• 한국추진공학회지
• /
• 제7권3호
• /
• pp.22-29
• /
• 2003

KSR-III 추진기관 공급계는 각종 배관류, 밸브류 및 이를 제어하는 제어기로 구성되어 있으며, 엔진으로 유입되는 추진제의 제어를 담당하고 있다. 이러한 공급계 시스템의 특성을 검증하고, 구성부품의 성능을 확인하기 위하여 PTA-I 수류시험을 실시하였다. PTA-I 시험설비는 엔진과 헬륨가압탱크를 제외한 공급계 전체와 지원설비로 이루어져 있다. PTA-I에서는 밸브, 제어기와 같은 단품에 대한 시스템 시험, 배관특성시험, 추진제 유량조절 시험, 배관부 압력 변동폭 및 주파수 특성 시험, 레귤레이터 성능 시험등을 수행하였다. PTA-I 시험을 통하여 구성단품에 대한 문제점을 발견하고 이를 수정보완 하였으며, 공급계 시스템의 설계 데이터와 시험데이터 비교를 통한 설계 검증을 완료하였다. PTA-I 시험의 결과는 PTA-II 및 연소시험을 수행하기 위한 시스템 구성에 적용하였다.

• Archives of Plastic Surgery
• /
• 제37권2호
• /
• pp.148-152
• /
• 2010

Purpose: In treating diabetic foot ulcers, satisfactory vascularity is an essential prerequisite. To improve vascularity, a bypass graft has long been carried out. Recently, however, percutaneous transluminal angioplasty (PTA) has also been tried since the PTA is less invasive than the bypass graft. However, publication demonstrating the improvement of vascularity after the PTA are lacking. Therefore, this study was designed to show usefulness of the PTA in treating vasculopathy of diabetic foot. Materials: and Methods This study included 30 feet of 24 ischemic diabetic foot patients. Inclusion criteria were diabetes (duration > 5 years) and a significant lower extremity ischemia, as determined by a transcutaneous oxygen pressure ($TcpO_2$) < 30 mmHg. The PTA was carried out in 61 arteries. PTA procedure was considered successful, when residual stenosis was less than 30%. The procedure was considered failed when residual stenosis was more than 50%. Residual stenosis between 30% and 50% was considered acceptable. For evaluation of PTA effect, foot $TcpO_2$ and infrared thermography were measured before and 7th day after PTA. Results: Immediately after PTA performed in 61 arteries, 58 and 3 arteries were evaluated as being successful and acceptable, respectively. Before PTA, average foot $TcpO_2$ was $12.6{\pm}8.8$ mmHg and its value was increased to $44.2{\pm}23.9$ on 7th day after PTA (p<0.01). Average skin temperature was $31.8{\pm}1.2^{\circ}C$ before PTA and it was increased to $33.5{\pm}1.1^{\circ}C$ on 7th day after PTA (p<0.01). Conclusion: PTA procedure increases tissue oxygenation of ischemic diabetic feet which do not have wound healing potential due to low tissue oxygenation, to the level of possible wound healing. In addition, PTA increases skin temperature of ischemic diabetic feet which can imply an improvement of peripheral circulation.

• Journal of Welding and Joining
• /
• 제14권2호
• /
• pp.28-35
• /
• 1996

플라즈마에 의한 표면경화법(이하 PTA 육성용접이라고 함)은 개발된 이후 필요한 변수가 너무 많아 오랫동안 폭넓게 적용이 되지 못하고 있었다. 따라서 아주 우수한 코팅 품질을 필요로 하거나 재료측면에서 다른 방법을 사용할 수 없는 경우에 만 적용이 되어왔다. 그리고 경제성보다는 안정성이 우선적으로 보장 되어야 하는 경우, 예를 들면, 핵시설물, 화학설비 또한 엔진설비와 같은 곳에 사용이 되었다. 그 러나 최근에 들어서 특별히 microprocessor와 제어기술의 적용이 적은 비용으로도 가능해지면서 새로운 장치가 개발되었고, 많은 연구에 의하여 코팅의 특성에 미치는 영향을 파악하게 되므로써 PTA 육성용접이 신뢰성이 있으며 다른 육성방법에 비해서 우수한 공정으로 자리를 잡게 되었다. 한편 PTA 육성용접은 낮은 dilution, 좁은 열 영향부 그리고 상대적으로 높은 적층율의 특성이 있어 큰 부피를 코팅하거나 중요한 부품에 적용하기에 적합하다. PTA 장치가 반자동 또는 완전 자동화되면서 상대적으로 운용이 쉬워져 이러한 적용성은 더욱 확대되고 있다. PTA 육성용접은 Table 1에서 보는 바와 같이 다른 표면 경화법에 비하여 투자비용은 많이 들더라도 그 특성에 있 어서는 우수하다고 할 수 있다.

• The Korean Journal of Pain
• /
• 제13권2호
• /
• pp.191-195
• /
• 2000

Background: Vascular occlusive event is one of the etiologies of sudden sensorineural hearing loss (SNHL). Stellate ganglion block (SGB) induces dramatic and intense vasodilatation in head and neck. Based on this principle, SGB has used as one of the treatment modalities in SNHL. This study was performed to evaluate immediate response of SGB on pure tone audiogram (PTA) in SNHL. Methods: Forty patients were studied. Each patient received daily ipsilateral SGB in paratracheal approach using 0.2% bupivacaine for 2 weeks. On first, third, and fifth day of treatment, we checked their PTA twice 1 hour before (Pre-PTA) and after (Post-PTA) SGB. Pre- and Post-PTA were compared. Several factors were analyzed as a prognostic factor of therapeutic results. Results: Eleven of 40 patients revealed decreased PTA after SGB. Degree of decreased PTA were insignificant ($2.5{\pm}1.6$ dB). Initial and final PTA results was $76.2{\pm}22.5$ and $49.8{\pm}28.3$ dB, respectively. Thirty-one of 40 patients were improved their PTA over 10 dB. The recovery was mainly influenced by the severity of initial hearing loss (P<0.001) and slightly by age (P<0.05). However, the change of PTA after SGB, time interval to receive SGB, sex, site, and number of SGB were not correlated to therapeutic outcome. Conclusions: These results suggest that vasodilatation by SGB has no immediate improvement in SNHL. Therefore, we question whether SGB is beneficial to all patients with SNHL as a therapeutic modality.

• Journal of Biosystems Engineering
• /
• 제24권6호
• /
• pp.473-478
• /
• 1999

Recently, it is necessary fir surface materials to be low cost and to keep well endurable and wear in machinery field. Since most good materials with endurance and wear are expensive, they are being studied hard to modify to surface materials with endurance and wear, which overlay with the surface membrane completely. One of them is PTA(Plasma Transferred Arc Overlaying Process) method, which gets into the spotlight. It is thought to be an optimum method, since this method of overlays properly materials with about 3∼5cm surface membrane. It is necessity for the modified materials with endurance and wear to improve within the agricultural environment. Therefore, this research was used the PTA method to endure and wear a material. This method proved to be a reliable method for overlaying the membrane on the materials of an economical agricultural machinery.

• Journal of Welding and Joining
• /
• 제24권3호
• /
• pp.49-54
• /
• 2006

The Plasma Transferred Arc (PTA) overlaying method is lately introduced as one of the most useful surface modification method of the engine component. In this paper, the characteristics of the Co-base and Ni-base super alloy overlay layers by PTA method were investigated through the metallurgical, abrasive and cavitation erosion test. Experimental results showed that the abrasive wear resistance of the Co-base Stellite 6 overlayer was the most superior and followed in order of Nimonic 80A, Inconel 625 and Inconel 718. However, the cavitation erosion characteristic of the Stellite 6 overlayer was the most inferior and it was better in order of Inconel 625, Inconel 718 and Nimonic 80A.

• 대한추나의학회지
• /
• 제5권1호
• /
• pp.135-139
• /
• 2004

Objectives : The objectives of this report is to introduce PTA. Methods : The examination of the leg length inequality gives us a useful tool for diagnosis of body imbalance. especially pelvic distortion. There are four steps in the process of the leg analysis, according to "The Standard Manual of Chuna Society (2nd ed., Seoul:KCA Press. 2001)". In the last step of the analysis, knee-flexing over $90^{\circ}$, we have often experienced a specific sign that the lower legs are attracted toward one side spontaneously. The authors call it 'Lower Leg Lateral Attraction'. This is a very significant sign that gives us which is the major part between pelvis and the upper parts over sacrum. Thus it is definded as "Pelvic Twist Analysis, PTA" by the authors. With PTA, first, you must check the side of short leg and next, check the side of lateral attraction in lower leg over-flexing. If both sides coincide with each other, then the major part you can correct first is pelvic distortion. If not, you must find another part for primary correction, instead of pelvis. Conclusions : PTA becomes a useful complement to the examination of the leg length inequality.

• Journal of Korean Neurosurgical Society
• /
• 제37권2호
• /
• pp.101-104
• /
• 2005

Objective: A persistent trigeminal artery (PTA) may be found incidentally on conventional cerebral angiography and magnetic resonance(MR) angiography. Our goal is to examine the course and relationships of the vessel to the surrounding structures. Methods: Cerebral angiography was performed in 494 patients and MRA in 880; the patients had or were suspected to have cerebrovascular disease. In the images, the incidence, origin, course, and relationships of the PTA were evaluated. Results: A PTA was found in two (0.4%) of the patients undergoing cerebral angiography and three (0.34%) receiving an MR angiography. In four patients, the PTA arose from the lateral part of the cavernous segment of the internal carotid artery, then passed caudally and around the base of the dorsum sellae. In the other patient, the PTA arose from the medial aspect of the siphon, and ascended sharply to pierce the dorsum sellae and join the basilar artery. In four cases, there was hypoplasia of a proximal basilar artery below the abnormal communication; the vessel was of increased diameter above the communication. Conclusion: Identification of a PTA with a trans-sellar course is crucial if trans-sphenoidal surgery is planned. Hypoplasia of a proximal basilar artery should not be mistaken for an acquired narrowing.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2001년도 추계학술발표대회 개요집
• /
• pp.93-95
• /
• 2001

• Journal of Welding and Joining
• /
• 제20권4호
• /
• pp.517-524
• /
• 2002

An overlaying of the seating surfaces of engine valves by OAW, GTAW or PTA weldings are common practice. The OAW method of a lower torch energy density compared to GTAW and PTA methods produces smoother deposits but the pain size at the vicinity of the interface is increased remarkably up to $30~50{\mu\textrm{m}}$ (that of base metal is about $10\mu\textrm{m}$). It's grain coarsening and the solute dilution are related to the decarburizing during OAW could be minimized by reducing the preheating temperature and by maintaining the carbide precipitates in base metal prior to welding. The formation of columnar structures and carbide precipitation zone in the vicinity of the GTAW welded interface, because of the high heat concentration, causes weakened zone on the valve seat face. The width of the reaction boundary zone is about $50\mu\textrm{m}$ for PTA and GTAW overlaying, and about $150\mu\textrm{m}$ for OAW welding. The smaller width of the reaction boundary zone is the less the solute-dilution rate. Thereby PTA welding may be recommended for overlaying of the seating surfaces.