Yb:Er:Tm:LiTaO3的上转换发白光性能研究

980 nm脉冲激光激发下,首次通过高温固相法制备Yb(10%):Er(1%):Tm(1%):LiTaO3(摩尔分数)多晶粉并实现室温上转换白光.X射线粉末衍射测试结果表明,Yb:Er:Tm:LiTaO3中的掺杂离子并没有改变晶格结构,以取代的方式存在于钽酸锂晶格中.结合功率曲线测试结果和上转换机制研究发现,产生上转换蓝光的Tm3+离子1G4态的布居主要来自双光子同时吸收过程.而单光子上转换输出的红光,则由Tm3+和Er3+离子之间的交叉弛豫过程产生,即3F2/3(Tm3+)+4I15/2(Er3+)→3H6(Tm3+)+4I9/2(Er3+).上转换绿光来源于Yb/Er离子对的二次能量传递.     

Er:Yb:KGW激光晶体生长及缺陷研究

采用顶部籽晶(TSSG)法生长ErYbKGW晶体.通过研究助熔剂的种类、组成与溶质的比例关系对晶体生长的影响,设计了合理的工艺条件转速30～40 r·min-1;拉速1～2 mm·d-1;降温生长速率0.05 ℃·h-1;降温速率15 ℃·h-1;生长周期15～20 d.通过对晶体缺陷的观察分析认为,晶体裂缝及包裹物等缺陷与生长工艺条件密切相关,应尽量减少生长过程中的温度、浓度及生长速度的波动,保持晶体的稳态生长.     

河北省特级教师:李颖

李颖,女,1959年11月出生,中国共产党员．河北省特级教师,石家庄市专业技术拔尖人才,中学高级教师,现任河北省石家庄市桥东区教育局教研室主任、化学教研员,中国教育学会河北省化学专业委员会理事,中国化学会会员。     

Pendant polymer:amino-β-cyclodextrin:siRNA guest:host nanoparticles as efficient vectors for gene silencing

A novel siRNA delivery vector has been developed, based on the self-assembly of monosubstituted cationic β-CD derivatives with a poly(vinyl alcohol)MW27kD (PVA) main-chain polymer bearing poly(ethylene glycol)MW2000 (PEG) and acid-labile cholesterol-modified (Chol) grafts through an acid-sensitive benzylidene acetal linkage. These components were investigated for their ability to form nanoparticles with siRNA using two different assembly schemes, involving either precomplexation of the pendant Chol-PVA-PEG polymer with the cationic β-CD derivatives before siRNA condensation or siRNA condensation with the cationic β-CD derivatives prior to addition of Chol-PVA-PEG to engage host:guest complexation. The pendant polymer:amino-β-CD:siRNA complexes were shown to form nanoparticles in the size range of 120-170 nm, with a slightly negative zeta potential. Cell viability studies in CHO-GFP cells shows that these materials have 10(3)-fold lower cytotoxicities than 25 kD bPEI, while maintaining gene-silencing efficiencies that are comparable to those of benchmark transfection reagents such as bPEI and Lipofectamine 2000. These results suggest that the degradable Chol-PVA-PEG polymer is able to self-assemble in the presence of siRNA and cationic-β-CD to form nanoparticles that are an effective and low-toxicity vehicle for delivering siRNA cargo to target cells.     

徐僖:中国塑料之父

徐僖,被誉为“中国塑料之父”,是我国著名的高分子材料学家。作为科研工作者,他为我国建设了第一家塑料工厂,创办了中国高校第一个塑料专业,开创了高分子力化学新方向,助推了国防工业和石油开采;作为教育工作者,他出版了中国高等工科院校第一本高分子教科书《高分子物化学原理》,用自己严谨治学的科学态度培养了大批优秀人才。本文通过回顾徐僖先生的求学经历和科研历程,重点介绍了徐僖为我国塑料工业、国防工业、教育教学事业做出的卓越贡献。     

1:1 and 1:2 Inclusion Complexes of Di-tert-butyl l-tartrate with α-Cyclodextrin: A Diffusion Study

The diffusion properties at two overall compositions of a ternary aqueous system containing α-cyclodextrin and a double-functional guest molecule, namely di-tert-butyl l-tartrate, have been studied by means of the Gouy interferometry. The experimental data are interpreted in terms of two independent chemical equilibria involving inclusion compounds. The elements of the diffusion coefficient matrix have been expressed as functions of the two equilibrium constants as well as of the diffusivities of the actual species occurring in solution. The reliability of the diffusion coefficients obtained through the Fujita–Gosting–Revzin procedure is also discussed in terms of its dependence on the composition of solutions used in the Gouy experiments.     

ChemInform Abstract: Thorium Fluorides ThF,ThF2, ThF3, ThF4, ThF3(F2), and ThF5‐ Characterized by Infrared Spectra in Solid Argon and Electronic Structure and Vibrational Frequency Calculations.

Laser‐ablated Th atoms are reacted with different F₂ concentrations to produce ThF_x (x = 1, 2, 3, 4), ThF₃(F₂) and ThF₅^‐.     

ChemInform Abstract: Quantum‐Chemical Calculations and IR Spectra of the (F2)MF2 Molecules (M: B,Al, Ga,In, Tl) in Solid Matrices: A New Class of Very High Electron Affinity Neutral Molecules.

The new class of neutral adduct molecules (F₂)MF₂ (M: B, Al, Ga, In, Tl) forms by reaction of laser‐ablated group 13 metal atoms with F₂ in excess Ar and Ne during condensation at 5 K.     

ChemInform Abstract: The Characterization of Molecular Boric Acid by Mass Spectrometry and Matrix Isolation IR Spectroscopy.

Molecular H₃BO₃ is obtained by heating crystalline orthoboric acid in vacuo to ∼ 40 °C. The IR spectrum of this species isolated in low-temp.     

ChemInform Abstract: Spectroscopic and Electrochemical Characterization of 18-Molybdodisulfate(VI)(4-), S2Mo18O4- 62.

The chemical and physicochemical properties of the yellow Dawson-type molybdosulfate anion S₂Mo₁₈O₆^4-2 in solution are investigated, regarding to the optimum formation conditions, UV-VIS characteristics, and electrochemical behavior.     

ChemInform Abstract: Dimers and Tetramers of SiCl in a Molecular Beam from a Heterogeneous,Intermediate-Pressure Reactor.

Unusual molecules like Si₂Cl₂ and Si₄Cl₄ can be detected by mass spectrometry in a molecular beam extracted from a promising new type of source.     

ChemInform Abstract: From an Icosahedron to a Plane: Flattening Dodecaiodo‐dodecaborate by Successive Stripping of Iodine.

Electrospray ionization‐ion‐trap mass spectrometry shows that B₂I₁₂^2‐ converts to an intact B₁₂ cluster by successive stripping of single iodine radicals or ions.     

ChemInform Abstract: Polychloride Monoanions from [Cl3]‐ to [Cl9]‐: A Raman Spectroscopic and Quantum Chemical Investigation.

Polychloride monoanions [Cl_n]^‐ (n = 3, 5, 7, 9) stabilized by quaternary ammonium salts are obtained through the addition or condensation of an excess of dry chlorine to [NMe₄]Cl, [NEt₄]Cl, [NPr₄]Cl, or [NBu₄]Cl and characterized by Raman spectroscopy and state‐of‐the‐art quantum chemical calculations up to the CCSD(T) level.     

ChemInform Abstract: Electronic Spectra of the Solvated Cations of Chromium(III) and Manganese(II) in Anhydrous Hydrogen Fluoride.

The UV/VIS spectra of Cr(OH₂)₆³⁺ and Mn(OH₂)₆²⁺ in H₂O and of Cr(FH)₆³⁺ and Mn(FH)₆²⁺ in anhydrous HF are recorded.     

ChemInform Abstract: Aromatic Metal‐Centered Monocyclic Boron Rings: Co@B‐8 and Ru@B‐9.

Co@B^‐₈, Ru@B^‐₉, Co@B₈, and Ru@B₉ clusters are characterized by photoelectron spectroscopy and DFT calculations.     

ChemInform Abstract: Matrix Infrared Spectroscopic and Theoretical of the Difluoroamino Metal Fluoride Molecules: F2NMF (M: Cu,Ag, Au).

The title molecules are obtained from spontaneous reactions of coinage metals and NF₃ in solid Ar and Ne matrices.