Encoding Information on the Excited State of a Molecular Spin Chain

The quantum states of nano-objects can drive electrical transport properties across lateral and local-probe junctions. This raises the prospect, in a solid-state device, of electrically encoding information at the quantum level using spin-flip excitations between electron spins. However, this electronic state has no defined magnetic orientation and is short-lived. Using a novel vertical nanojunction process, these limitations are overcome and this steady-state capability is experimentally demonstrated in solid-state spintronic devices. The excited quantum state of a spin chain formed by Co phthalocyanine molecules coupled to a ferromagnetic electrode constitutes a distinct magnetic unit endowed with a coercive field. This generates a specific steady-state magnetoresistance trace that is tied to the spin-flip conductance channel, and is opposite in sign to the ground state magnetoresistance term, as expected from spin excitation transition rules. The experimental 5.9 meV thermal energy barrier between the ground and excited spin states is confirmed by density functional theory, in line with macrospin phenomenological modeling of magnetotransport results. This low-voltage control over a spin chain's quantum state and spintronic contribution lay a path for transmitting spin wave-encoded information across molecular layers in devices. It should also stimulate quantum prospects for the antiferromagnetic spintronics and oxides electronics communities.     

Proton irradiation of CdTe thin film photovoltaics deposited on cerium‐doped space glass

Space photovoltaics is dominated by multi‐junction (III‐V) technology. However, emerging applications will require solar arrays with high specific power (kW/kg), flexibility in stowage and deployment, and a significantly lower cost than the current III‐V technology offers. This research demonstrates direct deposition of thin film CdTe onto the radiation‐hard cover glass that is normally laminated to any solar cell deployed in space. Four CdTe samples, with 9 defined contact device areas of 0.25 cm², were irradiated with protons of 0.5‐MeV energy and varying fluences. At the lowest fluence, 1 × 10¹² cm⁻², the relative efficiency of the solar cells was 95%. Increasing the proton fluence to 1 × 10¹³ cm⁻² and then 1 × 10¹⁴ cm⁻² decreased the solar cell efficiency to 82% and 4%, respectively. At the fluence of 1 × 10¹³ cm⁻², carrier concentration was reduced by an order of magnitude. Solar Cell Capacitance Simulator (SCAPS) modelling obtained a good fit from a reduction in shallow acceptor concentration with no change in the deep trap defect concentration. The more highly irradiated devices resulted in a buried junction characteristic of the external quantum efficiency, indicating further deterioration of the acceptor doping. This is explained by compensation from interstitial H⁺ formed by the proton absorption. An anneal of the 1 × 10¹⁴ cm⁻² fluence devices gave an efficiency increase from 4% to 73% of the pre‐irradiated levels, indicating that the compensation was reversible. CdTe with its rapid recovery through annealing demonstrates a radiation hardness to protons that is far superior to conventional multi‐junction III‐V solar cells.     

新形势下中国移动城域传送网演变之路

面对急剧变化的业务需求,中国移动城域传送网该何去何从？本文从网络结构、新技术演进等方面进行了分析和研究,并提出了其网络演进思路和方案,供网络规划建设人员参考。     

网络与通信技术在计算机控制中的应用

在社会经济高速发展的支持下,我国网络与通信技术高速发展,并且在发展中逐渐实现了两种技术的结合应用,大大提升了网络与通信技术的应用价值。文章对网络与通信技术进行分析,研究网络与通信技术在计算机控制中应用的时代背景和具体应用,并对其未来发展进行了概述,以促进计算机控制领域的科学化发展。     

Hardware trojans in 3-D ICs due to NBTI effects and countermeasure

Going vertical as in 3-D IC design, reduces the distance between vertical active silicon dies, allowing more dies to be placed closer to each other. However, putting 2-D IC into three-dimensional structure leads to thermal accumulation due to closer proximity of active silicon layers. Also the top die experiences a longer heat dissipation path. All these contribute to higher and non-uniform temperature variations in 3-D IC; higher temperature exacerbates negative bias temperature instability (NBTI). NBTI degrades CMOS transistor parameters such as delay, drain current and threshold voltage. While the impact of transistor aging is well understood from the device point of view, very little is known about its impact on security. We demonstrated that a hardware intruder could leverage this phenomenon to trigger the payload, without requiring a separate triggering circuit. In this paper we provide a detailed analysis on how tiers of 3-D ICs can be subject to exacerbated NBTI. We proposed to embed threshold voltage extractor circuit in conjunction with a novel NBTI-mitigation scheme as a countermeasure against such anticipated Trojans. We validated through post-layout and Monty Carlo simulations using 45 nm technology that our proposed solution against NBTI effects can compensate the NBTI-effects in the 3-D ICs. With the area overhead of 7% implemented in Mod-3 counter, our proposed solution can completely tolerate NBTI-induced degraded threshold voltage shift of up to 60%.     

The use of mobile technology for online shopping and entertainment among older adults in Finland

Older adults are becoming an important market segment for all internet-based services, but few studies to date have considered older adults as online shoppers and users of entertainment media. Utilising the concept of life course, this article investigates the use of mobile technologies for online shopping and entertainment among consumers aged 55 to 74. The data were collected with a web-based survey completed by a panel of respondents representing Finnish television viewers (N = 322). The results reveal that consumers aged 55 to 74 use a smartphone or tablet to purchase products or services online as often as younger consumers. In contrast, listening to internet radio and watching videos or programmes online with a smartphone or tablet are most typical for younger male consumers. The results demonstrate that mobile-based online shopping is best predicted by age, higher education, and household type (children living at home), and use of entertainment media by age and gender.     

信号处理技术的若干进展(国内)

本文着重介绍我国在信号处理领域中有关的若干专题的研究进展。这些专题包括离散变换,谱估计理论,空间谱估计,自适应滤波算法和数字滤波器。文中对数字信号处理硬件设计方面的进展亦做了介绍;同时就信号处理在语声处理、文字识别、图像处理和计算机视觉方面的应用成果也做了概要的说明。     

薄膜全耗尽SOI短沟道MOSFET准二维电流模型

本文在分析薄膜全耗尽SOI器件特殊物理效应的基础上,建立了可细致处理饱和区工作特性的准二维电流模型。该模型包括了场效应载流子迁移率、速度饱和以及短沟道效应等物理效应,可以描述薄膜全耗尽SOI器件所特有的膜厚效应、正背栅耦合(背栅效应)等对器件特性的影响,并且保证了电流、电导及其导数在饱和点的连续性。将模型模拟计算结果与二维器件数值模拟结果进行了对比,在整个工作区域(不考虑载流子碰撞离化的情况下)二者吻合得很好。     

Compressed Digital Video:Accelerating the Video Communications Revolution

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现代吸气剂及其应用技术

近年来，新型叹气剂的开发和应用均取得长足的进步。吸气剂在真空技术领域内愈加显示出它的重要性。本文介绍了吸气剂的吸气机理，吸气材料对氢及其同位素之间的吸附、解吸的平衡理论问题，蒸散型吸气剂和非蒸散型吸气剂的最新发展和应用等．