• Applied Biological Chemistry
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• v.28 no.2
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• pp.68-75
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• 1985

Laboratory experiments were conducted to investigate the effect of compost and humic acid treatment on adsorption of Cd, Zn, and Cu in soils. Three soils differing in physical and chemical properties used in this experiments were Bonyrang (Typic Udifluvents) SL, Gangseo (Aquatic Eutrochrepts) L, and Gyorae (Typic Distrandepts) SiL. Adsorption of Cd, Zn, ana Cu on the soils followed Langmuir isotherm up to 75 ppm of initial concentration. The adsorption maxima of Cd, Zn, and Cu for the Bonryang soil, the lowest in pH, organic matter content, and CEC, were the lowest of the three soils. Although the Gyorae soil derived from volcanic ash was the highest in organic matter content and CEC, the adsorption maxima of heavy metals for the Gyorae soil were lower than those for the Gangseo soil of which organic content and CEC were intermidiate. The adsorption maxima/CEC ratios for the Bonryang, the Gangseo, the Gyorae soils were found to be in the range of $23{\sim}27%,\;28{\sim}57%$, and $11{\sim}14%$ respectively The bonding energy constants of Cd, Zn, and Cu for the soils were in the order of Gangseo>Bonryang>Gyorae soils. The adsorption maxima of Cd, Zu, and Cu for the Bonryang soil increased with compost treatment by $100{\sim}210%,\;90{\sim}230%$, and $130{\sim}290%$ respectively, while little difference was observed when the soil was treated with humic acid Bonding energy constants of Cd, Zn, and Cu for the Bonryang soil increased significantly with compost treatment, and showed insignificant correlation with humic acid treatment.

• Korean Journal of Organic Agriculture
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• v.22 no.3
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• pp.503-519
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• 2014

This study was conducted to investigate ginger growth and its nutrient uptake depending on changes of soil properties as affected by applications of green manure crop and/or charcoal in continuous cropping system. The green manure crops applied were barley and hairy vetch, and charcoal was additionally treated in selected plots as a soil conditioner. Experimental plots were prepared as Plot 1 (control), Plot 2 (barley of 8kg $10a^{-1}$), Plot 3 (hairy vetch of 12kg $10a^{-1}$), Plot 4 (charcoal of 1,000kg $10a^{-1}$ and barley 8kg $10a^{-1}$), and Plot 5 (charcoal of 1,000kg $10a^{-1}$ and hairy vetch of 12kg $10a^{-1}$) with two different soil conditions (high clay content, HCC and low clay content, LCC). When comparing selected chemical properties of soils before and after cultivating ginger plant, soil pH decreased from 6.9~8.1 to 6.8~7.6, and electrical conductivity (EC) also declined from $0.45{\sim}1.25dSm^{-1}$ to $0.30{\sim}0.61dSm^{-1}$. However, the content of soil organic matter (SOM) and total nitrogen (T-N) increased. Thus, the soil chemical properties were improved with the applications of green manures and charcoal. Also, macro- and micro-nutrient contents of ginger plants in the different plots were various between normal and diseased plants grown in soils with HCC and LCC. In particular, the concentration of manganese (Mn) was 3~4 folds higher in the diseased plant than in the normal plants. Ginger growth status and yield was relatively improved with the applications of green manures and charcoal as comparing with control plot. Especially in the Plot 4 with LCC, the ginger plant was not infected by root-rot disease.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.6
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• pp.454-459
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• 2007

This experiment was conducted to investigate the effect of long-term continuous application of fertilizers for rice cultivation from 1954 to 2003. Changes of physical and chemical properties of paddy soil and the rice yield by continuous application of fertilizers, particularly rice straw compost, over fifty years were discussed in this paper. The rice yields of compost applied plots were 5~12% higher while those of no fertilizer plots were 21~38% lower compared to those of NPK fertilizers applied plots. Uptakes of T-N, $P_2O_5$, $K_2O$, CaO, MgO, and $SiO_2$ by rice plants were significantly increased by the application of straw compost. Bulk density, hardness, and liquid phase of soil in compost applied plots were significantly decreased while gaseous phase and cation exchange capacity (CEC) of soil were increased compare to those in NPK plots. When the bulk density of soil was increased the rice yield was decreased. The soil organic matter (SOM) content tended to increase in compost applied plots whereas no significant differences were found in other treatments. The soil organic matter content increased by $0.4g\;kg^{-1}\;yr^{-1}$ when $7.5Mg\;ha^{-1}\;yr^{-1}$ of rice straw compost applied in paddy land. The compost application rate recommendation for rice cultivation in Korea could be revised by the results of this study.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.3
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• pp.27-39
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• 2009

The main objective of this study is to investigate the characteristics of combustion by analyzing fuel gases from a combustion equipment with various combustion conditions for refuse-derived fuels (RDFs). CO gas is a parameter for indicating of incomplete combustion during a combustion process. The lowest CO gas was produced when the experiment conditions were m=2 under air-fuel condition and $800^{\circ}C$. $CO_2$ gas is a final product after complete combustions. The highest amount of $CO_2$ gas was produced when the experiment conditions were m=2 under air-fuel condition and $800^{\circ}C$. The highest level of $SO_2$ gas was produced in S.1 sample containing the highest sulfur. The highest level of NOx gas was produced in S.1 sample with the highest nitrogen content and air-fuel condition of m=2 under temperature of $800^{\circ}C$. HCl gas that is generated by reacting with metals catalyst through oxygen catalyst reaction during combustion process is a precursor of dioxin formation. The higher level of HCl gas was produced in the sample with higher chlorine content. The lowest level of HCl gas was produced when the experiment conditions were air-fuel condition of m=2 and $800^{\circ}C$. The lowest level of $NH_3$ gas was generated when the experiment condition was m=2 under air-fuel condition and after 3 minutes. Air-fuel condition is more important to create $NH_3$ gas than operating temperatures. Higher level of $H_2S$ gas was generated in S.1 sample with the higher sulfur content and was created in RDFs that contain higher mixture ratios of sewage sludge and food wastes. A result of combustion, gases and gases levels from the combustion of S.1 and S.2 were very similar to the combustion of a stone coal. As results of this research, when evaluating the feasibility of the RDFs, the RDFs could be used as auxiliary and main fuels.

• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.1
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• pp.29-34
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• 2008

This experiment was conducted to study the effects of growth stage and variety on the quality of whole crop rice(WCR) silage at National Institute of Animal Science, RDA from 2004 to 2005. Two types of rice("Chucheong" for food and "Hamasari" for whole crop) were harvested at six different growth stages (heading, flowering, milk, dough, yellow ripen and fully ripen stage) and ensiled each harvest stages. Crude protein(CP) content of all whole crop rice silage was also decreased with progressed maturity at harvest and TDN(total digestible nutrient) content of WCR was increased. The average CP content of whole crop rice was higher than that of food rice. The contents of ADF(acid detergent fiber) and NDF(neutral detergent fiber) decreased with delayed harvest maturity. The content of TDN estimated from ADF content was increased with progressed maturity, but there was not found significant difference between rice varieties(p<0.05). The average pH value was 4.69 and it was increased with delayed harvest maturity. Acetic and butyric acid content were decreased, but lactic acid content was increased with progressed maturity. The experiments presented here show that all rice varieties may give a good quality silage. But some wrong practical method(grain loss, productivity, nutrient value, etc.) will make poor quality of rice silage. Therefore, dough stage of harvest maturity will be recommendable as proper harvest time for making high quality of whole crop rice silage in Korea.

• Microbiology and Biotechnology Letters
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• v.7 no.1
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• pp.37-46
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• 1979

In order to investigate the compositional change of the lauan and pine sawdust media during the coltivation of oyster mushroom (Pleurotus ostreatus) chemical components of the two media and mushroom were analized periodically from spawning to ending. The results are summerized as follows: 1) The total yield of mushroom from the lauan sawdust media was 6.39 kg/$m^2$, and from the Pine saw-dust media 6.31 kg/$m^2$, 94％ of which was produced from the first and second cropping period. 2) In both media ash content increased gradually, while organic matter content decreased as the cultivation progressed. Moisture content, which was about 79％ at the time of spawning, decreased a little during the priod of mycelial propagation, after which no change was observed. 3) Total nitrogen content of the two media decreased gradually as the cultivation progressed, and total loss of insoluble nitrogen was greater than that of soluble nitrogen. Amino nitrogen content tended to increase continually. 4) In both media pentosan, $\alpha$-cellulose, lignin and C/N ratio decreased gradually, while the content of reduced sugar, trehalose and mannitol continued to increase. 5) In both media phosphorus, potassium, manganese and zinc decreased, and magnecium, calcium, iron and copper showed irregular changes. 6) CMC-saccharifying and liquefying activity gradually increased from after mycelial propagation to the second cropping, after which it decreased in both media. Xylanase activity rapidly and greatly increased during the second cropping period rather than the first period. At the start of the third cropping period the activity decreased slowly. Protease activity was highest after mycelial propagati, after which it gradually decreased. The pH of the two media decreased as the cultivation progressed. 7) In both media little change was observed in the content of the components of mushroom cropped from the first to the third period, but slight decrease was noticed at the fourth cropping.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.45-50
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• 2017

We investigated effect of Zn content on shear strengh of Sn-0.7Cu-xZn and OSP surface finished solder joints. Five pastes of Sn-0.7Cu-xZn (x=0, 0.5, 1.0, 1.5, 2.0 wt.%) solders were fabricated by mixing of solder powder and flux using planatary mixer. $180{\mu}m$ diameter solder balls were formed on OSP surface finished Cu electrodes by screen print method, and the reflow process was performed. The shear strength was evaluated with two high shear speeds; 0.01 and 0.1 m/s. The thickness of the intermetallic compound(IMC) layer was decreased with increasing Zn content in Sn-0.7Cu-xZn solder. The highest shear strength was 3.47 N at the Zn content of 0.5 wt.%. As a whole, the shear strength at condition of 0.1 m/s was higher than that of 0.01 m/s because of impact stress. Fracture energies were calculated by F-x (Force-displacement) curve during high speed shear test and the tendency of fracture energy and that of shear strength were good agreement each other. Fracture took place within solder matrix at lower Zn content, and fracture occured near the interface of OSP surface finished Cu electrode and solder at higher Zn content.

• The Korean Journal of Food And Nutrition
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• v.13 no.6
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• pp.578-584
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• 2000

Three kinds of the mashes of 15%, 20% and 25% of boiled wax gourd containing 20% of sugar were fermented by yeast at 5~1$0^{\circ}C$ for 100 days. After fermentation, total sugar content of the 15% mash was 8.0%, 20% mash 8.6%, and 25% mash 8.3%, respectively. Also, it revealed that in reducing sugar content, 15% mash was 7.4%, 20% mash 7.6%, and 25% mash 7.4%, respectively, In protein content, 15% mash was 10.3mg/ml, 20% mash 9.8mg/ml, and 25% mash 11.3mg/ml, and in amino acid content, 15% mash was 0.13 $\mu$mo1/ml, 20% mash 0.03 $\mu$mo1/ml, and 25% mash 0.03 $\mu$mo1/ml, each. In case of pH, 15% mash was 3.88, 20% mash 3.99, and 25% mash 3.97, respectively. In acidity, 15% mash was 0.37, 20% mash 0.44. and 25% mash 0.43, respectively. In the number of yeast cell, 15% mash was 8.33 logCFU/ml, 20% mash 8.56 logCFU/ml, and 25% mash 8.57 logCFU/ml. respectively. In ethanol content, 15% mash was 13.4%, 20% mash 14.9%, and 25% mash 15.5%, respectively. In organic acid content, acetic acid, pyruvic acid, citric acid, and lactic acid were produced, and succinic acid content ranges from 1,407~1,800 mg/l. Five-grade scoring test of sensory evaluation showed that in its taste degree, 15% mash was 3.93, 20% mash 3.66 and 25% mash 3.40, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.293-293
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• 2014

Over last decade InGaN alloy structures have become the one of the most promising materials among the numerous compound semiconductors for high efficiency light sources because of their direct band-gap and a wide spectral region (ultraviolet to infrared). The primary cause for the high quantum efficiency of the InGaN alloy in spite of high threading dislocation density caused by lattice misfit between GaN and sapphire substrate and severe built-in electric field of a few MV/cm due to the spontaneous and piezoelectric polarizations is generally known as the strong exciton localization trapped by lattice-parameter-scale In-N clusters in the random InGaN alloy. Nonetheless, violet-emitting (390 nm) conventional low-In-content InGaN/GaN multi-quantum wells (MQWs) show the degradation in internal quantum efficiency compared to blue-emitting (450 nm) MQWs owing higher In-content due to the less localization of carrier and the smaller band offset. We expected that an improvement of internal quantum efficiency in the violet region can be achieved by replacing the conventional low-In-content InGaN/GaN MQWs with ultra-thin, high-In-content (UTHI) InGaN/GaN MQWs because of better localization of carriers and smaller quantum-confined Stark effect (QCSE). We successfully obtain the UTHI InGaN/GaN MQWs grown via employing the GI technique by using the metal-organic chemical vapor deposition. In this work, 1 the optical and structural properties of the violet-light-emitting UTHI InGaN/GaN MQWs grown by employing the GI technique in comparison with conventional low-In-content InGaN/GaN MQWs were investigated. Stronger localization of carriers and smaller QCSE were observed in UTHI MQWs as a result of enlarged potential fluctuation and thinner QW thickness compared to those in conventional low-In-content MQWs. We hope that these strong carrier localization and reduced QCSE can turn the UTHI InGaN/GaN MQWs into an attractive candidate for high efficient violet emitter. Detailed structural and optical characteristics of UTHI InGaN/GaN MQWs compared to the conventional InGaN/GaN MQWs will be given.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.11
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• pp.1638-1648
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• 2016

This study was conducted to analyze the quality characteristics of kimchi in terms of garlic content (0~4.5%). Kimchi was made at $4^{\circ}C$ for 8 weeks, and pH, acidity, organic acid content, free sugar content, microbial counts, flavor pattern, and sensory characteristics were measured. The results show that kimchi containing garlic had a higher pH and lower acidity during fermentation than control kimchi without garlic. Principal component analysis enabled differentiation of the flavor pattern of kimchi according to fermentation period and garlic content. Addition of garlic to kimchi significantly decreased the numbers of total bacteria and lactic acid bacteria for 2 weeks after production. The numbers of total bacteria and lactic acid bacteria increased rapidly up to 2 weeks during fermentation and thereafter decreased gradually. Coliform counts were higher in the control than in kimchi containing garlic, whereas there was no detection after 4 weeks. Yeast and mold counts decreased significantly with increasing garlic content during the initial fermentation stage. Counts could not be detected in kimchi containing garlic. After 4 weeks, counts could not be detected in kimchi without garlic. Among kimchi with different garlic contents, fermentation was slower in kimchi with high garlic content; scores for off-odor and off-note taste were lower as well.