본 논문은 용액법으로 성장시킨 저밀도 폴리에틸렌 박막의 냉각 조건에 따른 결정화도의 관계와 냉각 조건에 따른 전기전도현상, 유전특성 및 절연파괴에 관하 연구로서 박막은 140[˚C]에서 2시간 유지후 냉각 조건을 달리하여 제작하였다. 결정화도는 XRD를 이용하여 측정하였으며 냉각 속도가 빠를수록 결정화도가 감소함을 볼 수 있었다. 전기전도현상은 냉각 조건에 무관하게 저전계에서는 이온전도특성이 나타나고 고전계에서는 공간전하제한전류이론이 지배적이다. 절연파괴전계는 냉각속도가 증가할수록 증가하고 self-healing절연파괴 방법에서는 시험회수가 증가할수록 증가하였다.
The procedure to prepare an acrylic emulsion water repellents by blending of arcylic copolymer, activated polyethylene, wax, and emulsifiers was published in the previous paper. After the treatment of the prepared water repellents on a cotton fabrics with and without textile finishing resin, washability, contact angle, tearing strength, and crease recovery were tested. As the result, there were remarkable improvements in physical properties. Proper curing temperature of the synthesized water repellents impellents was 150℃ : proper using concentration was 5wt% : sodium acetate was the best catalyst for water repellents among the used, and proper concentration was 1.0wt%.
Durable softening water repellents such as PODCWs were prepared by blending cationized compound of poly(octadecyl methacrylate-co-2-diethylaminoethyl methacrylate), of which synthetic methods were reported in the previous paper, activated polythylene, waxes, and emulsifiers. Water repellency of prepared PODCWs was measured by performing water repellent finish to various fabrics, PODCWs showed a good water repellency for P/C blended fabrics and their repelling tendency was in the order of P/C blended fabrics〉cotton fabrics〉nylon taffeta. The initial water repellencies of PODCW-1 and PODCW-2 were 100 and 100- points, respectively, for P/C blended fabrics. And also, PODCW-1 and PODCW-2 were confirmed as durable water repellents with the results of making little difference of water repellency as ±5 point after and before washing.
It is well known that the membrane permeation in pervaporation is governed by both the chemical nature of the membrane material and the physical structure of the membrane and also the separation can be achieved by differences in either solubility, size or shape. The solubility of the penerrant in the polymeric membrane can be described qualitively by applying the Hildebrand relation [1] which relates the energy of mixing of the penerrant and the polymer material. Froehling et al. have tried to predict the swelling behavior of polymers for the systems of polyvinylchloride(PVC)-toluene-methanol, PVC-trichloroethylene-nitromethane and PVC-n-butylacetate-nitromethane[2]. The former two systems which do not show the donor/acceptor interactions upon mixing showed the successful results[2]. In addition to this technique, there are several other possible approaches to predict the swelling behaviors of polymers, such as the surface thermodynamic approach[3, 4], the comparison of the membrane polarity with the solvent polarity in terms of Dimroth's solvent polarity value[5].
Background: The present study assessed the response of kenaf (Hibiscus cannabinus L., Jangdae) seed to NaCl and the effects of polyethylene glycol (PEG) on kenaf seed germination and vigor. Methods and Results: Seed germination ranged from 11.3% to 58.8% after 24 hours of immersion in NaCl concentrations from 0% to 0.5%. The priming treatments had lower electrical conductivity (EC) values for the seeds than for the control and a deteriorated palisade layer. Priming in 10% PEG for 48 hours increased the germination upto 96.3% in H2O solution and 98.8% in 0.3% NaCl solution compared to that of the control (78.8%). Germination synchronization, and shoot and root growth of the primed seeds were greater than those of the control. The T50 of the control in H2O and 0.3% NaCl solution was 22 and 28 times, respectively. After priming, nine times was sufficient to reach T50 in both solution. The mean number of days to germination (MDG) decreased from 1.43 days for the control to 0.55 days for 0% PEG in H2O solution and from 1.57 days for the control to 0.56 days for 0% PEG in 0.3% NaCl solution. The dry weight after the 10% PEG treatment was higher than that of the control. Conclusions: Taken together, 10% PEG treatment for 24 hours is recommended for kenaf seed invigoration before planting.
본 연구는 2015년과 2016년에 ‘상주둥시’ 감의 수확시기 를 달리하여 수확 후 PE필름, 1-MCP 및 AVG를 처리가 저온저장동안 과실의 품질에 미치는 영향을 조사하였다. 2016년 과실 수확시기는 2015년에 비하여 10일 빠른 조기 수확을 실시하였다. 과실의 에틸렌 발생 정도는 조기수확 한 과실들에서 현저히 낮았고, 과실의 경도는 저온저장동안 1-MCP 처리구들이 다른 처리구의 과실에 비하여 높게 유지되었다. 과실의 감모율은 수확기를 달리한 모든 과실 들에서 PE 필름 처리 과실들에서 현저히 억제되었다. 성숙기에 수확한 과실은 저온저장 중 과실의 꽃받침 부위과 경와부의 과피색(L* 및 b*) 변화를 보면 무처리와 PE필름 처리구에 비하여 1-MCP 처리구들이 그 변화정도가 낮았다. 과실의 부패와 연화정도는 PE필름 처리 과실들에서 높게 나타났지만 AVG 처리구들에서는 부패과 발생이 없었다. 그리고 조기수확한 과일은 성숙기에 수확한 과실에 비하여 경도가 높게 유지되었고, 과피색의 변화가 낮은 경향을 보였고, 성숙기에 수확한 과실들은 당도, 과피의 적색 (Hunter a 값) 발현 및 호흡율이 높게 나타났다. 따라서 감 과실의 저장성 향상을 위해서는 조기수확이 중요한 요인으로 작용하고 또한 수확 후 1-MCP 처리가 과일의 경도를 높게 유지하고 과피색의 변화를 억제하였으며, 과실의 감 모율은 PE 필름 처리에 의해 현저하게 억제됨을 확인하였다.
This study was carried out to identify the optimum seeding dates for selecting a double-cropping system and to assess the effect of polyethylene film mulching on the yield of Proso millet. Seeds of the varieties Hwanggeumgijang and Ibaegchal were sown in Miryang on five different dates: 1st (May 25), 2nd (June 15), 3rd (June 25), 4th (July 5), and 5th (July 15), with and without polyvinyl mulching. The varieties have different characteristics, for example, Hwanggeumgijang is an early-maturing type and more sensitive to temperature, whereas Ibaegchal is a medium-maturing type and more sensitive to the duration for which it is exposed to sunlight. Late-sown Hwanggeumgijang had a short heading date from seeding and required a low accumulated temperature. It also had a shorter period of heading, a shorter culm length and a shorter diameter of stem. In contrast, it had had a higher number of ears per m2 although similar ear length and similar 1000-grain weight. The yield potential of Hwanggeumgijang was found to decrease at a late seeding date. In particular, it significantly decreased at the seeding date of July 15. In the case of cultivation with polyvinyl mulching, the period of heading was shorter by 2–4 days and the yield potential was increased by approximately 12–32%. The length and diameter of culm in Ibaegchal were slowly decreased, but the length of ear, the 1000-grain weight and the yield potential were similar for all seeding dates (except July 15) and cultivation with and without mulching. When sown late, the length and diameter of the culm of Ibaegchal very rapidly decreased by the July 15 seeding date. The protein content of Ibaegchal was higher but the amlyose content of Ibaechal was lower compared to Hwanggeumgijang. At late seeding dates, the protein contents of the two varieties increased but the amylose contents were similar.
본 연구는 건강 기능성 농산물로 각광을 받고 있으면서 수요와 재배면적이 점차 확대되고 있는 기장의 생산량 증대와 자급률 향상을 위한 체계적인 재배기술을 확립하기 위한 기초자료를 얻고자 재식밀도와 PE 멀칭에 따른 생육 및 수량에 미치는 영향을 알아보았다.
1. PE 멀칭에 따른 간장은 1년차 PE 멀칭구에서 138 cm로 17 cm 길게 나타났으며, 간경은 8.33 mm로 2년차 PE 멀칭구에서 굵게 나타났고 지상부생체중은 무멀칭구보다 PE 멀칭구에서 연차간 모두 37.7%, 9.0% 많이 나타났다.
2. 연차간 재식밀도에 따른 생육특성에서 간장은 1, 2년차 모두 재식밀도가 높은 10 cm처리구에서 130, 142 cm로 가장 길게 나타났으며 재식밀도별 뚜렷한 차이를 보였다. 간경은 2년차에서는 간장과 반대로 재식밀도가 가장 낮은 20 cm처리구에서 가장 굵은 8.43 mm로 나타났다.
3. 이삭장은 PE 멀칭구에서 34.1, 40.7 cm로 무멀칭구 대비 20.1, 13.7% 더 긴 것으로 나타났다. 종실중 2년차에서는 PE 멀칭구에서 무멀칭구 대비 8.6% 더 무겁게 나타났으며, 천립중에선 무멀칭구에서 5.3% 더 무겁게 나타났다. 종실수량은 1·2년차 모두 뚜렷한 차이를 보였으며 1년차에서는 PE 멀칭구에서 305 kg·10a-1, 2년차에서는 242 kg·10a-1으로 나타났다.
4. 재식밀도에 따른 이삭장과 이삭당 종실중은 1·2년차 모두 재식밀도 낮을수록 길거나 무겁게 나타났으며 종실수량은 연차간 모두 15 cm처리구에서 265 kg·10a-1, 253 kg·10a-1으로 수량구성요소에서 높은 값을 보인 20㎝처리구 보다 10.0, 15.5% 높은 것으로 나타났다.
Polyethylene and polystyrene are frequently used resins for making food container including cup noodle bowls. In the pre-sent study, we investigated the potential risks of polyethylene and polystyrene cup noodle containers by cytotoxicity tests such as agar diffusion assay, filter diffusion assay, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. We exposed CCL-1 mouse fibroblast cell line to the polyethylene and polystyrene cup noodle containers indirectly through agar gel. We also used eluents derived from the cup noodle containers by storing them for 24 h at 70℃ in liquids, such as distilled water or dimethylsulfoxide (DMSO). Both polyethylene and polystyrene cup noodle container specimen were found to be non-cytotoxic in agar diffusion assay as well as filter diffusion assay. The eluents from polystyrene using DMSO showed slight cytotoxicity in MTT assay.
Wheel tracking test and ice pull-out test were performed in laboratory on dense grade asphalt mixture and asphaltmixture including 2.5% of 19mm PE aggregates. Meanwhile, temperature change, thermal conductivity, and snow meltingspeed were measured for both dense grade asphalt and PE aggregate mixed asphalt pavement via field testing on a testroad. Laboratory test results show that dynamic stability was improved and ice was removed easily by mixing PEaggregates in an asphalt mixture. Moreover, the existence of PE aggregates enhances heat insulation and snow meltingspeed due to the lower thermal conductivity compared to ordinary dense grade asphalt mixtures.
This study was conducted to find out the optimum composition of nursery soil for raising seedling of ginseng (Panax ginseng C. A. Meyer). Total 9 kinds of raw materials were used such as peat-moss, perlite, leaf mould, rice bran, gull's guano, castor-oil plant bark, palm bark, cow manure and chicken manure for optimum composition of nursery soil in ginseng. Occurrence of damping-off in ginseng was lowered about 50% in nursery soil type 1, 2 and 4 than in other types nursery soil in June, and occurrence rate of rusty root also lowest in nursery soil type 1. As the salinity of nursery soil increased, so did the occurrence of physiological disorder in ginseng seedling. The cause of salinity increasing in nursery soil has closely relation to NO3-N, P2O5 and Na+ content. Plant height, root length, diameter and weight were longer and heavier in nursery soil type 1 (mixing ratio of peat-moss, perlite and leaf mould was 50 : 20 : 30 based in volume) than in other types of nursery soil. So nursery soil type 1 was selected for raising seedling of ginseng. pH and electric conductivity (EC) of selected nursery soil type 1 was 5.55 and 0.13 dS/m. Contents of NO3-N and P2O5 were 21.0 and 40.0 mg/L, and K+ 0.36, Ca2+ 3.38, Mg2+ 2.01 and Na+ 0.09cmol+/L, respectively.
Polyethylene glycol (PEG) solution is currently used to prepare the colon before colonoscopy. Hyponatremic encephalopathy is a condition with neurologic symptoms such as headache, vomiting, confusion, seizure, and sometimes respiratory arrest. A 55-year-old woman presented to our emergency department with generalized tonic-clonic seizure and mental change after ingestion of PEG solution 2 L with water. Serum sodium concentrations was 115 mmol/L. After correction with hypertonic saline for 12hrs, serum sodium concentration reached 129 mmol/L and mental status recovered. We experienced a case of acute hyponatremic encephalopathy resulting from ingestion of PEG solution 2 L for colonoscopy.
In this study, thermoplastic starch (TPS), cross-linked starch (CS), and cross-linked starch modified with glycerol (CTPS) were prepared, and the mechanical properties of the compatibilized low-density polyethylene (LDPE) blends (LDPE/TPS, LDPE/CS, and LDPE/CTPS) were investigated and compared with those of uncompatibilized LDPE/TPS, LDPE/CS, and LDPE/CTPS blends. Maleic-anhydride-grafted polyethylene was used as the compatibilizer. The enhanced tensile strength and elongation at break for the compatibilized LDPE/modified starch blends are a result of the improved compatibility between LDPE and the modified starch, which was confirmed by torque measurements and scanning electron microscopy.
This research evaluated the environmental impact of polyethylene water supply pipe which is a target of voluntary agreement by Waste Charge System using Life Cycle Assessment (LCA). When analyzing the contribution of each impact category to the environmental score, resource depletion had the highest contribution at 57% and it was followed by global warming with 35% of contribution. Amongst the entire process and stage, production of raw materials, production of goods and disposal had about 60%, 18% and 18% of contribution, respectively. For resource depletion which was found to have the highest contribution, production of raw materials, production of goods and disposal accounted for nearly 77%, 11% and 7% of it, and the impact category of resource depletion which belongs to production of raw materials accounted for nearly 44% of the whole environmental score. Here, it was found that 88% of it resulted from crude oil. When analyzing the contribution of each stage to global warming that is the key issue of low carbon green growth, then, production of raw materials, production of goods and disposal showed around 38%, 29% and 28% of contribution, respectively. As the result, production of goods and disposal had higher contributions than resource depletion. Electricity used for production of goods is the major cause of global warming, and electricity used in the recycling process and incineration occupied about 65% and 36% of the disposal stage. In conclusion, we need to seek for plans to reduce the use of electricity through optimization of energy use during the production of goods and disposal, in order to establish an environmental and economical competitiveness of PE-related enterprises that are operated on a small scale.
변형경화형 시멘트 복합체(SHCC)는 직접인장 상황에서 FRCCs에 비해 우수한 변형경화 특성을 갖는 재료이다. 하지만 SHCC는 일반적인 콘크리트에 비해서 시멘트비율이 높은 부배합 이며, 이에 따라서 자기수축이 큰 특성을 갖는 재료이다. 따라서 시멘트 복합체 내에 팽창재를 대체함으로써 수축저감을 통한 성능향상을 기대하였다. 이 연구에서는 각 강도별 SHCC의 배합에 팽창재를 대체함에 따른 역학적특성을 평가하고자 하였다. 시험결과 설계기준 압축강도 70MPa 배합이 압축, 인장, 휨, 시험에서 우수한 역학적 특성을 나타내었으며, 균열 특성에서는 팽창재를 대체한 SHCC가 균열분산 및 연성에서 우수한 특성을 나타내었다.
김치를 기체 투과도가 조절된 플라스틱 용기, 시유옹기, 유리병을 사용하여 각각 발효하였을 때, 그 품질특성이 어떻게 변화하는지를 에서 8주간 발효하면서 관찰하였다. 다른 용기에 보관한 김치에 비해, 투과도 조절 플라스틱 용기에 보관한 김치의 pH 감소가 적었으며, 산도 역시 8주 후에 0.99로 나타나 증가율이 가장 적게 나타났다. 미생물수의 변화를 보면 투과도 조절 플라스틱 용기에 보관한 김치가 총균수의 증가는 적고, 유산균의 증가는 높게 나타