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김문헌,권영필,신치웅 崇田大學校 1981 論文集 Vol.11 No.1
The objective of this paper is to simulate the performance of H₂O-LiBr absorption refrigerator. The thermodynamic cycle of the H₂O-LiBr simple effect absorption refrigeration is analyzed and the coefficient of performance is derived for an ideal cycle. Equation for thermodynamic properties of LiBr solution and water are obtained by the least square method from equilibrium charts. And a computer program is developed, which can calculate the circulation ratic and the coefficient of performance from the efficiency of the heat exchanger and temperatures of generator, condenser, evaporator and absorber. The simulation of the performance by the computer shows the following characteristics. When the efficiency of the heat exhcnanger increase, the COP volue increases and the operating range is reduced by recry stallization. When the generator temperature increase, the COP value increases at a high condensor temperature but decrease at a low condenser temperature. However the COP value always increases as the condenser temperature decreases. It is more effective for high COP value to decrease the condenser temperature than to increase the generator temperature.
Mun Chi-Woong,Choi Ki-Sueng,Shin Oon-Jae,Yang Young-Ill,Chang Hee-Kyung,Hu Xiaoping,Eun Chung-Ki The Korean Society of Medical and Biological Engin 2006 의공학회지 Vol.27 No.2
In this study, transverse relaxation time (T2) measurement and the evaluation of the characteristics of the spectral peak related to stomach tissue metabolites were performed using ex vivo proton magnetic resonance spectroscopic imaging (MRSI) at 1.5-T MRI/S instruments. Thirty-two gastric tissues resected from 12 patients during gastric cancer surgery, of which 19 were normal tissue and 13 were cancerous tissue, were used to measure the $T_2$ of the magnetic resonance spectroscopy (MRS) peaks. The volume of interest data results from the MRSI measurements were extracted from the proper muscle (MUS) layer and the composite mucosa/submucosa (MC/SMC) layer and were statistically analyzed. MR spectra were acquired using the chemical shift imaging (CSI) point resolved spectroscopy (CSI-PRESS) technique with the parameters of pulse repetition time (TR) and echo times (TE) TR/(TE1,TE2)=1500 msec/(35 msec, 144 msec), matrix $size=24{\times}24$, NA=1, and voxel $size=2.2{\times}2.2{\times}4mm^3$. In conclusion, the measured $T_2$ of the metabolite peaks, such as choline (3.21ppm) and lipid (1.33ppm), were significantly decreased (p<0.01 and p<0.05, respectively) in the cancerous stomach tissue.
핵자기공명분광법에 사용되는 D2O 및 TSP의 세포 독성 평가
문치웅 ( Chi Woong Mun ),곽소영 ( So Young Kwak ),장무영 ( Moo Young Jang ) 한국조직공학·재생의학회 2012 조직공학과 재생의학 Vol.9 No.2s
Nuclear magnetic resonance (NMR) spectroscopy has been being used to identify cell metabolite and differentiation with reference material (TSP) and locking solvent (D2O). The aim of this study is to evaluate the cytotoxicity of TSP and D2O which have been widely used for NMR research. MG-63 and hMSC were selected and cultured in 3-dimensions on alginate bead for cytotoxicity test. The statistical analysis was performed after identifying the cell viability in accordance with various concentrations and exposure time of TSP and D2O. There was significant difference of cell viability between two concentrations (40% and 100%) of locking solvent (D2O). Our results indicate that the increased concentration of D2O effects the reduction of cell viability on two different cell types (MG-63: 4%, hMSC:14~40%). However, there was no significant difference by concentration of TSP. The statistical significance and cytotoxicity of concentration were found on D2O but not on TSP except for exposed hMSC for 24 hours from TSP. No statistical significance was found according to exposure time of D2O and TSP. We concluded that TSP still can be used for NMR but the use of D2O should be prohibited when identifying cell metabolite and differentiation. So, another locking solvent except D2O is needed.
인체의 위 조직 시료에서 자기공명영상장치를 이용한 확산계수 측정에 대한 기초 연구
문치웅,최기승,양영일,장희경,은충기,Mun Chi-Woong,Choi, Ki-Sueng,Nana Roger,Hu, Xiaoping P.,Yang, Young-Il,Chang Hee-Kyung,Eun, Choong-Ki 대한의용생체공학회 2006 의공학회지 Vol.27 No.5
The aim of this study is to investigate the feasibility of ex vivo MR diffusion tensor imaging technique in order to observe the diffusion-contrast characteristics of human gastric tissues. On normal and pathologic gastric tissues, which have been fixed in a polycarbonate plastic tube filled with 10% formalin solution, laboratory made 3D diffusion tensor Turbo FLASH pulse sequence was used to obtain high resolution MR images with voxel size of $0.5{\times}0.5{\times}0.5mm^3\;using\;64{\times}32{\times}32mm^3$ field of view in conjunction with an acquisition matrix of $128{\times}64{\times}64$. Diffusion weighted- gradient pulses were employed with b values of 0 and $600s/mm^2$ in 6 orientations. The sequence was implemented on a clinical 3.0-T MRI scanner(Siemens, Erlangen, Germany) with a home-made quadrature-typed birdcage Tx/Rx rf coil for small specimen. Diffusion tensor values in each pixel were calculated using linear algebra and singular value decomposition(SVD) algorithm. Apparent diffusion coefficient(ADC) and fractional anisotropy(FA) map were also obtained from diffusion tensor data to compare pixel intensities between normal and abnormal gastric tissues. The processing software was developed by authors using Visual C++(Microsoft, WA, U.S.A.) and mathematical/statistical library of GNUwin32(Free Software Foundation). This study shows that 3D diffusion tensor Turbo FLASH sequence is useful to resolve fine micro-structures of gastric tissue and both ADC and FA values in normal gastric tissue are higher than those in abnormal tissue. Authors expect that this study also represents another possibility of gastric carcinoma detection by visualizing diffusion characteristics of proton spins in the gastric tissues.
Reduction of ipsilateral thalamic volume in temporal lobe epilepsy with hippocampal sclerosis
Park, Kang Min,Kim, Tae Hyung,Mun, Chi Woong,Shin, Kyong Jin,Ha, Sam Yeol,Park, JinSe,Lee, Byung In,Lee, Ho-Joon,Kim, Sung Eun CHURCHILL LIVINGSTONE 2018 JOURNAL OF CLINICAL NEUROSCIENCE Vol.55 No.-
<P><B>Abstract</B></P> <P>The thalamus plays an important role in the modulation of both focal and generalized seizures, but the mechanisms related to seizures may be different among epilepsy syndromes. The aim of this study is to investigate the thalamic atrophy in different epilepsy syndromes. We enrolled a total of 72 patients with epilepsy (22 patients with temporal lobe epilepsy with hippocampal sclerosis, 21 patients with extra-temporal lobe epilepsy, and 29 patients with juvenile myoclonic epilepsy). We analyzed structural volumes of the brain with FreeSurfer 5.1 software, and compared them among subgroups of epilepsy and normal control subjects. Moreover, we quantified correlations between the duration of epilepsy and the structural volumes with age and sex as covariates. The volumes of the ipsilateral hippocampus in temporal lobe epilepsy with hippocampal sclerosis were significantly smaller than those in extra-temporal lobe epilepsy and normal control subjects [analysis of variance (ANOVA), p < 0.001]. Although the volumes of the ipsilateral thalamus were not different from those of normal control subjects, the volumes of the ipsilateral thalamus were negatively correlated with duration of epilepsy in temporal lobe epilepsy with hippocampal sclerosis (r = −0.5, <I>p</I> = 0.02). However, the volumes of interest in extra-temporal lobe epilepsy and juvenile myoclonic epilepsy were not different from those in normal control subjects, and none of these structures were correlated with duration of epilepsy. These findings suggest that the role of the thalamus may be different in thalamo-limbic circuits among epilepsy syndromes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We investigate the thalamic atrophy in different epilepsy syndromes. </LI> <LI> There is a reduction of ipsilateral thalamic volume only in temporal lobe epilepsy with hippocampal sclerosis. </LI> <LI> The role of the thalamus is different in thalamo-limbic circuits among epilepsy syndromes. </LI> </UL> </P>