基于OSA-UCS数据的CIECAM02图像复制色差评价

目的为了改进彩色图像复制时在不同观测环境下的误差,将优化后的色貌模型引入色彩信息转换。方法在分析CIECAM02-Jab用于彩色图像复制的色彩评价的基础上,提出利用OSA-UCS数据集建立新的优化色貌空间实验方案。利用线性回归的方法,调整原始颜色空间中的明度和彩度,构建出新的均匀颜色空间J_xa_xb_x。结果经过检验发现新的优化色貌空间J_xa_xb_x色差的离散程度减轻,空间更趋均匀,更加符合均匀性标准。结论新的优化色貌空间J_xa_xb_x修正了均匀颜色空间的均匀性,比CAM02初始色貌空间有了一定程度的提高,对彩色图像复制的色差评价取得了一定的效果。     

封头结构对板翅式换热器流体分配性能的影响

研究了板翅式换热器封头高度与流体分配之间的关系,实验结果说明板翅式换热器的流体分配与封头高度有很大关系,封头高度越高流体分配就越均匀.引入不均匀参数,以便可以对流体在出口截面的分配特性进行研究,并进一步研究封头结构型式不同对于流体分配的影响,研究表明:换热器内部流体的流速的最大值与最小值的比值由3-4减少到1.1-1.2,其不均匀度也从原来的0.331减少到0.046.     

包装颜色空间不均匀性的数理研究

颜色空间的不均匀性是造成包装设计原稿与包装产品之间色差的重要原因.本文从数理角度研究了颜色空间不均匀性产生的原因,介绍了一种新的颜色空间模型——仿射颜色空间,并探讨了颜色空间在包装设计中的选择和应用.     

利用离散平稳小波变换改进NURBS二次曲面拟合方法

为了提高二次曲面的拟合精度,提出了一种基于离散平稳小波变换的NURBS二次曲面的拟合方法。 首先利用格网化方法得到二次曲面模型点云数据的高程图像及其高程序列,其次对此高程序列进行离散平稳小波变换提取出二次曲面模型表面的特征点,最后利用提取的特征点实现高精度NURBS二次曲面拟合。实验结果表明,该方法与NURBS拟合方法相比,球面和圆锥面拟合结果的均方根误差分别降低了55.79%和50.47%,具有较高的拟合精度。     

离散频谱分析中两邻近谱峰参数的识别

在理论概括比值法原理的基础上,提出一种新的自动识别和修正离散频谱中两邻近谱峰参数的方法.它保留了比值法计算简单的特点FFT谱分析时无需增加样本长度,谱峰参数修正识别的算法简单,无迭代搜索过程.不仅能识别间距不到一个频率分辨率的两个密集频率成份,而且能识别峰间距为1～6个频率分辨率的邻近谱峰参数,从而与比值法相辅相成,形成了一套完整的离散频率信号分析方法.仿真研究表明,该方法能有效克服窗谱函数主瓣干涉和旁瓣泄漏的影响,识别精度较高当峰间距大于0.2倍频率分辨率时,对于两个频率分量的各种截断情况,均能保证幅度误差小于6%,相位误差在5°以内.     

HHHT抽水蓄能电站地下主厂房母线层通风模型试验研究

通过HHHT抽水蓄能电站地下主厂房1：20缩尺模型来研究其母线层气流组织分布。在56m^3/h及112m^3／h的两种风量下,分别选择5种送风口方案1～5,对母线层工作区温度场及速度场进行测试。未封闭吊物孔、未安装接力风机时的温度分布标准差最大值为0．95,最小值为0．42：封闭吊物孔、安装接力风机后的温度分布标准差最大值为0．35,最小值为0．08。研究表明,封闭吊物孔、安装接力风机加强了母线层工作区气流组织分布的均匀性,双排对称布置送风口（方案5）为最佳送风口方案。研究结果为HHHT及相关电站地下厂房复杂气流的优化组织设计提供了参考依据。     

影院建筑声学标准与测量(下)

2.声场分布及声缺陷的测量: 在影院及其它厅堂中,为使观(听)众区内任意位置都能清楚地听到对白、语言、音乐、动效等内容,故声场分布的均匀性也极为重要。 在相关标准中规定“在观众区内各测试点间声压级的最大值与最小值之差不大于6dB,最大值与平均值之差不大于3dB。”     

供料方式对垂直螺旋输送机性能的影响

为了研究供料口处物料呈现的不均匀现象,分别建立了重力型和水平型2种供料方式下的垂直螺旋输送机计算模型,采用离散元法,借助EDEM软件,通过试验和标定的方式对模拟参数,如进口速度、时间步长和颗粒属性参数进行确定,进而确保模型和参数选取的可行性;分别对2种供料方式进行模拟,以颗粒数标准偏差为评价指标。结果表明:与重力型供料相比,在相同的操作条件下,水平型供料方式在供料口取样区域的物料不均匀度更高,物料输送的均匀性更低,螺旋转速的改变对2种供料方式下取样区域颗粒质量分布的均匀性影响较大,针对重力型和水平型供料方式给出了结构改进建议。     

封头形状对板翅式换热器入口段流场影响的数值研究

板翅式换热器入口段存在流场分布不均匀,并由此会引起换热效率低下.首先从封头曲线对流体的引导作用出发,进而优化换热器入口段流场均匀性,提出了板翅式换热器一次封头进一步的改进和优化思路和方法.即结合封头截面曲线函数及其导数特性,将前人提出的下抛物型一次封头改进为上抛物型和正切型,并利用CFD数值模拟方法对3种封头条件下换热器入口段的流场分布进行了对比研究.研究结果表明,使用后两种曲线的封头时,换热器入口段的物流分配更为均匀,在入口条件为7 m/s时,流速不均匀度由封头Ⅰ的5.9分别下降到0.5和0.4;流速最大值与最小值之比由封头Ⅰ的73.6分别下降到60.5和41.5.     

数控加工仿真中的优化离散矢量模型

数控加工仿真是利用计算机模拟数控加工的过程。采用离散知音一法可以有较好的实时性和观察性。但在采用离散矢量法时，离散模型的建立对仿真的效果有很大的影响。而对于常用的彩和均匀离散方式建立起来的仿真模型，对仿真精度与仿真速度的要求无法同时得到满足，本文采用了一种基于非均匀离散的优化模型可以有效地解决此点不足，并将详细论述这种仿真模型的建立、数据更新及其显示等内容。     

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.     

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.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

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.……     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...