Applied Mechanics and Materials Vols. 246-247

Abstract: With the development of high density, multi-functions, miniaturization and multi-layer on printed circuit board (PCB) design, great challenges have been presented to the miniaturization of drilling on PCB. In order to meet the hole precision, quality and improve the performance, efficiency of mechanical drilling, further research should be done on the cutting state. Kistler high-precision micro-force platform was used in this paper to test and analyze the cutting force, investigate the general laws of micro drilling, and optimize the parameters for HANS PCB drilling machine. Thereby, to improve the efficiency and precision of the drilling, range of processing, and increasing market competitiveness.

Abstract: NC systems are generally used in electromagnetic environment, so NC system should be designed for electromagnetic anti-disturbance in order to ensure system work normally. The main task of the electromagnetic compatibility is conducted around the three elements causing disturbance, which are the electromagnetic disturbance, propagate pathway and sensitive equipment. This article discusses grounding technology and electromagnetic compatibility requirement of NC system.

Abstract: This article summarizes the development of United States, Japan and other foreign combine threshing part monitoring system. Meanwhile it analyses the research status of China from two aspects of fault diagnostic and the relationship with feed rate. Which is specifically illustrated the present researching status of the fault alarm, fault warning, troubleshooting, and the relationship be-tween feed rate and travel speed, roller torque, the drive pulley oil pressure relations. At last it con-cludes the insufficiency in the present studies and points out the direction of the strengthened re-search that is model of real-time controlling about feed rate.

Abstract: Because different manufacturers of CNC machine tool use the different NC system at present, it results the actuality that the CNC machine tool is hard to integrate and manage. This paper proposed a scheme of DNC integrated system of heterogeneous CNC Machine Tool based on OPC technology, after analyzing OPC interface and industrial Ethernet technology. Establish workshop-level experimental platform of DNC system based on Ethernet network. On this platform, establish the communication with OPC Server by using VC, realize monitoring and management to the bottom heterogeneous CNC machine tool. The example proved that the scheme was practical and effective.

Abstract: The significant particle size grading and the particle breakage of deep soils are two major characteristics of super-high dumping-site. Based on the refitted large-scale direct shear experiments, this paper studied the particle breakage and shear strength of different coarse-grained soil. The experimental results indicates a conclusion: particle breakage index is very small when upright stress is less than 400kPa .The breakage rate increases obviously with the increase of upright stress. The particle breakage index is very little when coarse-grained contents are less than 46.0% .It increases significantly when coarse-grained contents are larger than 46.0%. Hyperbolic curves can express the relationship between particle breakage index and upright stress. The experiments studied on shear strength shows that the shear stress-strain curves are micro-softening model or micro-hardening model under low upright stress. The curves are slight-softening model at higher upright stress when the coarse-grained contents are equal to 24.0%. At coarse-grained contents equal 78.0%, the shear stress-strain curves are softening model under low upright stress. The shear strength envelope expressed nonlinear under higher upright stress.

Abstract: We designed the H-shaped metamaterial which is used at terahertz frequencies, and it can suppress magnetic response and construct purely electrical resonance. The resonance behaviors and the impact of geometrical parameters of the H-shaped metamaterial were analyzed by using effective circuit model. The simulation results indicate that permittivity of H-shaped metamaterial is negative at terahertz frequencies. H-shaped metamaterial could be used widely in the design of terahertz devices due to its simple structure and easy manufacture.

Abstract: A new route for improving the thermal property of phenolic resin was described. Firstly, a soluble preceramic polymer was synthesized by condensation polymerization of zirconium oxychloride, salicyl alcohol and acetylacetone in the presence of triethylamine at room temperature. A modified phenolic resin was then obtained via blending the preceramic polymer and phenolic resin in solution. The preceramic polymer was characterized by FTIR, NMR and GPC. The thermal property of the modified phenolic resin was also investigated by TGA. It was found that the preceramic polymer was composed of Zr-O-Zr as the main chain and the ligands (salicyl alcohol and acetylacetone) as the side chain. It pyrolyzed completely at 600°C and formed ZrO2 in nitrogen atmosphere. The results of TGA indicated that 5 wt% preceramic polymer could increase the thermal decomposition temperature and the char yield of the modified phenolic resin by 18°C and 25%, respectively. Moreover, the preceramic polymer allowed the char formation from phenolic resin at relatively low temperature.

Abstract: The effects on property of Fe3Al-based alloy adding 1.0at.%Mn,5at.%Cr,0.5at.%V have been studied. Alloys were smelted in a vacuum arc furnace and heat treated in box furnace under atmosphere. The tensile property test and hardness measurement indicate that Cr and V both can improve the room temperature ductility of Fe₃Al-based alloy effectively, the effect of micro V to the ductility is correspond to the effect of 5at.%Cr, the Fe3Al alloyed by V has higher tensile strength and yield strength, the effect of 1.0 at.%Mn on the property of alloy is not obvious. The effects of various elements on Fe3Al-based alloy ductility are analyzed according to the electronegativity different of between the three atoms and Fe/Al atoms. Microstructure analysis shows that the reason of V improving the strength is the effect on solution strengthening and the second phase strengthening.

Abstract: The geometrical structures of platinum atoms adsorbed on graphene were optimized using plane wave pseudopotential method with generalized gradient approximation based upon the density functional theory. Adsorption energies of both intrinsic graphene and platinum atoms adsorbed on graphene were calculated theoretically. The results show that: Compared with the intrinsic, H2 molecules are strongly adsorbed onto the platinum atoms adsorbed on graphene with higher adsorbed energy. The difference between the highest hydrogen molecule occupied molecular orbital and the 1owest unoccupied molecular orbital is significantly reduced. Between hydrogen and other atoms, the charge transfers are apparent increased. All are help for hydrogen storage.

Abstract: This paper introduces the ammonia water power cycle and presents the cycle performance criteria such as net power output, net power energy per ton of geothermal water, heat efficiency and heat exchanger area of per net power. The cycle influencing factors such as ammonia concentration, solution circulation ratio and hot water temperature are analyzed. Results show that there is an optimum range of ammonia concentration and solution circulation ratio. The power system exploits a new way for utilizing the mid-low temperature heat resource efficiently.