• The Journal of the Acoustical Society of Korea
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• v.20 no.3E
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• pp.31-37
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• 2001

Finite element model of a cMUT is constructed using the commercial code ANSYS to analyze the cross talk mechanism. Calculation results of the complex load impedance seen by single capacitor cells are presented, and then followed by a calculation of the plane wave real load impedance seen by a parallel combination of many cells that are used to make a transducer. Cross talk between 1-D array elements is found to be due to two main sources: coupling through a Stoneley wave propagating at the transducer-water interface and coupling through Lamb waves propagating in the substrate. To reduce the cross talk level, the effect of various structural variations of the substrate are investigated, which include a change of its thickness and etched trenches or polymer walls between array elements.

• Clean Technology
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• v.17 no.1
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• pp.13-18
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• 2011

Phosphine ligand-grafted mesoporous silica materials with large pores were prepared for the ligand-modified heterogeneous Pd nanocatalysts. New heterogeneous catalytic system was developed using palladium nanoparticles encapsulated in phosphine ligand-grafted mesoporous silica. The catalyst showed good catalytic activities for Suzuki cross-coupling using bromobenzene derivatives due to excellent phosphine ligand effects. Catalytic results showed nanoparticie catalysts can be recycled twice with decreased yields.

• Journal of Chest Surgery
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• v.17 no.2
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• pp.197-204
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• 1984

The criss-cross, a term first used by Anderson and Ando , is a rare cardiac malformation in which the systemic and pulmonary blood streams cross at the atrioventricular level, without mixing. We have surgically experienced four cases of crossed atrioventricular connection, three concordant and one discordant, at Seoul National University Hospital from July 1982 to March 1984. The atrial situs, the atrioventriculoarterial connection, the spatial position of the ventricles, and associated cardiac anomalies were analyzed. We have performed right Blalock-Taussig shunt for case 1, modified Fontan operation for case 2, patch closure of VSD for case 3, and septation of common ventricle with primary closure of ASD for case 4. The relatively good postoperative results in these patients were gratifying and suggest that cardiac anomalies associated with this rare malformation can be successfully repaired without further risk. To our knowledge, this is the first report of surgical experience for criss-cross heart in the Korean literature.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.4
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• pp.437-442
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• 2014

Due to electrical cross-coupling between modulation voltage and photodetector output in a closed-loop fiber optic gyro, deadzone inevitably occurs. In this paper, deadzone error by cross-coupling effect was analyzed and the overcoming method was suggested. Simulation and measurement results show the main reason for deadzone is mainly related to electrical cross-coupling, and it can be effectively reduced by square-wave dithering method.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.262-265
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• 2007

Preliminary results are reported on ship detection using coherence images computed from cross-correlating images of multi-look-processed dual-polarization data (HH and HV) of ENVISAT ASAR. The traditional techniques of ship detection by radars such as CFAR (Constant False Alarm Rate) rely on the amplitude data, and therefore the detection tends to become difficult when the amplitudes of ships images are at similar level as the mean amplitude of surrounding sea clutter. The proposed method utilizes the property that the multi-look images of ships are correlated with each other. Because the inter-look images of sea surface are covered by uncorrelated speckle, cross-correlation of multi-look images yields the different degrees of coherence between the images and water. The polarimetric information of ships, land and intertidal zone are first compared based on the cross-correlation between HH and HV. In the next step, we examine the technique when the dual-polarization data are split into two multi-look Images.

• Cross-Cultural Studies
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• v.36
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• pp.175-209
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• 2014

This paper reports on a qualitative examining the cross-cultural reasons for student engagement and resistance to critical literacy in a three week summer TESOL MA course that was part of a Korean/American university faculty exchange program. Of particular interest was the unique diversity of the class which consisted of 13 subjects from 9 different nations. Using student and instructor reflective journals, field notes on classroom observations, and the course terminal paper on student's philosophies of education as research corpora, results of the study revealed that students resisted instruction in critical literacy for ideological and epistemological reasons. Nonetheless, the data also showed that while all students resisted some theories in critical literacy, all students nonetheless engaged the course content in meaningful ways.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.6
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• pp.279-288
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• 2017

Heat generation rate in a telecommunication cabinet increases due to the continued usage of mobile devices. Insufficient removal of heat intensifies the cabinet temperature, resulting in the malfunction of electronic devices. In this study, we assessed both aluminum and plastic heat exchangers used for cooling of the telecommunication cabinet, and compared the results against theoretical predictions. The aluminum heat exchanger was composed of counter flow parallel channels of 4.5 mm pitch, and the plastic heat exchangers were composed of cross flow triangular channels of 2.0 mm pitch. Samples were made by installing two plastic heat exchangers in both series and parallel. Results showed that the heat transfer rate was highest for the series cross flow heat exchanger, and was least for the aluminum heat exchanger. The temperature efficiency of the series cross flow heat exchanger was 59% greater than that of the aluminum heat exchanger, and was 4.3% greater than that of the parallel cross flow heat exchanger. In contrast, the pressure drop of the parallel cross flow heat exchanger was significantly lower than other samples. The heat exchange efficiency was also the largest for the parallel cross flow heat exchanger. The theoretical analysis predicted the temperature efficiency to be within 3.3%, and the pressure drop within 6.1%.

• The korean journal of orthodontics
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• v.25 no.6 s.53
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• pp.655-664
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• 1995

Sixty male patients with polysomnographically documented OSA were included in this study. A pair of cephalograms were obtained in the upright and supine positions. In the supine position, the ANB angle, lower facial height and the cross-sectional area of soft palate increased and there was a decrease in the vertical airway length and oropharynx cross-sectional area. Positional changes did not affect the cross-sectional area of tongue, but the cross-sectional area of the oropharynx decreased in the supine position. The obese group had higher AI and RDI. Maxillary unit length, C3-H, the cross-sectional areas of tongue, soft palate and oropharynx were significantly greater in the group Obese than in non-obese group. No correlation was noted between the mandibular unit length and OSA severity, The group of small mandibular unit length showed shorter lower facial height and maxillary unit length, and smaller cross-sectional area of tongue than the long mandibular unit length group. Hyold bone positioned more inferiorly and cross-sectional area of nasopharynx decreased as the OSA severity increased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.19
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• pp.1-6
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• 1975

From the cross Tongil$^2//IR833/IR1317$ glutinouse rice lines wx 126 were bred. Some of these lines were earlier than standard variety and later than glutinous check variety. Some of them yielded as much as standard variety and showed better resostances to blast, stripe deseases and smaller brown plant hopper than standard variety. It was sosscussed that, theough the vreedong procedure, following points were proved, 1)back-cross program in roce breeding was effocoent, 2)semi-dwarf plant type of "Tongil" has high yielding poteneoality and 3) the variety "Tongil" was a good for recurrent parent for back-cross program. back-cross program.

• Journal of the Korean Applied Science and Technology
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• v.33 no.4
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• pp.813-823
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• 2016

The purpose of this study was to investigate the effects of ionized calcium treatment on total bacterial cross-contamination of chicken carcass surface in the slaughtering process. The growth of Escherichia coli was strongly inhibited in a medium prepared by using a 0.5% ionized calcium solution. The total bacterial cross-contamination of chicken carcass surface and the scalding water was significantly increased as the number of scalding was increased (p<0.05). The total bacterial cross-contamination of chicken carcass surface reached a plateau without a further increase as scalding was performed consecutively for 10 or more times. The total bacterial cross-contamination of the scalding water was significantly increased as the number of scalding was increased (p<0.05). The total bacterial cross-contamination of chicken carcass surface of the chickens raised on a floor type farm was significantly higher than that of the chickens raised in a battery cages (p<0.05). The total bacterial cross-contamination of chicken carcass surface of the chickens raised on a floor type farm was significantly lower in the 0.5% ionized calcium solution treatment group than in the control group (p<0.05).