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The influence of the initial strains of the highly elastic plate on the forced vibration of the hydro-elastic system consisting of this plate, compressible viscous fluid, and rigid wall

  • Akbarov, Surkay D.;Ismailov, Meftun I.;Aliyev, Soltan A.
    • Coupled systems mechanics
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    • v.6 no.4
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    • pp.439-464
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    • 2017
  • The hydro-elastic system consisting of a pre-stretched highly elastic plate, compressible Newtonian viscous fluid, and the rigid wall is considered and it is assumed that on the plate a lineal-located time-harmonic force acts. It is required to investigate the dynamic behavior of this system and determine how the problem parameters and especially the pre-straining of the plate acts on this behavior. The elasticity relations of the plate are described through the harmonic potential and linearized (with respect to perturbations caused by external time-harmonic force) form of these relations is used in the present investigation. The plane-strain state in the plate is considered and the motion of that is described within the scope of the three-dimensional linearized equations of elastic waves in elastic bodies with initial stresses. The motion of the fluid is described by the linearized Navier-Stokes equations and it is considered the plane-parallel flow of this fluid. The Fourier transform with respect to the space coordinate is applied for a solution to the corresponding boundary-value problem. Numerical results on the frequency response of the interface normal stress and normal velocity and the influence of the initial stretching of the plate on this response are presented and discussed. In particular, it is established that the initial stretching of the plate can decrease significantly the absolute values of the aforementioned quantities.

Aseptic Germination of F1 Hybrid Seed by Inter-species Pollination of Calanthe discolor Lindl. and C. discolor for. Sieboldii (Decne.) Ohwi (새우난초(Calanthe discolor Lindl.)와 금새우난초[C. discolor for. sieboldii (Decne.) Ohwi]의 종간교배에 의한 1대잡종 종자의 기내무균 발아)

  • Kim, Kwang-Soo;Kim, Jong-Sun;Park, Jong-Hwan
    • Korean Journal of Plant Resources
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    • v.21 no.4
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    • pp.341-345
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    • 2008
  • Two orchid species of Calanthe discolor Lindl. and C. discolor for. sieboldii (Decne.) Ohwi, which have different form flower color and size. They were crossed in mid April by artificial pollination, and the F1 hybrid seeds were collected mid October. Germination of seeds was investigated on pre-treatment of seeds and under the various environmental conditions. Germination was promoted by moisture absorption and ultrasonic treatment of seeds. Dark culture of F1 hybrid seeds enhanced germination and protocorm formation, and development into seedlings compared with light culture. Although, plant growth regulators such as NAA and BA had a slightly promotive effect on seed germination and protocorm growth, regenerated seeding were showed abnormal growth patterns. Regenerated F1 hybrid plantlets were successfully transferred to pot.

A Compensation Technique for Dispersive and Resonant Wideband Antenna using Stable Minimum-Phase ARMA System Modeling for Coherent Impulse Communication Systems (안정성을 갖는 최소 위상 ARMA 시스템 모델링을 이용한 코히어런트 임펄스 통신 시스템의 광대역 안테나 확산 및 공진 특성 보상 기법)

  • Lee Won-Cheol;Park Woon-Yong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.10 s.89
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    • pp.983-995
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    • 2004
  • This paper introduces a pre-compensation filter for compensating dispersive and resonant properties experienced along the usage of non-ideal wideband antennas in impulse communication systems. It has been well blown that the transmitted impulse signal becomes deformed because of dispersive and resonant characteristics. Accordingly, in spite of using ideal template signal at the correlator in coherent receiver, these impairments degrade overall performance attributed to low level of coherence. To overcome this problem this paper exploits a realization technique of pre-compensation filter purposely installed at transmitter whose stability is automatically guaranteed because it has an inversion form of minimum-phase ARMA (Auto-Regressive Moving Average) system. The performance of proposed scheme will be shown in results from computer simulations to verify its affirmative impact on impulse communication system with regarding several distinctively shaped antennas.

A Preliminary study for the evaluation of the effects of EFT-I(EFT program for insomnia) for insomnia in the elderly (노인 불면에 대한 EFT 불면 치료 프로그램(EFT-I)의 효과 평가를 위한 예비적 연구)

  • Lee, Jung-Hwan;Suh, Hynu-Uk;Chung, Sun-Yong;Kim, Jong-Woo
    • Journal of Oriental Neuropsychiatry
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    • v.22 no.4
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    • pp.101-109
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    • 2011
  • Objectives : The aim of this study was to evaluate the effects of EFT-I(EFT program for insomnia) for insomnia in the elderly as a preliminary study. Methods : This study was a single group pre-post comparative study that involved 10 elderly women(mean age=$76.3{\pm}4.29$), who visited a senior welfare center, complained of insomnia symptoms. Subjects received 8 sessions(twice a week for 4 weeks and 1 hour for each session) of EFT-I group training. Insomnia severity, depression, state-anxiety, and life satisfaction of each subject were evaluated twice at pre and post of EFT-I. Korean Sleep Scale, Short form of Geriatric Depression Scale(SGDS), State-Trait Anxiety Inventory(STAI), and life satisfaction scale were used as evaluation tools. The data were analyzed using paired-samples T-test. Results : Insomnia severity, life satisfaction, depression, and state-anxiety were significantly improved by EFT-I. Conclusions : Result of this study showed that EFT-I can be a useful treatment program for elderly insomnia. Larger clinical trials are needed to verify effect of EFT-I as a community based insomnia management program for the elderly.

Assessment of Village Health Worker Training Program in Tuguegarao, Philippine

  • Kim, Jung-Min;Koh, Kwang-Wook;Oak, Chul-Ho;Jung, Woo-Hyuk;Kim, Sung-Hyun;Park, Dae-Hee
    • Journal of Preventive Medicine and Public Health
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    • v.42 no.6
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    • pp.377-385
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    • 2009
  • Objectives : This study was performed to evaluate the effectiveness of 'village health worker training program' which aimed to build community participatory health promotion capacity of community leaders in villages of low developed country and to develop methods for further development of the program. Methods : The intervention group were 134 community leaders from 25 barangays (village). Control group were 149 form 4 barangays. Intervention group participated 3-day training program. Questionnaire was developed based on 'Health Promotion Capacity Checklist' which assessed capacity in 4 feathers; 'knowledge', 'skill', 'commitment', and 'resource'. Each feather was assessed in 4 point rating scale. Capacity scores between intervention group and control group were examined to identify changes between the pre- and post-intervention periods. A qualitative evaluation of the program was conducted to assess the appropriateness of the program. The program was conducted in Tuguegarao city, Philippine in January, 2009. Results : The result showed significant increases in the total health promotion capacity and each feather of health promotion capacities between pre and post assessment of intervention group. But there was no significant change in that of control group. Participants marked high level of satisfaction for preparedness, selection of main subjects and education method. Qualitative evaluation revealed that training program facilitated community participatory health promotion capacity of participants. Conclusions : This study suggested that the Village health worker training program is effective for building health promotion capacity of community leaders and it can be a main method for helping low developed countries with further development.

The Effect of Sa-am acupuncture on Knee Osteoarthritis

  • Min, Moo-Hong;Choi, Yeong-Gon;Kim, Yun-Ju;Park, Hi-Joon;Lee, Sam-Chool;Joo, Ho-No;Han, Seung-Moo;Lim, Sa-Bi-Na
    • Korean Journal of Acupuncture
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    • v.26 no.4
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    • pp.53-66
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    • 2009
  • Objective : Acupuncture has been widely used throughout the world for the treatment of knee osteoarthritis (knee OA). This study investigated whether acupuncture, particularly Sa-am acupuncture, could be effective in relieving pain and improving the symptoms of knee OA. Method : This study was conducted as a prospective, randomized, controlled, and patient- and investigator-blinded clinical trial. Forty volunteers with knee OA participated in the study. All participants were screened through an inclusion and exclusion criteria. Thirty four participants completed the clinical trial. In total, forty subjects were randomly selected to receive Sa-am acupuncture. Eight sessions of acupuncture were given at the contralateral side of the problematic knee for 4 weeks. Korean translation of Western Ontario and McMaster Universities Osteoarthritis Index (KWOMAC) scores were measured twice: at the beginning and end of the clinical trial period. Both the Patient Global Assessment and physical health scores based on the 36-Item Short-Form Health Survey were also used to measure the results. Results : Compared to the pre-trial scores, the Sa-am acupuncture group (n=34) showed a significant decrease in KWOMAC total scores according to a paired t-test. The Sa-am acupuncture group also showed significant improvement in the Patient Global Assessment when compared to the pre-trial. Conclusions : Sa-am acupuncture for knee OA resulted in an improved KWOMAC total score. This was mostly driven by the function component score that was greatly affected by acupuncture. However, further studies with expanded designs are needed to solidify this finding with scientific rigor.

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The Relationship of Dysfunctions Degree, Daily Living Activity, Depressiveness and Quality of Life among the Elderly Suffering from Stroke (뇌졸중 노인의 기능장애 정도, 일상생활 수행능력, 우울과 삶의 질 간의 관계)

  • Park, In-Sook;Kim, Do-Yeon;Kang, Chang-Yeol
    • The Korean Journal of Health Service Management
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    • v.5 no.2
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    • pp.173-186
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    • 2011
  • The purpose of this study was to know dysfunctions degree, daily living activity, depression and quality of life among stroke elderly person; and to know what kind of factors affecting to quality of life of the stroke elderly person; after that provide a fundamental data to nursing arbitration plan about increase height quality of life of the stroke elderly person. The study subjects were collected 119 people, over than 60 age, who were diagnosed with stoke in D hospital, living in B city. The data was collected by using personal interviews and questionnaire, from Nov 2008 to Jan 2009. The questionnaire were Pre-Stroke MRDS(Modified Rankin Disability Scale), Barthel-ADL(Activities of Daily Living), K-IADL(Korean-Instrumental Activities of Daily Living), GDS-15(Geriatric Depression Scale-15-question form) methods. The pre-stroke MRDS was appeared a functional obstacle. The mean score of activity of daily living was 18.24 which showed the subjects were mildly disabled, the score of instrumental activities of daily living was 7.94 which showed the mildly abled, and score of depressiveness was 7.41 which showed the subjects were mildly depression. There was a significantly correlation among MRDS, ADL, IADL, depressiveness and quality of life. Through these study result, important to check the old subjects' depressiveness, cognitive functions, daily living abilities, dysfunctions degree to main tain their quality of life.

Flexural Behavior of Steel-Concrete Composite Beams Strengthened by Post Tension Method (포스트 텐션 공법으로 보강된 SC 합성보의 휨 거동)

  • Ryu, Soo-Hyun;Kim, Heui-Cheol
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.3
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    • pp.186-195
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    • 2010
  • This study has attempted to suggest a proper reinforcement method by strengthening unbonded post -tensioning through height of an anchorage hole, form of a saddle, and loading time point as parameters and evaluating the reinforcement method through a bending experiment. The result of this experiment indicated effects of reinforcement since the maximum strength ratio(the ratio of an experimental value to theoretical value) of SC composite beams before prestressed was 0.97 and after prestress were 1.00~1.21. As a result of analysis on displacement and strain, irrespective of height of an anchorage hole and loading time point, the D120-series specimen where an anchorage hole was installed on the neutral axis after reinforcement showed that its deflection continuously increased without sudden load reduction after maximum load and it stably behaved with relatively low strain of each part. In terms of reinforcement effects, the maximum strength of SCR-UD120 specimen prestressed after pre-loading was increased 1.72 times comparing to SC composite beams so SCR-UD120 specimen prestressed after pre-loading was shown to be the best.

Design of Venturi Dump Surface for Pre-filming Airblast Injector (예막 공기충돌형 분사기의 벤추리 덤프면 설계)

  • Shin, Dongsoo;Choi, Myunghwan;Radhakrishnan, Kanmaniraja;Koo, Jaye;Jung, Seungchai
    • Journal of the Korean Society of Propulsion Engineers
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    • v.22 no.4
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    • pp.44-54
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    • 2018
  • In a spray experiment using a venturi mounted on a lean premixed LPP injector, droplets appear to have non-uniform distributions. To solve this problem, the exit angle of the venturi was changed to form a dump surface on the nozzle neck. The dump surface improved the atomization performance and minimized droplet loss while forming recirculation zone in the venturi exit. In order to solve the non-uniform spray of the injector, the flow characteristics inside the venturi and SMD of the spray are compared. Finally, an optimum venturi shape is selected to minimize the spray loss and improve the spray performance.

Antimicrobial and Cell Viability Measurement of Hypochlorous Acid against Streptococcus. mutans and Aggregatibacter. actinomycetemcomitans (미산성 차아염소산수의 S. mutans와 A. actinomycetemcomitans에 대한 살균 효과)

  • Song, Jiyeon;Kim, Jiyoung;Lee, Kyunghee
    • Journal of The Korean Society of Integrative Medicine
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    • v.7 no.2
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    • pp.141-151
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    • 2019
  • Purpose : Hypochlorous acid (HOCl), a major inorganic bactericidal compound of innate immunity, is effective against a broad range of microorganisms. In particular, HOCl is well-known as a non-antibiotic antimicrobial substance. However, effects of HOCl as an antimicrobial agent are still needed to study these functions against various specific type of microorganisms. In this study, we investigated the antimicrobial effect of hypochlorous acid (HOCl) in S. mutans and A. actinomycetemcomitans to cause dental caries and periodontal disease. Experiments were conducted to observe whether HOCl become effective replacement of disinfectant. Methods : To observe antimicrobial effect of HOCl, stabilized HOCl is prepared in the form of a physiologically balanced solution in pre-conditioned and post-conditioned HOCl solution. As a control, commercially available disinfectant MAXCLEAN was used as positive control. Moreover, S. mutans and A. actinomycetemcomitans distribution in gagrin, filtered tap water, and culture media. Cell viability were measured by viable cell count methods and disk diffusion test. Results : Our results showed that treatment of HOCl have no effect against antimicrobial effect compare to control group especially gagrin in disk diffusion test. HOCl tended to reduced viability against S. mutans in group of post-conditioned than pre-conditioned of HOCl solution however, there was no significant difference as well as no effect in A. actinomycetemcomitans. Conclusion : HOCl showed tendency to reduce viability against S. mutans in group of post-conditioned of HOCl solution and no effect of antimicrobial effect. Although HOCl is well known as effective against a broad range of microorganisms, HOCl seems to have diversity following type of species to be used as antimicrobial drug following our results. Therefore, it is necessary to be rigidly controlled and regulated in using HOCl solution clinically.