An ultra-wideband 6–14 GHz frequency modulated continuous wave primary radar with 3 cm range resolution

This paper describes the design and verification of an ultra-wideband 6–14 GHz frequency modulated continuous wave (FMCW) primary radar system with very high range resolution. The design and measurement results of the utilized signal generator and receiver are presented. The signal generator features a 86% relative continuous tuning range and average phase noise of −106 dBc/Hz at 1 MHz offset to the carrier. The radar system utilizes a hybrid structure where the voltage controlled oscillator was fabricated using 130 nm SiGe BiCMOS technology and the lower frequency components are off-the-shelf. Free field measurements of the radar showcase an unprecedented combination of 3 cm range resolution, low phase noise and low operating frequency of 6–14 GHz for inherently higher range.     

柠檬酸盐对阳极箔形成速度与比电容的影响

为了提高铝电解电容器用高压阳极箔形成速度与比电容,将水合处理后的腐蚀箔在95℃、2 g/L柠檬酸钠去离子水溶液中浸泡5 min,在530 V电压化成时,形成时间缩短约2 min,化成箔比电容由0.556×10–6 F.cm–2提高至0.584×10–6 F.cm–2,阳极氧化铝膜的结构与性能得到改善。     

有线电视系统中段电平凸起原因探讨

有线电视网络末端中段电平凸起现象非常普遍，对有线电视信号的传输质量有一定的影响。通常认为均衡特性和频率衰减特性的差异是造成这种现象的主要原因，很难抑制。通过实践和对测试数据的分析，认为电路器件和电缆接头进水是造成这种现象的一个重要原因。     

Metal-Organic Framework Thin Films Grown on Functionalized Graphene as Solid-State Ion-Gated FETs

The unique properties of 2D-materials like graphene are exploited in various electronic devices. In sensor applications, graphene shows a very high sensitivity, but only a low specificity. This shortcoming can be mastered by using heterostructures, where graphene is combined with materials exhibiting high analyte selectivities. Herein, this study demonstrates the precise deposition of nanoporous metal-organic frameworks (MOFs) on graphene, yielding bilayers with excellent specificity while the sensitivity remains large. The key for the successful layer-by-layer deposition of the MOF films (SURMOFs) is the use of planar polyaromatic anchors. Then, the MOF pores are loaded with ionic liquid (IL). For functioning sensor devices, the IL@MOF films are grown on graphene field-effect transistors (GFETs). Adding a top-gate electrode yields an ion-gated GFET. Analysis of the transistor characteristics reveals a clear Dirac point at low gate voltages, good on-off ratios, and decent charge mobilities and densities in the graphene channel. The GFET-sensor reveals a strong and selective response. Compared to other ion-gated-FET devices, the IL@MOF material is relatively hard, allowing the manufacturing of ultrathin devices. The new MOF-anchoring strategy offers a novel approach generally applicable for the functionalization of 2D-materials, where MOF/2D-material hetero-bilayers carry a huge potential for a wide variety of applications.     

Water-Surface-Mediated Precise Patterning of Organic Single-Crystalline Films via Double-Blade Coating for High-Performance Organic Transistors

Application-oriented growth of patterned organic semiconductor (OSC) thin films with a single domain is a nonnegotiable requirement for the manufacturing of high-performance organic electronic devices. However, the prevalent selective-wetting patterning method remains a challenge in controlling the density of nucleation events in microscale spaces, resulting in thin films with high grain boundary density and no preferential orientation spherulites. Herein, a simple double-blade-coating printing technique using a combination of wetting-patterned substrates to produce an array of highly crystalline OSC thin films is developed. Specifically, the approach confines the OSC crystallization on a molecular-flat water surface in specific areas, enabling a significant reduction in the number of nuclei. Consequently, patterned 2,7-dioctyl[1]benzothieno[3,2-b] benzothiophene (C₈-BTBT) thin films comprising single-crystal domains are achieved with an exceptionally high yield of 62.5%. The organic field-effect transistor array developed from such patterns of C₈-BTBT single-crystalline films exhibits an excellent average mobility of 11.5 cm² V⁻¹ s⁻¹ which is 12.5-fold higher compared to that of the reference sample fabricated via conventional single-blade coating. It is believed that this approach can be widely applied to other soluble organic materials, thereby opening up opportunities for fabricating multicomponent integrated electronics.     

农林高校电气类专业教学改革与思政探索

在以德为先的教育背景下,高校意识形态问题是人才培养的关键。如何将课程思政的思想以专业知识为载体巧妙渗透到课堂中,是未来高等教育需要思考的重要问题。本文基于农林高校电气类专业实际情况,深入挖掘具有思政元素且特色鲜明的电气专业教学体系,提出面向“三农需求”的“一主线、四段式、八深入”课程体系改革融入构架,并给出以“林区新能源发电技术”为例的课程思政改革方案实例。     

射频溅射法生长ZnO薄膜的参数研究

以ZnO陶瓷为溅射靶材,通入纯氩气,使用射频溅射法在玻璃基片上制备ZnO薄膜,研究了气体压强、基片温度、溅射功率等对薄膜性质的影响。通过XRD及原子力显微镜(AFM)等检测得出制备C轴(002)ZAO薄膜的最佳工艺条件为:溅射压强0.4Pa;溅射功率200W;基片温度300℃。     

纳秒Bessel光束截面光强的分布

由衍射积分理论给出平行光通过轴棱锥后的光场分布表达式,模拟得到Bessel光束截面光强分布图.利用轴棱锥法,以平-抗共振环(ARR)介稳腔Nd:YAG调Q激光器为光源,获得高稳定的纳秒Bessel光脉冲.通过胶片扫描法和激光光斑能量分布的三维可视化方法,获得纳秒Bessel光截面光强的二维及三维能量分布图.实验结果与理论模拟基本吻合.实验结果表明,通过上述方法得到的分布图达到了比DataRay公司的Taper-CamD-UCM-20-15型光束分析仪要高的图像分辨率,是一种记录ps、甚至fs超短光脉冲空间能量分布的有效方法.     

环氧-玻纤布基板材料的薄型化技术

近年,薄型环氧-破纤布基板材料的开发、应用成为一个热门课题。文章对薄型化CCL的产生背景、三大主要应用领域开拓和对它的性能要求,以及对原材料技术新发展的驱动做一讨论。     

Self‐Assembly of Nanostructured,Complex, Multication Films via Spontaneous Phase Separation and Strain‐Driven Ordering

Spontaneous self‐assembly of a multication nanophase in another multication matrix phase is a promising bottom‐up approach to fabricate novel, nanocomposite structures for a range of applications. In an effort to understand the mechanisms for such self‐assembly, complimentary experimental and theoretical studies are reported to first understand and then control or guide the self‐assembly of insulating BaZrO₃ (BZO) nanodots within REBa₂Cu₃O_7–δ (RE = rare earth elements including Y, REBCO) superconducting films. The strain field developed around BZO nanodots embedded in the REBCO matrix is a key driving force dictating the self‐assembly of BZO nanodots along REBCO c‐axis. The size selection and spatial ordering of BZO self‐assembly are simulated using thermodynamic and kinetic models. The BZO self‐assembly is controllable by tuning the interphase strain field. REBCO superconducting films with BZO defect arrays self‐assembled to align in both vertical (REBCO c‐axis) and horizontal (REBCO ab‐planes) directions result in the maximized pinning and J_c performance for all field angles with smaller angular J_c anisotropy. The work has broad implications for the fabrication of controlled self‐assembled nanostructures for a range of applications via strain‐tuning.