用于焦平面测试系统的高效高精度数据采集方法与实现

通过分析焦平面测试中各种性能参数对数据要求的特点,提出了一种区别于传统的高效数据采集方法,并采用ADI最新发布的16位高性能ADC,设计了基于该方法的高效高精度采集系统.通过内嵌的“RMS硬件算法”和外部SRAM的特殊组合,在兼容传统测试系统的同时,大大提高了系统的测试效率.经碲镉汞(HgCdTe)型640×512(1...     

基于C8051F340单片机的红外温度监测系统的设计

为实现对装药过程中实时温度的检测,设计了一套C8051F340单片机与时分复用技术进行数据采集和通信的多通道温度采集系统。实验验证了CPLD在进行分时控制时具有计时准确,门选电路设计方便,集成度高的优点,同时结合Silicon Laboratories公司提供的USBXpress开发工具使得单片机与计算机的USB通信实现变得极为简便。     

Thermal stability and transport studies of (100 − 2x)TeO2-xAg2O-xWO3 (7.5 ≤ x ≤ 30) glass system

Differential scanning calorimetry (DSC), infrared (IR) and direct current (DC) conductivity studies have been carried out on (100 − 2x)TeO₂-xAg₂O-xWO₃ (7.5 ≤ x ≤ 30) glass system. The IR studies show that the structure of glass network consists of [TeO₄], [TeO₃]/[TeO₃₊₁], [WO₄] units. Thermal properties such as the glass transition (T_g), onset crystallization (T_o), thermal stability (ΔT), glass transition width (ΔT_g), heat capacities in the glassy and liquid state (C_pg and C_pl), heat capacity change (ΔC_p) and ratios C_pl/C_pg of the glass systems were calculated. The highest thermal stability (237 °C) obtained in 55TeO₂-22.5Ag₂O-22.5WO₃ glass suggests that this new glass may be a potentially useful candidate material host for rare earth doped optical fibers. The DC conductivity of glasses was measured in temperature region 27-260 °C, the activation energy (E_act) values varied from 1.393 to 0.272 eV and for the temperature interval 170-260 °C, the values of conductivity (σ) of glasses varied from 8.79 × 10⁻⁹ to 1.47 × 10⁻⁶ S cm⁻¹.     

Electrical, optical and vibrational characteristics of nano structured yttrium barium stannous oxide synthesized through a modified combustion method

A single step combustion process for the preparation of nanoparticles of yttrium barium stannous oxide is reported in this paper. The structure, phase purity and particulate properties of the as prepared nano YBa₂SnO_5.5 powder were examined by X-ray diffraction and transmission electron microscopy. The as prepared powder obtained itself is phase pure and possess cubic structure with lattice constant 8.240 Å. The particle size of the as prepared sample from Transmission Electron Microscopy analysis is in the range of ∼15 nm. Vibrational studies carried out on the as prepared powder also confirm the cubic structure of the as prepared sample. The thermal stability of the nano particle is analyzed by thermo gravimetric and differential thermal analysis. The material is a semiconductor with excellent luminescent properties. Chemical compatibility of the sample with YBCO is analyzed. The YBCO-YBa₂SnO_5.5 composite showed T_c(0) at 92 K.     

Synthesis and characterization of new composites: PANI/Na-AlSBA-3 and PANI/Na-AlSBA-16

The new aluminosilicate materials (Na-AlSBA-3 and Na-AlSBA-16) were synthesized for application in the preparation of composites. Silica mesoporous materials were obtained following the sol-gel method and post-synthesis alumination. These methods were effective for the synthesis of SBA-3 and SBA-16, showing XRD patterns and other characteristics in agreement with the literature.Aniline-saturated hosts were prepared by adsorption of aniline (exposed to the equilibrium vapors from liquid aniline) into the mesoporous materials. Polyaniline/Na-AlSBA-3 (PANI-3) and polyaniline/Na-AlSBA-16 (PANI-16) composites have been synthesized by an in situ polymerization of aniline-saturated hosts. TG, FTIR, XRD, SEM and TEM were used to characterize the resulting composites. These studies show that PANI is generated inside the channel of the hosts. PANI-16 has an amount of emeraldine salt higher than PANI-3 composite. The electrical conductivity measurements confirmed that PANI and mesoporous materials were true hybrid nanocomposites. The conductive properties of these composites were compared with those of other composites (polyaniline/Na-AlMCM-41 and polyaniline/Na-AlSBA-15) reported.     

Crack Tip Opening Angle Measurement Methods and Crack Tunnelling in 2024‐T351 Aluminium Alloy

Abstract: The crack tip opening angle (CTOA) fracture criterion is one of the most promising fracture criterion used to characterise the stable tearing process in metallic materials. Traditional methods used for the experimental characterisation of the CTOA involve accurate identification of the crack tip at each tearing event. Recently alternative methods have been proposed that reduce the necessity of accurately defining the current crack and rely more on the shape of the crack flanks to define the CTOA. In addition, these methods define an ‘apparent crack tip’, which may be different from the actual surface crack tip and may provide insight into the amount of crack‐front tunnelling that is occurring. In the current research, compact tension specimens fabricated from 6.35 mm thick 2024‐T351 aluminium alloy plate were evaluated to investigate different CTOA measurement methods and their potential for estimating crack‐front tunnelling. In addition to characterizing the CTOA, fatigue marker bands were employed to map the evolution of crack‐front tunnelling. The experimental critical CTOA values obtained from the alternative methods were noticeably lower than that obtained from the traditional approach and showed noticeably more scatter. When compared to the experimentally obtained marker bands, the alternative methods indicated limited potential for predicting crack‐front tunnelling.     

Evaluation of Low‐Cost Separators for Increased Power Generation in Single Chamber Microbial Fuel Cells with Membrane Electrode Assembly

We compared novel size‐selective separators, namely the textile fabrics of polyphenylene sulfide (PPS) and sulfonated polyphenylene sulfide (S‐PPS), and the nonwoven fabrics of polypropylene80 (PP 80) and PP 100, with commonly used ion exchange separators (Nafion 117 and cation exchange membane‐7000; CMI‐7000) in terms of power generation, oxygen diffusion, and biofilm formation in a single chamber microbial fuel cell. Size‐selective separators exhibited more power generation than ion selective separators. MFC operation with size‐selective separators generated power output ranging 0.407 to 0.591 V (1000 Ω), whereas with Nafion it was 0.272 V. In polarization analysis, S‐PPS resulted in the highest power density of 190 mW/m², whereas it was 24 mW/m² with Nafion‐117. Size selective separators showed similar or higher proton conductivity than Nafion 117. Oxygen mass transfer coefficients of size‐selective separators (K_O = 3.7 ∼ 7.5 × 10⁻⁵) were lower or similar to Nafion (K_O = 7.5 × 10⁻⁵). Fourier‐transform infrared spectroscopy and scanning electron microscopy analysis revealed that all separators (PP80, S‐PPS, and Nafion) contained proteins or carbon chain compounds after 300‐day operation, and however, Nafion 117 seems to be more susceptible to biofouling than the other separators.     

一种红外图像增强的新方法

结合红外图像的成像特点,采用各种图像,增强算法对红外图像进行处理,分别实现了对比度提高、抑制噪声及增强边缘的效果。在此基础上,根据不同算法可实现的效果,提出了一种可将几种算法的优点融合为一体的混合算法。这种算法进一步提高了图像的视觉效果。     

Gasmet便携式傅里叶变换红外气体分析仪及其在环境应急监测中的应用

本文主要介绍了芬兰Gasmet Technologies Oy公司生产的GASMET FTIR Dx4020便携式傅里叶变换红外气体分析仪。包括它的工作原理和多组分同时定性、定量测定原理,以及随机携带的Calcmet中文智能软件功能、仪器内部配置。出厂进行一次初始标定后,无需再次标定等性能特点,最后从仪器的多组分定性、现场定量、连续监测三个特点列举了本仪器在环境应急监测中的应用事例     

Using equidistant vector-based hysteresis current regulators in DFIG wind generation systems

This paper proposes a novel equidistant vector-based hysteresis current regulator (VBHCR) in the rotor-side converter (RSC) of DFIG-based wind generation systems. The Γ-form equivalent circuit is used for the machine modelling, with the discrete formulation of the RSC output voltage. The overall vector control scheme is then explored and the control structure of the proposed equidistant VBHCR is presented. When compared to the commonly used PI current regulators, the proposed VBHCR exhibits several advantages such as very fast transient response, simple hardware implementation, satisfactory steady-state performance, and intrinsic robustness to machine parameters variations. Moreover, fixed hysteresis bands are replaced with equidistant bands in order to limit the instantaneous variations of the switching frequency and reduce the maximum switching frequency of the RSC. Detailed simulation studies are carried out for a 1.5 MW DFIG-based wind generator to examine the operation of the proposed current regulator under various operating conditions and demonstrate its superiority over the standard PI current regulator.