C4F7N/CO2和C4F7N/N2混合气体热力学物性参数计算

环保型绝缘介质C4F7N及其混合气体的热力学物性参数的研究对了解其使用范围及应用前景具有参考价值。因此,采用Riedel蒸气压方程和Raoult定律计算了不同混合配比下C4F7N/CO2和C4F7N/N2混合气体的饱和蒸气压;基于P-R状态方程计算了C4F7N/CO2和C4F7N/N2的压缩因子和密度,根据分子结构特征,采用Joback基团贡献法和Thodos法计算分析了两种混合气体的定压比热容和粘度。计算结果表明:若要气体绝缘开关设备和气体绝缘输电管道在0.5MPa下运行时绝缘介质的液化温度≤253K,混合气体中C4F7N摩尔分数分别应≤8%和≤10%,该摩尔分数下混合气体各自的全球变暖潜能值分别约为SF6的2.45%和3.83%,温室效应较小。上述条件下,两种混合气体均趋于理想气体状态,压缩因子接近于1,两种混合气体中的C4F7N含量虽少,但对其混合气体的定压比热容贡献较大,而对粘度贡献不大。所得结果可为C4F7N/CO2和C4F7N/N2两种环保混合气体熄弧特性及其在GIS和GIL中的应用研究提供基础数据。

HFC-227ea热力学物性的分子动力学模拟

利用分子动力学模拟算法研究了七氟丙烷 (HF C-2 2 7ea)的热力学物性。通过将 HFC-2 2 7ea作为极性的两质点 L ennard-Jones流体处理建立了相应的势能模型。利用等温等压系综 +测试粒子 (NPT+ Test Particle)算法对 HF C-2 2 7ea的气液相平衡性质、过冷液和过热蒸气性质进行了模拟。模拟结果与美国国家标准研究所 (NIST)的数据库的最大相对偏差分别在 1.3 % (单相区 )和 1.6% (气液平衡区 )以内 。

绿色环保制冷工质的热物性研究工作蓬勃展开

一、会议概况 我于今年6月25日-30日赴美参加了在美国Boulder召开的第十四届热物性会议。这是从1959年以来每三年召开的一次盛大国际性流体和固体热物性会议。此次会议发表了约600多篇学术论文,还有颇为关注的领域的邀请报告。会议的内容涉及流体和固体的热力学和输运物性,其中几个专题分别为热物性的声学、光学。

Effect of heat treatment on microstructure and tensile strength of NiCoCrAl alloy sheet fabricated by EB-PVD

The NiCoCrAl alloy sheet was fabricated by electron beam physical vapor deposition technique and the effects of the heat treatment on the microstructure and tensile strength of the NiCoCrAl alloy sheet were investigated. The heat treatment at 1050 °C is favorable to improve the interface bonding between the columnar structures due to the disappearance of the intergranular gaps. Comparing with the thin NiCoCrAl alloy sheet before heat treatment, the Ni3Al phase appears in the NiCoCrAl alloy sheet after heat treatment, which is favorable to improve the interface bonding between the columnar structures. The increase in the tensile strength and elongation is attributed to the improvement of the interface bonding between the columnar structures. The residual stress in the NiCoCrAl alloy sheet after heat treatment is reduced significantly, which also confirms that the interface bonding is improved by the heat treatment.

Determination on Biological Characteristics of Nematode Rhabditis(Oscheius)sp.

[ Objective] The study was aimed to determine the biological characteristics of Rhabditis （Oscheius） sp. isolated from a rhizosphere soil of alfalfa field in Hailar City, Hulunbuir League, Inner Mongolia Autonomous Region. [ Method] The last instar larvae of Galleria mellonella and Tenebrio molitor were used as insect hosts. The infectivity of nematode was determined, and its heat tolerance ability was measured by using water bath method. [Result] The infectivity of the nematodes was lower at the dosages of 10, 20 and 40 IJs/larva, but higher at the dosages of 80,160, 32.0 and 640 IJs/larva. The corrected mortality （CM） of G. mellonella at 96 h and T. molitor at 120 h were both above 90%. The nematode infectivity was highest at the dosage of 80 IJs/larva when the hosts＇ CM reached 100% after 120 h. About 25% nematode individuals could survive in 36℃ water bath for 2 d in the densities of 1 000 -5 000 IJ/ml, after 6 d, there were still 3% -9% individuals survived, until 9 d the nematodes died totally. A hundred percent of the nematode individuals died in 38℃ and 40 ~C water bath after 6 h and 2 h, respectively. [Conclusion] Rhabditis （ O. ） sp. has a higher potential to cause the host mortality and represents heat tolerance up to 36℃.

Elastic and thermodynamic properties of Re_2N at high pressure and high temperature

First principles calculations are preformed to systematically investigate the elastic and thermodynamic properties of Re2N at high pressure and high temperature. The Re2N exhibits a clear elastic anisotropy and the elastic constants C11 and C33 vary rapidly in comparison with the variations in C12, C13 and C44 at high pressure. In addition, bulk modulus B, elastic modulus E, and shear modulus Gas a function of crystal orientations for Re2N are also investigated for the first time. The tensile directional dependences of the elastic modulus obey the following trend： [0001] [1211] [1010] [1011]EEEE〉〉〉 . The shear moduli of Re2N within the （0001） basal plane are the smallest and greatly reduce the resistance of against large shear deformations. Based on the quasi-harmonic Debye model, the dependences of Debye temperature, Grüneisen parameter, heat capacity and thermal expansion coefficient on the temperature and pressure are explored in the whole pressure range from 0 to 50 GPa and temperature range from 0 to 1600 K.

Microstructures and properties of welded joint of aluminum alloy to galvanized steel by Nd:YAG laser + MIG arc hybrid brazing-fusion welding

According to the differences in melting point between aluminum alloy and steel, 6013-T4 aluminum alloy was joined to galvanized steel by large spot Nd：YAG laser ＋ MIG arc hybrid brazing-fusion welding with ER4043（AlSi5） filler wire. The microstructures and mechanical properties of the brazed-fusion welded joint were investigated. The joint is divided into two parts of fusion weld and brazed seam. There is a zinc-rich zone at fusion weld toe, which consists of α（Al）-Zn solid solution and Al-Zn eutectic. The brazed seam is the Fe-Al intermetallic compounds （IMCs） layer of 2-4μm in thickness, and the IMCs include FeAl2, Fe2Al5 and Fe4Al13. FeAl2 and Fe2Al5 are located in the compact reaction layer near the steel side, and Fe4Al13 with tongue shape or sawtooth shape grows towards the fusion weld. The tensile strength of the joint firstly increases and then decreases as the welding current and laser power increase, the highest tensile strength can be up to 247.3 MPa, and the fracture usually occurs at fusion zone of the fusion weld. The hardness is the highest at the brazed seam because of hard Fe-Al IMCs, and gradually decreases along the fusion weld and galvanized steel, respectively.

Mechanical and thermo-physical properties of rapidly solidified Al-50Si-Cu(Mg) alloys for thermal management application

Al-high Si alloys were designed by the addition of Cu or Mg alloying elements to improve the mechanical properties. It is found that the addition of 1 wt.% Cu or 1 wt.% Mg as strengthening elements significantly improves the tensile strength by 27.2% and 24.5%, respectively. This phenomenon is attributed to the formation of uniformly dispersed fine particles(Al2Cu and Mg2Si secondary phases) in the Al matrix during hot press sintering of the rapidly solidified(gas atomization) powder. The thermal conductivity of the Al-50 Si alloys is reduced with the addition of Cu or Mg, by only 7.3% and 6.8%, respectively. Therefore, the strength of the Al-50 Si alloys is enhanced while maintaining their excellent thermo-physical properties by adding 1% Cu(Mg).

Studies on Thermodynamic Properties of Some Imidazolinone Derivatives in DMF at 308.15 K

Density,ultrasonic velocity and viscosity of imidazolinone derivatives are studied in dimethyl formamide(DMF) at 308.15 K.From the experimental data,various acoustical parameters,such as specific impedance Z,isentropic compressibilityκs,Rao's molar sound function Rm,van der Waals constant b,relaxation strength r,intermolecular free length Lf,internal pressureπ,solvation number Sn,relative association RA,etc.are evaluated,which helps in understanding the molecular interactions occurring in these solutions.

VARIATION IN MEMBRANE PROPERTIES FROM THE ACTION OF LAMININ ON MEMBRANE RECEPTORS

Biophysical studies were conducted on the action of laminin through membrane receptors of cancer cells. The results showed that variations occurred in the thermodynamic properties of membrane proteins,the mobility of hydrocarbon chains of membrane lipids, and the permeability and transportation pathways of the membrane.

Thermodynamic reassessment of Ga-Hg and Mg-Hg systems

The Ga-Hg binary system was thermodynamically assessed by the CALPHAD method, but only configuration contributions were considered to the entropy of the liquid. The Mg-Hg binary system has not been assessed yet. In the assessments of the Ga-Hg and Mg-Hg binary systems, solutions including liquid and hcp (Mg) were treated as substitution solutions, of which the excess Gibbs energies were formulated with the Relich-Kister polynomial. The intermetallic phases in the Mg-Hg binary system, Mg3Hg, Mg5Hg2, Mg2Hg, Mg5Hg3, MgHg, and MgHg2, were described as stoichiometric compounds. Based on the reported experimental data and thermodynamic properties of the phase diagram, sets of self-consistent parameters describing all phases in the Ga-Hg and the Mg-Hg binary systems were obtained.

Integrability of a New Type of Deformed XXZ Model

A new type of deformed XXZ model was constructed and diagonalized by the coordinate Bethe ansatz method. We obtained the energy and the Bethe ansatz equations of the model and also discussed some thermodynamics of the model.

Thermal Dynamics Behavior of Protoneutron Star Matter

In the relativistic σ-ω model, including the vacuum fluctuation of nucleons and σ mesons, the effect of the temperature to the composition and equation of state of protoneutron star matter, nucleon effective mass and chemical potential of neutrons and electrons are studied. We find that the influence of the temperature on the equation of state of protoneutron star matter is indeed small, however, its influence on the composition of protoneutron star, which will contribute to the evolution of protoneutron star, cannot be neglected in low density region. The chemical potentials of neutrons and electrons also depend on the temperature in almost the same density region.

Thermodynamic Properties of Caprolactam Ionic Liquids

A series of caprolactam ionic liquids(ILs) containing incorporated halide anions were synthesized.Their physical properties,such as melting points,heats of fusion and heat capacities,were measured by differential scanning calorimeter(DSC).The results indicate that these ionic liquids exhibit proper melting points,high value of heats of fusion,and satisfying heat capacities which are suitable for thermal energy storage applications.

Structural and Thermodynamic Properties of TiAl intermetallics under High Pressure

The structural and thermodynamic properties of TiAI intermetallics under high pressure have been investigated by ab initio plane-wave pseudopotential density functional theory method. It is found that the ratio of lattice parameter c to a keeps almost constant with a value of 1.02 under the pressure from 0 to 20 GPa, which agrees well with the experimental results. With the pressure increasing from 20 to 45 GPa the values of c/a decrease almost linearly from 1.02 to 0.99. These calculated results indicate under low pressure the variation rate for a-axis is almost the same to that for c-axis, but under higher pressure the variation for a-axis is smaller than along e-axis. Through the quasi-harmonic Debye model, the equation of state （EOS） of TiAI intermetallies, as well as the thermal expansion and heat capacity at various pressures and temperatures are also studied.

Investigations on the Thermodynamic Stability and Availability of Nutrients for Plants by Humic Substances Extracted from Peat Samples

This work evaluated the complexation capacity, exchange constants and availability of micronutrients for plants and humic substances extracted from peat samples. Samples of humic substances extracted from two tropical peats （HS-P1 and HS-P2） were enriched with the micronutrients Cu（II）, Co（II）, Fe（II）, Mn（II）, Ni（II） and Zn（II） and the parameters for formation of the complexes （HS-N） were evaluated at different pH. The Scatchard model was used to calculate the maximum complexation capacity and the nutrient availability was studied using exchange capacity experiments based on ultrafiltration procedure. The optimum pH for complexation was 4.5 and the order of affinity was： Fe（II） 〉 Cu（II） 〉 Co（II） 〉 Mn（II） = Ni（II） 〉 Zn（II）. The maximum complexation capacity reached 56.8 mg·g-1 Fe of HS-P1 （the highest） and 1.7 mg.g1 Zn of HS-P2 （the slightest）. The exchange experiments showed that HS-P-Fe complexes were formed preferentially. The least stable complex was formed with Zn, which was therefore, more easily available. The results contribute to understand the behavior and availability of some nutrients in soils.

Impact of load impedance on the performance of a thermoacoustic system employing acoustic pressure amplifier

An acoustic pressure amplifier (APA) is capable of improving the match between a thermoacoustic engine and a load by elevating pressure ratio and acoustic power output. A standing-wave thermoacoustic engine driving a resistance- and-compliance (RC) load through an APA was simulated with linear thermoacoustics to study the impact of load impedance on the performance of the thermoacoustic system. Based on the simulation results, analysis focuses on the distribution of pressure amplitude and velocity amplitude in APA with an RC load of diverse acoustic resistances and compliance impedances. Variation of operating parameters, including pressure ratio, acoustic power, hot end temperature of stack, etc., versus impedance of the RC load is presented and analyzed according to the abovementioned distribution. A verifying experiment has been performed, which indicates that the simulation can roughly predict the system operation in the fundamental-frequency mode.

Thermodynamics of Systems： Photopolymers-Low-Molecular Liquids

Photopolymers （printing flexoforms） during their operation interact with solvents and properties and ultimately reduces printing quality. A purpose of the work was to study the photopolymer with low-molecular liquids by two independent methods （chromatography and mathematical model of the process the thermodynamic properties and Flory-Huggins polymer-solvent systems. swell. Swelling changes the elastic thermodynamics of interaction of swelling in solvents）. By using a parameters were determined for

Non-isothermal curing kinetics and thermal properties of benzoxazine-phenolic copolymers

Using novolac phenolic resin, aniline and formaldehyde as raw materials, benzoxazine-phenolic copolymers with different percentages of benzoxazine rings were prepared. FT-IR was adopted to characterize the molecular structure of the novolac-type phenolic resin and the benzoxazine-phenolic copolymer BP31. In order to understand the curing process of the copolymers, the curing behavior and curing kinetic characteristics were studied by differential scanning calorimetry （DSC）, and the catalytical effect of phenolic hydroxyl on the curing behavior of copolymers was investigated. To investigate the thermal properties of this resin, the thermal degradation behaviors of the cured samples were studied by thermal gravimetric （TG） method, and glass-transition temperatures （Tg） of the cured copolymers were also evaluated by DSC. The dynamic Ozawa method was adopted to determine the kinetic parameters of the curing process as well. The activation energy is 78.8 kJ/mol and the reaction rate constant is in the range from 40.0 to 5.2 （K/min）＂ according to reaction temperatures. The Ozawa exponent decreases from 2.4 to 0.7 with the increase of reaction temperature, and curing mechanism is expounded briefly according to the results. TG result shows that the highest char yield of copolymers is 50.3%. The highest Tg of copolymers is 489 K, which is much higher than that of pure benzoxazine resin.

First Principles Study of AI-Li Intermetallic Compounds

The structural properties, heats of formation, elastic properties, and electronic structures of four compositions of binary A1-Li intermetallics, A13Li, A1Li, A12Li3, and A14Li9, are ana- lyzed in detail by using density functional theory. The calculated formation heats indicate a strong chemical interaction between A1 and Li for all the A1-Li intermetallics. In partic- ular, in the Li-rich A1-Li compounds, the thermodynamic stability of intermetallics linearly decreases with increasing concentration of.Li. According to the computational single crystal elastic constants, all the four A1-Li intermetallic compounds considered here are mechani- cally stable. The polycrystalline elastic modulus and Poisson＇s ratio have been deduced by using Voigt, Reuss, and Hill approximations, and the calculated ratios of bulk modulus to shear modulus indicate that the four compositions of binary A1-Li intermetallics are brittle materials. With the increase of Li concentration, the bulk modulus of A1-Li intermetallics decreases in a linear manner.