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Abstract  

Some atomic decomposition theorems are proved in vector-valued weak martingale Hardy spaces w pΣα(X), w p Q α(X) and wD α(X). As applications of atomic decompositions, a sufficient condition for sublinear operators defined on some vector-valued weak martingale Hardy spaces to be bounded is given. In particular, some weak versions of martingale inequalities for the operators f*, S (p)(f) and σ(p)(f) are obtained.

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High levels of peptides can accumulate in tissues of legumes during germination. In this study, effects of germination conditions (pH, temperature, and time) on protease activity and peptides accumulation in soybean were investigated. The desirable level scope of parameters was used to further optimise germination conditions for peptides accumulation using response surface methodology. Results showed that protease activity and peptides yield were significantly influenced by pH, temperature, and time (P<0.05). The optimal pH, temperature, and time for protease activity were 5, 25 °C, and 6 days, respectively. Meanwhile, the optimal pH, temperature, and time for peptides content were 5, 30 °C, and 5 days, respectively. Box–Behnken design indicated the following optimal germination conditions: pH 4.8, temperature 29 °C, and time 5 days. Under these conditions, the highest peptides content (14.46 mg g–1 FW) in germinated soybean was obtained. The present study indicates that germinated soybean can be a valuable component of peptides-enriched foods.

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Abstract  

Organic peroxides (OPs) are very susceptible to thermal sources, chemical pollutants or even mechanical shock. Over the years, they have caused many serious explosions. Cumene hydroperoxide (CHP) is widely employed to produce phenol and dicumyl peroxide (DCPO) in the manufacturing process. Differential scanning calorimetry (DSC) and thermal activity monitor (TAM) were employed to determine the potential thermal hazards and thermokinetic parameters (such as exothermic onset temperature (T 0), maximum temperature (T max), and enthalpy (ΔH)) of CHP mixed with sodium hydroxide (NaOH) and sulfuric acid (H2SO4). High performance liquid chromatography (HPLC) was used to analyze the concentration vs. time of CHP.When CHP is mixed with NaOH, the T 0 is induced earlier and reactions become more intricate than the pure CHP solution. CHP added to NaOH or H2SO4 is more dangerous than pure CHP alone. Depending on the operating conditions, NaOH and H2SO4 are the incompatible chemicals for CHP.

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Abstract  

In petrochemistry, dicumyl peroxide (DCPO) is used in various resins for improving physical properties, which was produced by cumene hydroperoxide (CHP) with oxidization reaction, redox reaction, and dehydration reaction. The reactant, CHP, is a typical organic hydroperoxide and has been intrinsically unstable and reactive due to its bivalent -O-O- structure which can be broken readily with bond-dissociation energy. This sequence on sensitive study aimed at the thermal hazard evaluation for the reactive and incompatible characteristics of CHP mixed with various inorganic alkaline solutions. Differential scanning calorimetry (DSC) and vent sizing package 2 (VSP2) were used to analyze the thermal hazards and runaway reaction of redox system, such as decomposition of CHP in cumene solution and CHP react with inorganic alkaline solutions, exothermic onset temperature, peak power, heat of decomposition of dynamic scanning tests, adiabatic self-heating rate, pressure rise rate, maximum temperature, maximum pressure of reaction system, etc. The results of the tests have proven helpful in establishing safe handling, storage, transportation, and disposal guidelines.

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Summary

A new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous determination of glycyrrhizin, formononetin, glycyrrhetinic acid, liquiritin, isoliquiritigenin, and licochalcone A in licorice. An Eclipse Plus C18 column (I.D. 4.6 × 100 mm, 3.5 μm particle size; Agilent) was used in the analysis. Electrospray ionization (ESI)-tandem interface in the negative mode was performed, and multiple reaction monitoring (MRM) was employed with the precursor multiple reaction monitoring production combination for the determination of six analytes. The average recoveries ranged from 98.30% to 100.13% with relative standard deviations (RSDs) ≤ 1.95%, and limits of detection (LODs) ranged from 2.1 to 3.6 pg. The applicability of this analytical approach was confirmed by the successful analysis of six samples. The results indicated that the established method was validated, sensitive, and reliable for the determination of six analytes in licorice.

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Abstract  

Cumene hydroperoxide (CHP) is classified as a flammable hazard in NFPA 43B. Fires or explosions induced by thermal hazards ascribed to the unstable hydroperoxyl or peroxyl groups are often reported. This sequence studies is aimed at the decomposition phenomena associated with the reactive and incompatible characteristics of CHP mixed with alkaline solutions. Various alkalines were used for comparing the relative impact of bases and effects on concentrations. Exothermic onset temperatures and heats of decomposition of these incompatible mixtures were performed by differential scanning calorimetry (DSC). Comparisons of exothermic onset temperature, peak power, heat of decomposition, etc., were assessed to verify the severity of incompatible hazards in these systems. When mixed with a small amount of the hydroxides (in the production or storage of CHP), CHP will be more labile or unstable because of lower exothermic temperature. In addition, to elucidate the final products and propose mechanisms of the reaction of CHP mixed with alkaline solution, the analytical results were carried out by GC/MS and IR. The exhibited reactivity was complicated and significantly affected by the alkaline solutions. The reaction schemes have been proposed in this study. These results are especially important in process safety design for producing CHP and its related compounds, such as phenol, α-cumyl alcohol (CA), acetophenone (AP), and dicumyl peroxide (DCPO).

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Abstract  

A differential scanning calorimetry (DSC) and thermal activity monitor (TAM) were used to study the thermo-kinetic parameters for dicumyl peroxide (DCPO) at various concentrations. The potential thermal hazards of intermediates and end products whose concentrations were at approximately 50, 70, 94 and 99.3 mass%, respectively, in the process of operating DCPO were investigated. Thermoanalytical curves indicate that the average heat of decomposition of various DCPO samples in a manufacturing process was 762 to 1200 J g -1 which made it an inherently hazardous material. In the incompatibilities study, significant thermal hazards appeared in the presence of H2SO4. From the TAM experiments, the synthetic process of DCPO could result in an unexpected reaction in the condition of batch addition with reactants and H2SO4.

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Abstract  

Thermogravimetry (TG) was employed to study the thermal degradation kinetics of poly(etherketone/sulfone)ethylimide (PEK-IE and PES-IE). The corresponding decomposition activation energies and reaction orders were obtained and the comparison was made with their parent polymerspoly(ether-ketone/sulfone) with Cardo group (PEK-C and PES-C). The results show that the degradation activation energies of PEK-IE and PES-IE were lower than that of PEK-C and PES-C; and two stages of the degradation process were found for all the four polymers. For PEK-IE and PES-IE, the activation energies in the first decomposition stage are much lower than that in the second stage and the two stages can be taken as slow induction and fast degradation, whereas for PEK-C and PES-C the activation energies in the first decomposition stage are larger than that in the second stage, and the two stages can both be taken as two fast degradation stages. The decomposition mechanism of the two stages was also speculated.

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