• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.122-122
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• 1999

Graphite with its advantages of high thermal conductivity, low thermal expansion coefficient, and low elasticity, has been widely used as a structural material for high temperature. However, graphite can easily react with oxygen at even low temperature as 40$0^{\circ}C$, resulting in CO2 formation. In order to apply the graphite to high temperature structural material, therefore, it is necessary to improve its oxidation resistive property. Silicon Carbide (SiC) is a semiconductor material for high-temperature, radiation-resistant, and high power/high frequency electronic devices due to its excellent properties. Conventional chemical vapor deposited SiC films has also been widely used as a coating materials for structural applications because of its outstanding properties such as high thermal conductivity, high microhardness, good chemical resistant for oxidation. Therefore, SiC with similar thermal expansion coefficient as graphite is recently considered to be a g행 candidate material for protective coating operating at high temperature, corrosive, and high-wear environments. Due to large lattice mismatch (~50%), however, it was very difficult to grow thick SiC layer on graphite surface. In theis study, we have deposited thick SiC thin films on graphite substrates at temperature range of 700-85$0^{\circ}C$ using single molecular precursors by both thermal MOCVD and PEMOCVD methods for oxidation protection wear and tribological coating . Two organosilicon compounds such as diethylmethylsilane (EDMS), (Et)2SiH(CH3), and hexamethyldisilane (HMDS),(CH3)Si-Si(CH3)3, were utilized as single source precursors, and hydrogen and Ar were used as a bubbler and carrier gas. Polycrystalline cubic SiC protective layers in [110] direction were successfully grown on graphite substrates at temperature as low as 80$0^{\circ}C$ from HMDS by PEMOCVD. In the case of thermal MOCVD, on the other hand, only amorphous SiC layers were obtained with either HMDS or DMS at 85$0^{\circ}C$. We compared the difference of crystal quality and physical properties of the PEMOCVD was highly effective process in improving the characteristics of the a SiC protective layers grown by thermal MOCVD and PEMOCVD method and confirmed that PEMOCVD was highly effective process in improving the characteristics of the SiC layer properties compared to those grown by thermal MOCVD. The as-grown samples were characterized in situ with OES and RGA and ex situ with XRD, XPS, and SEM. The mechanical and oxidation-resistant properties have been checked. The optimum SiC film was obtained at 85$0^{\circ}C$ and RF power of 200W. The maximum deposition rate and microhardness are 2$mu extrm{m}$/h and 4,336kg/mm2 Hv, respectively. The hardness was strongly influenced with the stoichiometry of SiC protective layers.

• 콘크리트학회논문집
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• 제29권2호
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• pp.169-177
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• 2017

북한은 최근 핵무기의 일반적인 열, 폭풍, 방사능 피해가 아닌 전자 장비를 무력화시키기 위한 고고도 전자기파 탄을 개발 중인 것으로 예측되고 있다. 현재 군용 목적으로 사용되고 있는 HEMP 차폐 시설 중 차폐 판의 경우 전자파 차폐 효과가 뛰어난 금속 판이 사용되고 있으나 이러한 금속판들은 차폐 시설 제작 시 용접 부위에서의 전자파 유입 가능성 등 시공상의 어려움과 높은 비용이 문제시 되고 있는 실정이다. 이에 본 연구에서 차폐 시설을 따로 구축하지 않고 콘크리트 구조물 자체로써 전자파 차폐 효과를 확보하기 위하여 콘크리트 실험체에 전기전도성이 높은 재료를 혼입하였다. 또한, 실험체 중 가장 높은 차폐효과를 보인 2가지 수준과, 가장 낮은 차폐 효과를 보인 2가지 수준에 $100{\mu}m$ 아연-알루미늄 합금 금속용사 피막을 적용하였다. 실험 결과 전기전도성이 높은 재료를 혼입한 실험체는 MIL-STD-118-125-1 규격 최소 차폐 기준을 만족하지 못하였으나, 금속용사 피막을 적용한 실험체에서는 모두 최소 차폐 기준을 만족하였다. 결론적으로, $100{\mu}m$ 아연-알루미늄 합금 금속용사 피막이 HEMP 차폐에 높은 효율성을 가지고 있다고 판단된다.

• 한국조경학회지
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• 제33권6호
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• pp.98-108
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• 2006

The climate of urban area is an unstable type with considerable seasonal variation in precipitation wind speed, and temperature and it grows worse. Besides, ozone is a serious air pollutant in most of large cities. So worldwide, some of large cities are investing in forestry options to offset their climate problems, but lack of information has hindered comparisons of urban un cost effectiveness to other options. This research intends to study the economic benefits of tree shading of 19 parking lots in UCD campus. The economic benefits of tree shading are air conditioning savings, air quality, stormwater run-off, and other benefits. Especially, this study focuses how much the economic benefit of parking lot shading has been increased from 1995 to 2003 year by aerophoto. Some data on dimensions of parking lots and the number, size, tree species, and location of trees around each parking lot was inventoried. Two aerophotos(1995,2003) were used in order to analyze the increasement of tree canopy in 19 parking lots for 8 years. However, increasing coverage of trees and managing them for healthy growth would not be sufficient for avoiding adverse impacts by future climate change. Additional measures should be followed such as an increase of energy use efficiency and development of substitute energy. For example, coverage of trees help to save cooling energy by blocking solar radiation reaching parking cars and building structures through shading, and creating cool micro-climates through evapotranspiration. They also reduce heating demand by decreasing air infiltration and heat conduction out of the interior of buildings. Proper arrangement of vegetation over the parking lots can reduce cooling and heating costs. So proper planting design around hard space paving including species selection and location can significantly save cooling and heating energy. And a reduction in car and building's heating and cooling costs results in the reduction in energy demand which causes to emissions of air pollutants. Total increased tree canopy from 1995 to 2003 is $8,470.45m^2$ and the economic benefits is US$ 5,282.10. The economic benefit of one tree has been US$ 7.21 for 8 years. And an annually increased benefit is US$ 0.9 per a tree. If this kind of study is applied to studying the economic benefits of tree canopy in parking lots of Korea, it could result in guidelines of tree planting of parking lots. Because the trees selected for planting in parking lots were not suitable for an environment, the guidelines should contain a recommended list of trees. The guidelines should propose the shading percentage of parking lot when we plan a parking lot and contain the maintenance of trees in order to maximize the economic benefits of tree canopy.

• Asian Pacific Journal of Cancer Prevention
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• 제16권13호
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• pp.5297-5304
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• 2015

Background: The Pakistan Atomic Energy Commission Cancer Registry (PAECCR) program has made availability of a common cancer incidence database possible in Pakistan. The cancer incidence data from nuclear medicine and oncology institutes were gathered and presented. Materials and Methods: The cancer incidence data for the last 30 years (1984-2014) are included to describe a data set of male and female patients. The data analysis concerning occurrence, trends of common cancers in male and female patients, stage-wise distribution, and mortality/follow-up cases is also incorporated for the last 10 years (2004-2014). Results: The total population of provincial capital Lahore is 9,800,000. The total number of cancer cases was 80,390 (males 32,156, females 48,134). The crude incidence rates in PAECCR areas were 580.8/$10^5$ during 2010 to 885.4/$10^5$ in 2014 (males 354.1/$10^5$, females 530.1/$10^5$). The cancer incidence rates for head and neck (15.70%), brain tumors (10.5%), and non-Hodgkin lymphoma (NHL, 9.53%) were found to be the highest in male patients, whereas breast cancer (46.7%), ovary tumors (6.80%), and cervix (6.31%) cancer incidence rates were observed to be the most common in female patients. The age range distribution of diagnosed and treated patients in conjunction with the percentage contribution of cancer patients from 15 different cities of Punjab province treated at the Institute of Nuclear Medicine and Oncology, Lahore are also included. Leukemia was found to be the most common cancer for the age group of 1-12 years. It has been identified that the maximum number of diagnosed cases were found in the age range of 51-60 years for males and 41-50 years for female cancer patients. Conclusions: Overall cancer incidence of the thirty years demonstrated that head and neck and breast cancers in males and in females respectively are the most common cancers in Punjab province in Pakistan, at rates almost the highest in Asia, requiring especial attention. The incidence of brain, NHL, and prostate cancers among males and ovarian and cervix cancers among females have increased rapidly. These data from a major population of Punjab province should be helpful for implementation of appropriate planning, prevention and cancer control measures and for determination of risk factors within the country.

• Asian-Australasian Journal of Animal Sciences
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• 제20권3호
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• pp.316-327
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• 2007

In this study, a Korean native cattle strain (Hanwoo) evidencing high performance in terms of both meat quality and quantity was employed in the generation of 150,000 BAC clones with an average insert size of 140 kb, and corresponding to about a 6X coverage of bovine chromosomal DNA. The BAC clones were pooled in a mini-scale via three rounds of a pooling protocol, and the efficiency of this pooling protocol was evaluated by testing the accuracy of accessibility to the positive clones, via a PCR-based screening method. Two sets of primers designed from each of two known genes were tested, and each yielded 2 or 3 positive clones for each gene, thereby indicating that the BAC library pooling system was appropriate with regard to the accession of the target BAC clones. Analyses of $3.3{\times}10^6$ base pairs obtained from the 7,090 BAC end sequence (BES) showed that 34.88% of the DNA sequence harbored the repetition sequence. Analysis of the 7,090 BES to the $1^{st}$ and $2^{nd}$ generation radiation hybrid map of the cattle genome, using the COMPASS program designed for the construction of a cattle-human comparative mapping, resulted in the localization of a total of 1,374 clones proximal to 339 $1^{st}$ generation markers, and 1,721 clones proximal to 664 $2^{nd}$ generation markers. Collectively, the BAC library and pooling system of the BAC clones from the Korean cattle, coupled with the chromosome-localized BAC clones, will provide us with novel tools for the excavation of desired clones for genome mapping and sequencing, and will also furnish us with additional information regarding breed differences in cattle.

• Asian Pacific Journal of Cancer Prevention
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• 제15권14호
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• pp.5691-5696
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• 2014

Background: Many clinical trials have been conducted to evaluate sorafenib for the treatment of advanced NSCLC, but the results for efficacy have been inconsistent. The aim of this study was to evaluate the efficacy and safety of sorafenib in patients with advanced NSCLC in more detail by meta-analysis. Methods: This meta-analysis of randomized controlled trials (RCTs) was performed after searching PubMed, EMBASE, ASCO Abstracts, ESMO Abstracts, and the proceedings of major conferences for relevant clinical trials. Two reviewers independently assessed the quality of the trials. Outcomes analysis were disease control rate (DCR), progression- free survival (PFS), overall survival (OS) with 95% confidence intervals (CI) and major toxicity. Subgroup analysis was conducted according to sorafenib monotherapy, in combination with chemotherapy or EGFR-TKI to investigate the preferred therapy strategy. Results: Results reported from 6 RCTs involving 2, 748 patients were included in the analysis. Compared to sorafenib-free group, SBT was not associated with higher DCR (RR 1.31 (0.96- 1.79), p=0.09), PFS (HR 0.82 (0.66-1.02), p=0.07) and OS (HR 1.01 (0.92-1.12), p=0.77). In terms of subgroup results, sorafenib monotherapy was associated with significant superior DCR and longer PFS, but failed to show advantage with regard to OS. Grade 3 or greater sorafenib-related adverse events included fatigue, hypertension, diarrhea, oral mucositis, rash and HFSR. Conclusions: SBT was revealed to yield no improvement in DCR, PFS and OS. However, sorafenib as monotherapy showed some activity in NSCLC. Further evaluation may be considered in subsets of patients who may benefit from this treatment. Sorafenib combined inhibition therapy should be limited unless the choice of platinum-doublet regimen, administration sequence or identification of predictive biomarkers are considered to receive better anti-tumor activity and prevention of resistance mechanisms.

• Journal of Oral Medicine and Pain
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• 제36권1호
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• pp.21-24
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• 2011

구강건조증이란 주관적인 구강 내 건조감으로 정의되며, 이는 약물, 타액선 질환, 방사선 치료, 쉐그렌 증후군, 심리적 요인 등과 같은 다양한 원인에서 비롯된다. 구강 건조증 환자 중 현저한 타액선 기능 감소가 존재하는 경우 구강캔디다증, 치아우식증, 치주질환, 미각변화, 구취 등의 병발증이 나타날 수 있다. 이러한 구강건조증의 치료로는 우선적으로 구강건조를 유발하는 원인요소를 제거하거나, 환자의 불편감을 감소시키기 위한 대증요법이 주가 되며 실제로 타액 분비 기능이 감소된 경우 이로 인한 합병증을 예방하기 위한 치료와 타액분비를 자극할 수 있는 약물치료를 시행할 수 있다. 이 중 타액분비를 촉진시키는 약물인 필로카핀은 구강건조증 치료제로 널리 사용되어 왔다. 하지만 발한작용, 비뇨기 및 위장관계의 비정상적인 기능유도, 심혈관계 및 호흡기계에 대한 위험 등의 부작용이 있어 천식, 만성폐질환, 심혈관계 질환자에게는 주의 깊은 사용이 요구되며, 특히 조절되지 않는 천식환자의 경우 필로카핀의 절대적 금기증으로 사용이 금지된다. 이처럼 구강건조증 치료에 있어 필로카핀은 부작용으로 인해 전신적인 투여에 많은 제한이 있다. 따라서, 필로카핀의 부작용을 최소화하기 위해 국소적으로 사용되는 방법 중의 하나인 필로카핀 양치액을 이용하여 치료한 증례를 통해 그 효과를 확인해보고자 하였다.

• 대한의용생체공학회:의공학회지
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• 제39권1호
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• pp.48-54
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• 2018

In this study, We developed a Ancillary device for child radiography for X-ray of children under 5 years old and verified its effectiveness. Chest X-rays of children younger than 5 years of age were performed by Supine method at the position of Table detector, Short - Source to Image Receptor Distance(SID). Existing Supine and Short -SID imaging methods cause many problems, such as errors in image reading and excessive radiation exposure dose to patients, but the use of an Ancillary device for child radiography(ADCR) solves these problems. A total of 160 children were divided into the Upright group using ADCR and Supine group without ADCR. The chest X-ray image was visually evaluated by two radiologists with reference to the European Commission's List of Quality Criteria for Diagnostic Radiographic Images in Pediatrics. The total score of the qualitative evaluation was 5.15% higher in the chest upright method using ADCR than in the chest supine method without ADCR, and the chest upright method score was higher than that of the chest supine method in items 1 to 7. whether infants have deep inspiration or not, 4.87% higher for item 1, whether infants rotate or not and the degree of tilting, 0% higher for the item 2, the reproduction of image from just above apices of lungs to T12/L1, 0% for the item 3, reproduction of the vascular pattern in central 2/3 of the lungs, 6.92% higher for the item 4, reproduction of the trachea and the proximal bronchi, 12.9% higher for the item 5, visually sharp reproduction of the diaphragm and costo-phrenic angles, 10% higher for the item 6, reproduction of the spine and paraspinal structures and visualisation of the retrocardiac lung and the mediastinum, and 3.65% higher for the item 7. Items 2 and 3 showed no statistically significant differences(P > 0.05), and items 1, 4, 5, 6, and 7 showed statistically significant differences(P < 0.05). In conclusion, Upright method using ADCR in pediatric chest X-ray is considered as a good alternative to existing Supine method.

• 대한방사선기술학회지:방사선기술과학
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• 제39권4호
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• pp.607-614
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• 2016

토모를 이용한 회전 방사선치료 시 2차원적인 선량분포 평가 대신 3차원적 선량분포 평가의 필요성에 관하여 연구하였다. 토모 치료 부위의 정확한 선량분포를 측정하기 위하여 RANDO phantom을 이용하였으며, 평가 대조군으로 gafchromic EBT2 필름의 선량분포와 3차원 체적팬텀인 ArcCHECK phantom을 이용하여 3차원적인 선량분포를 gamma correction(3%/3 mm, 2%/2 mm)으로 평가하였다. 팬텀에 대한 치료 영역은 각각 0.5, 1, 1.5, 2, 2.5, 3 cm로 설정하였으며, 처방선량을 1,200 cGy로 하여 5회씩 선량을 조사하였다. Gafchromic EBT2 필름을 이용한 절대선량 측정 시 평균오차는 $0.76{\pm}0.59%$이었으며, ArcCHECK phantom을 이용한 절대선량 측정 시 평균오차는 $1.37{\pm}0.76%$로 나타났다. 선량분포의 평가에서 gafchromic EBT2 필름인 경우 gamma correction(3%/3 mm)은 평균 $97.72{\pm}0.02%$, ArcCHECK phantom인 경우 평균 $99.26{\pm}0.01%$로 측정되었다. 또한 gafchro mic EBT2 필름에서 gamma correction(2%/2 mm)의 평균은 $94.21{\pm}0.02%$이며, ArcCHECK phantom에서는 평균은 $93.02{\pm}0.01%$로 측정되었다. 토모치료를 이용한 환자 DQA에서 3차원 체적팬텀인 ArcCHECK phantom을 이용한 선량분포 평가가 cheese phantom을 이용한 선량분포 평가에 비하여 치료영역 주변부에 대한 정확한 측정과 실시간 평가가 가능하므로 환자의 치료가 보다 더 정확하고 빨리 이루어질 수 있을 것으로 사료된다.

• 대한방사선기술학회지:방사선기술과학
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• 제40권3호
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• pp.371-376
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• 2017

소아의 경우 방사선의 감수성이 성인에 비하여 높고, 잠재적 피폭으로 인한 장해가 발생할 수 있으므로 피폭선량에 대해 관리가 요구된다. 이에 본 연구는 소아 흉부검사 시 산란선을 제거시켜주지만 피폭선량을 증가시키는 격자(Grid)의 사용 유, 무에 따른 영상과 거리와 조건의 변화에 따른 영상을 분석하여 소아 흉부검사에서 적정한 검사조건을 제시하고자 하였다. 연구방법은 Grid를 부착한 상태에서 100 cm, 180 cm에서 측정하였으며, kVp를 70. 90. 110으로 변화하여 측정하였다. 또한 Grid를 미부착한 상태에서 100 cm, 180 cm을 고정 시키고, 선량을 6, 8, 10 mAs로 변화시켜 측정하였으며, 측정항목은 신호 대 잡음비, 대조도 대 잡음비, J.J Vucich를 측정하였다. kVp를 고정시켜 측정한 결과 초점-이미지 수용체간 거리가 100 cm일 때 신호 대 잡음비, 대조도 대 잡음비, J.J Vucich가 모두 높게 나타났다. 또한, 선량(mAs)을 변화시켜 측정한 결과 신호 대 잡음비, 대조도 대 잡음비, J.J Vucich에서 초점-이미지 수용체 간 거리 100 cm에서 높게 나타났다. 현재 국내에서 흉부검사는 일반적으로 180 cm으로 시행하고 있지만 본 연구결과에서는 소아의 흉부 검사 시 초점-이미지수용체간 거리가 100 cm일 때 영상평가에서 화질이 높게 평가되었다.