• Journal of the Korean Society of Food Science and Nutrition
• /
• v.23 no.2
• /
• pp.315-321
• /
• 1994

In order to prevent the postharvest decay and to promote the freshness retention of fruits and vegetables grapefruit seed extract(GFSE), natural microorganism control agent, was applied to the preservation of fresh fruits and vegetables. Freshfruits and vegetables treated with GFSE and stored in polyethylene film (0.1mm) at 1$0^{\circ}C$-15$^{\circ}C$ of natural low temperature low kept better qualities in color and texture than the GFSE -not- treated control. The treatment using GFSE ina 250ppm to 500ppm concentration seemed to be an effective one for the control of Botrytis cinerea isolated in red wine grapes. After 4 weeks of storage the firmness rate of cucumbers treated with the dilute GFSE was four times higher than that of non-treated ones. GFSE showed effective inhibitory action towards plant pathological bacteria and fungi which were involved in the decay of fruits and vegetables. Minimum inhibitory concentrations of GFSE towards them were in the range of 250ppm to 500ppm .Direct visualization of microbial cells and spores using electron microscopy showed microbial cells and fungal spores the function of which was destroyed by treating with the dilute solutions of GFSE. It was observed that GFSE would reduced disease damages and have bactericide & fungicide properties during the storage of such fruits and vegetables as egg plant, wild edible greens , kumquat, and kiwi fruit.

• Proceedings of the Korea Association of Crystal Growth Conference
• /
• 1996.06b
• /
• pp.239-257
• /
• 1996

$\beta$-BaB2O4는 고출력 가시광선 및 적외선을 발진시키는데 유용한, 비선형 특성을 가진 물질이다. $\alpha$-$\beta$ 상전이 온도가 녹는점보다 18$0^{\circ}C$ 낮기 때문에 보통 flux법으로 단결정을 성장시킨다. 수년전 Itoh등은 $\beta$-BaB2O4단결정을 congruent조성의 용액으로부터 Czochralski법으로 metastable한 상태에서 직접 성장시켰다. 그렇지만 그 공정은 잘 이해되지 않고 있으며 재현하기가 매우 어렵다. 저자들은 $\beta$-BaB2O4단결정을 용액표면온도도 1034$^{\circ}$-1085$^{\circ}C$, pulling rate 3mm/h, 10-30 rpm의 범위에서 성장시켰으며 융액표면의 온도구배는 $\beta$-상으로 성장시키는데 매우 중요한 인자로 여겨진다. Seed로는 직경 1-2mm의 c축방향 $\beta$-BaB2O4단결정 봉이 상용되어 성장방향을 조절하고 열응력을 최소화시켰다. 성장된 $\beta$-상의 단결정들은 6-fold모양을 하며 표면에 작은 비늘같은 것들이 붙어있고 중심부에 core가 있는 것을 알았다. Flux법으로 성장시킨 $\beta$-BaB2O4단결정을 사용한 seeds는 단결정 성장 및 냉각 중에 cracks이 자주 발생하였으며, boule의 cracks은 afterheater를 사용할 경우 다소 줄일 수 있었다. 성장된 단결정의 광학특성이 측정되었다.

• Journal of Sensor Science and Technology
• /
• v.19 no.3
• /
• pp.202-208
• /
• 2010

This study examined the dependency of crystalline orientation and electric properties of sol-gel PZT film on hydrolysis, a $PbTiO_3$ seed layer and a concentration of sol-gel solution. The PZT thin films were prepared by using 2-Methoxyethanol-based sol-gel method and spin-coating on Pt/Ti/$SiO_2$/Si substrates. The 1-${\mu}m$-thick PZT films were coated and then fired in a furnace by direct insert method. The highly (111) oriented PZT film of pure perovskite structure could be obtained. We could control the degree of orientation by various parameters such as hydrolysis, a $PbTiO_3$ seed layer and a concentration of sol-gel solution. The highest measured remanent polarization, dielectric constant and piezoelectric coefficient are $24.16\;{\mu}C/cm^2$, 2808, and 159 pC/N, respectively.

• Journal of the Korean institute of surface engineering
• /
• v.51 no.5
• /
• pp.263-270
• /
• 2018

Ag-coated Cu dendrites were prepared as a filler for an electromagnetic interference shielding application. Ag layers on the Cu dendrites was coated by two approaches. One is a direct autocatalytic plating with a reducing agent. The other approach was achieved by two-step plating, a galvanic displacement reaction to form Ag seed layers on Cu following by an autocatalytic plating with a reducing agent. The procedure-dependent average particle size and tap density of Ag-coated Cu dendrites were characterized. The electrical resistance and electromagnetic interference shielding effect (EMI SE) were analyzed with the Ag-coated Cu dendrites prepared in the two approaches. Additionally, the content of the Ag coated on Cu dendrites was controlled from 2% to 20%. The electrical resistance and EMI SE were critically determined by Ag contents coated on Cu.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.90.1-90.1
• /
• 2010

Due to the rapidly diminishing energy sources and higher energy production cost, the interest in dye-sensitized solar cells (DSSCs) has been increasing dramatically in recent years. A typical DSSC is constructed of wide band gap semiconductor electrode such as $TiO_2$ or ZnO that are anchored by light-harvesting sensitizer dyes and surrounded by a liquid electrolyte with a iodide ion/triiodide ion redox couple. DSSCs based on one-dimensional nano-structures, such as ZnO nanorods, have been recently attracting increasing attention due to their excellent electrical conductivity, high optical transmittance, diverse and abundant configurations, direct band gap, absence of toxicity, large exiton binding energy, etc. However, solar-to-electrical conversion performances of DSSCs composed of ZnO n-type photo electrode compared with that of $TiO_2$ are not satisfactory. An important reason for the low photovoltaic performance is the dissolution of $Zn^{2+}$ by the adsorption of acidic dye followed by the formation of agglomerates with dye molecules which could block the I-diffusion pathway into the dye molecule on the ZnO surface. In this paper, we prepared the DSSC with the ZnO electrode using the chemical bath deposition (CBD) method under low temperature condition (< $100^{\circ}C$). It was demonstrated that the ZnO seed layers played an important role on the formation of the ZnO nanostructures using CBD. To achieve truly low-temperature growth of the ZnO nanostructures on the substrates, a two-step method was developed and optimized in the present work. Firstly, ZnO seed layer was prepared on the FTO substrate through the spin-coating method. Secondly, the deposited ZnO seed substrate was immersed into an aqueous solution of 0.25M zinc nitrate hexahydrate and 0.25M hexamethylenetetramine at $90^{\circ}C$ for hydrothermal reaction several times.

• The Plant Pathology Journal
• /
• v.18 no.2
• /
• pp.68-73
• /
• 2002

The influence of fungicidal spray was assessed on powdery mildew epidemics caused by Erysiphe polygoni D.C. and on yield-attributing characters of mungbean [Vigna radiata (L.) Wilczek]. Mildew attack adversely affected the yield-attributing characters of mungbean and exhibited negative significant correlation with pod length (-0.57), pods/plant (-0.74), pod weight (-0.68), 100 seeds weight (-0.69), 100 seeds swell weight (-0.59), and seed germination (-0.71). These characters had direct or indirect effects on grain yield, which was also adversely affected due to mildew attack (-0.89). Powdery mildew was significantly retarded due to the single spray of carbendazim (0.05%) at 30-day-old crop, where the apparent rate of infection (r) was minimum at 0.0095/ unit/day and with low (11.44%) powdery mildew intensity. Other fungicides like tridemorph (0.075%) and penconazole (0.05%) were equally effective against the mildew disease where the disease intensity was less than 20% and the values of r were 0.0134 and 0.039/unit/day respectively, as compared with the control at 0.267/unit/day. Fungicide spray influenced the yield-attributing characters besides controlling the disease. Such effects were more pronounced in carbendazim (0.05%)-treated plots due to its phytotonic nature where pod length (7.59cm), pods/plant (29.75), pod weight (8.16 g), 100 grain weight (3.94 g), and swell weight of 100 seed (9.49 g) were maximum resulting to the highest yield (480 kg/ha) as compared with that of control (224 kg/ha). Spray of carbendazim also improved seed germination (74.5%). Spray of other fungicides like carbendazim with copper oxychloride in 1:1 ratio, tridemorph (0.075%), and penconazole (0.05%) was equally effective against powdery mildew of mungbean. These fungicides also exhibited positive effects on yield-attributing characters of the crop and finally increased yield. These systemic fungicides were more effective in controlling powdery mildew disease of V. radiata in the rainy season compared with wettable sulphur.

• Korean Journal of Weed Science
• /
• v.2 no.2
• /
• pp.141-145
• /
• 1982

In order to determine the possibility of reducing rice injury caused by CNP and butachlor application, the effects of IAA seed presoaking on CNP and butachlor action against early growth of rice seedlings were investigated under flooded direct-seeding and dry-seeded conditions. CNP and butachlor injury to rice was reduced by soaking rice seeds at 0.1, 1.0 and 10ppm of IAA solution for 36 hours before seeding under flooded condition and thus shoot length and dry weight of rice seedlings increased compared with those of IAA untreated seedlings. IAA seed pretreatment also overcame the inhibitory effect of CNP and butachlor under dry-seeded condition. Effect on reducing rice injury by IAA pretreatment was more remarkable when CNP applied under dry seeded condition and butachlor under flooded condition.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.45 no.1
• /
• pp.50-54
• /
• 2000

The elongation of mesocotyl and coleoptile plays important roles in the seedling emergence and stand establishment of dry direct-seeded rice. Experiments were carried out to elucidate the effects of seed-presoaking treatments of GA$_3$ and some inorganic salts on the mesocotyl, and coleoptile elongation of rice. Seed-soaked GA$_3$ promoted the elongation of mesocotyl, but little effect on the coleoptile elongation. The stimulation effects of GA$_3$ were found to be enhanced by addition of CaCl$_2$ However, the sole treatment of CaCl$_2$ showed no stimulating effect on the mesocotyl and coleoptile elongation. Mesocotyl elongation was most prominent in the combined treatments of 50ppm GA$_3$ with 100 mM CaCl$_2$. The synergistic effects of GA$_3$ and CaCl$_2$ on mesocotyl elongation varied with varietal groups. The stimulating effects of GA$_3$ were enhanced significantly by the addition of CaCl$_2$ in japonica varieties, Dongjinbyeo, Ilpumbyeo and Milyang 95, and tall indica variety, Labelle, but not in semidwarf Tongil type varieties, Tongilbyeo, Milyang 23, and Nampungbyeo, and semi-dwarf indica, Short Labelle. The promoting effects of GA$_3$ on the mesocotyl elongation were decreased in proportion to the lowered osmotic potential by PEG 6000 on the contrary to CaCl$_2$ This implies that the synergistic effects of CaCl$_2$ with GA$_3$ on mesocotyl elongation was not caused by osmotic potential lowered by CaCl$_2$ addition but by the salt itself. Salts such as Ca(NO$_3$)$_2$, MgCl$_2$ BaCl$_2$, NaCl, KCl and KNO$_3$ showed the synergistic effects with GA$_3$ on mesocotyl elongation as well. The degree of synergistic effects showed no differences among salts tested, implying that there is no specificity of ions constituting the salts.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.34 no.3
• /
• pp.296-302
• /
• 1989

The mesocotyl elongation, having much effect on emergence and stand establishment in the direct sowing culture of rice, was investingated and summarized as follows: As to origin of cultivars, the average lengths of mesocotyl were 9.6 mm in the Indica-Japonica hybrid cultivars, 4.4 mm in the native cultivars and 3.2mm in the Japonica type, respectively. The mesocotyl lengths were tjereh, aman, aus, boro and bulu in order, with the mesocotyl lengths of 29.3mm and 5.4 mm in tjereh and bulu, respectively. The mesocotyl lengths were great in Baekkyungjo, Dadajo & Hejo among the native cultivars, in Sangpungbyeo, Paltal & Gokyangdo of the Japonica type and in Weonpungbyeo, Gayabyeo, Milyang 30 & Sujeongbyeo in Indica- Japonica hybrid cultivars, respectively. The mesocotyl length was the greatest at the seeds sampled I week after flowering (39. 3mm in length), and became decreased with the longer grain-filling. The mesocotyl elongated worse with the longer duration of seed storage regardless of seed maturity, and became longer at the 5$^{\circ}C$ storage plot than at the 15 and 25$^{\circ}C$ plots.

• Korean Journal of Organic Agriculture
• /
• v.27 no.1
• /
• pp.1-16
• /
• 2019

The questionnaire survey was conducted on 225 farmers in Gyeonggi-do, Jeollanam-do and Jeollabuk-do. A total of 189 (84%) farmers responded. 72% of the respondents were males, 50.3% were aged 60 or older, and 51.3% had less than 5 years of farming experience. 78.8% of the respondents are pesticide-free, and 44.4% of respondents have less than 0.5 ha of farming scale. 61.4% of the cultivated crops were vegetable crops. The order of seeds and seedlings to buy was tomato (23.3%), cucumber (12.2%) and pepper (10.6%). The cost of purchasing seeds ranged from a minimum of 100,000 won to a maximum of 5 million won. 78.3% of respondents answered that they well-knew or knew about organic seeds. 78.3% of respondents answered that they knew or knew about organic seeds. Of the positive effects of mandatory use of organic seeds, 41.3% of respondents said they would increase confidence in organic certification. However, 41% of respondents who opposed the mandatory use of organic seeds said that "The strengthening of regulations will make organic agriculture more difficult." When the use of organic seeds is mandatory, 43.4% of the respondents favor direct support for the purchase of organic seeds, which should be supported politically by the state. When organic seeds were supplied, the disease resistant seeds (53.4%) was the preferred characteristic of organic seeds. For the optimal price of organic seeds, 38.6% of respondents wanted the same price as the commercialized conventional seed. In this study, the questionnaire was conducted for three major organic farming regions, but many of the respondents were judged to have a legal position on the mandatory use of organic seeds. Therefore, the results of this study can be used as a basic data for reviewing the legislation on the organic seed production and distribution suitable for the situation of Korean organic farming.