• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.32-36
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• 2003

In this work, we have designed a fully integrated 2.4GHz LC-tuned voltage-controlled oscillator (VCO) with multiple tuning inputs for a 0.25-$\mu\textrm{m}$ standard CMOS process. The design of voltage-controlled oscillator is based on an LC-resonator with a spiral inductor of octagonal type and pMOS-varactors. Only two metal layer have been used in the designed inductor. The frequency tuning is achieved by using parallel pMOS transistors as varactors and back-gate tuned pMOS transistors in an active region. Coarse tuning is achieved by using 3-bit pMOS-varactors and fine tuning is performed by using back-gate tuned pMOS transistors in the active region. When 3-bit digital and analog inputs are applied to the designed circuits, voltage-controlled oscillator shows the tuning feature of frequency range between 2.3 GHz and 2.64 GHz. At the power supply voltage of 2.5 V, phase noise is -128dBc/Hz at 3MHz offset from the carrier. Total power dissipation is 7.5 mW.

• Journal of information and communication convergence engineering
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• v.4 no.1
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• pp.18-22
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• 2006

A small-sized gas identification system has been fabricated and characterized using an integrated gas sensor array and artificial neural-network. The sensor array consists of four thick-film oxide semiconductor gas sensors whose sensing layers are $In_{2}O_{3}-Sb_{2}O_{5}-Pd-doped\;SnO_2$ + Pd-coated layer, $La_{2}O_{5}-PdCl_{2}-doped\;SnO_2,\;WO_{3}-doped\;SnO_{2}$ + Pt-coated layer and $ThO_{2}-V_{2}O_{5}-PdCl_{2}\;doped\;SnO_{2}$. The small-sized gas identification instrument is composed of a GMS 81504 containing an internal ROM (4k bytes), a RAM (128 bytes) and four-channel AD converter as MPU, LEDs for displaying alarm conditions for three gases (liquefied petroleum gas: LPG, liquefied natural gas: LNG and carbon monoxide: CO) and interface circuits for them. The instrument has been used to identify alarm conditions for three gases among the real circumstances and the identification has been successfully demonstrated.

• Transactions on Electrical and Electronic Materials
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• v.7 no.3
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• pp.123-128
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• 2006

The microstructure and electrical properties of the varistors, which are composed of $ZnO-Pr_6O_{11}-CoO-Cr_2O_3-La_2O_3-based$ ceramics, were investigated for different $La_2O_3$ contents. The increase of $La_2O_3$ content led to more densified ceramics, whereas abruptly decreased the nonlinear properties by incorporating beyond 1.0 mol%. The highest nonlinearity was obtained from 0.5 mol% $La_2O_3$, with the nonlinear coefficient of 81.6 and the leakage current of $0.2{\mu}A$. The increase of sintering time and temperature greatly decreased the nonlinear properties. As the $La_2O_3$ content increased, the donor density increased from $0.64\times10^{18}/cm^3\;to\;16.89\times10^{18}/cm^3$ and the barrier height greatly decreased with increasing $La_2O_3$ content, reaching a maximum (1.47 eV) in 0.5 mol% $La_2O_3$.

• Journal of Pharmaceutical Investigation
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• v.18 no.4
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• pp.209-215
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• 1988

The three-dimensional structures of piroxicam crystallized from two different solvents, toluene and toluene/hexane mixture respectively, are proved identical: $C_{15}H_{13}N_3O_4S,\;M\;=\;331.35$, monoclinic, a = 7.128(1), b = 15.146(2), c = 13.956(2) ${\AA},\;{\beta}=\;97.33(1)^{\circ},\;V\;=\;1494.37{\AA}^{3},\;Dx\;=\;1.472\;g/cm^{3},\;Z\;=\;4,\;space\;group\;P2_{1}/c,\;Mo\;K{\alpha}(\lambda=\;0.71073\;{\AA})$, F(000) = 688, T = 295 K, R = 0.0611 for 1993 unique observed reflections. The thiazine ring exhibits a half chair conformation. An amide group is involved in an intramolecular hydrogen bond to the hydroxy group, O(17)-H(17)${\cdots}O(15){\AA}$. The molecule is planar within 2 ${\AA}$ with the interplanar angle $127.9(4)^{\circ}$ between pyridine and benzene rings. A molecular chain parallel to [011] is formed by two intermolecular hydrogen bonds N(16)-H(6)${\cdots}O(11)$ and C(6)-H(6)${\cdots}O(11)$, and the molecular chains are held together by van der Waals forces.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.128-131
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• 2003

The number of grain is determined based on Poisson distribution in respectively different active channel and it is converted to grain size which affects to the mobility and threshold voltage. the acquired data is applied to the SPICE for observing the variation of I-V characteristic with several channel lengths. we can confirm the effect on device.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.26 no.4
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• pp.122-128
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• 2018

A compound drone that combines a fixed wing and a rotary wing is an aircraft that can take off and landing vertically, and can increase flight time and fly faster with fixed wings. The compound drones are divided into many types depending on the method of adding the thrust vectoring or the lift fan and the position of the rotor. In this study, we designed and fabricated a composite drone with four V-TOL motors in a fixed-wing, and assigned missions to the aviation body, hence judged mission accuracy using the actual flight test. The design process and the mission evaluation process employed in this study can be utilized on the development of various unmanned aerial vehicle.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.3
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• pp.122-128
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• 2023

This paper proposes two kinds of single-balanced direct conversion quadrature receivers using selfoscillating LMVs in which the voltage-controlled oscillator (VCO) itself operates as a mixer while generating an oscillation. The two LMVs are complementary coupled and series coupled to generate the quadrature oscillating signals, respectively. Using a 65 nm CMOS technology, the proposed quadrature receivers are designed and simulated. Oscillating at around 2.4 GHz frequency, the complementary coupled quadrature receiver achieves the phase noise of -28 dBc/Hz at 1KHz offset and -109 dBc/Hz at 1 MHz offset frequency. The other series coupled receiver achieves the phase noise of -31 dBc/Hz at 1KHz offset and -109 dBc/Hz at 1 MHz offset frequency. The simulated voltage conversion gain of the two single-balanced receivers is 37 dB and 45 dB, respectively. The double-sideband noise figure of the two receivers is 5.3 dB at 1 MHz offset. The quadrature receivers consume about 440 μW dc power from a 1.0-V supply.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.128.3-129
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• 2003

A leaf blight disease caused by a species of Phytophthora has been observed on castor bean plants growing near dwelling houses in Manchon-dong, Daegu since 1993. The first isolate that we have kept was producing papillate, ovoid-obpyriform to obpyriform sporangia with on a simple sympodial sporangiophore from diseased tissue placed on water agar plates. The pure isolate, however, did not sporulate on agar media, and rarely even in water, but produced mycelial swellings and chlamydospores in water. Sporangia measured 26.1-77.4 ${\times}$ 23.2-44.0$\mu\textrm{m}$. Chlamydospores were either terminal or intercalary, and measured 24-29.4$\mu\textrm{m}$ in diameter. Sex organs were not formed in a single culture. In 2003, another pure isolate was isolated from castor bean plants with similar symptoms at the same place. The second isolate was distinct from the first one in that the second isolate was readily and abundantly sporulating on V8 juice agar plates. Sporangia of the second isolate were papillate, ovoid and caduceus with a pedicel. Sporangia measured 19.5-48.8 x 17.6-34.3$\mu\textrm{m}$ with 3.7$\mu\textrm{m}$ high papilla and 4.1$\mu\textrm{m}$ long pedicel. No sex organs were formed in a single isolate culture. Both isolates were pathogenic on castor bean plants. Results of the efforts to identify the two species of Phytophthora will be discussed.

• Advances in aircraft and spacecraft science
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• v.10 no.4
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• pp.317-334
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• 2023

This paper presents a basic methodology and a set of numerical tools for the preliminary design of solid-fueled ramjet missiles. An elementary code determines the baseline system configuration comprised of warhead, guidance-control, and propulsion masses and geometries from specific correlations found in the literature. Then, the system is refined with the help of external and internal ballistics codes. Equations of motion are solved for the flight's ascending, cruising, and descending stages and the internal ballistic set of equations designs the ramjet engine based on liquefying fuels. The combined tools sized the booster and the ramjet sustainer engines for a long-range missile, intended to transport 200 kg of payload for more than 300 km range flying near 14,000 m altitude at Mach 3.0. The refined system configuration had 600 mm in diameter and 8,500 mm in length with overall mass of 2,128 kg and 890 kg/m3 density. Ramjet engine propellant mass fraction was estimated as 74%. Increased missile range can be attained with paraffin-polyethylene blend burning at near constant regression rate through primary air mass flow rate control and lateral 2-D air intakes.

• Korean journal of applied entomology
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• v.42 no.3
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• pp.173-184
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• 2003

Beetles belonging to the families Scolytidae, Platypodidae, Bostrichidae, and Lyctidae intercepted from imported timbers at Busan port were investigated from March 1 to November 30 in 2000. In addition, hosts imported country were examined. A total of 52 species of within 23 genera was intercepted from nineteen species of timbers or logs from fifteen countries. In Scolytidae, 35 species of 16 genera in three subfamilies were identified 12 species in Xyleborus, 6 species in Ips, 3 species in Trypodendron, 2 species in Arixyleborus, and 12 species of all different genera including Alinphagous. Scolytidae were intercepted from 16 species of timbers in 13 genera imported from 11 countries. The highest beetles were intercepted from Malaysian lauan. In Platypodidae, 9 species of one genus (Platypus) were intercepted from 6 species of timbers in 4 genera imported from 6 countries including Australia. The highest numbers were intercepted from Malysian lauan. In Bostrychidae, 5 species of 4 genera in two subfamilies were intercepted from 6 species of timbers in 4 genera imported from four countries. In Lyctidae, Trogoxylon sp., Minthea sp., and Minthea rugicollis were intercepted from 3 species of timbers in 2 genera imported from 3 countries.