• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.1
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• pp.42-47
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• 1990

Silage productivity of 7 corn and 3 sorghum hybrids was determined at two planting dates differing in rice black-streaked dwarf virus (RBSDV) infection rates in the southern part of Korea where RBSDV is prevalent. 1. Percent stand was similar between two planting dates, but that of corn hybrids (85.0-99.5 %) was higher compared with sorghum (59.8-82.3 %). Culm length of corn hybrids at April 23 planting was longer compared with May 20 planting, but that of sorghum hybrids was similar between two planting dates. 2. RBSDV infection rate of corn hybrids at April 23 planting was lower compared with May 20 planting, but sorghum was not infected at both planting dates. Among corn hybrids Suweon 19 was most severely infected, but Suweon 99 was least infected at both planting dates. 3. Percent ear bearing plants and earltotal dry matter (TDM) ratio of corn hybrids at April 23 planting was higher than those of May 20 planting. Among the corn hygrids percent ear beraring plants, ear/TDM ratio of Suweon 19 was lowest at both planting dates due to severe RBSDV infection. Ear/TDM ratio of sorghum hybrids was below 17.8 % due to sterility and partially bud damages. 4. Silage yield at April 23 planting was higher than that at May 20 planting and sorghum hybrids outyielded corn hybrids. Silage yield of Suweon 19 and Jinjuok was lowest due to severe RBSDV infection. 5. Crude protein was similar regardless planting dates, species, and varieties except the lowest P 931. Ether extract at April 23 planting was lower then that at May 20 and corn was lower compared with sorghum hybrids. Crude fiber and nitrogen free extracts(NFE) was similar between planting dates. Crude fiber of corn was lower, but NEF was higher compared with sorghum, but similar among hybrids in a species. 6. In vitro dry matter digestibility (IVDMD) at May 20 planting was higher than that of April 23 planting and corn was higher than sorghum hybrids. Digestible dry matter (DDM) of both corn and sorghum at April 23 planting was higher than that of May 20 planting. At April 23 planting DDM of all corn and sorghum hybrids was similar, but DDM of Suweon 19 and Jinjuok was lower than other corn and sorghum hybrids.

• Polymer(Korea)
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• v.28 no.1
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• pp.24-34
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• 2004

Transient sorption experiments were conducted among several combinations of fluoropolymers and various organic solvents. Fully fluorinated polymer tended to exhibit ideal sorption behavior, while partially fluorinated polymers showed anomalous sorption behaviors with a drastic acceleration at the final stage of uptake. Minimization of least-squares of the measured and predicted fractional uptake, which indicated the increasing degree of deviation from Fickian diffusion, gave values of 3.0${\times}$10$\^$-4/, 1.75${\times}$10$\^$-3/, 8.68${\times}$10/sup-3/, 1.75${\times}$10$\^$-2/, respectively, for perfluoroalkoxy copolymer, poly(ethylene-co-tetrafluoroethylene), poly(vinylidene fluoride), poly(ethylene-co-chlorotrifluoroethylene). From stress-strain tests, it was confirmed that non-Fickian diffusion is closely related to the significant variation of mechanical properties (such as modulus and tensile strength) of swollen polymer. Anomalous sorption behavior stemmed from non-Fickian diffusion caused by nonlinear disruption of polar inter-segmental bonds due to solvent-induced plasticization. Thus, it is imperative to investigate the diffusion behavior of swelling solvents in partially fluorinated polymers, especially for the application to barrier materials or perm-selective membranes.

• Journal of Animal Science and Technology
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• v.45 no.4
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• pp.607-616
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• 2003

This study was conducted to determine the effect of feeding a total mixed ration(TMR) of broiler litter(BL) and bakery by-product(BB) with additional BL or rice straw incorporated at 10% of dietary DM as a roughage source on behavior pattern, nutrient intake, digestibility, digestible nutrient intake, ruminal and blood parameters, and N balance of sheep. All the treatment diets were formulated to be isoenergetic[total digestible nutrients(TDN) 66.9%]. Compared with the conventional formulated feed - rice straw feeding system(control), feeding TMR with BL(T1) or rice straw(T2) at 10% of dietary DM resulted in reduced eating, ruminating and total chewing time(P<0.05), similar DM intake, low(P<0.05) digestible DM, OM, fiber and total nutrients intake, low(P<0.05) nutrients digestibilities except EE, similar ruminal characteristics(pH, VFA concentrations and ratios, efficiency of carbohydrate fermentation, NH3-N), and favorable N digestion and retention. There were no differences in the above parameters between T1 and T2 with the exception of increased(P<0.05) eating, ruminating and total chewing time for T2. These results suggested that a TMR of BL and BB with or without rice straw may replace the conventional formulated feed and rice straw in ruminant diets successfully and furthermore feeding the TMR with rice straw made sheep behavior pattern more favorable.

• Polymer(Korea)
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• v.28 no.2
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• pp.135-142
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• 2004

Poly(vinyl acetate) (PVAc) prepared by emulsion polymerization has broad applications for additives such as paint binder, adhesive for wood and paper due to its low glass transition temperature which help to plasticize substrate resins. Since emulsion polymerization has a disadvantage that surfactant and ionic initiator degrade properties of the product polymer, poly(vinyl acetate-co-butyl acrylate) (VVc-BA) was synthesized using potassium persulfate as catalyst and poly(vinyl alcohol) (PVA) as protective colloid to prevent the degradation. The copolymer latex product was internally plasticized and has enhanced colloid stability, adhesion, tensile strength and elongation. During VAc-BA emulsion polymerization, no coagulation and complete conversion occur with the reactant mixture of 0.7wt% potassium persulfate, 15wt% poly(vinyl alcohol) (PVA-217), and the balanced monomer that the weight ratio of vinyl acetate to butyl acrylate is 19. As the concentrations of PVA increase, the copolymerization becomes faster and polymer particles are more stable, resulting in enhanced mechanical stability of the VAc-BA copolymer. However, the size of the polymer particles decreases with increasing PVA contents. Properties of the VAc-BA copolymer, such as minimum film formation temperature, glass transition temperature, surface morphology, molecular weight and molecular weight distribution, tensile strength and elongation, were characterized using differential scanning calorimeter, transmission electron microscope and other instruments.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.1
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• pp.38-42
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• 1993

The objectives of this experiment were to suggest that the suitable mixture type for the herbage use under an intensive system of short-term pasture utilization in fallow land. The field trials were conducted over a 3-year (1989∼1991) period to evaluate the effects of mixture types (pure stands; orchardgrass (OG), simple mixtures; orchardgrass (OG) + red clover (RC), and complex mixtures (C. Mix; orchardgrass + tall fescue + Kentucky bluegrass + ladino clover) on the herbage yield and quality. Mean total dry matter yields per hectare over the three years were higher for OG + RC as 11,849 kg than for OG as 10,709 kg and for C. Mix as 11,371 kg (P<0.05). The concentrations of crude protein were not different among treatments while the concentrations of organic matter digestibility in total herbage over the three years from OG + RC were higher than OG (P<0.05). The total herbage crude protein yields were higher for OG + RC as 2,231 kg than for OG as 1,816 kg and for C. Mix as 2,053 kg (P<0.01). The total herbage digestible organic matter yields were higher for OG + RC as 7,147 kg than for OG as 6,116 kg and for C. Mix as 6,817 kg (P<0.05). On the other hand, organic matter intake per kg were different among the treatments, while organic matter intake per live weight kg from OG + RC as 338 g and C. Mix as 392 g were higher than from OG as 377 g (P<0.01). From the results, it could be considered that OG + RC simple mixture was suitable for the intensive short-term pasture utilization in the fallow land.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.1
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• pp.13-19
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• 2011

Purpose: The purpose of this study was to assess characterize overseas company's Cellulose acetate glasses frame sheets (overseas company's CA sheet) Also, the optimum content of plasticizer and melt extrusion condition of industrial CA resin were established for appropriate glasses frame. Methods: Overseas company's Cellulose acetate glasses frame sheets (overseas company's CA sheet) were characterized by $^1H$-NMR, GPC, and TGA. Also, the optimum content of plasticizer and melt extrusion condition of industrial CA resin were established. Results: The plasticizer of overseas company's CA sheet measured by $^1H$-NMR was diethyl phthalate, and its content was measured 30 wt% by TGA. Also, industrial CA resin showed enough melting behavior in the range of 190~200$^{\circ}C$. Compared to overseas company's CA sheet's tensile strength value of 2.2~2.8 kgf/$mm^2$, industrial CA resin exhibited sufficient tensile strength value of 2.3 kgf/$mm^2$ for glasses frame. Conclusions: Industrial CA resin with 30 wt% plasticizer content would be a promising material for glasses frame prepared by melt extrusion to replace China CA sheet.

• Journal of the Korean Electrochemical Society
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• v.10 no.3
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• pp.213-218
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• 2007

In order to find out proper PVdF gel polymer electrolyte for Li/S battery, we investigated PVdF gel polymer electrolytes with various glyme type plasticizer such as polyglyme, tetraglyme, triglyme. The organic solvents as triglyme, tetraglyme, polyglyme (Mn = 250, 500) has different chain length of ethylene oxide(EO) in solvent of glyme system. ionic conductivity decreased as increasing chain length of EO in plasticizers. Ionic conductivity of PVdF gel electrolyte with tetraglyme, triglyme, polyglyme (Mn = 250, 500) at room temperature was $5{\times}10^{-4},\;3{\times}10^{-4},\;6{\times}10^{-5},\;3{\times}10^{-5}\;S/cm$, respectively. Li/S cell with PVdF gel polymer electrolyte using tetraglyme plasticizer had low interfacial resistance and the highest initial discharge capacity of 1232 mAh/g of active sulfur, which was about 70% utilization of theoretical value.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.225-228
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• 2018

Plasticizers added to thermoplastic polymers are known to shorten the life of products due to the elution to outside, and some of them are harmful to our environment and human body. Since the use of phthalate plasticizers suspected of being carcinogens has been gradually prohibited, there is a need for environmentally friendly plasticizers that can replace them. Most of the substances have a low compatibility with resin, high cost and lack of safety verification. Therefore, in this study, four kinds of norbornene dialkyl ester compounds possessing excellent physical properties, which are also reported as safe compounds from the toxicity evaluation, were added to PVC resin to evaluate the possibility of human exposure by leaching, and also the potential usage as plasticizer candidates alternative to commercial ones including DEHP, DINCH and DOTP. The test was carried out according to the American standard test method (ASTM). The results showed that di-2-ethylhexyl-5-norbornene-2,3-dicarboxylate (DEHN) in aqueous solvents and diisopentyl-5-norbornene-2,3-dicarboxylate (DIPN) compounds in oil solvents were superior or equivalent to DEHP. In addition, all four norbornene compounds showed lower values than 100 ppm, which is considered to have an influence on the environment, indicating that the polar norbornene structure affects the elution.

• Journal of the Korea Concrete Institute
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• v.24 no.6
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• pp.745-752
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• 2012

This paper studies the effect of the compressive strength for combined alkali-activated slag mortars. The effect of activators such as alkali type and dosage factor on the strength was investigated. The alkalis combinations made using five caustic alkalis (sodium hydroxide (NaOH, A series), calcium hydroxide ($Ca(OH)_2$, B series), magnesium hydroxide ($Mg(OH)_2$, C series), aluminum hydroxide ($Al(OH)_3$, D series), and potassium hydroxide (KOH, E series)) with sodium carbonate ($Na_2CO_3$) were evaluated. The mixtures were combined in different dosage at 1M, 2M, and 3M. The study results showed that the compressive strength of combined alkali-activated slag mortars tended to increase with increasing sodium carbonate. The strength of combined alkali-activated slag mortars was better than that of control cases (without sodium carbonate). The result from scanning electron microscopy (SEM) analysis confirmed that there were reaction products of calcium silicate hydrate (C-S-H) and alumina-silicate gels from combined alkali-activated slag specimens.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.2
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• pp.147-151
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• 1987

This study was conducted to evaluate the effect of the liquid waste from methane fermentation on chemical components, digestible dry matter and net energy of pasture mixtures of orchard grass, tall fescue, Kentucky bluegrass and ladino clover. The total crude proteins and crude ashes increased with the application of liquid waste, but N-free extracts decreased somewhat and it didn't affect the content of crude fat and crude fiber. Amounts of neutral detergent fiber and acid detergent fiber increased with increasing application of liquid waste and the content of cellulose in cell-wall constituents decreased, but hemicellulose increased. The digestible dry matter was produced 405 kg/10a at optimum application of 42 MT/10a liquid waste compared to NPK check plot of 233 kg/10a. The starch value and net energy lactation were 291.3 KStE and 3450 MJ-NEL respectively indicating that the optimum application of liquid waste increased their values.