Study on the laser treatment of electroless Ni-P-SiC composite coatings

Effect of the laser treatment on electroless Ni-P-SiC composite coatings was investigated. The microscopic structure, surface morphology, ingredient, and performance of the Ni-P-SiC composite coatings were synthetically analyzed by the use of X-ray diffraction apparatus, scanning electron microscope, energy distribution spectrometer, micro-hardness tester, wear tester and so on. It was found that the composite coatings did make crystalloblastic transformation after laser heating. Structural analysis confirmed that some new types of phase Ni2Si or Ni3Si compound would emerge in the Ni-P-SiC coatings after laser treatment. The micro-hardness measurement results showed that when the laser power was 450 W with scanning speed of 0.5 m/min, the hardness of the coating was superior to the coating obtained by the conventional furnace heating, and wear resistance of the composite coating after laser treating could also improve.     

One—Pot Synthese of 3,4—Dihydropyrimidine—2（1H）—thiones Catalyzed by La（OTf）3

A general and practical procedure for the syntheses of 3,4-di-hydropyrimidine-2(1H)-thiones by a one-pot condensation of aldehyde,β-ketoester or β-diketone and thiourea using La(OTf)3 as the catalyst is described.Mild reaction conditions,excellent yields as well as the environmentally friendly character of La(OTf)3 make it an important alternative to the classic acid-catalyzed Biginelli‘s reaction.     

激光淬火和冲击复合强化处理40Cr钢的耐磨性能研究

对激光淬火40Cr钢强化区域进行激光冲击复合强化处理，并分别同激光淬火和氮化处理40Cr钢对比考察了激光淬火和冲击复合强化处理40Cr钢的表面硬度和耐磨性．结果表明：经激光淬火和冲击复合强化处理的40Cr钢的硬度比激光淬火处理40Cr钢的硬度高11％；同氮化和激光淬火处理40Cr钢相比，复合强化处理40Cr钢的耐磨性分别提高了约4．3倍和1．6倍．     

双齿型配体2[2(二苯基膦基)苯基]4,5 二氢口恶唑的合成及应用

从２溴苯甲酸出发，探索了２ 种不同于文献报道的方法合成２［２（ 二苯基膦基） 苯基］４ ，５二氢嚙唑，并初步考察其与铑的配合物在芳香烯烃氢甲酰化反应中的催化性能．     

光学新分支——梯折光学

 梯度折射率(下面简称梯折)光学,是近些年来引人注目的一门光学分支学科.它的发展已有一百多年的历史.Maxwell鱼睛透镜、Wood透镜、Luneburg透镜以及梯折透镜的研制成功都是梯折光学发展史上的重要里程碑.然而只有在近十几年来,随着计算机科学的发展;像差理论和计算方法的不断完善;梯折材料的研制成功以及测试方法的改进等,梯折光学才有可能在实际上有所应用.1979年美国召开了第一次梯折光学及其材料的专题会议,以后几乎每隔1-2年召开一次.使该课题成为国际上引人注目的一门光学分支学科.七十年代,中科院西安光机所在龚祖同教授和薛鸣球教授等的领导下开展的有关研究课题已取得了很大的成就,使梯折棒透镜在光纤通讯中开始实际应用.     

光学新分支——梯折光学

梯度折射率(下面简称梯折)光学,是近些年来引人注目的一门光学分支学科.它的发展已有一百多年的历史.Maxwell鱼睛透镜、Wood透镜、Luneburg透镜以及梯折透镜的研制成功都是梯折光学发展史上的重要里程碑.然而只有在近十几年来,随着计算机科学的发展;像差理论和计算方法的不断完善;梯折材料的研制成功以及测试方法的改进等,梯折光学才有可能在实际上有所应用.1979年美国召开了第一次梯折光学及其材料的专题会议,以后几乎每隔1—2年召开一次.使该课题成为国际上引人注目的一门光学分支学科.七十年代,中科院西安光机所在龚祖同教授和薛鸣球教授等的领导下开展的有关研究课题已取得了很大的成就,使梯折棒透镜在光纤通讯中开始实际应用.八十年代中,上海光学仪器研究所在庄松林研究员的领导下,进行了梯度折射率材料及其应用的研究,经过几年的努力,在材料的梯度深度和梯度大小方面取得了可喜的进展,并对光线在梯折介质中的传     

Pd/C催化的对异丁基苯乙酮加氢反应

２（４异丁基苯基）丙酸（俗称布洛芬）是一种重要的解热镇痛消炎药物［１］,经典的生产路线是由异丁基苯出发,经弗克反应、达村缩合,最后经氧化制得［２］;其合成步骤多,成品精制难,生产成本高．美国于１９９２年通过１（４异丁基苯基）乙醇（ＩＢＰＥ）羰...     

温控相转移配体及催化(V)——单,双-对聚氧乙烯基三苯基膦的合成及其催化性能研究

近年来,水/有机两相催化已成为均相催化多相化研究的主流[1].其中,新型水溶性瞵配体的合成和两相催化新体系的设计尤为引人关注[2].最近我们发现[3],聚醚型水溶性膦-铑催化剂在高温下可溶入有机相对反应进行催化,而在冷却后又重返水相和产物分离.     

Study of the substructure in nanometer copper thin films treated by laser shock processing

We study nanometer copper thin films prepared by magnetron sputtering and treated with laser shock processing (LSP). We observe the formation of firstborn twin crystals and some complete twin crystals in the copper thin films. After LSP, scanning electron microscope (SEM) images show obvious plastic deformation of the copper grain on the film surface, dramatically increased grain size, and the appearance of a large number of twin crystals. Moreover, the width of the crystals is a few dozen nanometers, and the cross angle is more than or close to 90°.Many vacancy defects appear during the sliding of atomic plane, which leads to a faulty structure; however, no obvious dislocation is observed. These substructures play a significant role in improving the mechanical performance of nanometer copper thin films.     

Microstructure and properties of plastic deformed martensite induced by laser shock processing

Firstly, 45# steel was quenched by the NEL-2500A rapidly axial flow CO2 laser. The experimental parameters were the laser power of 750 W, the laser beam diameter of 4 mm, the scanning velocity of 7 mm/s.The thickness of coating layer was 0.1 mm and the width was 8 mm. Secondly, the martensite induced by laser quench was shocked by Nd:YAG laser. The parameters of laser shock processing were the wavelength of 1.06 μm, the pulse duration of 23 ns, and the output energy of 16-20 J. The laser was focused on a spot of φ7 mm. K9 optical glass was used as confinement. The sample was coated with black paint 86-1 (the thickness is about 0.025 mm). By testing and analysis of samples which were treated by laser quench and laser quench+shock with transmission electron microscope (TEM), it was discovered that the surface layer of martensite was deformed plastically by laser shock processing. In the secondary hardened zones,there were a lot of slender secondary twin crystal martensites, dislocation tangles, and cellular dislocations.Compared with that of the hardened zones through laser quench only, the residual stress and mechanical properties of the secondary hardened zones were improved and increased through laser compound method.