• 한국식품조리과학회지
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• 제20권6호
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• pp.667-676
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• 2004

The purpose of this study was to estimate the microbial quality of some raw vegetables, and suggest a safer method for their sanitization and pre-preparation in foodservice operations. Baechu-geotjeori was monitored from the ingredient to the final product, during different holding temperature. Three sanitization methods were performed during the pre-preparation (tap water, chlorine water and electrolyzed water). The largest reduction in the microbial counts was shown with the electrolyzed water pre-preparation (after treatment; the total plate counts decreased to 3.34-4.06 Log CFU/g, coliform counts decreased to 1.40-1.45 CFU/g). Prior to immersion in the chlorine water, washing was first peformed to see if the was a larger effective reduction in the microbial counts.

• 대기
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• 제24권4호
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• pp.533-540
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• 2014

Statistical forecast models for the prediction of the summertime Changma precipitation have been developed in this study. As effective predictors for the Changma precipitation, the springtime sea surface temperature (SST) anomalies over the North Atlantic (NA1), the North Pacific (NPC) and the tropical Pacific Ocean (CNINO) has been suggested in Lee and Seo (2013). To further improve the performance of the statistical prediction scheme, we select other potential predictors and construct 2 additional statistical models. The selected predictors are the Northern Indian Ocean (NIO) and the Bering Sea (BS) SST anomalies, and the spring Eurasian snow cover anomaly (EUSC). Then, using the total three statistical prediction models, a simple ensemble-mean prediction is performed. The resulting correlation skill score reaches as high as ~0.90 for the last 21 years, which is ~16% increase in the skill compared to the prediction model by Lee and Seo (2013). The EUSC and BS predictors are related to a strengthening of the Okhotsk high, leading to an enhancement of the Changma front. The NIO predictor induces the cyclonic anomalies to the southwest of the Korean peninsula and southeasterly flows toward the peninsula, giving rise to an increase in the Changma precipitation.

• Journal of Biosystems Engineering
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• 제30권4호
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• pp.195-201
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• 2005

The output of Stirling engine is influenced by the regenerator effectiveness. The regenerator effectiveness is influenced by heat transfer and flow friction loss of the regenerator matrix. In this paper, in order to provide a basic data for the design of regenerator matrix, characteristics of heat transfer and flow friction loss were investigated by a packed method of matrix in the oscillating flow as the same condition of operation in a Stirling engine. As matrices, several kinds of combined wire screen meshes were used. The results are summarized as follows; The packed meshes with high mesh no. in the side of heater part of regenerator showed effective than the packed meshes with low mesh no. in the side of cooler part of regenerator. The temperature difference and pressure drop of the regenerator were not made by the specific surface area of wire screen meshes but by the minimum free-flow area to the total frontal area. Among the No. 150 single screen meshes, 200-60 combined meshes, the 200-150-100 combined meshes showed the highest in effectiveness.

• 한국미생물·생명공학회지
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• 제26권1호
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• pp.40-44
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• 1998

토양으로부터 갈락토스 전이활성이 우수한 $eta$-galactosidase를 생산하는 미생물을 분리하고 부분동정하여 한국종균협회에 Penicillium sp. KFCC 10888로 등록하였다. 효소는 40% 유당 용액에서 초기 유당의 73%가 전환되었을 때 70%의 높은 전이율을 보였다. 효소의 생합성은 유당에 의하여 유도되지 않았으며 배지성분으로는 콩가루가 효소 생산에 효과적이었다. 효소의 갈락토스 전이반응에 대한 최적 pH는 4.0, 최적온도는 55$^{\circ}C$이었으며, 55$^{\circ}C$에서 열안정성이 우수하였다. 갈락토올리고당의 생성량은 기질의 농도에 비례하였으며, 40%유당용액의 경우 갈락토올리고당의 함량은 고형분중 40%까지 향상되었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.20-20
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• 2000

Back-propagation neural network (BPNN) is the most prevalently used paradigm in modeling semiconductor manufacturing processes, which as a neuron activation function typically employs a bipolar or unipolar sigmoid function in either hidden and output layers. In this study, applicability of another linear function as a neuron activation function is investigated. The linear function was operated in combination with other sigmoid functions. Comparison revealed that a particular combination, the bipolar sigmoid function in hidden layer and the linear function in output layer, is found to be the best combination that yields the highest prediction accuracy. For BPNN with this combination, predictive performance once again optimized by incrementally adjusting the gradients respective to each function. A total of 121 combinations of gradients were examined and out of them one optimal set was determined. Predictive performance of the corresponding model were compared to non-optimized, revealing that optimized models are more accurate over non-optimized counterparts by an improvement of more than 30%. This demonstrates that the proposed gradient-optimized teaming for BPNN with a linear function in output layer is an effective means to construct plasma models. The plasma modeled is a hemispherical inductively coupled plasma, which was characterized by a 24 full factorial design. To validate models, another eight experiments were conducted. process variables that were varied in the design include source polver, pressure, position of chuck holder and chroline flow rate. Plasma attributes measured using Langmuir probe are electron density, electron temperature, and plasma potential.

• Journal of the Korean Wood Science and Technology
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• 제42권2호
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• pp.172-182
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• 2014

Extraction is a necessary element in the bioconversion of lignocellulosics to fuels and chemicals. Although various forms of chemical pretreatment of cellulosic materials have been proposed, their effectiveness varies depending on the treatment conditions and substrate. In this study, mixed hardwood (MH) and loblolly pine (LP) were pretreated with dilute acid in a 100 mL accelerated solvent extraction (ASE) at the predetermined optimal conditions: temperature: $170^{\circ}C$, acid concentration: 0.5% (w/v), and reaction time: 2~64 min. This method was highly effective for extracting the hemicellulose fraction. Total xmg (defined as the sum of xylose, mannose, and galactose) can be extracted from milled MH and LP through pressurized dilute acid treatment in maximum yields of 12.6 g/L and 15.3 g/L, respectively, representing 60.5% and 70.4% of the maximum possible yields, respectively. The crystallinity index increased upon pretreatment, reflecting the removal of the amorphous portion of biomass. The crystalline structure of the cellulose in the biomass, however, was not changed by the ASE extraction process.

• Journal of Welding and Joining
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• 제3권2호
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• pp.42-51
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• 1985

The dynamic fracture toughness, fracture characteristics, impact tension and tensile properties of Al-Mg-Si T5 alloy and Al-Zn-Mg T6 alloy respectively welded with filler metal of Alcan 4043 were investigated. The dynamic fracture toughness values were obtained rapidly and simply for the specimen of small size by using instrumented Chirpy impact testing machine. the testing temperatures of the specimen were a range of room temperature and-196.deg. C. The results obtained in this experiment are summarized as follows. With decreasing the testing temperatures, dynamic tensile stress and fracture load were increased, on the other hand the deflection and impact value showed decreasing tendency in order of base metal>HAZ>weld. Changes of total absorbed energy were more influenced by the crack propagation energy than the crack initiation energy. At the low temperatures, the unstable rapid fracture representing the crack propagation appeared for the specimens of Charpy press side notched in Al-Zn-Mg alloy, but it was difficult to obtain the unstable rapid fracture in Al-Mg-Si alloy. Because of the development of plastic zone at the notch root, it was difficult to obtain thevalid $K_{1d}$ value in Al-Mg-Si alloy. Therefore the fatigue cracked specimens were effective in both Al-Mg-Si and Al-Zn-Mg alloys. With decreasing the impact testing temperatures, specimens underwent a transition from dimple-type transgranular fracture to lamella surface-type intergranular fracture because of the precipitate at the grain boundaries, impurities and crystal structure of the precipitates.s.

• 한국식품위생안전성학회지
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• 제10권4호
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• pp.263-270
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• 1995

In order to promote the prevention of microbial and enzymatic spoilage and to retain the freshiness, sweet persimmons harvested in Gyeongsangnam-do were treated with graperfruit seed extract(GFSE)-CaCO3 mixture and stored in the proper packaging conditions. A low concentration of GFSE showed effective growth inhibition of plant pathological bacteria and fungi, Enterobacter pyrinus and Fusarium sp., which were involved in the decay of fruits and vegetables. GFSE was stable to heat treatment; its antimicrobial activity was not changed by heat treatment upto 10$0^{\circ}C$. However, when the temperature was raised to 12$0^{\circ}C$, about 90% of total activity was retained within 30 min. GFSE was also highly stable to broad pH changes; its activity was not changed in the range of pH 2.0 to pH 12.0. The physiological function of cell membrane in the spores of Bacillus cereus and the hyphae of Fusarium sp. was destroyed by treating with GFSE. It was observed that treating sweet persimmons with GFSE minxture and storing them in strech-wrapped packages could prolong the greshness of sweet persimmons and reduce quality deterioration.

• 대한영양사협회학술지
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• 제9권4호
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• pp.273-277
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• 2003

The purpose of this study was to examine sanitation management practices of restaurant managers for the training needs analysis. A total of 26 restaurant managers participated in this study. A check list was consisted of three parts : facility, personal, and food hygiene. Two observers and one manager evaluated the same check list at same time and the results were compared. The results of this study suggested that most restaurants have needed for re-training programs in the view of facility, personal, food sanitation practices. Specially, proper washing and sanitizing methods for hands and utensils, proper cooking and holding temperature, and proper storing methods were needed to be trained. Based on this study, most independent restaurant managers in Cheonan were aware of training, but they had no effective training program manuals. Results of this study implicated that dietitians have new opportunity for consultants of independent restaurants in the region because they have practiced sanitation management manuals.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.274-277
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• 2009

There have been a number of works on manufacturing ultrafine grained steels with average ferrite grain sizes of smaller than a few micrometers to develop beneficial high strength steels. Among microstructures in low carbon steels, lath martensite is known to be useful to produce an ultrafine grained ferrite matrix and finely globular cementite particle. Thus, severe plastic deformation and subsequent annealing at lower temperature of lath martensite would become an effective way to produce ultrafine grained steels. However, most ultrafine grained steels exhibited a total elongation of a few per cent in tensile tests. Such a defect is one of the primary factors restricting the potential applications of ultrafine grained steels. Therefore, the improvement of the strength-elongation balance is required for the application of ultrafine grained structural steels. In this study, the effect of deformation temperatures on microstructure, such as ferrite grain size and the distribution of cementite particles, and mechanical property of lath martensite steels, was investigated. Specimens were fabricated through cold rolling or warm rolling and subsequent annealing.