试论巴西马瑙斯自由贸易区开发经验及其对我国开放开发的启示

试论巴西马瑙斯自由贸易区开发经验及其对我国开放开发的启示祁春节巴西地域辽阔，各地区经济发展极不平衡，为了开发北部落后地区，实现国家经济社会一体化发展战略，巴西政府对该地区采取了以点带面的发展战略。在深居内陆的西亚马孙河沿岸城市马瑙斯设立自由贸易区，将...

高温超导体RBa_2Cu_3O_y超导转变热力学

研究了稀土氧化物高温超导体ＲＢａ_２Ｃｕ_３Ｏ_ｙ（Ｒ：一般为稀土元素）超导转变的相变性质，认为在没有外界磁场作用时超导转变为二级相变，有外界磁场作用时为一级相变。推导出超导体ＲＢａ_２Ｃｕ_３Ｏ_ｙ在超导转变时体系的Ｇｉｂｂｓ自由能关系式。

A theoretical study of electrocatalytic ammonia synthesis on single metal atom/MXene

Electrocatalytic ammonia synthesis under mild conditions is an attractive and challenging process in the earth’s nitrogen cycle,which requires efficient and stable catalysts to reduce the overpotential.The N2 activation and reduction overpotential of different Ti3C2O2-supported transition metal(TM)(Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,Mo,Ru,Rh,Pd,Ag,Cd,and Au)single-atom catalysts have been analyzed in terms of the Gibbs free energies calculated using the density functional theory(DFT).The end-on N2 adsorption was more energetically favorable,and the negative free energies represented good N2 activation performance,especially in the presence Fe/Ti3C2O2(﹣0.75 eV).The overpotentials of Fe/Ti3C2O2,Co/Ti3C2O2,Ru/Ti3C2O2,and Rh/Ti3C2O2 were 0.92,0.89,1.16,and 0.84 eV,respectively.The potential required for ammonia synthesis was different for different TMs and ranged from 0.68 to 2.33 eV.Two possible potential-limiting steps may be involved in the process:(i)hydrogenation of N2 to*NNH and(ii)hydrogenation of*NH2 to ammonia.These catalysts can change the reaction pathway and avoid the traditional N–N bond-breaking barrier.It also simplifies the understanding of the relationship between the Gibbs free energy and overpotential,which is a significant factor in the rational designing and large-scale screening of catalysts for the electrocatalytic ammonia synthesis.

Computational screening of O‐functional MXenes for electrocatalytic ammonia synthesis

The nitrogen reduction reaction(NRR)using new and efficient electrocatalysts is a promising al‐ternative to the traditional Haber‐Bosch process.Nevertheless,it remains a challenge to design efficient catalysts with improved catalytic performance.Herein,various O‐functional MXenes were investigated as NRR catalysts by a combination of density functional theory calculations and least absolute shrinkage and selection operator(LASSO)regression.Nb_(3)C_(2)O_(X) has been regarded as a promising catalyst for the NRR because of its stability,activity,and selectivity.The poten‐tial‐determining step is*NH_(2) hydrogenation to*NH3 with a limiting potential of-0.45 V.Further‐more,via LASSO regression,the descriptors and equations fitting the relationship between the properties of O‐functional MXenes and NRR activity have been proposed.This work not only pro‐vides a rational design strategy for catalysts but also provides machine learning data for further investigation.

Treatment of Sebacic Acid Industrial Wastewater by Extraction Process Using Castor Oil Acid as Extractant

Wastewater containing high concentrations of phenol and sodium sulfate is generated in sebacic acid （SA） industry. Castor oil acid, a raw material for producing SA, can be used to extract phenol from wastewater in order to reduce the amount of phenol used in the process and discharge of phenol. The results show that the extrac- tion mechanism is that hydroxyl group of phenol is linked to carboxyl group of castor oil acid by hydrogen bond. The extraction process approaches equilibrium in 30 min. Extraction ratio increases with the increase of sodium sulfate and castor oil acid, and decreases as phenol increases. When the oil-water ratio is 1 ： 3, the optimal distribu- tion coefficient of 40 is obtained. Phenol saturation concentration in castor oil acid is 1.03 mol.L-1 after extraction for 4 times. The equilibrium constant （Kex） at 25℃ is 8.41 and the endothermic enthalpy （AH） is 1.513 kJ.mo1-1. The Gibbs free energy （AG） is -5.277 kJ. tool-1 and the value of AS is calculated to be 22.3 J. mo1-1. K-1.

Thermodynamic approach to synthesis of silver nanocrystalline by mechanical milling silver oxide

Thermodynamic analysis of the possibility of silver nanocrystalline preparation by high energy milling silver oxide was investigated. The molar Gibbs free energy function of mechanically activated samples was calculated from the structural defects such as amorphization, dislocation and surface energy. According to the molar Gibbs free energy function, the equilibrium temperature of mechanical reduction of silver oxide milled for 21 h was estimated at about 304 K. Consequently, at this temperature silver oxide cannot be stable and will transform to silver during the milling.

A Surface Tension Model for Liquid Mixtures Based on NRTL Equation

A new equation for predicting surface tension is proposed based on the thermodynamic definition of surface tension and the expression of the Gibbs free energy of the system. Using the NRTL equation to represent the excess Gibbs free energy, a two-parameter surface tension equation is derived. The feasibility of the new equation has been tested in terms of 124 binary and 16 multicomponent systems(13-ternary and 3-quaternary) with absolute relative deviations of 0.59% and 1.55% respectively. This model is also predictive for the temperature dependence of surface tension of liquid mixtures. It is shown that, with good accuracy, this equation is simple and reliable for practical use.

Equilibrium, thermodynamic, and kinetic of Cr(VI) adsorption using a modified and unmodified bentonite clay

The capacities of natural and modified Brazilian bentonite samples as adsorbents to remove hexavalent metal chromium were investigated under several conditions in batch and column methods. The raw material, Ca-bentonite, was modified by anchorament of 3-aminopropyltrietoxisilane （APS） and 3,2- aminoethylaminopropyltrimetoxisilane （AEAPS） in the surface of bentonite sample： This type of new occurrence of bentonite is suitable as a raw material for adsorption process. Adsorption behavior of three bentonite types was strongly depending on pH of adsorbate solution, contact time adsorbent/adsorbate, and initial concentration of Cr（VI）. The results were confirmed by column method and reveals that the adsorption process of materials accorded by the Redlich-Peterson, Sips, Dubinin-Radushkevich, and tang- muir isotherm models. The exothermic entbalpic values reflected a favorable energetic process for chro- mium ions anchored in the material surfaces. The negative Gibbs free energy results supported the spontaneity of three adsorption reactions with Cr（VI） ions.

Estimation on Global Reaction Heat for the Aromatization Process of Liquefied Petroleum Gas

The reaction heat effect analysis for the aromatization process of Liquefied Petroleum Gas (LPG) was completed in this paper. In order to characterize this complex reaction system, one set of independent reactions was determined by means of atomic coefficient matrix method. Based on reaction thermodynamic and stoichiometric knowledge, the heat effect, Gibbs free energy change and equilibrium constant for each independent reaction was calculated for the specified conditions. Under these conditions, based on the initial and final composition data from LPG aromatization experiments, the actual extent of reaction for each independent reaction was determined. Furthermore, the global reaction heat and adiabatic temperature rise of LPG aromatization reaction system could be estimated. This work would provide a theoretical guidance for the design and scale-up of reactor for LPG aromatization process, as well as for the selection of proper operating conditions.

Mechanism and Kinetic of Free Radical Reactions for Propane Using theoretical Calculations

Quantum calculation method has been used to understand and investigate the free radical reactions of propane with hydroxyl radical in vacuum through modem quantum mechanics that is package on hyperchem 8.02 program. Optimized structures and structural reactivates have been studied through bond stability and angles using DFT calculation based on the basis set 6-31G＊. Energetic properties have been calculated like total energy, Gibbs free energy, entropy, heat of formation, and rate constant for all chemical species that＇s participate in the suggested reaction mechanism. Reaction mechanism and rate determining step had been suggested according to calculation of energy barrier values, and compares between the suggested competitive reactions for each probable reaction step. Suggested structures and the probable transition states have been studied.

对“中等收入陷阱意识”及相关对策的批判——兼与刘伟、田国强、袁富华等商榷

我们应该警惕经济殖民地化、过度城市化、私有化、市场化、自由化(小政府化)的"拉美陷阱"。"中等收入陷阱"和"跨越中等收入陷阱",是跨国垄断资本用来误导、恐吓第三世界国家的一个臆造的概念。中国必须将国家经济治理的目标切实转向可持续的强国生民上来,只有以公有制为基础的社会主义,才能将中国从"新自由主义+凯恩斯主义"的困境中解脱出来。强国生民,应该是新时代国家经济治理的目标。

Thermodynamic modeling of ZrO_(2)−CaO−TiO_(2)system

The phase diagram of ZrO_(2)−CaO−TiO_(2)system was essential for the development of photocatalytic materials and refractory materials.In this work,the ZrO_(2)−CaO−TiO_(2)system was accessed by using the CALPHAD method.The substitutional solution models were used to describe liquid and solid solution phases,the sub-lattice models were used to describe ternary compounds,and then the thermodynamic parameters were obtained by the least square method combined with literature experiment results.The acquired thermodynamic parameters were used to calculate the isothermal sections of the ZrO_(2)−CaO−TiO_(2)system at 1473 and 1673 K.There existed a good agreement between experimental and predicted phase relationships,the experimental points which were inconsistent with calculated results may be attributed to experimental errors and the sluggish kinetics of cations for ZrO_(2)-based materials.In order to further verify the validity of the database,the thermodynamic parameters were also used to simulate the thermodynamic properties(specific heat capacity,enthalpy,and entropy)of CaZrTi_(2)O_(7) within 5%errors.Good consistency demonstrated that the present thermodynamic database was self-consistent and credible.

First-principles calculation of structural and thermodynamic properties of titanium boride

The equilibrium lattice parameters, electronic structure, bulk modulus, Debye temperature, heat capacity and Gibbs energy of TiB and TiB2 were investigated using the pseudopotential plane-wave method based on density functional theory (DFT) and the improved quasi-harmonic Debye method. The results show that the total density of states (DOS) of TiB2 is mainly provided by the orbit hybridization of Ti-3d and B-2p states, and the total DOS of TiB is mainly provided by the hybrids bond of Ti-3d and B-2p below the Fermi level and Ti—Ti bond up to the Fermi level. The Ti—B hybrid bond in TiB2 is stronger than that in TiB. Finally, the enthalpy of formation at 0 K, heat capacity and Gibbs free energy of formation at various temperatures were determined. The calculated results are in excellent agreement with the available experimental data.

诺贝尔经济学奖获得者詹姆斯·托宾逝世

2002年3月11日,耶鲁大学教授,曾担任肯尼迪总统的经济顾问,荣获1981年诺贝尔经济学奖的詹姆斯·托宾(James Tobin)逝世。托宾是美国最杰出的凯恩斯主义经济学家,他的过世堪称经济学界的一大损失。 托宾过世后,经济学界一片叹息之声,并对他给予很高的评价,伦敦《金融时报》称托宾是“一流的凯恩斯主义经济学家”;《华盛顿邮报》认为托宾是“他那一代学者中最有影响力和创造力的经济学家”。该报引用商业版编辑霍伯特·罗文的话说,“托宾的著作第一次揭示了金融资产与政府财政政策的关系。”

电化学方法测定纳米材料的热力学函数

以纳米铜为例,首次采用电化学方法获取纳米材料的热力学函数.通过电化学沉积法制备了粒子尺寸约80nm的纳米铜电极,测定纳米铜与块体铜电极的电势差,以块体铜的热力学函数值为参考标准,根据纳米铜与块体铜的热力学关系式,求得纳米铜的标准摩尔生成焓、标准摩尔生成吉布斯自由能、标准摩尔熵分别为5.16kJmol-1、0.216kJmol-1、49.75JK-1mol-1,同时,求得纳米铜可逆电池反应的热效应为-4.95kJmol-1.

CO_2 solubility in aqueous solutions of N-methyldiethanolamine+piperazine by electrolyte NRTL model

Accurate modeling of the solubility behavior of CO_2 in the aqueous alkanolamine solutions is important to design and optimization of equipment and process. In this work, the thermodynamics of CO_2 in aqueous solution of N-methyldiethanolamine(MDEA) and piperazine(PZ) is studied by the electrolyte non-random two liquids(NRTL) model. The chemical equilibrium constants are calculated from the free Gibbs energy of formation, and the Henry's constants of CO_2 in MDEA and PZ are regressed to revise the value in the pure water. New experimental data from literatures are added to the regression process. Therefore, this model should provide a comprehensive thermodynamic representation for the quaternary system with broader ranges and more accurate predictions than previous work. Model results are compared to the experimental vapor-liquid equilibrium(VLE), speciation and heat of absorption data, which show that the model can predict the experimental data with reasonable accuracy.

A Gibbs free energy formula for protein folding derived from quantum statistics

The fundamental law for protein folding is the thermodynamic principle.The amino acid sequence of a protein determines its native structure and the native structure has the minimum Gibbs free energy.Lacking of a Gibbs free energy formula is the reason that all ab initio protein structure prediction only empirical and various empirical energy surfaces or landscapes are introduced to fill the gap.We make a quantum mechanics derivation of the Gibbs free energy formula G(X)using quantum statistics for a single conformation X.For simplicity,only monomeric self folding globular proteins are considered.

Phase field simulation of solidification under supergravity

In order to understand the influence of supergravity on the microstructure of materials,crystal nucleation,dendritic growth,and polycrystal solidification under supergravity are investigated by using the modified nucleation theory and phase field models.Firstly,supergravity is considered in the nucleation theory by using pressure-dependent Gibbs free energy.It is found that the critical radius decreases and the nucleation rate increases when supergravity rises.Secondly,anisotropic heat transport is proposed in the phase field model to investigate the influence of supergravity on dendritic growth.Phase field simulations show that supergravity promotes the secondary dendritic growth in the direction parallel to supergravity.Finally,a multiply phase field model with pressure-dependent interfacial energy is employed to simulate the polycrystalline solidification under supergravity.Due to the depth-dependent pressure by supergravity,crystal grains are significantly refined by high pressure.In addition,gradient distribution of grain size is obtained in the solidification morphology of polycrystalline,which is consistent with previous experimental observations.Results of this work suggest that supergravity can be used to tune the microstructures and properties of materials.

A new association state of solutes in nanoconfined aqueous solutions

Recently, we have found a reversible transition between the dispersion and aggregation states of solute molecules in aqueous solutions confined in nanoscale geometry, where solutes exhibit distinct behavior in a new association state from that in the dispersion and aggregation states observed usually in macroscopic systems. However, it remains unknown whether this new association state of solute molecules found in nanoconfined systems would vanish with the system size increasing and approaching the macroscopic scale. Here, we achieve the phase diagram of solute association states by making the analyses of Gibbs free energy of solutes in nanoconfined aqueous solutions in detail. In the phase diagram, we observe a closed regime with a finite system size of nanoconfined aqueous solutions and a solute concentration range, only in which there exists the new association state of solutes with the reversible transition between the aggregation and dispersion states, and there indeed exists an upper limit of the system size for the new association state, around several tens nanometers. These findings regarding the intimate connection between the system size and the solute association behavior provides the comprehensive understanding of the association dynamics of solutes in nanoconfined environment.