• The korean journal of orthodontics
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• v.20 no.2
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• pp.267-280
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• 1990

The purpose of this study was to investigate the force mechanism of Multiloop Edgewise Arch Wire and the intensity and distribution of stresses with vertical and intermaxillary elastics. The obtained results were as follows. 1. When plain wires were inserted and vertical and intermaxillary elastics were used in the upper and lower arch, the stresses of the anterior and posterior ends of wires were observed greatly but the stresses of the premolar were very small. 2. When MEAW were inserted in upper and lower arch, the upper 1st and 2nd premolar and the lower 1st premolar were extruded greatly. 3. In the area of the upper 1st molar and the lower 2nd premolar and the lower 1st molar, any stresses were not observed. 4. The vertical elastic counteracted the intrusion force of the MEAW in the anterior teeth but could not affect on posterior teeth. Using with the Class II elastics, the distal tipping force and extrusion force were exerted in the upper anterior teeth and the intrusion forces of the lower anterior teeth were relieved. Using with the Class III elastics, the extrusion force were exerted in the upper and lower anterior teeth, the distal tipping force were increased in the lower posterior teeth. 5. The Class II elastic counteracted the anterior intrusion force of the MEAW and extruded and tipped mesially the lower 2nd molar. The intrusion force of the MEAW also could not overcome the extrusion force of the class II elastics. 6. When the Class III elastics were engaged, the upper 2nd molar was extruded in spite of the intrusion forces of the MEAW and the extrusion forces of the lower anterior teeth and distal tipping forces in the posterior teeth were observed.

• Journal of Oriental Neuropsychiatry
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• v.17 no.3
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• pp.11-19
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• 2006

Objective : This study was to investigate the utility and relation of dementia rating test(K-DRS and IADL, NPI-Q(symptom), NPI-Q(suffering), CCDR, SDS Method : For this study, we carried out dementia assessment examination of 34 patients with memory disturbance who have come to Cheongju oriental hospital of Daejeon university from April 2005 to February 2006. This study classified the patients as none-dementia(ND), questionable dementia(QD), and dementia(DA) groups and analyzed the result of examination. Results: 1. K-DRS and SDS, K-DRS and SDS, NPI-Q(symptom) and NPI-Q(suffering), NPI-Q(symptom) and CCDR showed clear correlations statistically each other. 2. K-DRS scores showed the significant differences from that of ND and the other groups ; attention and conceptualization showed the significant differences between ND and DA, management and memorization showed the significant differences between DA and the other groups. 3. IADL scores showed the significant differences from that of DA and the other groups, NPI-Q(symptom) scores showed the significant differences between QD and DA, NPI-Q(suffering) scores showed no differences among all groups. 4. CCDR scores showed the significant differences from that of DA and the other groups, SDS scores showed the significant differences between ND and DA 5. MMSE- K and K-DRS showed strong correlations statistically each other. Conclusion : The study results suggest that dementia rating tests is useful to esteem the dementia and the dementia rating tests have strong corelations each other. We use the above mentioned tests for correct diagnosis.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.116-116
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• 2009

마그네슘 합금은 구조용으로 사용 가능한 금속 재료 중 가장 가벼운 소재이며, 동시에 비강도 및 비강성과 같은 기계적 특성이 우수하여 알루미늄 합금의 뒤를 이을 차세대 경량 재료로써 주목을 받고 있다. 더욱이 석유자원의 대부분을 소비하고 있는 운송기기 분야에서는 경량화를 통한 연비향상과 배출가스 저감이 가장 큰 과제이며, 이 문제를 해결하기 위한 노력의 일환으로 최경량 소재인 마그네슘 합금의 사용량은 더욱 증가할 것으로 기대된다. 한편 기존의 마그네슘 합금 관련 연구는 새로운 합금의 개발에 치우쳐 있었으며, 상대적으로 이들 합금을 활용하기 위한 가공기술, 특히 용접에 대한 연구는 아직까지 많이 부족한 실정이다. 이는 철강재와 비교하여 마그네슘 합금의 고유물성이 용접의 관점에서는 상당히 열악하기 때문으로, 마그네슘은 융점 및 비점은 낮은 반면, 증기압과 열전도율은 높고 표면장력 및 점성은 낮은 특성을 가지고 있다. 그러므로 타 공법에 비해 상대적으로 입열이 적고 고속용접이 가능한 레이저의 적용이 최적으로 판단된다. 따라서 본 연구에서는 Nd:YAG 레이저를 사용하여 압연판재로 상용화되어 있는 AZ31B 마그네슘 합금의 맞대기 용접성을 조사하였으며, 용접부의 미세조직과 용접조건에 따른 용접부의 기계적 특성을 비교 및 검토하였다. 용접부의 기계적 특성은 인장 및 경도시험을 통해 평가하였다. 그 결과 레이저 출력 1.2kW를 적용한 경우에 안정적인 강도를 얻을 수 있었으며 레이저 출력 1.5kW, 용접속도 80mm/sec의 조건에서 모재 인장강도 대비 103% 그리고 연신율 대비 47.1%의 최적의 결과가 얻어졌다. 또한 용접부의 경도는 모재와 동등하거나 다소 높은 수준이었다. 이는 용접시 용접부내 잔류하는 알루미늄에 의한 고용 강화 효과와 금속간화합물의 석출 빈도 증가, 그리고 레이저 용접의 특징인 급열급랭 공정에 기인한 결정립 미세화의 영향 때문으로 사료된다. 한편 용접부 미세조직을 관찰한 결과, 열영향부의 존재는 두드러지지 않았으며 용융경계부에서는 주상정이, 그리고 용접부 가운데에서는 등축정이 관찰되었다.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.1
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• pp.23-32
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• 2005

This experiment was carried out to determine on the growth characteristics, yield and palatability in mono-cropping(T1; sorghum $\times$ sudagrass hybrid, T2; soybean) and inter-cropping[T3; sorghum $\times$ sudagrass hybrid(1) + soybean(2)]. The results obtained are summarizes follows; In plant length. leaf length, leaf width and stem diameter of sorghum $\times$ sudagrass hybrid(SSH). T3(1) was lower than T1 at 1st cutting time. But in 2nd and 3rd cutting time. T3(1) was higher than T1 Stem diameter of T2 was higher than soybean of T3(2). but plant length, leaf length and leaf width of T2 were higher than T3(1). The leaf ratio of SSH in T3(1) was higher than T1 in the first cutting time, but T3(1) was higher than T1 at 2nd and 3rd cutting time. The number of tiller of T1 was higher than SSH of T3(1) at 1st cutting time, but T3(1) was higher than T1 at 2nd and 3rd cutting time. Dead stubble rate of SSH in T3(1) showed a little lower value than T1. Dry matter and fresh yield of T1 was higher than T2 and T3. But protein yield of T3 was higher than T1 The palatability of 1st cutting time was 100.0. 76.8 and $18.5\%$ on T2, T3 and T1, respectively.

• Imaging Science in Dentistry
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• v.37 no.1
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• pp.27-33
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• 2007

Purpose : The research was done to investigate the effectiveness of 2D bony morphometry and microstructure of micro-computed tomography (micro-CT) on the osteoporotic bony change. We performed the bone morphometric analysis of proximal femur in ovariectomized rabbits with BMD and micro-CT examination. Materials and Methods : Twenty-one female (Newzealand, about 16 weeks old, 2.9-3.4kg) rabbits were used. Three rabbits were sacrificed on the day when experiment began (Baseline). The remaining 18 rabbits were divided into two groups. One group was ovariectomized bilaterally (OVX) and the other animals were subjected to sham operation (Sham). Bone specimens were obtained from the right and left femur of sacrificed rabbits. At intervals of 1, 2, 3, 5, 6 months respectively, BMD tests were performed on the proximal femur by using PIXlmus 2 (GE Lunar Co. USA), 2-dimensional bone morphometric analysis by custome computer program and 2D/3D bone structure analysis by micro-CT (Skyscan 1072, Antwerpen, Belgium). Statistical analysis was carried out for the correlation between bone morphometry, micro-CT and BMD Result : BV/TV, Tb.Th, Tb.N of micro-CT parameters showed higher values in sham group than OVX group. N.Nd/Ar.RI, N.NdNd, N.NdTm, N. TmTm, PmB/Ar.RI, 3-D BoxSlope of 2D morphometric parameters showed higher values in Sham group than OVX group. The micro-CT parameters of Tb.Sp, Tb.N were statistically significant correlated with BMD respectively. Several 2D morphometric parameters were statistically significant correlated with BMD respectively. Conclusion : Several parameters of 2D bony morphometry and micro-CT showed effective aspects on the osteoporotic bony change.

• Corrosion Science and Technology
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• v.8 no.4
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• pp.143-147
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• 2009

In biomedical implants and dental fields, titanium has been widely utilized for excellent corrosion resistance and biocompatibility. However, Ti and its alloys are nonbioactive after being implanted in bone. In this study, for the purpose of improvement in biocompatibility the anodic $TiO_2$ layer on Ti-xNb alloys were fabricated by electrochemical method in phosphate solution, and the effect of Nb content on the pore size, the morphology and crystallinity of Ti oxide layer formed by the anodic oxidation method was investigated. The Ti containing Nb up to 3 wt%, 20 wt% and 40 wt% were melted by using a vacuum furnace. The sample were cut, polished, and homogenized for 24 hr at $1050^{\circ}C$ for surface roughness test and anodizing. Titanium anodic layer was formed on the specimen surface in an electrolytic solution of 1 M phosphoric acid at constant current densities ($30mA/cm^2$) by anodizing method. Microstructural morphology, crystallinity, composition, and surface roughness of oxide layer were observed by FE-SEM, XRD, EDS, and roughness tester, respectively. The structure of alloy was changed from $\alpha$-phase to $\beta$-phase with increase of Nb content. From XRD results, the structure of $TiO_2$ formed on the Ti-xNb surface was anatase, and no peaks of $Nb_2O_5$ or other Nb oxide were detected suggesting that Nb atoms are dispersed in $TiO_2$-based solid solution. Surface roughness test and SEM results, pore size formed on surface and surface roughness decreased as Nb content increased. From the line analysis results, intensity of Ti peak was high in the center of pore, whereas, intensity of O peak was high in the outside of pore center.

• Journal of East-West Nursing Research
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• v.14 no.1
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• pp.5-13
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• 2008

Purpose: The study was to identify the relationship among perceived stress, coping strategies and satisfaction f clinical experience in nursing students and to examine difference of grade. Methods: A total 238 nursing students (second grade: 141 students, third grade: 97 students) from K. Womens' College were provided with self reported questionnaires from July 26, 2006 to July. 30, 2006. Perceived stress was measured using Perceived Stress Scale. Coping was measured using Coping Responses Inventory-Adult form. Satisfaction of clinical experience was measured using Satisfaction Inventory. The data were analyzed by descriptive statistics, t-test, ANOVA and Pearson's Correlation Coefficient with SPSS 12.0 program. Result: Participants showed that a high level of perceived stress score $2.71{\pm}.47$ of total 4 (2nd grad) and $2.67{\pm}.35$ of total 4 (3rd grade). Approach Coping Scales score of coping strategies was $68.19{\pm}6.06$ (2nd grade), $63.38{\pm}6.69$ (3rd grade) of total 96, then coping mechanism's mean among 2nd grade nursing students was higher than 3rd grade nursing students. Satisfaction score of clinical experience in 2nd grade nursing students was $3.01{\pm}.32$ and higher than 3rd grade ($2.99{\pm}.38$). There was a negative correlation r=-.264 (p=.000) between perceived stress during clinical practice and satisfaction. It was statistically significant. There was a positive correlation r=.154 (p<.05) between satisfaction score of clinical experience in nursing students and approach coping scales score. Conclusion: With these findings, we found that the more approach coping level, the more satisfaction of clinical practice. It is needed to developing effective teaching method and coping strategies for nursing students to improve their coping ability and prepare qualified nursing profession.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.296-296
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• 2007

Ferroelectric neodymium-substituted $Bi_4Ti_3O_{12}$(BTO) thin films have been successfully deposited on Pt/Ti/$SiO_2$/Si substrate by a sol-gel spin-coating process and the effect of crystallization temperature on their microstructure and ferroelectric properties were studied systematically. $Bi(TMHD)_3$, $Nd(TMHD)_3$, $Ti(O^iPr)_4$ were used as the precursors, which were dissolved in 2-methoxyethanol. The thin films were annealed at various temperatures from 600 to $720^{\circ}C$ in oxygen ambient for 1 hr, which was followed by post-annealed for 1 hr after depositing a Pt electrode to enhance the electrical properties. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the crystallinity and surface morphology of layered perovskite phase, respectively. The crystallinity of the BNT films was improved and the average grain size increased as the crystallization temperature increased from 600 to $720^{\circ}C$ at an interval of $40^{\circ}C$. The polarization values of the films were a monotonous function of the crystallization temperature. The remanent polarization value of the BNT thin films annealed at $720^{\circ}C$ was $24.82\;{\mu}C/cm^2$ at an applied voltage of 5 V.

• Korean Journal of Agricultural Science
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• v.46 no.3
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• pp.497-506
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• 2019

The aim of this study was to estimate the factors that can be used as a predictive indicator of antler productivity in elk. Body weight and antler data from 115 stags raised at the Animal Genetic Resources Research Center in Korea were used in this study. The function for the average antler weight was derived by age, which was $y=-3.4693+5.3747x-0.8x^2+0.0424x^3$, and $R^2$ was 0.991. The analysis of the relationship between body weight at birth and the 1st and 2nd year and the antler weight after the 2nd year showed a correlation between them. There was a correlation between the antler weight of 1 and 2 year old stags and the weight of 2 year old stags as well; especially, both antler weights for the 1st and 2nd year were highly correlated with the antler weight of the 4th year. However, there was no relationship between the antler main beam length for the 1st and 2nd year and the antler weight after the 3rd year. Therefore, it is expected that a large amount of antler will be obtained in the future if proper management is carried out for young deer from birth to 2 years old. Additionally, the results of this study are expected to be useful for the development of a deer breeding program and the deer industry.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.861-869
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• 2020

This study was conducted to investigate the suitability of frozen oysters as a raw material for the preparation of seafood products by measuring the concentrations of harmful microorganisms and chemicals in thawed flesh. The microbial concentrations in thawed oysters were 2.3-5.0 log CFU/g for viable cell counts, not detected (ND)-1.0 log CFU/g for coliform bacteria, and ND for Escherichia coli and pathogenic bacteria such as Staphylococcus aureus, Salmonella spp., Listeria monocytogenes, Vibrio parahaemolyticus, Enterohemorrhagic Escherichia coli (EHEC), and Clostridium perfringens. In frozen oysters, the heavy metal concentration for viable cell counts was ND-0.030 mg/kg, for lead was ND-0.393 mg/kg, and for cadmium was 0.021-0.597 mg/kg. Benzo(a)pyrene, shellfish poison (paralytic shellfish and diarrhetic shellfish poisons), and radioactivity were not detected in the thawed oysters. These results suggest that frozen oysters can be safely used as a raw material for the preparation of seafood products.