非晶态合金催化剂用于二甲基紫脲酸加氢反应

二甲基紫脲酸加氢反应;nicob/白炭黑催化剂;非晶态合金催化剂     

A selective fluorescent probe for La and Y based on calix[6]arene

A new fluorescent probe based on calix[6]arene functionalized with three naphthoic acid groups was synthesized and showed selective fluorescence enhancement in the presence of La³⁺ and Y³⁺. In addition, the fluorescence enhancement behaviors depended on the pH values of the solution.     

Studies of magnetite nanoparticles synthesized by thermal decomposition of iron (III) acetylacetonate in tri(ethylene glycol)

In this paper, water-soluble magnetite nanoparticles have been directly synthesized by thermal decomposition of iron (III) acetylacetonate, Fe(acac)₃ in tri(ethyleneglycol). Size and morphology of the nanoparticles are determined by transmission electron microscopy (TEM) and dynamic light scattering (DLS) measurements while the crystal structure is identified using X-ray diffraction (XRD). Surface charge and surface coating of the nanoparticles are recognized using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectra (XPS) and zeta potential measurements. Magnetic properties are determined using vibrating sample magnetometer (VSM) and superconducting quantum interference device (SQUID) measurements. The results show that as-prepared magnetite nanoparticles are relatively monodisperse, single crystalline and superparamagnetic in nature with the blocking temperature at around 100 K. The magnetite nanoparticles are found to be highly soluble in water due to steric and electrostatic interactions between the particles arising by the surface adsorbed tri(ethyleneglycol) molecules and associated positive charges, respectively. Cytotoxicity studies on human cervical (SiHa), mouse melanoma (B16F10) and mouse primary fibroblast cells demonstrate that up to a dose of 80 μg/ml, the magnetic nanoparticles are nontoxic to the cells. Specific absorption rate (SAR) value has been calculated to be 885 and 539 W/gm for samples with the iron concentration of 1 and 0.5 mg/ml, respectively. The high SAR value upon exposure to 20 MHz radiofrequency signifies the applicability of as-prepared magnetite nanoparticles for a feasible magnetic hyperthermia treatment.     

Crystal Structure of 2-[(P,P-Diphenoxy)phosphono(p-methyl)benzyl]-1, 2-benzisoselenazol-3(2H)-one

The crystal structure of the title compound 2-[(P, P-Diphenoxy)phosphono(p-methyl)benzyl]-1, 2-benzisoselenazol-3(2H)-one, C27H22NO4PSe, was determined by single crystal X-ray diffraction. It crystallizes in the triclinic system, space group P(No. 2) with Mr=534.41, a=9.761(2), b=10.304(2), c=13.396(3), α=110.97(3), β=107.70(3). γ=90.02(3)°, V=1190(1) 3, Z=2, Dx=1.492 g/cm3, λ=0.71073, μ=1.6596 mm-1 and F(000)=544. The structure was solved by direct methods. The final R factor is 0.068 and Rw is 0.074 for 2500 unique observed reflections [I≥3σ(I)]. The results presented herein indicate that the selenium-containing bicyclic moiety is a coplanar structure and that two adjacent molecules are symmetrically linked to each other forming a dimer through the Se(1c)...O=P(1) bonding interaction with an intermolecular Se(1c)...O distance of 2.797 .     

Crystal and Molecular Structure of N-(1-Ethoxycarbonyl- ethyl)1-Ethoxycarbonylmethyl-3-ethyl-1,2,3,4- tetrahydro-4-oxo-1,3,2-benzodiazaphosphorin- 2-carboxamide 2-Oxide

1 INTRODUCTIONOrganophosphorus compounds are ubiquitous in nature and they have broad applications in the fields of agriculture and medicine. During the past two decades, (-ketophosphonates and their derivatives have attracted considerable attention because these compounds are endowed with special physical, chemical and pharmacological properties due to the proximity of the carbonyl and the phosphoryl groups[1～6]. For example, it is well known that phosphonoformic acid (PFA) is effectiv…     

Computer simulation to investigate the FRET application in DNA hybridization systems

Molecular dynamics (MD) and quantum mechanics (QM) were used to investigate fluorescence resonance energy transfer (FRET) between coumarin and ethidium in two Mergny's DNA hybridization systems. By combining the transition dipoles calculated by the quantum semi-empirical method and the conformations of the FRET probes collected by MD, FRET efficiencies were derived from the F?rster equation at five temperatures from 273 K to 313 K. The plotted efficiencies were compared with Mergny's experiments, and showed good agreement. The simulated orientation factor and isotropically averaged orientation factor were compared, and the results demonstrated that the assumption of isotropic orientations is invalid when FRET probes are close to each other. The first order kinetic assumptions were also used to calculate the transfer efficiencies, and the results show that this D-A FRET process approximates the first order kinetic reactions.     

超高精细度光学腔中低损耗的测量

关键词：     

深海内波非线性薛定谔方程的研究

考虑以跃层为界的两层分层流体,在弱非线性条件下,从分层流体的动力学基本方程组出发,应用多重尺度方法推导出描述深海内波的非线性薛定谔方程,分析方程中频散和非线性系数,求出非线性薛定谔方程的孤子解,并通过数值实验验证了理论的正确性.     

Degree of fourth-order coherence by double Hanbury Brownben Twiss detections

Photon quantum statistics of light can be shown by the high-order coherence. The fourth-order coherences of various quantum states including Fock states, coherent states, thermal states and squeezed vacuum states are investigated based on a double Hanbury Brown–Twiss (HBT) scheme. The analytical results are obtained by taking the overall efficiency and background into account.