• Journal of Microbiology
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• 제35권3호
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• pp.234-238
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• 1997

Conditional lethal mutation nup49-1 of a nuclear pore complex component gene was constructed in Saccharomyces cerevisiae. This mutation deleted one third of the essential NUP49 gene at the carboxy-terminal, but retained 13 repeats of the highly conserved GLFG domain. The nup49-1 mutant strain was viable with a slow-growth phenotype, indicating that the C-terminal is dispensable at normal growth temperature. This strain exhibited both temperature-sensitivity at 37.deg.C and cold-sensitivity at 16.deg.C. Temperature shift experiments revealed that the arrest phenotype at 37.deg.C was random in the cell division cycle. The nup49-1 mutation was tested to be recessive and is expected to be useful for the functional analysis of nuclear pore complex proteins as well as for studies of nuclear transport systems.

• Korean Chemical Engineering Research
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• 제61권4호
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• pp.542-549
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• 2023

대안 모델링에 대한 관심이 커진 이후 데이터 기반의 기계학습을 이용하여 비선형 화학 공정을 모사하고자 하는 연구가 지속되고 있다. 그러나 기계 학습 모델의 black box 성질로 인하여 모델의 해석 가능성에 한계는 산업 적용에 걸림돌이 되고 있다. 따라서, 모델의 정확도가 보장된 상태에서 해석력을 부여하는 개념인 설명 가능한 인공지능(explainable artificial intelligence, XAI)을 이용하여 화학 공정 분석을 시도하고자 한다. 기존의 화학 공정 민감도 분석이 변수의 민감도 지수를 계산하고 순위를 매기는 데에 그쳤다면, XAI를 이용하여 전역적, 국소적 민감도 분석뿐만 아니라 변수들 간의 상호작용에 대하여 분석하여 데이터로부터 물리적 통찰을 얻어내는 방법론을 제안한다. 사례 연구의 대상공정인 암모니아 합성 공정에 대하여 첫번째 반응기로 향하는 흐름에 대한 예열기(preheater)의 온도, 세 반응기로 향하는 cold-shot의 분배 비율을 공정 변수로 설정하였다. Matlab과 Aspen plus를 연동하여 공정 변수를 바꿔가면서 암모니아의 생산량과 세 반응기의 최고 온도에 대한 데이터를 얻었으며, tree 기반의 모델들을 훈련시켰다. 그리고 성능이 좋은 모델에 대하여 XAI 기법 중 하나인 SHAP 기법을 이용하여 민감도 분석을 수행하였다. 전역적 민감도 분석 결과, 예열기의 온도가 가장 큰 영향을 미쳤으며 국소적 민감도 분석 결과에서 생산성 향상 및 과열 방지를 위한 공정 변수들의 범위를 규정할 수 있었다. 이처럼 화학 공정의 대안 모델을 구축하고 설명 가능한 인공지능을 이용해 민감도 분석을 진행하는 방법론을 통해 공정 최적화에 대한 정량적, 정성적 피드백을 제안하는 데 도움을 줄 것이다.

• 소성∙가공
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• 제27권6호
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• pp.370-378
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• 2018

Cold forging, carried out at room temperature, leads to high dimensional accuracy and excellent surface integrity as compared to other forging methods such as warm and hot forgings. In the cold forging process, WC-Co (Tungsten Carbide-Cobalt) alloy is the mainly used material as a core dies because of its superior hardness and strength as compared to other structural materials. For cold forging, die life is the most significant factor because it is directly related to the manufacturing cost due to periodic die replacement in mass production. To investigate die life of WC-Co alloy for cold forging, mechanical properties such as strength and fatigue are essentially necessary. Generally, uniaxial tensile test and fatigue test are the most efficient and simplest testing method. However, uniaxial tension is not efficiently application to WC-Co alloy because of its sensitivity to alignment of the specimen due to its brittleness and difficulty in thread machining. In this study, shape of specimen, tools, and testing methods, which are appropriate for uniaxial tensile test for WC-Co alloy, are proposed. The test results such as Young's modulus, tensile strength and stress-strain curves are compared to those in previous literature to validate the proposed testing methods. Based on the validation of test results it was concluded that the newly developed testing method is applicable to other cemented carbides like Titanium carbides with high strength and brittleness, and also can be utilized to carry out fatigue tests for further investigation on die life of cold forging.

• 대한한방체열의학회지
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• 제1권1호
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• pp.7-12
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• 2002

Cold hypersensitivity is excessive sensitivity of each body part, particularly limbs and low backs, but sometimes it affects upper abdomen region in G-I trouble patients. We conducted this research on 69 patients who came and took the both exam of gastroscopy and D.I.T.I. in Kangnam korean hospital Kyung Hee university. So, we researched the significance of temperature deviations on upper abdomen which was studied separately by gastritis group, digestive function group and H. pylori group. The result was : 1. The temperature deviation of Zhongwan(Ren12)-Danzhong(Ren17) of gastritis group was significant, it means that patients with severe gastritis have more significant cold hypersensitivity in upper abdomen than the patients who has not gastritis(p<0.005). 2. The temperature deviation of Zhongwan(Ren12)-Danzhong(Ren17) of indigestive patients in digestive function group was significant(p<0.05) 3. The temperature deviation of Zhongwan(Ren12)-Danzhong(Ren17) of H.pylori positive patients in H.pylori group was not significant. 4. The clinical relationship or tendency was not found both between H.pylori group and gastritis group and between H.pylori group and digestive function group.

• 대한기계학회논문집A
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• 제27권8호
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• pp.1398-1408
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• 2003

Tensile and LCF(low cycle fatigue) tests were carried out in air at wide temperature range 20$^{\circ}C$-750$^{\circ}C$ and strain rates of 1${\times}$10$\^$-4//s-1${\times}$10$\^$-2/ to ascertain the influence of strain rate on tensile and LCF properties of prior cold worked 316L stainless steel, especially focused on the DSA(dynamic strain aging) regime. Dynamic strain aging induced the change of tensile properties such as strength and ductility in the temperature region 250$^{\circ}C$-600$^{\circ}C$ and this temperature region well coincided with the negative strain rate sensitivity regime. Cyclic stress response at all test conditions was characterized by the initial hardening during a few cycles, followed by gradual softening until final failure. Temperature and strain rate dependence on cyclic softening behavior appears to result from the change of the cyclic plastic deformation mechanism and DSA effect. The DSA regimes between tensile and LCF loading conditions in terms of the negative strain rate sensitivity were well consistent with each other. The drastic reduction in fatigue resistance at elevated temperature was observed, and it was attributed to the effects of oxidation, creep and dynamic strain aging or interactions among them. Especially, in the DSA regime, dynamic strain aging accelerated the reduction of fatigue resistance by enhancing crack initiation and propagation.

• Journal of Periodontal and Implant Science
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• 제35권4호
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• pp.991-1002
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• 2005

The purpose of this study was to compare the effect of desensitizing agents applied on hypersensitive root surface following periodontal treatment. This study included 21 subjects(168 vital teeth). To evaluate dentin sensitivity, three clinical tests(tactile, air stream, cold water) were tried and three different densensitizing agents(MS coat, Elmex gel. Superseal) were individually applied. After application, reassessment was done at 1 minute, 1 week, 1 month and 3 months. The results were as follows : 1. The degree of dentin sensitivity was measured highly in the sequence of cold water, air stream and tactile and significantly decreased in all four groups with lapse of time(p<0.05). 2. There was no significant difference between all four groups in the tactile test with lapse of time. 3. There was no significant difference between three experimental groups in the air stream test with lapse of time. however, one minute later, it was measured highly in the sequence of Superseal, MS coat and Elmex 4. There was no significant difference between three experimental groups in the cold water test with lapse of time. As a result of this study, all of three agents were significantly effective in reducing dentin hypersensitivity and these agents could be positively employed to patients complaining of dentin hypersensitivity following periodontal treatment.

• Nuclear Engineering and Technology
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• 제8권4호
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• pp.203-207
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• 1976

질칼로이-4에 있어서 flow stress strain rate 의존성을 냉간가공 및 소둔된 시편에 대해 20$0^{\circ}C$-45$0^{\circ}C$ 온도 구간에서 응력이완 실험으로 조사하였다. 전체 실험온도에서 In-3-ln i 관계식은 $10^{-5}$-$10^{-3}$ sec$^{-1}$ strain rate의 구간에 걸쳐 선형관계를 보였다. 냉간 가공된 질칼로이 -4의 strain rate sensitivity, m값은 30$0^{\circ}C$에서 최소값을 보인 반면, 소둔된 시편의 경우 30$0^{\circ}C$와 45$0^{\circ}C$에서 최소값들을 보였다. 최소값의 m이 나타나는 온도는 가공시효값이 극대값을 보이는 온도와 일치한다는 사실이 확인되었다. m값의 감소는 활동자유전위들이 산소원자에 의해 pinning된 결과로 유발되는 가공 시효와 관련된 것으로 고려된다. 그리고 소둔된 시편이 45$0^{\circ}C$에서 가지는 최소 m값은 철 원자들로 인한 가공 시효에서 기인된 것으로 생각된다.

• 대한한의학회지
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• 제42권4호
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• pp.102-119
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• 2021

Objectives: Facial diagnosis is an important part of clinical diagnosis in traditional East Asian Medicine. In this paper, using a fully automated facial shape analysis system, we show that facial morphological features are associated with cold pattern. Methods: The facial morphological features calculated from 68 facial landmarks included the angles, areas, and distances between the landmark points of each part of the face. Cold pattern severity was determined using a questionnaire and the cold pattern scores (CPS) were used for analysis. The association between facial features and CPS was calculated using Pearson's correlation coefficient and partial correlation coefficients. Results: The upper chin width and the lower chin width were negatively associated with CPS. The distance from the center point to the middle jaw and the distance from the center point to the lower jaw were negatively associated with CPS. The angle of the face outline near the ear and the angle of the chin line were positively associated with CPS. The area of the upper part of the face and the area of the face except the sensory organs were negatively associated with CPS. The number of facial morphological features that exhibited a statistically significant correlation with CPS was 37 (unadjusted). Conclusions: In this study of a Korean population, subjects with a high CPS had a more pointed chin, longer face, more angular jaw, higher eyes, and more upward corners of the mouth, and their facial sensory organs were relatively widespread.

• 대한한방내과학회지
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• 제43권6호
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• pp.1063-1074
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• 2022

Objectives: The aim of this study was to investigate the differences in the prevalence of metabolic syndrome (MetS) according to the Sasang constitution (SC) and cold and heat pattern identification (CHPI). Methods: SC, CHPI, MetS, and component data were obtained from 2,561 participants in 26 Korean medical clinics from 2007 to 2013. SC, diagnosed by Korean medicine doctors, was confirmed by positive responses to herbal medicines administered according to that constitution. The CHPI was verified by a questionnaire about thermal sensitivity and drinking habits. The diagnosis criteria for MetS were: 1) waist circumference (WC) ≥90 cm (male) and ≥80 cm (female); 2) triglycerides ≥150 mg/dL; 3) high density lipoprotein cholesterol (HDL) <40 mg/dL (male) and <50 mg/dL (female); 4) blood pressure ≧130/85 mmHg; and 5) fasting blood glucose ≥100 mg/dL. Odds ratios (ORs) and differences in MetS and its components were compared using logistic regression and ANCOVA. Results: The MetS prevalence rates were 54.1%, 22.0%, and 33.3% for Taeeumin (TE), Soeumin (SE), and Soyangin (SY), respectively, and 30.5% and 44.5% for the cold and heat patterns, respectively. ANCOVA for MetS components showed significantly higher WC in TE than in SE or SY, and all components except HDL were higher in the heat pattern group than in the cold pattern group. Logistic regression for MetS prevalence showed a significant association between TE and the heat pattern group (OR=1.653) but not for non-TE and the cold pattern group. Conclusions: Considering SC and CHPI together may be more effective in managing MetS than considering SC alone.

• 한국유체기계학회 논문집
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• 제15권6호
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• pp.39-45
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• 2012

This paper describes the outcome of the design of a 200 kW class micro gas turbine and the sensitivity of its performance (efficiency and power) to the variations in major design parameters. The reference design parameters were set up based on the best available component technologies. The resulting net electricity generation efficiency of the micro gas turbine package was found to be competitive to those of other systems in the market. The sensitivities of power and efficiency to the variations in compressor and turbine efficiencies, pressure ratio, turbine inlet temperature, recuperator effectiveness, secondary air ratio, pressure loss ratios of both the cold and hot sides of the recuperator were estimated. Based on the sensitivity data, a simplified method to predict the variation in system performance responding to the combinations of small changes in all design parameters were set up and validated.