• Earthquakes and Structures
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• 제2권1호
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• pp.1-24
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• 2011

During very strong earthquakes, seismically isolated buildings may experience large horizontal relative displacements, which may lead to poundings if an insufficiently wide clearance is provided around the building. This paper investigates, through numerical simulations, the effectiveness of using rubber bumpers, which could be attached at locations where it is likely to have impacts, in order to act as shock-absorbers. For the simulation of the dynamic behavior of such rubber bumpers during impacts, a nonlinear force-based impact model, which takes into account the finite thickness of the rubber bumpers, has been developed. Subsequently, a series of parametric analyses are performed to assess the effect of the gap size, the earthquake characteristics and the thickness, compressive capacity and damping of the bumpers. The stiffness of the moat wall is also parametrically considered during poundings of a seismically isolated building, as another potential mitigation measure for poundings of seismically isolated buildings.

• Journal of Mechanical Science and Technology
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• 제18권1호
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• pp.20-29
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• 2004

This paper proposes a new type of bearing system. In this study, a method for design of on elastomeric bearing system and its mechanical property analysis are carried. Experimental and theoretical studies of the elastomeric bearings with fiber reinforcement were proved effective new lightweight bearing system. The fibers in the bearings for isolation are assumed to be flexible in extension, in contrast to the steel plates in the conventional bearing system. Several kinds of bearing systems in the form of long strips are designed, fabricated and tested. The results suggest that it is possible to produce the economical and effective fiber-reinforced elastomeric bearing that matches the behavior of a steel-reinforced bearing. Feasibility and advantages of the proposed bearings are illustrated by the application of the analytic procedure to the structure system. Results obtained here are reported to be an efficient approach with respect to bearing system and design of bearing against shock absorbing system when compared with other conventional one.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1-4
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• 2005

This paper describes work on isolation of vibration related engine by a hydraulic engine mount with controllable area of inertia track. Automotive engine mounts are required to constrain motion of engine shake resulting from low-frequency road input of shock excitation and also to isolate noise and vibration generated by the engine with unbalanced disturbance at the high frequency range. The property of the mount depends on vibration amplitude and excitation frequency, which means that the excitation amplitude is large in low excitation frequency range and small in high frequency range. In this paper, theoretical works with model of the mount to reduce vibrations related engine were conducted. The volumetric stiffness of the mount is greatly changed according to the switching the area of the inertia track. Therefore, when the area of the inertia track is tuned, the transmissibility of the mount is effectively reduced.

• 대한기계학회논문집
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• 제8권4호
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• pp.335-342
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• 1984

본 연구에서는 무부하상태의 기관회전에 따른 차체진동특성을 해석하기 위한 모델로서 차체질량계를-선형적 특성을 갖는 스프링 및 함쇠기(shock absorber)로 연결 된-기관계와 현가질량계로 분리하고 국내상샌의 승용차를 대상으로 하여 10자유속계의 동력학적 모델을 구성한다.

• 대한간호학회지
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• 제27권2호
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• pp.444-453
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• 1997

The purpose of this study was to construct a grounded theory as the basis for nursing intervention by describing and analysing the holistic lived experiences of clients receiving long-term hemodialysis. The subjects of this study were fifteen persons receiving regular hemodialysis regimen at artificial kindey treatment centers in two different university hospitals, and who were able to participate in conversation and were available for long and dup interviews. Eight of the subjects were male and seven were female and their ages ranged from 30's to 60's. The length of the hemodialysis experience ranged from two months to six years. The collection and analysis of data were done in accordance with the grounded theory methodology of Strauss & Corbin. The method to collect the data mainly depended. on long and deep interviews, participant observation and focused group interviews and the equipment used to collect data were a portable tape recorder and field notes. The study is summarized as follows : 1. The meaning of holistic lived experiences of clients receiving long -term hemodialysis was found to be uncertainty. which was identified as the core category. 2. The main categories following the core category were found to be shock, ambiguity, social support and quality of life. 3. Through the main category the type of behavior newly formed by clients receiving long-term hemodialysis was found to be as follows. That is to say, in the circumstances of shock caused by the identified fact and the ambiguity of hemodilysis they formed a quality of life based on social support, which was found to be a kind of chaotic phenomenon. 4. The lived experiences of clients receiving long-tern hemodialysis was found to include nine categories : emotional shock, feelings of isolation, burden, unclearness, dependency, help from others, coping strategies, maintenance of self-esteem and transitional life. 5. The intervening factors influencing each category are as follows : 1) The factors influencing 'emetional shock' were found to be set age, the level of knowledge received in advance, locus of control, the period of struggle against the disease before hemodialysis and whether any serious illness existed. 2) The factors influencing 'feelings of isolation' were found to be religion and the length of the hemodialysis experience. 3) The factors influencing 'burden' were found to be sex, economic situation, employment status and the length of the hemodialysis experience. 4) The factors influencing 'unclearness' were found to be sex, age, religion. economic situation, the length of the hemodiaysis experience, whether they had had a transfusion and whether there were any complications. 5) The factors influencing 'help from others' were found to be religion. economic situation, past experiences and whether family members lived together. 6) The factors influencing 'coping strategies' were foung to be age, level of education, experiences of illness and locus of control. 7) The factors influeruing 'maintenance of self-esteem' were found to be the length of the hemodialysis experience and self-actualization. 8) The factors influencing 'transitional life' were found to be age, religion, economic situation, employment status. locus of control. past experiences and whether there was a plan for a kidney transplant.

• 보건교육건강증진학회지
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• 제29권5호
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• pp.13-26
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• 2012

Objectives: The purpose of this study was to identify the relationship between resilience of migrant workers and their mental health for improving their quality of life and adaptation in Korean society. Methods: Data were collected from March 21 to May 7, 2011. The participants included 488 migrant workers who lived in Busan Metropolitan City or Gyoungnam province. Results: First, heavy working burdens and lack of rests, low wages, poor living environments, low economic status & deficiency of living necessities, hard physical labors, and conflicts with Korean workers had negative effects on mental health. Second, high perceived stress caused by usual 'living difficulties', high 'cutural shock', high feeling of 'social isolation', and high discomfort from 'lack of Korean language proficiency' gave negative effects on migrant worker's mental health. Third, the most important factor on the mental health was the 'cultural shock' among stressors. Even though many stressors existed among migrant workers, these negative effects on mental health were lessened by their high resilience level. Conclusions: This study highlights the importance of migrant workers in Busan, Korea. To improve their mental health, social support including financial supports and educational programs that foster resilience needed.

• 한국소음진동공학회논문집
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• 제12권5호
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• pp.389-396
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• 2002

In this study, the dynamic absorbing system for gas operated gun has been investigated. For this purpose, firstly. mathematical model of gas-operated shoulder-fired gun has been constructed. Through a series of experimental works using the devised test setup, the characteristic behavior of mathematical model was compared to the test results. In order to design the dynamic absorbing system, parameter optimization process has been performed based on the simplified isolation system under constraints of moving displacement and transmitted force. In order to implement the more efficient dynamic absorbing system, the characteristic performance of stroke-dependent variable damping system has been analyzed with some opening area curves. Finally, the performance of the designed dynamic absorbing system has been evaluated by simulation and experiment using the previous test apparatus.

• 한국초지조사료학회지
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• 제40권4호
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• pp.285-290
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• 2020

To understand the role of small heat shock protein (sHSPs) in rice plant response to various stresses such as the heat and oxidative stresses, a cDNA encoding a 24.1 kDa mitochondrial small HSP (Oshsp24.1) was isolated from rice by rapid amplification of cDNA ends (RACE) PCR. The deduced amino acid sequence shows very high similarity with other plant small HSPs. DNA gel blot analysis suggests that the rice genome contains more than one copy of Oshsp24.1. High level of expression of Oshsp24.1 transcript was observed in rice seedlings in response to heat, methyl viologen, hydrogen peroxide, ozone, salt and heavy metal stresses. Recombinant OsHSP24.1 protein was produced in E. coli cells for biochemical assay. The protein formed oligomeric complex when incubated with Sulfo-EGS (ethylene glycol bis (succinimidyl succinate)). Our results shows that Oshsp24.1 has an important role in abiotic stress response and have potential for developing stress-tolerant plants.

• 한국작물학회지
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• 제47권1호
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• pp.62-67
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• 2002

An efficient system of rice microspore culture could contribute to the production of genetically modified rice. The microspores were isolated by mechanical or shed methods. The number of microspores per 100 anthers isolated at uninucleate stage was higher than (or similar to) those at binucleate stage in isolation method with pestle or spatular, but microspore divisions were not easily observed on both stages. On the other hand, pollen division in shed pollen culture was observed more frequently at uninuclear than at binuclear stage. Cold pretreatment at 1$0^{\circ}C$ for 10 days resulted in the best multicellular division to produce microcalli at 12.5% efficiency in shed microspores. Heat shock at 33$^{\circ}C$ for one hour before or after pollen shedding enhanced cell division and callus formation. Out of twelve green regenerants, two were haploids and ten were diploids based on the chromosome analysis of root tips. The size of stoma was 12$^{m}$ m in haploids and 15 ${\mu}{\textrm}{m}$ in diploids determined by scanning electron microscope (SEM).

• 대한조선학회논문집
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• 제46권2호
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• pp.165-170
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• 2009

Most of the naval shipboard equipments strongly require isolation devices to keep their performance and durability from severe noise and vibration loading. The rubber mount is well-known as one of most effective way to isolate major equipments from noise and vibration. The performance of the rubber mount is determined by characteristics of shock stiffness and vibration stiffness and the frequency range of interest is up to several Kilo Hz in navy vessels. In this study, an vibration experiment method for the rubber mount has been developed as a foundation work for assessing dynamic stiffness up to high frequency. Also experiments for a typical rubber mount has been carried out and the results has been discussed.