ABSTRACT
Monolayer Cu2S and ZnO, and three kinds of complex films, Cu2S/ZnO, ZnO/Cu2S, and ZnO/Cu2S/ZnO, were deposited on glass substrates by means of radio frequency (RF) magnetron sputtering device. The impact of the thickness of ZnO and Cu2S on the whole transmittance, conductivity, and photocatalysis was investigated. The optical and electrical properties of the multilayer were studied by optical spectrometry and four point probes. Numerical simulation of the optical transmittance of the multilayer films has been carried out in order to guide the experimental work. The comprehensive performances of the multilayers as transparent conductive coatings were compared using the figure of merit. Compared with monolithic Cu2S and ZnO films, both the optical transmission property and photocatalytic performance of complex films such as Cu2S/ZnO and ZnO/Cu2S/ZnO change significantly.
ABSTRACT
ZnO light-emitting diodes (LEDs) have an enormous potential in lighting applications. The major issue to be resolved is the generating and control of light emissions. This issue arises from the variation and combination in LED wavelength. We found that defect luminescence of ZnO has a varied wide range of wavelength, which suits to an application of LED for white-light generation. We have shown both experimentally and theoretically that defect emission can be used in ZnO systems. This type of defect has the advantage of not requiring extensive and costly factory systems comparing with traditional doped materials and others. We not only propose potential application of native defect luminescence of Zinc Oxide film for white LEDs-flat light sources, but also have some methods to control defect origins, a certain center position and broad range of the emission band of ZnO film in the initial stage. According to different preparing method and certain experiment conditions, variant white such as whitish and bluish-white etc., primary and important colors- blue bands (455, 458 nm), green bands (517, 548 nm), red bands (613, 569 nm) are obtained respectively. This proved that it is a better road to one white light LED with one kind of material -ZnO.
ABSTRACT
Complex ZnO compound material has great potential applications for optoelectronic devices. In this article, we give report to a simulation growth of a kind of special"fruiting ball"natural "Platanus Occidentalis" made of Al2O3, Au and ZnO. The surface of "Platanus Occidentalis " has numerous tiny Au seeds on the surface of Al2O3 ball. ZnO needles synthesized by the electrodeposition technique grow well on the Au seed layer. The obtained mono dispersive needles (or hexagonal columns) have different distribution density. The prepared sample looks like the assembled "Platanus Occidentalis" in photographs of scanning electron microscopy (SEM). Photoluminescence (PL) of samples at 6 K temperature and other characteristics are investigated. The appearance of sharp bound exciton (BE) emission line and the longitudinal optical (LO)-phonon replicas imply that the ZnO nanocolumns are of high optical quality.
ABSTRACT
Vanadium oxide films were deposited at different substrate temperatures up to 400 degrees C by DC magnetron sputtering, and through the method of the X-ray diffraction, electron scanning microscopy, infrared and Raman spectra, the present paper studies the structure properties of those films, and through the method of spectrum measuring and fitting, this paper studies the optical properties of the films. At low temperature of preparation the optical films have high optical transmittance. The films prepared at low substrate temperature (lower than 200 degrees C) have amorphous structure and some films prepared at high substrate temperatures (higher than 200 degrees C) have polycrystalline structure. The films' optical parameters were achieved by using classic model to fit the characteristic of transmittance.
ABSTRACT
OBJECTIVES: This study explored the expression and function of Slug in human extrahepatic hilar cholangiocarcinoma (EHC) to identify its role in tumor progression. METHODS: The expression of Snail and Slug mRNA in 52 human tissue samples of EHC was investigated. The mRNA of Snail and Slug were quantified using reverse transcriptase-PCR, and correlations with E-cadherin expression and clinicopathological factors were investigated. We then investigated transfection of Slug cDNA in endogenous E-cadherin-positive human EHC FRH0201 cells, selectively induced the loss of E-cadherin protein expression, and then small interfering RNA (siRNA) for inhibition of Slug expression in endogenous Slug-positive human EHC QBC939 cells, selectively induced the loss of Slug protein expression. A Boyden chamber transwell assay was used for invasion. RESULTS: Slug mRNA was overexpressed in 18 cases (34.6%) of EHC compared with adjacent noncancerous tissue. E-Cadherin protein expression determined in the same 52 cases by immunohistochemistry was significantly down-regulated in those cases with Slug mRNA overexpression (P = 0.0001). The tumor and nontumor ratio of Slug mRNA was correlated with nodal metastasis(p = 0.0102), distant metastasis (p = 0.0001)and Survival time(p = 0.0443). However, Snail mRNA correlated with neither E-cadherin expression nor tumor invasiveness. By inhibiting Slug expression by RNA interference, we found that reduced Slug levels upregulated E-cadherin and decreased invasion in QBC939 cell. When the QBC939 cells was infected with Slug cDNA,, significant E-cadherin was downregulated and increased invasion in QBC939 cell. CONCLUSIONS: The results suggested that Slug expression plays an important role in both the regulation of E-cadherin expression and in the acquisition of invasive potential in human EHC. Slug is possibly a potential target for an antitumor therapy blocking the functions of invasion and metastasis in human EHCs.
