Advanced Materials Research Vol. 625

Abstract: A lot of practice had proved that the failure rate can be used as the reliability indicators of MCM (Multi-Chip Module). The lower the junction temperature of the semiconductor integrated circuit device in MCM, the lower the failure rate of components was, thus the higher the reliability of MCM. Therefore, in order to measure the junction temperature of the semiconductor components of MCM, computer simulation is needed in the stage of design，which was essential for improving the reliability of MCM’s encapsulation and even the whole electronic machine system. In this paper, we tried to thermal design the high-power heating devices-MCM of the multi-functional electronic devices. First, the cooling principles of MCM encapsulation were introduced. And then based on the design principles and precautions of MCM, we designed an MCM encapsulation for cooling analyses of ANSYS. The results of finite element analyses showed the reasonableness of the design of MCM, and combined with the different substrate materials and circuit board materials, further discusses about improved cooling capability of MCM were expressed in this paper. At last, we got the desired effect.

Abstract: CuInSe2 thin films were successfully prepared by selenization of precursor films coated on the Mo foils. The precursor films were compacted to improve surface morphology and density of CuInSe2 thin films. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The results indicate that the single-phase CuInSe2 is formed at 210 °C in selenization process and it exhibits preferred orientation along the (112) plane. The selenization temperature is above 210 °C, the selenization temperature rises to promote the crystallinity of selenized films, not to induce the occurrence of a new phase. The compact CuInSe2 film with smooth surface can be obtained by selenization of precursor films pressed with the pressure of 300 MPa.

Abstract: The most suitable diffraction angle of aluminum alloy 3003 used for stress measuring is aimed to be determined in this paper. The experiment makes a stress measurement of a loading aluminum alloy 3003 equal strength beam with the traditional electrical measuring method and the X-ray stress measurement. With the electrical measuring method as reference, the research study the measured values that acquired from the X-ray diffraction method when the diffraction angle are 142° and 156°, and then compare them with that acquired from electrical measuring method. The measurement results demonstrate that the diffraction angle at 156 ° is better than at 142 ° based on the assessment standards of the liner slope and the distribution of data. Thus the optimum diffraction angle for X-ray to measure the macroscopic stress of aluminum alloy 3003 is 156 °. In this paper，the stress caused by the load on the equal strength beam is assumed to be "residual stress" and thus the conclusion has reference values for the standardization of residual stress measurement of aluminum alloy by XRD and has theoretical guiding significance in the production practices.

Abstract: The degradation of COD and ammonia nitrogen (NH3-N) in coking wastewater was researched using the new ultrastructure biological carriers in three-phase aerobic biological fluid-bed. The results show that the optimum conditions of the new biological carriers are as follows: HRT of 20 h, neutrality skew alkaline pH (about 7.5) and dissolved oxygen (DO) of 2~5mg/L. Under the optimum conditions, the removal efficiency of COD and NH3-N can reach 82% and 87%, respectively, when the influent concentration of COD and NH3-N is about 3000 mg/L and 60mg/L. At the same time, comparison with the activated sludge process and common biological ceramisite carriers, it is found that the most excellent treatment effect and the strongest resistance to impact are obtained under the condition of the shortest HRT in this new ultrastructure biological carriers reactor, and the effluent of two-stage reactors in series can reach the first national discharge standard, which will has a wide application prospect.

Abstract: A series of CrTiN films were successfully deposited by medium frequency magnetron sputtering in a mixture gas of nitrogen and argon. X-ray diffraction analysis shows that the CrTiN have preferential orientation of (200). The films show low friction and low wear rate at a certain percentage of the Ti content.

Abstract: Four series of cermets with the SiC whisker content between 0 and 1.0 wt.% were prepared by vacuum sintering. The transverse rupture strength (TRS), hardness (HRA) and fracture toughness (K_IC) were also measured. The SiC whisker addition was located at the grain boundaries, which prevented grain boundary migration and restrained the grain growth. However, an increasing SiC whisker content decreased the wettability of the binder on the Mo₂FeB₂ hard phase. The highest TRS and fracture toughness was found for the cermets with 0.5 wt.% SiC whisker addition, whereas the cermets without SiC whisker addition exhibited the maximum hardness.

Abstract: In this paper, the abio-superconductor heat pipe is used as heat transfer tube of all-glass of evacuated tubular solar collectors. Based on thermal analysis, the overall heat loss coefficient , the efficiency factor and the heat removal factor of superconductor heat pipe evacuated tubular collector are presented. They were compared with instantaneous efficiency between theory value of example and measure value of experiment. As a result, their opposite error less than 5.3%, it explained related calculation expression that it reflected preferably transmit heat function and characteristics of vacuum tube solar collector .It discussed how to prove collector performance and used for that type of vacuum tube of the design and the performance forecast. The heat pipe catheter contains a small amount of powder of the working medium, these media consists of a variety of inorganic elements. The properties of pipe materials can be in a very short time to achieve isothermal heat transfer, as its radial heat transfer capacity of 44 kW/m2, axial heat transfer capacity is 8600 kW/m2,heat pipe can transfer more compared with the normal.

Abstract: For the research on elastic-plastic deformation characteristics of the echelle grating in the mechanical ruling depth range, a series of nanoindentation tests are completed about the deposited Al film of available echelle grating with a Berkovich indenter on a CSM nanoindentation instrument. Then a finite element analysis of the nanoindentation process is studied with an orthogonal experiment method for a series of given parameters containing the yield stress and strain-hardening exponent. The optimum combinations of yield stress and strain-hardening exponent are 200MPa and 0.1, which are got by the objective of the least absolute value of maximum loads deviation between the indentation test and the finite element analysis. Finally the elastic-plastic stress-strain curve of power function of the Al film is represented with the difference analysis from the orthogonal simulations.

Abstract: The generalized thermoelastic diffusion problem with temperature-dependent properties is investigated in the context of the theory of generalized thermoelastic diffusion. The problem is solved by means of finite element method and the derived finite element equations are solved directly in time domain. The effects of diffusion and temperature-dependent properties on generalized thermoelastic wave and mass diffusion wave are studied in detail. The results show that all the considered variables have a non-zero value only in a bounded region and vanish identically beyond this region, the temperature-dependent properties act to reduce all the considered variables and the diffusion barely influences the considered variables.

Abstract: Ti/Cu-8Ag/S20C composite were processed by High Press Torsioning(HPT) and the effect of post-HPT heat treatment on the interfacial reaction products and the mechanical performance were studied. Intremetallic compound layer with the thickness of 11 μm was observed at the interface between Ti and Cu-8Ag for the clad heat-treated at 600°Cfor 24hrs. On the other hand, no intermetallic compounds were observed at the Cu-8Ag/S20C interface. No cracks were observed to be emanated from the corner of the indentation mark on the intremetallic compound layer at the Ti/Cu-8Ag interface, suggesting those intermetallic compounds is not so brittle. The stress-strain curves exhibited two steps in as-HPTed clad samples and those heat-treated at 600°C for 24hrs. The careful examination of the fractured plates revealed that S20C plate fractured first and then Ti and Cu-8Ag layers fractured together, suggesting the bonding strength between two layers is fairly high in the presence of intermetallic layer between Ti and Cu-8Ag layers