• Journal of the Korean Applied Science and Technology
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• v.15 no.4
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• pp.45-56
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• 1998

Methyl fructoside oleic acid polyester(MFPE), fructose-based sugar polyester, was synthesized by solvent-free, soap-free transesterification of methyl oleate with methyl fructoside(MF) as a sugar starting material in the presence of conventional potassium carbonate basic catalyst. Methyl fructoside was found to be an effective sugar starting material, because of its low softning point, high heat stability, high miscibility, and high reactivity than other sugars. Yield 98% of purified MFPE based on initial weight of MF was obtained at 1:5 of the molar ratio of methyl fructoside to methyl oleate, 2%(w/w) of potassium carbonate catalyst content, 20${\sim}$200mmHg of reduced pressure and $180^{\circ}C$ of reaction temperature. MFPE structure was confirmed by infrared and proton nuclear magnetic resonance spectroscopy. Physical properties of methyl of fructoside oleic acid polyester such as viscosity, HLB, solubility, color, refractive index, specific gravity, and density were similar to physical properties of sucrose polyesters(SPE) and vegetable oils. Then, it was elucidated that MFPE was sufficient to replace the SPE and conventional oils.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.8
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• pp.849-855
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• 2008

An experimental method based on contact resonance is developed to extract the contact parameters of mechanical joints under various clamped conditions. Mechanical joint parameters of shear contact stiffness and damping were extracted for different physical joint parameters such as surface finish of the mating surfaces, the presence of lubrication, the effect of the clamping pressure, and shear load. It was found that the shear contact stiffness values decreased with increasing clamping load and increased with increasing shear loading. Contact damping ratio values were almost constant with clamping load, but decreased with increasing shear load. Moreover, rough surfaces exhibited the highest shear stiffness and contact damping compared to smooth surfaces.

• Speech Sciences
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• v.10 no.2
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• pp.145-157
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• 2003

Vowels are classified by the shapes of vocal tract. These shapes form constriction points along the tract, which have an influence on such vocal tract resonance as F1, F2, F3, and so on. The formant frequency is influenced by aperture and placement of tongue and the intensity is influenced by air pressure of subglottis. The object of this study compares to characterize the spectral outputs of oral and nasal spectra for the formant frequencies and intensity of Korean oral vowels. Subjects consisted of 20 normal persons (10 male and 10 female) without laryngeal pathology. The speech sample included /a/, /e/, /i/, /o/, /u/ of Korean oral vowels. The spectrum of each vowel was analysed by Nasal View and Real Analysis Program using Dr. Speech. The result showed that nasal intensity is decreased manifestly from F1 to F2. But oral intensity and Intensity is decreased little bit from F1 to F2. The most of values of nasal formant frequency is similarity oral formant frequency and Formant frequency or little bit smaller.

• Journal of Ocean Engineering and Technology
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• v.19 no.6 s.67
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• pp.16-21
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• 2005

In the design of super tankers or LNG carriers, which transport a large amount of liquid in the cargo tanks, the structural d11mage due to liquid sloshing is an important problem. The impact pressure from sloshing is most violent when the liquid motion of a partially filled tank is in resonance with the motion of a ship. In this study, the sloshing natural periods of a baffled tank, often installed to reduce liquid motion, is analyzed. A variational method is adopted to estimate the sloshing natural periods for a prismatic cargo tank with baffles of arbitrary filling depth of liquid; the results are compared with Lloyd's Register regulations on sloshing periods. In this study, using an effective liquid-fill-depth concept, sloshing periods for a baffled tank can be expressed by the same form as rectangular prismatic tanks without baffles. In contrast to Lloyd's Register regulations, which can be applicable only to cargo tanks with constant baffle size and distribution, the present results can be applicable to cases of variable baffle size and distribution.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.3
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• pp.68-77
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• 1995

Characteristics of electron cyclotron resonance (ECR) plasma thermal oxide grown at low-temperature have been investigated. The effects of several process parameters such as substrate temperature, microwave power, gas flow rate, and process pressure on the growth rate of the oxide have been also investigated. It was found that the plasma density, reactive ion species, is strongly related to the growth rate of ECR plasma oxied. It was also found that the plasma density increases with microwave power while it decreases with decreasing O2 flow rate. The oxidation time dependence of the oxide thichness showed parabolic characteristics. Considering ECR plasma thermal oxidation at low-temperature, the linear as well as parabolic rate constants calculated from fitting data by using the Deal-Grove model was very large in comparison with conventional thermal oxidation. The ECR plasma oxide grown on (100) crystalline-Si wafer exhibited good electrical characteristics which are comparable to those of thermal oxide: fixed oxide charge(N$_{ff}$)= 7${\times}10^{10}cm^{-2}$, interface state density(N$_{it}$)=4${\times}10^[10}cm^{-2}eV^{-1}$, and breakdown field > 8MV/cm.

• The Journal of the Acoustical Society of Korea
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• v.35 no.4
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• pp.288-294
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• 2016

The space between tire and wheel guard acts as a path for tire pattern noise transmission. In this study, acoustic phenomenon occurring in the tire-wheel guard space is investigated using acoustic mode analysis and visualization of the sound pressure distribution over the wheel guard surface. We introduced a cavity over the wheel guard surface to reduce the tire pattern noise, where the cavity acts as an acoustic damper. The interior noise was reduced by 2 dB(A), and the noise control measures treated in this study may provide an efficient method to improve interior sound quality without increasing cost and weight at the final stage of the vehicle development.

• Journal of Korean Critical Care Nursing
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• v.2 no.1
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• pp.26-35
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• 2009

Purpose: This paper reviews current diagnostic evaluation, treatment, nursing considerations, and the nurse practitioner’s (NP) role in acute ischemic stroke care. Methods: National guidelines and extensive literature on acute stroke care were reviewed and a relevant clinical case was introduced. Results: Computerized tomography (CT) of the head without contrast is the initial brain imaging procedure for patients with an acute stroke. Magnetic resonance imaging (MRI) can be an alternative test. Restoration of cerebral perfusion to the affected area is a key therapeutic strategy for ischemic stroke. A number of treatment strategies such as thrombolysis, anticoagulation, antiplatelet, and surgical treatment can be selected to improve blood flow to the ischemic region. The NP on the stroke team is involved with immediate stroke management including neurological assessment, ensuring adequate oxygenation, blood pressure management, activity, and diet. Discharge planning with the patient, family teaching and coordination of follow up care should also be implemented early in the hospitalization. Conclusion: The nurse practitioner is one of the cardinal members on the stroke team, and must be updated with current treatment and management guidelines.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.3
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• pp.173-183
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• 1993

Four wave gauges of pressure type were installed for about one month(1992. 2~3) for the analysis of wave agitations induced by the intrusion of long-period incident waves inside and outside of Donghae Harbor. Helmholtz natural period and second peak period of seiche in Donghae Harbor are found to be approximately 17.1 and 5.5 minutes from the spectral analysis of measured long-period wave data. Amplification ratio at Helmholtz natural period reaches about 10 which is five times as lagre as that of Youngil Bay, but wave amplitudes ill harbor were about 10 em during the measurement period which are relatively small.

• Clinical and Experimental Pediatrics
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• v.54 no.1
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• pp.40-44
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• 2011

We present a case of tacrolimus-induced encephalopathy after successful kidney transplantation. An 11-year-old girl presented with sudden onset of neurologic symptoms, hypertension, and psychiatric symptoms, with normal kidney function, after kidney transplantation. The symptoms improved after cessation of tacrolimus. Magnetic resonance imaging (MRI) showed acute infarction of the middle cerebral artery (MCA) territory in the right frontal lobe. Three days later, she had normal mental function and maintained normal blood pressure with left hemiparesis. Follow-up MRI was performed on D19, showing new infarct lesions at both cerebral hemispheres. Ten days later, MRI showed further improvement, but brain single photon emission computed tomography (SPECT) showed mild reduction of uptake in both the anterior cingulate gyrus and the left thalamus. One month after onset of symptoms, angiography showed complete resolution of stenosis. However, presenting as a mild fine motor disability of both hands and mild dysarthria, what had been atrophy at both centrum semiovale at 4 months now showed progression to encephalomalacia. There are two points of interest in this case. First, encephalopathy occurred after administration of tacrolimus and improved after discontinuation of the drug. Second, the development of right-side hemiplegia could not be explained by conventional MRI; but through diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) of white matter tract, visualization was possible.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.5
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• pp.380-388
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• 2002

This paper describes the optimum design for low-pressure steam turbine rotor of 1,000 MW nuclear power plant by using a combined genetic algorithm, which uses both a genetic algorithm and a local concentrate search algorithm (e.g. simplex method). This algorithm is not only faster than the standard genetic algorithm but also supplies a more accurate solution. In addition, this algorithm can find the global and local optimum solutions. The objective is to minimize the resonance response (Q factor) and total weight of the shaft, and to separate the critical speeds as far from the operating speed as possible. These factors play very important roles in designing a rotor-bearing system under the dynamic behavior constraint. In the present work, the shaft diameter, the bearing length, and clearance are used as the design variables. The results show that the proposed algorithm can improve the Q factor and reduce the weight of the shaft and the 1st critical speed.