Synthesis, structure and fluorescence properties of a highly stable indium(III)-2,5-pyridinedicarboxylate coordination polymer

The hydrothermal reaction of 2,5-pyridinedicarboxylic acid (H₂PDC), diethylene triamine and In(NO₃)₃·4.5H₂O gave rise to a two-dimensional (2D) coordination polymer In(OH)(2,5-PDC). This compound crystallizes in the orthorhombic space group Iba2, with cell parameters, a = 12.656(3) Å, b = 20.114(4) Å, c = 6.2216(1) Å, V = 1583.9(5) Å³ and Z = 8. Its structure contains one-dimensional In–O–In–O– chains, which are further linked by 2,5-PDC ligands into a 2D supramolecular neutral framework. The adjacent 2D layers are parallel with each other and construct a three-dimensional framework via hydrogen bands. At room temperature, the compound exhibits intense photoluminescence. On the basis of the results of TG/DTA analyses, the structure is thermally stable up to 390 °C.     

WCDMA的MBMS技术

主要介绍了基于WCDMA的MBMS技术,给出了其网络架构和技术难点,并对其应用给无线网络带来的影响作了一定深度的探讨。     

安徽省旱涝急转规律的认识与研究

旱涝急转是指某一地区或某一流域发生较长时间干旱时，突遇集中强降雨，引发山洪暴发、河水陡涨．客水入侵、内水难以及时外排的一种自然现象。旱涝急转极易造成人员伤亡、水库垮坝等重大经济损失。在防汛抗旱中，安徽省要充分认识旱涝急转的危害性，加强应急管理，具体包括思想上保持高度的警觉，加快防汛抗旱工程体系和预测预警体系建设，有效应对旱涝急转。     

不同压力下气层岩样m、n值变化的实验研究

胶结指数m和饱和度指数n变化规律的研究一直是岩石物理学家和测井解释分析家关注的问题。压力是影响m、n的重要因素,但迄今为止,仍未取得可使多数人接受的一般性结论。实验开展了低孔隙度低渗透率气层岩样在不同压力条件下的电阻率测量,在考虑孔隙度随压力变化的基础上建立了m、n参数随压力变化的关系,得出结论:某些地区的气层岩样在压力增大时即使考虑孔隙度变化,m值增大,n值减小。     

Densitometry determination of dioxins using gold nanoparticlemodified dioxin response element probes

This study aims to develop a rapid and sensitive densitometry bioassay of dioxins. It is known that dioxin ligand can bind heterodimeric aryl hydrocarbon receptor (AhR) and trigger the formation of the complex of dioxin-AhR, AhR nuclear translocator (Arnt), and dioxin-responsive element (DRE). We have established a rapid and sensitive method using nanoparticle-modified DRE probes based on dioxin-dependent binding of DRE to AhR complex. Dioxins can trigger the binding of nanoparticle-modified DRE probe to AhR complex. The nanoparticle-modified DRE probes in the dioxin-AhR-Arnt-DRE complexes immobilized on the microplates were detected by measuring optical density after silver enhancement. Results showed that as little as 0.01 pM of TCDD could be detected. Dioxins could be quantified accurately with the linear range from 1 nM to 0.01 pM. The coefficient of variation was 5≈8% in this bioassay. The optical density of nanoparticle-based silver enhancement was produced in a dose- and time- dependent manner. The dioxin concentrations in fly ash samples determined by this bioassay were comparable with that by the standard HRGC/HRMS. Thus this bioassay is a sensitive and convenient cell-free bioassay of dioxin that is suitable for screening of dioxins in environmental or food matrices.     

New concept of surface modification to LiCoO2

As the continuance of our series study on LiCoO₂ surface modification, the complicated traditional surface coating method is replaced with simple addition of amorphous YPO₄ and Al₂O₃ in commercial LiCoO₂ or in commercial electrolyte based on our understanding to the improvement mechanism of surface modification. Comprehensive studies by X-ray photoelectron spectroscopy (XPS), gas chromatography and mass spectroscopy (GC–MS), inductively coupled plasma (ICP) and Fourier transformed infrared (FTIR) indicate that the products of spontaneous reaction between the additive and the LiPF₆ based electrolyte are responsible for the performance improvements.     

Si衬底上横向外延GaN材料的微结构和光学性质的研究

用氢化物气相外延 (HVPE)方法在Si(III)衬底上成功横向外延生长出晶体质量较好的GaN薄膜材料。透射电子显微镜 (TEM )的研究结果表明 ,横向外延区域GaN的位错密度明显减小。由于SiO2 掩膜腐蚀角的不同 (分别为 90°和 6 6°) ,导致了横向外延GaN材料一些独特的微观形貌。微区拉曼光谱由数百条拉曼散射曲线组成 ,每一条曲线有三个振动模 ,分别对应Si振动模式 (5 2 0cm- 1) ,E2 模式 (5 6 6cm- 1)和E1(LO)模式(732cm- 1)。在垂直条纹方向 ,峰位和峰宽没有明显的变化 ,而峰强约 5 μm会发生周期性变化     

基于DWT的数字音频水印技术研究

提出了一种基于小波变换的多分辨率数字水印隐藏与检测新算法,算法的优点在于其算法简单。利用小波变换的快速、简单和多分辨率特点,将水印信号隐藏在第1、2、3级的详细分量(细节信号)中保证了水印的稳健性,具有很强的抵御各种信号处理变换的能力,适用于数字语音等信号的版权保护。最后给出了计算机仿真实验结果,证明了本算法的有效性。     

制冷剂充灌量和毛细管长度对空调系统性能的影响

在空调器的匹配中，制冷剂充灌量和毛细管长度是两个非常关键的因素。本文采用理论与数值计算的方法，对制冷剂充灌量和毛细管长度对空调系统性能的影响进行了分析，为空调器的优化设计匹配、提高空调器的性能奠定了基础。     

混合非淀粉多糖水解酶酶活测定方法的改进

用分光光度法分别准确测定了混合非淀粉多糖水解酶预混样中木聚糖酶、果胶酶、β－葡聚糖酶和纤维素酶的酶活。将酶以0．1％的比例添加到饲料中后，除木聚糖酶外，其余三种酶的酶活无法准确测定出来，于是对酶活测定方法进行了改进，利用凝胶过滤色谱法对酶液进行预处理，排除了体系中还原糖等小分子量杂质的干扰；采用琼脂放射扩散法测定纤维素酶或β-葡聚糖酶酶活，提高了测定的特异性和灵敏度；利用专一性的酸性醋酸铜法测定果胶酶酶活，提高了特异性；采用硫酸铵沉淀法处理木聚糖酶，可排除另的酶对木聚糖酶酶活测定的干扰。