基于谐振式反射器的脑活动探测天线设计

设计了一款用于脑活动探测的超宽带定向天线。该天线采用了平面菱形单极天线的宽频带特性,通过缺陷地结构实现小型化。为了增强天线的定向辐射能力,设计了一种花瓣形谐振式反射器,在较宽频带内产生同相反射,并可减少剖面高度至0.1λ0。该天线整体结构具有尺寸小、重量轻的特点。对天线结构进行仿真优化并加工实测,测试结果与仿真的一致性表明了该天线具有超宽带的特点,实测阻抗带宽为0.91~2.42 GHz(91%),且远场方向图表明了天线具有良好的定向性能,因而该天线可以应用于人脑活动探测等领域。     

敏感数据全生命周期安全防护方案探讨

数据成为国家和企业的重要战略资源,与企业运营、个人用户利益息息相关,为了实现数据安全保护,需要从数据的全生命周期入手,构建完善的数据安全防护体系。在数据安全建设过程中,既要包括权限管控、日志审计、数据脱敏等基础安全防护能力,也要探索机器学习、实时处理、人工智能等新技术在安全中的应用。     

Grobner bases, abstract tubes, and inclusion-exclusion reliabilitybounds

There is a close mathematical relationship between integer grids of a particular echelon form and coherent systems in reliability in the case of states coded as integer grid points. This paper shows that such an integer representation is the link between abstract tube theory, which gives improved inclusion-exclusion bounds, and an algebraic method, Grobner bases, based on the polynomial ideal of the failure event     

A 0.8-V 128-kb four-way set-associative two-level CMOS cache memory using two-stage wordline/bitline-oriented tag-compare (WLOTC/BLOTC) scheme

This paper reports a 0.8-V 128-kb four-way set-associative two-level CMOS cache memory using a novel two-stage wordline/bitline-oriented tag-compare (WLOTC/BLOTC) and sense wordline/bitline (SWL/SBL) tag-sense amplifiers with an eight-transistor (8-T) tag cell in Level 2 (L2) and a 10-T shrunk logic swing (SLS) memory cell. with the ground/floating (G/F) data sense amplifier in Level 1 (L1) for high-speed operation for low-voltage low-power VLSI system applications. Owing to the reduced loading at the SWL in the new 11-T tag cell using the WLOTC scheme, the 10-T SLS memory cell with G/F sense amplifier in L1, and the split comparison of the index signal in the 8-T tag cells with SWL/SBL tag sense amplifiers in L2, this 0.8-V cache memory implemented in a 1.8-V 0.18-/spl mu/m CMOS technology has a measured L1/L2 hit time of 11.6/20.5 ns at the average dissipation of 0.77 mW at 50 MHz.     

Outage probability and spectrum efficiency of cellular mobile radio systems with smart antennas

Relying on the distribution of noncentral multivariate F variates, we investigate the outage probability and spectrum efficiency performance of cellular systems with smart antennas. We consider interference-limited systems in which the number of interferers exceeds or is equal to the number of antenna elements, and we present closed-form expressions when the desired signal is subject to Rician-type fading and interfering signals exhibit Rayleigh-, or, more general Nakagami-type fading. When applicable, these new expressions are compared to those previously reported in the literature dealing with the performance of cellular systems without smart antenna capabilities and the performance of cellular systems with optimum combining when both the desired and interfering signals are subject to Rayleigh-type fading. Corresponding numerical results and plots are also provided and discussed.     

A high precision global prediction approach based on local prediction approaches

Traditional model-free prediction approaches, such as neural networks or fuzzy models use all training data without preference in building their prediction models. Alternately, one may make predictions based only on a set of the most recent data without using other data. Usually, such local prediction schemes may have better performance in predicting time series than global prediction schemes do. However, local prediction schemes only use the most recent information and ignore information bearing on far away data. As a result, the accuracy of local prediction schemes may be limited. In this paper a novel prediction approach, termed the Markov-Fourier gray model (MFGM), is proposed. The approach builds a gray model from a set of the most recent data and a Fourier series is used to fit the residuals produced by this gray model. Then, the Markov matrices are employed to encode possible global information generated also by the residuals. It is evident that MFGM can provide the best performance among existing prediction schemes. Besides, we also implemented a short-term MFGM approach, in which the Markov matrices only recorded information for a period of time instead of all data. The predictions using MFGM again are more accurate than those using short-term MFGM. Thus, it is concluded that the global information encoded in the Markov matrices indeed can provide useful information for predictions.     

On the SiO2-based gate-dielectric scaling limit forlow-standby power applications in the context of a 0.13 μm CMOS logictechnology

This paper describes a leading-edge 0.13 μm low-leakage CMOS logic technology. To achieve competitive off-state leakage current (I _off) and gate delay (T_d) performance at operating voltages (V_cc) of 1.5 V and 1.2 V, devices with 0.11 μm nominal gate length (L_g-nom) and various gate-oxide thicknesses (T_ox) were fabricated and studied. The results show that low power and memory applications are limited to oxides not thinner than 21.4 Å in order to keep acceptable off-state power consumption at V_cc=1.2 V. Specifically, two different device designs are introduced here. One design named LP (T_ox=26 Å) is targeted for V_cc=1.5 V with worst case I_off <10 pA/μm and nominal gate delay 24 ps/gate. Another design, named LP1 (T_ox=22 Å) is targeted for V_cc =1.2 V with worst case I_off<20 pA/μm and nominal gate delay 27 ps/gate. This work demonstrates n/pMOSFETs with excellent 520/210 and 390/160 μA/μm nominal drive currents at V_cc for LP and LP1, respectively. Process capability for low-power applications is demonstrated using a CMOS 6T-SRAM with 2.43 μm² cell size. In addition, intrinsic gate-oxide TDDB tests of LP1 (T _ox=22 Å) demonstrate that gate oxide reliability far exceeding 10 years is achieved for both n/pMOSFETs at T=125°C and V _cc=1.5 V     

GaAs monolithic 1.5 to 2.8 GHz tunable ring oscillator withaccurate quadrature outputs

The design, fabrication and characteristics of a 1.5 to 2.8 GHz tunable ring oscillator with two quadrature outputs are described. Tuning range is 1.3 GHz or 60.5% bandwidth. The phase difference between the two outputs is proved to be 90°. The oscillator phase noise is -81.27 dBc/Hz at 100 kHz offset from the carrier at 2.736 GHz     

钾原子的能量积聚诱导电离和双光子共振三光子电离

用染料激光激发钾蒸气 ,发现了钾原子的两种电离机制和三个电离通道 :能量积聚诱导的电离 ,4S 6S和4S 4D双光子共振三光子电离。对前两个电离通道 ,分别研究了电离谱与钾蒸气温度和激光强度的关系 ,发现了钾原子的辐射囚禁效应和钾原子电离的非线性现象 ,并给出了定性解释