排序方式: 共有78条查询结果,搜索用时 453 毫秒
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将现代数字逻辑电路基本逻辑运算采用硬件描述语言描述。本文用Verilog HDL语言描述与运算、或运算和非运算,并给出了应用实例。将数字逻辑运算表示成硬件语言描述,具有格式统一、简洁的作用,便于阅读理解和修改。采用硬件语言描述方法更易于提高数字电路与系统设计能力,加强创新实践活动。 相似文献
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从噪音产生机理、谐波电流的影响、直流电流的影响等对主变压器噪音异常现象进行了分析。直流入侵时会产生直流偏磁现象,随着直流分量的增大,励磁电流畸变越来越严重,并出现严重的半周饱和,从而对变压器产生严重危害。通过分析,确认驿南府变电站主变压器异常噪音为直流电流的影响,为解决这些问题,提出了串联电阻、串联高压电容器等解决的方案。实践证明了这些方案的有效性。 相似文献
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In order to study the major performance indicators of the twin-rotor piston engine(TRPE), Matlab/simulink was used to simulate the mathematical models of its thermodynamic processes. With consideration of the characteristics of the working processes in the TRPE, corresponding differential equations were established and then simplified by period features of the TRPE. Finally, the major boundary conditions were figured out. The changing trends of mass, pressure and temperature of working fuel in the working chamber during a complete engine cycle were presented. The simulation results are consistent with the trends of an actual working cycle in the TRPE, which indicates that the method of simulation is feasible. As the pressure in the working chamber is calculated, all the performance parameters of the TRPE can be obtained. The major performance indicators, such as the indicated mean effective pressure, power to weight ratio and the volume power, are also acquired. Compared with three different types of conventional engines, the TRPE has a bigger utilization ratio of cylinder volume, a higher power to weight ratio and a more compact structure. This indicates that TRPE is superior to conventional engines. 相似文献
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重点阐述了济宁二号煤矿一采区泵房简易自动排水实践的过程。通过详细的计算和对现场实际数据的分析,选用砂泵与水位控制开关,实现了采区泵房无人职守自动排水。与其他自动排水泵房相比,该装置简单易行,资金投入少,维护方便,减少了人员配置,在同类泵房中具有较高的推广价值。 相似文献
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目的评估喹啉铜在枇杷中的残留消解、储藏稳定性和慢性膳食风险。方法实验样品用草酸溶液提取,亲水亲脂平衡(hydrophilic-lipophilic balance, HLB)固相萃取柱净化,超高效液相色谱检测,外标法定量,评估储藏稳定性和慢性膳食风险。结果喹啉铜在枇杷上的消解速率符合一级动力学方程,半衰期为3.4~4.6 d。枇杷样品在–18℃储藏150 d,喹啉酮的降解率小于30%。膳食风险评估结果表明,各年龄段人群喹啉铜的估算每日摄入量为0.0891~0.6945μg/kg bw/d,膳食摄入风险为0.45%~3.47%。结论喹啉铜在枇杷中消解较迅速;喹啉铜在枇杷样品中储藏稳定期至少为150d;对不同年龄阶段人群的长期慢性膳食暴露风险极低,均在可接受范围之内。 相似文献
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太行山高速四标段位于邯郸武安市冶陶镇,施工现场存在多处跨越既有线路施工部位,如青兰高速、G309国道、191乡道、村道等既有线路,其中G309国道作为一条交通主干道,车流量和人流量较大,因此,在T梁过跨施工时如何在不中断交通的情况下保障车辆及行人安全是施工中的管控要点,本文主要分析龙虎河大桥跨越G309国道时安全防护门洞的设计与施工思路以及施工前后的安全管控重点。 相似文献