微波辐射相转移催化下水相合成α,α'-双亚苄基环烷酮

芳醛与环戊酮或环己酮在碳酸钠水溶液中, 用微波辐射-相转移催化法合成 α,α'-双亚苄基环烷酮, 反应在0.5～7 min内完成, 产率高达80%～99%, 后处理极为简便, 是一种环境友好的绿色合成.     

高效液相色谱法测定营养液中吩嗪酮含量

建立了高效液相色谱法测定营养液中吩嗪酮含量的方法,采用Aichrom Bond-AQ C18色谱柱(250 mm×4.6 mm,5μm),流动相为甲醇∶水(40∶60,V/V),流速为1.0 mL/min,检测波长为315 nm.外标法定量,吩嗪酮在1.0～200 mg/L(r=0.9996)的浓度范围内呈线性关系.方法的检出限为0.02 mg/L,回收率为96.0%～99.0%,相对标准偏差为0.20%(n=6).该方法简便、准确、易行,可用于质量控制.     

塑料中邻苯二甲酸酯类化合物的高效液相色谱分析

采用高效液相色谱法对塑料制品中的邻苯二甲酸酯类化合物进行了测定。塑料样品经粉碎后，用乙醇溶解后超声提取，直接用高效液相色谱分析，外标法定量。该方法精密度1．07％～1．98％，回收率76．0％～96．0％。此方法简便、易行，分离度较好，可作为测定塑料制品中增塑剂邻苯二甲酸酯类的方法。     

Atomic origins of solid helium bubbles in tungsten

Solid helium bubbles were directly observed in the helium ion implanted tungsten（W）, by different transmission electron microscopy（TEM） techniques at room temperature. The diameters of these solid helium bubbles range from1 nm to 8 nm in diameter with the mean bubble size about 3 nm. The selected area electron diffraction（SAED） and fast Fourier transform（FFT） images revealed that solid helium bubbles possess body-centered cubic（bcc） structure with a lattice constant of 0.447 nm. High-angle annular dark-field scanning transmission electron microscopy（HAADF-STEM）images further confirmed the existence of helium bubble in tungsten. The present findings provide an atomic level view of the microstructure evolution of helium in the materials, and revealed the existence of solid helium bubbles in materials.     

Hot corrosion behavior of the spray-formed nickel-based superalloy

An investigation of low temperature hot corrosion is carried out on a spray-formed nickel-based superalloy FGH100pre-coated with Na_2SO_4~- NaCl at 700℃ for 100 h. Mass gain measurement, x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy are used to study the corrosion behavior. Results reveal that corrosion behavior follows a sequence, that is, first rapidly proceeding, then gradually slowing down, and finally forming an outer layer composed of different types of oxides and an inner layer mainly comprised of sulfides. In-depth analysis reveals that the hot corrosion of FGH100 is a combined effect of oxidation-sulfidation and transfer of oxides.     

Controllable preparation of tungsten/tungsten carbide nanowires or nanodots in nanostructured carbon with hollow macroporous core/mesoporous shell

Large scale tungsten nanowires and tungsten nanodots are prepared in a controllable way. The preparation is based on mechanisms of chemical vapor transportation and phase transformation during the reduction of ammonium metatungstate (AMT) in H₂. The AMT is first encapsulated into the hollow core of nanostructured carbon with hollow macroporous core/mesoporous shell (NC-HMC/MS) and forms nanorods, which are the precursors of both tungsten nanowires and tungsten nanodots. Just by controlling H₂ flow rate and heating rate in the reduction process, the AMT nanorods could turn into nanowires (under low rate condition) or nanodots (under high rate condition). Besides, via heat treatment at 1200℃, the as-obtained nano-sized tungsten could convert into W₂C nanorods or WC nanodots respectively. Furthermore, the diameter of the as-obtained tungsten or tungsten carbide is confined within 50 nm by the NC-HMC/MS, and no agglomeration appears in the obtained nanomaterials.     

水解动力学拆分3-(1-萘氧基)-1,2-环氧丙烷

研究了3-(1-萘氧基)-1,2-环氧丙烷[(R,S)-1]在Salen Co(Ⅲ)催化下的水解动力学拆分(HKR)。以转化率和ee值为指标,考察了催化剂用量、底物用量、反应温度、反应时间、溶剂种类等对HKR反应的影响。最佳HKR条件为:(R,S)-1 10 mmol,w[Salen Co(Ⅲ)]=0.75%,THF 1 mL,水0.5 eq,于25℃水解40 h,(R,S)-1的转化率为49.5%,(S)-1的ee为99.5%。     

新型有机二氟化硼配合物的合成及其荧光性能

以2,4-二羟基苯乙酮为起始原料,经4步反应合成了新型的有机二氟化硼配合物:5-甲氧基.2-(2-喹啉基)苯酚二氟化硼(5),其结构经<'1>H NMR,<,13>C NMR和IR表征.UV和FL研究结果表明:5不仅具有良好的溶液荧光,也呈现明亮的固体荧光.     

中能高浓度氦离子注入对钨微观结构的影响

采用15 keV, 剂量1×10¹⁷/cm², 温度为600 ℃氦离子注入钨, 分别以块体钨研究氦离子对钨的表面损伤; 以超薄的钨透射电镜样品直接注入氦离子, 研究该条件下钨的微观结构变化, 以了解氦离子与钨的相互作用过程; 采用扫描电子显微镜、聚焦离子束扫描显微镜、透射电子显微镜、高分辨透射电子显微镜等分析手段研究氦离子注入对钨表面显微结构的影响及氦泡在钨微观结构演化中的作用.     

热敏共聚物负载的2-氨基-3-氰基-4-取代苯基-5-甲氧羰基-4H-吡喃化合物的合成

以具有热敏性能的N-异丙基丙烯酰胺及其衍生物的共聚物作载体,利用温度为相分离的控制手段,在水介质中合成了2-氨基-3-氰基-4-取代苯基-5-甲氧羰基-4H-喃化合物,其结构经^1H NMR,IR和元素分析确证。