YZr2OZr3:Er3+纳米晶anti-Stokes发光性质的研究

采用均相沉积法制备了不同Er³⁺离子浓度掺杂的Y₂O₃纳米晶, 应用XRD，SEM和PL光谱对该体系材料进行了表征.在Y₂O₃:Er³⁺纳米材料体系中, 观察和研究了Stokes及anti-Stokes PL谱强度与Er³⁺离子摩尔浓度变化的关系, 当Er³⁺离子浓度为2.0mol%时, anti-Stokes PL强度最强.粉末X 关键词： 氧化钇纳米晶 anti-Stokes PL 双光子吸收     

Studies on the chemical constituents of the South China Sea sponge Phacellia fusca

Three pyrrololactam alkaloids have been isolated from the marine sponge Phacellia fusca Schmidt collected from the South China Sea, and their structures were determined as 1–3 , on the grounds of spectral data. This is the first report of these compounds from this sponge. The structure of 1 was confirmed by X-ray analysis.     

Thermal Behavior of Urea-(D) Tartaric Acid and Urea-(DL) Tartaric Acid Crystals

The thermal behavior of two new non-linear optical (NLO) materials, urea-(D) tartaric acid (UDT) and urea-(DL) tartaric acid (UDLT) were studied by using DSC, TG and TMA. The results show that: 1) The two crystals have different melting points but similar decomposition temperatures due to the influences of intermolecular forces, which is attributed to the stereo effects of (D)-tartaric and (DL)-tartaric acid molecules; 2) There was only thermal expansion and no thermal contraction when the UDT and UDLT crystals were heated; 3) There was no phase transition within the measured temperature range; 4) The thermal expansion of the UDT and UDLT crystals shows a small anisotropy; 5) The specific heats of UDT and UDLT change linearly with temperature in the measured temperature range and the value for UDT is 1.321 J g-1 K-1 at 320 K while the specific heat of UDLT is 1.357 J g-1 K-1 at the same temperature. This revised version was published online in July 2006 with corrections to the Cover Date.     

规范变换与有限维可积系统间的变换

本文表明，利用两个特征值问题的规范变换，不仅可以建立和它们相联系的势的约束之间以及相应的有限维Ｈａｍｉｌｔｏｎ系统间的变换关系式，而且可以由一个可积系统的对合守恒积分导出另一个系统的守恒积分     

Synthesis of optically active poly(N‐propargylsulfamides) with helical conformation

A novel chiral N‐propargylsulfamide monomer ( 1a ) and its enantiomer ( 1b ) were synthesized and polymerized with (nbd)Rh⁺B^?(C₆H₅)₄ as a catalyst providing poly(1) (poly( 1a ) and poly( 1b )) in high yields (≥99%). Poly(1) could take stable helices in less polar solvents (chloroform and THF), demonstrated by strong circular dichroism signals and UV–vis absorption peaks at about 415 nm and the large specific rotations; but in more polar solvents including DMF and DMSO, poly(1) failed to form helix. Quantitative evaluation with anisotropy factor showed that the helical screw sense had a relatively high thermal stability. These results together with the IR spectra measured in solvents showed that hydrogen bonding between the neighboring sulfamide groups is one of the main driving forces for poly(1) to adopt stable helices. In addition, copolymerization of monomer 1a and monomer 2 was conducted, the solubility of poly(1) was improved drastically. However, the copolymerization had adverse effects on the formation of stable helices in the copolymers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 500–508, 2007     

关于严实Hilbert环

在本文中，严实Ｈｉｌｂｅｒｔ环得到了更进一步的刻划．本文的主要结果是：一个环Ａ是严实Ｈｉｌｂｅｒｔ环，当且仅当多项式环Ａ［Ｘ］的每个实极大理想在Ａ上的局限是Ａ的一个极大理想，当且仅当Ａ是实Ｈｉｌｂｅｒｔ环，且Ａ［Ｘ］的每个实极大理想是极大的．     

关于多目标数学规划的最优性条件

本文讨论定义于Ｂａｎａｃｈ空间的多目标数学规划，得到一些ε－最优解和（弱）有效解的必要条件，充分条件和必要充分条件。     

Synthesis and application as polymer electrolyte of hyperbranched polyether made by cationic ring‐opening polymerization of 3‐{2‐[2‐(2‐hydroxyethoxy)ethoxy]ethoxymethyl}‐3′‐methyl‐oxetane

A novel cyclic ether monomer 3‐{2‐[2‐(2‐hydroxyethoxy)ethoxy]ethoxy‐methyl}‐3′‐methyloxetane (HEMO) was prepared from the reaction of 3‐hydroxymethyl‐3′‐methyloxetane tosylate with triethylene glycol. The corresponding hyperbranched polyether (PHEMO) was synthesized using BF₃·Et₂O as initiator through cationic ring‐opening polymerization. The evidence from ¹H and ¹³C NMR analyses revealed that the hyperbranched structure is constructed by the competition between two chain propagation mechanisms, i.e. active chain end and activated monomer mechanism. The terminal structure of PHEMO with a cyclic fragment was definitely detected by MALDI‐TOF measurement. A DSC test implied that the resulting polyether has excellent segment motion performance potentially beneficial for the ion transport of polymer electrolytes. Moreover, a TGA assay showed that this hyperbranched polymer possesses high thermostability as compared to its liquid counterpart. The ion conductivity was measured to reach 5.6 × 10^?5 S/cm at room temperature and 6.3 × 10^?4 S/cm at 80 °C after doped with LiTFSI at a ratio of Li:O = 0.05, presenting the promise to meet the practical requirement of lithium ion batteries for polymer electrolytes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3650–3665, 2006     

Simultaneous electrochemical determination of uric acid and ascorbic acid on a glassy carbon electrode modified with cobalt(II) tetrakisphenylporphyrin.

A cobalt(II) tetrakisphenylporphyrin (Co(II)TPP) film modified glassy carbon electrode (Co(II)TPP-GCE) was prepared by just coating Co(II)TPP solution on the surface of the electrode. It can be used for the simultaneous determination of ascorbic acid and uric acid. The anodic peaks of AA and UA can be separated well. Owing to the strongly hydrophobic property of porphyrin, the modified electrode has good stability and long life. The linear range for UA and AA were 2.0 x 10(-6)-1.0 x 10(-4) M and 9.0 x 10(-6)-2.0 x 10(-3) M with detection limits of 5.0 x 10(-7) and 5.0 x 10(-6) M, respectively. Furthermore, metalloporphyrins of other kinds were also used to construct modified electrodes. Their performances were inferior compared with that of the Co(II)TPP modified electrode.