• 반도체디스플레이기술학회지
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• 제9권3호
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• pp.75-78
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• 2010

In this study we investigated the electrical properties of ZnO-based MOS capacitor with $HfO_2$ as the gate dielectric. MIM capacitor, which uses either $HfO_2$ or $Al_2O_3$ as the dielectric layer, is also studied to understand the dependency of the dielectrics on the preparation conditions. It was found that thinner $HfO_2$ films yield better electrical properties, namely lower leakage current and higher breakdown electric field. These properties were observed to deteriorate when subsequently annealed. Capacitance in the depletion region of MOS capacitor was found to increase with UV ozone treatment time up to 60min. However, when the treatment time was extended to 120min, the trend is reversed. The 'threshold voltage' was also observed to positively shift with UV ozone treatment time up to 60min. The shift apparently saturated for longer treatment.

• 한국잠사곤충학회지
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• 제55권2호
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• pp.44-53
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• 2019

Sericin has been removed in textile industry to improve the luster and hand of silk textile. Therefore, the sericin was considered as useless material. However, recently sericin has attracted researcher's attention since unique properties of sericin including high water retention, UV protection, and wound healing effect were reported. In spite of the useful properties of sericin as biomedical and cosmetic materials, its poor mechanical properties have restricted its industrial use in biomedical and cosmetic fields. To improve the mechanical properties, various sericins were prepared by different conditions, and the effects of the preparation condition on the structure and properties of sericin were examined. In this review paper, research trend in the structure and properties of sericin prepared with different conditions were intensively introduced.

• Bulletin of the Korean Chemical Society
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• 제6권6호
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• pp.329-333
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• 1985

A procedure for the preparation of peptizable pseudoboehmite has been described in detail based upon a process of neutralization of an aqueous aluminum sulfate or chloride solution with aqueous ammonia. In order to obtain peptizable pseudoboehmite products, carefully controlled conditions were required in the whole processes of neutralization, aging, washing, and drying. The optimum conditions experimentally found are the following. The aluminum salt solution is neutralized with aqueous ammonia until the final pH of the solution reaches 10.0 to 10.8 or 9.0 to 9.3 for the sulfate of chloride, respectively. The alumina gel formed is subjected to aging at $80^{\circ}C for about 3 hours and washed with water more than 5 times to reduce the residual sulfate or chloride ion in the final products to less than 4%. The pseudoboehmite gel thus obtained should be dried oven at 80 to $100^{\circ}C for a few to several hours depending on the selected temperatures.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.973-978
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• 2002

This study was performed to verify the effect of various testing conditions affecting measured compressive strength of concrete core and to compute the correction coefficients for it. Conditions of specimens affecting test results include size(diameter), height-diameter ratio, humidity of specimen, amount and arrangement of bar, core direction from structure and method of end preparation. In testing core strength of concrete, special cares should be taken on various testing conditions whose effects have been latent in conventional concrete.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2003년도 somma/kms meeting
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• pp.220-220
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• 2003

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 춘계학술발표회요약집
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• pp.269.2-269
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• 2001

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 1998년도 추계학술발표회 초록집
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• pp.33-34
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• 1998

• 가족자원경영과 정책
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• 제16권2호
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• pp.123-143
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• 2012

This study, based on a health belief model, examines how baby boomers perceive health and how they are financially preparing for future medical expenses. In addition, the study analyzes which factors influence baby boomers' preparation behaviors for future medical expenses and their perceived sufficiency of the preparation for medical expenses. Through such activities, this study examines baby boomers' current preparation status for future medical expenses, and based on this outcome, will turn the attention of individuals and society toward becoming more concerned with health and increasing health expectancy. For this study, an online survey was conducted targeted at men and women who were born between 1955 and 1963 and live nationwide, and its resultant data were collected. After conducting a 15-day survey in November 2011, a total of 418 questionnaire responses were used for the final analysis. The major findings of this study and their implications are as follows: First, baby boomers' health beliefs and their perceptions of health identified by subjective health conditions were very positive. Second, while there were some partial differences in the influencing factors, health beliefs and perceived health influenced the sufficiency of future medical expenses in the three groups, which were segmented according to how they prepare for future medical expenses-insurance-based, pension-based, and insufficiently prepared groups. Third, the baby boomers selected the national health insurance as the primary means of preparing for post-retirement medical expenses, and backed it up with private health insurance or the national pension. In addition, when baby boomers' perceived sufficiency of future medical expenses were examined, 57.6% of the respondents expressed that their old-age medical expenses were not sufficient. Fourth, in terms of baby boomers' preparation behaviors for future medical expenses, it was revealed that as one recognizes old-age health more seriously, he/she has a higher chance of using insurance and lower chance of using a pension to prepare for medical expenses. Fifth, regarding baby boomers' sufficiency of preparations for future medical expenses, economic factors such as total assets, the sufficiency of retirement assets, and the number of insurance policies, as well as health perceptions, including health beliefs and subjective health conditions, were important influencing factors.

• Applied Microscopy
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• 제42권1호
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• pp.49-52
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• 2012

For TEM study of biological samples or polymers that are contained in organic structure, it is often required that the sample is prepared by using ultramicrotome and stained with proper agents to increase the contrast of organic structure. In this study, we investigated an efficient TEM sample preparation method for ductile heterogeneity material by using ultramicrotomy. Cryo-ultramicrotomy is a suitable method that is capable of rendering sample hardness for various ductile materials. However, it has several factors to consider, such as experimental cost, working time and finding the optimal staining conditions. To satisfy these considerations, we prepared TEM sample by using ultramicrotome without cryofunction, and secured the sample hardness by applying the staining process prior to ultrathin sectioning. The cross-linked polyethylene structure in the sample was stained with the 2% $RuO_4$ solution in a sealed test tube for 24 hours at $4^{\circ}C$. After the sample staining, ultrathin sections of sample were prepared using ultramicrotome. As a result, it was revealed that the difficulties associated with staining of ultrathin sections prepared by low-temperature conditions were improved. In addition, appropriate staining depth of sample could be selected for sectioning process. The quality of TEM sample obtained by using this method was better than that of cryo-ultramicroscopy. Finally, it is expected that our method could be effectively applied in TEM sample preparation for a variety of nano-bio convergence materials.

• 한국재료학회지
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• 제18권2호
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• pp.92-97
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• 2008

In spray pyrolysis, the effects of the preparation temperature, flow rate of the carrier gas and concentration of the spray solution on characteristics such as the morphology, size, and emission intensity of $Ca_8Mg(SiO_4)_4Cl_2:Eu^{2+}$ phosphor powders under long-wavelength ultraviolet light were investigated. The phosphor powders obtained post-treatment had a range of micron sizes with regular morphologies. However, the composition, crystal structure and photoluminescence intensity of the phosphor powders were affected by the preparation conditions of the precursor powders. The $Ca_8Mg(SiO_4)_4Cl_2:Eu^{2+}$ phosphor powders prepared at temperatures that were lower and higher than $700^{\circ}C$ had low photoluminescence intensities due to deficiencies related to the of Cl component. The phosphor powders with the deficient Cl component had impurity peaks of $Ca_2SiO_4$. The optimum flow rates of the carrier gas in the preparation of the $Ca_8Mg(SiO_4)_4Cl_2:Eu^{2+}$ phosphor powders with high photoluminescence intensities and regular morphologies were between 40 and 60 l/minute. Phosphor powders prepared from a spray solution above 0.5 M had regular morphologies and high photoluminescence intensities.