纳米尺寸氧化钇团簇阴离子与正丁烷反应的研究

在单一原子量分辨水平上研究纳米尺寸过渡金属氧化物团簇(M_xO_y^q)与小分子的反应不仅能够获得氧化物纳米颗粒的反应性随原子组成和尺寸连续变化的演变规律, 而且对认识其结构特征以及表面活性氧物种(如O^-•自由基)的产生机制等具有重要意义. 本工作分别采用耦合快速流动反应管和耦合四极质量过滤器-线形离子阱的两套反射式飞行时间质谱研究了不同“氧缺陷指数”(Δ)的氧化钇团簇Y_xO_y^- (x≤50,y≤76; Δ≡2y–1–3x, Δ=0~5)和掺杂氟(F)原子团簇Y _xO_yF^- [x≤49,y≤74; Δ≡(2y+1)–1–3x, Δ=1]与 n-C₄H₁₀分子的反应. 实验观测到Δ=1系列团簇(Y₂O₃)_NO^- (N=1~25)、(Y₂O₃)_NYO₂F^- (N=1~24)及Δ=4系列团簇(Y₂O₃)_NYO₄^- (N=1, 3~24)具有氢抽取反应活性, N≥2时其它Δ系列团簇(Δ=0, 2, 3, 5)在相同实验条件下没有表现出明显的反应性. 密度泛函理论研究Δ=1或4系列小尺寸团簇(Y₂O₃)_NY_xO_yF_0,1^- (N≤4;x=0, 1)的结构揭示O^-•自由基是氢抽取反应的活性位点, 结合实验可推测Δ=1或4系列纳米尺寸团簇(Y₂O₃)_NY_xO_yF_0,1^- (x=0, 1)结构中也含有O^-•自由基. 这些结果表明Δ=0系列惰性纳米尺寸团簇(Y₂O₃)_NYO₂^-可以通过吸附一个O₂分子发生电子转移生成O^-•自由基(O^2-+O₂→O^-•+O₂^-•), 也可以通过掺入F原子的方式生成O^-•自由基(O^2-+F^•→O^-•+F^-).     

A Rare 2D Framework Cu(atz)2 with Ferrimagnetic and High Proton Conductivity

Materials combining proton conductivity and magnetism have attracted great attention in recent years due to their intriguing application in sensors and fuel cells. Herein a two-dimensional metal-organic framework, [Cu(atz)₂(H₂O)₂]⋅H₂O ( 1 ) (Hatz=5-aminotetrazole), has been obtained in a green synthesis method. The single-crystal structure revealed that the atz⁻ ligands as linkers coordinate with copper ions to sql networks, between which water molecules are immobilized through hydrogen bonds. The resulting complex 1 exhibits a high proton conductivity of 1.11×10⁻⁴ and 6.19×10⁻⁴ S cm⁻¹ at room temperature and 333 K, respectively, under 98% RH with an activation energy of 0.56 eV. Upon dehydration, the proton conductivity of 1_dg drops by an order of magnitude. Furthermore, the magnetic behavior changes from long-range ferrimagnetic ordering of 1 to canted antiferromagnetic behaviour of 1_dg .     

Deglycosylated Azithromycin Attenuates Bleomycin-Induced Pulmonary Fibrosis via the TGF-β1 Signaling Pathway

Idiopathic pulmonary fibrosis (IPF) is a progressive, life-threatening lung disease characterized by the proliferation of myofibroblasts and deposition of extracellular matrix that results in irreversible distortion of the lung structure and the formation of focal fibrosis. The molecular mechanism of IPF is not fully understood, and there is no satisfactory treatment. However, most studies suggest that abnormal activation of transforming growth factor-β1 (TGF-β1) can promote fibroblast activation and epithelial to mesenchymal transition (EMT) to induce pulmonary fibrosis. Deglycosylated azithromycin (Deg-AZM) is a compound we previously obtained by removing glycosyls from azithromycin; it was demonstrated to exert little or no antibacterial effects. Here, we discovered a new function of Deg-AZM in pulmonary fibrosis. In vivo experiments showed that Deg-AZM could significantly reduce bleomycin-induced pulmonary fibrosis and restore respiratory function. Further study revealed the anti-inflammatory and antioxidant effects of Deg-AZM in vivo. In vitro experiments showed that Deg-AZM inhibited TGF-β1 signaling, weakened the activation and differentiation of lung fibroblasts, and inhibited TGF-β1-induced EMT in alveolar epithelial cells. In conclusion, our findings show that Deg-AZM exerts antifibrotic effects by inhibiting TGF-β1-induced myofibroblast activation and EMT.     

对称及非对称卟啉锌轴配反应的光谱及热力学研究

合成非对称对位取代5-(4-乙酰胺基苯基)-10，15，20-三(4-甲基苯基)卟啉锌。考察了Zn(p-X)TPP(X=Cl,H,CH₃，OCH₃)及非对称Zn(p-NHCOCH₃)(p-CH₃)₃TPP与咪唑类配体［Im、2-MeIm、N-MeIm、GMZ、NiIm(p-Cl)］轴配反应的电子吸收光谱。阐述了诸因素对谱带红移和A相似文献   

一种新的五日生物需氧量分析方法

利用荧光氧传感器连续监测封装在密闭培养皿中的废水溶氧浓度，提出了一种新的ＢＯＤ５分析方法，建立了两套ＢＯＤ５检测装置。实验结果表明，利用荧光氧传感器检测ＢＯＤ５，提高了测量的准确性和精度，可望成为新的标准化检测方法。     

Geometry and analysis of spin equations

We introduce W‐spin structures on a Riemann surface Σ and give a precise definition to the corresponding W‐spin equations for any quasi‐homogeneous polynomial W. Then we construct examples of nonzero solutions of spin equations in the presence of Ramond marked points. The main result of the paper is a compactness theorem for the moduli space of the solutions of W‐spin equations when W = W(x₁, …, x_t) is a nondegenerate, quasi‐homogeneous polynomial with fractional degrees (or weights) q_i < ½ for all i. In particular, the compactness theorem holds for the superpotentials E₆, E₇, E₈ or A_{n ? 1}, D_{n + 1} for n ≥ 3. © 2008 Wiley Periodicals, Inc.     

AR-Ag(I)体系的共振散射光谱法测定痕量银

在pH=4.4的NaAc-HAc缓冲介质和2.0×10-3mol/L十二烷基苯磺酸钠(SDBS)溶液中,Ag(I)与茜素红(AR)可形成较稳定的离子缔合物微粒,其在324、360和500nm处分别产生3个较强的共振散射峰。在最佳实验条件下,浓度在0.022～2.160μg/mL之间的Ag(I)与共振散射强度ΔI324nm呈较好的线性关系,检测限为0.139ng/mL。据此,建立了一种测定痕量银的共振散射新方法,并将该方法用于废胶片中痕量银的测定。     

Zero-voltage and zero-current-switching PWM hybrid full-bridge three-level converter

This paper proposes a zero-voltage and zero-current-switching pulsewidth modulation hybrid full-bridge three-level (ZVZCS PWM H-FB TL) converter, which has a TL leg and a two-level leg. The voltage stress of the switches of the TL leg is half of the input voltage, and the switches can realize ZVS, so MOSFETs can be adopted; the voltage stress of the switches of the two-level leg is the input voltage, and the switches can realize ZCS, so IGBT can be adopted. The secondary rectified voltage is a TL waveform having lower high-frequency content compared with that of the traditional FB converters, which leads to the reduction of the output filter inductance. The input current of the converter has quite little ripple, so the input filter can also be significantly reduced. The operation principle of the proposed converter is analyzed and verified by the experimental results. Several ZVZCS PWM H-FB TL converters are also proposed in this paper.     

Synthesis and photoluminescence properties of ZnO nanowire arrays

In this paper we report a chemical method named coordination reaction method to synthesize ZnO nanowire arreys. ZnO nanowires with the diameter about 80nm were successfully fabricated in the channels of the porous anodic alumina (PAA) template by the above coordination reaction method. The microstructures of ZnO/PAA assembly were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X‐ray diffraction (XRD). The results showed that the ZnO nanowires can be uniformly assembled into the nanochannels of PAA template. The growth mechanism of ZnO nanowires and the conditions of the coordination reaction are discussed. Photoluminescence (PL) measurement shows that the ZnO/PAA assembly system has a blue emission band caused by the various defects of ZnO. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)