• Food Science and Biotechnology
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• v.17 no.2
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• pp.417-420
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• 2008

Rheological properties of sweet potato starch (SPS)-glucose composites (5%, w/w) at different concentrations (0, 10, 20, and 30%, w/w) of glucose were investigated in steady and dynamic shear. The steady shear rheological properties of SPS-glucose composites were determined from rheological parameters for power law and Casson flow models. At $25^{\circ}C$ all the samples showed a pronounced shear-thinning behaviors (n=0.29-0.37) with high Casson yield stress. In general, the presence of glucose resulted in the decrease in consistence index (K), apparent viscosity (${\eta}_{a,100}$), and yield stress (${\sigma}_{oc}$). Storage (G') and loss (G") moduli increased with an increase in frequency ($\omega$), while complex viscosity (${\eta}*$) decreased. Dynamic moduli (G', G", and ${\eta}*$) of the SPS-glucose composites at higher glucose concentrations (20 and 30%) were higher than those of the control (0% glucose) and also increased with increasing glucose concentration from 10 to 30%. The effect of glucose on steady and dynamic shear rheological properties of the SPS pastes appears to greatly depend on glucose concentration in the range of 10-30%.

• Journal of Astronomy and Space Sciences
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• v.18 no.1
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• pp.81-93
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• 2001

Far ultraviolet IMaging Spectrograph (FIMS) should be designed to maintain its structural stability and to minimize optical performance degradation in launch and in operation enviroments. The structural and thermal analyzes of grating and grating mount system, which are directly related to FIMS optical performance, was performed using finite element method. The grating mount was made to keep the grating stress down, while keeping the natural frequency of the grating mount higher than 100 Hz. Transient and static thermal analyzes were also performed and the results shows that the thermal stress on the grating can be attenuated sufficiently. The optical performance variation due to temperature variation was with the allowed range.

• Journal of the Earthquake Engineering Society of Korea
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• v.17 no.1
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• pp.21-31
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• 2013

In this study, dynamic characteristics and seismic capacity of the nuclear power plant piping system are evaluated by model test results using multi-platform shake table. The model is 21.2 m long and consists of straight pipes, elbows, and reducers. The stainless steel pipe diameters are 60.3 mm (2 in.) and 88.9 mm (3 in.) and the system was assembled in accordance with ASME code criteria. The dynamic characteristics such as natural frequency, damping and acceleration responses of the piping system were estimated using the measured acceleration, displacement and strain data. The natural frequencies of the specimen were not changed significantly before and after the testing and the failure and leakage of the piping system was not observed until the final excitation. The damping ratio was estimated in the range of 3.13 ~ 4.98 % and it is found that the allowable stress(345 MPa) according to ASME criteria is 2.5 times larger than the measured maximum stress (138 MPa) of the piping system even under the maximum excitation level of this test.

• Journal of the Korean Home Economics Association
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• v.31 no.3
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• pp.29-46
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• 1993

The purpose of this study were to investigate the relation between home management ability and family life satisfaction of home makers, and to find out variables which influence them. The data were collected though the questionnaire whose respondent were 408 home makers in Kwang Ju and Kang Reung. The data were analyzed by various statistical method such as Cronbach's coefficient, factor analysis, frequency, percentage, mean, F-test, t-test, Duncan's multiple range test, regression analysis and path analysis. The results were as follow. 1. Home management ability score showed 68.5. Influential variables on home management ability were the level of education (husband and wife), occupation of husband and income as sociodemographic variables, and degree of resourcefulness recognition and of communication as psychological variables. 2. Family life satisfaction score showed 74.6. Influential variables on home management ability were the level of education (husband), occupation of husband and income as sociodemographic variables, and degree of resourcefulness recognition, of communication and of stress recognition as psychological variables. 3. The degree of communication was the highest influential variable to have influence on family life satisfaction. And the degree of resourcefulness recognition, of stress recognition, occupation of husband and wife, level of education(husband), number of children were variables to have directly and/or indirectly influence on family life satisfaction.

• Journal of Animal Environmental Science
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• v.21 no.2
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• pp.47-54
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• 2015

Climate change has directly impacted environmentally dependent first industry. The changes of amount and frequency of precipitation have caused unstable drinking water supply for grassland and feed crop, and have changed the variety of grassland and feed crop. Rising temperature has caused heat stress on livestock, which has impacted feed intake and livestock products, and also has threatened to the health of livestock by widening the range of sources of diseases. In order for livestock industry to confront climate change, new technology development for climate change adaptation and measures of greenhouse gas mitigation are essential. Agroforestry is the one of alternative measures to mitigate greenhouse gases and to adapt to climate change. Agroforestry is the way rearing livestock and cultivating plants in forest, which is suitable to Korea where mountain area is over 68%. Feedstock such as maize, soybean, rice, and grass grown by agroforestry would decrease feed cost. Agroforestry will decrease heat stress of livestock during hot weather and will be possible to pasture, which increases livestock welfare.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.932-938
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• 1997

Changes in viscosity and dynamic theological properties of Job's-tears were measured by Bohlin dynamic tester as a function of moisture, and measurement was performed within a linear viscoelastic range. The result of the shear stress vs shear rate of Job's-tears at different moisture contents $(50{\sim}75%)$ was applied to mathematical models and Herschel-Bulkley model showed the highest correlation coefficient. Lower moisture content (55%) produced higher yield stress and consistency index, but lower flow behavior index, whereas higher moisture content showed reverse effects. Job's-tears with $50{\sim}70%$ moisture contents showed a higher storage modulus (G') than loss modulus (G') at all frequencies, showing a higher concentrated polymer characteristics. However, higher moisture content (>75%) showed crossover point between G' and G', and frequency dependency. As the moisture content was increased, the amount of viscoelastic properties such as G', G', complex viscosity decreased during heating, and initial temperature and miximum value of viscoelastic properties shifted to higher temperatures, representing the moisture-dependence of Job's-tears upon theological properties.

• Journal of Families and Better Life
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• v.9 no.2
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• pp.137-153
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• 1991

The purpose of this study is to investigate the relationships between the homemaker's stress and their home management behavioral patterns in Money and Time focusing on the Morphogenic & Morphostatic. This research aimed to ' 1) Identify the overall tendency of homemaker's stress & home management behavioral patterns 2) Find out if socio-demographic variables(ie. age of homemakers, level of education, duration of marriage, umber of children, homemaker's employment, socioeconomic status) have significant effects on homemaker's stress and their home management behavioral patterns, 3)Identify the correlation between homemakers' stress and home management behavioral patterns. 4) Find out variables which have independently significant effect on home management behavioral patterns. For these purpose, this research conducted a survey by using questionnaire developed by former researchers. The subjects of this study are 500 homemakers living in Kwangju who have at least one child. The data analyzed occording to frequency, percentage, mean , one-way ANOVA, Duncan's multiple range test. Pearson's correlation and multiple regression. The main findings are as follows; 1) General tendency of the stress level percepted by the homemakers is relatively low 2) socio-demographic variables have significant effects on the stress of homemakers. Among them only homemaker's age. the number of children and socio-economic status have influe d on the stress of urban homemakers. In each area, there are differences among groups; homemaker's age, durations of marriage, number of children in the area of family; age, number of children, socio-economic status in th area of health; age. durations of marriage. number of children, socio-economic status in the area of finance; socio-economic status in the area of household work. 3) General tendency of homemakers behavioral patterns is some what morphostatic. 4)socio-demographic variables have significant effects on the behavioral patterns of home management, a)Homemaker's age, the level of education, socio-economic status is a variable to have influences on home management behavioral patterns of the Money. b)The age homemakers is a variable to have influences on home management behavioral patterns of the time. c)The age of homemakers, duration of marriage is a variable to have influences on the home management behavioral patters of the resources. 5)There are positive relationship between homemaker's stress and home management behavioral patterns . The higher level of stress , the more morphogenic home management behavioral patterns . 6)Influential variables related to management behavioral patterns are homemaker's age, the level of stress, socio-economic status.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.6
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• pp.149-154
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• 2022

Due to high power capabilities and high linearity of GaN devices, GaN Low-Noise Amplifiers (LNAs) without a limiter can be implemented in order to improve noise figure and reduce chip area in radar receivers. In this paper, a GaN LNA is presented for Ka-band radar receivers. The designed LNA was realized in a 150-nm GaN HEMT process and measurement results show that the voltage gain of >23 dB and the noise figure of <6.5 dB including packaging loss in the target frequency range. Under the high-power stress test, measured gain and noise figure of the GaN LNA is degraded after the first stress test, but no more degradation is observed under multiple stress tests. Through post-stress noise and s-parameter measurements, we verified that the GaN LNA is resilient to pulsed input power of ~40 dBm.

• Korean Journal of Materials Research
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• v.1 no.3
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• pp.125-131
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• 1991

Boron penetration phenomenon of $p^{+}$ silicon gate with as-deposited amorphous or polycrystalline Si upon high temperature annealing was investigated using high frequency C-V (Capacitance-Volt-age) analysis, CCST(Constant Current Stress Test), TEM(Transmission Electron Microscopy) and SIMS(Secondary Ion Mass Spectroscopy), C-V analysis showed that an as-deposited amorphous Si gate resulted in smaller positive shifts in flatband voltage compared wish a polycrystalline Si gate, thus giving 60-80 percent higher charge-to-breakdown of gate oxides. The reduced boron penetration of amorphous Si gate may be attributed to the fewer grain boundaries available for boron diffusion into the gate oxide and the shallower projected range of $BF_2$ implantation. The relation between electron trapping rate and flatband voltage shift was also discussed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.3
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• pp.548-554
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• 1994

The high temperature fatigue crack growth behavior of SUS 304 stainless steel at $550^{\circ}C$ and $650^{\circ}C$ was investigated under various kinds of stress ratio and frequency in sinusoidal waveform on the basis of the non-linear fracture mechanics. The result arranging crack growth rate by modified J-integral J' showed influence of stress ratio and frequency. All the data obtained under the test at $550^{\circ}C$ were plotted within data band of da/dN-${\triangle}J_f$ relationship for cycle-dependent crack growth. On the basis of static creep and cycle-dependent data band; both time- and cycle-dependent crack growth behavior was observed under loading conditions at $650^{\circ}C$, but cycle-dependent crack growth behavior predominantly appeared and time-dependent crack growth behaviour was little observed under loading conditions at $550^{\circ}C$. Fractographic examinations for fracture surface indicated that the fracture mode was generally transgranular. The stripes were found on fracture surface and each stripe was accompanied by a crack tip blunting and an abrupt increase in the load-point displacement. The $J'_{an}$ had a validity in case of $650^{\circ}C, but scarcely had it in case of $550^{\circ}C$.