• Journal of the Korea Organic Resources Recycling Association
• /
• v.11 no.3
• /
• pp.87-95
• /
• 2003

Although extensive studies were conduced on hydrogen fermentation of organic wastewaters, little is known about biohydrogen production from organic solid wastes. The leaching-bed reactor treating food waste by heat-shocked anaerobic sludge was, therefore, operated at D of 2.1, 3.6, 4.5 and $5.5d^{-1}$ to find optimal D for hydrogen production. Successful operation of a reactor can be accomplished when it is operated at proper dilution rate (D). Operation at high D leads to the washout of biomass in the reactor while operation at low D leads to product inhibition due to the accumulation of excess VFA. These appear to limit the production of hydrogen to reach a higher level. All the reactors showed that, on day 1-3, hydrogen production was dominant and VFA concentration was higher than ethanol. Butyrate and acetate were major components of VFAs over the whole operation, though lactate was very high on day 1-2. Compared with other D values, D of $4.5d^{-1}$, resulted in higher butyrate/acetae (B/A) ratios during the fermentation. The trend of B/A ratios was similar to the hydrogen production, suggesting that butyrate formation favored hydrogen production. Ethanol increased significantly from day 4 when hydrogen Production stopped. It indicated that heat-shocked sludge was able to induce a metabolic flow from hydrogen-and acid-producing pathway to solvent-producing pathway. Operation at D of $4.5d^{-1}$ led to higher fermentation efficiency (58%) than those (51.5, 55.3 and 53.7%) at 2.1, 3.6 and $5.5d^{-1}$. The COD removed was convened to hydrogen (10.1%), VFA (30.9%), and ethanol (17.0%).

• Korean Journal of Organic Agriculture
• /
• v.19 no.3
• /
• pp.343-355
• /
• 2011

This work was studied the effects of spore density and infection of arbuscular mycorrhizal fungi (AMF) for no-tillage organic cultivation of pepper with wintering green manure crops cultivation in greenhouse field. Spore density of arbuscular mycorrhizal fungi (AMF) in green manure crops was 189 spores/30g fresh soils in control including alive spore (82 spores). Spore density of AMF in all green manure crops was totally 196~226 spores/30g fresh soil and alive spore was 84~112 spores/30g fresh soil. Spore density of AMF in soils of Pepper crop was range of 48.0~56.7 spores/30g fresh soils after cultivation of green manure crops. Infection structure of AMF was not significantly difference in soils of green manure crops and Pepper crop after cultivation of green manure crops. Infection rate of AMF in roots of green crops was low level by 2.8% in giant chickweed, 7.4% in rye, 9.3% in hairy vetch. Infection rate of AMF in roots of barley was the highest level by 20.3%. Infection rate of AMF in roots of Pepper crop was range of 5.2~7.2% after cultivation of green manure crops Also, infection rate of AMF in roots of Pepper crop was 8.1% after the harvest of barley. Infection structure of AMF in barley very well consisted of network with internal hyphae, while hairy vetch and rye tended to no network. There was not a significant relationship between spore density in soils and infection rate of AMF in rhizosphere of Pepper.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.13 no.3 s.55
• /
• pp.127-134
• /
• 2009

This study investigated their properties of spalling resistance and residual compressive strength after fire test corresponding to various ISO, RABT heating curves, and contents of hybrid organic fiber of high strength concrete. The results were summarized as following. As fundamental characters of concrete with hybrid organic fiber, the flowability was directly declined as the increase of fiber contents, and air contents were decreased or increased a little bit, but there was not big difference. The compressive strength was gradually declined sluggishly at 28 days. As properties of fire resistance, in case of RABT heating curves, compare with ISO heating curves a spalling aspect showed till range that has much contents of hybrid organic fiber, but they are mostly peeling spalling, which means spalling aspect didn't happen to inside. In conclusion, in case of W/B 25% high strength concrete, the spalling was prevented over 0.04% of contents of fiber at ISO heating curve and over 0.10% of contents of fiber at the RABT heating curve. In case of spalling was prevented, mass reduction rate according to the change of heating temperature curves showed around 7% at ISO heating curves and around 9% at RABT heating curves. The residual compressive strength rate corresponding to the change of heating temperature curves showed 50%~60% at ISO heating temperature curves and 30%~35% at RABT heating temperature curves in case of spalling was prevented.

• Food Science and Preservation
• /
• v.20 no.1
• /
• pp.23-29
• /
• 2013

To extend the shelf-life of freshly cut lotus roots, the effect of their heat treatment in water at $50^{\circ}C$ was investigated and compared with that of their treatment using 1 percent ascorbic acid and citric acid during their storage. In addition, consecutive heat and acid treatment was applied to freshly cut lotus roots to determine its synergy effect. The level of molds in the sample that was treated with $50^{\circ}C$ water for 60 minutes was the lowest among the treatments and 3.89 log CFU/g after 12-day storage, whereas the population of the control was 6.81 log CFU/g for the same number of days. During the storage, the surface color of the samples showed higher ${\Delta}E$ values and lower L values than that of the initial sample. The color with the heat treatment hardly changed, unlike in the control. The consecutive treatments with hot water and acid showed less quality loss than the simple heat treatment. The marketable quality was maintained for three days without any treatment, for nine days with the heat treatment, and for 12 days with the consecutive treatments of hot water and acid. The consecutive treatments with hot water and acid, especially with 1 percent citric acid, extended the shelf-life of the freshly cut lotus roots by inhibiting the growth of microorganisms and the browning.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2000.02a
• /
• pp.103-103
• /
• 2000

강한 결정 방향 의존성과 낮은 항정계를 갖는 Bi4Ti3O12 강유전체 박막은 NDRO형 비휘발성 강유전체 메모리 분야에서 매우 유망한 재료이다. 이를 위해서는 실리콘 기판과의 계면조절과 실리콘 기판성에서 고품질의 강유전성 박막을 성장시키는 기술이 필수적이다. MOCVD에 의한 Bi4Ti3O12 의 증착에서는 Bi 성분의 강한 휘발 특성과 낮은 반응성으로 인하여 조성과 두께 등의 조절이 매우 어렵다. 따라서 화학기상증착의 기구를 이해하고 제어하는 기술이 양질의 박막을 얻는데 필수적이다. 본 연구에서는 유기금속 원료 TPB, TIP 과 산소를 이용하여 실리콘 기판위에 Bi4Ti3O12 강유전체 박막을 증착할 때, 증착 변수의 변화에 따른 박막의 증착 거동과 구조적, 전기적 특성을 연계하여 분석하였다. 특히 기판부착력이 낮고 휘발성이 강한 Bi의 특성으로 인한 문제를 개선하기 위하여 TIP원료를 주기적으로 공급, 중단을 반복하는 펄스주입법을 고안하여 그 효과를 살펴보았다. 실리콘 기판위에서 TiO2의 증착속도는 실험온도 영역에서 온도에 따라 변화하지 않는 전형적인 물질 전달에 의해 지배되는 양상을 나타내었다. 반면 Bi2O3 경우에는 50$0^{\circ}C$ 이상에서 급격하게 증착속도가 감소하는 특이한 경향을 나타내었으며 이는 Bi2O3의 높은 휘발성 때문일 것이다. Bi4Ti3O12 박막은 온도증가에 따라 증착속도가 증가한 후 $600^{\circ}C$ 이상에서 포화되는 경향을 보였다. 이로부터 실리콘 기판위에서의 Bi4Ti3O12 박막의 증착 모델을 제시하였다. Bi2O3에 비해 상대적으로 표면 부착력이 월등히 큰 TiO2가 우선적으로 실리콘 펴면에 형성된 후 TPB 유기금속 원료가 이 TiO2와 반응하는 과정으로 Bi4Ti3O12 박막이 증착된다. $600^{\circ}C$이상에서는 증착 변수들을 바꾸어도 물성이 변하지 않는 자기조절기능이 있음을 알 수 있었는데 이는 고온에서의 Bi2O3의 강한 휘발성 때문일 것이다. 실리콘 기판에서 층상 페로브스카이트 상은 58$0^{\circ}C$ 이상에서 형성되며, 매우 좁은 온도 변화에도 결정구조, 박막현상 및 성분이 크게 바뀌는 온도에 민감한 증착거동이 관찰되었다. 증착 모델에서 예견되는 Bi의 불리함을 개선하기 위해 펄스주입법을 실시한 경우 Bi의 성분량이 증가되었고 결정성이 향상되었다. 이로부터 펄스주입법이 박막내에 부족하기 쉬운 Bi를 보충하여 박막의 특성을 개선함을 확인하였다. Bi4Ti3O12 박막의 증착온도에 따른 누설전류 특성 측정 결과 증착온도가 감소할수록 누설전류가 감소함을 알 수 있었고 펄스주입법이 연속주입법보다 더 낮은 누설전류를 보임을 알았다. 펄스주입법의 경우 -2.5V 인가 시의 누설전류는 7.4$\times$10-8A/cm2에서 1.3$\times$10+7A/cm2의 매우 우수한 값을 가졌다. 연속 주입법에 의해 증착된 박막은 C-V 측정 결과 강유전성 이력이 나타나지 않았으나, $600^{\circ}C$ 이상에서 펄스주입법에 의해 증착된 박박은 강유전성 이력을 나타내었다.

• Korean Journal of Environmental Agriculture
• /
• v.10 no.1
• /
• pp.1-10
• /
• 1991

The object of this stduy was to investigate the pollution of Pb in paddy field soil with different distance from roadside and to find out the relationship between the ratio of chemical fractions of total Pb and soil characteristics. Lead from automobiles is exhausted as particulates composed primarily of halide compounds (PbBrCl, $PbBr_2$, $PbCl_2$). The samples of soil were collected directly from the paddy fields with different distance from the roadside of highway and expressway which are located in Kyungpook province. A sequential extraction procedure was used to fractionate Pb in paddy field soil into the disignated forms of water soluable, exchangeable, organically bounded, carbonate, sulfide, and residual Pb. Results obtained are summerized as follows. 1. The content of Pb in paddy field soil was the highest in Chungdo, 30.0 ppm, the lowest in Koryung, 14.8 ppm, and the total average content was 21.9 ppm. The effect of traffic volume was not clear, but a slight difference according to the order of opened year of roads was showed. 2. The effect of distance from roadside was not clear. The content of Pb in paddy field soil with different distance from roadside was 22.2 ppm within l0m, 22.1 ppm in 10∼30m, 22.2 ppm in 30∼50m. and 21.3 ppm beyond 50m. 3. The distribution of Pb fractions in soil showed a wide difference depending on soil properties. The average content of exchangeable. organically bounded, carbonate, sulfide, and residual Pb was 8.6%, 33.6%, 29.8%, 21.5%, and 6.7%, of total Pb in the soil, respectively. 4. The content of organically bounded Pb in soil showed highly positive correlation with organic matter and CEC, while the content of exchangeable Pb was highly negative correlation. 5. With higher soil organic matter and CEC, organically bounded Pb fraction tend to be higher but exchangeable Pb fraction tend to be lower. Other forms of Pb showed no difference with soil organic matter contend and CEC. The distribution of Pb fraction related to CEC showed similiar tendency with that of organic matter content.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.7
• /
• pp.848-856
• /
• 2017

This study aimed to investigate the effect of rice nuruk prepared from rice with different degrees of milling (0, 10, 30, 50, and 70%) on physicochemical qualities of yakju. The results indicated significant differences in the qualities of yakju prepared using rice nuruk from rice with different degrees of milling. Specially, pH, amino acidity, brownness, b value, and color difference were significantly reduced as the degrees of milling increased, whereas contents of alcohol and volatile acid, reducing sugar, and L value were increased. Malic acid, succinic acid, and lactic acid were the main organic acids in yakju, and there were significant differences among the treatments in malic acid, lactic acid. However, there was no tendency according to different degrees of milling. In addition, contents of total free amino acids and nitrogen compounds showed no tendency according to degrees of milling, whereas the content of aspartic acid showed a tendency to decrease significantly. The content of 2-phenyl alcohol in the volatile flavor components showed a tendency to increase significantly with higher degree of milling of rice nuruk, whereas contents of n-propanol and iso-amyl alcohol tended to decrease significantly.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 2002.11a
• /
• pp.128-131
• /
• 2002

향 관련 직업을 중심으로 한 연구에는 유기 화학적 냄새에 폭로된 종사자를 대상으로 그들의 작업환경 개선을 주된 목적으로 실시되어져왔으나 천연향 자극에 대한 연구는 전무한 상태이다. 본 연구에서는 화장품 관련 전문직과 화장품 판매직을 대상으로 100%의 basil oil, lavender oil, lemon oil, jasmine oil, ylang-ylang oil (KIMEX co. Ltd, Korea), skatole (TAKASAO co. Ltd, Japan)등 6종 향 자극에 대한 EEG, 주관평가에 대해 알아보았다. 그 결과, 전문직에서 선호도가 높은 향은 Fz와 F3에서, 선호도가 낮은 향은 P4에서 $\alpha$/$\beta$비가 증가하는 경향을 나타냈다. 상호 정보량에 대해서는 두 직업 모두 선호도가 낮은 향에 대한 상호 정보량이 선호도가 높은 향에 비해 더 많았다. 특히 화장품 관련 전문직에서는 전두엽의 상호 정보량이 증가하는 경향이 확인되었다. 이상에서 판매직과 비교하여 전문직은 천연향 자극이 감성효과가 아닌 외부자극에 대한 고차원적 기능을 담당하는 전두엽 영역과 관련된 지성효과로 작용함을 알 수 있었다.

• Korean Journal of Organic Agriculture
• /
• v.24 no.4
• /
• pp.747-758
• /
• 2016

Quality characteristics, such as moisture content, pH, acidity, sugar content, salinity, flavor, taste, color, and overall acceptance of apple Jangachi prepared with different apple cultivars were investigated after different times in storage. The initial moisture content of apple Jangachi was 14.19-16.94% according to cultivar. After 5 days of storage, the moisture content increased to 23.26-26.91%. The pH was 3.98-4.55 regardless of cultivar. Total acidity decreased at first and then increased slightly after 10 days in the range of 0.8% to 1.3%. The sugar content of apple Jangachi decreased from 60-68% to 27-34% on the 5th day and was maintained at 23-25% after 5 days regardless of apple cultivar. The salinity of apple Jangachi increased from 0.94-1.64% to 3.5-3.8% after 15 day regardless of cultivar. In the sensory evaluation, apple Jangachi prepared with the Gala cultivar was given the best ratings in overall acceptability.

• Korean Journal of Organic Agriculture
• /
• v.22 no.4
• /
• pp.645-656
• /
• 2014

The aim of this study was to evaluate the product quality and function properties of hot pepper (green and red) fruits cultivated by organic and conventional agricultural practices. Organic and conventional hot peppers were analyzed their product quality with respect to pH, soluble solid, hardness, and color values. The soluble solid contents of organic hot peppers were 2.6~10% higher but their hardness was slightly lower than those of conventional hot peppers. Hot peppers were further analyzed their functional properties on chlorophyll contents, ASTA (American Spice Trade Association) value, total phenolics, and SEM ultrastructure. In case of green pepper, organic hot pepper showed higher (-)a value and the significantly (p<0.001) higher amounts of chlorophyll a and b than conventional hot pepper. Interestingly, organic red hot pepper showed higher (+)a value than that of conventional one. The ASTA value of organic red hot pepper was 28% higher than that of conventional one. Regardless of the fruits color, total phenolics content of organic hot peppers was more enriched than those of conventional ones. These results suggest that organic hot peppers exhibited more excellent color quality and functional properties than conventional hot peppers regardless of fruit color.