Single layer graphitic carbon nitride-modified graphene composite as a fiber coating for solid-phase microextraction of polycyclic aromatic hydrocarbons

The authors describe a three-dimensional single layer graphitic carbon nitride-modified graphene composite (g-C₃N₄@G) deposited on a stainless steel wire by a sol-gel technique. The coated fiber was applied to direct immersion solid-phase microextraction of trace levels of polycyclic aromatic hydrocarbons (PAHs) from cosmetics samples prior to their determination by gas chromatography with mass spectrometry (GC-MS). Due to π stacking interaction and hydrophobic interaction between the g-C₃N₄@G coating and the analytes (naphthalene, acenaphthene, fluorene, phenanthrene, fluoranthene and pyrene), the fiber displays an excellent adsorption capability for the analytes. Under optimized conditions, the method has a wide linear range, low LODs (from 1.0 to 2.0 ng L⁻¹), good repeatability and high recoveries. It was successfully applied to the determination of PAHs in cosmetics. The g-C₃N₄@G fiber also exhibited good durability.

Schematic of a three-dimensional single layer graphitic carbon nitride-modified graphene composite (g-C₃N₄@G) that was coated onto a stainless steel wire for the direct-immersion solid phase microextraction of trace levels of polycyclic aromatic hydrocarbons prior to gas chromatography-mass spectrometric detection.

     

Synthesis and biological evaluation of oxoapratoxin E and its C30 epimer

30R- and 30S-oxazoline analogues of apratoxin E have been prepared with late-stage formation of an oxazoline ring. These two compounds have a potent inhibitory effect on HCT-116 cell proliferation with IC₅₀ values of 345 and 638 nM, respectively. These results suggest that apratoxin E oxazoline bioisosteres are approximately 6-fold less potent than their thiazoline parent compounds. A positive impact of the 30R conformation on antiproliferative activity was also observed, with approximately 2-fold enhancement when compared to the 30S epimer.     

Formation of abnormal dual‐peak profiles in large tilt angle boron implantation

Large tilt angle (LTA) implantation has been employed in Si manufacturing processes in many applications, such as lightly doped drain and halo implant. The depth profile of boron ions usually consists of only single peak at incident angle of 0° with respect to the perpendicular of the silicon surface. However, an abnormal dual‐peak profile was observed at LTA (>40°) with incident energy of 160 keV. By using a Monte Carlo method to simulate the ion implant process, it was found that the projected range of boron ions agrees completely with the formation of the first peak position that is shallower in depth, while the cause for the second peak that corresponds with a depth much deeper in the Si substrate was unknown. During the simulation, it was also found that when the tilt angle was increased, the sputtering yields and Si displacements increased significantly, and this phenomenon indicates that during LTA implantation, Si damage may not be negligible anymore. The Si damage effect that was as due to either low Si density or transient Si displacement in the simulation could have led to partial incident boron ions penetrating much deeper into the Si substrate and thus, caused the emergence of the second peak. Copyright © 2016 John Wiley & Sons, Ltd.     

不同等级煤与油共炼的转化率差异及残渣分析

选取安徽褐煤、辽宁褐煤和贵州烟煤三种煤为原料,以油溶性环烷酸钼为催化剂,分别与马瑞常渣(MRAR)、克炼常渣(KAR)以及催化裂化油浆(FCCS)在高压釜内模拟悬浮床加氢共炼反应。结果表明,不同的油体系下,两种褐煤都能达到83%以上的转化率,而对于贵州烟煤,转化率最高的FCCS体系与最低的KAR体系分别为67.75%和50.31%,相差很大。采用FT-IR和SEM分析反应后固体残渣,计算了固体残渣中脂肪族和芳香族中各个基团的相对含量,并对比了不同体系反应后固体残渣的微观形貌。结果表明,KAR体系的固体残渣脂肪链较长,支链化程度高,取代度较低。转化率较高的褐煤反应后固体残渣结构松散,分散度高;转化率较低的烟煤固体残渣随着转化率降低,残渣颗粒逐渐变大,表面更加光滑,板结程度加深。     

Double telecom band thermo-optic switch based on dual-line filled photonic liquid crystal fibres

We demonstrate a thermo-optic switch based on photonic liquid crystal fibres (PLCFs) in which two lines of air hole are selective filled with liquid crystal (LC), with a high extinction ratio of more than 20 dB around 1310 nm and 1550 nm. Only in the range of 2.0°C it can perform a turn off and on operation of transmitted light in the second telecom band around 1550 nm while the first telecom bands around 1310 nm is still on. Due to the splitting of the bandgap, the switching function is achieved in this kind of PLCFs. Before the cleaning point (CP) of LC, a broad bandgap from about 1120 nm to 1320 nm splits into two ones, which are continuing inducing huge bandgap extension to shorter wavelength and longer wavelength after the CP of LC, respectively. Moreover, the temperature responses around the CP of LC is also investigated. Its sensitivity is about ?92.32 nm/°C around the CP of LC. Therefore, such kind of selective-filled PLCFs could find potential applications as thermo-optic switch and temperature sensor in the telecom band.     

斜冲击界面动力学研究

讨论了界面受到斜冲击时的动力学问题。有效冲击摩擦系数被处理成冲击过程及初始冲击角的函数 ;界面的法向响应描述计及弹性接触、弹性变形极限以及依赖于应变、应变率及温度的完全塑性接触 ;界面在冲击过程中的构形变化也予考虑 ,并采用平均应变、应变率及最大温升的概念与估算。这种新的斜冲击界面动力学模型用于数值模拟刚性球对于延性靶的斜冲击实验 ,计算与实验比较 ,结果是令人满意的。     

Polyacrylamide hydrogels with phenylboronic acid moieties for the imprinting of proteins

<正>In this letter,N-acryloyl-3-aminophenylboronic acid(AAPBA) was synthesized and then examined as a new functional monomer for protein imprinting.It was allowed to be copolymerized with acrylamide to produce hemoglobin- or lysozyme-imprinted hydrogels.In template rebinding tests,the imprinted gels showed significant increase in the specific binding with the increase of the AAPBA amounts in the prepolymerization recipes.These results indicate that AAPBA may be a useful functional monomer for its moderate interactions with protein molecules.     

Strontium chloride-catalyzed one-pot synthesis of 4(3H)- quinazolinones under solvent-free conditions

<正>Strontium chloride was used as an efficient and recyclable catalyst in one-pot condensation of anthranilic acid,ortho esters and amines leading to the formation of 4(3H)-quinazolinone derivatives in good yields at room temperature under solvent-free conditions.     

A new dicaffeoyl quinic acid from Nannoglottis ravida

<正>A new dicaffeoyl quinic acid,nannoglottisin A,has been isolated from an endemic plant of Nannoglottis ravida,and the structure of the compound was identified by means of spectroscopic analysis.     

The stable planar conformation of the γ-butyrolactone ring in solution

<正>The conformations ofγ-butyrolactone ring in solution were deduced on the basis of ~1H NMR spectra of geminal protons of the butyrolactone ring.A series of optically pure(Z)-(-)-4-(1'-alkoxyl-1'-carbalkoxy-methylene)-5(R)[(1R)-menthyloxy]-γ-butyr-olactones with a stable planar conformation of γ-butyrolactone ring were found.