• 한국식품영양과학회지
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• 제25권3호
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• pp.478-483
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• 1996

The aroma components of Korean green tea in the south western part of Mt. Chiri prepared by the traditional method from native variety were analyzed using GC and GC-MS. The patterns on GC chromatograms of the three samples from the flushes plucked in early spring were similar, though they are prepared by different producers in the area of Hadong-kun, Kyung sang nam-do. A total of 51 aroma compounds were identified in all samples. Main component in the aroma compounds of these teas were geraniol, benzyl alcohol, 2-phenylethanol, $\beta$-ionone, benzyl cyanide and linalool oxides. The aroma components of green teas manufactured by the different plucking periods were also compared. The amounts of geraniol, typical rose floral aroma were particularly decreased in the final plucking period. The amounts of pyrazines and furfuryl alcohol, typical roasted aroma and nutty aroma were slightly increased in later plucking period.

• 한국압력기기공학회 논문집
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• 제11권2호
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• pp.51-60
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• 2015

Local wall thinning and integrity degradation caused by several mechanisms, such as flow accelerated corrosion, cavitation, flashing and/or liquid droplet impingement, is a main concern in secondary steam cycle piping system of nuclear power plants in terms of safety and operability. Thinned pipe management program (TPMP) has being developed and optimized to reduce the possibility of unplanned shutdown and/or power reduction due to pipe failure caused by wall thinning. In this paper, newest technologies, standards and regulations related to the integrity assessment, repair and replacement of thinned pipe component are reviewed. And technical improvement items in TPMP to secure the reliability and effectiveness are also presented.

• 한국의류학회지
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• 제24권7호
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• pp.1081-1087
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• 2000

Gromwell colorants were extracted with methanol and dried. Four fractions were obtained by silica gel adsorption column chromatography using step-wise elution method. Relative ratio of four fraction is 1.00:0.07:0.22:0.30(Fl:F2:F3:F4) and gromwell colorants mainly consist of Fl, F3 and F4. IR analysis shows that each fraction has similar structure. Main component of gromwell extracts is acetyl derivative of naphthoquinone, and the rest are isobutyl derivative and isovaleryl derivative etc., in order. Gromwell colorants exhibit relatively good affinity to protein and polyamide fibers, but low affinity to cellulose and regenerated cellulose fibers.

• 한국응용과학기술학회지
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• 제12권2호
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• pp.75-83
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• 1995

1, 3-Di(2-dodecanoylaminoethyl)-2, 7-dioxy-1, 3, 6, 8-tetraazacyclodecane[DDTD] and sorbitan monostearate(SMS) were synthesized as a main component for softner. O/W type softner(DSA) was prepared by blending of DSA, SMS, polyoxyethylene(10) castor oil, glyceryl monooleate, and polyoxyethylene(7) stearyl ether. After treatment of DSA to all cotton fabrics, the physical properties such as tear strength, crease recovery, and flexing abrasion resistance were measured. As a result of the measurement, DSA was found to be durable softner with good softness.

• 한국응용과학기술학회지
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• 제12권2호
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• pp.65-73
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• 1995

1, 3-Di(dodecanoyl)-2, 7-dioxy-6, 8-di(2-hydroxyethyl)-1, 3, 6, 8-tetraazacyclodecane(DDDT) and pentaerythritol monostearate(PMS) were synthesized as a main component for softner. O/W type softner(DPSA) was prepared by blending DDDT and PMS with polyoxyethylene(10) castor oil, polyoxyethylene(20) oleyl ether, and polyoxyethylene(10) monolaurate. After treatment of DPSA to all cotton fabrics, the physical properties such as tear strength, crease recovery, and flexing abrasion resistance were measured. As a result of the measurement, DPSA was proved to be durable softner with good softness.

• 한국응용과학기술학회지
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• 제20권4호
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• pp.341-345
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• 2003

Organic acid salt of fatty polyamide (DDDT) and acrylate of fatty carbamide (DDTCA) were synthesized as a main component for the softener. O/W type non-ionic softener (NSC) was prepared by blending DDDT and DDTCA with beef tallow, lanolin anhydride. polyoxyethylene(7) stearyl ether, and polyoxyethylene(50) oleyl ether. After treatment of NSC to all cotton fabrics, the physical properties such as tear strength, crease recovery, and flexing abrasion resistance were measured. As a result of the measurement, NSC was proved to be durable non-ionic softener with good softness.

• 한국자동차공학회논문집
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• 제4권4호
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• pp.38-45
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• 1996

Power steering systems play an important role for the vehicle handling characteristics and driver's steering center feeling during straightforward driving situation. In this paper, the rotary valve, the main component of power steering systems, is modeled and analyzed, and is combined with a 3-DOF(degree of freedom) lateral dynamics model of passenger cars to examine the effects of design parameters on the vehicle steering characteristics. The results can be applied to the development of advanced power steering systems for passenger cars such as electronically-con-trolled power steering system.

• 한국정밀공학회지
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• 제27권9호
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• pp.94-102
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• 2010

The spindle is the main component in machine tools. To develop high speed machine tools, a lot of studies have been carried out for high speed spindle. Bearing is very important part in spindle. The bearing clearance is influenced by shrink fit and thermal expansion during operation. The designer must take into account the reduction of shrink fits. The aims of this study are to grasp the shrink fits and behavior of a bearing which is a deeply connected with fatigue life of bearing and performance of spindle through FEM(Finite Element Method). This paper proposed optimum value of shrink fit considering deformation of spindle and stress of fitting area using design of experiments. Thus, the proposed formula can be used to obtain bearing internal clearance.

• 동력기계공학회지
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• 제14권1호
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• pp.11-15
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• 2010

Our environment is faced with serious problems related to the air pollution from automobiles in these days. In particular, the exhaust emissions from the diesel engines are recognized as main cause which has a great influence on environment. In this study, the potential of biodiesel fuel and oxygenated fuel(ethylene glycol mono-n-butyl ether; EGBE) was investigated as an effective method of decreasing the smoke emission. The smoke emission of blending fuel(EGBE 0~20 vol-%) was reduced in comparison with diesel fuel and it was reduced approximately 64% at 2000 rpm, full load in the 20% of blending rate. On the contrary NOx emissions from biodiesel fuel and EGBE blended fuel were increased compared with diesel fuel. Torque and brake specific energy consumption(BSEC) didn't have large differences.

• 한국소음진동공학회논문집
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• 제17권9호
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• pp.785-796
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• 2007

This study offers a design procedure of optimum cable damper for multi-mode vibration control with nonlinear damper and also investigates the relation between mode and amplitude dependency. The proposed multi-mode damping index, which is defined as a potential energy loss ratio of cable vibration, is a main component of optimization problem of optimum nonlinear damper. In order to include the amplitude dependency of nonlinear damper, three types of multi-mode patterns such as ambient vibration, support excitation and rain-wind induced vibration are assumed. The optimum damper exponent depends on amplitude patterns. In case of ambient vibration, optimum factor is less than 0.5 and in case of support excitation or rain-wind induced vibration it is between 0.5 and 1.0.