A Noninvasive Resonance-Based Method for Moisture Content Evaluation Through Microstrip Antennas

Several techniques for measuring the moisture levels of materials, particularly in the soil science area, are available. Nevertheless, the state of the art is rather lacking in moisture-sensing methods that are both inexpensive and noninvasive. The time-domain reflectometry (TDR)-based method, despite being a well-established low-cost technique for sensing moisture content, is intrinsically invasive due to the configuration of the probes that are commonly used. These considerations motivated the authors to investigate the adoption of simple inexpensive microstrip antennas as sensing elements for TDR-based moisture content measurements. For this purpose, the water content of the monitored material is sensed through the changes in the reflection scattering parameter S ₁₁(f) of the antenna. In particular, the change in the resonant frequency of the antenna, which is evaluated through an appropriate processing of the TDR waveforms, is correlated with the water content of the material under investigation. The ultimate goal is to assess a sensing method that can be implemented for inexpensive real-time noninvasive monitoring applications.     

一种利用S参数测量平衡RFID标签天线阻抗的优化方法

针对测量平衡RFID标签天线阻抗的准确性问题,提出了一种利用s参数测量的优化方法。该方法将平衡RFID标签天线等效为双端口网络,通过联合使用端口短路、开路延伸方法测量S参数,根据拐点选取最邻近数据并进行区间的数据拟合,从而计算出天线阻抗。首先 h1 进行了测量理论分析．然后设计了实物测量场景（915MHz频段的RFID天线）,并将该优化方法与传统的Bahm方法、无延伸单端口方法、延伸单端口方法进行了对比。结果表明,在工作频段内,该优化方法所测的标签天线的阻抗实部,虚部与仿真结果基本一致,比传统的Balun2及单端口等测摄方法准确;在工作频段外,所测阻抗实部仍然与仿真结果接近,尽管阻抗虚部与仿真结果存在一定的偏差。     

Development and Characterization of a 96-Well Exposure System for Safety Assessment of Nanomaterials

In this study, a 96-well exposure system for safety assessment of nanomaterials is developed and characterized using an air–liquid interface lung epithelial model. This system is designed for sequential nebulization. Distribution studies verify the reproducible distribution over all 96 wells, with lower insert-to-insert variability compared to non-sequential application. With a first set of chemicals (TritonX), drugs (Bortezomib), and nanomaterials (silver nanoparticles and (non-)fluorescent crystalline nanocellulose), sequential exposure studies are performed with human lung epithelial cells followed by quantification of the deposited mass and of cell viability. The developed exposure system offers for the first time the possibility of exposing an air–liquid interface model in a 96-well format, resulting in high-throughput rates, combined with the feature for sequential dosing. This exposure system allows the possibility of creating dose-response curves resulting in the generation of more reliable cell-based assay data for many types of applications, such as safety analysis. In addition to chemicals and drugs, nanomaterials with spherical shapes, but also morphologically more complex nanostructures can be exposed sequentially with high efficiency. This allows new perspectives on in vivo-like and animal-free approaches for chemical and pharmaceutical safety assessment, in line with the 3R principle of replacing and reducing animal experiments.     

装备贮存可靠性评定方法

对军用装备的贮存可靠性指标予以统计指标，对装备系统常见的有性能参数要求的机械、电子整机，有强度要求的结构件整机和一次性使用产品等三大类型军用装备的贮存可靠性给出定量评定的模型。     

Method for the Characterization of Extreme-Ultraviolet Photoresist Outgassing

Outgassing from photoresists illuminated by extreme ultraviolet radiation can lead to degradation of the very expensive multilayer-coated optics in an extreme ultraviolet stepper. Reliable quantification of the various organic molecules outgassed by photoresists has been a challenging goal. We have designed a compact system for this measurement. In the first step, the total number of molecules emitted by the photoresist is measured using a pressure-rise method in a closed vacuum chamber, with the pressure measured by mechanical means using a capacitance displacement gauge. To provide identification and relative abundances, the outgassed molecules are then collected in an evacuated trap cooled by liquid nitrogen for subsequent analysis by gas chromatography with mass spectrometry. We will discuss the design and performance of the system.     

一种化学危害风险评估方法的探讨

本文阐述了目前我国风险评估工作中的关键技术问题,并以"专家评分法"与"风险矩阵法"为核心,提出了一种化学危害风险评估方法.     

Dipole Approximation for Electrically Small Loop Antennas

Measurement Techniques - An elementary magnetic emitter is considered as an approximation for the variable magnetic field of an electrically small radiating loop antenna. The frequency limits for...     

一种新的符合性评定方法设计与分析

符合性评定是依据系统规则来评判被测量满足技术指标要求的程度.但在实际测试中存在测量结果及其测量不确定度区间非常接近甚至包含了指标"规范限"的情况,使得根据测量结果信息无法做出决策评定.为此本文提出新的符合性评定"两步法",给出了基于测量值及其测量不确定度的符合性评定规则,解决通常符合性评定中一步测试往往无法得出确切结果...     

Flexible and Stretchable Antennas for Biointegrated Electronics

Combined advances in material science, mechanical engineering, and electrical engineering form the foundations of thin, soft electronic/optoelectronic platforms that have unique capabilities in wireless monitoring and control of various biological processes in cells, tissues, and organs. Miniaturized, stretchable antennas represent an essential link between such devices and external systems for control, power delivery, data processing, and/or communication. Applications typically involve a demanding set of considerations in performance, size, and stretchability. Some of the most effective strategies rely on unusual materials such as liquid metals, nanowires, and woven textiles or on optimally configured 2D/3D structures such as serpentines and helical coils of conventional materials. In the best cases, the performance metrics of small, stretchable, radio frequency (RF) antennas realized using these strategies compare favorably to those of traditional devices. Examples range from dipole, monopole, and patch antennas for far-field RF operation, to magnetic loop antennas for near-field communication (NFC), where the key parameters include operating frequency, Q factor, radiation pattern, and reflection coefficient S₁₁ across a range of mechanical deformations and cyclic loads. Despite significant progress over the last several years, many challenges and associated research opportunities remain in the development of high-efficiency antennas for biointegrated electronic/optoelectronic systems.     

无参考混合失真图像质量评价方法

目的为了解决图像在实际处理过程中产生混合失真的情况,研究无参考混合失真图像质量评价方法。方法首先利用空域-频域信息熵和奇异值建立无参考混合失真图像失真类型判别模型,然后再根据不同的混合失真类型,分别提取多维空间统计特征、奇异值改变量和空域-频域信息熵等3种不同的图像信息特征,建立无参考混合失真图像质量评价模型,并选取最佳无参考图像质量评价(NR-IQA)模型得到分数。结果该方法能100%判别混合失真类型,对于模糊噪声、模糊压缩混合失真在LIVE混合失真图像数据库(LIVEMD)上的斯皮尔曼等级相关系数(SROCC)最高分别能达到0.9874和0.9916,具有很好的主观一致性。结论实验结果表明,该无参考混合失真图像质量评价方法与人眼视觉感知具有很好的主观一致性。     

A Method for Instant Assessment and Active Learning

Abstract A method that provides tremendous benefits to both instructors and students is described in this paper. The method is based on asking a multiple choice question after every 10 to 20 minutes of a lecture and getting responses from all the students. The students respond by raising a card which displays the letter corresponding to their choice of answer. The method is easy to implement in any traditional lecture setting. It provides instant assessment of student learning and lets an instructor take corrective measure, if necessary, in the same class period. The method allows all the students in a class to actively participate, evaluate their own performance, and reflect upon what they have learned. The method works well either in a small or a large class and it typically creates an atmosphere of fun and learning in the classroom.     

A Method for Improving Multivariate Measurement Systems Assessment

Multivariate measurement systems analysis (MSA) is usually performed by designing suitable gauge repeatability and reproducibility (R&R) experiments, ignoring available data generated by the measurement system while used for inspection or process control. This article proposes an approach that, by using the data that are routinely available from the regular operation of the instrument, allows the measurement instrument's current precision to be compared against a benchmark. The proposed method may be appropriately used in an integrated and coordinated manner with the usual multivariate gauge study in the sense that it can be used to assess the stability or a possible deterioration in the precision of the measurement instrument while operational. Therefore, the complementary use of the proposed approach and the traditional multivariate gauge R&R studies can be a useful strategy for improving the overall quality of multivariate measurement systems. Furthermore, because it can be implemented at almost no additional cost, it may be effective in reducing the costs of a multivariate MSA performed with a certain frequency. Copyright © 2014 John Wiley & Sons, Ltd.     

Close-Packed Silicon Lens Antennas for Millimeter-Wave MKID Camera

We have been developing a large-format millimeter-wave camera based on lens-antenna-coupled microwave kinetic inductance detectors (MKIDs) for a planned telescope at Dome Fuji (3810 m a.s.l.), Antarctica. Optical coupling to the MKID incorporates double-slot antennas and a silicon lens array. To realize a large-format camera ( \(>\) 10,000 pixels), a highly integrated small-diameter lens array and fast optics are required. Lens diameters of 1.2, 2, and 3 times the target wavelength are investigated for the main beam symmetry, side-lobe level, cross-polarization level, and bandwidth, considering the effects of the surrounding lenses. In this study, we present the simulated beam pattern profiles of close-packed lens antenna and the effect of misalignment between the silicon lens and double-slot antenna. We also show the evaluations of the developed 721-pixel close-packed silicon lens array.     

Calibration Method and Uncertainty Assessment of a High-Temperature GHP Apparatus

In this research, a calibration method of a high-temperature guarded hot plate (GHP) apparatus was proposed in order to improve the measurement accuracy of thermal conductivity. The measurement uncertainties of this GHP apparatus were assessed to validate the reliability of this calibration method. The temperature difference across the guarded gap was set as the bias value to eliminate the heat exchange over the guarded gap. The effects of the thermal expansion and pressure of the apparatus on thickness were investigated to revise the measurement results of in-situ thickness and meter area, respectively. The assessed uncertainty indicated that the related expanded uncertainty approximately increased with the increase in testing temperature and the calibration method should be valid in the temperature range. The contribution of each factor on the combined uncertainty showed that the temperature distribution in plane direction was the main factor in influencing the measurement of thermal conductivity.     

区域水资源可持续利用评价理论模型与方法

文章在论述区域水资源可持续利用与水资源承载能力关系的前提下,提出了区域水资源可持续利用评价的模糊模式识别理论、模型和方法。应用所建立的模型对汉中盆地水资源可持续利用的程度进行了评价,应用实例表明,理论模型严谨,方法简洁,评价结果合理可行。此方法也可用于区域社会经济可持续发展等的评价。     

Near-Field Gain Correction for Transmission between Horn Antennas

When the gain of a horn antenna is to be measured from the power transmission loss between it and a standard horn, the Friis transmission formula must be corrected if the horn separation is not considerably greater than 2d2/?. Expressions for the correction between a pyramidal horn and a conical horn, and between dissimilar pyramidal horns, are presented with sample results. A method of applying these corrections to minimize the errors in the horn gain measurements is described.     

视频质量评价中时域信息检测的新方法

针对视频质量评测中时域信息的检测方法,本文提出了新的计算方法.该方法根据 ANSI TI.801.03-1996和ITU-TRecommendationP.910时域信息(TI)的概念定义和方法推荐,采用先对时域梯度图求直方图,再在所求直方图的基础上进行统计计算的方式,克服了直接进行时域梯度RMS计算带来的乘法运算量与画面像素数成正比从而导致耗时较多的缺陷.实验结果表明,采用本改进方式的乘法运算量仅取决于直方图的灰度级,而与具体像素数无关,在同等条件下的平均计算效率可提高约三倍,且对时域信息的检测效果与推荐方法相仿.该方法实现简单,易于集成,在视频质量评测应用中具有较好的推广价值.