• 한국물환경학회지
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• 제25권5호
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• pp.720-726
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• 2009

We investigated the most effective pre-treatment processes and LC/MS/MS condition for microcystins analysis. With a step-by-step pre-treatment, efficiencies of several established methods were compared. At the level of cell burst, sonication method was found to be the most efficient. As a mycrocystins first extraction solvent, 5% acetic acid showed the highest efficiency. An isolation and recovery rate of mycrocystins of ODS Sep-Pak $C_{18}$ cartridge was higher than HLB SPE cartridge. As a final elution solvent from cartridge, 100% MeOH had a better efficiency than others. Using a LC/MS/MS, effective analytical methods were established. C18 reverse column was used and gradient elution was performed with using acetonitrile, 0.1% formic acid as a mobile phase. We analysed to 0.8 mL/min flow rate fit to the $5{\mu}m$ particle size column and $55^{\circ}C$ housing temperature. The validity of established analytical method was evaluated that MDL as average $0.050{\pm}0.014{\mu}g/L$ and LOQ as average $0.160{\pm}0.045{\mu}g/L$ had a good sensitivity over 40 magnification rather than $2{\mu}g/L$ detection limit of HPLC.

• Journal of Acupuncture Research
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• 제22권6호
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• pp.135-140
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• 2005

Objectives : There have been several studies about the quality of acupuncture needle tip recently. We have investigated the condition of the tip of the acupuncture needles in the last studies. In the former studies, we discovered the metallic scuff, lumps and irregularities of the acupuncture needle tips under the microscope. But, no information was available on those foreign materials' identity. Methods : We have selected 200 needles of 1000 pieces from several companies by randomized methods. And we observed the tip of the 6 needles selected finally at ${\times}1000\;or\;{\times}3000$ magnification and analyzed the components of the metallic scuff, lumps and irregularities of the needle tips with a SEM-EDX analyser. Results : We found that the identity of the metallic scuff, lumps and irregularities of the needle tips were metallic materials and silicon. For example, A point was composed of Fe(69.78%), Cr(17.71%), Ni(8.11%), Zn(2.04%), Si(1.23%), Mn(1.12%), and B point was composed of Si(66.40%), Fe(26.76%), Cr(6.84%). Conclusion : The results of this study confirm that there is a real possibility of the remaining of metallic materials and silicon in body of patient, after acupuncture treatment. Therefore, it is necessary to intensify our efforts to make needles of good quality and to concentrate on manufacturing process of acupuncture needles completely to be free from danger in acupuncture treatment.

• 대한치과보철학회지
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• 제32권2호
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• pp.225-233
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• 1994

The restorations of the severely damaged teeth by post core have been increased with the developement of endodontic procedures. But high failure rates of these procedures being reported, various restorative modifications were induced for successful treatments. Cast post-core and prefabricated post with core buildups are choice of treatment. The main causes of failure of the restorations are the fracture of post and core, root fracture, and recurrent caries due to microleakage. Recently, the acid etching technique and the use of dentin bonding agent at tooth surface to reduce the possible microleakage at the tooth-restoration interfaces were introduced. The object of this study was to measure and compare the microleakage by the types and cementation methods of post-core. For this study, forty extracted human anterior teeth were selected for specimen. After cleansing and routine endodontic procedures, anatomic crowns of each specimen were removed at the level of 2mm above the cementoenamel junction. Canals were preparated for post insertion and specimens were divided into four groups randomly. Post-cores were fabricated according to method for each group. Microleakage was measured by length of dye penetration at the tooth-restoration interfaces with measuring microscope at 50 magnification. Oneway ANOVA and t-test were performed for statistical analysis of resulting data. The following results were obtained from this study. 1. There wert significant statistical differences in degree of microleakage between each group (p<0.01). 2. Cast post-core cemented with ZPC (Group I) showed the most severe microleakage pattern$(1.5547{\pm}0.0872mm)$, and cast post-core cemented with adhesive resin cement after tooth surface treatment with dentin bonding agent (Group II) showed the least microleakage $(0.1497{\pm}0.0872mm)$. 3. Group IV revealed less dye penetrations than group III, but no statistical significance was seen between two groups.

• Asian Pacific Journal of Cancer Prevention
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• 제14권1호
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• pp.583-587
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• 2013

This study aimed to investigate tumor microvessel density (MVD) and lymphatic vessel density (LVD) using the Chalkley method as predictive markers for the risk of axillary lymph node metastasis and their relationship to other clinicopathological parameters in primary breast cancer cases. Forty two node-positive and eighty node-negative breast cancers were immunostained for CD34 and D2-40. MVD and LVD were counted by the Chalkley method at x400 magnification. There was a positive significant correlation of the MVD with the tumor size, coexisting ductal carcinoma in situ (DCIS) and lymph node metastases (P<0.05). In multivariate analysis, the MVD (2.86-4: OR 5.87 95%CI 1.05-32; >4: OR 20.03 95%CI 3.47-115.55), lymphovascular invasion (OR 3.46, 95% CI 1.13-10.58), and associated DCIS (OR 3.1, 95%CI 1.04-9.23) independently predicted axillary lymph node metastasis. There was no significant relationship between LVD and axillary lymph node metastasis. However, D2-40 was a good lymphatic vessel marker to enhance the detection of lymphatic invasion compared to H and E staining. In conclusion, MVD by the Chalkley method, lymphovascular invasion and associated DCIS can be additional predictive factors for axillary lymph node metastases in breast cancer. No relationship was identified between LVD and clinicopathological variables, including axillary lymph node metastasis.

• Journal of Magnetics
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• 제3권2호
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• pp.44-48
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• 1998

Scanning Electron Microscopy with Polarization Analysis (SEMPA) was used to image the surface magnetic domain structure of the 100 ${\mu}{\textrm}{m}$ thick 3% Si-Fe sheet. The thin-gauged 3% Si-Fe strips with magnetic induction ($B_{10}$) from 1.98 to 1.57 Tesla were prepared via conventional metallurgical processes including melting, hot-and cold-rolling, intermediate annealing and final annealing. Using SEMPA, it was observed that the $B_{10}$ (1.98 T) Tesla sample was almost composed of 180$^{\circ}$ stripe domains which are parallel to rolling direction. On the other hand the 3% Si-Fe sheet with $B_{10}$ (1.57 T) Tesla was composed of large 180$^{\circ}$stripe domains that are slanted about 30$^{\circ}$to the rolling direction and complex magnetic domain structures like tree and zigzag pattern. The 180$^{\circ}$stripe domains, which covered a major part of the sample, had (110)<001> Goss texture parallel to the rolling direction. The domain walls between 180$^{\circ}$stripe domains were the conventional Bloch type walls. On the other hand, the 90$^{\circ}$domains, which covered minor part on edge of the sample, were observed in (200) grains. The domain walls between 90$^{\circ}$domains were the Neel type walls. In high magnification, the elliptical singularity at the Neel walls was clearly observed.

• 한국지진공학회논문집
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• 제2권2호
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• pp.35-44
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• 1998

최근의 중.소규모의 연이은 지진활동은 한반도도 지진에 대하여 안전지대는 아닌 것으로 생각되고 있으며, 1995년 일본의 Kobe 지진 대 참사는 국내에도 지진에 관한 많은 관심을 고조시키고 있다. 그러나, 국내의 구조물의 내진설계를 위한 사용되는 지진파에 대한 연구는 매우 미흡하며, 최근까지도 국내에서는 외국의 설계용 지진파를 그대로 사용하거나 설계응답스펙트럼을 이용하고 있는 실정이다. 본 논문에서는 국내지진파의 물리적 특성, 즉, 주기-빈도 분포, 확률밀도분포, Fourier Spectrum 및 응답스펙트럼을 구하여 비교.분석하였다. 또한 이상화된 인공지진파를 산출하여 이를 현재 교통량의 폭발적인 증가와 도로의 선형성을 이유로 사각을 가진 교량구조물이 많이 건설되고 있는바, 70$^{\circ}$사각슬래브교에 대한 지진해석을 수행하여 인공지진의 합리적 해석 횟수를 규명하였다.

• 한국정보통신학회논문지
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• 제16권10호
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• pp.2280-2286
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• 2012

본 논문에서는 고속 컴퓨터 집적 영상 복원 방법을 이용하여 새로운 형태의 3D 비선형 상관기를 제안한다. 고속 컴퓨터 집적 영상 복원 방법을 구현하기 위해서 기존의 방법에서 확대 과정을 제거함으로서 고속 계산이 가능하다. 제안하는 상관기는 먼저 기준 물체와 목표 물체의 요소 영상들을 렌즈 배열을 통해 픽업한다. 이 픽업된 영상에 고속 컴퓨터 집적 영상 복원 방법을 사용하여 목표 평면 영상과 기준 평면 영상들이 복원된다. 복원된 기준 평면 영상과 목표 평면 영상들 간의 비선형 상호상관을 통해 인식을 수행한다. 비선형 상관 연산의 사용은 상관기의 3D 물체 인식 성능 향상시킬 수 있다. 제안된 방법의 유용함을 보이기 위해 기존의 방법과 비교하여 기초적인 상관관계 실험을 수행하고 그 결과를 보고한다.

• 융합보안논문지
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• 제6권4호
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• pp.141-151
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• 2006

지난 2003년 1월 25일 인터넷 마비사고와 2004년 주요 국가기관 해킹사건을 겪으면서 사이버 위협의 파괴력이 국가안보에 직접적이고 심각하게 위협하는 단계에까지 도달하였다. 그래서 사이버테러나 사이버전(cyber warfare)은 더 이상 가상적 상황이 아닌 현실적이며, 실체적인 안보상황으로 상대국의 군사지휘체계는 물론 통신, 에너지, 금융, 수송체계 등 국가 주요기능 무력화의 전쟁 개념의 확대로 재인식되고 있다. 이러한 시점에서 정보전, 정보작전, 네트워크 중심전등 혼재된 유사 용어들 속에서 사이버전에 대한 명확한 개념 정립 필요하고 각 국의 사이버전 동향 분석 및 국내 사이버전 현황 분석을 통해 문제점을 식별, 보완책 마련이 필요하다. 그래서 본 논문에서는 국가적 위기를 효율적으로 관리하고, 효과적이며 능동적으로 사이버전을 수행할 수 있는 발전방향과 상대적으로 사이버전 관련 기술 및 전문 인력 운영적측면에서 열세에 놓여 있는 군의 사이버전 수행체계에 대한 혁신방향을 연구를 하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제18권4호
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• pp.15-20
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• 2016

The effects of electron beam (EB) irradiation on the superconducting critical temperature ($T_c$) and critical current density ($J_c$) of YBCO films were studied. The YBCO thin films were irradiated using a KAERI EB accelerator with an energy of 0.2 MeV and a dose of $10^{15}-10^{16}e/cm^2$. A small $T_c$ decrease and a broad superconducting transition were observed as the EB dose increased. The value of $J_cs$ (at 20 K, 50 K and 70 K) increased at doses of $7.5{\times}10^{15}$ and $2.2{\times}10^{16}e/cm^2$. However, $J_cs$ decreased as the dose increased further. The X-ray diffraction (XRD) analysis showed that the c axis of YBCO was elongated and the full width at half maximum (FWHM) increased as the dose increased, which is strong evidence of the atomic displacement by EB irradiation. The transmission electron microscopy (TEM) showed that the amorphous layer formed in the vicinity of the surfaces of the irradiated films. The amorphous phase was often present as an isolated form in the interior of the films. In addition to the formation of the amorphous phase, many striations running along the a-b direction of YBCO were observed. The high magnification lattice image showed that the striations were stacking faults. The enhancement of $J_c$ by EB irradiation is likely to be due to the lattice distortion and the formation of defects such as vacancies and stacking faults. The decrease in $J_c$ at a high EB dose is attributed to the extension of the amorphous region of a non-superconducting phase.

• 치과방사선
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• 제18권1호
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• pp.193-201
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• 1988

The purpose of this study was to investigate the variation in the length and shape of styloid processes and the relationships between the elongated styloid processes and the styloid process syndrome, using panoramic radiogrpahs and questionaires. The subjects were 342 patients consisted of 170 males and 172 females aged from 11 to 78 years, not showing facial asymmetry, who visited infirmary of dental college of Yonsei University. Also, the accuracy was determined for measuring the length of styloid processes from panoramic radiographs, using dried skulls. The results were as follows: 1. The length of styloid processes was magnified approximately 1.1 times, but there was no statistically significant differencies in the magnification rate of length between right and left side. 2. The mean radiographic length of styloid processes was 29.72±7.92㎜ in males, 27.93±6.69㎜ in females, and 28.82±7.37㎜ in total. And elongated styloid process (>30㎜) was seen in 31.3% of total subjects. 3. The growth in the length of styloid processes was completed in the third decade. 4. The most common shape of styloid processes was straight followed by segmented and bent form. The incidence of segmentation was reduced with increasing age. 5. The 74% of subjects with elongated styloid process (>30㎜) showed symptoms of the styloid process syndrome. The most frequent symptom was headache followed by discomfort in the neck when turning the head from left to right, tinnitus or earache, vague facial pain, discomfort or pain when swallowing, feeling that an object is caught in throat.