A dual-band reconfigurable direct-conversion receiver RF front-end

6 dBm at 2.2 GHz, and a gain of 18.8 dB and IIP3 of 7.3 dBm at 4.5 GHz. The whole front-end consumes 12 mA current at 1.2 V voltage supply for the LNA and 2.1 mA current at 1.8 V for the mixer, with a die area of 1.2 × 1 mm2.     

Miscibility of poly (etherimide) and poly (butylene naphthalate) blends

Summary Differential scanning calorimeter (DSC), optical microscopy (OM) and scanning electron microscopy (SEM) were performed to characterize the miscibility of a blend system comprising poly (butylene naphthalate) (PBN) and poly (ether imide) (PEI). DSC scans showed there was only one single Tg for each blend and the glass transitions increase monotonously with the increase of PEI content. The glass transition temperatures of the blends fitted the Fox equation well implying that the blends exhibited fine segmental scale of mixing. No lower critical solution temperature (LCST) was observed by OM for the blends. SEM micrographs showed the fracture surface of quenched sample exhibited a homogeneous structure. No obvious IR peak shift of C=O absorption at 1780 cm⁻¹ was observed suggesting a relatively low level of specific interaction between two molecules. It was concluded that these blends were miscible with non-specific intermolecular interactions. Received: 5 January 2001/Accepted: 27 February 2001     

气体辅助注射保压过程的数值分析

基于气体辅助注射成型保压过程的工程认识，利用粘性，可压缩非牛顿流体基本方程，得到了气体辅助注射保压过程分析的控制方法，并采用有限元法／有限差分法实现了对保压过程的数值模拟，并对过实例说明了气体辅助注射的优越性。     

盘式蚊香喷药设备的研制

针对目前蚊香行业生产工艺现状，设计研制了一种喷药设备；阐述了本设备的工作原理，指出了本设备在设计、制作、选材等方面的优点，并与原工艺进行了分析比较；认为研制的新设备在提高驱蚊效果，减少厂家资金周围压力，提高成品合格率，降低生产成本等方面大大优于原工艺。     

Characterization and Properties of Recycled Polypropylene/Coconut Shell Powder Composites: Effect of Sodium Dodecyl Sulfate Modification

This research work focuses on the utilization of coconut shell powder (CSP) as filler in recycled polypropylene (rPP). Sodium Dedecyl Sulfate (SDS) was used as coupling agent in these composites. The effect of filler content and SDS on tensile properties, thermal properties, water absorption and morphology of rPP/CSP composites were investigated. In this study, modified rPP/CSP composites with SDS show significant increased tensile propertied, thermal stability, crystallinity and low water absorption compared unmodified rPP/CSP composites. Those improvements were contributed by the coupling effect of SDS.     

铝基刚挠结合板制作工艺探讨

金属铝基由于其良好的散热性能，广泛应用于LED方面；但随着PCB技术进一步向短、小、轻、薄的方向发展，其平面安装技术在安装空间方面受到了极大的限制，因此，如何实现金属基板三维折叠安装成为业界新的研究课题。对铝基＋软硬结合板的制作工艺进行了可行性探讨，通过铝基表面复合处理工艺＋纯胶预贴局部撕胶十二氧化碳激光切割技术有效实现了金属铝基与挠性电路的有机结合，满足了客户对金属基板实现三维安装的特种需求。     

导流板对Savonius型海流发电叶轮的影响分析

Savonius型叶轮是应用最广泛的海流发电叶轮之一,其成本低、自启动性较好,但是发电效率较低。为了提高Savonius叶轮的发电效率,提出了在Savonius叶片上增加3块导流板的新型垂直轴式叶轮的设计方案。为了探索导流板对叶轮的发电性能影响,利用商业计算流体力学(CFD)软件FLUENT分析了叶轮在不同旋转速度下的发电特性,采用滑移网格技术对叶轮进行了2D非定常数值流体计算,分析了在工作环境下叶轮的速度场、压力场的基本特点。计算结果表明,该叶轮在尖速比λ=0.9时获得最大平均功率系数0.481,其发电效率大约比Savonius叶轮高10%～20%左右。