• Korean Journal of Computational Design and Engineering
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• v.5 no.3
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• pp.276-284
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• 2000

Usual practice of the transformation of a B-spline curve into a set of piecewise polynomial curves in a power form is done by either a knot refinement followed by basis conversions or applying a Taylor expansion on the B-spline curve for each knot span. Presented in this paper is a new algorithm, called a direct expansion algorithm, for the problem. The algorithm first locates the coefficients of all the linear terms that make up the basis functions in a knot span, and then the algorithm directly obtains the power form representation of basis functions by expanding the summation of products of appropriate linear terms. Then, a polynomial segment of a knot span can be easily obtained by the summation of products of the basis functions within the knot span with corresponding control points. Repeating this operation for each knot span, all of the polynomials of the B-spline curve can be transformed into a power form. The algorithm has been applied to both static and dynamic curves. It turns out that the proposed algorithm outperforms the existing algorithms for the conversion for both types of curves. Especially, the proposed algorithm shows significantly fast performance for the dynamic curves.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2190-2194
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• 2024

The study investigates the dose-dependent direct X-ray sensing characteristics of Brucinium benzilate (BB) and N-acetylglycine (NAG) organic crystals. BB and NAG were prepared as a slurry and deposited as a thick film on a patterned metal electrode. The X-ray induced photocurrent response was examined for various exposure doses using an intraoral pulsed 70 keV X-ray machine connected to a source meter. Subsequently, the morphological properties and thickness of the thick films were analyzed using scanning electron microscopy (SEM). At a photon energy of 70 keV, the attenuation coefficient values for NAG and BB crystals were determined to be approximately 0.181 and 0.178 cm²/g, respectively. The X-ray stopping power of the crystals was measured using a suniray-2 X-ray imaging system. To evaluate the responsiveness of the sensors, the photocurrent sensitivity and noise equivalent dose rate (NED) were calculated for both thick films. The findings demonstrated a noteworthy capability of sensing low doses (mGy), thereby suggesting the potential application of these organic materials in X-ray sensor development.

• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.5
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• pp.32-37
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• 1982

This paper shows a design method of English/Hanguel/Chinese display controller using address conversion thchnique and DMA in the raster scanning graphic CRT display by giving a design example (64 characters$\times$16 lines display controller).

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1201-1203
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• 2011

A one-pot conversion of tertiary thioamides to S-2-oxo thioesters is reported. Hence, tertiary thioamides were reacted with ${\alpha}$-halo ketones or acids under solvent-free conditions to produce the corresponding oxo-thioesters in good to excellent yields.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1446-1448
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• 1997

TEC(Thermoelectric conversion) is direct conversion method between thermal energy and electric energy. We studied on the mechanical, electrical and thermal properties of thermoelectric module and made experimental thermoelectric generator with BiTe material.

• Journal of Electrical Engineering and Technology
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• v.11 no.5
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• pp.1526-1526
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• 2016

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.12
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• pp.77-84
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• 2007

In this parer, a wideband low-noise amplifier (LNA) has been realized in a 0.18mm CMOS technology for the applications of subsampling direct-conversion RF receivers. By exploiting the inverter-type transimpedance input stage with a 3rd-order Chebyshev matching network, the wideband LNA demonstrates the measured results of the -3dB bandwidth of 5.35GHz, the power gain (S21) of $12\sim18dB$, the noise figure (NF) of $6.9\sim10.8dB$, and the broadband input/output impedance matching of less than -10dB/-24dB within the bandwidth, respectively. The chip dissipates 32.4mW from a single 1.8V supply, and occupies the area of $0.56\times1.0mm^2$.

• Clean Technology
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• v.22 no.3
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• pp.196-202
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• 2016

In this study, ceria- based catalysts were prepared for dimethyl carbonate (DMC) synthesis and reaction conditions were evaluated for finding the optimal reaction route. In order to find optimal catalysts for DMC synthesis, calcination temperature and Cu(II) impregnation amount were evaluated. The oxidative carbonylation using methanol, carbon monoxide and oxygen and the direct synthesis using methanol and carbon dioxide were introduced for producing DMC. Following the law of Le Chatelier, the dehydration reaction was applied for enhancing the reactivity (methanol conversion) as removing water during the reaction. 2-cyanopyridine, as a chemical dehydration agent, was used. In the case of the oxidative carbonylation, methanol conversion rate increased from 15.1% to 38.7% and the DMC selectivity increased from 0% to 98.8%. In the case of the direct synthesis, methanol conversion rate increased from 1.0% to 77.8% and the DMC selectivity increased from 41.2% to 100.0%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.6 s.97
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• pp.603-614
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• 2005

In this paper, digital ultra-narrowband Walky-Talky using direct conversion method for CQPSK modulation scheme is implemented with satisfying the requirements of APCO P25. RF transceiver design and implementation scheme that minimize the influence of DC-offset and AC-coupling at ultra-narrowband is proposed. This scheme also minimizes the influence of nonlinear characteristic at power amplifier fir CQPSK modulation method. Test results of full system including DSP module and direct conversion RF transceiver show that FCC emission mask at 36.8 dBm PEP meets the standard requirements. The characteristic of receiver AGC by PWM control signal is linear at 40 dB dynamic range and voice communication at input power level of -116 dBm is successful. Also it is verified that the performance of BER versus frequency offset and versus SNR meets the standard requirements.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2194-2200
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• 2010

In this paper, the power detectors using metamaterials were designed and fabricated for multi-band six-port direct conversion method. The RF short-stubs for power detector were designed by using metamaterials which provide multi-band characteristics. The power detectors with metamaterial RF short-stub were analyzed and fabricated by using lumped and distributed element. The measured results of metamaterial power detectors show the good agreement with the simulation results. The performance of lumped-metamaterial RF short-stub shows the insertion loss below 1 dB and the good frequency response characteristics. Also, the distributed-metamaterial RF short-stub shows the good frequency response characteristics and the insertion loss under that of lumped-metamaterial RF short-stub. The multi-band power detectors with metamaterial RF short-stub detect the input RF signal in the designed dual frequency bands very well.