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%。     

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.     

表面等离子体共振技术测定畜禽肉中泰乐菌素含量

建立了一种基于表面等离子体共振(SPR)技术测定畜禽肉中泰乐菌素残留的新方法.用传感芯片(Sensor chips CM5),以25%ACN-0.25 moL/L NaOH为再生溶液,HBS-EP为缓冲溶液,流速为40 μL/min,运用表面等离子体共振(SPR)技术测定畜禽肉中泰乐菌素的含量,结果表明泰乐菌素在32 ng/mL范围内,在Sensor chips CM5表面所产生的相对共振强度与质量浓度有良好的响应关系,平均回收率为80.0%～99.5%,RSD为2.0%～4.7%,检出限为0.03 ng/mL.该方法简便、灵敏,可以为产品的安全与质量控制提供快速分析方法.     

有机高价碘盐参与的炔丙醇的交叉偶联反应

有机高价碘在钯（Ⅱ）／铜（Ⅰ）共催化作用下与炔丙醇发生交叉偶联反应生成3－取代炔丙醇。该反应不仅条件温和，产率很高，而且具有良好的区域选择性。所得产物均经熔点，IR及^1H NMR验证。     

高效液相色谱法测定大黄酸的含量

建立了测定大黄酸含量的高效液相色谱方法。分析柱为Waters symmetry C18色谱柱(150 mm×4.6 mm,5μm),流动相为甲醇-水-冰乙酸(70∶30∶2,体积比),流速0.8 mL.min-1,检测波长为254 nm,回收率为99.4%~100.2%,用于原料(掌叶大黄)和产品(大黄酸)的质量控制,同一天对大黄酸标准溶液连续测定和每隔1 h进样一次测定(n=6)的相对标准偏差为0.6%~0.8%。经测定原料(掌叶大黄)中大黄酸的质量分数为0.58%,产品中大黄酸的质量分数为73.1%~90.4%。     

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.     

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.     

调控有机小分子晶体力致发光行为的方法

尽管力致发光(mechanoluminescence, ML)现象的发现至今已有超过400年的历史, 但直到最近几十年才再次走入人们关注的视野. 这种与分子堆积关系密切的固体光学现象已经在光电材料领域内得到了一些应用, 并蕴藏着巨大的开发前景. 近年来, 随着有机功能化合物的蓬勃发展, 对力致发光材料的探索已逐渐从无机与高分子化合物、有机金属配合物、陶瓷等方面转到纯有机小分子晶体. 此外, 随着人们对有机小分子力致发光活性晶体认识的不断深入, 该领域的研究兴趣也从最初的如何获得此类晶体变为如何调控晶体的力致发光行为从而使其呈现出ML性能的差异. 本综述将对一些调控有机小分子晶体力致发光性能的手段, 例如物理方法、手性活化、分子结构改造、主客体掺杂、同质多晶形成等进行总结, 同时也将分子堆积与分子间相互作用对晶体发光性能的影响进行探讨, 并在此基础上对有机小分子力致发光晶体研究领域的未来发展提出建设性的展望.     

O-对甲氧基苯基-N,N-二苄基酪氨酸乙酯的合成

N,N-二苄基酪氨酸乙酯(2)与对溴苯甲醚(3)经偶联反应合成了O-对甲氧基苯基-N,N-二苄基酪氨酸乙酯,其结构经NMR,IR和MS表征。最佳反应条件为:210mmol,n(2)∶n(3)∶n(K3PO4)∶n(CuSO4.5H2O∶n(N,N-二甲基甘氨酸盐酸盐)=1.0∶1.3∶1.3∶0.2∶0.35,在DMF(50mL)中于100℃反应8h,产率54.7%,93.8%ee。