C2用于声化学研究的大功率超声系统的研制

根据声化学反应的特殊要求，我们研制了用于声化学研究的大功率超声系统，由参数可调节的超声发生器配合不同频率的换能器工作，并用它组合成杯式变幅杆结构声化学反应器。解决了有关声化学设备的一些技术问题，为声化学技术从实验室规模向工业应用过渡做了必要的准备     

Compensation of birefringence in active elements with a novel Faraday mirror operating at high average power

A decrease in the depolarization ratio by more than one order of magnitude by use of a recently proposed Faraday mirror (FM) in comparison with the traditional FM has been demonstrated experimentally. At a high average laser power, the possibility of an increase in the accuracy of compensation of depolarization in the active element by means of a lambda/4 plate with both the traditional and the novel FM is shown.     

Design of a high power heater for the cryogenic hydrogen system at J-PARC

The cryogenic hydrogen system, which provides the supercritical hydrogen with the pressure of 1.5 MPa and the temperature of around 20 K, adopts to moderate and convert high-energy neutrons into cold neutrons for neutron scattering experiments in the J-PARC. Large pressure fluctuation caused by the intense pulsed-proton-beam injection and trip should be mitigated by both an active heater control and a passive accumulator control. A compact high power heater should be required to compensate the heat load corresponding to the nuclear heating while the proton beam stopping. In this study, the high power heater used in the cryogenic hydrogen was designed and a numerical analysis was performed. Then the results confirmed that the heater could apply kW-order heat powers to supercritical hydrogen without any disturbance.     

Design and development of high voltage high power operational amplifier using thick film technology

Applications of power operational amplifiers (opamps) are increasing day by day in the industry as they are used in audio amplifiers, Piezo transducer systems and the electron deflection systems. Power operational amplifiers have all the features of a general purpose opamp except the additional power handling capability. The power handling feature can be achieved using an external circuitry around a regular opamp. Normally power opamps can deliver current more than 50 mA and can operate on the supply voltage more than ±25 V. This paper gives the details of one of the power opamps developed to drive the Piezo Actuators for Active Vibration Control (AVC) of aircraft/aerospace structures. The designed power opamp will work on ±200 V supply voltage and can deliver 200 mA current.     

Total-reflection active-mirror amplifier for high pulse energy and high average power by using a composite ceramic

A total-reflection active-mirror (TRAM) amplifier is functionally designed by using a composite ceramic for high pulse energy and high average power. A chirped-pulse regenerative amplifier with a cryogenic TRAM has been successfully demonstrated as a feasibility study. A 3.5 mJ pulse energy is obtained at a repetition rate of 100 Hz. The corresponding energy fluence on the TRAM is as high as 1.5 J/cm² for 0.46 ns short pulses. The M²-factor is below 1.1 and no significant beam distortion is observed.     

Generation of subnanosecond 10-GHz pulses in high peak and high average power mode

The regime of excitation of microwave pulses in a 10-GHz range at a pulse duration of 0.8 ns and a peak power of ～2 GW has been studied in a relativistic backward wave oscillator with an extended periodic slow-wave system. A pulsed electron accelerator generating high-current electron beams (3 GW, ～600 keV, ～5 kA, 7 ns) at a repetition rate of 700 Hz and a pulse train width of 1 s has been developed based on a high-voltage generator with inductive energy storage, a semiconductor current interrupter, and a pulse-sharpening hydrogen-filled discharge gap. Optimization of the regime of the field-particle interaction allowed an average microwave power of 2.5 kW to be obtained at a transport magnetic field strength reduced below the cyclotron resonance value.     

Mode properties of off-axis one-sided hybrid resonator for novel high average power dual-slab laser

A novel dual-slab laser with off-axis one-sided hybrid resonator is presented. The mode properties of the hybrid resonator are calculated using a fast Fourier transform method (FFT). The influence of wavefront distoration on the output beam quality is considered. Results indicate that the novel dual-slab laser is better than the normal dual-slab laser with off-axis one-sided hybrid resonator.     

宽功率范围超声功率计的设计研究

设计了一种结合机械天平、辐射压力法和智能控制的大功率超声功率计，介绍该功率计的设计原理，对其误差进行分析，实验证实该功率计具有较好的稳定性、较高的测量精度和较大的测量范围。     

Different cooling configurations for a high average power longitudinally diode-pumped Yb:YAG amplifier

We analyze the temperature distribution in several Yb:YAG longitudinally pumped amplifier crystals by using various cooling configurations. The crystal designs are (i) a composite crystal made of a thin sheet of high-doped Yb:YAG bonded on a bulk piece of undoped YAG and (ii) a thick piece of low-doped Yb:YAG crystal. The cooling configurations investigated here include those both from the rear face or from the rear and side faces together. In every case we determine the average temperature rise, the longitudinal and radial temperature gradient, and the resulting crystal bending and optical phase distortion. We optimize the best cooling configuration and crystal design by compromising the average temperature, thermodeformation, and optical phase distortion. The experimental results also indicate that a thin sheet of gain medium (1.6 mm thick at 10 at. % doping) suffers from a notable bending deformation, which results in an unexpected decrease of the output energy.     

Effect of terbium gallium garnet crystal orientation on the isolation ratio of a Faraday isolator at high average power

We present a comprehensive and systematic investigation of the fundamental physical limitations of Faraday isolation performance at high average powers that are due to thermally induced birefringence. First, the operation of various Faraday isolator designs by use of arbitrary orientation of cubic magneto-optic crystals is studied theoretically. It is shown that, for different Faraday isolator designs, different crystal orientations can optimize the isolation ratio. Second, thermo-optic and photoelastic constants for terbium gallium garnet crystals grown by different manufacturers were measured. Measurements of self-induced depolarization are made for various orientations of crystallographic axes. The measurements are in good agreement with our theoretical predictions. Based on our results, it is possible to select a crystal orientation that optimizes isolation performance at high average powers, resulting in a 5-dB enhancement over nonoptimized orientations.     

Design criteria for high voltage leads for superconducting power systems

Future applications of superconductivity within power systems require reliable high voltage leads from ambient air into the LHe-region. The main electrical, thermal, and thermo-mechanical design criteria are discussed, and guiding rules are given for the construction of such leads. Practically feasible designs are described which are based on the experience with various tested prototype leads.     

超低功耗数据采集系统的设计

介绍以MSP430单片机为核心的数据采集系统。传感器输出的模拟信号经过信号调理电路后输送给单片机,由单片机完成数据采集任务。同时,单片机与上位机(PC)通讯,上位机可面向用户,因此可以由用户控制采集过程。该系统具有电路简单,精度高,超低功耗等特点,另外它还可以很方便地和一些应用广泛的核心处理器(如DSP、ARM)结合在一起来共同完成一个快速的数字信号处理过程或者实时的控制系统,因此,本系统的研究设计具有很好的实用价值。     

Design and analysis of folded channels for chip-based separations

Analytical methods are employed to investigate band broadening in a microchannel turn and adjoining straight channel segments for species transport by electrophoresis or electroosmotic flow. On the basis of closed-form solutions, we find that turn-induced broadening is negligible relative to total broadening when the radius of the turn exceeds some minimum. This minimum radius is about six-tenths of the product of the channel width and the Peclet number. We also find that the minimum radius is significantly reduced when a straight channel segment adjoins the turn in a folded configuration. Such straight segments noticeably reduce the minimum radius even for segment lengths comparable to the turn radius. The application of these results to folded and spiral channels is discussed, and sample calculations for practical conditions are presented. New pleated and coiled geometries for the compact layout of separation channels are also presented.     

Apparatus for quick control of materials by the damping capacity level

The article describes the working principle and design of an apparatus for quick control of damping capacity of materials in the amplitude-dependent region of internal friction with tension-compression loading of specimens in the ultrasonic range of frequencies (16–23 kHz). Amplitude dependences of energy dissipation parameters and modulus of elasticity defects of a series of metallic materials are presented as illustration.Translated from Problemy Prochnosti, No. 11, pp. 119–121, November, 1990.     

Patent data as indicators of wind power technology development

This paper reports a study into the use of patent application numbers as indicators of technological development in the field of wind power technology. We show that patent information can be used to analyse the evolution and the level of maturity of this particular technology. The data is gained from databases available at the Swedish Patent and Registration Office (PRV). Three different segments of wind power technology; rotor form, regulation and pitch adjusting, are distinguished and maturity in respective parts is compared to the general technological progress.     

Scaling up of a high average power dye laser amplifier and its new pumping designs

Scaling up of a high average power dye laser amplifier is discussed. Differences in the characteristics between a high average power dye laser amplifier with transverse pumping and longitudinal pumping are presented by a simple theory and simulations. The simulation results for dye laser amplifiers of 10-kW average output power show that longitudinal pumping is as efficient as transverse pumping with the potential of orders of magnitude lower dye flow rate. New pumping designs are also proposed for a dye laser amplifier aimed to achieve high gain with high efficiency to reduce the number of amplifier stages. Simulation results suggest that the new designs, in comparison with a conventional amplifier, can produce several orders of magnitude higher gain without decreasing the conversion efficiency.     

Design,development and performance characteristics of a large aperture disc amplifier for high power Nd: Glass laser chain

A large aperture disc amplifier has been designed, set-up and characterized for its performance on small signal gain, spatial variation of gain, and thermal recovery time. This amplifier, consisting of three elliptical Nd: phosphate glass discs of size 214 × 114 × 20 mm mounted at Brewster angle and pumped by ten xenon filled flash lamps of 600 mm arc length, provided a small signal gain of 6 at electrical pump energy of 36 kJ (in a pulse of 450 μs) using an in-house developed dual-polarity capacitor bank based power supply. It was coupled to a high power Nd: phosphate glass laser chain and a maximum output pulse energy exceeding 100 J in a 1·5 ns (FWHM) pulse has been measured. A dry nitrogen gas based cooling system was developed for cooling the glass discs with a thermal recovery time of ∼ 20 minutes.     

随钻声波测井仪高效电源设计

为了保障随钻声波测井仪在锂电池供电条件下能够长时间工作,需要采用高效电源设计。根据随钻声波电子系统的供电特点、电池性能和工程应用要求,设计了随钻声波测井仪电源控制电路。随钻声波测井仪采用间歇工作方式,低功耗微处理器根据随钻测量系统的指令控制电源开关,对仪器主电子系统的电源进行控制。仿真和实验结果表明,电源控制电路功耗低、抗干扰能力强、可靠性高,能够满足随钻声波测井仪的工作要求。