• Title/Summary/Keyword: low-loss

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Employment Status and Work-Related Difficulties among Family Members of Terminally Ill Patients Compared with the General Population

  • Kim, Seon Young;Chang, Yoon-Jung;Do, Young Rok;Kim, Sam Yong;Park, Sang Yoon;Jeong, Hyun Sik;Kang, Jung Hun;Kim, Si-Yung;Ro, Jung Sil;Lee, Jung Lim;Lee, Woo Jin;Park, Sook Ryun;Yun, Young Ho
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.1
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    • pp.373-379
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    • 2013
  • Background: Although caregiving to patients with terminal illness is known to be a stressful burden to family members, little attention has been focused on work-related problems. We aimed to investigate employment status and work-related difficulties of family caregivers of terminal cancer patients, comparing with the general population. Methods: Using structured questionnaires, we assessed family caregivers of 481 cancer patients determined by physicians to be terminally ill, from 11 university hospitals and the National Cancer Center in Korea. Results: Among 381 family caregivers of terminal cancer patients (response rate, 87.6%), 169 (43.9%) were not working before cancer diagnosis, but currently 233 (63.7%) were not working. Compared with the general population (36.5%), the percentage of not working among the family caregivers was higher (OR=2.39; 95%CI=1.73-3.29). A major reason for not working was to provide assistance to the patients (71.6%). 40.6% of those who continued working and 32.3% of those who not working family members reported extreme fatigue. Caregivers of old age, those who were female, those with a lower household income, and those caring for patients with a low performance status were not working at a more significant rate. Conclusion: Family caregivers of terminal cancer patients suffer job loss and severe work-related difficulties, probably due to caregiving itself and to fatigue. We need to develop supportive programs to overcome the burden of caregivers of the terminally ill.

The Study on the Crystal Growing of Mn-Zn Ferrite Single Crystals by Floating Zone Method (Floating Zone법에 의한 Mn-Zn Ferrite 단결정성장에 관한 연구)

  • 정재우;오근호
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.2 no.1
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    • pp.10-19
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    • 1992
  • Mn - Zn Ferrite has physical properties of the high initial permeability, saturation magnetic flux density, and low loss factor as a representative magnetic material of soft ferrites, in addition the mechanical property is excellent as a single crystal. Therefore it is important electronic components and used for VTR Head. Mn - Zn Ferrite single crystals with the diameter 8mm were grown in atmosphere mixed with $O_2$ and Ar gas by the Floating Zone(FZ) method that impurities can not be incorporated to the crystals because of not-using the crucible to put in the melt, and the sharp temperature gradient results from making a focus at one point utilizing the infrared ray emitted from the halogen lamp as a heat source. During the crystal growing, the highest temperature of melting area was maintained to be $1650^{\circ}C$, growth rate and rotation rate were 10 mm/hr, 20 rpm respectively. The phases and the growth directions of crystals were determined from the analysis of X RD patterns, Laue, TEM diffraction patterns and etch pit shapes were observed by the optical microscope through the chemical etching. The corelation of optimum conditions for acquiring the better crystals was found out with the growth rate, the length and diameter of melt at the interface according to the diameter of feed rod, and the patterns of growing interface also studied.

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The Magnetic Properties of Nanocrystalline Fe73.5Cu1Nb3Si15.5B7 Alloy Powder Cores (Fe73.5Cu1Nb3Si15.5B7나노 결정립 합금 분말 코아의 자기적 특성)

  • Noh, T.H.;Choi, H.Y.;Ahn, S.J.
    • Journal of the Korean Magnetics Society
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    • v.14 no.1
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    • pp.7-12
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    • 2004
  • The annealing-temperature dependence of magnetic properties in compressed powder cores being composed of ball-milled F $e_{73.5}$C $u_1$N $b_3$S $i_{15.5}$ $B_{7}$ alloy powders (size 250∼850${\mu}{\textrm}{m}$) and 5 wt% of ceramic insulators has been investigated. When annealed at 5$50^{\circ}C$ for 1 h and so transformed to $\alpha$-Fe phase nanocrystalline structure with the grain size of 11 nm (electrical resistivity : 110 $\mu$$.$cm), the highest effective permeability of 125 and quality factor of 53 were obtained, and the permeability persisted up to about 500 KHz. Further the core loss measured at the frequency of 50 KHz and the induction amplitude of 0.1 T was very low (230 mW/㎤). However the dc bias characteristics was not satisfactory as compared to that of conventional powder core materials(MPP, Sendust etc.). The inferior dc bias property of F $e_{73.5}$C $u_1$N $b_3$S $i_{15.5}$ $B_{7}$ alloy powder cores was attributed to the fact that the size of powder was too large for obtaining the same permeability with that of conventional materials.

Anatomical Characteristics of Black and White Charcoal Manufactured in Korea (국내산 흑탄과 백탄의 해부학적 특성)

  • Kwon, Sung-Min;Kwon, Gu-Joong;Lee, Sung-Jae;Kim, Nam-Hun
    • Journal of Forest and Environmental Science
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    • v.23 no.1
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    • pp.57-63
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    • 2007
  • Anatomical characteristics of black and white charcoal of Quercus variabilis and Quercus mongolica manufactured by a Korean traditional kiln were investigated by scanning electron microscopy. In both charcoal, the earlywood vessels shrank in tangential direction, whereas the other cells didn't change. However, in the case of latewood vessels, black charcoal did not show tangential direction shrinkage, but white charcoal did. The wood fiber were changed severly in shape due to the excessive shrinkage. Tyloses in early wood vessel were still shown unchanged shape in both charcoals. Cell wall of ray parenchyma was observed and their shapes were severly distorted. Voids between ray parenchyma were observed in white charcoal, which maybe due to high temperature in white charcoal. Moreover, lumen diameters in the uniseriate ray and multiseriate ray were decreased at the high charring temperature. These results showed that the low charcoal yield of the white charcoal compared to the black charcoal was caused by decrease of cell dimensions as well as loss of wood components associated with the carbonization temperature.

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A Study on the Air Vent Valve of the Hydraulic Servo Actuator for Steam Control of Power Plants (발전소의 스팀제어용 유압서보 액추에이터의 공기배출 밸브에 관한 연구)

  • Lee, Yong Bum;Lee, Jong Jik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.6
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    • pp.397-402
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    • 2016
  • To produce adequate electricity in nuclear and thermal power plants, an optimal amount of steam should be supplied to a generator connected to high- and low-pressure steam turbines. A turbine output control device, which is a special steam valve employed to supply or interrupt the steam to the turbine, is operated using a hydraulic servo actuator. In power plants, the performance of servo actuators is degraded by the air generated from the hydraulic system, or causes frequent failures owing to an increase in the wear of the seal. This is due to the seal being burnt as generated heat using the produced compressed air. Some power plants have exhausted air using a fixed orifice, and thus they encounter power loss due to mass flow exhaust. Failures are generated in hydraulic pumps, electric motors, and valves, which are frequently operated. In this study, we perform modeling and analysis of the load-sensing air-exhaust valves, which can be passed through very fine flow under normal use conditions, and exhaust mass flow air at the beginning stage as with existing fixed orifices. Then, we propose a method to prevent failures due to the compressed air, and to ensure the control accuracy of hydraulic servo actuators.

Preliminary Design of the NISS onboard NEXTSat-1

  • Jeong, Woong-Seob;Park, Sung-Joon;Moon, Bongkon;Lee, Dae-Hee;Park, Won-Kee;Lee, Duk-Hang;Ko, Kyeongyeon;Pyo, Jeonghyun;Kim, Il-Joong;Park, Youngsik;Nam, Ukwon;Park, Chan;Im, Myungshin;Lee, Hyung Mok;Lee, Jeong-Eun;Shin, Goo-Hwan;Chae, Jangsoo;Matsumoto, Toshio
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.2
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    • pp.102-102
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    • 2014
  • The NISS (Near-infrared Imaging Spectrometer for Star formation history) onboard NEXTSat-1 is the near-infrared instrument onboard NEXTSat-1 which is being developed by KASI. The main scientific targets are nearby galaxies, galaxy clusters, star-forming regions and low background regions in order to study the cosmic star formation history in local and distant universe. After the Preliminary Design Review, we have fixed major specifications of the NISS. The off-axis optical design with 15cm apertureis optimized to obtain a wide field of view ($2deg.{\times}2deg.$), while minimizing the sensitivity loss. The opto-mechanical structure of the NISS was designed to be safe enough to endure in the launching condition as well as the space environment. The tolerance analysis was performed to cover the wide wavelength range from 0.95 to $3.8{\mu}m$ and to reduce the degradation of optical performance due to thermal variation at the target temperature, 200K. The $1k{\times}1k$ infrared sensor is operated in the dewar at 80K stage. We confirmed that the NISS can be cooled down to below 200K in the nominal orbit through a radiative cooling. Here, we report the preliminary design of the NISS.

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Composition Changes in Cement Matrix of RC Column Exposed to Fire (화재에 노출된 RC기둥 시멘트 매트릭스의 구성성분 변화)

  • Kim, Jung-Joong;Youm, Kwang-Soo
    • Journal of the Korea Concrete Institute
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    • v.26 no.3
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    • pp.369-375
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    • 2014
  • This study examined the changes of microstructural compositions in cement matrix according to the depth from the surface of a reinforced concrete (RC) column exposed to fire. The RC column was exposed to a standard fire for 180 minutes. After the fire test, core samples passing through the column section were obtained. Using the core samples, the remaining fractions of calcium-silicate-hydrates (C-S-H) and calcium hydroxide in cement matrix at the surface, the depth of 40 mm and 80 mm and the center (175 mm) were examined using thermal gravimetric analysis (TGA) and X-ray diffraction analysis (XRDA). Using nuclear magnetic resonance (NMR) technique, the silicate polymerization of C-S-H in cement matrix was also evaluated. The experimental results indicated that the amount of C-S-H loss at the center of column experiencing the transferred fire temperature of $236^{\circ}C$ has been underestimated as the TGA results showed the highest C-S-H contents are located at the depth of 80 mm, where the transferred fire temperature is $419^{\circ}C$. Moreover, the destruction of silicate connections at the center was observed as similar as that at the depth of 40 mm, where the transferred fire temperature was $618^{\circ}C$. This might be attributed to the temperature changes during cooling time after the fire test was neglected. Due to the relatively low thermal conductivity of concrete, the high temperature, which can affect the change of microstructure in cements, will hold longer at the center of the column than other depth.

An Analysis of Comparative Advantage and Intra-Industry Trade in Korean Export Industry in Respect to Korea-U.S. FTA (한·미 FTA 발효 전후 수출산업의 대미국 비교우위 및 산업내무역 분석)

  • Shim, Jae-hee
    • International Commerce and Information Review
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    • v.19 no.4
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    • pp.175-197
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    • 2017
  • As a revision negotiation on the KORUS FTA has become a national pending issue, this study aims to analyze changes in the trade structure of Korean export industry before and after the KORUS FTA. For the analysis, this study used Market Comparative Advantage(MCA) and Intra-industry Trade(IIT) indexes. Results of the analysis are as follows: First, in analyzing the competitive and complementary relationships of export products using the MCA index, it was discovered that Korea has formed an export-oriented complementary relationship with the United States. Second, the results of analysing IIT showed that Korea has made a low-quality vertical IIT with the U.S. in some items while it has usually made a weak IIT with the U.S.. Based on the results above, this study proposes a few policy suggestions in the following areas: Improvement of competitiveness in trade-deficit service sector, achievement of the balance of profit and loss in goods and service sectors through the revision negotiation of the KORUS FTA, enhancement of competitiveness in competitive and comparative disadvantage items, reinforcement of ability to respond to consumption patterns in U.S. market, etc. in export-dominant items, and pursuit of horizontal-vertical division of labor in comparative advantage items and horizontal division of labor in comparative disadvantage items.

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Premenstrual Syndrome and Personality (인생과 월경 전기 증후군과의 상관관계에 관한 연구)

  • 김은주
    • Journal of Korean Academy of Nursing
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    • v.18 no.1
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    • pp.80-93
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    • 1988
  • This study was planned and carried out to investigate the correlation between premenstrual syndrome and personality in order to provide informations basic to the prevention, alleviation, and care for the premenstrual syndrome. Data on premenstrual syndrome were gatherd from October 20 to 25, 1986 by questionnaire modified by the researcher based on Endicott's Premenstrual Assessment Form. Reliability of the instrument was tested by Cronbach's $\alpha$. Data on personality were gathered in March, 1986, by the high school autorities by standardized Personality Inventory Scale developed by Eung Yun Hwang were used. Subjects numbered 457, 95.2% of the first grade students of H. Girls High School located in Seoul. The correlation and difference between personality traits and premenstrual syndrome analysed by Pearson's Correlation Coefficient, and difference between groups were analysed by the t-test. Personality traits influencing premenstrual syndromal categories were analysed by the multiple regression. The results are as follows : I. The five highist categories of premenstrual syndrome among 18 categories revealed to be Social withdrawal, General discomfort, Lability, Fatigue and Hostility / Anger in rank order. II. Personality traits and Premenstrual syndrome ; 1. Tendency of Psychoneuroses(r=0.43, p<.001), psychoses(r=.39, p<.001) and anti-social behaviors (r=0.43, p<.001) revealed to be significantly correlated to premenstrual syndrome. Hypothesis 1 is accepted. 2. Emotional stability(r= -0.38, p<.001), reflectiveness (r= -0.14, p<.01), masculinity (r= -0.10, p<05) and antonomy (r= -0.12, p<.05) revealed significant correlation, While activity, dominance, sociability and achivement revealed no significant correlation. Hypothesis 2 is partially accepted. III. Significant models of personality traits influencing the premenstrual syndromal categories are ; 1. 5 personality traits : tendency of psychoneuroses, emotional stability, dominance, activity and autonomy revealed to influence Low mood / loss of pleasure significantly. ($R^2$=.19) 2. 3 personality traits ; tendency of psychoneuroses, emotional stability and sociability revealed to influence Lability significantly. ($R^2$=.15) 3. 5 personality traits ; tendency of psychoneuroses, activity, emotional stability, sociability and achievement revealed to influence Anxiety significantly.($R^2$=.18) 4. 3 personality traits : tendency of psychoneuroses, emotional stability and sociability revealed to influence Miscellaneous mood / behavior changes significantly.($R^2$=.18) 5. 3 personality traits : tendency of psychoneuroses, psychoses and reflectiveness revealed to influence Hysteroid features significantly.($R^2$=.16) IV. No significant correlation between irregularity of menstruation and premenstrual syndrome was revealed. No significant difference between group of dysmenorrhea and group of non-dysmenorrhea in premenstrual syndrome was revealed.

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NaBH4 Hydrolysis Reaction Using Co-P-B Catalyst Supported on FeCrAlloy (Co-P-B/FeCrAlloy 촉매를 이용한 NaBH4 가수분해 반응)

  • Hwang, Byungchan;Jo, Ara;Sin, Sukjae;Choi, Daeki;Nam, Sukwoo;Park, Kwonpil
    • Korean Chemical Engineering Research
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    • v.51 no.1
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    • pp.35-41
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    • 2013
  • Properties of $NaBH_4$ hydrolysis reaction using Co-P-B/FeCrAlloy catalyst and the catalyst durability were studied. Co-P-B/FeCrAlloy catalyst showed low activation energy such as 25.2 kJ/mol in 5 wt% $NaBH_4$ solution, which was similar that of noble metal catalyst. The activation energy increased as the $NaBH_4$ concentration increased. Formation of gel at high concentration of $NaBH_4$ seriously affected hydrogen evolution rate and the catalyst durability. The catalyst loss decreased as reaction temperature increased due to lower gel formation when the concentration of $NaBH_4$ was over 20 wt%. Considering hydrogen generation rate and durability of catalyst, the catalyst supported with FeCrAlloy heat-treated at $1,000^{\circ}C$ without ultra vibration during dipping and calcination after catalyst dipping was best catalyst. To use catalyst more than three times in 25 wt% $NaBH_4$ solution, it should be reacted at higher temperature than $60^{\circ}C$.