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排序方式: 共有238条查询结果,搜索用时 26 毫秒
1.
井下抽油泵柱塞与泵筒运动规律的研究 总被引:1,自引:0,他引:1
用三元振动模型,综合考虑油柱、抽油杆柱和油管柱的振动.建立起数学模型并离散化,然后用微机编程求解微分方程组.对不同工况下的抽油泵运动规律和抽油机示功图进行分析研究,得出了油管应予锚定的结论,并给出了不同抽油机的适用范围.为进一步研究抽油泵的井下工作机理和故障原因打下了基础. 相似文献
2.
Fiber-optic reflex sensor for in-line production measurement 总被引:1,自引:0,他引:1
The paper describes experiments concerning distance measurement with fiber-optic sensor and improvement of the measurement principle. The sensor probe was well-designed with a small structure and multi-function. The novel optical fiber probe arrangement as well as the possibilities of use for complex measurement problems are explained using the measurement of an internal screw thread as an example. The experimental results show that the measurement uncertainty of the thread minor diameter can reach ±10 μm, and the stability of the measurement system is better than 0.07%. 相似文献
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4.
HL—1装置碳化和采用抽气孔栏时的可见辐射观测 总被引:1,自引:1,他引:0
本文描述了HL-1装置器壁碳化和采用抽气孔栏时,氢及杂质通量的变化情况;利用多道可见辐射的时空分布测量,得到了MARFE放电,在产生MARFE时,辐射热也相应增强。 相似文献
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Controllable growth and characterizations of hybrid spiral-like atomically thin molybdenum disulfide
Monolayer MoS2 is an emerging two-dimensional semiconductor with wide-ranging potential applications in novel electronic and optoelectronic devices. Here, we reported controlled vapor phase growth of hybrid spiral-like MoS2 crystals investigated by multiple means of X-Ray photoemission spectroscopy, scanning electron microscopy, atomic force microscopy, kelvin probe force microscopy, Raman and Photoluminescence techniques. Morphological characterizations reveal an intriguing hybrid spiral-like MoS2 feature whose lower planes are AB Bernal stacking and upper structure is spiral. We ascribe the hybrid spiral-like structure to a screw dislocation drive growth mechanism owing to lower supersaturation and layer-by-layer growth mode. In addition, the electrostatic properties of MoS2 microflakes with hybrid spiral structures are obvious inhomogeneous and dependent on morphology manifested by kelvin probe force microscopy. Our work deepens the understanding of growth mechanisms of CVD-grown MoS2, which is also adoptable to other TMDC materials. 相似文献
7.
Reza Torabi 《Physica B: Condensed Matter》2012,407(12):2109-2111
The effect of noise on the Dirac phase of electron in the presence of screw dislocation is studied. An uncorrelated noise, which coincides with the nature of thermal fluctuations, is adopted. Results indicate that the Dirac phase is robust against the existing noise in the system. 相似文献
8.
张昱 《科技情报开发与经济》2011,21(12):225-226
通过对无锡市梅梁湖泵站主水泵进行大修,系统总结了大修的准备、检查、安装工作,并对存在的问题提出了相关的建议。 相似文献
9.
《Particuology》2022
Screw conveyors are extensively used in modern industry such as metallurgy, architecture and pharmaceutical due to their high-efficiency in the transportation of granular materials. And substantial efforts have been devoted to the study of the screw conveyors. Numerical method is an effective way to study screw conveyor. However, previous studies have mainly focused in the regime of spherical particles while the in-depth investigations for non-spherical particles that should be the most encountered in practical applications are still limited. In view of the above situations, discrete element method (DEM), which has been widely accepted in simulating the discrete systems, is utilized to investigate the conveying process of non-spherical particles in a horizontal screw conveyor, with particles being modeled by super-ellipsoids. In addition, a wear model called SIEM (Shear Impact Energy Model) is incorporated into DEM to predict the wear of screw conveyor. The DEM simulation results demonstrate that the particle shape is influential for the flow behaviors of particles and the wear of conveyor. The conveying performance evaluated quantitatively of both mass flow rate and power consumption is subsequently obtained to investigate the effect of sphericity of particle with different operation parameters. Moreover, particle collision frequency and collision energy consumption are acquired to investigate the possible particle breakage between particles and screw blade. The comparisons between particle–particle collision and particle–wall collision reveal that particles with large shape index have more possibility to be damaged in particle–wall impingement. 相似文献
10.
乔建江 《河北省科学院学报》2011,28(1):35-38
介绍了天气雷达天线伺服控制系统中直流PWM泵升电压电路限制技术,泵升电压形成的原理以及泵升电压限制电路的原理,并结合工程设计中具体的直流PWM天线伺服控制系统对泵升电压限制电路的参数进行了详细的计算.较好的解决了供电电源的"泵升电压"对直流PWM伺服系统影响.实际应用表明,该天线伺服控制系统PWM保护电路设计是合理、成... 相似文献