Fluorescence in situ hybridization and INT-dehydrogenase activity test to assess the effect of DO concentration in aerobic biofilm reactor

To assess the effect of DO concentration in aerobic biofilm reactor, we investigated the bacterial communities and their activity utilizing the combination of two methods, fluorescence in situ hybridization (FISH) and INTdehydrogenase activity test. D-1, D-2, D-3 and D-4 reactor with different DO concentrations (1, 3, 5 and 7 mg/L, respectively) were set up in the thermostat and acclimated. The optimal DO concentration with stable nitrification efficiency in aerobic biofilm reactor was above 5.0 mg/L. FISH method showed us that higher DO concentration led to the increase of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria ratios and the decrease of heterotrophs ratio. The INT-DHA activities of each reactor were 203, 153, 36 and 45 mgO₂^*/g VSS/day, respectively. The INT-DHA activities in D-1 and D-2 reactors were higher than those of D-3 and D-4 reactors, which indicates that filamentous microorganisms affected the INT-DHA activity. In the case of D-3 and D-4 reactors, as nitrification efficiency increased, INT-DHA activity also increased. In the relationship between the attached biomass and nitrification efficiency, only active biomass influenced the nitrification efficiency.     

Significance of coating stress on substrate bow in large areaprocessing of MCM

The substrate bow in a large area processing (LAP) was simulated using a finite element analysis (FEA). The structures considered were aluminum (Al) and glass substrates of various thicknesses, and a coating from Photosensitive film thickness. It was found that the deflection of a large area substrate, e.g., 400 mm², could not always be obtained from the linear, small deflection theory even if the curvature might be small and the stress-strain behavior in the linear elastic regime. In this case, the nonlinear, large deflection theory had to be adopted. Also, the gravity effect from the substrate weight turned out to be very significant and had to be incorporated as well. The simulation incorporating these two factors agreed well with the experimental data, which was generated by spin coating and curing the BCB formulation on Al substrates, 400×400×1.27 mm. As a means of flattening out the curvature, subjecting a vacuum underneath the substrate was simulated. Significant reduction of the substrate deflection was observed by applying only a very small vacuum. This result suggested that the use of double-stick tape on the bottom of the substrate, for example, might also of feasible to completely eliminate the bow     

Primary network cognition with spatial diversity signature

The identification of primary networks improves efficiency in dynamic spectrum access. We propose a spatial diversity signature for the primary signal detection, which exploits the structure of space-time or space-frequency codeword based on Alamouti scheme. The signature pattern informs the secondary user which network transmits the primary signal and enables to maintain an experiential database for each primary network. The proposed scheme provides reliable detection and network identification performance over frequency-selective fading channels in low signal-to-noise ratio regimes, without sacrificing the data rate of primary system.     

Fabrication and characterization of Au/SBT/LZO/Si MFIS structure

Ferroelectric SrBi₂Ta₂O₉ (SBT) films on a p-type Si (100) wafer with a LaZrO _x (LZO) buffer layer have been fabricated to form a metal-ferroelectric-insulator–semiconductor (MFIS) structure. The LZO thin film and SBT films were deposited by using a sol–gel method. The equivalent oxide thickness (EOT) value of the LZO thin film was about 8.83 nm. Also, the leakage current density of the LZO thin film is about 3.3?×?10^?5 A/cm² at bias sweeping voltage of ±5 V. SBT films were crystallized in polycrystalline phase with highly preferred (115) orientation. Also, the intensity of each pick slightly increased as thickness of SBT films increased. The C–V characteristics of Au/SBT/LZO/Si structure showed clockwise hysteresis loop. The memory window width increased as the thickness of SBT films increased. The leakage current density of Au/SBT/LZO/Si structure decreased as thickness of SBT films increased.     

Performance analysis of smart antenna test-bed operating in awide-band CDMA channel

In this paper, we present a performance analysis of a smart antenna system operating in a wide-band CDMA wireless-local-loop channel using a beam-forming module (BFM) that has been implemented on a digital signal processor (TMS320C6701) board. We first show the results of computer simulations obtained from the modeled received (RX) signals through a test-bed system consisting solely of baseband signal processing parts, i.e., modeled RX data-generating PC, BFM for computing the optimal weight vector and interfacing module. A test-bed system of the entire base station is then implemented to evaluate the adaptive beam-forming function with the actual wireless signals. This test-bed system includes several subscribers, as well as the array antenna, RF modules, and other receiving parts required at the cell site     

Pilot Position Selection and Detection for Channel Estimation of SC-FDE

In this letter, we propose a simple pilot position selection/detection technique for channel estimation of single- carrier frequency domain equalization (SC-FDE). Unlike the conventional channel estimation techniques such as frequency domain superimposed pilot technique (FDSPT), the proposed scheme selects the pilot positions to minimize the distortion of original signals caused by the loss of useful data tones in frequency domain. The corresponding receiver structure is also presented, where the pilot positions are blindly detected and the distorted data symbols are iteratively reconstructed. Simulation results show that the proposed system gives better BER performance than the FDSPT and approaches the lower bound of SC-FDE.     

Frequency domain pilot multiplexing technique for channel estimation of SC-FDE

A frequency domain pilot multiplexing technique for channel estimation of single-carrier frequency domain equalisation (SC-FDE) is proposed. The proposed scheme selects pilot positions to minimise the pre-imposed distortion caused by the loss of useful data tones. The corresponding receiver structure is also presented, where the pilot positions are blindly detected and the distorted data symbols are iteratively reconstructed. Simulation results show that the proposed system approaches the lower bound of SC-FDE.     

Chemically grown, porous, nickel oxide thin-film for electrochemical supercapacitors

A porous nickel oxide film is successfully synthesized by means of a chemical bath deposition technique from an aqueous nickel nitrate solution. The formation of a rock salt NiO structure is confirmed with XRD measurements. The electrochemical supercapacitor properties of the nickel oxide film are examined using cyclic voltammetery (CV), galvanostatic and impedance measurements in two different electrolytes, namely, NaOH and KOH. A specific capacitance of ∼129.5 F g⁻¹ in the NaOH electrolyte and ∼69.8 F g⁻¹ in the KOH electrolyte is obtained from a cyclic voltammetery study. The electrochemical stability of the NiO electrode is observed for 1500 charge-discharge cycles. The capacitative behaviour of the NiO electrode is confirmed from electrochemical impedance measurements.     

Fuzzy algorithm for calculating roll speed variation based on roll separating force in hot rolling

Thickness control of hot-rolled strips has become an important issue in recent years because of the need for improving the quality of the hot-rolled strip. For this purpose, various thickness control systems such as finishing mill set-up (FSU), automatic gauge control (AGC), and looper control system, have been developed at steel works. Although these systems have greatly improved the quality of the strip thickness, there still exists a small amount of thickness deviation. It is difficult to adequately control by applying conventional thickness control techniques since hot rolling process is a highly nonlinear system in which many process parameters are coupled. In this study, a fuzzy algorithm to calculate the roll speed variations was developed in order to improve the thickness uniformity of hot-rolled strips. Since the strip thickness is mostly affected by the magnitude of roll separating force depending on the roll speed, the strip thickness deviation between the desired and actual thicknesses can be reduced by controlling roll speed. In order to carry out this investigation, slab analysis was carried out to determine the relation between roll separating force and roll speed for various process parameters such as roll speed, reduction ratio, strip entry thickness, and front and back tensions. From the production data, the effective stress-strain rate relations of the materials used in slab analyses were acquired. Based on the analytical results, the relation between roll separating force and roll speed was approximated by a log function. A fuzzy algorithm was developed to determine variations in roll speed according to variations of roll separating force, depending on various ranges of rolling temperature, reduction ratio, front and back tensions, and strip thickness. In addition, simulations to predict roll speed variations for a small amount of thickness deviation were carried out at continuous finishing mills consisting of seven stands and the calculated roll speed variations were found to be reasonable. Thus, the developed fuzzy algorithm might be useful in reducing the thickness deviation in the actual hot rolling mills.