• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.68-69
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• 2013

금속 씨드 층(seed layer)을 직경 $10{\mu}m$, 깊이 $100{\mu}m$, 고종횡비 10:1 비아에 스퍼터링하였다. 금속 씨드 층의 두께는 스퍼터링 시간, 압력, 및 타겟파워를 변화하여 조절하였다. 금속 씨드층 스퍼터링 후 전기도금에 의해 구리 충전을 시도하였다. 비아의 고종횡비가 증가하면 비아 폭이 좁아져 비아의 하부층과 하단 측면 두께는 비아 상부 측면 두께만큼 충분하지 않아 문제가 될 수 있다. 스퍼터링 조건을 최적화 함으로써 씨드층의 특성을 높이고, 비아 홀 지름의 감소 속도를 줄일 수 있었다. 종래의 스퍼터링 방식을 이용하여 비아 입구의 opening percentage를 약 64%로 하고, 하부 씨드층 두께가 46.7 nm 인 금속 씨드층을 형성할 수 있었다. 이 씨드층 상에 전기도금으로 Cu filling을 성공적으로 할 수 있었다.

• Journal of Korea Fair Competition Federation
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• no.108
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• pp.2-4
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• 2004

원가를 공개한다면 사실상 건설사들의 가격담합을 조장하는 결과가 되고 말 것이다. 왜냐하면 서로 경쟁사의 원가구조를 알게 되고 여기에 사회적으로 허용되는 이윤율을 알면 분양가가 얼마나 될 것인지를 짐작할 수 있어 경쟁사의 가격도 알 수 있게 된다. 그렇다면 구태여 경쟁사가 자기의 가격보다 낮은 가격으로 경쟁을 할까봐 두려워서 원가를 절감하고 나아가 가격을 낮추려는 압력이 줄어들 수밖에 없을 것이다. (중략) 이처럼 원가공개는 담합의 성공요인 중의 하나인 담합위반의 감시를 매우 쉽게 해 주고 마는 셈이다. 이런 이유로 공정거래법은 경쟁사업자들 간의 가격정보 교환을 담합의 한 수단 내지 정황증거로 보고 있다. 그런데 법령으로 가격정보의 가장 중요한 부분인 원가를 공개하라는 것은 결국 담합을 조장하여 가격경쟁을 감소시키는 결과가 될 뿐일 것이다.

• Journal of the Korean Chemical Society
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• v.48 no.3
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• pp.243-248
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• 2004

Brake theory of viscosity, which can sucessfully calculate the viscosity of real gases, dense gases and liquids, is extended to the binary gas mixture. Adjustable parameters are not involved, but the calculated results are good agreements with the experimental values at high pressure as well as low pressure. Corresponding state equation for viscosity can be obtained by using the Redlich-Kwong equation, so that we hope this equation may be useful for the supercritical fluid in engineering applications at high pressure around the critcal point.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.268-271
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• 2010

Hypersonic engine test facility with ejector system was tested. Ejector system was designed by revised EJSIMP code. The performance of the ejector system was predicted by numerical analysis. As a result, ejector system satisfied the facility design requirement. Based on the pressure level, the facility was successfully started at Mach 3.5 and 20km altitude condition.

• Journal of Yeungnam Medical Science
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• v.11 no.2
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• pp.230-239
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• 1994

In Order to evaluate determinants of successful percutaneous transluminal coronary angioplasty (PTCA), PTCA was performed for 172 coronary arterial lesions in 120 patients (89 male, 31 female) at Yeungnam university hospital from Sep. 1992 to Aug. 1993. The corinary artery luminal diameter at the site of the original stenosis was eveluated from end-diastolic frames of identical projections of the preangioplasty and immediate post angioplasty. The coronary luminal and balloon diameters were measured with using of computer measuring system. Overall success rate of 172 attempted lesions was 87.2%. Success rate of female patients was 93.5% and higher than those of male patients. According to the clinical diagnosis, success rate in stable angina was 93.7% and higher than those of post myocardial infarction angina, unstable angina and acute myocardial infarcrion. Success rate of American Heart Association type C lesion was 65.5% and lower those of type A (95.7%), type B (89.5%). There was signfifcantly difference in preangioplasty luminal stenosis, elastic recoil and length of lesion between successful PTCA group and failed PTCA group. Success rate of lesion location at a bend > $45^{\circ}$ and presence of intracoronary thrombus were lower than than those of other angiographic findings. In coclusion, primary angioplasty success was affected by specific angiographic factors. Stenosis severity, thrombus, lesion location at a bend > $45^{\circ}$, elastic recoil, and length of lesion were the principle of determinants of coronary angioplasty success rate.

• Information Systems Review
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• v.17 no.1
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• pp.65-92
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• 2015

Driven by the development of information technologies, information system (IS) use has been common even in military organizations. In particular, field artillery is currently using the Battalion Tactical Commanding System-A1 (BTCS-A1) to improve fire support. The use of BTCS-A1 makes fire-commanding processes simple and autonomous, which leads to shorten time to support fire. Although BTCS-A1 has been considered as a helpful system, there still exists some dispute regarding its effectiveness and impact on task performance. By conceptualizing BTCS-A1 use as appropriation, this study investigates how BTCS-A1 appropriation promotes task performance. We also hypothesize that IS quality, organizational pressure (institutional pressure and supervisor influence), and team climate (team learning climate and team empowerment climate) increase the appropriation. Survey results show that organizational pressure and team climate promote BTCS-A1 appropriation, which improves users' task performance. However, effect of IS quality is not significant. Theoretical and practical implications are presented.

• Tuberculosis and Respiratory Diseases
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• v.46 no.3
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• pp.350-362
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• 1999

Background: Acute Respiratory failure which is developed after extubation in the weaning process from mechanical ventilation is an important cause of weaning failure. Once it was developed, endotracheal reintubation has been done for respiratory support. Noninvasive Positive Pressure Ventilation (NIPPV) has been used in the management of acute or chronic respiratory failure, as an alternative to endotracheal intubation, using via nasal or facial mask. In this study, we evaluated the usefulness of NIPPV as an alternative method of reintubation in patients who developed acute respiratory failure after extubation. Method: We retrospectively analyzed thirty one patients(eighteen males and thirteen females, mean ages $63\pm13.2$ years) who were developed acute respiratory failure within forty eight hours after extubation, or were extubated unintentionally at medical intensive care unit(MICU) of Asan Medical Center. NIPPV was applied to the patients. Ventilatory mode of NIPPV, level of ventilatory support and inspiratory oxygen concentration were adjusted according to the patient condition and results of blood gas analysis by the attending doctors at MICU. NIPPV was completely weaned when the patients maintained stable clinical condition under 8 $cmH_2O$ of pressure support level. Weaning success was defined as maintenance of stable spontaneous breathing more than forty eight hours after discontinuation of NIPPV. Respiratory rate, heart rate, arterial blood gas analysis, level of pressure support, and level of PEEP were monitored just before extubation, at thirty minutes, six hours, twenty four hours after initiation of NIPPV. They were also measured at just before weaning from NIPPV in success group, and just before reintubation in failure group. Results: NIPPV was successfully applied to thirty-one patients of thirty-two trials and one patient could not tolerated NIPPV longer than thirty minutes. Endotracheal reintubation was successfully obviated in fourteen patients (45%) among them. There was no difference in age, sex, APACHE III score on admission at MICU, duration of intubation, interval from extubation to initiation of NIPPV, baseline heart rate, respiratory rate, arterial blood gas, and $PaO_2/FiO_2$ between the success and the failure group. Heart rate and respiration rate were significantly decreased with increase $SaO_2$ after thirty minutes of NIPPV in both groups(p<0.05). However, in the patients of failure group, heart rate and respiratory rate were increased again with decrease in $SaO_2$ leading to endotracheal reintubation. The success rate of NIPPV treatment was significantly higher in the patients with COPD compared to other diseases(62% vs 39%) (p=0.007). The causes of failure were deterioration of arterial blood gas without aggravation of underlying disease(n=9), aggravation of undelying disease(n=5), mask intolerance(n=2), and retained airway secretion(n=l). Conclusion: NIPPV would be a useful therapeutic alternative which can avoid reintubation in patient who developed acute respiratory failure after extubation.

• Tuberculosis and Respiratory Diseases
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• v.44 no.3
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• pp.592-600
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• 1997

Background : The level of imposed work of breathing (WOB) is important for patient-ventilator synchrony and during weaning from mechanical ventilation. Triggering methods and the sensitivity of demand system are important determining factors of the imposed WOB. Flow triggering method is available on several modern ventilator and is believed to impose less work to a patient-triggered breath than pressure triggering method. We intended to compare the level of imposed WOB on two different methods of triggering and also at different levels of sensitivities on each triggering method (0.7 L/min vs 2.0 L/min on flow triggering ; $-1\;cmH_2O$ vs $-2cm\;H_2O$ on pressure triggering). Methods : The subjects were 12 patients ($64.8{\pm}4.2\;yrs$) on mechanical ventilation and were stable in respiratory pattern on CPAP $3\;cmH_2O$. Four different triggering sensitivities were applied at random order. For determination of imposed WOB, tracheal end pressure was measured through the monitoring lumen of Hi-Lo Jet tracheal tube (Mallincrodt, New York, USA) using pneumotachograph/pressure transducer (CP-100 pulmonary monitor, Bicore, Irvine, CA, USA). Other data of respiratory mechanics were also obtained by CP-100 pulmonary monitor. Results : The imposed WOB was decreased by 37.5% during 0.7 L/min on flow triggering compared to $-2\;cmH_2O$ on pressure triggering and also decreased by 14% during $-1\;cmH_2O$ compared to $-2\;cmH_2O$ on pressure triggering (p < 0.05 in each). The PTP(Pressure Time Product) was also decreased significantly during 0.7 L/min on flow triggering and $-1\;cmH_2O$ on pressure triggering compared to $-2\;cmH_2O$ on pressure triggering (p < 0.05 in each). The proportions of imposed WOB in total WOB were ranged from 37% to 85% and no significant changes among different methods and sensitivities. The physiologic WOB showed no significant changes among different triggering methods and sensitivities. Conclusion : To reduce the imposed WOB, flow triggering with sensitivity of 0.7 L/min would be better method than pressure triggering with sensitivity of $-2\;cm\;H_2O$.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.241-241
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• 2016

반도체 선폭이 20 nm급까지 감소함에 따라 기존에 수율에 문제를 끼치던 공정 외부 유입 입자뿐만 아니라, 공정 도중에 발생하는 수~수십 나노의 작은 입자도 수율에 악영향을 끼치게 되었다. 이에 따라 저압, 극청정 조건에서 진행되는 공정 중 발생하는 입자를 실시간으로 모니터링 할 수 있는 장비에 대한 수요가 발생하고 있다. Particle beam mass spectrometer (PBMS)는 이러한 요구사항을 만족할 수 있는 장비로 100 mtorr의 공정 조건에서 5 nm 이상의 입자의 직경별 수농도를 측정할 수 있는 장비이다. PBMS로 입자의 수농도를 측정하기 위해서는 PBMS 전단에서 입자를 중앙으로 집속할 필요가 있다. 공기역학렌즈는 PBMS 전단에서 입자를 집속시키기 위해 일반적으로 널리 사용되고 있는 장비로 여러 개의 오리피스로 이루어져 있다. 공기역학렌즈를 지나는 수송 유체와 입자는 이러한 연속 오리피스를 거치면서 팽창과 수축을 반복하며, 관성력의 차이로 인해 입자가 중앙으로 집속된다. 그러나 기존 공기역학렌즈는 고정된 직경의 오리피스를 사용하기 때문에 설계된 공정조건 이외에는 입자의 집속효율이 감소한다는 단점을 지닌다. 따라서 공정조건이 바뀔 경우 공기역학렌즈를 교체해야 되며, 진공이라는 환경하에서 이러한 교체는 많은 시간과 노력을 요구로 한다. 본 연구에서는 이러한 공기역학렌즈의 문제점을 해결하기 위해 다양한 공정조건에서 교체 없이 사용할 수 있는 새로운 형태의 직경 가변형 공기역학렌즈인 조리개형 공기역학렌즈를 제안하였다. 기존 연구를 통해 조리개형 공기 역학 렌즈가 다양한 압력 범위 내에서 나노입자를 성공적으로 집속할 수 있음을 보였지만, 장비를 상용화하기 위해서는 사용자가 좀 더 쉽게 렌즈직경을 결정 할 수 있어야 한다. 이에 본 연구에서는 조리개형 렌즈의 중공 직경에 따른 입자 집속 특성을 평가하였으며, 최종적으로 압력과 집속하고자 하는 직경에 따라 렌즈 중공 직경을 결정할 수 있게 해주는 데이터 베이스를 제작하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.3
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• pp.95-101
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• 2004

Stability rating of KSR-III rocket engine is conducted based on stability rating tests in the course of development of KSR-III rocket engine. Rocket engine is approved to have combustion stabilization ability when it can suppress the external perturbation or pressure oscillation with finite amplitude and recover the original stable combustion. Rocket engine in flight may be perturbed by unexpectedly large-amplitude pressure oscillation and thus a designer should not only assure combustion stabilization ability of the engine but also quantify the stabilization capacity. For this, principal quantitative parameters and their evaluation are introduced. To verify dynamic stability of KSR-III rocket engine, six stability rating tests have been conducted. Based on these test results, such parameters are quantified and thereby, the stabilization capacity of KSR-III rocket engine is evaluated.