Step Free Energy Change and Microstructural Development in BaTiO₃-SiO₂

Chang, Jaem Yung,Kang, Suk Joong L. Trans Tech Publications, Ltd. 2007 Key Engineering Materials Vol.352 No.-

<P>The effect of step free energy on the grain growth behavior in a liquid matrix is studied in a model system BaTiO3-SiO2. BaTiO3-10SiO2 (mole %) powder compacts were sintered at 1280°C under various oxygen partial pressures (PO2), 0.2, ~ 10-17 and ~ 10-24 atm. As the step free energy decreases with the reduction of PO2, it was possible to observe the change in growth behavior with the reduction of the step free energy. At PO2 = 0.2 atm, essentially no grain growth (stagnant grain growth) occurred during sintering up to 50 h. At PO2 ≈ 10-17 atm, abnormal grain growth followed stagnant grain growth during extended sintering (incubation of abnormal grain growth). At PO2 ≈ 10-24 atm, normal grain growth occurred. These changes in growth behavior with PO2 and the step free energy reduction are explained in terms of the change in the critical driving force for appreciable growth relative to the maximum driving force for grain growth. The present experimental results provide an example of microstructure control in solid-liquid two- phase systems via step free energy change.</P>

일측 폐이식 성견에서 혈역학과 체액조절 호르몬의 상관관계

서강석,박창권,송대규,배재훈,박원균 啓明大學校 醫科大學 2002 계명의대학술지 Vol.21 No.1

폐이식에 의한 체액이나 혈압의 변동 및 신경의 절단은 혈압 및 체액의 조절에 관여하는 호르몬의 분비에 영향을 미치리라 생각되어 좌일측 폐이식 시 이식폐에 분포하는 신경이 절단된 상태에서 폐이식 후 수용견의 혈역학적 변동이 ANP 및 ADH의 분비와 어떠한 상관관계가 있는지를 관찰하였다. 한국산 성견 12마리를 대상으로 좌일측 폐이식을 시행하였다. 공여폐의 보존은 low potassium dextrane glucose용액을 이용하여 10℃에서 20시간동안 보존한 다음 수용견에 이식하였다. 수용견의 좌측 폐를 적출하기 전과 후, 그리고 이식 후 재관류 30분, 2시간 후에 각각 혈역학 및 동맥혈 가스분압을 측정하였고, 동맥혈에서 ANP 및 ADH의 농도를 측정하였다. 동맥혈의 P_(O_2) 및 P_(CO_2)는 유의한 변동은 없었다. 대퇴동맥압을 재관류 후 30분에는 유의하게 감소하였고, 재관류 2시간 후에는 다소 회복세를 보이는 경향이었으며, 맥압은 비교적 유지되었다. 폐동맥압은 좌측폐 절제 시 이완기 폐동맥압은 변동이 없는 반면에 수축기 폐동맥압은 증가하였고, 재관류 시 폐동맥압은 어느 정도 회복되는 양상이었다. 심박출량은 좌측 폐절제 후에는 감소하였으며 재관류후에도 낮게 유지되는 양상이었다. 반면에 심박수는 유의한 변화없이 유지되었다. 전신혈관저항 및 폐혈관저항은 좌측 폐절제 후나 재관류 30분에 증가하였으며, 재관류 2시간 후 폐혈관저항은 회복되는 양상이나 전신혈관저항은 회복되지 못하였다. 혈중 ANP는 일측 폐절제 후 증가하였고, 재관류 후에는 점차 회복되는 양상을 보였고, ADH는 일측 폐절제 후, 30분에 증가한 후 회복되는 양상을 보였다. 동맥혈 ANP의 변동은 동맥혈 P_(O_2)및 P_(CO_2)와 상관관계를 보였고, ADH는 전신 동맥압의 변동과 상관관계가 있었다. 이상의 결과로 좌일측 폐이식 시에도 ANP 및 ADH는 혈역학적 변화와 연관하여 동맥압 및 체액의 조절에 생리적으로 관여하는 것으로 사료되며, ANP의 분비는 동맥혈의 저산소증 그리고 ADH의 분비는 동맥의 압수용기를 통한 신경성 조절의 영향을 받을 수 있는 것으로 생각된다. The purpose of this investigation was to study changes of plasma atrial natriuretic peptide (ANP) and antidiuretic hormone (ADH) in Korean mongrel dogs after a left single lung transplantation and to evaluate the correlation between hemodynamic factors and secretory responses of ANP and ADH. Arterial P_(O_2 and P_(CO_2) did not change significantly. Femoral arterial pressure decreased after 30 min of reperfusion and recovered slightly at 120 min, whereas pulse pressure did not change. After pneumonectomy, systolic pulmonary arterial pressure increased, whereas diastolic pulmonary pressure remained unchanged. Althought cardiac output fell following pneumonectomy and reperfusion, heart rate was unchanged. The secretion of plasma ANP initially increased follwoing pneumonectomy, but subsequently recoverd. In each subject, ANP values showed stronger correlation with arterial P_(O_2) than other hemodynamic parameters. The secretion of plasma ADH also initially increased (p<0.05) after 30 min of reperfusion and thereafter recoverd, showing the strongest correlation with mean femoral arterial pressure. The present results suggest that the secretion of ANP and ADH seem to be well regulated in accordance with hemodynamic changes after a single lung transplantation. Hypoxia and systemic arterial pressure are the prominent factors in the secretion of ANP and ADH, respectively.

국내 중소하천의 유사량 산정 공식 적용에 관한 연구

강창훈 ( Chang-hoon Kang ),장석환 ( Suk-hwan Jang ),신철식 ( Cheol-sik Shin ),이현기 ( Hyeon-ki Lee ),김월봉 ( Wol-bong Kim ) 한국환경기술학회 2013 한국환경기술학회지 Vol.14 No.6

유사란 하천수에 의하여 운반되는 토사를 말하며 유수에 의해 침식, 퇴적이 반복되는 결과를 낳는다. 최근 기후변화와 함께 대규모 홍수가 빈번해 짐에 따라 하천의 유사량이 커지고 4대강 사업처럼 대규모 하천사업으로 인한 하상변동이 심해지고 있다. 하천에서 총유사량 추정은 하상변동의 원인이 되기도 하고 수자원 개발 및 관리를 위한 하천계획에 필요한 기본적 요소이다. 하지만 국내에서는 대규모 하천에서의 유사량은 측정을 실시하고 있지만 중소하천의 경우 유사량을 실측하여 산정할 수 있는 시간적 경제적 부담 때문에 측정할 수 있는 한계가 있다. 본 연구에서는 경기북부에 위치한 차탄천, 포천천, 경기남부에 위치한 남양천의 각 유량에 따른 부유사를 채취하여 시료분석을 통한 결과와 이론식을 적용하여 비교 분석 하였다. 채취한 시료는 입도분석을 실시하였으며 현장 측정 자료와 실내실험 결과를 토대로 수정 아인슈타인공식을 적용한 BORAMEP 프로그램을 사용하여 총유사량을 산정하였다. 분석 결과, 3m³/sec 이하 유량에서는 Yang 공식이 실측자료와 일치성을 나타냈고 3m³/sec 이상에서는 Shen and Hung 공식이 잘 나타났다. 각 이론을 적용하여 총유사량을 추정하고, 실측치를 이용하여 비교·검토함으로써 국내 중소하천에 적합한 산정 방법과 경기북부 지역 중소하천의 유량-총유사량 관계식을 제시하였다. Sediment transport means that the materials of bed and suspended load in the river are transported by flow tractive force, which causes scour and deposition. As the climate changes and dramatic flood occurs frequently, the sediment transport has increased and river bed changed. Sediment transport estimation is essential for the water resources management as well as river bed morphology. However, it is difficult to measure the total sediment in the middle and small river due to time and economic constrain. In this study, field data which were observed in 3 different river in Kyunggi-do were analyzed for comparing with empirical equations. Particle distribution analysis were carried out for the collected the suspended loads. The simulation model BORAMEP(Bureau of Reclamation Automated Modified Einstein Procedure) were used for the total sediment estimation along the field data analysis. As a result, Yang`s equation corresponds to field data under 3m³/sec and the equation of Shen and Hung corresponds to results over 3m³/sec. The results showed the way how sediment were estimated and discharge-total sediment relationship was determined by regression analysis in small and middle river of Kyunggi province region.

시뮬레이션 평가 기준 및 방법에 따른 창세트 열관류율 비교

강혜숙(Kang, Hye-Suk),유동철(Yoo, Dong-Chul),이건호(Lee, Keon-Ho),장대희(Jang, Dae-Hee),최창호(Choi, Chang-Ho) 한국건축친환경설비학회 2015 한국건축친환경설비학회 논문집 Vol.9 No.5

The purpose of this study was to verify the suitability of the simulation test for domestic and international window-set U-values by discussing the input conditions and calculation methods for the same simulation test and comparing the calculated results for various window-sets. To this end, a total of 18 cases were selected, where glass, cavities, frames, spacers, windows sizes, etc, for double glazing fixed-windows and triple glazing fixed-windows have been changed. Then, domestic and international U-values by criteria were compared by performing a simulation using WINDOW&THERM, a certified program. The analytic results of domestic and international standards revealed that domestic standards and NFRC used the calculation method through the Edge area and that CEN used linear thermal transmittance(ψ) as a calculation method. In the Indoor and outdoor temperature conditions, domestic standards and CEN were similar but NFRC was somewhat different. The results of comparing U–value errors based on the Korea test found NFRC -6.22% ~+9.50%, CEN -4.98% ~ -1.23%. The U-value of the case calculated based on CEN standards tended to be mostly higher than that in domestic conditions. This tendency may have been caused by the difference between convective heat transfer coefficient and frame effective thermal conductivity in air space. The results of the domestic standards-applied simulation of window-set thermal transmittance showed an error rate within 10%, compared to NFRC and CEN. The above study confirmed the suitability of the simulation test for domestic window-set U-values.

A Case of Occupational Hypersensitivity Pneumonitis Associated with Trichloroethylene

Jae, Young,Hwang, Eu Dong,Leem, Ah Young,Kang, Beo Deul,Chang, Soo Yun,Kim, Ho Keun,Park, In Kyu,Kim, Song Yee,Kim, Eun Young,Jung, Ji Ye,Kang, Young Ae,Park, Moo Suk,Kim, Young Sam,Kim, Se Kyu,Chang, The Korean Academy of Tuberculosis and Respiratory 2014 Tuberculosis and Respiratory Diseases Vol.76 No.2

Trichloroethylene (TCE) is a toxic chemical commonly used as a degreasing agent, and it is usually found in a colorless or blue liquid form. TCE has a sweet, chloroform-like odor, and this volatile chlorinated organic chemical can cause toxic hepatitis, neurophysiological disorders, skin disorders, and hypersensitivity syndromes. However, the hypersensitivity pneumonitis (HP) attributed to TCE has rarely been reported. We hereby describe a case of HP associated with TCE in a 29-year-old man who was employed as a lead welder at a computer repair center. He was installing the capacitors on computer chip boards and had been wiped down with TCE. He was admitted to our hospital with complaints of dry coughs, night sweats, and weight losses for the past two months. HP due to TCE exposure was being suspected due to his occupational history, and the results of a video-associated thoracoscopic biopsy confirmed the suspicions. Symptoms have resolved after the steroid pulse therapy and his occupational change. TCE should be taken into consideration as a potential trigger of HP. Early recognition and avoidance of the TCE exposure in the future is important for the treatment of TCE induced HP.

디지털 FM이동통신에서의 검파후 최대비합성법의 구성

강석규,주창복 慶南大學校 附設 工業技術硏究所 1999 硏究論文集 Vol.17 No.-

본 논문에서는 검파후 최대비합성법에 의한 지연검파와 주파수검파의 경우에 대한 합성후의 SNR 관계식들을 관찰하고 이것들을 실현하는 실용적인 구성예를 보였다. 또한 이러한 구성에서 합성후 SNR의 열화특성과 이득특성 보이므로써 최대 SNR를 얻기위해 필요로 하는 가중계수의 변화를 얻기 위해 필요한 최대비합성에서의 검파기입력 SNR의 측정을 필요로 하지 않는 실용적인 검파후 최대비합성 수신검파기의 구성법이 합리적이라는 것을 보였다. This Paper observed the related formulas of SNR branched postdetection maximal ratio combining method in case of the delay detection and frequency detection and showed the practical configuration for the postdetection maximal ratio combining receiver. The defined SNR degradation characteristics after branches combining from the formulated results showed the practical postdetection maximal ratio combining structure is reasonable without the necessity measuring the input SNR of each branches to obtain the maximum SNR

내시경적 점막절제술로 치험한 식도 과립상 세포종 1례

강혁주,김성욱,최석진,이중현,장재식,서영범,윤병구,박건욱,김성자,김용섭,강승완,이구,양창헌,이창우,김욱년,이광헌,서정일 동국대학교 의학연구소 2000 東國醫學 Vol.7 No.-

과립상 세포종은 Schwann 세포 기원으로 생각되며 인체에 비교적 드물게 발생한다. 과립상 세포종은 전신 어느 곳에서나 발견될 수 있으나 주로 혀, 구강, 피부 혹은 유방 등에서 호발하며 드물게 위장관에서 발견된다. 위장관에서는 식도에서 가장 호발하며 다음으로 위, 대장 순이다. 과립상 세포종은 대부분, 특히 위장관에서는 양성이며 소수의 악성 병변이 보고되었다. 이러한 이유와 함께 수술 전의 진단이 어렵기 때문에 과립상 세포종에 대한 근본적인 치료는 현재까지 외과적 절제술이다. 최근에 시도되는 치료방법들로는 내시경적 레이저 치료, 용종절제술, 내시경적 점막 절제술 등이 있다. 저자들은 상부 소화관 내시경검사를 시행하여 식도 과립상 세포종을 진단하고 내시경적 점막 절제술을 시행하여 합병증 없이 퇴원하여 현재 재발없이 경과 관찰중인 1례를 경험하였기에 보고하는 바이다. Granular cell tumors, which occur infrequently, are probably of Schwann cell origin. They can occur almost anywhere in the body but usually affect the tongue, oral cavity, skin, or breasts and are rarely found in the gastrointestinal tracts. The esophagus is the most frequent gastrointestinal site, followed by the stomach and the colon. Granular cell tumors are generally benign, especially in the gastrointestinal tract, some malignant lesions have been reported. For this reason, and also because preoperative diagnosis is difficult, the standard treatment for granular cell tumor has until now been surgical excision. In recent years, other therapeutic methods is endoscopic laser therapy (ELT), polypectiomy, endoscopic mucosal resection (EMR). We report a case of esophageal granular cell tumor which was diagnosed by an endoscopy and managed using an endoscopic mucosal resection without complication.

위암에서 p53 유전자의 변이에 대한 연구

강현욱,김창진,정문석 순천향의학연구소 1997 Journal of Soonchunhyang Medical Science Vol.3 No.2

The pathogenic mechanisms of gastric carcinoma, which is the most common malignant tumor in Korea, have not been completely elucidated. Recently the carcinogenic mechanisms have been explored in depth of genetic mutations. Several lines of evidence showed that oncogenes and anti-oncogenes played some roles in the pathogenesis of human malignant tumors. Among several anti-oncogenes, p53 is the most commonly mutated in varoius human malignat tumors. This study is conducted to see the rate of p53 gene nutation in gastric carcinoma by the loss of heterozygosity(LOH). The DNA is extracted from the cells harvested from paraffin block sections. The exon 4 of p53 is amplified by polymerase chain reaction(PCR) and the product is digested with Tha I endonuclease. Among 20 informative cases, 7 (35%) revealed loss of heterozygosity. Among 14 cases of well differentiated carcinoma and 6 cases of poorly differentiated carcinoma, LOH was observed in 5 cases (36%)and 2 cases (33%) respectively. The above results revealed that p53 mutation plays some roles in the pathogenesis of gastric carcinoma. But to elucidate the roles genetic mutaton in the pathogenesis of gastric carcinoma, more numbers of different exons should be searched.

西上面一帶의 나방相에 대하여

康昌暎,朴重錫 慶尙大學校 기초과학연구소 1987 基礎科學硏究所報 Vol.3 No.-

Seasonal changes of the moth fauna in relation to time, air temperature and relative humidity were investigated in So˘sang-myo˘n, Hamyang-gun, Kyo˘ngsangnam-do, Korea from March 4, to October 15, 1963. This study was based on an examination of 1,533 individuals. 1. The collected and identified moths were 201 species, 154 genera, 16 families and Autographaamurica Staudinger turned out to be hftherto unreported in Korea. The dominant species was Jankowskia fuscaria Leech and the dominant family was Noctuidae. 2. Appearance pattern was classified to 6 types according to the collecting frequency, and the collecting numbers of individuals were most abundant in August and through summer. 3. The moths appeard most abundantly from 21 to 23 o,clock through the year, aod at 22 and 21 o,clock in summer and autumn, respectively. 4. The collected numbers of individuals were most at 20℃-26℃. 5. the collected numbers of individuals were none below 50% of the relative humidity, increaseed from 70%, and most at 90%.

들깨잎의 揮發性 香氣成分에 關한 硏究

姜興順,林順英,南昌祐,尹錫權,邊時明 同德女子大學校 1995 同大論叢 Vol.25 No.1

To investigate the volatile flavor components of perilla leaves, analyses of kinds of cultivar by GC, GC/MS, UV, IR and NMR were carried out. The results obtained were summarized as follows : 1. The essential oils were extracted with diethyl ether after steam disillation. 2. The identified volatiles include 10 hydrocarbones, 6 alcohols, 3 aldehydes, 2 ketones and 1 miscellaneous components. 3. The major volatile component perilla ketone was identified by UV, IR and NMR spectrum. 4. The perilla ketone were identified in Suwon 8, 19, 21, 23, 24, 25, 26 and purpurea while perillaldehyde was identified in purpurea only.