Comparison of the Visual Performance of Deaf and Hearing Children and Adults in a Detection Task

Visual signal detection psychophysical experiments were done with hearing and deaf subjects, children and adults. Our participants were carefully selected in order to constitute samples of observers as homogeneous as possible. Criteria for selection included consistency as observers (determined by means of preliminary experiments) and age. Our experiments were done under the Two-Alternative-Forced Choice paradigm, using images with Gaussian noise of known energy as background and signals of predetermined energies. Our results suggest that the visual capabilities of deaf and hearing children are practically the same, while deaf adults, when compared to hearing adults, consistently showed higher performances, which tended to become significant as the signal energy was increased.     

接收机工作特性曲线在红外成像系统检测性能评估中的应用

提出了一种红外弱小目标检测算法性能评估的方法。该方法通过假设的数学模型给出了评价指标的理论推导过程,得到了虚警概率与检测门限,检测概率与信噪比之间的关系,绘出了接收机工作特性（ROC）曲线。同时,给出了在目标与背景分布函数未知的情况下,利用红外图像序列绘出ROC曲线来评估算法的检测性能。利用该方法得到了四种典型的弱小目标检测算法的ROC曲线,比较了四种算法的检测性能。     

基于鲁棒M估计和Mean Shift聚类的动态背景下运动目标检测

针对动态背景下运动目标的检测问题,提出了一种基于鲁棒M估计和Mean Shift聚类的目标检测新方法。首先,在考虑全局光照变化的情况下,构建鲁棒M估计器估计全局运动,以实现最小化相邻2帧图像中所有像素亮度的绝对残差和,根据M估计得到像素点权值,提取出代表局部运动信息的离群点;在离群点中均匀抽取网格点,然后利用Mean Shift聚类算法实现不同运动点的分割;根据聚类的结果生成凸包,准确分割出运动目标区域。实验结果表明,该方法能检测出动态背景下的多个运动目标区域,多目标检测准确度到达95%以上,并且只需两帧图像就可以准确检测并锁定运动目标,满足实时处理的要求,具有一定的工程意义.     

The Flow Patterns and Wall Stresses in a Louvered‐Wall Moving Granular Filter Bed of Quartz Sand

The flow patterns and wall stresses in a two‐dimensional louvered moving granular filter bed of quartz sand were investigated. The flow pattern histories of granular solids in the filter bed were recorded using a digital camcorder and a pressure gauge for simultaneously measuring the normal stresses as well as shear stresses of the granular solids. The static wall stress distributions produced by the granular solids were measured, and agreed with a theoretical prediction formed using the differential slice and Runge‐Kutta (order four) methods. The variations in the dynamic wall stresses with time in a moving granular filter bed were obtained and the effect of the louver angle upon the flow patterns and wall stresses was also investigated. Employing the results obtained by stress measurements and image processing, the wall pressure pulsation phenomena in a moving granular filter bed may be further understood. The results reported here provide fundamental information for the design of moving granular filter beds to act as high‐temperature flue gas cleanup filters.     

Acoustic and thermal field investigation of low-cost dwellings, a case study in Brazil

The present paper presents acoustic and thermal performance evaluations carried out in low-cost houses located at the Vila Tecnológica de Curitiba (Technological Village of Curitiba), in Curitiba, Brazil. Two dwellings were evaluated, which were built according to different building systems: (1) the building system Batistella, built with pre-fabricated modules and elements, composed of reforestation wood and (2) the building system Constroyer, composed of expanded polystyrene (EPS) plates, framed in a welded iron mesh, with structural plastering. For the thermal performance evaluation, it was verified that the materials used in the envelope were quite significant for controlling heat gains and losses through the building elements as well as for regulating heat storage. In this case, the system with highest thermal inertia presented better results. Results showed that both building systems had poor acoustic performance, characterized by a low weighted apparent sound reduction index of the façade dB. The German DIN 4109 Norm recommends a minimum of dB. The weighted apparent sound reduction index measured for internal walls was dB and dB, for the building systems Battistela and Constroyer, respectively. The minimum required by German regulation VDI 4100 is dB, for internal walls.     

光刻物镜中压电陶瓷驱动器的动态性能研究

针对压电陶瓷在光刻机投影物镜中作为像质补偿镜组促动器的特定应用要求,对一种以集成运算放大器构成的压电陶瓷驱动器的动态性能进行了研究.首先,针对驱动器系统中集成运放固有频率特性对动态性能的影响进行了分析,确定了外部补偿网络的参量.然后,针对驱动器系统大容性负载对动态性能的影响进行了分析,提出了隔离电阻的补偿方法.最后,讨论了驱动器系统中寄生电容对动态性能的影响.计算表明:补偿后的压电陶瓷驱动器系统相位裕量为79 °,阶跃响应无超调量,调节时间为5 μS.基本满足压电陶瓷在光刻物镜中作为像质补偿镜组促动器的稳定性强、响应快速、超调量小等动态要求.     

光刻物镜中压电陶瓷驱动器的动态性能研究

针对压电陶瓷在光刻机投影物镜中作为像质补偿镜组促动器的特定应用要求,对一种以集成运算放大器构成的压电陶瓷驱动器的动态性能进行了研究.首先,针对驱动器系统中集成运放固有频率特性对动态性能的影响进行了分析,确定了外部补偿网络的参量.然后,针对驱动器系统大容性负载对动态性能的影响进行了分析,提出了隔离电阻的补偿方法.最后,讨论了驱动器系统中寄生电容对动态性能的影响.计算表明:补偿后的压电陶瓷驱动器系统相位裕量为79°,阶跃响应无超调量,调节时间为5 μs.基本满足压电陶瓷在光刻物镜中作为像质补偿镜组促动器的稳定性强、响应快速、超调量小等动态要求.     

基于太赫兹光谱的奶粉中葡萄糖及蔗糖定性定量检测方法

奶粉富含人体所需的五大营养物质,是婴幼儿主要的营养来源之一,奶粉中的营养成分对婴幼儿的生长发育具有重要影响,除乳糖外的糖类含量超标可能对婴幼儿健康产生不良影响。由于奶粉成分复杂,目前的色谱法和近红外光谱法检测技术都难以满足奶粉糖分快速无损检测的要求,因此亟须探索一种奶粉中葡萄糖、蔗糖含量快速无损检测方法。太赫兹波对不同大分子物质的吸收峰具有“指纹”特性,可利用该特性对不同的大分子物质进行识别。应用太赫兹时域光谱技术（THz-TDS）并结合化学计量学方法对奶粉中葡萄糖、蔗糖两种糖分的定性定量检测方法进行了研究。实验装置采用TAS7500TS太赫兹光谱系统,实验样品为不含糖的婴幼儿奶粉和纯度大于99%的葡萄糖、蔗糖晶体及不同梯度浓度的奶粉-葡萄糖、奶粉-蔗糖混合物,实验分别采集了3种纯品样品及15种不同梯度浓度的奶粉-葡萄糖、奶粉-蔗糖混合物样品的太赫兹时域信号,每个样品采集三次并取平均值作为其时域光谱信号,经快速傅里叶变换（FFT）得到各样品的太赫兹频域信号,再根据Dorney提出的光学参数提取公式计算得到各样品的吸收系数谱和折射率谱。最后分别基于两组混合物样品的吸收系数谱和折射率谱数据,采用偏最小二乘法（PLS）建立相应的定量分析模型,校正集和预测集样品比例为2∶1。实验结果表明,奶粉在太赫兹波段无明显特征吸收峰,葡萄糖和蔗糖分别在1.45,1.8,1.98,2.7 THz和1.5,1.9,2.6 THz频率处有较强的特征吸收峰,可根据两种物质的太赫兹指纹特征峰进行定性分析。不同梯度浓度的两组混合物的整体吸收峰位置与葡萄糖、蔗糖纯品太赫兹吸收峰位置基本一致,具有稳定的吸收特性。基于吸收系数谱和折射率谱数据建立偏最小二乘法模型,均可实现奶粉中葡萄糖和蔗糖的定量分析,且由折射率谱建立的葡萄糖、蔗糖定量回归模型效果均优于由吸收系数谱建立的模型效果,其中,奶粉-葡萄糖混合物中葡萄糖含量PLS模型的校正集相关系数（R_c）及均方根误差（RMSEC）分别为0.99和0.18%,预测集R_P及RMSEP分别为0.96和0.66%,奶粉-蔗糖混合物中蔗糖含量PLS模型的校正集R_c及RMSEC分别为0.96和0.55%,预测集R_P及RMSEP分别为0.99和0.25%,葡萄糖和蔗糖定量模型的预测效果均较为理想。研究结果表明THz-TDS技术可有效用于奶粉中葡萄糖和蔗糖定性定量分析,为运用THz-TDS技术开展奶粉掺假及品质快速检测方法研究提供参考。     

交叉旋翼悬停气动性能和流场干扰

针对交叉旋翼复杂的气动干扰问题,建立了一种适合于交叉旋翼气动分析的数值模拟方法.该方法采用三维非定常Reynolds平均Navier?Stokes(RANS)方程来求解流场,使用动态嵌套网格方法模拟旋翼运动.使用共轴旋翼悬停实验结果验证了该方法的准确性.利用该方法模拟了交叉旋翼在不同状态下的流场,计算了拉力和悬停效率,...     

Color Appearance Explained,Predicted and Confirmed by the Concept of Recognized Visual Space of Illumination

Ten years have passed since we proposed a new concept called recognized visual space of illumination (RVSI). The central idea of the concept assumes that our brain first recognizes how a space is illuminated and then judges colors of anything seen in the space in relation to the RVSI constructed for the space. In another expression we say that the space is recognized first and the color perception next. In this paper some of our experiments that proved the appropriateness of the concept will be introduced. When a white paper was seen through a colored filter we could perceive the paper as white at the same instant we recognized a space through and beyond the filter. When an achromatic patch independent from the room illumination was observed under colored illumination its appearance immediately changed to that roughly opponent to the illumination color. When two gray patches of the same lightness were drawn in a picture of a white grating on a black background on a way that one appeared to locate on this side of the grating and the other in the other side, the former appeared brighter. These all confirmed the predictions based on the RVSI concept.     

眼模型下的投影式头盔物镜设计及视空间评价

进一步完善了投影式头盔系统的视空间评价方法,应用接近实际情况的眼模型来模拟人眼对头盔物镜系统进行评价。由视空间的评价结果出发,从眼模型的成像效果反过来进一步指导头盔系统的设计工作。设计结果显示,轴上视场和大视场的调制传递函数特性良好,在轴上视场可以达到1′的人眼最小分辨角,在大视场可以达到微显示器单个像素确定的视锐度,表明此系统在视空间的分辨力满足实际使用需要。系统最大畸变小于5%,色差不会对人眼分辨产生影响。     

复叠系统低温级制冷剂的循环性能对比实验

通过实验测试,比较了不同冷凝温度和蒸发温度下复叠系统低温级常用制冷工质R13、R23、R503和RS08B的COP、压比及制冷量等循环性能,又结合各制冷工质的环境性能、热工性能,分析了现有常用复叠系统低温级制冷工质各自的优缺点,为新工质的开发及进一步的制冷性能对比实验工作提供了有益的帮助.     

Effects of Match Location,Quality of Opposition and Match Outcome on Match Running Performance in a Portuguese Professional Football Team

The aim of this study was to analyze the effects of match location, quality of opposition and match outcome on match running performance according to playing position in a Portuguese professional football team. Twenty-three male professional football players were monitored from eighteen Portuguese Football League matches during the 2019–2020 season. Global positioning system technology (GPS) was used to collect time-motion data. The match running performance was obtained from five playing positions: central defenders (CD), fullbacks (FB), central midfielders (CM), wide midfielders (WM) and forwards (FW). Match running performance was analyzed within specific position and contextual factors using one-way analysis of variance (ANOVA) for repeated measures, standardized (Cohen) differences and smallest worthwhile change. CM and WM players covered significantly greater total distance (F = 15.45, p = 0.000, η² = 0.334) and average speed (F = 12.79, p < 0.001, η² = 0.294). WM and FB players covered higher distances at high-speed running (F = 16.93, p = 0.000, η² = 0.355) and sprinting (F = 13.49; p < 0.001, η² = 0.305). WM players covered the highest number of accelerations (F = 4.69, p < 0.001, η² = 0.132) and decelerations (F = 12.21, p < 0.001, η² = 0.284). The match running performance was influenced by match location (d = 0.06–2.04; CI: −0.42–2.31; SWC = 0.01–1.10), quality of opposition (d = 0.13–2.14; CI: –0.02–2.60; SWC = 0.01–1.55) and match outcome (d = 0.01–2.49; CI: −0.01–2.31; SWC = 0.01–0.35). Contextual factors influenced the match running performance with differential effects between playing positions. This study provides the first report about the contextual influence on match running performance in a Portuguese professional football team. Future research should also integrate tactical and technical key indicators when analyzing the match-related contextual influence on match running performance.     

瞬态微光探测系统逻辑控制设计与实现

提出一种系统探测的逻辑控制方案．该方案以FPGA设计技术为核心，基于模块化编程思想，实现整个系统的逻辑控制功能．通过计算机仿真和实际电路测试，给出ens、ad_elk、oe、hbe等关键信号的逻辑时序仿真和测试波形．信号处理通道转换、电路延时、功耗等指标分析与测试表明，设计具有实时性、高集成度、高可靠性、低功耗和灵活性等特点．     

基于空时域约束模糊核聚类的红外多时相地下目标探测

提出了一种具有空时域约束的模糊核聚类红外多时相浅层地下目标探测算法.首先在经典模糊聚类算法基础上引入空间和时相变化信息,给出时相信息指数;然后根据时相信息指数修正时相权重因子,将空时域约束加入到多时相模糊核聚类中对红外多时相图像进行分类;最后由分类结果给出地下目标的位置及目标大致种类数,并根据地下目标的红外成像机理获得目标的大体物理性质来提高地下目标探测的准确性.结果表明,所提算法对地下浅层目标具有较好探测准确度.     

Quantification of Low Concentrations of DNA Using Single Molecule Detection and Velocity Measurement in a Microchannel

We present a novel method for quantifying low concentrations of DNA based on single molecule detection (SMD) for molecular counting and flow measurements inside a microchannel. A custom confocal fluorescence spectroscopic system is implemented to detect fluorescent bursts emitted from stained DNA molecules. Measurements are made one molecule at a time as they flow through a femtoliter-sized laser focal probe. Durations of single molecule fluorescent bursts, which are found to be strongly related to the molecular transit times through the detection region, are statistically analyzed to determine the in situ flow speed and subsequently the sample volume flowing through the focal probe. Therefore, the absolute concentration of a DNA sample can be quantified based on the single molecule fluorescent counts from the DNA molecules and the associated probe volume for a measured time course. To validate this method for quantifying low concentrations of biomolecules, we tested samples of pBR322 DNA ranging from 1 pM to 10 fM (∼3 ng/ml to 30 pg/ml). Besides molecular quantification, we also demonstrate this method to be a precise and non-invasive way for flow profiling within a microchannel.     

Evaluation of the scientific impact,productivity and biological age based upon the h‐index in three Latin American countries: the materials science case

We discuss the scientific impact of Latin American scientists in the field of materials science. The analysis is based on the h‐index as the scientometric index used to quantify the scientific productivity of an individual. In particular, we focus our analysis in México, Chile and Colombia. We compare the level of productivity between all these countries. We also analyzed the h‐index as function of the biological age, by using the first year of publication of a given scientists as a reference and discussed the general distribution of its quantification. We do not find a clear relationship between these two quantities. Based in our results we propose some political measures that these countries could implement to improve productivity as well as scientific development in this field.     

微量子腔结边电荷极化结构中的线性和二阶非线性动态电导性质的研究

采用有效哈密顿量和有相互作用的分立势模型，利用格林函数和耦合参量得出了量子点(腔)在有结边电荷积累极化时的线性和二阶非线性交流电导虚部(emittance)的明确表达式.发现在经典情况下，电导虚部和电化学电容都等于经典的几何电容.在非经典情况下，如果发生全反射，电导虚部和电化学电容相等，但两者皆不等于经典的几何电容.在有隧穿的情况下，电导虚部和电化学电容以及经典电容三者都不相等.该结果对于量子器件中的电容测量具有指导作用. 关键词： 格林函数 交流电导 电化学电容     

NQR炸药检测系统中激励脉冲拖尾的抑制

介绍了核四极矩共振（Nuclear Quadrupole Resonance简称NQR）炸药检测系统的基本原理及检测过程中面临的如何消除激励脉冲信号拖尾对NQR检测信号的影响问题. 文中采用了在发射电路中增加消振铃电路来消除激励脉冲拖尾的方法，并给出了电路分析和实验结果. 经实际应用验证，该种方法对消除激励脉冲拖尾具有较好的效果，提高了系统的探测能力.     

Detection of hypersound by means of a phonon-photon double-resonance technique in the paramagnetic systems MgO: Fe3+ and MgO: Fe2+

We report a novel technique for the detection of hypersound by means of phonon-photon double resonance. This technique seems especially suitable for very-high-frequency phonons. Experiments were performed in the X-band with a modified apparatus for Electron Paramagnetic Resonance (EPR) combined with a hypersound pulse-echo equipment. Phonon pulses of about 1 μs duration could be detected in the paramagnetic systems MgO: Fe³⁺ and MgO: Fe²⁺. This kind of incoherent phonon detector is sensitive only in a narrow frequency band, can be tuned, and can easily be applied in several frequency ranges without changing the experimental set-up.