One‐ and Two‐Dimensional PbII Complexes Constructed from N‐Donor Chelating Ligands with Extended π‐System and Organic Dicarboxylates

Two new coordination polymers [Pb(TIP)(1,3‐bdc)]_n ( 1 ) and [Pb(Dpq)(fum)]_n ( 2 ) (TIP = 2‐(2‐thienyl)imidazo[4,5‐f]1,10‐phenanthroline, Dpq = dipyrido[3,2‐d:2′,3′‐f]quinoxaline, 1,3‐H₂bdc = benzene‐1,3‐dicarboxylic acid, fum = fumaric acid) were synthesized by hydrothermal reactions and were characterized by elemental analyses, IR spectroscopy and single‐crystal X‐ray diffraction. Complex 1 is a one‐dimensional (1D) chain, which is bridged by 1,3‐bdc ligands. This is further extended into a three‐dimensional (3D) supramolecular structure by hydrogen bonding interactions. Compound 2 exhibits a two‐dimensional (2D) network structure, which is further stacked by π–π interactions to form a 3D supramolecular framework. The most important feature of these two complexes is that the N‐donor ligands with an extended π‐system play a crucial role in the formation and stabilization of the final supramolecular frameworks. Moreover, the fluorescence property of complex 1 was also investigated in the solid state at room temperature.     

J/ψ→Σ~0 “非汉字符号”~0 衰变研究(英文)

利用北京正负电子对撞机 (BEPC)上的北京谱仪 (BES)收集的 7 8× 1 0 6 个J ψ事例 ,研究了J ψ→Σ0 Σ0 衰变 .其衰变分支比为BR(J ψ→Σ0 Σ0 ) =( 0 97±0 0 4± 0 2 4 )× 1 0 - 3,角分布具有 dNdcosθ=N0 ( 1 +αcos2 θ)的形式 ,α值等于 -0 2 1± 0 2 7± 0 1 3 .     

掺Sn的纳米TiO2表面光生束缚激子的验证及其特性

采用溶胶-凝胶法制备了不同掺杂Sn的TiO2纳米粒子，并主要利用表面光电压谱(SPS)和电场诱导表面光电压谱(EFISPS)对样品进行了表征，重点探讨了焙烧温度和掺Sn量对TiO2光生电荷性质的影响．同时揭示了样品结构与表面光生束缚激子的关系及其特性．结果表明：与束缚激子相关的光伏响应只在含有金红石相的TiO2样品中出现，且在混晶相中表现得更加显著．掺杂适量Sn不仅提高了纳米TiO2的与带带跃迁相关的SPS响应强度，同时也使与束缚激子相关的SPS响应明显增强．     

担载铂催化剂用于硝基苯催化加氢制对氨基苯酚的研究

研究了以活性炭、γＡ１２Ｏ３、γ－Ａ１２Ｏ３－ＴiＯ２为载体,用浸渍法制备的铂含 量为１％的担载铂催化剂,用于硝基苯催化加氢制对氨基苯酚。发现Ｐｔ／γ－Ａ１２Ｏ３－ＴiＯ２催化剂有较高的活性、选择性和较长的寿命,催化剂循环使用１０次后,对氨基酚的率仍高于８０％,优于常用的Ｐt／Ｃ催化剂 。测定了催剂的比表面积、孔结构以 及活性金属铂的分散度,发现孔结构与催化剂性能之间没有规律性的关系;而铂在γ－Ａ１２     

Recognition of 6-benzyladenine using a molecularly imprinted membrane on a cellulose acetate support

A molecularly imprinted polymer membrane was prepared on a cellulose acetate support by the photopolymerization of methacrylic acid and a cross linker, ethyleneglycol dimethacrylate, in the presence of the template molecules of 6-benzyladenine (BA). The polymeric membrane morphologies were visualized by scanning electron microscopy and its selectivity was evaluated by a permeation test. The association ratio and apparent association constant of the complex formed between the methacrylic acid and BA were determined by cyclic voltammetry, and are 1 : 1 and 204.9, respectively. These results indicated that there existed some complementary cavities on the imprinted membrane corresponding in size, shape, and functional groups to the template molecules of BA. Hence, the imprinted membrane was able to recognize BA. It is predicted that this molecularly imprinted membrane may be applicable to the assay of BA or for the preparation of a molecularly imprinted polymer sensor for the determination of BA in plant samples. The text was submitted by the authors in English.     

Influence of substrate temperature on electrical and optical properties of p-type semitransparent conductive nickel oxide thin films deposited by radio frequency sputtering

Nickel oxide thin films were deposited on fused silica and Si(1 0 0) substrates at different substrate temperatures ranging from room temperature to 400 °C using radio frequency reactive magnetron sputtering from a Ni metal target in a mixture of O₂ and Ar. With the increase of substrate temperature, nickel oxide films deposited on the Si substrates exhibit transition from amorphous to poly-crystalline structures with different preferred orientations of NiO(2 0 0) and (1 1 1). The films deposited at higher temperature exhibit higher Ni²⁺/Ni³⁺ ratio. With substrate temperature increasing from room temperature to 400 °C, the electrical resistivities of nickel oxide films increase from (2.8 ± 0.1) × 10⁻² to (8.7 ± 0.1) Ω cm, and the optical band-gap energies increase from 3.65 to 3.88 eV. A p-nickel oxide/n-zinc oxide heterojunction was fabricated to confirm the p-type conduction of nickel oxide thin film, which exhibited a steadily rectifying behavior.     

In situ observation of β‐BaB2O4 microcrystal growth in glass matrix

The morphological evolution and growth mechanism of β‐BaB₂O₄ microcrystal in Li₂B₄O₇‐BaB₂O₄ glass (Li₂O‐B₂O₃‐BaO) matrix were investigated by optical in situ observation method. And the crystallization temperature T_c has been examined by differential thermal analysis (DTA). It demonstrates that homogeneous distribution of hexagonal shaped BBO microcrystals with size up to several tens of microns is typical when temperature is much higher than T_c, however, heterogeneous nucleation occurs when annealing temperature is close to T_c. For the latter case, crystal clusters that consist of several microcrystal grains are obvious. When the crystals in one specific cluster grows larger, crystal motion occurs in glass matrix while their orientation and symmetrical shape keep nearly no changes. Additionally, the BBO microcrystal has been determined to grow nearly in linear with time, which suggests a mechanism of interface‐controlled growth. Furthermore, the activation energy of BBO crystal growth in glass matrix is calculated which is around 2.4 eV. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Mechanism of Current Oscillations in Gallium ArsenidePhotoconductive Semiconductor Switches

Semi-insulating photoconductive semiconductor switch with an electrode gap of 4 mm, triggered by a laser pulse with energy of 0.5md, and applied bias of 2.5kV, the periodicity current oscillation with a cycle of 12ns is obtained. It is indicated that the current oscillation is one mode of transferred electron effect, namely quenched domain mode. This mode of trans-electron oscillator is obtained when the instantaneous bias electric field drops below the sustaining field （the minimum electric field required to support the domain） before the domain reaches the anode, which leads to the domain disappears somewhere in the bulk of the switch and away from the ohmic contacts. We mainly analyse the time-dependent characteristic of the mode, the theoretical analysis results are in excellent agreement with the experiment.     

用于脉冲中子探测器的小型化高压模块性能研究

高压电源的性能特性对闪烁中子探测器的性能有着十分重要的影响。为克服传统高压供电设备体积大、便携性差的问题,在便携式脉冲中子探测器研制中拟采用内部集成小型化高压模块为光电倍增管提供高压的技术路线。根据实验结果,选用的高压模块最高输出高压可达2.5 kV并且具有良好的输出一致性,可适应16~36 V的工作电压,连续工作稳定性及温度稳定性优良,可以满足脉冲中子探测器研制的要求。     

Portable Wireless Intelligent Electrochemical Sensor for the Ultrasensitive Detection of Rutin Using Functionalized Black Phosphorene Nanocomposite

To build a portable and sensitive method for monitoring the concentration of the flavonoid rutin, a new electrochemical sensing procedure was established. By using nitrogen-doped carbonized polymer dots (N-CPDs) anchoring few-layer black phosphorene (N-CPDs@FLBP) 0D-2D heterostructure and gold nanoparticles (AuNPs) as the modifiers, a carbon ionic liquid electrode and a screen-printed electrode (SPE) were used as the substrate electrodes to construct a conventional electrochemical sensor and a portable wireless intelligent electrochemical sensor, respectively. The electrochemical behavior of rutin on the fabricated electrochemical sensors was explored in detail, with the analytical performances investigated. Due to the electroactive groups of rutin, and the specific π-π stacking and cation–π interaction between the nanocomposite with rutin, the electrochemical responses of rutin were greatly enhanced on the AuNPs/N-CPDs@FLBP-modified electrodes. Under the optimal conditions, ultra-sensitive detection of rutin could be realized on AuNPs/N-CPDs@FLBP/SPE with the detection range of 1.0 nmol L⁻¹ to 220.0 μmol L⁻¹ and the detection limit of 0.33 nmol L⁻¹ (S/N = 3). Finally, two kinds of sensors were applied to test the real samples with satisfactory results.