JJF 1059-1999《测量不确定度评定与表示》讨论之三十八影响测量结果的两和效应与所导致的不确定度分量和误差分量

1两种效应在给定条件下的重复观测中,影响测量结果的效应,按其对测量结果的影响,分为系统效应( systematic effect)和随机效应(random effect)两种.系统效应指那些对测量结果的影响带有系统性的效应,例如:导致系统性地偏大或偏小,甚至偏大或偏小到某一程度,可以定量地给出一个值或一个可能的区间,如果系统效应造成的影响通过实验或通过信息可以估计出一个近似值,则就是测量结果系统误差的估计值而可据以得出修正值或修正因子,如果只知道某种效应对测量结果造成系统性的影响,未能估计出一个近似值,一般均能按实验结果或某些信息估计出所导致的分散区间.     

精密酒精计的不确定度及符合性评定

本文分析了影响酒精计修正值的不确定度因素,主要包括:测量重复性、二等标准酒精计的示值、二等标准酒精计的修正值、被检酒精计示值、环境温度、液体毛细常数变化、表面张力、空气浮力、垂直偏差和数据修约,从而评定精密酒精计修正值的不确定度,对白酒企业中的科学计量、理化检测和数据分析提供参考依据。     

精密酒精计的不确定度及符合性评定

文章分析了影响酒精计修正值的不确定度因素,主要包括:测量重复性、二等标准酒精计的示值、二等标准酒精计的修正值、被检酒精计示值、环境温度、液体毛细常数变化、表面张力、空气浮力、垂直偏差和数据修约,从而评定精密酒精计修正值的不确定度,对白酒企业中的科学计量、理化检测和数据分析提供参考依据。     

基片表面粗糙度对坡莫合金AMR以及磁性能的影响

利用霍尔离子源轰击Si基片获得了不同表面粗糙度的基片,然后利用磁控溅射方法制备了一系列Ta(5nm)/Ni 80Fe 20(12nm)/Ta(2nm)薄膜样品,重点研究了基片表面粗糙度对薄膜结构和各向异性磁阻效应的影响。采用AFM测量基片的表面粗糙度,采用四探针法测量薄膜的各向异性磁阻效应。研究结果表明,随着基片表面粗糙度的增加,坡莫合金的AMR值显著降低,且ΔH显著增加。     

酒精计修正值的不确定度评定

浮计检定采用直接比较法,将二等标准酒精计与被检酒精计同时浸入同一检定液中,直接比较它们标尺的示值,从而得到被检酒精计的修正值。影响酒精修正值的不确定度因素有二等标准酒精计组、被检酒精计读数、检定液体毛细常数变化、被校干管不垂直及分度线倾斜、测量重复性。本文通过对这几方面的分析,从而评定酒精计修正值的不确定度,对日后的计量检定提供一些参考。     

基于UV喷墨系统提升3D打印模型表面着色效果

目的研究基于UV喷墨方法获得高质量的3D打印彩色外观。方法基于熔融沉积的成型方法,设计并加工不同打印层厚及倾斜角度的直角梯台模型,通过UV喷墨平台对模型表面进行标准色块着色处理,论述阶梯效应对喷墨着色涂层的影响机理,以及喷墨对于3D打印阶梯效应的修复作用,显微观察模型表面图像,并测量色块颜色的色度值。结果比较分析得出,打印层厚和倾斜角度导致的未着色条纹是影响3D打印模型表面喷墨着色效果的主要因素。结论通过UV白墨涂覆的方法可以修复阶梯效应,从而获得高质量的3D打印彩色外观。     

表面效应对动态光散射纳米粒径测量的影响

为探究表面效应对动态光散射法测量纳米粒度的影响,设计一种宽度可调的样品池,采用基于高速线阵CCD的动态光散射测量系统,对不同粒径的标准SiO_2颗粒进行测量。结果表明:样品池宽度小于1.3 mm时,粒径测量值随通道宽度减小线性增大,宽度为0.6 mm时,粒径测量值与自由空间中的测量值差距超过5%;样品池宽度较小时,颗粒布朗运动受到明显影响,动态光散射仪中使用微量样品池时,应根据样品池宽度对测量结果进行修正。     

近场声全息测量阵架的设计与分析

全息测量系统设计的关键是测量全息面测点复声压(幅值和相位)的真实数据,介绍了自行设计的近场声全息(NAH)测量的传声器线阵扫描系统.利用边界元法计算了传声器线阵架结构表面声散射对阵上传声器测量全息复声压的影响,提出了敷设吸声材料以提高测量精度的措施;对在线阵架表面敷设吸声材料后的声散射效应仿真结果表明,吸声材料能够有效...     

测量吸声系数的多传声器脉冲响应方法

脉冲响应法是测量吸声材料或吸声结构吸声系数的一种简单易行的方法,但使用单个传声器难以排除被测对象散射效应的影响,因此不能测量具有不平整表面构件的吸声系数。针对这一缺陷,本提出了一种用多个传声器同时测量反射脉冲的实验分析技术,可以排除被测对象的反射与散射指向性对吸声系数分析的影响,故可用来测量具有不平整表面吸声结构在各种不同入射方向下的吸声系数。用该方法在半消声室内分析了一种表面呈锯齿形的声屏障斜入射吸声系数,结果表明本提出方法可以满足工程应用的要求。     

影响布氏硬度计准确测量的因素及排除方法

计布氏硬度计的工作原理是把一定直径的钢球,在一定试验力作用下,以一定的速度压入试样表面,经规定的试验力保持时间后卸除试验力,以试样压痕球形表面积上的平均压力来表示金属的布氏硬度值。凡影响压痕产生及测量的因素,均影响布氏硬度值。影响测量准确度的因素主要由四部分组成。一、试样试样厚度及表面质量能明显影响布氏硬度测量结果。(1)尽管布氏方法受粗糙表面的影响小,对表面研磨要求不高,但为使压痕边缘清晰,保证测量结果的准确性,该方法对表面粗糙度也有一定的限制。(2)表面清洁度对布氏硬度测量值和不均匀性也是比较关键的,油脂、…     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.