Preparation of nanosheet polyethylene with heterogeneous metallocene catalyst and formation mechanism of nanosheet polyethylene

Silica with small and regular pore sizes was synthesized by hydrothermal crystallization and investigated with thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, N2 adsorption-desorption, and scanning electron microscopy (SEM). The ethylene polymerization was carried out with the silica-supported metallocene catalyst, and the morphology of the resultant polyethylene was investigated with SEM. It was found that the silica could break up into sheet fragments instantaneously during polymerization and the polyethylene could replicate it to obtain nanosheet polyethylene. A possible formation mechanism of the nanosheet polyethylene is proposed.     

Separation and identification of compounds in Adinandra nitida by comprehensive two-dimensional liquid chromatography coupled to atmospheric pressure chemical ionization source ion trap tandem mass spectrometry

A comprehensive two-dimensional liquid chromatographic (2D-LC) separation system based on the combination of a CN column and a Merck Chromolith Flash reversed-phase column was developed for the separation of components in Adinandra nitida, one type of traditional Chinese medicine (TCM). The two dimensions were connected by a ten-port, dual-position valve controlled automatically by software written in-house. The effluents were detected by both ultraviolet and atmospheric pressure chemical ionization source ion trap tandem mass spectrometry (MS). The calculated peak capacity of the 2D-LC–MS/MS system was above 1240. More than 57 components were resolved in the methanol extract from Adinandra nitida leaves, and five of these were identified based on their relative retention times, molecular weights and MS/MS spectra.     

Laser diode pumped LNYAB self-frequency-doubling lasers

The LNYAB self-doubling laser pumped by (LD) has been developed for the first time. The properties of the lasers are much better than those of NYAB self-doubling lasers pumped by LD. The LNYAB self-doubling laser pumped by LD can be operated in TEM_(00) mode with threshold pumping power of 3.6mW which is lower than that of LD pumped NYAB self-doubling lasers by 74%. The output power is 29mW at 0.531μm in green region with optical-to-optical efficiency of 4.8% which is higher than that of NYAB self-doubling laser by 20%.     

Preparations on Several GRIN Lenses

Gradient index materials have been developed from glass melting process to GRIN lenses. Two kinds of GRIN lenses have been fabricated by ion-exchange and glass fusion/diffusion. The main applications to GRIN lenses are demonstrated.     

一种五波长半导体激光生物组织辐照仪

采用GaAlAs单量子阱半导体激光器和LD泵浦的Nd:YVO4－KTP倍频激光器等研制了国内首台可从光导纤维输出5种波长的半导体激光生物组织辐照仪,该仪器已在激光生物医学领域投入应用．     

Preparation of uniform rhodamine B-doped SiO2/TiO2 composite microspheres

Uniform rhodamine B (RB)-doped SiO₂/TiO₂ composite microspheres with catalytic and fluorescent properties were prepared by an easy and economical method in this paper. The composite microspheres were built up with well-dispersed silica particles as the cores, RB as both the doped agent and stabilizer, and the TiO₂ shells were obtained through the hydrolysis of TiCl₄ in water bath. The morphology and structure of the particles were characterized by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The characterization results indicate that composite particles are all in spherical shape and have a narrow size distribution. The composite particles calcined above 500 °C reveal clear crystalline reflection peaks of the rutile TiO₂ which exhibits well catalytic property. The photocatalytic experiment was carried out in order to examine the catalytic property of composite microspheres. The fluorescent property of particles was also investigated. Dye-leakage test indicates that RB molecules entrapped in the composite particles by this method are stable inside the particles.     

PMD mitigation using 3R regeneration based on EAM with wavelength conversion

Polarization mode dispersion (PMD) mitigation is performed using an optical 3R (re-amplification, re-shaping, re-timing) regenerator based on electro-absorption modulator (EAM) with wavelength conversion.System performance without and with 3R regeneration was separately studied by eye analysis and bit-error rate (BER) measurements. The signal quality was significantly improved by 3R regeneration under serious first order PMD (up to 40% of the bit interval) combined with second order PMD (up to about 520 ps2).The PMD mitigation margin of the proposed method is also investigated by measuring the sensitivity at BER 10-10. Further studies indicate that 3R regenerators have the potential to combat with the effects of PMD combined with polarization dependent loss (PDL) and polarization hole-burning (PHB).     

Passive compression of KrCl excimer laser pulses in naphthalene solutions

The width of KrCl laser pulses has been compressed from 5.2 ns to less than 800 ps using naphthalene as the saturable absorber dye. It was found that the width of the compressed laser pulse decreased with both the input laser intensity and the concentration of naphthalene in the solution. The pulse shortening mechanism is attributed to excited state S₂-S_n transitions in naphthalene.     

希土水杨酸与8─羟基喹啉三元配合物研究

合成了六种希土（ＲＥ）－水杨酸（Ｈ２ｓａｌ）－８－羟基喹啉（Ｈｈｑ）三元固体配合物，其通式为ＲＥ（Ｈｓａｌ）２·ｈｑ（ＲＥ＝Ｙ，Ｌａ，Ｎｄ，Ｓｍ，Ｈｏ，Ｅｒ）．通过元素分析、摩尔电导、ＩＲ、Ｆａｒ－ＩＲ、ＵＶ－Ｖｉｓ、ＴＧ－ＤＴＡ分析，研究了配合物的组成、性质和成键特性．通过抑菌试验表明配合物对于霉菌具有抑真菌能力．     

Peakons and periodic cusp wave solutions in a generalized Camassa–Holm equation

By using the bifurcation theory of planar dynamical systems to a generalized Camassa–Holm equation

m_t+c₀u_x+um_x+2mu_x=-γu_xxx