西瓜中4种植物生长调节剂残留的分析方法研究

建立了固相萃取/高效液相色谱法测定西瓜中24-二氯苯氧乙酸(24-D)、赤霉素(GA3)、多效唑(PP333)、6-苄氨基嘌呤(6-BA) 4种植物生长调节剂残留的方法.样品用80%甲醇溶液提取,采用Strata C18固相萃取小柱进行富集、净化,以甲醇-0.15%磷酸水溶液为流动相,梯度洗脱,经ZORBAX Ec...     

稀土改质催化剂对废食用油制备燃料油的影响

利用浸渍法制备稀土改质催化剂,用于废食用油脂催化裂解的裂解气催化改质。考察了催化剂活性组分含量、硅铝比、焙烧温度、改质反应温度对产物组成、烯烃含量及收率的影响。得最佳条件:ZSM-5作为催化剂载体,催化剂活性组分镧稀土含量为6%,催化剂焙烧温度为550℃,改质反应温度为360℃。在最佳条件下催化改质,燃料油烯烃含量降低了34.3%,汽油含量提高了14.36%,轻柴油含量提高了1.67%,重柴油含量下降了6.72%,重油含量下降了2.2%,燃料油总收率提高了7.12%,油品质显著提高。     

Common Features in Electronic Structure of the Oxypnictide Superconductors from Photoemission Spectroscopy

High resolution photoemission measurements are carried out on non-superconducting LaFeAsO parent com- pound and various superconducting RFeAs（O1-ZFx） （R=La, Ce and Pr） compounds. It is found that the parent LaFeAsO compound shows a metallic character. By extensive measurements, several common features are identified in the electronic structure of these Fe-based compounds： （1） 0.2 eV feature in the valence band, （2） a universal 13-16 meV feature, （3） near EF spectral weight suppression with decreasing temperature. These uni- versal features can provide important information about band structure, superconducting gap and pseudogap in these Fe-based materials.     

离子迁移谱定量检测复杂基质中新型炸药六亚甲基三过氧化二胺

六亚甲基三过氧化二胺( Hexamethylene triperoxide diamine, HMTD)是一种新型有机过氧化爆炸物,由于原料易得、制备方法简单,常被用于恐怖袭击和犯罪活动中。本实验基于非放射性电离源真空紫外灯( VUV)发展了一种试剂分子辅助灯电离正离子迁移谱技术,通过优化筛选试剂分子,最终选择丙酮作为HMTD定量检测的试剂分子。利用质谱对丙酮的反应试剂离子和HMTD的产物离子进行了离子归属,确定反应试剂离子为丙酮二聚体离子 m/z 117[( CH3)2 CO ]2 H+, HMTD 的产物离子为其质子化的分子离子m/z 209[ HMTD+H]+。在迁移管和热解析温度120℃的条件下,利用HMTD最大信号强度和第10 s的信号强度对其标准样品进行定量检测,线性范围分别为5~50 ng/μL和5~100 ng/μL,检出限分别可达0.2和0.3 ng/μL。化妆品如香水等常常干扰和抑制离子迁移谱测量,发展在香水基质中HMTD的现场快速筛查和检测方法具有现实意义。将这两种定量方法应用于3种不同品牌香水样品中HMTD的定量检测,对比发现利用HMTD第10 s的信号强度进行定量具有较好的回收率和准确性,该方法适用于复杂基质中HMTD的准确快速定量检测。     

Pseudogap and Superconducting Gap in SmFeAs（O1-xFx） Superconductor from Photoemission Spectroscopy

High resolution photoemission measurements are carried out on non-superconducting SmOFeAs paxent compound and superconducting SmFeAs（O1-xFx） （x = 0.12, and 0.15） compounds. The momentum-integrated spectra exhibit a clear Fermi cutoff that shows little leading-edge shift in the superconducting state. A robust feature at 13 meV is identified in all these samples. Spectral weight suppression near IF, F with decreasing temperature is observed in both undoped and doped samples that points to a possible existence of a pseudogap in these Fe-based compounds.     

High-Average-Power Third Harmonic Generation at 355 nm with CsB3O5 Crystal

A 17.7W average power output at 355nm by the third harmonic generation (THG) of 1064nm light has been obtained with the nonlinear optical crystal CsB305 (CBO). The fundamental light source is a diode-pumped Nd:YAG laser with a pulse duration of 70ns and a repetition rate of 7kHz. A CBO crystal cut for type-Ⅱ PM angles is used in the experiment. The THG energy conversion efficiency with CBO is twice as large as that with LBO. As a THG crystal, CBO has better performance than that of LiB305 crystal (LBO).     

电喷雾离子迁移谱检测氨基酸及多肽的研究

建立了氨基酸及多肽的电喷雾离子迁移谱检测方法.采用自制的电喷雾离子迁移谱装置,在室温条件下以甲醇为溶剂,空气为漂移气体,流速为1000 mL/min,电喷液流速为2 mL/min,测试了甘氨酸、胱氨酸、组氨酸、精氨酸4种氨基酸及缓激肽片段(1~7)和P物质2种多肽的离子迁移谱,计算出上述化合物的约化迁移率.离子迁移谱图反映出化合物的结构信息,具有指纹谱特征.此装置在1 min的检测时间内对P物质的检测灵敏度达到855 ng/mL.结果表明,电喷雾离子迁移谱可用于氨基酸及多肽类化合物的现场快速鉴定.     

纳升电喷雾-离子迁移谱及其与高效液相色谱的联用

搭建了一套纳升级电喷雾-离子源离子迁移谱仪。首先,分别对尾吹气流速、溶剂流速等影响仪器去溶剂化效果的参数进行了研究和优化。在此基础上,用一系列胺类化合物对该仪器的去溶剂化效果、分辨能力以及灵敏度进行了表征。实验结果表明,该仪器能够对电喷雾离子液滴实现完全去溶剂化;三辛胺的检出限可以达到10 μg/L。最后,将该仪器用作高效液相色谱的检测器,在无需衍生化的条件下对胺类混合物样品进行检测。由三乙胺、二乙胺以及丁胺组成的混合样品被成功分离并测定。该系统对三乙胺、二乙胺以及丁胺的线性响应范围均达到近两个数量级。     

Sixth Harmonic of A Nd：YVO4 Laser Generation In KBBF for ARPES

We report that a deep ultraviolet （DUV） laser from the sixth harmonic of a 1064nm laser has been firstly used as light source in an ultrahigh energy-resolution angle-resolved photoemission spectroscopy （ARPES）. The wavelength is 177.3nm obtained by using the second harmonic KBe2BO3F2 crystal with a frequency tripled 1064nm Nd：YVO4 laser. The large flux （10^14 - 10^15 photons/s） and narrow line width （0.26 meV） are suitable for the ultrahigh-energy resolution ARPES. The laser-ARPES can be a powerful tool to study the electronic structure at and near the Fermi level of the superconductor and correlated materials. The laser-ARPES has worked more than 500 h already.