• Applied Chemistry for Engineering
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• v.27 no.4
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• pp.444-448
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• 2016

Hollow silicon/carbon (H-Si/C) composites as anode materials for lithium ion batteries were investigated to overcome the large volume expansion. H-Si/C composites were prepared as follows; hollow $SiO_2\;(H-SiO_2)$ was prepared by adding $NaBH_4$ to $SiO_2$ synthesized using $st{\ddot{o}}ber$ method followed by magnesiothermic reduction and carbonization of phenolic resin. The H-Si/C composites were analyzed by XRD, SEM, BET and EDX. To improve the capacity and cycle performance, the electrochemical characteristics of H-Si/C composites synthesized with various $NaBH_4$ contents were investigated by charge/discharge, cycle, cyclic voltammetry and impedance tests. The coin cell using H-Si/C composite ($SiO_2:NaBH_4=1:1$ in weight) in the electrolyte of $LiPF_6$ dissolved in organic solvents (EC : DMC : EMC = 1 : 1 : 1 vol%) has better capacity (1459 mAh/g) than those of other composition coin cells. It is found that the coin cell ($SiO_2:NaBH_4=1:1$ in weight) has an excellent capacity retention from 2nd cycle to 40th cycle.

• Applied Chemistry for Engineering
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• v.26 no.5
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• pp.543-548
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• 2015

Si/C/CNF composites as anode materials for lithium-ion batteries were examined to improve the capacity and cycle performance. Si/C/CNF composites were prepared by the fabrication process including the synthesis and magnesiothermic reduction of SBA-15 to obtain Si/MgO by ball milling and the carbonization of phenol resin with CNF and HCl etching. Prepared Si/C/CNF composites were then analysed by BET, XRD, FE-SEM and TGA. Among SBA-15 samples synthesized at reaction temperatures between 50 and $70^{\circ}C$, the SBA-15 at $60^{\circ}C$ showed the largest specific surface area. Also the electrochemical performances of Si/C/CNF composites as an anode electrode were investigated by constant current charge/discharge test, cyclic voltammetry and impedance tests in the electrolyte of LiPF6 dissolved in mixed organic solvents (EC : DMC : EMC = 1 : 1 : 1 vol%). The coin cell using Si/C/CNF composites (Si : CNF = 97 : 3 in weight) showed better capacity (1,947 mAh/g) than that of other composition coin cells. The capacity retention ratio decreased from 84% (Si : CNF = 97 : 3 in weight) to 77% (Si : CNF = 89 : 11 in weight). It was found that the Si/C/CNF composite electrode shows an improved cycling performance and electric conductivity.

• Journal of Life Science
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• v.10 no.3
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• pp.273-278
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• 2000

The chemical compositions as amino acids, minerals, fatty acids, and total polyphenolic compounds of the seeds of leek (Allium tuberusum) were analyzed. The antioxidative activity of water soluble extract from leek seeds was also tested in DPPH ($\alpha$, $\alpha$ - diphenyl-$\beta$ -picrylhydrazyl) method. The chemical compositions of leek seeds were moisture 4.4%, curde protein 25.7%, crude fat 16.6%, and crude ash 2.9%. Major amino acid compositions were proline 11 g, glutamic acid 4.9 g, arginine 2.1g, aspartic acid 1.6g, leucine 1.3g, valine 1.2 g, and methionine 1.1 g as per 100g. Mineral contents were K 215 ppm, Ca 142 ppm, Fe 124 ppm, and Mg 100 ppm. Major fatty acid compositions were linoleic acid 71.9%, oleic acid 12.7%, palmitic acid 8.6%, and stearic acid 1.4%. The changes of contents in polyphenolic compound from leek seeds caused by heat treatment were also listed in the following order; $20^{\circ}C$(364mg/100g), $40^{\circ}C$(462 mg/100g), and $60^{\circ}C$(551 mg/100g). Antioxidative activity as electron donating ability showed in the following order; 0.05% BHT(butylated hydroxytoluene)(45.6%)>0.05% water-extract(31.3%)>0.1% water extract(30.3%). On the basis of chemical analysis, the leek seedsshowed to have relatively high contents of nutrients as amino acids, minerals, fatty acids.

• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.842-849
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• 2012

The purpose of this study is to determine the possibility of using Agarum cribrosum as a natural health food source. To accomplish this purpose, the contents of the general and antioxidant activities of Agarum cribrosum were measured. The contents of carbohydrate, crude protein, crude lipid and ash were 45.4%, 15.0%, 2.3% and 33.1%. The calories of Agarum cribrosum were 262.3 kcal and total dietary fiber of Agarum cribrosum was 34.0%. The protein contained a total of 18 different kinds of amino acids. The content of amino acids was 12,402.42 mg/100 g. The K was the largest mineral followed by Ca, Na and Mg, implying that Agarum cribrosum is an alkali material. The antioxidant activity of Agarum cribrosum was assessed by various radical scavenging assays using DPPH (2,2-diphenyl-1-picrylhydrazyl), FRAP (ferric ion reducing antioxidant power), reducing power, and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)). All antioxidant activity of Agarum cribrosum extract increased the concentration of the dependents. Total phenolic contents of Agarum cribrosum extract were $34.1{\pm}2.56mg/g$, and total flavonoids contents were estimated at $4.9{\pm}0.26mg/g$. General nutrients and other antioxidant bioactive materials in Agarum cribrosum were also potential materials for good health food. It is expected that a follow-up study of Agarum cribrosum through developing processed food and evaluation of their functional properties would provide useful information or sources of functional foods.

• Korean Journal of Environmental Agriculture
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• v.17 no.3
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• pp.189-194
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• 1998

In order to evaluate the residual effects of bituminous coal fly ash, gypsum, oyster shell as soil amendments, Chinese cabbage was cultivated on acidic sandy loam soils with low boron content. The soils were amended in the upper 15cm with amendments in previous year and the growth and qualities of plants were analyzed. Amendments treated one year before were, in metric tons per hectare, i) none(Check) ; ii) 80 fly ash(FA) ; iii) 4 shell(SH) ; iv) 56 fly ash + 24 gypsum (FG) ; v) 40 fly ash + 24 gypsum + 0.8 shell(FGS). Yield response in fresh weight of Chinese cabbage was in order of 834% for FGS > 780% for FG > 755% FA > 193% for SH plants. Reducing sugar, vitamin-C, and total nitrogen contents of leaves depending on treatments showed the same tendencies as that in yields, whereas crude fibre opposite to them. In particular, FA, FG, and FGS plants showed normal growth without both boron deficiency symptoms which appeared in Check and SH plants and possibilities of accumulation of heavy metals. In any soils treated with the above amendments, however, magnesium was insufficient.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.779-786
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• 2012

Many farmers have been seeking alternatives to chemical fertilizer for successful organic fruit production. This experiment was carried out to investigate the replaceability of chemical fertilizer by cover crop and slurry composting biofiltration (SCB) liquid manure (LM) application in pear orchard. Three treatments were contained in this experiment; cover crop only and cover crop + LM treatment, and control (chemical fertilizer application). Dry weight and mineral contents of gramineous cover crops were significantly increased in LM-combined treatments than that of leguminous species. Bulk density of soil was decreased in rye + LM and hairy vetch + LM treatments, compared with each cover crop treatment. Soil pH was lowest in fertilizer treatment and soil nitrate content became similar between treatments after rainy season. Available soil phosphate was lower in cover crop and cover crop + LM treatmemts than control, but exchangeable Mg was higher. The mineral content and net assimilation rate of leaves showed no difference between the treatments. As a result, it is suggested that the application of SCB liquid manure in pear orchard managed by cover crops is desirable to maintain the productivity by improving soil physical properties and potential nutrient recovery.

• Food Science and Preservation
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• v.21 no.3
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• pp.388-395
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• 2014

Six types of mixed cereals powder were prepared using different mixing ratios of barley, proso millet, sorghum, and adlay, and their nutritional components and functionalities were analyzed. The mixed cereals powders contained high levels of crude protein. The free amino acid and mineral contents of Sample E were the highest among all the samples. Fructose, glucose, sucrose, and maltose were detected as the four major free sugars in all the mixed cereals powders, and Sample D had the highest amount of reducing sugar among all the samples. The total polyphenol and total flavonoid contents of Sample F were significantly higher than those of the other samples. Sample C showed the highest level of DPPH radical scavenging activity and reducing power. As for the ABTS radical scavenging activity, the $IC_{50}$ of Sample D was the lowest among all the samples, but did not significantly differ from that of Sample C. Therefore, we suggest 2:2:1:1 (in Sample D) as the best mixing ratio of barley, proso millet, sorghum, and adlay to produce a mixed cereals powder with excellent nutritional value and antioxidant activities.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.164-164
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• 2017

해양환경 중 많이 사용되는 철강재료들은 그 가혹한 부식환경에 대응하기 위하여 일반적으로 피복 도장방식법이나 음극방식법이 적용되고 있다. 여기서 음극방식법은 선박 및 해양구조물의 해중부 부식에 대해 가장 효과적인 방식법으로 알려져 있다. 한편, 이와 같이 해수 중 철강재에 음극방식을 적용할 경우, 피방식체인 그 강재 표면에 해수 중 용존된 산소의 음극환원 반응이 일어나며 국부적인 알카리 표면 조건을 형성시켜 $Mg(OH)_2$와 $CaCO_3$의 막을 석출시킨다. 이와같이 음극방식 중 형성된 전착물은 방식해야 될 표면적을 감소시켜 방식전류밀도를 감소시키는 효과가 있는 것으로 보고되고 있다. 이렇게 석출된 전착물은 음극표면에 부분적으로 형성되고, 여러 가지 환경 조건 등의 영향을 받아 그 피막의 형성 정도도 가늠하기 어렵기 때문에 음극방식 설계 시 그 정도에 따른 영향을 고려-반영하기가 곤란하다. 또한 이 전착물은 그 형성 메커니즘에 관한 해석이나 강도, 균일한 밀착성, 장기적인 방식효과 및 효율성 등이 아직 충분히 입증되어 있지 않은 실정에 있다. 따라서 본 연구에서는 해수 중 다양한 전착 프로세스에 의해 제작된 전착물의 기간별, 도장코팅 종류별 특성변화를 분석 및 평가하고, 전착물에 의한 희생양극 소모전류 변화 측정 분석을 통해 전착막을 균일하고 치밀하게 형성시키기 위한 최적의 조건을 찾고자 하였다. 또한 석출속도, 밀착성 및 내식특성을 향상시키기 위해 해수 중 기체를 용해시켜 제작한 막의 특성을 분석-평가하였다. 본 연구에 사용된 강 기판은 일반구조용강(KS D 3503, SS400)으로 ${\varnothing}42.7{\times}1,000mm{\times}4.0t$의 형상으로 제작하였다. 인가된 전류밀도는 1, 3 및 $5A/m^2$이고 도장 코팅 종류별 전착 석출물의 형성차이 비교 분석을 위한 실험은 선박 및 해양구조물에 많이 사용되는 Universal Epoxy 도료 2종을 선정하여 진행하였다. 또한 Steel Wire Mesh의 영향을 알아보기 위해 Mesh를 설치하여 실험을 진행하였다. 기간별-도장 종류별 외관관찰, 전착물의 두께 측정, SEM, EDS 및 XRD를 통해 막의 모폴로지, 조성원소 및 결정구조를 분석하였으며, 전착물의 내식성과 내구성을 평가하기 위해 테이핑 테스트(Taping Test) 및 전기화학적 양극분극 시험을 실시하였다. 희생양극 소모율에 대한 전착물의 영향을 확인하기 위해 외부전원을 인가하여 전착 피막을 형성시킨 강 기판에 희생양극을 연결하여 희생양극 소모효율 측정 시험을 진행하였다. 전착물의 석출량은 시간 및 전류밀도의 증가에 따라 비례하여 증가하였으며, 음극전류 인가 시 금속과 용액 계면 사이의 확산층에서 발생한 $OH^-$ 이온으로 인해 금속과 용액 계면 사이 pH가 부분적으로 증가하여 $Mg(OH)_2$ 화합물이 많이 생성되는 것으로 확인되었다. 또한 Mesh의 부착으로 평활하지 않게 형성된 미세한 굴곡구조 및 표면적 증가로 인하여 단계적으로 피복되는데 필요한 시간이 지연되면서 $CaCO_3$에 비해 $Mg(OH)_2$ 화합물이 상대적으로 증가한 것으로 사료된다. $CaCO_3$(Aragonite) 구조는 견고한 피막으로 치밀하고 화학적 친화력이 높아 우수한 밀착성을 보였으며 전착물의 영향으로 양극 전류가 감소하였고, 이로인해 방식전류 절감효과를 얻을 수 있을 것으로 기대된다.

• Korean Journal of Environmental Agriculture
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• v.17 no.2
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• pp.164-169
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• 1998

In order to evaluate the utility of the bituminous coal fly ash, gypsum, oyster shell as soil amendments, acid sandy loam soil with low boron content were amended in the upper 15cm with amendments, and then chinese cabbage was cultivated in fall. Amendments treated were, in metric tons per hectare, i ) none(Check) ; ii) 80 fly ash(FA) ; iii) 4shell(SH) ; iv) 56 fly ash+24gypsum (FG) ; v) 40 fiy ash + 24 gypsum +0.8 shell(FGS). On the whole, amendments imoroved soil chemical properties and contents of N, P, K, Ca, and B in leaves. Among treatmens, FA prominently neutralized soil pH and increased available $P_2O_5$ ,B but decreased Fe contents in soils. FGS also affected the increment of exchangeable Ca, Mg, and available B. Yield response in fresh weight of chinese cabbage was in order of 85% for FGS>77% for FG>66% FA>5% for SH plants. Reducing sugar and vitamin-C contents of leaves depending on treatments showed the same tendencies as that in yields, whereas crude fiber opposite to theme. In particular, FA, FG, and FGS plants showed normal growth without boron deficiency symotoms which appeared in Check and SH plants.Taken together, FGS was an effective combination enable to maximize the utility of fly ash, gypsum, and shell as soil amemdments, especially in cabbage yield and quality.

• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.65-69
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• 1998

In order to evaluate the utility of bituminous coal fly ash, gypsum, oyster shell as soil amendments, aadic clayloam paddy soils with low calaum content were amended in the upper 15㎝ with amendments, and then Chinese cabbage was cultivated under plastic film house. Amendments treated were, in metric tons per hectare, i) none(Check) ; ii) 80 fly ash(FA) ; iii) 4 shell(SH) ; iv) 56 fly ash+24 gypsum (FG) ; v) 40 fly ash+24 gypsum+0.8 shell(FGS). On the whole, soil chemical properties were improved by amendments treatments. Amongst treatments, FA prominently neutralized soil pH and increased contents of Av. $P_2O_5$, Ex. K, and Av. B in soils. Besides, it showed the highest ratio in bacteria/fungi and (bacteria+actinomycetes)/fungi. FGS also affected the neutralization of soil pH and the increment of Ex. Mg. Amendments plants appeared alkaline damages only at early growing stage, but showed positive responses in fresh weight yields : 23% for FGS : 21% for FG : 19 18% for SH. At harvesting, leaves both of FA and FGS plants had higher values in contents of N, P, K, Ca, Mg, Fe, Mn, Zn, B, reduang-sugar, and vitamin-C than of others. In especial, Check plants appeared the heart rot symptoms owing to calaum defiaency differently from amendments plants. Taken together, FGS was an effective combination enable to maximize the utility of fly ash, gypsum, shell as soil amendments, espeaally in cabbage yield and quality.