• Environmental Engineering Research
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• 제23권2호
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• pp.159-163
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• 2018

The feasibility of applying coagulation-integrated microfiltration (MF) as a pretreatment for an ultrafiltration (UF) feed in oily wastewater treatment was investigated. The effects of different coagulants on oil removal rates from wastewater were studied. The maximum oil removal rate of 82% was obtained after coagulation with 130 mg/L of polyaluminium chloride (PAC). UF flux reached $95L/(m^2{\cdot}h)$ with coagulation-integrated MF as pretreatment. This value was 2.5 times higher than that flux obtained without pretreatment. The value of UF flux increased as the transmembrane pressure (TMP) and cross-flow velocity (CFV) of the UF module increased. UF flux gradually increased when TMP and CFV exceeded 0.4 MPa and 3 m/s, respectively, because of concentration polarization and membrane fouling stabilization. Chemical oxygen demand reduction and oil removal rate reached 95.2% and 98.5%, respectively, during integrated membrane processing with a PAC concentration of 130 mg/L, TMP of 0.4 MPa, and CFV of 3 m/s for UF. In addition, sequentially cleaning the fouling membrane with NaOH and $HNO_3$ aqueous solutions caused UF flux to recover to 90%. These encouraging results suggested that the hybrid integrated membrane process-based coagulation and MF + UF are effective approaches for oily wastewater treatment.

• Bulletin of the Korean Chemical Society
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• 제34권3호
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• pp.759-762
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• 2013

Four prominent features of Titan's haze are found within the '3.4-${\mu}m$' absorption to be uniform with recent vertically resolved Cassini/VIMS spectra. These are absorptions at 2998 $cm^{-1}$ (3.34 ${\mu}m$), 2968 $cm^{-1}$ (3.37 ${\mu}m$), 2927 $cm^{-1}$ (3.42 ${\mu}m$), and 2882 $cm^{-1}$ (3.47 ${\mu}m$). A detailed fitting suggests that the 2998 $cm^{-1}$ feature could originate from amorphous acetonitrile ($CH_3CN$) carrying about 25% of integrated optical depth; the remaining features, which account for 75% of the integrated optical depth, could arise from a distinct triplet (C-H stretching) structure of radiolyzed hydrocarbons. An additional feature was possibly evidenced at altitudes higher than 300 km and attributable to 'polymer-capped' methane ($CH_4$), significantly constraining the chemical composition of organic haze layers under Titan's active radiation field.

• JSTS:Journal of Semiconductor Technology and Science
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• 제13권5호
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• pp.423-429
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• 2013

A 6-Gb/s differential voltage mode driver is presented whose output impedance and pre-emphasis level can be controlled independently. The voltage mode driver consists of five binary-weighted slices each of which has four sub-drivers. The output impedance is controlled by the number of enabled slices while the pre-emphasis level is determined by how many sub-drivers in the enabled slices are driven by post-cursor input. A prototype transmitter with a voltage-mode driver implemented in a 65-nm CMOS logic process consumes 34.8-mW from a 1.2-V power supply and its pre-emphasized output signal shows 165-mVpp,diff and 0.56-UI eye opening at the end of a cable with 10-dB loss at 3-GHz.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제2권1호
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• pp.21-28
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• 1998

A total of 94 taxa were identified from the Southern Ocean, 140-148 $^{\circ}E$ and 40-53 $^{\circ}S$, as an early austral summer phytoplankton. They were 53 diatoms, 37 dinoflagellates, 2 silicoflagellates, 1 prymnesiophyte, and 1 coccolithophorid. Integrated cell numbers of nanoplankton dominated microphytoplankton from 8 stations, especially from Subantarctic zone, but integrated biomass was lower than microphytoplankton. Integrated cell numbers of diatoms dominated dinoflagellates, coccolithophorids, and prymnesiophyte, but integrated biomass of microphytoplankton were dependent to the biomass of dinoflagellates except north of the Subtropical convergence zone and south of the Antractic convergence zone. Phytoplankton community changed across the fronts and 3 different communities were observed. Fronts seem to influence on the phytoplankton community from the west Pacific Sector of the Southern Ocean.

• Membrane and Water Treatment
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• 제4권4호
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• pp.237-249
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• 2013

Ultra-pure water (UPW), a highly treated water free of colloidal material and of a conductivity less than 0.06 ${\mu}S$, is an essential component required by modern industry. One of the methods for UPW production is the electrodialysis-ion exchange (ED/IE) system, in which the electrodialysis (ED) process is used as a preliminary demineralization step. The IE step can be replaced with electrodeionization (EDI) to decrease the volume of post-regeneration lyes. In this paper, the electrodialysis process carried out to relatively low diluate conductivity was investigated and the costs of UPW production were calculated. The optimal value of desalination degree by ED in the ED/IE and ED/EDI systems was estimated. UPW unit costs for integrated ED/IE and ED/EDI systems were compared to simple ion exchange and other methods for UPW production (RO-IE, RO-EDI). The minimal UPW unit costs in ED/EDI integrated system were estimated as $0.37/$m^3$ for feed TDS 600 mg/L and $0.36/$m^3$ for feed TDS 400 mg/L at 64 $m^3/h$ capacity, which was lower than in the comparable ED/IE integrated system ($0.42-0.44/$m^3$). The presented results suggest that an ED/EDI integrated system may be economically viable.

• Journal of Information Display
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• 제2권2호
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• pp.1-6
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• 2001

A $1"{\times}l"$, $512{\times}512$ poly-Si TFT-LCD with a new integrated 8-bit parallel-serial digital data driver was proposed and designed. For high resolution, the proposed parallel-serial digital driver used serial video data rather than parallel ones. Thus, digital circuits for driving one column line could be integrated within very small width. The parallel-serial digital data driver comprised of shift registers, latches, and serial digital-to-analog converters (DAC's). We designed a $1"{\times}l"$, $512{\times}512$ poly-Si TFT-LCD with integrated 8-bit parallel-serial digital data drivers by a circuit simulator which has physical-based analytical model of poly-Si TFT's. The fabricated shift register well operated at 2 MHz and $V_{DD}$=10V and the fabricated poly-Si TFT serial DAC's, which converts serial digital data to an analog signal, could convert one bit within $2.8{\mu}s$. The driver circuits for one data line occupied $8100{\times}50{\mu}m^2$ with $4{\mu}m$ design rule.

• 대한기계학회논문집A
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• 제26권10호
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• pp.2187-2193
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• 2002

We present a novel method for 3D microfabrication with LIGA process that utilizes a deep X-ray mask in which a micro-actuator is integrated. The integrated micro-actuator oscillates the X-ray absorber, which is formed on the shuttle mass of the micro-actuator, during X-ray exposures to modify the absorbed dose profile in X-ray resist, typically PMMA. 3D PMMA microstructures according to the modulated dose contour are revealed after GG development. An X-ray mask with integrated comb drive actuator is fabricated using deep reactive ion etching, absorber electroplating, and bulk micromachining with silicon-on-insulator (SOI) wafer. 1mm $\times$ 1 mm, 20 $\mu$m thick silicon shuttle mass as a mask blank is supported by four 1 mm long suspension beams and is driven by the comb electrodes. A 10 $\mu$m thick, 50 $\mu$m line and spaced gold absorber pattern is electroplated on the shuttle mass before the release step. The fundamental frequency and amplitude are around 3.6 kHz and 20 $\mu$m, respectively, for a do bias of 100 V and an ac bias of 20 $V_{p-p}$ (peak-peak). Fabricated PMMA microstructure shows 15.4 $\mu$m deep, S-shaped cross section in the case of 1.6 kJ $cm^{-3}$ surface dose and GG development at 35$^{\circ}C$ for 40 minutes.

• 한국군사과학기술학회지
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• 제18권5호
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• pp.602-611
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• 2015

Even though GNSS provides highly accurate navigation information all over the world, it is vulnerable to jamming in the electronic warfare due to its weak signal power. The United States and Korea have plans to use terrestrial navigation systems as back-up systems during outage of GNSS. In order to develop back-up systems of GNSS, an M&S software platform is necessary for performance evaluation of various vehicle trajectories and integrated navigation systems. In this paper a design method of an M&S software is proposed for evaluation of multiple radio positioning integration systems. The proposed M&S software consists of a navigation environment generation part, a navigation algorithm part, a GUI part and a coverage analysis part. Effectiveness of the proposed design method is shown by implementing an M&S software for the GPS, DME and eLoran navigation systems.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권3호
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• pp.626-637
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• 2014

On ship, especially on large ship, the flexure deformation between Master (M)/Slave (S) Inertial Navigation System (INS) is a key factor which determines the accuracy of the integrated system of M/S INS. In engineering this flexure deformation will be increased with the added ship size. In the M/S INS integrated system, the attitude error between MINS and SINS cannot really reflect the misalignment angle change of SINS due to the flexure deformation. At the same time, the flexure deformation will bring the change of the lever arm size, which further induces the uncertainty of lever arm velocity, resulting in the velocity matching error. To solve this problem, a $H_{\infty}$ algorithm is proposed, in which the attitude and velocity matching error caused by deformation is considered as measurement noise with limited energy, and measurement noise will be restrained by the robustness of $H_{\infty}$ filter. Based on the classical "attitude plus velocity" matching method, the progress of M/S INS information fusion is simulated and compared by using three kinds of schemes, which are known and unknown flexure deformation with standard Kalman filter, and unknown flexure deformation with $H_{\infty}$ filter, respectively. Simulation results indicate that $H_{\infty}$ filter can effectively improve the accuracy of information fusion when flexure deformation is unknown but non-ignorable.

• 한국항공우주학회지
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• 제44권5호
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• pp.423-430
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• 2016

최근 국가공역 내 유 무인항공기 혼합운용 시 충돌 감지 및 회피, 통신두절 등의 다양한 문제가 예상된다. 따라서 본 연구에서는 EUROCONTROL의 BADA와 NASA의 성능 데이터를 기반으로 유인기와 무인기 혼합운용 및 ATC/ATM 시뮬레이션을 동시에 수행할 수 있도록 필요한 환경 구축과 동적 모델링을 수행하였다. 또한 구성한 모델의 검증을 위하여 6-DOF 비행모델과 세그먼트별 동일한 입력값으로 시뮬레이션을 수행하고, RMSE결과 비교를 통해 구성한 모델의 적합함을 확인하였다.