含长链烷基芘类衍生物的合成与氧猝灭特性

采用酯化反应,合成了系列芘丁酸烷基酯和烷基酸芘丁酯,用IR和1HNMR表征分子结构,采用荧光分光光度计测定了它们在溶液中的荧光特性.结果表明,芘类衍生物的取代基、键桥对激发波长、发射波长和氧猝灭系数的影响较大,以OOC键结方式的烷基酸芘丁酯具有更高的氧猝灭性能,烷基链长短对荧光强度和氧猝灭系数影响不大.     

芘丁酸在玻璃基片表面的单层自组装

利用表面反应,在玻璃基片表面引入芘丁酸分子,制备成单分子层自组装荧光薄膜,测定了薄膜的润湿性和荧光光谱,考察了酰胺化温度对荧光传感薄膜荧光特性的影响,探究了薄膜在不同溶剂中的稳定性。结果表明,芘丁酸分子成功地固定在玻璃基片表面,降低温度对酰胺化反应有利,以及不同的介质对薄膜的稳定性有较大影响。     

一种含长链烷基芘类衍生物的光学压敏涂料的氧猝灭特性及热稳定性

利用芘丁醇和8-壬烯酸的酯化反应,合成了含长链烷基的芘类衍生物8-壬烯酸芘丁酯,用红外光谱(IR)和核磁共振(1H-NMR)表征其分子结构,研究了它在甲苯和硅树脂中的荧光特性和热稳定性,考察了不同芘类衍生物对光学压敏涂料热稳定性的影响。结果表明,合成的含长链烷基的芘类衍生物8-壬烯酸芘丁酯在溶液及涂料中都具有较高的氧猝灭率,随着芘类衍生物链长的增长,荧光分子在溶液及涂料中的氧猝灭率略有减小,而在涂料中的热稳定性有较大的提高。     

侧链含芘丁酸酯结构单元的聚氧硅烷合成与氧猝灭特性

采用氢化硅烷化反应，合成了侧链含芘丁酸结构单元的聚氧硅烷荧光高分子。用FTIR和^1HNMR表征了它们的分子结构，采用荧光分光光度计测定了它们在溶液中的激发光谱、发射光谱和氧猝灭系数。结果表明，在聚氧硅烷侧链上引入长链烷烃芘衍生物后，由于侧基上芘环的相互作用，在高波长的受激态发射区（Excimer Emssion）具有强的发射峰，而低波长的分子态发射区（Monomer Emission）的强度较弱。聚氧硅烷荧光高分子对氧气敏感，具有较高的氧猝灭系数，在ME区和EE区的氧猝灭系数分别为59％和54％。随着溶液浓度的降低，在ME区的强度增加，氧猝灭系数增大，而在EE区的强度减弱，氧猝灭系数增加不大。     

表面分子印迹共轭聚合物传感薄膜对2,4-DNT的选择性响应

将侧链含氨基的强电子离域性共轭聚合物(PDD)化学键合到纤维素纳米微纤(TOCN)薄膜上,利用表面分子印迹技术,制备了以2,4-二硝基甲苯(2,4-DNT)为模板的表面印迹共轭聚合物传感薄膜(MI-PDD/TOCN薄膜);并深入研究了该MI-PDD/TOCN薄膜对2,4-DNT检测的应用。研究结果显示,TNT溶液(或蒸气)对MI-PDD/TOCN薄膜的荧光猝灭常数(或荧光猝灭效率)仅为1.6×104M-1(或暴露300 s,18.2%),而2,4-DNT溶液(或蒸气)对其的荧光猝灭常数(或荧光猝灭效率)高达2.78×104M-1(或暴露300 s,88.4%),表明了MI-PDD/TOCN薄膜对2,4-DNT分子具有优良的响应灵敏度与特异的选择性。     

含芘的超支化介孔聚合物的合成及对硝基芳烃的荧光传感性能

合成了以金刚烷为核心,以二苯乙炔基芘为连接臂的超支化聚合物P。金刚烷的三维立体结构及分子骨架的刚性结构特点,赋予了聚合物多孔的结构特点。研究结果表明,聚合物P具有均匀的狭缝孔道结构,其孔径多分布在10 nm左右,属于介孔材料。此外还合成了共聚单体二苯乙炔基芘(M)用于对比研究其光学性质及对硝基芳烃的荧光猝灭性能。聚合物P与单体M相比具有更大的Stokes位移,二者在含有三硝基甲苯(TNT)的溶液中,其平衡时的猝灭率几乎相同。然而二者在相同条件下制备的旋涂膜在二硝基甲苯(DNT)饱和蒸汽中,当达到猝灭平衡时,聚合物P的猝灭率为82%,而化合物M的猝灭率仅为22%。说明聚合物P多孔的特点使其透气性大大提高。以不同浓度的聚合物溶液制备出一系列厚度不同的薄膜,发现随着薄膜厚度的增加,荧光峰发生红移,但在DNT饱和蒸汽中的猝灭率变化不大。这种介孔的结构特点在一定程度上克服了旋涂膜传感器的猝灭率对厚度的依赖性。     

侧链含芘基聚氧硅烷的合成及荧光性质

利用氢化硅烷化反应,合成了几种侧链含芘基但链长不同的聚氧硅烷荧光高分子,用红外光谱(FT-IR)和核磁共振(1H-NMR)表征了其分子结构。采用荧光分光光度计分别测定了荧光高分子与其单体小分子在溶液中的荧光性质。聚氧硅烷荧光高分子与其单体分子相比,受激态发射区比分子态发射区具有更大的的荧光发射强度和较高的氧猝灭系数(OQS)。随着分子侧链长度的增加,单体分子的OQS逐渐递减,而荧光高分子的OQS逐渐增加。     

氧化石墨烯对L-色氨酸荧光猝灭及机理研究

采用改进的Hummers法制备氧化石墨烯,并用红外、拉曼光谱和扫描电镜等手段对氧化石墨烯的结构及形貌进行表征,考察了不同溶剂对L-色氨酸荧光光谱的影响;分别以L-色氨酸、氧化石墨烯为荧光剂和荧光猝灭剂,借助荧光光谱法研究了氧化石墨烯对L-色氨酸的荧光猝灭作用。根据紫外吸收光谱、Stern-Volmer方程和Lineweawer-Burk双倒数曲线方程,得出了氧化石墨烯对L-色氨酸荧光猝灭类型、猝灭速率常数(k_q)和结合常数(K)等参数。结果表明,氧化石墨烯对L-色氨酸的荧光有较强的猝灭作用,其荧光猝灭机理是氧化石墨烯与L-色氨酸形成复合物的静态猝灭。     

自组装单分子膜的末端基团对化学气相沉积铜薄膜的影响

利用化学气相沉积(CVD)的方法在自组装单分子膜(SAMs)修饰的SiO2表面沉积铜薄膜,并对得到的铜薄膜的性质进行表征与分析.通过比较研究发现:在沉积过程中,SAMs的末端基团作为铜沉积的反应位点,末端基团与铜之间的相互作用力越强,则铜在基材表面的沉积与附着能力越强,而且SAMs阻挡铜原子扩散进入硅内部的效果越好.而SAMs的生长取向也会对铜沉积时的晶型产生影响.     

Pd(Ⅱ)与牛血清白蛋白相互作用的荧光光谱研究

采用荧光光谱法研究了Pd(Ⅱ)与牛血清白蛋白(BSA)的相互作用.使用高斯多峰拟合法对Pd(Ⅱ)-BSA体系荧光光谱的各荧光成分进行了解析.结果表明,BSA的荧光主要来源于色氨酸(Trp)残基,并推测Pd(Ⅱ)与BSA结合作用的位置在第212位Trp残基上.研究了Pd(Ⅱ)与BSA相互作用的荧光猝灭光谱,通过紫外吸收光谱的变化和猝灭速率常数Kq的比较对Pd(Ⅱ)与BSA相互作用的荧光猝灭机理进行了判别.结果表明,Pd(Ⅱ)对BSA的荧光猝灭属于静态猝灭.     

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.……     

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...     

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.     

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.……     

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.     

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.     

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 ...