RTD/HPT光控单-双稳转换逻辑单元

以光接收器件代替RTD MOBILE(RTD单-双稳转换逻辑单元)电路中的HEMT或HBT,可构成光控MOBILE电路。在比较了四种光控MOBILE结构的基础上,选择RTD/HPT光控结构,重点分析讨论了RTD/HPT光控MOBILE的工作原理,当光控MOBILE的输入光功率超过一个临界值时,MOBILE的输出电压便会从高电平跳变到低电平;由HPT光增益理论分析了提高HPT性能的措施以及HPT设计中应该注意的问题;介绍了以Si光三极管代替HPT,通过模拟实验,验证了RTD/HPT光控MOBILE的逻辑功能。     

基于FPGA的RFID板级标签设计与实现

在分析射频识别原理和特点的基础上,讨论超高频射频识别系统中电子标签设计技术,并采用EP1C6Q240FPGA对超高频电子标签进行了板级设计及其实现.利用Verilog语言实现了标签数字电路,并在板级标签中进行了验证.测试结果表明,该设计实现了ISO18000-6C标准的标签读写功能,读写性能优异,为下一步设计出符合该标准的电子标签芯片提供了有力保证.     

Homogeneous and Disordered Assembly of Densely Packed Nanocrystals

A homogeneous and disordered assembly of densely packed nanocrystals is generated without the assistance of organic molecules, from an aqueous solution at room temperature. The densely packed nanocrystals of tin dioxide (SnO₂) and titanium dioxide (TiO₂), 2–3 nm in size, form glassy macroscopic transparent objects of 2–10 mm. The monodisperse nanocrystals, which have a surface hydrated layer and are synthesized in aqueous solution, are densely packed in an homogeneous and disordered assembly through the evaporation of water as the dispersion medium. The formation of transparent bulk objects on the macroscopic scale originates from the homogeneous and disordered nature of the densely packed nanocrystals. The resultant homogeneous architectures are distinguishable from the typical inhomogeneous and disordered aggregates of nanoparticles observed after evaporation of the dispersion medium. Among superstructures based on nanocrystals, such as superlattices and mesocrystals, the resultant homogeneous and disordered assembly can be regarded as a new class of solid‐state material.     

一种新型的超宽带微带转共面带状线巴伦

设计了一种新型的微带转共面带状线（coplanarStripLine以下简称CPS）的巴伦结构。它可以应用于多种常用的介质板上,具有结构紧凑、超宽带、低损耗的特点。制作了一个两端为500微带线的背靠背电路,测试得插入损耗（S21）〉-1dB、回波损耗（S11）〈-15dB的带宽为2．7GHz～7．3GHz,S21〉-4dB、S11〈-10dB的带宽为1．4GHz～15．6GHz。     

轴向输出相对论磁控管真空室过渡段设计

相对于径向输出相对论磁控管而言,轴向输出相对论磁控管具有结构紧凑、高阻抗、角向均匀性、工作模式稳定以及高功率输出等一系列优点。但由于外加磁体对轴向输出端半径的限制,导致真空室的轴向长度大于磁控管的轴向长度,为了实现工程应用,一段较短的轴向输出过渡段被设计。文中主要是通过仿真软件仿真找到较为有效的过渡段设计以实现在S 波段π 模工作模式下的轴向输出相对论磁控管的能量有效输出。整个器件的轴向输出段的总长度为378 mm,输出端圆柱波导的半径为73.8 mm。在三维粒子模拟下得到一种较为有效的过渡段结构,功率转换效率为28.7%,相应的输出功率为1.371GW,辐射模式为TE01 模。     

Earth‐Abundant and Durable Nanoporous Catalyst for Exhaust‐Gas Conversion

Precious metals (Pt and Pd) and rare earth elements (Ce in the form of CeO₂) are typical materials for heterogeneous exhaust‐gas catalysts in automotive systems. However, their limited resources and high market‐driven prices are principal issues in realizing the path toward a more sustainable society. In this regard, herein, a nanoporous NiCuMnO catalyst, which is both abundant and durable, is synthesized by one‐step free dealloying. The catalyst thus developed exhibits catalytic activity and durability for NO reduction and CO oxidation. Microstructure characterization indicates a distinct structural feature: catalytically active Cu/CuO regions are tangled with a stable nanoporous NiMnO network after activation. The results obtained by in situ transmission electron microscopy during NO reduction clearly capture the unique reaction‐induced self‐transformation of the nanostructure. This finding can possibly pave the way for the design of new catalysts for the conversion of exhaust gas based on the element strategy.     

Efficient and Stable Bifunctional Electrocatalysts Ni/NixMy (M = P,S) for Overall Water Splitting

Development of easy‐to‐make, highly active, and stable bifunctional electrocatalysts for water splitting is important for future renewable energy systems. Three‐dimension (3D) porous Ni/Ni₈P₃ and Ni/Ni₉S₈ electrodes are prepared by sequential treatment of commercial Ni‐foam with acid activation, followed by phosphorization or sulfurization. The resultant materials can act as self‐supported bifunctional electrocatalytic electrodes for direct water splitting with excellent activity toward oxygen evolution reaction and hydrogen evolution reaction in alkaline media. Stable performance can be maintained for at least 24 h, illustrating their versatile and practical nature for clean energy generation. Furthermore, an advanced water electrolyzer through exploiting Ni/Ni₈P₃ as both anode and cathode is fabricated, which requires a cell voltage of 1.61 V to deliver a 10 mA cm^?2 water splitting current density in 1.0 m KOH solution. This performance is significantly better than that of the noble metal benchmark—integrated Ni/IrO₂ and Ni/Pt–C electrodes. Therefore, these bifunctional electrodes have significant potential for realistic large‐scale production of hydrogen as a replacement clean fuel to polluting and limited fossil‐fuels.     

Surface‐Shielding Nanostructures Derived from Self‐Assembled Block Copolymers Enable Reliable Plasma Doping for Few‐Layer Transition Metal Dichalcogenides

Precise modulation of electrical and optical properties of 2D transition metal dichalcogenides (TMDs) is required for their application to high‐performance devices. Although conventional plasma‐based doping methods have provided excellent controllability and reproducibility for bulk or relatively thick TMDs, the application of plasma doping for ultrathin few‐layer TMDs has been hindered by serious degradation of their properties. Herein, a reliable and universal doping route is reported for few‐layer TMDs by employing surface‐shielding nanostructures during a plasma‐doping process. It is shown that the surface‐protection oxidized polydimethylsiloxane nanostructures obtained from the sub‐20 nm self‐assembly of Si‐containing block copolymers can preserve the integrity of 2D TMDs and maintain high mobility while affording extensive control over the doping level. For example, the self‐assembled nanostructures form periodically arranged plasma‐blocking and plasma‐accepting nanoscale regions for realizing modulated plasma doping on few‐layer MoS₂, controlling the n‐doping level of few‐layer MoS₂ from 1.9 × 10¹¹ cm^?2 to 8.1 × 10¹¹ cm^?2 via the local generation of extra sulfur vacancies without compromising the carrier mobility.     

Understanding the Structural Evolution and Redox Mechanism of a NaFeO2–NaCoO2 Solid Solution for Sodium‐Ion Batteries

Na‐ion batteries have become promising candidates for large‐scale energy‐storage systems because of the abundant Na resources and they have attracted considerable academic interest because of their unique behavior, such as their electrochemical activity for the Fe³⁺/Fe⁴⁺ redox couple. The high‐rate performance derived from the low Lewis‐acidity of the Na⁺ ions is another advantage of Na‐ion batteries and has been demonstrated in NaFe_1/2Co_1/2O₂ solutions. Here, a solid solution of NaFeO₂‐NaCoO₂ is synthesized and the mechanisms behind their excellent electrochemical performance are studied in comparison to those of their respective end‐members. The combined analysis of operando X‐ray diffraction, ex situ X‐ray absorption spectroscopy, and density functional theory (DFT) calculations for Na_{1– x} Fe_1/2Co_1/2O₂ reveals that the O3‐type phase transforms into a P3‐type phase coupled with Na⁺/vacancy ordering, which has not been observed in O3‐type NaFeO₂. The substitution of Co for Fe stabilizes the P3‐type phase formed by sodium extraction and could suppress the irreversible structural change that is usually observed in O3‐type NaFeO₂, resulting in a better cycle retention and higher rate performance. Although no ordering of the transition metal ions is seen in the neutron diffraction experiments, as supported by Monte‐Carlo simulations, the formation of a superlattice originating from the Na⁺/vacancy ordering is found by synchrotron X‐ray diffraction for Na_0.5Fe_1/2Co_1/2O₂, which may involve a potential step in the charge/discharge profiles.     

An O2 Self‐Sufficient Biomimetic Nanoplatform for Highly Specific and Efficient Photodynamic Therapy

Conventional oxygen‐dependent photodynamic therapy (PDT) has faced severe challenges because of the non‐specificity of most available photosensitizers (PSs) and the hypoxic nature of tumor tissues. Here, an O₂ self‐sufficient cell‐like biomimetic nanoplatform (CAT‐PS‐ZIF@Mem) consisting of the cancer cell membrane (Mem) and a cytoskeleton‐like porous zeolitic imidazolate framework (ZIF‐8) with the embedded catalase (CAT) protein molecules and Al(III) phthalocyanine chloride tetrasulfonic acid (AlPcS₄, defined as PS) is developed. Because of the immunological response and homologous targeting abilities of the cancer cell membrane, CAT‐PS‐ZIF@Mem is selectively accumulated at the tumor site and taken up effectively by tumor cells after intravenous injection. After the intracellular H₂O₂ penetration into the framework, it is catalyzed by CAT to produce O₂ at the hypoxic tumor site, facilitating the generation of toxic ¹O₂ for highly effective PDT in vivo under near‐infrared irradiation. By integrating the immune escape, cell homologous recognition, and O₂ self‐sufficiency, this cell‐like biomimetic nanoplatform demonstrates highly specific and efficient PDT against hypoxic tumor cells with much reduced side‐effect on normal tissues.