Ca^(2+)―작동성 Cl^-전류에 미치는 이차 전령들의 효과

송인섭,이무열,방효원,엄대용,이상돈 중앙대학교 의과대학 의과학연구소 1993 中央醫大誌 Vol.18 No.3

The anion movements across the cell membrane were regarded as apart of passive distribution according to the cation movements. Recently, from the developement of patch clamp technique new concept for anion channels were introduced. And their roles in the genesis of action potential and resting potential were noticed. So we clarified the existence of the chloride channel in the smooth muscle cells and studied its nature in regard to the roles of the second messangers. We used the whold cell voltage clamp technique to study the current responses induced by carbachol application in the circular smooth muscle cells of the gastric antrum of the rabbit. The results were as follows; 1. Application of the carbachol induced the increase of inward currents in the hyperpolarized potential ranges, and the increase of outward currents in the depolarized ranges. 2. Even in the cases of blocking all the known currents, these current components were observed. 3. Sodium ion removel from the external medium rarely affected these current responses, and the addition of cadmium ion did not make any remarkable change. 4. Known second messangers such as c-AMP, c-GMP, heparin, A1F_4 rarely affected these current components. 5. Lowering of intracellular calcium ion concentration drastically reduced these current responses. Form the above results we can suggest that the carbachol induced current responses contained chloride currents which were activated by only intracellular calcium ion, not by any other second messegers in the gastric antral smooth muscle cells.

[논문]반응성 골재의 입자 크기와 입도가 모르타르의 알칼리-실리카 반응 팽창에 미치는 영향

전쌍순,이효민,진치섭 釜山大學校生産技術硏究所 2003 生産技術硏究所論文集 Vol.62 No.-

골재의 알칼리-실리카 반응성을 판정하는 방법으로 모르타르 바 법 (Mortar-Bar method) 이 일반적으로 사용되고 있다. 본 연구에서는 알칼리 골재 반응성을 판정하는 모르타르 바 법 중에서 촉진시험법인 ASTM C 1260 시험방법을 이용하여 반응성 골재를 판별하고l 판별된 반응성 골재의 입자 크기와 입도가 모르타르의 알칼리-실리카 반응 팽창에 미치는 영향에 관하여 검토하였다. 그 결과I 반응성 골재의 입자 크기 및 입도에 상관없이 반응성 골재의 총표면적이 커질수록 팽창률도 증대하여,알칼리-실리카 반웅에 의한 팽창과 반웅성 골재의 총표면적과의 사이에는 상관관계가 있는 것을 확인할 수 있었다.

[논문]재생골재의 광물학적 및 화학적 특성과 동결융해 저항성

전쌍순,이효민,진치섭 釜山大學校生産技術硏究所 2003 生産技術硏究所論文集 Vol.62 No.-

급속한 산업화와 인구증가 및 대량소비에 따른 페기물에 의하여 초래되는 지구 환경오염을 위한 사회시스템의 구축이 필요함을 암시한다고 볼 수 있다. 본 연구에서는 지금까지 주로 저급재료로 사용되던 재생골재의 구성광물,화학조성 및 물리화학적 특성과 알칼리-골재 반응성 여부를 조사하고, 재생굵은골재의 대체율에 따른 콘크리트 강도와 동결융해 저항성을 검토하여 재생골재의 재활용을 위한 기초자료를 제시하고자 한다. 본 연구에 사용된 재생골재는 천연골재에 비교하여 공학적 기초 물성치에서 현저히 큰 차이는 나타내지 않았으며, 이를 사용한 재생콘크리트의 공학적 특성도 보통 콘크리트의 기준에 근접하는 것으로 나타났다.

쇄석 골재의 광물학적 및 화학적 특성과 알칼리-실리카 반응성

전쌍순,박현재,이효민,진치섭 釜山大學校生産技術硏究所 2002 生産技術硏究所論文集 Vol.61 No.-

본 연구에서는 쇄석 골재의 광물학적 및 화학적 특징과 알칼리-실리카 반응에 대한 골재의 유해 가능성을 연구하였다. 이를 위하여 알칼리-실리카 반응을 유발하는 광물들의 포함여부 및 이에 따라 잠재적으로 조기 열화현상을 유발할 수 있는 암석을 유형별(화성암, 변성암, 퇴적암 및 탄산염암)로 골재를 수집하였다. 암종 별로 선별하여 수집한 골재 내의 알칼리 반응성 유해 물질 존재 여부 확인 X선 회절분석(XRD)과 편광현미경에 의한 광물학적 방법을 사용하였다. 알칼리-실리카 반응성 유무해 판단을 ASTM C 227의 Mortar-Bar 시험방법에 의해 평가 분석하였고, 주 화학성분은 X선 형광분석기(XRF)로 실시하였다. In Korea, due to the shortcomings of natural aggregates and increasing needs of crushed stones, it is necessary to examine the alkali-silica reaction of the crushed stones. The purpose of this study is to analyze petrographic, chemical properties and alkali-silica reaction of crushed stones. This study was performed to investigate the alkali-silica reaction of crushed stones using chemical analysis, physical properties, XRD, XRF and mortar-bar method. As a result, most of test aggregates didn't show any reaction, but many test aggregates have common deleterious mineral. Therefore, there exists the possibility of chemical reaction in petrographic point of view.

Prediction of Decompensation and Death in Advanced Chronic Liver Disease Using Deep Learning Analysis of Gadoxetic Acid-Enhanced MRI

Heo Subin,이승수,Kim So Yeon,Lim Young-Suk,Park Hyo Jung,Yoon Jee Seok,Suk Heung-Il,Sung Yu Sub,Park Bumwoo,Lee Ji Sung 대한영상의학회 2022 Korean Journal of Radiology Vol.23 No.12

Objective: This study aimed to evaluate the usefulness of quantitative indices obtained from deep learning analysis of gadoxetic acid-enhanced hepatobiliary phase (HBP) MRI and their longitudinal changes in predicting decompensation and death in patients with advanced chronic liver disease (ACLD). Materials and Methods: We included patients who underwent baseline and 1-year follow-up MRI from a prospective cohort that underwent gadoxetic acid-enhanced MRI for hepatocellular carcinoma surveillance between November 2011 and August 2012 at a tertiary medical center. Baseline liver condition was categorized as non-ACLD, compensated ACLD, and decompensated ACLD. The liver-to-spleen signal intensity ratio (LS-SIR) and liver-to-spleen volume ratio (LS-VR) were automatically measured on the HBP images using a deep learning algorithm, and their percentage changes at the 1-year follow-up (ΔLS-SIR and ΔLS-VR) were calculated. The associations of the MRI indices with hepatic decompensation and a composite endpoint of liver-related death or transplantation were evaluated using a competing risk analysis with multivariable Fine and Gray regression models, including baseline parameters alone and both baseline and follow-up parameters. Results: Our study included 280 patients (153 male; mean age ± standard deviation, 57 ± 7.95 years) with non-ACLD, compensated ACLD, and decompensated ACLD in 32, 186, and 62 patients, respectively. Patients were followed for 11–117 months (median, 104 months). In patients with compensated ACLD, baseline LS-SIR (sub-distribution hazard ratio [sHR], 0.81; p = 0.034) and LS-VR (sHR, 0.71; p = 0.01) were independently associated with hepatic decompensation. The ∆LS-VR (sHR, 0.54; p = 0.002) was predictive of hepatic decompensation after adjusting for baseline variables. ∆LS-VR was an independent predictor of liver-related death or transplantation in patients with compensated ACLD (sHR, 0.46; p = 0.026) and decompensated ACLD (sHR, 0.61; p = 0.023). Conclusion: MRI indices automatically derived from the deep learning analysis of gadoxetic acid-enhanced HBP MRI can be used as prognostic markers in patients with ACLD.

황-요오드 수소 제조 공정에서 초음파 조사를 이용한 분젠 반응의 특성

김효섭 ( Hyo Sub Kim ),이동희 ( Dong Hee Lee ),이종규 ( Jong Gyu Lee ),박주식 ( Chu Sik Park ),김영호 ( Young Ho Kim ) 한국공업화학회 2018 공업화학 Vol.29 No.1

황-요오드(SI) 공정의 통합 운전을 위한 분젠 반응 단계에서, I₂ 및 H₂O 반응물들은 HI_x 용액 내 용해된 성분들로써 공급된다. HI_x 용액과 SO₂ 공급을 이용하여 분젠 반응이 수행될 때 HI_x 상 내 대부분의 H₂SO₄ 생성물이 존재하며, 이에 따라 HI_x 상에 대한 H₂SO₄ 상의 부피 비가 매우 낮다. 본 연구에서 우리는 상 분리 성능을 향상시키기 위해 HI_x용액을 이용한 분젠 반응에 대한 초음파 조사의 효과들을 연구하였다. 분젠 반응과 함께 초음파가 조사될 때 HI_x 상으로부터 H₂SO₄ 상으로 이동된 H₂SO₄의 양은 최대 58.0 mol%까지 증가하였으며, H₂SO₄ 상의 부피 또한 최대 13.1 vol%까지 증가하였다. 특히, 상 분리에 대한 초음파 조사의 효과는 온도, I₂ 및 H₂O 공급 농도가 감소함에 따라 향상되었다. 초음파 조사는 HI_x 상 내 반응 평형을 미시적으로 이동시킴으로써 추가적인 H₂O 분자들의 형성을 유도하였다. 이로부터 추가적으로 생성된 H₂O 및 분리된 H₂SO₄ 분자들이 H₂SO₄ 상으로 이동할 수 있는 더 많은 H₂SO₄·xH₂O (x = 5-6) 착물들을 형성하였다. In Bunsen reaction section for the integrated operation of sulfur-iodine (SI) process, I₂ and H₂O reactants are supplied as dissolved species in an HI_x solution. Most of the H₂SO₄ product is found in the HI_x phase when Bunsen reaction is performed using the HI_x solution and SO₂ feed, so that the volume ratio of the H₂SO₄ phase to the HI_x phase is very low. In this study, we investigated the effects of ultrasound irradiation on Bunsen reaction using the HI_x solution to improve its phase separation performance. With ultrasound irradiation, the amount of H₂SO₄ moved to the H₂SO₄ phase from the HI_x phase increased by up to 58.0 mol% and the volume of H₂SO₄ phase also increased by up to 13.1 vol%. In particular, the effect of ultrasound irradiation on the phase separation was improved with decreasing operating temperature, I₂ and H₂O feed concentrations. The ultrasound irradiation induces the formation of additional H₂O molecules by shifting microscopically the reaction equilibrium in the HI_x phase. Afterward, the additionally generated H₂O and isolated H₂SO₄ molecules form more H₂SO₄·xH₂O (x = 5-6) clusters that can be moved to the H₂SO₄ phase.

EFDC를 이용한 아산만 연안의 해수유동 및 수온 모의

이효동 ( Hyo-dong Lee ),안태진 ( Tae-jin Ahn ),김경섭 ( Kyung-sub Kim ) 한국환경기술학회 2015 한국환경기술학회지 Vol.16 No.6

본 연구는 강, 호수, 하구 및 해역 등 다양한 수계에 널리 이용 가능한 EFDC(Environmental Fluid Dynamic Code) 모델을 이용하여 아산만의 조위, 유속분포 등 해수유동과 수온에 관하여 모의하고 실측치와 비교·분석하였다. EFDC 모델 적용을 위해 SMS 프로그램을 사용하여 격자망을 구성하였으며 격자의 길이는 161.1 m에서 960.9 m이며 격자의 총 개수는 1,872이다. 경계 조건은 안성천 및 삽교천이 유입하는 아산호 및 삽교호 방조제 방류량과 화옹 방조제 인근 해역에 해당하는 아산 05지점의 4대 분조(M₂, S₂, K₁, O₁) 자료를 적용하였다. 모의 결과 아산만은 북·서 방향으로 개방된 형태를 나타내는 해역에 접해있어 개방경계구역에 의한 민감도가 크며 상대적으로 아산호 및 삽교호에 의한 영향은 미미한 것으로 평가되었다. 조위 평균제곱근오차는 0.4769 m로 나타났으며, 유속도 실측치와 모의치 차이가 크지 않아 재현성이 높은 것으로 파악되었다. 수온 평균제곱근오차는 1.199℃로 나타나 4계절 재현성이 우수한 것으로 분석되었다. 격자의 해상도 향상을 통하여 실제 해저지형에 가까운 모델을 구축하면 재현성이 높은 해수유동 및 오염물질 모의가 가능할 것으로 판단한다. EFDC(Environmental Fluid Dynamic Code) model which is widely used in river, lake, estuary and ocean was applied to Asan Bay to calculate tidal level, current flow and water temperature in this study and the measured values were compared and analyzed with the running results of this model. Grid system for EFDC model was developed by SMS program and the length of grid was 161.1 m through 960.9 m and the total number of grids was 1,872. Discharge flow rates from embankments of Asan and Sapgyo Lakes and four major tides(M₂, S₂, K₁, O₁) at Asan 05 site near Hwaong embankment were considered as boundary conditions. Simulation results revealed that the open boundary conditions where located in the north-west direction of Asan Bay are more sensitive than the boundary of Asan and Sapgyo Lakes. Root mean square errors(RMSE) of tidal level showed 0.4769 m and the recurrence of running results is a little high because the simulated current flow velocities followed the measured values. Water temperature for four seasons were well estimated since RMSE becomes 1.199℃. The model with fine grid system reflecting real geographical features of tidal area will guarantee improving tidal current and contaminants movement.

A convenient method for phase separation and composition determination of the Bunsen reaction products in sulfur-iodine hydrogen production process

Kim, Hyo Sub,Park, Hyun Kyu,Kim, Young Ho,Lee, Jong Gyu,Park, Chu Sik,Bae, Ki Kwang Elsevier 2017 International journal of hydrogen energy Vol.42 No.7

<P><B>Abstract</B></P> <P>During the integrated operation of the sulfur-iodine process, it is important to conveniently and quickly measure the composition of the Bunsen reaction products and to ascertain the location of each phase in the liquid–liquid phase separator. First, the method to determine each composition in HI<SUB>x</SUB> phase system which contains four components of HI, I<SUB>2</SUB>, H<SUB>2</SUB>O, and H<SUB>2</SUB>SO<SUB>4</SUB> was newly proposed using only the data of H<SUP>+</SUP> and I<SUP>−</SUP> contents and the density of the HI<SUB>x</SUB> phase. This method has the advantage to replace the complicated and time-consuming traditional titration step of I<SUB>2</SUB>. The calculated I<SUB>2</SUB>/HI molar ratios were within an error of ±5% at all temperature conditions, indicating that this method was suitable for I<SUB>2</SUB> composition analysis. Meanwhile, the use of an electrical conductivity sensor was discussed as a sensing technology during the phase separation of Bunsen reaction products. The electrical conductivity was measured using different compositions of the Bunsen reaction products. The conductivity difference between H<SUB>2</SUB>SO<SUB>4</SUB> and HI<SUB>x</SUB> phase solutions was approximately 478–822 mS/cm in the main compositional range of the Bunsen reaction products. Therefore, this method can replace the traditional phase separation method using a DP (differential pressure) cell.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The convenient determination method of the product composition was proposed. </LI> <LI> The I<SUB>2</SUB>/HI molar ratios calculated by the new method were within an error of ±5%. </LI> <LI> The use of an electrical conductivity sensor was discussed as a sensing technology. </LI> <LI> The electrical conductivity sensor can replace the traditional phase separation method. </LI> <LI> The schematic diagram of a liquid–liquid phase separator was proposed. </LI> </UL> </P>

Structure-tunable synthesis of titanate nanotube thin films via a simple hydrothermal process

Guo, Yupeng,Lee, Nam-Hee,Oh, Hyo-Jin,Yoon, Cho-Rong,Park, Kyeong-Soon,Lee, Hee-Gyoun,Lee, Kyung-Sub,Kim, Sun-Jae IOP Pub 2007 Nanotechnology Vol.18 No.29

<P>In this study, titanium metal acts as the titanium source to prepare oriented titanate nanotube thin film. The effects of preparation parameters, such as reaction temperature, duration and post-treatment conditions, on the film morphology and stability have been examined. A general formation mechanism for oriented titanate nanotube thin film is proposed on the basis of detailed observations of the products using two-dimensional surface SEM studies and TEM images. The overall formation of titanate nanotubes can be summarized as a sequence of four steps: (a)?titanium dissolution and alkali titanate hydrogel formation; (b)?alkali titanate hydrogel dissolution, increased TiO<SUB>3</SUB><SUP>2−</SUP>, TiO<SUB>2</SUB>(OH)<SUB>2</SUB><SUP>2−</SUP> or Ti<SUB><I>n</I></SUB>O<SUB>2<I>n</I>+<I>m</I></SUB><SUP>2<I>m</I>−</SUP> concentration and layered Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> formation; (c)?layered Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> growth; (d)?nanotube formation via Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> splitting and the multilayer scrolling process. The Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> lamellar structures split between the (010) planes into nanosheets. </P>

W₃₅Fe₄₃C₂₂비정질 합금분말의 결정화 거동

권영준 ( Young Jun Kwon ),유정선 ( Jung Sun Yoo ),박수근 ( Soo Keun Park ),이근효 ( Keun Hyo Lee ),조기섭 ( Ki Sub Cho ) 한국열처리공학회 2018 熱處理工學會誌 Vol.31 No.4

W, Fe, and carbon powders were mechanical alloyed to produce W₃₅Fe₄₃C₂₂ ternary alloy powders containing nanocrystal W embedded within amorphous matrix. When the powder samples were heated to the primary crystallization temperature of 735℃, most parts of their amorphous region were fully crystallized to [W,Fe]- rich M₆C carbides. Interestingly, a little portion of the carbides changes to stoichiometric line compounds (M₁₂C and W₆Fe₇) and a solution phase (Fe-rich bcc), and remaining parts of the crystallites were amorphized again. The resulting microstructure was retained even by cyclic heating between room temperature of 1,200oC, and thus we found that the amorphous structure can be irreversibly formed at above glass transition temperature. (Received June 11, 2018; Revised June 25, 2018; Accepted July 3, 2018)