• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.3
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• pp.508-512
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• 1998

The NTC thermistors were sintered by using microwave hybrid heating method at $1100^{\circ}C$~$1300^{\circ}C$ and those electrical properties were investigated. The obtained $B_{25^{\circ}C/85^{\circ}C}$ values from temperature dependence of electrical resisitivity were around 3100~3200 K which were almost the same values as conventionally sintered ones. Compared with conventional sintering process, this process could complete whole sintering process within 20 minutes. This the processing time and energy consumption could be reduced through this rapid heating by using microwave hybrid heating.t there were showed only two peaks, glycolide melting peak and lower molecular weight melting peak without lauryl alcohol. Conversion increased slowly with the reaction time up to 50 minutes, and then gave a sudden increase above that. The reaction time to disappear in glycolide melting peak during polymerization was shortened with the increase of lauryl alcohol content. Zero-shear viscosity of polyglycolic acid decreased with the increase of free acid content in glycolide.ssional energy and bending hysteresis increased. \circled3 Surface characteristics such as friction coefficient and thickness variation of highly shrinkage fabrics became relatively roughened state. \circled4 Since stiffened and roughened characteristics of highly shrinkage fabrics, drapabilities of them were significantly lowered. Additionally thermal insulation property of high shrinkage fabric was higher than that of low shrinkage fabric due to bulky and thickened feature. From the results, it is considered that the silk fabrics with high filling shrinkage have the good bulkiness and heat keeping properties and thus they have the suitable characteristics for high quality men's and women's formal garments.

• Journal of Radiation Protection and Research
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• v.16 no.1
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• pp.1-13
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• 1991

Effective dose equivalents resulting from inhalation of indoor radon-222 daughters at 12 residential areas in Korea were assessed by a simple mathematical lung dosimetry model based on the measurements of long-term averaged radon concentrations at 340 dwellings. The long-term averaged indoor radon-222 concentrations and corresponding eqilibrium equivalent radon $concentration(EEC_{Rn})$ measured by passive time-integrating CR-39 radon cups are in the range of $33.82{\sim}61.42Bq/m^3(median\;:\;48.90Bq/m^3)$ and of $13.53{\sim}24.57Bq/m^3(median\;:\;19.55Bq/m^3)$, respectively. The effective dose equvalent conversion factor for the exposure to unit $EEC_{Rn}$ derived in this study was estimated $1.07{\times}10^{-5}mSv/Bq\;h\;m^{-3}$ for a reference adult and agreed well with those recommended by the ICRP and UNSCEAR. The annual average dose equivalent to the lung $(H_{LUNG})$ from inhalation exposure to measured $EEC_{Rn}$ was estimated to be 20.90 mSv and resulting effective dose $equivalent(H_E)$ was to be 1.25 mSv, which is about 50% of the natural radiation exposure of 2.40 mSv/y to the public reported by the UNSCEAR.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.11
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• pp.1510-1518
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• 2010

The study was conducted to evaluate the effect of lighting schedule and nutrient density on growth performance, carcass traits and meat quality of broiler chickens. A total of 576 day old Arbor Acre male chickens was used with a $4{\times}2$ factorial arrangement. The four lighting schedules were continuous (23 L:1 D, CL), 20 L:4 D (12 L:2 D:8 L:2 D), 16 L:8 D (12 L:3 D:2 L:3 D: 2 L:2 D) and 12 L:12 D (9 L:3 D:1 L:3 D:1 L:3 D:1 L:3 D) and provided by incandescent bulbs. The two nutrient densities were high (H, starter diet: 13.39 MJ/kg apparent metabolisable energy (AME), 23.00% crude protein (CP); finisher diet: 13.39 MJ AME/kg, 19.70% CP) and low energy and protein level (L, starter diet: 12.03 MJ AME/kg, 20.80% CP; finisher diet: 12.14 MJ AME/kg, 18.30% CP). Houses with dark curtains and solid sidewalls were used. Chickens were randomly allocated to the 8 treatments with each treatment comprising 6 replicates of 12 chickens. Feed and water were available ad libitum. Lighting schedules showed no difference (p>0.05) in growth performance at the end of the experiment. 12 L:12 D significantly reduced (p<0.05) the concentration of malondialdehyde (MDA) compared to 23 L:1 D treatment. Intermittent lighting (IL) schedules produced higher protein content (p<0.001) in breast meat. Birds on high density diets had higher body weight (BW), feed intake (FI) (p<0.001), and feed conversion ratio (FCR) (p<0.001) throughout the experiment with the exception of 36 to 42 d. High nutrient density increased (p<0.05) abdominal fat, decreased (p<0.05) the moisture loss of meat, and reduced percentage of wings and legs. There was a significant lighting schedule${\times}$diet interaction (p<0.001) on FCR for days 8 to 14 and 15 to 21. Results indicated that IL can give similar growth performance in comparison with CL, meanwhile with positive effects on meat quality by increasing protein content and decreasing the concentration of MDA. High nutrient density resulted in greater growth performance.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.9
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• pp.1233-1242
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• 2011

The in vivo digestibility of mulberry leaves (Morus alba) and the effects of the partial replacement of cotton seed with fresh mulberry leaf in rations on the performance of growing Vietnamese cattle was investigated. For the in vivo digestibility trial, twenty castrated rams of Phanrang breed (a local prolific breed) with an initial weight of 23-25 kg, were first assigned to four groups according to weight and then randomly assigned to one of four dietary treatments to determine digestibility of nutrients in mulberry leaves (M. alba), natural Bermuda grass (Cynodon dactylon), elephant grass (Pennisetum purpureum) and buffalo grass (Panicum maximum cv. TD 58). All forages were cut and chopped daily before being offered (at 120% maintenance) to the sheep. In the feeding trial, 20 Laisind (Vietnam yellow cows${\times}$Red Sindhy bulls) crossbred bulls averaged 18 month old and 184 kg were used to investigate the effect of partial replacement of cottonseed in the diet by mulberry leaves on live weight gain and feed conversion rate. The experiment was a randomized complete block design with four levels of fresh mulberry leaves which varied from 0 to 15% of total dietary dry mater and five animals per treatment over an 84 day period. The in vivo digestion trial showed the superior quality of mulberry leaves compared with the grasses. Chemical analysis indicated that mulberry leaves had the highest CP and the lowest NDF contents (22.3 and 31.1% DM, respectively) among the four forages tested. Digestibility of DM and OM of the mulberry leaf (66.4 and 71.8%, respectively) was also the highest but that of CP (58.2%) and NDF (58.4%) was the lowest of the four forages evaluated (p<0.05). Consequently, the ME value and therefore net energy (NE) and unit feed for lactation (UFL) values of the mulberry leaves, which was estimated from chemical composition and digestibility values, were the highest among the forages investigated in the present study. Results of the feeding trial showed no treatment effect on average daily gain (ADG) of the cattle. The values were 554, 583, 565 and 568 g/d for animals in the diets of 0, 5, 10, and 15% mulberry leaves inclusion, respectively. Total DM intake of the animal was not affected by the treatment when expressed as kg/animal/d. However, when adjusted for metabolic weight of the animal the DM intake was reduced (p<0.05) as whole cottonseed was replaced by mulberry leaves in the ration. When the level of mulberry leaves in the ration increased from 5 to 15% of dietary DM at the expense of whole cottonseed, CP and ME intakes of the cattle were significantly decreased (p<0.05) and the feed to gain ratio reduced by 8 to 14% as compared with the control diet (p<0.05). Mulberry leaf is a good feed ingredient for ruminants because of its high level of crude protein and high digestibility of nutrients and energy. Mulberry leaves can be efficiently used as a source of protein supplement to replace cottonseed, a more expensive animal feeds ingredient, in the diet for Vietnamese cattle.

• Journal of Aquaculture
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• v.15 no.1
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• pp.15-21
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• 2002

Two groups of juvenile flounders (90 g/each) were fed on moist pellet feed thrice a day for a period of 8 weeks; the first group, reared in 4 circular (6m $\times$ 0.8 m) tanks (1200 flounders/tank), was fed daily (ED) and the second one on alternate days (EO). There was no significant difference in growth and feed conversion ratio (FCR) between these groups. There was also no difference in chemical composition, except in lipid, which was significantly higher (4.1%) in the ED group than the EO group (3.4%). Food intake and gain in the whole body nitrogen (N) were higher in the ED group but there was no significant difference between these groups in N retention; they excreted almost equal amount (114 vs 112 g) of N. Although phosphorus intake was significantly different between these groups, the flounders retained equal amount (0.5 g) of P in their body and excreted also equal amount (27.6 vs 26.0 g/kg weight gain) of p. Energy intake (2528 kJ) of the ED group was higher than that (2116 kJ) of the EO group. However, there was no significant difference in their energy retention efficiency. Clearly, alternate day feeding regimen led to more efficient utilization of food by the juvenile flounder.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.2
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• pp.171-181
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• 2011

Recently, many studies have been attempted to save the cost of production and to build the ocean energy power generating system. The low-reflection structure with the wall-typed curtain which has a wave power generation system of OWC is known as the most effective energy conversion system. A three-dimensional numerical model was used to understand the characteristics of velocity of flows about compressed air and to estimate the pressure acting on the low-reflection structure due to the short-period waves. The three-dimensional numerical wave flume which is the model for the immiscible two-phase flow was applied in interpretation for this. The numerical simulation showed well about the changes in velocity of compressed air and the characteristics of pressure according to the change in the wave height and depth of the curtain wall. Additionally, the results found that there was the point of the maximum velocity of the compressed air when the reflection coefficient is at its lowest point.

• The Journal of the Korea Contents Association
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• v.17 no.4
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• pp.1-11
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• 2017

Interest in all kinds of renewable energies has been highly increased while the micro-small-hydro power(MSHP) development has shown relatively slowly growth because of the negative public recognition about dam site development. It is, however, announced that the micro-SHP shows higher energy conversion efficiency compared to other renewable energies and does not emit any carbon dioxide. Thus, it is concerned about the development and application of micro-SHP as an alternative energy. In this study, the application for Android was exploited with Eclipse to visualize readily the potential realizable amount of hydropower by micro-SHP. With this application, we can select the region from the map, obtain the design discharge of the selected site was calculated with HEC-HMS, presented by U.S. Army of Corp. and perform the simply economic analysis in sequence. Yeongwol in Gangwon-do Province, Korea was chosen as the target area since historically abundant precipitation was found and it is possible to obtain fundamental data from WAMIS. Results from this study could be expanded the whole region of Korea. Also, the initial investment cost would be reduced if the location for micro-SHP would be determined properly, because this application can help us easily select and examine the potential micro-SHP sites without on-the-spot visit.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.371-377
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• 2009

The objectives of the present study were to investigate the effects of different dietary ratios of whole-crop corn silage and alfalfa hay on nitrogen (N) digestion, duodenal flow and metabolism across the portal-drained viscera (PDV) of growing beef steers, and to elucidate their relationships. Four steers (236${\pm}$7 kg BW) fitted with duodenal cannulae and chronic indwelling catheters into the portal and mesenteric veins and abdominal aorta were used in a 4${\times}$4 Latin square design. Animals were fed (at 12-h intervals) the 4 diets consisting of whole-crop corn silage (C) and alfalfa hay (A) in 80:20 (C8A2), 60:40 (C6A4), 40:60 (C4A6) and 20:80 (C2A8) ratios of which dietary crude protein (CP) was 10.5, 12.0, 13.5 and 15.0% of dry matter (DM), respectively. Feeding level was restricted to 95% of ad libitum intake to measure N digestion, blood flow and net flux of N across the PDV. Digestibility of DM and neutral detergent fiber and digestible energy intake linearly increased as the ratio of alfalfa hay increased. The N intake, duodenal flow and intestinal disappearance increased linearly with increasing alfalfa hay. Arterial and portal concentrations of ${\alpha}$-amino N showed a quadratic response to increasing levels of alfalfa hay and were the highest in steers fed the C6A4 diet. The net PDV release of ${\alpha}$-amino N and ammonia N increased linearly with increasing alfalfa hay, but urea N uptake by PDV did not differ among diets. As a percentage of apparently digested N in the total gut, net PDV release of ${\alpha}$-amino N linearly decreased from 66 to 48% with increasing alfalfa hay. Conversely, net PDV recovery of ${\alpha}$-amino N to intestinal N disappearance varied with increasing alfalfa hay accounting for 49, 50, 58 and 61% on C8A2, C6A4, C4A6 and C2A8 diets, respectively. Net PDV uptake of urea N, relative to apparently digested N, linearly decreased from 81 to 25% as alfalfa hay increased from 20 to 80% of DM intake. Considering PDV uptake of urea N, microbial efficiency and conversion of total tract digested N to PDV ${\alpha}$-amino N net supply, a diet consisting of 80% whole-crop corn silage and 20% alfalfa hay (10.5% CP) was the best, while considering the quantities of intestinal N disappearance and ${\alpha}$-amino N absorption, a diet of 20% whole-crop corn silage and 80% alfalfa hay (15% CP) would be preferred. The proportion of ${\alpha}$-amino N recovered by PDV relative to the intestinal N disappearance may vary with energy intake level of mixed forage diets.

• Journal of Korea Foresty Energy
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• v.24 no.1
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• pp.39-46
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• 2005

In this study, the possibility of sugar conversion of poplar wood(Populus $alba{\times}rglandulosa$) and their degradation features of major wood components were characterized using flow type supercritical water treatment system. The finely ground poplar wood meals were treated for 2min. under subcritical condition$(23MPa,\;275^{\circ}C\;and\;325^{\circ}C)$ and supercritical condition $(23MPa,\;375^{\circ}C\;and\;415^{\circ}C)$. respectively. The degradation products of poplar wood meals appeared brownish colors, including undegraded solids. Increasing the temperature of the system, the degradation rate of poplar wood meals was accelerated and reached up to $94\%\;at\;375^{\circ}C$. The total amount of reducing sugars in degradation products determined by DNS method were gradually lowered when the temperature condition became severe. This indicated that the reducing sugars formed were further degraded to kan derivatives by certain side reaction such as pyrolysis under higher temperature. In order to characterize degradation features of lignin, the degradation products were extracted with ethylacetate and the organic phases were subjected to GC-MS analysis. Main lignin degradation products were identified to vanillin, guaiacol, syrinaldehyde, 4-prophenyl syringol and dihydrosinapyl alcohol, which could be formed by the cleavage of ether linkages in lignin polymers by high temperature condition.

• Clean Technology
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• v.23 no.1
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• pp.54-63
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• 2017

Volatile organic compounds (VOCs) are widely used in both industrial and domestic activities. VOCs are one of the most unpleasant, frequently complaint-rousing factors of pollution around the world. It is now necessary to research and develop an alternative technology that could overcome the problems of the existing odor-control and VOC-eliminating techniques. In this study, essential oil and photocatalytic process was applied in the removal of benzene and toluene, typical VOCs in petrochemistry plant. therefore, this study conducted experiments on the selection of appropriate essential oil, photodegradation, hydroxyl radical generation capacity. The removal efficiency and reaction rate were performed to selecte the type and concentration of essential oil. As a result, removal efficiency of Hinoki Cypress oil was approximately 70% and reaction rate of Hinoki Cypress was high. The results of photolysis experiment, photocatalytic oxidation process showed that the decomposition efficiency of VOCs increased considerably with increasing UV lamp power. In addition, the conversion of VOCs was increased up to $0.1gL^{-1}$ photocatalysts. The hydroxyl radicals measure was performed to determine the ability to generate hydroxyl radicals. The analytical result showed that high $TiO_2$ concentration and lamp power was produced many hydroxyl radical. Experiments of the removal efficiency and reaction rate were performed using essential oil and photooxidation. As a result, the removal efficiency showed that the removal efficiency was increased high temperature and reaction time. The activation energy was calculated from the reaction rate equation at various temperature condition. Activation energy was approximately $18kJmol^{-1}$.