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The Magnetic and Microwave Absorbing Characteristics of Ni-Zn Ferrite Composites (니켈-아연 페라이트복합재의 자기적특성과 전파흡수특성)

  • 조성백;오재희
    • Journal of the Korean Magnetics Society
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    • v.3 no.2
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    • pp.115-120
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    • 1993
  • The relationship between magnetic parameter and microwave absorbing performance evaluation factor of electomagnetic wave absorber such as matching frequency, matching thickness were investigated for Ni-Zn ferrite composites. It was identified that the maximum value of ${\mu}_{r}$" is shift to low frequency with decrese Ni/Zn ratio and the value of ${\mu}_{r}$" is maximum in the case of Ni/Zn=1. All Ni-Zn ferrite composites in this study have two matching frequencies in 1-12 GHz frequency. It can be suggested that $f_{m1}$ is proportional to resonance frequency and $f_{m2}$ is proportional to the saturation magnetization.

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An Experimental Study on the Characteristics of Spray Pattern and the Mixing Performance of Unlike-impinging Split Triplet Injector(F-O-O-F) (F-O-O-F 충돌형 injector의 분무특성 및 혼합성능에 관한 실험적 연구)

  • Lee, K.J.;Moon, D.Y.;Kim, Y.
    • Journal of the Korean Society of Propulsion Engineers
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    • v.3 no.3
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    • pp.1-8
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    • 1999
  • Mixing efficiency of the unlike Impinging split triplet injector(FOOF type) were measured to investigate the effect of the momentum ratio variation. $H_2$O/kerosene were used as a propellant simulant. The maximum mixing efficiency occured at the momentum ratio 1.5 (total mixture ratio 1.89). Calculated mixing efficiency of real propellant LOX/Kerosene showed similar trend but maximum efficiency of characteristic velocity occurs at the momentum ratio 2.0(total mixture ratio 2.17). Although there exist a little discrepancy between calculated mixing efficiency based on simulant cold test and hot fire test results, this calculated mixing efficiency can be used to predict hot fire mixing efficiency.

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Thermal Stress Anaysis of Burning Plate by Configuration of Outdoor Gas Boiler (야외용 가스보일러의 연소판 형상에 따른 열응력 해석)

  • Lee, Suk Young
    • Journal of Energy Engineering
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    • v.24 no.4
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    • pp.48-54
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    • 2015
  • This study investigates the result of thermal stress analysis on burning plate by classes at outdoor gas boiler. In the analysis results at the steady state, the maximum stress and deformations are 666,8MPa at A type and 0.20476mm at B type respectively. The deformation becomes larger as the field goes on from the center to the outside at burning plate. As there are 8 types in the order of maximum stress and deformation, F and C type have safest among 8 types respectively. Therefore, F type becomes most excellent on strength and safety among 8 types. By using the analysis result of burning plate model at gas boiler, it is possible to design the model applied practically at the safe component parameters of boiler system.

Numerical study on flow characteristics at dividing open-channel with changing bifurcation angle using TELEMAC-2D (TELEMAC-2D모형을 이용한 분류각 변화에 따른 개수로 흐름특성변화 수치모의 연구)

  • Jung, Daejin;Jang, Chang-Lae;Jung, Kwansue
    • Journal of Korea Water Resources Association
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    • v.53 no.8
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    • pp.617-626
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    • 2020
  • This study investigates changes of bifurcation discharge ratio, flow velocity distributions and characteristics of separation zone due to variation of bifurcation angle by using TELEMAC-2D model. When the bifurcation angle is reduced from 90° to 45° without changing the boundary conditions, the bifurcation discharge ratio increased by 1.5 times from 0.523 to 0.785 because of increasing the radius of curvatures, the inertia force of the downstream flow, and the pressure gradient by the downstream boundary conditions. The bifurcation discharge ratio increases non-linearly whenever the bifurcation angle decreases by 15° intervals from 90° to 45° in flow with the upstream Froude number of 0.45 to 0.74. In flow with a maximum Froude number of 0.74, the rate of increase for bifurcation discharge ratio is 31.1% and the minimum value. When the Froude number is 0.58, the bifurcation discharge ratio is 0.7 or less, and the maximum rate of increase for that ratio is 53.5%. As the upstream Froude number decreases less than 0.58, the bifurcation discharge ratio exceeds 0.7, and the rate of increase decreases. When the upstream Froude number is 0.4 higher, the dimensionless width and length changing ratio of the separation zone are about 2.56 and 5.5 times higher than in 0.4 or less.

A Study of the Quality of Life of the Cancer Patients Undergoing a Radiation Therapy (방사선 요법을 받는 암환자의 삶의 질에 관한 연구)

  • Jang Keum-Seong;Noh Young Hee
    • The Journal of Korean Society for Radiation Therapy
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    • v.6 no.1
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    • pp.154-170
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    • 1994
  • The Purpose of this study was to determine the degree and contents composing the qualify of life and to analyze the relationships among the demographic characteristics, the degree of pain and the quality of life of the cancer patients experiencing a radiation therapy. The subjects for this study were 110 out-patients experiencing a radation therapy at C University Hospital in K-city, from April to October, 1992. The data were obtained using a convenience sampling technique. The tool of this study was the quality of life scale developed by Ro, You-Ja and the data were analyzed using a SAS program for percentages, mean & standard deviation. ANOVA and Scheffe test. The results were as follows : 1. the average total score of the quality of life of the subjects was 139.65(minimum score 121-maximum score 164), item mean score grange 1-5) was 2.97. For each factor in the quality of life scale, the mean scores (range 1-5) were 3.29 in emotional state, 3.14 in relationship with neighbors. 3.04 in physical state and function. 2.92 in self-esteem, 2.81 in economic life and 2.65 in relationship with family. 2. The incidence of physical symptoms was seen fatigue ($84.5\%$). anorexia ($65.5\%$) and weight loss ($47.3\%$) in order. The 50.9 percentage of the subjects complained of moderate or severe pain. 3. The results of the analysis of the relationships between the demographic variables and the quality of life were as follows : Gender (F=8.45, P=0.0044), age (F=6.29, P=0.0001). educational level (F=5.67, P=0.0046), marital status (F=6.82. P=0.0016), occupation (F=2.86, P=0.009), monthly income (F=6.90, P=0.0003), family living together (F=3.95, P=0.0494) and person paying a medical fee (F=5.14, P=0.0023). 4. The relationship between the degree of pain and the quality of life was significant difference (F=3.12, P=0.0482).

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A Study of the Relationship between Self Concept and Depression of Middle-Aged Women (중년여성의 자아개념과 우울에 관한 연구)

  • Kim, Jung-Youb
    • Women's Health Nursing
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    • v.3 no.2
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    • pp.113-128
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    • 1997
  • The purpose of this study was to investigate the relation between self concept and depression of middle-age women. Data were collected by a questionnaire from June 23 to July 3, 1997. The subject for this study were 138 women between 40-60 years of age living in Seoul and Incheon. The instruments used for this study were the self concept scale developed by Rosenberg and Choi, Jung-Hun and the depression scale developed by Rockliff and the investigator. The data were analyzed by descriptive statistics, t-test, ANOVA, Pearson correlation coefficient, stepwise multiple regression using the SPSS program. The results of this study were as follows 1. Mean score of self concept was 3.58, in minimum score 2.86 to maximum score 3.99. 2. Mean score of depression scale was 1.95, in a minimum score 1.50 to maximum score 2.61. 3. The relationship between self concept and depression was statistically significant negative correlation(r=-0.5121, p<0.001). 4. General characteristics variables significantly related to the level of self concept were marital status(t=-3.22, p<0.01), experience of disease in a year(t=2.76, p<0.01), child problem(t=-2.59, p<0.05), marital satisfaction(F=6.80, p<0.05). 5. General characteristics variables significantly related to the level of depression were possession of house(t=-2.42, p<0.01), experience of disease in a year(t=-4.32, p<0.001), child problem(t=3.12, p<0.05), husband problem(t=5.29, p<0.001), marital satisfaction (F=8.36, p<0.001). 6. Obstetrical characteristics variables significantly related to the level of self concept was times of pregnancy(F=3.54, p<0.05). 7. Obstetrical characteristics variables significantly related to the level of depression were age of menarche(F=3.87, p<0.05), times of abortion(F=2.49, p<0.01) number of children(F=3.36, p<0.01). 8. In the stepwise multiple regression analysis, the main influencing variables on depression of middle aged women were self concept($R^2$=.26, p<0.001), husband problem ($R^2$=.37, p<0.001), experience of disease in a year($R^2$=.41, p<0.001) and possession of house($R^2$=.44, p<0.001).

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Electrical Properties of (Ba,Ca)(Ti,Zr)O3 Ceramics for Bimorph-type Piezoelectric Actuator

  • Shin, Sang-Hoon;Yoo, Ju-Hyun
    • Transactions on Electrical and Electronic Materials
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    • v.15 no.4
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    • pp.226-229
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    • 2014
  • In this study, lead-free $(Ba_{0.85}Ca_{0.15})(Ti_{1-x}Zr_x)O_3$ ceramics and a bimorph-type piezoelectric actuator were fabricated using the normal oxide-mixed sintering method, and their dielectric properties, microstructure, and displacement properties were investigated. From the results of X-ray diffraction, the pattern of the specimen has a pure perovskite structure. In addition, no secondary impurity phases were found. The excellent piezoelectric coefficient of $d_{33}=454pC/N$, the electromechanical coupling factor $k_p=0.51$, the dielectric constant ${\varepsilon}_r=3,657$, the mechanical quality factor $Q_m=239$, and $T_c$(Tetragonal-Cubic) =$90^{\circ}C$ were shown at x= 0.085. ${\Delta}k_p/k_p20^{\circ}C$ and ${\Delta}f_r/f_r20^{\circ}C$ showed the maximum value of -0.255 and 0.111 at $-20^{\circ}C$ and $80^{\circ}C$, respectively. The maximum total-displacement was $60{\mu}m$ under the input voltage of 50 V. As a result, it is considered that lead-free $(Ba_{0.85}Ca_{0.15})(Ti_{1-x}Zr_x)O_3$ ceramics is a promising candidate for piezoelectric actuator application for x= 0.085.

A Study on the Decisive Factors in Personal Health Maintenance Practice of Housewives Living in Younhi Area Apartments (연희지역 아파트주부의 건강관리실천의 결정요인분석에 관한 조사연구)

  • 김인숙
    • Journal of Korean Academy of Nursing
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    • v.8 no.2
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    • pp.89-102
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    • 1978
  • Owing to the development of modern science, prolonging man's life, the sudden increase of population and betterment of the standard of living has increased health needs. In order to fulfill these health needs, more active plans for developing health should be made. Health education is one of the methods at hand that can improve the health behavior of the community and the individual through the contact of individuals with their groups. Proper understanding of the characteristics of the sampled group and participation of individuals within the community for the development of their health plan are needed for efficient health education. This study was attempted for the purpose of presenting some data helpful for pre-paring the fundamentals of a health education plan that can improve personal health maintenance practice of a community through efficient health education by investigating the relationship between the response of subjects to personal health maintenance practice and selected decisive factors in personal health maintenance practice. The subjects for this study were a systematic sample of 120 housewives selected from 600 housewives from B Zone Apt. Younhi-3-Dong in Seoul. Data was collected for 4 days from May 16th to May 19th, 1578 through personal interviews with questionnaires by well trained interviewers. Percentage, t-test and stepwise multiple regression analysis by use of EDPS were employed for statistical analysis. Results of this study can be summarized : 1. General characteristics of subjects Subjects over 20 and below 40 years of age formed 62.5% of the toed and the rest were subjects of 40 years and upward. 76.7% of the subjects have less than 4 children. 51.3% of the subjects had completed at least the senior high school course. 2. The response of subjects to personal health maintenance practice. Ratios of personal health maintenance practice to the maximum score for each category are as follows; 84.1% in the category of population and family planning, which was the highest ratio; 82.4% in the prevention of accidents; 68.0% in control of communicable disease; 67.8% in personal health care and habits of daily life, 64.3% in mental health and 52.5% in control of parasites, which was the lowest. 3. The response of subjects to selected decisive factors. in personal health maintenance practice. The arithmetic mean of the score for each decisive factor was as follows: the mutual relation between family members marked 18.33, which is under 73,3% of the maximum score; the degree of interest in health marked 34.48, 70.0% of the maximum score: the degree of utilization and demand for health care facilities marked 25.79 or 64.5% of the maximum score and health maintenance of the family marked 11.58, 43.6% of the maximum score. 4. The relationship between personal health maintenance practice and general characteristics of subjects. 1) There was a significant difference in the numbers of children. (t = 1.83, d.f. =117, p< 0.1) 2) There was a significant difference in the contact rates with mass-media, (t = 5.02, d.f. = 118, p< 0,05) 5. The multiple correlation between personal health maintenance practice and their selected decisive factors. 1) The factor“the degree of interest in health”could account for personal health maintenance practice in 43.6% of the sample. (R = 0.6602, R²= 0,4359, F = 91.1678, p< 0.001) 2) When the factor,“health maintenance of family”is added to this, it accounts for 51.2% of personal health maintenance practice. (R = 0.7158, R²= 0.5124, F = 61.4653, p< 0.001) 3) When the factor,“mutual relations between family members”is also included, it accounts for 53.7% of personal health maintenance practice. (R = 0.7324, R²= 0.5365, F = 44.7509, p< 0.001) 4) When the factor, “the degree of utilization and demand for health care facilities”is included, it accounts for 55.1% of personal health maintenance practice. (R = 0.7421, R²= 0.5507, F = 35.2430, p< 0.001).

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A Study of Ethical Sense of Value and Discord of the Clinical Nurse (임상간호사(臨床看護師)의 윤리적(倫理的) 가치관(價値觀)과 윤리적(倫理的) 갈등(葛藤)에 관한 연구(硏究))

  • Jong, Heui-Ja;Moon, Heui-Ja
    • Journal of Korean Academy of Nursing Administration
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    • v.1 no.2
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    • pp.349-371
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    • 1995
  • Professional nurse shall possess the firm nursing idea and ethical nursing philosophy based on the professional knowledge and technology but due to the rapid social situations has changed the value to man thus the nurse's sense of value in the nursing secenes has been confused and changed bringing the new ethical problems and discord due to the ethically difficult problems. This study is aimed to know about the discord between the ruling ethical sense of value and the ethical discord exeriencing in the clinical scenes of the nurse and to help them establish affirmative ethical sense of value and provide them with the materials which can effectively meet the ethical discord. The study research has been conducted by selecting 515 clinical nurses in 8 general hospitals as the subject from Mar. 13, 1995 to Apr. 3. The tool measuring the ethical sense of value disigned by Lee, Young Sook has been used and supplemented and the tool measuring the ethical discord was the question papers about the ethical dillemma of Han, Sung Sook. The collected materials have been analyzed by the statistical methods of arithmetical everage, t-test, ANOVA, Pearson's Correlation Coefficient and etc. The result of the study is as the below ; 1) The average point of the ethical sense of value of the nurse was 3.62(maximum point : 5) which showed that the ethical level was so high and the highest question item in the ethical level of the whole items of the ethical sense of value was "They conduct as directed by the doctor in case the disposition of the doctor looks mistaken"(4.56 point), "They keep the secret of the patients while serving them."(4.56) and the lowest item was "using placobo for the patients is not allowed" : (1.85 point). 2) Statistical variation which showed the significant difference in the relation with the ethical sense of value according to the general characters of the nurse has shown as scholarly years(F=3.47, p=.016), religion(F=1.66, p=.004), interest degree of ethical education(F=4.18, p=.006),attitude to the job of nursing(F=6.76, p=.006), ethical standard(F=3.28, p=.021), and recognition degree on ethical principles(F=4.53, p=.001). 3) The average point of the ethical discord of the nurse was 0.54(The maximum-1 point) point and the ethical discord in the clinical scenes : "the problems arising from the lack of manpower of the nurse"(0.86), "the discord from the uncooperative relation between them and the medical staff and"(0.75) and indifference of the doctor about the report of the nurse(0.73). 4) The variation which showed the significant difference statistically in the ethical discord according to the general characters of the nurse was that Age(F=19.88, p=.000), schooling(F=5.32, p=.001), Experience(F=15.77, p=.000), position(F=13.58, p=.000) and ethical standard(F=2.63, p=.049). 5) The results of the analysis of correlation between ethical sense of value and discord(r=0.519, p=.239) showed no significant correlation statistically.

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Effect of Genotype and Dietary Protein Level on Growth Performance and Carcass Characteristics of Fattening Pigs in Central Vietnam

  • Pham, Khanh Tu;Hoang, Nghia Duyet;Le Duc, Ngoan;Hendriks, W.H.;Van Der Peet-Schwering, C.M.C.;Verstegen, M.W.A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.23 no.8
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    • pp.1034-1042
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    • 2010
  • This study aimed to determine the optimum dietary crude protein level in a typical diet for fattening pigs fed ad libitum under normal climate conditions in Central Vietnam. One hundred and ninety two gilts of Mong Cai local breed (MC), $F_1$ Large White${\times}$Mong Cai and $F_2$ crossbreds of (Landrace${\times}$Mong Cai)${\times}$Large White were used. At the start of the experiment, Mong Cai pigs weighed 12 kg at 11 weeks of age, $F_1$ pigs 12.1 kg at 8 weeks of age and $F_2$ pigs 12.2 kg at 8 weeks of age. Four diets differing in crude protein (CP) content (10.1, 13.1, 16.1 and 18.9% in DM) were formulated from rice bran, corn meal, cassava meal and fish meal. Calculated digestible energy content of the diets ranged from 13.5 to 13.8 MJ per kg DM. Pigs were housed individually in pens of $2.5\;m^2$ each and had ad libitum access to feed in a trough as well as water in bowls. The final weights after a growing period of 150 days were 66, 86 and 96 kg for MC, $F_1$ and $F_2$, respectively. Feed intake of MC pigs was highest at 13.1% CP while $F_1$ and $F_2$ had the highest feed intake at 16.1% CP. The results showed that for MC the maximum gain was obtained at levels between 13 to 16% CP. For the $F_1$ the maximum gain was at dietary protein levels of 16-17%. For $F_2$ the max gain was obtained at CP levels of 16 to 18%. Feed conversion was highest in MC pigs (~4.0) followed by $F_1$ (~3.3) and $F_2$ (~3.1), and within genotypes was lowest at the optimum CP level (p<0.05). Back fat thickness in MC (33.1 mm), $F_1$ (23.0 mm) and $F_2$ (20.5 mm) pigs was different and within genotypes was the lowest at intermediate CP levels. In conclusion, increasing the dietary crude protein contents in practical diets for pigs in Vietnam can increase production on small holder farms. Optimal performance for MC, $F_1$ and $F_2$ pigs is achieved at different dietary crude protein contents.