인쇄회로기판의 전과정평가

박필주,이보삼,이건모 한국전과정평가학회 2000 한국전과정평가학회지 Vol.2 No.1

C전자에서 제조되는 인쇄회로기간에 대하여 원료채취부터 제품생산까지의 cradle to gate 전과정평가를 수행하였다. 대상제품은 유리섬유 및 에폭시 수지를 이용하여 HDD용으로 제조되는 4층 도체패턴의 PCB이다. 데이터는 현장 데이터를 적용하였으며, 현장 데이터 취득이 어려운 경우 데이터베이스를 사용하였다. 영향평가는 분류화, 특성화, 정규화 및 가중치부여 단계로 수행되었으며, 고려된 영향범주는 ARD, GW, OD, POC, Acid, Eut, ET 및 HT이다. 불확실한 데이터 값의 변화가 전체 결과값에 미치는 변화정도를 알아보기 위하여 민감도 분석을 수행하였다. LCA 수행 결과 PCB 제조공정은 OD 범주를 제외한 모든 영향범주에서 가장 큰 영향을 미치는 것으로 나타났다. 이는 PCB 제조시 사용된 저녁에서 기인한 값이다. PCB 제조시 사용되는 화학약품은 질량기준 사용량은 많지만, 환경에 미치는 영향은 적은 것으로 나타났다. 사용된 데이터에 따른 민감도 분석 결과 PCB 제조공정의 전력사용량은 GW 및 POC 범주에 매우 민감하게 나타났으며, 할당방법에 의한 분석 결과 전 영향범주에서 25% 이내의 차이를 나타냈다. Life Cycle Assessment on Printed Circuit Board produced in C Electronics Co. was carried out. The system boundary encompasses raw material acquisition to the manufacturing of PCB(or cradle to gate). The product is FR4 PCB used for a component o HDD. FR is a mixture of glass fiber and epoxy resin. Generally site specific data were applied. However, database were used when it is hard to get site specific data. Impact assessment was carried out consecutively as classification, characterization, normalization and weighting. Considered Impact categories are ARD, GW, OD, POC, Acid, Eut, ET, HT. Sensitivity analysis is accomplished to find out how the variation of unreliable data affects the result of LCA. The PCB manufacturing was identified as the most contributing activity to all impact categories except OD. This is mainly due to the electricity consumed in the manufacturing phase. Even though the large amount of chemicals are used for PCB manufacturing in mass, environment impact of those chemicals is much less than they were consumed. he sensitivity of data method shows that the amount of electricity consumed in the PCB manufacturing is considerably sensitive to POC and GW. The sensitivity results of allocation method in th PCB manufacturing on the LCA indicate approximately 25% difference in all impact categories.

Cs이 흡착된 Si(111)7×7표면에 대한 RHEED연구

박종윤,이순보,이경원,안기석,강건아 성균관대학교 1991 論文集 Vol.42 No.1

Cesium-adsorbed surface structures on Si(111)7×7 were investigated at room and high temperatures(200∼700℃) by RHEED. The RHEED patterns of Si(111) 7×7 was changed to the modified 7×7 and the 1×1 patterns with increasing the deposition times of Cs at RT. It was observed that the structure of the Cs-adsorbed Si (111) 7×7 surface at saturation coverage is the 1×1 structure at RT. The ◁그림삽입▷(원문을 참조하세요) 1 and 1×1 structures appeared successively at the adsorption temperature of 300℃, 350∼400℃ and 450℃, respectively. After subsequent heating of 1×1 surface above 550℃ and of ◁그림삽입▷(원문을 참조하세요) surface above 600℃, each RHEED pattern gradually returned to the original Si(111)7×7 pattern. 상온 및 200∼700℃의 Si(111)7×7 표면에 Cs(Cesium)을 증착하였을 때 표면격자구조의 변화를 RHEED로 관측하였다. Cs 증착시 Si(111)7×7 기판의 온도가 상온인 경우, 포화 덮임률에 도달했다고 추정되는 일정 증착시간 전에는 원래의 깨끗한 Si(111)7×7 패턴과 거의 유사한 변형된(modified) Si(111)7×7-Cs 패턴이 관측되었다. 그후 포화 덮임률에서는 1×1패턴이 관측되고 증착량을 증가시켜도 패턴의 변화는 관측되지 않았다. 이 구조를 다시 annealing시키면 약 550℃부터 서서히 원래의 7×7구조로 되돌아가기 시작한다. Si(111)7×7기판의 온도를 220∼700℃로 유지하면서 Cs을 증착시킨 경우에 약 250℃까지는 상온에서와 비슷한 변형된(modified) 7×7이 관측되고 약 300℃에서는 ◁그림삽입▷(원문을 참조하세요) 350∼400℃ 정도에서는 ◁그림삽입▷(원문을 참조하세요)과 3×1이 겹쳐셔 관측되었다. 그리고 450℃ 이상에서는 1×1구조가 관측되었다. 이때 약 300℃에서 형성된 ◁그림삽입▷(원문을 참조하세요) 350℃에서 형성된 ◁그림삽입▷(원문을 참조하세요) 3+3×1 구조는 약 500℃ 정도까지 다시 annealing함에 따라 다리 1×1구조로 상전이가 일어난후, 약 600℃부터 원래의 7×7의 초격자점들이 나타나기 시작했다. 이들 결과로부터 Si(111)7×7 표면에 Cs을 증착하는 경우에는 일정한 포화 덮임률(saturation coverage)이 있는 것으로 추정되고, 이 덮임률에서 관측된 고온에서의 상전이는 증착량(증착시간)에는 무관하고 온도에만 의존함을 알 수 있었다. 또한 1×1 구조와 ◁그림삽입▷(원문을 참조하세요) 구조에 대하여 Cs의 탈착은 각각 약 550℃와 600℃에서 일어나기 시작하여 700℃에서 완전히 탈착됨을 알 수 있었다.

K이 흡착된 Si(111)7×7표면에 대한 RHEED 연구

박종윤,이순보,이경원,안기석,신익조,강건아 성균관대학교 1990 論文集 Vol.41 No.2

상온 및 200℃∼600℃의 Si(111) 7×7 표면에 칼륨(K)을 증착하였을 때의 표면격자구조 변화를 RHEED로 관측하였다. K 증착시 Si(111)7×7 기판의 온도가 상온인 경우, 어느 일정한 증착시간(포화덮임률에 도달했다고 추정되는 증착시간)이 지난 후에는 원래의 깨끗한 Si(111)7×7 패턴과 유사한 Si(111) 7×7-K 패턴이 관측되었고, 증착시간을 증가시켜도 RHEED 패턴은 변화하지 않았다. 이것을 annealing하면 350℃까지는 RHEED 패턴에 변화가 없다가 그 이상의 온도가 되면 서서히 원래의 7×7 패턴으로 되돌아가기 시작한다. Si(111) 7×7기판의 온도를 200℃∼600℃로 유지하면서 K을 일정시간(450℃에서 3×1이 형성되는 증착시간)이상 증착시킨 경우에 250℃까지는 상온의 경우와 비슷한 형태의 변형된 7×7 패턴이 관측되고, 300℃∼550℃일때는 3×1, 550℃ 이상에서는 1×1 구조가 관측되었다. 이때 300℃∼550℃에서 형성된 Si(111) 3×1-K 구조는 450℃에서 1분 정도 annealing 하면 항상 Si(111) 1×1-K 구조로 상전이가 일어남을 관측하였다. Potassium adsorbed surface structures of Si(111) 7×7 surface at room and high temperatures(200℃∼600℃) were investigated by RHEED. Potassium adsorption on the Si(111) 7×7 surface to saturated coverage at room temperature changed the RHEED pattern of Si(111) 7×7 to Si(111) 7×7-K. Subsequent heating of the Si(111) 7×7-K surface above 350℃ results in a Si(111) 7×7 with desorbing K. The RHEED pattern of the K-adsorbed on the Si(111) 7×7 surface up to the adsorption temperature of 250℃ was the modified 7×7 pattern, quite similar to that of the Si(111) 7×7-K, observed at room temperature. The 3×1 structure was observed in the temperature of adsorption between 300℃ and 550℃. Regardless of the adsorption temperature, a phase transition always took place from the Si(111) 3×1-K structure to Si(111) 1×1-K after annealing at 450℃ over 1 minute.

고두께 유리-실리콘의 대면적 양극접합에 관한 연구

김건년,이보나,박효덕,신상모,이근혁,권혁채 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

In this paper, we studied the anodic bonding of 5-inch silicon and #7740 Pyrex glass wafers with a thickness of 3mm by using the EV501 bonder and the Karl Suss SB6 bonder. The test conditions for anodic bonding of the EV501 bonder system with a full field electrode were temperature of 400 ℃ and voltage of 800V in a chamber pressure of 1X10^(3)mbar. The SB6 bonder with a star shaped electrode was tested at the temperature and voltage of 450 ℃ and 1300V in the atmosphere, respectively. As the results of test, we obtained the void free samples regardless of shape of substrates such as etched wafers with cavities and drilled glasses with holes.

집적화된 실리콘 압력센서의 출력전압 보상파라미터 추출 및 그 특성

이보나,김건년,박효덕,신상모,이경탁,김찬,권혁채,이상조,박현주 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

An integrated silicon pressure sensor has been designed, fabricated and tested. The signal conditioning circuits were designed to include calibration and temperature compensation of output voltage through trimming of diffusion and ion-implanted resistors. Before trimming of resistors, the compensation parameters such as pressure sensitivity, temperature coefficient of pressure sensitivity, temperature coefficient of piezoresistors and pressure sensitivity of piezoresistors were measured. Then offset voltage, span, and temperature coefficients of offset voltage and span were calibrated by trimming of resistors. The measured output voltage met our design specification and simulation value above room temperature. But, the measured output voltage at -30°C deviated from our design specification and simulation value because the offset voltages were found to vary randomly as a function of temperature.

Si Bulk Micromachining을 위한 Wafer Rolling Etching 및 그 특성

김건년,이보나,박효덕,신상모,공경준,장동근,김병철,권혁채,이봉희 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

A wafer rolling etching system for the silicon bulk micromachining has been designed and fabricated. The silicon diaphragms were anisotropically etched in a 24.5 weight percent KOH solution. Compared to the conventional KOH etching systems, pyramidal hillocks, and wave-shaped structures on the etched surfaces were greatly reduced by using this system. After etching for time of 438 minutes, the average etched depth and the etch-rate were measured to be 537μm and 1.22μm/min, respectively. The average etching uniformity of etching depth was 0.87% in 5-inch wafer. Our results showed that the wafer rolling method enhanced etch uniformity and etch rate.

Furosemide 및 Hydrochlorothiazide가 家兎 賢皮質의 Na-K-ATPase 活性에 미치는 影響

金寶年,劉寬熙,朴海根 충남대학교 자연과학연구소 1984 忠南科學硏究誌 Vol.11 No.2

The furosemide and hydrochlorothiazide are well known diuretics that inhibit the sodium active reabsorption in the renal tubules. Therefore it was suggested that they had a effect on the Na-K-ATPase activity, but the reports of these drugs on the Na-K-ATPase activity are rare. Author attempted to investigate the action of furosemide and hydrochlorothiazide on the Na-K-ATPase activity in the rabbit renal cortical homogenate. The results were summarized as follows: 1. The control values of Na-K-ATPase activity in the renal cortical homogenate were 1.80±0.27μM pi/10 min/㎎ protein in experimental group of furosemide and 1.58±0.29μM pi/10 min/㎎ protein in that of hydrochlorothiazide. 2. Furosemide tended to increase the Na-K-ATPase activity but was not statistically significant. From the above results, it was suggested that furosemide and hydrochlorothiazide had a diuretic action without the influence of Na-K-ATPase activity.

Changes in Dynamic Foot Pressure After Surgical Treatment of Valgus Deformity of the Hindfoot in Cerebral Palsy :

Park, Kun Bo,Park, Hui Wan,Lee, Ki Seok,Joo, Sun Young,Kim, Hyun Woo Journal of Bone and Joint Surgery 2008 Journal of bone and joint surgery Vol.90 No.8

<P>BACKGROUND: Calcaneal lengthening osteotomy and extra-articular arthrodesis of the subtalar joint are two methods used for the correction of valgus deformity of the heel and forefoot abduction. The purpose of this study was to compare the operative results of these procedures in patients with cerebral palsy who were able to walk. We focused primarily on changes in radiographic parameters and how altered mobility of the subtalar joint by the two operative methods would modify pressure distribution over the plantar surface of the foot. METHODS: A total of eighty-one feet in forty-seven patients were included in the study. The mean age at the time of surgery was eight years and one month, and the mean follow-up period was thirty-nine months. The subjects were divided into two groups; Group I consisted of thirty-seven feet in twenty-two patients who underwent a calcaneal lengthening osteotomy, and Group II comprised forty-four feet in twenty-five patients who underwent an extra-articular subtalar arthrodesis. Preoperative and final follow-up radiographs and dynamic pedobarographs were used to evaluate the results. RESULTS: The feet in both groups were found to be similarly deformed before surgery, by radiographic measurements and dynamic foot-pressure analysis. Both operative procedures led to improved radiographic indices; however, calcaneal pitch failed to improve after the subtalar arthrodesis. After surgery, the relative vertical impulse was decreased for the hallux, first metatarsal head, and medial aspect of the midfoot in both groups, while it was increased for the lateral aspect of the midfoot and calcaneus. On the other hand, postoperatively, the relative vertical impulse of the medial aspect of the midfoot was higher and the relative vertical impulse of the first through fourth metatarsal heads was lower in the group that had subtalar arthrodesis compared with the group that had a calcaneal lengthening osteotomy and the normal control subjects. CONCLUSIONS: Extra-articular subtalar arthrodesis appears to be an effective means to achieve predictable correction of severe valgus deformity of the heel in patients with cerebral palsy who are able to walk; however, supination deformity of the forefoot remains and calcaneal equinus is not corrected. On the other hand, we believe that the calcaneal lengthening osteotomy is the treatment of choice because postoperative foot-pressure distribution more closely approximates the normal foot-pressure distribution.</P>

An accessory limb with an imperforate anus

Kun-Bo Park,Yeon-Mee Kim,Ji-Yong Park,Mi-Lim Chung,Yu-Jin Jung,So-Hyun Nam 대한외과학회 2014 Annals of Surgical Treatment and Research(ASRT) Vol.87 No.4

Congenital accessory limbs are very rare anomalies with many causative factors. We describe the case of a 1-day-old female neonate?born to a healthy, 27-year-old mother?who presented with an accessory limb (foot) attached to the buttock and an imperforate anus. We also provide a review of the relevant literature.

Estimates of the Photo-Response Characteristics of a Non-Fully-Depleted Silicon p-i-n Photodiode for the Near Infrared Spectral Range and the Experimental Results

Kun-Sik Park,노광수,Bo-Woo Kim,황인갑,Jin-Yeong Kang,Jong-Moon Park,Yong-Sun Yoon 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.4

We have estimated the responsivity and the rise time of a non-fully-depleted silicon p-i-n photodiode. The estimate of the rise time was done by considering the undepleted intrinsic layer resistance and the drift velocity at low electric field. Our research shows that there exists an optimum intrinsic layer resistivity for the fastest photo-response characteristics at a given condition. The maximum responsivity is 0.72 A/W and the fastest rise time is 14 ns for a 24-V operation voltage at a 900-nm wavelength when an 80-μm depletion width is formed on a high-resistive, n-type wafer of 380 μm in thickness. Based on our considerations, we fabricated a high-performance silicon p-i-n photodiode for near IR measurement and analyzed its characteristics. In spite of the optical loss caused by the IR filter, the responsivity for a 900-nm wavelength was 0.67 A/W, and the rise time was about 20 ns at 24 V. These values were well consistent with our estimates when are considered the parasitic capacitance caused by the package, and were excellent compared with those from conventional photodiodes.