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.     

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     

X-ray and ion emission characteristics of plasmas ablated from solid materials using a high power Nd:Glass laser

X-ray and ion emissions from high temperature plasmas from solid targets with different atomic numbers have been studied. Plasma is generated using a high power Nd:Glass laser generating focused intensity in the range of 10¹² to 10¹³ Watts/cm² on targets. Plasma temperature is typically between 50 to 100 eV. X-ray emission scaling as a function of laser intensity as well as ion velocity has been measured in these targets. Non-uniform plasma expansion and generation of fast ions are observed for targets with higher atomic numbers.     

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。     

Design and performance characteristics of an electromagnetic interference shielded enclosure for high voltage Pockels cell switching system

An electro-magnetic interference noise shielding enclosure for Pockels cells for high speed synchronized switching has been set-up and tested. The shielding effectiveness of the aluminum enclosures housing the Pockels cells and the electronic circuitry has been measured using a high impedance probe and is found to be ∼50 dB. This ensures a noise-free and synchronized electro-optic switching in an Nd:glass re-generative amplifier of chirped pulse amplification based table top terawatt laser system. resigned from RRCAT     

涡轴发动机细长柔性转子动力特性及高速动平衡技术研究

摘要：建立了涡轴发动机动力涡轮转子动力特性有限元分析模型,计算得到了转子的前三阶临界转速值,在高速旋转试验器上完成了全转速范围内的动力特性和高速动平衡试验,实测得到了转子在额定工作转速范围内高速动平衡前和高速动平衡后等状态下振动幅值随转速的变化曲线,研究结果表明：建立的计算模型反映了转子的真实情况,高速动平衡效果良好,解决了型号研制过程中的一项关键技术。     

LASERIX: An open facility for developments of EUV and soft X-ray lasers and applications—Developments of XUV sources using high power laser facilities: ILE, ELI

LASERIX is a high-power laser facility leading to High-repetition-rate XUV laser pumped by Titanium:Sapphire laser. The aim of this laser facility is to offer Soft XRLs in the 30-7 nm range and auxiliary IR beam, which could also be used to produce synchronized XUV sources. In this contribution, the main results concerning both the development of XUV sources and their use for applications (irradiation of DNA samples) are presented, as well the present status and some perspectives for LASERIX.     

Threats and benefits of power discrepancies between organisations: a supply chain perspective

The discrepancy of power between organisations has raised concerns over the abuse of power in inter-organisational relationships, especially in the supply chain where parties often have different power positions. In this study, we develop and test a model that explains how the less powerful party may react to different forms of power exercised by the power source. Nowadays, customers are typically more powerful than manufacturers in supply chains. Specifically, based on data from 617 manufacturers representing various organisational sizes and industries, we examine the impact of customer coercive and expert power on the manufacturer’s information sharing behaviours (information systems and content) as well as the performance implications for both the manufacturer and the customer. Structural equation modelling reveals that customer expert power positively predicts the establishment of information systems and the extent to which information is actively shared. In contrast, customer coercive power is negatively associated with the establishment of information systems, while it is positively related to information content. Information systems, in turn, predict the extent to which information is effectively exchanged, which ultimately relates positively to flexibility and delivery performance. Flexibility performance is positively related to financial performance, while delivery performance is not. Taken together, these findings enrich our understanding of inter-organisational power dynamics by offering important insights into differential reactions that the power target may choose to counter power imbalances.     

热电厂采用热电冷联供的适用性分析

利用等效发电效率概念,以300MW级抽凝式供热机组为例,对热电冷联供的适用性进行分析。在目前电、热价格以及发电机组装备水平的基础上,提出城市热电厂推广使用热电冷联供的约束性条件。     

Design and fabrication of a diode-side-pumped Nd:YAG laser with a diffusive optical cavity for 500-W output power

A ray-tracing code has been developed, and the design parameters of the laser pump head were analyzed in terms of crystal diameter, doping concentration, and optical cavity diameter. According to the numerical analysis, we fabricated an efficient diode-pumped Nd:YAG laser and experimentally obtained 500-W output power. The output power is close to the numerically calculated output power of approximately 450 W and corresponds to an optical-to-optical conversion efficiency of 46.7% and an optical slope efficiency of 49%.     

Diode-pumped Nd:YAG master oscillator power amplifier with high pulse energy, excellent beam quality, and frequency-stabilized master oscillator as a basis for a next-generation lidar system

A pulsed, diode-laser-pumped Nd:YAG master oscillator power amplifier (MOPA) in rod geometry, frequency stabilized with a modified Pound-Drever-Hall scheme is presented. The apparatus delivers 33-ns pulses with a maximum pulse energy of 0.5 J at 1064 nm. The system was set up in two different configurations for repetition rates of 100 or 250 Hz. The beam quality was measured to be 1.5 times the diffraction limit at a pulse energy of 405 mJ and a repetition rate of 100 Hz. At 250 Hz with the same pulse energy, the M2 was better than 2.1. The radiation is frequency converted with an efficiency of 50% to 532 nm. This MOPA system will be the pump laser of transmitters for a variety of high-end, scanning lidar systems.     

Design and experimental investigation of a cryogenic system for environmental test applications

This paper is concerned with the design, development and performance testing of a cryogenic system for use in high cooling power instruments for ground-based environmental testing. The system provides a powerful tool for a combined environmental test that consists of high pressure and cryogenic temperatures. Typical cryogenic conditions are liquid hydrogen (LH2) and liquid oxygen (LO2), which are used in many fields. The cooling energy of liquid nitrogen (LN2) and liquid helium (LHe) is transferred to the specimen by a closed loop of helium cycle. In order to minimize the consumption of the LHe, the optimal design of heat recovery exchangers has been used in the system. The behavior of the system is discussed based on experimental data of temperature and pressure. The results show that the temperature range from room temperature to LN2 temperature can be achieved by using LN2, the pressurization process is stable and the high test pressure is maintained. Lower temperatures, below 77 K, can also be obtained with LHe cooling, the typical cooling time is 40 min from 90 K to 22 K. Stable temperatures of 22 K at the inlet of the specimen have been observed, and the system in this work can deliver to the load a cooling power of several hundred watts at a pressure of 0.58 MPa.     

一种实验用高温高尘气体灰分同时取样装置的研制

针对高温高尘环境中气体和灰分取样所面临的取样管融化烧断问题、堵塞问题和卤化碱凝结问题,提出一种实验用髙温高尘气体灰分同时取样装置。该装置由取样探头和过滤取样器两部分组成,其中采用三层水冷套管的取样探头解决取样管融化烧断问题,采用外部过滤取样器解决高尘导致的堵塞问题,采用烟气温度控制方法解决卤化碱凝结问题。     

Preparation and electrochemical performance of manganese oxide/carbon nanotubes composite as a cathode for rechargeable lithium battery with high power density

Manganese oxide/carbon nanotubes (MO/CNTs) composite was prepared by hydrothermally reducing KMnO₄ with CNTs, where the used CNTs are of dual role, i.e., they serve as reductant during reaction and the remaining CNTs act as conducting agent in the composite. This composite was characterized by X-ray diffraction and scanning electron microscopy techniques. In addition, the electrochemical performances of the composite were investigated, which suggested an excellent rate-capability of this material; e.g., it delivered a high discharge capacity as 131 mAh g^− 1 at a high current density of 4 A g^− 1 (20 C), and high capacity at low discharge current density, e.g., about 209 mAh g^− 1 at 0.2 C rate. Therefore, such a MO/CNTs composite is promising in high power application of lithium battery and electrochemical capacitor.     

A decision support framework for global supply chain modelling: an assessment of the impact of demand,supply and lead-time uncertainties on performance

We developed a decision support framework for a global manufacturer of specialty chemicals to study the relative impact of demand, supply and lead-time uncertainties on cost and customer service performance. Our approach combines optimisation and simulation methodologies as follows: mathematical models provide optimal plans via a novel approach to the supply chain planning mechanism of the Company. Simulation models execute the supply chain plans so as to allow the examination of the outcomes under the various sources of uncertainty. The iterative use of optimisation and simulation methodologies allows the user the benefit of obtaining optimal solutions while revealing the impact of uncertainties on system performance. Our results indicate that demand uncertainty has the greatest negative impact on performance for the supply chain that we modelled in this study, emphasising the importance of effective forecasting. The relative importance of supply and lead-time uncertainties varies according to the performance measures. While our results are valid for the specific supply chain and the operating environment we modelled, our study emphasises the importance of the ability to model supply chains realistically to obtain valid and useful results.     

Formulation development and human in vitro-in vivo correlation for a novel, monolithic controlled-release matrix system of high load and highly water-soluble drug niacin

Novel, controlled-release formulations for high drug load, highly water soluble compound niacin based on polyethylene oxide (PEO) and hydroxypropylmethyl cellulose (HPMC) matrices were developed and investigated. The effect of sodium bicarbonate as a modulator of swelling, erosion, and drug release and its impact on changes in the kinetics of axial swelling and gel strength were evaluated by textural analysis during dissolution study. The drug release rate from PEO-based matrices was faster and correlated with lower gel strength, greater water uptake, and greater matrix erosion. Slower release rate and greater release duration correlated significantly with greater matrix swelling with negligible matrix erosion for the HPMC-based matrix system. Inclusion of sodium bicarbonate in the polymeric matrix salted out the macromolecules and increased gel strength and gel viscosity, especially in the vicinity of the swelling fronts. An in vivo study in human subjects after administration of the formulations and a commercial product exhibited similar plasma concentrations. For the formulation of interest, the mean drug fraction absorbed by the body was calculated by the Wagner-Nelson technique, and a level A “in vitro-in vivo correlation” was observed between the percent released in vitro and percent absorbed in vivo. The developed formulations appear to be robust and easy to manufacture with maximum flexibility with respect to drug dose, polymeric carriers, duration, and kinetics of drug release.