Ar/N2气体比例对TaN/NbN纳米多层膜机械性能的影响

采用射频磁控溅射系统,以TaN和NbN作为体材料,制备了一系列TaN/NbN纳米多层膜.通过XRD,纳米力学测试系统分析了该体系合成中Ar/N2气体比例对多层膜结构与机械性能的影响.结果表明,纳米多层膜的硬度值普遍高于两种个体材料混合相的值;当FArFN2=10时TaN的(110)峰加强,TaN的晶体结构以六方结构为主,NbN的晶体结构以面心立方结构为主,此时,多层膜体系的硬度、弹性模量以及膜基结合性能均达到最佳效果(最大硬度为30 GPa),摩擦磨损实验表明,Ar/N2比为101的TaN/NbN多层膜较其他Ar/N2比的多层膜耐磨性更好,不易发生破损,适合实际应用.     

Investigation of ferroelectric properties on nanocrystalline barium titanate ceramics

Dense nanocrystalline BaTiO₃ (BT) ceramics with 50 nm average grain size obtained by spark plasma sintering were investigated. The dielectric data showed a ferropara phase transition with a maximum permittivity of 1,602 at 120°C and at 1 kHz. The polarization reversal characteristics were measured, and the typical piezoelectric hysteresis loop was recorded. The asymmetry of permanent polarization and coercive field in polarization-electric field curves were obtained and attributed to the existence of an internal electric field. The present results provide experimental evidence, indicating that if a critical grain size exists for ferroelectricity, then it is less than 50 nm for polycrystalline BT ceramics.     

基于短距离无线/有线通信的燃气监测报警系统

根据燃气泄漏多发区域对燃气浓度监测的需求,提出基于短距离无线/有线通信的燃气监测报警系统。系统选用通用的可燃气体传感器和温度传感器、8位单片机和433 MHz无线通信芯片为核心器件,完成无线/有线燃气监测报警终端的软硬件设计,设计完成了接收终端和上位机监控软件。燃气监测报警系统能对燃气浓度和环境温度远程实时地进行监测,具有动态显示、历史数据查询和二级报警等功能。     

β”-Al_2O_3辐射损伤的高分辨电镜研究

β″-Al_2O_3是重要的快离子导体,离子传导由结构中的钠氧层承担,每个β″-Al_2O_3晶胞中含三个尖晶石“基块”,相间三个钠氧传导层(见图1)。有人用高分辨电子显微镜曾观察到,β″-Al_2O_3在电子束作用下其钠氧传导层消失,从而导致相邻的两个尖晶石块直接相连。我们不仅从高分辨象,而且还从电子衍射的结果证实了这种二基块直接相连的现象,并进一步发现:β″-Al_2O_3在电子束作用下,还会产生超结构现象.我们的研究还指出,这类电子辐射损伤还与材料中某些缺陷有关.电子辐射产生大量缺陷,缺陷的产生反过来使辐射损伤进一步加快,在某些区域甚至出现无序化的倾向。     

低温共烧陶瓷发展进程及研究热点

低温共烧陶瓷(LTCC)是现代微电子封装中重要的研究分支,主要用于高速、高频系统。介绍了低温共烧陶瓷的发展历程及其中包含的若干重大研究热点,如铜布线工艺、收缩率匹配、LTCC散热等。     

Influence of Hydrogen on Dislocation Structure in a Duplex Stainless Steel

The dislocation structure of specimens of aduplex stainless steel with precharged hydrogen hasbeen investigated by transmission electronmicroscopy.The result showed the hydrogen acti-vated dislocation source on phase boundaries offerrite/austenite and makes certain dislocations inaustenite grains move.The dislocation appearancesin each phase in specimens uncharged withhydrogen have been given for comparison.     

DNA Synthesis during Endomitosis Is Stimulated by Insulin via the PI3K/Akt and TOR Signaling Pathways in the Silk Gland Cells of Bombyx mori

Silk gland cells undergo multiple endomitotic cell cycles during silkworm larval ontogeny. Our previous study demonstrated that feeding is required for continued endomitosis in the silk gland cells of silkworm larvae. Furthermore, the insulin signaling pathway is closely related to nutritional signals. To investigate whether the insulin signaling pathway is involved in endomitosis in silk gland cells, in this study, we initially analyzed the effects of bovine insulin on DNA synthesis in endomitotic silk gland cells using 5-bromo-2''-deoxyuridine (BrdU) labeling technology, and found that bovine insulin can stimulate DNA synthesis. Insulin signal transduction is mainly mediated via phosphoinositide 3-kinase (PI3K)/Akt, the target of rapamycin (TOR) and the extracellular signal-regulated kinase (ERK) pathways in vertebrates. We ascertained that these three pathways are involved in DNA synthesis in endomitotic silk gland cells using specific inhibitors against each pathway. Moreover, we investigated whether these three pathways are involved in insulin-stimulated DNA synthesis in endomitotic silk gland cells, and found that the PI3K/Akt and TOR pathways, but not the ERK pathway, are involved in this process. These results provide an important theoretical foundation for the further investigations of the mechanism underlying efficient endomitosis in silk gland cells.     

降低植物油抽提溶剂中芳烃含量的研究

采用新型的脱芳催化剂,对植物油抽提溶剂进行了加氢脱芳试验。结果表明,在温度130~140℃、压力0.15~0.25 MPa(表压)的温和工艺条件下,可将粗植物油抽提溶剂中的苯质量分数由(600~800)×10-6降到10×10-6以下,产品质量符合目前国内外市场上高标植物油抽提溶剂的要求。     

大规模风力发电并网对系统小干扰稳定性的影响

以西北电网酒泉风电系统为算例,分析了不同风电机组类型、不同风电容量、不同并网位置对电力系统小干扰稳定性的影响。仿真结果表明：相比于恒速风力机模型和直驱式同步发电机模型,风电场采用双馈异步发电机模型并网对系统小干扰稳定性的影响较好;随着双馈并网有功出力的增加,系统小干扰稳定性减弱;选择合适的风电场位置可以为系统提供较好的阻尼。     

海洋石油平台钢桩内水泥清理装置研究及试验

为解决弃置海洋石油平台导管架钢桩内有水泥灌注的问题,研究一种适用于水下作业的导管架钢桩内水泥清理装置。对比分析目前各种水泥破碎方法的优点、缺点及应用情况,结合水下作业环境,得出基于高压水射流原理的导管架钢桩内水泥清理方法可行。设计包括给水泵、高压水泵、合流块、液压动力单元、液压控制台、角度显示装置、供气动力单元和高压水喷头的海洋石油平台钢桩内水泥清理装置。结果表明：该装置可有效地解决海洋石油平台弃置过程中导管架钢桩内有水泥的工程问题。