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21.
介绍一种新型的大功率精密交流伺服系统.此系统针对其它方案的不足,用交流变频调速器作功率输出器件直接驱动交流电机,用高精度轴角编码器作为位置检测器件,用16位单片机作控制器,构成数字化闭环控制,实现大功率精密位置伺服系统.此系统简便、经济、可靠,为变频调速器的应用开辟了新途径,为精密位过控制提供了新手段. 相似文献
22.
针对松软突出煤层钻进装备钻进与事故处理能力不足、体积大集成性差等问题,结合松软突出煤层瓦斯抽采钻孔施工需要,研制了ZDY5000RF型大功率两体式履带钻机。该钻机采用两体式安全布局,履带驱动行走,增加了安全防护系统和防护措施,整机功率达到75 kW,额定转矩达到5 000 N·m,给进起拔力达到210 kN。现场试验选择在淮北祁南煤矿进行,在f值为0.5左右的松软突出煤层中,完成孔深200 m以上钻孔5个。试验结果表明:该钻机具有功率大、体积小、搬迁方便、安全性高、钻进和事故处理能力强等等显著优点,在松软突出煤层中具备200 m深瓦斯抽采的钻孔施工能力,为松软突出煤层矿井瓦斯灾害治理提供了设备保障。 相似文献
23.
The high power light emitting diode (LED) array integrated with the microchannel heat sink is designed in this paper, and then optimal analysis and simulation have been carried out. According to the theory of heat transfer and fluid mechanics, the calculation of the thermal resistance for the microchannel heat sink is obtained, and the thermal resistance is minimized. Finally the simulation with FLUENT software is developed to verify the theoretical analysis.
Established analysis and simulation show that the width of the cooling channel is 0.1 mm, and the cooling water flow rate is 1 m/s. On the other hand, the system acquires the best heat dissipation effect, and the minimum of thermal resistance is 0.019 W/℃. 相似文献
24.
磷酸铁锂正极材料兼具安全性好、容量高且对环境友好等优点,成为目前最具潜力的动力电池正极材料之一。但其较低的电子导电率及离子电导率等缺点也十分明显。主要从磷酸铁锂正极材料本身的性能,包括倍率性能、能量密度、循环寿命和高低温性能方面分析了其实际应用于动力电池的潜力,以及结合国内外锂离子电池正极材料供应商情况简述了目前国内外磷酸铁锂产业化现状和趋势。 相似文献
25.
本文就越来越多的企事业单位使用大功率电源却缺乏有效校准手段的问题展开讨论,并通过研制校准装置(含高压和大电流两个模块),建立校准系统来解决问题。 相似文献
26.
27.
Artur Wiatrowski 《Vacuum》2008,82(10):1111-1114
It is well known that the magnetron self-sustained sputtering (SSS) process can be achieved in the direct current (DC) operation mode (DC-SSS) if certain conditions are fulfilled: high self-sputtering yield of the target material (theoretically Y>1), appropriate magnetron source design, high target power density to ensure high ionization level of the sputtered material. The main disadvantage of the DC-SSS process is the instability related to possibility of an arc formation. The author postulates that magnetron plasma pulsing can minimize this problem.In this paper, voltage and current waveforms of medium frequency (MF) powered magnetron source are analysed. A simple electrical model, explaining dynamics of MF magnetron discharge is presented. The method to achieve MF magnetron SSS process is proposed and experimentally verified. The results of MF magnetron SSS (MF-SSS) process are presented for the first time (to the author's knowledge). The experiments were performed using a planar magnetron source equipped with a copper target of 50 mm in diameter and 6 mm thick. The magnetron source was powered by a resonant (110 kHz) power supply. The target power density during MF-SSS process was about 490 W/cm2. 相似文献
28.
强激光热斑形成及其稳定性研究 总被引:2,自引:0,他引:2
在论述热点跟踪及其传热机理时将靶材的比热溶、热传导系、在激光的热藕合系数均考虑成温度和时间的函数,又考虑靶材在运动时将激光辐照物体时热点的建立及其稳定情况作一动态数值模拟,为热点跟踪作准备。 相似文献
29.
采用P型InP衬底新月型结构制备了1.48μm大功率激光器,该激光器与单模光纤耦合输出功率大于40mW。 相似文献
30.
《Ceramics International》2022,48(13):18716-18722
All-inorganic fluorescent materials with high luminescence efficiency, high thermal stability and adjustable spectrum are urgently needed, especially for high-power white LEDs. In this work, Y2.84Lu0.1Al5O12: 0.06Ce3+ fluorescent ceramics were prepared firstly by vacuum sintering technology, and then Y2.84Lu0.1Al5O12: 0.06Ce3+/SrAlSiN3: Eu2+ composite fluorescent ceramics were synthesized by technology screen-printing and laser ablation. Under 460 nm excitation, the composite fluorescent ceramic exhibits a broad emission band from 500 nm to 675 nm, which is attributed to the 5d → 4f transitions of Ce3+ and Eu2+ ions, respectively. By controlling the screen-printed times, the color coordinates of the composite fluorescent ceramics could be tuned from (0.3125, 0.2437) to (0.4106, 0.3824), and the correlated color temperature can vary from 3296 to 9689 K. In particular, the thermal stability of composite fluorescent ceramics is improved obviously after laser ablation. At 423 K, the luminescence intensity at 535 nm and 620 remains 91% and 94% of that at room temperature, respectively. Combining a 460 nm blue chip and the composite fluorescent ceramic, a white LED with CRI = 90, and the maximum luminous efficiency can be up to 148 lm/W. Our results indicate that Y2.84Lu0.1Al5O12: 0.06Ce3+/SrAlSiN3: Eu2+ composite fluorescent ceramics could be used in high-power white LEDs. 相似文献