无碱条件下由芳香醛肟和磺酰氯制备O-磺酰基芳香醛肟

在氧化银和碘化钾存在下,磺酰氯与肟室温反应合成一系列O-磺酰基肟.芳香醛肟和酮肟作为底物,产率56%～87%.不过,对硝基苯甲醛肟、脂肪醛肟及α,β-不饱和醛肟作为该反应底物时,没有获得目标产物.     

Robust adaptive fractional-order observer for a class of fractional-order nonlinear systems with unknown parameters

Nonlinear Dynamics - This paper investigates the parameter and state estimation problems for a class of fractional-order nonlinear systems subject to the perturbation on the observer gain. The...     

α‐Diamine Nickel Catalysts with Nonplanar Chelate Rings for Ethylene Polymerization

A series of novel α‐diamine nickel complexes, (ArNH‐C(Me)‐(Me)C‐NHAr)NiBr₂, 1 : Ar=2,6‐diisopropylphenyl, 2 : Ar=2,6‐dimethylphenyl, 3 : Ar=phenyl), have been synthesized and characterized. X‐ray crystallographic analysis showed that the coordination geometry of the α‐diamine nickel complexes is markedly different from conventional α‐diimine nickel complexes, and that the chelate ring (N‐C‐C‐N‐Ni) of the α‐diamine nickel complex is significantly distorted. The α‐diamine nickel catalysts also display different steric effects on ethylene polymerization in comparison to the α‐diimine nickel catalyst. Increasing the steric hindrance of the α‐diamine ligand by substitution of the o‐methyl groups with o‐isopropyl groups leads to decreased polymerization activity and molecular weight; however, catalyst thermal stability is significantly enhanced. Living polymerizations of ethylene can be successfully achieved using 1 /Et₂AlCl at 35 °C or 2 /Et₂AlCl at 0 °C. The bulky α‐diamine nickel catalyst 1 with isopropyl substituents can additionally be used to control the branching topology of the obtained polyethylene at the same level of branching density by tuning the reaction temperature and ethylene pressure.     

Assessment and distinction of commercial soy protein isolate product functionalities using viscosity characteristic curves

To simplify the assessment method of soy protein isolate（SPI） functionalities,the viscosity and functionalities of commercial SPI products were studied.Viscosity value（y） increases with increasing concentration（x） and exhibits a highly significant correlation with the exponential equation y = a·e^bx.The b values of products are gradually enhanced from dispersion,emulsion and injected to gel type.Products with low b values（<0.2）,and high dispersivity were dispersion-type.Products having high b values （>0.4） and gel springiness were gel-type.The other products with centered b value（0.2-0.4）,high solubility and emulsifying capacity were emulsion-type.     

Hybrid numerical method for wall-resolved large-eddy simulations of compressible wall-bounded turbulence

Acta Mechanica Sinica - Bogies are responsible for a significant amount of aerodynamic resistance and noise, both of which negatively affect high-speed train performance and passenger comfort. In...