Earticle

Recent changes in health problems as well as the health delivery system demand expanding nursing roles to improve quality care and at the same time provide cost-effective health services. Nursing leaders of the future will be expected to be excellent care givers who are well prepared as researchers and managers and administrators. The purpose of developing an ND program is to train nursing leaders for the future. The program objective are to demonstrate the role as 1) an advanced practitioner who will provide theory based practice 2) a researcher and manager The target population of the ND program is as follows : 1) Nurses with a BSN degree who are seeking to advance on the career ladder 2) Non-nursing BS, BA graduates who are seeking nursing as a second career 3) Transfer students who are mature and motived to be nursing leaders It is believed that the ND program would meet the diverse needs for potential students, for their role in nursing and the health delivery system and create a meaning and challenging position in the profession of nursing. A task force team was organized to develop the ND program and its activities are as follows; 1) Information on ND programs were collected from 3 universities and reviewed 2)An advanced education needs assessment was completed and it was found that 87.6% of the subjects responded positively about advanced degree work. 3) A tentative curriculum for an ND program was developed. It is a great challenge to develop a new program for nursing however, it is also our task and responsibility to further the development of nursing.

Hastelloy C-276 composed of Cr, Mo, and Ni is a versatile, corrosion-resistant alloy with numerous industrial applications including its use in nuclear reactors, general chemical plants, and as a superconducting base material. Of especial significance, it can be used as a thin-sheet type whereby lap-joint welding is occasionally necessary. The main welding problems for thin-sheet metals are deformation and burn-through from an excessive heat input. Laser welding can minimize these problems because it has a high energy density and low heat effect on the base material. In this study, the laser-welding characteristics of lap-joint Hastelloy C-276 sheet metal were determined. The criteria of the laser-welding variables were chosen using a heat-conduction analysis, and the optimal welding parameters were selected by experimenting with an Nd:YAG laser.

In this paper, we present research experimental results about the different thickness T-joint welding of the high power continuous wave(CW) Nd:YAG laser for the secondary battery of a vehicle. Although the conventional method used for the secondary battery is a argon TIG welding, we utilize a laser welding to improve Tungsten Inert Gas(TIG) welding's weakness. The laser, which has a couple of advantage such as aspect ratio, low Heat Affected Zone(HAZ), good welding quality and fast productivity utilized in this work is a CW Nd:YAG laser. In order to observe laser welding sections, we used a optical microscope. Through the analysis of the metallographic, hardness, aspect ratio, and heat input, we obtained the desired data in condition of 1800 W laser beam power and 1.8 m/min and 2.0 m/min laser beam travel speeds. In order to compare electric resistances of the argon TIG welding and laser welding, we made an actual battery and the electric resistance of the laser welding is reduced by 40~45% comparing with the argon TIG welding.

The FPCB is used for electronic products such as LCD display. The process of manufacturing FPCB includes a cutting process, in which each single FPCB is cut and separated from the panel where a series of FPCBs are arrayed. The most-widely used cutting method is the mechanical punching, which has the problem of creating burrs and cracks. In this paper, the cutting characteristics of the FPCB have been experimented using Nd:YAG DPSS UV laser as a way of solving this problem. To maximize the industrial application of this laser cutting process, test samples of the multilayered FPCB have been chosen as it is actually needed in industry. The cutting area of the FPCB has four different types of layer structure. First, to cut the test sample, the threshold laser cut-off fluence has been found. Various combinations of laser and process parameters have been made to supply the acquired laser cut-off fluence. The cutting characteristics in terms of the variation of the parameters are analyzed. The laser and process parameters are optimized, in order to maximize the cutting speed and to reach the best quality of the cutting area. The laser system for the process automation has been also developed.

Magnesium and magnesium alloys, the lightest structural materials, have been received plenty of global attention recently. These alloys could be applied in various fields, especially the electronics industry, because of their excellent electromagnetic interference shielding. However, the welding technique of magnesium alloys has not been established. This study is related to the welding of AZ31B magnesium alloy by a short-pulsed a Nd:YAG laser. Two types of pulse waves, square pulse and variable pulse, were used to control weld defects. Results show that the crack and porosity, generated in the weld, had not been controlled by general square pulse. But through the application of variable pulse, the defects could be prevented and the good weld zone was obtained.

Q-스위칭은 셔터나 다른 광학소자를 레이저 광 공진기 내에 넣어 광이 공진기 내에서 발진하는데 손실을 유발하고, 충분한 반전분포가 활성 매질 내에서 생성되면 순간적으로 셔터를 열어 공진기 내에 축적된 에너지가 매우 강한 빛으로 방출되게 하는 것이다. 이와 같이 Q-스위칭은 레이저 공진기의 Q--factor를 감소시켰다가 갑자기 증가시키는 것이다. 레이저 Q-스위칭의 방법에는 mechanical switching 방법, electro-optic switching 방법, switching by saturable absorber 방법, acousto-optic switching 방법 등 크게 4가지가 쓰이고 있다. 이들 중 전기광학적인 효과에 의한 전기적인 전환은 짧은 펄스폭의 Q-스위칭 펄스를 생성할 수 있기 때문에 널리 사용되고 있다. 따라서, 전기광학효과의 특성을 가진 Pockel cell은 Q--switch로 사용하기 적합한 것으로 알려져 있다. 본 연구에서는 포켈스 셀 Q-스위치용 구동 장치를 스위칭 소자인 FET와 PIC 마이크로프로세서 및 펄스 트랜스로 설계, 제작하고, 펄스형 Nd:YAG 레이저 시스템에 적용하여 Q-스위치의 동작 특성을 조사, 연구하였다. 또한, 이 Q-스위치를 통하여 출력된 Nd:YAG 레이저 빔의 측정치를 이론적 계산에 의해 구해진 예상치와 비교하여 Q-스위칭 된 레이저 빔의 특성을 분석하였다.

The Q-switching the shutter or the different optical science element puts in within the laser light resonator and the storehouse departs from the within the resonator it loses the mortar and the reversal distribution which when is sufficient creates from within the active medium, opens the shutter instantaneously and it is to do to be made to emit with the light where the energy which is accumulated within the resonator is strong very. Like this Q-switching of laser resonator--It decreases factor increasing suddenly to make. To method of Laser Q-switching mechanical switching methods, electro-optic switching methods and switching by saturable absorber methods, acousto-optic switching method etc. 4 kind are being used on a large scale. In these people the conversion which is electric in compliance with the effect which is electrooptics is widely being used the Q-switching pulse of short pulse width because being it will be able to create. Consequently, Pockel cell where it has the quality of electrooptics effect) the Q-it is become known that it is suitable it uses with switch. From the research which it sees FET and one-chip microprocessor where it is a switching element and pulse transfomer to plan and produce pockel cell Q-switch driving gears, pulse style Nd: It applied in YAG Laser system and it investigated and researched the operating characteristic of the Q-switch. Also, the Q-switch leads and Nd where it is output: YAG with forecast in compliance with a theoretical calculation it comes to buy laser beam side politics it compared and laser beam qualities which had become Q-switching it analyzed.

Thd specimens were melited in high frequency induction furnace. The samples for measurements were prepared by machining cylinder of 9.5mm diameter and 15mm height. These samples were then hot-pressed according to strain rate ( .epsilon. ). These samples were decanned and cut out, and subsequently heat treated at 1000 .deg. C for 4hours. These were investigated for the change of microstructure, domain pattern, X-ray diffraction and magnetic properties. The stress distributions in the specimens during compressing process were calculated by a finite element method program(SPID). The calculated stresses were effective stress( .sigma. $_{eff}$), compressive direction stress( .sigma. $_{z}$), and shear stress( .tau. $_{rz}$ ). These stresses were compared with the experimental data.a.a.

본 연구에서 네오디뮴 (Nd)를 함유한 영구자석의 재활용 공정에 대한 Eco-efficiency 평가를 수행하였다. Eco-efficiency를 분석하기 위해 환경전과정평가 (LCA)와 전과정비용평가 (LCC)가 수행되었다. 환경적 측면에서, 1 kg의 영구자석을 재활용하기 위해서1.25E + 00 kg CO2 eq.에 해당하는 지구온난화영향을 나타내었으며, 자원고갈 측면에서는 1.10E - 02 Sb eq.에 해당하는 환경영향이도출되었다. 이 재활용을 위해서 약 2130원의 비용이 소요되었다. 순수한 Nd와 비교를 수행했을 때, 지구온난화 측면에서 6.43배의효율성이 나타나는 것으로 분석되었으며, 자원고갈 측면에서 분석하였을 때에는 5.32배의 효율성이 나타나는 것으로 분석되었다. 경제적 측면에서, 약 6.74배의 효율성이 나타났으므로, 본 재활용 공정은 환경적 및 경제적으로 모두 개선된 지속가능한 시스템이라고 분석되었다.

In this study, eco efficiency analysis is performed to analyze Neodymium (Nd) containing permanent magnet recycling process. Life cycle assessment (LCA) and life cycle costing (LCC) are used to apply eco efficiency analysis. In the environmental aspects, global warming potential (GWP) of 1kg permanent magnet is 1.25E + 00 kg CO2 eq. and abiotic resource depletion potential (ADP) is 1.10E - 02 Sb eq. This recycling process costs about 2130 KWR. Environmental efficiency of GWP is at 6.43and ADP is at 5.32 when compared with vigin metal. Economic efficiency is at 6.74. This study confirms that Nd containing permanent magnet recycling process is sustainable system because of environmental and economical improvement.

쵸크랄스키법에 의해 성장된 Nd:LLM(Nd:LiLa(MoO4)2) 단결정은 흡수스펙트럼 및 발광방출 스펙트럼 분석에 의해 레이저 다이오드 여기 마이크로칩 레이저용 모체재료 및 대용 Nd:YAG(Nd:Y3Al5O12) 레이저로서의 사용 가능성을 확인하였다. 4I9/2 4F5/2 전이 흡수대가 레이저 다이오드 여기 파장과 일치하는 809nm에서 관찰되었고, 4F3/2 4I11/2 전이에 의한 유도방출이 1.06 m 파장에서 관찰되었다. 이는 Nd:YAG 단결정의 레이저 특성과 유사하므로, 마이크로칩 레이저 및 대용 Nd:YAG 레이저로서 사용이 가능함을 확인할 수 있었다. 1.06 m 파장에서 <101> 방향으로 배향된 결정에 대한 레이저 발진시험에서 레이저 절대 및 경사효율이 각각 28% 및 38%이었고, 레이저의 최대출력은 레이저 다이오드의 약 380mW 출력에 대해 106mW이었다. <112> 방향으로 배향된 결정은 전혀 발진을 하지 못하였고, 그 이유는 적절치 못한 결정방향 때문인 것으로 사료된다.

The absorption and photoluminescence spectrum analysis was conducted to test the applicability of Nd:LLM(Nd:LiLa(MoO4)2) single crystal grown by Czochralski method as the host material for laser-diode pumped microchip laser. The absorption band of 4I9/2 4F5/2 transition was 809 nm which corresponds to the pumped wavelength of laser diode, and the stimulated emission of 4F3/2 4I11/2 transition were observed with the wavelength of 1.06 m. These results are comparable to the properties of Nd:YAG(Nd:Y3Al5O12) suggesting that Nd:LLM crystal could be used as the laser host material of diode laser and a substitution of Nd:YAG laser. The absolute and slope lasing efficiencies of the crystal oriented with <101> at the wavelength of 1.06 m measured by laser oscillation was 28% and 33%, respectively. The maximum output of microchip laser was 106 mW against 380 mW of pumped laser diode. Nevertheless, the lasing test for the crystal oriented with <112> showed no lasing due possibly to disorientation.

The Purpose of this paper is to weld a rapid palatal expander using a continuous wave Nd:YAG laser. The rapid palatal expander has become a useful treatment method for severe maxillary transverse deficiencies and posterior crossbites. Rapid maxillary expansion is a well-established method to correct transverse maxillary deficiency and arch length discrepancy. The major process parameters studied in the present laser welding experiment were the positions of focus, laser power and travel speed of laser beam. We measured the fusion zone size and its shape using an optical microscope for the observation of cross-sectional area and tension stress of a rapid palatal expander welded. Through the experimental investigation, the optimum speeds and power of laser without deficiencies of weld cross-sectional area were obtained.

Laser welding of metals has been widely used to improve a wear resistance and a corrosion resistance of the industrial parts. The objective of this research works is to investigate the influence of the process parameters, such as the welding for metals with CW Nd:YAG lasers. The bead-on-plate welding tests are carried out for several combinations of the experimental conditions. In order to quantitatively examine the characteristics of the butt welding, the welding quality of the cut section, stain-stress behavior and the hardness of the welded part are investigated. From the results of the investigation, it has been shown that the optimal welding condition without defects in the vicinity of the welded area and with a good welding quality is 1325W of the laser power, and 1.4m/min of laser welding speed.

Laser welding of dissimilar metals has been widely used to improve a wear resistance and a corrosion resistance of the industrial parts. The objective of this research is to investigate the influence of the process parameters, such as the welding for SM45C and STS304 with CW Nd:YAG lasers. The bead-on-plate welding tests are carried out for several combinations of the experimental conditions. In order to quantitatively examine the characteristics of the dissimilar welding, the welding quality of the cut section, stress-strain behavior and the hardness of the welded metal are investigated. From the results of the investigation, it has been shown that the optimal voiding condition without defects in the vicinity of the welded area and with a good welding quality is 1600W of the laser power, 0.85m/min of welding speed and $4{\ell}/min$ of pressure for shielding gas.

Dissimilar-metal welds(DHWs) are used widely in various industrial applications due to the pratical importance from the technical and economic aspect. However, DMWs have several fabricative and metallurgical drawbacks that can often lead to in-service failures. For example, the most pronounced fabrication faults are hot cracks. Recently, DMWs have used the various of heat source to decrease such as faults. In this paper, the weldability on dissimilar metal welds of Austenite stainless steel and Low carbon steel using a continuous wave Nd:YAG laser was experimentally investigated. Experiments were conducted to determine effects of welding parameters, on eliminating or reducing the extent welding zone formation at dissimilar metal welds and to optimize those parameters that have the most influence parameters such as focus length, power, beam speed, shielding gas, and wave length of laser.

Laser welding techniques have been characterised for various materials. In this paper, the laser weldability of STS304 stainless steel and Inconel 600 at dissimilar metal welds using a continuous wave Nd:YAG laser are experimentally investigated. Inconel 600 is being used in a steam generator tubing of pressurized water reactor(PWR) exposed to some corrosion. Stress corrosion cracking can occur on this material. An experimental study was conducted to determine effects of welding parameters, on eliminating or reducing the extent welding zone formation at dissimilar metal welds and to optimize those parameters that have the most influence parameters such as focus length, power, beam speed, shielding gas, and wave length of laser were tested.

In this study, wire was used as the filler material for the laser repair welding, and the phenomenon in which the supplied filler material was melted and beaded down into the specimen was examined with varying laser powers and welding speeds. The optimal processing condition was found to be the laser power of 1,300 W, the welding speed and feed wire supply speed of 0.5 ml/in and the defocused distances of +2mm. At this time, the heat input(E) was $65{\sim}75\;J/mm^2$, and no internal defect occurred. When repair welding was carried out as the optimal processing for the part that had an external defect with the radius of 2mm, the filler metal was melted, resulting in the volume smaller than the defect part and thus causing the part unfilled. Therefore, it was found to be necessary to carry out repair welding two to three times by multiple passes rather than does it only once by single pass.

Laser surface hardening technologies have been used to improve characteristics of wear and to enhance the fatigue resistance fur mold parts. The objective of this research work is to investigate the influence of the process parameters, such as power of laser and defocused spot position, on the characteristics of laser surface hardening for the case of SKD61 steel. CW Nd:YAG laser is selected as the heat source. The optical lens with the elliptical profile is designed to obtain a wide surface hardening area with a uniform hardness. From the results of the experiments, it has been shown that the maximum average hardness is approximatly 780 Hv when the power, focal position and the travel of laser are 1,095 W, 0mm and 0.3 m/min, respectively. In samples treated with lower scanning speeds, some small carbide particles appear in the interdendritic regions. This region contains fine martensite and carbide in proportions which depend on the local thermal cycle.

Laser cutting technology is one of flexible rapid manufacturing technologies with various advantageous including a high cutting speed, manufacturing of parts with a complex shape and others. The quality of the cut part and the optimum cutting conditions are highly dependent on the combination of the process parameters. The objective of this research works is to investigate the influence of process parameters, such as power of laser, cutting speed of laser and material thickness, on the surface roughness and the striation formation of the cut section for the case of cutting of CSP 1N sheet using high power Nd:YAG Laser with a continuous wave (CW). In order to find the relationship between process parameters and the surface roughness and the striation formation of the cut section, several experiments are carried out. Through the investigation of the empirical results, it has been shown that the surface roughness is highly related to the striation formation, including the frequency and angle of the striation, of the cut section. From the results of experiments, an optimum cutting speed for each cutting condition has been obtained to improve both the quality of the cut surface and the cutting efficiency.

Laser surface hardening technologies have been used to improve characteristics of wear and to enhance the fatigue resistance for automotive parts. The objective of this research work is to investigate the influence of the process parameters, such as power of laser and defocused spot position, on the characteristics of laser heat treatment for the case of SM45C medium carbon steel. CW Nd:YAG laser is selected as the heat source. The optical lens with the elliptical profile is designed to obtain a wide heat treatment area with a uniform hardness. From the results of the experiments, it has been shown that the maximum hardness is approximatly 780 Hv when the power and the travel speed of laser are 1,095 W and 0.6 m/min, respectively. In addition, the hardening width using the elliptical lens was three time larger than that using the defocusing of laser beam.

The Nd:YAG laser process is known to have high speed and deep penetration capability to become one of the most advanced welding technologies. This paper describes the machining characteristics of SM45C carbon steel welding by use of an Nd:YAG laser. In spite of its good mechanical characteristics, SM45C carbon steel has a high carbon contents and suffers a limitation in the industrial application due to the poor welding properties. The major process parameters studied in the present laser welding experiment were position of focus, travel speed and laser power. Optical microscope and SEM were used to investigate the microstructures of the welded zone. The experimental results showed that penetration depth of the welding process increases with laser power. Both the microstructural investigation and the theoretical calculations indicated that materials undergoes a very high heating and cooling cycle during welding process. It was also found that the austenite nucleation takes place at the initial stage and the completion temperature of austenite transformation is much higher than in the case of the arc welding.