• Bulletin of the Korean Chemical Society
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• 제5권2호
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• pp.73-78
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• 1984

Superplastic alloys generally exhibit a three-stage sigmoidal variation of stress (f) with strain rate (s), the stages being named region 1, 2 and 3 according to the increasing order of stress or strain rate. In the recent years, two different types of papers have been published on the plastic deformation of Zn-22% Al eutectoid in region Ⅰ differing in strain-rate sensitivity m (= dln f/dln s). In this paper, the data of the two groups have been analysed by applying Kim and Ree's theory of superplastic deformation. (1) We obtained the parametric values of $X_{gj}/{\alpha}_{gj}\;and\;{\beta)_{gj}$ (g: grain boundary, j = 1,2 indicating flow units) appearing in Kim and Ree's theory [Eq. (2a)]. (2) It was found that the value of $X_{g^2}/{\alpha}_{g^2}$ is small for the group data with small m, i.e., ${\alpha}_{g^2}$, which is proportional to the size of flow unit g2, is large whereas ${\alpha}_{g^2}$ is small for the groups data with large m, i.e., the size of the flow unit g2 is small. In other words, the two types of behavior occur by the size difference in the flow units. (3) From the ${\beta}_{gj}$ value, which is proportional to the relaxation time of flow unit gj, the ${\Delta}H_{gj}^{\neq}$ for the flow process was calculated, and found that ${\Delta}H_{g^2}^{\neq}$ is large for the group data with small m whereas it is small for the group data with large m. (4) The flow-unit growth was studied, but it was concluded that this effect is not so important for differentiating the two groups. (5) The difference in ${\alpha}_{g^2}$ and in the growth rate of flow units is caused by minute impurities, crystal faults, etc., introduced in the sample preparation.

• Child Health Nursing Research
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• 제5권1호
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• pp.70-83
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• 1999

The birth of a premature infant is distressing for its parents. The parents of a premature infant experience stress according to the infant's physical appearance and behavior, the environment of the neonatal intensive care unit (NICU) , and the alteration in the parental role. Especially, a mother of a premature infant feels distressed even after the discharge of the infant : therefore, she has difficulties in maternal role performance. The main purpose of this study is to identify the effects of the planned infant care information program in order to lower the stress level for mothers of premature infants caused by the birth and hospitalization in NICU of premature infants, to reduce the maternal role strain, and to promote the maternal role performance after the infants' discharge. This study employed two methods of research at the same time : quasi -experimental non-equivalent pre and post test to compare : non-equivalent post test to compare. The total number of subjects was 19 who were assigned to the research program : 12 mothers of premature infants at the NICU at the Ch university hospital and 7 at the NICU at the Y general hospital located in Chounju city. The data were collected for 79 days from August 18 to November 5, 1998. The questionnaire method was applied for the data collection, and the measures used in this study were Parental Stressor Scale : NICU(Miles, 1993), the Maternal Role Strain Measures ( Hobbs, 1968 ; Steffensmeier, 1982) , and Self Confidence Scale (Pharis, 1978). Research procedure is as follows : after preliminary examination, the experimental subjects, the mothers of premature infants at the Nl CU at Ch university hospital were provided with slide films and information developed by the researcher based on existing documents and data. It took two 60-minute sessions a week for two weeks, and the mothers' stress level was measured using the same instrument twice one week and two week after the infants' hospitalization. The stress level of the contrast subjects, the mothers at Y general hospital was measured during the same period. The experimental subjects were provided with booklets on matters that require attention after the infants' discharge and on developmental project, and they were educated to play the maternal role in person for 2-3 hours a week : breast-feeding, burping a baby, and changing diapers. One week after the infants' discharge, the maternal role strain and the maternal role performance were examined in two groups of the subjects. The analysis of collected data was done using descriptive statistics including real numbers, percentages, averages, and standard deviations. Mann-Whitney test ; x² test ; Repeated Measures Analysis of Variance ; ANCOVA Spearman's rho correlation coefficients. The results on this study were as follows. (1) The examination of the same quality showed that there were no differences in the general and obstetrical characters between the two groups. However, in terms of the characters of premature infants. just right after their birth, the infants at the contrast group weighed more than those at the experimental group(U=16.5, p=.02), and the former was in mother's womb longer than the latter(U=15.5, p=.02). (2) The stress level of the mothers provided with the plannned nursing intervention program became lower as time passed compared to the others'(F=16.61, p=.00) Even when the influence of weight at birth and the length of gestation was removed among the premature infants' characters, the mothers' stress levels made a statistical difference 2 weeks after the infants' hospitalization depending on treatment (F=8.00, p=.01) (3) The maternal role strain of the mothers provided with the planned nursing intervention program was lower than the others'(U=2.0, p=.00). Even when the influence of weight at birth and the length of gestation was removed among the premature infants' characters, the maternal role strain levels made a statistical difference 2 weeks after the infants' hospitalization, depending on treatment(F=14.72, p=.00). (4) The maternal role performance level of the mothers provided with the planned nursing program was higher than the others'(U=.0, p=.00). Even when the influence of weight at birth and the length of gestation was removed among the premature infants' characters, the mothers' stress levels made a statistical difference 2 weeks after the infants' hospitalization, depending on treatment(F=8.00, p=.01). (5) The correlation between a mother's stress level 2 weeks after her infant's hospitalization, the maternal role strain and the maternal role performance were compared : the stress and the maternal role strain were statistically irrelevant to each other(r=.33, p=.12) : the stress was found to be in inverse proportion to the maternal role performance(r=-.53, p=.02). The maternal role strain was in inverse proportion to the maternal role performance as well(r=-.50, p=.00). In conclusion, for the mothers provided with the planned nursing intervention program, their stress level was getting lower as time passed during the infants' hospitalization, their maternal role strain reduced when they took care of their infants after their discharge, and their maternal role performance level was high compared to the other mothers. Besides, the lower the stress level of mothers of premature infants was during the infants' hospitalization, the higher the maternal role performance after their discharge was. The lower maternal role strain was, the higher the maternal role performance was as well. These results of the study suggested that the nursing intervention program for the mothers of premature infants developed by the researcher would be effectively applied to nursing practice, and it would be a foundation for the development of this kind of program.

• Asian-Australasian Journal of Animal Sciences
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• 제9권6호
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• pp.727-735
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• 1996

The effects of four factors-two dietary protein levels (12 and 16%), feeding methods(ad libitum and restricted), strains (A and B), and age of hens-on egg quality and laying performance were examined. Use of the 12% dietary protein level resulted in significantly lower (p < 0.05) hen-day egg production, higher feed intake to about 85% of the ad libitum intake decreased mean hen-day production. Significant feeding method-by-age interactions ($F{\times}A$) were obtained for all parameters. Restricted feeding had favorable effects on shell strength and Haugh unit values after 28 and 16 weeks of egg production, respectively. There was significant difference in shell strength between the two strain. Examination of the three-factor interaction among protein levels, feeding method and strain ($P{\times}F{\times}S$) disclosed that the favorable effect of the A strain on shell strength was significant only with the 16% protein-restricted fed group. The other treatment group did show a trend for greater shell strength of the A strain. Mean values for all the parameters examined changed significantly (p < 0.01) with the age of hens. Feed intake per dozen eggs tended to increase, with some fluctuation, as the hens aged. There was a linear decrease in Haugh unit scores and shell strength. The effect of restricted feeding on either shell strength or Haugh unit scores were favorable for the aged chickens.

• 소성∙가공
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• 제7권2호
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• pp.168-176
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• 1998

Hot workability of the AA5083 alloy ws investigated by torsion test at temperature ranges of $350{\sim}520^{\circ}C$ and strain rates of 0.5, 1.0, and 3.0/sec. The flow stress and hot ductility of the AA5083 alloy as a function of deformation variables such as temperature and train rate were studied. The microstructural evolution of the AA5083 alloy was studied in relation to Zener-Hollomon parameter (Z=exp( /RT) Also the hot restoration mechanism of the AA5083 alloy was small when Z val-ues were higher than $1.73{\times}1016/sec(370^{\circ}C,\;0.5/sec)$ In addition the difference microstructures during hot deformation. It was found that the increase of flow curves and deformed microstructures during hot deformation. It was found that the increase of flow stress of the AA5083 alloy was small when Z val-ues were higher than $1.73{\times}1016/sec(370^{\circ}C.\;0.5/sec)$. However under the low Z values less than $1.73{\times}1016/sec(370^{\circ}C,\;0.5/sec)$ the flow stress increase with increasing the Z values. The large dispersoid particles in the matrix grain decreased the flow strain of the AA5083 alloy because it caused the stress concentration during hot deformation.

• Journal of Microbiology
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• 제38권3호
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• pp.160-168
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• 2000

A-factor I a microbial hormone that can positively control cell differentiation leading to spore formation and secondary metabolite formation in Streptomyces griseus. to identify a protease that is deeply involved in the morphological and physiological differentiation of Streptomyces, the proteases produced by Streptomyces griseus IFO 13350 and its A-factor deficient mutant strain, Streptomyces griseus HH1, as well as Streptomyces griseus HH1 transformed with the afsA gene were sturdied. In general Streptomyces griseus showed a higher degree of cell growth and protease activity in proportion to its ability to produce a higher amount of A-factor. In particular, the specific activity of the trypsin of Streptomyces griseus IFO 13350 was greatly enhanced more than twice compared with that of Streptomyces griseus HH1 in the later stage of growth. The specific activity of the metalloprotease of Streptomyces griseus HH1 was greatly enhanced more than twice compared with that of Streptomyces griseus IFO 13350, and this observation was reversed in the presence of thiostreptione, However, Streptomyces griseus HH1 transformed with the afsA gene showed a significantly decreased level of trypsin and metalloprotease activity compared with that of the HH1 strain. There was no significant difference between Streptomyces griseus IFO 13350 and HH1 strain in their chymotrypsin and thiol protease activity, yet the level of leu-amionpeptidase activity was 2 times higher in Streptomyces griseus HH1 than in strain IFO 13350 . Streptomyces griseus HH1 harboring afsA showed a similar level of enzyme activity , however, all the three protease activities sharply increased and the thiol protease activity was critically increased at the end of the fermentation. When a serine protease inhibitor, pefabloc SC, and metalloprotease inhibitor, EDTA, were applied to strain IFO 13350 to examine the in vivo effects of the protease inhibitors on the morpholofical differentiation, the formation of aerial meycelium and spores was delayed by two or three days.

• 한국전산구조공학회논문집
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• 제23권5호
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• pp.551-557
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• 2010

본 연구는 경량콘크리트와 폴리머 개질 경량콘크리트 보에 있어 현행 최소허용철근변형률 기준의 타당성과 최외단 철근의 순인장 변형률에 따른 휨 거동 및 휨 성능을 평가하는 것에 그 목적이 있다. 크기와 형상이 동일한 8개의 시험체를 제작하여 콘크리트의 종류와 최외단 철근의 순인장 변형률을 변수로 실험을 수행하였으며, 이를 통해 순인장 변형률에 따른 경량콘크리트 보와 폴리머 개질 경량콘크리트 보의 강도와 연성의 변화를 분석하였다. 실험 결과 경량콘크리트 보와 폴리머 개질 경량콘크리트 보 모두에서 최외단 철근의 순인장 변형률이 증가할수록 시험체의 연성이 증가하였으며, 특히 최외단 철근의 순인장 변형률 0.005이상에서 보통 중량 콘크리트와 유사한 연성지수를 확보할 수 있었다.

• The Plant Pathology Journal
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• 제36권5호
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• pp.428-439
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• 2020

Erwinia pyrifoliae is a Gram-negative bacterial plant pathogen that causes black shoot blight in apple and pear. Although earlier studies reported the genome comparison of Erwinia species, E. pyrifoliae strains for such analysis were isolated in 1996. In 2014, the strain E. pyrifoliae EpK1/15 was newly isolated in the apple tree showing black shoot blight in South Korea. This study aimed to better understand the similarities and differences caused by natural variations at the genomic level between newly isolated E. pyrifoliae EpK1/15 and the strain Ep1/96, which were isolated almost 20 years apart. Several comparative genomic analyses were conducted, and Clusters of Orthologous Groups of proteins (COG) database was used to classify functional annotation for each strain. E. pyrifoliae EpK1/15 had similarities with the Ep1/96 strain in stress-related genes, Tn3 transposase of insertion sequences, type III secretion systems, and small RNAs. The most remarkable difference to emerge from this comparison was that although the draft genome of E. pyrifoliae EpK1/15 was almost conserved, Epk1/15 strain had at least three sorts of structural variations in functional annotation according to COG database; chromosome inversion, translocation, and duplication. These results indicate that E. pyrifoliae species has gone natural variations within almost 20 years at the genomic level, and we can trace their similarities and differences with comparative genomic analysis.

• Asian-Australasian Journal of Animal Sciences
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• 제8권4호
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• pp.325-328
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• 1995

The experiment was conducted to study the comparative pathology of hemic system among three different broiler chicken strains i.e. Hubbard (H), Lohmann (L) and Indian River (IR) suffering from experimentally induced Hydropericardium Syndrome (HPS). For this 50 chicks of each strain were inoculated with HPS inoculum at the age of 21 days and other 50 chicks of each broiler strain were kept as uninoculated control. After slaughtering each bird of both groups was subjected to pathological examination of heart, spleen and aorta and also for determining routine haematological parameters. The maximum values of Total Erythrocyte Count (TEC), heterophils and thrombocytes and the minimum values of Total Leukocyte Count (TLC) and Hemoglobin (Hb) content were found in H broiler strain. Percentage of monocytes, basophils and eosinophils also showed maximum decrease in H broiler chicken strain. Gross pathological lesions in the inoculated birds revealed that the heart showed ballooning due to distention of pericardial sac with pericardial fluid. Haemorrhages on the epicardium and flabbiness of the myocardium. Under the microscope, degenerative changes in myocardial tissue were seen. Lesions in the spleen included splenomegaly and haemorrhagic spots. Aorta showed flabbiness of the wall and disruption of endothelium. It is concluded that there is a marked difference in susceptibility of HPS among three different commercial broiler strains. The Hubbard broiler strain is more susceptible which is followed by the Indian River and Lohmann respectively.

• 한국수산과학회지
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• 제49권3호
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• pp.351-358
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• 2016

The aim of this study was to verify the performance of Teleaulax amphioxeia as prey for Brachionus plicatilis and for the larvae of the bivalves (Pacific oyster Crassostrea gigas and Manila clam Ruditapes philippinarum) to select the best of five T. amphioxeia strains. The five strains of T. amphioxeia were collected from the coasts of Korea, purecultured and then fed to the rotifer and bivalve larvae. The density and fecundity rate of the rotifer fed on strain 01 were the highest. The instantaneous growth rate of the rotifer fed strain 08-2 was the highest. The maximum density and fecundity rate of the rotifer fed strain 08-2 were significantly higher than those fed Chlorella ellipsoidea, while instantaneous growth rate showed the opposite pattern. Survival rates of the Manila clam larvae fed each strain of Teleaulax showed no significant difference between strains. Survival rates of the Pacific oyster fed Teleaulax were significantly higher than those fed Chaetoceros sp., but lower than those fed I. galbana. This study indicates that strain 08-2 showed better growth for B. plicatilis and better survival for the bivalve larvae than did the other strains, and that T. amphioxeia can also be used as a prey organism for rotifers or bivalve larvae.

• 대한수의학회지
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• 제2권1호
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• pp.51-54
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• 1962

Chang et al. 및 Glick 등은 어린 닭에있어 Fabricius' Bursa가 면역항체형성(免疫抗體形成)에 영향(影響)를 미치는것을 관찰보고(觀察報告)한바있다. 즉(卽) S.typhimurium antigen 또는 양적혈구(羊赤血球)를 주사(注射)하였을경우 Fabricius' Bursa를 적출(摘出)한 어린 닭에 있어서는 면역항체형성(免疫抗體形成)의 감소(減少)를 보았다고 하며 또한 Bursectany를 한 닭에 있어서는 S.typhimurium 주사(注射)로 인(因)한 폐사율(斃死率)이 보다 높았다고 한다. 이러한 Fabricius' Bursa의 영향(影響)은 부화후(孵化後) 처음 몇주(週)에 있어 가장 현저(顯著)하며 닭의 성장(成長)과 덥으로 점차 감소(減少)됨을 보고(報告)하고 있다. 그러나 이들의 연구(硏究)에는 그의 본질(本質)이 같은 세포성(細胞性)인 항원(抗原)만이 사용(使用)되었을 뿐만 아니라 그의 접종방법(接種方法)도 근육내(筋肉內) 및 정맥내(靜脈內)의 두 방법(方法)에 한(限)하였다. 면역항체(免疫抗體)를 형성(形成)하는 여러 기관조직(器官組織)의 항체형성(抗體形成)에의 비율적관여(比率的關與)는 항원(抗原)의 본질(本質) 그의 접종방법(接種方法)등에 따라 다르므로 여기에 필자(筆者)들은 Virus 항원(抗原)인 Newcastle Virus ($B_1$ strain)를 경비적(經鼻的)으로 접종(接種)하였을 경우의 Fabricius' Bursa의 항체(抗體) 형성(形成)에 미치는 영향(影響)을 연구(硏究)하였다. 부화후(孵化後) 3주(週)되는 Leghorn종(種)의 어린 닭의 Fabricius' Bursa를 적출(摘出)하고 1주일후(週日後)에 Newcastle Virus ($B_1$ strain)를 경비적(經鼻的)으로 접종(接種)하였던 바 HI반응(反應)에 의(依)한 그의 혈청역가(血淸力價)(serum titer)는 정상(v)Control group의 그것에 비(比)하여 통계학적(統計學的)으로 의의(意義)있는 차(差)가 없음을(P>0.1) 보았다.