• Journal of Life Science
• /
• v.25 no.9
• /
• pp.1036-1042
• /
• 2015

By using effective sanitizers, early block for transmission of pathogens is the effective way to prevent epidermic outbreaks. Here we developed a chlorine oxide bubbling type of sanitizing tablets and evaluated the disinfectant and sanitization effects. The sanitizers showed 99.999% of sanitization effect for Escherichia coli ATCC 10536 and Staphylococcus aureus ATCC 6538 strains for 5 min±10 sec on 20±1℃ in clean condition by dilution-neutralization method. It reduced more than 5 log₁₀ cfu/ml of a legal permission standard of colony reduction. When a few used socks and underwear soaked for one hour in the 0.1% of the sanitizing tablets, no microorganisms were grown on CHROMagar plates. However, on CHROMagar plates of the no sanitizing tablets treated control, about 6.5×10⁴ cfu/ml of Staphylococcus sp., Klebsiella sp. and Enterococus sp. were grown. Furthermore, the sanitizing tablets killed approximately 1.5x10⁸ cfu/ml of E. coli BL21 in 5 minutes. Therefore, we concluded that the chlorine based bubbling type of sanitizing tablets satisfied the legal standard for the regulation of food and drug safety for disinfectants and sanitizers to pathogens and daily supplies.

• Electrical & Electronic Materials
• /
• v.4 no.2
• /
• pp.114-122
• /
• 1991

본 논문에서는 최근의 고온초전도체 재료의 개발에 주목하여 액체 질소의 절연파괴특성에 전극이 미치는 영향에 관하여 연구하였다. 액체 질소의 극성효ㅗ가는 액체 헤리움과는 달리 전극간 거리에 따라 다르며 단 간격에서의 파괴정압은 평등전계가 가장 높고, 정침, 부침의 순서이며 장 간격에서는 역전한다. 그리고 conditioning효과, 불순물효과, 피복효과, 압력의존성 등의 실험으로 부터 액체 질소의 파괴기구는 정침에서는 정 스트리머, 부침에서는 기포파괴의 가능성이 높은 것으로 생각된다. 또한 극저온 절연 설계에서는 전극을 절연물로 피복하고 고순도 액체 질소보다는 불순물이 혼입된 액체 질소, 즉 상용 액체 질소를 냉각 및 절연재료로 사용하면 유리하다.

• Journal of Chest Surgery
• /
• v.34 no.8
• /
• pp.621-625
• /
• 2001

For many years, 10mm videothoracoscope has been widely used in bullectomy of primary spontaneous pneumothorax. However we used a 2mm videothoracoscope to minimize operative wound. Thus, we compared the clinical results of bulllectomy using 2mm videothoracoscope with bullectomy using 10mm videothoracoscope. Material and method: We analyzed 118 patients who underwent VATS for primary spontaneous pneumothorax from April, 1998 to December, 2000. 2mm videothoracoscope was used in 53 patients(Group A) and 10mm videothoracoscope was used in 65 patients(Group B). The mean age was 20.2$\pm$6.9 years old in group A and 20.1$\pm$6.1 years old in group B. The mean follow up was 10.9$\pm$3.8 months in group A and 11.4$\pm$4.3 months in group B. Result: The operation time was shorter in group A than group B(55.7$\pm$22.9 minutes, 71.2$\pm$21.4 minutes, p<0.05). The duration of postoperative hospital stay was shorter in group A than group B(7.2$\pm$3.2 days, 9.2$\pm$3.6 days, p<0.05). The duration of postoperative chest tube indwelling was shorter in group A than group B(4.7$\pm$3.1 days, 6.3$\pm$2.8 days, p<0.05). The duration of postoperative air leakage(0.6$\pm$2.1 days, 1.0$\pm$2.4 days, p>0.05), the amount of analgesics(1.38$\pm$1.0 ampules, 1.7$\pm$1.4 ampules, p>0.05), the amount of analgesics(1.38$\pm$1.0 ampules, 1.7$\pm$1.4 ampules, p>0.05), postperative complications(2 cases, 7cases, p>0.05) and recurrences(1 case, 1 case, p>0.05) were not statistically different between two groups. Operative wound was smaller in group A than B. Conclusion: There were non adverse results in group A than group B. Furthermore, bullectomy using 2mm videothoracoscope brought us minimized operative wound and good cosmetic results. Thus, we could recommend bullectomy using 2mm videothoracoscope in primary spontaneous penumothorax.

• Cement Symposium
• /
• no.17
• /
• pp.15-21
• /
• 1989

시멘트 모르타르에 EVAc 에멀젼 및 계면활성제(Sodium Dodecylbenzenesulfonate)를 첨가하여 압축강도, 흡수율, 화학적 저항성, 수화발열속도, 전자현미경 등으로 그 물성을 관찰하였다. EVAc를 시멘트에 첨가할 경우 5-15wt$\%$, SDBF는 0.03wt$\%$를 첨가하고 혼수량을 flow value로써 기준하는 것이 최적조검임을 알 수 있었다. 그리고 EVAc emulsion을 첨가함으로써 혼수량 및 흡수율의 감소 효과를 거둘 수가 있었으며 또한 화학적 저항성도 증가되었다. EVAc emulsion을 과다 첨가할 경우에는 기포가 많이 형성되어 강도가 저하하나, 여기에 계면활성제(Sodium Dodecylbenzenesulfonate)를 가하면 강도가 증가하였으며, 한편 수화 속도는 지연되었다.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.11a
• /
• pp.905-908
• /
• 2006

In this study examines physical and mechanical properties the use of domestic low grade meta-kaolin in light weight porous concrete. For this purpose light weight porous concrete incorporating low grade meta-kaolin admixture, was tested for tensile strength and acoustic characteristics. Checking tensile strength of cement and low grade meta-kaolin mixture was used to determine the optimum mix proportion of the low grade meta-kaolin admixture. In this paper sound absorbing material has been investigated by using the light weight porous concrete.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 1997.10a
• /
• pp.63-66
• /
• 1997

본 논문은 초전도 및 극저온 케이블의 냉매와 전기절연으로 사용되고 있는 액체질소의 연면방전특성에 관하여 연구하였다. 기포효과를 고려하여 대기압하에서의 정극성 및 부극성 직류고전압을 사용하였고, 연면방전시 방사되는 방사전자파의 스펙트럼 분포 특성을 관측하였다.

• Applied Chemistry for Engineering
• /
• v.4 no.2
• /
• pp.358-364
• /
• 1993

Low foaming scouring agents(SLFS) were prepared by blending of 2-ethylhexylaminoethyl sulfate, Na-dioctyl sulfosuccinate, Newpol PP-2000, MJU-100, ethylene glycol and organic solvent. As the results of several tests, SLFS-2 showed good scouring effect, penetrating ability, emulsifiability and anti-alkaline property, and showed not much water pollution. The foaming power of SLFS-2 measured by Ross & Mites method was 8mm foam height immediately after foaming. And the foaming power of SLFS-2 measured by Ross & Clark method were less than 300mm foam height at $30^{\circ}C$, and 15mm at $80^{\circ}C$. As a result, SLFS-2 was proved as a good low foaming scouring agent.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.12 no.11
• /
• pp.963-971
• /
• 2000

In order to investigate the effects of an electric field on EHD(Electro-hydrodynamic) nucleate boiling hat transfer characteristics in a nonuniform electric field under saturated pool boiling, the basic study has been performed experimentally. In the present study, the working fluid is R-113 and the plate-wire electrode system is used to generate a steep electric field gradient. Boiling parameters are investigated by using a high speed camera. The electric field distribution around a wire is obtained to understand the effect of an electric field on bubble departure/movement. The experimental results show EHD effects are much more considerable when the applied voltage increases. Bubbles depart away from the heated wire in radial direction. It is confirmed that the mechanisms of EHD nucleate boiling are closely connected with the dynamic behavior of bubbles. The boiling parameters are significantly changed by the electric field strength. With increasing applied voltages, the bubble size decreases and the nucleation site density, bubble velocity and bubble frequency increase.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2012.05a
• /
• pp.491-493
• /
• 2012

우리나라는 농업용수, 생활용수 등의 목적으로 여러 개의 호소 등을 설치하여 운영 중에 있다. 하지만 몇몇 호소들은 인구증가 및 산업발달로 인하여 매년 오염도가 증가하는 것으로 알려져 있으며, 특히 부영양화 현상으로 인하여 남조류가 과다번식 할 경우 호소 수질 및 수생태계에 악영향은 미치는 것으로 알려져 있다. 따라서 호소의 부영양화 현상을 제어하기 위한 많은 연구가 이루어지고 있으며, 부영양화 현상을 발생시킬 수 있는 여러 제한인자 중 인(P)에 대한 관심이 많아지고 있는 실정이다. 부상분리의 일종인 DAF는 침전공정의 대안으로서 25년 전부터 유럽과 미국을 중심으로 정수 및 하수처리 공정에서 이용되어 왔다. 가압부상공법에서 발생되는 기포의 크기는 $50{\sim}100{\mu}m$ 정도로 부상물질인 스컴이 파괴될 가능성이 낮고 기포의 크기가 작아 공기의 용해효율이 높으며 대전작용, 물리적 흡착효과 등의 특징을 가진다고 알려져 있다. 또한 공기와 물 뿐만 아니라 Al 성분의 응집제인 PAC를 이용하여 버블을 발생시킬 경우 인의 제거 효율이 크다고 알려져 있다. 가압부상공법의 경우 응집 침전 공정과는 달리 발생되는 처리과정에서 발생되는 부산물을 외부로 유출 시킬 수 있기 때문에 호소 수질정화에 이용될 수 있다고 판단된다. 따라서 본 연구에서는 저수지의 형태와 유사한 반응조를 설계하여 DAF를 주입하는 실내실험을 진행하였으며, 이를 통해 호소수질 정화를 위한 DAF의 타당성에 대해 평가하기 위해 이루어졌다.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.21 no.7
• /
• pp.77-83
• /
• 2022

When carbon dioxide in a liquid becomes supersaturated, carbon dioxide gas bubbles are generated in the liquid, and they ascend to the surface as they develop further. At this time, the inner wall of the cup with carbon gas attached is known as the entrapped gas cavity (EGS); once an EGS is established, it does not disappear and will continuously create carbon bubbles. This bubbling phenomenon can be activated or suppressed by changing the properties of the solid surface in contact with the carbonated liquid. In this study, the foaming of carbonated liquid is promoted or suppressed by modifying the wettability of the surface. A micro/nano surface structure is formed on the surface of an aluminum cup to produce a superhydrophilic surface, and a superhydrophobic surface similar to a lotus leaf is synthesized via fluorination. Experiment results show that the amount of carbon dioxide bubble generated differs significantly in the first few seconds depending on the surface, and that the amount of gas generated after it enters the stabilization period is the same regardless of the wettability of the cup surface.