Measurements of saturated basic and acidic rock electrical conductivities at lower crustal temperatures and high pressures

Abstract

Laboratory measurements of the electrical conductivity of brine saturated acidic and metabasic rocks were done at confining pressures up to 0.2 GPa, high pore pressures and temperatures of 900°C. Acidic rocks showed conductivities insufficient to explain the lower crustal high conductivity layer. Basic rocks, however, showed conductivities consistent with the high conductivity layer at those temperatures that the layer is thought to possess.     

Pressure-volume relations for Zn,Cd, Ga,In and TI at room temperature to 30 GPa and above

Abstract

The elemental metals Zn, Cd, Ga, In and TI are studied by energy dispersive X-ray diffraction under pressures up to 30 GPa and above. Room temperature equation of state (EOS) data are derived and compared with results of earlier static and dynamic measurements at lower and higher pressures, respectively.     

大功率单脉冲超声信号发生器的设计

为了提高探伤深度,实现混凝土大坝等散射强介质的超声检测,本文提出了一种成本低,小体积,结构简单的大功率单脉冲超声信号发生器,并给出了原理电路设计。所述装置利用控制电容充放电经脉冲变压器产生瞬时高压脉冲的新思路,克服了过去由于信号幅度限制功率上不去的困难。经实验验证该装置与现有的单脉冲信号发生器相比,探伤深度得到了很大提高,可用于混凝土结构构建的超声探伤。     

Dual channel detection–diode array and mass spectroscopy (El or Cl)–in HPLC

Simultaneous recording of UV and mass spectra (electron impact or chemical Ionization) in conventional HPLC is described. The LC eluent is divided into two parts; one is directed into a diode array detector and the other is introduced into the mass spectrometer via a particle beam interface. The analysis of the steroid esters of a pharmaceutical formulation illustrates the possibilities of dual channel (DAD-MS) HPLC detection.     

Two universal equations of state for solids satisfying the limiting condition at high pressure

In this paper it is shown that the relationship of bulk modulus with pressure, B=f(P), should be linear both at low and high-pressure limiting conditions. Because most of present equations of state (EOS) for solids cannot satisfy such linear relationship at high pressure, a new function f(P) is proposed to satisfy the linearity. By integrating the bulk modulus, an EOS with three parameters and satisfying the quantum-statistics limitation is derived. It is shown that the EOS can be reduced to two-parameter EOS approximately satisfying the limiting condition. By applying the two EOSs and other three typical EOSs to 50 materials, it is concluded that for materials at low and middle-pressure regimes, the limiting condition does not operate, the Baonza EOS gives the best results, but it cannot provide analytic expression for cohesive energy. The Vinet and our second EOSs are slightly inferior, both EOSs can provide analytic expression for cohesive energy, and for materials at high-pressure regimes our second EOS gives the best results. The Holzapfel and our first EOSs give the worst results, although they strictly satisfy the limiting condition. For practical applications, the limiting condition is not important because it only operates as V→0.     

Collective dynamics of supercritical water

Inelastic X-ray scattering experiments on sub- and supercritical water were performed to investigate collective dynamics of this unique solvent. Analysis within a generalized Langevin formalism shows that the positive dispersion of the sound velocity, as compared to the hydrodynamic value, first decreases (1.0<ρ<0.8 g cm⁻³) at all measured momentum transfers (1.3-10.7 nm⁻¹), and then increases (0.7<ρ<0.26 g cm⁻³) again only at higher momentum transfers. We suggest the initial decrease is due to approaching the percolation limit in the number of hydrogen bonds, and the subsequent increase is due to the formation of rigid dimers in sub- and supercritical water.     

HETEROAROMATIC POLYMERS—HIGH TEMPERATURE POLYPYRROLONES DERIVED FROM 2,6-BIS(3'''',4''''-DIAMINOPHENYL)-4-BIPHENYLPYRIDINE AND VARIOUS AROMATIC DIANHYDRIDES

A new type of aromatic tetraamine containing biphenyl moiety in the side chain was synthesized via a modified Chichibabin's reaction.3-Nitro-4-acetamidoacetophenone was reacted with 4-phenyl benzaldehyde in the presence of ammonium acetate to obtain 2,6-bis(3',4'-diaminophenyl)-4-biphenyl pyridine(DPPA).A series of polypyrrolones(PPys) were prepared using tetraamine and various aromatic dianhydrides via a two-step cyclization procedure.All the PPys show excellent high temperature stabilities with the initial decomposition temperatures of 530-549℃ and residual weight ratio of 49%-80% at 750℃ in nitrogen.The polymers exhibit no apparent glass transition temperatures(T_gs)except PPy-1 (T_g=327℃),which is derived from tetraamine DPPA and 2,2-bis[4-(3',4'-dicarboxyphenoxy)-phenyl]propane dianhydride (BPADA).In addition,the polymers have acceptable mechanical properties with the tensile strength of 65-94 MPa.The PPy films show excellent hydrolysis-resistance in alkaline aqueous medium and could maintain most of the properties even after boiling in 10% aqueous sodium hydroxide solution for a week.     

On the origin of the Epps effect

The Epps effect, the decrease of correlations between stock returns for short time windows, was traced back to the trading asynchronicity and to the occasional lead-lag relation between the prices. We study pairs of stocks where the latter is negligible and confirm the importance of asynchronicity but point out that alone these aspects are insufficient to give account for the whole effect.     

变系数情形下Criss-Cross三角形线性元的渐近展式与超收敛

本文讨论了二阶椭圆方程变系数情形下Criss-Cross三角形线性元的超收敛性质,得到了有限元的渐进展式、外推及高精度组合公式等结果.     

高能物理新进展

叙述了近年来高能物理研究取得的新进展，如顶夸克的发现、三代夸克的实验证据、轻子普适性的实验检验．文章还对国际高能物理发展的趋势及中国高能物理的计划进行了介绍．