• 한국대기환경학회지
• /
• 제8권1호
• /
• pp.84-91
• /
• 1992

Hydrodesulfurization of thiophene was studied over $Ni-W/TiO_2-ZrO_2$ catalysts in a fixed bed flow reactor. The ranges of experimental conditions were at the temperatures between 200$^\circ$C and 360$^\circ$C, the pressures between 20 X $10^5$ Pa. The catalysts were reduced with the flow of 10 L/hr of $H_2$ at the temperature of 350$^\circ$C. It was found that $TiO_2-ZrO_2$ supported catalysts had similar activity to $\gamma-Al_2O_3$ supported. The largest surface areas and the highest acidity occured as the binary oxides were mixed with equal molar ratios. The HDS increased with increasing temperatures, pressures and contact times.

• Journal of Chest Surgery
• /
• 제28권11호
• /
• pp.963-966
• /
• 1995

Ischemia reperfusion injury occurs in various diseases. The role of oxygen free radicals in IR injury of the lung has been spotlighted and many studies have been performed. In this study, we tried to prepare a stable rat lung model for IR injury, focusing on surrounding conditions as hilar stripped left lung, clamped left pulmonary artery and bronchus,and declamped after determined period was passed, and right main pulmonary aretery was clamped. Arterial blood gas analyes were performed at 1, 10, 20, 30, minutes after reperfusion. Before clamping, PaO2 was 95 to 120 mmHg in all animals. There were six groups; Group I : temperature 15o C, and 120 minutes clamping, Group II: 20 oC, and 120 minutes clamping, Group III : 25 oC, and 120 minutes clamping, Group IV : 15oC, 90 minutes clamping, Group V : 20 oC, 90 minutes clamping,Group VI: 20 oC, 75 minutes clamping. Each groups contained 10 Sprague Dayley rats. The humidity was maintained 100 % as circulation imerged isotonic Hartmann`s solution of the pleural cavity. In group IV, V, and VI, PaO2 decreased significantly in all animals immediately after reperfusion, but 43 % survived till 10 minutes after reperfusion, it was 74.0$\pm$5.7, 73.3$\pm$10.8,and 88.2$\pm$17.7 mmHg. Pulmonary edema was observed histologically in 2/10 animals in group IV, 6/10 in group V , 3/10 in group VI, 9/10 in group I, and the other lungs showed all edema. We established a stable model by setting ischemic time,and temperature, between 75 to 90 minutes,15 to 20o C, and isotemperature Hartmann`s solution immersion of the pleural cavity.

• 센서학회지
• /
• 제4권2호
• /
• pp.7-13
• /
• 1995

MOSFET의 전장효과와 압전물질의 압전효과를 결합한 새로운 FET형 반도체압력소자(PSFET : pressure sensitive field effect transistor)를 제조하고 동작 특성을 조사하였다. PSFET의 압전박막은 RF 마그네트론 스퍼터링으로 ZnO박막을 약 $5000{\AA}$ 게이트 위에 성막하였다. ZnO 압전박막의 최적 c-축 배향분극 구조를 얻기 위한 막 제조조건은 기판온도가 $300^{\circ}C$, RF 전력이 140W, 작업 분위기압은 5mtorr였으며, 플라즈마가스는 아르곤이었다. 제조된 PSFET는 적용된 압력범위($1{\times}10^{5}\;Pa{\sim}4{\times}10^{5}\;Pa$)에서 비록 감도는 낮으나 비교적 안정한 동작특성을 나타내었다.

• Journal of Microbiology and Biotechnology
• /
• 제12권3호
• /
• pp.457-462
• /
• 2002

Low Electromagnetic Field (EMF) intensity in the range of $1{\mu}T\;to\;10{\mu}T$(Tesla) was found to enhance the growth of CHO cells and the production of tPA in batch and perfusion cultivations. At $1{\mu}T\;intensity,\;1.3{\times}10^7$ viable cells/ml of maximum cell density and 80 mg/l of maximum tPA production were obtained in batch cultivation, compared to $2.8{\times}10^6$ viable cells/ml and 59 mg tPA/1 in unexposed case (control). A similar trend was observed in the perfusion process, where it was possible to obtain $1.2{\times}10^7$ viable cells/ml of maximum cell density and 81 mg tPA/l of maximum tPA production by more than 80 days of cultivation. However, there was not much difference between $1{\mu}T\;and\;10{\mu}T$ in perfusion cultivation, possibly due to better environmental growth conditions being maintained by continuous feeding of fresh medium into the reactor. On the contrary, both cell growth and tPA production were severely inhibited at higher than 1 mT intensity, showing no growth at 10 mT exposure. Specific growth rate was linearly correlated to specific tPA production rate at $1{\mu}T$EMF intensity, which represents a partially growth-related relationship. It was also found that a large amount of $Ca^2+$ was released at low EMF intensity, even though the cell growth was not much affected. Low EMF intensity significantly improved both cell growth and tPA production, and tPA production seemed to be more affected than the cell growth, possibly due to the changes of cell membrane characteristics. It can be concluded that the elaboration of EMF intensity less than $10{\mu}T$ could improve cell growth and tPA production, but mainly tPA secretion through batch or perfusion process in a bioreactor.

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2009년도 추계학술발표대회
• /
• pp.26.2-26.2
• /
• 2009

A simple route of externalmechanical force is presented for enhancing the electrical properties ofpolymer nanocomposite consisted of nanowires. By dispersing ZnO nanowires inpolymer solution and drop casting on substrates, nanocomposite transistorscontaining ZnO nanowires are successfully fabricated. Even though the ZnOnanowires density is properly controlled for device fabrication, as-cast devicedoesn't show any detectablecurrents, because nanowires are separated far from each other with theinsulating polymer matrix intervening between them. Compared to the devicepressed at 300 kPa, the device pressed at 600 kPa currents increased by 50times showing the linear behavior against drain voltage and exhibits promisingelectrical properties, which operates in the depletion mode with highermobility and on-current. Such an improved device performance would be realizedby the contacts improvement and the increase of the number of electrical pathinduced by external force. This approach provides a viable solution for seriouscontact resistance problem of nanocomposite materials and promises for futuremanufacturing of high-performance devices.

• Journal of Chest Surgery
• /
• 제27권9호
• /
• pp.723-731
• /
• 1994

We have modified the isolated perfused working rabbit lung model [IPWL] by perfusing the isolated lung with a hollow fiber membrane deoxygenator.For assessment the stored lung was ventilated with FIO2 0.4 and perfused with 37$^{\circ}$C deoxygenated circulating blood at a rate 5ml/kg/min for several hours until lung failure.We chose to compare our developing solution which contained low potassium and pentastarch with the modified Euro-Collins solution .Experiments were divided into four groups[n=6] based on the type of flushing preservation solution and preservation time.The flushed lungs were then preserved into same solution at 8~10$^{\circ}$C with 100% O2 inflated condition for 1 or 20 hours.These following results were obtained.The IPWL model requires only one animal per experiment and allows for the continuous assessment of aerodynamic performance. This should therefore be used as screening test in lung preservation.One hour preservation groups, there were no significant difference in recovery rates of PaO2, PAP and Paw. Survival time in the one hour preservation groups were very significant long in the Group II[LPPS, p<0.01]. Twenty hours preservation groups, there were no significant difference in the recovery rates of PAP and Paw between Group III[m-ECS] and Group IV[NS], but PaO2 was significantly worse at onset of reperfusion in Group III when compared with Group IV [p<0.05]. And also survival time in the 20 hours preservation groups were significant long in the Group IV [p<0.05].

• 공업화학
• /
• 제2권4호
• /
• pp.411-420
• /
• 1991

$Pt-Sn/{\gamma}-Al/_2O_3$ 촉매에서 조촉매 주석의 함량을 달리하여 n-heptane을 반응물로 사용하여 탈수소 고리화 반응을 고정층 연속 흐름 반응기에서 행하였다. 조작 조건의 범위는 온도 $450-550^{\circ}C$, 압력 $20{\times}10^5-50{\times}10^5Pa$, 접촉 시간 0.09-0.27 hr, $H_2/H.C$. 몰비는 10이었다. 온도는 증가함에 따라 탈수소고리화반응의 전화율과 선택도가 증가했으며 압력의 증가에 대해서는 그 반대의 결과를 나타냈다. 조촉매 주석을 사용하였을 때 탈수소고리화반응의 선택도는 큰 변화를 보이지 않았지만 전화율이 증가했으며 이성화반응의 선택도는 커다란 증가를 보였다. 0.6 wt % Pt-0.6 wt % $Sn/{\gamma}-Al_2O_3$ 촉매에서 n-heptane의 탈수소 고리화 반응의 활성화에너지는 34.5 kcal/mole 이었다.

• 한국세라믹학회지
• /
• 제36권2호
• /
• pp.116-121
• /
• 1999

MgO 단결성 (100) 기판 위에 0.5 wt% Nb 첨가된 전기전도성의 SrTiO3 (Nb:STO) 박막을 Pulsed Laser Deposition 법으로 제조하였다. 산소압력, 타겟과 기판거리, 기판온도, 박막증착시간 등의 박막형성 조건을 다양하게 변화시켜 Nb:STO박막의 격자상수와 박막두께의 변화를 조사하였다. $700^{\circ}C$에서 제작한 0.5 wt% Nb doped SrTiO3 박막의 배향성은 산소분압변화에 따라(100), (110)과 (111)배향이 관찰되었고, 박막제조시의 산소분압이 79.8 Pa로 증가됨에 따라 격자상수는 감소하여 벌크값인 0.390 nm에 근접하였다. 증착시간증가에 따른 박막의 두께는 증착시간에 비례하여 증가하였고, 격자상수의 변화는 거의 없었다. 타겟과 기판사이의 거리가 멀어짐에 따라 박막의 두께는 감소하였으나, 격자상수에는 큰 변화가 없었고 박막두께분포의 균일성이 향상되었다.

• 한국수소및신에너지학회논문집
• /
• 제25권1호
• /
• pp.1-10
• /
• 2014

Ceria ($CeO_2$) was used to scavenge free radicals which attack the membrane in the polymer electrolyte membrane water electrolysis (PEMWE) circumstance and to increase the duration of the membrane. In order to improve the electrochemical, mechanical and electrocatalytic characteristics, engineering plastic of the sulfonated polyether ether ketone (SPEEK) as polymer matrix was prepared in the sulfonation reaction of polyether ether ketone (PEEK) and the organic-inorganic blended composite membranes were prepared by sol-gel casting method with loading the highly dispersed ceria and cesium-substituted phophomolybdic acid(Cs-MoPA) with cross-linking agent contents of 0.01mL. In conclusion, CL-SPEEK/$Cs_{(2.5)}$-MoPA/ceria(1%) membrane showed the optimum results such as 0.1095S/cm of proton conductivity at $80^{\circ}C$, 2.906meq./g-dry-membrane of ion exchange capacity and mechanical characteristics, and 49.73MPa of tensile strength which were better than Nafion 117 membrane.

• Tuberculosis and Respiratory Diseases
• /
• 제54권4호
• /
• pp.429-438
• /
• 2003

배 경 : 후기 ARDS로 스테로이드를 투여 받은 환자들에서 어느 시점까지의 반응의 유무가 기계환기에서의 이탈 여부를 예측할 수 있는지 시간경과에 따른 생리학적 지표의 변화를 기준으로 살펴보았다. 방 법 : 1999년 12월부터 2002년 7월까지 내과계 중환자실에서 ARDS로 7일 이상 기계환기치료를 받은 후에도 심한 저산소증($PaO_2/FIO_2$ ratio<200)이 지속되어 스테로이드 치료를 시행하였던 28명(남 : 여 24 : 4, 중앙연령 64세)을 대상으로 후향적 연구를 시행하였다. 스테로이드는 Meduri 등의 방법을 사용하여 투여하였다. 스테로이드 투여 후 기계환기에서 이탈이 가능하였던 환자들을 이탈군(n=14)으로, 기계환기 중 사망하였거나 이탈에 실패했던 환자들을 실패군(n=14)으로 나누어 기저특성과 기계환기 시작일(Dmv), 스테로이드 투여 3일전(D-3), 투여 당일(D0), 그리고 투여 후 3일(D3), 7일(D7)의 생리학적 지표들을 비교하였다. 결 과 : 이탈군과 실패군 사이의 기저특성상의 유의한 차이는 발견되지 않았으며 Dmv과 D-3에 두 군간에 생리학적 지표들의 차이는 없었다(p>0.05). D0에는 이탈군의 다장기부전 점수(SOFA score)가 6.6+/-2.5로 실패군의 8.8+/-2.9보다 유의하게 낮았다(p<0.05). 투여 D7에는 폐유순도를 제외한 대부분의 지표들이 두 군간 유의한 차이를 보였으며(p<0.05), 이탈군에서는 D0에 비해 생리학적 지표들이 유의한 호전이 있었던 반면에 실패군에서는 유의한 호전이 관찰되지 않았다. 결 론 : 결론적으로 후기 ARDS에서 스테로이드 투여 후 7일까지 생리학적 지표의 호전을 보이지 않는 경우 스테로이드 치료 지속 여부를 신중히 고려해야 할 것으로 생각한다.