A Terahertz Video Camera Patch Sheet with an Adjustable Design based on Self-Aligned, 2D,Suspended Sensor Array Patterning

Terahertz (THz) imaging is expected to become powerful tools for non-destructive inspections. To ensure the practical use of THz non-destructive monitoring, versatile THz imagers with adjustable designs that can eliminate the complexities and the bulkiness of the device are urgently required. Herein, a self-aligned filtration process for a 2D, free-standing carbon nanotube film array and its application to a THz video camera patch are reported. The presented techniques enable a) to freely design the camera size, sensor array pattern, and suspended shape according to its applications, b) to cut the camera patch into desired shapes, and c) to attach them to the objects that are intended to be measured. Real-time, non-destructive monitoring of various infrastructures is demonstrated. These results indicate that it can function regardless of restrictions, such as the shapes and locations of the measurement samples, thus providing a strong possibility for use in future non-destructive sensor networks.     

透明红外硫系薄膜非均匀性检测及影响因素

薄膜非均匀性的无损检测对于制备大面积高质量的红外透明薄膜尤为重要。针对红外薄膜光学均匀性难以获取的困难,提出了一种同时获得单层透明红外薄膜厚度和折射率均匀性的无损检测方法。实验上,通过磁控溅射法在二氧化硅衬底上制备了厚度约1.4μm红外透明Ge-Sb-Se硫系薄膜,然后在该薄膜上标定出36个80μm×80μm区域,利用显微傅里叶红外光谱仪测得该36个区域的透射谱,通过分段滤波的方法滤除背景噪声,运用改进的Swanepoel方法计算得到了薄膜每一个区域的厚度和折射率,进而精确获得该薄膜的厚度和折射率均匀性,结果表明精度优于0.5%。     

Dynamic thermal tomography: Recent improvements and applications

The concept of “dynamic thermal tomography” (DTT) was suggested in the 1980s. At that time, there was a wave of interest in the tomographic analysis of materials by active thermal nondestructive testing (TNDT). Unlike particles and quanta of electromagnetic radiation, thermal energy propagates in solids by diffusion. Therefore, a purely geometrical approach, that is characteristic of computed X-ray tomography, is replaced in DTT with the analysis of the evolution of temperature versus time. DTT is based on the fact that, in one-sided TNDT, deeper material layers are characterized by longer time delays of the thermal response. The DTT algorithm is relatively stable when used in the inspection of certain materials. Thermal waves experience damping by amplitude and retardation in time. This limits the detection depth and produces certain artifacts that can be suppressed by thresholding maxigrams. DTT can also be considered as a specific way of data presentation that has proven to be useful in many practical cases, including surface and volumetric thermal stimulation of both metals and non-metals. Thermal tomograms appear similar to binary maps of defects, thus enabling more reliable defect detection in comparison to conventional IR thermograms. In this paper, a “reference-free” approach to DTT is proposed being based on some mathematical manipulations with a front-surface temperature response. Also, the possibility of using the DTT principles for processing the results of ultrasonic infrared thermography is demonstrated.     

Influence of physical and biological variability and solution methods in fruit and vegetable quality nondestructive inspection by using imaging and near-infrared spectroscopy techniques: A review

Over the past decades, imaging and spectroscopy techniques have been rapidly developing and widely applied in nondestructive fruit and vegetable quality assessment. The physical properties (including size, shape, color, position, and temperature) and biological properties (including cultivar, season, maturity level and geographical origin) of fruits and vegetables vary from one to another. A great variety of physical and biological properties of agricultural products influence the optical propagation properties and interaction behaviors with incident light, thus decreasing the quality inspection accuracy. Many attempts have been made in image correction and spectral compensation methods to improve the inspection accuracy. This paper gives a detailed summary about influence of physical and biological variability, as well as the correction and compensation methods for eliminating or reducing the effects in fruit and vegetable quality nondestructive inspection by using imaging and spectroscopy techniques. The advantages and disadvantages of the solution methods are discussed and summarized. Additionally, the future challenges and potential trends are also reported.     

里底水电站混凝土强度与波速线性关系研究及应用

混凝土工程是电站枢纽工程最重要的组成部分之一,是工程安全的基础和保障,确保混凝土实体质量、杜绝混凝土质量缺陷是电站安全稳定运行的基本保证。随着声波检测技术水平的提高,并已在大坝混凝土工程中得到广泛应用。通过大量混凝土实测抗压强度和声波波速值对比试验的数理统计分析,建立工程专用测强曲线,能有效提高混凝土抗压强度推算值的准确性,较真实地反映混凝土实体质量水平。     

锤击瞬态反应技术在混凝土结构检测中的应用

通过实际工程应用介绍一种混凝土无损检测技术———锤击瞬态反应技术的原理、分析方法以及应 用。该项技术可用于非桩混凝土结构的无损检测,特别是对大面积结构构件进行快速内部探伤。实践证明该 检测方法操作简单,数据容易获取,检测速度快。     

“超声法”与“拔出法”综合检测结构混凝土的质量

混凝土作为目前最重要的结构工程材料之一,其质量直接关系到结构的安全。目前正在研究的结构混凝土质量检测方法有很多,但超声-拔出综合法却常被研究者所忽视。该文从超声法和拔出法结合的可行性和优越性两方面进行了论述,并对其如何结合进行了阐述,认为超声-拔出综合法是一种很值得推广的无损检测方法。     

混凝土密实度的雷达检测方法

混凝土的密实度是混凝土耐久性及抗渗性的一个重要指标.由于探地雷达检测具有无损、检测速度快、扫描面积大、效率高等优点,故作者尝试用探地雷达对混凝土的密实度进行检测.针对三种不同外观质量的混凝土路面,对其密实度进行了雷达扫描检测,发现雷达图像有明显差别.并利用渗水性检测仪,对这些路面的抗渗性作了现场测试.结果表明,两种方法的结论是一致的,这表明探地雷达对混凝土的密实度检测,是一种可行的方法.     

地质雷达原理及其在隧道超前预报中的应用

结合使用瑞典RAMAC/GPR地质雷达的实例,介绍了地质雷达的工作原理及其在隧道超前预报中的应用和技巧,并对地质雷达探测技术的应用前景进行了展望,以推广地质雷达探测技术。     

混凝土结构工程无损检测技术的发展动态

本文系统介绍了混凝土结构工程无损检测技术的应用现状,并探讨了混凝土结构无损检测技术的发展趋势。