• Bulletin of the Korean Chemical Society
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• 제29권3호
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• pp.541-545
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• 2008

Stable molecular isomers were calculated for the azobenzene crown ether p-tert-butylcalix[4]arene (1) in the host and their alkali-metal-ion complexes. The structures of two distinct isomers (cis and trans) have been optimized using DFT B3LYP/6-31G(d,p) method. Trans isomer of 1 is found to be 11.69 kcal/mol more stable than cis analogue. For two different kinds of complexation mode, the alkali-metal-cation in the crown-ether moiety (exo) has much better complexation efficiency than in the benzene-rings (endo) pocket for both isomers of 1. Sodium ion has much better complexation efficiency than potassium ion in all kinds of complexation mode with host 1. The Na+ complexation efficiency of the trans-complex (1) in the exo-binding mode is 8.24 kcal/mol better than cis-exo analogue.

• 한국임상수의학회지
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• 제18권3호
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• pp.297-303
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• 2001

A female pug was presented with severe anemia, dyspnea and hemoglobinuria. By B- and M-mode echocardiography, the large number of heartworm were founded in the right ventricle, right atrium and pulmonary artery. The heartworm mass was moved from the right ventricle to the right atrium with the motion of the tricuspid value. Paradoxic septum motion were visible in M-mode of left ventrcular outflow tract and chordae tendineae level short-axis view. Flattened interventricular septum was find in B-mode of papillary muscle level short-axis view. In autopsy, 81 adult heartworms and 7 filarial debris were found. Most of adult heartworm were found in the right ventricle and pulmonary artery. 3 of them were found in the venaca and right atrium, respectively.

• JSTS:Journal of Semiconductor Technology and Science
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• 제11권4호
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• pp.256-261
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• 2011

We demonstrate 3-Gb/s wireless link using a 60-GHz receiver front-end fabricated in $0.25-{\mu}m$ SiGe:C bipolar complementary metal oxide semiconductor (BiCMOS) and a mixed-mode quadrature phase-shift keying (QPSK) demodulator fabricated in 60-nm CMOS. The 60-GHz receiver consists of a low-noise amplifier and a down-conversion mixer. It has the peak conversion gain of 16 dB at 62 GHz and the 3-dB intermediate-frequency bandwidth of 6 GHz. The demodulator using 1-bit sampling scheme can demodulate up to 4.8-Gb/s QPSK signals. We achieve successful transmission of 3-Gb/s data in 60 GHz through 2-m wireless link.

• Journal of electromagnetic engineering and science
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• 제17권1호
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• pp.9-13
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• 2017

In this work, a broadband composite right/left-handed (CRLH) half-mode substrate integrated waveguide (HMSIW) quadrature Wilkinson power divider is proposed. The proposed CRLH-HMSIW quadrature power divider includes a microstrip Wilkinson power divider on the transition structure between the microstrip and HMSIW, and two thru transmission lines for the HMSIW and the CRLH-HMSIW. The measured amplitude, phase difference and isolation between the two output ports of the proposed structure have 1 dB, ${\pm}5^{\circ}$ and less than -15 dB in a wide frequency range of 4.1-6.68 GHz with 47.9% bandwidth, respectively.

• ETRI Journal
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• 제33권5호
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• pp.810-813
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• 2011

We report the use of a widely tunable detuned dual-mode laser diode (DML) as a compact and portable continuous-wave THz emitter. The wavelength difference between the two lasing modes of this DML can be tuned from 2.4 nm to 9.3 nm by using integrated microheaters. The power difference between these modes is less than 1 dB, and the side-mode suppression ratio is greater than 30 dB over the entire tuning range.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.529-534
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• 2003

Comprehensive study on the system, including blower and ducts, of HVAC device of a vehicle has been carried out for improvements of noise characteristics. The parameters of design improvements are concerned with geometric informations such as the shape of ducts and presence of a windshield window. Test results show that noise level increasing the following order: HV (HD) < V (D) < BH ${\sim}$ BHV (BHD) < B (B, H, V, D denote for blower, heater unit, vent duct, defrost duct, respectively). The effects of windshield glass on the noise level in the case of defrost mode are pronounced and the effects of the geometry of ducts on the overall HVAC noise prove to be not small.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권9호
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• pp.431-436
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• 2005

This paper studies a novel boost DC-DC converter operated high efficiency for discontinuous current mode (DCM) control. The converter worked in DCM eliminates the complicated circuit control requirement, reduces a number of components, and reduces the used reactive components size. In the general DCM converter, the switching devices are turned-on the zero current switching (ZCS), and the switching devices must be switched-off at a maximum reactor current. To achieve the zero voltage switching (ZVS) at the switching turn-off, the proposed converter is constructed by using a new loss-less snubber circuit. Soft-switched operation of the proposed boost converter is verified by digital simulation and experimental results. A new boost converter achieves the soft-switching for all switching devices without increasing their voltage and current stresses. The result is that the switching loss is very low and the efficiency of boost DC-DC converter is high.

• Journal of electromagnetic engineering and science
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• 제12권2호
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• pp.171-175
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• 2012

In this work, a new microstrip-to-substrate integrated waveguide (SIW) transition using the parallel half-mode substrate integrated waveguide (HMSIW) is proposed. The proposed transition consists of three sections : a microstrip, parallel HMSIWs, and an SIW. By inserting the parallel HMSIWs section between the microstrip section and the SIW section, the proposed transition can improve the return loss characteristics of the near cut-off frequency because the HMSIWs section has a lower cut-off frequency than the SIW section (8.6 GHz). The lower cut-off frequency is achieved through gradual electromagnetic field mode changes for a low reflection. The measured return loss is less than 20 dB in the of 9.1~16.28 GHz freqeuncy range for the back-to-back transition. The measured insertion loss is within 1.6 dB for the back-to-back transition. The proposed transition is expected to play an important role in wideband SIW circuits fed by a microstrip.

• Clinical Pain
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• 제20권1호
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• pp.7-14
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• 2021

Musculoskeletal ultrasound has evolved as the essential tool to diagnose and guide intervention procedures in people with neuromusculoskeletal conditions. Image optimization and understanding device operations are core components for ultrasound guided intervention procedure training. All ultrasound machines share the common operative features and there are various buttons for the features in the device control panel. Ultrasound "knobology" refers to the thorough understanding of imaging optimization. This review addressed basic information for the transducers, depth setting, gain and focus control, different modes focusing on brightness and doppler modes.

• 한국자동차공학회논문집
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• 제10권4호
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• pp.149-157
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• 2002

This paper is to investigate collapse mechanisms of CFRP(Carbon Fiber Reinforced Plastics)composite tubes and to evaluate collapse characteristics on the change of interlaiminar number and ply orientation angle of outer under static and impact axial compression loads. When a CFRP composite tube is crushed, static/impact energy is consumed by friction between the loading plate and the splayed fronds of the tube, by fracture of the fibers, matrix and their interface. These are associated with the energy absorption capability. In general, CFRP tube with 6 interlaminar number(C-type), absorbed more energy than other tubes(A, B, D-types). The maximum collapse load seemed to increase as the interlaminar number of such tubes increases. The collapse mode depended upon orientation angle of outer of CFRP tubes and loading status(static/impact). Typical collapse modes of CFRP tubes are wedge collapse mode, splaying collapse mode and fragmentation collapse mode. The wedge collapse mode was shown in case of CFRP tubes with 0° orientation angle of outer under static and impact loadings. The splaying collapse mode was shown in only case of CFRP tubes with 90°orientation angle of outer under static loadings, however in Impact tests those were collapsed in fragmentation mode .