• Journal of Korean Society of Environmental Engineers
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• v.31 no.6
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• pp.419-427
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• 2009

To test applicability for continuous flow treatment of ultrasound technology, sonolysis of TCE aqueous solution using 584 kHz multi irradiation reactor was performed under batch and continuous flow conditions. Under batch condition (3 and 4 sides irradiation, 600 W), first order degradation rate constant of TCE was higher under 4 sides than 3 sides irradiation conditions, while the generation of $H_2O_2$ and chloride was similar under both irradiation conditions. Under continuous flow condition with 4 sides irradiation, removal efficiencies of TCE in steady-state were decreased from 83 to 48% with increasing flow rate from 67 to 300 mL/min at 600 W, and were increased from 14 to 75% with increasing acoustic power from 100 to 600 W at 100 mL/min. Removal efficiency of TCE in groundwater was decreased 10% compared to in distilled water at 100 mL/min and 600 W.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.6
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• pp.492-498
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• 1984

We have reported the seasonal and portional variation in the composition of uronic acid of alginic acid from Ecklonia cava in the previous study. In the present paper, uronic acid block structure of alginic acid from Ecklonia cave was investigated, and some related properties such as viscosity, the dependence on temperature and substitution of metallic ion were also discussed. The proportion M block was highest amnog three blocks in both of frond and stipe. The average values of M and G block ratios were $51.6|%\;and\;32.3\%$ in the frond, whereas $45.7\%\;and\;38.6\%$ in the stipe, respectively. The proportions of alternating blocks in the frond and stipe were similar, and the values were $16.1\%$ in the frond and $15.6\%$ in the stipe. The viscosity of $1\%$ sodium alginate solution was almost inversely proportional to the M/G and/or M block ratio. Viscosities were marked maximum from summer to autumn and minimum winter to spring. In the value of lower M/G and M block ratio, the viscosity seemed to have a considerable dependence on temperature. The temperature dependence was more appearant in the alginic acid from the frond (M/G ratio, 0.95; M block, $54.2\%$) collected in July and the stipe (M/G ratio, 1.61; M block $47.6\%$) in April. The affinity with metallic ion appeared higher in order of $Pb^{2+}>Cu^{2+}>Co^{2+}>Zn^{2+}$. The amounts of metallic ion exchange of the $Pb^{2+},\;Cu^{2+},\;Co^{2+}\;and\;Zn^{2+}$ were ranged from 3.4. to 4.7, 2.5 to 3.2, 1.8 to 2.2 and 1.6 to 1.7 meq/(g. sodium alginate), respectively.

• Journal of the Korea Computer Industry Society
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• v.6 no.5
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• pp.757-766
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• 2005

There have been great demands for higher density SRAM in all area of SRAM applications, such as mobile, network, cache, and embedded applications. Therefore, aggressive shrinkage of 6T Full CMOS SRAM had been continued as the technology advances, However, conventional 6T Full CMOS SRAM has a basic limitation in the cell size because it needs 6 transistors on a silicon substrate compared to 1 transistor in a DRAM cell. The typical cell area of 6T Full CMOS SRAM is $70{\sim}90F^{2}$, which is too large compared to $8{\sim}9F^{2}$ of DRAM cell. With 80nm design rule using 193nm ArF lithography, the maximum density is 72M bits at the most. Therefore, pseudo SRAM or 1T SRAM, whose memory cell is the same as DRAM cell, is being adopted for the solution of the high density SRAM applications more than 64M bits. However, the refresh time limits not only the maximum operation temperature but also nearly all critical electrical characteristics of the products such as stand_by current and random access time. In order to overcome both the size penalty of the conventional 6T Full CMOS SRAM cell and the poor characteristics of the TFT load cell, we have developed $S^{3}$ cell. The Load pMOS and the Pass nMOS on ILD have nearly single crystal silicon channel according to the TEM and electron diffraction pattern analysis. In this study, we present $S^{3}$ SRAM cell technology with 100nm design rule in further detail, including the process integration and the basic characteristics of stacked single crystal silicon TFT.

• Journal of Multimedia Information System
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• v.1 no.2
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• pp.111-118
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• 2014

The Smart grid refers to the technology that enables efficient usage of electric power by collecting information concerning the power usage and power lines grafting information and communications technology to onto power grids. There are Zigbee, PLC or IEEE 802.11 WLAN MAC as a core technology of the Smart grid, but in this paper, the discussion is focused on the PLC. The PLC is the technology that carries out data communications using power lines and put into practical use in the field of lights or home appliances control recently but PLC-applied communications between electronic devices are rarely seen. For the reason that the PLC uses high-voltage power lines and has a disadvantage of experiencing higher data loss rate caused by the noises produced by going through transformers, the technology is yet to be used in many areas. Nevertheless, the PLC has been studied widely recently in respect that it's the low-cost communication solution for the Smart Metering [1]. Moreover, this technology is emerging as a novel data communication method and discussed as an important technology lately due to the developments of the Smart grid systems and Internet of things (IoT). Thus, in this paper, the results obtained from designing and performing implementation scenario for the PLC-based Smart grid home network system were compared and analyzed with that of IEEE 802.11 WLAN MAC (the foundation technology at Jeju Smart grid Test bed)-based Smart grid home network. Thus, in this paper, OPNET 14.5 PL8, OSI 7 layer, PLC router nodes and PLC nodes had been used for the designing and implementation simulations of both systems. Additionally, QoS was not considered in order to guarantee that all the traffics would not have the same processing priority.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.4
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• pp.314-321
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• 2006

There have been great demands for higher density SRAM in all area of SRAM applications, such as mobile, network, cache, and embedded applications. Therefore, aggressive shrinkage of 6 T Full CMOS SRAM had been continued as the technology advances. However, conventional 6 T Full CMOS SRAM has a basic limitation in the cell size because it needs 6 transistors on a silicon substrate compared to 1 transistor in a DRAM cell. The typical cell area of 6 T Full CMOS SRAM is $70{\sim}90\;F^2$, which is too large compared to $8{\sim}9\;F^2$ of DRAM cell. With 80 nm design rule using 193 nm ArF lithography, the maximum density is 72 Mbits at the most. Therefore, pseudo SRAM or 1 T SRAM, whose memory cell is the same as DRAM cell, is being adopted for the solution of the high density SRAM applications more than 64 M bits. However, the refresh time limits not only the maximum operation temperature but also nearly all critical electrical characteristics of the products such as stand_by current and random access time. In order to overcome both the size penalty of the conventional 6 T Full CMOS SRAM cell and the poor characteristics of the TFT load cell, we have developed S3 cell. The Load pMOS and the Pass nMOS on ILD have nearly single crystal silicon channel according to the TEM and electron diffraction pattern analysis. In this study, we present $S^3$ SRAM cell technology with 100 nm design rule in further detail, including the process integration and the basic characteristics of stacked single crystal silicon TFT.

• Proceedings of the KSRS Conference
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• v.1
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• pp.253-256
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• 2006

When the background tropospheric ozone column over the Pacific Ocean is subtracted from the latitudinal total ozone distribution, the results show remarkable agreement with the latitudinal stratospheric ozone distribution using the CCD. The latitudinal tropospheric ozone distribution using the CCD method, with a persistent maximum over the southern tropical Atlantic, is also seen in the latitudinal tropospheric ozone distribution using the T-P method. It suggests that the CCD method can be replaced by the simple T-P method. However, the tropical Atlantic paradox exists in the results of both the CCD and T-P methods during the northern burning season. In order to investigate this paradox, we compare the latitudinal ozone distributions using the CCD and T-P methods by using the SAGE measurements (e.g. TSA method) and the SHADOZ ozonesoundings (e.g. T-S method) assuming zonally invariant stratospheric ozone, which is the same assumption as of the CCD method. During the northern burning season, the latitudinal distributions in the tropospheric ozone derived from the T-SA and T-S methods show higher tropospheric ozone over the northern tropical Atlantic than the southern Atlantic due to a stronger gradient in stratospheric ozone relative to that from the CCD and T-P methods. This indicates that the latitudinal tropospheric ozone distribution can be changed depending on the data that is used to determine the latitudinal stratospheric ozone distribution. Therefore, there is a possibility that the north-south gradient in stratospheric ozone over the Atlantic can be a solution of the paradox.

• Macromolecular Research
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• v.14 no.2
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• pp.173-178
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• 2006

Poly(3-(2-hydroxyethyl)thiophene) (P3HET) was synthesized using oxidative coupling polymerization that involved the protecting and deprotecting of hydroxyl groups but not the chlorine substitution or oxidative decomposition of the hydroxyl groups. The resulting P3HET exhibited good solubility in aprotic solvents, in contrast to the insoluble polymer product synthesized directly from the monomer, 3-(2-hydroxyethyl)thiophene (3HET). P3HET had low conductivity due to the strong hydrogen bonding of its hydroxyl groups. The ester-functionalized poly(3-(2-acetoxyethyl)thiophene) and poly(3-(4-pentylbenzoateethyl)thiophene) were also prepared with reasonably high molecular weights in order to examine how this functionalization modified the physical and chemical properties of P3HET. These polymers exhibited better solubility in common solvents and higher conductivity than P3HET. All these polymers exhibited bathochromic shifts of their film state absorption maxima with respect to those found in the UV-visible spectra of their solution phases. The extent of the bathochromic shift was found to vary with the lengths of the side chains of the ester-functionalized polymers.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.2
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• pp.153-160
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• 2017

Recently, the demand has continued to increase for higher data rates and improved multimedia services through wireless internet access. In order to increase the data rate and link reliability, 3GPP LTE/A and IEEE 802.16e/m WiMAX systems incorporate MIMO transmission schemes. Since the hardware complexity increases with the number of transmit data streams and mobile devices have limited physical dimensions, an multiple input multiple output (MIMO) ystem with two antennas at both the transmitter and the receiver ($2{\times}2$) is considered to be a possible solution for mobile devices. In this paper, a low-complexity soft output MIMO symbol detector based on Modified-SQRD is proposed for mobile devices with two transmit and two receive antennas.

• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.925-934
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• 1994

Nickel recovered from the spent oil-hydrogenation catalysts was used in hydrogenation catalyst preparation. The spent catalyst contains approximately 21.8% Ni, 0.7% Mg, and small quantities of Al, Fe, and Zn. Nickel recovery was obtained by inorganic acid digestion in the order of HCI>$NHO_3$>$H_2SO_4$. For $HNO_3$, 3hour extraction with 3N solution was satisfactory. In the PH range of 6.5~9.0, Ni recovery was higher, but metallic impurities were found to be coprecipitated. The PH in the range of 7.0~9.0 seems to be the optimum condition for separation to obtain acceptable Ni precipitates without the decrease of purity. The catalysts prepared with reclaimed nickel by wet reduction methods showed catalytic activities close to those prepared using reagent nickel in the oil hydrogenation reaction. The surface areas of the support do not seem to affect the catalytic activity.

• Journal of the Korea Concrete Institute
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• v.21 no.1
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• pp.21-27
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• 2009

In this study, experimental findings on the resistance to magnesium sulfate attack of portland cement mortar and paste specimens incorporating metakaolin (MK) are presented. Specimens with four replacement levels of metakaolin (0, 5, 10 and 15% of cement by mass) were exposed to solutions with concentrations of 0.424% and 4.24% as $MgSO_4$ at ambient temperature. The resistance of mortar specimens was evaluated through visual examination and linear expansion measurements. Additionally, in order to identify the products formed by magnesium sulfate attack, microstructural analyses such as XRD, DSC and SEM/EDS were also performed on the paste samples incorporating metakaolin. Results confirmed that mortar specimens with a high replacement level of metakaolin exhibited lower resistance to a higher concentration of magnesium sulfate solution. It was found that the negative effect of metakaolin on the magnesium sulfate attack is partially attributed to the formation of gypsum and thaumasite. Conclusively, it is necessary to pay a special attention when using metakaolin in concrete structures, particularly under highly concentrated magnesium sulfate environment.