利用积分方程法的各向异性地层频率测深三维模拟

应用一种新的积分方程算法对各向异性地层频率域电磁测深三维问题进行正演模拟.利用范数小于或等于1的修正Green算子得到各向异性地层中的新积分方程,由于满足压缩映射条件,该积分方程在任意参数条件下总是迭代收敛的.提出一种应用迭代法求解新积分方程的迭代初值优化选择方法,并通过具体算例对比说明该方法可使频率域电磁测深三维模拟的计算效率得到有效提高.最后应用所述算法对层状各向异性大地轴向频率测深视电阻率响应进行三维数值模拟,考察分析地层的各向异性对视电阻率响应特征的影响,得到一些重要结论.     

CO吸附和加氢反应过程的原位高压MAS NMR研究

应用原位变温高压MAS核磁共振技术,对比研究了CO在不同Rh基催化剂上的吸附和加氢反应过程. ²⁹Si MAS NMR研究结果表明：Rh基催化剂中加入金属助剂后,载体Silicate-1上的表面硅羟基减少,助剂金属与硅羟基作用锚锭在载体表面.¹³C MAS NMR研究结果表明：当引入CO/H2混合气后,在Rh/Silicate-1催化剂上只能观测到气相CO、线式吸附CO和孪式吸附CO的快速交换信号;而在Rh-Mn/Silicate-1和Rh-Mn-Li/Silicate-1催化剂上,还观测到了倾斜式吸附的CO共振信号,表明助剂Mn或Mn-Li的加入促进了CO的吸附. 随着反应温度升高,CO/H₂在Rh/Silicate-1催化剂上转化生成CO_²,进一步升高温度会有CH₄生成;而CO/H₂在RhMnLi/Silicate-1催化剂上反应活性更高,在较低的温度下就会转化生成CO₂,但未观测到甲烷的生成. ¹H MAS NMR 谱显示,反应后载体Silicate-1上硅羟基的量会减少,表明CO与载体部分表面硅羟基反应生成了CO₂.     

溅射工艺参数对硅薄膜微结构影响的Raman分析

为了解决碳化硅难以进行光学加工的问题,该文采用射频磁控溅射方法,在碳化硅反射镜坯体上沉积与碳化硅具有相近热膨胀系数且易于进行光学加工的硅薄膜。利用拉曼光谱(Raman)对衬底温度、射频功率、衬底偏压等溅射工艺条件对硅膜微结构的影响进行了分析。研究发现：随着衬底温度的升高,薄膜的晶化率先增大后减小;衬底偏压的增加不利于薄膜有序结构的形成;射频功率对薄膜微结构的影响比较复杂,随着功率的升高,薄膜晶粒尺寸减小,晶化率降低,当射频功率进一步升高时,薄膜中有序团簇尺寸和晶化率逐渐升高。但过高的射频功率反而不利于薄膜的晶化。     

Searching for Flavor-Changing Neutral-Current Signals via e＋e-（γγ） →tcht0 in Topcolor-Assisted Technicolor Model

In the context of the top-color-assisted technicolor （TC2） model, the flavor-changing neutral-current （FCNC） interaction induced by the top-higgs （hOt） are predicted at tree level. We study the relevant processes of e＋e-（γγ）→tcht0 at the International Linear Collider （ILC）. It is found that these rare processes production rates can be enhanced significantly in the TC2 model. Especially for the process γγ→tcht0, the total cross section will reach a few fb in the reasonable parameter space. We also calculate the distributions of transverse momenta, pseudo-rapid and invariant mass of the top-higgs. In view of the main decay modes of top-higgs for mho 〈 2mr, we find that there will be several hundreds FCNC events produced at the ILC with annually integral luminosity of 500 fb-1. Due to the clean background, such FCNC signals can possibly be detected at the ILC.     

同位旋效应对中能重离子反应中轻粒子产物的影响

利用同位旋相关的量子分子动力学模型,研究了¹¹²Sn+¹¹²Sn和¹²⁴Sn+¹²⁴Sn两反应系统在不同入射能量、不同碰撞参数、不同势场和不同核子-核子碰撞截面下的粒子发射特征.阐述了发射体系的同位旋对轻粒子产额比的影响.发现轻粒子产额比是同位旋的敏感观测量.另外,还发现中快度区发射的粒子有更高的丰中子程度.同时,轻粒子的比不敏感于核子核子碰撞截面,而敏感于核态方程,这使得从轻粒子比提取同位旋相关的核态方程变成一种可能. 关键词： 同位旋相关的量子分子动力学 同位旋效应 轻粒子产额比     

(2+1)维Broer-Kaup方程的广义dromion解结构

利用推广的齐次平衡方法,首先将(2+1)维Broer-Kaup方程线性化,然后构造出丰富的广义孤子解,包括单孤子解,单曲线孤子解,单dromion解,多dromion解。此方法直接而简单,可推广应用一大类(2+1)维非线性可积方程。     

Phase Transition Behavior of LiCr 0.35 Mn0.65O2 under High Pressure by Electrical Conductivity Measurement

The electrical conductivity of powdered LiCr 0.35 Mn0.65O2 is measured under high pressure up to 26.22 GPa in the temperature range 300-413 K by using a diamond anvil cell. It is found that both conductivity and activation enthalpy change discontinuously at 5.36 GPa and 21.66 GPa. In the pressure range 1.10-5.36 GPa, pressure increases the activation enthalpy and reduces the carrier scattering, which finally leads to the conductivity increase. In the pressure ranges 6.32-21.66 GPa and 22.60-26.22 GPa, the activation enthalpy decreases with pressure increasing, which has a positive contribution to electrical conductivity increase. Two pressure-induced structural phase transitions are found by in-situ x-ray diffraction under high pressure, which results in the discontinuous changes of conductivity and activation enthalpy.     

煤与天然气适度转化的甲醇-动力联产系统

本文开拓性地提出了一个新型煤和天然气综合利用、甲醇和电力联产的能源动力系统。新系统采用了燃料化学能适度转化的方法,煤先和纯氧与蒸汽发生部分气化反应,适度转化成合成气和半焦,碳转化率约为50%;半焦在天然气/水蒸气重整反应器中燃烧,为重整反应提供反应热;将甲醇生产系统与联合循环发电系统有机整合,来自煤和天然气的合成气先用于甲醇生产,未反应合成气用作发电燃料。研究表明在相同产出条件下,多功能系统比分产系统少消耗10%左右的化石燃料。本文工作为煤和天然气综合高效利用提供了新途径。     

Stochastic Four-State Mechanochemical Model of F1-ATPase

F₁-ATPase, a part of ATP synthase, can synthesize and hydrolyze ATP moleculars in which the central γ-subunit rotates inside the α₃β₃ cylinder. Astochastic four-state mechanochemical coupling model of F$_{1}$-ATPase isstudied with the aid of the master equation. In this model, the ATPhydrolysis and synthesis are dependent on ATP, ADP, and Pi concentrations.The effects of ATP concentration, ADP concentration, and the external torqueon the occupation probability of binding-state, the rotation rate and thediffusion coefficient of F₁-ATPase are investigated. Moreover, theresults from this model are compared with experiments. The mechanochemicalmechanism F₁-ATPase is qualitatively explained by the model.     

Wavelet Cross-Spectrum Analysis of Multi-Scale Disturbance Instability and Transition on Sharp Cone Hypersonic Boundary Layer

Experimental measurement of hypersonic boundary layer stability and transition on a sharp cone with a half angle of 5° is carried out at free-coming stream Mach number 6 in a hypersonic wind tunnel. Mean andfluctuation surface-thermal-flux characteristics of the hypersonic boundary layer flow are measured by Pt-thin-film thermocouple temperature sensors installed at 28 stations on the cone surface along longitudinal direction. At hypersonic speeds, the dominant flow instabilities demonstrate that the growth rate of the second mode tends to exceed that of the low-frequency mode. Wavelet-based cross-spectrum technique is introduced to obtain the multi-scale cross-spectral characteristics of the fluctuating signals in thefrequency range of the second mode. Nonlinear interactions both of the second mode disturbance and the first mode disturbance are demonstrated to be dominant instabilities in the initial stage of laminar-turbulence transition for hypersonic shear flow.