• Journal of Magnetics
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• v.1 no.1
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• pp.24-30
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• 1996

The relationship between effective permeability and the remanence ratio of an Fe-based amorphous alloy (Metglas 2605S3A) is investigated over a wide frequency range, in an effort to understand magnetization behavior of the alloy. In the frequency range from 1 to 200 kHz, the permeability is maximum at the remanence ratio of 0.4-0.5 and, at frequencies over 500 kHz, the correlation with negative coefficients emerges indicating that the permeability decreases with the remanent ratio, except for the ribbon coated with an insulating layer of MgO which exhibits both high values of the effective permeability and remanence ratio. It is considered from the correlation results that the boundary at which the dominant magnetization mechanism changes from domain wall motion to spin rotation is near 500 kHz. The core loss is also investigated as a function of annealing time when the samples are annealed at a fixed temperature of $435^{\circ}C$. The core loss in most cases decreases with the annealing time, the degree of the loss may consist of the hysteresis loss and anomalous eddy current loss. The two loss components are considered to be of similar magnitudes at low frequencies while, at high frequencies, the dominant contribution to the total loss is the anomalous loss.

• Journal of Chest Surgery
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• v.29 no.9
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• pp.989-995
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• 1996

Excessive blood loss secondary to cardiopulmonary bypass(CPB) may be encountered after open heart surgery and platelet dysfunction appears to be especially responsible for this problem. To evaluate the effect of low-dose aprotinin during hypothermic CPB on platelet aggregation, anticoagulation and clinical hemostasis,.40 patients undergoing valve replacement using hypothermic CPB procedures were randomized to give either a low dose aprotinin(2$\times$ 106 KIU in the CPB priming sol- ution, n=20) or a placebo(n=20). During postoperative 24 hours, blood and hemoglobin loss were lower in the aprotinin group (225.5 $\pm$ 121.9ml, and 11.3$\pm$2.4g) than the control group(572.2$\pm$)35.5ml and 26.3$\pm$9.8g)(P<0.01). The total blood and hemoglobin loss were lower in the aprotinin group (622.0$\pm$ 186m1 and 14.7$\pm$6.8g) than the con- trol group (102.1 $\pm$483.5ml and 39.7$\pm$ 16.4g) (P<0.01). The amonut of packed red cell needed decreased in the aprotinin group: 197.7$\pm$56.3ml vers s 651.2: 147.5ml (P<0.01). Hemoglobin concentration, platelet counts and fibrinogen checked at fixed times perioperatively did not differ between the two groups. Platelet aggregation was induced by ADP, collagen, epinephrine and ristocetin before and after CPB. Maximum platelet aggregation was significantly reduced after CPB in control group (ranging from -31 % to -58% relative to prebypass values). Significant prolongation of activated clotting time(ACT) after 5 minute and 30 minute of hypothermic CPB were observed: 955.9 $\pm$35.1 and 967.5$\pm$32.7sec versus 743.8 $\pm$ 52.1 and 731.2: 54.6sec (P<0.01). There was no complication associated with aprotinin infusion. These results demonstrate that low-dose aprotinin significantly reduces blood loss and blood requirment and provides improved postoperative hemostasis which might be related to protection of platelet aggregation capacity.

• Journal of Sericultural and Entomological Science
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• v.35 no.2
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• pp.114-119
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• 1993

The weight loss for the mixture(raw-silk/PET) was tested to investigate the effects of weight loss accelerator on the degumming and weight loss. The degumming loss of raw-silk was decreased while the weight loss polyester(PET) was increased depending on the increase of accelerator concentration. The difference of the weight loss was not significant in raw-silk but the weight loss of PET was increased with the increase of the alkali concentration. The proper degumming of raw-silk was obtained and simultaneously the weight loss of PET was high for the raw-silk/PET "A" and "B" type. The proper degumming of raw-silk was obtained but the weight loss of PET was low for the raw-silk/PET "D" and "E" type. It showed that the typical degumming curve in raw-silk part and the weight loss of PET was increased depending on the treatment time in the weight loss for the fabric composed of raw-silk and PET.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.218-223
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• 2008

In this paper, we implement several methods to improve an audio collaboration system over IP networks, and then evaluate the performance of the implemented methods. In general, speech and audio quality degrades depending on the characteristics of IP networks such as jitter and packet loss. In order to reduce this quality degradation, we propose a lower bit rate audio delivery scheme using the MPEG-2 AAC (Advanced Audio Coding) audio codec in a viewpoint that a packet loss rate could be reduced by a smaller packet size. In addition, iLBC (Internet Low-Bitrate Codec) and the G.711 packet loss concealment algorithm defined by IEFT and ITU-T, respectively, are applied to a audio collaboration system. RAT (Robust-Audio Tool)[7] is used as a baseline platform for the implementation of the proposed methods. It is shown from the implementation that the implemented MPEG-2 AAC audio codec with a bitrate of 256 kbit/s performs as similar as the uncompressed audio quality with a bitrate of 512 kbit/s, and that iLBC and the G.711 packet loss concealment algorithm can improve speech quality when a packet loss rate is 2~10%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.7
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• pp.606-611
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• 2009

AC loss is one of the important factors for commercialization of a high temperature superconducting (HTS) cable from an economic point of view. But AC loss characteristics of the HTS-cable are not elucidated completely because of its complex structure. As an earlier stage of analyzing the AC loss in the 22.9 kV/50 MVA, 100m HTS-cable system of Korea Electric Power Corporation (KEPCO) which is now in collaboration with us, a two-dimensional (2D) numerical model, which takes into account the nonlinear conductivity properties of a high temperature superconductor, has been developed. In order to examine our 2D model, we have prepared several single-layer cable samples whose AC losses are sufficiently reliable due to their simple structure. The AC losses of the samples were experimentally investigated and then compared with our 2D model. The results show that the numerically calculated AC losses are not in good agreement with the measured ones for the cylindrical cable and deca-cable samples with low critical current density. However, the numerically calculated and measured AC losses are relatively in good agreement for the deca-cable and hex-cable samples with high critical current density, although the difference between these two loss data in the deca-cable sample tends to increase in the low current region.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.8
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• pp.153-165
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• 1995

The design procedure of a GaAs/AlGaAs semiconductor matrix optical switch is presented for a simplified tree architecture in the viewpoint of optical loss. A low loss, 0.537 dB/cm, pin type substrate is designed by considering the loss due to imputity doping at 1.3 $\mu$m wavelength. The operating voltage and the device length of a reversed ${\Delta}{\beta}$ electro-optic directional coupler(EODC) swith which is a cross-point device of the 4${\times}$4 matrix optical switch and the bending loss of rib waveguide are caculated as functions of waveguide parameters and bending parameters. There is an optimum bending radius for some waveguide parameters. It is recommened that higher optical confinement conditions such as wide waveguide width and higher rib-height should be chosen for structural parameters of a low loss and a process insensitive 4${\times}$4 matris optical switch. A 4${\times}$4 optical matrix switch which has a 3 dB loss and a 12 volt operating voltage is designed.

• Journal of the Korean Society of Food Culture
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• v.18 no.2
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• pp.172-180
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• 2003

This study was performed to document the weight loss diet practice and dietary habit related to weight control in child-bearing Korean women. The subjects were 1,434 women aged 17-39 years. The subjects were classified into 3 groups based on BMI: low weight(LW) BMI < 18.5; normal weight(NW), 18.5 BMI 22.9; and overweight(OW), 23.0 BMI. Anthropometric, general characteristics, weight control practice, and the quality of diet were assessed by a questionnaire. LW group had higher rate of smoking and drinking. They also complained more subjective symptom of anemia and used less nutritional supplementation. Weight loss diet had been practiced by about 40% of subjects and the percent was increased with increasing BMI. The reason of weight loss diet were significantly different by BMI groups(p<0.05); LW to keep body in shape, OW for health. Low BMI group had experienced more side effects after weight loss diet(p<0.05). LW group usually used inappropriate method to control weight such as skipping meals and some of OW group reported using drug to lose weight. All subjects have been skipped their meals of 3.9 times per week, especially 4.3 times in LW group. By mini dietary assessment, most of the subjects did not have regular meals. LW group tended to eat what they like and OW group preferred fried food. This study showed that child-bearing aged women make a ceaseless effort apart from their weight, and LW group have a matter of grave concern because of their dietary habit and weight control practice. Additional research should be necessary to assess the relation of health and weight loss diet in young women.

• Food Science of Animal Resources
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• v.22 no.2
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• pp.172-178
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• 2002

Vitamins are bio-active materials and essential elements in our body but some of them are very low in milt Various vitamin-fortified milks are developed by the help of milk processing technology. However, heat treatments can affect vitamins contents in milk. Total loss of vitamins during the UBT(ultra high temperature) treatment was investigated. UHT treatment caused 60∼70% loss for vitamin C, and 30∼40% loss for vit. D3 and vit. E which are well-known as heat stable materials. On the contrary, degradation of water-soluble vitamins is relatively very low in the capsule-coated state. The capsule could reduce the loss of vitamins by protecting vitamins from the degradation factors such as heat, oxygen, lights etc. The fortification method using capsule can be thought as a new way to reduce the loss of vitamins during milk processing. Further study about heat treatment time and temperature, and capsule coating and materials will be required to minimize the loss of vitamins in milt.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.9
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• pp.63-69
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• 2021

This study aims to determine the flow characteristics of a one-inch small ball valve and glove valve used in industrial plants. The flow was changed through an experimental equipment, and the internal flow characteristics of the valves were compared. Considering the pressure drop, the decrease in the slope of the ball valve based on the degree of the valve opening was relatively greater than that of the glove valve; further, the slope of the glove valve was gentle while the pressure drop was high. The flow velocity of the ball valve remains consistent after the valve was opened by 70%, whereas the flow velocity of the glove valve constantly increased. The valve loss factor of the ball valve was relatively low compared with that of the glove valve. When the valve was opened by 20%, which is the beginning stage of the valve opening, the valve loss factor of the ball valve was high and gradually became low. This is a structural problem of the ball valve, and the loss factor is significant because the flow path installed at the ball valve has a considerably small area. However, the overall loss factor of glove valve is high because it has a complicated structure of flow path.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.1
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• pp.70-78
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• 1998

The present study has tested semi-empirical loss models for a reliable performance prediction of mixed-flow pumps with four different specific speeds. In order to improve the predictive capabilities, this paper recommends a new internal loss model and a modified parasitic loss model. The prediction method presented here is also compared with that based on two-dimensional cascade theory. Predicted performance curves by the proposed set of loss models agree fairly well with experimental data for a variety of mixed-flow pumps in the normal operating range, but further studies considering 'droop-like' head performance characteristic due to flow reversal in mixed-flow impellers at low flow range near shut-off head are needed.