基于粒矩阵的多输入多输出真值表快速并行约简算法

真值表是表征逻辑输入与输出之间因果关系的重要工具,真值表约简在数字逻辑电路的分析与设计中具有重要意义.该文将真值表看作逻辑信息系统,将真值表约简转化为逻辑信息系统的最简规则获取.采用粒计算分层粒化的思想,在不同粒度下,利用粒矩阵的知识表示形式、粒矩阵中的启发式知识以及粒矩阵运算,设计了多输入多输出真值表快速并行约简算法.以发光二极管七段数字显示器为例进行了算法说明,通过数学证明和算法复杂性分析证明了算法的正确性和有效性.     

Hybrid Organic/Inorganic Nanostructures for Highly Sensitive Photoelectrochemical Detection of Dissolved Oxygen in Aqueous Media

Precise, reliable, and remote measurement of dissolved oxygen in aqueous media is of great importance for many industrial, environmental, and biological applications. In particular, photoelectrochemical sensors working in differential mode have recently demonstrated promising properties, in terms of stability, sensitivity, and application potential. Here, a new approach is presented, combining visible light sensitivity, efficient photocurrent generation, and solution‐processed fabrication methods of conjugated polymers, with charge carriers selectivity, energetic alignment favorable to efficient interfacial charge transfer and high surface area achievable by using metal oxide nanostructures. Extensive characterization and optimization of the hybrid organic/inorganic system are carried out, leading to the realization of an oxygen sensor device, based on nanostructured palladium oxide/poly[(9,9‐dioctylfluorenyl‐2,7‐diyl)‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole]/[6,6]phenyl‐C61‐butyric acid methyl ester (PdO/APFO‐3:PCBM) as materials of choice. State‐of‐the‐art sensitivity, amounting at ?5.87 μA cm^?2 ppm^?1, low background signal, in the order of ?4.85 μA cm^?2, good electrochemical stability for more than 2 h of continuous functioning and high reproducibility of the signal over the pH 1 to 10 range, are reported, making the hybrid device suitable for several practical uses. The results fully validate the mixed organic/inorganic approach for photoelectrochemical applications, and pave the way for its further exploitation in fields like waste water treatment, environmental monitoring, and water splitting.     

Reduction‐Sensitive Dextran Nanogels Aimed for Intracellular Delivery of Antigens

Targeting of antigens to dendritic cells (DCs) to induce strong cellular immune response can be established by loading in a nano‐sized carrier and keeping the antigen associated with the particles until they are internalized by DCs. In the present study, a model antigen (ovalbumin, OVA) is immobilized in cationic dextran nanogels via disulfide bonds. These bonds are stable in the extracellular environment but are reduced in the cytosol of DCs due to the presence of glutathione. Reversible immobilization of OVA in the nanogels is demonstrated by the fact that hardly any release of the protein occurred at pH 7 in the absence of glutathione, whereas rapid release of OVA occurs once the nanogels are incubated in buffer with glutathione. Furthermore, these OVA conjugated nanogels show intracellular release of the antigen in DCs and boost the MHC class I antigen presentation, demonstrating the feasibility of this concept for the aimed intracellular antigen delivery.     

Controllable Fabrication of Transparent Macroporous Graphene Thin Films and Versatile Applications as a Conducting Platform

Graphene sheets have been demonstrated to be the building blocks for various assembly structures, which eventually determine the macroscopic properties of graphene materials. As a new assembly structure, transparent macroporous graphene thin films (MGTFs) are not readily prepared due to the restacking tendency of graphene sheets during processing. Here, an ice crystal‐induced phase separation process is proposed for preparation of transparent MGTFs. The ice crystal‐induced phase separation process exhibits several unique features, including efficient prevention of graphene oxide restacking, easy control on the transparency of the MGTFs, and wide applicability to substrates. It is shown that the MGTFs can be used as porous scaffold with high conductivity for electrochemical deposition of various semiconductors and rare metal nanoparticles such as CdSe, ZnO, and Pt, as well as successive deposition of different materials. Notably, the macroporous structures bestow the MGTFs and the nanoparticle‐decorated MGTFs (i.e., Pt@MGTF and CdSe@MGTF) enhanced performance as electrode for oxygen reduction reaction and photoelectrochemical H₂ generation.     

Flexible Asymmetric Supercapacitor Based on Structure‐Optimized Mn3O4/Reduced Graphene Oxide Nanohybrid Paper with High Energy and Power Density

A highly flexible Mn₃O₄/reduced graphene oxide (rGO) nanohybrid paper with high electrical conductivity and high mass loading of Mn₃O₄ nanofibers (0.71 g cm^?3) is developed via a facile gel formation and electrochemical reduction process, which is low‐cost, environmental friendly, and easy to scale up. Confined Mn₃O₄ nanofibers are well dispersed within the rGO sheets, which demonstrate to be a promising cathode material for flexible asymmetric supercapacitors (ASCs). When coupled with an electrochemically reduced rGO paper as the anode, a flexible ASC device, based on the Mn₃O₄/rGO nanohybrid paper as the cathode, is assembled; and it demonstrates remarkable electrochemical performance: a high volumetric capacitance of 54.6 F cm^?3 (546.05 mF cm^?2), and remarkable volumetric energy and power density (0.0055 Wh cm^?3 and 10.95 W cm^?3) being achieved with excellent cycling ability. The nanohybrid paper shows great improvement for flexible energy devices in terms of electrochemical properties.     

Avalanche‐Discharge‐Induced Electrical Forming in Tantalum Oxide‐Based Metal–Insulator–Metal Structures

Oxide‐based metal–insulator–metal structures are of special interest for future resistive random‐access memories. In such cells, redox processes on the nanoscale occur during resistive switching, which are initiated by the reversible movement of native donors, such as oxygen vacancies. The formation of these filaments is mainly attributed to an enhanced oxygen diffusion due to Joule heating in an electric field or due to electrical breakdown. Here, the development of a dendrite‐like structure, which is induced by an avalanche discharge between the top electrode and the Ta₂O_5‐x layer, is presented, which occurs instead of a local breakdown between top and bottom electrode. The dendrite‐like structure evolves primarily at structures with a pronounced interface adsorbate layer. Furthermore, local conductive atomic force microscopy reveals that the entire dendrite region becomes conductive. Via spectromicroscopy it is demonstrated that the subsequent switching is caused by a valence change between Ta⁴⁺ and Ta⁵⁺, which takes place over the entire former Pt/Ta₂O_5‐x interface of the dendrite‐like structure.     

局部投影降噪算法参数的确定及其应用

针对水声信号的非线性特征,采用局部投影降噪算法研究了舰船辐射噪声的非线性降噪问题.在分析局部投影降噪算法有关参数的选择对降噪效果影响的基础上,研究了局部投影邻域半径参数的估计.提出一种适合水声信号降噪的邻域半径估计算法,即通过估算信号的噪声强度确定局部投影的邻域半径.对Logistic模型和实际舰船信号进行降噪处理,结...     

压电主动控制在减振和降噪中的应用

利用压电主动控制进行减振和降噪实验具有广阔的发展前景.该文设计了3个相关的方案:简支梁的减振、铝板的降噪和基座的减振.实验结果显示,对于单频信号减振和降噪的效果均可达90%,证明了通过压电主动控制来实现单频的减振和降噪的可行性和显著性.     

基于LabVIEW的标签差分雷达截面分析与测量

差分雷达截面(ARCS)是描述无源超高频射频识别(UHF RFID)标签性能的重要参数,它决定标签到阅读器的反向链路误码率.但是,没有直接测量ARCS的方法,需要采取间接方式进行测量.基于NI的射频板卡,开发了标签反射矢量信号分析软件,给出△RCS的测量方法,并对贴附物材料及发送功率对ARCS的影响进行了分析和测量.     

Mild generation of selenolate nucleophiles by thiol reduction of diselenides: convenient syntheses of selenyl-substituted aryl aldehydes

Various selenyl-substituted aryl aldehydes were obtained using dithiothreitol (DTT) as a reducing agent for diselenides in the presence of a base. For electron-deficient haloaryl aldehydes, a weak base, such as K₂CO₃, performed well. However, for electron-rich haloaryl aldehydes, a stronger base, such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), was required for successful substitution. The selenyl-substitution of heteroaryl substrates were also investigated to obtain satisfactory yields of the desired products.