트랙터 부착용 로더 기구부의 기구학적 시뮬레이션 프로그램 개발

이규승,박원엽,노광모,김준호 성균관대학교 생명공학연구소 1999 生命工學硏究 Vol.5 No.1

A loader mechanism mounted on tractor was modeled for kinematic analysis, and a computer simulation program was developed by using Cartesian coordinate approach, in order to remove the burden of routine derivation and computation from the engineer. The results of kinematic analysis was compared with those of a commercial CAD program. The results of this study was summarized as follows. 1. The results of the simulation showed good agreement with results of the commercial CAD program. This program could be used for predicting the kinematic properties of each links on the loader mechanism. 2. The velocity of bucket which affect the performance of loader increased very quickly just before the finishing point of boom operation, and acceleration also increased sharply at this point. Thus it is concluded that when bucket is rolling, maximum reaction force arises. 3. Velocity and acceleration of each links on the loader mechanism changed very quickly when the bucket cylinder started operation.

有限要素法에 의한 垂直荷重下의 타이어 變形 및 應力解析

하성호,이규승,박원엽 성균관대학교 생명과학자원연구소 1996 生命資源科學硏究 Vol.2 No.2

Tires are made of rubber composites which consist of several plies. Each ply consists of a thin layer of rubber matrix reinforced with unidirectional steel or polyester cords. The deformation and stress analysis of reinforced tires is very difficult because of the material properties and complexity of tire composites. In the present work, the tire inflation and contact problem has been solved by the finite element method in which overcome the complexity of tire composites. The finite element formulation is derived from the equilibrium equations by the principle of virtual work, and the constitutive equation given by the rubber material characteristics. Also, a contact formulation is added to the finite element formulation to calculate the stress distribution of tires in contact with flat rigid road under the vertical load. The calculation for the deformed shape and the stress distribution is executed by dividing into many time steps for incremental analysis. And the solutions of each time step are converged by modified Newton-Raphson iteration method. The results of the finite element analysis of the tire deformation and stress distribution, show good agreement with previous similar analysis of others.

일부 합성피혁 근로자들의 Dimethylformamide, Methyl Ethyl Ketone, Toluene 노출에 따른 요중 대사물질

최호춘,김강윤,안선희,이영자,정규철 한국산업위생학회 2001 한국산업보건학회지 Vol.11 No.2

This study was performed to measure airborne dimethyl-formamide(DMF), methyl ethyl ketone(MEK) and toluene and their urinary metabolites concentrations and to determine the relationship between airborne and urinary concentration. Air-borne samples and their urinary metabolites were measured 98male workers who work for 8 synthetic leather factories in a portion of Kyoung-in area. Urine samples were collected at end-of-shift to estimate the exposure levels. 1. The concentration of airborne DMF by process was 8.81 ppm for wet-mixing, 15.05 ppm for wet-coating, 6.03 ppm for dry-mixing, 5.58 ppm for dry-coating, 5.37 ppm for printing, and 9.03 ppm for total. There was statistically significant difference by process. Urinary NMF concentrations of wet-mixing, Wet-coasting, Dry-mixing, dry-coating and printing were 90.55㎎/, 79.80㎎/ℓ, 39.86㎎/ℓ, 25.23㎎/ℓ, and 38.15㎎/ℓ, respec-tively, and total geometric mean was 56.24㎎/ℓ. There was statistically significant difference by process. 2. The concentration of airborne MEK by process was 1.89 ppm for wet-mixing, 1.96 ppm for wet-coating, 10.33 ppm for dry-mixing, 29.24 ppm for dry-coating, 14.98 ppm for printing, and 4.87 ppm for total. There was statistically significant difference by process. Urinary MEK concentrations of wet-mxing, wet-coating, dry-mixing, dry-coating and printing were 0.93㎎/ℓ, 0.70㎎/ℓ, 3.29㎎/ℓ, 3.29㎎/ℓ, and 1.06㎎/ℓ, res-pectively, and total geometric mean was 1.25㎎/ℓ, There was statistically significant difference by process. Urinary MEK 3.The concentration of airborne toluene by process was 0.35ppm for wet-mixing, 0.42ppm for wet-coating, 2.95ppm for dry-mixing, 11.67ppm for dry-coating, 4.88ppm for printing, 1.24ppm for total. There was statistically significant difference by process. Urinary hippuric acid concentrations of wet-mixing, wet-coating, dry-mixing, dry-coating and printing were 0.24g/g creatinine, 0.21g/g creatinine, 0.34g/g creatinine, 0.52g/g cre-atinine, and 0.29g/g creatinine, respctively and total geometric mean was 0.28g/g creatinine. There was statistically signifi-cant difference by process. 4. No. of exceeded KPEL was 40 workers(40.8%) for DMF(10ppm), 1 worker(1.0%) for MEK(200ppm), and no worker for toluene(100ppm). No. of exceeded KBEI was 62 workers(63.3%) for urinary NMF(40㎎/ℓ), 29 workers (29.6%) for uri-nary MEK, 1 worker(1.0%) for urinary hippuric acid. 5. The regression equations were Log(MMF)=0.4094* Log(DMF)+1.3587(r=0.4516) for DMF, Log(MEKU)=0.1859* Log(MEK)-0.0324(r=0.3303) for MEK, Log(HA)=0.2106* Log(Toluene)-0.5685 (r=4497) for toluene. Synthetic leather factory workers expose to 3 kinds of organic solvents which are DMF, MEK and toluene. Their Uri-nary NMF and MEK levels were higher than their concentration levels through respiratory. It seems that the urinary levels were affected skin absorption for working habit and alcohol intake.

개에 발생한 만성 승모판폐쇄부전증에 대한 Pimobendan 치료 1례

장재임,전형규,최호정,이영원,송근호 忠南大學校 獸醫科大學 附設 動物醫科學硏究所 2006 動物醫科學硏究誌 Vol.14 No.-

A 11-year-old intact male maltese dog with respiratory distress, cyanosis and coughing was referred to the Veterinary Medical Teaching Hospital of Chungnam National University. Loud holosystolic murmur with a palpable precordial thrill was heard at the left apex region by auscultation. Left sided cardiac enlargement and mitral regurgitated flow were detected by thoracic radiography and echocardiography, respectively. Clinical signs were improved by treatment of diuretics, ACE inhibitor and pimobendan.

有限要素法을 利用한 摩察接觸問題의 解析

홍헌석,우호길,이규석 忠南大學校 産業技術硏究所 1996 산업기술연구논문집 Vol.11 No.2

The work presents an analysis of the contact problem between the two frictional elastic bodies. Under the assumption of the unbonded and no penentrating, the contact problem was described as the total potential energy equation. The solution was obtained by the numerical approximation technique finite element method, and iterative method. Several examples were solved to test the presented method. First example is the contact problem between a elastic punch and plate. Second is the contact problem between a elastic connecting rod and shaft. The results were compared with other numerical and analytic solution, and the results were concided with them.

A Mechanism of Recognizing the Presence of a Person Using LWIR-based Thermal Images

Kyou Ho Lee,Young Hun Lee 한국정보기술학회 2017 Proceedings of The International Workshop on Futur Vol.2017 No.7

Peripapillary Choroidal Thickness Change of Polypoidal Choroidal Vasculopathy after Anti-vascular Endothelial Growth Factor

Kyou Ho Lee,Seo Hee Kim,Ji Min Lee,Eui Chun Kang,Hyoung Jun Koh 대한안과학회 2017 Korean Journal of Ophthalmology Vol.31 No.5

Purpose: To investigate the peripapillary choroidal thickness (PCT) of polypoidal choroidal vasculopathy (PCV) and exudative age-related macular degeneration (AMD) and to evaluate their responses to anti-vascular endothelial growth factor (VEGF). Methods: Thirty eyes with PCV and 25 eyes with exudative AMD who were treatment naïve were included in this study. PCT and subfoveal choroidal thickness were evaluated both before and after intravitreal anti-VEGF. Results: The initial mean PCT of PCV (153.78 ± 56.23 μm) was thicker than that of exudative AMD (88.77 ± 23.11 μm, p < 0.001). Temporal, superior, nasal, and inferior PCTs of PCV were all thicker than those observed in exudative AMD (all p < 0.05). After anti-VEGF, the mean PCT of PCV was significantly reduced (134.17 ± 41.66 μm, p < 0.001), but the same was not true not in exudative AMD (86.87 ± 22.54 μm, p = 0.392). PCT showed a similar tendency in all quadrants. Conclusions: PCV exhibits a thick choroid in the peripapillary region. PCT decreases after anti-VEGF in PCV but not in exudative AMD. In exudative AMD, subfoveal choroidal thickness decreased, but that in the peripapillary region did not.

P102 : Effect of escitalopram on erythematotelangiectatic rosacea

( Kyou Chae Lee ),( Sang Lim Kim ),( Jin Sub Lee ),( Yoon Hyuk Choi ),( Hyun Ho Son ),( Hong Dae Jung ),( Yong Hyun Jang ),( Seok Jong Lee ),( Do Won Kim ),( Weon Ju Lee ) 대한피부과학회 2013 대한피부과학회 학술발표대회집 Vol.65 No.2

Background: There is no satisfactory treatment for erythematotelangiectatic rosacea. Objectives: To investigate the effect of escitalopram for the treatment of erythematotelangiectatic rosacea Methods: Twenty four subjects (male to female: 3:20, mean age: 44.4 years) were enrolled. Exacerbating factors were analyzed with questionnaire. Escitalopram was given at a dose of 5 mg/day for 8 weeks. Evaluation was performed at baseline and at week 8 and 24. Efficacy was evaluated through severity, investigator`s global assessment (IGA), subjective satisfaction score (SSS), chromameter and skin function test. Safety was monitored through adverse effects. Results: Exacerbating factors were sunlight, stress and hot bathing. At week 8, subjects achieved a significant decrease from 44 to 30 in severity (p<0.05). Out of 23 subjects, 5 were ranked fair, 12 good and 6 excellent in IGA. In addition, 4 were ranked fair, 12 good and 7 excellent in SSS. Chromameter showed statistically significant improvement after treatment with escitalopram, from 19.26 to 17.43 (P<0.05). Skin hydration by corneometer showed a statistically significant increase from 64.91 to 73.62 (p<0.05). Mild adverse effects, such as insomnia, facial swelling and drowsiness, were reported. At week 24, subjects achieved much more improvement in severity, IGA, SSS and chromameter. Conclusion: Escitalopram may be a useful and safe treatment option for the management of erythematotelagiectatic rosacea.

A role for Leu247 residue within transmembrane domain 2 in ginsenoside-mediated α7 nicotinic acetylcholine receptor regulation

Lee, Byung-Hwan,Choi, Sun-Hye,Pyo, Mi Kyung,Shin, Tae-Joon,Hwang, Sung-Hee,Kim, Bo-Ra,Lee, Sang-MoK,Lee, Jun-Ho,Lee, Joon-Hee,Lee, Hui Sun,Choe, Han,Han, Kyou-Hoon,Kim, Hyoung-Chun,Rhim, Hyewhon,Yong, Springer-Verlag 2009 Molecules and cells Vol.27 No.5

<P>Nicotinic acetylcholine receptors (nAChRs) play important roles in nervous system functions and are involved in a variety of diseases. We previously demonstrated that ginsenosides, the active ingredients of Panax ginseng, inhibit subsets of nAChR channel currents, but not alpha7, expressed in Xenopus laevis oocytes. Mutation of the highly conserved Leu247 to Thr247 in the transmembrane domain 2 (TM2) channel pore region of alpha7 nAChR induces alterations in channel gating properties and converts alpha7 nAChR antagonists into agonists. In the present study, we assessed how point mutations in the Leu247 residue leading to various amino acids affect 20(S)-ginsenoside Rg(3) (Rg(3)) activity against the alpha7 nAChR. Mutation of L247 to L247A, L247D, L247E, L247I, L247S, and L247T, but not L247K, rendered mutant receptors sensitive to Rg(3). We further characterized Rg(3) regulation of L247T receptors. We found that Rg(3) inhibition of mutant alpha7 nAChR channel currents was reversible and concentration-dependent. Rg(3) inhibition was strongly voltage-dependent and noncompetitive manner. These results indicate that the interaction between Rg(3) and mutant receptors might differ from its interaction with the wild-type receptor. To identify differences in Rg(3) interactions between wild-type and L247T receptors, we utilized docked modeling. This modeling revealed that Rg(3) forms hydrogen bonds with amino acids, such as Ser240 of subunit I and Thr244 of subunit II and V at the channel pore, whereas Rg(3) localizes at the interface of the two wild-type receptor subunits. These results indicate that mutation of Leu247 to Thr247 induces conformational changes in the wild-type receptor and provides a binding pocket for Rg(3) at the channel pore.</P>

An ICT-based Solution to Identification and Investigation for Transportational Entrance to Ports

Kyou Ho Lee,Young Hun Lee 한국정보기술학회 2017 Proceedings of The International Workshop on Futur Vol.2017 No.5