• Korean Journal of Environmental Agriculture
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• v.31 no.1
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• pp.1-8
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• 2012

BACKGROUND: Organic fertilizers in watermelon cultivation are widely used to supply nutrient and organic matter. This study was conducted to investigate the effects of application rate of organic fertilizer on the watermelon growth and soil chemical properties in greenhouse METHODS AND RESULTS: The organic fertilizers used in this experiment were mixed expeller cake (MEC) and mixed organic fertilizer (MOF). The treatments were conducted with 4 levels (1.0 N, 0.7 N, 0.5 N and 0.3 N) on the basis of soil testing nitrogen fertilization (STNF) using MEC or MOF as the basal dressing, and using chemical fertilizers (CF) as the additional dressing on the rest of STNF. These fertilizations were compared to CF 1.0 N (0.3 N as the basal and 0.7 N as the additional dressing) and non fertilization (NF). The leaf area of watermelon in treatment 0.5 N and 0.3 N using MEC or MOF was similar to CF treatment. The absorbed nutrient amounts by leaf, weight and sugar contents of fruit in the 0.5 N and 0.3 N treatments were higher than other treatments. In 0.5 N and 0.3 N treatments using MEC or MOF on the basis of STNF, soil chemical properties such as electrical conductivity (EC), available $P_2O_5$ and exchangeable K concentrations after experiment showed tendency to decreasing or similar level before experiment. CONCLUSION(s): These results suggest that the MEC or MOF application as the basal dressing at the 30~50% level of STNF and CF application as the additional dressing on the rest of STNF be best to maintain adequate nutrient of soil and to increase marketable yield for watermelon.

• Journal of the Korean Chemical Society
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• v.13 no.3
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• pp.209-214
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• 1969

The experiment have been carried out for the determination of aggregation state of isopolytantalate anion in aqueous solution by using "Ultracentrifuge Method". The molecular weight of this anion at pH 10.7 could be determined as a heptatantalate anion $Ta_7O_{22}^{9-}$.

• Bulletin of the Korean Chemical Society
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• v.22 no.9
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• pp.945-947
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• 2001

The He-Xe interaction potential has been determined using a direct inversion of the experimentally reduced-viscosity collision integrals obtained from the corresponding states correlation. The potential is in a good agreement with the previously determined potential. The potential predicts viscosity and diffusion coefficients and they are found to be in a good agreement with experiment.

• Bulletin of the Korean Chemical Society
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• v.22 no.10
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• pp.1076-1080
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• 2001

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.228-232
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• 2002

The rise throughput and the stability in the device fabrication can be obtained by applying chemical mechanical polishing(CMP) process in 0.18 ${\mu}m$ semiconductor device. However it does have various problems due to the CMP equipment. Especially, among the CMP components, process variables are very important parameters in determining removal rate and non-uniformity. In this paper, We studied the DOE(design of experiment) method for the optimized CMP process. Various process variations, such as table and head speed, slurry flow rate and down force, have investigated in the viewpoint of removal rate and non-uniformity. Through the above DOE results, we could set-up the optimal process parameters.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.148-148
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• 2017

Surface modification is a type of mechanical manipulation skills to achieve extensive aims including corrosion control, exterior appearance, abrasion resistance, electrical insulation and electrical conductivity of substrate materials by generating a protective surface using electrical, physical and chemical treatment on the surface of parts made from metallic materials. Such surface modification includes plating, anodizing, chemical conversion treatment, painting, lining, coating and surface hardening; this study conducted cavitation experiment to assess improvement of durability using anodizing. In order to observe surface characteristics with applied current density, the electrolyte temperature, concentration was maintained at constant condition. To prevent hindrance of stable growth of oxide layer due to local temperature increase during the experiment, stirring was maintained at constant speed. In addition, using galvanostatic method, it was maintained at processing time of 40minutes for 10 to $30mA/cm^2$. The cavitation experiment was carried out with an ultra sonic vibratory apparatus using piezo-electric effect with modified ASTM-G32. The peak-to-peak amplitude was $30{\mu}m$ and the distance between the horn tip and specimen was 1mm. The specimen after the experiment was cleaned in an ultrasonic bath, dried in a vacuum oven for more than 24 hours, and weighed with an electric balance. The surface damage morphology was observed with 3D analysis microscope. As a result of the study, differences were observed surface hardness and anti-cavitation characteristics depending on the development of oxide film with the anodizing process time.

• Design & Manufacturing
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• v.13 no.3
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• pp.48-52
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• 2019

As the consumer market in the mold, automation and aerospace industries grows, the demand for chemical machining using on electrochemical polishing increases. To enhance the surface roughness and gloss of the micro-needle, we have studied for an electrochemical polishing. Electrochemical polishing requires the chemical reaction of solution and material according to the electrolyte and electrode. In this study, sulfuric acid(30%), phosphoric acid(50%), and DI-water(20%)were used as the electrolytic solution, and the electrolytic solution temperature used $58^{\circ}C$. Electrochemical polishing was carried out in experimental conditions, and the micro-needle experiment was carried out from the basic experiment to obtain the experimental conditions. Experimental results show that as the voltage and current increase, the surface roughness improved and the gloss is improved. So, the best result for this experiment was obtained in condition 6, which improved micro-needle.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.1
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• pp.85-91
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• 1994

This experiment was conducted to obtain the basic information of the major chemical components for breeding high quality varieties of sweet potatoes [Ipomoea batatas (L) Lamk]. Six recommended varieties were cultivated at the experimental plots of Hwasung and Suwon in 1992. Starch value. glucose, fructose, maltose, and sucrose content were analyzed with time intervals during storage period. Starch value of Shinyulmi was the highest among six varieties in both locations. Glucose and fructose contents were appeared wide variations in varieties and locations. Shinyulmi showed the highest maltose content and Yulmi had the highest sucrose content in two locations. Total sugar contents were higher in Shinyulmi and Yulmi. Starch value, glucose, fructose, maltose, and sucrose content were stable during storage period, however these were differed between locations.

• Korean Journal of Medicinal Crop Science
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• v.22 no.6
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• pp.483-488
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• 2014

Lime-bordeaux mixture (LBM) has been used instead of pesticides in ginseng field and orchard since the 1960's in Korea. In this experiment, LBM was made with different concentrations and sprayed in the field of ginseng for eco-friendly cultivation. Growth characteristics and disease such as alternaria blight, anthracnose, and gray mold were investigated in 4-5 year old ginseng after spraying LBM. LBM caused a little damage on leaf when it was sprayed at the time of leafing stage, late April and early May. Root weights of five-year-old ginseng were 43.1~51.5 g and 41.2~46.6 g in the plot of mid-April and mid-May treatments, respectively. These growth levels were further reduced as compared with that of the chemicals treatment plot. The rate of diseases in the plot of 6-6 and 8-8 ratio were 0.0~4.8% and 0.0~4.4%, respectively, which was similar with that in the plot of chemical control for alternaria blight and anthracnose. However, LBM had little effect on controling gray mold. It showed lower control effect in the plot of 4-4 ratio than that of chemical control. This result will be expected to be a useful guide that can be used in the field to the farmers of the ginseng.

• Proceedings of the Korean Society of Tobacco Science Conference
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• 1998.10a
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• pp.15-15
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• 1998