• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11a
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• pp.205-214
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• 1999

In order to investigate the influencing factors of flotation fractionation. flotations were performed at varied conditions. The selectivity of fines fractionation is mainly affected by long fibers flocculating degree and if it were not for sufficient flocculation of long fibers, increase of long fibers loss could not be avoided. The amount of flotation reject totally depends on the stability of forth floated on the stock surface. only the small size fines stabilize the froth as they hinder the drainage of liquid lamella in flotation-froth. Two important factors of flotation conditions are improving the flocculation of long fibers and increasing the amount of flotation reject. Changing a flotation flux or an air-mixing ratio with aims of increasing the flocculation of fibers and reject ratios is in conflict. In order to satisfy the both conditions for reducing long fiber loss and for increasing flotation reject a new fractionation promoter is urgently required.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.45-46
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• 2016

As coal fly ash emissions have increased due to additional constructions of domestic heat power plants, the amount of embedded reject ash (Rj henceforth) is increasing as well. Most Rj is embedded, so if it is used as an alternative admixture instead of cement, embedded quantities will decrease, leading to economic and environmentally positive effects. Therefore this study conducted an experiment to contemplate the usability of Rj ground in the Los Angeles abraser, and what effects ground Rj has on the engineering properties of high compressive strength mortar. The result was that as the number of grinding turns increased, liquidity, air quantity and intensity were improved, proving Rj a possible alternative admixture to cement.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.96-97
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• 2016

As coal fly ash emissions have increased due to additional constructions of domestic heat power plants, the amount of embedded reject ash (Rj henceforth) is increasing as well. Most Rj is embedded, so if it is used as an alternative admixture instead of cement, embedded quantities will decrease, leading to economic and environmentally positive effects. Therefore this study conducted an experiment to contemplate the usability of Rj ground in the Los Angeles abraser, and what effects ground Rj has on the engineering properties of poor-mix mortar. The result was that as the number of grinding turns increased, liquidity, air quantity and intensity were improved, proving Rj a possible alternative admixture to cement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12B
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• pp.1733-1740
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• 2001

A monolithic 5 GHz image reject mixer using a 0.5-m GaAs MESFET technology is designed and simulated. The Mixer exhibits a 13.56 dB down-conversion gain, a SSB (Single SideBand) noise figure of 11.91 dB, an input IP3 (third order intercept point) of -3.73 dBm and a PldB (1-dB compression point) of -11.0 dBm. The critical issue in the image reject mixer is the phase accuracy and magnitude balance of the 90 phase shifting network. The proposed image reject mixer realizes a 90 phase shifter on chip. This phase shifting network does not need any phase adjusting to achieve the phase error specification of 3 over a frequency range from 800 MHz to 1GHz. The simulated overall image rejection ratio is better than 50 dB.

• Communications for Statistical Applications and Methods
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• v.16 no.6
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• pp.997-1004
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• 2009

A standard approach is to classify all of future observations. In some cases, however, it would be desirable to defer a decision in particular for observations which are hard to classify. That is, it would be better to take more advanced tests rather than to make a decision right away. This motivates a classifier with a reject option that reports a warning for those observations that are hard to classify. In this paper, we present the method which gives efficient computation with a reject option. Some numerical results show strong potential of the propose method.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.4
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• pp.201-206
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• 2013

The coal bottom ash and reject ash discharged from a coal-fired power plant are difficult to recycle so most of them are mainly landfill-disposed. In this study, the artificial aggregate were produced using reject ash, bottom ash and dredged soil emitted from the coal-fired power plant in Korea and the effect of experimental factors on the bloating behavior and the properties of the aggregates were analyzed. In particular, a lot of unburned carbon in the reject ash was removed by calcination and the activated carbon was added to batch powders then the dependence of those process upon bloating properties of artificial aggregate were investigated. For this purpose, the specific gravity and water absorption values of artificial aggregates were investigated in conjunction with microstructural observations. This study could contribute to increase the recycling rate of the reject ash.

• Journal of Environmental Science International
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• v.19 no.3
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• pp.323-329
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• 2010

To acquire preliminary data for the control of total nitrogen (TN) in S sewage treatment plant, which processes merging food waste and sewage, the effect of reject water on the total nitrogen in the effluent was examined in this study. Water quality data for the plant during the winter period were applied to calculate the mass balance. It was calculated that at least more than 231 kg/d TN should be removed to control the TN concentration in the effluent. Assuming 18 ppm as the goal TN concentration in the effluent, about 941 kg/d TN should be removed from this plant. Approximately 10% more TN should be removed than at present to achieve this result. It was observed that dewatering the filtrate had a considerably greater effect on the total nitrogen in the effluent than the reject waters. The dewatered filtrate contained 1,399kg/d TN. The contribution of the dewatered filtrate to the TN concentration in the effluent was 0.183, which was 7 to 23 times greater than the other reject waters. In addition, the amount of total nitrogen from the reject water, with the exception of the dewatering filtrate, was lower than the amount of TN that should be removed from S sewage treatment plant. Therefore, it was concluded that one of the most effective methods for controlling the TN concentration in effluent was the removal of the TN contained in the dewatering filtrate.

• Journal of electromagnetic engineering and science
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• v.10 no.1
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• pp.25-27
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• 2010

This paper presents a gain and phase mismatch calibration technique for an image-reject RF receiver. The gain mismatch is calibrated by directly measuring the output signal amplitudes of two signal paths. The phase mismatch is calibrated by measuring the output amplitude of the final IF output at the image band. The calibration of the gain and phase mismatch is performed at power-up, and the normal operation of the RF receiver does not interfere with the mismatch calibration circuit. To verify the proposed technique, a 2.4-GHz Weaver image-reject receiver with the gain and phase mismatch calibration circuit is implemented in a 0.18-${\mu}m$ CMOS technology. The overall receiver achieves a voltage gain of 45 dB and a noise figure of 4.8 dB. The image rejection ratio(IRR) is improved from 31 dB to 59.76 dB even with 1 dB and $5^{\circ}$ mismatch in gain and phase, respectively.

• Korean Journal of Human Ecology
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• v.22 no.4
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• pp.525-537
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• 2013

This study investigated the relations among a child's emotionality, mother's depression and parenting behaviors in predicting a child's happiness. Participants were 384 children(175 boys, 209 girls) and their mothers. The teachers completed the rating scale to measure a child's happiness. A child's emotionality, mother's depression and parenting behaviors were assessed by a mother-reported questionnaire. The collected data was analyzed using descriptive statistics, correlations, and hierarchical multiple regressions. Results showed that child's emotionality was negatively related to their happiness. Mother's depression had a negative relation to child's happiness. Mother's warmth-encouragement, overprotection-permission, and reject-nonintervention was significantly related to a child's happiness. Hierarchical regression analysis indicated that the interaction of child's emotionality and mother's reject-nonintervention predicted child's happiness. Child's emotionality, whose mother demonstrated a higher level of reject-nonintervention, was associated significantly with happiness. In addition, the association between mother's depression and child's happiness was mediated by mother's warmth-encouragement and reject-nonintervention. Results suggest the importance of mother's role in the context of intervention planning for child's happiness.

• Journal of the Korean Ceramic Society
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• v.53 no.2
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• pp.234-240
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• 2016

Energetically-modified material using reject fly ash (RFA), generated from thermal power plants, was manufactured to investigate the effect of the material on the physical and chemical characteristics of cement mortar. In order to modify reject fly ash, a vibration mill was used. Particle size, grain shape, and crystal structure of the ash were analyzed. Then, the compressive strength of the mortar using energetically-modified reject fly ash (ERFA) was measured. Microstructure and X-ray diffraction (XRD) patterns were also used in the analysis. As the replacement rate of ERFA increased, the value of the compressive strength tended to decrease. However, it was found that the compressive strength values of 7 and 28 days-cured specimens were higher than those of conventional ordinary Portland cement (OPC) mortar with 10 % replacement rate condition.