Evaluation of Thermal Hazard of Composite Modified Double-base Propellant by Microcalorimetery Method

The thermal decomposition behavior of composite modified double-base（CMDB） propellant containing cyclotrimethylene trinitramine（RDX） was studied via a Calvet microcalorimeter at five different heating rates. The activation energy（E） and the pre-exponential factor（A） of two obvious exothermic processes were obtained by Kissinger＇s method and Ozawa＇s method. The entropy of activation（△S^≠）, the enthalpy of activation（△H^≠）, and the free energy of activation（△G^≠） of the first stage were calculated. To evaluate the thermal hazard of the RDX-CMDB propellant, the critical temperature of thermal explosion（Tb）, the self acceleration decomposition temperature（Tsgox）, the adiabatic decomposition temperature increment（ATad） and the time-to-explosion of adiabatic system（t） were presented as 145.3 ℃, 138.15 ℃, 1634 K and 583.71 s（n=0） and 586.28 s（n=1）, respectively.

Characterizations of the electrothermal parameters of a transition edge sensor microcalorimeter and its energy resolution

We developed a transition‐edge sensor microcalorimeter(μ‐calorimeter)using Mo/Au/Au thin films.We report the detector fabrication,the measurements of the electrothermal parameters and the noise characterizations of the transition‐edge sensor μ‐calorimeters.We estimated the energy resolution of theμ‐calorimeter using the measured noise spectrum and the calculated power‐to‐current responsivity.Using a ^(55)Fe radioactive X‐ray source,we characterized the detector responses to incident photons at various working points.The best instrumental energy resolution achieved was 4.13 eV@5.9 keV,which agrees qualitatively with the resolution of 4.01 eV estimated from the noise spectrum.

Development of superconducting microcalorimeters for the HUBS mission

Hot Universe Baryon Surveyor(HUBS)is a proposed space‐borne observatory for X‐ray astronomy.The primary scientific objectives of the mission are to fill a void in probing the ecosystem of galaxies and thus to advance our understanding of galaxy formation and evolution,which is of fundamental importance in cosmology.More specifically,HUBS aims at directly detecting soft X‐ray emission from diffuse gas of temperature exceeding 106 K,which is theoretically postulated to permeate the large structures in the cosmic web and also fill the extended halo of galaxies.However,although some indirect evidence exists,the presence of such hot gas has yet to be well established observationally,due to the lack of effective tools to probe it.In this paper,we describe the design of HUBS,focusing on its scientific payload,which employs superconducting technologies in the detector system,and particularly on progress in the development of superconducting microcalorimeters.

A titration microcalorimeter and the vesicle of mixed surfactants

A titration microcalorimeter with the sample cells of 1 mL and 3 mL volume was constructed by combining LKB-2107 ampule microcalorimeter with an improved Thermometric titration microcalorimeter. Its sensitivity and precision were tested with the baseline noise and stability, the measurement of energy equivalent, and the linear relation of electric energy and integral area as the function of voltage(V)-time (t). Its accuracy was demonstrated by measuring the dilution enthalpy of a concentrated sucrose solution and the micelle-forming enthalpy of sodium dodecyl sulfate (SDS) in aqueous solution respectively. At the same time, the enthalpy of interaction between SDS and didodecyldimethylammonium bromide (DDAB) was measured by using the titration microcalorimeter, and the phase behavior of SDS-DDAB aqueous mixture was discussed. The microcalorimetric results show that the enthalpy of interaction between SDS and DDAB micelles is -29.53 kJ/mol, the enthalpy of formation of 1:1 SDS-DDAB salt is -125.8 kJ/mol, the vesicle-forming enthalpy of SDS-DDAB is 41.23 kJ/mol, and the enthalpy of phase transition from vesicles to SDS rich micelle is 32.10 kJ/mol.

Thermokinetics of Liquid-Liquid Reaction of Dy(NO_3)_3 with Histidine

The thermokinetics of liquid liquid reaction of dysprosium nitrate with histidine were studied using a microcalorimeter. On the basis of experimental and calculated results, three thermodynamic parameters (the activation enthalpy, the activation entropy and the activation free energy), the rate constant, three kinetic parameters (the activation energy, the pre exponential constant and the reaction order) were obtained. On the basis of thermodynamics and kinetics, the formation reaction of the complex was discussed.

Thermochemistry of Ternary Complex Dy(Et_2dtc)_3(phen)

The ternary solid complex was synthesized with sodium diethyldithiocarbamate (NaEt_2dtc), 1,10-phenanthroline (phen) and low hydrated dysprosium chloride in absolute ethanol by improved method of reference. The title complex was identified as the general formula of Dy(Et_2dtc)_3(phen) by chemical and elemental analyses. IR spectrum of the complex shows that the Dy^(3+) coordinated with six sulfur atoms of three NaEt_2dtc and two nitrogen atoms of phen. It is assumed that the coordination number of Dy^(3+) is eight.The enthalpy change of liquid-phase reaction of formation, Δ_rH~θ_m(l), is determined as (-19.091±0.015) kJ·mol^(-1) at 298.15 K by a microcalorimeter, and the enthalpy change of the solid-phase reaction of formation, Δ_rH~θ_m(s), is calculated as (139.641±0.482) kJ·mol^(-1) on the basis of a thermochemical cycle. The thermodynamic of reaction of formation was studied by changing the temperature of liquid-phase reaction. The constant-volume combustion energy of the complex, Δ_cU, is determined as (-16730.21±9.25) kJ·mol^(-1) by a precise rotating-bomb calorimeter at 298.15 K. Its standard enthalpies of combustion, Δ_cH~θ_m, and standard enthalpies of formation, Δ_fH~θ_m, are calculated as (-16749.42±9.25) kJ·mol^(-1) and (-2019.68±10.19) kJ·mol^(-1), respectively.

Thermal behavior analysis of nickel/metal hydride battery during overcharging

To analyze the thermal behavior of the cylinder Ni/MH battery during overcharging,a two-dimensional thermal model is provided in this work.More reliable data is provided to create the precise thermal model.The amount of heat of the battery during overcharging at different currents was measured using quartz frequency microcalorimeter.To obtain the heat transfer coefficient of the battery during overcharging,the heat dissipation rate was fitted into linear functions and three different exponential functions from the temperature value measured by the microcalorimeter.The heat dissipation process after the linear stage was regared to accord with some mathematical differential expressions,which facilities understanding of the variation rule of heat dissipation rate during the transition stage and overcharging process.Theoretical values were used as heat generation rates in the heat transport equation.Using the measured data,the internal temperature profiles at the end of each stage during charging at 1C,3C and 5C were simulated using FEM.

Thermochemistry of the Ternary Complex Nd(Et_2dtc)_3(phen)

The ternary solid complex has been synthesized with sodium diethyldithiocarbamate (NaEt2dtc?3H2O), 1,10-phenanthroline (o-phen?H2O) and hydrated neodymium chloride in absolute ethanol. The title complex was identified as the general formula of Nd(Et2dtc)3(phen) by chemical and elemental analyses. IR spectrum of the complex showed that the Nd3+ coordinated with six sulfur atoms of three NaEt2dtc and two nitrogen atoms of o-phen. It was assumed that the coordination number of Nd3+ is eight.The enthalpy change of liquid-phase reaction of formation, ?rHm (l), was determined as (-12.274±0.050) kJ?mol-1 at 298.15 K by a microcalorimeter, the Θ enthalpy change of the solid-phase reaction of formation, ?rHm (s), was calculated as (149.069±0.314) kJ?mol-1 Θ on the basis of a thermochemical cycle. The thermodynamics of reaction of formation was studied by changing the temperature of liquid-phase reaction. The constant-volume combustion energy of the complex, ?cU , was deter- mined as (-18674.22±8.33) kJ?mol-1 by a precise rotating-bomb calorimeter at 298.15 K. Its standard enthalpy of combustion, ?cHm , and standard enthalpy of formation, ?fHm , were calculated as (-18693.43±8.33) kJ?mol-1 Θ Θ and (-47.03±9.17) kJ?mol-1, respectively.