Papers by Author: Jing Sun

Abstract: As the most common medical apparatuses, the scalpels are extensively used for tissue cutting. During the tissue cutting process, blood adhesion to the surface of the ordinary scalpel is unavoidable and seriously affects the usability of the scalpel, which may cause medical accidents. Therefore, developing an anti-blood scalpel is of great importance. Herein, we prepare a scalpel with outstanding anti-blood property through coating method. The cleaned ordinary scalpel is immersed in the mixed solution containing nanocomposite ceramic coatings and silicone oil. After drying, the anti-blood scalpel is obtained. It can be observed from the scanning electron microscope (SEM) images that the surface of the anti-blood scalpel possesses microstructures. Compared with the ordinary scalpel, our anti-blood scalpel demonstrates outstanding blood repellence. Blood droplets can easily slide on the anti-blood scalpel surface with ~5° sliding angle. Compared with the existing scalpels with anti-blood property, our scalpel has the ceramic slippery surface rather than the slippery liquid-infused porous surfaces (SLIPSs). The stability of the ceramic slippery surface is much better than the SLIPSs because the SLIPSs are vulnerable under high temperatures and the decomposition products possess poor biocompatibility, which are harmful to human health. Therefore, the anti-blood scalpel has great application prospects in medical treatment.

Abstract: Electric hot machining (EHM) can improve the cutting performance by heating resistance, consisting of metal resistance and constriction resistance, which softens the material in the deformation zone. In this paper, we present the 3D model for heating resistance and analyze its variance with experimental verification. The results show that 3D model for heating resistance can describe heating resistance well in EHM under this experiments condition.

Abstract: A theoretical analysis was carried out to investigate the characteristics of plasma arc injected transverse to a transverse-alternating magnetic field. Two mathematical models were developed to describe both the oscillating amplitude of the plasma arc root and the heat flux density distribution of plasma arc on the workpiece surface. The characteristic of plasma arc under the external transverse-alternating magnetic field imposed perpendicular to the plasma current was discussed. The effect of processing parameters, such as working gas flux, arc current, magnetic flux density and the standoff from the nozzle to the workpiece, on the oscillation and heat flux distribution of plasma arc were also analyzed. The results show that it is feasible to adjust the shape and heat flux density of the plasma arc by the transverse alternating magnetic field, which expands the region of plasma arc thermal treatment and uniforms the heat flux density upon the workpiece. Furthermore, the oscillating amplitude of plasma arc decreases, and the heat flux density gradient upon the workpiece increases with decrease of the magnetic flux density. Under the same magnetic flux density, more gas flux and more arc current cause the oscillating amplitude to decrease. The researches have provided a deeper understanding of adjusting of plasma arc characteristics.

Abstract: All countries of the world carry forward progress in engineering education reform actively to meet the keen demand of innovative engineering talents which results from the global industry development, the source from which the global engineering excellence research project stems. Firstly, this paper reviews the origin and prophase research results of exemplary engineering innovators (EEI) research project. Secondly, this paper provides a systematic and comprehensive introduction to the industry-oriented EEI cultivation mode for bachelor’s degree engineering practiced in Mechanical Design & Manufacturing and its Automation of Dalian University of Technology based on an analysis of the cultivation actuality of EEI. Finally, this paper puts forward advices to form EEI cultivation mode with Chinese characteristics.

Abstract: Dry electrostatic cooling (DESC) assisted machining is one of the green machining technologies that uses ionized air flow as lubricating and cooling medium in the machining process. The influence of discharge parameters on the efficiency of ion transport and ozone concentration in the DESC is experimentally researched. The results show that the efficiency of ion transport increases with the rising of the discharge current and air pressure, but decreases with the rising of the distance from the nozzle and the nozzle diameter. The tungsten electrode is used to obtain high ozone concentration with the nozzle diameter of 2-4mm, air pressure of 0.2-0.4MPa, and the distance from the nozzle within 0.5mm. Experimental research on the DESC assisted machining for hardened steel GCr15 shows that cutting force decreases by 7%-28%, tool wear reduces by 30-50%, and tool life is 1.5-3.3 times more than dry cutting. Better results are achieved when increasing the cutting speed.

Abstract: The image collecting devices, which consist of optical lens, neutral density filter, narrow-band interference filter, CCD and the other equipments are set up to collect the images of plasma arc column with and without external transverse alternating magnetic field (ETAMF). On the basis of de-noising and enhancing morphological characteristics to the collected images, the characteristics of plasma arc with and without ETAMF are analyzed comparatively. The results show that the application of ETAMF is capable to get oscillation of plasma arc, and change its location, shape and heat flux density distribution, which can get efficiently control in the width of heated area and flatten heat flux density of workpiece surface.