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  • Author or Editor: Shu Liu x
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Abstract  

We present the distribution of astronomical papers published by Chinese authors in 1986–1990 across the various subfields of astronomy, the total number of papers produced by each observatory or university during the five years, and the ranking of the observatories by productivity. Our main data base includes 24 journals: 9 foreign ones published in English, 10 Chinese national ones, and 5 Chinese observatory publications. About 70 journals published by Chinese universities have also been consulted. This data base covers up to 90% of all astronomical papers published during this period.

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Abstract

In our previous research (Liu et al., J Anal Appl Pyrol 63:303–325, 2002), the pseudo bi-component separated-stage model (PBSM) was suggested for the kinetic analysis on the decomposition of lignocellulosic materials in air at relatively lower heating rates. As a continuing work, this paper is intended to investigate the applicability of PBSM at different heating rates by experimental analyses. Decomposition of oil tea wood has been studied by means of non-isothermal thermogravimetric analysis in air atmosphere at 10–25 K min−1 heating rates. A two-step parallel reaction kinetic model is used to optimize the kinetic parameters of these materials in air. Meanwhile, an improved PBSM is developed to describe the thermal degradation process of oil tea wood. Furthermore, a comparison between the kinetic results of parallel model and PBSM reveals realistic applicability of PBSM. It is concluded that the PBSM has relatively high accuracy for the first decomposition step in the lower temperature range, while fails to predict the thermal decomposition behavior in the char oxidative process which occurs in the higher temperature range.

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Abstract  

Many concerns over unsafe or unknown properties of multi-walled carbon nanotubes (MWNTs) have been raised. The thermal characteristics regarding stability would represent potential hazards during the production or utilization stage and could be determined by calorimetric tests for various thermokinetic parameters. Differential scanning calorimetry (DSC) was employed to evaluate the thermokinetic parameters for MWNTs at various compositions. Thermoanalytical curves showed that the average heat of decomposition (ΔH d) of the MWNTs samples in a manufacturing process was about 31,723 J g−1, by identifying them as an inherently hazardous material. In this study, significant thermal analysis appeared in the presence of sulfuric acid (H2SO4). From the DSC experiments, the purification process of MWNTs could induce an unexpected reaction in the condition of batch addition with reactants of H2SO4. The results can be applied for designing emergency relief system and emergency rescue strategies during a perturbed situation or accident.

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Abstract  

Due to the experimental errors, the chemical effect of minor reactions, and some physical effects of heat and mass transfer, there usually exists much noise in the mass loss data resulted from thermal decomposition experiments, and thus high quality smoothing algorithm plays an important role in obtaining reliable derivative thermogravimetric (DTG) curves required for differential kinetic analysis. In this paper three smoothing methods, i.e. Moving Average smoothing, Gaussian smoothing, and Vondrak smoothing, are investigated in detail for pre-treatment of biomass decomposition data to obtain the DTG curves, and the smoothing results are compared. It is concluded that by choosing reasonable smoothing parameters based on the spectrum analysis of the data, the Gaussian smoothing and Vondrak smoothing can be reliably used to obtain DTG curves. The kinetic parameters calculated from the original TG curves and smoothed DTG curves have excellent agreement, and thus the Gaussian and Vondrak smoothing algorithms can be used directly and accurately in kinetic analysis.

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Abstract

The thermokinetic parameters were investigated for cumene hydroperoxide (CHP), di-tert-butyl peroxide (DTBP), and tert-butyl peroxybenzoate (TBPB) by non-isothermal kinetic model and isothermal kinetic model by differential scanning calorimetry (DSC) and thermal activity monitor III (TAM III), respectively. The objective was to investigate the activation energy (E a) of CHP, DTBP, and TBPB applied non-isothermal well-known kinetic equation to evaluate the thermokinetic parameters by DSC. We employed TAM III to assess the thermokinetic parameters of three liquid organic peroxides, obtained thermal runaway data, and then used the Arrhenius plot to obtain the E a of liquid organic peroxides at various isothermal temperatures. In contrast, the results of non-isothermal kinetic algorithm and isothermal kinetic algorithm were acquired from a highly accurate procedure for receiving information on thermal decomposition characteristics and reaction hazard.

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Abstract  

Some results of tests on removing radium from liquid phase by adsorption on barytes are described. The paper demonstrates the mechanism for removal of radium, which is basically a chemical exchange between radium and barium ions on solid surface.

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Abstract  

Pooling lauroyl peroxide (LPO) with nitric acid, we used differential scanning calorimetry (DSC) to assess the thermokinetic parameters, such as exothermic onset temperature (T 0), heat of decomposition (ΔH d), frequency factor (A), and the other safety parameters. When LPO was contaminated with nitric acid (HNO3), we found the exploder 1-nitrododecane. Obvious products were sensitive and hazardous chemicals. Concentration reaching 1–12 N HNO3 emitted a large amount of heat. This study combined with curve-fitting method to elucidate its unsafe characteristics and thermally sensitive structure to help prevent runaway reactions, fires and explosions in the process environment. According to the findings and the concept of inherently safer design, LPO runaway reactions could be adequately prevented in the relevant plants.

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Abstract  

In this study, α-phase nucleating agent (NA) 1,3:2,4-bis(3,4-dimethylbenzylidene) sorbitol (DMDBS), β-phase rare earth NA (WBG), and their compound NAs were introduced into isotactic polypropylene (iPP) matrix, respectively. Crystallization kinetics and subsequent melting behavior of the nucleated iPPs were comparatively studied by differential scanning calorimetry (DSC) under both isothermal and nonisothermal conditions. For the isothermal crystallization process, it is found that the Avrami model successfully described the crystallization kinetics. The active energy of nonisothermal crystallization of iPP was determined by the Kissinger method and showed that the addition of nucleating agents increased the activation energy. Melting behavior and crystalline structure of the nucleated iPPs are dependent on the nature of NAs and crystallization conditions. Higher proportion of β-phase can be obtained at higher content of β-nucleating agent and lower crystallization temperature or lower cooling rate.

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