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以 MT9 M034作为光电成像元件,CYUSB3014作为主控芯片,通过 GPIF II接口采集 CMOS图像传感器的数据,并为每一帧数据添加 UVC视频数据标头,将其转换为符合 UVC协议标准的视频数据,最后通过 USB3.0接口以乒乓DMA的方式将其传送至PC,实现了免驱动、高速率、高分辨率的UVC视频设备。实验结果表明,该系统运行稳定,传输速率高,更换CMOS图像传感器可以制成不同规格的 UVC视频设备,具有良好的推广价值。 相似文献
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对快淬磁粉进行热压/热流变处理已成为制备高性能各向异性NdFeB磁体的一种重要方法,快淬粉的成分和结构极大地影响了磁体的热流变能力和磁性能。研究了辊速和喷射压力,对快淬磁粉结构和最终热流变磁体磁性的影响。提高辊速可以细化晶粒和增加快淬磁粉中的非晶含量,但非晶含量较高会不利于磁体热流变过程的晶粒取向和织构形成;而辊速较低会使快淬磁粉的晶粒尺寸较为粗大,降低其热流变能力和织构形成能力,最终降低热流变磁体的剩磁和最大磁能积。适合进行热流变处理的快淬带晶粒尺寸为25~40nm。减小喷射压力也可以细化晶粒,但不影响快淬磁粉的非晶含量。当喷射压力0.07 MPa时,快淬粉的XRD谱出现新的衍射峰,可能为亚稳相,其含量随喷射压力的减小而增加。新相的出现和含量的增加使得热流变磁体的剩磁、矫顽力和最大磁能积都降低。获得的最佳快淬工艺为辊速25m/s,喷射压力为0.07MPa,该条件下制备的热流变磁体磁性能为Br=1.29T,(BH)m=298.5kJ/m3,Hcj=920.17kA/m。 相似文献
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该文描述了一种工作频率在S波段的低损耗极窄带声表面横波谐振滤波器,解决了整机系统在高频率S波段载波近端的杂波抑制。采用一阶温度系数为0的石英基片及比瑞利型声表面波波速高1.6倍的声表面横波,制作出3dB带宽大于1‰的低损耗窄带谐振滤波器,其工作频率达2.4GHz,损耗为5.77dB,3dB带宽为3.0 MHz,在50Ω测试系统中测试,偏离中心频率±7 MHz的阻带抑制为25dB;在-40~+85℃内,频率漂移仅为705kHz。 相似文献
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Melt-spun ribbons which are the important raw material for hot-deformed magnets can be prepared by single-roller melt-spinning. In order to prepare well-structured ribbons, the model of temperature field for single-roller melt-spinning process was constructed in this work. The heat conduction in this process was simplified as one dimensional heat conduction problem. It was shown by modeling that, the temperature field in the melt-spinning before solidification in this model could be described as this equation T(x,t)=Tmoexp[–k(x–x0)–k2αt]+T0. The temperature T(x,t) of the alloy melts decreased with increased position x and cooling time t exponentially from the wheel-free surface to the wheel-side surface. The constant k determined the decrease speed of alloy temperature T(x,t), which was proportional to the interfacial heat transfer coefficient h and the interfacial area of heat conduction A0, but inversely proportional to the thermal conductivity K. x0 was the thickness of the alloy melt. With increased x0, the temperature difference between wheel-free surface and the wheel-side surface became larger, which would lead to larger difference in grain size. In experiments, the influence of melt-spinning process parameters on the temperature field model was discussed, such as cooling roller materials, wheel speed, and so on. Melt-spun ribbons prepared by single-roller melt spinning at different wheel speed were investigated and magnetic properties of die-upset magnets from melt-spun ribbons on different cooling roller were analyzed. The variation of grain size in the depth direction consisted with temperature field model. This model provided directions for the preparation of melt-spun ribbons with uniformly distributed fine grains, which were very necessary for producing hot-deformed magnets with high magnetic performance. 相似文献
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目的:针对子宫颈扩张球囊(COOK球囊)联合缩宫素在足月妊娠期高血压和轻度子痫前期患者引产的临床效果进行切实有效的分析和研究。方法:有针对性的选取我们医院在2017年10月到2018年10月这个时间段内所接收的80例足月妊娠期高血压和轻度子痫前期患者分娩患者作为本次研究的研究对象,针对所有研究对象随机分成对照组和观察组,两组各有40例患者,其中针对对照组患者所采取的是直接缩宫素引产,而针对观察组患者所采取的是COOK球囊联合缩宫素引产,针对两个组别患者所呈现出的产程进展、分娩结果、血压水平及重度子痫前期及新生儿窒息风险等相关情况进行有针对性的分析和对比。结果:经过相对应的方法实施之后,可以很明显的看出,在阴道分娩率方面,观察组患者要比对照组有十分明显的提升,而诱发临产时间、第一产程时间、重度子痫前期发生率等相关方面要比对照组患者有十分明显的降低,两者比较差异明显有统计学意义,(P0. 05)。在胎盘早剥、产后出血、产后感染以及新生儿窒息的发生率等相关方面,两者比较都没有明显的差异,无统计学意义,(P0. 05)。结论:针对具体的临床实践来看,对于足月妊娠期高血压和轻度子痫前期孕妇进行切实有效的子宫颈扩张球囊联合缩宫素引产所呈现的临床成效十分明显,可以在很大程度上有效促进产妇的宫颈尽快成熟,这种方法所呈现出的引产效果要比直接使用缩宫素进行引产有十分明显的提升,该方法有比较明显的临床应用价值,值得临床应用和推广。 相似文献