• 한국광학회지
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• 제9권2호
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• pp.111-116
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• 1998

활성층의 변형이 0.9%의 압축변형에서 1.4%의 인장변형에 이르는 13개의 InGaAs/InGaAsP 따로가둠 이종접합 다중양자우물 레이저의 문턱전류밀도 값을 계산하여, 변형이 문턱전류밀도에 미치는 영향을 살펴보았다. 양자우물의 띠간격이 1.55.mu.m가 되도록 양자우물의 두께를 정하였고, 레이저의 이득계산을 위한 띠구조 및 전이행렬요소의 계산에는 블록대각화된 8 * 8 이차 $k^{\rarw}$ * $p^{\rarw}$ 해밀토니안을 사용하여 전도띠의 비포물선형 효과 및 원자가띠의 섞임을 모두 고려하였다. 실온의 문턴전류밀도는 중양공띠와 경양공띠가 교차하는 0.4% 인장변형의 값과 두번째 전도부띠가 생기기 시작하는 0.5% 인장변형의 값에서 불연속점을 가졌다. 실온의 문턱전류밀도는 이 0.4-0.5% 인장변형 부근에서 극대가 되고, 양쪽으로 변형값이 달라지면서 감소하였다가 극소점을 거쳐 다시 약간 증가하는 모습을 보였는데, 이는 실험결과와 대체로 일치한다. 이 계산결과를 변형의 효과에 관한 다른 여러 이론적 혹은 실험적인 논문들과 비교 토론하였다.

• 한국산업보건학회지
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• 제19권2호
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• pp.102-112
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• 2009

The greatest concern of vapor/gas respirators is when to exchange chemical cartridges, but it is very difficult to estimate the breakthrough time of them in the workplace spot due to so many factors influencing on breakthrough. There needs to study on estimating cartridge exchange period available practically in the spot, even if it is not precise. In the previous study, authors suggested the method on estimating service-life of chemical cartridges using cartridges discarded after use. This followed study was to estimate exchange period for chemical cartridges using comparison of concentrations between Korean Occupational Exposure Limits (KOELs) and odor thresholds of chemicals. Chemicals were divided into four groups, I, II, III and IV groups. Group I chemicals are relatively safe if cartridges are just or slightly delayed exchanged when smelling since odor thresholds were less than 0.5 times KOELs. Odor threshold of Group II chemicals are 0.5~2.0 times KOELs and potentially hazardous if cartridges are exchanged when smelling. Those chemicals should be conducted program on estimating service-life of cartridges, which was just previously published (J Kor Soc Occup Environ Hyg 2008;18(3) 204-215). Group III chemicals (odor thresholds are more than 2.0 times KOELs) and Group IV chemicals (odorless or no data for smelling) must be performed the above mentioned program before cartridges. Even if this method on cartridge exchange using odor threshold is practically widely used in the workplace spot in the present, program on estimating service-life of cartridges is recommended for all chemicals to reduce potentially hazards.

• Journal of applied mathematics & informatics
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• 제5권2호
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• pp.449-456
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• 1998

In this paper a new type of t-operators with double threshold a,b,$\in$(0,1). a$\leq$b, is presented, each pair (t-norm, t-conorm) consisting of two dual elements with respect to a negation with double threshold.

• The Korean Journal of Physiology and Pharmacology
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• 제8권5호
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• pp.281-288
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• 2004

The present study was undertaken to confirm whether melittin, a major constituent of whole bee venom (WBV), had the ability to produce the same nociceptive responses as those induced by WBV. In the behavioral experiment, changes in mechanical threshold, flinching behaviors and paw thickness (edema) were measured after intraplantar (i.pl.) injection of WBV (0.1 mg & 0.3 mg/paw) and melittin (0.05 mg & 0.15 mg/paw), and intrathecal (i.t.) injection of melittin $(6{\mu}g)$. Also studied were the effects of i.p. (2 mg & 4 mg/kg), i.t. $(0.2{\mu}g\;&\;0.4{\mu}g)$ or i.pl. (0.3 mg) administration of morphine on melittin-induced pain responses. I.pl. injection of melittin at half the dosage of WBV strongly reduced mechanical threshold, and increased flinchings and paw thickness to a similar extent as those induced by WBV. Melittin- and WBV-induced flinchings and changes in mechanical threshold were dose- dependent and had a rapid onset. Paw thickness increased maximally about 1 hr after melittin and WBV treatment. Time-courses of nociceptive responses induced by melittin and WBV were very similar. Melittin-induced decreases in mechanical threshold and flinchings were suppressed by i.p., i.t. or i.pl. injection of morphine. I.t. administration of melittin $(6{\mu}g)$ reduced mechanical threshold of peripheral receptive field and induced flinching behaviors, but did not cause any increase in paw thickness. In the electrophysiological study, i.pl. injection of melittin increased discharge rates of dorsal horn neurons only with C fiber inputs from the peripheral receptive field, which were almost completely blocked by topical application of lidocaine to the sciatic nerve. These findings suggest that pain behaviors induced by WBV are mediated by melittin-induced activation of C afferent fiber, that the melittin-induced pain model is a very useful model for the study of pain, and that melittin-induced nociceptive responses are sensitive to the widely used analgesics, morphine.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.527-530
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• 2009

We report on the fabrication of ZnO-based dual gate (DG) thin-film transistors (TFTs) with 20 nm-thick $Al_2O_3$ for both top and bottom dielectrics, which were deposited by atomic layer deposition on glass substrates at $200^{\circ}C$. Whether top or bottom gate is biased for sweep, our TFT almost symmetrically operates under a low voltage of 5 V showing a field mobility of ~0.4 $cm^2/V{\cdot}s$ along with the on/off ratio of $5{\times}10^4$. The threshold voltage of our DG TFT was systematically controlled from 0.5 to 2.0 V by varying counter gate input from +5 to -2 V.

• 농촌의학ㆍ지역보건
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• 제25권2호
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• pp.293-302
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• 2000

본 연구는 코호트내 환자-대조군 연구설계를 통하여 0.5% 소금물에 대한 역치와 위암발생 위험의 관련성을 구명하고자 수행되었다. 강화 코호트와 강화 암등록사업을 통하여 얻은 위암 환자군 90명, 지역사회대조군 141명을 대상으로 수집된 자료를 분석한 결과 두군간에 건강관련 변수들의 분포에 별 차이가 없었다. 다만 '주관적 건강수준'과 '동년배에 비교한 주관적 건강수준'에 차이가 있었다. Cox외 비례위험모형을 이용하여 '주관적 건강수준' 흡연, BMI 등 혼란변수를 통제하고 추정한 '0.5% 소금물을 싱겁다'고 느낀 군의 '그렇지 않다'고 느낀 군에 비한 위암의 상대위험도는 0.77로 통계적으로 유의한 수준이 아니었다(표4). 앞으로 이 분야에 대한 연구는 소금섭취량 측정수준의 상향조정은 물론, 매운 음식 섭취의 감안과 이 두변수의 교호작용등을 고려하되 환자 본인에게서 자료를 얻을 수 있는 병원내에서 수행하는 환자-대조군 연구를 수행함이 바람직하다고 생각한다.

• Ecology and Resilient Infrastructure
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• 제9권2호
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• pp.100-106
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• 2022

섬진강 수계 210개 지방하천을 대상으로 하천연장과 보 밀도 대비 어류 출현종 현황을 분석하였다. 하천연장에 따른 어류 출현종수는 비선형지수함수 (Nonlinear exponential relationship) 관계를 보였다. 모델에 따른 계수값 (b)은 0.03이며, 결정계수(R²)은 약 59.0%인 것으로 나타났다. 모델식에 따른 예측기대종수는 실제 출현종수와 차이를 보였으며, 대상하천 가운데 약 110개 하천 (약 52.4%)에서 실제 출현종수는 예측기대종수보다 낮게 나타났다. 한편 섬진강 수계 하천에서 나타난 평균 보 밀도는 약 2.7개/km였으며, 이는 타 수계 하천과 비교시 월등히 높은 수치였다. 보 밀도 지표 (Index of Weir's Density, IWD)에 따른 어류출현종수간의 2-DKS 분석 결과 어류 다양성에 영향을 주는 보 밀도 역치값 (Threshold value)은 약 2.5개/km인 것으로 나타났다 (D_max=0.048, p<0.05). 실제 보 밀도 지표가 역치값 이상인 경우 어류 출현종수 대비 기대 종수비율은 70% 미만으로 낮아졌다. 따라서, 향후 수생태계 연속성 확보를 위한 보 밀도는 역치값 이하로 관리하는 것이 필요하다.

• Journal of Nutrition and Health
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• 제30권8호
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• pp.995-1008
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• 1997

This study was performed to investigate the change in taste perception during aging and its effects on dietary intake in Korean elderly. The subjects were female aged 65 through 90 in the Anyang area, and college women were included as a comparison group . Dietary intake of the elderly(n=155) and young subjects (n=38) was measured by a 3 day diet record. The taste threshold and 'just right' concentrations(JRC) for sweet and salty tastes were assessed by sensory evaluation . Sucrose solution (0.0.,0.4,0.6,0.8,1.0, 1.2%) and salt solution(0, 0.02, 0.03,0.06,0.09,0.12,0.15%) were used to establish thresholds. for JRC assessment, four suprathreshold sucrose concentrations of 5, 8, 11 and 14% in orange-pineapple flavored juice and salt concentrations of 0.20, 0.34, 0.50and 0.75% in beef stock were prepared. Mean intakes of energy, protein , vitamin A, thiamin , riboflavin, niacin ,calcium and iron of the elderly were below the Korean Recommended Dietary allowances. The elderly showed higher taste thresholds than young subjects of both sweet and salty tastes consumed less calories. Needs to bespecified. The older subjects having high threshold or JRCs for sweet and salty tastes consumed fewer calories from protein and fat. Pearson correlation coefficients was between JRC for sweet and salty tastes 0.54(p<0.01). The correlation coefficients between tastes threshold and nutrient intakes were very low for both age groups. Unlike the college women, in the elderly the JRC of sweet taste of the orange-pineapple juice were negatively correlated with intakes of energy, protein, fats, thiamin , riboflavin , niacin ,vitamin C , iron and consumption of meat and egg food groups (p<0.01). In summation age-related alterations in sweet and salty taste perception were observed in the elderly and dietary intakes of the elderly see to be influenced by these taste perception changes.

• 식물병연구
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• 제16권3호
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• pp.285-289
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• 2010

호박 흰가루병의 수량감수 모델, 요방제 수준 및 경제적 방제수준을 산출하기 위하여 2008년부터 2년간 포장에서 시험하였다. 호박 흰가루병은 정식 후 50일경인 6월 하순에 발생하기 시작하여 7월 하순~8월 상순에 가장 심하였고, 그 이후 감소하는 경향을 보였다. 흰가루병의 발병정도와 수확 과실수, 과실의 생체중, 수량(생체중$\times$수확 과실수)간에는 고도의 부의 상관이 있었고 생체중과 상품과율은 정의 상관을 보였다. 흰가루병의 발병수준(X)에 따른 호박의 수량(Y) 추정 단순직선회귀식은 Y = -10.399X + 6607.5였고 결정계수($R^2$)는 0.9700으로 모델의 적합도가 매우 높았다. 방제비용을 고려하지 않은 흰 가루병의 요방제 수준은 병반면적율 6.5%였으며, 방제비용을 정당화 시킬 수 있는 경제적 피해수준은 병반면적율 21.6%였고, 농가에서 실제로 적용 가능한 경제적 방제수준은 병반면적율 17.3%로 산출되었다.

• 대한가정학회지
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• 제32권5호
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• pp.143-152
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• 1994

To investigate the changes of taste perception by aging, sixty one healthy elderly people and sixty five young adults were participated in the study. Most preferred levels of salt sour and sweet taste were chosen in bean sprout soup radish salad and yaksing respectively. Threshold levels of each taste were also chosen in NaCl solution for salt taste in citric acid solution for sour taste and in sucrose solution for salt taste, in citric acid solution for sour taste and in sucrose solution for sweet taste. The results are as follow: 1.Most preferred salt concentration in bean sprout soup was significantly higher in the elderly than in the young adults(p$\leq$0.001). There was no difference in sour taste preference of radish salad in both age groups. Most preferred sweetness in yacksig was significantly higher in both elderly men and women(p$\leq$0.001) 2. Threshold levels of salt and sweet taste were significantly higher in the elderly (p$\leq$0.001) However there was no difference in threshold level of sour taste in both age groups.