光谱黑度计的设计

利用常用的X－Y函数记录仪和一些简单的装置制作光谱黑度计，可以绘出光谱的黑度曲线并能精确地测出谱线波长．     

测绘胶片感光特性曲线的新方法

用照度计代替黑度计测绘胶片感光特性曲线，在实验教学中取得良好效果．     

物体的黑度和吸收比不是等同的

物体的黑度和吸收比不是等同的浙江林学院刘德祖在大学物理教学中对物体的黑度和吸收比一般不作较为深人讨论，常产生一些误解．例如，认为物体的吸收比就是它的黑度；实际物体是灰体；气体是完全透明体等．有鉴于此，本文较详细地讨论物体黑度和吸收比，以及黑体、灰体和...     

高速摄影机的点阵数据记录系统

本文介绍了高速摄影机点阵数据记录系统的工作原理；对点阵黑度的几种控制方法进行比较，给出了时间电流黑度控制法的系统实现。     

NCS颜色空间标号的扩充方法研究

为了对现有NCS颜色空间的标号进行扩充,通过分析NCS图谱集上样本的CIE1976L a b 的值与NCS颜色空间坐标的关系,将NCS标号间隔单位由图谱集中的每10个黑度、艳度单位扩充至每1个黑度、艳度单位。应用样条插值、线性插值算法计算出这些扩充标号对应的CIELAB值,并将它们绘制在CIELAB空间图上。     

谱线宽度测量在摄谱分析中的应用

本文介绍了利用谱线宽度进行光谱定量分析，并把上述方法所得的分析结果与黑度法的结黑进行了比较。     

乳胶室实验中X光片的本底与能量定标

对各年度(K0—K7)X光片的本底黑度D_B进行了测量,给出了D_B和能量定标黑度值D₁的关系.对X光片本底的各种分布也作了测量,测量结果可作为能量定标和乳胶室实验其它方面的参数.     

辐射传热中的熵流,熵产和有效能流

以无限大双平行灰体平板等辐射流传热为例,研究了辐射传热的熵流,导出了辐射传热的熵产率,有效能传输效率和理论最佳接收温度的基本通用计算式。通过引入系统黑度的概念,把以上结果应用于复杂辐射传热的热力学分析。针对辐射强度随传递距离不断减弱的辐射传热的非平衡辐射热力学问题,提出辐射强度系数和当量辐射温度的概念,并以太阳能热接收转换器为例,导出了以当量辐射温度表征的辐射能接收转换热效率,熵增强度,有效能输出率,最佳接收温度的计算式,考察了聚光度对提高太阳能接收器有效能输出率的作用。     

循环流化床锅炉火焰温度及黑度图像检测

本文在图像处理技术的基础上提出了一种改进的比色法.对于充满颗粒介质的燃烧过程,该方法可从一个彩色CCD图像中获得介质温度和黑度图像.本方法不依赖于CCD的光谱特性及其三基色代表性波长,也不依赖于图像处理系统.在一台480 t/h燃煤循环流化床锅炉上进行了试验.与热电偶测量结果相比,使用本方法测量温度是可行的,而且其与锅炉负荷的相关性也是明显的.使用本系统得到的火焰黑度可以做进一步的研究.     

砂姜黑土有机无机复合体结构特征及其对土壤颜色的影响机制

土壤颜色是反映土壤发生、形成环境及肥力特征的一项重要物理性状。通常高有机质含量土壤的颜色比较黑,但我国典型低有机质含量的砂姜黑土土壤颜色也很黑。基于传统化学方法的研究认为高度芳构化的腐殖质成分与土粒结合使砂姜黑土呈现黑色。然而采用化学方法只能提取部分腐殖质成分,且破坏了有机质及有机无机复合体的化学结构,其结果不具有代表性。通过不破坏土壤有机无机复合体结构的物理方法从砂姜黑土中提取黑色物质的研究发现蒙皂石吸附有机质形成的黑色有机无机复合体是砂姜黑土呈现黑色的决定性成分。但是,这些黑色有机无机复合体的有机质结构及复合体呈现黑色的机制还不清楚。本研究旨在通过物理方法从砂姜黑土中提取黑色组分,从有机质结构及其与蒙皂石矿物作用方面研究这些黑色有机无机复合体的特征,探讨其呈现黑色的机理。首先采用物理方法从黄淮海平原三个地点的典型砂姜黑土表土层(0～40 cm)土壤中提取浅色组分[53μm颗粒、白(W)和浅白(LW)]和黑色组分[浅黑(LB)、黑(B)和纳米黑(NB)]。然后采用分光测色仪、固态~(13)C核磁共振谱仪和X射线衍射仪分别测定不同提取组分的黑度、有机质结构和蒙皂石含量。相关分析和通径分析结果表明,提取组分有机质的羧基碳、氨基碳、烷基碳和烷氧碳对砂姜黑土黑度的直接影响效应和间接效应都较大,芳香碳含量和芳香度对土壤黑度的影响则较小,蒙皂石对土壤黑度的直接影响效应及其通过羧基碳、氨基碳和烷基碳对土壤黑度的间接效应都较大。因此,砂姜黑土中大量存在的蒙皂石通过吸附有机质中含有生/助色团的羧基碳、氨基碳、烷氧碳及烷基碳形成有机-无机复合体是其呈现黑色的主要机制,并不是传统观点认为的芳香碳及高芳香度。     

High-temperature vibrational densitometer for high-pressure aggressive media

High-temperature vibrational densitometer for chemically active media was developed. The principle of operation of the densitometer is based on recording and analyzing the natural frequency of a U-shaped high-pressure capillary filled with the test medium. The placement of the capillary in a thermostat capable of maintaining its temperature to within ±0.1°C makes it possible to measure the density and study the phase behavior of aggressive media over pressure and temperature ranges of 0.1–50 MPa and 20–500°C, respectively. Measurements of the carbon dioxide density with the densitometer developed at temperature below, near, and above its critical point (31°C), as well as water density measurements at temperatures up to 375°C demonstrated good agreement with the data from the NIST (National Institute of Standards and Technology) interactive database. The density of a methanol-water mixture was measured at temperatures up to 300°C.     

光学密度可见光区光谱特性的理论分析与实验研究

光学密度是评价光学影像材料的具有唯一性的指标。随着高分子影像等的发展,对光学密度的光谱特性的要求也逐渐提高。2001年ISO对光学密度的测量条件作了新的修改规定。按照ISO新标准的光谱特性要求设计了新国家光学透射密度基准装置的组件结构,提出了一种基于光谱特性的光学密度理论测量方案,并进行了实验研究,将光学密度的光谱不确定度提高到0.001 1(0<D<4.0)和0.003 1(4.0≤D<6.0),比国际先进水平有了大幅度提高。     

One dimensional modeling of a step-down ultrasonic densitometer for liquids

This article studies the possibilities and limitations of modeling a step-down ultrasonic densitometer using its electrical analogous representation. The purpose of the model is to simulate the system in order to optimize its performance. The advantage of an analogous electrical is the complete simulation of both the electrical and mechanical parts of the system. The ultrasonic densitometer and the need for the step down are presented. The analogy to the electrical representation is briefly introduced along with the step down notion. Experimental results of probes equipped with piezoceramic disk of 10 and 16 mm in diameter are shown to consider diffraction. Simulated signals from modeled probes are judged against the real signals. The limitations of the simulations are discussed. They are beam spreading, reference echo to different media and superfluous multiple reflections.     

Densitometer for measuring densities in range ofD=0 toD=6

An instrument permitting measurement of the density of a photographic film in a range ofD=0 toD=6 has been designed by simply adapting a normal densitometer. The advantages of this equipment are described as well as the possibilities arising for film dosimetry.     

Measurement of Root Mean Square Granularity of X-ray Films Using a Commercial Film Scanner

Root mean square granularity of films are generally measured using a microdensito-meter, although it is costly and not easily available. To solve the cost problem, we tried to use an inexpensive commercial film scanner. Films with different densities were prepared and the relationship between densities by a diffuse densitometer and pixel values by a film scanner was obtained. We found that a linear relationship exists between rms granularity and a corrected standard deviation of pixel value that is available as an index granularity.This paper was originally presented at the 2nd International Conference on Optical Design and Fabrication, ODF2000 which was held on November 15-17, 2000 at the International Coference Center, Tokyo, Waseda University, Japan.     

High concentration measurements of U and Pu with nondestructive and standardless K‐edge densitometer device

In nuclear activities such as reprocessing plants, safeguard laboratories, or research centers, U and Pu are regularly analyzed. Fast and accurate analytical devices are favored such as K‐edge densitometer. This paper presents the results obtained by this device from assay samples with high U and Pu concentrations. Two processing methods without calibration (except energy calibration) are compared and discussed. Despite literature advising against the use of estimated mass attenuation coefficients for near edge energy, this study shows that these values can contribute to very good results for uranium and plutonium concentration estimations, with a bias less than 1%.     

X光胶片响应曲线的实验标定

 介绍了天津ⅢX光胶片在北京同步辐射源3W1B装置上进行绝对响应标定的一种实验方法。实验中采用快门控制曝光时间,标准探测器记录积分光强,从而得到胶片接收到的绝对光强,并用黑密度计扫描胶片得到光学黑密度。数据处理中通过对快门响应的标定和对光源分布不均匀性的处理来减小光强的不确定度。实验得到了胶片在1 keV和1.5 keV两个能点绝对光强与黑密度之间的绝对响应实验数据,并用Henke的理论公式拟合得到绝对响应曲线。     

Developing a gamma ray fluid densitometer in petroleum products monitoring applications using Artificial Neural Network

In gamma-ray densitometry the determination of density is performed by the use of calibration tables. Calibration and consequently the accuracy of the system can be influenced when a number of important system parameters such as pipe diameter, source to detector distance and so on are changed from one case to another. In this work an Artificial Neural Network model was proposed for developing a previously designed and constructed gamma ray densitometer in prediction of fluid density of different petroleum products. The required data for training and testing the ANN model has been obtained based on simulations using MCNP4C Monte Carlo code. Simulations for 4-inch polyethylene pipe had been validated with the experimental data previously. The Mean Relative Error (MRE) from ANN modeling was less than 0.5%. Results show that proposed ANN model represents a good estimation of the density in petroleum products monitoring application and can be used as a reliable and accurate tool.     

Self-diffusion and density of liquid hexafluorobenzene as a function of pressure and temperature

Measurements of self-diffusion coefficients to pressures of 2000 bar? 1 bar ≡ 10⁵ N m^-2. and densities to 2600 bar, except where limited by freezing, have been made for liquid hexafluorobenzene C₆F₆ at eight temperatures from 15°C to 150°C. The N.M.R. spin echo technique was used for the self-diffusion measurements, and the densities were determined with a densitometer of the bellows-slidewire type. The density data have been fitted satisfactorily to a modified form of the Tait equation, and the self-diffusion results were reproduced by a polynominal in pressure for each isotherm.

Several models of transport in liquids were evaluated. All models depend sensitively upon a quantity ν-ν₀, the difference between the specific volume of the liquid and that of a hypothetical dense solid. The free volume model describes the data only if ν₀ is allowed to depend upon pressure. The hard sphere model failed to describe our results for C₆F₆ at temperatures above 70°C even when the effective hard sphere diameter was treated as an adjustable parameter.     

Influence of Tetra Alkyl Ammonium Cation on Thermo-Physical Properties of N,N-Dimethyl Formamide with 1,4-Dioxane at Different Temperatures

Ultrasonic technique, transport properties and related acoustical parameters of 1,4-dioxane and N,N-dimethyl formamide were prepared of different % compositions at variable temperatures using tetra alkyl ammonium iodide salts (R₄NI) of 0.14 M, to investigate inter-ionic interactions, molecular interactions, molecular rearrangement, molecular association etc. The densities were measured by using magnetic float densitometer. Transport properties provide a deep and meaningful insight of various interactions taking place between the binary liquid mixtures with salts. We have observed the influence of small as well as large alkyl chain length (R₄N⁺), and extract the information with respect to various kinds of intermolecular interactions such as dipole-dipole, dipole-induced dipole, solute-solvent, dispersive type and H-bonding interaction between the components. Such observations in the presence of specific molecular interactions of binary solutions and structural effects were analyzed on the basis of measured and derived thermo-dynamical parameters.