• 대한생식의학회:학술대회논문집
• /
• 대한불임학회 2006년도 The 5th Biannual Meeting of Pacific Rim Society for Fertility and Sterility
• /
• pp.174.1-174.1
• /
• 2006

• 대한금속재료학회지
• /
• 제47권11호
• /
• pp.722-727
• /
• 2009

The bipolar plates are not only the major part of the polymer electrolyte membrane fuel cell (PEMFC) stack in weight and volume, but also a significant contributor to the stack costs. Stainless steels are considered to be good candidates for bipolar plate materials of the PEMFC due to their low cost, high strength and easy machining, as well as corrosion resistance. In this paper, 316L stainless steel with and without nitrogen ion implantation were tested in simulated PEMFC environments for application as bipolar plates. The results showed that the nitride formed by nitrogen ion implantation contributed the decrease of the interfacial contact resistance without degradation of corrosion property. The combination of excellent properties indicated that nitrogen ion implanted stainless steel could be potential candidate materials as bipolar plates in PEMFC. Current efforts have focused on optimizing the condition of ion implantation.

• 한국산업보건학회지
• /
• 제34권2호
• /
• pp.125-133
• /
• 2024

Objectives: The aim of this study is to develop a comprehensive Occupational Safety and Health (OSH) guide for maintenance tasks in semiconductor processing, specifically focusing on etching, deposition, and ion implantation processes. Methods: The development of the OSH guide involved a literature review, consultations with industry experts, and field investigations. It concentrates on Maintenance Work (MW) operations in these specialized areas. Results: The result is a detailed OSH guide tailored to MW in etching, deposition, and ion implantation facilities within semiconductor processing. This guide is structured to assist maintenance workers through pre-, during and post-MW phases, ensuring easy comprehension and adherence to safety protocols. It highlights the necessity of safety and health measures throughout the MW process to protect personnel. The guide is enriched with real-life scenarios and visual aids, including cartoons and photographs, to aid in the understanding and implementation of safety and health principles. Conclusions: This OSH guide is designed to enhance the protection of workers engaged in maintenance activities in the electronics sector, particularly in semiconductor manufacturing. It aims to improve compliance with safety and health standards in these high-risk environments.

• 전자통신동향분석
• /
• 제33권6호
• /
• pp.12-23
• /
• 2018

In this paper, we review the technical trends of diamond and gallium oxide ($Ga_2O_3$) semiconductor technologies among ultra-wide bandgap semiconductor technologies for harsh environments. Diamond exhibits some of the most extreme physical properties such as a wide bandgap, high breakdown field, high electron mobility, and high thermal conductivity, yet its practical use in harsh environments has been limited owing to its scarcity, expense, and small-sized substrate. In addition, the difficulty of n-type doping through ion implantation into diamond is an obstacle to the normally-off operation of transistors. $Ga_2O_3$ also has material properties such as a wide bandgap, high breakdown field, and high working temperature superior to that of silicon, gallium arsenide, gallium nitride, silicon carbide, and so on. In addition, $Ga_2O_3$ bulk crystal growth has developed dramatically. Although the bulk growth is still relatively immature, a 2-inch substrate can already be purchased, whereas 4- and 6-inch substrates are currently under development. Owing to the rapid development of $Ga_2O_3$ bulk and epitaxy growth, device results have quickly followed. We look briefly into diamond and $Ga_2O_3$ semiconductor devices and epitaxy results that can be applied to harsh environments.

• Clinical and Experimental Reproductive Medicine
• /
• 제34권3호
• /
• pp.197-205
• /
• 2007

목 적: 본 연구에서는 과배란 유도과정에서 나타나는 고농도의 에스트라디올이 임상 결과에 미치는 영향을 알아 보기 위해, 신선주기 배아이식과 동결-응해 배아이식의 임신율, 착상률과 분만율을 살펴보았다. 연구방법: 2003년부터 2005년까지 제일병원 아이소망센터를 내원한 불임 환자에서 신선주기 배아이식 1,565주기와 동결-융해 배아이식 670주기를 대상으로 조사하였다. 과배란 유도 시 hCG투여 당일 에스트라디올 농도에 따라 일차적으로 네 그룹으로 (A: 1,000$\sim$2,000 pg/ml, B: 2,000$\sim$3,000 pg/ml, C: 3,000$\sim$4,000 pg/ml, D: 4,000 pg/ml 이상) 구분하였으며, 이차적으로 환자의 나이에 따라 35세 미만인 군과 이상인 군에서 각각의 임신율, 착상률과 분만율을 통계적으로 분석하였다. 결 과: 전체적으로 신선주기 배아이식과 동결-융해 배아이식에서의 임신율, 착상률 및 분만율에는 유의한 차이가 없었다. 그리고 35세 미만인 환자들에서도 에스트라디올 농도에 따른 각 군에서의 신선주기와 동결-응해 배아이식의 임상결과에는 차이가 없었다. 그러나 35세 이상의 환자들에서는 에스트라디올 농도가 높은 Group-D에서 동결-융해 배아이식의 임신율이 신선주기 배아이식에서보다 유의하게 높게 나타났다 (51.3% vs 25.0%, p<0.05). 결 론: 결론적으로 나이가 많은 환자에서 과배란 유도에 의해 과도하게 높아진 고농도의 에스트라디올은 자궁내막의 착상 환경과 임상 결과에 좋지 않은 영향을 줄 수 있으므로, 이러한 경우 당 주기에 이식하는 신선주기 배아이식보다는 동결-융해 배아이식을 시도하는 것이 높은 임신율을 기대할 수 있는 방법으로 사료된다.

• 한국진공학회지
• /
• 제7권s1호
• /
• pp.78-84
• /
• 1998

Niobium ions of 380 keV energy have been implanted at 300k in sapphire with a dose of $5\times10^{16}\textrm{ions/cm}^2$ and subsequently thermal annealed up to $1100^{\circ}C$ at reducing atmosphere. The behavior of the radiation damage produced by ion implantation followed by annealing is investigated using optical absorption technique and X-ray photoelectron spectroscopy(XPS). It is found that different defects annealed are dependent on the annealing temperature owing to different mechanisms which are proposed on the basis of the optical absorption measurement, and the implanted niobium in sapphire is in different local environments with different charge states after annealing, which are analyzed by XPS measurements.

• Clinical and Experimental Reproductive Medicine
• /
• 제33권4호
• /
• pp.237-243
• /
• 2006

목 적: 동결-융해 배아이식은 보조생식술에서 환자들에게 보다 많은 임신의 기회를 제공해줄 수 있는 방법으로 이용되고 있다. 본 연구에서는 예후가 좋지 않은 환자들에서 동결-융해 배아이식의 효용성을 알아보고자 하였다. 연구방법: 나이가 많은 고령 환자군 (38~44세)과 신선주기 배아이식에서 임신 실패군을 연구대상으로 하였다. 과배란 유도를 통해 채취한 난자를 일반적인 체외수정 또는 세포질내 정자주입술을 시행하여 수정을 유도하고, 잉여의 전핵 또는 난할 시기의 배아를 완만동결법으로 동결하였다. 동결보관 배아는 급속융해법으로 융해하여 호르몬요법을 시행한 환자의 자궁에 이식하였다. 신선 배아이식과 동결-융해 배아이식 과정에서의 배아 상태, 임신율, 착상률 등을 통계적인 방법으로 분석하였다. 결 과: 나이가 많은 고령군에서 신선 배아이식을 시행한 환자들과 동결-융해 배아이식을 시행한 환자들의 평균 연령은 $40.0{\pm}1.8$세 (n=206)와 $39.9{\pm}1.9$세 (n=69)로 통계적으로 유의한 차이가 없었으나, 임상적인 임신율과 착상률은 동결-융해 배아이식에서 29.0%와 11.2%로 신선 배아이식의 16.5%와 7.0%에 비해 통계적으로 유의하게 높게 나타났다. (p<0.05). 첫 번째 신선 배아이식에서 임신 실패군의 연속되는 신선 배아이식 환자군 ($31.2{\pm}2.3$, n=40)과 동결-융해 배아이식 환자군 ($31.9{\pm}3.1$, n=119)에서의 평균 연령은 차이가 없었으며, 임상적 임신율 (42.5% vs 40.3%)과 착상률 (22.6% vs 18.8%)도 유사하였다. 결 론: 본 연구에서는 동결-융해 배아이식이 고령 환자들에서 효과적으로 임신율과 착상률을 높일 수 있음을 보여주고 있다. 이러한 결과는 과배란 유도에 따른 자궁의 착상 환경 변화가 고령 환자들에서 임신율과 착상률을 저하시키는 것과 관련이 있을 것으로 생각된다.

• Safety and Health at Work
• /
• 제4권3호
• /
• pp.156-159
• /
• 2013

Background: Cardiac pacemakers are known to be susceptible to strong electromagnetic fields (EMFs). This in vivo study investigated occurrence of electromagnetic interference with pacemakers caused by common environmental sources of EMFs. Methods: Eleven volunteers with a pacemaker were exposed to EMFs produced by two mobile phone base stations, an electrically powered commuter train, and an overhead high voltage transmission lines. All the pacemakers were programmed in normal clinically selected settings with bipolar sensing and pacing configurations. Results: None of the pacemakers experienced interference in any of these exposure situations. However, often it is not clear whether or not strong EMFs exist in various work environments, and hence an individual risk assessment is needed. Conclusions: Modern pacemakers are well shielded against external EMFs, and workers with a pacemaker can most often return to their previous work after having a pacemaker implanted. However, an appropriate risk assessment is still necessary after the implantation of a pacemaker, a change of its generator, or major modification of its programming settings.

• 전자통신동향분석
• /
• 제5권1호
• /
• pp.55-70
• /
• 1990

SIMOX SOI is known to be one of the most useful technologies for fabrications of new generation ULSI devices. This paper describes the current status of SIMOX SOI technology for ULSI applications. The SIMOX wafer is vertically composed of buried oxide layer and silicon epitaxial layer on top of the silicon substrate. The buried oxide layer is used for the vertical isolation of devices The oxide layer is formed by high energy ion implantation of high dose oxygen into the silicon wafer, followed by high temperature annealing. SIMOX-based CMOS fabrication is transparent to the conventional IC processing steps without well formation. Furthermore, thin film CMOX/SIMOX can overcome the technological limitations which encountered in submicron bulk-based CMOS devices, i.e., soft-error rate, subthreshold slope, threshold voltage roll-off, and hot electron degradation can be improved. SIMOX-based bipolar devices are expected to have high density which comparable to the CMOX circuits. Radiation hardness properties of SIMOX SOI extend its application fields to space and military devices, since military ICs should be operational in radiation-hardened and harsh environments. The cost of SIMOX wafer preparation is high at present, but it is expected to reduce as volume increases. Recent studies about SIMOX SOI technology have demonstrated that the performance of the SIMOX-based submicron devices is superior to the circuits using the bulk silicon.

• Toxicological Research
• /
• 제25권4호
• /
• pp.209-216
• /
• 2009

We have recently reported that the continuous exposure of rats to a concrete building environment under cool temperatures had adverse effects on general health parameters and embryo-fetal development. This study examined to compare the potential effects of concrete and wood building environments on pregnant dams and embryo-fetal development in rats. Groups of 10 mated females were exposed to polycarbonate (control), concrete, or wood cages from gestational days (GD) 0 to 20 under cool temperatures $(11.9\sim12.3^{\circ}C)$. All the females underwent a caesarean section on GD 20, and their fetuses were examined for any morphological abnormalities. The temperatures in the cages were similar in all groups but the relative humidity in the concrete and wood groups were higher than in the control group. The concentration of volatile organic compounds in the wood group was higher than in the control group. In the concrete group, maternal effects manifested as an increase in the incidence of clinical signs, a lower body weight, and a decrease in the thymus and ovary weights. Developmental effects included increased post-implantation loss and decreased litter size. Infrared thermal analysis showed that the skin temperature of the rats in the concrete group was lower than that in the control group. In contrast, there were no exposure-related adverse effects on the maternal and developmental parameters in the wood group. Overall, the exposure of pregnant rats to a concrete building environment under cool temperatures has adverse effects on the clinical signs, body weight, skin temperature, organ weight, and embryo-fetal development. On the other hand, exposure to a wood building environment does not have any adverse effects in rats.