基于新型控制器LM2588系列的多路供电电源设计

传统回扫式电路由于连续型和断续性控制特点不同,存在系统稳定性设计较难,升压型电路会产生较大噪声干扰和输出纹波电压。本文以最新的LM2588系列控制器为基础,旨在实现一种能够满足多路供电电压输出而无须进行复杂设计的小型、低成本、高集成度的电源解决方案。     

Thin-film reactions during diffusion soldering of Cu/Ti/Si and Au/Cu/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> with Sn interlayers

The multilayer thin-film systems of Cu/Ti/Si and Au/Cu/Al₂O₃ were diffusion-soldered at temperatures between 250°C and 400°C by inserting a Sn thin-film interlayer. Experimental results showed that a double layer of intermetallic compounds (IMCs) η-(Cu_0.99Au_0.01)₆Sn₅/δ-(Au_0.87Cu_0.13)Sn was formed at the interface. Kinetics analyses revealed that the growth of intermetallics was diffusion-controlled. The activation energies as calculated from Arrhenius plots of the growth rate constants for (Cu_0.99Au_0.01)₆Sn₅ and (Au_0.87Cu_0.13)Sn are 16.9 kJ/mol and 53.7 kJ/mol, respectively. Finally, a satisfactory tensile strength of 132 kg/cm² could be attained under the bonding condition of 300°C for 20 min.     

提高粒子碰撞噪声检测试验可靠性的途径

文章从粒子碰撞噪声检测(PIND)试验的原理入手，着重阐述了影构PIND试验的因素和提高PIND试验可靠性的途径。通过对PIND试验的波形分析来提高PIND试验的可靠性，使试验数据更客观、准确，以此来保证和提高产品质量。     

小波变换在微光图像消噪中的应用算法研究

根据小波变换用于图像消噪的原理,结合微光图像噪声的闪烁颗粒性特点,对小波变换用于微光图像消噪时的小波基及小波分解层次的选取进行了分析,得出采用Haar小波进行一层分解即可满足微光图像消噪要求的结论。为了选取小波消噪的系数阈值,通过对三幅微光图像小波系数的直方图分析,设计了阈值选取算法,并针对微光图像,得出了消噪的经验阈值。经过仿真实验及算法复杂度的时间分析,在实时性和微光图像消噪效果之间取得了平衡。     

一种使用开路并联线的改进型螺旋微带谐振单元

提出了一种改进型螺旋微带谐振单元(SCMRC)的结构.该改进型螺旋微带谐振单元具有微带并联开路线,在低频通带内通过设计达到50Ω的端口阻抗.同时,并联的微带开路线在SCMRC结构的禁带中谐振,来实现更强的慢波效应和更宽的禁带.实际设计、制作和测试了该改进型螺旋微带谐振单元,该滤波器在低频通带内具有低插入损耗、改善的回波损耗,以及在较小面积下的宽禁带.     

Designing a binary controller to enhance end-to-end congestion control

Active queue management (AQM) is proposed to enhance end-to-end congestion control through purposefully dropping packets in the intermediate nodes. In this letter, a novel packet dropping mechanism is developed through designing a binary controller applying the robust control theory. The new mechanism can simplify the manipulation on the AQM router so as to be helpful for implementing the high performance router. The numerical simulation results show that the binary controller can satisfy with the technical requirements for AQM     

车载CAN总线在环测试技术研究

针对目前对CAN总线网络测试手段仅仅采用专用总线接口芯片采用监听方式获知总线完好的数据帧,车载总线因畸变、干扰等造成的错误、异常数据帧都被专用总线协议芯片过滤掉,没办法对总线物理层的传输波形进行测试,总线上出现故障节点无法定位故障节点等问题,这里提出了车载CAN总线在环测试技术,设计了在环测试实验方案,并利用测试节点仿真设备验证了该技术在故障定位方面的可行性。     

聚乙烯醇凝胶堵漏剂的室内研究

为解决地质钻孔钻井液漏失的问题,研制了一种新型堵漏剂——聚乙烯醇凝胶堵漏剂,该堵漏剂由聚乙烯醇、硼砂、二丁酯、羧甲基纤维素钠等化学交联反应而成。根据地质钻探钻孔堵漏材料性能的要求,对该堵漏剂进行了成胶时间、成胶黏度、溶胀性、抗稀释性、抗矿化物污染、堵漏等实验。结果表明:(1)当聚乙烯醇为3%、硼砂为0.8%、二丁酯为0.3%、羧甲基纤维素钠为0.3%、交联温度为35℃、p H值为10时,制备的聚乙烯醇凝胶堵漏剂性能为最好,成胶黏度达358 600 m Pa·s,成胶时间为18min;(2)成胶时间在0.1~1.0 h范围内可调,对不同大小通道适宜性好;(3)单独的凝胶堵漏剂最大承压能力达到6.0 MPa,加入1%木屑后最大承压能力提高到7.0 MPa,具有很好的堵漏效果。结论认为,所研制的聚乙烯醇凝胶堵漏剂具有较强的溶胀度、抗稀释、抗矿化物污染和堵漏能力,并且制备方便、价格低廉,可应用于裂缝、溶洞、孔隙及含有动水的复杂漏失地层。     

基于地应力的库车前陆盆地储层有效性测井评价

库车前陆盆地高陡构造的白垩系致密砂岩储层处于异常高压和强地应力状态,常规测井解释技术评价该类储层有效性的结论常与试油结果相矛盾,影响了该类油气田的高效开发。针对该类低孔隙度裂缝性高压储层,从岩石力学角度出发,准确计算高陡构造地层的地应力,研究其与储层有效性的对应关系,提取有效应力比和走向应力差等参数,建立储层有效性评价标准并识别优质储层,形成了一套基于地应力的高陡构造储层有效性的测井评价方法,为研究区深层裂缝性砂岩储层有效性的测井评价提供了全新的途径,也为试油和压裂酸化等选层提供了可靠的岩石力学依据。将该方法用于新井储层有效性评价中,效果良好。     

Analysis of a liquid crystal Fabry-Perot etalon filter: a novel model

The authors propose a novel analysis method to investigate the characteristics of an electrically tunable liquid-crystal Fabry-Perot interferometer (LC-FPI). Based on the solution of deformation analysis of the liquid crystal in an electric field and the assumption of small refractive index variation in the Fabry-Perot cavity, the voltage-dependent equivalent refractive index of the cavity has been derived. Tuning behaviors of the LC-FPI filter were simulated by means of the dependence. The calculated result and the experimental measured data agree well with each other.