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  • Author or Editor: C.Y. Wang x
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Abstract  

We prove that the Eisenstein series E(z, s) have no real zeroes for s ∈ (0, 1) when the value of the imaginary part of z is in the range
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< Im z < 4.94. For very large and very small values of the imaginary part of z, E(z, s) have real zeros in (½, 1), i.e. GRH does not hold for the Eisenstein series. Using these properties, we prove that the Rankin-Selberg L-function attached with the Ramanujan τ-function has no real zeros in the critical strip, except at the central point s = ½.
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Abstract

Let denote the set {n∣2|n, ∀ p>2 with p−1|k}. We prove that when , almost all integers can be represented as the sum of a prime and a k-th power of prime for k≧3. Moreover, when , almost all integers n∊(X,X+H] can be represented as the sum of a prime and a k-th power of integer for k≧3.

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Abstract  

Thermal runaway reactions associated with exothermic behaviors of tert-butyl hydroperoxide (TBHP) solutions and TBHP reacting with alkaline contaminants were studied. A differential scanning calorimetry (DSC) was used to characterize these inherent behaviors of TBHP solutions with KOH, NaOH, LiOH and NH4OH. The exothermic peak in thermal curves of TBHP solutions with different alkali were detected by DSC thermal analysis. By thermal analysis, we compared various heats of decomposition of TBHP solutions with alkaline impurities, and determined the incompatible hazards of various TBHP solutions with alkaline contaminants. Comparing with TBHP in various diluents, the adiabatic runaway reaction via vent sizing package 2 (VSP2) indicated that aqueous TBHP intrinsically possesses the phenomena of thermal explosion with dramatic self-reactive rate and pressure rise under adiabatic conditions. Many commercial organic peroxides may have different hazard behaviors. Therefore, using thermal method to classify the hazards is an important subject.

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Abstract  

Analytical equations related adiabatic runaway reactions to programmed scanning thermal curves from differential scanning calorimetry (DSC) were proposed. Thermal or pressure hazards can be assessed from the adiabatic trajectories expressed in the analytical equations. These industrially energetic materials include polymerizable monomers, unstable organic peroxides and nitro-compounds. Various emergency relief behaviors, such as tempered vapor, gassy, and hybrid were re-evaluated for calculating vent sizing or mass flow rates from DSC thermal curves and the related physical properties.

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Abstract

Vent sizing package 2 (VSP2) was used to measure the thermal hazard and runaway characteristics of 18650 lithium-ion batteries, which were manufactured by Sanyo Electric Co., Ltd. Runaway reaction behaviors of these batteries were obtained: 50% state of charge (SOC), and 100% SOC. The tests evaluated the thermal hazard characteristics, such as initial exothermic temperature (T 0), self-heating rate (dT dt −1), pressure-rise rate (dP dt −1), pressure temperature profiles, maximum temperature, and pressure which were observed by adiabatic calorimetric methodology via VSP2 using customized test cells. The safety assessment of lithium-ion cells proved to be an important subject. The maximum self-heating rate (dT dt −1)max and the largest pressure-rise rate (dP dt −1)max of Sanyo 18650 lithium-ion battery of 100% SOC were measured to be 37,468.8 °C min−1 and 10,845.6 psi min−1, respectively, and the maximum temperature was 733.1 °C. Therefore, a runaway reaction is extremely serious when a lithium-ion battery is exothermic at 100% SOC. This result also demonstrated that the thermal VSP2 is an alternative method of thermal hazard assessment for battery safety research. Finally, self-reactive ratings on thermal hazards of 18650 lithium-ion batteries were studied and elucidated to a deeper extent.

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Abstract  

A TiO2/monazite photocatalyst was prepared by embedding TiO2 nanoparticles into a monazite substrate surface. TiCl4 hydrolysis/citric acid chelating procedure under acidic conditions were used to synthesize the nanophase TiO2 particles. The anatase TiO2/monazite photocatalyst surface area, morphology, crystalline and elemental concentrations were characterized using Brunauer-Emmett-Teller (BET) method, scanning electron microscopy (SEM), X-ray diffraction (XRD), and inductively coupled plasma-atomic emission spectrometry (ICP-AES). Monazite contains a large amount of Ce-, La-, Nd- and Th-PO4 compounds; it has been known as a natural mineral material with minor radioactivity. TiO2-CeO2 composite is a kind of radiation sensitive photocatalyst in which the radiations of thorium nuclides give energy to trigger TiO2 and cerium ions which play an energy absorber with charge separator. The result showed that methylene blue and phenol were spontaneously photocatalytic decomposed by TiO2/monazite composite even in a dark environment. A synergistic effect was also examined with applied exterior UV or 60Co irradiation. A hybrid mechanism is proposed; according by the radioluminescence (RL) from excited Ce ion by γ-radiation soliciting CeO2/TiO2 heterojunction (HJ). This seems to be a possible mechanism to explain this self-activated photo-catalytic behavior.

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Abstract  

Two methods, e.g. initial rate method and thermokinetic reduced extent method were presented for studies on non-competitive inhibition. Arginase-catalyzed the hydrolysis of L-arginine toL-ornithine and urea and the inhibition of this reaction by sodium fluoride were studied in the absence and presence of exogenous of Mn2+at 37C in 40 mM sodium barbiturate-hydrochloric acid buffer solution (pH 7.4). Both methods were successively used to determine the values of K1. The advances and disadvantages of each method were compared in this paper. Exogenous Mn2+ could result in more sensitivity of arginase to F-1. Since the inhibition of arginase by F-1 depends on the pH values of the reaction system and behave as a non-competitive inhibition, it probably due to its small volume and high electronic density allow it access to the activity site of the enzyme and replaces of -OH2 (or -OH) as the bridge ligand with Mn(II, II) cluster. However, further studies are necessary to determine the modes of interaction of F-1 with bovine liver arginase.

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Abstract  

For the enhancement of thermal stability of poly(p-dioxanone) (PPDO), the isocyanate end-capping reagent was prepared by treatment of toluene-2,4-diisocyanate with an equivalent of 1-hexyl alcohol. The end-capping reagent and the end-capping PPDO with an inherent viscosity of 0.26 dL g−1 were characterized by FTIR and 1H-NMR. Thermal stability of the end-capping PPDO with an inherent viscosity of 0.92 dL g−1 was investigated isothermally and non-isothermally under air atmosphere using thermogravimetry. It has been shown that the addition of the prepared isocyanate can enhance significantly the thermal stability of PPDO. The activation energies for non-isothermal degradation estimated by Kissinger method and Friedman method are 91, 81 kJ mol−1 for as-prepared PPDO, and 160, 149 kJ mol−1 for the end-capping PPDO, respectively. The activation energy increases by about 70 kJ mol−1 through the end-capping.

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Abstract  

The effect of excipients on the secondary structure of lyophilized proteins was studied through second-derivative Fourier transform infrared (FTIR) spectroscopic analysis. The glass transition temperature (T g), denaturation temperature (T d) and moisture content were determined by differential scanning calorimetry (DSC) and thermogravimetry (TG). T g, T d and the preservation of protein secondary structure were found to be dependent upon the type and amount of the excipient included in the formulation. Meanwhile, the lyophilized proteins easily adsorbed amounts of moisture during storage to reduce their T gs and stability.

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Abstract  

N,N,N',N'-Tetrabutyladipicamide (TBAA) was used for the extraction of nitric acid and uranyl(II) ion from nitric acid media into toluene. The effects of nitric acid, uranyl(II) ion, and extractant concentration, temperature and back extraction on the distribution coefficient of uranyl(II) ion have been studied. The main adduct of TBAA and HNO3 is TBAA·HNO3 in 1.0 mol/l nitric acid solution. The 1:2:2 complex of uranyl(II) ion, nitrate ion and TBAA as extracted species is further confirmed by IR spectra of the extraction of uranyl(II) ion with TBAA. The values of the thermodynamic parameters have also been calculated.

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