정관복원술의 성공율에 영향을 미치는 인자

현재석 慶尙大學校 1997 論文集 Vol.36 No.-

Vasectomy reversal has become a common surgical procedure, utilizing either simple magnification or microsurgical technique. Patency rates reported by many investigators are high(over 90%), but reported pregnancy rates remain substantially low. To illustrate the different success rate of pregnancy and patency and to increase the pregnancy rate, I investigate the factors influencing the success rate of vasectomy reversal. For higher success rate of patency the surgeon should use the microscope. When the surgeon used the microscope, there were higher success rate in the striated vas portion anastomisis than convoluted vas. And for successful vasectomy reversal the most important factor was a meticulous and skillful anastomotic technique, although numerous other factors may influence the outcome. The success rate of pregnancy were higher in cases of short obstructed interval, good sperm motility in vas fluid, watery vas fluid, presence of sperm granuloma and low or absence of antisperm antibody. And there was no difference between the success rate of pregnancy by local nad general anesthesia.

디-젤 批塵用 移動벨트型 電氣集塵裝置의 小型化에 관한 硏究

文在德,孫鉉,서보혁,金光錫 경북대학교 공과대학 1984 工大硏究誌 Vol.13 No.-

A Moving-Belt Type Electrostatic Precipitator (MBEP) proposed by one of authers has been improved by introducing systematic control concept for the diesel soot particulates from diesel engine exhaust. The proto type MBEP was designed without helping of any precharger or precoagulator of the soot particles, and so it is too large for equipping to the vehicles. The improved one is designed as a systematic control device consisted of a precharger and a MBEP. This systematization makes it possible miniaturizing the size of MBEP without any drop of its collection performance by enhancing the corona field intensity and current density in the collection space concurrently obtained by reducing the interelectrode spacing of corona electrode to collection electrode. As a result, the collection efficiency of present MBEP system, which is reduced by ca. 1/2 in volume to the proto type MBEP, amounts to 82% at the gas velocity of 1.0m/s (this nearly equals to the gas exhaust of a 2000 cc diesel powered vehicle) and gas temperature of ca. 50℃ for the simulated soot particles ranged in size from 0.005μm (mass median diam is 1.0 μm). The collection efficiency of the improved MBEP system of 82% is higher enough to the US EPA regulation limit of 70% of the year of 1985 for the diesel powered light-duty trucks and passenger cars.

위성 ATM 망에서 ABR 서비스를 위한 트래픽 전송방식에 관한 연구

최병석,박재현,박현민,안현석,유재욱 동국대학교 산업기술연구원 1997 산업기술논문집 Vol.9 No.-

ATM의 ABR 서비스는 기본적으로 전달지연이 작은 지상망에 적합하게 개발되었기 때문에 위성 망과 같이 전달지연이 큰 상황에서는 망의 심각한 폭주나 링크의 채널 전송률 저하 등이 발생될 수 있다. 또한 위성채널은 지상 ATM 망에 비해 대역이 제한되어 있으므로 폭주를 미연에 방지하기 위해 보다 치밀하고, 지연에 덜 민감한 대역할당 알고리즘이 필요하다. 본 논문에서는 EPRCA 기반의 위성탑재 ATM 교환기로 구성된 위성 ATM 망에서 BECN과 큐의 상태정보를 이용하여 위성 ATM 망에서 ABR 서비스를 제공할 수 있는 방안을 제안하였다.

변압기의 유동대전에 대한 유속 및 유온의 영향에 관한 연구

정원용,고희석,박상현,박재윤,김정달 慶南大學校 附設 工業技術硏究所 1992 硏究論文集 Vol.10 No.-

本 硏究에서는 固體-液體 界面에서 液體가 流動할 때 발생되는 유동대전에 대한 硏究로서 大容量 變壓器내에서 絶緣油가 통과하는 通路를 모델링한 帶電 파이프를 設計·製作하고 대전 파이프내의 油路形狀에 따른 流動電流를 側定·分析하였다. 이러한 實驗으로부터 얻은 결과는 다음과 같다. 1) 流動電流는 油速의 增加에 따라 線形的으로 增加하였으며, 油溫의 增加에 따라 약 46[℃]이하에서는 增加하고 그 이상에서는 感少한다. 2) 絶緣油의 흐름이 원활하게 되도록 油路形狀을 변화시키면 流動電流는 感少한다. In this paper, the streaming electrification generated at a solid-liquid interface is studied. Electrification pipe modeled on the oil path of the high power transformer is designed and manufactured. The Streaming current is measured as a function of oil velosity, temperature at each electrification pipe. From the result of this study the following conclusions are obtained. 1) The streaming current increases linearly with increasing of oil velocity and It increases at lower temperature than 46[℃]and decreases at higher temperature than 46[℃] 2) The smoother the flow of insulating oil is the less the streaming current decreases.

Effect of Ambroxol on Secretion, Production and Gene Expression of Mucin from Cultured Airway Epithelial Cells

( Jae Woo Lee ),( Hyun Jae Lee ),( Choong Jae Lee ),( Su Yel Lee ),( Byeong Kyou Jeon ),( Heung Seog Bae ),( Kyoung Rai Cho ) 한국응용약물학회 2011 Biomolecules & Therapeutics(구 응용약물학회지) Vol.19 No.1

In this study, we investigated whether ambroxol significantly affects secretion, production and gene expression of mucin from cultured airway epithelial cells. Confluent primary rat tracheal surface epithelial (RTSE) cells were pretreated with adenosine triphosphate (ATP) for 5 min and then treated for 30 min with ambroxol to assess the effect on mucin secretion using ELISA. Additionally, confluent NCI-H292 cells were pretreated with ambroxol for 30 min and then stimulated with EGF or PMA for 24 h. The MUC5AC mucin gene expression and mucin protein production were measured by RT-PCR and ELISA. The results were as follows: (1) ambroxol did not significantly affect ATP-induced mucin secretion from cultured RTSE cells; (2) ambroxol inhibited the production of MUC5AC mucin protein induced by EGF and PMA in NCI-H292 cells; (3) ambroxol also inhibited the expression of MUC5AC mucin gene induced by EGF and PMA in NCI-H292 cells. This result suggests that ambroxol can inhibit the production and gene expression of MUC5AC mucin, by directly acting on human airway epithelial cells.

Hydrodeoxygenation of oleic acid over Ce<SUB>(1-x)</SUB>Zr<SUB>(x)</SUB>O<SUB>2</SUB> solid solution

Jae-Oh Shim,Dae-Woon Jeong,Won-Jun Jang,Kyung-Won Jeon,Won-Bi Han,Hyun-Suk Na,Hak-Min Kim,Hyun-Seog Roh,Jeong-Geol Na,You-Kwan Oh,Chang Hyun Ko,Sang Sub Han 한국신재생에너지학회 2013 한국신재생에너지학회 학술대회논문집 Vol.2013 No.05

Dentin sealing and antibacterial effects of silver-doped bioactive glass/mesoporous silica nanocomposite: an in vitro study

Jung, Jae-Hyun,Kim, Dong-Hyun,Yoo, Kyung-Hyeon,Yoon, Seog-Young,Kim, Yeon,Bae, Moon-Kyoung,Chung, Jin,Ko, Ching-Chang,Kwon, Yong Hoon,Kim, Yong-Il Springer-Verlag 2019 Clinical oral investigations Vol.23 No.1

천연 물질 Chrysophanic acid의 제초 활성

장현우(Hyun Woo Jang),서보람(Bo-Ram Seo),황현진(Hyun Jin Hwang),김재덕(Jae Deog Kim),김진석(Jin-Seog Kim),김성문(Songmun Kim),전재철(Jae Chul Chun),최정섭(Jung Sup Choi) 韓國雜草學會 2010 Weed&Turfgrass Science Vol.30 No.2

살초활성을 가지고 있는 것으로 알려진 천연 물질 chrysophanic acid에 대하여 온실조건 하에서 살초 특성을 조사하고, 다른 천연 제초활성 물질과의 합제 처리를 통한 살초 작용성 증진 평가를 통해 천연물 제초제로서의 개발 가능성을 확인하고자 일련의 실험을 수행하였다. Chrysophanic acid는 토양처리 살초 효과는 없었고 경엽처리 효과만 나타내었으며, 바랭이에 대한 생육시기별 살초력은 파종 7~14일에서 가장 우수하게 나타났다. 작물에 대한 약해는 토양처리에서는 나타나지 않았으나, 경엽처리에서는 아주 심하게 나타나 작물 선택성은 없었다. Caryophyllene oxide와의 합제처리에서는 고도의 상승효과가 발현되어 chrysophanic acid의 단점을 보완할 수 있는 이상적인 조합이었다. 이를 바탕으로 향후 2원 또는 3원 합제를 통한 보다 광범위하고 고활성의 천연 제초활성 물질을 발굴할 수 있는 기술 개발의 필요성이 제기되었다. 또한, chrysophanic acid는 광엽 및 화본과 초종에 관계없이 넓은 살초 스펙트럼을 갖고 있기 때문에 유효성분의 활성을 증가시킬 수 있는 제형기술 개발을 통해 고활성, 비선택성 천연물 제초제로서의 개발 가능성이 있을 것으로 생각되었다. Herbicidal characterisitcs of natural product chrysophanic acid were investigated in a greenhouse condition. At early- and middle-stage post-emergence treatments, several grasses and broadleaf weeds appeared to be very susceptible to chrysophanic acid. However, any significant herbicidal activity treated by pre-emergence did not occur at concentration ranges from 31.3 to 1,000 ug mL-1. Herbicidal activity of chrysophanic acid estimated by visual injury for large crabgrass was much higher when applied at 7 to 14 days after seeding than at 21 and 28 days after seeding. By post-emergence treatment, chrysophanic acid caused very considerable phytotoxicity on several grasses and broadleaf crops. In herbicidal interaction experiments determined by Colby"s method, the effect of chrysophanic acid and caryophyllene oxide tank-mixture showed very high synergistic activity. Although chrysophanic acid did not give any pre-emergence effect, herbicidal spectrum tended to be very wide and strong when treated by post-emergence. These results suggest that chrysophanic acid possesses a possible potential to develop as a natural herbicide.

One-pot size-controlled growth of graphene-encapsulated germanium nanocrystals

Lee, Jae-Hyun,Lee, Eun-Kyung,Kang, Seog-Gyun,Jung, Su-Ho,Son, Seok-Kyun,Nam, Woo Hyun,Kim, Tae-Hoon,Choi, Byong Lyong,Whang, Dongmok Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.440 No.-

<P><B>Abstract</B></P> <P>To realize graphene-encapsulated semiconductor nanocrystals (NCs), an additional graphene coating process, which causes shape destruction and chemical contamination, has so far been inevitable. We report herein one-pot growth of uniform graphene-germanium core–shell nanocrystals (Ge@G NCs) in gram scale by the addition of methane as a carbon source during the thermal pyrolysis of germane. The methane plays a critical role in the growth of the graphene shell, as well as in the determination of the nucleation density and diameter of the NCs, similar to a surfactant in the liquid-phase growth of monodisperse NCs. By adjusting the gas ratio of precursors, a mixture of germane and methane, we can control the size of the Ge@G NCs in the range of ∼5–180 nm. The Ge@G NCs were characterized by various microscopic and spectroscopic tools, which indicated that the Ge core is single crystalline, and is completely covered by the graphene shell. We further investigated the merits of the graphene shell, which can enhance the electrical conductivity of nanocrystalline materials.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The Ge-graphene core-shell nanocrystals (Ge@G NCs) are synthesized in gram scale. </LI> <LI> The role of CH<SUB>4</SUB> is critical for determination of the density and diameter of the NCs. </LI> <LI> The size of the Ge@G NCs can be controlled by tuning the gas ratio of GeH<SUB>4</SUB> and CH<SUB>4</SUB>. </LI> <LI> The graphene shell enhances the electrical conductivity of NCs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Petroleum like biodiesel production by catalytic decarboxylation of oleic acid over Pd/Ce-ZrO₂ under solvent-free condition

Shim, Jae-Oh,Jang, Won-Jun,Jeon, Kyung-Won,Lee, Da-We,Na, Hyun-Suk,Kim, Hak-Min,Lee, Yeol-Lim,Yoo, Seong-Yeun,Jeon, Byong-Hun,Roh, Hyun-Seog,Ko, Chang Hyun Elsevier 2018 Applied Catalysis A Vol.563 No.-

<P><B>Abstract</B></P> <P>The Ce/Zr ratio of Pd/Ce-ZrO<SUB>2</SUB> catalysts was systematically changed in order to investigate the effect of oxygen vacancy concentration on their decarboxylation activityunder solvent-free conditions for potential sustainable petroleum like biodiesel production. Pd/Ce<SUB>0.5</SUB>Zr<SUB>0.5</SUB>O<SUB>2</SUB> exhibited the highest catalytic activity from all other tested catalysts because it contained the highest oxygen vacancy concentration and Pd dispersion, as shown by the X-ray photoelectron spectroscopy, Raman spectroscopy, and CO-chemisorption data. A catalyst deactivation study also showed that both the Pd dispersion and the oxygen vacancy concentration influences the catalytic activity.The catalyst deactivation was found to occur mainly due to Pd sintering, decreases in the BET surface area and Pd dispersion, and partially due to the loss of oxygen vacancies.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Varying the Ce/Zr ratio effectively tunes the concentration of oxygen vacancies. </LI> <LI> High Pd dispersion and oxygen vacancy concentrations lead to enhanced activity. </LI> <LI> The catalyst deactivation was mainly caused by Pd sintering. </LI> <LI> Decarboxylation was found to be the main pathway in this reaction. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>