• 한국자동차공학회논문집
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• 제11권6호
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• pp.127-133
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• 2003

NSD(No Spin Differential) has been developed fer a military truck. A benchmarking study for USA and Russian NSD has been carried out. Axiomatic approach has been applied for improving the design. A test code for NSB has been developed and applied to the developed sample. In the test results of comparing the developed sample with the USA imported sample, three major characteristics-the noise, mobility and steerability - are in the range of the intended target. A practical process for the evolution design is proposed.

• 한국자동차공학회논문집
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• 제13권4호
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• pp.32-38
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• 2005

Two No Spin Differential(NSD) models were benchmarked for a project of Dual-Use Technology The Axiomatic approach was utilized to evaluate two models and to derive an evolutionary design from the evaluated results. Test methodology is developed and used to evaluate the mobility, steerability, durability and noise of the newly developed sample. The test results of NSD sample on the test methodology are very positive regarding functional performances.

• International Journal of Automotive Technology
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• 제7권5호
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• pp.595-601
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• 2006

Two No Spin Differential(NSD) models were benchmarked for a project of Dual-Use Technology. The Axiomatic approach is utilized to evaluate the designs of the models. The Independence Axiom is satisfied at the top level of design but not at the second level, which implies the design exhibits coupling and will admit design improvements. The detailed process of design evaluation is described. It is shown that it is possible to develop a unique and evolutionary NSD design by solving the problems that cause coupling within two models.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2000년도 춘계학술대회
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• pp.5.1-5
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• 2000

• International Journal of Automotive Technology
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• 제7권7호
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• pp.795-801
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• 2006

A No Spin Differential (NSD) design has been improved from evaluation of two NSD models utilizing the axiomatic approach. New design parameters of the second level are developed to satisfy the independence axiom. The design matrices are determined to decouple the relationship between design parameters and process parameters. The values of process parameters are then determined to optimize and improve the NSD design. Consequently a unique and evolutionary NSD design is achieved with the aid of the axiomatic approach.

• Preventive Nutrition and Food Science
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• 제3권2호
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• pp.203-209
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• 1998

The development of methods for the identification of irradiated foods helps enforce national and international regulations on labelling to ensure the consumer's free choice to buy irradiated or unirradiated foods. and the availabilityof such methods may assist the promotion of international trade in irradiated food products and help prevent abuse of the technology. A number of approaches to determine the physical , chemical, microbiological and biological changes that occur in foods treated with ionizing radiation have been studied. However no single method is universally applicable. Among physical measurements, the leading methods of indentification are electron spin resonance (ESR) spectroscopy and thermoluminescence(TL). ESR is an established non-destructive method for the analysis of free radicals from their traps and TL is the emission of light from irradiated mineral extracts by heating. Viscosity of carbohydrate polymers by causing chain breaks by irradiation, measuring the impedance of potatoes and detection of gases produced radiolytically are promising techniques for identification purposes. Irradiated water-containing foods show significant supercooling when monitored with a differential scanning calorimeter (DSC), which can be applied to identifying irradiated ones.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.213-213
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• 2012

It has been known that quantum confinement effect of CdSe nanocrystal was observed by increasing the number of deposition cycle using successive ionic layer adsorption and reaction (SILAR) method. Here, we report on thermally-induced quantum confinement effect of CdSe at the given cycle number using spin-coating technology. A cation precursor solution containing $0.3\;M\;Cd(NO_3)_2{\cdot}4H_2O$ is spun onto a $TiO_2$ nanoparticulate film, which is followed by spinning an anion precursor solution containing $0.3\;M\;Na_2\;SeSO_3$ to complete one cycle. The cycle is repeated up to 10 cycles, where the spin-coated $TiO_2$ film at each cycle is heated at temperature ranging from $100^{\circ}C$ to $250^{\circ}C$. The CdSe-sensitized $TiO_2$ nanostructured film is contacted with polysulfide redox electrolyte to construct photoelectrochemical solar cell. Photovoltaic performance is significantly dependent on the heat-treatment temperature. Incident photon-to-current conversion efficiency (IPCE) increases with increasing temperature, where the onset of the absorption increases from 600 nm for the $100^{\circ}C$- to 700 nm for the $150^{\circ}C$- and to 800 nm for the $200^{\circ}C$- and the $250^{\circ}C$-heat treatment. This is an indicative of quantum size effect. According to Tauc plot, the band gap energy decreases from 2.09 eV to 1.93 eV and to 1.76 eV as the temperature increases from $100^{\circ}C$ to $150^{\circ}C$ and to $200^{\circ}C$ (also $250^{\circ}C$), respectively. In addition, the size of CdSe increases gradually from 4.4 nm to 12.8 nm as the temperature increases from $100^{\circ}C$ to $250^{\circ}C$. From the differential thermogravimetric analysis, the increased size in CdSe by increasing the temperature at the same deposition condition is found to be attributed to the increase in energy for crystallization with $dH=240cal/^{\circ}C$. Due to the thermally induced quantum confinement effect, the conversion efficiency is substantially improved from 0.48% to 1.8% with increasing the heat-treatment temperature from $100^{\circ}C$ to $200^{\circ}C$.

• Journal of Korean Neurosurgical Society
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• 제29권7호
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• pp.891-898
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• 2000

Objective : It is difficult to differentiate intramedullary spinal cord tumors preoperatively from non-neoplastic pathologies in patients presenting as non-compressive myelopathies in magnetic resonance imaging(MRI). In this report, the authors reviewed nonneoplastic intramedullary spinal cord lesions preoperatively diagnosed as tumors and discussed their clinical and radiological characteristics and usefulness of surgical intervention. Methods : From January, 1985 to January, 1999, authors experienced eight non-neoplastic pathologies mimicking intramedullary spinal cord tumors and analysed their medical records, radiological findings and histopathological specimens retrospectively. Results : There were five males and three females and the duration of symptoms were from two to 20 months(mean, 9.8 months). The location of lesions were four cervical, one cervicothoracic and three thoracic. All patients manifested sensory abnormality, seven motor weakness, and six bladder symptom. All cases had swollen spinal cords and increased signal intensities in spin-echo sequences. Six cases showed contrast enhancement : four cases were focal and two diffuse. Under the impression of intramedullary tumors, the patients were operated upon. Final diagnoses on the base of clinical and pathologic finding were : three subacute necrotizing myelopathies, two multiple scleroses, two myelopathy of unknown etiology. One case showed no gross abnormality in surgical field in spite of adequate exposure of the lesion, so biopsy was not performed. In that case, postoperative MRI revealed spontaneous resolution of the lesion. Conclusion : MRI is invaluable diagnostic tool in screening myelopathies. However, its high sensitivity and lack of specificity make difficulty in preoperative differential diagnosis of non-compressive myelopathies. Although no surgical morbidity occurred in our series, we sometimes failed to confirm definite diagnosis even with biopsy. In such a circumstance, long-term follow up is needed.

• Investigative Magnetic Resonance Imaging
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• 제4권2호
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• pp.107-112
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• 2000

목적 : 양각 자궁과 중격 자궁의 자기공명영상 감별에 있어서 자궁 격막의 신호 강도 비교가 유용한지 알아보는 데에 있다. 대상 및 방법 : 수술로 확진된 양각 자궁 5예와 중격 자궁 6예를 대상으로, 수술전의 자기공명영상 소견을 후향적으로 재분석하였다. 양각의 거리, 자궁 저부의 외형 양각이 이루는 각도 등으로 양자의 감별은 수술 전에 이미 전례에서 가능하였기 때문에, 상기의 자기공명영상 소견은 연구 대상에서 제외하였다. 양각 자궁과 중격 자궁에서 자궁 내에 존재하는 격막의 신호 강도를 1.5-T기기를 이용한 T1 강조 및 급속 스핀 에코 T2 강조 축상 및 관상면 영상에서 비교하였다. 특히 급속 스핀 에코 T2 강조 영상에서 격막의 신호 강도를 자궁근이나 접합대의 신호 강도와 비교하여 분석하였다. 결과 : 양각 자궁(n=5)과 중격 자궁(n=6)의 자궁 격막은 전례 모두 T1 강조 영상에서 자궁근과 비슷한 신호 강도를 보였다. T2 강조 영상에서는 양각 자궁(n=5)의 경우 자궁근층과 비슷한 신호 강도를 보인 경우가 3예, 자궁근층보다 낮은 신호 강도를 보인 경우가 2예이었다. 중격 자궁(n=6)은 T2 강조 영상에서 자궁근층과 비슷한 신호 강도를 보인 경우가 2예, 자궁근층보다 낮은 신호 강도를 보인 경우가 2예, 접합대와 비슷하거나 그보다 낮은 신호 강도를 보인 경우가 2예이었다. T2 강조 영상에서 자궁 격막의 상부/하부 신호 강도가 상이하게 관찰된 경우는 양자 모두에서 1예도 없었다. 결론 : 양각 자궁과 중격 자궁의 자기공명영상에서 자궁 격막의 신호 강도는 다양한 양상을 보이므로 양자의 감별에 단독적으로 사용되어서는 곤란하다. 임상적으로 중요한 양자의 감별에는 자궁 격막의 신호 강도뿐만 아니라, 자궁 저부의 외형, 양각의 거리, 양각이 이루는 각도 등 종합적인 자기공명영상 소견을 고려해야 한다.

• 폴리머
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• 제25권6호
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• pp.803-810
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• 2001

새로운 개념의 초분지형 비선형 광학 고분자 (PE-Azo/Hyper)를 AB$_2$형의 기능기를 가지는 단량체 4-[N,N-bis(hydroxyethyl)amino-4'-formyl]azobenzene (CHO-DOH)으로부터 Knoevenagel 축중합 반응을 통하여 합성하였다. 겔크로마토그래피상에서 폴리스티렌을 기준시료로 측정된 중합체의 무게평균분자량은 M$_{w}$ =61,800 (M$_{W}$ /M$_{n}$=1.86)이었고 중합체의 용해도를 조사한 결과 1-methyl-2-pyrrolidinone, N,N-dimethylformamide 등의 반양자성극성 유기용매에 잘 녹았으며 따라서 이들 용매를 이용하여 양질의 박막성형이 가능하였다. 또한 열시차 분석법으로 중합체 PE-Azo/Hvper의 열적 성질을 조사한 결과 녹는점이 관찰되지 않아 무정형으로 판명되었으며 유리 전이 온도는 $121^{\circ}C$로 나타났다. 폴링에 의하여 극성 배향된 중합체 박막의 2차 비선형 계수를 Nd : YAG 레이저 (1064 nm)를 이용하여 Maker fringe 방법으로 측정한 결과 $d_{33}$= 25.4 pm/V로 비교적 높은 값을 나타내어 초분지형 고분자에서도 극성배향이 이루어져 비선형성이 발현됨을 관찰할 수 있었다.