新型喹唑啉衍生物的设计、合成及体外抗肿瘤活性

为了寻找高效、毒性小的抗肿瘤药物,设计并合成了一系列新型的喹唑啉衍生物,其结构经¹H NMR、 ¹³C NMR、 IR、 MS（ESI）和元素分析表征。采用细胞增殖抑制实验法（MTT法）测定了化合物3a～10c对人盲肠腺癌细胞（HCT-8）、人肝癌细胞（HepG2）、人肺癌细胞（A549） 和人高转移性肝癌细胞（MHCC-97H）的体外抑制活性。结果表明：4-位为氨基苯甲基丙二酸二甲酯时（3a~6c）,化合物的肿瘤抑制作用比其相应水解产物（7a~10c）更强;氨基在苯甲基丙二酸二甲酯间位时,抑制活性明显优于对位取代。其中,5c对HCT-8、 A549及MHCC-97H的抑制活性较显著,IC₅₀值分别为13.613 μmol/L, 13.578 μmol/L和25.804 μmol/L。      

引力的曲率平方理论

利用法坐标对局部等效原理、以及局部等效原理在构造曲率平方可重整拉氏量中的作用进行了论证．得到了曲率平方引力的场方程、其线性近似以及有质引力粒子的Ｙｕｋａｗａ势的表式．     

Strong-Superstrong Transition in Glass Transition of Metallic Glass

Dynamic fragility of bulk metallic glass （BMG） of Zr64Cu16Ni10Al10 alloy is studied by three-point beam bending methods. The fragility parameter mfor Zr64Cu16Ni10Al10 BMG is calculated to be 24.5 at high temperature, which means that the liquid is a ＂strong＂ liquid, while to be 13.4 at low temperature which means that the liquid is a ＂super-strong＂ liquid. The dynamical behavior of Zr64Cu16Ni10Al10 BMG in the supercooled region undergoes a strong to super-strong transition. To our knowledge, it is the first time that a strong-to-superstrong transition is found in the metallic glass. Using small angle x-ray scattering experiments, we find that this transition is assumed to be related to a phase separation process in supercooled liquid.     

Evaporation-coupled wetting of ZrO2 by molten Mg in Ar atmosphere

The wetting behaviors of molten Mg drops on polycrystalline ZrO₂ substrate surfaces were studied in a controlled Ar atmosphere at 948–1173 K using an improved sessile drop method. The ZrO₂ substrate is virtually not wetted by molten Mg at temperatures below 1173 K. The wetting and evaporation stages according to different variation behaviors of contact angle, contact diameter and drop height were identified. Six representative modes were proposed to describe the evaporation-coupled wetting behaviors during different stages. The competitions between surface oxidation, chemical reaction and drop evaporation were discussed to account for the mechanisms for various wetting behaviors at different temperatures. The chemical reaction leads to the formation of more wettable MgO phase at the interface; however, it yields only an inconspicuous improvement in the wetting due to enhanced Mg evaporation.     

Growth and spectroscopic characterization of Er: Sr3Y(BO3)3 crystal

This paper reports the growth and spectroscopic characterization of Er³⁺:Sr₃Y(BO₃)₃ crystal. Er³⁺:Sr₃Y(BO₃)₃ crystal with dimensions up to ∅20×35 mm³ has been grown by Czochralski method. The polarized spectroscopic properties of Er³⁺:Sr₃Y(BO₃)₃ crystal were investigated. Based on the Judd-Ofelt theory, the effective intensity parameters Ω_t were obtained: Ω₂=1.71×10⁻²⁰ cm², Ω₄=1.39×10⁻²⁰ cm², Ω₆=0.74×10⁻²⁰ cm² for π-polarization, and Ω₂=1.77×10⁻²⁰ cm², Ω₄=1.44×10⁻²⁰ cm², Ω₆=0.65×10⁻²⁰ cm² for σ-polarization. The emission cross-section σ_em was calculated to be 4.75×10⁻²¹ cm² for π-polarization at 1536 nm and 6.30×10⁻²¹ cm² for σ-polarization at 1537 nm. The investigated results showed that Er³⁺:Sr₃Y(BO₃)₃ crystal may be regarded as a potential laser host material for 1.55 μm IR solid-state lasers.     

Photoluminescence properties of various CVD-grown ZnO nanostructures

We have studied systematically room-temperature photoluminescence (PL) properties of many nanostructured ZnO samples grown by chemical vapour deposition (CVD). Their PL spectra consist of two emissions peaked in the ultraviolet (UV) and green regions. The relative intensity of these emissions depends on the excitation energy density, size and morphology of ZnO nanostructures. Based on the excitation-density dependence of the integrated intensity ratio of UV-to-green emission, we could classify PL spectra of ZnO nanostructures into three groups characteristic of size and morphology. Our study also reveals that with increasing excitation density, the UV-peak position shifts slightly towards longer wavelengths while the green emission around 514-520 nm is almost unchanged. This green-luminescence emission is dominant when the nanostructure sizes range from 20 to 200 nm, which is related to a large surface-to-volume ratio.     

Investigation of nonvolatile holographic storage in LiNbO3:Mn:Ce:Fe crystal

We investigate the persistent holographic recording in triply doped LiNbO₃:Mn:Ce:Fe crystals at different oxidation/reduction states. The experimental results show that there is an optimum oxidation/reduction state, which results in the best dynamic range M/#. Compared with doubly doped LiNbO₃:Ce:Fe, we found that the nonvolatile diffraction efficiency and the best dynamic range M/# obtained in triply doped samples are larger than that obtained in doubly doped samples. The reason for the increase of the crystal about the nonvolatile diffraction efficiency and the dynamic range M/# was also explained.     

Holographic storage stability in PQ-PMMA bulk photopolymer

Holographic storage stability is investigated experimentally in phenanthrenequinone (PQ) doped poly-(methyl methacrylate) (PMMA) photopolymer with high thickness and rigid polymer matrix. It is demonstrated that the stability consists of two continuous processes, dark enhancement and decay of holograms, which are corresponding to the diffusion of PQ and its photoproduct molecules, respectively. During dark enhancement the Bragg detuning of angle selectivity is observed. Therefore it is necessary to obtain steady holograms quality by adjusting the readout angle. After reaching steady state, the long-term stability of holograms is determined by the diffusion of photoproducts. Temperature is a most significant parameter for long-term stability, which can bring sufficient energy to increase the diffusion of photoproducts and reduce the stability. Finally low temperature and uniform exposure as alternative methods are proposed to optimize the storage stability after dark enhancement. Moreover the influence of humidity on the storage stability is neglectable.     

Synthesis, field emission and glucose-sensing characteristics of nanostructural ZnO on free-standing carbon nanotubes films

Free-standing multiwall carbon nanotubes (MWNTs) films were coated, using chemical vapor deposition method, with a thin layer of nanostructural ZnO. The morphology and crystal structure of the as-grown products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman scattering analyses. Field emission (FE) results demonstrated that the needle-like and spherical ZnO-MWNTs composite structure films possessed good performance with a turn-on field of 1.3, 2.2 V μm⁻¹ and a threshold field of 2.6, 4.5 V μm⁻¹, respectively. The glucose-sensing characteristic has also been studied. The multi-layer electrode (PDDA/GOx/ZnO/MWNTs) exhibited significant electrocatalysis to the oxidation and reduction of H₂O₂ than the PDDA/GOx/MWNTs electrode, which provided wide potential applications in clinical, environmental, and food analysis.     

被动声纳信号检测技术研究

论文介绍了被动声纳工作原理及被动声纳信号的检测原理,分析了采用Chirp—z变换进行频谱细化的方法,并使用Matlab进行仿真。仿真结果表明,Chirp-z变换可使频谱细化,提高局部频段内的分辨能力。采用该算法对被动声纳检测线谱进行处理,使系统的整体检测性能有较大的提高。