• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1996년도 The 9th KACG Technical Annual Meeting and the 3rd Korea-Japan EMGS (Electronic Materials Growth Symposium)
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• pp.422-448
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• 1996

Low-temperature epitaxial growth of Si and SiGe layers of Si is one of the important processes for the fabrication of the high-speed Si-based heterostructure devices such as heterojunction bipolar transistors. Low-temperature growth ensures the abrupt compositional and doping concentration profiles for future novel devices. Especially in SiGe epitaxy, low-temperature growth is a prerequisite for two-dimensional growth mode for the growth of thin, uniform layers. UHV-ECRCVD is a new growth technique for Si and SiGe epilayers and it is possible to grow epilayers at even lower temperatures than conventional CVD's. SiH and GeH and dopant gases are dissociated by an ECR plasma in an ultrahigh vacuum growth chamber. In situ hydrogen plasma cleaning of the Si native oxide before the epitaxial growth is successfully developed in UHV-ECRCVD. Structural quality of the epilayers are examined by reflection high energy electron diffraction, transmission electron microscopy, Nomarski microscope and atomic force microscope. Device-quality Si and SiGe epilayers are successfully grown at temperatures lower than 600℃ after proper optimization of process parameters such as temperature, total pressure, partial pressures of input gases, plasma power, and substrate dc bias. Dopant incorporation and activation for B in Si and SiGe are studied by secondary ion mass spectrometry and spreading resistance profilometry. Silicon p-n homojunction diodes are fabricated from in situ doped Si layers. I-V characteristics of the diodes shows that the ideality factor is 1.2, implying that the low-temperature silicon epilayers grown by UHV-ECRCVD is truly of device-quality.

• Natural Product Sciences
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• 제5권1호
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• pp.25-32
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• 1999

The pharmacological actions of ambrein were investigated alone or in combination as a pretreatment with agonists (adrenaline, noradrenaline, acetylcholine, histamine, nicotine), antagonists (atropine, atenolol) and calcium channel blocker (verapamil) in vivo in anaesthetized SWR rats using blood pressure, heart rate and myocardial contractility as parameters. Ambrein in the dose range of 50-200 mg/kg to the normotensive anaesthetized rats demonstrated negative chronotropic effect and increased the myocardial contractility significantly. At the mid dose (100 mg/kg) this increase in contractile force was 36% and 44% above the normal at 30 min and 60 min intervals post-treatment, respectively. Both of the lower and high doses (50 mg/kg and 200 mg/kg) had similar effects. Furthermore, this contractile response was dose related. Also, this compound produced a considerable increase in myocardial contractility when used as a pretreatment with some agonists and antagonists. The results on blood pressure did not show a considerable change when ambrein was used alone. However, ambrein pretreatment at the dose of 100 mg/kg did not block the effects of adrenaline, noradrenaline, isoprenaline and acetylcholine on heart rate and blood pressure. On the other hand, this pretreatment attenuated the sympathoadrenal effects of nicotine significantly. Chronotropic and blood pressure changes produced by histamine were also inhibited by ambrein pretreatment. This pretreatment significantly reversed the effects of atenolol but failed to demonstrate any change in the negative chronotropic, inotropic and hypotensive responses induced by verapamil. It is concluded that ambrein induced nonselective dose dependent antagonism of the effects of some agonists and antagonists require contribution of some neuromediators. However, the positive isotropic effects of ambrein possibly involve the enhancement of slow Ca channels and/or activation of ${\beta}-adrenergic$ receptors in the heart. At this moment it is difficult to explain the exact mode of action of ambrein and the studies dealing with Ca channel blocker and adrenergic blocker followed by ambrein may help to define the factors which contribute to its positive inotropic effects.

• 한국컴퓨터정보학회논문지
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• 제16권10호
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• pp.229-239
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• 2011

본 연구는현재 각지역에서 시행되고 있는 우리나라의 지역문화축제가 관주도의 연례행사로서 이루어지는 폐해를 극복하고 지역주민의 자발적인 참여를 이끌어내고 보다 효과적인 홍보와 마케팅을 연계한 외부 관광객의 참여를 유도하여 지역문화의 구심점이 될 수 있는 지역문화축제의 수익성 모델을 제시하고자 한다. 축제는 그 이름만으로 매력적이고 사람들에게 흥겨움과 호기심을 불어넣을 수 있지만, 축제행사가 일회성이 아닌 지속적인 행사로 유지 확대 발전하기 위해서는 수요자 중심의 서비스 품질에 도달할 수 있는 노력이 절대적으로 필요하다. 현재 우리나라 각 지역에서 많은 위험(리스크)을 안고서도 집행될 수밖에 없는 지역축제의 서비스 특성을 고려하여 수익 창출을 실현하는 수익성 모형을 개발하여 그 활성화 방안을 제시하는데 그 목적을 두고 있다. 이를 위하여 기존 연구와 자료 및 전문가의 의견을 바탕으로 다중회귀분석을 통하여 분석하였다.

• Nuclear Engineering and Technology
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• 제48권3호
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• pp.765-772
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• 2016

In analyzing residual radiation, researchers generally use a two-step Monte Carlo (MC) simulation. The first step (MC1) simulates neutron transport, and the second step (MC2) transports the decay photons emitted from the activated materials. In this process, the stochastic uncertainty estimated by the MC2 appears only as a final result, but it is underestimated because the stochastic error generated in MC1 cannot be directly included in MC2. Hence, estimating the true stochastic uncertainty requires quantifying the propagation degree of the stochastic error in MC1. The brute force technique is a straightforward method to estimate the true uncertainty. However, it is a costly method to obtain reliable results. Another method, called the adjoint-based method, can reduce the computational time needed to evaluate the true uncertainty; however, there are limitations. To address those limitations, we propose a new strategy to estimate uncertainty propagation without any additional calculations in two-step MC simulations. To verify the proposed method, we applied it to activation benchmark problems and compared the results with those of previous methods. The results show that the proposed method increases the applicability and user-friendliness preserving accuracy in quantifying uncertainty propagation. We expect that the proposed strategy will contribute to efficient and accurate two-step MC calculations.

• 한국컴퓨터산업학회논문지
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• 제7권1호
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• pp.23-32
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• 2006

컴퓨터와 네트워크를 활용한 사이버 강좌는 언제 어디서나 학습할 수 있고 빠른 피드백, 역동적인 학습형태를 이루어 낼 수 있는 장점이 있어 활발한 연구가 진행되고 있다. 그러나 대부분의 연구들은 사이버 대학의 운영 현황의 문제점, 사례연구, 활성화 연구에 초점을 두고 있어 학습의 주체자인 학습자들에 대한 요구사항을 반영한 연구는 미비한 상태이다. <중략> 설문 분석 결과, 이들이 선호하는 콘텐츠 유형은 텍스트+이미지+동영상이라는 것을 알 수 있었으며 불만 사항으로는 학습난이도, 강의분량, 시스템접속, 출석 등이 있는 것으로 분석되었다. 이러한 불만 요소를 제거하기 위해 개선 방안을 수립하여 이를 새로운 사이버 강좌에 반영한 후 학업 성취도를 검증한 결과 전체 평균 17.3점이 향상되어 매우 높은 학업 성취도를 보여주었다. 이러한 성취도결과는 교수자의 관점에서 교수설계도 중요하지만 학습자의 관점에서도 교수 설계도 필요하다는 것을 의미한다.

• 한국축산식품학회지
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• 제32권5호
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• pp.598-603
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• 2012

Beef qualities which can be properly predicted by time-temperature integrator (TTI), a chromatic indicator, were selected in terms of its similarity of temperature dependence between beef qualities and TTI, denoted by Arrhenius activation energy ($E_a$). The high similarity is required to afford accurate prediction. A devised enzymatic TTI based on laccase (an oxidase), which catalyses the oxidation on 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) producing color development, was applied. The factors of beef quality, such as volatile basic nitrogen (VBN), pH, color (CIE $L^*$, $a^*$), Warner-Bratzler shear force (WBSF), Pseudomonas spp. count, and lactic acid bacteria (LAB) count were considered for the selection. $E_a$ (55.48 kJ/mol) of the TTI was found to be similar to those of the beef qualities (all referred) in the order of LAB count (53.54 kJ/mol), CIE $a^*$ value (61.86 kJ/mol), pH (65.51 kJ/mol), Pseudomonas spp. Count (44.54 kJ/mol), VBN (67.98 kJ/mol), WBSF (40.67 kJ/mol), and CIE $L^*$ value (33.72 kJ/mol). The beef qualities with more similar $E_a$ to that of the TTI showed less difference between real and TTI predicted levels. In conclusion, it was found out that when applying TTI to food packages, their $E_a$ similarity should be checked to assure accurate estimation of food quality levels from TTI response.

• 기술혁신연구
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• 제14권3호
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• pp.209-235
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• 2006

Since the end of the cold war, technical tie-up between private corporations and an army in developed countries has increased a lot, and the trend is spreading through developing countries rapidly. To cope with the circumstance actively, the dual use technology program for both private corporations and an army was begun in Korea in 1998. With the program, overlapping investment was resolved and technology transfer was stimulated. And the standardization and information exchange saved considerable national budget and made possible economic profit. Yet, the combination project of 4 ministries and offices showed problems such as loose cooperation and, low industralization record. However, developed countries are out of the mere stage of dual technology development and turn into broad technical tie-up including future prediction, national competitiveness improvement, and the private company's leading participation and they are systemizing them very fast. Korea also set up the national defense reform plan with the blueprint of future military force improvement, budget increase for national defense research, and increased participation of private corporations, and created Defense Acquisition program Administration to support them. The innovation of national defense system brings forward the need to link the private and military innovation. Korea has pursued the fast growth through assimilation, absorption, and improvement of foreign technology. But now, Korea has to focus on self innovation, original technology, parts and material. As this applies to private companies and military equally, it is important to concentrate limited resources for the effective technology cooperation. Considering this, the strategies to activate the dual use technology are program concept and range extension, task-deduction way improvement and future-oriented common task deduction, and promotion system improvement.

• Journal of Biosystems Engineering
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• 제36권3호
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• pp.223-230
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• 2011

Physiological signals such as body temperature, heart rate, blood pressure and heart rate variability and biomechanical workload for stress analysis were investigated during the cherry tomato harvesting work in a greenhouse. The skin temperatures raised $0.05^{\circ}C$/min, $0.03^{\circ}C$/ min, and $0.08^{\circ}C$/min in standing, stooping and squatting postures, respectively. Breath rate significantly increased from 18 to 28 breaths/min during the cherry tomato harvesting work. As the heart rate during the work ranged from about 72 to 110 beats/min (bpm), the cherry tomato harvesting work appeared to be a light intensity task of less than 110 bpm. The worker's average energy consumption rate in three positions during 43 min working time was 65.74 kcal (91 kcal/h in 70 kg). This was a light intensity of work, compared to 75 kcal/h in 70 kg of basic metabolic energy consumption rate of a worker with 70 kg weight; The maximum shear force on the disk (L5/ S1) due to static workload in the cherry tomato harvesting work was 446 N in the stooping posture, 321 N in the squatting posture and 287 N in the standing posture. Acute stress index expressed with the heart rate variability, increased parasympathetic activation up to about 70 while workers were doing most agricultural work in this study. This study provided a system to measure quantitatively workers' physiological change, kinematics and kinetic factors without any restrictions of space in the greenhouse works.

• 한국세라믹학회지
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• 제39권7호
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• pp.635-641
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• 2002

고온 프로톤전도체인 $Y_2O_3$가 도핑된 $SrZrO_3$에 대하여 전기전도도의 가스 분위기 및 온도 의존도를 impedance spectroscopy로 측정하였다. 수소의 용해는 산소가 공존할 때 더 큰 열역학적 추진력을 갖게 되어 결과적으로 수증기 형태로 결정 속으로 유입되며, 프로톤전도도는 ${P_w}^{1/2}$ (수증기분압)에 의존하여 증가하였다. 순수 수소 분위기에서의 수소의 용해반응 $H_2(g)=2H_{i}$ +2e'은 전자가 산소이온공공에 trapping됨에 따른 열역학적 활동도의 감소에 의해 반응의 추진력이 커지며 그 결과 저온에서는 아르곤 분위기에서 보다 높은 전기전도도를 나타내었다. 전기전도도의 활성화에너지는 $600~900^{\circ}C$ 온도범위의 아르곤분위기에서 50kJ/mo1로 문헌에 나타난 프로톤전도도의 그것과 비슷한 크기를 나타냈다. 프로톤전도도의 입계저항은 10% 도핑한 경우 $700^{\circ}C$ 이하의 저온에서 현저하게 나타났다.

• 한국컴퓨터정보학회논문지
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• 제23권6호
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• pp.43-49
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• 2018

In this paper, we propose a taping therapy as effective intervention for patients with the back pain. The purpose of this study is to investigate the effects of taping intervention on the VAS evaluated score and he muscular activation degree among 119 paramedics with musculoskeletal injury. In order to achieve the purpose of the study, data was collected from 15 paramediecs in the paramedics department of 3 fire stations under J city's fire defense headquarters. The following results can be obtained by measuring the subjective, the back muscle strength and the buckling-anteflexion before and after the taping for 15 119 paramedics. Through the verification experiment of taping effect to paramedics during the stretcher lifting in this study the VAS evaluated score for the backache are $1.67{\pm}0.62$ before and $0.80{\pm}0.68$ after the application of taping which show statistically significant decrease(p<0.05). In the experimentof joint operation range the measured buckling anteflexion length are $14.62cm{\pm}4.89$ before and $16.41cm{\pm}4.11cm$ after the application of taping which show statistically meaningful difference(p<0.05). In the comparison of muscle activity about paramedics erector spinae(ES) shows the meaningful decrease and external obliques(EO) displays the significant increase. Erector spinae(ES) and internal obliques(IO) show the increasing trend in the muscle activity although they are not significant. the muscle activity for the erector spinae is lowered so that the contribution to the force required for the extensor during the stretcher lifting is resultingly reduced to have the effects of enhancing the activity of abdominal muscles.