A Study of Estimating the Safe Storage Life, Self-accelerating Decomposition Temperature and Critical Temperature of Thermal Explosion of Double-base Propellant Using Isothermal and Non-isothermal Decomposition Behaviours

A method of estimating the safe storage life （τ）, self-accelerating decomposition temperature （TsADT） and critical temperature of thermal explosion （Tb） of double-base propellant using isothermal and non-isothermal decomposition behaviours is presented. For double-base propellant composed of 56±1wt% of nitrocellulose （NC）, 27±0.5wt% of nitroglycerine （NG）, 8.15±0.15wt% of dinitrotoluene （DNT）, 2.5±0.1wt% of methyl centralite, 5.0±0.15wt% of catalyst and 1.0±0.1wt% of other, the values of r of 49.4 years at 40℃, of TSAOT of 151.35℃ and of Tb of 163.01℃ were obtained.

Flexible rotation of transverse optical field for 2D self-accelerating beams with a designated trajectory

Self-accelerating beams have the unusual ability to remain diffraction-free while undergo the transverse shift during the free-space propagation.We theoretically identify that the transverse optical field distribution of 2D self-accelerating beam is determined by the selection of the transverse Cartesian coordinates,when the caustic method is utilized for its trajectory design.Based on the coordinate-rotation method,we experimentally demonstrate a scheme to flexibly manipulate the rotation of transverse optical field for 2D self-accelerating beams under the condition of a designated trajectory.With this scheme,the transverse optical field can be rotated within a range of 90 degrees,especially when the trajectory of 2D self-accelerating beams needs to be maintained for free-space photonic interconnection.

Internal Gravity Waves Generated by a Local Thermal Source in an Irrotational Zonal－Vertical Plane：Numerical Analysis

The vertical and horizontal propagation of internal gravity waves forced by a local thermal source at the lowerboundary is examined using the irrotational two-dimensional model developed by Zhang et al. (1995).The sourcegenerates waves with the same absolute frequency 1/15 d-1 but different wavenumber.Internal gravity waves withwide spreading frequencies and wavenumbers appear due to wave-wave interactions. The foreced waves iW (westward-propagating with wavenumber 1)and iE (eastward-propagating with wavenumber 1),whose absolute phasespeeds are 31 m s-1,are predominant. Other forced waves with smaller phase speeds are relatively weaker.Thesewaves interact with the zonal mean flow,causing the flow to alternate with easterly and westerly with a 32-month period. The absolute maximum wind speeds of easterly and westerly are 35 m s-l which is larger than the largest phasespeed of forced waves. The forced waves iE and iW may accelerate easterly and westerly up to i 31 m s',respectively.The excessive accelerations are due to the self--acceleration of waves iE and iW or newly generated highfrequency waves iE and IW.The horizontal propagation of the waves are mainly affected by the forcing and wave--flow interactions whichlead to fast-slow variations of wave phase speed and amplitude.

Stoichiometric Imbalance-promoted Step-growth Polymerization Based on Self-accelerating Three-component Reaction

Aself-accelerating three-component reaction was developed using the secondary amines,CS_(2),and sym-dibenzo-1,5-cyclooctadiene-3,7-diyne(DIBOD)as reactants.In this three-component reaction,the secondary amine reacts with CS_(2) to form dithiocarbamate anion,which subsequently in-situ reacts with DIBOD behaving a self-accelerating reaction property.Specifically,the reaction of dithiocarbamate anion with the first alkyne of DIBOD activates the unreacted alkyne,which reacts with dithiocarbamate anion much faster than the original alkyne of DIBOD.Using the self-accelerating three-component reaction as polymerization reaction,a stoichiometric imbalance-promoted step-growth polymerization method was developed using the difunctional secondary amines,CS_(2),and DIBOD as monomer groups.This novel three-component polymerization can quickly produce high molecular weight dithiocarbamate-containing polymers under mild conditions using a slight molar excess of DIBOD to difunctional secondary amine monomer.Containing sulfur elements in the backbones,the resultant polymers hold high refractivity and may find potential applications in optical and optoelectronic fields.

Self-accelerated optical activity in free space induced by the Gouy phase

Optical activity(OA)is the rotation of the polarization orientation of the linearly polarized light as it travels through certain materials that are of mirror asymmetry,including gases or solutions of chiral molecules such as sugars and proteins,as well as metamaterials.The necessary condition for achieving OA is the birefringence of two circular polarizations in material.Here,we propose a new kind of self-accelerated OA in free space,based on the intrinsic Gouy phase induced mode birefringence of two kinds of quasi-non-diffracting beams.We provide a detailed insight into this kind of self-accelerated OA by analyzing angular parameters,including angular direction,velocity,acceleration,and even the polarization transformation trajectory.As the Gouy phase exists for any wave,this kind of self-accelerated OA can be implemented in other waves beyond optics,from acoustic and elastic waves to matter waves.

Polymer Synthesis Based on Self-Accelerating 1,3-Dipolar Cycloaddition Click Reactions

This review reports our recent work on developing polymer synthesis methods based on a self-accelerating double-strain-promoted 1,3-dipole-alkyne cycloaddition(DSPDAC)click reaction.In DSPDAC,the cycloaddition of 1,3-dipole with the first alkyne of sym-dibenzo-1,5-cyclooctadiene-3,7-diyne(DIBOD)activates the second unreacted alkyne,which reacts with 1,3-dipole much faster than the original alkyne of DIBOD.When using DIBOD and bis-dipole compounds as monomer pairs,the self-accelerating property of DSPDAC allows us to develop a stoichiometric imbalance-promoted step-growth polymerization method.It could produce polymers with ultrahigh molecular weight in the presence of excess DIBOD monomers.When using DIBOD to ring-close linear polymers with 1,3-dipole end groups,the self-accelerating property of DSPDAC facilitates us to develop a unique bimolecular ring-closure method.It could efficiently prepare pure cyclic polymers in the presence of excess DIBOD small linkers to linear polymer precursors.

Talbot effect in nonparaxial self- accelerating beams with electromagnetically induced transparency

In this study,we report on the fractional Talbot ffect of nonpar axial self-accelerating beams in a multilevel electromagnetically induced transparency(EIT)atomic configuration,which,to the best of our knowledge,is the first study on this subject.The Tallbot ffect originates from superposed eigenmodes of the Helmholtz equation and forms in the EIT window in the presence of both linear and cubic susceptibilities.The Talbot ffect can be realized by appropriately selecting the cofficients of the beam components.Our results indicate that the larger the radial difference between beam components,the stronger the interference between them,the smaller the Tallbot angle is.The results of this study can be useful when studying optical imaging.optical measurements,and optical computing.