有机低分子三阶非线性光学材料

介绍了三阶非线性光学原理.根据分子结构特征对各类有机低分子三阶非线性光学材料的结构与性能关系作了评述,提出了分子设计有机三阶NLO材料的一些规律性结论.离域能小的共轭骨架,长的共轭链,吸供取代基的引入,取代基强的供电子性或吸电子性,长的吸供电子取代基之间的距离,以及良好的共平面程度等因素均有利于获得较大的三阶NLO性能.     

取代二苯多烯和取代聚二乙炔的三阶非线性光学性质

为了设计新的具有较高非线性极化率和光损耗小的有机非线性光学（ＮＬＯ）材料，需要了解不同的有机结构对分子非线性的影响。在此基础之上，建议用平行对比的方法来近似估算取代二苯多烯和聚二乙炔（ＰＤＡ）的三阶非线性光学极化率。     

醌构稠杂环系有机三阶非线性光学材料的合成和性质研究

分子设计并合成了三大系列的醌构稠杂环化合物,由有机光波谱分析验证了各化合物的结构。用一维简并四波混频实验测定并计算了各化合物溶液的红外区,非共振三阶非线性光学极化率Ｘ（３）和分子三阶非线性光学超极化率γ。研究了分子结构对三晨线性光学性质的影响。     

有机三阶非线性光学材料的研究进展

对有机三阶非线性光学响应的理论及实验（包括器件对材料的要求，理论研究，三阶极化率的测试技术，有机三阶光学材料）进行了综述。     

金属有机非线性光学材料

本文介绍了非线性光学的简史，非线性光学材料的分类及应用，简述了金属有机非线性光学材料的原理，从分子工程和晶体工程的角度讨论了金属有机非线性光学材料的结构与性质的关系，综述了目前已研究的金属有机化合物和金属有机聚合物的二阶、三阶非线性光学材料，二阶非线性光学材料按目前所做的工作可以分成二大类：一类是含有芳香基或杂环的过渡金属羰基化合物；一类是含有二茂铁基和吸电子基的共轭体系化合物。三阶非线性光学材料的研究工作主要集中在酞菁类的金属配合物上，本文对金属有机化合物作为非线性光学材料的独特之处进行了总结，并对金属有机非线性光学材料的前景作了展望。     

三阶非线性光学效应概述

由于三阶非线性光学效应具有普遍性,因此人们对大多数材料的非线性特性的研究主要是对材料的三阶非线性特性的研究[1]。对三阶非线性光学效应进行详细的介绍。     

有机三阶非线性光学材料的研究进展

非线性光学材料在图像处理、全光开关、光学存储和记忆系统等领域有着较大的应用潜力,近年来对三阶非线性光学聚合物材料的研究成为研究工作中的热点.分类介绍了各种有机三阶非线性光学聚合物的合成、结构与性能的最新研究进展,评述了三阶非线性光学性能表征技术的研究状况,展望了有机三阶非线性光学材料的前景和存在的问题.     

共轭高分子三阶非线性光学材料

概述了ｎ－共轭高分子材料的三阶非线性光学性质，着重讨论了化学结构对其光学非线性的影响，说明了ｎ－共轭聚合物的三阶非线性极化率主要取决于共轭主链的结构，侧链取代基的变化对其非线性影响不大，文中展望了共轭高分子材料在集成光学中的应用前景。     

基于酞菁光控自组装的超分子三阶非线性光开关材料

酞菁的三阶非线性光学性能不仅取决于其分子结构，而且与酞菁分子在空间的排列密切相关。因此，控制酞菁化合物在空间的排列状态，就有望在超分子的层次控制酞菁的三阶非线性光学性能。我们设计了三类含有光致变色单元修饰的酞菁化合物。利用紫外光和可见交替照射下光致变色单元光异构过程中空间结构和电子结构的改变，实现了对酞菁自组装行为的有效光控。我们用Z-扫描的方法考察了光照前后这些酞菁光控自组装体系三阶非线性光学性能的改变。发现：这些材料不仅开关效应显著，且在“开”和“关”的状态下，都具有大的二阶分子超极化率（〉10^-30esu），在未来光电子和光子技术领域具有潜在的应用价值。     

有机功能色素类化合物的合成与三阶非线性光学性能

设计并合成了苯并二呋喃酮、双偶氮-9,10-蒽二酮、苯并噻蒽以及偶氮-1,3,4-噻二唑4个系列的有机色素类化合物,并用UV,IR,1H NMR和元素分析表征了结构.采用飞秒激光,运用简并四波混频法,研究了化合物的三阶非线性光学性能.它们的三阶非线性光学极化率χ(3)为2.64～3.95×10-13esu,非线性折射n2为4.85～7.27×10-12esu,分子二阶超极化率γ为2.85～3.72×10-31esu.探索了化合物的分子结构对三阶非线性光学性能的影响.长的共轭链、吸供取代基和杂环的引入、取代基强的供电子或吸电子能力等因素有利于获得较大的三阶非线性光学性能.     

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 ...