• 한국조경학회지
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• 제40권2호
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• pp.97-111
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• 2012

본 연구는 공공건설공사 중 조경공사 적산의 단가 비교로 적정 공사비 산출방안을 모색하고자 하였다. 2011년 상반기 실적단가에서 조경공사로 분류되는 12항목 중 유사기준인 7항목을 대비하며, 준용 공종은 5개 현장에 적용된 실적단가 80항목 중 비교 가능한 35항목을 유사기준인 2011년 3월의 표준품셈 단가로 대비하였다. 조경부문 7항목의 실적공사비율은 항목별로는 104.86%, 총공사비로는 92.09%이다. 실적공사비율이 높은 이유는 암반 적용 여부로 씨앗뿜어붙이기의 높은 비율도 있지만, 근본적인 이유는 잔디와 씨앗뿜어붙이기의 사면처리 비용 때문이므로, 품셈의 불합리성과 토양 종류별 기준별 보정계수 규정을 세분할 필요가 있다. 토목과 건축 준용부문 35항목의 실적공사비율은 항목별로 78.65%, 총공사비로는 71.31%(70.17%)이다. 이는 실적단가가 구조적으로 실제 금액을 반영하지 못하는 점과, 품셈은 인력시공에서 현실성이 결여된 때문으로 판단된다. 국토해양부 발표인 85.1~91.2%의 실적공사비율은 신규 전환품목 단가이므로, 이 결과는 실제적인 실적공사비율로 추정되며, 실적단가가 적정 비율을 보이도록 검증 후 보완하고 표준품셈도 이러한 실적자료 등으로 보완이 필요하다.

• 한국항공우주학회지
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• 제37권3호
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• pp.275-282
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• 2009

링레이저 자이로에는 입력각속도가 작은 영역에서 비선형적인 출력현상인 lock-in이 발생하는데 이를 제거하기 위하여 레이저 공진기에 정현파 각진동을 인가하는 방법이 주로 적용된다. 그러나, 그 방법을 적용하는 경우에도 각진동 회귀점에서 lock-in에 의한 오차가 남아있게 되는데, 이들 오차에 의하여 링레이저 자이로의 일반적인 오차특성인 랜덤웍이 발생된다. 이 lock-in에 의한 오차를 제거하기 위한 많은 연구결과 중의 한 방법으로써 lock-in오차 보상방법은 공진기 각진동 회귀점을 통과하기 전과 후의 맥놀이신호 주기를 비교하여 오차를 추정하고 보상하는 방법이다. 본 연구에서는 자이로 모델링 및 수치해석적인 방법으로, 이 lock-in오차 보상방법의 이론적인 적용 가능성을 분석하고, 현재 가능 할 것으로 판단되는 맥놀이 신호주기 측정 분해능을 감안하여 이 방법의 적용 효과를 분석하였다. 그 결과 lock-in오차 보상방법에 의하여 랜덤웍이 약 1/2~1/3로 감소될 수 있음을 알 수 있었다. 그러므로 이 방법은 항법장치의 정렬시간을 획기적으로 단축시킬 수 있는 방법이 될 것으로 기대된다.

• 한국진공학회지
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• 제20권3호
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• pp.225-232
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• 2011

다결정 실리콘 태양전지 표면의 광흡수율을 극대화시키기 위하여 플라즈마기반의 reactive ion etching (RIE) 공정을 적용하였으며 maskless 표면 texturing조건을 최적화하여 310~1,100 nm 파장대역의 평균 표면반사율을 $4{\pm}1%$ 내외로 감소시킬 수 있는 grass-like 한 블랙실리콘을 제조할 수 있었다. Saw damage를 가진 $15.6{\times}15.6\;cm^2$ bare 웨이퍼에서부터 중요 공정단계별로 처리된 시료들의 평균반사율, 표면형상, 소수운반자 수명 등의 위치분포를 측정하여 최종 제작된 태양전지의 광전변환효율과 외부양자효율 등과 비교 검토하여 고효율 다결정 실리콘 태양전지 양산에 필요한 표면 texturing 조건들을 연구하였다. 평균 반사율을 4% 이하로 감소시키는 texturing 공정조건에서 웨이퍼 중앙에서 가장자리로 갈 수록 표면구조의 깊이 2배 반치폭 3배의 불균일성이 발생하였으며 이에 따라 입사광자의 다중반사확률이 높아져 평균반사율이 1% 정도 낮아지는 것으로 밝혀졌다. 비반사막이 코팅된 시료에서 측정된 소수운반자수명분포도 중앙에서 가장자리로 갈수록 약 40% 이상 더 긴 수명을 갖는 것으로 밝혀져 표면구조의 크기에 따른 사이즈효과가 발생하는 것으로 판단된다. 제조된 태양전지의 위치에 따른 광전변환효율도 낮은 반사율과 더 긴 소수운반자수명을 갖는 가장자리에서 2% 가량 높은 광전변환효율을 보였으며, 380~1,100nm 파장대역의 외부양자효율 측정결과도 이를 뒷받침하고 있다. 균일한 에미터 층 형성 및 ARC 증착에 있어서 구조적으로 가장자리 부분의 구조가 유리한 것으로 예상되며, 동시에 표면 구조의 사이즈 효과 때문에 표면 재결합확률이 중앙보다 가장자리에서 더 감소되어 더 높은 광전변환효율을 보이는 것으로 해석된다.

• 대한핵의학회지
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• 제24권1호
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• pp.37-48
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• 1990

Detection of deep-seated abscesses is sometimes difficult with ultrasonogrpahy or computed tome graphy alone. Indium-111-labeled leukocyte has widely used in the localization of abscesses after introduction by Segal and Thakur in 1976. But there are some difficulties in using indium-111-oxine in our country because of hardness to get the radiopharmaceutical timely and long time for labeling leukocytes. So we peformed the indium-111-labeled leukocyte scan for establishment of the labeling procedure and clinical application. We labeled the mixed leukocytes from 36 ml of patient's blood using 4 ml of ACD solution, 7 ml of 6% hydroxyethyl starch solution $(HESPAN^{(R)})$, 1 mCi of indium-111 oxine, 5 ml of normal saline and centrifuge. It took about 2 hours for the preparation of radiolabeled leukocytes and attention for contamination was needed. The average injected dose of labeled mixed leukocytes was 465 uCi. The average number of injected leukocytes was $2.5\times10^8$ and the labeling ratio was $57{\pm}13%$ (Table 2, Fig. 5). These number and ratio were sufficient for the localization of abscess. About twenty per cent of indium was labeled to red blood cells and platelets (Fig. 6) and the half-life of injected radiolabeled leukocytes was 8.3 hours. Scan was performed in 9 patients who were suspected to have abscesses clinically or radiologically. Three patients were positive, in one patient who had abscess close to lower lumbar vertebrae was surgically drained and another 2 positive cases did not show abscess clearly on computed tomography, so only antibiotics were administrated and treated successfully. The negative 6 patients were improved without specific treatment. In conclusion, the use of indium-111 oxine labeled leukocytes for localization of abscesses were very specific and helpful in the decision of treatment considering its relatively simple labeling method, and could be easily performed providing timely supply of the radiopharmaceutical.

• 대한핵의학회지
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• 제21권2호
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• pp.167-174
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• 1987

Among noninvasive approaches for the evaluation of left ventricular performance, radionuclide ventriculography (RVG) has been shown to be of particular values. Phase analysis, recently introduced as more objective means for evaluating the temporal sequence of systolic ventricular wall motion than cine image of RVG comprises a pixel by pixel Fourier transformation of the time activity curve of a multiple gated acquisition equilibrium blood pool study. To examine the regional wall motion of ventricles in myocardial infarctions, we evaluated the phase image and histogram constructed for each ventricle by total phase angle range and full width of half maximum (FWHM). This study consisted of 7 normal subjects and 23 subjects with acute myocardial infarction. Contrast ventriculography and coronary angiography was performed in all partients with myocardial infarction. And we compared the result of phase analysis with cine image of RVG and examined the interrelationship between phase analysis and contrast ventriculography with coronary angiography. The results were as follows; 1) The total phase angle range and FWHM of LV phase histogram in myocardial infarction ($86^{\circ}\;and\;32^{\circ}$, repectively) were wider than those in normal control ($38^{\circ}\;and\;18^{\circ}$, respectively p<0.01). 2) RV phase angle range and FWHM in patients with right coronary artery (RCA) occlusion ($79^{\circ}\;and\;37^{\circ}$, respectively) were wider than those in normal control ($39^{\circ}\;and\;18^{\circ}$, respectively p<0.001) and the patients without RCA occlusion ($52^{\circ}\;and\;19^{\circ}$, respectively p<0.01). 3) Phase analysis was more sensitive (95%) than cine image of RVG (70%) for the detection of regional wall motion abnormality of LV.

• Structural Engineering and Mechanics
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• 제76권6호
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• pp.687-708
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• 2020

Openings in steel plate shear walls (SPSWs) are usually used for decorative designs, crossing locations of multiple utilities and/or structural objectives. However, earlier studies showed that generating an opening in an SPSW has a negative effect on the cyclic performance of the SPSW. Therefore, this study proposes tripling or doubling the steel-sheet-plate (SSP) layer and stiffening the opening of the SPSW to provide a solution to undesirable opening effects, improve the SPSW performance and provide the infill option of potential strengthening measures after the construction stage. The study aims to investigate the impact of SSP doubling with a stiffened opening on the cyclic behaviour, expand the essential data required by structural designers and quantify the SPSW performance factors. Validated numerical models were adopted to identify the influence of the chosen parameters on the cyclic capacity, energy dissipation, ductility, seismic performance factors (SPF) and stiffness of the suggested method. A finite Element (FE) analysis was performed via Abaqus/CAE software on half-scale single-story models of SPSWs exposed to cyclic loading. The key parameters included the number of SSP layers, the opening size ratios corresponding to the net width of the SSP, and the opening shape. The findings showed that the proposed assembly method found a negligible influence in the shear capacity with opening sizes of 10, 15, 20%. However, a deterioration in the wall strength was observed for openings with sizes of 25% and 30%. The circular opening is preferable compared with the square opening. Moreover, for all the models, the average value of the obtained ductility did not show substantial changes and the ultimate shear resistance was achieved after reaching a drift ratio of 4.36%. Additionally, the equivalent sectional area of the SSP in the twin and triple configuration of the SPSWs demonstrated approximately similar results. Compared with the single SSP layer, the proposed configuration of the twin SSP layer with a stiffened opening suggest to more sufficiency create SSP openings in the SPSW compared to that of other configurations. Finally, a tabular SPF quantification is exhibited for SPSWs with openings.

• 동남아시아연구
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• 제20권3호
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• pp.223-262
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• 2010

This paper has been written to find facts about the image of earth goddess broadly found in the Southeast Asia. The research findings are as follows: Firstly, the image of earth goddess wringing her hair is phenomenally discovered in both Buddhist temple murals and independent shrines in Thailand. This phenomenon is common in other Indochinese Buddhist countries such as Myanmar, Laos and Cambodia. Secondly, the life of Buddha including the story of the victory over Mara is found in such Buddhist canons as Mahavastu, Buddhacarita, Lalitavistara, Nidanakatha and Patamasambodhi. Among the canons, the story of the victory over Mara is described in differently ways. Earth becomes personified as the goddess in later version. The main cause to expel Mara's army also changes from sound to water. Patamasambodhi is most closely associated with the iconography of the earth goddess of Southeast Asia. Thirdly, Vessantara Jataka and Indian ancient customs tell us that a merit maker performs a rite of pouring water on the earth as an evidence for merit-making. This rite is a key to understanding the meaning of the scene where the earth goddess expels Mara's army into the flood by wringing her hair. The earth goddess is personified from the earth upon which the merit water is poured. Water soaked in her hair is the very holy water poured by the Buddha whenever he made a merit in his former lives. The amount of water flowed from the hair of the earth goddess representing the amount of his merit making was so huge and enough to defeat the Mara's army and for the Buddha to reach the Enlightenment. This legend explains the significance of the notion of merit in the Theravada Buddhist countries such as Thailand and Myanmar where the water pouring rites still take place and the images of the hair wringing earth goddess are commonly discovered. Fourthly, the first image of the earth goddess as the witness of merits for the Buddha appeared in some Gandharan Buddhist sculptures in the form of devotional gesture with her both hands pressed together and the upper half of her body above the ground. The appearance is in accordance with the description of her in the Lalitavistara canon. In later periods, the form changed into various types and finally the image of the earth goddess wringing her hair appeared in Southeast Asia around 11 century C.E. Some researchers argue this image form of the earth goddess shows the influence from China or India. However, the arguments are considered to be hypothetical as they have no strong evidence to prove. Finally, the modern image of earth goddess shows richer and more dynamic expression compared with its predecessors. Especially, outstanding is the standing earth goddess images found in the scene of the victory over Mara in many temple murals of central region of Thailand. The earth goddess in her voluptuous body shape is usually depicted as wringing her hair with her arms wide open in a posture of S curve. This appearance strongly reminds us of the postures of Salabhanjika and Tribhanga originated from Indian art. The adoption presumably has been made to signify her fertile and affluent characteristics.

• 한국문헌정보학회지
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• 제55권1호
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• pp.365-392
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• 2021

본 연구는 최근의 국내 문헌정보학 분야의 연구성과 현황과 경향을 파악하기 위하여 지난 18년간의(2002-2020) 국내(KCI) 6,301편의 학술논문데이터, 인용 수 26,474건과 국제(WoS) 86,727편의 학술논문데이터, 인용 수 1,196,961건을 수집하여 연구의 생산성과 영향력, 공동연구 경향과 연구주제분야 등을 비교 분석하였다. 그 결과, 국제와 국내 모두 저자의 생산성이 높으나 영향력은 상대적으로 낮았으며, 이러한 차이는 국제에서 더 극명하게 나타났으며, 일부 최상위 저자와 기관, 학술지에 생산성과 영향력이 편향되어있었다. 공동연구는 국제와 국내 모두 지속해서 증가하고 있었는데, 이러한 현상은 현대의 문헌정보학 연구가 과거보다 간 학문적이며 연구범위가 다각화되고 있음을 시사한다. 키워드 분석을 통해 국제가 국내보다 훨씬 다양한 주제로의 연구가 진행중임이 나타났으며, 인기 있는 연구주제가 반드시 영향력이 높은 것은 아님이 밝혀졌다.

• 대한약침학회지
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• 제25권3호
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• pp.216-223
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• 2022

Objectives: Oxidative stress plays a key role in chronic and acute brain disorders and neuronal damage associated with Alzheimer disease (AD) and other neurodegeneration symptoms. The neuroprotective effects of berberine and Berberis vulgaris (barberry) root extract against apoptosis induced by hydrogen peroxide (H₂O₂) in the human SH-SY5Y cell line were studied. Methods: The methanolic extraction of barberry root was performed using a maceration procedure. Oxidative stress was induced in SH-SY5Y cells by H₂O₂, and an MTT assay was applied to evaluate the neuroprotective effects of berberine and barberry root extract. The cells were pretreated with the half maximal inhibitory concentration (IC₅₀) of each compound (including berberine, barberry root extract, and H₂O₂), and the anti-apoptotic effects of all components were investigated using RT-PCR. Results: The SH-SY5Y cell viability increased in both groups exposed to 75 and 150 ppm barberry extract compared with that in the H₂O₂-treated group. The data showed that exposing SH-SY5Y cells to 30 ppm berberine significantly increased the cell viability compared with the H₂O₂-treated group; treatment with 150 and 300 ppm berberine and H₂O₂ significantly decreased the SH-SY5Y cell viability and was associated with berberine cytotoxicity. The mRNA levels of Bax decreased significantly under treatment with berberine at 30 ppm compared with the control group. A significant increase in Bcl-2 expression was observed only after treatment with the IC₅₀ of berberine. The expression level of Bcl-2 in cells exposed to both berberine and barberry extracts was also significantly higher than that in cells exposed to H₂O₂. Conclusion: The outcomes of this study suggest that treatment of SH-SY5Y cells with barberry extract and berberine could suppress apoptosis by regulating the actions of Bcl-2 family members.

• 한국분말재료학회지
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• 제30권4호
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• pp.324-331
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• 2023

Lithium (Li) is a key resource driving the rapid growth of the electric vehicle industry globally, with demand and prices continually on the rise. To address the limited reserves of major lithium sources such as rock and brine, research is underway on seawater Li extraction using electrodialysis and Li-ion selective membranes. Lithium lanthanum titanate (LLTO), an oxide solid electrolyte for all-solid-state batteries, is a promising Li-ion selective membrane. An important factor in enhancing its performance is employing the powder synthesis process. In this study, the LLTO powder is prepared using two synthesis methods: sol-gel reaction (SGR) and solid-state reaction (SSR). Additionally, the powder size and uniformity are compared, which are indices related to membrane performance. X-ray diffraction and scanning electron microscopy are employed for determining characterization, with crystallite size analysis through the full width at half maximum parameter for the powders prepared using the two synthetic methods. The findings reveal that the powder SGR-synthesized powder exhibits smaller and more uniform characteristics (0.68 times smaller crystal size) than its SSR counterpart. This discovery lays the groundwork for optimizing the powder manufacturing process of LLTO membranes, making them more suitable for various applications, including manufacturing high-performance membranes or mass production of membranes.