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991.
首先介绍了电信网络中存在的一些主要的技术缺陷和管理缺陷;然后针对这些缺陷提出了建设一个基于SOC的网络安全管理体系的有效解决方案;最后详细描述TSOC解决方案的主要功能。  相似文献   
992.
提出了一种适用于低电源电压的新型高线性度采样开关.与传统低电压采样开关相比,这种新型采样开关不仅消除了MOS开关由于栅源电压随输入信号变化所引入的非线性,而且进一步消除了MOS开关由于阈值电压随输入信号变化引入的非线性.这是通过采用一个与采样MOS开关具有相同阈值电压的"复制"开关得以实现的.基于Chartered 0.35μm标准CMOS工艺,文中设计了一个此类新型MOS采样开关,在输入信号为0.2MHz正弦波,峰峰值为1.2V,采样时钟频率为2MHz时,无杂散动态范围达到111dB,比栅压自举开关提高了18dB;同时导通电阻的变化减小了90%.这种新型采样开关特别适用于低电压,高精度模数转换器.  相似文献   
993.
A digital calibration technique for an ultra high-speed folding and interpolating analog-to-digital converter in 0.18-μm CMOS technology is presented.The similar digital calibration techniques are taken for high 3-bit flash converter and low 5-bit folding and interpolating converter,which are based on well-designed calibration reference, calibration DAC and comparators.The spice simulation and the measured results show the ADC produces 5.9 ENOB with calibration disabled and 7.2 ENOB with calibration enabled for high-frequency wide-bandwidth analog input.  相似文献   
994.
在介绍LAC资源分配方案的基础上,对封闭模式下不同的准入控制方案进行了分析,并着重给出了一个完整的准入控制解决方案。  相似文献   
995.
周静红 《电子技术》2013,(12):55-56,51
文章主要分析了基于PLC控制的SHP系列单柱液压缸试验台,针对大多数液压缸试验台性能不稳定、速度不快、结构不紧凑等缺点,采用西门子PLC开发一套新型的液压缸试验台控制系统。该控制系统具有性能稳定、速度快、操作方便、使用寿命长等优点。  相似文献   
996.
归纳了一种通用的水下节点光通信模型,引入节点存活率作为海底观测网的可靠性指标,针对水下多分支节点较多导致的可靠性降低和铺设施工难度增加等缺点,将NEPTUNE优化为只包含两个多分支节点的交叉环拓扑。对上述两种网络的可靠性进行了仿真,结果表明,交叉环拓扑与NEPTUNE相比具有相近的可靠性,但多分支节点数量更少,便于海底观测网的供电和铺设。  相似文献   
997.
This paper proposes a novel approach, Markov Chain Monte Carlo (MCMC) sampling approximation, to deal with intractable high-dimension integral in the evidence framework applied to Support Vector Regression (SVR). Unlike traditional variational or mean field method, the proposed approach follows the idea of MCMC, firstly draws some samples from the posterior distribution on SVR??s weight vector, and then approximates the expected output integrals by finite sums. Experimental results show the proposed approach is feasible and robust to noise. It also shows the performance of proposed approach and Relevance Vector Machine (RVM) is comparable under the noise circumstances. They give better robustness compared to standard SVR.  相似文献   
998.
Emerging 2D nonvolatile Schottky-barrier-field-effect transistors (NSBFETs) are envisaged to build a promising reconfigurable in-memory architecture to mimic the brain. Herein, a vertically stacked multilayered graphene (MGr)-molybdenum disufide (MoS2)-tungsten ditelluride (WTe2) NSBFET is reported. The semimetal WTe2 with the charge-trapping effect enables the simultaneous integration of the electrode and the self-gating function. The effective Schottky barrier height offset ΔΦB is programed from ΔΦB-p = 132.6 meV to ΔΦB-n = 109.4 meV, inducing the reversed built-in electric field to make the NSBFET, so as to provide one with a multifunctional platform to integrate the nonvolatility and the reconfigurable self-powered photo response. The reversible open-circuit voltages of NSBFET synapse are programmed from −0.1 to 0.25 V and the self-powered responsivity with reversed signs is tuned from 290 to −50 mA W−1, which enables the representation of a signed weight in a single device to enrich multiple optical sensing and computing capabilities.  相似文献   
999.
Photocatalytic conversion of CO2 into fuels using pure water as the proton source is of immense potential in simultaneously addressing the climate-change crisis and realizing a carbon-neutral economy. Single-atom photocatalysts with tunable local atomic configurations and unique electronic properties have exhibited outstanding catalytic performance in the past decade. However, given their single-site features they are usually only amenable to activations involving single molecules. For CO2 photoreduction entailing complex activation and dissociation process, designing multiple active sites on a photocatalyst for both CO2 reduction and H2O dissociation simultaneously is still a daunting challenge. Herein, it is precisely construct Cu single-atom centers and two-coordinated N vacancies as dual active sites on CN (Cu1/N2CV-CN). Experimental and theoretical results show that Cu single-atom centers promote CO2 chemisorption and activation via accumulating photogenerated electrons, and the N2CV sites enhance the dissociation of H2O, thereby facilitating the conversion from COO* to COOH*. Benefiting from the dual-functional sites, the Cu1/N2CV-CN exhibits a high selectivity (98.50%) and decent CO production rate of 11.12 µmol g−1 h−1. An ingenious atomic-level design provides a platform for precisely integrating the modified catalyst with the deterministic identification of the electronic property during CO2 photoreduction process.  相似文献   
1000.
Bacterial infection and impaired angiogenesis make the treatment of diabetic foot ulcers (DFU) extremely challenging. Cationic polymers are expected to treat infected wounds due to their excellent antibacterial properties, but still, it is difficult to meet the therapeutic needs of pro-angiogenesis and anti-infections due to their simple construction units and outmoded synthesis methods. Herein, a cationic poly(pentahydropyrimidine) (PPHP) library with strong modifiability is synthesized to construct a hybrid hydrogel with synergistic therapeutic effects for the treatment of infected DFUs. It is found that the as-synthesized hybrid hydrogel can up-regulate angiogenesis-related gene (HIF-1, VEGF, and bFGFR/bFGF) expression and targeted disruption of bacterial cell membranes, which finally promotes the healing of infected DFU (wound healing rate: 92%) within 10 days. This hydrogel, thus, holds great promise in developing new strategies to significantly enhance the treatment of DFU and other bacterial-infected pathological diagnoses.  相似文献   
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