N₂분위기에서 Solder 접합부의 젖음성 및 결함특성에 관한 연구

최명기,황선효,이창배,정재필,서창제 大田産業大學校 2001 한밭대학교 논문집 Vol.18 No.-

본 실험을 통하여 대기와 N_2분위기에서의 젖음력과 솔더 접합부의 결함특성에 대하여 연구 검토하였다. 모든 시편 조건에서 질소분위기에서의 젖음성이 대기 중에서 젖음성 보다 좋아졌다. 또한 N_2유량이 증가함으로서 젖음 시간은 짧아지고, 젖음력은 증가하였다. N_2분위기에서 브리지(Bridge)발생률이 25∼76%정도로 현저히 감소하였다. N_2분위기에서는 젖음력의 향상으로 솔더 접합부가 안정되었으며 결함 발생률도 현저하게 감소되는 것을 확인할 수 있었다. This study was prepared to find out wettability and properties of defects on solder joints in N_2 conditions. The wettability of solder joints in N_2 condition was better than that in atmosphere condition, and when the flow rate of N_2 was increased, it is found that the wetting time got a little bit short and the wetting force got stronger as time passed. Also the rate of bridge defects was specially decreased in N_2 conditions, showing the decreasing ratio of 25∼76%. The solder joints were stabilized and the rate of defects was decreased by cause to increasement of wetting force in N_2 conditions.

77K와 상온에서 CO(NH₂)₂의 ¹⁴N Pulsed NQR 연구

강재필,박영민,전인,김성재,최숙자,박현진,송승기,서용문 명지대학교 자연과학연구소 1996 자연과학논문집 Vol.13 No.-

77K와 상온에서 CO(NH₂)₂분말 시료의 ??N Pulsed NQR실험을 하여 위와 아래 공명 진동수, 핵 사중극 결합상수, 비대칭 인자, 스핀-스핀 완화시간, 결정 격자 진동에서의 평균 비틀림 진동수, 진동자의 관성 모먼트 등을 구하였다. 공명 진동수의 온도 의존성은 전형적인 Bayer이론의 격자 진동에 의한 주파수 변화를 보였다. Bayer-Kushida이론의 고온근사식을 실험값에 적용하여 OK에서 공명 진동수 ν??와 ν??를 구했으며, 77K와 상온에서의 스핀-스핀 완화시간 T₂를 관측했다. 상온에서 T₂의 감소는 결정 내의 reorientation motion과 관련이 있을 것으로 보인다. Upper and lower resonance frequencies, nuclear quadrupole coupling constants, asymmetry parameters, spin-spin relaxation time, average torsional frequency in the crystal lattice motion and moment of inertia in the oscillator are found for CO(NH₂)₂powder sample by using ??N Pulsed NQR(Nuclear Quadrupole Resonance) technique at 77K and room temperature. Temperature dependence of resonance frequencies showed frequency variation in agreement with the typical Bayer's theory in lattice motion. Resonance frequencies ν?? and ν?? at OK were obtained by fitting the high temperature approximation of Bayer-Kushida theory to the experimental data and spin-spin relaxation time (T₂) was observed at 77K and room temperature. Decrease of T₂at room temperature was explained by the effect of reorientational motion in the crystal lattice.

칼슘과 아연으로 치환된 Y0.8 Pr0.₂ Ba₂ Cu₃ O7_δ 의 전기 및 자기적 성질에 관한 연구

김성재,전인,박영민,강재필,노태호,박현진,최숙자,송승기 명지대학교 자연과학연구소 1996 자연과학논문집 Vol.14 No.-

전이온도가 72K인 고온초전도체 Y?P?B?Cu?O?에서 초전도성을 감소시키는 Pr원소자리에 Ca과 Zn를 적당히 치환시켜 자기적 성질을 연구하였다. 초전도 전이온도(Tc)는 Ca이 치환된 시료의 경우 80~85k의 범위에서 측정되었으며, Zn가 치환된 경우에는 35~49K의 값을 보였다. 비저항의 온도 변화로부터 결정된 전기적 전이온도는 온도에 대한 자기모우먼트으 변화에서 구한 자기적 전이온도와 비슷한 값을 보였다. 자기이력곡선으로부터 Bean의 모델을 이용하여 Hcl(저임계자기장), Hc?(고임계자기장), 반자성정도, 임계전류밀도를 측정하였다. 이러한 성질들은 시료 내에 Ca의 치환량이 많아질수록 증가하였으며, Zn가 많아질수록 급격히 감소하였다. 특히 임계전류밀도는 x=0.0인 시료는 1.60x10?A/㎠이었으며 Ca이 치환된 시료는 1.30~1.98x10? A/㎠, Zn가 첨가된 시료는 3.5x10?~1.3x10?A/㎠의 값으로 계산되었다. 이것은 시료 내에서 Ca은 초전도성을 증가시키고, Zn는 초전도성을 감소시키는 것을 의미한다. We have studied magnetic properties as a appropriate substitute of Ca and Zn element for Prelement which reduces superconducting properties in the high-temperature superconductor Y?Pr?Ba?Cu?O? of transition temperature 72K. When Ca is put into, the critical temperature(Tc)showed the value of measurement at the range of 80~85K while for Zn the Tc had the range of 35~49K. The electric critical temperature determined by the temperature dependence of resistivity had a similar data to the magnetic field), Hc?(high critical magnetic field), diamagnetic ratio and critical current density have observed by Bean's model from the magnetic hysterisis curve. These properties were increased with adding Ca and abruptly decreased with adding Zn in the samples. Especially, the critical current density of x=0.0 sample was calculated at 1.60x10?A/㎠ and those of the other Ca-added samples at the range of 1.30~1.98xA/㎠and those of Zn-added samples at the range of 3.50x10?~1.30x10?A/㎠. These mean that Ca increases supercondecting properties in the sample and Zn element decreases them.

조류와 유기화합물의 동시제거를 위한 흡착 - DAF 복합공정

이재욱,곽동희,최승필,정흥조 대한상하수도학회 2004 상하수도학회지 Vol.18 No.2

Dissolved air flotation (DAF) is an effective solid/liquid separation process for low density floc particles such as algal, color-alum and clay-alum flocs produced from low turbidity water. The removal of taste and odorcausing organics (2-mthylisoboneol and geosmin) originating from algae in drinking water is a local and worldwide concern. Although DAF has been effectively applied for the removal of suspended solid, its application for the treatment of dissolved organic carbon is very limited. In this study, a new hybrid system consisting of adsorption and DAF processes was introduced for the simultaneous removal of algae and taste and odorcausing organics. Powdered activated carbon (PAC) was used as an adsorbent. In this proposed system, the major concern of eliminating the spent PAC from the system was also addressed. It was found that zeta potential of algae and PAC was increased with coagulant dosage, and the removal efficiency in DAF was also enhanced up to 90-95% under the given experimental conditions. Based on this study, the hybrid process was found to be a promising technology for the simultaneous removal of algae and dissolved organic pollutants.

저장기간에 따른 오이김치의 비타민 C 및 클로로필 함량변화

박미란,이연정,고즈쿠에 노부유키,한재숙,최석현,허성미,한경필,최수근 한국식생활문화학회 2004 韓國食生活文化學會誌 Vol.19 No.5

This study was carried out to examine the changes of pH, chlorophyll, chlorophyll patterns and ascorbic acid contents, and sensory evaluation in Oi-Kimchi by the different periods of storage. The contents of chlorophyll a and b were 52.2% and 14.44% at storage 0 days, 20.67% and 16.99% at storage 11 days, 0% at storage 14 days, and decreased with storage times increased. But, phephorbide a and b were increased with storage times increased until storage 11 days, and were 28.44% and 1.25% at storage 0 days, 42.63% and 15.79% at storage 11 days, 0% at storage 12, 14 days. The contents of ascorbic acid were increased until storage 4 days, but afterwards were decreased with storage times increased, and were 2.57㎎% at storage 0 days, 5.49㎎% and 2.95㎎% at storage 11 days, 0% at storage 14 days. Sensory evaluations of appearance, flavor, taste, texture, overall acceptability showed the highest at storage 8 days, and disliked after storage 10 days.

FET형 반도체 마이크로센서 개발(Ⅱ)

손병기,이흥락,박이순,조진호,이성필,최평,서화일,고성택,박재윤,서장수,김창수 경북대학교 센서기술연구소 1994 연차보고서 Vol.1994 No.-

현재 의료진단, 화학공정의 모니터링이나 환경공학적 감시 및 제어 등의 분야에서 사용되고 있는 기존의 센서는 고가이며 용적이 클 뿐만 아니라 분석시간이 길고 사용하기 까다로운 것 등 여러 가지 문제점이 있다. 또한 측정환경에 영향을 주지 않을 만큼 충분히 작으며 빠른 분석시간을 가진 센서를 필요로 하고 있다. 본 연구에서는 기존의 센서들의 난점을 극복할 수 있는 새로운 형태의 FET형 전해질(electrolyte : H^+, K^+, Ca^2+, Na^+)분석 시스템, 용존가스(O_2, CO_2)분석 시스템의 개발을 중점적으로 추진하며, FET형 압력센서, 습도센서, 방사형 온도센서 등의 개별 FET형 센서에 관한 연구도 병행하고자 한다. Recently various kinds of sensors have been developed, being applicated to their own purpose. There are lots of difficulties to apply them to measurements in which the real-time monitoring is required without disturbing the surrounding environment. FET type semiconductor sensors, fabricated by the semiconductor integration technologies, have many advantages for their miniaturization, standardization, mass-production and in vivo/in situ monitoring. They also hold a very proper configuration for multi-functional sensors or integrated smart sensors, and wide availability by forming various kinds of physical or chemical sensing materials onto their sensing gates.

완전 방실차단을 동반한 급성 심근염

이유선,정진옥,박용규,박형서,노상필,정승현,김정희,이재환,최시완,성인환 충남대학교 의학연구소 2003 충남의대잡지 Vol.30 No.2

급성 심근염환자에서 발행한 완전 방실차단을 영구 심장박동 조율기로 치료한 1예를 경험하였기에 문헌고찰과 함께 보고하는 바이다. Myocarditis, an inflammatory process involving the myocardal wall, may be caused by most infectious agents. Irrespective of its etiology, it presents commonly with evidence of heart failure, hypotension, and various electrocardiographic abnormalities. Patient with myocarditis may be asymptomatic or may have a rapidly progressive fatal disease. Medical management of patients with myocarditis includes specific therapy for underlying infection and control of the complication of myocarditis such as congestive heart failure and arrhythmia. Recently we had experienced myocarditis with complete atrioventricular block in 37-year-old man. Although he had shown complete recovery of heart failure, he had shown complete atrioventricular block, so we inserted permanent pacemaker. We report it with review of the literature.

FET형 반도체 마이크로센서 개발(Ⅲ)

손병기,이흥락,박이순,조진호,이성필,최평,서화일,박재윤,송경은,김창수 경북대학교 센서기술연구소 1995 연차보고서 Vol.1995 No.-

현재 의료진단, 화학공정의 모니터링이나 환경공학적 감시 및 제어 등의 분야에서 사용되고 있는 기존의 센서는 고가이며 용적이 클 뿐만 아니라 분석시간이 길고 사용하기 까다로운 것 등 여러 가지 문제점이 있다. 또한 측정환경에 영향을 주지 않을 만큼 충분히 작으며 빠른 분석시간을 가진 센서를 필요로 하고 있다. 본 연구에서는 기존의 센서들의 난점을 극복할 수 있는 새로운 형태의 FET형 전해질(electrolyte : H^+, K^+, Ca^2+, Na^+)센서소자 및 분석 시스템, 용존가스(O_2, CO_2)센서의 개발을 중점적으로 추진하였으며, FET형 압력센서, 습도센서 둥의 개별 FET형 센서에 관한 기초연구도 병행하였다. The conventional sensors have many problems such as high cost, large dimension, long analysis time and troublesome handling to apply to the fields of medical diagnosis, monitoring of chemical process and environmental monitoring/control. The main objects of this research are to develope a new FET type electrolyte(H^+, K^+, Ca^2+, Na^+)sensors, analysis system, and dissoved gas(O_2, CO_2)senors that can overcome the problems of the conventional sensors, and parallel basic researches on FET. type sensors such as pressure and humidity are also in progress.

The Story and Implications of the Korean Health Care Facility Counseling Project on People Living with HIV

Choi Jae-Phil,Lee Jung-Hui,An Jong Mi,Kim Jihyun,Won Nari,Choi Young Hwa 대한감염학회 2023 Infection and Chemotherapy Vol.55 No.2

In 2005, the Korea Disease Control and Prevention Agency (KDCA) launched “Health Care Facility Counseling Project on People Living with human immunodeficiency virus (HIV)” funded by the private-subsidy project for the prevention of acquired immune deficiency syndrome (AIDS) and sexually transmitted diseases to provide people living with HIV (PLWH) psychological support and counsel them about the disease and antiretroviral therapy (ART). Currently, 38 counseling nurse specialists work at 28 healthcare facilities for patient care. Of all PLWH in Korea, 71.9% received benefits from the Counseling Project. Adherence to ART medication (>95.0%), level of depression or anxiety, counseling coverage, and viral load status were monitored as common project indicators. Various specialized programs have been implemented in diverse facilities. This project has played a pivotal role in HIV care continuum and viral suppression policies, resulting in 95.9% of PLWH maintaining undetectable status (<40 copies/ml) in 2021. In this review, we present the chronology and fulfillment of this project, which will be an essential step for future planning in the context of aging and the chronic comorbid nature of HIV/AIDS.

Dysphagia Lusoria 1 예

최재필(Jae Phil Choi),박효진(Hyo Jin Park),김정환(Jung Hwan Kim),김기중(Ki Joong Kim),유영훈(Yung Hoon Yoo),이상인(Sang In Lee),박인서(In Suh Park) 대한소화기기능성질환·운동학회 2002 Journal of Neurogastroenterology and Motility (JNM Vol.8 No.1

Dysphagia lusoria (swallowing difficulty due to trick of nature) is used to describe the symptomatic compression of the esophagus from any anomalous vessel of aortic arch. Aberrant subclavian artery, the most common anomaly of aortic arch can cause dysphagia lusoria by its direct compression of the esophagus or its aneurysmal dilatation. Patient with dysphagia lusoria can be treated with dietary modification, medications (antireflux drugs, prokinetics) in early symptomatic phase, and with surgical correction (via thoracic or extrathoracic approach) in late symptomatic phase or selective cases. We experienced a case of 44-year-old man who suffered from progressive swallowing difficulty for solid foods. We evaluated the possible causes of motor or mechanical dysphagia by esophageal manometry, esophagography, esophagogastroduodenoscopy, and chest computerized tomography. We finally diagnosed this case as dysphagia lusoria due to group 3 aberrant left subclavian artery.(Korean Journal of Gastrointestinal Motility 2002;8:63-67)