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증기응축용 직접접촉식 열교환기의 냉각수 유량과 내부압 변화에 따른 열전달 특성연구(LNG 기화기와의 조합목적)
이병철,한승탁,김종보,Lee, B.C.,Han, S.T.,Kim, C.B. 대한설비공학회 1991 설비공학 논문집 Vol.3 No.3
Heat transfer characteristics of a direct contact heat exchanger utilizing sieve trays and spray nozzles for steam condensation for the purpose of combining with a LNG evaporator have been investigated with various cooling water flow rates and different vacuum pressures within the heat exchanger for the purpose of steam condensation. Temperature profiles and the volumetric overall heat transfer coefficients in a direct contact heat exchanger have been obtained for comparisons. The results show that the temperature differences between cooling water and steam along the direct contact heat exchanger height are rapidly decreasing and the volumetric overall heat transfer coefficients of the exchanger improves greatly as the inside vacuum pressure increases. The values of the overall heat transfer coefficients at P=-680mmHg have been increased significantly compared with at atmospheric pressure. At given pressure conditions, it is found that the values of average volumetric overall heat transfer coefficients for the sieve tray are found to be approximately 10% higher than those of the spray nozzle.
직접접촉식 LNG기화기 응용을 위한 칼럼 열교환기 기포특성에 관한 연구
김성종,한승탁,김종보,Kim, S.J.,Han, S.T.,Kim, J.B. 대한설비공학회 1991 설비공학 논문집 Vol.3 No.2
In the present investigation, it has been proposed to utilize a direct contact heat exchanger as an evaporator to solve the difficulties such as scaling, corrosion and law thermal efficiencies, associated with the conventional evaporator. Liquified nitrozen was utilized as a working fluid to investigate basic natures of bubble dynamics in the evaporator, and spray nozzles were adopted to inject liquified nitrozen into the spray column with varying flow rates of dispersed phase fluids. Experimentations were carried out in the range of $6.54{\times}10^{-4}kg/s$ - 0.030 kg/s for dispersed phase flow rates with one, three and five nozzle holes. Observing the bubble dynamics for the evaporator the feasibility of utilizing a direct contact heat exchanger as a LNG evaporator has been evaluated. The results show that no eruption phenomena was observed in the present investigation with $LN_2$ and the interface between $N_2$ bubbles and water was fully turbulent. It is believed that the high injection velocity of $LN_2$ through the spray nozzles provide good mixing effects for both heat and mass transfers between water and $N_2$ bubbles. Ice was formed on the surface of the spray nozzle for higher $LN_2$ flow rates. However, even in this case, it is observed that the ice was detached as soon as it was formed. Under the present experimental conditions, the shapes of $LN_2$ bubbles were in the spherical-cap region according to the Clift, Grace and Weber Graphs. The height of foam region caused by the breakup of larger bubbles keeps increasing with high injection velocities until it reaches it's maximum height.
암성 골반통에 대한 경추간판적 상하복신경총 차단술의 효과
이윤우(Youn Woo Lee),윤덕미(Duck Mi Yoon),이기문(Gee Moon Lee),한승탁(Seung Tak Han),박혜진(Hae Jin Park) 대한통증학회 2000 The Korean Journal of Pain Vol.13 No.2
N/A Background: Superior hypogastric plexus block has been advocated as a useful technique for the treatment of cancer related pelvic pain. The aim of this study was to evaluate the effect of neurolytic trans-intervertebrodiscal superior hypogastric plexus block for pelvic cancer pain. Methods: Twenty-eight patients with gynecologic, colorectal or genitourinary cancer who suffered intractable pain were studied. We performed superior hypogastric plexus block by trans-intervertebrodiscal approach at L5/Sl level under the C-arm fluoroscopic guide unilaterally or bilaterally. Ten ml of 100% dehydrated alcohol was injected through each needle. We evaluated the change of visual analog pain score (VAS; 0~100 mm) and daily dose of oral morphine sulphate at the time of pre-block and 7 days after the block. Results: Fourteen patients (50%) had satisfactory pain relief (VAS<30) while five patients (18%) had moderate pain control (VAS 30-60). The remaining nine patients (32%) had mild or little pain relief (VAS >60) and their daily oral morphine doses were above 160 mg. Additional pain control method may be needed for those patients who received high dose of opioid before neurolytic block. Conclusions: We conclude trans-intervertebrodiscal neurolytic superior hypogastric plexus block was effective in relieving pelvic cancer pain. Neurolytic block, earlier stage, may provide better effects for more comfortable life at the end stage for cancer patients.
조새정(Cho Sae Jung),이혜민(Lee, Hye-Min),이민주(Lee, Min-Joo),이주헌(Lee Ju Heon),한승탁(Han, Seung-Tak),김진걸(Kim Jin Gul) 한국산학기술학회 2006 한국산학기술학회 학술대회 Vol.- No.-
Fe, Co, Zn, Cu, Pt 등의 전이금속과 ZSM-5 2종(SiO₂/Al₂O₃ 몰비: 23, 50)과 γ-alumina를 담체로 사용하여 촉매를 합성하였다. 합성방법은 CVD(화학기상증착법) 과 Dry Impregnation (건식함침법)방법이었다. CVD 방법으로 얻은 Fe/ZSM-5는 지지체로 사용된 ZSM-5의 SiO₂/Al₂O₃의 몰비가 작을수록, 즉 산점의 수가 많을수록 Fe 담지 량이 증가하는 것으로 보인다. 등온 환원 온도 400℃에서 수소 환원 양이 최대로 나타나며, 이는 보고되는 400℃에서의 최대 NOx 제거 반응 속도와 비례하는 것으로 나타난다.