Multi-walled carbon nanotubes supported Cu-doped ZnO nanoparticles and their optical property

Multi-walled carbon nanotubes (MWNTs)/Cu-doped ZnO composite powders were prepared by co-precipitation method, and were characterized by X-ray diffraction, electron microscopy, fluorescence spectrum, and ultraviolet spectrum. Experimental results show that the MWNTs can be modified by Cu-doped ZnO nanoparticles with hexagonal wurtzite structure after annealed at 450?°C, and the nanoparticle size is about 15?nm. Two ultraviolet (UV) peaks and a green band centered at about 510?nm are observed in the fluorescence spectrum of MWNTs/Cu-doped ZnO composite powder annealed at 450?°C. Furthermore, MWNTs and Cu doping significantly improve the UV absorption ability of ZnO.     

离轴非球面镜精磨阶段的三坐标检测技术

提出了使用三坐标测量机（CMM）对离轴非球面镜进行测量的方法。通过CMM对离轴非球面镜镜面进行自动测量,获得实际面形的三维坐标数据,并与理论离轴非球面镜模型进行分析比较,得到实际镜面的面形误差值和均方根值; 依据CMM的测量结果,完成了对离轴非球面镜精磨阶段的加工,解决了目前离轴非球面镜精磨阶段难于检测,以至于无法加工的问题。随着离轴非球面镜顺利进入抛光阶段,使用CMM实现了离轴非球面镜精磨检测与抛光检测的无缝对接。     

Novel multifunctional optical device with only axial material parameter spatially variant

Based on the concept of complementary media and theory of coordinate transformation,a novel kind of optical device,exhibiting the multiple performances of a complementary cloak and a transparent device,is proposed.Only the axial material parameter of the proposed device is spatially variant,and the transverse material parameters are constant.The multiple functions of the proposed device are validated by full wave simulations.In addition,the effects of loss and parameter perturbations on the performances of the device are also investigated.These results can be used in field of antenna protection and other electromagnetic field engineering.     

WIMPs search by scintillators: possible strategy for annual modulation search with large-mass highly-radiopure NaI(TI)

The DAMA experiments are running deep underground in the Gran Sasso National Laboratory. Several interesting results have been achieved so far. Here a maximum likelihood method to search for the WIMP annual modulation signature is discussed and applied to a set of preliminary test data collected with large mass highly radiopure NaI(Tl) detectors. Various related technical arguments are briefly addressed.     

Effect of annealing temperature and annealing atmosphere on the structure and optical properties of ZnO thin films on sapphire (0 0 0 1) substrates by magnetron sputtering

ZnO thin films were epitaxially grown on sapphire (0 0 0 1) substrates by radio frequency magnetron sputtering. ZnO thin films were then annealed at different temperatures in air and in various atmospheres at 800 °C, respectively. The effect of the annealing temperature and annealing atmosphere on the structure and optical properties of ZnO thin films are investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL). A strong (0 0 2) diffraction peak of all ZnO thin films shows a polycrystalline hexagonal wurtzite structure and high preferential c-axis orientation. XRD and AFM results reveal that the better structural quality, relatively smaller tensile stress, smooth, uniform of ZnO thin films were obtained when annealed at 800 °C in N₂. Room temperature PL spectrum can be divided into the UV emission and the Visible broad band emission. The UV emission can be attributed to the near band edge emission (NBE) and the Visible broad band emission can be ascribed to the deep level emissions (DLE). By analyzing our experimental results, we recommend that the deep-level emission correspond to oxygen vacancy (V_O) and interstitial oxygen (O_i). The biggest ratio of the PL intensity of UV emission to that of visible emission (I_NBE/I_DLE) is observed from ZnO thin films annealed at 800 °C in N₂. Therefore, we suggest that annealing temperature of 800 °C and annealing atmosphere of N₂ are the most suitable annealing conditions for obtaining high quality ZnO thin films with good luminescence performance.     

PSⅡ颗粒二聚体中类胡萝卜素向反应中心传能研究

运用瞬态荧光光谱技术在77 K低温下对PSⅡ颗粒复合物中类胡萝卜素（Car）分子的能量传递过程进行研究, 通过不同激发波长473 nm, 481 nm, 507 nm选择性激发PSⅡ颗粒复合物中色素分子, 得到PSⅡ颗粒二聚体中关于Car能量传递的三组时间组分：16.6 ps, 130~183 ps, 217~249 ps. 其中16.6 ps反映了LHCⅡ中的Car分子将能量通过中间体Cars、Chls分子传递到Chl639的过程; 130~183 ps为核心天线中的β-Car分子向RC的能量传递时间; 217~249 ps为LHCⅡ中Car481通过中间Chla分子向RC的传能时间.     

黑腔中等离子体相互作用的流体力学现象观测

激光间接驱动惯性约束聚变实验中,黑腔内情况复杂,在激光烧蚀和辐射烧蚀等的驱动下,光斑区、冕区、纯辐射烧蚀区、射流区的多种等离子体以不同规律运动.发展了X光双能段窄能带的时间分辨成像方法,用以观测黑腔内多种等离子体的运动情况.在真空黑腔中观测到清晰的射流,分析了射流产生机制及其速度;在黑腔中充气,能有效消除射流和抑制冕区等离子体运动,但两种物质界面处可能会出现流体力学不稳定性等现象,分析了界面处的压力平衡关系和密度陡变情况.     

Inhibitory Effects and Mechanism of the Natural Compound Diaporthein B Extracted from Marine-Derived Fungi on Colon Cancer Cells

This study aimed to investigate the inhibitory effects and mechanism of diaporthein B (DTB), a natural compound extracted from the fungus Penicillium sclerotiorum GZU-XW03-2, on human colon cancer cells. The inhibitory effect of DTB at different concentrations on the proliferation of colon cancer cells HCT116 and LOVO was detected at 24 and 48 h. The effect of cell migration and clone formation ability were detected by cell scratch and plate cloning experiments. Morphological changes were observed by Hoechst 33342 and Annexin-V/PI staining, and flow cytometry was used to detect the proportion of apoptotic cells. DTB significantly inhibited colon cancer cell proliferation, migration, and apoptosis in a dose-dependent manner without significant effects on normal colonic epithelial cells NCM460. The IC50 inhibition effect can be achieved after treatment with 3 μmol/L DTB for 24 h. Compared with the blank group, the migration and clonal-forming ability of colon cancer cells in the DTB group was significantly decreased (p < 0.01), while the apoptotic cells were significantly increased (p < 0.01) in a concentration-dependent manner. DTB can inhibit the proliferation and migration of human colon cancer cells HCT116 and LOVO and promote the apoptosis of human colon cancer cells.     

二维材料在光催化二氧化碳还原中的研究进展

近几十年来,由温室效应所导致的气候变暖、海平面上升等环境问题日趋严重,科学家们一直致力于研究可高效转化二氧化碳(CO2)等温室气体的技术.以太阳能为驱动力的光催化技术,可将CO2转化成甲烷、甲醇、甲酸或C2+等高附加值的碳氢燃料,同时缓解温室效应和能源危机.二维(2D)材料因具有超大的比表面积和独特的电子结构,在光催化...     

加强实验教学研究 培养学生创造思维

化学教学中实施创造教育,要特别加强实验教学研究.本人的做法是挖掘实验教学与创造思维培养的结合点,诱导学生创造思维;创设教学氛围,激发学生创造思维;加强实验创新,训练学生创造思维.