Applied Mechanics and Materials Vols. 380-384

Abstract: in this paper, the author used method of Two-dimensional finite difference to establish a model of temperature in hot rolled steels in finishing stands, and used explicit difference method to solve the difference model. The model was optimized by correct parameters through particle swarm optimization combining with measure data. It has been verified that the deviation of the models prediction and real data keeps between ±10°C.

Abstract: Bi₂ (Mg_1/3Nb_2/3-xSn_x)₂O₇(BMNS)(x=0.1,x=0.15,x=0.2,x=0.25 mol) ceramics was prepared by traditional solid-state reaction method and the influence of tin ion doped amount on the dielectric properties and structure of BMNS ceramics were investigated. The results show that all of the doped samples keep a single monoclinic pyrochlore phase and there is no second phase observed. The grain size of ceramics gradually increases, the dielectric constant decreases first and then increases, the dielectric loss increases first and then decreases and the density reduces with the increase of tin ion doped amount. The density of ceramics increases first then decreases with the increase of sintering temperature. The BMNS ceramics sintered at 980 °C with 0.25 mol tin ion doping amount has a biggest density and the best properties,whose ε_r is 155(1MHz),tanδ is 0.0011(1MHz), the bulk density is 7.62 g/cm³.

Abstract: The finite-temperature magnetic properties of an antiferromagnetic (AF) bond alternating S=1/2 zigzag spin chain with asymmetrical AF next-nearest-neighbor (NNN) exchange interactions in an external magnetic field are investigated by means of the many-body Greens function theory within random phase approximation. The results show that when the NNN exchange interactions are asymmetrical, the spin system exhibit a clear ferrimagnetic ordering at finite temperatures. It is shown that the ferrimagnetic behavior is attributed to asymmetrical elementary excitations, resulting from the competition between the spin frustrations and magnetic excitations reduced by the asymmetrical NNN interactions. The mechanism of this ferrimagnetism is much different from a common one which originates from mixed spins with different spin values through antiparallel spin alignments.

Abstract: This paper studies of laser parameters for color marking on AISI 304 stainless steel by using Nd:YAG laser. Different laser parameters can affect metal color profoundly. The experiment focuses on some key parameters, and their optimum laser parameters are as follows: the vector step 0.005mm~0.010mm, the inter-step time 35μs~60μs, laser Q frequency 2KHz~4KHz, laser Q release time 10μs~20μs, scanning space 0.006mm~0.010mm. It is of significance in guiding practical application of laser color marking.

Abstract: We studied a new Heusler alloy V₂CoSi with Hg₂CuTi-type structure by first-principles calculations. The electric structure and magnetic properties have been investigated. The alloy has a total magnetic moment of 1.00μ_B per unit cell on first-principles calculations which is in agreement with the SlaterPauling (SP) rule. The magnetic moment of atom Co is 0.38μ_B and the magnetic moments of V(1) atom and V(2) atom are 0.80μ_B and-0.24μ_B respectively, so the alloy is a ferrimagnetism.

Abstract: The Heusler alloy system is a rich source of functional materials. We studied the ternary alloy Ti₂NiSb by first-principles calculations to explore for new functional alloy. We performed geometry optimization for the alloy with Hg₂CuTi-type structure and the obtained equilibrium lattice parameter is a₀=6.21 Å. The magnetic moments of atom Ni is 0.22μ_B in one cell. The alloy is a ferromagnet. The little magnetic moment of atom Ni comes from the characteristic spatial occupation of the atoms in the space structure of the alloy.

Abstract: Before casting, use filtering technology to reduce the impurities and inclusions in the melt. Whether aluminum melt processing is good or not can affect the quality of the products and then, affect the subsequent processing materials product quality. Therefore, aluminum melt filtering technology is an important part of the aluminum production technology. This paper discusses the PLC application in the aluminum melt filtration according to present situation of aluminum production..

Abstract: Based on the the effective mass approximation and variational approach, the donor impurity states confined in self-formed GaAs/Al_xGa_1-xAs quantum rings (QRs) are investigated theoretically. A uniform electric field is applied along the growth direction of the QR. The different effective masses in the different regions of the GaAs/Al_xGa_1-xAs QR are taken into consideration. Numerical results show that the binding energy of a donor impurity increases gradually, reaches a maximum value, and then decreases quickly to the special value as the QR height decreases. Given a fixed QR size, the binding energy increases for the impurity located at the center of the QR when the Al composition increases. In addition, it can also be found that when the applied electric field strength increases, the donor binding energy increases for impurities localized at the negative z axis of the QR; however, the donor binding energy decreases slightly for impurities located at the center and positive z axis of the QR.

Abstract: On the basis of brief introduction of Analytic Hierarchy Process algorithms and its research status in flow shop, a kind of AHP-based scheduling Evaluation method is proposed for semiconductor manufacturing line. An expert's experience and judgment are syncretized into hierarchy structure for making an integrated analysis and judgment towards the considered problem. An example of Intel real-world data evaluation process is used to explain this method. The result shows that the approach made the scheduling approach selection complete, scientific and precise.

Abstract: A highly osteogenic hybrid bioabsorbable scaffold was developed for bone reconstruction. Though the use of a bioabsorbable collagen and chitosan scaffold for loading velvet antler polypeptide to repair bone defect and drug treatment. Velvet antler polypeptide and collagen were extracted for developing the compounded material. The SEM results show that the collagen and chitosan scaffold maintain the natural three dimensional network structures. The cell proliferation experiment result show that the can promote the osteoblast proliferation for a long time . These results indicated that this compound scaffold can sustainable to release drug and is a good material in bone defect and drug treatment.