During the laser-assited endoscopic surgery, the laser light is delivered to the deep tissue or the internal organ using a light transmitting delivery system. It is necessary to modify the direction of the light emission at the distal end of fiber tip for some application of in laser-assisted surgery. The homemade diffusing fiber and the forward firing fiber are used for the endoscopic delivery system of the continuous IR laser into the water rich tissue. The beam emission and the laser-assisted ablation and coagulation pattern were compared for two distinctive fiber systems. The diffusing fiber produced cavity and coagulation zone more or less a circular shape, while the forward fiber produced an elongated cavity and coagulation region. The diffusing fiber produced wider and shorter coagulation and cavity zone compared to that of forward-firing fiber
The multi-direction firing of the optical fiber has been required to induce wider damage zone during the laser-assisted surgery. The optical fibers tend to have poor machinability because of its hardness and brittleness. In this study, we employed the ECDM to fabricate the tip of the optical fiber in cone-shape. The con-shaped tip made the multidirectional emission of the light at the distal end of the fiber. The result showed that the lower electrolyte concentration enhanced the surface quality. The optimal concentration of electrolyte was 15% to make high quality surface of optical fiber tip in this experimental condition. When the voltage was more lower, surface quality had been become better. The suitable voltage was 30V for the effective process time.
This study was analyzed the characteristics of temperature distribution in DPF(Diesel Particulate Filter) equipped with partitioned electric heaters. Analysis parameters was used by variation to the length of pipe from exhaust manifold to inlet of filter. The temperature of the exhaust gas flowing into the DPF is related closely to the regeneration of filter. Due to space constraints, the DPF have inlet of bent pipe. The inlet of bent pipe induce the heterogeneous distribution of flow. The heterogeneous trapping of smoke is induced according to the heterogeneous distribution of flow. And the heterogeneous distribution of temperature in DPF is induced. In this study, without the use of assistive devices for even distribution of flow into DPF, the characteristics of temperature distribution in DPF were investigated according to the variation of the length of inlet pipe.
Welding and manufacturing process of pipelines is mainly organized with root-pass welding and fill-pass welding. Of them, root-pass welding is very difficult to automatize, compared to normal welding, and it doesn't guarantee high welding quality. Root-pass welding quality can be represented by back-bead width and back-bead height, and there are a variety of studies to predict back-bead geometry, currently. In this study, a variety of welding experiments were carried out to optimize root-pass welding process using GMA process. Based on the experimental results, optimal welding conditions were selected after analyzing correlation between welding parameters and back-bead geometry. Then, effectiveness of empirical models developed was compared and analyzed, and optimized empirical models were finally developed for predicting back-bead by analyzing the main effect of each factor which affects back-bead geometry and their influence on interaction.
It is important to increase the sound proof performance of building for reduction the influence of aircraft noise on the basic of actual survey of existed buildings. The purpose of this study is to propose the sound proof method about indoor noise of a movie theater due to aircraft. In this study, field measurement of aircraft noise level difference were carried out for 5 type aircraft. As the result, aircraft noise levels showed to be 83.6∼98.3dB(A) and indoor noise level were NC-50∼NC-65 over acceptable NC-30 in a movie theater. Noise reduction effect showed to be NC-15∼NC-30 in a movie theater.
Aluminum foam as porous material in wide use has the excellent mechanical and thermal properties. As adhesive process technique is used by bonding such composites as aluminum foam, fracture toughness at adhesive joint is the main point to investigate. In this study, DCB specimens are manufactured to evaluate the strengths at adhesive joints on the basis of British industrial and ISO international standards. Four kinds of specimens are made by changing the height of the specimen and these experimental results are compared with each other. Energy release rates are also calculated at mode I. As the hight of specimen becomes higher, reaction force and energy release rates become higher. Through the correlation obtained by this study result, aluminum foam material bonded with adhesive can be applied to the real composite structure and mechanical property and fracture toughness are analyzed systematically.
This study introduces the accurate correction method of bearing position error of mobile robots using Stargazer sensor. The mobile robots require some vital functions including map building, localization, path planning, obstacle avoidance for autonomous navigation. In most cases, the localization of angular pose of a robot is essential because its result has a great effect on the performance of the other functions. We demonstrated the validity of the proposed method with the results of real experiments and applied it to the photographer robot for correct bearing position error at the moment of taking a picture.
In this study, the potential possibility of biodiesel fuel was investigated as an alternative fuel for a naturally aspirated common rail diesel engine. The smoke emission of biodiesel fuel 30 vol%(max. content) was reduced in comparison with diesel fuel, that is, it was reduced approximately 60% at 4000rpm, full load. But, power, torque and brake specific energy consumption didn't have no large differences. But, NOx emission of biodiesel fuel was increased compared with commercial diesel fuel.
This analyzed the competitive structure of heat pump by nationality, by year-on-year and by technology on patent pending thru patent information analysis and applied KISTI holding DWPI for it. Heat pump technology is expected to position at development period or at start point reaching puberty just got out development period and to be consistently developed thru patent portfolio analysis.
This is the competitive structure of the wave power is studied thru patent information analysis with using of DWPI. The competitive structure is analyzed with worldwide patent pending(resistration) by year-on-year and patent pending(resistration) by nationality and IPC patent pending(resistration) current status by nationality and with technology development change of IPC patent pending(resistration) by nationality and the present condition of yesr-on-year patent pending(resistration) of main nations.
The paper describes the results of performance tests and enthalpy drop tests for a large scale turbine of power plant. The objectives of performance test is to exactly evaluate the degradation of the steam turbine generator in order to provide plant information to help performance engineers identify problems, improve performance, and make economic decisions about scheduling maintenance and optimizing operation. To see the performance changes, thermal performance calculation modelling has developed. We can obtain the detailed performance calculation methods for turbine cycle, based on the reference of ASME PTC. And also the enthalpy drop test has been carried out. The technical and economical assessment for each turbine section is analyzed based on the result of turbine enthalpy drop test By comparing the performance changes throughout the operation period, we confirmed the performance reliabilities of the turbine and its conditions.
In this study, the effect of a load cell response time at the weighing type filling system is investigated for high-speed filling. The changes in the characteristics of the physical structure of the load cell is measured and analyzed by using Single point type load cell and Bending beam type load cell. The result has improved the load cell strain and the response time by the analysis of the stress distribution and strain
The use of LNG(Liquefied Natural Gas) in transport is a suitable option to power, large long distance trucks in areas where gas is transported as LNG because there are indigenous gas supplies and no gas network. The use of LNG in passenger cars is far less viable because on average passenger cars stand idle more often, which would give rise to high evaporative losses. Therefore, the use of LNG requires storage facilities for the cold (-162℃) liquid natural gas at the roadside refueling stations and special fuelling equipment which can handle cryogenic temperatures. This paper investigated fuel supply system of a LNG cylinder, especially adiabatic performance and heat exchanger.
When a new nuclear fuel is developed, irradiation test needs to be carried out in the research reactor to analyze the performance of the new nuclear fuel. It is necessary to attach sensors in the fuel rod and connect them with instrumentation cables to check the performance of the nuclear fuel during the burn up test in the test loop. A thermocouple is installed at the center of the fuel rod to check the centerline temperature of a fuel rod during the irradiation test. Therefore, A hole needs to be made at the center of a fuel pellet to put the thermocouple. However, it is difficult to make a small fine hole on the sintered UO2 pellet with a simple drilling machine, because the hardness and density of a sintered UO2 pellet are very high. In this study, an instrumented fuel rod mock-up was fabricated using an automated precise drilling machine. Four sintered alumina were drilled off and assembled into the zircaloy tube and a thermocouple was instrumented in the fuel rod mock-up. Sealing of an instrumented fuel rod mock-up was performed in the following two methods. It is sealing of similar metals perform by welding method, and sealing of dissimilar metals perform by swagelok method.