• Journal of the Korean Society of Safety
• /
• v.15 no.1
• /
• pp.66-71
• /
• 2000

This paper presents a development of an electric hole cutter for agricultural polyethylen film. Mechanical hole cutter with blades and electrical hole cutters are being tried in products now. But Mechanical hole cutter systems have a few faults. So the hole cutter systems using electrical heater have mainly been developed and optimized. Computer aided engineering was introduced for the purpose of electric heated hole cutter being developed, because it helped reduce the unnecessary tests. Three types of heated cups were surveyed with MSC/Nastran, and the type of model C was most effective in heat transfer.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.35 no.12
• /
• pp.555-559
• /
• 1986

It is shown that water tree grown using the water needle method in polyethylen do not behave as conductor but as dielectrics. It is decuded that water trees are not non-interconnected cavities. This result is confirmed by gas flow measurements through freeze-fractured water trees.

• Korean Journal of Medicinal Crop Science
• /
• v.3 no.2
• /
• pp.156-164
• /
• 1995

The study was carried out to elucidate the influenced of shading and mulching with polyethylen vinyl on growth and yield of Cinidium officinale Makino, and improve the cultivation method of those medicinal plants in northern area of Gyeong-buk province, Korea. Top fresh weight of Cinidium officinale Makino was increased by both 35 % and 55% shading compared to the non-shadingand decreased by 75 % shading, but that of Ligusticum chuanxing Hart. Was decreased by the shading tested The summer wilt of Cinidium officinale Makino severely occurred in non-shading but greatly reduced by 55 % or 75 %shading, while no difference was observed in Ligusticum chuanxing Hort, between the shading and the non-shading. Dry root yield Cinidium officinale Makino was increased by 17 % and 19 % in 35 % and 55 % shading levels, respectively, compared to the dry root yield(254kg/10a) in non-shading. However, it was decreased in Ligusticum chuaxing Hort. by the shading. Emergence ratio of Cinidium officinale Makino was increased by black polyethylen vinyl mulch but decreased by transparent polyethylen vinyl mulch, compard to non-mulch. Polyethylen vinyl mulch increa­sed the top fresh weight of Cinidium officinale Makino Especialy black polythylen vinyl mulch was very effective on increasing the top fresh weight. Dry root yield of Cinidium officinale Makino was increased by 32 % and 30 %, respectively, compared to the non-shading.

• 보존과학연구
• /
• s.11
• /
• pp.221-233
• /
• 1990

4종의 상태가 좋은 그리고 2종의 열화된 수침 침엽수재(Pinus massoniana,Pinus.densiflora, Cunninghamia lanceolata, Crypto meria japonica)를 PEG400과PEG4,000용액으로 처리하였다. 모든 종이 안정화처리에 똑같게 반응을 보였다. 전체적으로 건전재나 약간 열화된 수침재는 PEG400 20%용액으로 처리한 결과 치수안정화가 달성되었다. PEG4,000의 50%용액으로 처리한 목재의 건조에 대한 수축은 심하게 열화된 목재에 대해 열화되지 않은 목재에서는 1/2에서 1/3정도 감소하였다. 엄격한 상관관계가 최적안정화를 위해 PEG와 목재의 밀도간에 존재한다. 최적으로 처리된 목재는 86%상대습도 이하에서는 축축하게 되지 않는다. PEG400과 PEG4,000으로 처리한 2단부함침이 황해에서 구조된 중국 정크선의 목재를 안정화시키는데 대해 추천된다.

• Journal of the Korean Wood Science and Technology
• /
• v.43 no.6
• /
• pp.784-791
• /
• 2015

Polyethylene glycol (PEG) impregnation prevents a red pine disk from cross-sectional checking during drying. Percentage of PEG Retention (PPR) was measured by the experimental methods of aceton extraction and moisture conditioning in a saturated salt solution and the effect of acetylation on PEG impregnated wood was investigated. PPRs of the kiln-dried specimens were much higher than those of the air-dried by at least four times and within the kiln-dried specimens those of the sapwood were higher that those of the heartwood by two times. These results were confirmed by the moisture conditioning experiment. Acetylation increased the weights of the kiln-dried specimens much less than those of the air-dried. It was revealed that acetic anhydride solution eluted PEG-1000 in the specimens. It is concluded that kiln-drying is more effective than air-drying for the increase of PPR and that acetylation eliminates the difference between the kiln- and air-dried specimens.

• Journal of the Korean Society of Safety
• /
• v.6 no.2
• /
• pp.15-20
• /
• 1991

In this paper, we have investigated the effect of organic additives and prestressed D C. voltage on the impulse tree initiation in low density polyethylene. The five klnds of organic compounds was selected for the purpose of inhibiting tree initiation and 10 wt % of each additive was mixed in low density polyethylene. The positive or negative impulse voltage was applied after prestressed D.C. voltage was applied in order to investigate the effect of the space charge influenced on tree initiation. The lengths of tree initiation in case of belng same polarity between prestressed D.C. voltage and impulse voltage were longer than those in case of being different polarity between prestressed D.C. voltage and impulse voltage. When the polarity prestressed D.C. voltage was the different plarity of impulse voltage, the length of tree initiation increased with increasing the prestressed D.C. voltage and decreasing the rest time Among the organic additives used in this paper, the m-cresol can be shown to be the most effective inhibiter to tree initiation.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.11a
• /
• pp.32-32
• /
• 2003

최근 환경오염에 대한 문제가 심각해지면서 인체에 유해한 유기물질의 분해에 대한 관심이 높아지고 있으며 따라서 뛰어난 광촉매 특성을 보이는 타이태니아(TiO$_2$)에 대한 많은 연구가 수행되고있다. 타이태니아가 보이는 결정상 중에는 brookite, anatse, rutile이 있는데 이 중에서 anatse 상이 가장 우수한 광촉매 특성을 나타내는 것으로 알려져 있다. 그러나 anatse 상을 얻기 위해서는 $600^{\circ}C$ 이상의 온도로 열처리를 해야 한다는 문제점이 있으며 광촉매 특성을 향상시키기 위해서는 anantase 나노결정을 제조하여 표면적을 극대화시 키는 것이 요구되고 있다. 본 연구에서는 이러 한 두 가지 문제점을 해결하기 위하여 Polyethylen oxide(PEO)-TiO$_2$ 나노하이브리드를 Sol-Gel공정을 이용하여 합성하였으며 이들에 대한 hot-water treatment를 통하여 10$0^{\circ}C$ 이하의 저온에서 anatase 나노결정상의 분말을 합성하는데 성공하였다. 이는 SiO$_2$-TiO$_2$계 하이브리드에서만 hot-water treatment를 통하여 anatase로 결정화가 가능하다는 기존의 연구결과와 상반되는 결과로서 무기질 성분으로서 TiO$_2$만 존재하는 하이브리드에 대한 hoi-water treatment를 통하여 anatase결정상이 형성될 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1997.04a
• /
• pp.111-115
• /
• 1997

There exists a interface among the different kinds of materials in the solid insulating ones, which effects on the insulating capability heavily. The insulating construction has been developed for each usages and take themselves into several sorts. The conjunction between CV cables have the electrical weakness of solidity and solid interface, so they were focused at the long distance-line. To this background, it is very important to get the information on the interface influencing on the insulating capability of cable and to observe its procedure. In this paper, the interface was made artificially to research the effect owing to the toughness of interface, which results in the aging and treeing proceeding was observed. The polyethylen, as is generally using for the cable, was taken in this research.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.16 no.1
• /
• pp.17-22
• /
• 1980

Two plied twine, of which yarn is cored by abacca fibers and wrapped by polyethylen fibers, has been used for the material to web the wing net in the anchovy boat seine. This conventional twine revealed the disadvantage of which tensile strength goes from bad to worse. To improve the disadvantage, authors developed the new twine which is plied with three yarns, each yarn is cored by polyvinyliden chloride fibers and wrapped by polyethylen fibers. To compare the physical properties of the two kinds of twine, some factors are valued and the following results are found. 1. The conventional twine shrinks 4 to 7 percent when it was soaked in fresh water for 24 hours, whereas the improved one shrinks little. 2. The specific gravity of the conventional twine is valued 1. 04 to 1. 025 after soaking the twine in fresh water for 24 hours, in spite of including abacca to make the gravity heavier than that of sea water, whereas the improved ones are valued 1. 06 to 1. 09 without soaking. 3. The stiffness of the two kinds of twine differs little. 4. The breaking strength and the elastic recovery of the improved twine are greater than the conventional one. 5. Mesh size of the actual fishing net, webbed by the improved twine and employed in commercial fishing for 6 months, varied little.

• The Korean Journal of Mycology
• /
• v.16 no.4
• /
• pp.247-252
• /
• 1988

The uptake of isolated Lyophyllum ulmarium chromosomes by Ganoderma applanatum protoplasts was induced with polyethylen $glycol+CaCl_2+glycine$. Uptake products of chromosomes by protoplasts showed micro-and macrotransgenome type. The former was slowly growing and unstable, the latter was outgrowing and stable mycelial colonies which made thick hyphae of width and segregation of mycelial colony on GCM containing benomyl. A comparison of macrotransgenome type was using isozyme analysis of esterase. The enzyme pattern of two transformants was distinct in position and quantity compared with parents.