关于对国内生产总值发展速度计算合理性的检验

关于对国内生产总值发展速度计算合理性的检验江西省统计局戴玲玲针对国内生产总值（亦称ＧＤＰ）报表中经常出现的总量变动与现实价格变动不相符合的问题，现介绍一种简便的检验方法，用于发现问题。我们先来分解一个比数（为简写之便，设该比数为Ｒ），即Ｒ＝当年现价Ｇ...

施工用电价格在抽水蓄能电站概估算编制中的合理性计算

目前水电行业内工程造价专业人员对抽水蓄能电站工程投资计算中组成基本电价的政府性基金及附加是否含增值税,分歧较大,难以形成统一的认识。笔者对该分歧问题进行详细的调查研究,并结合相关政策文件进行验证分析。结果表明,政府性基金及附加含增值税。该研究成果为施工用电价格在抽水蓄能电站概估算编制中的合理性计算提供依据。

论体外预应力筋加固混凝土梁正截面承载能力计算的合理性

按照惯例,在计算体外预应力筋加固混凝土梁正截面承载能力时,体外筋的作用是按有黏结受拉钢筋对待的,即作为构件承载力的一部分。通过计算理论及计算示例来论证这一做法的不合理性,说明目前计算方法的力学概念不清、平截面假定有更多的不符,同时在正截面承载力、斜截面承载力计算和正截面应力计算的许多方面,体外筋作为有黏结受拉钢筋处理是前后相互矛盾的。应该将体外预应力筋的作用作为作用效应的一部分考虑,将其视为计算截面作用效应组合中的卸载作用效应,从而消除当前计算方法中的不合理性。

First principles calculation of intermetallic compounds in FeTiCoNiVCrMnCuAl system high entropy alloy

The structural, electronic and elastic properties of common intermetallic compounds in FeTiCoNiVCrMnCuAI system high entropy alloy were investigated by the first principles calculation. The calculation results of formation enthalpy and cohesive energy show that FeTi, Fe2Ti, AlCrFe2, Co2Ti, AlMn2V and Mn2Ti phases may form in the formation process of the alloy. Further studies show that FeTi, FezTi, AlCrFe2, Co2Ti and AlMn2V phases with higher shear modulus and elastic modulus would be excellent strengthening phases in high entropy alloy and would improve the hardness of the alloy. In addition, the partial density of states was investigated for revealing the bonding mode, and the analyses on the strength of p-d hybridization also reveal the underlying mechanism for the elastic properties of these compounds.

First principles investigation of binary intermetallics in Mg-Al-Ca-Sn alloy:Stability,electronic structures,elastic properties and thermodynamic properties

The structural stability, electronic structures, elastic properties and thermodynamic properties of the main binary phases Mg_（17）Al_（12）, Al_2Ca, Mg_2 Sn and Mg_2 Ca in Mg-Al-Ca-Sn alloy were determined from the first-principles calculation. The calculated lattice parameters are in good agreement with the experimental and literature values. The calculated heats of formation and cohesive energies show that Al_2Ca has the strongest alloying ability and structural stability. The densities of states（DOS）, Mulliken electron occupation number, metallicity and charge density difference of these compounds are given. The elastic constants of Mg_（17）Al_（12）, Al_2Ca, Mg_2 Sn and Mg_2 Ca phases are calculated, and the bulk moduli, shear moduli, elastic moduli and Poisson ratio are derived. The calculations of thermodynamic properties show that the Gibbs free energies of Al_2Ca and Mg_2 Sn are lower than that of Mg_（17）Al_（12）, which indicates that Al_2Ca and Mg_2 Sn are more stable than Mg_（17）Al_（12） phase. Hence, the heat resistance of Mg-Al-based alloys can be improved by adding Ca and Sn additions.

A first-principles study on electronic structure and elastic properties of Al_4Sr, Mg_2Sr and Mg_(23)Sr_6 phases

The electronic structures and mechanical properties of Al4Sr, Mg2Sr and Mg23Sr6 phases were determined by the use of first-principles calculations. The calculated heat of formation and cohesive energy indicate that Al4Sr has the strongest alloying ability as well as the highest structural stability. The elastic parameters were calculated, and then the bulk modulus, shear modulus, elastic modulus and Poisson ratio were derived. The ductility and plasticity were discussed. The results show that Al4Sr and Mg2Sr phases both are ductile, on the contrary, Mg23Sr6 is brittle, and among the three phases, Mg2Sr is a phase with the best plasticity.

从一道高考题看中学数学素质教育中存在的问题

我们通过１９８７年高考中一道试卷的阅卷分析，指出了在当前中学教学中存在的问题及向素质教育转轨的必要．

日本学者碓井敏正谈市场与计划相结合的社会主义体制以及“新型的人”等问题

日本学者碓井敏正谈市场与计划相结合的社会主义体制以及＂新型的人＂等问题冯雷编译１９９２年日本＂唯物论研究协会＂选编的论文集《社会主义哲学化－－从失败中发现的道理》，收入了日本京都桔女子大学教授雄井敏正的论文－－《社会主义体制下的市场与民主主义的问题》...

First-principles calculation of structural and elastic properties of Pd_(3-x)Rh_xV alloys

The structural stability, electronic and elastic properties of Pd3-xRhxV alloys with L12 and D022 structures were investigated theoretically by the first-principles calculations. The results reveal that with the increase of Rh content, the unit cell volume of Pd3-xRhxV alloys with L12 and D022 structures decreases, and the structure of Pd3-xRhxV alloys tends to transform from D022 to L12. The elastic parameters such as elastic constants, bulk modulus, shear modulus, elastic modulus, and Poisson ratio, were calculated and discussed in details. Electronic structures were also computed to reveal the underlying mechanism for the stability and elastic properties.

Review of micro-scale and atomic-scale corrosion mechanisms of second phases in aluminum alloys

Localized corrosion of aluminum(Al)alloys,such as pitting corrosion,intergranular corrosion,and stress corrosion cracking is closely related to the micro-galvanic corrosion between the second phase and the Al matrix.Using high-resolution transmission electron microscopy and first principles calculations,the factors that affect corrosion mechanisms of the second phase in Al alloys at micro-scale and atomic-scale were examined,including the composition and structure of second phase,pH of the environment,stress and adsorption behavior of adsorbates(such as Cl^(−),H_(2)O,OH−and O_(2)^(−).

Extensive Computational Study on Conformations of Microsolvated Leucine Complexes

The conformations for leucine （Leu） hydrated with one to three water molecules, Leu-（H2O）n （n=1-3）, were carefully searched by considering the trial structures generated by all possible combinations of rotamers of Leu combined with all likely hydration modes. The structures were optimized at the BHandHLYP/6-31＋G^＊ level and the single point energies were calculated at the BHandHLYP/6-311＋＋G^＊＊ level. Good correspondence between the conformations of Leu-（H2O）n and bare Leu is found, showing that the conformations of Leu-（H2O）n may be efficiently and reliably determined by the hydration of Leu conformers. The simulated IR spectra of canonical and zwitterionic conformers of Leu-（H2O）n are compared with the experimental result of Leu in aqueous solution. The IR spectrum of zwitterionic Leu- （H2O）3 provides the best description of the experiment. The result demonstrates that the IR spectrum of solute in solution may be simulated by the solute hydrated with an adequate number of water molecules in the gas phase.

First-principles investigation of cohesive energy and electronic structure in vanadium phosphides

First-principles calculations based on the density-functional theory were employed to study the crystal structure of vanadium phosphide compounds,such as V3P,V2P,VP,VP2 and VP4. Cohesive energy of five types of vanadium phosphide compounds was calculated to assess their structural stability. The charge density distribution and densities of states of vanadium phosphides were discussed to study further their electronic structures. The results show that the structure of metal-rich compounds is considerably more stable than the phosphorus-rich compositions,and covalent bond exists between the V and P atoms of V3P,V2P,VP,VP2 and VP4.

g-C3N4/SnS2 Heterostructure： a Promising Water Splitting Photocatalyst

Graphite-like carbon nitride （g-C3N4） based heterostrutures has attracted intensive attention due to their prominent photocatalytic performance. Here, we explore the g-CaN4/SnS2 coupling effect on the electronic structures and optical absorption of the proposed g-CaN4/SnS2 heterostructure through performing extensive hybrid functional calculations. The obtained geometric structure, band structures, band edge positions and optical absorptions clearly reveal that the g-C3N4 monolayer weakly couples to SnS2 sheet, and forms a typical van der Waals heterojunction. The g-C3N4/SnS2 heterostructure can effectively harvest visible light, and its valence band maximum and conduction band minimum locate in energetically favorable positions for both water oxidation and reduction reactions. Remarkably, the charge transfer from the g-C3N4 monolayer to SnS2 sheet leads to the built-in interface polarized electric field, which is desirable for the photogenerated carrier separation. The built-in interface polarized electric field as well as the nice band edge alignment implys that the g-CaN4/SnS2 heterostructure is a promising g-CaN4 based water splitting photocatalyst with good performance.

Density Functional Theory and Electrochemistry Studies on LiFexMn1-xPO4 Solid Solutions

The thermodynamic stability and lithiated/delithiated potentials of LiFexMn1-xPO4 were studied with density functional theorical calculations. The results show that the formation free energy of the LiFexMn1-xPO4 solid solution is slightly higher than that of the phase-separated mixture of LiFePO4 and LiMnPO4, and the two forms may co-exist in the actual LiFexMn1-xPO4 materials. The calculation manifests that the lithiated/delithiated potentials of LiFexMn1-xPO4 solid solutions vary via the Mn/Fe ratio and the spatial arrangements of the transition metal ions, and the result is used to explain the shape of capacity-voltage curves. Experimentally, we have synthesized the LiFexMn1-xPO4 materials by solid-phase reaction method. The existence of the LiFexMn1-xPO4 solid solution is thought to be responsible for the appearance of additional capacity-voltage plateau observed in the experiment.

Effect of boron/nitrogen co-doping on transport properties of C60 molecular devices

By using nonequilibrium Green＇s function method and first-principles calculations, the electronic transport properties of doped C60 molecular devices were investigated. It is revealed that the C60 molecular devices show the metal behavior due to the interaction between the C60 molecule and the metal electrode. The current-voltage curve displays a linear behavior at low bias, and the currents have the relation of MI〉M3〉M4〉M2 when the bias voltage is lower than 0.6 V. Electronic transport properties are affected greatly by the doped atoms. Negative differential resistance is found in a certain bias range for C60 and C58BN molecular devices, but cannot be observed in C59B and C59N molecular devices. These unconventional effects can be used to design novel nanoelectronic devices.

浅谈SATWE软件在结构计算中注意的问题

在结构计算中，SATWE软件的运用非常广泛，而设计过程中各参数的选取对整体结构的受力分析起着关键作用。本文分析了结构整体计算中SATWE参数的合理选取及其计算结果的合理性判断，只有这样才能设计出合理的结构，确保建筑物的工程质量。

Synthesis, characterization, and theoretical analysis of three new nonlinear optical materials K7MRE2B15O30（M= Ca and Ba, RE= La and Bi）

Three new complex borate compounds K7CaBi2B15O30, K7CaLa2B15 O30 and K7BaBi2B15O30 have been synthesized by the high-temperature solution method.K7CaLa2B15O30and K7CaBi2B15O30crystallize in the chiral trigonal space group R32, while K7BaBi2B15O30 crystallizes in the noncentrosymmetric orthorhombic polar space group Pca21. All of the title compounds have similar three-dimensional crystal structures, which are composed of isolated B5 O10 groups and LaO6 or BiO6 octahedra, and K^+, Ca^2+, and Ba^2+ cations fill into the cavities to keep charge balance. Based on our research, in the system of K7 MIIRE2 B15O30(MII= Ca, Sr,Ba, Zn, Cd, Pb, K/RE0.5;RE = Sc, Y, La, Gd, Lu, Bi),K7BaBi2B15O30 is unique and crystallizes in a different space group, which enriches the structural chemistry of borate.Detailed structural analyses indicate that the structural variation is due to the difference in size and coordination number of the alkaline-earth metal cations. Besides, UV-Vis-NIR spectroscopy analysis and the second-harmonic generation(SHG) measurement on the powder samples show that K7CaBi2B15O30 exhibits a UV cutoff edge(about 282 nm) and a moderate SHG response(about 0.6 × KDP). In addition,thermal analysis and infrared spectroscopy were also presented. To better understand the structure-property relationships of the title compounds, the first-principles calculations have been performed.

结合高铁中间停靠站探讨单层空旷房屋抗震设计

高铁是国家重点投资的铁路建设项目,沿线设有大小车站很多个。本文主要结合中间停靠站(小型规模车站),探讨小型铁路车站的基本设计思路;同时结合车站结构形式,对单层空旷房屋的设计进行分析研究。

Lattice Dynamics Study of Magnesium Chalcogenides

First-principles calculations,which are based on the plane-wave pseudopotential approach to density functional perturbation theory within the local density approximation,have been performed to investigate the structural,lattice dynamical and thermodynamic properties of zinc blende(B3) structure magnesium chalcogenides:MgS,MgSe and MgTe.The results of ground state parameters and phonon dispersion are compared and agree well with the experimental data available and other calculations.We obtain the change of Born effective charge and LO-TO splitting under hydrostatic pressure.Finally,by the calculations of phonon frequencies,some thermodynamic properties such as the entropy,heat capacity,internal energy,and free energy are also successfully obtained.

Stabilization of S_(3)O_(4) at high pressure:implications for the sulfur-excess paradox

The amount of sulfur in SO2 discharged in volcanic eruptions exceeds that available for degassing from the erupted magma.This geological conun drum,known as the"sulfur excess",has been the subject of considerable interests but remains an open question.Here,in a systematic computational investigation of sulfur-oxygen compounds under pressure,a hitherto unknown S_(3)O_(4) compound containing a mixture of sulfur oxidation states+11 and+IV is predicted to be stable at pressures above 79 GPa.We speculate that S_(3)O_(4) may be produced via redox reactions involving subducted S-bearing minerals(e.g.,sulfates and sulfides)with iron and goethite under high-pressure conditions of the deep lower mantle,decomposing to SO2 and S at shallow depths.S_(3)O_(4) may thus be a key intermediate in promoting decomposition of sulfates to release SO2,offering an alter native source of excess sulfur released during explosive eruptions.These findings provide a possible resolution of the"excess sulfur degassing"paradox and a viable mechanism for the exchange of S between Earth's surface and the lower mantle in the deep sulfur cycle.