PrP_5O_(14)的晶体结构与铁弹畴

本文用X射线衍射方法研究了PrP_5O_(14)的晶体结构和铁弹相变。晶体空间群为P2_1/c,晶胞参数a=8.777(1)A,b=9.029(2)A,c=13.068(2)A,β=90.35°(1),z=4,最终R值为0.046。在130±5℃转变成正交晶系,空间群为P_(ncm),a=8.813(7)A,b=9.075(2)A,c=13.119(10)A。高温相变使晶体产生了铁弹性孪晶,室温下晶体属mmmF2/m类铁弹体。

Ce_xGd_yTb_(1-x-y)P_5O_(14)晶体生长及其光谱

采用蒸发溶液法从磷酸溶液中生长出一系列Ce_xGd_yTb_(1-x-y)P_5O_(14)晶体.测定了它们的结构.它们属于单斜晶系,空间群P2_(1/c).测定了Ce_(0.9)Gd_(0.1)P_5O_(14)、Ce_(0.9)Tb_(0.1)P_5O_(14)和La_(0.8)Gd_(0.1)Tb_(0.1)P_5O_(14)等晶体的光谱.首次观察到,将Gd加入Ce_xTb_(1-x)P_5O_(14)晶体中形成.Ce_xGd_yTb_(1-x-y)P_5O_(14)时阻碍了Ce~(3+)→Tb~(3+)的能量传递,导致Ce~(3+)的发射峰增强,Tb~(3+)的~5D_4—~F_J发射峰减弱、而~5D_3—~7F_J发射峰增强.

Ce_xGd_(1-x)P_5O_(14)晶体生长及其光谱特性

在研究五磷酸铈晶体中Ln~(3+)对Ce~(3+)发光的影响中观察到加入Gd~(3+)后能使发光有所增强,Gd~(3+)在Ce~(3+)敏化体系中的发光是当前发光领域中的前沿课题。为此我们用蒸发溶液法生长了一系列的Ce_xGd_(1-x)P_5O_(14)晶体。所得晶体的X射线衍射分析表明,Ce_xGd_(1-x)P_5O_(14)与CeP_5O_(14)具

DETERMINATION OF TRACE AMOUNT OF 14 RARE-EARTH IMPURITIES IN HIGH-PURITY YTTRIUM-OXIDE WITH ICP-AES

A method of analysis of high purity yttrium oxide with ICP-AES was described with emphasis on the study of Y_2O_3 matrix effects. The results showed that the line intensities of ana]ytes decreased with the increase of Y_2O_3 concentration in solution because of following factors. (1) The presence of matrix resulted in the decrease of the amount of analytes reaching ICP. (2) Matrix Y_2O_3 entering the plasma decreased the excitation temperature of the plasma and depressed the ionization of analytes in the pl...

NdP_5O_(14)晶体的光谱强度参数

关于高稀土浓度化学计量比的稀土五磷酸盐晶体已为人们所熟知，国内外NdP_3O_(14)晶体已用作微小型激光器的工作物质。但对稀土五磷酸盐晶体的光谱参数报告得不多。我们生长

Er_(3x)~(3+):Y_(3-3x)Al_5O_(12)和Er_x~(3+)Yb_(1-x)P_5O_(14)晶体的光谱强度参数

本文报道了用J-O理论计算的Er_(3x)~(3+):Y_(3-3x)A_5O_(12)和Er_x~(3+)Yb_(1-x)P_5O_(14)两种晶体中Er~(3+)五种浓度的振子强度、Ω_λ参数、辐射跃迁几率与荧光分支比。并观察了这些参数的变化规律。

Ce_(0.9)RE_(0.1)P_5O_(14)晶体中Ce~(3+)的发光寿命研究

利用时间相关单光子计数方法系统地测定了Ce_(0.9)RE_(0.1)P_5O_(14)晶体中Ce~(3+)的发光寿命。发现荧光寿命数值能够较好地说明双掺晶体中除Ce而外的其它稀土离子对Ce~(3+)的发光强度的增强或猝灭现象。

YP_5O_(14):Er~(3+),Tm~(3+)晶体的合成

研究了水热法合成晶体,浓度配比、生长温度对晶体生长习性的影响.合成了一系列化学计量比的Y_(1-x-0.3)Er_(0.3)Tm_xP_5O_(14)(x=0.01～0.1)晶体,观察和分析了晶体的缺陷及成因,测定和讨论了晶体结构.

Ho~(3+)离子及HoP_5O_(14)晶体的光谱性质

根据HoP_5O_(14)的吸收光谱和荧光光谱,用Judd-Ofelt理论计算了Ho~(3+)的强度参数.并计算了激发能级的辐射跃迁速率、辐射寿命、荧光分支比和积分发射截面等光谱参数.

SmP_5O_(14)晶体中Sm~(3+)离子的能级和晶场参数

本文利用光谱方法测定了SmP_5O_(14)晶体中Sm~(3+)离子的能级,通过拟合定出晶场参数,利用这些参数所计算的能级和实验能级符合得很好。

Sm_xLa_(1-x)P_5O_(14)和Dy_xY_(1-x)P_5O_(14)晶体的荧光寿命研究

本文用脉冲衰减法和时间分辨荧光光谱法测量了六种不同稀土离子浓度的Sm_xLa_(1-x)P_5O_4晶体的~4G_(5/2)→~6H_J(J=5/2,7/2,9/2,11/2)四个能级和七种不同稀土离子浓度的Dy_xY_(1-x)P_5O_(14)晶体的~4F_(9/2)→~6H_J(J=15/2,13/2,11/2,9/2)四个能级的荧光寿命和荧光强度。结果指出,在这类晶体中,Sm~(3+)和Dy~(3+)的荧光寿命随着离子的浓度增加而变短,存在着严重的荧光浓度猝灭现象。最后还讨论了浓度与寿命,寿命与荧光强度的关系。

Ce_(0.9)Yb_(0.1)P_5O_(14)晶体的光电压光谱

前文在研究五磷酸铈晶体中Ln~(3+)对Ce~(3+)发光强度的影响时,发现当加入少量的Eu~(3+)和Yb~(3+)离子到CeP_5O_(14)晶体中能使Ce~(3+)的发射产生严重的猝灭现象,以致于用Ce~(3+)的302nm吸收带激发晶体时,观察不到Ce~(3+)的发射,或者十分微弱。令人费解的是Yb~(3+)离子在紫外和可见区无吸收带,Yb~(3+)离子的加入应该成为一个稀释离子,现却使Ce~(3+)的发射产生严

控制气氛光谱法测定纯氧化钬中14个稀土杂质元素

本文介绍的是:使溶液干渣样品在Ar/O_2气氛中交流电弧激发,以基体钬为内标,测定高纯氧化钬中微量稀土杂质。其被测元素的测定下限是:铕、镱和钇各为0.0004％,镧、钐、铒,镝和铥各为0.0016％,铈、钕、钆和铽各为0.0031％,镨和镥各为0.0063％,相对标准偏差均小于7.1％。

Cytoglobosins A-G, Cytochalasans from a Marine-Derived Endophytic Fungus, Chaetomium globosum QEN-14

Financial support from the Ministry of Science and Technology of China (2010CB833802 and 2007AA09Z446) and from the National Science Foundation of China (30910103914) is gratefully acknowledged.

Cloning and sequencing of the phycocyanin gene from Spirulina maxima and its evolutionary analysis (vol 14, pg 307, 2002)

The geneswere cloned for the two apoprotein subunits, alpha and beta, of phycocyanin from the cyanobacterium Spirulina maxima (=Arthrospira maxima) strain F3. The alpha- and beta-subunit gene-coding regions contain 489 bp and 519 bp, respectively. The beta-subunit gene is upstream from the alpha-subunit gene, with a 111-bp segment separating them. Similarities between the alpha-subunits of S. maxima and nine other cyanobacteria were between 58% and 99%, as were those between the beta-subunits. The maximum similarity between the alpha- and beta-subunits from S. maxima was 27%.