• 한국산학기술학회논문지
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• 제16권10호
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• pp.6977-6984
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• 2015

품질 향상을 위해 연속적인 소성 변형을 이용한 롤 포밍 공정에 피어싱, 벤딩, 트리밍 등 별도의 가공공정을 통합한 볼 슬라이드 레일의 멀티 롤 포밍 공정의 필요성이 대두되고 있다. 하지만 프레스기의 진동 및 소음은 이 공정에서 생산되는 슬라이드 레일의 품질 저하를 유발한다. 본 연구에서는 롤 포밍 유한요소 프로그램으로 최적 변형률을 고려하여 롤을 설계하였다. 그리고 멀티 공정의 정적 안정성을 예측하기 위해 구조해석 프로그램으로 프레스기에 대한 응력 및 변형량을 계산하였다. 또한 공진영역에서의 장치들의 운전을 회피하기 위해 Modal 해석을 통해 1, 2차 모드에서의 고유진동수를 계산하였다. 그 결과 공정의 동적 안정성 개선을 확인하기 위해 마이크로폰과 가속도계를 이용하여 기존 및 연구 공정들의 소음, 진동의 크기를 비교하였다. 그리고 기존 및 연구 공정으로 생산되어진 레일의 폭 치수와 표면거칠기를 측정하였다. 따라서 해석 및 실험적 연구를 통해 멀티 롤 포밍 공정이 안정하다는 것을 알 수 있었다.

• 한국전문물리치료학회지
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• 제23권1호
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• pp.80-86
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• 2016

Background: Prone hip extension (PHE) can be performed to measure the lumbopelvic motor patterns and motions. Imbalances in lumbopelvic muscle activity and muscle weakness can result in instability including pain in lumbopelvic region. The posterior oblique sling (POS) muscles contribute to dynamic lumbopelvic stability. In addition, POS are anatomically aligned with the trapezius muscle group according to shoulder positions. Objects: This study compared the electromyography (EMG) activity of POS and pelvic compensations during PHE with and without pre-activation of lower trapezius muscle (lowT). Methods: Sixteen healthy males were recruited. PHE was performed in randomized order: PHE with and without lowT pre-activation. Surface EMG signals were recorded for biceps femoris (BF), gluteus maximus (GM) (ipsilateral), lumbar multifidus (MF) (bilateral), and the lowT (contralateral). An electromagnetic tracking motion analysis was used to measure the angle of pelvic rotation and anterior tilting. Results: The ipsilateral GM and bilateral MF EMG amplitudes were greater during PHE with lowT pre-activation compared to PHE without lowT pre-activation (p<.05). The BF amplitude during PHE without lowT pre-activation was significantly greater than that during PHE with lowT pre-activation (p<.05). The angles of pelvic rotation and anterior tilting during PHE with lowT pre-activation were significantly smaller compared to PHE without lowT pre-activation (p<.05). Conclusion: PHE with lowT pre-activation, which is aligned with the POS, showed more increased MF and GM muscular activity with smaller lumbopelvic compensations in rotation and anterior tilting compared to PHE without lowT pre-activation.

• 대한정형도수물리치료학회지
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• 제8권2호
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• pp.57-71
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• 2002

Cervical pain is a rapid increase that is owing to a flexion-extension whiplash injury, unappropriated posture, chronical repetition injury from abdominal position of head and neck, excessive repeating work, chronical deficiency of excercise. Because of that is bring about muscle unbalance, tightness of cervical extensor muscle, weakness of cervical deep flexor muscles, instability of cervical region and reduction of proprioceptive sensor. Recent the role of muscle is more emphasized for preservation of sine stabilization. And cognition of integrated muscular system, importance for the operation and relation is increased to maintain stability of the motor system and pertinent function. Therefore we are going to introduce the sling exercise and stabilization exercise method for advanced efficient of cervical and upper limb and for the muscle strengthening to importance cervical stabilization through neurological program as control the reaction of cervical stabilization. Sling exercise therapy(SET) concept consists of a system of diagnosis and treatment. The system of diagnosis involves testing the muscle's tolerance through progressive loading in open and close kinetic chains. The SET system contains elements such as relaxation, increasing the range of movement, traction, training the stabilizing musculature, sensory-motor exercises, training in open and close kinetic chains, dynamic training of the mobilizing musculature, cardiovascular exercise, group exercise, personal exercise at home Sensory-motor training is an essential element of the SET concept. The emphasis is on closed kinetic chain exercise on an unstable surface, there by achieving optimum stimulation of the sensory-motor apparatus.

• 화약ㆍ발파
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• 제15권3호
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• pp.14-19
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• 1997

Koreans have emphasized education as the primary means to reconstruct our country means to reconstruct our country after two catastrophic events-the Japanese occupation and the Korean War(1950-1953). A Strong belief- in education coupled with sheer deter-mination spurred the period of industrial and eeonomic development that started in the early 1970-'s. The "can-do" attitude of the general public was matched and aided by small S & T communities. Scientists and engineers provided the neeessary expertise to manufacture goods and process the many raw materials imported from overseas. After nearly three decades of reconst-ructing our completely devastated country, Korea has become a modern, cosmo-politan, fast-paced and dynamic country. In order to further increaser our manufac- turing capabilities and double the per-capita income by the beginning of the 21st century, we must improve productivitiy and encourage creatitivity in all sectors of our country. The S & T community's efforts in research and development. education, and interna-tional cooperation will be invaluable in determining our direction and reaching these goals. The general public is eager to peacefully unite our foreign powers since 1945. Toward that end. members of the S & T community are willing to coope-rate with our north Korean counterparts in all areas of S & T with the exception of defense related endeavors. Establi-shing scientific ties with north Korea will result in mutual economic benefit and greater regional stability in East Asia. In particular. scientists and manu-facturers in each province are eager to initiate cordial and professional relation-ships with north Korea in the hopes of securing these benefits. The Korean Federation of Science and Technology Societies(KOFST) has played an important role both in developing S & T policies, and in gostering the frowty of S & T societies. A non-governmental umbrella organization composed of over 251 professional societies, KOFST facili-tates the transfer of research outcomes and technology from research institutions to the various industries. KOFST also seeks to increase cooperation between the countries of the Pacific Rim. As evidence of that, we have pursued joint research and industrial ventures with China. Established projects include those on environmental conditions in the Yellow Sea, and improvement of aircraft manufacturing, telecommunica-tion equipment, and agricultural produ-cts. Increased cooperation between the Pacific Rim countries, particularly in S & T, would foster social and economic development for the region as a whole.

• 한국결정성장학회지
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• 제20권5호
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• pp.232-236
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• 2010

SiC 세라믹스는 가볍고, 우수한 고온 강도 및 온도 안정성을 지니고 있어 고온 구조용 디바이스에 많이 응용되고 있다. 본 논문에서는 분자동역학을 이용하여 다양한 온도에서 SiC 결정의 탄성율 특성을 분석하고자 하였다. 이를 위하여 SiC 결정을 모델링하여 구성 원자 사이에 Tersoff 포텐셜을 적용하고, 분자동역학 프로그램인 LAMMPS S/W를 이용하여 상온부터 $1,250^{\circ}C$까지 응력-변위 거동(stress-strain behavior) 및 탄성율 변화를 분석하였다. 본 연구의 결과, SiC 결정은 잘 알려진 바와 같이 저온에서 탄성변형 특성을 보이지만, $1,000^{\circ}C$ 이상의 고온에서 높은 변위를 인가할 경우, 약간의 소성 변형 특성을 보이는 것으로 나타났다. 또한 상온부터 $1,250^{\circ}C$까지 온도가 증가함에 따라 SiC 결정의 탄성율은 약 475 GPa 부터 425 GPa의 범위에서 변화하는 것으로 분석되었다.

• Biomaterials and Biomechanics in Bioengineering
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• 제2권2호
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• pp.97-109
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• 2015

A series of amphiphilic graft copolymers were synthesized by varying the number of graft chains and graft chain lengths. The polarity of the hydrophobic graft chain on the copolymers was varied their solution properties. The glass transition temperature of the copolymers was in the low-temperature region, because of the amorphous nature of poly (trimethylene carbonate) (PTMC). The surface morphology of the lyophilized colloid gel had a bundle structure, which was derived from the combination of poly(N-hydroxyethylacrylamide)( poly(HEAA)) and PTMC. The solution properties were evaluated using dynamic light scattering and fluorescence measurements. The particle size of the graft copolymers was about 30-300 nm. The graft copolymers with a higher number of repeating units attributed to the TMC (trimethylene carbonate) component and with a lower macromonomer ratio showed high thermal stability. The critical association concentration was estimated to be between $2.2{\times}10^{-3}$ and $8.9{\times}10^{-2}mg/mL$, using the pyrene-based fluorescence probe technique. These results showed that the hydrophobic chain of the graft copolymer having a long PTMC segment had a low polarity, dependent on the number of repeating units of TMC and the macromonomer composition ratio. These results demonstrated that a higher number of repeating units of TMC, with a lower macromonomer composition, was preferable for molecular encapsulation.

• 지역연구
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• 제39권4호
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• pp.53-71
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• 2023

본 연구는 국내 7대 특·광역시를 대상으로 지난 20년(1996~2016년)간의 고용성장에 대한 요인별 기여도를 파악하는 것이 목적이다. 이를 위해 통계청에서 제공하는 사업체 조사 자료를 바탕으로 다요인분해(multifactor partitioning, MFP)분석을 수행하였다. 분석의 주요 결과는 다음과 같다. 첫째, 장기간에 걸친 대도시권의 고용성장에서는 전반적으로 지역효과가 지배적인 영향력을 보이고 있으며, 산업구조효과가 이를 뒤따르고 있다. 동태적 다요인분해분석 결과는 향후 지역 간 고용 격차가 산업구조에 의해 설명될 가능성이 크다는 것을 보여준다. 둘째, 성별과 양질의 일자리구성효과는 지역별 고용성장에 큰 기여를 보이지 않는다. 단, 실질적인 개별 인자들의 기여를 보면 남성-상용근로자의 고용감소와 여성-비상용근로자의 고용성장 패턴을 유추할 수 있다. 이러한 결과는 각 지역 산업의 구조적 전환과 고용안정성이 동반된 질적성장을 도모할 수 있는 고용정책의 중요성과 필요성을 의미한다.

• 사회복지연구
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• 제48권4호
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• pp.59-89
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• 2017

개인 복지태도의 변동성은 해당 사회의 복지태도 양상 및 특성, 이의 정치적 영향 등을 파악함에 있어 주목되어야 할 부분이다. 이러한 점에 입각하여, 본 연구에서는 개인 복지태도의 종단 변화에 대한 분석 및 고찰을 통해 한국사회 복지태도 변화의 양상 및 특성에 대한 이해를 제고하고자 하였다. 본 연구의 분석에는 2010년, 2013년, 2016년도 한국복지패널조사 복지인식 부가조사를 활용하였으며, 개인 복지태도의 변화는 '소득격차해소의 정부책임성', '복지증세' '보편(선별) 복지' 등의 3개 주요 복지태도 항목들에서 지지 상태의 변화 뿐 아니라 다양한 변화 유형들(친복지적 태도 변화와 반복지적인 태도 변화; 미온적인 지지태도 변화와 극적인 지지태도 변화)로 측정, 분석하였다. 분석결과에서는, 복지태도 항목들의 미약한 평균치 변화와는 달리 개인 수준의 지지 태도의 변화는 매우 활발하여, 한국사회에서 개인 복지태도 변화의 역동성을 확인할 수 있었다. 한편, 개인 특성에 따른 복지태도 변화 분포는 복지이슈 및 시기에 따라 상당한 차이를 보여, 복지태도의 변화는 특정 집단에 국한되지 않고 정치사회적 상황 및 이슈에 따라 역동적으로 발생됨을 확인할 수 있었다. 끝으로, 이항 및 다항 로짓 모델들의 분석에서 복지태도 변화는 성별, 연령, 거주지역, 고용지위, 소득계층, 정치이념 등의 다양한 개인 특성과 유의하게 관련된 것으로 나타나, 복지태도 변화에는 계층 및 계급적 이해 뿐 아니라 다양한 측면의 개인적 이해가 개입됨을 확인할 수 있었다. 본 연구 결과는 한국사회에서 개인 수준의 활발한 복지태도의 변화 혹은 역동적 변화를 확인하는 바로, 정태적인 분석 접근에서 벗어나 한국인의 활발한 복지태도 변화에 대한 학술적, 정치적 주목의 필요성을 환기하여 준다.

• Journal of Pharmaceutical Investigation
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• 제41권2호
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• pp.103-109
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• 2011

The objective of the study was to prepare self-microeulsifying drug delivery system (SMEDDS) incorporating atorvastatin calcium and evaluate its properties and oral bioavailability. Solubility of atorvastatin in various vehicles was determined. Pseudo-ternary phase diagrams were constructed to identify the good self-emulsification region. The droplet size distributions of the resultant emulsions were determined by dynamic light scattering measurement. The mean droplet size of chosen formulation (20% ethyl oleate, 40% tween-80, 40% Carbitol$^{(R)}$) was $23.4{\pm}1.3$ nm. The SMEDDS incorporating atorvastatin calcium appeared to be associated with better performance in dissolution and pharmacokinetic studies, compared with raw atorvastatin calcium. In dissolution test, the release percentage of atorvastatin from SMEDDS mixture could rapidly reach more than 95% within 3 min. Oral $AUC_{0{\rightarrow}8hr}$ values in SD rats was $1994{\pm}335\;ng{\cdot}hr/mL$, which significantly increased (P<0.05) compared with raw atorvastatin calcium. The SMEDDS formulation was relatively stable when stored at $4^{\circ}C$ during 3 months. Our studies illustrated the potential use of SMEDDS for the delivery of hydrophobic compounds, such as atorvastatin, by the oral route.

• 대기
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• 제26권2호
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• pp.227-241
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• 2016

This study investigated the cause of the heavy snowfall that occurred in the East Coast of Korea from 6 February to 14 February 2014. The synoptic conditions were analyzed using blocking index, equivalent potential temperature, potential vorticity, maritime temperature difference, temperature advection, and ground convergence. During the case period, a large blocking pattern developed over the Western Pacific causing the flow to be stagnant, and there was a North-South oriented High-to-Low pressure system over the Korean Peninsula because of this arrangement. The case period was divided into three parts based on the synoptic forcing that was responsible for the heavy snowfall; detailed analyses were conducted for the first and last period. In the first period, a heavy snowfall occurred over the entire Korean Peninsula due to strong updrafts from baroclinic instability and a low pressure caused by potential vorticity located at the mid-troposphere. In the lower atmosphere, a North-South oriented High-to-Low pressure system over the Eastern Korea intensified the easterly airflow and created a convergence zone near the ground which strengthened the upslope effect of the Taebaek Mountain range with a cumulative fresh snowfall amount of 41 cm in the East Coast region. In the last period, the cold air nestled in the Maritime Province of Siberia and Manchuria strengthened much more than that in the first half and extended to the East Sea. The temperature difference between the 850 hPa air and the SST was large and convective clouds developed over the sea. The highest cumulative fresh snow amount of 39.7 cm was recorded in the coastal area during this period. During the entire period, vertically oriented equivalent potential temperature showed neutral stability layer that helped the cloud formation and development in the East Coast. The 2014 heavy snowfall case over the East Coast provinces of Korea were due to: 1) stagnation of the system by blocking pattern, 2) the dynamic effect of mid-level potential vorticity of 1.6 PVU, 3) the easterly air flow from North-South oriented High-to-Low pressure system, 4) the existence of vertically oriented neutral stable layer, and 5) the expansion of strong cold air into the East Sea which created a large temperature difference between the air and the ocean.