• International Journal of Automotive Technology
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• 제7권2호
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• pp.209-216
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• 2006

A study has been conducted for an optimal processing and an apparatus for manufacturing a laser welded tube for one-body formed bumper beam. The tube dimensions used in calculation were the thickness of 1.4 mm, the diameter of 105.4 mm and the length of 2000 mm. The tube was formed of a cold rolled high strength steel plate(tensile strength of 600 MPa). The two-roll bending method was the optimal tube forming process in comparison with the UO-bending method, the bending method on the press brake, the multi-step continuous roll-forming method and the 3-roll bending method. Monitoring of the welding quality was conducted and the seam tracking along the butt-joint lengthwise to the tube axis was also examined. The longitudinal butt-joint was welded by using a $CO_2$ laser welding machine equipped with a seam tracker and a plasma sensor. The $CO_2$ laser tube welding machine could be used for precise seam tracking and real-time monitoring of the welding quality. As a result, the developed laser welded tube could be used for a one-body formed automobile bumper beam.

• 한국통신학회논문지
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• 제8권4호
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• pp.164-171
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• 1983

본 논문에서는 비교적 짧은 계단형 멀티모우드 광섬유를 이용하여 여러 정보의 채널을 전송하는 광멀티플렉싱 기술인 각도분할방식(ADM: Angular Division Multiplexing)에 대해 논하였다. 평면파 입력에 대한 광섬유 내의 모우드 결합과 출력 파워 분포가 계산되었으며 시스템의 혼신도 결정이 제시되었다. 모우드 결합 하에서 광섬유의 길이와 입력조건에 따른 펄스폭이 평면 도파판과 광섬유에 대해 비교, 계산되었다. NA(Numerical Aperture)아래의 입력각에 대한 각도폭은 입력각이 클수록 줄어들었으며 출력은 입력각에 파워가 집중된 환형으로 나타났으며 이는 ADM시스템의 중요한 요인이 되었다.

• Journal of Magnetics
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• 제19권2호
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• pp.181-184
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• 2014

The aim of the present study was to examine whether motor imagery (MI) practice in conjunction with repetitive transcranial magnetic stimulation (rTMS) applied to stroke patients could improve theirgait ability. This study was conducted with 29 subjects diagnosed with hemiparesis due to stroke.The experimental group consisted of 15 members who were performed MI practice in conjunction with repetitive transcranial magnetic stimulation, while the control group consisted of 14 members who were performed MI practice and sham therapy. Both groups received traditional physical therapy for 30 minutes a day, 5 days a week, for 6 weeks; additionally, they received mental practice for 15 minutes. The experimental group was instructed to perform rTMS and the control group was instructed to apply sham stimulation for 15 minutes. Gait analysis was performed using a three-dimensional motion capture system, which is a real-time tracking device that delivers data via infrared reflective markers using six cameras. Results showed that the velocity, step length, and cadence of both groups were significantly improved after the practice (p<0.05). Significant differences were found between the groups in velocity and cadence (p<0.05) as well as with respect to the change rate (p<0.05) after practice. The results showed that MI practice in conjunction with rTMS is more effective in improving gait ability than MI practice alone.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2207-2212
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• 2008

The next generation of Korean high-speed train under development will be designed for the maximum operating speed of 350km/h and maximum speed of 400km/h. This high-speed operation may cause the noise and vibration problems around tunnel exit due to the higher micro-pressure wave than present level. In this study, the nose shape optimization was conducted for the countermeasure against these problems. Axi-symmetric solver was used for numerical simulation, and response surface was used for efficiency of optimization process. Also the multi-step optimization was conducted to find out more accurate optimal shape. Through these analysis and optimization, it was found out that the optimal nose shapes for minimization of micro-pressure wave are definitely different along the nose length variation. And the mechanism of micro-pressure wave reduction was closely investigated by the analysis of generation process of compression wave in tunnel. The results are expected to be used as design guideline for performance improvement of the next generatin of Korean high-speed train.

• 한국철도학회논문집
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• 제5권3호
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• pp.148-157
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• 2002

A health monitoring system becomes a useful tool to obtain information on long term behavior of the important railway structures such as very long span and special type bridges. The health monitoring system not only gives the direct measurement data of the railway bridges but also provides the basic data on the maintenance of the structures. Therefore, periodic calibrations of the health monitoring system will be a necessary step toward precise and accurate assessment of the railway bridges. In this study, the calibration and gauge factor readjustment process made for the health monitoring system installed in the railroad bridges is reviewed and some findings are explained in detail: specifically, the calibrators made for this purpose are illustrated and the regression processes of the calibration on long-term displacement using water level sensor, longitudinal displacement using LVDT sensor, instantaneous displacement using LVDT sensors and accelerometer are described in full length. Based on the regression results, it was found that the gauge factors need to be readjusted according to the regression equation but, since the deviation or shift is not serious so far, long-term observation on each sensor is also recommended. Future work will be concentrated on the long-term analysis of each sensor and on the database creation so that the assessment of the structures is possible.

• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.574-580
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• 2007

Full-length chloride intracellular channel protein 1 (CLIC1) is a member of the family of proteins related to bovine chloride intracellular channel p64. Mutations in the SEDL gene cause spondyloepiphyseal dysplasia tarda (SEDT), a rare X-linked chondrodysplasia. The link between the intracellular chloride channels and SEDL is an important step toward understanding their functional interplay. In the present study, CLIC1 protein was subcloned into the pGEX-KG vector and overexpressed in XL-1 blue cells. We developed a large-scale expression system composed of glutathione S-transferase (GST) fused with a 240-amino-acid CLIC1 protein in Escherichia coli. The soluble CLIC1 protein was successfully purified to homogeneity, and its purity, identity, activity and conformation were determined using SDS-PAGE, MALDI-MS, biophotometer and circular dichroism spectroscopic studies. The binding of both CLIC1 and SEDL proteins in vitro was detected by BIAcore biosensor and fluorescence measurements.

• 전산구조공학
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• 제8권3호
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• pp.59-66
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• 1995

점소성이론을 이용하여 충격하중을 받는 구조물의 거동을 하중시간에 따라 조사하였다. 점소성이론은 재료의 소성특성과 시간변화특성을 나타내는 Rheology 이론을 동시에 고려한 이론이다. 점소성 구성방정식을 구한 후, 이를 이차원 유한요소해석프로그램에서 심어서 평면응력, 평면 변형률, 축대칭 구조물의 동적 거동을 해석할 수 있도록 기존프로그램을 수정.개발하였다. Perzyna에 의한 점소성 구성방정식은 유한요소해석에서 Explicit 적분법을 사용해야 하는데 반하여, 본 연구에서 구한 구성방정식은 Implicit 적분법을 적용할 수 있도록 Algorithm을 개발하였다. 다양한 하중시간을 갖는 충격하중을 선택한 구조물에 가해 해석한 결과, 하중시간이 길수록 변형이 증가하여 점소성 거동을 하며, 높은 고유진동수 성분이 점소성거동으로 거의 소멸된다는 결론을 얻었다.

• Animal cells and systems
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• 제10권4호
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• pp.197-201
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• 2006

Diaminopimelate decarboxylase (DAPDC, EC 4.1.1.20) catalyzes the conversion of diaminopimelate into lysine (Lys), which is the last step in Lys biosynthetic pathway. The genes for DAPDC have been reported in many bacteria, and more recently in Arabidopsis. Here we report characterization of a gene for DAPDC from rice (OsDAPDC). Sequence analysis of a cDNA clone revealed a full-length open reading frame for OsDAPDC that encoded 490 amino acids, approximately 53.2 kDa protein. The OsDAPDC protein contains a consensus binding site for pyridoxal-5'-phosphate as a cofactor and has a sequence at the amino terminus that resembles a transit peptide for localization to plastids, similar to that of Arabidopsis. Single gene encoding DAPDC was found in chromosome II in rice. The predicted amino acid sequence of OsDAPDC is highly homologous to that of the enzymes for DAPDC encoded by lysA of many bacteria. Expression of OsDAPDC in lysA mutants of Escherichia coli shows that the gene is able to functionally complement the mutants. These results suggest that OsDAPDC encodes a protein for diaminopimelate decarboxylase in rice.

• 대한기계학회논문집
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• 제12권1호
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• pp.123-130
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• 1988

본 연구에서는 비교적 데이터 처리속도가 빠른 80286계의 CPU를 사용한 16bit 퍼스널 컴퓨터를 이용하는 경우보다, 가격면에서는 훨씬 유리하면서도, 성능은 거의 뒤지지 않는 피로시험 자동화 및 피로거동 고정밀 측정을 위한 시스템을 완성하였다. 본 연구에서 사용한 방법 및 작성한 소프트웨어등은 사용시험기, 피로연구 대상등에 거의 관계없이 이용이 가능하나, 여기서는 편의상, 시험기로서는 폐루우프(closed-loop)유압서어보 피로시험기를 사용하였으며, 피로거동의 측정에 대해서는 주로 피로균열지전을 대상으로 하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.587-587
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• 2013

ZnS is well-known direct band gap II-VI semiconductor, and it attracts intense interest due to its excellent properties of luminescence which enable ZnS to have promising materials for optical, photonic and electronic devices. Especially, the emission wavelength of ZnS falls in the UV absorption band of most organic compoundsand biomolecules, thus it is envisaged that ZnS based devices may find applications in increasingly important fluorescence sensing. We have developed a facile and effective one-step process for the fabrication of single-crystalline and pure-wurtzite ZnS nanostructures possessing sharp band-edge emission at room-temperature having diverse length-to-width ratios. Each of nanostructures was composed of chemically pure, structurally uniform, single-crystalline, and defect-free ZnS. These features not only suppress trap or surface states emission centered at 420 nm, but also enhance UV band-edge emission centered at 327 nm, which give as-synthesized our ZnS nanostructures possible sharp UV emission at room temperature. The reaction medium consisting of mixed solvents such as hydrazine, ethylenediamine, and water as well as proper reaction time and temperature have played an important role in the crystallinity and optical properties of ZnS nanostructures. As-synthesized our ZnS nanostructures possessing sharp UV emission guarantee high potential for both fundamental research and technological applications.