多孔挡板流化床还原UO3反应器模型的研究

针对ＵＯ＿３的Ｎ＿２还原反应建立了多孔挡板流化床反应器模型。将多孔挡板床的每一级视为具有相似的流动状态，每一级的上、下段称为稀、密相段，分别用鼓泡床和活塞流模型描述。该模型的计算值与￠６３ｍｍ的多孔挡板床Ｈ＿２还原ＵＯ＿３的热态实验值能较好的吻合。还预计了还原温度、操作气速和挡板结构参数对固相转化率的影响，为该类反应器的工业设计、放大和优化提供了依据。     

Observation of atomic steps on CaCO3 crystal surface

By using scanning polarization force microscopy,the deliquescence process and the atomic steps on the cleavage surface of CaCO3 in air were studied in situ.Under an exposure to medium umidity(-57%),the sloiw step movement has been observed.     

Multimedia Signal Processors: An Architectural Platform with Algorithmic Compilation

Novel algorithmic features of multimedia applications and advances in VLSI technologies are driving forces behind the new multimedia signal processors. We propose an architecture platform which could provide high performance and flexibility, and would require less external I/O and memory access. It is comprised of array processors to be used as the hardware accelerator and RISC cores to be used as the basis of the programmable processor. It is a hierarchical and scalable architecture style which facilitates the hardware-software codesign of multimedia signal processing circuits and systems. While some control-intensive functions can be implemented using programmable CPUs, other computation-intensive functions can rely on hardware accelerators.To compile multimedia algorithms, we also present an operation placement and scheduling scheme suitable for the proposed architectural platform. Our scheme addresses data reusability and exploits local communication in order to avoid the memory/communication bandwidth bottleneck, which leads to faster program execution. Our method shows a promising performance: a linear speed-up of 16 times can be achieved for the block-matching motion estimation algorithm and the true motion tracking algorithm, which have formed many multimedia applications (e.g., MPEG-2 and MPEG-4).     

Mixing in processing of thermoplastics by extrusion

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 8, pp. 9–11, August, 1993.     

Broadcast digital subscriber lines

The adoption of asymmetrical digital subscriber lines (ADSL) technology in conjunction with the broadcast digital subscriber lines (BDSL) proposed in this paper could provide a cost effective solution for the introduction of digital video services in the near term. BDSL provides the same digital broadcast video programs to all subscribers through existing twisted pair telephone loops. In this paper, the basics of telephone loop-based digital subscriber lines are first discussed. Then the potential of BDSL is explored in the twisted pair loop plant near end crosstalk (NEXT), far end crosstalk (FEXT), and white noise environment. The capability of BDSL is examined with different serving areas and transmit power levels. The possibility of using orthogonal quadrature amplitude modulation (QAM) to implement a zero guard-band BDSL system is studied. Computer BDSL performance simulations are then presented. The combination of high-bit-rate digital subscriber lines (HDSL), ADSL, and BDSL can provide telephone subscribers many digital broadband services     

A soft switching active snubber optimized for IGBT's in singleswitch unity power factor three-phase diode rectifiers

This paper describes a soft switching active snubber for an IGBT operating in a single switch unity power factor three-phase diode rectifier. The soft switching snubber circuit provides zero-voltage turn-off for the main switch. The high turn-off losses of the IGBT due to current tailing are reduced by zero-voltage switching. This allows the circuit to be operated at very high switching frequencies with regulated DC output voltage, high quality input current and unity input power factor. Simulation and experimental results are included     

Applications of ultrashort pulse propagation in Bragg gratings forwavelength-division multiplexing and code-division multiple access

We discuss theoretical and experimental studies on the propagation of ultrashort pulses through fiber Bragg gratings. We also consider several applications in optical communications to be found by combining ultrashort pulses and fiber Bragg gratings: a multiwavelength source for wavelength-division-multiplexed systems and a means for implementing optical code-division multiple access     

COIL中BHP浓度对发生O_2(~1△)的影响

本文实验研究了BHP的浓度对产生O2（1△）的影响。实验结果表明：当BHP浓度大于3.5M时，Cl2利用率以及O2（1△）的产率将不依赖于BHP浓度的变化而变化，同时，实验结果表明，使用低浓度的BHP对COIL的操作是可行的。     

Transient behavior of subthreshold characteristics of fullydepleted SOI MOSFETs

It has been found that the subthreshold currents of fully depleted silicon-on-insulator (SOI) MOSFETs show a transient behavior under certain front-gate and back-gate voltage conditions. The cause of this anomaly is explained, and applications for the phenomenon are pointed out. Particularly, a simple way to measure the silicon film thickness is suggested