成型压力对CrO2低温输运性质的影响

本文研究了压力对CrO₂样品低温磁输运性质的影响.样品的X射线衍射结果表明(110)峰的相对强度随压力的增加而增大，说明压力对CrO₂针状纳米颗粒有取向的作用.低温时CrO₂样品的电阻和磁阻均随压力的增加而减少.实验结果表明，低温下样品的电导呈现出典型的晶粒间隧穿特征，其Δ值随着压力和磁场的增加而减小，并且Δ随磁场的变化幅度与成型压力有关，成型压力越高，Δ随磁场的变化越小.这些变化可以归因为压力对晶粒间隧穿势垒的调制. 关键词： 磁阻 压力 隧穿 势垒厚度     

Methane sensor based on palladium/MWNT nanocomposites

Methane gas sensor was fabricated based on electrocatalytic properties of the Pd/MWNT nanocomposites on indium tin oxide (ITO)glass substrates.A linear response for methane was obtained in the range of 0-16%(v/v)with a detection limit of 0.167%(v/ v)and R.S.D.of 4.1%.After 100 times sensing or stable stored more than 12 months in atmosphere,unconspicuous measurable decrease was observed.The response time was less than 60s at room temperature and ambient pressure.Some common potential interferents in samp...     

Fe位Al掺杂对Sr2FeMoO6磁结构和磁输运性质的影响

研究了Sr2Fe1-xAlxMoO6(0≤x≤0.30)系列多晶样品的磁学和输运性质.室温X射线衍射谱图的精修结果显示Al3+掺杂没有改变样品的晶格结构,但提高了Sr2FeMoO6晶格的阳离子有序度.5K时样品的磁化曲线说明平均单位分子饱和磁矩随着Al含量的增加而下降,但平均单位Fe离子磁矩却逐渐提高.磁化曲线的拟合结果显示样品内反铁磁相互作用对饱和磁矩的贡献随着Al含量的增加而下降,说明一定量的Fe离子被Al替代后,抑制了样品内Fe-O-Fe反相边界的形成,从而提高了Sr2FeMoO6晶格的阳离子有序度和平均单位Fe离子磁矩.对饱和磁矩的分析表明非磁性Al3+离子掺杂会形成无磁相互作用的Mo-O-Al-O-Mo区,可以将原来较大的Mo-O-Fe亚铁磁区分割成许多小的区域,并且使这些亚铁磁区间的磁耦合作用变弱,从而提高了低场磁电阻效应.阳离子有序度的提高使来源于自旋相关电子在反相边界处散射的高场磁电阻明显降低,导致了样品的磁电阻在x=0.15时达到了最大值.     

Screening of new non-nucleoside reverse transcriptase inhibitors of HIV-1 based on traditional Chinese medicines database

HIV-1 RT is an important target for the treatment of AIDS.There are two major classes of antiviral agents that inhibit HIV-1 RT have been identified,nucleoside RT inhibitors(NRTIs) and non-nucleoside RT inhibitors(NNRTIs).In this report,a noval class of non-nucleoside compound with potential RT inhibitory activity were found from the traditional Chinese medicines database (TCMD) using a combination of virtual screening,docking,molecular dynamic simulations,where results were ranked by scoring function of...     

Selectively colorimetric detection of cysteine with triangular silver nanoprisms

Triangular silver nanoprisms were prepared and applied to make colorimetric detection of cysteine based on our findings that cysteine could lead to the blue shift of the dipole plasmon resonance absorption,but other 19 kinds of natural amino acids could not.Cysteine with a concentration 160 nmol/L can result in a color change that can be discerned with naked eyes.     

FT far IR studies of YBa2Cu3Ox and Ln-Ba-Cu-O superconductor systems

An investigation of FT far IR spectra of YBa₂Cu₃O_x highT _c superconductor and Ln-Ba-Cu-O systems were carried out at room and liquid nitrogen temperature, respectively. It indicated that the intensity of the IR bands reduces dramatically as the samples transform into superconductor. However, reliable spectra can be obtained from the sintered film samples directly.     

聚氨酯与乙酰丙酮铽复合物的相互作用

合成了聚氨酯、乙酰丙酮铽及其复合物. 红外光谱研究结果表明, 铽离子与聚氨酯分子链中的羰基发生了配位作用. 力学性能测试结果表明, 稀土配合物的加入提高了聚氨酯的拉伸强度和断裂伸长等力学性能. 流变性能测试结果显示, 乙酰丙酮铽的加入使聚氨酯溶液的粘度增大, 表明溶液中两者之间存在明显的相互作用.     

皂化酸性磷酸酯萃取稀土离子过程中有机相的FTIR光谱表征

研究了不同浓碱皂化的Ｄ２ＥＨＰＡ－正庚烷体系萃取－系列稀土离子（Ｌａ＾３＋－Ｌｕ＾３＋）放射性的Ｐｍ除外）过程中有机相的ＦＴＩＲ光谱变化规律，结果说明，Ｄ２ＥＨＰＡ萃取稀土离子后，Ｐ－Ｏ基团５的红外吸收频率降低，吸收强度升高，说明Ｐ－Ｏ基团与稀土离子发生配位；红外光谱研究研究结果表明：不同稀土离子与Ｐ－Ｏ配位能力有差别，从Ｌａ＾３＋－Ｓｍ＾３＋ｓｇｎ ｗｕｇ ｃｅｌｔｗｙｅ ｕｑｗ ｆｕｌｊｅ ｓ     

Preparation of fructone catalyzed by water-soluble Brφnsted acid ionic liquids

Fructone(2-methyl-2-ethylacetoacetate-1,3-dioxolane),a flavouring material,has been synthesized from ethyl acetoacetate and glycol using five water-soluble Br(?)nsted acid ionic liquids as catalysts for the first time.The used Br(?)nsted acid ionic liquids include [Hmim]Tfa,[Hmim]Tsa,[Hmim]BF_4,[Bmim]HSO4,[Bmim]H_2PO_4,and[Hmim]BF_4 showed the highest catalytic activity for the preparation of fructone.After reaction,the product could be isolated from the reaction system automatically,and the ionic liquid could be directly reused without dehydration.     

肉豆蔻酸和棕榈酸酸盐体系的振动光谱研究

报道了肉豆蔻酸和榈酸酸盐体系的振动光谱，结果表明，脂肪酸与其碱金属盐之间通过氢键和羧基配位形成酸盐络合物。酸盐体系中氢键具有不同于普通氢键的性质，本文结合振动光谱讨论了酸盐的结构和氢键性质。