• 대한치과보철학회지
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• 제40권3호
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• pp.236-245
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• 2002

The acrylic resin was first introduced as denture base materials in 1937 and it is commonly used for denture base fabrication nowadays. Three different curing cycles (Conventional curing cycle, short curing cycle and long curing cycle) and three commercially available heat-activated acrylic resins (Vertex RS, Lucitone 199 and ProBase Hot) were investigated to find the curing cycle and material that showed the minimum shrinkage of the resin during polymerization process. A brass master mold was fabricated and duplicated by additional silicone impression material. Stone molds were made by pouring of type III dental stone (SILKY-ROCK YELLOW, Whip-Mix, Louisville, Kentucky). It was embedded in the flask. Strain gauge and thermocouple were embedded in the specimen. Strain gauge and thermocouple were connected to signal conditioning amplifier and data was recorded by pre-programmed software. The parameters ESmax (Maximum expansion strain), Sb (Strain measured just before deflasking procedure), Sa (Strain measured just after deflasking procedure) and Sf (Strain measured at the end of the experiment) were measured. ${\Delta}$S was calculated from Sb and Sa (${\Delta}$S=Sb-Sa). In the experiment concerned about materials, the parameters 90-ESmax (Maximum expansion strain measured during early 90 minutes of curing procedure), 180-ESmax (Maximum expansion strain measured from 90 minutes to 180 minutes), Sb, Sa, ${\Delta}$S and Sf were measured and the following conclusions were made. 1. The ESmax value of conventional curing cycle showed the largest value and the 180-ESmax value of Lucitone 199 showed the smallest value. 90-ESmax values showed no significant difference (p<0.05). 2. ${\Delta}$S values of conventional curing cycle showed the positive values. ${\Delta}$S values of short curing cycle and long curing cycle showed the negative values. All three materials cured by conventional curing cycle showed the positive values. 3. The Sf values of long curing cycle and ProBase Hot (cured by conventional curing cycle) showed the smallest values.

• 대한치과보철학회지
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• 제45권6호
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• pp.724-734
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• 2007

Statement of problem. Translucency and masking effect of provisional crown and fixed partial denture materials is an important esthetic consideration. But, provisional resin materials differ substantially in their ability to mask underlying colors. Purpose. The purpose of this study was to evaluate the translucency differences of provisional resin materials at various thicknesses and the correlation between the translucency and the masking efficiency. Material and methods. Two polymethyl methacrylate resins (Jet Tooth Shade, Alike) and three resin composites (Protemp 3 Garant, Luxatemp and Revotek LC) were used. Specimens (n=6) were fabricated from each material in 0.3, 0.5, 0.8, 1.0, 1.5, 2.0 and 3.0 mm thickness. The CIELAB parameters of each specimens were measured using a spectrophotometer. The translucency parameter (TP) values and the masking effect $({\Delta}ME^*{_{ab}})$ values were computed and all data were statistically analyzed by one-way ANOVA and the multiple comparisons Scheffe test. The correlation between the thickness and the TP values and the correlation between the thickness and the ${\Delta}ME^*{_{ab}}$ values were also evaluated by correlation analysis and regression analysis. Results. The TP values and the ${\Delta}ME^*{_{ab}}$ values were significantly related to the thickness in all specimens. The TP values were more sensitive to the change of thickness than the ${\Delta}ME^*{_{ab}}$ values. The order of the translucency by brand was different from the order of the masking effect by brand in all thickness groups. Conclusion. Within the limitations of this study, the translucency and masking effect of the provisional resin materials investigated were significantly related to their thickness. The masking effect of provisional resin was correlated with the translucency parameter, but the order of the masking effect by brand was different from the order of the translucency parameter.

• 대한방사선기술학회지:방사선기술과학
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• 제42권6호
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• pp.429-434
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• 2019

The gonads are directly affected by radiation exposure during radiography of the pelvis, abdomen, and spine. Exposure of the gonads to radiation can cause genetic mutations and can result in the occurrence of malignant tumors. In this study, we created three types of shielding material shapes for shielding of the ovaries, which are the gonads of female during radiography of the pelvis, and comparative evaluations using shadow shielding methods. The source surface distance(SSD) was 100 cm and the field size was 42 cm × 43 cm. The three types of shielding material shapes(type 1, 2 and 3) were assessed and the entrance surface dose in the ovaries were measured. The thickness of the shielding material was expanded from 0.3 mm to 2.4 mm and after five repetitions, radiation values were measured and mean values were calculated. The mean dose were 3.09 mGy for type 1, 3.54 mGy for type 2, and 3.19 mGy for type 3, indicating that the measurements were the lowest for type 1. When an additional filter of 0.2 Cu + 1 Al was used, the dose were 3.72 mGy for type 1, 5.43 mGy for type 2, and 4.05 mGy for type 3, indicating that the measurements were the lowest for type 1. The results show that, even if the shielding material is not thick, in other words, even with a thickness of 2.94 mGy for the SN 3(0.9 mm) of type 1, shielding can be achieved, with a patient dose lower than the diagnostic reference level(3.42 mGy). Additionally, among the three types of shielding material, the type 1 appeared to be the most appropriate shielding material. It is thought that the use of shielding material could reduce the risk factors for stochastic effects or critical effects of ionizing radiation during pelvic or lumbar radiography.

• 한국심리학회지 : 문화 및 사회문제
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• 제24권3호
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• pp.385-410
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• 2018

물질주의 가치 추구는 한국인의 정신건강 및 심리적 안녕감을 이해하는 데 중요한 변인일 수 있다. 이 연구는 물질주의 연구를 활성화하고 신뢰로운 측정을 하고자 물질주의 가치 척도로 가장 자주 사용되는 Richins와 Dawson(1992)의 물질주의 가치 척도(Material Values Scale)를 한국어로 번안하여 타당화하기 위해 실시하였다. 연구 1은 번안한 한국판 물질주의척도의 요인구조를 확인하고 신뢰도 및 타당도를 검증하였다. 이를 위해 대학생 417명(표본 1)을 대상으로 확인적 요인분석을 실시하였고, 그 결과 원척도의 요인과 동일한 3요인을 확인하였다. 원척도가 제시한 하위요인을 한국어로 번역하여 성공판단, 소유중심, 행복추구라 명명하였다. 이 과정에서 요인부하량이 낮은 3개의 문항은 물질주의 가치 척도의 다른 언어로의 타당화 연구를 참조하여 삭제하였고, 총 15문항으로 한국판 물질주의척도를 구성하였다. 연구 2에서는 표본 1과 유사한 성격을 지닌 대학생 650명(표본 2)을 대상으로 한국판 물질주의척도를 검증한 결과 수렴 및 변별타당도, 동시타당도, 예측타당도가 양호한 것으로 밝혀졌다. 또한 경제활동을 하는 직장인 392명(표본 3)과 대학생(표본 2)을 대상으로 다집단 요인분석을 실시한 결과 한국판 물질주의척도를 대학생과 직장인에게 동일하게 사용할 수 있는 것으로 나타났다. 직장인(표본 3)을 대상으로 검증한 결과 예측타당도가 양호한 것으로 나타났다. 여자 대학생 408명(표본 4)을 대상으로 6개월 간격으로 설문을 실시한 결과 검사-재검사 신뢰도 또한 양호한 수준으로 확인되었다. 이러한 결과는 한국판 물질주의척도가 성인을 대상으로 한 개인의 물질주의 가치 수준을 신뢰롭고 타당하게 평가하는 도구임을 의미한다.

• 한국측량학회지
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• 제35권1호
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• pp.23-30
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• 2017

NDVI (Normalized Difference Vegetation Index) plays an important role in surface land cover classification and LST (Land Surface Temperature Extraction). Its characteristics do not full carry the information of the surface cover typically in urban areas even though it is widely used in analyses in urban areas as well as in vegetation. However, abnormal NDVI values are frequently found in urban areas. We, therefore, examined NDVI values on whether NDVI is appropriate for LST and whether there are considerations in NDVI analysis typically in urban areas because NDVI is strongly related to the surface emissivity calculation. For the study, we observed the influence of the surface settings (i.e., geometric shape and color) on NDVI values in urban area and transition features between three land cover types, vegetation, urban materials, and water. Interestingly, there were many abnormal NDVI values systematically derived by the surface settings and they might influence on NDVI and eventually LST. Also, there were distinguishable transitions based on the mixture of three surface materials. A transition scenario was described that there are three transition types of mixture (urban material-vegetation, urban material-water, and vegetation-water) based on the relationship of NDVI and LST even though they are widely distributed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.561-562
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• 2006

The purpose of this study was to investigate the root cause of adhesion of silica and ceria particles during Poly-Si, TEOS, and SiN CMP process, respectively. The zeta-potentials of abrasive particles and wafers were observed negative surface charges in the alkaline solutions. SAC and STI patterned wafers have intermediate values of their composition surface's zeta potentials. The theoretical interaction force and adhesion force of silica and ceria particle were calculated in solution with acidic, neutral and alkaline pH. A stronger attractive force was calculated for silica and ceria particles on wafers in acidic solutions than in alkaline solutions. The theoretical interaction forces of the SAC and STI patterned wafers have intermediate values of their constitution wafer's values. The adhesion forces is observed lower values in alkaline solutions than in acidic solutions. And the ceria particle has lower adhesion than that of the silica particle.

• 한국생활과학회지
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• 제19권3호
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• pp.537-553
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• 2010

Culture represents forms of life appeared in various dimensions. Advertisements which represent these forms of life show the most important social and cultural phenomenon. The necessity of research on the cultural characteristics of society has been raised because the effectiveness of advertisement could have been varied depending on the cultural value. Moreover, within a society, values reflected by advertisements tend to vary in different eras. Thus, this study aims to clarify the differences between cultural values from different eras through an analysis of cultural characteristics and symptoms with consideration of the time flow. This study also examines the meanings of cultural characteristics highlighted by the study. For the investigation, two Korean women's magazines were selected, from 1955 to 2008. Data were analyzed using chi-squared test which was conducted with Crosstab using the PASW statistics 17.0 Program. The results were as follows: there were changing aspects from traditional values to modern values by years. Additionally, each period was described using several keywords. The keywords were divided by decade: in the '50s keywords were 'lifestyle change', 'material value increase' and the 'challenge to traditional values', in the '60s keywords were 'American culture acceptance', 'material success', in the '70s keywords were 'the rise of nonmaterial value', 'rationalism' and 'egalitarianism', in the '80s 'individualism', 'Life style and culture group differentiation', 'conspicuous consumption', in the '90s 'globalization', 'emphasis on personality sensitivity', 'health-oriented', 'improve the quality of life', while in the '00s keywords were 'spread of digital life', 'rational consumption patterns', 'the 3rd distribution'. Through the research, important changes in the cultural characteristics of Korea were observed. Furthermore, we may be able to think of the most effective way of advertising by identification of the cultural characteristics of the society.

• 한국연초학회지
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• 제26권2호
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• pp.126-134
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• 2004

Tobacco dust samples were collected for two times in primary and secondary process at 4 cigarette manufacturing factories(Shintanzin, Youngju, Wonju, Kwangju) and analyzed to evaluate usage as a raw material in production of reconstituted tobacco. The chemical constituents and HWS of tobacco dust were analyzed. Tobacco dust samples were partitioned by particle size using a series of screens ranging from 20 to 200 mesh. The amount of material retained in each fraction was quantified and sand content was also determined. Appreciable average amounts$(40-65\%)$ material at 4 locations were found to be larger than 60 mesh. Although the amount of material in each fraction increased to a maximum at 100 mesh and then decreased, the $\%$ sand continually increased with decreasing particle size. The chemical constituents and HWS content of tobacco dust have similar values in secondary process of 4 cigarette manufacturing factories but the those of primary process have different values according to the site of occurrence and manufacturing factories.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 춘계학술대회 논문집
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• pp.85-87
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• 1993

We have investigated three polyene systems, $X-(-HC=CH-)_n-Y$, where X/Y=H/H, $F/CH_3$, and $NH_2/NO_2$. We estimated asymptotic values (for $n=\infty$ of the electronic properties with $logA=a_o+a_1/(n+1)+a_2/(n+1)^2+a_3/(n+1)^3$, so that the cases n=0 can be included in that equation. Here, A can be $\mu$, $\beta$, $\alpha/(n+1)$ or $\gamma/(n+1)$. For these asymptotic values. the SCF results are more reliable due to the higher level of theory, while the PM3 results can give better trend with more data for polyene systems with longer chain length.

• Nuclear Engineering and Technology
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• 제53권3호
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• pp.911-919
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• 2021

In this paper, the design stress intensity values for the plate-type fuel assembly for research reactor are presented. Through a tensile test, the material properties of the cladding (aluminum alloy 6061) and structural material (aluminum alloy 6061-T6), in this case the yield and ultimate tensile strengths, Young's modulus and the elongation, are measured with the temperatures. The empirical equations of the material properties with respect to the temperature are presented. The cladding undergoes several heat treatments and hardening processes during the fabrication process. Cladding strengths are reduced compared to those of the raw material during annealing. Up to a temperature of 150 ℃, the strengths of the cladding do not significantly decrease due to the dislocations generated from the cold work. However, over 150 ℃, the mechanical strengths begin to decrease, mainly due to recrystallization, dislocation recovery and precipitate growth. Taking into account the uncertainty of the 95% probability and 95% confidence level, the design stress intensities of the cladding and structural materials are established. The presented design stress intensity values become the basis of the stress design criteria for a safety analysis of plate-type fuels.