• Asian-Australasian Journal of Animal Sciences
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• v.30 no.4
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• pp.514-522
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• 2017

Objective: The study aimed to assess the N use efficiency (NUE) of pig slurry (in comparison with chemical fertilizer) for each regrowth yield and annual herbage production and their nutritive value. Methods: Consecutive field experiments were separately performed using a single application with a full dose of N (200 kg N/ha) in 2014 and by four split applications in 2015 in different sites. The experiment consisted of three treatments: i) control plots that received no additional N, ii) chemical fertilizer-N as urea, and iii) pig-slurry-N with five replicates. Results: The effect of N fertilization on herbage yield, N recovery in herbage, residual inorganic N in soil, and crude protein were significantly positive. When comparing the NUE between the two N sources (urea and pig slurry), pig slurry was significantly less effective for the earlier two regrowth periods, as shown by lower regrowth dry matter (DM) yield, N amount recovered in herbage, and inorganic N availability in soil at the 1st and 2nd cut compared to those of urea-applied plots. However, the effect of split application of the two N sources was significantly positive at the last two regrowth periods (at the 3rd and 4th cut). The two N sources and/or split application had little or no influence on neutral detergent fiber (NDF) content, acid detergent fiber (ADF) content, and in vitro DM digestibility, whereas cutting date was a large source of variation for these variables, resulting in a significant increase in in vitro DM digestibility for the last two regrowth periods when an increase in NDF and ADF content occurred. Split application of N reduced the N loss via nitrate leaching by 36% on average for the two N sources compared to a single application. Conclusion: The pig slurry-N was utilized as efficiently as urea-N for annual herbage yield, with a significant increase in NUE especially for the latter regrowth periods.

• KSBB Journal
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• v.9 no.5
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• pp.483-491
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• 1994

It is known that a key limiting factor to the use of ultrafiltration membranes is that of membrane fouling, which has been a major cause of permeate flux reduction. In this work, the effects of several factors (operating time, protein concentration, temperature and pH, etc.) influencing permeate flux during ultrafiltration of gelatin, casein and bovine serum albumin using a hollow fiber membrane(M. W. 10,000 cut off) reactor have been examined. The permeate flux of gelatin solution was maintained almost constant during the operation up to 6 hours, but those of casein and albumin solutions were decreased to 50% and 43% of initial value after an operation time of 60min. The permeate flux with increasing concentration and temperature of protein solutions increased, but the permeate flux showed a minimum value near the isoelectric point of proteins. The permeate fluxes of protein solution were enhanced by a temperature increase and pH control. Also, it is proposed that fouling can be decreased by the pretreatment of insoluble proteins with enzymes.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.4
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• pp.43-52
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• 2020

As the membrane gas separation technology grows, various models were developed by numerous researchers to describe the separation process. In this work, the counter-current model was compared thoroughly with experimental data. Experimentally, hollow fiber membrane using CA module was prepared for the separation of biogas. The pure gas permeation properties of membrane module for methane, nitrogen, oxygen, and carbon dioxide were measured. The permeance of CO2 and CH4 were 25.82 GPU and 0.65 GPU, respectively. The high CO2/CH4 selectivity of 39.7 was obtained. the separation test for three different simulated mixed gases were carried out after pure gas test, and the gas concentration of the permeate at various stage-cut were measured from CA membrane module. Results showed that the experimental data agreed with the numerical simulation. A mathematical model has implemented in this study for the separation of biogas using a membrane module. The finite difference method (FDM) is applied to calculate the membrane biogas separation behaviors. Futhermore, the counter-current model can be considered as a convenient model for biogas separation process.

• Membrane Journal
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• v.33 no.6
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• pp.352-361
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• 2023

Steam methane reforming is currently the most widely used technology for producing hydrogen, a clean fuel. Hydrogen produced by steam methane reforming contains impurities such as carbon monoxide, and it is essential to undergo an appropriate post-purification step for commercial usage, such as fuel cells. Recently, membrane separation technology has been gaining great attention as an effective purification method; in this study, we evaluated the feasibility of using commercial polysulfone membranes for biogas upgrading to separate and recover hydrogen from a hydrogen/carbon monoxide gas mixture. Initially, we examined the physicochemical properties of the commercial membrane used. We then conducted performance evaluations of the commercial membrane module under various conditions using mixed gas, considering factors such as stage-cut and operating pressure. Finally, based on the evaluation results, we carried out simulations for process design. The maximum H₂ permeability and H₂/CO separation factor for the commercial membrane process were recorded at 361 GPU and 20.6, respectively. Additionally, the CO removal efficiency reached up to 94%, and the produced hydrogen concentration achieved a maximum of 99.1%.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.1 s.53
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• pp.69-77
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• 2009

An underwater structure is made to put with serious damage state by special environmental factors. If this damage phenomena persist, as for the structure, it is generated a structural serious problem because of the corrosion of a reinforcing bar and the loss of the concrete cut end. Repair work of an underwater structure is very harder than repair work in land, and it is actual that certification about a maintenance effect is uncertain. And the existing repair method is applied to a structure damaged with you without verification of a repair effect by a foreign reward and experience. In this study, a repair method about an underwater structure was proposed and observed a behavior characteristic and interface failure of an specimens. and comparison analyzed an effect of a proposed maintenance method.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.41-57
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• 1997

The present study investigated the effects of hyperbaric oxygen therapy on periodontal wound healing of replanted rat tooth. 80 rats (Sprague-Dawley strain) weighting $130{\pm}5gm$ were selected and divided into experimental and control group, each group consisting of 40 rats. Rats were administered 0.4% ${\beta}$-aminoproprionitrile for 5 days to achieve gentle tooth extraction. The maxillary first molars were extracted under anesthesia with pentobarbital, washed in sterile distilled water, treated with bacterial collagenase to remove collagen fibers on the root surfaces. After washing in water overnight, the mesial root surface were demineralized by application of citric acid, washed, dried and stored at $4^{\circ}C$. Immediately after tooth extraction and bleeding control, the treated molars extracted previously from other rats were replanted. The experimental group was exposed to hyperbaric oxygen at 2.5 atm. for 2 hrs. a day during experimental period. Eight animals of each group were sacrificed 1, 3, 6, 8, 10 days after reimplantation of teeth by intracardiac perfusion with 4% paraformaldehyde. The replanted molars and surrounding tissues were cut, demineralized, dehydrated and embedded in paraffin. Sections were stained with azan, toluidine blue and hematoxylin. Some other sections were stained by means of immunostaining achieved by the avidinbiotin complex method. The results as follows; 1. Experimental group showed fast healing of gingival epithelium. 2. Macrophage and newly formed blood vessels appeared early in the gingival connective tissue of experimental group. 3. Experimental group showed fast, abundant fibroblast proliferation and regularity of collagen fiber. 4. In both group, collagen was distributed along the collagen fiber. The distribution was strong and regular in the experimental group. 5. In the regenerated periodontal ligament of experimental group, fibers showed regular arrangement and invaded root surface fast.

• Journal of the Korean Wood Science and Technology
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• v.17 no.2
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• pp.1-12
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• 1989

To study the structure of opposite wood in the angiosperms. samples were cut from stems and branchs of 10 spcies growing in Korea. The opposite side was defined as being along a line passing from the most wide annual ring of the tension wood on the upper side to the pith and extrapolated through the opposite side. lateral sides being on the right and left of this line. The stem woods growing almost horizontally were surveyed the structural features of the well-developed opposite wood for the tension wood. In the annual-ring of the well-developed opposite woods. an investigation was made on how the dimension of elements, microfibril angles. and cell wall layers change from tension side to opposite side. The structural characteristics of opposite wood in hardwoods realized in this study are as follows: 1. The vessel diameters increased continuously to ward the opposite side in which the values were maximum. The vessel length also increased toward opposite side. but the rates of increase were smaller than those in the vessel diameters. 2. The wood fiber length were decreased from tension toward opposite side. but the rates of decrement were f1actuated within the sampled species. 3. The microfibril angles had the minimum values on the tension side. then increased steeply toward the opposite side in which the values maximum. 4. In the percentage of elements the vessel elements increased continously at a relative rate from the tension to opposite side, whereas the values of the wood fibers were lower in the opposite than the tension side, but the' variation patterns of rays were not seem distinctly. 5. The component layers of the wood fiber in the opposite woods were very similar to the lateral woods.

• Composites Research
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• v.18 no.1
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• pp.38-44
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• 2005

In this paper, the group velocity dispersion curves of the $S_o$ symmetric mode in unidirectional CFRP plate was calculated as varying the propagating direction. The group velocity curve was obtained with the group velocities of the $S_o$ symmetric mode corresponding to 0.2 MHz-mm under the first cut-off frequency in the dispersion curves, and corrected by introducing the slowness curve. The velocities of the $S_o$ symmetric mode in the unidirectional CFRP plate were measured as varying the propagating direction and compared with the col?rotted group velocity curve. The measured velocities were good agreement with the corrected group velocity curve except near the fiber direction which was called the cusp region. It implies that the direction of the group velocities incline toward the fiber direction of the unidirectional CFRP plates when the propagation direction is not accorded with the principal axis. It is supposed that this phenomenon rerults from the preferential propagating the energy toward the direction with the faster propagation velocity.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.2
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• pp.206-213
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• 2011

An experiment was conducted to evaluate the effect of replacing barley and soybean meal in finishing diets with sesame hull (SH) on growth performance, digestibility, and carcass characteristics of Black goat kids. Twenty-one Black goat kids were assigned randomly to 0%, 10%, or 20% SH diets (7/diet). The study lasted for 63 d. Intakes of dry matter (DM), organic matter (OM), and crude protein (CP) of kids fed the 10% diet were greater (p<0.05) than for the 0% and 20% SH diets (p<0.10). Neutral detergent fiber (NDF) and acid detergent fiber (ADF) intakes were highest (p<0.05) for kids fed the 10% SH diet when compared to 0% and 20% SH diets. Ether extract (EE) intake was greater (p<0.05) for kids fed 10% and 20% SH diets when compared to 0% SH. Digestibilities of DM, OM, CP, NDF, and ADF were similar among all diets. However, sesame hull inclusion increased (p<0.05) EE digestibility. Final body weight, total gain, average daily gain (ADG), and feed conversion ratio were comparable among all diets. Cost of gain was lower (p<0.05) in kids fed 20% SH than the 0% SH diet, while there was no difference between the 10% SH diet and the other two diets. Dressing percentage, hot and cold carcass weights, non-carcass components, carcass cut weights, and meat quality parameters were not influenced by SH. Total fat percentage in the leg was greater (p<0.05) on 0% SH than on the 10% SH diet. Results of this study demonstrated that inclusion of sesame hull at levels of 10 or 20% did not influence the performance of Black goat kids, but the cost of gain was lower.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1668-1670
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• 2002

Since more than two decades, the conventional PD detecting systems have been employed in order to detect the partial discharges occurring inside the HV power apparatus for their diagnosis by use of different type of detection such as acoustic and UHF detection method. Regardless of their wide on-site application, a certain number of technical inconveniences have been disclosed as follows : multistage amplification. large volume, susceptible to external noise and high price. In this respect, the optical measurement techniques are widely proposed in these days in this concerned field ascribed to the following advantages : immune to external EMI noise and broad band response of the Pockels cell covering from DC to GHz. However, the reliability of several proposed techniques enabling to measure the electric field inside the large high power apparatus has not yet been well approved In this work, an optical measuring system, based on the Pockels effect, has been developed for measuring the field variation due to the corona discharges occurring in air and in oil. This system consists of He-Ne laser, single mode optical fiber, multi mode optical fiber, polarizing film, Y-cut LiNbO3 cell, photo detector, digital oscilloscope and personal computer with GPIB. For this purpose, optical probe has been specially designed and realized and put into the needle-plane electrode. Afterward, same measurement is carried out in oil. We demonstrate the characteristic of the optical measuring system and the measurement results.