热电厂会计行为规范体系研究

热电厂会计行为往往是通过热电厂会计行为而产生热电厂会计信息,与企业的经济后果有着重要联系。热电厂会计行为产生的热电厂会计信息已经广泛被企业运用到决策过程当中。热电厂会计行为的规范早已成为了当下最为热门的话题。我国的市场进程不断推进,热电厂的发展也相当迅猛。随着民众生活质量的提高,用电的智能化和节约化对电厂起到了不小的影响作用。在热电厂,核算和结算是重中之重。因此,在热电厂市场化的过程当中,热电厂会计行为日益显示出其重要作用来。

Mg-Si-Sn-Bi材料退火过程中微结构演变与热电性能

利用单质粉末冷压成型及高真空500℃-2 h烧结制备了Mg-Si-Sn-Bi材料,随后对制备材料在真空下600℃退火处理,并对制备材料的组成和热电性能进行研究。结果表明,500℃烧结材料仅仅由Mg_2Sn和Mg_2Si两相混合物构成。材料600℃退火,部分化合物分解,Sn和Si首先以单质形式存在;随后Si融入剩余的Mg_2Sn结构中,形成Mg_2(Sn,Si)固溶体;Sn以金属纳米尺寸状态存在;分解的Mg与真空石英玻璃管内残留的氧反应生成MgO相。而且,退火时间延长,Mg_2(Sn,Si)固溶体和纳米尺寸的金属Sn含量增多。材料中Mg_2(Sn,Si)固溶体含量越多,Seebeck系数绝对值越大;材料中纳米尺寸的金属Sn含量越多,电阻率越小。含有纳米尺寸金属Sn的Mg-Si-Sn-Bi材料因Seebeck系数绝对值大和电阻率小,具有较大的功率因子。

热透波材料技术研究进展

热透波材料技术是高超声速飞行器实现通讯与精确导航的关键技术,文章从热透波材料体系、热透波材料热电行为和高温电性能测试技术等方面对热透波材料及其相关技术的发展现状进行了简要介绍。在材料体系方面,石英陶瓷及二氧化硅基复合材料是目前应用的主要材料品种,多孔氮化物陶瓷及陶瓷基复合材料是未来发展的重要方向。在热电行为研究方面,对典型氧化物、氮化物、氮氧化物材料热电行为规律及杂质离子对材料热电行为的影响等方面的研究获得重要进展,并获得试验验证。在高温电性能测试方面,近年来突破了1 600℃高温宽频测试关键技术,并获得了氧化硅熔融态介电性能实测数据,国外和国内已实现8 MW/m2热透波实时测试。

热电材料微结构调控热电输运行为的研究进展

热电材料是绿色能源转化、温差电技术应用的关键材料。由于各性能指标相互抑制,材料热电性能改善遇到瓶颈。材料微结构设计协同调控热电性能为下一代热电材料发展提供了一条明确思路。本文介绍热电材料"多尺度微结构构筑"、"电子晶体离子液体"、"晶格缺陷工程"等改善热电性能的新概念,从原子、纳米、微米等尺度分析能带调控、弱键合、非简谐振动效应、纳米畴散射机制、调幅分解、能量过滤机制、相变现象等物理、化学过程对热电输运行为的影响;阐述了热电材料晶体微结构特征,总结了点缺陷、晶界、纳米畴等结构参量对能带结构、载流子自由程、晶格振动模式等物理参量的影响规律;展望了下一代高性能块体热电材料的发展方向。

Heat transfer behavior of AZ80-1%Y alloy during low-frequency electromagnetic casting

Heat transfer behaviors of AZ80?1%Y alloy during low frequency electromagnetic casting (LFEC) and direct chilling casting were studied by in-situ temperature measurement. The results demonstrated that the low frequency electromagnetic field (EM) caused forced convection in the melt during LFEC. The forced convection led to uniform solidification velocity and temperature field. EM frequency, excitation current intensity and casting temperature could control the heat transfer behavior. The forced convection could improve the microstructure and degrade the difference in microstructure between the edge and center of billet. Appropriate parameters of low frequency EM for casting Mg alloy are 20 Hz of frequency and 60 A of electric current intensity.

Influence of heat treatment on microstructure and electrochemical behaviors of Mg-Zn binary alloys prepared by gas-phase alloying technique

Mg-Zn binary alloys fabricated by the gas-phase alloying technique under vacuum condition were investigated in the state of initial state and after heat treatment for the microstructure and electrochemical behaviors.Different from the traditional Mg-Zn alloys preparation methods,alloys prepared by gas-phase alloying have a large number of intermetallic compounds,such as MgZn,Mg7Zn3 and MgZn2.After solution treatment,the boundary of the eutectic disappeared and the size ofα-Mg increased from 100μm to 150μm.At the same time,the value of the resistance of charge transfer increased,which indicates that the resistance of the charge transfer and the corrosion resistance of the alloys increased.After artificial aging treatment,the distribution ofα-Mg was more uniform and its size was reduced to about 50μm,and there was new eutectic structure formed.The newly formed eutectic structure forms galvanic cells with the alloy matrix,which makes the corrosion resistance of the alloy weaken.

Thermo‐driven photocatalytic CO reduction and H_(2) oxidation over ZnO via regulation of reactant gas adsorption electron transfer behavior

Photothermal catalysis is a widely researched field in which the reaction mechanism is usually investigated based on the photochemical behavior of the catalytic material.Considering that the adsorption of reactants is essential for catalytic reactions to occur,in this study,the synergistic effect of photothermal catalysis is innovatively elucidated in terms of the electron transfer behavior of reactant adsorption.For the H_(2)+O2 or CO+H_(2)reaction systems over a ZnO catalyst,UV irradiation at 25°C or heat without UV irradiation did not cause H_(2)oxidation or CO reduction;only photothermal conditions(100 or 150°C+UV light)initiated the two reactions.This result is related to the electron transfer behavior associated with the adsorption of CO or H_(2)on ZnO,in which H_(2)or CO that lost an electron could be oxidized by O2 or hydroxyls.However,the electron‐accepting CO could be reduced by the electron‐donating H_(2)into CH4 under photothermal conditions.Based on the in‐situ characterization and theoretical calculation results,it was established that the synergistic effect of the photothermal conditions acted on the(002)crystal surface of ZnO to stimulate the growth of zinc vacancies,which resulted in the formation of defect energy levels,adsorption sites,and an adjusted Fermi level.As a result,the electron transfer behavior between adsorbed CO or H_(2)and the crystal surface varied,which further affected the photocatalytic behavior.The results show that the effect of photothermal synergy may not only produce the expected kinetic energy,but more importantly,produce energy that can change the activation mode of the reactant gas.This study provides a new understanding of the CO catalytic oxidation and reduction processes over semiconductor materials.

Electrocaloric behavior of Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.88)Sn_(0.02)O_3 cement composites

A thrust for looking multifunctional materials for applications in civil engineering structures has attracted interest among researchers across the globe.Cement based Ba0.85Ca0.15Zr0.1Ti0.88Sn0.02O3(BCZT.Sn)composites were prepared for electrocaloric applications with varying BCZT.Sn to cement ratio.Hysteresis loops showed some signature of saturation in cement composites.However,loops of pure sample were saturated due to its ferroelectric nature.Furthermore,these composites were explored for the first time in solid state refrigeration technology namely electrocaloric effect(ECE).Peak electrocaloric performance shows an adiabatic temperature changes of 0.71,0.64 and 0.50 K and isothermal entropy changes of 0.86,0.80 and 0.65 J/(kg.K)for BCZT.Sn,10%and 15%cement composites,respectively,under application of 0-29 kV/cm electric field.The adiabatic temperature change in cement based composites is comparable with that of the BCZT-Sn ferroelectric ceramics.Furthermore,the dielectric constant(εr)of composites with different ceramic contents at room temperature reveals that dielectric constant increases with an increase in BCZT-Sn proportion in composites.These cement based BCZT.Sn composite materials may be used in solid state refrigeration as they are fairly competitive with the pristine sample.

New Li-ion Battery Evaluation Research Based on Thermal Property and Heat Generation Behavior of Battery

We do a new Li-ion battery evaluation research on the effects of cell resistance and polariza- tion on the energy loss in batteries based on thermal property and heat generation behavior of battery. Series of 18650 cells with different capacities and electrode materials are evalu- ated by measuring input and output energy which change with charge-discharge time and current. Based on the results of these tests, we build a model of energy loss in cells＇ charge- discharge process, which include Joule heat and polarization heat impact factors. It was reported that Joule heat was caused by cell resistance, which included De-resistance and reaction resistance, and reaction resistance could not be easily obtained through routine test method. Using this new method, we can get the total resistance R and the polarization parameter U. The relationship between R, η, and temperature is also investigated in order to build a general model for series of different Li-ion batteries, and the research can be used in the performance evaluation, state of charge prediction and the measuring of consistency of the batteries.

Area Method Analysis and Thermodynamic Behavior of Nonmetallic Micro-Inclusions in Casting Slab of GCr15 Bearing Steel

The distribution and characteristics of nonmetallic micro-inclusions of GCr15 bearing steel were explored through metallographic area method in virtue of tracer method and electronic microscope.The results show that the micro-inclusions,of which the average value is 0.032%,are mainly the compounds formed via the adsorption/aggregation of multielement deoxidized compounds and secondarily deoxidized products on tundish liquid level.The micro-inclusions of diameters from 0 to 5 μm are 92.5% in total,which basically determines the characteristics of inclusions distribution in casting slab.The inclusions of diameters more than 10 μm only account for less than 1% in total,which have little influence on steel quality.The relationship between equilibrium compositions of the first deoxidation products and molten steel compositions was also calculated based on thermodynamic theory.

Galvanic Interactions of Aluminium 3004 and ∝ Brass in Tropical Marine Atmosphere

The galvanic corrosion behaviour of alumiuium 3004 - ∝ brass with different area ratios was studied in the tropical marine atmosphere at Tuticorin harbour over a period of 426 days. The area ratios, viz. AAluminiurn：A∝ brass, studied were 0.125, 0.25, 0.5, 1, 2, 4 and 8. The galvanic corrosion behaviour of the metals was studied in terms of the relative increase in the corrosion rate of aluminium due to galvanic coupling with oc brass, the relative decrease in the corrosion rate of ∝ brass due to galvanic coupling with aluminium, and the susceptibility of aluminium to pitting owing to galvanic coupling with ∝ brass. The galvanic potential and galvanic current of the system were monitored. Pits of different dimensions ranging from mild etchings to perforations were experienced on the borders arid the surfaces of the interface of aluminium in contact with ∝ brass. The corrosion products resulting from galvanic corrosion were analysed using XRD and the pitting on aluminium as a result of galvanic corrosion was highlighted in terms of pit depth, size and density of pit, using a high resolution microscope. The most favourable area ratio of aluminium - ∝ brass in marine atmosphere in terms of gravimetric corrosion rate is 8：1 and the most unfavourable area ratio of aluminium - ∝ brass is 1：4.

Thermoelectric Behavior of Isotropically Conductive Adhesive

The paper deals with unusual use of one kind of ECA （electrically conductive adhesive）---the ICA （isotropic conductive adhesive）. The main sphere of ECA application is electronic assembly, e.g., it is bonding of semiconductor microchips on printed circuits boards. In this sphere, the ECA compete with soft solder. In spite of this fact, the author utilized of two main ECA characteristics--good electrical conductivity and excellent adhesion to material surfaces to make the fiat thermocouples. Both the design of thermocouples and the measuring device and the measuring workplace arrangement are described. The measured data of thermoelectric voltages are plotted. The thermoelectric （Seebeck＇s） coefficients were calculated from obtained dependences of thermoelectric voltage versus the temperature differences.

Fuel Cells as Energy Systems： Efficiency, Power Limits and Thermodynamic Behavior

Steady-state model of a high-temperature solid oxide fuel cell （SOFC） is considered, which refers to constant chemical potentials of incoming hydrogen fuel and oxidant. Lowering of the cell voltage below its reversible value is attributed to polarizations and imperfect conversions of reactions. An imperfect power formula summarizes the effect of transport laws, irreversible polarizations and efficiency of power yield. Reversible electrochemical theory is extended to the case with dissipative chemical reactions; this case includes systems with incomplete conversions, characterized by ＂reduced affinities＂ and an idle run voltage. Efficiency drop is linked with thermodynamic and electrochemical irreversibilities expressed in terms of polarizations （activation, concentration and ohmic）. Effect of incomplete conversions is modeled by assuming that substrates can be remained after the reaction and that side reactions may occur. Optimum and feasibility conditions are discussed for basic input parameters of the cell. Calculations of maximum power show that the data differ for power generated and consumed and depend on current intensity, number of mass transfer units, polarizations, electrode surface area, average chemical rate, etc.. These data provide bounds for SOFC energy generators, which are more exact and informative than reversible bounds for electrochemical transformation.

Effects of power-law spectrum behaviors of nonthermal electrons on a ring-beam maser instability

The electron-cyclotron maser （ECM） emission driven by nonthermal electrons is one of the most crucial mechanisms responsible for radio emissions in magnetized planets, for the interplanetary medium （IPM） and for the laboratory microwave generation devices. Major astrophysical observations demonstrate that nonthermal electrons frequently have a negative power-law spectrum with a lower energy cutoff and anisotropic distribution in the velocity space. In this paper, the effects of power-law spectrum behaviors of electrons on a ring-beam maser emission are considered. The results show that the growth rates of O1 and X2 modes decrease rapidly for small A （the dispersion of momentum u）. Because of the lower energy cutoff behavior, the nonthermal electrons with large a still can excite the ECM instability efficiently. The present analysis also includes the effects of parameter β （βu0 is the dispersion of perpendicular momentum ui, u0 the average value of u） on the instability. The growth rate of X2 mode decreases with parameter v0 （v0 = u⊥o/uo, U⊥0 is the average value of u⊥）. But for O1 mode, the relationship between the growth rate and v0 is complicated. It also shows that the growth rates are very sensitive to frequency ratio Ω （frequency ratio of electron cyclotron frequency to plasma frequency）.

In-situ TEM study of the dynamic behavior of the graphene-metal interface evolution under Joule heating

The dynamic behavior of the interface between few layer graphene(FLG) and tungsten metal tips under Joule heating has been studied by in-situ transmission electron microscopy(TEM) method. High-resolution and real-time observations show the tungsten tip ‘swallow' carbon atoms of the FLG and ‘spit' graphite shells at its surface. The tip was carbonized to tungsten carbide(WC, W_2 C and WC_x) after this process. A carbon diffusion mechanism has been proposed based on the diffusion of carbon atoms through the tungsten tip and separation from the surface of the tip. After Joule heating, the initial FLG-metal mechanical contact was transformed to FLG-WCx-W contact, which results in significant improvement on electrical conductivity at the interface.