1 , 3-디옥산을 함유한 분해성 계면활성제의 합성의 및 계면 특성

김치회,노윤찬,김유옥,남기대 ( Chi Hoi Kim,Yun Chan Roh,Yu Ok Kim,Kie Dae Nam,C . H . Kim,Y . C . Roh,Y . O . Kim,K . D . Nam ) 한국유화학회 1996 한국응용과학기술학회지 Vol.13 No.3

In acid-catalyzed acetal cyclization of long aliphatic aldehydes(R=n-C_7H_15 ; n-C_9H_19 ; n-C_11H_23) with 1,1,1-tris(hydroxymethyl)propane, 2-alkyl-5-(sulfonatedpropylethermethyl)-5-ethyl-1, 3-propanesultion in the presence of sodium hydride. These compounds were a new group of destructible surfactants which were readily hydrolyzed and oxidized in natural water reservoirs. Physical properties of these new compounds involved some surface properties such as Krafft point(Kp), critical micelle concentration(cmc), surface tension of aqueous solutions near cmc(γ_min), foaming power, emulsion power and hydrolysis properties were determined. The destructible surfactants containing 1,3-dioxane ring were synthesized to about 85±5.5% yield. The cmc values of the compounds by ring method were assumed to 0.5∼5.0×10 exp(-3) mol/L range and surface tensions at cmc 29.5∼33.0dyne/cm respectively at 25℃. The foaming power and foam stability were 170∼230mm and 52∼135mm respectively at 1×10 exp(-2) mol/L, foam was occurred rarely below 1×10 exp(-3) mol/L. The emulsion property of liquid paraffin was better than that of soybean oil. For hydrolysis property with ph and time, these compounds were decomposed within about 200minutes at ph1∼2. Hopefully these compounds are expected to be a good O/W emulsifier that have decomposability in acid and may be used in the process which do not need foaming.

말기신부전 환자에서 혈액투석 전후의 QT간격분산 비교

강대웅,정지용,윤나라,안치용,김종오,신병철,정종훈,김현리 朝鮮大學校 附設 醫學硏究所 2006 The Medical Journal of Chosun University Vol.31 No.2

Background: Some cases of QT interval, corrected QT interval (QTc), QT dispersion (QTd) and corrected QT dispersion (QTcd) have been reported in ESRD, but these results are variable and the influence of a hemodialysis is still controversial, In this study, we investigated the effect of hemodialysis on QT and QTc interval and QT and QTc dispersion in patients with ESRD 15 min before and 15 minute after each hemodialysis. Methods: Sixty-seven patients with ESRD (men 33 & women 34) on three-times stable hemodialysis (>3 months) were randomly enrolled. Fifty control subjects with a similar age and normal renal function were enrolled from this hospital. Routine biochemical studies were measured pre- and post dialysis, at the time of the ECG. Plasma Na+, K+, BUN, creatinine, ionized calcium and phosphate were checked. Twelve-lead electrocardiographs were performed at 10㎜/mv and 50㎜/s using a HewIett-Packard Pagewriter 100, before and after a single hemodialysis session.The QT interval was measured from the onset of the QRS complex to the end of the T wave. If the end of the T wave was not clear in a particular lead then it was excluded from analysis. When U waves were present, the end of the T wave was taken as the nadir between the T and U waves. Each QT interval was corrected for heart rate using Bazett's formula (QTc==QT/√(RR)) (ms). The difference between maximal and minimal QT interval duration was defined as QT dispersion (QTd) in each of the 12 leads. Result: This study demonstrates that QT, QTd, QTcd is higher in hemodialysis patients compared with control subjects, and QT and QTd rise postdialysis to levels comparable to those seen acutely following myocardial infarction, when patients are at greatly increased risk of potentially fatal ventricular arrhythmias, Conclusions: QT interval and QT dispersion, markers of risk for arrhythmias and sudden death, are elevated in hemodialysis patients, and rise postdialysis. QT interval and QT dispersion is an easily obtainable, noninvasive, simple, inexpensive, and widely available method of risk stratification in uremic patients receiving chronic dialysis. Additional studies are needed to clarity whether increased postdialysis QT dispersion results in an increased occurrence of arrhythmias.

Galen정맥의 진성 뇌동맥류 기형 : Case Report

배장호,고삼규,김오룡,김선용,지용철,최병연,조수호 대한신경외과학회 1990 Journal of Korean neurosurgical society Vol.19 No.6

A 27-year-old male was suffered from seizure due to Galenic aneurysmal malformation which was mainly fed by thalamoperforating circumferential(P2) and posterior cerebral artery(P4) and drained through basal vein of Rosenthal because of agenesis of straight sinus. The aneurysmal dilatation was successfully extirpated by excision of feeding arteries and draining veins including inferior sagittal sinus and straight sinus. We report a case of true aneurysmal malformation of vein of Galen.

Metal-Insulator Transition Induced by Short Range Magnetic Ordering in Mono-layered Manganite

Chi, E.O.,Kim, W.S.,Hong, C.S.,Hur, N.H.,Choi, Y.N. Korean Chemical Society 2003 Bulletin of the Korean Chemical Society Vol.24 No.5

The structural, magnetic, and transport properties of a mono-layered manganite $La_{0.7}Sr_{1.3}MnO_{4+{\delta}}$ were investigated using variable temperature neutron powder diffraction as well as magnetization and transport measurements. The compound adopts the tetragonal I4/mmm symmetry and exhibits no magnetic reflection in the temperature region of 10 K ≤ T ≤ 300 K. A weak ferromagnetic (FM) transition occurs about 130 K, which almost coincides with the onset of a metal-insulator (M-I) transition. Extra oxygen that occupies the interstitial site between the [(La,Sr)O] layers makes the spacing between the [MnO₂] layers shorten, which enhances the inter-layer coupling and eventually leads to the M-I transition. We also found negative magneto resistance (MR) below the M-I transition temperature, which can be understood on the basis of the percolative transport via FM metallic domains in the antiferromagnetic (AFM) insulating matrix.

Towards nano-waveguides

Chi-O Cho,Young-Geun Roh,Yeonsang Park,Jae-Soong I,전헌수,Beom-Seok Lee,Hye-Won Kim,Young-Ho Choe,Mingyu Sung 한국물리학회 2004 Current Applied Physics Vol.4 No.2-4

We propose a hybrid type of photonic crystal waveguide (PCW) structure, in which two-dimensional (2D) PCW is embedded in atwo one-dimensional (1D) PCW. This rather new PCW structure should be identical to a full three-dimensional PCW in itsfunctionality, but its fabrication is much simpler. Toward the realization of such an amenable PCW structure, an epitaxially grownGaAs/AlAs multilayer structure was successfully converted to an omnidirectional reector, suitable for the 1D photonic crystalstructure in the hybrid PCW. In terms of fabricating 2D-PCWs, we took a rather new approach instead of conventional electron-beam lithography. An air-bridge type of thin lm Si 2D-PCW was fabricated using a combined technique of holography andphotolithography. Optical characterizations revealed that the propagation loss of the waveguide fabricated such is comparable tothose of e-beam generating PCWs in the literature.

현장에서 본 한국 교육제도의 문제점

오치규 ( Chi Kyu O ) 한국정치평론학회 2010 정치와 평론 Vol.7 No.-

This article deals with some serious problems common to the educational policies of the successive governments in Korea, especially, since 1998. Most of all, their policy aims had effects opposite to their presumed expectations. It was largely owing to policy directors` disregard to the concrete circumstances which surrounded education, that is, their lack of experience. For example, the measures to reduce expenditure on the private sector of education sapped the public education, making students more dependent upon the private-supplied education. The present educational policies have suffered a similar failure. The chief causes are (1) trying to screen the stubborn fact of competition, making a deceptive surface of non-competition, (2) the too-frequent reformations of educational courses and tests, (3) the difficult forms of test in the SAT, (4) the disability of public schools to meet urgent matters of education. Without consideration of these concrete circumstances, every policy would end up in the same failure. I argue that the proper remedy for these inconveniences consists in recovery of ``lived experience`` in the making of policies.

Metal-Insulator Transition Induced by Short Range MagneticOrdering in Mono-layered Manganite

E.O.Chi 대한화학회 2003 Bulletin of the Korean Chemical Society Vol.24 No.5

중성자 조사 및 열처리에 따른 SA508 Cl.3강의 자기특성 변화

장기옥(K. O. Chang),김택수(T. S. Kim),심철무(C. M. Sim),지세환(S. H. Chi),김종오(C. O. Kim) 한국자기학회 1998 韓國磁氣學會誌 Vol.8 No.5

In relation to the application of magnetic method to the evaluation of irradiation damage (embrittlement) changes in the magnetic parameters(hysteresis loop and Barkhausen noise) and Vickers microhardness due to neutron irradiation and heat treatment were measured and compared. In the case of irradiation (2.3×10^(19) n/㎠, E≥1 Mev, 288 ℃) hysteresis loop measurements show that susceptibility decreases as coercivity increases. Saturation magnetization do not show any change. Barkhausen noise amplitude and Barkhausen noise energy have decreased while Vickers microhardness has increased. For isothermally heat treated condition of irradiated specimen at 470 ℃ and 540 ℃, Barkhausen noise energy has increased while Vickers microhardness has decreased. Results of BNE and Vickers microhardness are reversed to the results on irradiated condition. All these consistent changes in magnetic parameter and Vickers microhardness measurement, which are thought to be resulted from the interaction between irradiationinduced defects and dislocation, and magnetic domain, respectively, show a possibility that magnetic measurement may be used to the evaluation of material degradation and recovery due to neutron irradiation and heat treatment, respectively, if a relevent large database in prepared.

The Amazon Tall Tower Observatory (ATTO): overview of pilot measurements on ecosystem ecology, meteorology, trace gases, and aerosols

Andreae, M. O.,Acevedo, O. C.,Araù,jo, A.,Artaxo, P.,Barbosa, C. G. G.,Barbosa, H. M. J.,Brito, J.,Carbone, S.,Chi, X.,Cintra, B. B. L.,da Silva, N. F.,Dias, N. L.,Dias-Jú,nior, C. Q.,Dita Copernicus GmbH 2015 Atmospheric Chemistry and Physics Vol.15 No.18

<P>Abstract. The Amazon Basin plays key roles in the carbon and water cycles, climate change, atmospheric chemistry, and biodiversity. It has already been changed significantly by human activities, and more pervasive change is expected to occur in the coming decades. It is therefore essential to establish long-term measurement sites that provide a baseline record of present-day climatic, biogeochemical, and atmospheric conditions and that will be operated over coming decades to monitor change in the Amazon region, as human perturbations increase in the future. The Amazon Tall Tower Observatory (ATTO) has been set up in a pristine rain forest region in the central Amazon Basin, about 150 km northeast of the city of Manaus. Two 80 m towers have been operated at the site since 2012, and a 325 m tower is nearing completion in mid-2015. An ecological survey including a biodiversity assessment has been conducted in the forest region surrounding the site. Measurements of micrometeorological and atmospheric chemical variables were initiated in 2012, and their range has continued to broaden over the last few years. The meteorological and micrometeorological measurements include temperature and wind profiles, precipitation, water and energy fluxes, turbulence components, soil temperature profiles and soil heat fluxes, radiation fluxes, and visibility. A tree has been instrumented to measure stem profiles of temperature, light intensity, and water content in cryptogamic covers. The trace gas measurements comprise continuous monitoring of carbon dioxide, carbon monoxide, methane, and ozone at five to eight different heights, complemented by a variety of additional species measured during intensive campaigns (e.g., VOC, NO, NO2, and OH reactivity). Aerosol optical, microphysical, and chemical measurements are being made above the canopy as well as in the canopy space. They include aerosol light scattering and absorption, fluorescence, number and volume size distributions, chemical composition, cloud condensation nuclei (CCN) concentrations, and hygroscopicity. In this paper, we discuss the scientific context of the ATTO observatory and present an overview of results from ecological, meteorological, and chemical pilot studies at the ATTO site. </P>

식방풍의 성분분리 및 생리활성

김도훈,한지수,김기은,김진효,김성건,김호경,오오진,황완균,Kim, Do-Hoon,Han, Chi-Su,Kim, Gi-Eun,Kim, Jin-Hyo,Kim, Sung-Gun,Kim, Ho-Kyoung,Oh, O-Jin,Whang, Wan-Kyunn 대한약학회 2009 약학회지 Vol.53 No.3

In this study, isolation of antioxidative compounds was performed for development of anti-oxidizing agent. $CHCl_3$, $H_2O$, 30%, 60% MeOH, MeOH fractions were examined antioxidative activity by DPPH, test of inhibition on NO production. It was revealed that 30%, 60% MeOH and $CHCl_3$ fractions had significant antioxidative activity. In 30% MeOH and 60% MeOH, $CHCl_3$ fraction, six compounds were isolated and elucidated as adenosine(I), guanosine(II), peucedanol 7-O-$\beta$-D-apiofuranosyl(1$\rightarrow$6)-$\beta$-glucopyranoside(III), peucedanol 7-O-$\beta$-D-glucopyranoside(IV), peucedanol(V) and scopoletin(VI) by physicochemical data and spectroscopic methods. (Negative FAB-MS, $^{1}H-NMR$, $^{13}C-NMR$). The results from antioxidative activity screening for the each compound showed that compound IV was relatively superior antioxidant ability. In anti-inflammatory activation assay, compound III, IV, VI had concentration-dependent-activity and compound IV had superior anti-inflammatory ability. These results suggest that Peucedani Radix might be developed as a potent anti-oxidative, anti-inflammatory agents and ingredients for related functional foods.