Thermodynamic Study on Antibacterial Effect of Different Extracts from Radix Isatis

Objective： To study and analyze the antibacterial effects of different extracts from Radix Isatis. Methods： Staphylococcus aureus was used as the studied object in the experiment. Antibacterial effects of extracts from Radix Isatis were observed by thermocalrimetry on Staphylococcus aureus, together with common pharmacological experiments. Results： The total extract, ethyl acetate （EtOAc） extract, n-butylalcohol （nBuOH） extract, chloroform （CHCl3） extract and petroleum （P. E.） extract had antiviral effects to some extent while the residue after extracting had no antibacterial activity. The potency of antiviral activity among them was as follows： nBuOH extract 〉 EtOAc extract 〉 CHCl3 extract〉 total extract 〉P. E. extract. Conclusion： The antibacteriall effects of Radix Isatis were not limited to any active portion, showing that Radix Isatis exerts its antibacterial effects by cooperation of different active fractions in varied ways.

Thermodynamic Effects on Particle Movement:Wind Tunnel Simulation Results

Sand/dust storms are some of the main hazards in arid and semi-arid zones. These storms also influence global environmental changes. By field observations, empirical statistics, and numerical simulations, pioneer researchers on these natural events have concluded the existence of a positive relationship between thermodynamic effects and sand/dust storms. Thermodynamic effects induce an unsteady stratified atmosphere to influence the process of these storms. However, studies on the relationship of thermodynamic effects with particles (i.e., sand and dust) are limited. In this article, wind tunnel with heating was used to simulate the quantitative relationship between thermodynamic effects and particle movement on different surfaces. Compared with the cold state, the threshold wind velocity of particles is found to be significantly decrease under the hot state. The largest decrease percentage exceedes 9% on fine and coarse sand surfaces. The wind velocity also has a three-power function in the sand transport rate under the hot state with increased sand transport. Thermodynamic effects are stronger on loose surfaces and fine particles, but weaker on compacted surfaces and coarse particles.

Effective first law of thermodynamics of black holes with two horizons

For a black hole with two horizons, the effective entropy is assumed to be a linear combination of the two entropies of the outer and inner horizons. In terms of the effective thermodynamic quantities the effective Bekenstein-Smarr formula and the effective first law of thermodynamics are derived.

Pressure Effects on Thermodynamics of Phase Behavior in Polystyrene/Methylcyclohexane Solutions

The calculations presented in this paper are based on the Sanchez-Lacombe（SL）lattice fluid theory.The interaction energy parameter,g12/k,required in this approach was obtained by fitting the cloud points of polystyrene（PS）/methylcyclohexane（MCH）polymer solutions under pressure.The SL lattice fluid theory was used to calculate the spinodals,the binodals,and the Flory-Huggins（FH）interaction parameter of the solutions.The calculated results show that the SL lattice fluid theory can describe the dependences of thermodynamics of PS/MCH solutions on temperature and pressure very well.However,the calculated enthalpy and the excess volume changes indicate that the Clausius-Clapeyron equation cannot be suitable to describe pressure effect on PS/MCH solutions.Further analysis on the thermodynamics of this system under pressure shows that the role of entropy is more important than the excess volume in the present case.

Substituent Effect on Infrared Spectra and Thermodynamic Properties of Polynitroamino Substituted Cyclopentane and Cyclohexane

Density functional theory method was employed to study the effect of the nitroamino group as a substituent in cyclopentane and cyclohexane, which usually construct polycyclic or caged nitramines. Based on the optimized molecular structures of two groups of monocyclic nitramines at the B3LYP/6-31G^＊＊ level, the infrared （IR） spectra were obtained and assigned by harmonic vibrational analysis. The calculated results agree reasonably with the available experimental data. According to the principles of statistic thermodynamics, thermodynamic properties were derived from the IR spectra, which were linearly correlated with the number of nitroamino groups as well as the temperature. The contributions of nitroamino groups to thermodynamic properties are in accord with the group additivity.

Magnetic Effects in the Thermodynamics of Information

The authors have shown that the process data can be modeled on the basis of chemical thermodynamics. The authors offer general information of the equation in the presence of a magnetic field. As a result, studies have shown that the magnetic effects strongly influence the thermodynamics of information.

Magnetic Effects in the Thermodynamics of the Process of Thinking

The authors have shown that the process of information and thinking can be modeled on the basis of chemical thermodynamics. The authors offer general equations to calculate the thinking of the work of judgment the L and of entropy solutions G in the presence of a magnetic field. As a result, studies have shown that the magnetic effects strongly influence the thermodynamics of the process of thinking.

Elasticity and Thermodynamic Properties of EuS Related to Phase Transition

First-principles calculations of the crystal structures, phase transition, and elastic properties of EuS have been carried out with the plane-wave pseudopotential density functional theory method. The calculated values are in very good agreement with experimental data as well as some of the existing model calculations. The dependence of the elastic constants, the aggregate elastic modulus, and the elastic anisotropy on pressure have been investigated. Moreover, the variation of the Poisson＇s ratio, Debye temperature, and the compressional and shear elastic wave velocities with pressure have been investigated for the first time. Through the quasi-harmonic Debye model, the thermal expansions, heat capacities, Grneisen parameters and Debye temperatures dependence on the temperature and pressure are obtained in the pressure range from 0 GPa to 60 GPa and temperature range from 0 K to 800 K.

Relativistic thermodynamic properties of a weakly interacting Fermi gas in a weak magnetic field

This paper derives the analytical expression of free energy for a weakly interacting Fermi gas in a weak magnetic field, by using the methods of quantum statistics as well as considering the relativistic effect. Based on the derived expression, the thermodynamic properties of the system at both high and low temperatures are given and the relativistic effect on the properties of the system is discussed. It shows that, in comparison with a nonrelativistic situation, the relativistic effect changes the influence of temperature on the thermodynamic properties of the system at high temperatures, and changes the influence of particle-number density on them at extremely low temperature. But the relativistic effect does not change the influence of the magnetic field and inter-particle interactions on the thermodynamic properties of the system at both high and extremely low temperatures.

Thermodynamic study of adsorption of phenolic compounds onto Amberlite XAD-4 polymeric adsorbents and its acetylized derivative MX-4

Adsorption equilibrium isotherms of phenolic compounds, phenol, p cresol, p chlorophenol and p nitrophenol, from aqueous solutions by Amberlite XAD 4 polymeric adsorbent and its acetylized derivative MX 4 within temperature range of 283 323K were obtained and fitted to the Freundlich isotherms. The capacities of equilibrium adsorption for all four phenolic compounds from their aqueous solutions increased around 20% on the acetylized resin, which may be contributed to the specific surface area and the partial polarity on the network. Estimations of the isosteric enthalpy, free energy, and entropy for the adsorption process were reported.

THERMODYNAMIC STUDY OF ADSORPTION OF PHENOLIC COMPOUNDS FROM AQUEOUS SOLUTION BY A WATER-COMPATIBLE HYPERCROSSLINKED POLYMERIC ADSORBENT

Equilibrium data for the adsorption of phenolic compounds, i.e., phenol, p-cresol, p-chlorophenol and p- nitrophenol from aqueous solutions by a water-compatible hypercrosslinked polymeric adsorbent (NJ-8) within temperature range of 283-323 K were obtained and correlated with a Freundlich-type of isotherm equation, so that equilibrium constants KF and n were obtained. The capacities of equilibrium adsorption for all the four phenolic compounds on the NJ-8 from aqueous solutions are around 2 times as high as those of Amberlite XAD-4, which may be attributed to the unusual micropore structure and the partial polarity on the network. The values of the enthalpy (always negative) are indicative of an exothermic process, which manifests the adsorption of all the four phenolic compounds on the two polymeric adsorbents to be a process of physical adsorption. The negative values of free energy change show that the solute is more concentrated on the adsorbent than in the bulk solution. The absolute free energy values of adsorption for NJ-8 are always higher than those for Amberlite XAD-4, which indicates that phenolic compounds are preferentially adsorbed on NJ-8. The negative values of the adsorption entropy are consistent with the restricted mobilities of adsorbed molecules of phenolic compounds as compared with the molecules in solution. The adsorption entropy values of phenolic compounds for NJ-8 are lower than those for Amberlite XAD-4, which means the micropores of NJ-8 require more orderly arranged adsorbate.

Process parameters influence on zone refining and thermodynamics analysis of 1,2-diphenylethane

Effective distribution coefficients of 9 impurities in 1,2-diphenylethane have been calculated by directional crystallization under different ambient frozen temperature.The effect of varied zone size,temperature difference between the melt and ambient frozen environment,number of zone on purity of 1,2-diphenylethane have been also investigated during the process of zone refining.The results indicate that the product purity in the intermediate purified region with varied zone size is higher 0.04%–0.2%than that with constant zone size.The product purity increases with temperature difference between the melt and ambient frozen environment.The appropriate temperature difference is adopted 50°C.The product purity in the intermediate region of sample bar with 2 molten zones is higher 0.05%–0.43%than that with 1 molten zone.In addition,the change of enthalpy and entropy between impurities and 1,2-diphenylethane have been determined.

Thermodynamic properties and phase stability of nanocrystalline metals

The fundamental thermodynamic functions of enthalpy, entropy, and Gibbs free energy, as functions of the excess free volume at interfaces, temperature, and grain size, have been derived for single-phase metal nanocrystals. The model was applied to predict the thermal features of nano-grain boundaries and the characteristics of phase transformation in nanocrystalline metals, such as the transformation temperature and the critical grain size for phase transformation at a given temperature. The model predictions have been verified by experimental studies on the β-Co ←→α-Co phase transformation in nanocrystalline Co prepared by ball milling.

Synthesis of Dimethyl Ether from CO Hydrogenation: a Thermodynamic Analysis of the Influence of Water Gas Shift Reaction

Three reactions involved in dimethyl ether (DME) synthesis from COhydrogenation: methanol synthesis reaction (MSR), methanol dehydration reaction (MDR) and water gasshift reaction (WGSR) are studied by thermodynamic calculation. For demonstrating this process indetail, three models, MSR, MSR+MDR, MSR+MDR+WGSR, are used. Their basic characteristics can beobtained by varying widely the ratios of H_2 to CO in the feed (no CO_2). Through thermodynamicanalysis a chemical synergic effect obviously exists in the second and third models. By comparisonbetween two models it is found that WGSR plays a special role in dimethyl ether synthesis. It ispossible for the two models to shift one to the other by regulating CO_2 concentration in feed. ForModel 2, the selectivity for DME in oxygenates (DME+methanol) does not change with the ratio of H_2to CO.

Analytical thermodynamical properties of a two-dimensional electron gas in a magnetic field

Analytical expressions for the thermodynamical properties of a two-dimensional electron gas in a perpendicular mag- netic field are derived. This is accomplished by first deriving the general expression for the thermodynamical potential, and then employing this result to obtain the corresponding expression for the two-dimensional gas. The chemical potential and magnetization are studied as a function of temperature and magnetic field, and shown to be in agreement with prior work. It is also shown that the results are close to those obtained by assuming a Gaussian density of states for the Landau levels.

Non-equilibrium thermodynamic analysis of coupled heat and moisture transfer across a membrane

Non-equilibrium thermodynamics theory is used to analyze the transmembrane heat and moisture transfer process,which can be observed in a membrane-type total heat exchanger(THX).A theoretical model is developed to simulate the coupled heat and mass transfer across a membrane,total coupling equations and the expressions for the four characteristic parameters including the heat transfer coefficient,molardriven heat transfer coefficient,thermal-driven mass transfer coefficient,and mass transfer coefficient are derived and provided,with the Onsager’s reciprocal relation being confirmed to verify the rationality of the model.Calculations are conducted to investigate the effects of the membrane property and air state on the coupling transport process.The results show that the four characteristic parameters directly affect the transmembrane heat and mass fluxes:the heat and mass transfer coefficients are both positive,meaning that the temperature difference has a positive contribution to the heat transfer and the humidity ratio difference has a positive contribution to the mass transfer.The molar-driven heat transfer and thermal-driven mass transfer coefficients are both negative,implying that the humidity ratio difference acts to reduce the heat transfer and the temperature difference works to diminish the mass transfer.The mass transfer affects the heat transfer by 1%–2%while the heat transfer influences the mass transfer by7%–14%.The entropy generation caused by the temperature difference-induced heat transfer is much larger than that by the humidity difference-induced mass transfer.

Using Quantum Statistics to Win at Thermodynamics, and Cheating in Vegas

Gambling is a useful analog to thermodynamics. When all players use the same dice, loaded or not, on the average no one wins. In thermodynamic terms, when the system is homogeneous—an assumption made by Boltzmann in his H-Theorem—entropy never decreases. To reliably win, one must cheat, for example, use a loaded dice when everyone else uses a fair dice;in thermodynamics, one must use a heterogeneous statistical strategy. This can be implemented by combining within a single system, different statistics such as Maxwell-Boltzmann’s, Fermi-Dirac’s and Bose-Einstein’s. Heterogeneous statistical systems fall outside of Boltzmann’s assumption and therefore can bypass the second law. The Maxwell-Boltzmann statistics, the equivalent of an unbiased fair dice, requires a gas column to be isothermal. The Fermi-Dirac and Bose-Einstein statistics, the equivalent of a loaded biased dice, can generate spontaneous temperature gradients when a field is present. For example, a thermoelectric junction can produce a spontaneous temperature gradient, an experimentally documented phenomenon. A magnetic field parallel to, and an electric field perpendicular to a surface produce a spontaneous current along the surface, perpendicular to both fields (Reciprocal Hall Effect). Experimental data collected by several independent researchers is cited to support the theory.

Computation of Energy, Intensity and Thermodynamic Parameters for the Interaction of Ln(III) with Nucleic Acid: Analysis of Structural Conformations, Chemical Kinetics and Thermodynamic Behaviour through 4f-4f Transition Spectra as Probe

Nucleosides and Nucleotides are polydentate ligands, offering potential binding sites for metal ions. Energy interaction parameters: Slater Condon Fk (cm-1), Spin Orbit interaction ξ4f? (cm-1), Nephelauxetic Ratio (β), Bonding (b1/2) and Covalency (δ) parameter for the interaction of Pr(III) with Nucleoside and Nucleotide are evaluated to study the mode of binding of the Nucleic Acid Components (Guanosine and Guanosine Triphosphate) with Pr(III). Further Intensity Parameters like Oscillation Strength and Judd Ofelt Parameter (T2, T4, T6) have been evaluated to investigate degree of inner or outer sphere co-ordination of Pr(III) with Nucliec Acid ligands. Comperative Absorption Spectra in different solvents substantiate the informations, gathered from the evaluated values of both energy interaction and intensity parameters. Further evaluation of Thermodynamic parameters (ΔG, ΔH and ΔS) through Kinetic studies enable to provide the detailed information about the reaction pathways and thermodynamic behavour of the complexation process of neucleosides and nucleotides with Pr(III) and Ca2+.

纳米材料杨氏模量的尺度依赖性

【目的】纳米材料杨氏模量与其对应的大块材料的杨氏模量完全不同,并且具有明显的尺度依赖性,然而纳米材料杨氏模量随尺度的变化却是多样且复杂的。一些金属纳米材料杨氏模量随着尺度减小而增大,并高于块体杨氏模量值;而一些半导体纳米材料的杨氏模量却随尺度的减小而降低,且低于块体杨氏模量值。这种相反的变化趋势的原因却并不清楚。【方法】基于纳米热力学理论,以纳米材料结合能为基础,从原子势函数与材料杨氏模量的内在关系出发,引入反映材料原子键本质的参数,详细推导了纳米材料杨氏模量定量解析过程,阐述了金属、非金属等纳米材料杨氏模量值和其随尺度的变化规律;揭示了纳米材料表面模量、内部模量对体系杨氏模量的贡献,并利用材料参数阐明纳米材料杨氏模量与尺度、原子键的物理关系。【结果】所构建的理论解析模型对零维纳米颗粒、一维纳米线和二维纳米薄膜的杨氏模量都进行了成功的预测。