Near-infrared emissions with widely different widths in two kinds of Er-doped oxide glasses with high refractive indices and low phonon energies

Er³⁺-doped alkali-barium-bismuth-tellurite (LKBBT) and alkali-barium-bismuth-gallate (LKBBG) glasses with high refractive indices and low phonon energies have been designed, fabricated, characterized and compared. Intense 1.53 μm emissions with widely different widths in the two kinds of glasses were observed and recorded under 980 nm diode laser excitation. The full-widths at half-maximum of the 1.53 μm emission bands in LKBBT and LKBBG glasses are 58 and 40 nm, and the lifetimes of them were measured to be 3.21 and 3.97 ms, respectively. The quantum efficiencies for the ⁴I_13/2 level in both glasses are almost 100%. The 1.53 μm broad and narrow emissions with high spontaneous emission probabilities and large emission cross-sections indicate that Er³⁺-doped LKBBT and LKBBG glasses are suitable materials in developing broadband optical amplifier and infrared laser, respectively.     

Ascoli-Arzelà type theorem for rational iterations on the complex projective plane

For a dominant algebraically stable rational self-map of the complex projective plane of degree at least 2, we will consider three different definitions of the Fatou set and show the equivalence of them (Ascoli-Arzelà type theorem). As a corollary, it follows that all Fatou components are Stein. This is an improvement of an early result by Fornæss and Sibony.

     

有机过氧化物安定性的差示扫描量热测定

1 引言有机过氧化物是一种自反应性物质.这类物质在制造、使用、贮存过程中或由于自分解发热、热积累导致燃烧、爆炸,或由于冲击、摩擦、电火花、明火等外部作用导致燃烧爆炸而造成人员伤亡.差示扫描量热法(DSC)、压力容器试验法(PVT)是评价这类物质安全性的基本方法.本文利用DSC法对7种有机过氧化物进行了加热分解试验研究,探讨其热安定性、发生热爆炸的难易程度及剧烈程度.     

On selfinjective semiprimary rings

In this note, we use a universal algebraic argument to show that modules with 0-limits need not be equationally compact, thus providing a counter-example to an open problem of Jensen and Lenzing.     

Investigation of individual micrometer-size Kosa particle with on-site combination of electron microscope and synchrotron X-ray microscope.

The Kosa (yellow sand) aerosol affects the global environment as well as human health because it migrates from the interior of China to other areas, absorbing various atmospheric elements. Investigation into individual Kosa aerosol particles, which are submicroscopic to several tens of micrometers in diameter, is required to resolving the issue. We installed a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectrometer (EDX) on a synchrotron radiation (SR) beam line and introduced the SR beam into the SEM chamber for combinatorial application of SEM-EDX and SR X-ray fluorescence (SR-XRF) spectrometry to individual particles. It should be noted that detailed topographic observation by SEM and sensitive elemental analysis by SR-XRF, both crucial for individual particle measurement but which previously had to be carried out separately, were jointly performed inside the SEM chamber in this setup. Here, we show that SR-XRF results, in conjunction with SEM images, contributed toward resolving individual particle dispositions. Atmospheric sulfur primarily adheres to calcium in the aerosol particles and the particle surface roughens as a consequence of the chemical reaction between the two elements.     

Laccase‐catalyzed polymerization of lignocatechol and affinity on proteins of resulting polymers

For the synthesis of a new biologically functional polymer from a natural resource by an environment‐friendly method, the laccase‐catalyzed polymerization of a lignin‐based macromonomer, lignocatechol, was carried out for the first time in ethanol–phosphate buffer solvent system to give crosslinked polymers in good yields. Lignocatechol was prepared by the phase separation system of lignin and catechol in aqueous sulfuric acid. The copolymerization was also performed with urushiol to afford the corresponding copolymers in high yields. The polymerization mechanism was estimated by the IR and pyrolysis GC‐MS measurements, suggesting that the polymerization proceeded mainly at the catechol ring through a quinone radical intermediate. The thermal properties were measured by the DSC, TG, and TMA analyses, indicating that the polymers had high thermal stabilities because of the crosslinked structures. In addition, it was found that the resulting polymers had the affinity of bovine serum albumin (BSA) and glucoamylase. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 824–832, 2009     

Extreme point axioms for closure spaces

A pair (X,τ) of a finite set X and a closure operator τ:2^X→2^X is called a closure space. The class of closure spaces includes matroids as well as antimatroids. Associated with a closure space (X,τ), the extreme point operator ex:2^X→2^X is defined as ex(A)={p|p∈A,p∉τ(A-{p})}. We give characterizations of extreme point operators of closure spaces, matroids and antimatroids, respectively.     

Optical and electronic properties of siloxane-bridged cyclic dimers with naphthylene or pyrenylene moieties

The optical and electronic properties of novel siloxane-bridged cyclic dimers with naphthylene (CD1) or pyrenylene (CD2) moieties are described. CD1 and CD2 were obtained by the cyclic dimerization of 1,4-bis(dimethylhydroxysilyl)naphthalene (M1) and 1,6-bis(dimethylhydroxysilyl)pyrene (M2), respectively. CD1 and CD2 mainly exhibited the emission from their excimers owing to their short distances between aryl moieties in CD1 and CD2, which were determined to be 3.44 Å and 3.41 Å by the X-ray crystallographic analysis, respectively. The absorption spectra of CD2 in the presence of 7,7,8,8-tetracyanoquinodimethane (TCNQ) revealed that CD2 has the ability to form 1:1 charge-transfer complex with TCNQ, indicating the existence of the transannular π-π interaction between closely located pyrene components in CD2.