• Journal of Mechanical Science and Technology
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• 제19권4호
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• pp.936-946
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• 2005

The liquid nitrogen as an environmentally safe coolant has been widely recognized in cryo­genic machining, its function as a lubricant is plausible due to its chemical inertness, physical volatility and low viscosity. Since a reduced friction is a direct witness of the lubrication effect from a tribological viewpoint, this paper presents an evaluation of the apparent friction coefficient on the tool-chip interface in cryogenic cutting operations to prove and characterize the lubricity of LN2 in cryogenic machining. The cryogenic cutting technology used in this study is based on a cooling approach and liquid nitrogen delivery system which are intended to apply liquid nitrogen in well-controlled fine jets to selectively localized cutting zones and to penetrate liquid nitrogen to the tool-chip interface. It has been found that the apparent friction coefficient can be significantly reduced in cryogenic machining, depending on the approach of liquid nitrogen delivery.

• 한국산학기술학회논문지
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• 제19권12호
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• pp.178-185
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• 2018

노인 운전자가 스스로 운전능력을 점검하는 자가-보고식 평가는 운전 중 사고 또는 사고위험성을 사전에 대비할 목적으로 사용된다. 지역사회에 거주하는 정상노인의 다수가 경도인지장애로 인해 인지기능 저하를 경험할 수 있으며, 이들의 저하된 인지기능은 노인 운전자용 자가-보고식 평가 수행에 영향을 미치는 변수가 될 수 있다. 따라서 본 연구를 통해 지역사회에 거주하는 경도인지장애 노인 운전자가 자가-보고식 평가를 수행하는 데 있어 영향을 미치는 인지기능을 확인하였다. 지역사회에 거주하는 노인 운전자 103명의 Korean Version of the Montreal Cognitive Assessment 평가결과를 바탕으로 경도인지장애와 정상 노인을 분류하였다. 그리고 두 집단의 자가-보고식 평가인 Korean-Drivers 65 plus 점수를 비교하였고, 이 평가 결과에 영향을 미치는 인지기능을 분석하였다. 그 결과 경도인지장애 그룹이 정상 그룹과 비교하여 유의하게 낮은 평가수행 결과를 보였으며, 경도인지장애 노인 운전자의 자가-보고식 평가 결과는 시공간 실행력 및 지연 회상력과 유의한 상관성이 확인되었다. 회귀분석을 통해 자가-보고식 평가 수행에 영향을 미치는 인지기능을 확인한 결과 시공간 실행력이 가장 영향력인 높은 변수로 확인되었다. 지연 회상력 또한 부분적 영향이 확인되었지만 경도인지장애 노인 운전자의 자가-보고식 평가 결과를 변질 시키는 수준은 아닌 것으로 확인되었다.

• 대한후두음성언어의학회지
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• 제9권1호
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• pp.71-78
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• 1998

Type Ⅰ thyuroplasty in conjunction with arytenoid adduction is one of the excellent techniques in the treatment of unilateral vocal fold paralysis. But perioperative objective evaluation of the patients is difficult. With the development of the videostroboscopy and image analysis program, we could quantify the Glottal Area Waveform(GAW) in patients with unilateral vocal fold paralysis and investigated the relationship between the glottal area and aerodynamic and acoustic parameters. Eight female patients who were performed type Ⅰ thyroplasty in conjunction with arytenoid adduction and 5 females with normal vocal function were involved in this study. Preoperative and postoperative videostroboscopy and vocal function study wire performed. GAW was analysed quantitatively with image analysis program (Kay Stroboscope Image analysis, KSIP) Peak Glottal Area(PGA), Baseline Offset(BO), and Closing Phase(CP) were increased in patients with unilateral vocal fold paralysis and they were reduced after the operation. Mean flow Rate (MFR) was well correlated with the PGA in normal control group and unilateral vocal fold paralysis patients. Noise to harmonic ratio(NHR) was correlated with PGA only in preoperative unilateral vocal fold paralysis patients. In conclusion quantitative measurement of the GAW is useful method in evaluation of unilateral vocal f31d paralysis patients.

• 한국의류산업학회지
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• 제17권5호
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• pp.800-814
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• 2015

This study develops baseball uniforms for amateur baseball players with excellent appearance and functional movement. This study selected a conventional baseball uniform and developed a new one for amateur baseball players with improved function and appearance based on previous research results. In case of developed baseball uniform materials, this study used polyurethane mixed fabric for the top to improve flexibility. A mesh material was used at the armpit, back, and bottom of the top, side line of pants and pockets to improve breathability. In addition, quilted material was added to the knee to improve durability and protection. For the patterns and design, this study used a gusset under the arm to assist in comfortable movement as well as reduced the length of the top and circumference of the hem to decrease unnecessary parts. For the pants, this study used a waistband gripper to avoid the top riding up, added darts behind the knees to bend comfortably, and added additional fabric inside the hem to prevent dirt. In addition, we reduced the width and length of the pants. Wearing evaluation was divided into appearance evaluation by experts and on-site-wearing test by baseball players. The wearing evaluation results for the developed baseball uniform indicated higher evaluations than a conventional baseball uniform in all sections as well as showed significant differences in all sections. The result of movement adaptability evaluation showed the highest satisfaction for 'the top does not ride up' and 'dirt do not get in'.

• The Journal of Korean Physical Therapy
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• 제22권3호
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• pp.37-44
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• 2010

Purpose: The purpose of this study was to describe the functional (mobility, self-care, social ability) and health-related quality of life in children with cerebral palsy (CP). Methods: A cross- sectional survey of 202 children with CP, mean age $5.91{\pm}1.57$ years, was carried out using the Gross Motor Function Classification System (GMFCS), Gross Motor Function Measure (GMFM), Pediatric Evaluation of Disability Inventory (PEDI), and Child Health Questionnaire (CHQ). Results: The functional assessment of children with CP showed that a more severe GMFCS level was associated with lower functional abilities (p<0.05). The health-related quality of life assessment showed that psychosocial well-being was less impaired than physical well-being. The internal consistency of the three instruments was satisfactory (cronbach's ${\alpha}$>0.80). The three different scales were correlated from moderate to strong (r=0.44 to 0.92). It was also found that mobility, tone distribution, and the parents' education level exerted a significant effect on the quality of life of children with CP (p<0.05). Conclusion: These findings suggest that children with CP have reduced function and quality of life and these are influenced by various factors. However, planning and application of various task-oriented functional interventions to childhood CP may be useful.

• 상하수도학회지
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• 제23권1호
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• pp.107-112
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• 2009

This study was conducted for verification and systematization of estimation method about the headloss using CFD(Computational Fluid Dynamics). Head loss which happens between the inlet and outlet of in-line mixer can be a major factor for the design and construction. Also, this Case studies about the sensitivity related to the velocity in the piping system. As result, program's default calculation function was used to get each side's total pressure and the differential of each total pressure could be defined as head loss from in-line mixer. In the case of adopting pipe surface friction factor and geometry loss, Calculation residual can be much more reduced. It was found that residual of value between CFD method and field test ranged about 3 through 18 precent.

• 한국환경보건학회지
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• 제28권3호
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• pp.26-33
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• 2002

Adolescents exposed chronically to tobaccotobacco smoke have been found to have reduced pulmonary function as well as an increased risk of lung cancer and a serious heart disease. Consequently, reducing exposure to tobacco smoke is an important public health goal. This study was conducted to develope the exact evaluation method of student smoker or heavy exposure from ETS, and the change on smoking behavior and attitude after a stop-smoking program. From the study, we concluded that the cotinine concentrations in saliva from students indicate exactly whether they are smoker or not. Also, it was found that the more and exact informations from both the cotinine analysis and the questionnaire were obtained than from only the questionnaires. The non-smokers had more positive effects on the changes of cog-nitions, behaviors and attitude about passive-smoking after a stop-smoking program than the smokers. The results of this study show that through both the accurate determination of cotinine in saliva and the questionnaires, the smoking status and the tobacco education effectiveness can be predicted.

• The Korean Journal of Physiology
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• 제23권2호
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• pp.225-236
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• 1989

1) At the isolated perfused guinea-pig and rat heart heterometric autoregulation of the myocardium and myogenic autoregulation of the coronary vessels were induced by means of stepwise increases of perfusion pressure. 2) According to this loading test Frank-Starling function curves of the left ventricle and pressure-flow curves of the coronary vessels can be drawn. This graphic evaluation gives more information about the condition of the heart and the coronary vessels than simple evaluation under hemodynamic equilibrium. 3) There are significant differences in both curves between animal species and between different perfusate Mg concentration. 4) Myogenic autoregulation is not affected by the cyclooxygenase inhibitors indometacin and me- clofenamate. Thus it appears unlikely that prostanoides are involved in myogenic autoregulation. 5) Ca antagonists (Gallopamil, prenylamine) depress myogenic autoregulation dose-dependently. Enhanced myogenic autoregulation, induced by low extracellular magnesium, can be reduced effectively by Gallopamil. 6) Ginsenosides from Panax ginseng as well as the ginsenoside 'Rg' are effective inhibitors of myogenic autoregulation without major negative inotropic effects.

• Journal of Ginseng Research
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• 제40권4호
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• pp.334-343
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• 2016

Background: Progressed tissue culture techniques have allowed us to easily obtain mass products of tissue-cultured mountain ginseng over 100 yr old (TCMG-100). We investigated the effects of TCMG-100 extract on erectile function using in vitro and in vivo studies. Methods: To examine the relaxation effects and mechanisms of action of TCMG-100 on rabbit cavernosal strips evaluated in an organ bath. To investigate the long-term treatment effect of TCMG-100, 8-wk administration was performed. After administration of TCMG-100, intracavernosal pressure, cyclic guanosine monophosphate and nitric oxide (NO) levels of cavernosal tissue, serum testosterone level, histological observation of collagen fiber, endothelium, smooth muscle cell, and transforming growth factor-${\beta}1$ were investigated. Results: TCMG-100 extract displayed dose-dependent relaxation effects on precontracted rabbit corporal smooth muscle. The TCMG-100-induced relaxation was significantly reduced by removing the endothelium, and treatment with an NO synthase inhibitor or NO scavenger. Eight weeks of TCMG-100 administration increased intracavernosal pressure in a rat model. The levels of cyclic guanosine monophosphate and NO in the corpus callosum and serum testosterone level were also increased by TCMG-100 treatment. Furthermore, histological evaluation of collagen, smooth muscle, and endothelium showed increases in endothelium and smooth muscle, and a decrease in transforming growth factor-${\beta}1$ expression. Conclusion: These relaxation effects on corporal smooth muscle and increased erectile function suggest that TCMG-100 might be used as an alternative herbal medicine to improve erectile function.

• International journal of advanced smart convergence
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• 제8권4호
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• pp.26-33
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• 2019

We conducted research to evaluate economically and engineering about the synthesis of Magnesium Oxide, MgO, nanoparticles using physicochemical methods. The method used was economic evaluation by calculating GPM, BEP, PBP, and CNPV. The other method used was engineering perspective. MgO nanoparticles were synthesized by reacting Mg(NO₃)₂ and NaOH with a mole ratio 1: 2. Mg(OH)₂ formed was heated and calcined to remove water content and to oxidation to form MgO. An economic evaluation by calculating GPM and CNPV for the production of MgO nanoparticles on an industrial scale shows that the payback period (PBP) occur in the third year and profits increase each year. Tax variations show that the higher of tax, the lower profits received. When there was an increase of selling prices, the profit was greater. The variable cost used is the price of raw material. When there was an increased in the variable cost price, the payback period was longer and the profits was reduced. The benefit of this research is knowing the industrial production of MgO nanoparticles is beneficial. The function of MgO nanoparticles is a material for the manufacture of ceramics and can be used as an antimicrobial in the water filtration process.