AC side harmonic and phenomena accompanying DC-injection of utility-interactive PV system

The experiments investigated phenomena related to direct contact between the DC output of a PV array and the AC power from the utility grid. The results show that the DC power flows through the distribution transformers (DC-injection) saturating their magnetic circuits. The saturation of magnetic circuits makes peak currents, incorporating a large portion of even harmonics, flow through the high-voltage side of the distribution transformer, adding the level of harmonic distortion of its exciting current. With the increase of injecting DC-current to the utility grid, peak currents at the primary side of distribution transformer increases the most, and even among the same effective (rms) values, the increase of primary side current is larger than that of the secondary side current.     

Source-synchronization and timing vernier techniques for 1.2-GB/sSLDRAM interface

This paper describes a validation system for an SLDRAM interface. The SLDRAM system utilizes two techniques to achieve a high data-transfer rate with a conventional module mounting style. The first technique is a source-synchronization scheme. Since the chip that transmits data also supplies the data clock, the clock and data are completely synchronous. The second is the timing vernier technique. A wait time for output data is programmable in each SLDRAM. Therefore, the time at which data arrive at the controller from any SLDRAM can be set by the controller with a 200-ps step size. The validation chip is designed to emulate these operations. The chip is fabricated using a 0.35-μm CMOS process technology and packaged in a conventional 0.65-mm pitch thin small out-line package, mounted on a single-chip module, and put into an eight-module system. A stub series terminated logic (SSTL)-like interface is adopted for high-speed signals. From system-level measurements, the data eye width of 600 ps is obtained at a data rate of 600 Mbps. Errorless data transmission is observed in both read and write operations in a bit-error rate testing. The validation system has successfully demonstrated a data-transmission rate of 1.2 GB/s (600 Mbit/s/pin) using source-synchronization and timing vernier techniques at the supply voltage of 2.5 V     

Theoretical limitations of a Hopfield network for crossbarswitching

It has been reported through simulations that Hopfield networks for crossbar switching almost always achieve the maximum throughput. It has therefore appeared that Hopfield networks of high-speed computation by parallel processing could possibly be used for crossbar switching. However, it has not been determined whether they can always achieve the maximum throughput. In the paper, the capabilities and limitations of a Hopfield network for crossbar switching are considered. The Hopfield network considered in the paper is generated from the most familiar and seemingly the most powerful neural representation of crossbar switching. Based on a theoretical analysis of the network dynamics, we show what switching control the Hopfield network can or cannot produce. Consequently, we are able to show that a Hopfield network cannot always achieve the maximum throughput.     

A new perspective on the characterization of materials for a-Si:H solar cells

A study has been carried out on a-Si:H solar cell materials fabricated under a wide range of deposition conditions in different laboratories. The results on both thin films and corresponding Schottky barrier cell structures demonstrate that analysis and characterization based solely on the neutral dangling bonds are clearly inadequate. Contributions of charged defects to the properties of a-Si:H, their effect on light-induced changes are identified together with the limitations of methods commonly used to characterize the solar cell properties and stability of a-Si:H materials. Self-consistent fitting of a wide range of results on films and Schottky barrier cell structures is obtained with a gap state distribution in which charged defects are included.     

Power system voltage control by distributed expert systems

A case study of the application of a distributed control scheme to a power system control is presented. In addition, an investigation has been conducted into voltage control. Combined injection of VAr-compensating devices controlled by distributed expert systems has been proposed as a measure to maintain voltage stability in a power system under heavy loading conditions. A simulation study has been carried out by using five workstations that represent a power system and four VAr-compensating devices. The results demonstrate the effectiveness of the proposed system for voltage recovery     

Stress-Induced Resistivity Anomaly in Semiconducting Barium Titanate Ceramic Wire

Thin, semiconducting BaTiO₃ ceramic wires prepared in the present study exhibited reversible stress-induced, nonlinear current—;voltage characteristics across several grain boundaries. A remarkable change in resistance with the application (by the three-point bending method) of only ∼1% tensile deformation indicated that the BaTiO₃ wires may have potential as stress-sensing devices. Resistance in the BaTiO₃ wires bot increased and decreased with increasing tensile stress parallel to the electric fields, far below the ferroelectric transition temperature, T _c; in Sr-substituted wires near T _c, on the other hand, resistance only increased. Detailed studies of the patterns and fluctuation of polarization at grain boundaries could be meaningful, because stress-sensing characteristics may be induced by changes in the relative angle between polarization vectors of adjacent grains.     

Radiation source dependence of performance degradation in thin gate oxide fully-depleted SOI n-MOSFETs

The degradation of the electrical performance of thin gate oxide fully depleted SOI n-MOSFETs and its dependence on the radiation particles are investigated. The transistors are irradiated with 7.5-MeV protons and 2-MeV electrons at room temperature without bias. The shift of threshold voltage and the coupling effect with the degraded opposite gate are clarified. A remarkable reduction of the floating body effects is observed after irradiation. The degradation of the extracted parameters is discussed by a comparison with the damage coefficients.     

采用无偏振片反射式LCD及超低功耗驱动技术制造移动显示器件

我们通过对材料和制备条件的精细化处理,生产出一种在低刷新频率下无闪烁和图像迟滞现象的反射式显示器。该显示器的功耗非常低,且可在宽温度范围内工作,是未来移动显示器件的潜力平台。