• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.6
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• pp.63-69
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• 2008

Reconfigurable RF one-chip solutions have been researched with the objective of designing for smaller-sized and more economical RF transceiver and it can be applied to a vehicular wireless terminal. The proposed voltage-controlled oscillator satisfies the targeted frequency range ($4.2{\sim}5.4\;GHz$) and the frequency planning which correspond to the standards such as CDMA(IS-95), PCS, GSM850, EGSM, WCDMA, WLAN, Bluetooth, WiBro, S-DMB, DSRC, GPS, and DVB-H/DMB-H/L(L Band). In order to improve phase noise performance, PMOS is adopted in the cross-coupled pair, the tail current source and MOS varactor in this VCO and differential-typed switching is proposed in capacitor array. Based on the measurement results, a total power dissipation is $5.3{\sim}6.0\;mW$ at 1.8 V power supply voltage. The oscillator is tuned from 4.05 to 5.62 GHz; The tuning range is 33%. The phase noise is -117.16 dBc/Hz at 1 MHz offset frequency and the FOM (Figure Of Merit) is $-180.84{\sim}-180.5$.

• Membrane and Water Treatment
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• v.8 no.6
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• pp.575-590
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• 2017

PolyHIPEs membrane prepared with styrene (St), divinylbenzene (DVB), and ethylhexyl acrylate (EHA) can yield a unique pore structure provided by large voids highly interconnected by many small window throats. With the advantageous pore structure, PolyHIPE presents a potential as a support for carrier facilitated transport membrane. Tricaprylmethylammonium chloride (Aliquat 336) can be efficiently incorporated into the PolyHIPE membrane by a two-step solvent-nonsolvent method to obtain an Aliquat 336-immobilized PolyHIPE membrane with good stability. The study of Cr (VI) transport through Aliquat 336-immobilized PolyHIPE membrane indicates that the membrane has high initial flux and maxima stripping flux ($J_f^o=15.01({\mu}mol/m^2s)$, $J_s^{max}=6.15({\mu}mol/m^2s)$). The reusability study shows that the Aliquat 336-immobilized PolyHIPE membrane can maintain high Cr(VI) recovery efficiency even after 15 cycles of operations. The developed membrane was also used in the separation of Cr (VI) from other anions (i.e., $SO_4{^{2-}}$ and $NO_3{^-}$) and other cations (i.e., Ni (II), Mg (II) and Cu (II)) with good selectivity.

• Journal of the Korean Chemical Society
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• v.29 no.3
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• pp.283-286
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• 1985

The non porous and porous 4-vinylpyridine-divinylbenzene ion exchange resins were synthesized by the suspension polymerization method. The functional groups of these resins were identified by means of infrared adsorption spectroscopy. The pore volume and pore spectra of these synthesized resins were determined with a mercury porosimeter. The influence of diluent and percentage of divinylbenzene on the pore size and volume of the porous 4-vinylpyridine-divinylbenzene copolymer, P-4VPDVB, 50-100 mesh was discussed. The ion exchange capacity of non-porous and porous 4-vinylpyridine divinylbenzene resins was 5.0meq/g, respectively.

• Korean Journal of Materials Research
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• v.6 no.8
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• pp.761-767
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• 1996

The composite fiber adsorbents containing amidoxime group were prepared and separation properties of uranium ion from seawater were investigated. The amount of uranium adsorption was increased with an increase in adsorption time. When the mole ratio of monomer and comonomer, such as acrylonitrile (AN), tetraethyleneglycol dimethacrylate(TEGMA), and divinylbenzene (DVB), were 1 :0. 1 :0.003, this resin showed the maximum adsorption ability for uranium at a level of pH 8. The amount of uranium adsorption was also increased linearly to one hour with an increase in the content of adsorbent which was added in the composite fiber adsorbents(CFA). The maximum adsorption for uranium of CF A showed at $25^{\circ}C$. Hence, the adsorption ability of CF A for calcium and magnecium ions were increased gradually by the recycling of adsorption and disorption, the adsorption content of their on were 0.3, 0.9mmole/g-adsorbents, respectly. It also showed that the adsorption contents of Ca and \1g ions were much lower than them of uranium. The desorption of uranium on the CF A was carried out , bout 100% within 30min, and the desorption rate of various CF A were equalled.

• Journal of the Korean Chemical Society
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• v.31 no.5
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• pp.457-463
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• 1987

The total synthesis of insulin A chain (1-21) with properly protected sulfhdryl groups of three cysteins for the correct intra and inter disulfide bond formation has been accomplished on 2-bromopropionylated 2% DVB-styreneresin support employing manually operated rotary vessel. The sulfhydryl groups of cysteins were protected with acetamidomethyl, benzyl, and benzhydryl respectively. Glutamine and asparagine were attached to the peptide chain by active ester coupling, all other amino acids were coupled with DCC/HOBT. The synthesized peptide was purified by DEAE Sephadex A-25 and gel filtration Sephadex LH-20. The final product was found to be homogeneous by HPLC, electrophoresis, and amino acid analysis. The overall yield of the pure isolated peptide was 6%.

• ETRI Journal
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• v.41 no.3
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• pp.308-315
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• 2019

Due to its high spectrum efficiency, 64-amplitude phase-shift keying (64-APSK) is one of the primary technologies used in deep space communications and digital video broadcasting through satellite-second generation. However, 64-APSK suffers from considerable computational complexity because of the de-mapping method that it employs. In this study, a low-complexity de-mapping method for (4 + 12 + 20 + 28) 64-APSK is proposed in which we take full advantage of the symmetric characteristics of each symbol mapping. Moreover, we map the detected symbol to the first quadrant and then divide the region in this first quadrant into several partitions to simplify the formula. Theoretical analysis shows that the proposed method requires no operation of exponents and logarithms and involves only multiplication, addition, subtraction, and judgment. Simulation results validate that the time consumption is dramatically decreased with limited degradation of bit error rate performance.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.37-47
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• 2006

This work proposes a 10b 25MS/s $0.8mm^2$ 4.8mW 0.13um CMOS A/D Converter (ADC) for high-performance wireless communication systems such as DVB, DAB and DMB simultaneously requiring low voltage, low power, and small area. A two-stage pipeline architecture minimizes the overall chip area and power dissipation of the proposed ADC at the target resolution and sampling rate while switched-bias power reduction techniques reduce the power consumption of analog amplifiers. A low-power sample-and-hold amplifier maintains 10b resolution for input frequencies up to 60MHz based on a single-stage amplifier and nominal CMOS sampling switches using low threshold-voltage transistors. A signal insensitive 3-D fully symmetric layout reduces the capacitor and device mismatch of a multiplying D/A converter while low-noise reference currents and voltages are implemented on chip with optional off-chip voltage references. The employed down-sampling clock signal selects the sampling rate of 25MS/s or 10MS/s with a reduced power depending on applications. The prototype ADC in a 0.13um 1P8M CMOS technology demonstrates the measured DNL and INL within 0.42LSB and 0.91LSB and shows a maximum SNDR and SFDR of 56dB and 65dB at all sampling frequencies up to 2SMS/s, respectively. The ADC with an active die area if $0.8mm^2$ consumes 4.8mW at 25MS/s and 2.4mW at 10MS/s at a 1.2V supply.

• Applied Chemistry for Engineering
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• v.16 no.4
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• pp.485-490
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• 2005

Effects of gas injectino on the copper recovery form industrial waste water in a fluidized-bed electrolytic reactor were investigated. Effects of gas injection on the individual phase holdup and efficiency of copper recovery for given operating variables such as liquid and gas velocity (0.1~0.4 cm/s), current density ($2.0{\sim}3.5A/dm^2$) and amount of fluidized solid particles (1.0~4.0 wt%) were examined. The solid particle, whose diameter and swelling density were 0.5 mm and $1100kg/m^3$, respectively, was made of polystylene and divinyl benzene. It was found that the holdup of gas and solid phases increased, but that of the liquid phase decreased with increasing velocity of gas injected into the reactor. With increasing gas and/or liquid velocity and increasing amount of fluidized particles is not needed, the rate of copper recovery increased to a maximum value of and subsequently decreased. The recovery rate of copper increased almost linearly with increasing current density in accordance with Faraday's law.

• Journal of Broadcast Engineering
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• v.16 no.1
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• pp.23-32
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• 2011

Design and Implementation of Clipcast Service via Terrestrial DMB This paper outlines the system design and the implementation process of clipcast service that can send clips of video, mp3, text, images, etc. to terrestrial DMB terminals. To provide clipcast service in terrestrial DMB, a separate data channel needs to be allocated and this requires changes in the existing bandwidth allocation. Clipcast contents can be sent after midnight at around 3 to 4 AM, when terrestrial DMB viewship is low. If the video service bit rate is lowered to 352 Kbps and the TPEG service band is fully used, then 320 Kbps bit rate can be allocated to clipcast. To enable clipcast service, the terminals' DMB program must be executed, and this can be done through SMS and EPG. Clipcast service applies MOT protocol to transmit multimedia objects, and transmits twice in carousel format for stable transmission of files. Therefore, 72Mbyte data can be transmitted in one hour, which corresponds to about 20 minutes of full motion video service at 500Kbps data rate. When running the clip transmitted through terrestrial DMB data channel, information regarding the length of each clip is received through communication with the CMS(Content Management Server), then error-free files are displayed. The clips can be provided to the users as preview contents of the complete VOD contents. In order to use the complete content, the user needs to access the URL allocated for that specific content and download the content by completing a billing process. This paper suggests the design and implementation of terrestrial DMB system to provide clipcast service, which enables file download services as provided in MediaFLO, DVB-H, and the other mobile broadcasting systems. Unlike the other mobile broadcasting systems, the proposed system applies more reliable SMS method to activate the DMB terminals for highly stable clipcast service. This allows hybrid, i.e, both SMS and EPG activations of terminals for clipcast services.

• The Korean Journal of Food And Nutrition
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• v.17 no.4
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• pp.412-419
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• 2004

In odor to select optimum extraction methods of volatile compounds in beef extract powder(BEP) as basic data for the development of a new detection method of irradiated BEP, four extraction methods, such as solid phase microextraction with polar fiber(S-PD) and non-polar fiber(S-CD), purge and trap(P&T) and liquid liquid continuous extraction(LLCE) methods, were tested with gas chromatography/mass spectrometry method. A total of 106 volatile compounds including 22 hydrocarbons, 7 aldehydes, 6 ketones, 13 alcohols, 6 sulfur-containing compounds, 19 nitrogen-containing compounds, 6 aromatic compounds, 17 terpenes, 8 furans and 2 miscellaneous compounds were detected in BEP by four detection methods. The most compounds(62 compounds) were detected by S-PD method, followed by P&T(43), LLCE(38) and S-CD method(30). Among these methods, S-PD and P&T methods showed a complementary interrelationship to detect volatile compounds as S-PD method showed high detectabiltiy to all compound groups except hydrocarbons and ketones, which had high volatility and low molecular weight(less than RI 1200), but P&T method showed the contrary pattern to that of S-PD method. Moreover, the most of volatile compounds detected by S-CD and LLCE methods were also detectable by S-PD or/and P&T methods. Therefore, the simultaneous application of S-PD and P&T methods were selected as the optimum volatile extraction methods of BEP.