Hyperchaos,quasi-period and coexisting behaviors in second-order-memristor-based jerk circuit

The European Physical Journal Special Topics - This paper generalizes a second-order-memristor-based jerk circuit, which is achieved by substituting the first-order memristor contained diode-bridge...     

超滤、高效液相色谱和毛细管电泳的多维组合用于胎脑垂体组织培养液的分离分析

采用超滤、高效液相色谱和毛细管电泳的多维组合分离分析了胎脑垂体组织培养液的成分，比较了各种工具的不同组合产生的分离效果，考察了获取最多信息量或达到最佳分离的条件，获得了满意结果。     

密度泛函理论下的分子总体电负性与调和平均电负性的关系

根据密度泛函理论定义的有效原子电负性，讨论了分子中总体电负性与调和平均电负性之间的关系，得到了调和平均电负性非常接近于总体电负性的结论，同时，说明了两者相似的原因，并对一系列分子给出了它们的数值比较．     

用毛细管电泳-激光诱导荧光-增强型电荷耦合检测器测定痕量氨基酸

本文对用毛细管电泳－激光诱导荧光－增强型电荷耦合检测器测定氨基酸衍生物进行了研究。考察了荧光黄异疏氰酸酯衍生氨基酸的各种条件。在优化条件下，10－8～10－6mol／L浓度范围内精氨酸与其衍生物的荧光强度呈良好的线性关系，最小可衍生化的精氨酸浓度为5×10－10mol／L。     

气相色谱/质谱分析烟草中的主要生物碱

用毛细管气相色谱法测定烟草中烟碱、降烟碱、麦斯明、二烯烟碱、新烟碱、去氢新烟碱、2,3′-联二吡啶、可替宁8种主要生物碱的方法。烟草样品经二氯甲烷/甲醇(V/V,3∶1)萃取,过一次性滤膜,进样,经DB-5MS毛细管柱分离,由气相色谱-氢火焰离子化检测器(FID)检测定量,质谱定性。该方法操作简单,重现性好,回收率较高。8种生物碱相对标准偏差为2.59%~7.07%;回收率为89.4%~98.7%。     

Synthesis, crystal structure and configuration of acetylated aryl Pyrogallol[4]arenes

A series of aryl and ferrocenyl pyrogallol[4]arenes have been synthesized by the HCl-catalyzed condensation reactions of pyrogallol with aromatic aldehydes and ferrocenecarbaldehyde. The fully acetyl and ethoxycarbonylmethoxy derivatives were also prepared and fully characterized. The crystal structures show that acylated phenyl pyrogallol[4]arene exists in rctt (cis-trans-trans) configuration, while the corresponding ferrocenyl pyrogallol[4]arene in rccc (all cis) configuration.     

FCC硫转移剂MgAlCuFe复合氧化物的结构与性能:金属盐前体的影响

分别以硝酸盐、盐酸盐和硫酸盐为金属盐前体,采用共沉淀法合成了MgAlCuFe类水滑石前驱体,经过700℃焙烧6h后,制得三种新型FCC硫转移剂.运用X射线衍射、热重、氮气吸附和红外光谱对这三种硫转移剂的结构和性能进行了表征,并采用改装的WRP-3热重天平评价了其氧化吸硫和还原脱硫的性能.结果表明,三种金属盐均可得到结构规整的类水滑石前驱体,经过焙烧后得到复合氧化物MgAlCuFe.与采用盐酸盐和硫酸盐作前体相比,由硝酸盐制得的硫转移剂具有较大的比表面积,其饱和吸附硫容和氧化吸硫速率均较高,6min可达到1.54g/g的饱和吸附能力,同时具有较强的还原脱硫能力.     

Analysis of chloroacetanilide herbicides in water samples by solid-phase microextraction coupled with gas chromatography-mass spectrometry

A solid-phase microextraction (SPME) method has been developed for the determination of 3 chloroacetanilide herbicides in both fresh and seawater samples. The extracted sample was analyzed by gas chromatography with mass spectrometry detection (GC-MS), and parameters affecting SPME operation including fibre type, sample pH, sample temperature, mixing speed and extraction time have been evaluated and optimized. The amount of dissolved organic matter (DOM) and the salt content both affected SPME extraction efficiency, but the presence of other competitive extractants such as organochlorine pesticides (OCPs) in the matrix showed no insignificance interference. The limit of detection (LOD) for acetochlor, metolachlor and butachlor were 1.2, 1.6 and 2.7 ng L⁻¹, respectively. The recoveries for the herbicides ranged from 79 to 102%, and the linear dynamic range was from 10 to 1000 ng L⁻¹. The developed method has been used to monitor herbicides contaminations in coastal water samples collected around Laizhou bay and Jiaozhou bay in Shandong peninsula, China. The concentrations of acetochlor and metolachlor ranged from undetectable to 78.5 ng L⁻¹ and undetectable to 35.6 ng L⁻¹, respectively. Butachlor was not observed but in only one sample and the concentration is lower than the limit of quantification (LOQ). The concentrations of the three herbicides in this study are low compared to most of the other places reported.     

化学溶液分解法制备(Bi0.9Nd0.1)2Ti2O7薄膜

采用化学溶液分解法（CSD）在p—Si（111）衬底上制备了（Bi0.9Nd0.1）2Ti2o7薄膜。用X射线衍射技术分析了薄膜的结构和结晶性，结果显示，在600℃退火10min得到了结晶性较好、表面致密的多晶薄膜；用原子力显微镜描述了薄膜的表面形貌，与在XRD中观察到的择优取向是一致的；同时还研究了薄膜的电学性能。结果表明，在0～6V范围内，薄膜的漏电流小于1．53×10^10A；在室温100kHz下，其介电常数为166，介电损耗因子为0．227，显示出薄膜具有较好的绝缘性和介电性能。     

Syntheses of (-)-oleocanthal, a natural NSAID found in extra virgin olive oil, the (-)-deacetoxy-oleuropein aglycone, and related analogues

Phenolic compounds extracted from extra virgin olive oil have attracted considerable recent attention. One of the components, (-)-oleocanthal (1), an inhibitor of the COX-1 and COX-2 enzymes, possesses similar potency as the NSAID ibuprofen. In this, a full account, we disclose the first- and now second-generation syntheses of both enantiomers of the oleocanthals, as well as the first synthesis of the closely related (-)-deacetoxy-oleuropein aglycone and a series of related analogues for structure activity studies. To demonstrate the utility of the second-generation synthesis, multigram quantities of (-)-oleocanthal were prepared in 10 steps (14% overall yield) from commercially available D-lyxose.