• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.3
• /
• pp.2131-2134
• /
• 2015

In this study, It has been demonstrated a new and realizable possibility of the ferroelectric random access memory devices by all solution processing method with paper substrates. Organic ferroelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) thin films were formed on paper substrate with Al electrode for the bottom gate structure using spin-coating technique. Then, they were subjected to annealing process for crystallization. The fabricated PVDF-TrFE thin films were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). It was found from polarization versus electric field (P-E) measurement that a PVDF-TrFE thin film on paper substrate showed very good ferroelectric property. This result agree well with that of a PVDF-TrFE thin film fabricated on the rigid Si substrate. It anticipated that these results will lead to the emergence of printable electron devices on paper. Furthermore, it could be fabricated by a solution processing method for ferroelectric random access memory device, which is reliable and very inexpensive, has a high density, and can be also fabricated easily.

• Korean Journal of Weed Science
• /
• v.6 no.1
• /
• pp.42-47
• /
• 1986

To select herbicide for sesame under vinyl mulching, growth and yield of sesame and effects of weed control were investigated in various herbicides treatment with standard alachlor. Even if alachlor showed high effects in weed control, it coused phytotoxicity under vinyl mulching. But napropamid 150g ai. per 10a was not only highly effective for weed control but also stable in herbicide injury. Therefore, napropamid-treated plots showed remarkably flourishing growth and high yield compared with alachlor 66g ai. per 10a.

• Korean Journal of Medicinal Crop Science
• /
• v.8 no.3
• /
• pp.209-215
• /
• 2000

This study was conducted to improve the productivety of Ligusticum chuanxiong HORT. and Cnidium officinale MAKINO by establishing the effects of cultivating conditions. Growth characteristics of underground part of L. chuanxiong under the different mulching treatment showed the highest growth and yield in black vinyl mulching treatment. The highest dry weight of underground parts per plant in mulching treatment was 47.9g at white shading treatment while the lowest one was 16.5g at black shading treatment. Growth characteristics of underground parts C. officinale under the different mulching treatment were the higher in black vinyl mulching rather than in rice straw mulching and white vinyl mulching. Dry weight of underground parts per plant of C. officinale under the different shading treatments was the highest(37.8g) under the white shading while it was lowest(12. 2g) under the black shading.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.32 no.1
• /
• pp.10-15
• /
• 1987

The experiment was designed to determine the proper shading rate and shading materials to decrease the excessive dried leaves during cure of burley tobacco. Five shading rates and seaven shading materials were applied on the pipe vinyl house from initial stage or yellow stage of cure. Temperature was lower and weight-loss of leaves delayed with shading from initial stage to browning stage of cure. Excessive dried leave were largely decreased as shading rate was increased to 70%. However, at shading rate more than 70%, its decreasing extent was fewer. Price per kg and physical properties improved considerably at shading rate of 50%. Shading materials alone could not completely prevent excessive dried leaves but it could decrease them. Orange, white and purple color vinyl among shading materials had so effects of shading as the black shading cloth during curing. However, white color vinyl didn't endure more than a few months due to sunshine. A difference of light quality in visible light was no significance on air curing.

• Polymer(Korea)
• /
• v.27 no.5
• /
• pp.429-435
• /
• 2003

Vinyl addition copolymerizations of norbornene (NB) and 5-vinyl-2-norbomene (VNB) were carried out using a cationic η$^3$-allyl palladium catalyst in the various mole ratio of comonomers. The copolymers could be obtained in good yield (65∼85%) with high weight-average molecular weights (M$_{w}$ > 760,000). Depending on increasing VNB contents, the molecular weight and yield of the copolymers decreased. FT-IR analysis confirmed that actual contents of VNB in polymer were proportional to the feeding content of VNB. From $^1$H-NMR spectroscopy, we found that both exo and endo VNB isomer were copolymerized with NB. Thermal stabilities of NB-VNB copolymers were independent on the VNB content and their initial decomposition temperatures were about 300 C. The NB-VNB copolymers were followed by epoxidation by using m-CPBA and hydroxylation by 9-BBN, respectively, and these post-polymers were characterized by FT-IR spectroscopy and $^1$H-NMR analysis..

• Applied Chemistry for Engineering
• /
• v.1 no.2
• /
• pp.182-189
• /
• 1990

Various crosslinked poly(4-vinylpyridines) having different degrees of crosslinking were prepared by radical copolymerizations of 4-vinylpyridine with N, N'-2, 6-pyridinebisacrylamide as a crosslinker. The abilities of these crosslinked polymers to bind methyl orange and butyl orange were investigated at various temperatures in a buffer solution of pH 7. The first binding constants were evaluated from the equilibrium binding amounts. The first binding constants against the temperatures showed bell-shaped curves. Also, the first binding constants against the degree of crosslinking showed bell-shaped curves. When the temperature and the degree of crosslinking of maximum binding in the curves of these binding systems were compared with those of previous systems containing crosslinked poly(4-vinylpyridines) prepared by using N, N'-methylenebisacrylamide, N, N'-tetramethy-lenebisacryamide and divinylbenzene as crosslinkers, respectively, they were varied with the crosslinked poly(4-vinyl pyridines) containing different crosslinkers. These results were discussed in terms of the properties of the crosslinkers.

• Polymer(Korea)
• /
• v.24 no.5
• /
• pp.610-620
• /
• 2000

Vinyl acetate (VAc) was polymerized at 30, 40, and 5$0^{\circ}C$ using 2,2'-azobis (2,4-dimethylvaleronitrile) (ADMVN) and tertiary butyl alcohol (TBA) as the initiator and the solvent, respectively. High molecular weight (HMW) atactic poly(vinyl alcohol) (PVA) was prepared by saponifying the poly(vinyl acetate) (PVAc) synthesized. The effect of polymerization conditions were investigated in terms of conversion, degree of branching for acetyl group of PVAc, and molecular weight of both PVAc and PVA. The polymerization rate of VAc in TBA was proportional to the 0.49th power of ADMVN concentration in good accordance with the theoretical value of 0.5. HMW-PVA with high yield could be obtained successfully, probably due to lower polymerization temperature and decreased chain transfer reaction rate which was achieved by adopting ADMVN and TBA. PYAc having average degree of polymerization (P$_{n}$) of 10000~13000 was obtained at the conversion of 35~70%. Saponification of so prepared PVAc yielded PVA having P$_{n}$ of 2400~6100. The syndiotactic diad content increased with decreasing polymerization temperature and increasing VAc concentration due to a steric hindrance effect of TBA during polymerization.

• Polymer(Korea)
• /
• v.38 no.3
• /
• pp.307-313
• /
• 2014

The physical properties of functionalized graphene sheet (FGS)/poly(ethylene-co-vinyl acetate) (EVA) was examined with various kinds of EVA, having vinyl acetate (VA) contents in the range of 0 to 40 wt%. The compatibility between FGS and EVA was enhanced as the polar VA content of EVA increased. Thus, the dispersion of FGS in EVA became finer, and the decrease of surface resistivity and the increase of tensile modulus by the added FGS became more effective when the VA content of EVA was high. When the VA content was low, the elongation at break was reduced drastically by added FGS due to the poor adhesion of FGS/EVA interface. The crystallization of EVA was generally retarded by the interaction with dispersed FGS. However, when both the VA content of EVA and the added amount of FGS were low, the crystallization of EVA was enhanced, probably due to the predominant nucleating effect by FGS.

• Korean Journal of Plant Resources
• /
• v.12 no.3
• /
• pp.179-185
• /
• 1999

The study which was conducted to determine the effects of the polyethylene film on the culture of Pleurotus ostreatus is summarized in the following: 1) The fresh weight of Pleurotus ostreatus cultured by the box culture method mulching with black polyethylene film was 2,237g/box and, 2,028g/box by white polyethylene film mulching, and 1,695g/box at the conventional culture which was by 24.2% and 16.4% higher than that of the conventional culture.2) The fresh weight of P. ostreatus cultured by the shelf culture method mulching with the black polyethylene film was 17.4kg/m$^2$ at the white polyethylene film culture, 14.6kg/m$^2$ at the conventional culture which was by 16.2%, 7.5% higher than that of the conventional culture. 3) The best shape appearance in terms of the diameter in P. ostreatus was 5~30mm and the intervals were 10cm respectively. 4) The black polyethylene film mulching in P. ostreatus observed in good protection against Pseudomonas spp., Trichoderma, or mushroom flies. 5) The black polyethylene film mulching method for the culture of P. ostreatus was much better than that of the shelf-culture, box-culture or the sack culture in terms of total yield and quality. 6) The length of harvesting implement of P. ostreatus was suitable for 45~120cm in order to use on the harvest of the mulching.

• Horticultural Science & Technology
• /
• v.30 no.4
• /
• pp.437-441
• /
• 2012

This study was conducted to find out the optimum container for increasing acclimatization rate of in vitro mass propagated plantlets of Ever-bearing strawberry (Fragaria ${\times}$ ananassa Duch.) via bioreactor. Four types of containers were used such as transparent plastic container (TPC), plug tray (PT), I-pot (IP), and black vinyl pot (BVP). Number of date maintaining soil water content above 10% was five days in TPC, three to four days in BVP, two days in PT, and one day in IP. Survival rate of plantlets was 80% in BVP, 70% in TPC, 55% in IP, and 15% in PT. In TPC, growth increment of plantlets was the greatest among all the tested containers and the lowest in IP. Numbers of runner per plant were 3.3 in BVP, 2.9 in TPC, 1.6 in PT, and 1.2 in IP. Total cost was 44,405,300 won/10 a in BVP, resulting in reducing more 6,659,400 won/10 a than IP's (51,064,700 won/10 a). Around 102,718 plants/10 a were produced by using BVP, suggesting that 30,265.1 plants/10 a more could be produced than IP (72,452.9 plants/10 a). Production cost per plant was 432.3 won in BVP, resulting in reducing 272.5 won than IP's (704.8 won). As a result, BVP was appropriate for acclimatization of in vitro plantlets through bioreactor system.