多地域 負荷周波數 制御에 依한 動的負荷狀態 推定機構의 效果

裵相賢,丁采榮,李雄基,金蘭 조선대학교 기초과학연구소 1989 自然科學硏究 Vol.12 No.1

This paper presents a method to design pseudo decentralized load frequency control(LFC) based on digital controllers which improves dynamic responses in multi-area power systems by incorporating computational time delay. Assuming that the amplitude of the load fluctuation is small and invariant, behavior of the power system in expressed by a set of linear differential equation, with constant coefficients. First, in order to synthesize a sampled date controller, the system is digitalized at appropriate sampling period by using numerical approximation method. Next, the centralized control gains incorporating time delay are determined based on the optimal theory. In order to damp a constant disturbance, we make use to digital servo system having one controller delay. From the point of view of application to LFC problem, the area control error (ACE) is chosen as output variables of servo system.

Magnetoelectricity in multiferroic hexaferrites as understood by crystal symmetry analyses

Chai, Yi Sheng,Chun, Sae Hwan,Cong, Jun Zhuang,Kim, Kee Hoon American Physical Society 2018 Physical review. B Vol.98 No.10

학령전기 아동과 어머니의 상호작용 구조모형

채현이(Chai, Hyun-Yi) 한국간호과학회 2021 Journal of Korean Academy of Nursing Vol.51 No.5

Purpose: This study aimed to identify the factors influencing the interaction between mothers and preschool-age children and construct a structural equation model based on the factors identified. Methods: The data were collected from the mothers of children aged three to six years enrolled in kindergartens in Seoul, Gyeonggi, Chungbuk, and Jeonbuk. A total of 328 questionnaires were used for the analysis. Analysis was performed using SPSS 26.0 and AMOS 26.0 programs. Results: The child’s self-regulation (β = .42, p < .001) had the most significant influence on the interaction between mothers and preschool children, followed by the mother’s parenting stress (β = - .23, p = .008), social support (β = .17, p < .001), and the child’s active temperament (β = .15, p < .001). The child’s gender, emotional temperament, social temperament, and mother’s education level had indirect influences. Conclusion: These results suggest that interventions considering the child’s temperament, mother’s parenting stress, and social support are required to promote the interaction between preschool- age children and mothers.

Gretchen 비극(悲劇)의 의의(意義)

이명재 한국독어독문학회 1969 獨逸文學 Vol.8 No.1

Chlorella의 生理에 미치는 Ethrel의 효과

蔡麟基,李英玉 梨花女子大學校 韓國生活科學硏究院 1977 韓國生活科學硏究院 論叢 Vol.18 No.-

Ethrel의 Chlorella의 생리에 미치는 영향을 살펴보기 위하여 Ethrel 농도에 따른 Chlorella의 생장, chlorophyll 형성, 광합성 및 호흡시능 그리고 체물질 함량의 변화를 조사하여 보았다. Ethrel 0.1 ppm 농도에서는 Chlorella의 생장이 촉진되었고 고농도의 Ethrel 처리구(1 ppm이상)에서는 억제되었다. 생장을 촉진하는 0.1 ppm 농도에서는 chlorophyll합성과 광합성 및 호흡이 촉진되었고, 탄수화물, 단백질, RNA 등의 함량도 증가되었다. 생장을 억제하는 300 ppm 농도에서는 모든 사항이 생장 촉진농도에서와는 반대의 결과를 나타내었다. DNA 함량은 생장의 촉진이나 억제농도를 막론하고 별 변동이 없었다. The purpose of this research was to define the physiological effect of ethrel on the Chlorella cells by determining the contents of chlorophyll, the photosynthetic and re-spiratory activity, as well as changes in various component material according to the concentration of treated ethrel. The growth of Chlorella was accelerated in low concentration of ethrel (0.1 ppm) and was restrained in high concentrations of ethrel (1, 10, 100, 300 ppm).

Beta-spectra for the Radionuclides in Medicine

Yi, Chul-Young,Kim, Kyung-Hwa,Park, Kyung-Bae,Han, Hyon-Soo,Jun, Jae-Shik,Chai, Ha-Seok Korean Society of Medical Physics 1998 의학물리 Vol.9 No.1

Beta-particle energy distributions of the radionuclides in medicine are calculated for the medical physics applications. The radial component solutions of Dirac wave equations are evaluated for a point-nucleus un screened Coulomb potential. The WKB method is employed to correct the screening due to the orbital-electron cloud. Fierz interference terms are ignored. The radionuclides considered are $\^$32/P, $\^$90/Y, $\^$131/I, $\^$166/Ho, $\^$192/Ir, $\^$198/Au, $\^$153/Sm, $\^$169/Er and $\^$188/Re. A total of 9 beta-spectra for the radionuclides, currently in domestic use or potential use in the near future, are calculated with enough accuracy and presented in graphs and tables.

알칼리 연료전지용 라니니켈 수소극에 미치는 PTFE 의 영향

이성철,김영채,이상곤,문세기,조장호 한국화학공학회 1998 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.36 No.6

퇴원에 따른 만성 질환아 어머니의 반응과 환아 돌보기 지지 요구

채현이,Chai, Hyun-Yi 한국가정간호학회 2001 가정간호학회지 Vol.8 No.1

With the improvement of current medicine, the number of the chronicly ill children are increasing. The illness of the child drives all of the family to despair. especially it is a burden on the mother who takes care of the ill child. She's faced with many emergencies and feels powerless. The home care for a child is for finding a child's problems early and mediating them. The purpose of this study was to investigate the mother's reaction following their chronicly ill child's discharge and to investigate the supporting needs for caring for an ill child. The subjects of this study were mothers with a chronicly ill child being discharged from a general hospital in Seoul and the data was collected from July 20 to September 30. Data was collected by using questionnaires which were developed by the researcher. (The questionnaires were composed of the average 5 points - Likert's method). The Mother's reaction means that the higher the score, the more negative the mother's thoughts about discharge are. Supporting need for caring for ill an child means that the higher the score, the higher the demand of nursing is. The statistical analysis used the SPSS program for t-test. ANOVA, and Pearson Correlation. The results of this study were as follows: 1. The mother's reaction scores following discharge were the lowest. 19 and the highest 72 so that the total average was 43.15. The answer, 'I worry that my baby will be troubled with illness again after discharge gained the high points (3.94 of 5 points). The answer. 'The discharge of my baby makes me gloomy' gained 2.05-it was the lowest points. Their were significant differences according to religion (p=.006). salary (p=.050). the burden of the medical fee (p = .005) and caregiver (p=.027). 2. Supporting Need for caring for ill an child was the lowest 15 and the highest 67. the total average was 47.87. The answer. 'I'd be glad to get a person whom I could always get counsel about the health of my baby with' scored the high point (average 4.04 of 5). The answer. 'Caring for my baby at home makes me exhausted' gained the lowest point. 2.49. Their were significant differences according to religion (p=.019) and diagnosis (p=.019). 3. The relationship between the reaction of the mother and supporting need for caring for an ill child was a positive correlation (r=0.585). In conclusion. this study revealed that mothers weren't positive about their chronicly ill child's discharge and they wanted to get support for caring for an ill child. Through this study. I proposed that the program to support the chronicly ill child at home and home care by continuous counselling after discharge should be develop.

Microstructural and Textural Differences Induced by Water and Furnace Cooling in Commercially Pure Zr Annealed in the α + β Region

Linjiang Chai,Tingting Wang,Yi Ren,Bo Song,Ning Guo,Liangyu Chen 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.4

In this work, a commercially pure Zr sheet with a typical bimodal basal texture was annealed in an α + β region and thensubjected to Different coolings (in water and furnace). Microstructures and textures of both the as-received and the heat-treatedspecimens were investigated by electron channeling contrast imaging and electron backscatter diff raction techniques. Resultsshow that a duplex microstructure consisting of untransformed bulk α grains and twinned martensitic plates is produced inthe water-cooled specimen, which possesses a weakened texture compared to the initial one. For the specimen cooled in furnace,however, a uniform microstructure fully comprised of coarser equiaxed grains with a strengthened texture is obtained. Analyses reveal that the rapid cooling in water could suppress variant selection behaviors during β → α transformation andallow α plates with scattered orientations to be nucleated inside β phases, contributing to the weakened texture. In contrast,during slow cooling in furnace, β boundaries would act as preferred nucleation sites of α embryos, resulting in a strong variantselection that accounts for the intensifi ed texture.

Arsenic Toxicity on Duck Spermatozoa and the Ameliorating Effect of L-Ascorbic Acid

Lin, Chai-Ching,Huang, Chia-Cherng,Chen, Ming-Cheng,Huang, Andrew Jeng-Fang,Chiou, Hung-Yi Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.1

The objectives of this study were to understand the possible mechanism of duck sperm toxicity induced by arsenic exposure in vivo, and to investigate the roles of the antioxidant L-ascorbic acid in ameliorating the arsenic-induced sperm impairment. To test the acute toxicity, the percentages of mortality of mature drakes treated with different concentrations of trivalent sodium arsenite, As (III), and pentavalent sodium arsenate, As (V) were measured. The LD50 value of As (III) for mature drakes was $4.89{\pm}1.49$ ppm. Although As (V) didn't cause any deaths even at a concentration of 40 ppm, the chronic toxicity of As (V) on sperm quality was shown by a decreased fertilization rate. When the concentrations of As (V) were above 0.4 ppm, fertilization rates were lower than those of 0.04 ppm and control. Drakes treated with 40 ppm of As (V) had the highest malondialdehyde (MDA) level in the testis tissue, $3.100{\pm}0.218{\mu}mole/g$ testis. This showed that 40 ppm of As (V) significantly induced lipid peroxidation in testis tissue. For the 1.2 ppm As (III) treatment, several significant effects were observed: (1) sperm motility was decreased most dramatically by $52.0{\pm}9.1$% after three days of incubation; (2) fertilization rate of artificially inseminated semen was the lowest, $26.4{\pm}15.4$; (3) the MDA concentration in testis tissue, $7.846{\pm}0.246{\mu}mole/g$ testis, was significantly higher than the others (p<0.05); (4) the sperm number, $1.17{\pm}0.40({\times}10^9)$, was significantly lower than with the 60 ppb and control treatments (p<0.05); (5) a black appearance and soft texture was observed in the testis tissue. The antioxidant L-ascorbic acid administered along with 1.2 ppm As (III) decreased the toxicity of arsenic. The ameliorating effects included: improved sperm motility, increased sperm number and fertilization rate, and decreased MDA concentration in the testis tissue. This study suggests that the toxicity of the trivalent arsenic on sperm quality is partly from free radicals generated by its metabolic pathway, and the antioxidant ascorbic acid ameliorates arsenic-caused sperm impairment.