Applied Mechanics and Materials Vols. 275-277

Abstract: Natural gas hydrate has huge gas storage capacity, natural gas hydrate storage and transportation technology opens up a new road for energy storage and transportation industry. The current biggest technical problem is how to improve the hydrate formation rate, to increase storage capacity and form continuously. This paper analyses existing research results, and find that SDS is researched the most widely currently, but there are many insufficient. Specific effects of different surfactants on hydrate formation were summarized, hydrate formation mechanism of surfactants were expounded. The lack of research and the research direction of the future were pointed out. It is thought that further study of surfactant mechanism and build kinetics model containing surfactant have important theory value.

Abstract: Simulation study on nanowelding technology is important to improve nanowelding parameters, analyze the properties of welded structure, reveal the mechanism of nanowelding. In this paper, the progress of simulation study on nanowelding technology has been reviewed. The key and difficulties of this technology are proposed. The applications of molecular dynamics and quantum mechanics in nanowelding simulation study are introduced. Nanowelding technology is studied by molecular dynamics (MD) method, and the mechanism of ultrasonic nanowelding is revealed.

Abstract: Optical metallographic examination, scanning electron microscope as well as energy dispersive X-ray spectrometry was operated to the interface of titanium/steel laminates manufactured by explosive welding. Brittle Ti-Fe-O layer was found at the interface of titanium/steel laminates, and microcosmic crack was found perpendicular to the interface of titanium/steel laminates in the brittle Ti-Fe-O layer. The reason for the emergence of brittle Ti-Fe-O layer was analysed.

Abstract: By means of finite element method this paper analyzes a new support method used in lapping with solid abrasive and reearches lapping pressure distribution between workpiece machining surface and solid abrasive in lapping process with lapping tool pressed by three support points.From results we can find that by means of the new method the lapping pressure distribution between workpiece machining surface and solid abrasive is improved obviously in lapping process,which is favorable to increase cylindricity of machined hole.Through actual machining process, new method is demonstrated increasing cylindricity accuracy of machined holes of main cylinder significantly.

Abstract: After introducing SYZX75 wire-line coring hydro-hammer, we launched the study on its assorted drilling technology and field trial in Xiaoqinling gold ore deposit of Lingbao City of Henan Province. Field trial results showed that unit efficiency per month, average hour efficiency, roundtrip length and core recovery percentage in cracked formation could be improved obviously. We also could observe the decline of drilling cost and borehole deviation. It can be further popularized.

Abstract: For the final finishing of the substrate surface, Chemo-mechanical polishing (CMP) is often utilized. Those processes are able to offer a great sur-face roughness, but sacrifice profile accuracy. On the other hand, Chemo-mechanical grinding (CMG) is potentially emerging defect-free machining process which combines the advantages of CMP. In order to simultaneously achieve high surface quality and high profile accuracy, CMG process has been applied into machining of large size quartz glass substrates for photomask use. In this paper, based on the characteristics of higher machining efficiency and higher surface quality of ultrasonic vibration machining, a new ultrasonic vibration assisted CMG of silicon wafer hybrid technique is achieved by designing elliptical vibrator with longitudinal mode and bending mode. The experimental results show that under the elliptic ultrasonic vibration assistance, the surface roughness is decreased significantly, the surface quality is improved obviously, and moreover caused little or even doesn’t lead to the surface damage.

Abstract: Greenstone belt golden ore prospecting project at Victoria Lake in Tanzania consisted of seven boreholes and a total of 2500 meters of drilling. In fact, twelve boreholes were completed and a total of 3201.2 meters of drilling were realized. It created our record of maximum drilling meters and drilling production in five months using one drill rig. The paper introduces drilling technologies used on this district from the aspects of geographic and geological overview, drilling equipments, drilling technologies, drill bit, drilling mud and main economic indicators. It may offer guidance for drilling in similar districts.

Abstract: In this dissertation, Bi-2212 superconducting tapes was prepared by sol-gel method, in addition we mainly studied heat treatment conditions and sintering material drying conditions of the NiO/Ni substrate, and gived a optimization to the process. The heat treatment process of the NiO/Ni substrate had been researched.Based on previous experience, we explored the temperature of heat treatment and improved the process.Afterheattreatment,the samples was analyzed by metallographic microscope and X-ray diffraction,and we analysed these data. It’s concluded that the dense uniform oxide film can be sintered in 800°C with a 3 hours’ heat treatment.We further explored the conditions of the Bi-2212 superconducting materials.During the preparation. We mainly studied the drying temperature and sintering temperature ,because they would affect the gel phase transition and control components. It has a very important effect on high-quality superconducting strip preparation. Experiments results showed that drying the sample at 510 °C in temperature is best. all the samples was analyzed by X-ray diffraction. We summed up the data derived from experiments , it showed that sintering the sample at 850°C,we can obtain the mixed phase of Bi-2201 and Bi-2212.

Abstract: In-situ fabrication of TiB ceramic coating by laser cladding technology (LC) was investigated. Pulsed YAG laser with the power of 500 W was used. The mixture of Titanium powder (with the size of 20 m) and B powder (with the size of 140 m) were utilized as the precursor. The reactive transformation mechanism and phase constituents of the in-situ fabricating coating during the laser cladding process were studied by thermodynamics analysis, as well as XRD methods. Gibbs free energy theory was used to calculate the increment of Gibbs free energy at different temperature. The results show that the increment of the Gibbs free energy for the reaction equation to the in-situ fabricate TiB2 keep to be negative within the temperature of 3000K, this indicate that TiB2 can be obtained by laser cladding the mixture powder of Ti and B. XRD results show that the main phases of the coating are TiB2, TiO2 and B2O3 with relative percentage of 67.6%, 18.0% and 14.4%, respectively.

Abstract: Abstract: Acid mist suppression has always been a huge challenge, which troubled in metallurgy and metal products processing industries. According to the physical and chemical processes, the methods of acid mist suppression are discussed systematically in this paper. The application prospect of a new type of polymer microspheres used as acid mist suppressants is also presented in detail.