Advanced Materials Research Vols. 129-131

Abstract: We build out a very vivid and real conditions environment based on the virtual reality of a simulation computer technology, so that users can be in a virtual environment through the man-machine interface with a virtual environment direct interaction. This paper studies 3d virtual model development and integration including the system design to realize the functions and systems integration. In its implementation, we use the model tool, 3 D R C to structure three-dimensional model, and the model tool, and finally we use virtools tool to achieve a three-dimensional with the establishment of virtual scene model. Virtual reality (virtual reality, VR) is a computer senior man-machine interface on the basic feature of absorbion, interactiveness and constructiveness [1,2]. Specifically, virtual reality is a computer that creates the stereoscopic spaces, and users can interact space objects in the interaction and watch the operation of some part of the objects in space, and freely move with the users' will so that a sense of integration and participation are produced[3,4]. It is used in computer technology at the core of modern high technology ,which means to build a realistic view, hear and touch the integration of a virtual environment with the necessary equipment and a virtual environment of the interaction and mutual influence, which results in the "immersion" be true of the environment and feel[5-7]. VR technology is computer technology, computer graphics, computer simulations visual and technical, visual physiology, psychology, the microelectronics visual display technique, solid technology, sensing to measure the technical, technological, information technology, and voice recognition software engineering and technology, integrated man-machine the skill interfacing, and network technology and artificial intelligence technology and the achievement of other high technology. Since the birth of a virtual reality technology, it has the huge economy, military and the internet, multimedia minded race in many areas in the application of technology in the 21st century as the three-big technologies.

Abstract: As the motivation and basic guarantee tool for carrying out research study in the universities, research-based learning support system is playing an important role. Aiming at the real situation and study features of the students in modern universities and combining with the research study theory, a research-based learning support system is designed based on the Study Resource Support. The core of the system is Learning Activity Support, and the key of the system is Study Guide.

Abstract: In the crystal growth process, the temperature distribution and concentration distribution at the solid-liquid interface edge are always the hot problems. In this paper, we study the concentration distribution at the solid-liquid interface edge under the natural convection conditions, we find that the concentration field is oscillating exponential decline or rose along the crystal growth direction. We also study the dendrite morphology of Al-La alloys using the experimental method, the results show that the microstructure of Al-35%La alloys is different from the common microstructure of hypereutectic alloy during the conventional casting process, the first crystalline phase is Al11La3, which composition is discontinuous along the growth direction, the main dendrite is composed of α-Al alternating with Al11La3, the results of SEM and XRD show that the chemical composition along the main dendrite exhibits periodic behavior, therefore, this microstructure is named as periodic diphase dendrite structure.

Abstract: During the individual escape, free ascent is the only way to decompression. While the men are situated in the deep pressure, the velocity of ascent, the time of getting to balance become the most important factors for escape. The paper use mathematical methods, consult the hydrodynamics parameter which educed by experiment, simulate the ascent rule while the men are in the individual escape suit, and calculate the ascent velocity, acceleration, balance time of different weight, and compare the simulation result with the experiment , which can prove the veracity of simulation.

Abstract: By analyzing and comparing several possible proposals of structure for transmission device of pipe thread shaping machine, the non-axis 2-class gear transmission device is designed innovatively, and the tube clamping device is also designed by using principle of differential screw. At last, a portable thread pipe shaping machine is designed and manufactured, which can process both linear and non-linear round pipe threads. The whole machine, with small number of parts, is compacter, smaller and lighter so that it is easier to be moved.

Abstract: This study presents heat transfer rate and temperature distributions for the prediction of each component in an air-cooled motorcycle engines. The 3-D finite element method was used to solve the temperature field and heat transfer rate for each component (intake valves, exhaust valves, piston, piston rings, cylinder head and cylinder) of motorcycle engine when the piston is in TDC and BDC. The results shows that the fractions of heat transfer rate for each component are as follows: intake valves 11％, exhaust valves 8％, cylinder head 21％, the piston 35％ and the cylinder 25％. And the temperature measurement value is in good agreement with experimental data within 20%.

Abstract: Accurate description of the material flow stress behaviour is an essential requirement for FEM simulation of metal forming processes. In the present hot compression tests of AZ80 magnesium alloy were performed on Gleeble 3500 at strain rates between 0.01-50s-1 and deformation temperatures between 300-450°C to determine the flow stress data of the AZ80 magnesium alloy. It was noticed that with increasing strain rate, deformation heating become more pronounced since there is no time for heat escaping during hot compression tests. Thus, a flow stress correction for deformation heating at high strain rates was carried out for the calculation of the constants of constitutive equation. Validation tests were then performed. Good agreements between the predicted and measured values in extrusion pressure were achieved.

Abstract: Pyramid shaped pyrolysis flame is a new method for carbon nanotubes (CNTs) synthesis. Oxy-acetylene flame was used as the source of heat, CO as the source of carbon, iron pentacarbonyl (Fe(CO)5) as the source of catalyst precursor. Field emission scanning electron microscope(FE-SEM), High resolution transmission electron microscopy (HR-TEM) and Raman spectra were used to illustrate the results of experimental. In this experimental, coating substrate is not a special process, but a part of sampling. In the first 60s of sampling time, there were not CNTs synthesis, only the phase that substrate coats particles and temperature rise, so in this phase, catalyst particles formed. 304 stainless steel plate, monocrystalline silicon chip, and brass plate were used as substrates to synthesize CNTs. 304 stainless steel plate could gain straight, long, and uniform CNTs, monocrystalline silicon chip gain curly and short CNTS, while brass gain nothing but particles. Although single-walled carbon nanotubes (SWNTs) were not observed by SEM and TEM, it was successfully done by Raman spectra, in spite of the yield was small.

Abstract: As the interface problem of discontinuity boundary condition between the oil film and the pad in thrust bearing, a conjugated solution method by using the temperature continuity and the heat flux continue is proposed. The three-dimensional calculated model of thrust bearing is constructed and solved by using finite difference method. Comparing with 2D model, the characteristics of the lubrication performance of 3D model are more different. The results show that the three-dimensional calculated model not only revealed the relation of temperature variation between the oil film layer and the pad in axial direction, but also exactly reflected real temperature distribution in the pad surface. In the same oil feed temperature condition, the minimum film thickness is 63.8μm and the maximum temperature on the pad surface reached 55°C for 3D mode, 72.6μm and 60°C for 2D mode.

Abstract: Pyramid shaped pyrolysis flame is a new method for carbon nanotubes synthesis. Oxy-acetylene flame outside the frustum of pyramid shaped reactor provides the necessary high temperature environment, while carbon monoxide is used as the source of carbon, iron pentacarbonyl (Fe(CO)5) as the source of catalyst precursor in reactor. In this experimental, substrate is the platform on which carbon nanotubes produced. The locations of 304 stainless steel and 201 stainless steel as substrates stayed in flame, 304 stainless steel pretreated or not, and different thickness of red copper and brass were studied. The results of 304 stainless steel substrate at the height of 10mm are the best, comparing with others at 7mm, 5mm, and 0mm heights. Although using 201 stainless steel as substrates has the same results, the results of it are not as good as 304 stainless steel. Pretreated 304 stainless steel as substrate can gain better properties of carbon nanotubes. Different thickness of brass and red copper can not get carbon nanotubes, only copper oxide on the surface of red copper while particles on brass.