Exchange-Coupled IrMn/CoFe Mulitlayers for RF-Integrated Inductors

The high-frequency characteristics of the RF integrated inductors with antiferromagnetic/ferromagnetic (AF/F) multilayers (MLs) are studied. Each AF layer is 8-nm IrMn and F is Co₅₀Fe₅₀ with a 200-nm splitting into N = 1 to 5 repeats of MLs. This exchange coupled {IrMn/CoFe(d nm)}_N MLs are deposited on top of the two-port inductors with five-turn square spiral coils, a dimension of 100 mum times 100 mum and line/space of 5 mum/2 mum. The inductor surface and magnetic layer is separated by 1-mum-thick SiO₂. The enhancement of inductance (DeltaL) is 20% compared to an air-core of the same coil size. The resonance peak gradually shifted to a higher frequency with increasing N, and reached at a maximum of 4.3 GHz when N = 5. This is in good agreement with our magnetic data which revealed that the anisotropy field (H_k) and ferromagnetic resonance frequency (f_FMR) of {IrMn/CoFe(d nm)}_N MLs are increased with increasing N. The quality factor, Q is improved by 6.8% at 1.5 GHz for the {IrMn/CoFe(40 nm)}_N=5 integrated inductors compared to air-core inductors.     

Successive oxide breakdown statistics: correlation effects, reliability methodologies, and their limits

This paper deals with the statistics of successive oxide breakdown (BD) events in MOS devices. Correlation effects between these successive events are experimentally related to the statistics of BD current jumps, thus suggesting that they are related to lateral propagation of the BD path. The application of the successive BD theory to chip reliability assessment is discussed. Several failure criteria and the related reliability methodologies are considered and some of their limits are established.     

Accounting for constraint effects in fracture mechanics analysis of floating production, storage and off-loading vessels and ships

Research has been performed to study the effect of constraint dependent fracture toughness of parent metal and HAZ for steels applied for fabrication of oil and gas floating production, storage and off-loading (FPSO) vessels and ships. A test method was employed to study the HAZ crack tip opening displacement (CTOD) fracture toughness at various levels of constraint avoiding excessive scatter usually associated with conventional HAZ CTOD testing, which may obscure effects of constraint.The objective of the research was to determine the material dependent constraint parameters in Ainsworth and O'Dowd's constraint modified fracture assessment approach and to develop a method based on information from the literature pertaining to the structural constraint in plates with semi-elliptical surface cracks. Results due to Wang and Parks and Nakamura and Parks computed using line-spring and FE analyses were used to establish polynomial expressions for the structural constraint in tension and bending applicable to fracture assessment of shallow fatigue cracks initiated at weld toes in floating offshore structures such as FPSOs.The results of the analyses clearly show that fracture assessment of semi-elliptical surface cracks in tension would be overly conservative if constraint effects are not accounted for in the Option 1 or Option 2 fracture assessment curves or in fracture toughness. It was also found from the tests conducted on specially prepared wide-plate test specimens, that the constraint modified Option 1 curve was conservative for fracture assessment of semi-elliptical surface cracks located in the HAZ of a 500 MPa minimum specified yield strength quenched and tempered steel for offshore application.     

杂质非完全离化对SiC n-MOSFET电特性的影响

文章研究了SiC中杂质非完全离化对器件性能的影响.通过考虑场致离化效应,分析了空间电荷区电荷密度与表面势的关系,得出在SiC MOSFET反型条件下,可近似认为杂质完全离化.在此基础上,模拟了4H-SiC MOSFET的漏电流-栅压曲线和迁移率-栅压曲线.模拟结果与实验数据非常吻合.     

A theory of rectangular dual graphs

Arectangular graph is a plane graph where all regions are four-sided and all edges are oriented in either the vertical or the horizontal direction. In addition the graph enclosure must also be rectangular. Given a plane graph representing a desired component connectivity, itsrectangular dual can be used to build afloorplan. This indicates that a system implementation can allocate rectangular floorplan regions to components that can be pairwise connected through common borders. This paper proves that constructing a rectangular dual graph is equivalent to a matching problem in a bipartite graph derived from the given plane graph. A simple existence theorem in terms of the graph structure is obtained as a corollary.     

A theory of rectangular dual graphs

Arectangular graph is a plane graph where all regions are four-sided and all edges are oriented in either the vertical or the horizontal direction. In addition the graph enclosure must also be rectangular. Given a plane graph representing a desired component connectivity, itsrectangular dual can be used to build afloorplan. This indicates that a system implementation can allocate rectangular floorplan regions to components that can be pairwise connected through common borders.This paper proves that constructing a rectangular dual graph is equivalent to a matching problem in a bipartite graph derived from the given plane graph. A simple existence theorem in terms of the graph structure is obtained as a corollary.This work was supported by the National Science Council, Taiwan, Republic of China, under Contract NSC 78-0404-E006-14.     

带约束的复FIR数字滤波器Chebyshev设计算法

本文主要讨论了复FIR数字滤波器的频域不等式约束Chebyshev设计问题.作者首先把文献[1]中的复交错点组定理扩展到有不等式约束的情况,之后根据扩展定理中对最优解特性的描述,并结合复Remez算法[1]及赖晓平的迭代Remez算法[2][3],提出了一种有效的算法来解决频域带不等式约束的复FIR数字滤波器的Chebyshev设计问题.如果问题的解存在,则算法能保证收敛到最优解.作者用MATLAB语言对上述算法进行了实现并做了仿真分析.     

A 1-V 86-mW-RX 53-mW-TX Single-Chip CMOS Transceiver for WLAN IEEE 802.11a

A 1-V WLAN IEEE 802.11a CMOS transceiver integrates all building blocks on a single chip including a transformer-feedback VCO and a stacked divider for the frequency synthesizer and 8-bit IQ ADCs and 8-bit IQ DACs. Fabricated in a 0.18-mum CMOS process and operated at a single 1-V supply, the receiver and the transmitter consume 85.7 mW and 53.2 mW, including the frequency synthesizer, respectively. The total chip area with pads is 12.5 mm².     

Encapsulation of quantum dots and carbon nanotubes with polypyrrole in a syringe needle for automated molecularly imprinted solid phase pre-concentration of ochratoxin A in red wine analysis

Nanometer-sized semiconductor quantum dots (QDs with CdSe core and ZnS shell) and carbon nanotubes (CNTs with multi-walls) were encapsulated inside a stainless steel syringe needle by electrodeposition of polypyrrole (PPy). By cross-linking the PPy with ethylene glycol dimethacrylate (EGDMA) in the presence of ochratoxin A (OTA) as a template, molecularly imprinted polypyrrole (MIPPy) was formed on the nano-hybrid structure at an increased specific surface area. The MIPPy/CNTs/QDs-modified needle was readily adapted in an autosampler for micro-solid phase preconcentration (μSPP) of OTA from a red wine sample. After pulsed elution (PE) with 2% triethylamine (TEA), the OTA was determined by high performance liquid chromatography (HPLC) with fluorescence detection (FD). In comparison with MIPPy/CNTs, this new nano-hybrid structure of MIPPy/CNTs/QDs significantly improved the % recovery of OTA. The method, MIPPy/CNTs/QDs-μSPP-HPLC-FD, demonstrated that the MIPPy was truly a molecularly imprinted polymer (MIP) with specific recognition for OTA. All red wine matrix components could be differentially washed out, prior to accurate determination of the strongly bound OTA.     

A Coaxial Bragg Reflector for Cyclotron Autoresonance Maser Oscillators

A coaxial Bragg reflector is suggested for the application in the cyclotron autoresonance masers (CARMs), where both the outer wall and inner rod are corrugated with weak axisymmetric-sinusoidal-ripple, and a concept design is presented. It is found that, compared to the cylindrical Bragg reflector, the coaxial Bragg reflector has larger dimensional size, narrower bandwidth, and larger eigenvalue intervals. These peculiarities are favorable to the mode selectivity, the ability of dissipating the ohmic heat on the wall, the oscillating startup of the operating mode, and machining manufacture, and therefore, this new kind of Bragg reflector can be developed into a coaxial resonator for the high-power CARMs