• Journal of Preventive Medicine and Public Health
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• 제46권3호
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• pp.134-138
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• 2013

This road map aims to establish a stable and integrated healthcare system for the Korean Peninsula by improving health conditions and building a foundation for healthcare in North Korea through a series of effective healthcare programs. With a basic time frame extending from the present in stages towards unification, the roadmap is composed of four successive phases. The first and second phases, each expected to last five years, respectively, focus on disease treatment and nutritional treatment. These phases would thereby safeguard the health of the most vulnerable populations in North Korea, while fulfilling the basic health needs of other groups by modernizing existing medical facilities. Based on the gains of the first two phases, the third phase, for ten years, would prepare for unification of the Koreas by promoting the health of all the North Korean people and improving basic infrastructural elements such as health workforce capacity and medical institutions. The fourth phase, assuming that unification will take place, provides fundamental principles and directions for establishing an integrated healthcare system across the Korean Peninsula. We are hoping to increase the consistency of the program and overcome several existing concerns of the current program with this roadmap.

• 대한화학회지
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• 제42권6호
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• pp.679-695
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• 1998

A series of ${\alpha}{\omega}-bis[4-(4'-(S)-(+)-2-methylbutylbiphenyl-4-carboxy)phenoxy]alkanes$, were synthesized, and their thermal and liquid crystalline properties were studied. The chain length of the central polymethylene spacers, x, of the chiral twin compounds was varied from 3 to 12. These compounds were characterized by elemental analysis, IR and NMR spectroscopy, differential thermal analysis (DSC), and crosspolarized microscopy. All compounds were found to be enantiotropic liquid crystalline, and the values of melting $(T_m)$ and isotropization temperature $(T_i)$ as well as ${\delta}H_I$ and ${\delta}S_I$ decreased in a zig-zag fashion, revealing the so called odd-even effect as x increased. Their mesomorphic properties fell into four categories depending upon x; (a) compounds with x=3, 4 and 5 formed only a cholesteric phase on heating, while on cooling they went through two transitions of isotropic (I)-to-cholesteric (Ch) and Ch-to-smectic $A\;(S_A)$ phases before crystallization. (b) compounds with x=6, 8 and 10 exhibited only a cholesteric phase both on heating and on cooling. (c) compounds with x=7 and 9 went through three transitions of crystal $(C)-to-S_A,\;S_A-to-Ch,$ and Ch-to-I phases on heating while on cooling they went through four transitions of I-to-Ch, $Ch-to-S_A,\;S_A-to-Smectic\;C\;(S_C),\;and\;S_c-to-C$ phases in that order, and (d) compounds with x=11 and 12 went reversibly through four transitions of $C-to-S_C,\;S_C-to-S_A,\;S_A-to-Ch,$ and Ch-to-I phases.

• 한국운동역학회지
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• 제27권2호
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• pp.125-132
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• 2017

Objective: The aim of this study was to investigate the effect of targeted knee flexion angle on biomechanical factors of knee joint between upward and downward phases during the forward lunge. Method: Eight elderly subjects (age: $22.23{\pm}1.51years$, weight: $69{\pm}6.63kg$, height: $174.88{\pm}6.85cm$) participated in this study. All reflective marker data and ground reaction force during a forward lunge were collected. The knee joint movement and reaction force and joint moment at maximum knee flexion angle were compared by repeated measures one-way analysis of variance (ANOVA) (p<.05). The peak knee joint reaction force and joint moment between upward and downward phases were compared by repeated measures two-way ANOVA (p<.05). Results: The anterior and vertical knee joint movements, reaction force, and extensor moment of $80^{\circ}$ targeted knee flexion condition at maximum knee flexion angle was greater than both $90^{\circ}$ and $100^{\circ}$ conditions (p<.05). The $80^{\circ}$ knee flexed angle condition had greater peak joint reaction force and extensor moment compared with both $90^{\circ}$ and $100^{\circ}$ conditions between upward and downward phases during the forward lunge. Conclusion: As the targeted knee joint flexion angle increases, knee joint movement and kinetic variables become greater during the forward lunge exercise.

• 한국재료학회지
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• 제27권10호
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• pp.563-568
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• 2017

In this study, the coating of an Al-Cr layer on the surface of a Zircaloy-4 alloy was carried out through plasma pretreatment coating and a laser surface melting process. Two different conditions for laser treatment, severe or minimal surface melting of the Zr alloy substrate, were applied to form the final coating. When there was significant surface melting of the Zr alloy, the solidification microstructure of the newly formed coating layer was mainly composed of needle-shaped $Al_3Zr$, Al(Cr) and $Al_7Cr$ phases. On the other hand, the solidification microstructure of the coating layer was mainly composed of Al(Cr) and $Al_7Cr$ phases when there was minimal surface melting of Zr base in the laser process. However, when the coating was maintained at $1100^{\circ}C$ for 2 hours, significant inter-diffusion occurred between the phases in the coating. As a result, the upper part of the coating layer was observed to mainly consist of $Al_3Zr$ and $Al_8Cr_5$ phases, regardless of the laser treatment conditions.

• Applied Microscopy
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• 제31권2호
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• pp.129-141
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• 2001

식충목 땃쥐과 쇠뒤쥐 (Sarex minutus gracillimus)의 정자변태과정을 알아보기 위하여 세정관 상피의 세포분화에 따른 형태적 특징을 조사하여 다음과 같은 결과를 얻었다. 쇠뒤쥐의 정자변태과정을 골지기, 두모기를 각각 전 중 후기로, 첨체기를 각각 전 후기로, 성숙기와 이탈기를 각각 하나의 단계로 총 10단계로 나눌 수 있었다. 핵질의 응축은 첨체기에 시작하여 이탈기에 완성되었으며, 만세트의 출현은 첨체후기부터 성숙기까지 나타났다. 정자편모의 형성은 골지후기에 생성하여 이탈기에 완성되었다. 다포체는 골지기부터 성숙기까지 나타났으며, 골지기는 주로 pale multivesicular body가, 두모기와 첨체기는 주로 pale 또는 moderate pale multivesicular bodies가 그리고 성숙기에서는 dense multivesicular body가 관찰되었다.

• Applied Microscopy
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• 제22권2호
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• pp.97-117
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• 1992

In order to study process of spermiogenesis of the Korean greater horseshoe bat, Rhinolophus ferrumequinum korai, the cycle of seminiferous epithelium was examined by the light and electron microscope and the following results were obtained based on the epithelial cell differentiation. 1. Spermiogenesis occurred from early July to mid-Octber, and spermatogenic activity was vigorous from mid-August to late September. Spermatocytes including spermatogonia were found to be degenerated in only July. It is deduced that the degeneration serves as the mechanism to regulate effective use of energy to prepare for mating and hibernating periods, and regulation of breeding cycle. 2. Spermiogenesis of the Korean greater horseshoe bat was divided according to differentiation of the cell structure, into Golgi, cap, acrosome, maturation and spermiation phases; Golgi, cap and spermiation phases were further divided into two steps of early and late phase respectively, and acrosome phase into three steps of early, mid and late phases, and maturation phase has only one step. Hence, the spermiogenesis consists of ten phases. The first research was done in this article on the changes of chromatin with nucleus, the time of appearance and disappearance of chromatin granules, in case of Korean greater horseshoe bat (Rhinolophus ferrumequinum korai). Chromatin granule began to be condensed in late Golgi and the condensation proceeded to form an irregular mass of a electron-dense chromatin in a form of circular cylinder in the center of nucleus at the phase of maturation. Finally, the chromatin condensation proceeded and perfect nucleus of sperm with homogeneous density was formed when the sperm was separated from Sertoli cell. Therefore, appearance and disappearance of chromatin granules occurred in the period of time between late Golgi and maturation phase, The tail of sperm began to develop in early cap phase, Numerous lipid droplets were obseved in the cytoplasm of spermatids during the maturation phase, which seemed to be used as energy source necessary to make mature sperm during spermiogenesis.

• 원예과학기술지
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• 제32권5호
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• pp.710-720
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• 2014

Movements of the upper and lower limb muscles during five common gardening tasks were analyzed by using electromyography (EMG). Twenty adults aged in their twenties (mean age, $24.8{\pm}2.4$ years) were recruited. On two separate occasions, subjects visited a garden plot to perform digging, raking, troweling, weeding, and hoeing; all tasks were performed three times with 20 s intervals for each trial. To measure muscle activation during the five gardening tasks, surface EMG was used. Bipolar surface EMG electrodes were attached to eight upper limb muscles (bilateral anterior deltoid, biceps brachialis, brachioradialis, and flexor carpi ulnaris) or eight lower limb muscles (bilateral vastus lateralis, vastus medialis, biceps femoris, and gastrocnemius) on both sides of the body, for a total of 16 muscles. During the five tasks, photographs were taken of movement phases using a digital video camera. The right flexor carpi ulnaris and brachioradialis showed higher activation than the other upper and lower limb muscles measured during the tasks. All 16 upper and lower limb muscles were actively used only during digging. According to movement analysis of each activity, digging was classified into four movement phases, whereas raking, troweling, weeding, and hoeing each were divided into three movement phases. In each activity, there were high-impact phases in terms of muscle activation; the flexor carpi ulnaris and brachioradialis were identified as major muscles in each impact phase. This analysis may be used to generate biomechanical profiles of gardening tasks for practitioners when designing efficient gardening interventions for physical health or rehabilitation.

• 한국전자파학회논문지
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• 제18권1호
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• pp.53-61
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• 2007

이 논문은 직교 주파수 다중 전송 통신 방식의 첨두대 평균 전력비를 줄이기 위하여 대역폭과 전력의 효율성을 고려하여 파일롯과 데이터 심볼에 회전 위상을 중첩한 기법에 대한 연구 논문이다. 즉 파일롯 심볼에 위상 회전 벡터를 부가하여 파일롯 심볼 사이의 데이터 심볼의 위상 회전 벡터를 파일롯 심볼의 위상 회전 벡터와 동일하게 하여 전송하는 기법이다. 이러한 방식에 따라 송신기는 부분 분할 전송 기법에 의한 첨두대 평균 전력비를 줄일 수 있고 수신기에서 위상 회전 벡터를 파일롯 심볼의 채널 추정에 의하여 원래의 데이터 심볼을 복원할 수 있다. 따라서 송신기에서는 별도의 부반송파를 첨두대 평균 전력비의 저감하는 용도로 사용하지 않음으로써 효율적인 대역폭의 운용이 가능하고 수신기에서 위상 회전 벡터에 대한 부가적인 전송에 따른 오류에 의한 비트 오율의 급격한 증가를 방지할 수 있다. 다시 말해서 대역폭과 전력 및 통신 성능을 모두 개선할 수 있는 방법이라 할 수 있다.

• Nuclear Engineering and Technology
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• 제49권5호
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• pp.989-995
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• 2017

Distributed Control System (DCS) communication networks, which use Fast Ethernet with redundant networks for the transmission of information, have been installed in digitalized nuclear power plants. Normally, failover tests are performed to verify the reliability of redundant networks during design and manufacturing phases; however, systematic integrity tests of DCS networks cannot be fully performed during these phases because all relevant equipment is not installed completely during these two phases. In additions, practical verification tests are insufficient, and there is a need to test the actual failover function of DCS redundant networks in the target environment. The purpose of this study is to verify that the failover functions works correctly in certain abnormal conditions during installation and commissioning phase and identify the influence of network failover on the entire DCS. To quantify the effects of network failover in the DCS, the packets (Protocol Data Units) must be collected and resource usage of the system has to be monitored and analyzed. This study introduces the use of a new methodology for verification of DCS network failover during the installation and commissioning phases. This study is expected to provide insight into verification methodology and the failover effects from DCS redundant networks. It also provides test results of network performance from DCS network failover in digitalized domestic nuclear power plants (NPPs).

• 한국재료학회지
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• 제31권3호
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• pp.156-161
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• 2021

Cr-Si based alloys are not only excellent in corrosion resistance at high temperatures, but also have good wear resistance due to the formation of Cr3Si phase, therefore they are promising as metallic coating materials. Aluminum is often added to Cr-Si alloys to improve the oxidation resistance through which stable alumina surface film is formed. On the other hand, due to the addition of aluminum, various Al-containing phases may be formed and may negatively affect the heat resistance of the Cr-Si-Al alloys, so detailed investigation is required. In this study, two Cr-Si-Al alloys (high-Si & high-Al) were prepared in the form of cast ingots through a vacuum arc melting process and the microstructural changes after high temperature heating process were investigated. In the case of the cast high-Si alloy, a considerable amount of Cr3Si phase was formed, and its hardness was significantly higher than that of the cast high-Al alloy. Also, Al-rich phases (with the high Al/Cr ratio) were not found much compared to the high-Al alloy. Meanwhile, it was observed that the amount of the Al-rich phases reduced by the annealing heat treatment for both alloys. In the case of the high temperature heating at 1,400 ℃, no significant microstructural change was observed in the high Si alloy, but a little more coarse and segregated AlCr phases were found in the high Al alloy compared to the cast state.