宽带智能天线系统中的频率补偿技术

在无线通信中,智能天线系统在抑制窄带多径干扰方面具有得天独厚的优势,但是用于宽带无线通信系统中时,就需要采用频率补偿方法.重点介绍基于频谱分解、聚焦和插值算法的补偿技术,并对这3种频率补偿技术的性能进行比较,结果表明在应用补偿技术的系统中,系统性能有显著的改善,其中插值算法具有最优的性能.     

金属化膜脉冲电容器组的性能可靠性

基于金属化膜电容器的特点，提出了金属化膜电容器组的性能可靠性，并分两种情况讨论了性能可靠性的估计方法。金属化膜脉冲电容器组性能可靠性的提出，有效地解决了电容器组在使用过程中可靠性的评价问题。可以为电容器组寿命预计、维修提供依据。     

氧化铝模板法制备Ge纳米线

采用氧化铝模板法结合具有高真空背景的低压化学气相沉积技术制备出 Ge纳米线 .在氧化铝模板的背面喷金作为催化剂 ,合成了 Ge纳米线 .采用原子力显微镜、X射线衍射、透射电镜、能量散射谱等手段对 Ge纳米线进行了分析 .Ge纳米线的直径约为 30 nm,长度超过 6 0 0 nm.对 Ge纳米线的生长机理进行了探讨 .     

对电源及温度不敏感的电流可调的CMOS电荷泵电路的设计

设计了一种电流可调的CMOS电荷泵电路 ,其中采用了带隙基准源、低drop out调压器及电容式直流 直流电压升压器为电荷泵电路提供电源电压 ,此电压不受外部供电电压及温度变化的影响 ;同时 ,电荷泵电路中的参考电流源本身也对温度变化不敏感 .电路设计采用 0 18μm 1 8V标准的数字CMOS工艺 .模拟结果表明电路性能令人满意.     

Electrical and Thermal Transport Properties of Ge1–xPbxCuySbyTeSe2y

Balancing the contradictory relationship between thermoelectric parameters, such as effective mass and carrier mobility, is a challenge to optimize thermoelectric performance. Herein, the exceptional thermoelectric performance is realized in GeTe through collaboratively optimizing the carrier and phonon transport via stepwise alloying Pb and CuSbSe₂. The formation energy of Ge vacancy is efficiently bolstered by alloying Pb, which reduces carrier density and carrier scattering to maintain superior carrier mobility in GeTe. Additionally, CuSbSe₂, acting as an n-type dopant, further modulates carrier density and validly equilibrates carrier mobility and effective mass. Accordingly, the promising power factor of 45 µW cm⁻¹ K⁻² is achieved at 723 K. Meanwhile, point defects are found to significantly suppress phonons transport to descend lattice thermal conductivity by Pb and CuSbSe₂ alloying, which barely impacts the carrier mobility. A combination with superior carrier mobility and lower lattice thermal conductivity, a maximum ZT of 2.2 is attained in Ge_0.925Pb_0.075Cu_0.005Sb_0.005TeSe_0.01, which corresponds to a 100% promotion compared with that of intrinsic GeTe. This study provides a new indicator for optimizing carrier and phonon transport properties by balancing interrelated thermoelectric parameters.     

Magnetoelectric Coupling for Metal–Air Batteries

Metal–air batteries have become one of the new potential sources of electrochemical energy due to the excellent electrochemical characteristics, environmental friendliness and cheap cost. Whereas, the commercialization of the metal–air batteries is still subject to the sluggish kinetics on air electrode and hydrogen evolution corrosion as well as dendrite growth of metal anode. Recently, the applied magnetic field, as a technology for transferring energy across physical space, receives more attention, can improve the performance of metal–air batteries by promoting mass transfer, accelerating charge transfer and enhancing electrocatalytic ability based on magnetohydrodynamic effect, Kelvin force effect, Hall effect, Spin selectivity effect, Maxwell stress effect and Magnetothermal effect. This review provides the recent progress in the research on the relative mechanism and characteristic of the magnetic field in the metal–air batteries.     

Construction of VS2/VOx Heterostructure via Hydrolysis-Oxidation Coupling Reaction with Superior Sodium Storage Properties

Heterostructure engineering is one of the most promising modification strategies for reinforcing Na⁺ storage of transition metal sulfides. Herein, based on the spontaneous hydrolysis-oxidation coupling reaction of transition metal sulfides in aqueous media, a VO_x layer is induced and formed on the surface of VS₂, realizing tight combination of VS₂ and VO_x at the nanoscale and constructing homologous VS₂/VO_x heterostructure. Benefiting from the built-in electric field at the heterointerfaces, high chemical stability of VO_x, and high electrical conductivity of VS₂, the obtained VS₂/VO_x electrode exhibits superior cycling stability and rate properties. In particular, the VS₂/VO_x anode shows a high capacity of 878.2 mAh g⁻¹ after 200 cycles at 0.2 A g⁻¹. It also exhibits long cycling life (721.6 mAh g⁻¹ capacity retained after 1000 cycles at 2 A g⁻¹) and ultrahigh rate property (up to 654.8 mAh g⁻¹ at 10 A g⁻¹). Density functional theory calculations show that the formation of heterostructures reduces the activation energy for Na⁺ migration and increases the electrical conductivity of the material, which accelerates the ion/electron transfer and improves the reaction kinetics of the VS₂/VO_x electrode.     

Molecular-level Designed Polymer Electrolyte for High-Voltage Lithium–Metal Solid-State Batteries

In solid polymer electrolytes (SPEs) based Li–metal batteries, the inhomogeneous migration of dual-ion in the cell results in large concentration polarization and reduces interfacial stability during cycling. A special molecular-level designed polymer electrolyte (MDPE) is proposed by embedding a special functional group (4-vinylbenzotrifluoride) in the polycarbonate base. In MDPE, the polymer matrix obtained by copolymerization of vinylidene carbonate and 4-vinylbenzotrifluoride is coupled with the anion of lithium-salt by hydrogen bonding and the “σ-hole” effect of the C F bond. This intermolecular interaction limits the migration of the anion and increases the ionic transfer number of MDPE (t_Li⁺ = 0.76). The mechanisms of the enhanced t_Li⁺ of MDPE are profoundly understood by conducting first-principles density functional theory calculation. Furthermore, MDPE has an electrochemical stability window (4.9 V) and excellent electrochemical stability with Li–metal due to the CO group and trifluoromethylbenzene (ph-CF₃) of the polymer matrix. Benefited from these merits, LiNi_0.8Co_0.1Mn_0.1O₂-based solid-state cells with the MDPE as both the electrolyte host and electrode binder exhibit good rate and cycling performance. This study demonstrates that polymer electrolytes designed at the molecular level can provide a broader platform for the high-performance design needs of lithium batteries.     

一种含有安全可信任中心的量子秘密共享方案

量子秘密共享（Quantum secret sharing , QSS）可以在不完全信任的通信双方间传递密钥,是量子密码的一个重要分支。本文提出一种含有安全可信任中心的QSS方案。其中,中心能够产生并提供量子态,也能够测量并提取量子态信息。通信用户（Alice、Bob和Charlie）不拥有量子比特产生器和测量器,只需通过幺正操作和交换操作实现密钥传输和窃听防范;同时,Bob和Charlie必须合作才能获得正确的密钥。理论分析表明该方案可有效地抵御截取重发攻击、纠缠测量攻击和关联提取攻击等常见攻击策略;由于方案减少了量子比特产生器和测量器的数量,降低了量子通信的费用。这将为量子秘密共享实用化提供一种可参考的方法。     

一种低成本单兵便携式导弹模拟训练器方案

为了训练射手对单兵便携式导弹的瞄准、跟踪和击发等操作手法,设计了一种低成本模拟训练器。描述了单兵便携式导弹的作战使用过程;提出了模拟训练器的系统组成和工作原理;建立了训练成绩的评定模型。该模拟训练器无惯性器件和传感器,成本低,可靠性好;外形和体感与真实装备相同,可进行成绩评定和记录,可远程对训练过程进行实时监控和指导,可室内使用,也可室外使用。