The effect of the lower stress level on the cyclic creep behavior of an ods superalloy

Metallurgical and Materials Transactions A - Cyclic creep and stress rupture results are reported and discussed as a function of the lower applied load for INCONEL MA6000, which is a mechanically...     

Integration of high-speed optical taps with InP waveguides

Optical taps are key elements for optical signal processing. The authors demonstrate the high-speed operation of an InGaAs p-i-n photodetector on InP waveguides. For a 300- mu m-long tap that samples 19% of the light propagating in a 7- mu m-wide waveguide, the response time is 50 ps at a 1 V reverse bias. The taps require a simple epitaxial growth and can readily be integrated with electrooptic modulators and other optoelectronic devices for multigigahertz optical signal processing.<>     

Discontinuous Coarsening of Tetragonal Precipitates in Partially Stabilized Zirconia Induced by Diffusional Coherency Strain under Applied Stress

When partially stabilized zirconia with 6 mol% MgO and 4 mol% CaO is aged at 1450°C, intragranular precipitation occurs and concurrently the boundaries between the grains migrate, forming a Ca-enriched precipitate-free cubic phase and large tetragonal precipitates behind them. At these compositions and temperature the boundary migration is rapid and shows the characteristics of a discontinuous coarsening. A uniaxial compressive stress applied to this specimen during the aging treatment increases or decreases the migration rate of the boundaries parallel or perpendicular to the stress axis, respectively, in agreement with the prediction that a compressive coherency strain due to the diffusion of Ca atoms is produced at the surface of the retreating grains and drives the migration. The diffusional coherency strain energy is thus expected to be the dominant driving force for the discontinuous coarsening in this solid.     

Bit error rate performance for optical fiber systems with modalnoise

A gamma distribution is used to model the received optical power fluctuation in a digital fiber-optic system affected by modal noise. New recursive formulas for the moments of the receiver output current are obtained which can be used in the Gauss quadrature rule (GQR) approximation of the error probability integral. Error rates have been calculated for varying degrees of modal noise disturbance     

Coherent optical communication with injection-locked high-power semiconductor laser array

Heterodyne FSK communication at 110 Mbit/s is demonstrated with an injection-locked high-power 20-stripe semiconductor laser array. It is shown that a high-power (>300 mW) coherent optical transmitter can be constructed without penalty in bit error rate performance.<>     

SOI数模混合集成电路的串扰特性分析

采用二维TMA Medici模拟软件对SOI结构的串扰特性进行了分析.模拟发现随着频率的增加,SOI的埋氧化物对串扰噪声几乎不起隔离作用,同时,连接SOI结构的背衬底可以在很大程度上减小串扰的影响.还对减少串扰的沟槽隔离工艺、保护环及差分结构的有效性进行了比较分析,对一些外部寄生参数对串扰的影响也进行了研究.并给出了SOI结构厚膜和薄膜结构体掺杂浓度对噪声耦合的影响,所得到的结果对设计低噪声耦合的SOI数模混合集成电路具有指导性的作用.     

Analysis of molecular orientation and internal stresses in extruded plastic sheets

The development of molecular orientation and internal stresses in extruded sheet made of polypropylene was analyzed, and their correlations to operating conditions such as draw ratio, cooling rate, die temperature, melt temperature, and die gap opening were studied. Measurements of attenuated-total-reflectance infrared dichroic ratio for the surface molecular orientation, birefringence for the orientation stress distribution in the thickness direction, and free shrinkage ratio for the overall frozen-in stresses were carried out to determine the amount of orientation stresses in the extruded samples. As expected, the overall orientation stress depends strongly on draw ratio, while higher melt temperature reduces the overall orientation. It was found that faster cooling rates and lower die temperatures cause surface orientation stresses to increase as the core orientation stresses remain almost unchanged.     

A stacked CMOS technology on SOI substrate

A stacked CMOS technology fabricated on semiconductor-on-insulator (SOI) wafers with the p-MOSFET on the SOI film and the n-MOSFET on the bulk substrate is demonstrated. The technology provides a number of advantages, including: 1) single crystal multi-layer of active devices; 2) self-aligned double-gate p-MOSFET with thick source/drain and thin channel regions; 3) self-aligned channel region of n-MOSFET to p-MOSFET stacked perfectly on top of each other; 4) significant area saving; and 5) reduced interconnect distance and loading. Experimental results show that the fabricated double-gate p-MOSFET has a nearly ideal subthreshold swing and almost the same current drive as the n-MOSFET with the same lateral width, resulting in a highly compact and completely overlap stacked CMOS inverter.     

Cu/Al固液连接界面组织演化的定量分析

采用固-液法快冷成型制备了Cu/Al整体材料。利用SEM,EDS,XRD等分析了Cu/Al界面的微观结构和相组成,基于扩散方程并结合相图定量分析了Cu/Al界面组织演化过程。结果表明：从Cu侧至Al侧,界面依次形成了区域Ⅰ(AlCu+Al2Cu)混合组织,过共晶组织 [Al2Cu+(Al2Cu+α-Al)]的区域Ⅱ和亚共晶组织 [α-Al+(Al2Cu+α-Al)]的区域Ⅲ;随着界面Cu浓度的变化,Al2Cu相具有不同形貌;且各个区域厚度同理论值基本一致。     

Impedance spectroscopy of polymer electrolytes based on epoxidized natural rubber with 50 mol% epoxide content

Polymer electrolytes of epoxidized natural rubber with 50 mol% epoxide content (ENR‐50) and lithium perchlorate (LiClO₄) were studied with respect to variation of thermal and electric properties with salt content. Below salt content of 5% and above 12%, glass transition temperature stays constant. A steep increase is observed in between. Frequency dependence of impedance was studied over a wide range of salt concentration. Complex impedance plots exhibit one semicircle. Location of semicircles above 12% clearly points towards phase heterogeneity. Analysis of resistivity leads to the result that one phase's resistivity corresponds to salt content of 12%, whereas the second phase exceeds this resistivity by one order of magnitude. Imaginary part of impedance supports this behavior with respect to resistivity. Polarization relaxation time, however, does not change with salt content. It demonstrates that the phase with the excess resistivity does not contribute to polarization relaxation. Therefore, universal dielectric behavior can be observed also in the heterogeneous system. POLYM. ENG. SCI., 55:2250–2255, 2015. © 2015 Society of Plastics Engineers