Fabrication of tunable colloid crystals from amine-terminated polyamidoamine dendrimers

A pH-responsive colloidal crystal was assembled using core-shell composite spheres, poly(styrene-methyl methacrylate-acrylic acid) (P(St-MMA-AA)) spheres covered by generation 4 amine-terminated polyamidoamine dendrimers. The light reflection of the colloidal crystal film can be tuned at different pH due to different protonation level of the dendrimers. The method shows a facile way to fabricate diffraction-based chemical and biological sensors by exploiting the effect of photonic crystal cooperated with tunable nanoparticles.     

介孔炭负载铁基催化剂上醇与胺氧化偶合合成亚胺

亚胺是一类重要的含氮有机化合物,广泛应用于生物医药、精细化工和农业生产中.由于其分子中具有不饱和C=N双键,亚胺化合物可以通过不同化学过程(如氧化还原、加成、偶合等)合成多种衍生物.工业上合成亚胺普遍采用羰基化合物与胺偶合反应获得,由于该反应需要强酸作为催化剂和脱水剂,在应用中往往对设备造成不同程度的破坏.选择氧气或空气为氧化剂,通过醇与胺氧化偶合反应合成亚胺,其副产物只有水,是一条较为绿色的合成路线.近期研究表明,均相和负载型贵金属催化剂(如Pd,Pt和Au等)在该反应中表现出较好的低温催化性能,但需要在反应过程中添加大量碱性助剂.一些非贵金属氧化物催化剂如CeO2和MnOx/HAP等在该过程中表现出一定的催化活性,但其催化效率普遍较低,往往需要在24 h甚至更长反应时间实现～90％亚胺收率.因此仍需开发一些更为高效的非贵金属催化剂用于上述反应.本文以经过硝酸活化处理的有序多孔炭(CMK-3)为载体,制备了负载型氧化铁催化剂(FeOx/HCMK-3),考察了它在苯甲醇与苯胺氧化偶合合成亚胺反应中的催化性能,同时结合一系列表征手段研究了催化剂物理化学性质与其催化性能之间的关系.X射线衍射和氮吸附脱附结果显示,负载后的样品仍然保持了介孔炭原有的孔道结构,没有出现较大的氧化铁粒子;透射电镜、高角暗场扫描透射电镜及能量散射谱结果进一步显示,氧化铁物种相对均匀地分散在载体表面;程序升温还原结果显示,与块体氧化铁相比,FeOx/HCMK-3上的氧化铁物种(FeOx)更易被还原,这可能与氧化铁粒子较小有关.反应结果显示,在空气氛围中FeOx/HCMK-3能够高效催化醇与胺的氧化偶合反应,反应6h亚胺收率即达到98.8％.催化剂具有较高的稳定性,可多次循环使用,没有检测到铁物种流失.此外,FeOx/HCMK-3在多种苯甲醇衍生物与苯胺的氧化偶合反应中都表现出较好的催化性能.结合表征和反应结果可以推测,催化剂上的氧物种参与了反应过程,FeOx/HCMK-3催化剂具有较强的活化氧分子的能力,反应在该催化剂上可能遵循氧化-还原机理.该催化剂上醇与胺氧化偶合反应主要经历两个连续的反应过程:首先苯甲醇被FeOx/HCMK-3催化剂上的活泼氧物种氧化生成苯甲醛中间体;随后,在反应中生成的醛在催化剂上迅速与胺反应生成亚胺化合物,同时催化剂通过与空气中氧分子反应恢复到初始状态,完成整个催化循环.     

神经网络在捷联式寻北仪中的应用研究

介绍扫联式寻北仪的工作原理,研究当车体受到随机干扰时如何提高寻北仪的寻北精度问题,神经网络对非线性曲线具有较好的曲线拟合能力,用神经网络模拟寻北仪输出信号,用神经网络和低通滤波器相结合的组合滤波器对寻北仪输出数据进行处理,当系统受到冲击干扰时,用神经网络的输出代替实际传感器的输出,通过对实际的带有干扰的信号滤波结果表明,该组合滤波器能较好地抑制随机干扰对寻北结果的影响。     

Syntheses,characterization, and crystal structures of ruthenium(II)/(III) complexes with tridentate salicylaldiminato ligands

Treatment of [Ru(PPh₃)₃Cl₂] with one equivalent of tridentate Schiff base 2-[(2-dimethylamino-ethylimino)-methyl]-phenol (HL) in the presence of triethylamine afforded a ruthenium(III) complex [RuCl₃(κ²-N,N-NH₂CH₂CH₂NMe₂)(PPh₃)] as a result of decomposition of HL. Interaction of HL and one equivalent of [RuHCl(CO)(PPh₃)₃], [Ru(CO)₂Cl₂] or [Ru(tht)₄Cl₂] (tht = tetrahydrothiophene) under different conditions led to isolation of the corresponding ruthenium(II) complexes [RuCl(κ³-N,N,O-L)(CO)(PPh₃)] (2), [RuCl(κ³-N,N,O-L)(CO)₂] (3), and a ruthenium(III) complex [RuCl₂(κ³-N,N,O-L)(tht)] (4), respectively. Molecular structures of 1·CH₂Cl₂, 2·CH₂Cl₂, 3 and 4 have been determined by single-crystal X-ray diffraction.     

Effect of final heating temperature on crystallization of isotactic polypropylene nucleated with an aryl amide derivative as <Emphasis Type="Italic">β</Emphasis>-form nucleating agent

An aryl dicarboxylic acid amide compound TMB-5 is an efficientβ-form nucleating agent for isotactic polypropylene(iPP).Because of the solubility of TMB-5,superstructure and morphology of iPP crystals changed with melting conditions.Effects of final heating temperature(T_f)on heterogeneous nucleation of iPP/TMB-5 were investigated.It was discovered that the crystallization temperature increased with decreasing T_f value.The optical microscopic images indicated that when TMB-5 partially dissolved in iPP melt,the remaining(non-dissolved)TMB-5 facilitated the recrystallization of dissolved nucleating agent from the melt,which promoted crystallization.Complete solubility of nucleating agent caused the decreasing efficiency.TMB-5 recrystallized in the form of tiny needles,whose aggregates induced dendritic iPP crystals.     

Properties of poly(vinyl chloride)/wood flour/montmorillonite composites: Effects of coupling agents and layered silicate

Organomodified montmorillonite (OMMT) was prepared using cetylalkyl trimethyl amine bromide. OMMT and wood flour (WF) were surface-modified by silane coupling agent. They were melt-blended with polyvinyl chloride (PVC) and extruded into wood-plastic composite samples using one conical twin screw extruder. The effects of their contents on the composite mechanical properties were investigated. X-ray diffraction, transmission electron microscopy and scanning electron microscopy observed intercalation and dispersion of the OMMT. FTIR and X-ray photoelectron spectroscopy were used to analyze the silane-modification effects. The possible reaction mechanisms were proposed. After wood flour was modified by 1.5 phr silane, the impact strength and the tensile strength of wood flour-PVC composite were increased by 14.8% and 18.5%, respectively. Mechanical tests showed that the addition of OMMT did not enhance the untreated wood flour-PVC composites. However, adding 0.5% OMMT did improve the mechanical properties of the treated ones. The grafting improved the interfacial compatibility between components producing higher properties of the composites. Further addition of OMMT reinforced the composites. Too higher contents of silane and OMMT impaired some properties because of weak interfacial layer and higher concentrated stress. Cone calorimetry showed that the fire flame retardancy and smoke suppression of composites were strongly improved with the addition of OMMT.     

喹啉黄中各组分的定性及定量研究

利用高效液相色谱(HPLC)对喹啉黄各组分进行分离并定量,通过液相色谱–串联质谱(LC–MS/MS)对各组分进行定性。以0.01 mol/L乙酸铵溶液和甲醇为流动相进行梯度洗脱,利用Agilent XDB–C18色谱柱对喹啉黄各组分进行分离,峰面积归一化法定量。质谱采用电喷雾负离子(ESI–)模式电离,多反应监测(MRM)模式检测,对喹啉黄各组分进行定性。结果表明,喹啉黄主要成分为喹啉黄一钠盐和喹啉黄二钠盐,分别各有两种同分异构体,各组分质量浓度在5.0~100.0μg/m L范围内与峰面积呈良好的线性关系。加标回收率为98.2%~99.1%,测定结果的相对标准偏差为0.90%~1.58%(n=6)。该方法具有良好的精密度和准确度,可用于喹啉黄中各组分的测定。     

The Essence of Operators’ Weyl Ordering Scheme and New Operator Identities for Converting Q−P Ordering to Weyl Ordering

We find new operator formulas for converting Q?P and P?Q ordering to Weyl ordering, where Q and P are the coordinate and momentum operator. In this way we reveal the essence of operators’ Weyl ordering scheme, e.g., Weyl ordered operator polynomial ${_{:}^{:}}\;Q^{m}P^{n}\;{_{:}^{:}}$ , $$\begin{aligned} {_{:}^{:}}\;Q^{m}P^{n}\;{_{:}^{:}} =&\sum_{l=0}^{\min (m,n)} \biggl( \frac{-i\hbar }{2} \biggr) ^{l}l!\binom{m}{l}\binom{n}{l}Q^{m-l}P^{n-l} \\ =& \biggl( \frac{\hbar }{2} \biggr) ^{ ( m+n ) /2}i^{n}H_{m,n} \biggl( \frac{\sqrt{2}Q}{\sqrt{\hbar }},\frac{-i\sqrt{2}P}{\sqrt{\hbar }} \biggr) \bigg|_{Q_{\mathrm{before}}P} \end{aligned}$$ where ${}_{:}^{:}$ ${}_{:}^{:}$ denotes the Weyl ordering symbol, and H _m,n is the two-variable Hermite polynomial. This helps us to know the Weyl ordering more intuitively.     

循环级联式的多级PS光学互连网络

提出了一种可实现多级PS光学互连的循环系统,该循环系统主要是在现有的单级PS光学互连实验基础上,由LCD,CCD等光电子器件和计算机构成,这个循环系统可以实现多级PS光学互连和FPS光学互连。     

Validation study on 660 pesticide residues in animal tissues by gel permeation chromatography cleanup/gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry

A new method using gel permeation chromatography (GPC) cleanup followed by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS-MS) has been established for quantitative determination of 437 pesticide residues in animal tissues such as beef, mutton, pork, chicken, and rabbit. Based on an appraisal of the characteristics of both GC-MS and LC-MS-MS, validation experiments were conducted for 660 pesticides. In the method, 10 g animal samples were mixed with 20 g sodium sulfate and extracted with 35 mL of cyclohexane+ethyl acetate (1+1) twice by blender homogenization, centrifugation, and filtration. Evaporation was conducted and an equivalent of 5 g sample was injected into a 400 mm x 25 mm S-X3 GPC column, with cyclohexane+ethyl acetate (1+1) as the mobile phase at a flow rate of 5 mL/min. The 22-40 min fraction was collected for subsequent analysis. For the 368 pesticides determined by GC-MS, the portions collected from GPC were concentrated to 0.5 mL and exchanged with 5 mL hexane twice. For the 69 pesticides by LC-MS-MS, the portions collected from GPC were dissolved with acetonitrile+water (60+40) after taking the extract to dryness with nitrogen gas. In the linear range of each pesticide, the correlation coefficient was r > or = 0.98, exceptions being dinobuton, linuron, and fenamiphos sulfoxide. At the low, medium and high three fortification levels of 0.2-4800 microg/kg, recoveries fell within 40-120%, among which 417 pesticides recoveries between 60% and 120%, accounting for 95%, 20 analytes between 40% and 60%, accounting for 5%. The relative standard deviation was below 28% for all 437 pesticides. The limits of detection for the method were 0.2-600 microg/kg, depending on each pesticide.