• 한국과학교육학회지
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• 제13권2호
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• pp.282-295
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• 1993

This study was accomplished to survey of current situation and management of science education in the special classroom(school) managed by firm. The status of management and the evalution of the scientific inquiry ability were taken on workers attending 17 Special Classes and 9 Special Schools located in Taegu City and Kyungpuk Province. As a responses, most students chose the subject "Science"as an option within their limited 8 units credits. About 88.5% of the students were female. About 78.3% of the classes/schools were conducted in the evening only. About 59.4% of teaching staffs were prevailed with female in these classes, and most of them were young, naive, and unexperienced with their major in chemistry and physics. Insufficient facilities and equipments, crowded classes, understaffed instructors, and inappropriated text materials. etc., were reasons for the students not receiving maximum benefit from these classes and schools. In order to evaluate of scientific inquiry ability, 25 items were constructed and administered to 250 students. The processes of scientific inquiry were classified into 5 categories(category I : establishing a subjects, category II : planning a experiments, category III : conducting a experiments. category IV : interpreting a result of experiments, category V : formulating generalization). As the result obtained from the achivement test analysis, the scores for all the students were significantly low, and the scores for girls were higher than those for boys. The results of test in the selected students showed that inquiry abilities in the category I, II and V were higher than those in category III and IV.

• 한국세라믹학회지
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• 제40권12호
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• pp.1189-1196
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• 2003

Sol-gel법으로 강유전성 B $i_{3.25}$L $a_{0.75}$ $Ti_3$ $O_{12}$ (BLT) stock solution을 합성하고 Pt/Ti $O_2$/ $SiO_2$/Si 기판위에 스핀코팅법으로 BLT 박막을 증착하였다. 본 실험에서는 Bi(TMHD)$_3$, La(III)2-Methoxyethoxide, Ti(IV)i-propoxide를 출발물질로 사용하였으며 2-Methoxyethanol을 용매로 사용하였다. 급속열처리(RTA)가 BLT 박막의 결정성장을 촉진시키기 위해 사용되었고, RTA를 실시한 시편과 RTA를 실시하지 않은 시편의 전기적 특성을 비교하였다. RTA를 실시한 후 72$0^{\circ}C$에서 로 열처리 한 BLT 박막의 경우 5V 인가 전압 하에서 2Pr 값은 RTA를 실시하지 않은 경우보다 27% 증가한 20.46$\mu$C/$ extrm{cm}^2$이었다.

• 대한소아치과학회지
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• 제25권1호
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• pp.76-92
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• 1998

The purpose of this study was to evaluate the possible efficacy of Nd-YAG laser as a dentin conditioner by observing the laser irradiation dentin surface under scanning electron micrograph and measuring shear bond strength of restored light-cured glass ionomer mold. Fifty intact premolars were prepared for shear bond strength tests. The teeth were randomly divided into five groups as follows; Group I. no treatment Group II. 10% poly acrylic acid, 20 sec Group III. laser treatment 2 w, 20 Hz, 2 sec Group IV. laser treatment 2 w, 20 Hz, 5 sec Group V. laser treatment 2 w, 20 Hz, 10 sec Samples of each group were restored with light-cured glass ionomer cement after dentin conditioning and then measuring the shear bond strength of each specimen were measured using universal testing machine. Additional ten premolars were prepared for SEM analysis The result from the this study can be summarized as follows. 1. Shear bond strength of polyacrylic acid-treated group (II) was significantly higher than other groups (p<0.05). 2. No statistically significant difference could be found between three laser-treated groups (III, IV, V) in shear bond strength(p>0.05) 3. According to the result of observation under SEM, Polyacrylic acid was shown to have removed the smear layer effectively and opened the dentinal tubules, whereas the laser has produced the irregular surface mainly composed of melted and fused structure. The microcracks found in laser-treated groups increased in number with irradiation time and formed the regular mesh-type in 10 sec-irradiation group. 4. The ultrastructural change of dentin surface created by laser irradiation was found to the improper for bonding of the glass ionomer restorative materials. And the lower shear bond strength of laser irradiated group might have been due to the failure to form the suit able dentin surface for the glass ionomer to penetrated into and form the proper micromechanical retention.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.24-24
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• 2003

Research activity in the III-V nitrides materials system has increased markedly in the past several years ever since high-brightness blue light-emitting diodes (LEDs) became commercially available. Despite of excellent optical properties of the GaN, however, inherently poor thermal property of the sapphire used as a substrate material n these devices may lead to thermal degradation of devices, especially during their high power operation. Therefore, dependable thermal analysis and packaging schemes of GaN-based LEDs are necessary for solid lighting applications under high power operation. In this paper, emphasis will be placed upon thermal design of GaN-based LEDs. Thermal measurements of LEDs on chip and packaging scale were performed using the liquid crystal thermographic technology and micro thermocouples for different bias conditions. By a series of optical arrangement, hot spots with specific transition temperatures were obtained with increasing input power. Thermal design of LEDS was made using the finite element method and analytical unit temperature profile approach with optimal boundary conditions. The experimental results were compared to the simulated data and the results agree well enough for the establishment of dependable prediction of thermal behavior in these devices. The paper will present a more detailed understanding of the thermal analysis of the GaN-based blue and white LEDs for high power applications.

• 대한화장품학회지
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• 제30권3호
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• pp.419-426
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• 2004

나노 세라마이드의 캡슐화(Nano-ceramide capsulation)는 세라마이드 III와 토코페릴리놀레이트를 나노 크기의 모노 베지클에 캡슐화시켜 피부각질층에 작용하도록 만든 기술이다. 그 제조에는 고압 마이크로플루다이저를 사용하였으며 조성은 다음과 같다. 모노 베지클의 막 강화제로서 $0.5{\~}5.0\;wt\%의$ 수소첨가레시친과 $0.1{\~}2.0\;wt\%의$ 리소레시친을 사용하였으며, 용제로서 $5.0{\~}10.0\;wt\%의$ propylene glycol과 $5.0{\~}10.0\;wt\%의$ ethanol을 사용하였다. 피부 보습기능과 아토피 치료를 위하여 활성성분인 세라마이드 III와 토코페릴리놀레이트를 사용하였으며 유화제는 함유하지 않았다. 나노 세라마이드 캡슐기술의 최적조건은 다음과 같다. 마이크로플루다이저의 통과압력은 1,000 bar, 통과횟수는 3회, 통과 온도는 $60{\~}70^{\circ}C가$ 적당하였다. 또한, nano capsule의 pH는 $5.8\pm0.5이었다.$ 평균입자크기는 $63.1{\pm}7.34 nm로$ 물과 같은 투명한 성상을 보였으며, 제타포텐셜값은 $-55.1{\pm}0.84mV이었다.$ 임상실험 결과로서, 피부보습효과(in-vivo, n=8, p-value<0.05)는 비교시료보다 $21.15{\%}$ 개선되었으며, 치료 전보다는 $36.31{\%}$ 개선되었다. 더구나, 아토피 피부 효과는 아토피 피부 환자 10명에게서 양성반응을 보였다.

• Clinical and Experimental Reproductive Medicine
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• 제30권4호
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• pp.333-340
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• 2003

Objective: This study was performed to examine the maturation and the development to the blastocyst stage of immature oocytes collected from patients with high risk of ovarian hyperstimulation syndrome (OHSS). Materials and Methods: Cumulus-oocyte complexes (COCs) were collected following only HCGpriming for non stimulated IVF-ET cycles of the patients. At the time of oocyte collection, COCs were classified into three groups in accordance with their appearance (Group I: oocytes with dispersed cumulus cells; Group II: oocytes with compacted cumulus cells; Group III: oocytes with sparse cumulus cells). The in vitro maturation and blastocyst development rates of the COCs were compared among these groups. From August 2001 to June 2002, 48 IVM/IVF-ET cycles from 42 patients (mean age: $32.4{\pm}3.8$ years) were performed. To prevent the occurrence of OHSS, the patients were primed with 10, 000 IU HCG alone 36 h before oocyte collection without gonadotropin stimulation. Oocytes were aspirated on cycle days from 7 to 13. The normal COCs were classified into three groups according to their appearance. The aspirated immature oocytes were cultured in YS maturation medium containing 30% (v/v) human follicular fluid (HFF), 1 IU/ml FSH, 10 IU/ml HCG and 10 ng/ml rhEGF. Fertilization was induced by intracytoplasmic sperm injection (ICSI). All zygotes were co-cultured with cumulus cells in $10{\mu}l$ YS medium containing 10% HFF until day 7 after oocyte collection. Blastocyst transfer was performed on day 5 after ICSI. Results: Th e mean number of oocytes cultured in the IVM/IVF cycles was $24.7{\pm}10.6$. Of 1185 COCs, those assigned to Group I, II and III were 470 (39.7%), 414 (35.0%) and 301 (25.4%), respectively. The maturation rate (94.5%, 444/470, p<0.05) in Group I was significantly higher than those of Group II (62.8%, 260/414) and Group III (73.1%, 220/301). Especially, 30.9% of COCs in Group I (145/470) was matured on the day of oocyte aspiration. There were no differences in the rates of fertilization and cleavage among the three groups. The development rate to the blastocyst stage in Group I (54.6%, 206/377, p<0.05) was also significantly higher than those in Group II (33.0%, 68/206) and Group III (30.1%, 52/173). Twenty-four clinical pregnancies (50.0%) was obtained and 22 pregnancies (45.8%) are ongoing. Implantation rate in the present study was 24.6%. Conclusion: These results suggest that there is a positive correlation between the appearance of COCs and the developmental competence of the immature oocytes in non stimulated IVM/IVF cycles.

• 대한지역사회영양학회지
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• 제11권6호
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• pp.740-749
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• 2006

The objective of this study was to develop nutrition education materials for older adults, 'nutritional management for healthy aging'. A booklet and four leaflets were developed based on lesson plans. Topics of the lesson plans included eating habit assessment. Korean food guide pyramid, meal planning, eating sensibly and weight management. The titles of the leaflets were 'Eating right for healthy aging', 'Eat calcium-rich foods', 'Enjoy fruits & vegetables' and 'Weight management'. Illustrations and icons appropriate to the texts were designed using illustrator 9.0 and Photoshop 6.0. Booklet (letter size, 5 chapters, 44 pages) and leaflets (B4 size, 6 sections) focused on modifying undesirable eating habits, providing practical tips for desirable behaviors, and behavioral modification such as recording in a food diary, goal setting and increasing self-efficacy. The drafts were pilot-tested by interviews with older adults(n=10), and minor changes were made. The characteristics of revised materials are as follows; i) materials focused on providing desirable eating behaviors for healthy aging, ii) messages were simple and specific, iii) large fonts(13 pt) were used and materials included interesting pictures and illustrations, iv) materials provided tips for balanced diets and recipes fur older adults, v) materials included sections for participation of learners including assessment of nutritional risk factors and obesity, meal planning and games. The revised materials are self-explanatory and can be used by older adults and in nutrition education for older adults.

• The Journal of Advanced Prosthodontics
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• 제11권2호
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• pp.128-137
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• 2019

PURPOSE. The aim of this study was to compare the effect of different finishing and polishing techniques on water absorption, water solubility, and microhardness of ceramic or glass-polymer based computer-aided design and computer-aided manufacturing (CAD/CAM) materials following thermocycling. MATERIALS AND METHODS. 150 disc-shaped specimens were prepared from three different hybrid materials and divided into five subgroups according to the applied surface polishing techniques. All specimens were subjected up to #4000 grit SiC paper grinding. No additional polishing has been done to the control group (Group I). Other polishing procedures were as follows: Group II: two-stage diamond impregnated polishing discs; Group III: yellow colored rubber based silicone discs; Group IV: diamond polishing paste; and Group V: Aluminum oxide polishing discs. Subsequently, 5000-cycles of thermocycling were applied. The analyses were conducted after 24 hours, 7 days, and 30 days of water immersion. Water absorption and water solubility results were analyzed by two-way ANOVA and Tukey post-hoc tests. Besides, microhardness data were compared by Kruskal-Wallis and MannWhitney U tests (P<.05). RESULTS. Surface polishing procedures had significant effects on water absorption and solubility and surface microhardness of resin ceramics (P<.05). Group IV exhibited the lowest water absorption and the highest microhardness values (P<.05). Immersion periods had no effect on the microhardness of hybrid ceramic materials (P>.05). CONCLUSION. Surface finishing and polishing procedures might negatively affect physical properties of hybrid ceramic materials. Nevertheless, immersion periods do not affect the microhardness of the materials. Final polishing by using diamond polishing paste can be recommended for all CAD/CAM materials.

• Journal of Radiation Protection and Research
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• 제48권2호
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• pp.68-76
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• 2023

Background: In the process of discussion on the possibility of using radionuclide-contaminated soil and debris generated by radiation disasters, a strategy for the proper management of radiation exposure protection while considering the source of the contaminated materials is necessary. Materials and Methods: The radiological protection criteria that are likely to be applied to the source-related approach based on the International Commission on Radiological Protection recommendations and the International Atomic Energy Agency safety standards are summarized. We proposed five interpretations of radiation protection to contribute to the promotion of discussion on the possibility of using a part of low-level-radionuclide-contaminated soil and debris in the post-accident rehabilitation. Interpretations I to III are based on the idea of "using a reference level to protect the public in post-accident rehabilitation," whereas IV and V are based on the idea of "using the dose constraint to protect the public in the post-accident rehabilitation when the sources are handled in a planned activity." The former idea is subdivided into three based on the definition of the source, which is managed by the reference level, and the latter idea is divided into two depending on whether or not additional dose from using contaminated materials is deemed acceptable. Results and Discussion: To confirm the applicability of the five interpretations presented, we suggested the concrete values of protection criteria via two feasible cases. In this case study, we proposed radiation protection by the dose constraint based on the Interpretation IV and chose 1 mSv/yr for the public and 20 mSv/yr for workers dealing with radionuclide-contaminated materials. Conclusion: We concretely and systematically demonstrated how the concept of radiation protection can be applied to the process of discussion on the possibility of using radionuclide-contaminated materials within the framework of an international system of protection. This study's findings can provide necessary information to discuss the possibility of using radionuclide-contaminated materials as an alternative option for recovery and reconstruction after a radiation disaster from the viewpoint of radiation protection.

• 한국작물학회지
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• 제28권3호
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• pp.345-350
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• 1983

일정한 재배조건에서 생산된 38종의 유색 대두종실을 공시하여 종실의 화학적 조성과 Texturometer를 이용한 취반에 따른 물리적 변이를 분석 조사한 결과 다음의 경향을 알 수 있었다. 1. 대부분의 유색 대두는 황태에 대한 기존의 재래종 대두 분석결과보다 단백질과 지방의 함량이 낮고 상대적으로 탄수화물 함량이 높은 경향이었으나 종실중의 차이에 따른 종실성분의 변이는 일정하지 않았다. 2. 100립중이 25-30g인 대립군의 유색 대두종은 단백질, 지방 및 탄수화물의 함량에서 상대적으로 높은 변이계수를 나타내었다. 3. 유색 대두의 Texturometer curve에서는 Hardnes, Cohesiveness, Elasticity만 반응을 보였고, Hardness는 종실중에 의하여, 기타의 Parameter들은 종실중 자체에 의하여 달라서 동일한 특성이나 종실중 내에서도 품종에 따라 유의적 차이를 보였다. 4. Hardeness와 Elasticity는 낮은 C. V치를, Cohesiveness와 Gumminess 및 Chewiness는 40% 이상의 높은 C.V.치를 나타내었다. 5. Hardness, Elasticity, Chewiness는 상호간에 정상관을 보이는 반면 이들과 Cohesiveness, Gumminess간에는 부의 상관을 보였다. 6. Hardness와 Elasticity는 탄수화물 함량과 정상관을 단백질 함량과는 역상관을 보였으며 Cohesiveness는 이들과 정반대의 경향을 나타내었다.