提高频谱分析仪测试性能的几种方法

通过分析频谱分析仪基本工作原理和主要用途，结合实际测试工作中的经验，总结了优化频谱分析仪设置、提高频谱分析仪测试性能的几种方法。     

频谱分析仪检定的测量不确定度分析

在频谱分析仪检定过程中,对其测量结果进行不确定度分析是其中必不可少的一项工作。由于频谱分析仪检定项目多,考虑到频谱分析仪主要表征的是频率参量和幅度参量,所以选取频率读数测量和输入衰减器测量进行测量不确定度评定。并以检定HP8563E频谱分析仪为例,分析了影响其测量不确定度的几个因素,同时针对具体的数据进行了详细的分析,能够对从事频谱分析仪检定工作的计量人员提供帮助。     

频谱分析仪自动校准中的问题及解决方式

频谱分析仪用于周期信号或准周期信号的频谱分析,广泛应用于通信、广播等行业,为了确认频谱分析仪的可靠性,每年都需要定期对其校准。频谱分析仪传统的校准方法中问题较多,如:校准方法不统一、校准指令不通用、被校准点不可更改。针对这些问题,本文提出了频谱分析仪自动校准软件解决方式,所设计的自动校准系统可对多品牌、多系列的频谱分析仪做自动校准,自动查找识别仪器、智能校准、生成原始记录和证书、功能可扩展等。该校准系统智能、高效、可靠。     

频谱分析仪的检定及装置的不确定度评定

频谱分析仪是常用的信号分析仪器,本文介绍了频谱分析仪的构成、工作原理,根据频谱分析仪的检定参数设计了频谱分析仪检定装置,并对装置的测量不确定度进行了评定,为频谱分析仪的检定工作不确定度的评定以及新的标准装置的研制提供参考。     

频谱分析仪电平准确度测量值的不确定度评定

本文根据JF0919《测量不确定度评定与表示》的要求,依据JJG 501-2000《频谱分析仪检定规程》对频谱分析仪电平准确度的不确定度进行分析。通过对A、B两类测量不确定度的具体分析,得出工程应用中频谱分析仪电平准确度的扩展不确定度。     

频谱分析仪现行检定规程与校准规范的对比研究

本文对比介绍了JJF1396-2013《频谱分析仪校准规范》与GJB/J 5859-2006《宽频带频谱分析仪检定规程》的检定校准项目、方法及相关要求,为频谱分析仪的检定校准工作开展提供参考借鉴。     

频谱分析仪输入电平测量不确定度评定

本文通过对E4445 A频谱分析仪输入电平测量结果的不确定度的计算和分析,介绍了对频谱分析仪测量结果的不确定度分析与评定方法。     

如何进一步提高频谱分析仪幅度测量准确度

一、优化幅度测量准确度的方法1.测量前先进行自动校准现在的频谱分析仪都有自校程序,这些自校程序能生成误差系数(例如,分辨带宽不同引起的幅度变化),频谱分析仪能利用误差系数修正测量数据。因此,对频谱分析仪实施自校可得到精确的幅度测量,并能在测量过程中自由地改变控制参数。     

JJF1396-2013《频谱分析仪校准规范》的解读

正一、规范修订的背景及目的频谱分析仪的计量技术法规JJG501-1987《频谱分析仪检定规程》最早于1987年发布实施,2000年对其作了重新修订,被JJG501-2000《频谱分析仪检定规程》代替。随着电子测量技术的不断发展,频谱分析仪的频域测量技术不断改进,频率测量范围不断拓宽,测量准确度不断提高,测量功能也不断增多。而原检定规程的频率测量范围只覆盖到26.5GHz,且某些测量方法已无法对新型频谱分析仪实现科学合理的计     

一种新的频谱分析仪测量不确定度评定方法研究

由于频谱分析仪检定参数众多,传统的不确定度评定方法是对近二十项检定项目逐一进行分析,评定过程十分繁琐。为解决频谱分析仪检定结果不确定度评定项目多、评定过程复杂的问题,在深入研究各检定项目具体表征的是何参量的基础上,结合检定工作实际,提出将频谱分析仪不确定度评定项目归纳为频率、功率、相对电平等三个参量,对频谱分析仪测量不确定度进行评定的方法,并给出了详细的评定过程。     

Mechanochemical fabrication of C (matrix) + Cu + Si + W + Mo nanocomposites

Using magnesiothermic reduction of WO₃, MoO₃, SiO₂, and CuO through mechanochemical activation, we prepared high-purity (∼99.3%) nanopowders with a particle size from 9 to 350 nm for the fabrication of functional materials and nanocomposite systems for anode electrodes of lithium ion (polymeric) batteries.     

新西兰JAG CREATIVE:品牌、营销与推广

为这个真实世界进行品牌与平面设计创作就是新西兰Jag Creative品牌设计公司的热情。作为一个岛国,新西兰的企业在创新与创造性方面有着令人惊叹的杰出表现。     

高密度发光材料γ-Bi2WO6:Pr3+的发光性质研究

研究了用固相法制备的高密度发光材料γ-Bi2WO6Pr3+的结构、光致发光光谱、激发谱和γ-Bi2WO6的漫反射谱.由实验测得它的晶格参数为a=5.45A,b=16.42A,c=5.43A,密度Dx=9.53g/cm3.它的光致发光光谱主发射峰位于600、608、611、629nm,分别来自于pr3+的1D2→3H4、3P0→3H5、3P0→3H6、3P0→3F2跃迁的发射.其激发谱由位于约225～430nm范围内、最大值约在372nm的主激发带和450nm的激发峰组成;主激发带来自于基质,可能是基质的带间吸收、W-O间电荷迁移吸收和缺陷能级的吸收;450nm的激发峰来自于pr3+的3H4→3P2跃迁吸收.BWOPr3+的最佳掺杂浓度为0.8mol%左右.     

(Sr2+,Bi3+,Si4+,Ta5+)掺杂的TiO2压敏陶瓷中Ta5+的研究

研究Ta2 O5对 (Sr,Bi,Si,Ta)掺杂的TiO2 基压敏陶瓷压敏特性及电容特性的影响 ,发现按配方TiO2 0 .3%(SrCO3 Bi2 O3 SiO2 ) 0 .1 %Ta2 O5配制的样品具有最低压敏电压 (E1 0mA =1 .2V·mm- 1 )、最大相对介电常数 (εra=2 .0 0 2× 1 0 5)及较小非线性系数 (α =2 .6 )。考虑到材料的低压敏电压和大介电常数的要求 ,Ta2 O5最佳掺杂量在 0 .0 85mol%与 0 .1mol%之间。     

Electrical characterization of Si+ and Si+/P+ implanted N+P+In0.53Ga0.47As junctions

In this communication, we present I–V and admittance spectroscopy measurements of shallow n⁺p junctions into p-InGaAs made by Si⁺ implantation, including a complete study of the conduction mechanisms as a function of temperature. The effect of P⁺ co-implantation is also analysed. The I–V characteristics of both junctions show that recombination in the space-charge zone is the dominant transport mechanism in forward bias, with ideality factors around 1.5 at 300 K that increase with decreasing temperature of measurement. Activation energies of the reverse saturation current are obtained at room temperature, being 0.5 eV and 0.4 eV for Si⁺ and Si⁺P⁺ implanted diodes, respectively, indicating that recombination currents occur through a near midgap center. Reverse current–voltage measurements show a higher conduction in the P⁺ co-implanted junction due to a higher concentration of traps. In both types of junctions, the reverse characteristics can be fitted to a thermally-activated trap-assisted tunneling mechanism at low bias, involving traps at 0.41 eV and 0.44 eV for Si⁺ and P⁺ co-implanted junctions, respectively, whereas different trap-assisted tunneling processes dominate at medium and high bias. The small signal analysis show a clear difference between the two types of junctions. The use of Kramers–Kronig transforms on the admittance spectroscopy data reveals the presence of a defect level at 0.35 eV in both types of junctions, probably assigned to Zn, the native acceptor present in the p-InGaAs. Another trap level at 0.30 eV is detected at the P⁺ co-implanted junctions, not appearing in the Si doped junctions, which could probably be due to damage produced by the co-implantation.     

（Sr^2＋，Bia^3＋，Si^4＋，Ta^5＋）掺杂的TiO2压敏陶瓷中Ta^5＋的研究

研究Ta2O5对(Sr,Bi,Si,Ta)掺杂的TiO2基压敏陶瓷压敏特性及电容特性的影响,发现按配方TiO2+0.3%(SrCO3+Bi2O3+SiO2)+0.1%Ta2O5配制的样品具有最低压敏电压(E10mA=1.2V·mm-1)、最大相对介电常数(εra=2.002×105)及较小非线性系数(a=2.6).考虑到材料的低压敏电压和大介电常数的要求,Ta2 O5最佳掺杂量在0.085mol%与0.1mol%之间.     

Measurement of solubility and density of water + lithium bromide + lithium chloride and water + lithium bromide + sodium formate systems

Solubility of aqueous solutions containing lithium bromide + lithium chloride and lithium bromide + sodium formate were measured (LiBr/NaHCO₂ = 2 and LiBr/LiCl = 2 by mass ratio) at different temperatures. Visual polythermal method was used in the temperature range of (283.15–340.15) K and mass fraction range of (0.4–0.8). Also density of mentioned systems was reported in the temperature range of (288.15–333.15) K. Each set of experimental measurements were correlated using least-square regression as a function of temperature. Our results indicate that solubility of LiBr + LiCl is higher than LiBr and its density is lower than density of aqueous solution of LiBr.     

Phase Composition of the Products of Fe Oxidation in Fe + C + NaCl + H2O + O2 Exothermic Mixtures

Using thermodynamic analysis of the Fe–C–NaCl–H₂O–O₂ system and experimental studies (x-ray diffraction and Mössbauer spectroscopy) of exothermic mixtures containing Fe metal, activated carbon, water, and NaCl, we identified the state of Fe and determined the phase composition of the reaction products at different stages of oxidation with atmospheric oxygen. The calculation and experimental results are in reasonable agreement. Under the conditions of restricted access for air, the main oxidation product is magnetite, Fe₃O₄. Free access for air leads to the formation of hydrous ferric oxide, Fe₂O₃ · nH₂O. The most stable phase under the conditions of interest is goethite, Fe₂O₃ · H₂O (-FeOOH). Storage of incompletely oxidized samples away from air for 7–14 days leads to partial reduction of iron(III) oxide phases to Fe₃O₄ and -Fe.     

Solubilities, Vapor Pressures, and Heat Capacities of the Water + Lithium Bromide + Lithium Nitrate + Lithium Iodide + Lithium Chloride System

The optimum mole ratio of lithium salts in the H₂O + LiBr + LiNO₃ + LiI + LiCl system was experimentally determined to be LiBr : LiNO₃ : LiI : LiCl = 5 : 1 : 1 : 2. The solubilities were measured at temperatures from 252.02 to 336.75 K. Regression equations on the solubility data were obtained with a least-squares method. Average absolute deviations of the calculated values from the experimental data were 0.15% at temperatures <285.18 K and 0.05% at temperatures 285.18 K. The vapor pressures were measured at concentrations ranging from 50.0 to 70.0 mass% and at temperatures from 330.13 to 434.88 K. The experimental data were correlated with an Antoine-type equation, and the average absolute deviation of the calculated values from the experimental data was 2.25%. The heat capacities were measured at concentrations from 50.0 to 65.0 mass% and temperatures from 298.15 to 328.15 K. The average absolute deviation of the values calculated by the regression equation from the experimental data was 0.24%.     

Ionic conductivity of potassium antimonate tungstates with partial Na+ or Li+ substitution for K+

We have studied the formation of monovalent metal antimonate tungstates by solid-state reactions in the xM₂CO₃ · (y ? x)K₂CO₃ · ySb₂O₃ · 2(2 ? y)WO₃ (M = Na, Li; 0 ≤ x ≤ y; 1.0 ≤ y ≤ 2.0) systems and identified the stability regions of pyrochlore phases at a temperature of 1123 K in the KSbO₃-WO₃-MSbO₃ (M = Na, Li) composition triangles. A model has been proposed for the ion distribution over the sites of the pyrochlore structure (sp. gr. Fd3m). The conductivity of the monovalent metal antimonate tungstates has been measured in the temperature range 500–1000 K, and a relationship between their ionic conductivity and structure has been established.