Synthesis and Anti-inflammatory Activity of a Novel Series of 9,10-Dihydro-4H,8H-chromeno[8,7-e][1,3]oxazin-4-one Derivatives

Flavonoids exhibit a wide range of biological activities including anti-inflammatory activity,while some 1,3-benzoxazine derivatives show anti-inflammatory activity.In order to explore the novel anti-inflammatory agents,based on the principles of bioisosterism and hybridization,ten novel chromeno[8,7-e][1,3]oxazin-4-ones were synthesized and characterized with IR,1H NMR,MS and elemental analyses.The anti-inflammatory activities of the target compounds were evaluated via the croton oil-induced ear oedema tes...     

在实验室建设中深化近代物理实验教学体系改革

介绍了南开大学物理科学学院近代物理实验室通过“基地”、“211工程”和“世行贷款”等实验室建设,对近代物理实验教学体系进行改革的概况。     

熔融织构YBCO的磁性

测量了熔融织构YBCO样品从1.5K到89K的磁化曲线。磁场H平行于c轴时,在1.5K,7K和10K观察到磁通跳跃,在15—83K的温度区间观察到峰值现象。详细分析了磁化曲线和磁临界电流的各向异性。讨论了晶粒之间连接的性质和主要的钉扎中心。 关键词：     

Novel quantitative non-destructive testing method for composite structures

A novel QNDT (quantitative non-destructive testing) method is developed that is combined with a phase-shifting shearing speckle and thermograph, and, it aims at the detection of faults such as cracks, voids, delamination and weak areas. The technique is immune to ambient noise and is suitable for measuring the in situ environment. Some different depth defects that would produce deformation differing from other positions could be found with shearing speckle when the sample is loaded, however, a thermograph based on the thermal resistance effect of a defect can detect only those varisized defects embedded deeply in the composite structure by measuring the surface temperature distribution. The resolution is examined for artificial delaminated defects in carbon-fiber composite structures using a phase-shifting shearing speckle and thermograph. The experimental results have demonstrated that the technique is effective for revealing defects in composite structures.     

Y(Mn1-xCox)12磁结构的中子衍射分析

在研究Y(Mn_1-xCo_x)₁₂晶体结构的基础上,为了分析这种化合物的磁结构,我们挑选了不同成分的试样,在液氮温度下作了中子衍射测量。实验上测到的磁有序超结构峰可以用YMn₁₂单胞指标化为h十k+l=2n+1。使用各种可能的磁结构模型对数据进行了分析,根据计算强度与观测强度的最佳拟合,得出了Y(Mn_1-xCo_x)₁₂的磁结构随x变化的某些结论。 关键词：     

MnAlC永磁合金的中子衍射研究

用中子衍射技术研究了Mn_1.074Al_0.871C_0.055永磁合金的晶体结构和磁结构,Mn_1.074Al_0.871C_0.055为四角体心结构,从中子衍射谱线的拟合结果可以看出:0.992Mn和0.008C占据(0,0,0)晶位;0.082Mn、0.87lAl和0.047C占据(1/2,1/2,1/2)晶位,在不同晶位上的Mn原子的磁矩沿c轴方向反平行排列,把这些结果与Mn_1.09Al_0.91二元合金的中子衍射结果相比较,可以解释Mn_1.074Al_0.871C_0.055三元合金的磁性和机械性能都可获得明显提高的原因。 关键词：     

Effects of Different Dispersion Methods on the Microscopical Morphology of TiO2 Film

Nanocrystalline porous TiO2 films were prepared on conducting glass supports （ITO） by processed commercial TiO2 nanometre powder （P25）. Three methods of physical dispersing for TiO2 powder, i.e. grinding, magnetic stirring, sonicleaning, were used to disperse TiO2 nanometre powder. Surface morphologies of TiO2 films were observed by optic-microscope and SEM. It is found that the surface morphologies of TiO2 films are determined not only by the dispersing methods but also by the percentage of TiO2 powder in the dispersing system. Different film morphologies can be obtained under the same preparation condition but with different dispersing methods. A lot of cracks exist on the film surface for which the TiO2 slurry is dispersed by grinding. Magnetic stirring leads to some white points and micro-holes on the film surface. Only a few of micro-holes can be observed on the film surface, in which the TiO2 slurry is dispersed by sonicleaning. Different surface morphologies can also be found with different thicknesses of TiO2 films. Different film thicknesses are due to different percentages of TiO2 powder in the slurry. The related mechanism leading to different features of the surface morphologies for the TiO2 films is discussed.     

Influence of Deviation on Optical Transmission through Aperiodic Superlattices

We propose a deviation model and study the influences of the relative error and sensitivity of a machine on the transmission coefficients （TCs） of Fibonacci superlattices. It is found that for a system with fewer layers, the influence of deviation can be ignored. When superlattices become more complicated, they may be fabricated by a machine with suitable relative error and possess the designed value of TO. However, when the number of system layers exceeds some critical value, superlattices should be manufactured only by precise machines. The influence of the sensitivity is also discussed.     

19F-NMR进展

19F-NMR技术由于其化学位移范围大、不易出现峰重叠及灵敏度高等优点,自上个世纪50年代出现以来,在分析光学异构体,生命科学等研究中有其特殊意义.在体内核磁共振技术中,19F-NMR与其他方法相比,在不损伤样品的条件下,就可进行实时定量监测.近30年,引人氟代指示剂进行体内19F-NMR的研究,含氟生物活性物质以及含氟材料的研究受到很大的重视,19F-NMR技术及其应用发展起来.从近10年的情况来看,含氟生物活性物质的研究以及在医药、农药和具有优异性能的含氟材料的研究应用受到很大的重视,这是近期19F-NMR研究发展的一个主要特点.