Robustness comparison of DG FinFETs with symmetric, asymmetric, tied and independent gate options with circuit co-design for ultra low power subthreshold logic

Double gate FinFETs are shown to be better candidates for subthreshold logic design than equivalent bulk devices. However it is not so clear which configuration of DG FinFETs will be more optimal for subthreshold logic. In this paper, we compare the different device and circuit level performance metrics of DG FinFETs with symmetric, asymmetric, tied and independent gate options for subthreshold logic. We observe that energy delay product (EDP) shows a better subthreshold performance metric than power delay product (PDP) and it is observed that the tied gate symmetric option has ≈78% lower EDP value than that of independent gate option for subthreshold logic. The asymmetry in back gate oxide thickness adds to further reduction in EDP for tied gate and has no significant effect on independent gate option. The robustness (measured in terms of % variation in device/circuit performance metrics for a ±10% variation in design parameters) of DG FinFETs with various options has also been investigated in presence of different design parameter variations such as silicon body thickness, channel length, threshold voltage, supply voltage and temperature, etc. Independent gate option has been seen to be more robust (≈40% less) than that of tied gate option for subthreshold logic. Comparison of logic families for subthreshold regime with DG FinFET options shows that for tied gate option, sub-CMOS, sub-Domino and sub-DCVSL have almost similar and better energy consumption and robustness characteristics with respect to PVT variations than other families.     

超细仿麂皮染整工艺

针对目前普遍关注的海岛型超细纤维的染整加工工艺，结合日本、韩国以及实验室的研究成果，对该类纤维的染整加工作简要描述，并对其使用的染料及牢度进行测试。结果表明，使用ANOCRON超细专用染料可提高各项牢度。     

满山香子多糖的膜分离研究

研究以满山香子为原料提取多糖的过程及工艺。利用超滤膜分离装置进行满山香子多糖的分离,对影响超滤的工艺条件,如压力、温度、时间进行考察,确定最佳的提取条件:满山香子∶水=1∶20,提取温度80℃,提取时间2h。提取物的多糖含量5.65%,超滤后的提取物中多糖含量达到80.29%,提取物得率为1.19%。     

超高效液相色谱串联质谱法测定乳制品中 10种青霉素类抗生素残留

目的建立同时测定乳制品中10种青霉素类抗生素残留的超高效液相色谱-串联质谱分析方法。方法样品经乙腈提取后,乙腈饱和正己烷除去脂肪,经0.22μm微孔滤膜过滤,用乙腈-水(含0.1%甲酸5mmol/L乙酸铵)为流动相,C18柱分离,20 min内梯度洗脱分离10种青霉素;电喷雾正离子模式电离(ESI+),多反应监测模式检测(MRM),外标法定量。结果在0.1~20μg/L浓度范围内,10种青霉素类药物在各种乳制品基质中均有良好的线性关系,线性相关系数均0.999;液体乳最低检测限为0.2μg/kg~1.0μg/kg,乳粉的最低检测限1.0μg/kg~5.0μg/kg;方法回收率在70.2%~108.2%,相对标准差为15%。结论该方法测定乳制品中10种青霉素药物的残留量简便、快速、准确,可以满足对青霉素类抗生素的监测要求。     

西甜瓜中农药多残留方法研究

本研究采用了超高效液相色谱-串联质谱联用（UPLC-MS/MS）技术,建立了同时检测西甜瓜中14种农药的多残留检测方法。样品经乙腈提取,氨基固相萃取柱净化,Waters HSST3超高效液相色谱柱分离,进入电喷雾串联四级杆质谱进行检测,采用多反应监测（MRM）分析,对液质分离条件和样品前处理条件进行了优化。结果表明14种农药在10-200μg/L范围内线性良好（r≥0.9961）。在0.01、0.05、0.10mg/kg浓度范围内,平均加标回收率在80.1%-112.2%之间;相对标准偏差RSD（%）≤9.2%。该方法的最低检出限范围为1.92×10-4-2.38×10-3mg/kg。     

Ultra2 SCSI PCB设计中的阻抗匹配问题

在高速逻辑设计中,需要考虑避免出现振铃、串扰等传输线现象.就此,详细讨论了在Ultra2 SCSI单端和差分模式兼容下PCB的两种输出阻抗及其与连接电缆的阻抗匹配问题的解决方法,简单介绍了在这样的高速逻辑系统中,PCB设计通常要考虑的一些其它问题.     

Detection of interdependent primary systems using wideband cognitive radios

Cognitive radios (CRs) may be sharing multiple frequency bands with primary systems if the CR is a wideband or an ultra wideband (UWB) system. In that case, the CR should ensure all the coexisting primary systems in these bands are detected before it can start data transmission. In this work, we study the primary system detection performance of a wideband CR assuming that there are multiple coexisting primary systems and that these primary systems may be jointly active. Accordingly, we consider the implementation of energy detection scheme in multiple bands followed by two detection methods: (i) a maximum-a-posteriori (MAP) based detection (i.e., joint detection) that takes into account the statistics of simultaneously operating systems in independent bands and (ii) a Neyman–Pearson (NP) test based detection that optimizes the threshold values independently in each band (i.e., independent detection). For a simpler implementation of the independent detection, we show that the threshold values obtained from joint detection can be used in order to achieve the optimum NP test based independent detection results. In addition to quantifying the gain of joint detection over independent detection in terms of probabilities of false alarm and detection for practical scenarios, we also present the operation capability of CRs in terms of the fractions of time the CR can access the channel without interfering with the primary systems. The results are important for the practical implementation of multiband detection when the primary systems are known to be interdependent.     

A single-magnet nonlinear piezoelectric converter for enhanced energy harvesting from random vibrations

Power harvesters from mechanical vibrations are commonly linear mechanical resonators that are most effective when excited at resonance. Differently, under wideband vibrations, linear converters are suboptimal. A nonlinear converter is here proposed that implements nonlinearity and bistability by employing a single external magnet, in order to improve conversion effectiveness while simplifying device fabrication. The converter is composed of a piezoelectric bimorph on a ferromagnetic cantilever. The fabrication technology is based on the screen printing of a PZT low-curing-temperature paste on harmonic steel substrate. The ferromagnetic cantilever converter, under proper coupling with the external magnet, bounces between two stable states when excited by random vibrations and generates an electric output via the piezoelectric effect. According to theoretical predictions, when bistable behaviour is present, experimental results demonstrate an improvement of about 400% of the rms voltage generated by the converter with respect to the linear case.     

Flexural performance of fiber-reinforced ultra lightweight cement composites with low fiber content

This paper presents an experimental study on flexural performance of ultra lightweight cement composites (ULCC) with 0.5 vol% fibers. Low density of the ULCC is achieved by using cenospheres from coal-fired power plants as micro aggregates. Effects of shrinkage reducing admixture (SRA) and fiber types on compressive strength and flexural performance of the ULCC are investigated. ULCC with density of 1474 kg/m³, compressive strengths of 68.2 MPa, flexural strength of 8 MPa, and deflection hardening behavior can be produced. Such good performance could be attributed primarily to the SRA which reduced entrapped air in paste matrix and densified fiber–matrix interface. The improvement on the flexural performance of the ULCC depends on fibers used and bond between fibers and matrix. Improvement of the flexural performance of the steel fiber (coated with brass) reinforced ULCC due to the densification effect by SRA was more significant than that of the PE fiber reinforced ULCC.     

Design of wideband hybrid silicon carbide single-stage power amplifier

RF wideband power amplifiers are desirable as they will reduce equipment, power consumption and operating cost for the RF communication infrastructure. For decades, the realization of single-stage broadband power amplifier has posed a significant challenge due to the electrical and thermal limitations of GaAs transistor technology. Silicon carbide (SiC) MESFET technology is a strong contender for such applications due to its superior properties. In particular, its high impedance reduces mismatch commonly encountered in such power amplifier.In this work, design of wideband hybrid single-stage power amplifier using a commercial 4H-SiC MESFET CRF24010 from Cree Inc is presented. The amplifier has been designed and fabricated for operating frequencies 650-1800 MHz, which is equivalent to more than 90% bandwidth, compared to only 3-4% bandwidth achievable using GaAs technology.