Soft magnetization of a semi-hard/soft magnetic bilayer produced by oblique-incidence evaporation

The possibility of achieving soft magnetization in semi-hard magnetic films such as Fe, Fe_93.5Si_6.5, Fe₅₀Co₅₀ and Fe₇₀Co₃₀ is investigated by depositing films on an Fe₂₀Ni₈₀ underlayer by oblique-incidence evaporation. The magnetic anisotropy of the underlayer is strengthened to a depth of several lattice parameters by vapor deposition of the film at an oblique angle to the substrate surface. This method also allows magnetic anisotropy to be induced in strongly isotropic semi-hard magnetic overlayers to a thickness of a few thousands Angstroms. The coercive force of bilayer films measured along the hard-axis is reduced remarkably by this process, and the strength of the anisotropy field is demonstrated to be readily controllable. When magnetic anisotropy exists in both magnetic layers, a significant change is observed in the magnetization processes of the semi-hard magnetic layer and the coercive forces in the hard magnetization direction is dramatically reduced. Soft magnetization of the semi-hard magnetic layer cannot be achieved when magnetic anisotropy exists in only one of the magnetic layers.     

Observing the Stimulated Raman Gain Spectra of Solutions Using an Infrared Pump Pulse with Narrow Linewidth and a Low-Noise CW Probe Laser

Stimulated Raman gain (SRG) spectroscopy using infrared pump pulses with narrow linewidth and a low-noise cw probe infrared laser was proposed. High-resolution Raman spectra of solutions were obtained. The SRG spectra of crystal GaP, benzene, and toluene were measured to confirm the spectral resolution and sensitivity over the terahertz (THz) region. We discuss the polarization dependence of the spectral measurement of carbon tetrachloride. Our system can detect organic molecules in aqueous solutions.     

Determination of indium by graphite furnace atomic absorption spectrometry after coprecipitation with chitosan.

A sensitive and simple method for the determination of trace amounts of indium in water samples by graphite furnace atomic absorption spectrometry (GFAAS) after coprecipitation with chitosan was investigated. Indium was quantitatively preconcentrated from water samples by coprecipitation with chitosan at pH 7.0-9.0. The coprecipitant was easily dissolved with acetic acid, and indium in the resulting solution was determined by GFAAS. The addition of lanthanum as a chemical modifier was more effective for the atomic absorbance of indium. The detection limit (S/N > or = 3) for indium was 0.04 microg dm(-3), and the relative standard deviations (n = 5) were 3.5-4.5% at 1.0 microg/100 cm3. The results obtained in this study indicate that the proposed method can be successfully applied to the determination of trace indium in water samples.     

添加碳元素合成化学计量比LiNiO2

本文采用添加碳元素、葡萄糖及使用多种试剂为原料的合成方法,合成了具有化学计量比的LiNiO2.分析了这些方法在合成反应中的作用,同时给出了合成LiNiO2的最佳反应条件.     

A Pretreatment Method for GC–MS Determination of Endocrine Disrupting Chemicals in Mollusk Tissues

Automatic soxhlet extraction followed by silica gel cartridge cleanup process was developed as a pretreatment method for GC–MS determination of seven endocrine disrupting chemicals in mollusk tissues. Operation parameters including extraction time, adsorption flow rate and elution flow rate were optimized as 140 min, 2 mL min^?1 and 2 mL min^?1, respectively. Thirty percent dichloromethane in n-hexane and 70% dichloromethane in n-hexane were used as elution solvents in turn. Recovery rates were 93.7, 91.7, 84.5, 83.3, 88.4, 81.2, and 79.7% for nonylphenols (NPs), bisphenol A (BPA), 17α-ethynylestradiol (EE2), estrone (E1), 17α-estradiol (17α-E2), 17β-estradiol (E2), and estriol (E3), respectively. Acceptable relative standard derivations ranged from 8.5 to 12.1%. Method detection limits ranged from 0.27 to 0.68 ng g^?1 dry weight (dw), and quantitative detection limits ranged from 0.62 to 1.26 ng g^?1 dw. The method was successfully applied to five mollusk species in Dapeng Bay of China to verify its practicability, and NPs, BPA, EE2, E1 and 17α-E2 were detected in the range from 1.6 to 131.5 ng g^?1 dw.     

A simple, iron-catalyzed, pyridine-assisted hydrogen peroxide epoxidation system

A simple and inexpensive system comprised of H(2)O(2)-pyridine-FeCl(3)·6H(2)O for the catalysis of olefin epoxidation was established. Intriguingly, the reactivity of this system greatly depends on the amounts of pyridine. Various substrates, including aromatic and aliphatic olefins, were epoxidized by this simple system in moderate to excellent yields.     

DNA-templated assembly of naphthalenediimide arrays

π-Stacked naphthalenediimide (NDI) arrays are of interest as charge-transport materials. We have designed and synthesized an NDI derivative with two Zn(II)-cyclens that act as receptors for the thymine base in DNA. UV/Vis and CD spectroscopy, gel filtration, and molecular-modeling studies have shown that the bis(Zn(II)-cyclen)-NDI can be assembled in the presence of oligo-dT to form π-stacked NDI arrays. The assembly of the NDI arrays was found to be dependent on the length of the oligo-dT and the temperature. The NDI-oligo-dT assembly on a gold substrate exhibits photocurrent responses due to electron transfer through the π-stacked array.     

Sterically congested, "roofed" β-iminodisulfides as new chiral ligands for palladium-catalyzed, asymmetric allylic alkylation

The preparation of a new class of "roofed" β-iminodisulfides from sterically congested, conformationally rigid chiral 2-thiazolidinones is described. A functional survey of palladium-catalyzed asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate proved that symmetrical "roofed" β-iminodisulfides are efficient chiral ligands, showing enantioselectivity opposite that associated with chiral "roofed" β-iminothioether ligands.     

Photo-triggered generation of a free thiol group on DNA: application to DNA conjugation

DNA oligomers possessing a 2-nitrobenzyl (NB) protected thiol group have been prepared. The photo-remove of the NB to generate a free thiol group in DNA has been analyzed by using reverse-phase HPLC and denaturing gel electrophoresis. The photo-triggered generation of the thiol function in DNA was applicable in the light-initiated ligation of thiol-modified DNA oligomers and Au–DNA conjugation.