茂丰(6%抗坏血酸水剂)对辣椒增产效果研究

研究茂丰对辣椒的增产效果、结果表明绿色新农药茂丰6％抗坏血酸水剂1500～2000倍溶液600～750kg／hm^3,茎叶喷雾辣椒2—3次,改善品质,可增产10～30％,是辣椒“优质生产”理想的药剂。     

Synthesis and molecular structure of 2,4,8a-triaryl-6-methylperhydro[1,3,2]dioxaborinino[5,4-c]pyridines

Condensation of arylboronic acids with 4-hydroxy-3-(-hydroxybenzyl)-1-methyl-4-phenylpiperidine afforded 2,4,8a-triarylperhydro[1,3,2]dioxaborinino[5,4-c]pyridines. The molecular structure of 6-methyl-2,4,8a-triphenylperhydro[1,3,2]dioxaborinino[5,4-c]pyridine was established by X-ray diffraction analysis.     

Influence of octadecyl dihydrogen phosphate on the formation of active super-fine calcium carbonate

A carbonation process for the synthesis of active super-fine calcium carbonate particles from Ca(OH)(2) slurry at room temperature using a CO(2)-N(2) gas mixture was investigated. Industrial octadecyl dihydrogen phosphate (A) was added as a size-controlling additive and modifier in different reaction periods according to the pH of the medium. Analysis of the reaction products led to the conclusion that the addition of A in the digestion period could inhibit the crystal growth of calcium carbonate, while the addition of A at pH 7 of the medium could modify the surface character of the calcium carbonate particle, which was found to exhibit hydrophobic properties. From transmission electron microscopy (TEM), the hydrophobic property was attributed to the deposition of calcium alkyl phosphates, produced in the reaction mixture, onto the surface of calcium carbonate particle. IR spectra and TGA analysis of the obtained products indicated that A was bound onto the crystalline CaCO(3).     

一阶中立型时滞微分方程的振动性

研究了具有正负系数的一阶中立型时滞微分方程[x(t)-px(t-τ)] qx(t-σ)-rx(t-ρ)=0,其中p∈(0,1),利用适当的特征方程和不等式,建立了解的新振动准则。     

Silica nanoparticle is a possible safe carrier for gene therapy

In order to develop a safe and effective gene therapy carrier, some toxicological and biodynamical experiments were carried out on silica nanoparticles （SiNPs）. First we prepared SiNPs with appropriate portions of cyclohexane, deionized water and ethyl silicate, and then transfected the modified SiNPs and GFP plasmid DNA complex into the HT1080 cells to test the effectiveness of transfection for gene therapy. At the same time, we injected the SiNPs into a number of mice through tail vein. Then we made the mice crossed to evaluate the acute, long-term and reproductive toxicity. In vivo distribution analysis and pathological examination were made on both adult mice and their offspring. SiNPs were uniform and had an average diameter of 40 nm, and the modified SiNPs carried exogenous DNA molecules into target cells and the transferred GFP fusion gene was effectively expressed in the cells. The SiNPs injected via tail vein were widely distributed in almost all of tissues, and the injected mice had the ability to reproduce normally. The in vivo and in vitro results of this study clearly show that SiNPs can be used as a safe and effective carrier for gene transfection and gene therapy.     

Coexistence of two bifurcation regimes in a closed ferroin-catalyzed Belousov-Zhabotinsky reaction

The ferroin-catalyzed Belousov-Zhabotinsky (BZ) reaction was studied in a batch reactor under anaerobic conditions and was found to evolve through two separated regimes of complex oscillations. Significantly, the two bifurcation regimes exhibited qualitatively different dependence on compositions of the reaction mixture, i.e., initial concentrations of bromate, sulfuric acid, malonic acid, and ferroin. The reaction temperature also showed opposite effects on the two bifurcation regimes, in which complexities of the first bifurcation regime were enhanced while oscillations in the second bifurcation regime became simpler as a result of decreasing temperature. Numerical simulations with a 12-variable model developed specifically for the ferroin-BZ system were able to reproduce transient complex oscillations observed in experiments. These calculations further illustrated that reactions such as ferroin and HOBr, ferroin and HBrO2, and ferriin and Br- were not essential in describing complex dynamics of the ferroin-BZ reaction.     

Sorption of Na+, Ca2+ ions from aqueous solution onto unbleached kraft fibers-kinetics and equilibrium studies

The sorption of Na+ and Ca2+ from aqueous solutions onto unbleached kraft fiber was investigated. The sorption kinetics was found to be highly dependent on pH, initial concentration, and temperature. The sorption rate increased as the initial concentration and pH were increased. Thermodynamic and kinetic results indicated that the sorption of Na+ and Ca2+ onto kraft fiber was exothermic, reversible, and spontaneous with activation energies of 11.0 and 23.3 kJ/mol, respectively. The sorption kinetics followed a pseudo-second-order model and the equilibrium data followed the Langmuir isotherms. The fiber sorption capacities calculated from the Langmuir isotherms were similar to the fiber charges determined by potentiometric titration at pH > 7.     

Magnetic and transport properties of Cu2MnAl Heusler alloy prepared by rapidly quenched method

The Cu₂MnAl alloy was prepared by rapidly quenched (suction-casting and melt-spinning) methods with various thicknesses of 20, 40 and 1000 μm. The X-ray diffraction (XRD) patterns of the fabricated samples show a single phase of Cu₂MnAl. All the samples reveal soft magnetic behavior with coercivity below 1.6 kA/m and Curie temperature of about 600 K. Resistance of the alloy behaves as a linear function of applied magnetic field. Magnetoresistance (MR) ratio depends on the thickness of the samples and achieves ∼0.8% at the field of 240 kA/m for the sample with thickness of 20 μm. The variation of the properties of the alloy can be interpreted by the difference of energy band structure caused by defects in the alloy.