Growth and laser properties of Nd<Superscript>3+</Superscript>:Sr<Subscript>6</Subscript>YSc(BO<Subscript>3</Subscript>)<Subscript>6</Subscript> crystal

The crystal of Nd³⁺:Sr₆YSc(BO₃)₆ with dimensions of O 19×42 mm³ was grown by the Czochralski method. It’s spectral and laser properties have been investigated. The absorption cross section is 1.47×10^-20 cm² with a FWHM 12.0 nm at 807 nm, the emission cross section is 1.57×10^-19 cm² at 1060 nm, and the fluorescence lifetime is 76 μs at room temperature. The maximum laser output is 25.7 mJ at 1.06 μm pumped by a single Xenon flash lamp and the overall and average slope efficiencies are 0.12% and 0.09%, respectively. The laser energy threshold value is 1.28 J. PACS 42.55.Rz; 42.70.Hj; 78.20.-e     

无标记DNA在氨基改性导电聚吡咯表面的固定/杂交

通过吡咯(Py)与其衍生物——6-吡咯己胺(PyHA)的共聚物聚(吡咯-co-6-吡咯己胺)[poly(Py-co-PyHA)]的合成研究,并采用电化学循环伏安法来考察体系的电化学活性.在缓冲溶液中,由于探针DNA链上的负电荷与共聚物分子链上的正电荷之间存在强烈的静电吸引力,使得DNA能够固定在导电聚合物膜上.实验结果证明,目标DNA和聚吡咯薄膜之间不存在非特异性吸附,而能和探针DNA进行顺利杂交.此结果为以后研究更为敏感的DNA固定及导电聚合物敏感膜提供了实验基础.     

HClO4–SiO2-catalyzed synthesis of 12-aryl-12H-benzo[i][1,3]dioxolo[4,5-b]xanthene-6,11-diones and 10-aryl-6,7,8,10-tetrahydro-7,7-dimethyl-9H-[1,3]dioxolo[4,5-b]xanthen-9-ones

Abstract  

Three-component one-pot synthesis of some novel 12-aryl-12H-benzo[i][1,3]dioxolo[4,5-b]xanthene-6,11-diones involving treatment of 3,4-methylenedioxyphenol, aldehydes, and 2-hydroxy-1,4-naphthoquinone in presence of HClO₄–SiO₂ was achieved, and this reaction was extended to preparation of 10-aryl-6,7,8,10-tetrahydro-7,7-dimethyl-9H-[1,3]dioxolo[4,5-b]xanthen-9-ones by three-component reaction of 3,4-methylenedioxyphenol, aldehydes, and dimedone.     

Optical spectroscopy, 1.5 μm emission and up-conversion properties of Er-doped Li3Ba2Gd3(MoO4)8 crystal

Er³⁺:Li₃Ba₂Gd₃(MoO₄)₈ crystal has been grown from a melt of Li₂MoO₄ by the top seeded solution growth method (TSSG). The polarized spectral properties of Er³⁺:Li₃Ba₂Gd₃(MoO₄)₈ crystal were investigated and the spectroscopic parameters were calculated and analyzed based on the Judd-Ofelt (J-O) theory. The emission cross-sections were calculated by the Fuchtbauer-Ladenburg (F-L) equation and the peak values of the emission band at 1535 nm were 9.7×10⁻²¹, 7.9×10⁻²¹ and 8.4×10⁻²¹ cm² for E∥b, E∥D1 and E∥D2, respectively. Under 977 nm excitation five up-conversion fluorescence bands around 490, 530, 550, 660 and 800 nm were observed, and the possible up-conversion mechanisms were proposed.     

Characterization and biochemical investigation of the potential inositol monophosphate phosphatase involved in bacterial mycothiol biosynthesis

Abstract

Mycothiol (MSH) is the predominant form of small molecule thiols produced by actinomycetes and plays a pivotal role in the bacterial detoxication process. The only enzyme involved in MSH biosynthesis that has not been characterized yet is a phosphatase MshA2, which was proposed to catalyze the hydrolysis of 3-phospho-1-D-myo-inosityl-2-acetamido-2-deoxy-α-D-glucopyranoside (GlcNAc-Ins-3-P) to GlcNAc-Ins. In this study, a new inositol monophosphate phosphatase from Corynebacterium glutamicum, designated as Cg0911, was discovered, expressed and characterized. Detailed biochemical studies on Cg0911 revealed that GlcNAc-Ins-3-P was its preferred substrate for efficient conversion into GlcNAc-Ins.     

Conditional Lie Bäcklund Symmetries and Sign-Invariants to Quasi-Linear Diffusion Equations

Consider the 1+1-dimensional quasi-linear diffusion equations with convection and source term u _t =[ u ^m ( u _x ) ⁿ ] _x + P ( u ) u _x + Q ( u ) , where P and Q are both smooth functions. We obtain conditions under which the equations admit the Lie Bäcklund conditional symmetry with characteristic η= u _xx + H ( u ) u ² _x + G ( u )( u _x )^{2− n} + F ( u ) u ^{1− n} _x and the Hamilton–Jacobi sign-invariant J = u _t + A ( u ) u ^{n +1} _x + B ( u ) u _x + C ( u ) which preserves both signs, ≥0 and ≤0, on the solution manifold. As a result, the corresponding solutions associated with the symmetries are obtained explicitly, or they are reduced to solve two-dimensional dynamical systems.     

吡咯烷酮酸性离子液体中硼酸酯的催化合成

研究了硼酸与频哪醇和环己醇在离子液体1-甲基-2-吡咯烷酮硫酸氢盐（[Hnmp]HSO4）、1-丁基-3-甲基咪唑四氟硼酸盐（[Bmim]BF4）及1-丁基-3-甲基咪唑六氟磷酸盐([Bmim]PF6)中生成2-环己氧基-4,4,5,5-四甲基-1,3,2-二氧硼烷的酯化反应。 考察了不同离子液体、反应温度、反应时间和离子液体与反应物物质的量比等对反应的影响。 结果表明,当n(硼酸)∶n(频哪醇)∶n(环己醇)∶n([Hnmp]HSO4)=1∶1∶1∶1,反应温度为70 ℃和反应时间为4 h时,硼酸酯的产率为72.5%,离子液体重复使用4次,催化活性无明显降低。     

Spectral Convergence for Degenerating Sequences of Three Dimensional Hyperbolic Manifolds

For degenerating sequences of three dimensional hyperbolic manifolds of finite volume, we prove convergence of their eigenfunctions, heat kernel and spectral measure.