The Action of the Selenomorpholine Compounds on Escherichia coli Growth by Microcalorimetry

The action of three kinds of the selenomorpholine compounds on a strain ofEscherichia coli was studied by microcalorimetry. Differences in their capacities to affect the metabolism of this bacterium were observed. The extent and duration of the effect on the metabolism as judged from the rate constant (k) of Escherichia coli (in log phase) varied with the different drugs. The kinetics show that selenomorpholine compounds had an effect on the metabolism process of Escherichia coli. The k of Escherichia coli in the presence of the drugs increased with the increasing concentrations of the drugs (C) at low concentration; but at high concentration, the rate constant decreased with the increasing concentrations of the drugs. The experimental results reveal that the sequence of antibiotic activity of selenomorpholines is: N-selenomorpholinemethyl succinimide and its hydrochloride>N-(α-selenomorpholinebenzyl) succinimide. This revised version was published online in August 2006 with corrections to the Cover Date.     

Fabrication of beta-Ni(OH)2 and NiO hollow spheres by a facile template-free process

Ni(OH)2 hollow microspheres with beta-Ni(OH)2 nanosheets as the in situ formed building units were fabricated via a novel template-free approach in a strong alkaline solution of glycine, and can be converted into NiO hollow microspheres by a thermal decomposition process.     

Temperature Dependence of the Mössbauer Effect on Prussian Blue Nanowires

Highly ordered Prussian blue nanowires with diameter of about 50 nm and length up to 4 m have been fabricated by an electrodepositing technology with two-step anodizing anodic aluminum oxide films. The Mössbauer spectra taken between 15 and 300 K indicate that the hyperfine parameters decrease as the temperature increases. The temperature dependence of the quadrupole splitting, the isomer shift and the spectra area are discussed. A decrease of Debye temperature for Prussian blue nanowires was found with respect to that of Prussian blue bulk.     

Excited state structural dynamics and Herzberg–Teller coupling of tetraphenylporphine explored via resonance Raman spectroscopy and density functional theory calculation

Resonance Raman spectra of free-base tetraphenylporphine (TPP) were obtained with 397.9, 416, and 435.7 nm excitation wavelengths and density functional calculations were done to elucidate the electronic transitions and the resonance Raman spectra (RRs) of TPP. The RRs indicate that the Franck–Condon region photodynamics for S₀ → S₄ electronic state is predominantly along the C_m–ph stretch while that for S₀ → S₃ electronic state is predominantly along the porphin ring C_βC_β stretch. Non-totally symmetric vibrational modes were regularly presented in resonance Raman spectra: the shorter the excitation wavelengths were, the stronger intensity the modes had, which can be interpreted in terms of electric dipole transition moments caused by Franck–Condon and Herzberg–Teller coupling.Four non-total symmetry vibrational mode υ_52, υ₆₄, υ₉₇ and υ₁₃₀ in A₂ irreducible representative of TPP were observed in 397.9, 416 and 435.7 nm resonance Raman spectrum. With the shorter wavelength laser excitations at 416 or 397.9 nm, the A₂ vibrational modes show more enhanced Raman intensity by comparison with those in the TPP spectrum excited at 435.7 nm.     

Resonance Raman intensity analysisof the excited‐state photochemical dynamicsof dimethyl 1,3‐dithiole‐2‐thione‐4,5‐dicarboxylate in the A‐band absorption

Dimethyl 1,3‐dithiole‐2‐thione‐4,5‐dicarboxylate (DDTD) was synthesized and characterized using NMR, Fourier transform (FT)‐Raman, Fourier transform‐infrared (FT‐IR) and UV spectroscopies. Resonance Raman spectra (RRs) were obtained with 341.5, 354.7 and 368.9 nm excitation wavelengths and density functional calculations were carried out to elucidate the π (S C S) →π* (S C S) electronic transitions and the RRs of DDTD in cyclohexane solution. The RRs indicate that the Franck–Condon region photo dynamics have a multidimensional character with motion predominantly along the CS stretch and the C S symmetric stretch modes in the five‐member heterocycle. A preliminary resonance Raman intensity analysis was carried out and the results for DDTD were compared with previously reported results for 1,3‐dithiole‐2‐thione (DTT). Differences and similarities of the spectra in terms of molecular symmetry and electron density are also discussed. Copyright © 2010 John Wiley & Sons, Ltd.     

Ru single atoms induce surface-mediated discharge in Na-O2 batteries

Sodium（Na）O₂ batteries have high energy density and low cost. However, high polarization, complex discharge products, and low Coulombic efficiency（CE） lead to poor cyclability. Here, we proposed an atomically dispersed Ru catalyst on nitrogen-doped graphene for Na-O₂ batteries. The catalysts enable the discharge to proceed via a surface-mediated route, which leads to uniform deposition of Na_2-xO₂ and low polarization during recharge. The first-principl...     

Size and shape effects on magnetic properties of Ni nanoparticles

Pure Ni nanoparticles ranging in size from 24 to 200 nm are prepared via thermal decomposition of nickel acetylacetonate in oleylamine. The as-prepared Ni particles change from spherical to dendritic or starlike with increasing precursor concentration. The particles are stable because the organic coating occurs in situ. Magnetic measurement reveals that all the Ni nanoparticles are ferromagnetic and show ferromagnetic–paramagnetic transitions at their Curie points. The saturation magnetization M_s is size-dependent, with a maximum value of 52.01 and 82.31 emu/g at room temperature and 5 K, respectively. The coercivity decreases at first and then increases with increasing particle size, which is attributed to the competition between size effect and shape anisotropy. The Curie temperature T_c is 593, 612, 622, 626 and 627 K for the 24, 50, 96, 165 and 200 nm Ni nanoparticles, respectively. A theoretical model is proposed to explain the size-dependence of Ni nanoparticle Curie temperature.     

Hyperchaos synchronization of fractional-order arbitrary dimensional dynamical systems via modified sliding mode control

This paper considers the design of adaptive sliding mode control approach for synchronization of a class of fractional-order arbitrary dimensional hyperchaotic systems with unknown bounded disturbances. This approach is based on the principle of sliding mode control and adaptive compensation term for solving the problem of synchronization of the unknown parameters in fractional-order nonlinear systems. In particular, a novel fractional-order five dimensional hyperchaotic system has been introduced as a representative example. Furthermore, global stability and asymptotic synchronization between the outputs of master and slave systems can be achieved based on the modified Lyapunov functional and fractional stability condition. Simulation results are provided in detail to illustrate the performance of the proposed approach.     

Large-scale synthesis and magnetic properties of cubic CoO nanoparticles

We present the synthesis, microstructural and magnetic characterization of cubic CoO nanoparticles with well-controlled size and shape. The as-synthesized CoO nanoparticles are stable because of the organic coating that occurred in situ. The Néel temperature is 225 and 280 K for the 42 and 74 nm CoO particles, respectively. The CoO nanoparticles exhibit anomalous magnetic properties, such as large moments, coercivities and loop shifts. These results provide evidence for the formation of spin compensated random system in CoO. The structurally distorted and magnetically disordered surface layer ferromagnetic phase played an important role in the magnetic behavior of CoO nanoparticles. The smaller is the particle size, the stronger is the contribution of the ferromagnetic phase and the more is the surface layer helpful to enhance the observed coercivity and the exchange bias.     

高分辨偏正拉曼光谱对丙酸酐C=O振动模的拉曼光谱非一致效应研究

根据C=O振动的各向同性和各向异性拉曼光谱和红外光谱特点讨论研究了丙酸酐分子的局部有序排列以及振动耦合机理. 利用三级联共聚焦拉曼光谱仪测定了不同浓度丙酸酐的各向同性与各向异性拉曼光谱图, 分别采集了丙酸酐在四氯化碳和甲醇中的光谱以及不同极性溶剂中的光谱, 具体分析了丙酸酐C=O振动模的浓度效应、 溶剂效应以及拉曼光谱非一致效应(NCE). 结果表明, 丙酸酐C=O振动模的NCE效应随着浓度的降低而减小; 随着溶剂极性的减小而增加. 利用密度泛函理论的B3LYP-D3/31-311G(d,p)基组计算了丙酸酐单体和二聚体的几何稳定构型, 用聚集态理论模型解释了丙酸酐分子的NCE效应、 浓度效应与溶剂效应. 理论计算结果与实验结果相吻合.