Advanced Materials Research Vols. 314-316

Abstract: Production of components, necessary for the construction of the machine resp. or device is a demanding manufacturing process. One of the possibilities of increasing efficiency and production quality is the introduction of unconventional technologies to the production process. Knowing the dependence of the impact of non-conventional technologies on the mechanical properties of products and their subsequent verification is an important aspect when designing and manufacturing them. The article deals with the impact of used unconventional technology, that means laser, plasma and water jet on the roughness of a cutting edge and microhardness of material S 355 J2 G3.

Abstract: Mechanical seal face texturing has the advantage of improving mechanical seal performance, such as improving opening force, reducing friction coefficient and minimizing wear and so on. In this paper, mechanical seal face, composed of sintered silicon carbon(S-SiC), is textured by the acoustic-optic Q-switched pulsed Nd:YAG laser in multi-mode. The micro-dimples are produced in mechanical seal face, and the profiles are measured by scanning electron microscopy (SEM) and 3D white light interference surface morphology apparatus. Results show that it is in the focus plane that maximal depth and minimum diameter appear and the circular profile of the micro-dimple can be acquired. And the diameter of micro-dimple increases with the increasing of single pulse energy reaching a saturation value at about 3.8mJ, but the increasing of single pulsed energy will reduce the depth of micro-dimple in a small range.

Abstract: In order to analyze the key factor to affect fatigue life of drill tools, fracture morphology and microstructure of defect samples made of 23CrNi3Mo with different types was observed by optical microscope and scanning electron microscope(SEM), and micro-hardness was tested, then failure reason was analyzed. The results show that the plastic deformation features of defect sample with high fatigue life is obvious during fatigue cracks generation and expanding, which has good ability to resist fatigue crack propagation, while impacter drill defect sample appears brittle fracture features. The surface of Atlas and impacter drill both have carburized layer with high hardness. The wide transitive layer of Atlas drill renders the strength of carburized layer and the roughness of matrix well matched and has well hardness gradient, while the impacter doesn’t. Thus the hardness gradient and the matching of strength and toughness affect the drill fatigue life heavily, and carburization and heat treatment process are very important.

Abstract: To grind fused silica in ductile mode, surface and subsurface micro cracks (SSMC) on ground fused silica should be repaired by CO2 laser irradiation before ultra-precision grinding. In this paper, 2D thermal analysis of single pass laser irradiation of fused silica was conducted, and the simulation results were discussed by comparing with the experiment results. To repair SSMC and decrease the surface roughness of ground fused silica simultaneously, the maximum temperature on the surface during laser irradiation should be controlled higher than 3280 K and lower than 3550 K.

Abstract: In laser process and laser scientific experiments it is an important research method to investigate analogy of physical parameters between the scale down models and the prototype structure by reduced-scale experiments. To the problem of the thermal-mechanical effects of the thin-walled pressure vessel irradiated by continuous wave (CW) laser, a series of approximatively geometrically scaling models with different scale-ratios are established in this paper. Laser flux and ratios of r(radius of laser spot) to R(radius of shells) keep the same for each scaling model. The similarity regularities of thermal-mechanical effects are analyzed and discussed by means of FEM numerical simulation method. The calculation results can give a guide to design for the scale down models and select for laser parameters in reduced-scale experiments.

Abstract: A new Mn-SOD gene encoding 202 amino acids was cloned from genomic DNA of Bacillus subtilis ATCC 9372 for construction of a genetic engineering bacterium to produce SOD. Its phylogenetic relationships with other Bacillus spp. revealed that this predicted protein is most closely related to B. atrophaeus NRS-213 (AY197616) and B. subtilis 168. This gene was inserted into expression plasmid pET28a and first successfully expressed in E. coli BL21. The SOD was expressed accounted for approximately 45.6% of total bacterial protein. The activity of the SOD was 2553.211 U/mg, the enzyme showed maximum activity at about pH 8.0 and relatively stable from pH 6.0 to 11.0. This SOD had a good thermal stability with >75% retaining of the relative enzymatic activity after incubation at 50 °C for 90 min. This study demonstrated that a new genetic engineering bacterium to produce SOD with high productivity has been successfully constructed.

Abstract: The plastic work temperature will increase with work piece compressing. But it is difficult to difine the coefficient of plastic work transforming into thermal energy accuraterly. In the experiment, the value of temperature rise because of plastic work could be obtained, at the experimental condition; the Conversion coeffecient of plastic work transforming into thermal energy that varys with deforming condition at the hot and high drforming rate, is usually seemed as greater than 0.95; it offers a method of determining the Conversion coeffecient of work transforming into heat and calculates it with Gleeble-3500.

Abstract: Ball screw is an important part in the machine tool feeding system. This paper researches on the ball screw, establishes the 3D virtual numerical model by Pro/engineer. Modal analysis of ball screw is carried out in three different cases by ANSYS, then gets the intrinsic frequency and vibration model of ball screw. It provides reliable reference for further structure analysis of ball screw.

Abstract: Electrospinning is kind of unique craft to fabricate nanoscale fiber in the condition of high-voltage electric field. However, due to the nanoscale diameter manufacturing, it is a challenge to get the whole manufacturing process stable at certain level. For that sake, this paper figures out the monitor method for the electrospinning equipment, which solves the former matter as well as makes the fiber generating process in control. According to the method, CCD camera is put forward to make the detection of the Taylor cone image continuously, while pattern recognition algorithm is used to real-time monitor the shape and size of Taylor cone which indicate the stable process of electrospinning. In order to get the stable Taylor cone shape, the processing result is used as feedback signal for control system of the electrospinning equipment to coordinate the feeding module or power supply module. As a result, the problem of nonuniformity and uncontrollable about electrospinning has been solved effectively; what's more, experiments testify that this method is reliable and effective.

Abstract: After a long evolution and natural selection, the creatures in the nature mostly have a graceful shape, reasonable structure and unique function. The architects have already got inspiration devised many beautiful and practical architecture from these creatures. This paper will compare some bionic architectural structure and material with the creatures in the nature to clarify a bionic structure, the principle and application of bionic material, so as to better understand the design connotation of biomimetic architecture for further development, and to provide the reference.