Synthesis and Characterization of Pr（DPM）3 Served as Precursor for MOCVD

Praseodymium β-diketone chelate, Pr(DPM)3 [DPM=2,2,6,6-tetramethyl-3,5-heptanedionato], was successfully synthesized from the inorganic salt praseodymium chloride and HDPM(2,2,6,6-tetramethyl-3,5-heptane-dione) in an ethanol/aqueous solution followed distillation at low pressure and recrystallization from toluene. The physical and thermal properties of the chelate, including volatility, stability, and thermal decomposition, were investigated by elemental analyses, 1H NMR spectroscopy, XRD, TG/DTG/DTA analysis, infrared spectroscopy, and mass spectroscopy. The chelate with high purity prepared by thes of this study also shows sufficient volatility and stability in inert gases, which could be used as the precursor for metal-organic chemical vapor deposition(MOCVD).     

替代M-型钡铁氧体纳米粒子的微波吸收性能

The microwave-absorbing behavior of substituted M-type barium ferrite nano-particles was investigated. The nano-particles were synthesized with coprecipitation-melted salt method. For the purpose of comparison, corre-sponding micro-particles were also prepared through direct coprecipitation and sintering. XRD and TEM of the nano-particles showed that the ferrite was hexagonal in structure and widely distributed in size with particle size being less than 100nm, the complex permittivity and permeability of a 1.50mm thick specimen and a 1.40mm thick specimen containing 60% by weight of substituted M-type barium ferrite nano-particles and micro-particles were measured respectively in X band (8.2～12.4GHz) range, from which the reflection loss (R.L.) of microwaves was calculated and two comparative absorption curves were given. The results showed that the synthetic nano-particles could well absorb microwaves in X band. The absorption was larger than 10dB in the range of 9.2～12.4GHz while the maximum absorption was 38.6dB at 10.6GHz.     

聚硅氧烷/甲基丙烯酸甲酯核壳结构复合粒子的制备

聚硅氧烷/甲基丙烯酸甲酯核壳结构复合粒子的制备;种子乳液聚合;核壳结构     

多孔软硬磁Ni0.5Zn0.5Fe2O4/SrFe12O19复合纤维制备及吸波性能

通过静电纺丝技术制备了多孔软硬磁Ni_(0.5)Zn_(0.5)Fe_2O_4/SrFe_(12)O_(19)复合纤维,利用综合热重分析仪(TG-DSC)、X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线能谱仪(EDS)和矢量网络分析仪(VNA)等对复合纤维的晶体结构、微观形貌和电磁性能进行了表征,研究了不同软硬磁质量比对纤维结构和性能的影响。结果表明:900℃下制备的复合纤维具有立体多孔结构,软硬磁质量比为1∶3时,复合纤维的比表面积达到55 m~2·g~(-1)。吸波性能测试结果显示,当吸波剂涂层厚度为3.5 mm时,复合纤维在10.6 GHz处反射损失(RL)值达到-31.9 dB,在2~18 GHz频率范围内,RL值小于-10 dB的吸收带宽达到10.5 GHz,覆盖了整个X波段(8.2~12.4 GHz)和Ku波段(12.4~18 GHz),显示出优异的宽波段吸收性能。     

基于L-苹果酸铜锌配位聚合物的合成和结构表征

以L-苹果酸为配体,并分别以2,2′-联吡啶和菲咯啉为辅助配体,合成了3个过渡金属配位聚合物{[Zn(mal)(2,2′-bipy)]_2·5H2O}_n(1)、{[Zn(mal)(Phen)(H_2O)]_2·3H_2O}_n(2)和{[Cu(mal)(Phen)]_2·4H_2O}_n(3)(H_2mal=L-苹果酸,2,2′-bipy=2,2′-联吡啶,Phen=菲咯啉),采用X射线衍射技术分别测定了3个配合物的单晶结构,并进行了元素分析、粉末XRD衍射、红外光谱等研究。结果表明配合物1和2均属于正交晶系,空间群均为P2_12_12_1,通过L-苹果酸根桥联金属中心形成一维链结构,2条平行链之间以面对面的方式重叠及通过吡啶环或菲咯啉环之间的π-π弱相互作用形成梯状双链结构;而配合物3属于单斜晶系,空间群为P21,并通过L-苹果酸根桥联Cu(Ⅱ)金属中心及菲咯啉π-π弱相互作用形成双链二维层状结构。     

以在线开放课程为核心进行一流课程的建设与实践

The development and integration of information technology with higher education facilitate the construction of the first-class online course, which has been a key objective for undergraduate education reform. Based on the student-centered idea, it is a valuable exploration and practice to integrate the online course with traditional teaching, and make efforts on innovative digitized teaching mode by taking the advantage of information technology.     

质谱在高通量快速检测技术中的应用研究进展

质谱是现代分析测试技术中同时具备了灵敏度高、特异性好、分析速度快等特性的普适性方法,现已被广泛应用于食品检验、环境监测、药物筛选、临床医学等众多领域的高通量快速检测技术中。该文针对近年来低分辨质谱、高分辨质谱以及原位电离质谱技术在高通量快速检测,特别是小分子化合物的高通量快速检测中的应用研究进展进行了综述,并对质谱技术用于高通量快速检测的发展趋势及应用前景进行了展望,以期为相关领域的科技人员提供理论支持和技术参考。     

用压强传感器展示压强对二氧化氮与四氧化二氮平衡体系的影响

利用自制木制固定器、注射器等设计实验装置,借助压强传感器展示压强对"2NO2?N2O4"平衡体系的影响,实验操作简单,直观地展现了平衡移动过程,对于学生学习化学平衡尤其是理解勒夏特列原理有很大的帮助。     

枸杞组分特征检测及产地溯源技术研究进展

特色农产品的特征组分检测和溯源技术是政府职能部门进行市场监管和地理标志产品保护的重要手段。该文介绍了色谱技术(高效液相色谱及凝胶渗透色谱)、质谱及其联用技术(气相色谱-质谱联用技术及液相色谱-质谱联用技术)、红外光谱技术(傅立叶变换红外光谱及近红外光谱)、电感耦合等离子体原子发射光谱技术和电感耦合等离子体质谱技术在枸杞有机化学成分和矿质元素检测中的应用以及枸杞溯源技术的研究进展,并简要概述了其中应用较多的化学计量学方法。旨在为不同产地枸杞的质量控制和来源追溯提供参考,进而推动我国枸杞消费市场的良性发展。     

FORMATION OF MULTI-BRANCHED DOMAINS IN GARNET BUBBLE FILMS BY LOW-BIAS-PULSE METHOD

The formation of multi-branched domains( MBDs) at low static bias field was first studied. With multiple branches, MBDs contain more or less same-signed vertical-Bloch-lines (VBLs) in their walls, Experiments. on four samples have shown that under certain conditions, the amount and hardness of the MBDs formed can be easily controlled, and so-called "low-bias-field method" is another effective way to form VBL chains. It was found that MBDs are formed due to the expansion of domain segments after compressed by a rectangular bias pulse. The number of VBLs nucleated in domain walls is affected by the space where the domains expand rapidly.