新型功能碳材料的高压截获

高性能功能材料在诸多领域具有广泛的应用前景,是人们一直关注的研究热点。高压可以有效地改变物质的原子间距和成键方式,是获得新型功能材料的重要途径。在碳材料的高压研究中,许多有趣的功能碳材料,如光学透明碳、高强度弹性碳和超硬非晶碳等,已经通过不同的碳前驱体合成。本文简要介绍了作者近年来在低维碳基纳米复合材料高压研究中取得的进展,基于设计的不同低维碳前驱体,高压下截获了具有超硬特性、新型压致共价聚合及发光增强的碳材料。     

Optimal design of gears contact interface modification for an objective as minimum impact resistance of initial meshing-in time domain

Meccanica - In gear pair actual alternating meshing process, the comprehensive errors of the transmission system and the thermal elastic deformation of the teeth body cause the gears in the meshing...     

Synthesis and Characterization of Poly(ether ether ketone)s with (2,5‐dihydroxy)phenyl Side Group

A new monomer, (2,5‐dimethoxy)phenylhydroquinone (DMPH), was prepared in a two‐step synthetic procedure. One aromatic poly(ether ether ketone)s with 2,5‐dimethoxy phenyl side group (DMP‐PEEK) was synthesized via an aromatic nucleophilic substitution reaction with 4,4′‐difluorobenzophenone (DFB). Poly(ether ether ketone)s with 2,5‐dihydroxy phenyl side group (DHP‐PEEK) was obtained via hydrolysis of methoxy group on the DMP‐PEEK. Both of the high molecular weight polymers could be obtained despite the steric effect of the bulky pendant groups. The two polymers have good solubility at room temperature.     

Determination of nifedipine in dog plasma by high‐performance liquid chromatography with tandem mass spectrometric detection

Nifedipine is a dihydropyridine calcium channel blocker used widely in the management of hypertension and other cardiovascular disorders. In this work, a simple, rapid and sensitive liquid chromatography/tandem mass spectrometry method was developed and validated to determine nifedipine in dog plasma using nimodipine as the internal standard. Chromatographic separation was carried out on a C₈ column. The mobile phase consisted of a mixture of acetonitrile, water and formic acid (60:40:0.2, v/v/v) at a flow rate of 0.5 mL/min. Detection was performed on a triple quadrupole tandem mass spectrometer in selected reaction monitoring mode via an atmospheric pressure chemical ionization source. The method has a lower limit of quantification of 0.20 ng/mL with consumption of plasma as low as 0.05 mL. The linear calibration curves were obtained in the concentration range of 0.20–50.0 ng/mL (r = 0.9948). The recoveries of the liquid extraction method were 74.5–84.1%. Intra‐day and inter‐day precisions were 4.1–8.8 and 6.7–7.4%, respectively. The quantification was not interfered with by other plasma components and the method was applied to determine nifedipine in plasma after a single oral administration of two controlled‐release nifedipine tablets to beagle dogs. Copyright © 2013 John Wiley & Sons, Ltd.     

微型质子交换膜燃料电池

针对近期微能源领域对微型质子交换膜燃料电池的各种应用,特别是在移动电子产品中的应用研究日益受到重视,本文较为详细地介绍了各国、特别是美国、日本和欧洲等国家开展微型燃料电池研发的特点和趋势,并对微型质子交换膜燃料电池研发过程中存在的困难及商业化前景作了简要分析。     

内标-导数红外光谱法定量测定甲硫氨基酸的含量

本文利用内标－导数红外光谱法测定家禽营养限制性氨基酸－－甲硫氨基酸的含量,选择了合适的内标物ＣａＳＯ４,并采用峰高、峰面积、一阶导数、二阶导数等方法,所得的标准曲线方程的相关系数在０．９９４～０．９９８范围之间,结果比较满意。     

溶胶-凝胶法制备掺Sm3+的SiO2玻璃的结构及发光性能

利用溶胶-凝胶技术制备了掺不同量Sm3+和不同退火温度下的SiO2凝胶和玻璃,通过三维荧光光谱、激发光谱、发射光谱的测试,确定了Sm3+在SiO2凝胶玻璃中的最佳激发波长为360 nm,最强发射波长为610 nm,激发光谱的峰位置在360、393、464 nm处,发射光谱的峰位置在578、591、595、610、732nm处,分别归属于4G5/2-6H5/2、4G5/2-6H7/2、4G5/2-6H11/2跃迁,并证明当掺杂量达到1.15%时,Sm3+的发光最强,当Sm3+的掺杂量超过1.15%时,发生浓度猝灭效应.     

Electrochemical biosensor for amplified detection of Pb2+ based on perfect match of reduced graphene oxide–gold nanoparticles and single-stranded DNAzyme

Analytical and Bioanalytical Chemistry - In this study, a sensitive amplification strategy for Pb2+ detection using reduced graphene oxide (RGO) and gold nanoparticles (AuNPs) was proposed....     

Deformation of copper-filled single-walled boron-nitride nanotubes under axial compression

The buckling behaviors of copper–filled single-walled boron-nitride nanotubes (BNNTs) under axial compression are studied by molecular mechanics simulations. This study shows that the stability of this composite nanostructure (Cu@BNNT) gets better with the decrease of the tube diameter. An obvious decrease of the strain energy and vdW energy is observed at the onset of the global compressive buckling. Comparison of the axial compressing behavior between the Cu@BNNT(7,7) and Cu@BNNT(11,11) reveals that they have different buckling deformation and energy loss. Moreover, the stability of a BNNT filled with larger number of atoms is better than the one filled with small number of atoms.     

激光辐照对MgB_2超导体电子结构的影响

研究了光辐照对MgB2超导体电子结构的影响。对MgB2超导体进行不同时间的激光照射后,利用正电子湮没技术对光照样品进行了研究,根据正电子寿命谱参数的变化情况,对光辐照后MgB2超导体样品中缺陷及电子结构的变化进行了讨论。实验表明:MgB2超导体中的平均电子浓度对激光的照射十分敏感,并随光照时间的增加而增加。