• 전기학회논문지
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• 제64권6호
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• pp.954-959
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• 2015

In this paper, 110kW high output density, high efficiency Permanent Magnet Synchronous Motor which can be applied on tram’s traction system is introduced, along with its output and loss characteristics. The motor model is 2pole 18slot model and its size has been reduced through the high speed for high output density. Especially, structure and retainer sleeve structure is applied to its structure, which is also appropriate for high speed rotation. This kind of structure has eddy current loss problem on the surface of rotor, which must be reduced for high output density design. This study has designed the most optimized additional design parameter in order to improve the output characteristics and efficiency of previous produced 2pole 18 slot 110kW motor model and how the width of airgap affects from the loss perspective is mainly analyzed. Finally, the analysis on the extent of the efficiency improvement effect compared to the previous model has performed through electromagnetic FEM analysis. The influence of airgap flux density distribution has also been thoroughly examined.

• 한국초전도ㆍ저온공학회논문지
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• 제9권1호
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• pp.22-26
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• 2007

Superconductor is weak in AC condition. Bifilar geometry provides a solution to reduce AC loss. Bifialr geometry is piled up or wound with more than two layers. When a layer of superconductor abuts on other layers, AC loss is affected by not only self-field, but also magnetic field induced by adjacent layers. In this study, two superconductors are piled up as a series connection so that current flows in different directions. By this method, magnetic field is cancelled. If magnetic field is cancelled, AC loss is reduced. To compare AC loss with respect to piling method, we measured the AC loss difference between the case facing each other with substrate side and the case facing with YBCO side. Measured AC loss is compared with one-way current flow single layer AC loss. In addition, we analyzed how much AC loss was increased, or reduced. All results were compared with those calculated with Norris equation. By this experiment, we concluded that distance between two wires is the important cause of AC loss. The distance between two wires affects magnetic field reduction in YBCO and induced current flow on substrate side.

• Animal Bioscience
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• 제34권6호
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• pp.1070-1077
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• 2021

Objective: An experiment was conducted to determine the appropriate fasting time prior to slaughter for broilers in floor-feed and scatter-feed mode. Methods: On 21 d since hatching, 120 Arbor Acres broilers were divided into floor-feed and scatter-feed groups, chicks from each group were further assigned to feed withdrawal treatments for 0, 4, 6, 8, and 10 h. Some resultant indicators such as carcass contamination, body weight loss, meat quality of 54-day-old broilers were measured. Results: It appears that longer feed withdrawal increased weight loss, lightness, drop loss of meat but reduced pH. A significant higher weight loss and lightness for both floor-feed and scatter-feed chicks coincided after 6 to 10 h feed withdrawal (p<0.05). pH for breast muscle at 45 min postmortem reduced when chicks of scatter-feed were fasted 6 and 10 h, while the reduction of floor-feed group occurred only in 10 h (p<0.05). A noticeable effect of feed withdrawal on drop loss occurred after 10 h fasting in scatter-feed of which drop loss were significantly higher than that for other groups including control (p<0.05). The change of contamination propensity revealed that 6 to 10 h fasting significantly reduced the likelihood of carcass contamination under both floor-feed and scatter-feed (p<0.05). Net weights of intestinal contents for gizzard were significantly reduced after feed deprived for 10 h in floor-feed and 6 and 10 h in scatter-feed (p<0.05). The decrease for whole intestine occurred after floor-feed broilers have been without feed for more than 4 h, scatter-feed broilers for more than 8 h (p<0.05). Conclusion: On the premise that poultry product properties and welfare were not significantly damaged, proper fasting time could reduce carcass contamination. Current data implied that 6 h fasting was recommendable for both floor and scatter feed pre-slaughter broilers.

• Journal of Magnetics
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• 제16권4호
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• pp.417-422
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• 2011

This paper presents the characteristics of PM eddy current loss and harmonic iron loss for PM step-skewed Interior Permanent Magnet Synchronous Motor (IPMSM) with concentrated windings and multi-layered PM under the running condition of maximum torque per ampere (MTPA) and flux-weakening control. In particular, PM eddy current loss and harmonic iron loss in IPMSM have been numerically computed with three-dimensional Finite Element Analysis (3D FEA), whereby IPMSM with concentrated windings and multi-layered PM has been designed to identify the optimized skew angle contributing to the reduced PM eddy current loss and torque ripples, while maintaining the required average torque. Furthermore, numerical investigation on PM eddy current loss and iron loss at MTPA and flux-weakening control has been carried-out in terms of PM step-skew.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 추계학술대회 논문집
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• pp.79-82
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• 2001

New electronic ballast for metal halide laws is proposed New ballast has higher efficiency than that of conventional ballast. Proposed 2 stage ballast uses low arm switch as synchronous rectifier mitch. Switch-on voltage drop is smaller than that of diode in small current(<1.5A). High arm switch is turned on in zero voltage in proposed ballast. So conduction loss and switching loss are reduced Index word - synchronous rectifier mitch, toro voltage switching, conduction loss, switching loss.

• 대한한의학회지
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• 제41권2호
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• pp.58-79
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• 2020

Objectives: The purpose of this study is to predict the weight loss by applying machine learning using real-world clinical data from overweight and obese adults on weight loss program in 4 Korean Medicine obesity clinics. Methods: From January, 2017 to May, 2019, we collected data from overweight and obese adults (BMI≥23 kg/m2) who registered for a 3-month Gamitaeeumjowi-tang prescription program. Predictive analysis was conducted at the time of three prescriptions, and the expected reduced rate and reduced weight at the next order of prescription were predicted as binary classification (classification benchmark: highest quartile, median, lowest quartile). For the median, further analysis was conducted after using the variable selection method. The data set for each analysis was 25,988 in the first, 6,304 in the second, and 833 in the third. 5-fold cross validation was used to prevent overfitting. Results: Prediction accuracy was increased from 1^st to 2^nd and 3^rd analysis. After selecting the variables based on the median, artificial neural network showed the highest accuracy in 1^st (54.69%), 2^nd (73.52%), and 3^rd (81.88%) prediction analysis based on reduced rate. The prediction performance was additionally confirmed through AUC, Random Forest showed the highest in 1^st (0.640), 2^nd (0.816), and 3^rd (0.939) prediction analysis based on reduced weight. Conclusions: The prediction of weight loss by applying machine learning showed that the accuracy was improved by using the initial weight loss information. There is a possibility that it can be used to screen patients who need intensive intervention when expected weight loss is low.

• 한국통신학회논문지
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• 제36권6B호
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• pp.642-649
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• 2011

본 논문은 다중 대역에서 동작하는 안테나를 장착한 차세대 이동통신 기지국 시스템의 도입 가능성 분석을 위해 종래의 기지국 시스템과 케이블 손실전력을 고려한 차세대 기지국 시스템의 전력 손실 및 탄소 절감효과를 분석하였다. 차세대 기지국 시스템은 옥외에 무선처리부를 설치하고, 옥내의 기저대역처리부는 광케이블로 연결하여 종래의 기지국에서 케이블로 인해 발생하는 전력손실을 없애는 구조이다. 본 연구 결과 종래의 기지국과 비교하여 동일한 서비스 커버리지 확보가 가능하고, 케이블 전력손실이 5 dB 줄어든 차세대 기지국 시스템을 도입할 경우 CDMA 20W, WCDMA 30W, WiBro 10W 기지국에서 소모하는 전력량은 연간 155,078 MWh에서 49,038 MWh로 감소시킬 수 있으며, 탄소배출량 또한 65,878 $tCO_2$에서 20,832 $tCO_2$로 절감됨을 확인하였다. 따라서 차세대 기지국 시스템은 그린 IT 기술로 이용 가능할 것으로 고찰되었다.

• Journal of Applied Biological Chemistry
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• 제55권1호
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• pp.27-34
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• 2012

Soy protein isolate (SPI)-based edible coating, with and without carboxymethyl cellulose (CMC), were used to reduce oxidative degradation of cut pork stored at $4^{\circ}C$ for 5 days. The SPI coating reduced (p<0.05) thiobarbituric acid-reactive substances (TBARS) and peroxide value (PV), compared with controls. The inhibition of TBARS and PV for SPI-coated porks with and without CMC, compared with the control was 19.1 and 23.9, and 25.7 and 37.7%, respectively. The SPI coating prevented loss of $L^*$ and $a^*$ values of porks compared to the control. The ability of the SPI coating to provide a moisture barrier for the porks was reduced (p<0.05). The SPI-coated porks with and without CMC reduced moisture loss by 37.3 and 44.6%, respectively, over the control. However, SPI coating of porks did not inhibit the growth of either total plate counts or L. monocytogenes. The result revealed that SPI can effectively be used as a natural antioxidative coating to extend quality and shelf life of pork.

• Journal of Obesity & Metabolic Syndrome
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• 제27권4호
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• pp.203-212
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• 2018

Dynamic energy balance can give clinicians important answers for why obesity is so resistant to control. When food intake is reduced for weight control, all components of energy expenditure change, including metabolic rate at rest (resting energy expenditure [REE]), metabolic rate of exercise, and adaptive thermogenesis. This means that a change in energy intake influences energy expenditure in a dynamic way. Mechanisms associated with reduction of total energy expenditure following weight loss are likely to be related to decreased body mass and enhanced metabolic efficiency. Reducing calorie intake results in a decrease in body weight, initially with a marked reduction in fat free mass and a decrease in REE, and this change is maintained for several years in a reduced state. Metabolic adaptation, which is not explained by changes in body composition, lasts for more than several years. These are powerful physiological adaptations that induce weight regain. To avoid a typically observed weight-loss and regain trajectory, realistic weight loss goals should be established and maintained for more than 1 year. Using a mathematical model can help clinicians formulate advice about diet control. It is important to emphasize steady efforts for several years to maintain reduced weight over efforts to lose weight. Because obesity is difficult to reverse, clinicians must prioritize obesity prevention. Obesity prevention strategies should have high feasibility, broad population reach, and relatively low cost, especially for young children who have the smallest energy gaps to change.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.607-612
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• 2002

This paper presents the first domestic model product of hybrid Insulation low-loss type pole transformer, with increased overload ability, increased life, reduced loss, focusing improved short-circuit characteristics. The capacity of this transformer is 100 KVZ, rates first voltage 13200 V and secondary voltage 230/115 type. The volume of model transformer that was produced in high temperature using hybrid insulation can be reduced to 10-20% in comparison with that of present transformer with the same capacity. In this paper, we did short-circuit test and tested general characteristics of model transformer. In addition, we suggested design application new concept and methods thorough this experiment.