• Journal of The Korean Society of Grassland and Forage Science
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• v.33 no.1
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• pp.15-20
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• 2013

This study was carried out to determine the optimum harvest stage of Italian ryegrass (Lolium multiflorum Lam., IRG) for maximum forage production during the spring season in Suwon, 2010. The variety of IRG was the early maturity type, 'Kowinearly', and six harvest stages (treatments) were first heading (T1), heading (T2), late heading to early bloom (T3), bloom to late bloom (T4), ripeness (T5), and late ripeness stage (T6). The dates of the first heading and heading of 'Kowinearly' were seen on 4 to 5 May, and 14 May, respectively. Plant length and dry matter (DM) percentage at first harvest were from 69 cm and 14.8% at T1 stage to 103 cm and 35.0% at T6 stage, respectively. The content of crude protein (CP) and in vitro DM digestibility (IVDMD) of T1, T2, T3, T4, T5 and T6 at first harvest were 15.6%, 10.6%, 10.1%, 8.1%, 7.3% and 5.4%, and 81.8%, 72.1%, 64.8%, 63.8%, 61.4% and 59.0%, respectively. The content of neural detergent fiber (NDF) and acid detergent fiber (ADF) were increased continuously with delayed harvest. A significantly higher yield of DM, CP and in vitro digestible DM (IVDDM) were observed for T3, and T4 (p<0.05). DM yield of 3,526 kg, 6,278 kg, 7,842 kg, 8,984 kg, 8,346 kg and 8,008 kg/ha, CP yield of 549 kg, 665 kg, 795 kg, 725 kg, 608 kg and 430 kg/ha, and IVDDM of 2,883 kg. 4,526 kg, 5,083 kg, 5,728 kg, 5,124 kg and 4,722 kg/ha at first harvest were recorded in T1, T2, T3, T4, T5 and T6, respectively. Regrowth yield of DM, CP and IVDDM were shown to be higher at T1 and T2 (p<0.05). However, no significant differences were observed between the two stages. Daily DM and DDM production of regrowth IRG were higher at T2, followed by T1. The total yield (at first and at regrowth) of DM, CP and IVDDM were significant higher for T2, followed by T3, T4 and T1 in order. At T2 stage, the yield was 11,089 kg, 1,254 kg, and 7,669 kg/ha in DM, CP, and IVDDM. In conclusion, the late heading to bloom stage was determined to be the optimum harvest stage for a single harvest, while the heading stage was a suitable stage of first harvest of 'Kowinearly' where two harvests were sought in a single year.

• Polymer(Korea)
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• v.25 no.4
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• pp.602-607
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• 2001

Bis(2-methoxyethyl)itaconate (bis(ME)I) was prepared for a new gel electrolyte containing double comb-like itaconate unit by esterification reaction of 2-methoxyethanol with itaconic acid. The copolymers were composed of AN/bis(ME)I = 9/1 ~ 1/1. The optimum mechanical properties and conductivity were obtained from the composition of AN/bis(ME)I = 5/1 and 6/1(25 ~ 35 wt%), LiClO4$_4$(15 wt%) and plasticizer (EC/PC = 1/1) (40 ~ 50 wt%). They showed a tough film and maintained a mechanical stability as a free standing film. The plasticized polymer gel electrolytes obtained from them showed ion conductivity of 8.12 ${\times}$ 10$_{-4}$ ~ 1.87 ${\times}$ 10$_{-3}$ S/cm. The maximum conductivity value obtained from our study was one order of magnitude higher than that of other PEO-based polymer electrolyte at ambient temperature.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.379-385
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• 1983

Forage productivity of Job's tears (Coix lachryma-jobi L.) and adlay (C. lachryma-jobi var. mayuen (ROMAN.) STAPF) and a hybrid corn (Kwangog) and sorghum-sudangrass hybrid (Pioneer 988) was compared in the southern part of Korea where black streaked dwarf virus' (BSDV) is prevalent. Emergence of Job's tears and adlay was more delayed compared to a corn or sorghum-sudangrass hybrid under the drought field conditions. Early growth and regrowth of Job's tears and adlay were less than those of sorghum-sudangrass hybrid. Fresh weight, dry weight, and digestible dry matter of Job's tears and adlay cut once approximately 40 days after flowering were much higher than those of two cuts at every flowering stage. Dry weight of one-cut Job's tears and ad lay harvested 40 days after flowering was similar to the total dry weight of three-cut sorghum-sudangrass hybrid but higher than that of silage corn. Digestible dry matter production was greater in the order of sorghum-sudangrass, corn, one-cut and two-cut Job's tears and adlay. Corn was severely infected with BSDV, but digestible dry matter was relatively high due to its higher in vitro dry matter digestibility. Among the Job's tears and adlay varieties, a variety of Job's tears with globular fruit shape was best for forage production due to its taller plant height, thick stem, wider leaf blades, higher leaf blade/total dry weight ratio, and higher forage yield. However, hulled grain yield of ad lay varieties was higher than that of Job's tears due to a higher hulled/rough grain ratio although they had similar rough grain yields.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.285-290
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• 2023

Poly-lactic acid (PLA) is the most promising polymer in additive manufacturing as an alternative to acrylonitrile butadiene styrene (ABS). Since it is produced from renewable resources such as corn starch and sugar beets, it is also biocompatible and biodegradable. However, PLA has a couple of issues that limit its use. First, it has a comparatively low glass transition temperature of around 60 ℃, such that it exhibits low thermal resistance. Second, PLA has low impact strength because it is brittle. Due to these problems, scientists have found methods to improve the crystallinity and ductility of PLA. Polyethylene glycol (PEG) is one of the most studied plasticizers for PLA to give it chain mobility. However, the blend of PLA and PEG becomes unstable, and phase separation occurs even at room temperature as PEG is self-crystallized. Thus, it is necessary to investigate the optimal mixing ratio of PLA-PEG at the molecular scale. In this study, molecular dynamics will be conducted with various ratios of L-type PLA (PLLA) or DL-type PLA-PEG (PDLA-PEG) systems by using BIOVIA Materials Studio.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1008-1013
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• 1999

Mechanical properties and morphology of pectin/starch blend films depending upon the composition and plasticizer ratio were studied. Blends were prepared continuously in a twin-screw extruder. Films were prepared using a single-screw extruder with slit die. Most of the blends showed a good thermoplastic behavior, while the blends with very high ratio of pectin/starch had a poor thermoplasticity. Tensile properties of blend films were changed significantly by the amount of glycerol and relatively little by the ratio of pectin/starch. Differential scanning calorimetry(DSC) curves of wet blends showed a transition similar to glass transition temperature(Tg) at about $125^{\circ}C$. It was found by Scanning electron microscopy(SEM) study that there exists a good interfacial adhesion between pectin and starch.

• Resources Recycling
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• v.10 no.2
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• pp.34-40
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• 2001

Post-consumer dairy HIPS bottles were gathered and recycled by the following processes; crushing into flakes, chemical treatment for the purpose of elimination aluminium caps, washing, and separation from other plastics, such as PP, PE, plasticized PVC These HIPS flakes were extruded into the chips using a single screw extruder. Recyclate HIPS chips were mixed with fly ash as an additive in the range of 5-50 wt%, which were formed from coal power plant. Recyclate HIPS chips mixed with fly ash were molded to investigate thermal and mechanical properties. Their samples, thermal and mechanical properties were measured via DSC, TGA, UTM, and impact strength analysis. The probable mechanical properties exhibited the range of 5∼30% fly ash contents for their applications.

• Polymer(Korea)
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• v.25 no.2
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• pp.160-167
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• 2001

The various compositions of polyimide (PI)/polyamideimide (PAI) composites were prepared by heat treatment of the solvent cast PI precursors/PAI blends. The optical micrographs showed that a good compatibility was observed between poly(amic acid) (PAA) and PAI, but in the case of PAME/PAI mixtures, a phase separation apparently occurred due to the absence of ionic and/or H-bonding forces. Regardless of PI precursors, the similar tensile properties were observed. The tensile modulus of the composites were higher than that of the neat polyimide. The X-ray diffraction patterns of the composites showed that the chain rearrangement of PI was increased due to the plasticizing effect of PAI, which has lower glass transition temperature than that of PI, during thermal imidization process.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.04a
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• pp.90-93
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• 2003

사초용 유채의 추파 재배에서는 경태, 주경엽수, 분지수, 분지엽수등의 수량 구성 형질과 생초수량은 휴폭 50cm $\times$ 주간 30cm의 점파구에서 가장 우수하였고 건물수량과 조 단백질함량, IVDMD, 가 소화 건물수량은 가장 밀식된 산파구에서 높았으며 NDF, ADF, Cellulose, Lignin등의 조섬유 함량은 식물체가 밀식된 상태에서 극히 세장한 관계로 가장 낮았다는 보고가 있었으나 (Ahn 등, 1989 ; Macforlane Smith 등, 1985) 우리나라 에서는 사초용 유채의 춘파 파종법(재식밀도)에 관한 시험연구는 아직 수행된바 없다. 따라서 본 시험에서는 사초용 유채의 재식밀도가 수량구성요소, 수량 그리고 영양가치에 미치는 영향을 구명하고자 Volox 품종을 공시하여 춘파 파종량 시험을 시험한 결과는 다음과 같다. 1. 초장을 제외한 경태, 주경엽수, 분지수, 분지엽수 등의 수량구성형질과 생초수량은 휴폭 50cm에 주간 30cm의 점파구에서 가장 우수하였다. 2. 건물수량과 조단백질 함량은 가장 밀식된 산파구에서 높았다. 3. IVDMD와 가소화 건물 수량은 산파구에서 가장 높았다. 4. NDF, ADF, Cellulose, Lignin 등의 조섬유 함량은 식물체가 밀식된 상태에서 극히 세장한 관계로 산파구에서 가장 낮았다.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.118-119
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• 1997

1. 서론 : 현대는 인구증가로 인한 생활하수 산업발달에 따른 폐수의 증가 및 오염물질의 다양화로 인하여 상수원이 점점 오염되어 가소 있는 반면, 국민소득 증가와 생활수준의 향상에 따라 맑고 깨끗한 물을 선호하는 계층의 욕구가 증대하고 몇 차례의 수질오염 사고로 인하여 수돗물에 대한 불신이 고조되고 있다. 이런 시점에서 환경부가 먹는 물의 수질을 검사한 결과, 몇몇 항목에서 기준을 초과하였다. 본 실험에서는 전국 먹는 물 수질을 분석하여 환경기준을 초과하는 주 항목을 선택한 뒤, 시판되는 몇몇 Module을 이용하여 과연 환경기준에 적합한 수질을 만들어 낼 수 있는가를 검토함으로써 각 지역별로 막 선택을 차별화하였다.

• The Journal of Korean society of community based occupational therapy
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• v.9 no.2
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• pp.23-31
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• 2019

Objective : The purpose of this study is to repeatedly conduct task-oriented training in scopolamine-induced dementia rats and as a result observe changes in the content of acetylcholine, a marker of cognitive function and central nervous system plasticity, to identify the improvement effect of dementia. Methods : It consisted of two groups. One group I was that did not perform task-oriented training in scopolamine-induced dementia rats and the other group II was that performed task-oriented training. Task-oriented training involved stretching, grasping and moving arms and walking obstacles on the legs. We performed a quantified passive avoidance test in the measurement of memory for cognitive function and compared the change in the content of acetylcholine for the plasticity of the central nervous system. Results : The results of the study are as follows: First, there was a significant improvement in cognitive function since the 4th days after task-oriented training of scopolamine-induced dementia rats(.00). Second, task-oriented training applied to scopolamine-induced dementia rats showed a significant increase in acetylcholine content. Conclusion : In this study, task-oriented training, which is often performed on senile dementia patients during occupational therapy intervention, was scientifically demonstrated in scopolamine-induced dementia rats by enhancement of cognitive function through memory improvement and increase in the content of acetylcholine confirming central nervous system plasticity.