• Journal of the Semiconductor & Display Technology
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• v.10 no.1
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• pp.43-49
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• 2011

In this study, the dynamic characteristics of an air spring connected with an external chamber through a flexible tube are examined. The uncoupled dynamic parameters of the air spring are identified through experiments, followed by the suggestion of a model-based approach to obtain the remaining coupled dynamic parameters using the various frequency response functions derived in PART I paper [1]. To improve or control the damping characteristics of the air spring, this vibration isolation air spring system is physically established in laboratory scale. And we attempt to identify various parameters used to describe to air spring system by both theoretically [1] and experimentally, which is performed in this report. The damping parameter of the tube system is identified through experiments on the system incorporated with the air cylinder, and a nonlinear regression procedure is employed to find solutions. The resulting value is used to expect the frequency response function of dynamic pressure in the top chamber (air spring) with respect to that in the bottom chamber (external chamber). Comparison with the experimental data supports the validity of the present estimation procedures. Also, the dynamic mechanism of the damping effects particularly in a low frequency range is investigated through this experimental endeavor.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.4
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• pp.411-423
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• 2008

Pneumatic vibration isolator has a wide application for ground-vibration isolation of vibration-sensitive equipments. Recent advances In precision machine tools and instruments such as nano-technology or medical devices require a better isolation performance, which can be efficiently done by precise modeling- and design- of the isolation system. This paper will discuss an efficient transmissibility design method for pneumatic vibration isolator by employing the complex stiffness model of dual-chamber pneumatic spring developed in our previous research. Three design parameters of volume ratio between the two pneumatic chambers, the geometry of capillary tube connecting the two pneumatic chambers and finally the stiffness of diaphragm necessarily employed for prevention of air leakage were found to be important factors in transmissibility design. Based on design technique that maximizes damping of dual-chamber pneumatic spring, trade-off among the resonance frequency of transmissibility, peak transmissibility and transmissibility in high frequency range was found, which was not ever stated in previous researches. Furthermore this paper will discuss about negative role of diaphragm in transmissibility design. Then the design method proposed in this paper will be illustrated through experiment at measurements.

• Structural Engineering and Mechanics
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• v.61 no.5
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• pp.645-655
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• 2017

To determine the seismic applicability of a long-span railway concrete upper-deck arch bridge with concrete-filled steel-tube (CFST) rigid skeleton ribs, some fundamental principles and seismic approaches for long-span bridges are investigated to update the design methods in the current Code for Seismic Design of Railway Engineering of China. Ductile and mixed isolation design are investigated respectively to compare the structural seismic performances. The flexural moment and plastic rotation demands and capacities are quantified to assess the seismic status of the ductile components. A kind of triple friction pendulum (TFP) system and lead-plug rubber bearing are applied simultaneously to regularize the structural seismic demands. The numerical analysis shows that the current ductile layout with continuous rigid frame approaching spans should be strengthened to satisfy the demands of rare earthquakes. However, the mixed isolation design embodies excellent seismic performances for the continuous girder approaching span of this railway arch bridge.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.1
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• pp.110-122
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• 2008

Pneumatic vibration isolator typically consisting of dual-chamber pneumatic springs and a rigid table are widely employed for proper operation of precision instruments such as optical devices or nano-scale equipments owing to their low stiffness- and high damping-characteristics. As environmental vibration regulations for precision instruments become more stringent, it is required to improve further the isolation performance. In order to facilitate their design optimization or active control, a more accurate mathematical model or complex stiffness is needed. Experimental results we obtained rigorously for a dual-chamber pneumatic spring exhibit significantly amplitude dependent behavior, which cannot be described by linear models in earlier researches. In this paper, an improvement for the complex stiffness model is presented by taking two major considerations. One is to consider the amplitude dependent complex stiffness of diaphragm necessarily employed for prevention of air leakage. The other is to employ a nonlinear model for the air flow in capillary tube connecting the two pneumatic chambers. The proposed amplitude-dependent complex stiffness model which reflects dependency on both frequency and excitation amplitude is shown to be very valid by comparison with the experimental measurements. Such an accurate nonlinear model for the dual-chamber pneumatic springs would contribute to more effective design or control of vibration isolation systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.421-431
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• 2016

The purpose of this study was to identify the influence of depression, social isolation, and meaning in life on the swallowing related quality of life in patients with dysphagia. In this study, 87 the dysphagia patients diagnosed with stroke, degenerative disease, and neurological disorder in a general or rehabilitation hospital in Seoul, Gyeonggi, and Incheon were assessed. The data were collected between February and April, 2015 using CES-D, RULS, PIL, SWAL-QOL. The data were analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation, and stepwise multiple regression with SPSS 22.0. Of the participants, 20.7% reported having had depression, 92.0% middle-high social isolation and 64.4% existential vacuum. The mean scores were SWAL- QOL 158.89(35.97). Stepwise multiple regression revealed that tube feeding to have the greatest effect on SWAL-QOL(${\beta}=-0.57$, p<.001), followed in order by age (${\beta}=0.26$, p=.001), lower MIL (${\beta}=0.19$ p=.014), and education (${\beta}=0.17$, p=.032). The most influential factor to SWAL-QOL was tube feeding. These variables accounted for 50.7% of SWAL-QOL in dysphagia patients (F=28.84 p=.031). Therefore, it is essential to develop the intervention that can improve the meaning in life in patients with dysphagia. In addition there is a need to study the psychological factors and quality of life of tube feeding.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.2
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• pp.129-134
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• 2014

Two neuropeptides were purified from the acidified tube feet extract of the starfish Asterias amurensis by C18 reversed phase and size-exclusion high-performance liquid chromatography (HPLC). The tube feet extract and the purified peptides (AST-I and AST-II) showed potent contractile activity on dorsal retractor muscle (DRM) of the starfish Asterina pectinifera and intestine (smooth muscle) of the panther puffer Takifugu pardalis. Treatment of the purified peptides with dithiothreitol (DTT) for 60 min at $37^{\circ}C$ significantly altered their retention times, suggesting that these compounds contained disulfide bonds. The molecular weights of AST-I and AST-II were determined to be 2064.2 Da and 6137.2 Da, respectively, by MALDI-TOF mass spectrometry.

• Korean Journal of Microbiology
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• v.16 no.3
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• pp.111-121
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• 1978

About 40 temperature-sensitive mutants have been isolated as a preliminary step to study the spore germination, the cell cycle, and the control of macromolecular synthesis in Aspergillus nidulans. To obtain temperature-sensitive mutants rapidly and effectively, the selective enrichment method using antifungal antibiotic nystatin was developed. Based on the data which had applied to the concentration of auxotrophic mutants by the earlier investigators, the optimal concentration and the time of treatment at the nonpermissive temeprature were determined as 50 to 100 units per ml and 4.5 hr., respectively. Out of 41 ts mutants assigned to the strain symbol PK, thirteen that seemed to be arrested at the earlystage of spore germination were subjected to the further cytological and genetic analysis. Elght of these mutants are able to form germ tube and five not. Staining with acid fuchsin for the 5PK strains shows that one irreversible mutant, PK6 strain able to form germ tube, accumulate mitotic spindle, being arrested in mitosis. Another PK15 and PK23 strain have more than one intact nucleolus without germ tube formation at the restrictive temperature. the temperature-senstive mutation in PK12 strain, the onlystrain which is able occurred in certain gene specific for the germination of spore. All of the ts markers are recessive and complement each other in heterokaryon between two different ts markers at the restrictive temperature.

• Korean Journal of Veterinary Research
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• v.18 no.1
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• pp.19-22
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• 1978

In order to isolate and identify Anaplasma bodies, two dairy cattle were inoculated with the whole blood of Korean cattle reacted to capillary tube agglutination test (Ana-test). The results obtained are as follows: 1. In the infected dairy cattle, Anaplasma bodies were first detected between 30 to 40 days post infection. 2. The isolates were identified as Anaplasma centrale on the basis of morphology of infected anaplasma bodies in erythocytes.

• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.13-22
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• 2006

The geotextile have been used in filtration and drainage for over 30 years in many applications of civil and environmental projects. Geotextile tube is compound technology of filtration and drainage property of geotextile. Geotextile have been used for various types of containers, such as small hand-filled sandbags, 3-dimensional fabric forms for concrete paste, large soil and aggregate filled geotextile gabion, prefabricated hydraulically filled containers, and other innovative systems involving containment of soils using geotextile. They are hydraulically filled with dredged materials. It have been applied in coastal protection and scour protection, dewatering method of slurry, and isolation of contaminated material. Recently, geotextile tube technology is no longer alternative construction technique but suitable desired solution. This paper presents the behavior of geotextile tube composite structure by 2-D limit equilibrium and plane strain analysis. 2-D limit equilibrium analysis was performed to evaluate the stability of geotextile tube composite structure for the lateral load and also the plane strain analysis was conducted to determine the design and construction factors. Based on the results of this paper, the three types of geotextile tube composite structure is stable. And the optimum tensile strength of geotextile is 151kN/m and maximum pumping pressure is 22.7kN/m.

• Korean Journal of Veterinary Research
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• v.40 no.2
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• pp.339-343
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• 2000

Isolation and identification, prevalence and density of Setaria microfilariae(mf) were investigated in the blood of 406 cattle slaughtered at the abatoirs in Yungnam province from February 1999 to March 2000. Nine ml of blood from the jugular vein was collected in a test tube including EDTA respectively. The blood was mixed(10 : 1) with 0.2% Saponin in saline solution. This mixture was diluted again(1 : 10) with saline solution and stirred. This diluted mixture was filtered using Millipore membrane filter with a pore size of $3.0{\mu}m$. Mf were recovered from the membrane in saline solution. Mf isolated were identified as Setaria digitata on the basis of morphologic characteristics. Infection rate of the mf of total 406 cattle was revealed as 6.40%. Seasonal prevalences of the mf were presented 9.46%(7/74) in Autumn, 7.05%(11/156) in Summer, 4.65%(4/86) in Winter and 4.44%(4/90) in Spring respectively. Average density of the mf of every 9ml blood in 26 positive cattle was revealed as 170(2-641) worms. Seasonal densities of the mf of 9ml blood were presented average 361(160-641) worms in Autumn, 205(16-620) worms in Summer, 108(6-204) worms in Spring, 6(2-11) worms in Winter respectively.