La212型化合物的合成,结构与性能

研究了总结了近十年Ｌａ ２１２型化合物的合成，结构与超导性能，合成了稀土元素、碱金属元素Ｎａ、ｋ以及Ａｇ替代形成的新的Ｌａ２１２型化合物。     

新化合物La_(2-x)Sr_xCa_(0.5)Pr_(0.5)Cu_2O_6的合成、结构与电磁性质研究

合成了Ｌａ２１２型新化合物Ｌａ２－ｘＳｒｘＣａ０．５Ｐｒ０．５Ｃｕ２Ｏ６;发现Ｓｒ对Ｌａ的替代量为０．４～１．１。通过ＬＡＺＹ程序结构研究发现该化合物具有典型Ｌａ２１２型化合物的晶体结构。     

新化合物La2—xSrxCa0.5Pr0.5Cu2O6的合成,结构与电磁性质研究

合成了Ｌａ２１２型新化合物Ｌａ２－ｘＳｒｘＣａ０．５Ｃｕ２Ｏ６；发现Ｓｒ对Ｌａ的替代量为０．４－１．１。通过ＬＡＺＹ程序结构研究发现该化合物具有典型Ｌａ２１２型合物的晶体结构。     

M(Pr,Ag)替代的La212型化合物的相变和晶体结构

用固态反应法制备了Ｍ（Ｐｒ,Ａｇ）替代的Ｌａ２１２型化合物,发现Ｌａ２－ｘＳｒｚＣ０．５Ｐｒ０．５Ｃｕ２Ｏ６,Ｌａ１７６Ｐｒ０．４Ｃａ１－ｘＰｒ２Ｃｕ２Ｏ６和Ｌａ２－ｘＰｒｘＣａ０．５Ｓ０。．５Ｃｕ２Ｏε单相范围的ｘ值分别是０．４－１．１,０－０．５和０－１．５。     

镧化合物催化合成醋酸异戊酯

考察了含镧化合物对醋酸异戊醋合成的催化活性，实验结果表明：三者的活性顺序为Ｌａ－Ｙ型分子筛〉ＬａＣｌ３〉Ｌａ２Ｏ３〉Ｌａ２Ｏ３．Ｌａ－Ｙ型分子筛具有稳定的重复催化活性。     

草酸铵在铝酸镧和铝酸铈的前驱体合成中的应用

用硝酸镧、硝酸铈铵和硝酸铝分别溶于草酸铵水溶液中，干燥后所得前驱体经磨粉和压片，在６００℃和７００℃温度下焙烧分解，合成了具有钙钛矿型结构的ＬａＡｌＯ３和ＣｅＡｌＯ３化合物粉末．Ｘ射线衍射和ＤＳＣ分析结果推断前驱体的脱水、分解、中间体形成及转变为ＬａＡｌＯ３和ＣｅＡｌＯ３多晶相是个多步复杂过程．此类软化学方法的运用大大降低了这些化合物的合成温度．     

钙钛矿型LaMO_3系列对CO_2甲烷化反应的催化性能研究

合成了稀土复合含氧化合物ＬａＭｎＯ３,ＬａＣｏＯ３,ＬａＣｒＯ３。利用ＸＲＤ测定了其晶体结构,进行了ＣＯ２甲烷化的催化活性测试,对其反应机理进行了分析,并认为属于表面上的反应。     

Meyer反应的相化学及其合成设计

研究了ＣｓＢｒ与ＲＥＢｒ＿３（ＲＥ＝Ｌａ，Ｐｒ）在氢溴酸介质中反应的四元体系的相化学关系发现了５ＣｓＢｒ·２ＲＥＢｒ＿３·２２Ｈ＿２Ｏ型化合物。以相化学关系和热分析等结果，揭示了轻稀土化合物的相似性。同时，设计了新的固相反应，合成了新类型化合物，发展了Ｍｅｙｅｒ合成方法．     

Dawson结构稀土磷钼钨杂多化合物的合成及表征

用嵌入改性法合成了１０种通式为Ｋ１５Ｈ２［Ｌｎ（Ｐ２Ｗ１６ＭｏＯ６１）２］·ｎＨ２Ｏ,Ｌｎ＝（Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｙｂ）的新型稀土杂多化合物,通过元素分析、ＩＲ和ＵＶ测定,证明所合成的１０种化合物同属于Ｄａｗｓｏｎ结构,利用ＴＧ－ＤＴＡ及变温ＩＲ技术考察了该系列化合物的热稳定性．     

La1+zBa2-zCu3Oy相的形成、固溶度及La对Ba的替代

对Ｌａ１＋ｚＢａ２－ｚＣｕ３Ｏｙ相的形成,固溶度和Ｌａ对Ｂａ的替代进行了系统研究,以期获得制备具有更高Ｔｃ的超导体的最佳条件。表明Ｌａ１＋ｚＢａ２－ｚＣｕ３Ｏｙ在空气中固溶度为０．２０－０．７０,Ｎ２中为０。在空气中合成Ｌａ１＋ｚＢａ２－ｚＣｕ３Ｏｙ时,Ｌａ能替代Ｂａ,但Ｂａ并不能替代Ｌａ,空气和Ｏ２有利于Ｌａ对Ｂａ的替代,但当在Ｎ２中合成Ｌａ１＋ｚＢａ２－ｚＣｕ３Ｏｙ时,Ｌａ对Ｂａ的替代受到抑制     

用Ag替代而形成的La212型新化合物的合成、结构与电磁性质研究

用高温固相反应法合成了La2-xAgxCaCu2O6新化合物,找到了最佳合成条件,结构研究表明：新化合物具有典型的La212型化合物晶体结构：La,Ag占有4e位置,Ca占有2a位置,La1.65Ag0.35CaCu2O6的电阻与温度关系表现为金属行为。     

Eu~(3+)激活的La_2Na_2Sr_6(PO_4)_6Br_2和Y_2Na_2Ca_6(PO_4)_6F_2晶体中的发光中心

采用高温固相法合成了La_2Na_2Sr_6(PO_4)_6Br_2和Y_2Na_2Ca_6(PO_4)_6F_2。X射线衍射分析证明它们都为单一物相。用Sr_(10)(PO_4)_6Br_2和Ca_(10)(PO_4)_6F_2同晶指标化法进行指标化,结果表明:它们都属六方晶系的磷灰石结构,空间群为P6_3/m。计算了它们的晶胞参数。以Eu~(3+)做结构探针,研究了Eu~(3+)所处晶格的点对称性。研究表明:在La_2Na_2Sr_6(PO_4)_6Br_2中Eu~(3+)占据4f格位,为C_3点群,而在Y_2Na_2Ca_6(PO_4)_6F_2中Eu~(3+)处于6h格位,为C_6点群。     

乙酸镧与含氮配体混配配合物合成及性质研究

合成了乙酸镧与１，１０—邻菲罗啉、２，２’—联吡啶的混配配合物。通过元素分析、红外光谱、紫外光谱、摩尔电导和热重分析对该配合物进行了表征，与组成式Ｌａ（Ｐｈｅｎ）２（Ａｃ）３和Ｌａ（Ｐｈｅｎ）（ｂｉＰｙ）（Ａｃ）３符合较好。该配合物的抗菌试验表明其具有较强的广谱抗菌活性，并探讨了抗菌活性与配合物结构之间的关系。     

Thermodynamic modeling of the Ge-La binary system

The Ge-La binary system was critically assessed by means of the calculation of phase diagram (CALPHAD) technique. The associate model was used for the liquid phase containing the constituent species Ge, La, Ge₃La₅, and Ge_1.7La. The terminal solid solution diamond-(Ge) with a small solubility of La was described using the substitutional model, in which the excess Gibbs energy was formulated with the Redlich-Kister equation. The compounds with homogeneity ranges, α(Ge_1.7La), β(Ge_1.7La), and (GeLa), were modeled using two sublattices as α(Ge,La)_1.7La, β(Ge,La)_1.7La, and (Ge,La)(Ge,La), respectively. The intermediate phases with no solubility ranges, Ge₄La₅, Ge₃La₄, Ge₃La₅, and GeLa₃, were treated as stoichiometric compounds. The three allotropic modifications of La, dhcp-La, fcc-La, and bcc-La, were kept as pure element phases since no solubility of Ge in La was reported. A set of self-consistent thermodynamic parameters of the Ge-La binary system was obtained. The calculation results agree well with the available experimental data from literatures.     

La(ClO_4)_3·3H_2O与18C6在乙醇中配合行为的研究

采用改进的半微量相平衡方法研究了La(ClO_4)_3·3H_2o—18c6—C_2H_5OH三元体系在25℃时的溶解度,测定了各饱和液相的检光率,结果表明有了三种化学计量的配合物(4La(ClO_4)_3·3(18C6)·12H_2O·9C_2H_5OH;La(ClO_4)_3·18C6·3H_2O·2C_2H_sOH和La(ClO_4)_3·2(18C6)·3H_2O·C_2H_5OH)生成。分离制备了两种配合物,经化学分析测定,确定了配合物的组成为La(ClO_4)_3·18C6·3H_2O与La(ClO_4)_3·2(18C6)·3H_2O;用IR,TG,DTG及电导对配合物进行了研究。     

硼酸根离子在（La，Ce）PO_4：Tb中的作用

（ＢＯ３）３－加入到（Ｌａ，Ｃｅ）ＰＯ４：Ｔｂ中，一方面使Ｃｅ３＋吸收峰位置随（ＢＯ３）３－加入浓度不同有规律性变化，另一方面可以提高材料的热稳定性。本文用Ｘ光电子谱测得了与后者相应的信息，讨论了Ｃｅ（３＋）、Ｃｅ（４＋）的共存，价态数比与（ＢＯ＿３）３￣－的关系，从而解释了影响材料热稳定性机制。     

1-苯基-3-甲基-4-乙酰基吡唑酮-5与1,10菲绕啉对镧(Ⅲ)、钐(Ⅲ)、铒(Ⅲ)的协同萃取

研究了1-苯基-3-甲基-4-乙酰基吡唑酮-5(PMAP或HA)与1,10菲绕啉(Phen或B)对La3+,Sm3+,Er3+的协同萃取行为.用斜率法测定协萃合物的组成为REA3·B,测定HA对La3+,Sm3+,Er3+的pH1/2分别为3.31,2.86,2.61;对固态协萃合物的IR谱进行了讨论.     

Towards understanding the influence of Mg content on phase transformations in the La3-xMgxNi9 alloys by in-situ neutron powder diffraction study

The present work is focused on the studies of the phase-structural transformations in the La_3-xMg_xNi₉ (x ​= ​1.0, 1.1 and 1.2) alloys as active materials of negative electrodes in the Nickel-Metal Hydride (Ni/MH) batteries. The phase equilibria and phase-structural transformations in the alloys were probed by in situ neutron powder diffraction (NPD) at the temperatures ranging from 300 ​K to 1273 ​K using the measurements of the equilibrated alloys at 8 setpoint temperatures of 300, 973, 1073, 1123, 1173, 1223, 1248 and 1273 ​K.Prepared by induction melting initial alloys were found to be multi-phase structured, containing up to 6 individual intermetallic compounds with different stoichiometric compositions. With the increase of the temperature and holding time, various transformations took place in the studied alloys. These included the formations and transformations of super-stacking intermetallics with variable ratios (La ​+ ​Mg)/Ni, 1:3, 2:7 and 5:19.With increasing temperatures, several systematic changes took place. (a) Abundances of (La,Mg)₂Ni₄ AB₂ and (La,Mg)Ni₃ AB₃ type intermetallics gradually decreased before they melted/decomposed above 1073 ​K; (b) The (La,Mg)₂Ni₇ A₂B₇ type intermetallics began to decrease in abundances above 1123 ​K; (c) The transformation in the (La,Mg)₅Ni₁₉ intermetallics from 3R to 2H proceeded above 1223 ​K.The increase of Mg content had no obvious influence on (La,Mg)₂Ni₄ and (La,Mg)₂Ni₇ phases, and corresponding reactions R1 and R3 took place at the same temperatures as in the La–Ni system. However, with increasing Mg content the melting point of (La,Mg)₅Ni₁₉ phase increased while the melting point of the (La,Mg)Ni₃ phase it decreased, leading to the variation of the reaction temperatures of the corresponding processes.The present study will assist in optimizing phase-structural composition of the alloys in the La–Mg–Ni system which contain Mg-modified layered structures by tailoring the high temperature annealing conditions.     

高温超导体(La1-xMx)2CuO4(M=Ba，Sr)的化学键性质和M(o^)ssbauer谱研究

利用复杂晶体化学键电介质的平均能带模型研究了(La_(1-x)M_x)_2CuO_4(M=Ba,Sr)的化学键特性,得到Cu-O键的平均共价性为0.3,La-O键的平均共价性为0.03。应用由共价性和极化率定义的化学环境因子计算了~(57)Fe在La_2CuO_4中的Mossbauer同质异能位移,确定了~(57)Fe在La_2CuO_4中的价态和占位情况。     

Construction and identification of reverse genetics system of Dengue type 2 virus isolated in China

Dengue (DEN) viruses, mosquito-borne pathogens of the Flavivirus genus, Flaviviridae family, are envel- oped RNA viruses that contain a single-stranded, posi- tive-sense, capped RNA genome of approximately 11 kb. Single polypeptide is co-translationlly pr…