移动通信中的智能天线技术

智能天线技术已经成为移动通信领域中最具吸引力的技术之一，它能够根据所处的电磁环境，智能地调节自身参数，抑制干扰，提高天线增益，增加频谱利用率，从而改善移动通信系统的性能。介绍了智能天线的工作原理，阐述了智能天线常用的算法、数字波束成型技术、对系统性能的改善以及在移动通信系统中的应用，最后对智能天线的未来作了展望。     

Room-Temperature Metal-Catalyzed Ultrafast Gasification of Ultrathin Boron Flakes

The trivalent outer shell of boron renders this element electron-poor but chemically rich, exhibiting more than one dozen allotropes. Its 2D polymorph has been recently synthesized on metal substrates under ultrahigh vacuum and has attracted intense interest. However, probing its properties ex situ has been challenging due to the quality degradation—surface oxidation—that occurs upon exposure to ambient environments. Herein, this surface chemistry is investigated in regard to the air stability of ultrathin boron flakes on metals prepared by atmospheric-pressure chemical vapor deposition. The characteristic Volmer–Weber growth is recognized by the stacking of polygon-shaped, thin flakes as isolated islands. Significantly, the metal-catalyzed, ultrafast gasification of boron flakes at room temperature, exemplified by the complete, spontaneous vanishment of 200 nm-thick boron islands in 3 h is observed. A two-step mechanism, first oxygen-involved surface oxidation and then subsequent reactions with water forming a highly volatile boric acid layer, is unambiguously revealed by combined surface characterizations. The catalysis by metal substrates, corroborated by theoretical calculations, is attributed as the crucial cause of the unprecedented gasification. The concept of oxygen-free growth is thereby proposed for air-sensitive material growth by introducing in situ oxygen scavengers. These findings significantly expand the fundamental understanding of the surface chemistry of boron and pave the way for the chemical vapor deposition growth of hydrophobic materials.     

4G载波向5G重耕之前的5G业务覆盖能力研究

为了满足低成本建设5G广覆盖网络的需求,需要提前研究低频3G、4G网络向5G重耕的最佳方案。在没有进行重耕,因而没有理想的低频5G测试环境的情况下,采用理论分析的手段进行重耕后的覆盖能力估算。以未来L900重耕用于5G广覆盖为例,探讨了链路预算的关键设定、模型选择等问题,并通过多个本地网实际测试数据间接验证估算结果的合理性。所得结论已实际应用于某大运营商对全国900 MHz网络的规划方案,对于指导网络重耕具有重要的借鉴意义,也为面向覆盖和感知的6G网络演进及重耕提供了参考模型。     

A Supermolecular Photosensitizer with Excellent Anticancer Performance in Photodynamic Therapy

A supermolecular photosensitizer with excellent anticancer behavior when used for photodynamic therapy (PDT) is fabricated by the incorporation of zinc phthalocyanines (ZnPc) into the gallery of a layered double hydroxide (LDH). The composite material possesses uniform particle size (hydrodynamic diameter ～120 nm), and the host–guest and guest–guest interactions result in a high dispersion of ZnPc in a monomeric state in the interlayer region of the LDH matrix, with high singlet oxygen production efficiency. In vitro tests performed with HepG2 cells reveal a satisfactory PDT effectiveness of the ZnPc(1.5%)/LDH composite photosensitizer: a cellular damage as high as 85.7% is achieved with a rather low dosage of ZnPc (10 μg/mL). An extraordinarily high specific efficacy is demonstrated (31.59 μg^?1 (J/cm²)^?1), which is over 185.5% enhancement compared with the previously reported photosensitizers under similar test conditions. Furthermore, an in vivo study of the ZnPc(1.5%)/LDH demonstrates excellent PDT performance with an ultra‐low dose (0.3 mg/kg) and a low optical fluence rate (54 J/cm²). In addition, the ZnPc/LDH photosensitizer displays high stability, good biocompatibility, and low cytotoxicity, which would guarantee its practical application. Therefore, this work provides a facile approach for design and fabrication of inorganic–organic supermolecular materials with greatly enhanced anticancer behavior.     

量化对GPS接收机捕获性能的影响

由于接收机输入端的信噪比对接收机的捕获性能具有很重要的意义,所以要尽量减少接收机输入端信噪比的损失,文中给出了含高斯白噪声的GPS信号经过不同量化位数和量化电平的量化器后的输出信噪比计算公式,在此基础上分析其对接收机捕获性能的影响,最后通过仿真实验说明接收机可以在不影响捕获性能的情况下尽量选择合适的量化位数和量化门限。实验结果也为量化器的设计提供了重要的技术参考。     

风光互补移动电源

针对户外旅行爱好者可能发生的用电短缺的情况,设计了一套便携式风光互补移动电源的系统。该系统充分利用户外易于获得的风能和光能,通过风力发电机和太阳能电池板将风能和太阳能转化为电能的形式存储在锂电池中,并且电路具有过充、温度保护功能。     

MIM有源薄膜器件及阵列的基础研究

本文详细分析了MIM有源薄膜器件及阵列的工作原理、工艺过程和器件性能.根据一种液晶有源薄膜器件阵列设计模型,设计和研制出了MIM单管性能和实验用7×5象素MIM有源矩阵液晶显示板.此显示板具有显示一定图形的功能.     

Novel heterojunction real-space transfer logic transistorstructures: a model-based investigation

Ensemble Monte Carlo simulations are employed in order to explore the feasibility of a novel real-space transfer logic transistor (RSTLT) structure. The operational principles of the proposed RSTLT are based on the concept of hot electron real-space transfer (RST), including the fact that the spatial location of electron RST is determined by applied bias and heterointerface energy barrier height in a multiterminal heterojunction microstructure. The results of two-dimensional, self-consistent steady-state and transient simulations demonstrate that the proposed RSTLT features ultrafast current switching which can be used to realize NOT/EQUIVALENT logic functions in a single heterojunction device. The logic operation is easily extended to NOR/AND functions. A conservative estimate of the characteristic delay time for current switching is ~3 ps in the proposed RSTLT structure     

数字调谐系统在组合音响上的应用

本文介绍了NEC公司大规模专用集成电路μPD1715G——016及其在组合音响上的应用,讨论了设计中的几点关键性问题,并分析了解决问题的方法和途径。     

视盘机测试盘制作与应用测量

视盘机测试盘制作的好坏与所作的测试盘能否正确和精确地用于测量是直接相关的。根据原电子部电子行业标准计划,1997年三所”研制了VCD视盘机测试盘。根据原电子部［1998」038号文1998年11月至12月底,经过二个月的实际工作,又制作了超级VCD视盘机电性能测试盘。在这些测试盘制作过程中,特别是在超级VCD电性能测试盘制作中,就压缩编码系统的选择、信源及其产生、亮度清晰度测试卡信号的录制。信噪比测试信号的录制和应用测量。350线多波群频率点和Y扫频频标选择等,取得了不少经验和体会。l压缩编码系统的选择超级VCD视盘存储的是…