Modeling and calculation of thermal explosion time to ignition of cylindrical fireworks and crackers

To analyze the thermal safety of cylindrical fireworks and crackers in storage and transportation, this article establishes a physical model and a mathematical model of thermal explosion time to ignition of finite cylindrical fireworks and crackers. And in order to simplify the thermal explosion model, effective Biot number about boundary condition is deduced according to the theory of heat transfer. The partial differential equation of thermal explosion model are calculated with difference method in Matlab program, to obtain the time to ignition as well as the temperature–time history before explosion system explodes. The rationality of effective Biot number and calculation method is proved through comparison of calculation solution and literature solution. Being the first to solve the problem of two-dimensional thermal explosion unsteady-state model of fireworks and crackers, where the upper surface, lower surface, and side surface have different heat dissipation conditions. Meanwhile, calculation steps were shown about a type of fireworks.     

Vesicle formation in aqueous mixture of the cetyltrimetylammonium bromide and an anionic chitosan derivative

The present work aimed at research the physic-chemical properties of the interaction of N-decyl-O-chitosan sulfate (an amphiphilic chitosan derivative, C₁₀-OCHS) with cetyltrimetylammonium bromide (CTAB) by the steady-state fluorescent, static/dynamic surface tension, turbidity and transmission electron microscopy (TEM). The results showed that the complex of C₁₀-OCHS/CTAB had high surface activity and lower critical aggregation concentration. Besides, the C₁₀-OCHS/CTAB could self-assemble into various aggregates like irregular spherical aggregates, vesicles or polydisperse aggregates from lower to higher concentrations of CTAB with a mixed C₁₀-OCHS concentration of 200?mg/L.     

Full characterization of the embedding relations between α-modulation spaces

In this paper, we consider the embedding relations between any two a-modulation spaces. Based on an observation that the a-modulation space with smaller a can be regarded as a corresponding decomposition space associated with a-covering for larger a, we give a complete characterization of the Fourier multipliers between a-modulation spaces with different a. Then we establish a full version of optimal embedding relations between a-modulation spaces.     

Isatindolignanoside A,a glucosidic indole-lignan conjugate from an aqueous extract of the Isatis indigotica roots

A glucosidic indole-lignan conjugate with a novel carbon skeleton, named isatindolignanoside A (1), was isolated from an aqueous extract of the Isatis indigotica roots “ban lan gen”. Its structure was determined by comprehensive analysis of spectroscopic data, enzyme hydrolysis, and electronic CD calculations. Compound 1 is active against Coxsackie virus B3 and represents the first example of natural product having a structural feature of conjugation between indole and lignan, and its plausible biosynthetic pathway is postulated.     

力学大师S.P.铁木辛柯

S.P.铁木辛柯,20世纪活跃在工程力学领域约60年,培养了几代优秀的工程师和力学家,取得了丰硕的研究成果,推动了工程力学的进展,人们尊之为力学大师.本文从学术生涯、研究成果、学术著作、学术贡献几方面简介铁木辛柯.