Verrucosidin Derivatives from the Deep Sea Cold-Seep-Derived Fungus Penicillium polonicum CS-252

Six novel verrucosidin derivatives, namely, poloncosidins A–F (1–6), together with one known analogue (7), were isolated and identified from the deep-sea-derived fungus Penicillium polonicum CS-252, which was obtained from cold-seep sediments collected in the South China Sea at a depth of 1183 m. Their structures were mainly established on the basis of a detailed interpretation of NMR spectroscopic and mass spectrometric data. The relative and absolute configurations of compounds 1–6 were determined by ECD calculations and a DP4+ probability analysis. Compounds 1–5 represent the first examples of verrucosidins with a 2,5-dihydrofuran ring which is uncommon among the known analogues. These compounds exhibited inhibitory activities against several human and aquatic pathogens with MIC values ranging from 4 to 32 μg/mL.     

一种针对压缩域信号的新型锁相环技术

针对通信信号压缩采样获得的压缩域信号频率、相位提取问题,提出了一种基于压缩感知的新型锁相环技术。通过深入研究压缩域的信号估计问题,提出了压缩域锁相环路,可以直接在压缩域同步跟踪信号频率和相位变化,不再需要高复杂度的信号重构处理。分析了环路模型及其估计性能,并针对该锁相环可行性和性能分别进行了仿真实验。仿真结果不仅验证了压缩域锁相环的可行性,同时表明该环路能够实现高动态信号的高精度频率提取。压缩域锁相环的应用潜力较大,例如可以作为压缩感知通信接收机的同步解调方法。     

Theoretical Study on Wavelength Conversion Based on Cross Phase Modulation Using Semiconductor Optical Amplifiers

Performances of wavelength converted signal by cross phase modulation (XPM) using semiconductor optical amplifiers (SOA's) were studied by the use of the multi-section model. Results show that they are related to both the phase arm bias current of the XPM wavelength converter and its operation. When the conversion is under the in-phase operation, the peak extinction ratio (ER) and the chirp frequency of the converted signal increase according to the decrease of the phase arm bias current, but the input signal power dynamic range decreases. When the converter is under the out-of-phase operation, the chirp frequency decreases with the decrease of the phase arm bias current, while the peak ER and the input power dynamic range keep almost the same when the phase arm bias current changes.     

热蒸发紫外LaF3薄膜光学常数的表征

薄膜光学常数的精确测定对于设计和制备多层薄膜具有重要意义。在JGS1型熔融石英基底上,采用热蒸发沉积方法制备了不同厚度的LaF3单层薄膜样品,利用光度法来获取弱吸收薄膜和基底的光学常数,计算得到其在185～450nm范围内折射率n和消光系数k的色散曲线。实验结果表明,当膜层厚度较薄时,LaF3薄膜折射率表现出不均匀性现象。随着薄膜厚度的增加,薄膜折射率不均匀性减小。在求解过程中选用不均匀模型后,拟合结果与实际测试光谱曲线吻合得很好,提高了薄膜光学常数的计算精度。     

Porous ZnAl2O4 spinel nanorods: High sensitivity humidity sensors

Porous zinc aluminate (ZnAl₂O₄) spinel nanorods were synthesized via a homogeneous co-precipitation approach followed by a heat treatment at 900 °C. The porous rod-like nanostructures not only increase the efficiency of adsorption sites, but also promote the dissociation of water adsorbed on nanorod boundaries and pore-walls. Moreover, they also provide an effective and fast channel for the transport of water vapor and liquid. Therefore, the impedance signal of the sensors based on the porous nanorods presents high sensitivity, good linearity, small hysteresis, and fast response/recovery time to humidity. Additionally, the sensors are also relatively stable to humidity for a long time. This study demonstrates that porous ZnAl₂O₄ nanorods are a promising platform for the construction of humidity sensors.     

乌头酸-丙烯酸共聚物的合成及性能研究

以柠檬酸为原料,经分子内脱水生成乌头酸,与少量丙烯酸合成了乌头酸一丙烯酸共聚物(AA—AA)。对共聚物的阻垢、分散、缓蚀及生物降解性能进行了测试,结果表明,AA—AA不仅有优良的阻垢分散性能,而且具有很好的生物降解性能,28d的生物降解率可达56．73％。     

磷酸反应槽拱门内衬碳砖温度应力的分析

运用有限元分析软件ANSYS对磷酸反应槽拱门墙体内衬碳砖在温度载荷下的应力进行模拟分析,结果表明:拱门碳砖局部较大的拉应力成为拱门碳砖墙体产生破坏的主要因素.选择膨胀量比混凝土大的碳砖内衬拱门,虽然碳砖层仍受拉应力的影响,但应力值大幅下降,可以解决拱门墙体内衬碳砖在工作温度下产生破坏的问题.     

粒子加速器筒体开方孔有限元分析

某粒子加速器筒体上开一方形孔,与方形法兰锻件焊接.常规设计方法没有对容器重要区域的应力进行严格而详细的应力分析计算,从而也就无法对由不同载荷引起的、对容器失效有不同影响的应力加以不同的限制.运用有限元分析软件ANSYS对某粒子加速器开方孔的应力进行模拟分析,采用JB 4732-1995对简体与方形锻件法兰焊接部分进行强度校核,结果表明,强度满足要求.     

影响Claus尾气加氢催化剂性能的动力学研究

实验室通过对低温Claus尾气加氢催化剂动力学研究,考察了Claus尾气含硫化合物加氢反应的规律。通过对影响Claus尾气加氢催化剂性能的主要因素分析,阐述了过程气中烃类反应导致的催化剂积炭速率与烃含量、催化剂使用温度、催化剂运转时间的关系;通过使用XRD、SEM等技术手段,对热老化前后Claus尾气加氢催化剂晶相、金属分散、孔结构等性质进行测试和表征。从不同角度研究、探讨影响催化剂性能的因素,对于低温Claus尾气加氢催化剂及其配套工艺的开发和应用具有指导意义。     

A two-step route to synthesize highly oriented ZnO nanotube arrays

Large-scale and highly oriented ZnO nanotube arrays are synthesized on transparent conductive glass substrates by a two-step route. First, ZnO nanorod arrays were prepared by electrochemical deposition from an aqueous solution of zinc nitrate. Then, hollow ZnO nanotubes were obtained by the selective dissolution of the electrodeposited ZnO nanorods in potassium hydroxide solution. Field emission scanning electron microscopy (FESEM) and X-ray powder diffraction (XRD) have been used to characterize the morphology and structure of the derived products. The effect of the concentration of alkali, dissolution time, and temperature on the formation process and morphologies of ZnO nanotube arrays has been discussed.