新型α-蒎烯基苯磺酰胺类化合物的合成及其抗真菌活性

以天然产物α蒎烯为原料,经多步反应合成了9个新型α-蒎烯基苯磺酰胺类化合物（7a~7i）,其结构经¹H NMR、 ¹³C NMR、 FT-IR和MS(ESI)表征。采用离体法测试了化合物的抗真菌活性。结果表明：在50 μg·mL^-1浓度下,目标化合物对黄瓜枯萎病菌、花生褐斑病菌、苹果轮纹病菌、小麦赤霉病菌以及番茄早疫病菌等5种植物病原菌有一定的抑制活性,其中化合物α-蒎烯基p-氯苯基磺酰胺(7d, R=p-Cl)和α-蒎烯基o-硝基苯基磺酰胺(7h, R=o-NO₂)对苹果轮纹病菌的抑制率分别为83.9%和79.6%（B级活性水平）,优于阳性对照百菌清（75.0%）;化合物α-蒎烯基m-甲基苯基磺酰胺(7b, R=m-Me)对番茄早疫病菌的抑制率为82.2%（B级活性水平）,优于阳性对照百菌清（73.9%）。-     

Reaction Mechanism of H2-Assisted C3H6-SCR over Ag-CexZr Catalyst as Investigated by In situ FTIR

A series of silver-doped cerium zirconium oxide(Ag-Ce_xZr) samples was synthesized successfully for selective catalytic reduction of nitric oxide(NO) with hydrogen and propene(H₂/C₃H₆-SCR) under excess oxygen condition. The catalytic activity test proved that Ag-Ce_0.4Zr exhibited the best C₃H₆-SCR activity. Hydrogen(H₂) significantly enhanced NO conversion and widened the temperature window. Multi-technology characterizations were conducted to ascertain the properties of fabricated catalysts including X-ray diffraction(XRD), Fourier transform infrared spectrometry(FTIR), scanning electron microscopy(SEM) and H₂ temperature programmed reduction (H₂-TPR). In situ FTIR results demonstrated that various types of nitrates and chelating nitrite were generated on Ag-Ce_xZr after introduction of NO. Besides, adding H₂ could increase the concentration of bidentate nitrate and chelated bidentate nitrate dramatically, especially for Ag-Ce_0.4Zr catalyst. Transient reaction between pre-adsorbing NO and C₃H₆/C₃H₆+H₂ illuminated that the most active intermediate was chelating nitrite,which was promoted significantly by H₂ participation. Furthermore, adding H₂ improved the formation of organo-nitro(R-NO₂), which was the key intermediate in C₃H₆-SCR. The reaction mechanism over Ag-Ce_xZr catalysts was proposed at 200℃ as follows:nitric oxide(NO)+propene(C₃H₆)+hydrogen(H₂)+oxygen(O₂)→chelating nitrite(NO₂^-)+acrylate-type species(C_xH_yO_z)→organo-nitro(R-NO₂)→isocyanate(-NCO)+cyanide(-CN)→nitrogen(N₂).     

Fluorescence Signal Amplification Strategies Based on DNA Nanotechnology for miRNA Detection

In this review,the most recent progresses in the field of fluorescence signal amplification strategies based on DNA nanotechnology for miRNA are summarized.The types of signal amplification are given and the principles of amplification strategies are explained,including rolling circle amplification(RCA),catalytic hairpin assembly(CHA),hybridization chain reaction(HCR)and DNA walker.Subsequently,the application of these signal amplification methods in biosensing and bioimaging are covered and described.Finally,the challenges and the outlook of fluorescence signal amplification methods for miRNA detection are briefly commented.     

Two-dimensional Molecular Phase Transition of Alkylated-TDPB on Au(111) and Cu(111) Surfaces

The derivatives of aromatic cores bearing alkyl chains with different lengths are of potential interest in on-surface chemistry, and thus have been widely investigated both at liquid-solid interfaces and in vacuum. Here, we report on the structural evaluation of self-assembled 1,3,5-tri(4-dodecylphenyl)benzene(TDPB) molecules with increased molecular coverages on both Au(111) and Cu(111) surfaces. As observed on Au(111), rhombic and herringbone structures emerge successively depending on surface coverage. In the case of Cu(111), the same process of phase conversion is also observed, but with two distinct structures. In comparison, the self-assembled structures on Au(111) surface are packed more densely than that on Cu(111) surface under the same preparation conditions. This may fundamentally result from the higher adsorption energy of TDPB molecules on Cu(111), restricting their adjustment to optimize a thermodynamically favorable molecular packing.     

边学边干,教研结合——谈"操作系统"课程教学改革

计算机应用的飞速发展对高等院校计算机专业课程的教学提出了更高的要求。操作系统作为计算机科学与技术的核心专业课程,在计算机专业人才培养中具有极其重要的地位。本文针对新形势下研究型大学创新性人才培养的要求,探讨了网络时代多元化教学手段在计算机操作系统课程教学改革中的实践;提出了在课程教学中走“边学边干”的教学路线,开展多方位的网络化教学,同时坚持教研结合,培养学生的研究创新能力。     

MATLAB曲面绘制中的挖补方法

在MATLAB绘图中,将函数数据的某一部分换成内置变量NaN(或Inf),或者将函数数据中的NaN换成适当的实数,可分别实现绘图中的挖、补方法.并且给出一些具体的应用实例.     

高静水压诱导水稻产生突变的研究

 以78 MPa高静水压力处理已浸泡10 h的水稻（Oryza sativa L.）粤香占、粤丰占和测64种子12 h,成苗后移栽至大田,对其处理当代和后代的农艺性状进行调查和分析,结果表明,处理当代中,粤香占、粤丰占和测64的穗粒数分别增加了5.2%、1.2%和17.0%,且测64达到显著性差异水平;测64处理的生育期延长10 d,而粤香占和粤丰占则分别早熟5 d和2 d 。在处理的当代和后代中出现了可遗传的突变体,突变性状中既有质量性状也有数量性状,其中紫色叶鞘和穗下节伸长属于质量性状突变,株高、粒长和穗粒数等属于数量性状突变。突变频率因品种不同而存在差异,表现为：测64>粤丰占>粤香占。通过4年6代的筛选,共获得近100份包括叶、茎、穗、粒、育性和生育期等性状发生明显变异的突变体,已稳定的突变株系22个,其中7个突变株系的综合性状明显较对照好,具有良好的应用前景。     

溴化二水二(皮考林酰胺)合钴配合物的合成及晶体结构

用皮考林酰胺、六水合硝酸钴和苄基溴反应制得一种新配合物[(C6H6N2O)2Co(H2O)2].B r2,通过红外光谱、元素分析及X射线晶体衍射对化合物进行了表征.结构分析结果表明,配合物属单斜晶系,P2(1)/n空间群,晶胞参数为:a=0.647 61(5)nm,b=1.026 43(9)nm,c=1.264 14(11)nm,β=93.823 0(10),°V=0.838 44(12)nm3,Z=4,Dc=1.977 g/cm3,μ=5.812 mm-1,F(000)=490,R1=0.071 0,wR2=0.251 6.配合物中,Co(Ⅱ)离子为六配位的八面体构型;相邻单元间通过N—H…B r和O—H…B r氢键相互连结而形成三维网状结构.     

2-十二烷基二硫代-4-苯基-1,3,4-噻二唑-5-硫酮的合成及其对铜的缓蚀性能

合成了2-十二烷基二硫代-4-苯基-1,3,4-噻二唑-5-硫酮(DPTT),用元素分析、IR1、H NMR等技术对化合物进行了结构表征.采用动态旋转挂片法考察了DPTT和苯并三唑(BTA)复配时对铜的缓蚀作用.结果表明,单一DPTT在浓度为3.0 mg/L时缓蚀效果最佳;DPTT与BTA复配使用时显示出较好的协同效应,1.0 mg/L DPTT和1.0 mg/L BTA复配时缓蚀效果最好.     

非傍轴矢量高斯光束

对傍轴近似下的光束传输变换问题进行了广泛的研究.但是,当光束有大的发散角或与波长相比拟的小光斑尺寸时,傍轴近似不再成立.已发展了多种非傍轴方法用以研究非傍轴光束的传输问题.对非傍轴光束的研究方法作了总结,使用角谱表示法和瑞利衍射积分公式对非傍轴矢量高斯光束的传输作了分析和比较.结果表明,基于瑞利衍射积分公式推导出的非傍轴矢量高斯光束在自由空间传输的解析公式在传输距离远大于波长时是严格的解析结果,并且在有光阑的情况下也是适用的.光束的非傍轴性主要由f参数决定,但当有光阑存在时,截断参数也对光束非傍轴行为产生影响.