a statistical mean value of the linear intercept length of grains: (1) The characteristic grain size Gc has clear and determined geometric meaning, i. e. Gc refers to two times of the area-weighted average height of the surface elements to the centroid of grain or the average length of the chord through the centroid of grain; (2) The value of Gc can be directly obtained without introducing any correcting factors such as grain shape or grain size distribution factors. Generally, Gc is larger than the average grain size G when the Heyn intercept method is adopted for the grain size measurement.
The microstructures of different treated Al-5Mg-0.2Sc-0.1Zr alloys have been studied with optical microscopy and transmission electron microscope (TEM). Coherent particles with the matrix were found in as-cast sample, composite Al3Sc/Al3Zr particles were found after 13 h homogenized treatment under 470 °C. Coherent precipitates pinned dislocations and low-angle grain boundaries, and then restrained recrystallization. All kinds of particles of different treatments were not larger than 40 nm. After high-temperature stabilization treatments, most particles remain coherent with the matrix. The reasons of microstructure change at different treated conditions have been analyzed.
Because of the contents of spatial analysis were a wide range and are very complicated, there hasn’t been any unified theory system about it. In this paper, authors studied the definition and contents of spatial analysis. From the view point of the simulation of the geographical space, the authors defines spatial analysis as a system that describes the special relationship and spatial action of the objects in the geographical space. Furthermore, the contents of spatial analysis to spatial query, spatial interaction analysis and spatial decision support were extended.
A new technology for the crystallization of ammonium paratungstate with coarse grain has been studied. The factors influencing the physi-chemical properties of ammonium paratungstate crystal, such as temperature, concentration, seed crystal, agitation, etc. were examined. It is necessary to keep high temperature and low concentration in the process, and the addition of seed crystal and agitation with air is also in favor of the system. Ammonium paratungstate crystal with particle size of 36–42 µm and apparent density of 2.0–2.2 g · cm−3 were obtained by controlling suitable technological parameters.
A computer model has been developed to simulate the distribution behaviors of Ni, Co, Sn, Pb, Zn, As, Sb, Bi, Au and Ag in copper smelting process. The model assumes that the copper smelting furnace is in thermodynamic equilibrium. As many as 21 elements (Cu, S, Fe, Ni, Co, Sn, As, Sb, Bi, Pb, Zn, Au, Ag, O, N, C, H, Ca, Mg, Al, and Si) and 73 compounds are considered. This model accounts for physical entrainment in the melts. The predictions by the present computer model are compared with the known commercial data from Guixi Smelter in China. Horne Smelter in Canada and Naoshima Smelter in Japan. The agreements between the computer predictions and the commercial data are excellent, so that the present computer model can be used to monitor and optimize the actual industrial operations of copper smelting. It is applicable to simulation of almost all copper pyrometallurgical processes.
Coal and gas outbursts are a mechanical dislocation process of a gas-logged and porous medium. The existence of the disturbed coal is a precondition of the outbursts. The study showed that the disturbed coal and normal coal are greatly different in mechanical and physical properties which decided the speeds of ultrasonic wave travelling in them. This paper presents a set of experimental measuring system and method. The results of measurements conducted in 60 min areas revealed quite different ultrasonic characteristics in different types of coal mass textures. Measuring the disturbed coal is a new way for predicting the outbursts.
A new forging technique—short-hollow-rapid die forging, used in Ti-Al alloys was studied. Compared with conventional method, the new method can improve the crystalline structure properties of the forged piece, reduce the average forging pressure by 20% to 30%, lessen the thickness deviation by 5 mm, and prolong the service life of the dies by 2 to 4 times.
The synthesis and purification of modified antisense oligodeoxyribonucleotides (MAO) are desoribed. A new oligonucleotide purification method and a novel activating agent, dimethyl sulfoxide, for the condensation reaction are used. EDTA has been attached covalently to the 5′ end of the oligodeoxyribonucleotides sequence via an ethylenediamine linker in basic triethylammonium solution, then chelated with the metal ions such as Fe(II), Co(II) or Cu(II). High performance liquid chromatorgaphy is used to separate and purify this kind of MAO, using double mobile phase, triethylammonium acetate and acetonitrile. By using this routine chemical synthesis method, EDTA can be linked to the 5′ terminus of oligodeoxyribonucleotedes of any desired length and sequence, forming chimeric MAOs.
The flowing behavior of liquid slag has an important effect on the heat efficiency, recovery ratio of valuable metals and life span of the electric cleaning furnace. The velocity procedure using “k-ε” model was developed under the cylindrical coordinate system. The procedure is used to calculate the velocity field of molten slag. The forces acting on molten slag were analyzed. The calculating method of electromagnetic force was described. The discrete equations, which were solved by using SIMPLE algorithm, were generated by means of interlace grids and control volume. The boundary layers near the solid wall were treated as wall function. The velocity distribution is obtained. The results show that the velocity of molten slag varies with different horizontal sections. There are six eddies in the surface layer of molten slag. A large circle is formed in the sections below the electrodes, while the longitudinal section includes two large circles around the electrode. The influences of the features of the velocity field on the operation in the electric cleaning furnace are discussed in detail.
The effects of Mn2+ on the flotation behaviour of fine refractory antimony oxide and its flotation separation from silicified limestone were studied. The principal gangue mineral, under the condition of pH=7.5 and in the presence of modified water glass through flotability test, measurements of interfacial potential and adsorption, and X-ray diffraction technique were describled. The activation mechanism of Mn2+ in antimony oxide flotation is fully discussed via modern molecular orbit theory.
Based on the principle of statistics and the research results by Zhu Jianjun, the paper establishes the mean Cook distance of scale parameter and studies its properties. The paper still presents the robust estimate of scale parameter with minimum mean Cook distance and theoretically shows that scale parameter is not “nuisance parameter” and it determined by the plus weight squared sums of the residuals of observations. A simple numerical example is given.
Various kinds of base oils were applied to cold rolling aluminum strips on a test mill for evaluation of the influences of these base oils, aromatics contents and viscosity of base oils on their lubricating performances and surface reflectivity of rolled strips at annealing. Results showed that low friction coefficient and rolling force were obtained by using the normal paraffins, whereas their contaminations on the annealed strip surface were the same as those of other saturated hydrocarbons. Aromatics in base oil affected the surface reflectivity of annealed strips, but the decrease of aromatics in base oil was ineffective to improve rolled strips surface quality when it is less than 1%. Base oil viscosity has the great influences on the lubricating performances and surface reflectivity of annealed strips just in this condition.
A study was carried out on kinetics of oxygen evolution on lead alloy anodes in sulphuric acidic electrolyte. The influence of alloy elements Ca, Ag and Sn on the overpotential of oxygen evolution was investigated. All anodes had been subjected to a pre-polarisation before the measurement of potential-current curves for oxygen evolution. The overpotential of oxygen evolution was found to be decreased when the alloy anode contained Ca and Ag, whereas it remained unchanged when the alloy anode contained Sn. For oxygen evolution on lead alloy anodes the TAFEL equation was valid. The b vulue for Pb and Pb-Ca anodes was approx. 100, for Pb-Ag, Pb-Ag-Ca anodes it was approx. 140. The a value for Pb-Ca, Pb-Ag, Pb-Ag-Ca anodes decreased with the increase of Ca or/and Ag content. The a and b value was not influenced by Sn in the anodes.