• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
• /
• 2003.10a
• /
• pp.51-70
• /
• 2003

In recent years, Korean rice must compete with the rice of advanced countries under Doha Development Agenda(DDA) and free Trade Agreement(FTA). Therefore we should find more active and positive solution in rice industry according to the inncreasing power of international pressure. Increasing rice production was the most important policy during the past food-deficient days, but recently, with overproduction of rice, various circulation system by the brand(price)-differentiation should be settled in a recent market of Korea. Nowadays, some advanced rice farmers and Rice Processing Complex(RPC) managers developed new brands of rice with high-quality, adding healthy materials and environment-friendly farming methods. Therefore, the future strategy of making a new brand rice should be planned including selection of rice variety, cultural and post-harvest techniques, circulation and processing methods to compete against foreign rice. And environment-friendly farming is also recommendable for food safety and differentiate from imported rice. For the purpose of successful brand-rice, the following points might be considered. Firstly, selection of good quality rice and continual development of good variety must be conducted for the differentiation of Korean rice from foreign rice. Secondly, a special contract between producer and consumer with functional-rice, organic filming-rice, specific-rice will be recommendable. Thirdly, improvement of post-harvest management and milling system are necessary for the production of differentiated-rice. Fortunately, standard of inspection, rules of description for brand-rice must be developed by a more scientific examination in order to settlement of trust for consumer. Finally, provincial or regional-representative brand rice must be settled and conducted for the development of agreement market system between producer and consumer.

• Proceedings of the KIEE Conference
• /
• 2000.07c
• /
• pp.1748-1750
• /
• 2000

There are currently considerable interests in the applications of conjugated polymers, oligomers. and small molecules for thin-film electronic devices. Organic materials have potential advantages to be utilized as semiconductors in field-effect transistors and light-emitting diodes. In this study we fabricated the devices based on pentacene as active layer. Octadecyltrichlorosilane (OTS) is used as buffer layer between $SiO_2$ and pentacene. Atomic force microscopy (AFM), X-ray diffraction (XRD), and electrical conductivity were used with OTS on $SiO_2$ 10nm which the pentacene layer was thermally evaporated in vacuum at a pressure of about $2.0\times10^{-6}$ Torr. In the result of AFM, the grain length is grown by using OTS for surface treatment. Electrical conductivity is changed from $3.19{\times}10^{-6}$ S/cm to $2.12{\times}10^{-7}$ S/cm. We observed that electrical conductivity is also increased by surface treatment. According to these results, the surface treated devices exhibited the increase to compared no treatment.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.21 no.6
• /
• pp.91-102
• /
• 2017

The early basic studies on RDE has been surveyed in the previous paper. Recently active researches are carrying on for the application to the power plant and aerospace propulsion systems. Collaboration researches are going on for the application of RDE for the gas turbine, liquid rocket and combined cycle engines in many countries. Following the previous Part 1 paper, present paper is intended to provide the comprehensive survey of recent worldwide efforts on the realistic application of RDE.

• Korean Medical Education Review
• /
• v.16 no.3
• /
• pp.132-140
• /
• 2014

Higher education is under unprecedented pressure for quality improvement and cost containment/reduction due to global competition and ever-increasing tuition costs. These twin challenges require an unconventional approach, and massive open online courses (MOOCs) and flipped learning have recently emerged as two promising educational alternatives not only to address the current problems but also to direct the future of education. This paper discusses the rapidly changing environment for education, MOOCs, and flipped learning as learning alternatives, the relationship between MOOCs and flipped learning, and course redesign for the implementation of flipped learning. The case of Ulsan National Institute of Science and Technology (UNIST) is also discussed for benchmarking purposes since it has been pioneering an innovative educational methodology for teaching and learning IT-enabled active learning methods from its inception in 2009. It has redesigned almost 70 courses (20% of all the courses to offer) for flipped learning. The objectives of UNIST's educational experiment are three-fold: improving the quality of education for students, improving teaching productivity for the faculty, and containing/reducing education costs for the university.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.33 no.1
• /
• pp.60-68
• /
• 2009

The steam reformer for hydrogen production from methane is studied by a numerical method. Langmuir- Hinshelwood model is incorporated for catalytic surface reactions, and the pseudo-homogeneous model is used to take into account local equilibrium phenomena between a catalyst and bulk gas. Dominant chemical reactions are Steam Reforming (SR) reaction, Water-Gas Shift (WGS) reaction, and Direct Steam Reforming (DSR) reaction. The numerical results are validated with experimental results at the same operating conditions. Using the validated code, parametric study has been numerically performed in view of the steam reformer performance. As increasing a wall temperature, the fuel conversion increases due to the high heat transfer rate. When Steam to Carbon Ratio (SCR) increases, the concentration of carbon monoxide decreases since WGS reaction becomes more active. When increasing Gas Hourly Space Velocity (GHSV), the fuel conversion decreases due to the heat transfer limitation and the low residence time. The reactor shape effects are also investigated. The length and radius of cylindrical reactors are changed at the same catalyst volume. The longer steam reformer is, the better steam reformer performs. However, system energy efficiency decreases due to the large pressure drop.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.7 no.4
• /
• pp.622-632
• /
• 1995

The present numerical study is aimed to investigate time-dependent characteristics of a two-dimensional lid-driven square cavity flow of three high Reynolds numbers, $7.5{\times}10^3$, $10^4$ and $3{\times}10^4$. A conservative convection term on irregular grids was adopted by renewing the MAC type difference schemes on regular grids. Relaxation of velocity and pressure is implemented by SOLA algorithm. In case of $Re=7.5{\times}10^3$, flow behavior converges to steady state after a transient period. But for $Re=10^4$, periodic unsteady sinusoidal fluctuation of local velocity and kinetic energy is found and continuous movements of small eddies in the secondary flow regions are also discovered. Random generation of eddies and their active migrating behavior are detected for $Re=3{\times}10^4$, resulting in complete unsteady and non-linear flow characteristics. And, an organized structure similar to a Moffat vortex is also observed from the time-mean flow patterns. Furthermore, a typoon-like vortex(TLV) appears intemittently and rotates along the separation regions and boundary layers.

• Journal of Ginseng Research
• /
• v.42 no.3
• /
• pp.356-360
• /
• 2018

The fermentation of medicinal herbs facilitated by microbes is assumed to exert promising therapeutic efficacy on the absorption, bioavailability, and pharmacological effects by speeding up the making or conversion of active constituents into their metabolites. We examined the cardioprotective potential of fermented ginseng, GBCK25, against high-fat diet (HFD)-induced metabolic and functional illnesses as following the essential analysis such as electrocardiographic parameters, alterations of body and organ weights, and echocardiographic studies. The results exhibited that body weights were significantly reduced and the gain of different organ weights were partly eased by GBCK25 treatment. Echocardiography results proposed the amelioration of heart function through normalized levels of left ventricle systolic pressure, ejection fraction, and fractional shortening. These outcomes deliver straight confirmation that GBCK25 could be a potential nutraceutical source for the relief of HFD-induced obesity mediated cardiac dysfunctions.

• YAKHAK HOEJI
• /
• v.29 no.4
• /
• pp.165-175
• /
• 1985

It has been reported that clonidine is $\alpha_2$-adrenergic agonist, potnet new hypotensive drug in human with low dose. The change in blood pressure is implicated in the concentration, release, uptake and metabalism of catecholamine and activity of catecholamine synthesizing enzyme in specific brain areas. Thus the experiment was set up to investigate the effect on the enzyme activity of clonidine alone and that of clonidine pretreated with imipramine or tranylcypromine by measuring activity of the Dopa-forming enzyme, tyrosine hydroxylase (TH) and epinephrine forming enzyme, phenylethanolamine-N-methyl transferase (PNMT) in brain and adrenal gland. The TH activity in brainstem and substantia nigra is decreased by intraperitoneally administered clonidine 0.1mg/kg twice a day for 5 days, but increased in the rats pretreated with imipramine 10mg/kg intraperitoneally given 26 hrs and 5 hrs before decaptitation. However the TH activity in all regions of brain is increased in rats pretreated with tranylcypromine 10mg/kg intraperitoneally twice a day for 5 days. The effect of clonidine on TH activity is due to inhibition release of norepinephrine by activation of presynaptic $\alpha_2$-adrenoreceptor, axon terminal result in the decrease of TH activity in brain. The increasing of TH activity in brain results in attenuation of the role of clonidine by pretreated with imipramine or tranylcypromine in rats. The activity of PNMT was not significantly affected by clonidine, imipramine and tranylcypromine in adrenal gland.

• Journal of ILASS-Korea
• /
• v.16 no.3
• /
• pp.126-133
• /
• 2011

In HCCI Engine, combustion is affected by change of compression speed corresponding to engine speed. The purpose of this study is to investigate the mechanism of influence of engine speed on HCCI combustion characteristics by using numerical analysis. At first, the influence of engine speed was shown. And then, in order to clarify the mechanism of influence of engine speed, results of kinetics computations were analyzed to investigate the elementary reaction path for heat release at transient temperatures by using contribution matrix. In results, as engine speed increased, in-cylinder gas temperature and pressure at ignition start increased. And ignition start timing was retarded and combustion duration was lengthened on crank angle basis. On time basis, ignition start timing was advanced and combustion duration was shortened. High engine speed showed higher robustness to change of initial temperature than low engine speed. Because of its high robustness, selecting high engine speed was efficient for keeping stable operation in real engine which include variation of initial temperature by various factors. The variation of engine speed did not change the reaction path. But, as engine speed increased, the temperature that each elementary reaction would be active became high and reaction speed quicken. Rising the in-cylinder gas temperature of combustion start was caused by these gaps of temperature.

• Journal of Radiation Protection and Research
• /
• v.31 no.3
• /
• pp.149-153
• /
• 2006

An ionization chamber is still widely used in many fields by virtue of its' simple operational characteristics and the possibility of its' various shapes. A parallel type of an ionization chamber for a steel sheet thickness measurement was designed and fabricated. High pure xenon gas, which was pressurized up to 6 atm, was chosen as a filling gas to increase the current response and sensitivity for a radiation. A high pressure gas system was also constructed. The active volume and the incident window size of the fabricated ionization chamber were $30\;cm^3\;and\;12\;cm^2$, respectively. Preliminary tests with a 25 mCi $^{241}Am$ gamma-ray source and evaluation tests in a standard X-ray field were performed. The optimal operation voltage was set from the results of the collection efficiency calculation by using an experimental two-voltage method. Linearity for a variation of the steel sheet thickness, which is the most important factor for an application during a steel sheet thickness measurement, was 0.989 in this study.