• Magazine of the Korean Society of Agricultural Engineers
• /
• v.32 no.3
• /
• pp.31-38
• /
• 1990

The power water flowed out from the multipurpose darn influences the ecosystem approximately because of the low water temperature. An appropriate counter measure to the rising water temperature is needed for growing crops especially when the temperature is below 18˚C in the source of the irrigation water This observational study is practiced in Yong-Doo water warming canal and pond in the down stream of Choong-Ju multipurpose dam and is practiced for analyse and compare the rising effects in actural water temperature by actual measurement with the rising effects of planned water temperatuer by the basic theoritical method and for the help to present the direction in plan establishment through investigate the results afterwards. The results are as follows. 1.The degree of the rise of the water temperature can be decided by $\theta$x=$\theta$o +K L--v.h (T-$\theta$˚)Then, K values of a factor representing the characteristics of the water warming canal were 0.00002043 for the type I. and 0.0000173 for the type II. respectively. 2.A variation of water temperature which produced by the difference effective temperature and water temperature in the water warming canal was $\theta$x1 = 16.5 + 15.9(1-e -0.00018x), $\theta$x2 =18.8 + 8.4( 1-e -0.000298x)for the type I. and $\theta$x, = 19.6 + 12.8 ( 1-e -0.00041x) for the type II. 3.It was shown that the effects of the rise of water temperature for the type I. water warming canal were greater than that of type II. as a resultes of broadening the surface of the canal compared with the depth of water, coloring the surface of water canal and installing the resistance block. 4.In case of the type I. water warming canal, the equation between the air temperature and the degree of the rise of water temprature could be made ;Y= 0.4134X + 7.728 In addition, in case of the type II. water warming canal, the correlation was very low. 5.A monthly variation of the water temperature in the water warming canal was the highest in August during the irrigation period and the water temperature rose with the air temperature until August. However, it was blunted after then. 6.A rising degree of water temperature of the practical value in the water warming pond was higher than that of the theoritical equation by 69% for the type I. and 57% for the type II. Accordingly, it was possible to acquire the result near the practical value.$\theta$w-$\theta$o=[1-exp{ -h(1+2$\psi$) . X($\theta$w-$\theta$0)XC Here, C values are 1.69 for the type I. and 1.57 for the type II. 7.It was shown that the effect of the rise of water temperature was favorable when the thermal absorption was to be good by coloring the surface of the water warming pond and removing the bottom osmosis. 8.By enlarging the surface of water in comparison with the depth, and by having dead area of water in the water warming pond, this structure in the water warming pond is helpful for the rise of water temperature.

• Polymer(Korea)
• /
• v.25 no.3
• /
• pp.399-405
• /
• 2001

Poly[3-octylthiophene-co-3-(4-fluorophenyl)thiophene]s were synthesized in 2:1, 1:1, and 1:2 mole ratios, and organic electroluminescent devices were fabricated using the copolymers. The opto-electrical properties of the copolymers were studied by PL, EL spectra, I-V, and V-L curves of the organic electroluminescent devices in conjunction with the energy band diagrams which were obtained from the cyclic voltammogram and the electronic absorption spectra. The LUMO energy level of P(OT/FPT)(1:1) is the lowest as -3.35 eV. In the copolymers P(OT/FPT)(2:1) and P(OT/FPT)(1:1) the ${\lambada}_{max}$ in the PL and EL spectra red-shifted as the mole ratio of fluorophenyl group increased while in P(OT/FPT)(1:2) it showed a blue-shift. This indicates that the backbone chain is twisted due to the steric hinderance of the fluorophenyl group leading to shorter ${\pi}$-conjugation length. P(OT/FPT)(1:1) showed the highest EL intensity and the highest power efficiency among the three copolymers. In P(OT/FPT)(1:2) the roughness of the film surface causes unusually high local leakage current leading to the low efficiency of electroluminescence.

• Food Science and Preservation
• /
• v.23 no.2
• /
• pp.218-224
• /
• 2016

The quality and shelf life of noodles containing onion powder (0, 3, 5, and 10%) were investigated. The pH of raw noodles decreased by increasing the concentration of onion power. The weight, volume, and water absorption of the cooked noodles were comparable, irrespective of onion powder concentrations. Color L and a values of raw noodles decreased, while b value increased by addition of onion powder. However, no considerable differences in color values were observed among the control and onion noodle groups after cooking (p<0.05). The total polyphenol contents and DPPH radical scavenging activities of raw and cooked noodles increased with increasing onion powder concentrations, although the latter had lower values. In the aspect of texture, the control group showed higher hardness and chewness than those of noodle containing onion powder, except for springiness. The results of raw noodle storage at $10^{\circ}C$ for 12 days indicated that raw onion noodles, especially those with 5% onion powder added, could be preserved for at least 6 days longer than the control noodle. In the sensory evaluation of cooked noodles, no significant differences in appearance, taste, flavor, texture and overall acceptability were observed between the control and onion noodle groups. This study indicates that the addition of 5% onion powder could improve the functionality and shelf life of noodles.

• Journal of the Microelectronics and Packaging Society
• /
• v.17 no.2
• /
• pp.63-67
• /
• 2010

The organic solar cells with Glass/ITO/PEDOT:PSS/P3HT:PCBM/Al structure were fabricated using regioregular poly (3-hexylthiophene) (P3HT) polymer:(6,6)- phenyl $C_{61}$-butyric acid methyl ester (PCBM) fullerene polymer as the bulk hetero-junction layer. The P3HT and PCBM as the electron donor and acceptor materials were spin casted on the indium tin oxide (ITO) coated glass substrates. The optimum mixing concentration ratio of photovoltaic layer was found to be P3HT:PCBM = 4:4 in wt%, indicating that the short circuit current density ($J_{SC}$), open circuit voltage ($V_{OC}$), fill factor (FF) and power conversion efficiency (PCE) values were about 4.7 $mA/cm^2$, 0.48 V, 43.1% and 0.97%, respectively. To investigate the effects of the post annealing treatment, as prepared organic solar cells were post annealed at the treatment time range from 5min to 20min at $150^{\circ}C$. $J_{SC}$ and $V_{OC}$ increased with increasing the post annealing time from 5min to 15min, which may be originated from the improvement of the light absorption coefficient of P3HT and improved ohmic contact between photo voltaic layer and Al electrode. The maximum $J_{SC},\;V_{OC}$, FF and PCE values of organic solar cell, which was post annealed for 15min at $150^{\circ}C$, were found to be about 7.8 $mA/cm^2$, 0.55 V, 47% and 2.0%, respectively.

• Journal of the Korean Electrochemical Society
• /
• v.11 no.4
• /
• pp.256-261
• /
• 2008

In this study, Nafion membrane was modified to prevent methanol crossover by layer-by-layer self assembly using polyaniline (PANi) as a polycation and sulfonated poly(ether sulfone) (SPES) as a polyanion onto the Nafion surface. Since PANi and SPES possess thermal and chemical stability and rigid backbone, their layer-by-layer self-assembled films on the Nafion are expected to reduce methanol permeability and to increase mechanical stability. UV-Vis absorption spectroscopy verified a linear build-up of the multilayers of PANi and SPES. We found that the thickness per bilayer was about 10 nm by TEM measurement. Although modified Nafion membrane exhibited 15% decrease of proton conductivity, it reduceded 67% of methanol permeability compared to that of the pristine Nafion membrane, resulting in 2.5 times larger selectivity. At the performance test of the fuel cell using 5M methanol as a fuel, the modified Nafion membrane showed 2.4 times higher maximum power density at $30^{\circ}C$ and 1.4 times larger at $60^{\circ}C$ than the pristine Nafion.

• The Korean Journal of Food And Nutrition
• /
• v.29 no.1
• /
• pp.134-143
• /
• 2016

We evaluated the antioxidant properties of adzuki beans and the quality characteristics of sediment using various cultivation methods. There were significant differences in total polyphenol and flavonoid contents in beans grown using different methods of cultivation (p<0.05). Also, DPPH and ABTS radical-scavenging activities were significantly different depending on cultivation method (p<0.05). The sediment yield before drying of Chungju-pat, Hongeon, and Arari was 296.64~339.01, 271.36~282.24, and 268.21~292.32%, respectively, and the sediment yield after drying was 71.68~85.41, 77.90~85.19, and 74.15~78.65%, respectively. The L-value of Chungju-pat and Arari sediments revealed a significant difference given different cultivation methods (p<0.05), but Hongeon sediment did not show a significant difference. There was a significant difference in the a- and b-value of adzuki bean sediments cultivated using different methods (p<0.05). The particle size of Chungju-pat, Hongeon, and Arari sediments was 66.21~98.80, 61.62~97.07, and $82.96{\sim}106.71{\mu}m$, respectively, and all were significantly different depending on cultivation method (p<0.05). There were also significant differences in the water absorption index, water solubility index, and swelling power when different cultivation methods were used (p<0.05).

• Culinary science and hospitality research
• /
• v.19 no.2
• /
• pp.1-10
• /
• 2013

This study was conducted to investigate the quality characteristics of dumpling shells with white lotus leaf powder added to them (WLL 0%, 1%, 2%, 3%, 4%). Water binding capacity and moisture content of dumpling shells were not significantly different. Solubility in $50^{\circ}C$, $60^{\circ}C$ and $70^{\circ}C$ of dumpling dough has decreased because of the addition of WLL. Swelling power of all groups has increased because of increased amount of WLL content and temperature. The mass, volume and water absorption rate of cooked dumpling shells decreased while the turbidity of cooked dumpling shells increased with the addition of WLL. L and b value of dumpling shells significantly decreased and a value of dumpling shells significantly increased because of increased amount of WLL contents. Hardness and adhesiveness of dumpling shells significantly increased in WLL2 and WLL3 groups. Cohesiveness, springiness, gumminess and chewiness of cooked dumpling shells were not significantly different according to the additions of WLL. In sensory evaluation, color, flavor, white lotus leaf flavor, taste and overall acceptability significantly increased in WLL3. Stickiness, softness, chewiness of cooked dumpling shells were not significantly different according to the additions of WLL. Overall, the result of this study indicates that the dumpling shell containing 3% WLL powder was most preferred among the groups.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.40 no.8
• /
• pp.711-719
• /
• 2016

In this study, we derived an theoretical equation, using a simplified spring-mass model for the rolling stock, to obtain the overriding behavior of a leading vehicle, which is considered as the main factor in train accidents. To verify the derived equation, we created a simple 2D model based on the theoretical model, and a simple 3D model considering the characteristics of the power bogie. We then compared the theoretical results with the simulation results obtained using LS-DYNA. The maximum relative derivations in the vertical displacements at the first end-buffer, which is the most important point in overriding, were 3.5 [%] and 1.7 [%] between the two results. Further, we evaluated collision-induced overriding displacements using the theoretical equation for a rubber draft gear, a hydraulic buffer under various collision conditions. We have suggested a theoretical approach for the realization of overriding collision accidents or the energy absorption design of the front end of trains.

• Membrane Journal
• /
• v.30 no.3
• /
• pp.173-180
• /
• 2020

As the demand for fossil fuels continues to increase worldwide, carbon dioxide (CO₂) concentration in the air has increased over the centuries. The way to reduce CO₂ emissions to the atmosphere, carbon capture and sequestration (CCS) technology have been developed that can be applied to power plants and factories, which are primary emission sources. According to the climate change mitigation policy, direct air capture (DAC) in air, referred to as "negative emission" technology, has a low CO₂ concentration of 0.04%, so it is focused on adsorbent research, unlike conventional CCS technology. In the DAC field, chemical adsorbents using CO₂ absorption, solid absorbents, amine-functionalized materials, and ion exchange resins have been studied. Since the absorbent-based technology requires a high-temperature heat treatment process according to the absorbent regeneration, the membrane-based CO₂ capture system has a great potential Membrane-based system is also expected for indoor CO₂ ventilation systems and immediate CO₂ supply to smart farming systems. CO₂ capture efficiency should be improved through efficient process design and material performance improvement.

• Korean Journal of Materials Research
• /
• v.22 no.5
• /
• pp.259-273
• /
• 2012

Chalcogenide-based semiconductors, such as $CuInSe_2$, $CuGaSe_2$, Cu(In,Ga)$Se_2$ (CIGS), and CdTe have attracted considerable interest as efficient materials in thin film solar cells (TFSCs). Currently, CIGS and CdTe TFSCs have demonstrated the highest power conversion efficiency (PCE) of over 11% in module production. However, commercialized CIGS and CdTe TFSCs have some limitations due to the scarcity of In, Ga, and Te and the environmental issues associated with Cd and Se. Recently, kesterite CZTS, which is one of the In- and Ga- free absorber materials, has been attracted considerable attention as a new candidate for use as an absorber material in thin film solar cells. The CZTS-based absorber material has outstanding characteristics such as band gap energy of 1.0 eV to 1.5 eV, high absorption coefficient on the order of $10^4cm^{-1}$, and high theoretical conversion efficiency of 32.2% in thin film solar cells. Despite these promising characteristics, research into CZTS-based thin film solar cells is still incomprehensive and related reports are quite few compared to those for CIGS thin film solar cells, which show high efficiency of over 20%. The recent development of kesterite-based CZTS thin film solar cells is summarized in this work. The new challenges for enhanced performance in CZTS thin films are examined and prospective issues are addressed as well.