• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.228.2-228.2
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• 2015

We have developed a TOF-MEIS system using 70~100 keV He+. A TOF-MEIS system was designed and constructed to minimize the ion beam damage effect by utilizing a pulsed ion beam with a pulse width < 1 ns and a TOF delay-line-detector with an 120 mm diameter and a time resolution of 180 ps. The TOF-MEIS is an useful tool for interfacial analysis of the composition and structure of nano and bio systems. Our recent applications are reported. We investigated the effect with Polyaspartic Acid (pAsp) and Osteocalcin on the initial bone growth of calcium hydroxyl appatite on a carboxyl terminated surface. When pAsp is not added to the self-assembled monolayers of Ca 2mM with Phosphate 1.2 mM, the growth procedure of calcium hydroxyl appatite cannot be monitored due to its rapid growth. When pAsp is added to the SAMs, the initial grow stage of the Ca-P can be monitored so that the chemical composition and their nucleus size can be analyzed. Firstly discovered the existence of 1-nm-sized abnormal calcium-rich clusters (Ca/P ~ 3) comprised of three calcium ions and one phosphate ion. First-principles studies demonstrated that the clusters can be stabilized through the passivation of the non-collagenous-protein mimicking carboxyl-ligands, and it progressively changes their compositional ratio toward that of a bulk phase (Ca/P~1.67) with a concurrent increase in their size to ~2 nm. Moreover, we found that the stoichiometry of the clusters and their growth behavior can be directed by the surrounding proteins, such as osteocalcin.

• 한국정보과학회논문지:소프트웨어및응용
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• 제35권8호
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• pp.479-492
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• 2008

오늘날 소비자의 요구사항이 빠르고 다양한 형태로 변화함에 따라 기업의 자산인 비즈니스 프로세스도 이러한 변화에 민첩하게 대처할 수 있는 능력이 요구되고 있다. 이러한 요구를 만족시키기 위해서는 비즈니스 프로세스 모델의 생성 단계에서부터 발생할 수 있는 변화에 대하여 분석 및 표현이 가능한 핵심 자산이 존재해야 하며 이러한 핵심자산의 재사용을 통해 특성 변화를 만족하는 비즈니스 프로세스모델의 자동 생성이 가능해야 한다. 본 논문에서는 동일한 목적을 가지는 여러 비즈니스 프로세스 모델에 대하여 공통적인 특징을 공통성으로, 차별적인 특징을 가변성으로 분석하고 표현할 수 있는 비즈니스 프로세스 패밀리 모델을 설명한다. 그리고 비즈니스 프로세스 패밀리 모델의 공통성을 재사용하고 가변성에 대한 의사결정 정보를 반영하여 특정한 변화를 만족하는 비즈니스 프로세스 모델의 자동 생성을 지원하는 도구에 대하여 설명한다.

• 비파괴검사학회지
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• 제18권4호
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• pp.292-303
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• 1998

최근 자기적 특성의 변화가 재료의 미세조직적 상태에 민감하다는 보고가 있다. 재료의 미세조직은 상(phase), 결정립의 크기, 석출물 등의 타양한 인자로 구성되며, 본 연구에서는 이러한 인자들을 이용하여 재료의 특성과 Barkhausen noise(BN) 의 관계를 연관시키기 위 한 시도를 하였다. ASTM A 508 Gr. 3 원자로압력용기강을 대상으로 용접열영향부의 미세조직적인 변화를 일곱가지 대표적인 영역으로 구분하였고, 각 영역에서의 미세조직과 기계적특성의 변화를 파악한 후, 자 조건별로 BN을 측정하였다. 통상의 보자력이나 잔류자화 같은 자기적성질은 큰 변화가 없었지만, BN은 미세조직의 상태에 따라 현격한 변화를 보였다. 결정립과 석출물의 크기가 증가함에 따라 BN은 증가하였고. tempered martensite 보다는 tempered bainite 조직에서 높은 BN을 나타냈다.

• 약학회지
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• 제54권4호
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• pp.226-231
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• 2010

Oral fluid has become increasingly popular as an alternative specimen in the field of driving under the influence of drugs (DUID) and work place drug testing. In this study, an analytical method for the detection and quantification of ${\Delta}^9$-tetrahydrocannabinol (THC) and its metabolite, 11-nor-9-carboxy-${\Delta}^9$-tetrahydrocannabinol (THC-COOH) in oral fluid by SPE and GC-MS was established and fully validated. The stability of THC and THC-COOH in oral fluid during storage was also determined by examining the THC and THC-COOH concentration changes depending on time and container materials. Oral fluid samples were kept over 21 days at room temperature, $-4^{\circ}C$ and $-20^{\circ}C$ in two different specimen collection tubes; glass and polypropylene tubes. Three replicates for each condition with different temperature and types of a container were analyzed at five different time points over 21 days. When oral fluid samples were stored in glass tubes, the loss of both THC and THC-COOH was less than 10% at all room temperature, $-4^{\circ}C$ and $-20^{\circ}C$. However, in polypropylene tubes, the loss of both THC and THC-COOH increased significantly over the study period. In particular, the concentration of THC decreased more rapidly than that of THC-COOH at room temperature and the maximal percentage of THC lost was 90.3% after 21 days. The result indicates that it would be necessary to collect oral fluid samples in glass containers and cool the samples until analysis in order to prevent the degradation of analytes.

• 폴리머
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• 제30권3호
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• pp.210-216
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• 2006

담배 주류연 중 카보닐 화합물의 선택적 감소를 위한 필터 물질을 제조하기 위하여 하이드라존 반응에 있어서 촉진제로 사용되는 과염소산과 인산을 2,4-dinitrophenylhydrazine (2,4-DNPH)와 dansylhydrazine (DAH)과 함께 각각의 흡착제에 첨착시켰다. 제조된 첨착 흡착제의 구조는 FTIR/ATR을 이용하여 확인하였으며 SEM을 이용하여 표면을 관찰하였다. 또한 첨착 시간과 촉진제 그리고 첨착 시약에 따른 첨착량과 담배 주류연 중 카보닐 화합물의 흡착특성을 조사하였다. 첨착량은 첨착 시간에 따라 증가되었으며 2.4-DNPH를 첨착한 흡착제의 경우 다른 흡착제에 비해 카보닐 화합물의 제거 효율이 우수하였다. 또한 폴리아크릴계 흡착제에 2,4-DNPH를 첨착시킬 경우 다른 기재의 흡착제에 비해 우수한 제거 효율을 나타내었는데 이러한 결과들로부터 궐련필터로의 적용 가능성을 확인할 수 있었다.

• 한국재료학회지
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• 제14권10호
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• pp.701-706
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• 2004

Bismuth layered structure ferroelectric thin films, La-substituted $Bi_{4}Ti_{3}O_{12}$ ($Bi_{1-x}La_{x}Ti_{3}O_{12}$, x=0.75, BLT) were prepared on the $Pt(111)/Ti/SiO_2/Si(100)$ substrates by a sol-gel spin coating process. The thin films were annealed in various conditions, i.e., oxygen, nitrogen and vacuum atmospheres for various annealing time. We investigated the annealing condition effects on the grain orientation and ferroelectric properties. The measured XRD patterns revealed that the BLT thin films showed only $Bi_{4}Ti_{3}O_{12}$-type phase with random orientation. $La^{3+}$ ion substitution for $Bi^{3+}$ ion in perovskite layers of $Bi_{4}Ti_{3}O_{12}$ decreased the degree of c-axis orientation and increased the remanent polarization ($2P_{r}$). The remanent polarization ($2P_{r}$) and the coercive field ($2E_{c}$) of the BLT thin film annealed at $650^{\circ}C$ for 5 min in oxygen atmosphere were $87{\mu}C/cm^2$ and 182 kV/cm, respectively, at an applied electric field of 240 kV/cm. For all of the BLT thin films annealed in various conditions, the fatigue resistance was shown. The improvement of ferroelectric properties with La substitution in $Bi_{4}Ti_{3}O_{12}$ could be attributed to the changes in space charge densities and grain orientation in the thin film.

• 대한한방내과학회지
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• 제19권2호
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• pp.7-16
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• 1998

Background and Purpose The increasing evidence for neurally mediated cardiac damage and sudden death has focused attention on the central autonomic control of cardiac function. Power spectral analysis of heart rate variability(HRV) can detect autonomic consequences of stroke. We performed power spectral analysis of heart rate variability from 24-hour holter recording to identify cerebral hemispheric lateralization and gender effect in cardiac autonomic control. Methods Data were obtained from 24-hour holter recordings in 30 consecutive patients with hemispheric brain infarction in the subacute phase. We analysed the time domain and frequency domain measures of HRV and ST segment by hemispheric lateralization and Gender. Results ST segment was depressed in women compared with man. There was no statistically significant differences between right and left hemisphere stroke patients in any standard index of HRV and ST segment changes. Conclusions These data are partial consistent with evidence from the recent literature that two cerebral hemispheres and gender have a differential influence on the nature and severity of cardiac dysfunction. We think the prospective and definite study was necessary.

• Spatial Information Research
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• 제20권1호
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• pp.19-26
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• 2012

기후변화의 원인 중 탄소배출이 가장 큰 비중을 차지하고 있어 탄소배출 감소의 필요성이 전 세계적으로 제기되고 탄소배출을 감소하기 위한 국제적 움직임이 가속화되고 있다. 선진국들은 녹색산업을 신성장동력 산업으로 활용하는 전략을 추진 중이며 탄소저감형도시(low carbon city)에 대한 관심이 높아지고 있다. 현재 우리나라에서 진행되고 있는 U-City 사업에 대하여 U-City 도입 이전 도시와 U-City 도입 도시의 탄소배출량 변화를 분석하여 이산화탄소 저감효과에 대한 분석이 필요하다. 본 연구에서는 U-City 도입 이전과 도입 이후의 이산화탄소 발생량을 비교, 분석하여 U-City 도입에 따른 탄소저감 효과를 정량화하고자 하였다. U-City 도입이전의 도시는 1기 신도시 중에 성남시 분당구와 고양시 일산구를 대상으로 하였으며, U-City 도입이후의 도시로는 화성동탄 U-City를 선정하여 비교한 결과 탄소배출량이 30%정도 줄어든 것으로 결과가 도출되었다.

• Biomolecules & Therapeutics
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• 제22권5호
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• pp.445-452
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• 2014

The purpose of this study was to investigate the therapeutic effects of DA-9801, an optimized extract of Dioscorea species, on diabetic peripheral neuropathy in a type 2 diabetic animal model. In this study, db/db mice were treated with DA-9801 (30 and 100 mg/kg, daily, p.o.) for 12 weeks. DA-9801 reduced the blood glucose levels and increased the withdrawal latencies in hot plate tests. Moreover, it prevented nerve damage based on increased nerve conduction velocity and ultrastructural changes. Decrease of nerve growth factor (NGF) may have a detrimental effect on diabetic neuropathy. We previously reported NGF regulatory properties of the Dioscorea genus. In this study, DA-9801 induced NGF production in rat primary astrocytes. In addition, it increased NGF levels in the sciatic nerve and the plasma of type 2 diabetic animals. DA-9801 also increased neurite outgrowth and mRNA expression of Tieg1/Klf10, an NGF target gene, in PC12 cells. These results demonstrated the attenuation of diabetic peripheral neuropathy by oral treatment with DA-9801 via NGF regulation. DA-9801 is currently being evaluated in a phase II clinical study.

• 한국식품조리과학회지
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• 제27권4호
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• pp.67-73
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• 2011

This study was performed to assess the neuroprotective effects of methanolic extracts from sweet persimmon peel (PPE) against glutamate-induced cytotoxicity in hybridoma N18-RE-105 cells. The neuroprotective effects of PPE in N18-RE-105 cells were measured using the MTT reduction assay, LDH release assay, and phase-contrast microscopy. The results of the MTT reduction assay showed that treating cells with 500 ${\mu}g/ml$ PPE resulted in cell viability of 66.9%. Additionally, the morphological changes and the results of the LDH release assay showed that glutamate-induced damage to nerve cells was strongly inhibited by PPE. GSH content of N18-RE-105 cells was 3.5 ${\mu}M$ compared to that of the control, whereas pretreatment with 500 ${\mu}g/ml$ PPE increased GSH content by 4.7 ${\mu}M$. PPE was fractionated with hexane, and that layer had the highest neuroprotective effects in glutamate-stressed N18-RE-105 cells. In conclusion, our data showed that glutamate potentiated the effects of N18-RE-105 cell death by a mechanism involving oxidative stress. Therefore, PPE may be a potential candidate for prevention and therapy of neurodegenerative diseases.