Unraveling the effect of uniaxial strain on thermoelectric properties of Mg2Si:A density functional theory study

In this work, the effect of uniaxial strain on electronic and thermoelectric properties of magnesium silicide using density functional theory（DFT） and Boltzmann transport equations has been studied. We have found that the value of band gap increases with tensile strain and decreases with compressive strain. The variations of electrical conductivity,Seebeck coefficient, electronic thermal conductivity, and power factor with temperatures have been calculated. The Seebeck coefficient and power factor are observed to be modified strongly with strain. The value of power factor is found to be higher in comparison with the unstrained structure at 2% tensile strain. We have also calculated phonon dispersion, phonon density of states, specific heat at constant volume, and lattice thermal conductivity of material under uniaxial strain. The phonon properties and lattice thermal conductivity of Mg2Si under uniaxial strain have been explored first time in this report.

First principle investigation of the electronic and thermoelectric properties of Mg2C

In this paper, electronic and thermoelectric properties of Mg_2C are investigated by using first principle pseudo potential method based on density functional theory and Boltzmann transport equations. We calculate the lattice parameters,bulk modulus, band gap and thermoelectric properties（Seebeck coefficient, electrical conductivity, and thermal conductivity） of this material at different temperatures and compare them with available experimental and other theoretical data. The calculations show that Mg_2C is indirect band semiconductor with a band gap of 0.75 eV. The negative value of Seebeck coefficient shows that the conduction is due to electrons. The electrical conductivity decreases with temperature and Power factor（PF） increases with temperature. The thermoelectric properties of Mg_2C have been calculated in a temperature range of 100 K–1200 K.

Highly Efficient Conversion of Solar Energy by the Photoelectric Converter and a Thermoelectric Converter

The analysis of the principle operation of the solar element is given in the work. The efficiency of the creation of combined high-efficiency converters of network energy in electric and thermal is indicated. A method for creating a combined photo thermo converter with a high value of the efficiency of a solar element has been found. A method for separating light from optical lenses is shown. The calculation of the light intensity into diffraction pattern is calculated using the Huygens-Fresnel principle. A new design of a highly efficient combined light-thermal converter into an electrical, with a solar element, operating on selective photoactive radiation is presented. The process of conversion of non-active radiation into electrical radiation by means of a thermo electronic converter is described. The ways of the solution of the problem connected with the reduction of the coefficient of its full effect as a function of temperature and characteristics are indicated.

嗜热毛壳菌端粒酶的表达纯化及酶学特性分析

为进一步探究端粒酶的酶学特性,以嗜热毛壳菌(Chaetomium thermophilum, Thermo)端粒酶为研究对象,通过生物化学、生物信息学等方法得到4种不同长度的Thermo端粒酶蛋白,分别与体外转录得到的Thermo端粒酶RNA进行组装。通过端粒酶体外延伸试验检测组装体的反转录活性,进一步分析影响其反转录活性的各种因素。结果表明,4种不同长度的Thermo端粒酶蛋白重组质粒经大肠杆菌表达系统诱导表达后均可得到相应的Thermo端粒酶蛋白,且纯度均在90%以上;体外孵育试验表明,在10 mmol/L HEPES-KOH(pH 8.0)、1 mmol/L MgCl2、100 mmol/L NaCl、3 mmol/L KCl、体积分数25%Glycerol、10units/μL Rnasin的条件下,端粒酶蛋白与RNA的摩尔浓度比达到1∶1及以上时,两者能有效复合;端粒酶体外延伸试验发现,结构完整的Thermo端粒酶组装体具有很强的反转录活性,可使18nt-DNA引物反复延伸。TEN结构域不完整并未减弱Thermo端粒酶组装体的反转录活性,说明其在反转录过程中未发挥显著作用。T-PK区或TWJ区缺失的组装体均不能使18nt-DNA引物发生延伸,表明RNA结构的完整性是端粒酶发挥反转录功能的必要条件。

A Wavy-Structured Highly Stretchable Thermoelectric Generator with Stable Energy Output and Self-Rescuing Capability

Thermoelectric generators(TEGs)demonstrate great potential for flexible and wearable electronics due to the direct electrical energy harvested from waste heat.Good wearability requires high mechanical flexibility and preferable stretchability,while current TEGs are primarily developed with rigid or non-stretchable components,which do not conform well to human skin or accommodate human motions,thus hindering further applications.

THE ON-LINE WELL-ADAPTIVE MECHANISM IN THERMOELECTRIC TECHNIQUE OF TEMPERATURE MEASUREMENT

Thermocouple has been widely used in scientific research works and industrial processes as the modern and popular means for measuring temperature, especially for measuring high as well as low temperature. The physical principle, upon which this kind of temperature measurement is based, is the thermoelectric effect, and its macroscopic description can be written as follows:

The role of temperature‐enhanced fault closure in promoting postinjection pressure diffusion and seismicity in enhanced geothermal systems

Post shut‐in seismic events in enhanced geothermal systems(EGSs)occur predominantly at the outer rim of the co‐injection seismic cloud.The concept of postinjection fracture and fault closure near the injection well has been proposed and validated as a mechanism for enhancing post shut‐in pressure diffusion that promotes seismic hazard.This phenomenon is primarily attributed to the poro‐elastic closure of fractures resulting from the reduction of wellbore pressure after injection termination.However,the thermal effects in EGSs,mainly including heat transfer and thermal stress,may not be trivial and their role in postinjection fault closure and pressure evolution needs to be explored.In this study,we performed numerical simulations to analyze the relative importance of poro‐elasticity,heat transfer,and thermo‐elasticity in promoting postinjection fault closure and pressure diffusion.The numerical model wasfirst validated against analytical solutions in terms offluid pressure diffusion and against heatedflow‐through experiments in terms of thermal processes.We then quantified and distinguished the contribution of each individual mechanism by comparing four different shut‐in scenarios simulated under different coupled conditions.Our results highlight the importance of poro‐elastic fault closure in promoting postinjection pressure buildup and seismicity,and suggest that heat transfer can further augment the fault closure‐induced pressure increase and thus potentially intensify the postinjection seismic hazard,with minimal contribution from thermo‐elasticity.

基于微观偏析统一模型及Thermo-Calc的三元合金凝固路径耦合计算

将合金凝固微观偏析统一模型推广到三元合金凝固微观偏析的预测,并提出了能够计算三元匀晶与共晶合金凝固路径的数值计算方法.实现了在源代码层次上与热力学计算软件Thermo-Calc及其数据库的耦合,以获取多元合金凝固路径计算所需的凝固热力学数据.通过Fe-40V-40Cr,Al-4.5Cu 1.0Si.Al 10Cu 2.5Mg和Al-1.49Si-0.64Mg(质量分数,%)等多元/多相合金在不同冷速下凝固路径的实例计算,以及与相应的凝固组织定量金相实验结果对比,验证了本文多元/多相凝固模型和算法的正确性.

15Cr系高铬铸铁组织特征的热力学分析

利用Thermo Calc软件对不同铬碳比的15Cr系高铬铸铁凝固过程、平衡相数量及其组成进行了查证和计算,在此基础上揭示了该类铸铁的组织特点及其影响因素。结果表明,15Cr系高铬铸铁的铸造工艺性能和平衡相数量及其组成均可通过铬碳比这一指标进行调节,而影响其二次碳化物析出和共析转变过程的主要因素是冷却条件;铬碳比的选择应根据高铬铸铁的服役条件而定。Thermo Calc软件预测结果与实际情况基本上相符,结论可用于指导该类产品的研究与开发。

降Al提Cr对低膨胀Thermo-Span合金性能的影响

研究了改变Thermo-Span合金的Al,Cr含量对合金热膨胀系数、力学性能和650℃氧化性能的影响。当合金中Al含量由0.45%提高到1.5%,Cr含量由5.5%降低到3.0%,合金20～800℃的膨胀系数显著降低,650℃,600MPa的光滑持久性能由354h提高到597h,室温拉伸强度明显增大,650℃,100h氧化速率稍有提高。Al含量增加,γ′相析出增多。Cr含量较高时,氧化层和基体界面处的Cr浓度较高,提高了抗氧化性。降低Cr含量,提高Al含量,氧化层与基体界面处的Cr富集程度降低,Al的富集程度提高,合金的抗氧化性虽然有所降低,但幅度不大,仍保持为完全抗氧化级别。

铁素体不锈钢410S与430高温相组织的Thermo-calc计算与试验研究

通过金相观察与DSC试验,对410S和430两种铁素体不锈钢的高温组织进行了研究,并通过定量分析,分别获得了高温相组织的体积分数及与温度的变化关系。利用Thermo-calc热力学软件,计算了两钢种的高温相图,计算结果和试验结果吻合较好。由于高温下铁素体不锈钢存在两相组织,钢的热塑性会降低,导致轧制时产生边裂,故探讨了通过热加工工艺优化来避免边裂的问题。

水相体系酶法制备甘油磷脂酰乙醇胺的研究

研究了水相体系中脂肪酶Thermo 4S-3水解大豆粉末磷脂制备甘油磷脂酰乙醇胺(L-α-GPE)的可行性,探讨了反应条件对磷脂酰乙醇胺(PE)转化率和L-α-GPE得率的影响。确定脂肪酶Thermo 4S-3催化制备L-α-GPE的最佳反应条件为:pH 7,底物质量浓度5 mg/mL,反应温度40℃,酶添加量30 U/mL,CaCl2添加量3.33 mg/mL,反应时间6 h。在最佳反应条件下,PE转化率为95.5%,L-α-GPE得率为93.6%。

硬质合金刀具切削过程中扩散磨损的数值模拟

针对硬质合金刀具切削奥氏体不锈钢粘刀现象严重的问题,利用热力学软件Thermo-Calc中的TCC模块和D ICTRA模块,模拟了硬质合金刀具与被切削工件之间发生的原子扩散.主要对Fe-Co、Cr-Co、N i-Co、Mn-Co元素之间的相互扩散以及C在刀具表面的富集情况进行模拟.证实刀具与工件之间发生的原子间相互扩散是发生粘刀现象的主要原因.

数值模拟在宝钢不锈钢研发中的应用

对宝钢应用热力学数值模拟软件Thermo-Calc进行不锈钢的合金设计、工艺设计、产品使用技术研究等进行回顾与总结,并讨论了数值模拟在不锈钢研发中的局限性与发展前景。实践证明,将数值模拟与试验有效结合可以指导不锈钢产品从设计到制造到使用的全流程研发。随着不锈钢新品种与新工艺的不断出现,通过不断完善数据库与模型,强化功能,不断积累实践的数据与经验,数值模拟将在不锈钢研发中发挥越来越重要的作用。

水相体系酶法制备甘油磷脂酰胆碱的研究

研究了脂肪酶(Thermo4S-3)在水相体系中制备甘油磷脂酰胆碱(GPC)的可行性,并探讨了脂肪酶水解条件对GPC得率的影响。实验结果表明脂肪酶(Thermo4S-3)可以实现豆粉末磷脂的水解反应,具有制备甘油磷酸胆碱(GPC)的工业应用前景。正交实验优化结果如下:反应温度40℃,底物浓度33.3g/L,酶添加量30U/mL,CaCl2添加量2g/L。利用HPLC-ELSD进行定量分析,GPC得率达到96.5%。LC-MS/MS定性分析,GPC的结构与标样分析的一致。

热力学计算在SnAgCu合金成分设计中的应用

随着计算机技术的发展，采用CALPHAD的方法对钎料合金系统进行最佳合金成分预测成为可能，通过对SnAgCu三元合金系建立亚规则溶体热力学模型，利用Thermo—CaLc计算软件数据库，根据“吉布斯自由能最小值的方法”和“平衡相各组元化学势相等”的原则，确定了最优合金成分相的范围w（Sn）（3～4）％，w（Ag）（0．5～0．9）％，其余为Cu，共晶温度为217℃。用DSC测热的结果与热力学计算的熔化温度值相比较，二者结论基本一致。

浅析Thermo 6300电感耦合等离子体发射光谱仪及其在矿石分析中的应用

本文对美国热电公司的第三代电感耦合等离子体发射光谱仪Thermo 6300的原理、结构及使用进行了阐述,并对其在矿石分析中的应用进行了综述。

低活性Fe-Cr-Mn(W,V)合金相稳定性的实验与热力学计算

采用实验和Thermo Calc热力学计算方法对4种不同成分的Fe-Cr-Mn(W,V)合金(1#、2#、3#、4#合金)的相稳定性进行了研究.实验结果表明,4种合金在623K、673K和773K下时效200h后的主导相为较稳定的奥氏体相.基于热力学自由能的Thermo-Calc计算结果表明:4种合金在实验对应温度下的金相组织为稳定的奥氏体相,计算结果与实验结果有较好的一致性.

To the Question about the Nature and Structure of Jupiter’s Magnetic Field

There was elaborated a method for calculating magnetic fields of the Solar System planets. It is based on the quantum theory of electroconductivity of metals and semiconductors. The latter helps to calculate thermoelectrical processes, always taking place in the bowels of “hot” planets. Main elements of those processes are planetary temperature gradients, thermo electromotive force and radially directed thermoelectrical currents, which are associated with Seebeck effect. Thermo electromotive force causes directional movement of planetary thermoelectrical currents both in metal cores and other conductive shells of planets. Those currents are big and they generate magnetic fields of proportional intensity. The capacities of the calculation method were tested while finding the reason why the Jupiter magnetic field is such complicated. As a result it was specified that the source of the main magnetic field of a planet is its metal core and the source of an additional magnetic field is the layer of liquid metal hydrogen. There was also found the third source of a local magnetic field of low intensity along the circular zone of the equatorial region. The conclusion that the Jupiter’s main magnetic field has a polarity opposite to the Earth’s one.

ZG1Cr10MoWVNbN耐热钢平衡析出相的热力学计算及分析

采用了Thermo-Calc软件,对ZG1Cr10MoWVNbN耐热钢在400～1 600℃间存在的平衡相进行了计算分析,并就合金元素钼、钨、铌、钒对主要析出相的影响进行了分析。结果表明:耐热钢碳的质量分数为0.11%时,1 200℃淬火后的基体组织为单一马氏体;主要平衡析出相有MX、M_(23)C_6和Laves相,它们的开始析出温度分别为1 190,880,780℃;先析出富铌的MX,再析出富钒的MX;钼的质量分数大于1.5%时会形成对钢有害的M_6C型碳化物;钨能促进对钢具有强化作用的Laves相的析出。