基于泰勒级数展开的低纬度磁异常化极方法研究

为有效解决低纬度地区磁异常资料化极处理过程中存在沿垂直于磁偏角方向放大、拉伸高频干扰等问题,进而提高磁资料解释的精度,在总结前人提出的低纬度磁异常化极方法原理的基础上,对化极转换因子进行改造,提出基于泰勒级数展开的低纬度化极法。经单模型、多模型正演数据验证和实测数据应用分析,该方法在低纬度区域化极结果准确、可靠、精度更高,有效消除磁异常沿垂直于磁偏角方向拉伸的现象。本文提出的方法明显改善了低纬度地区磁异常化极效果。

磁场波数域正则化化极方法及应用

使用磁场波数域正则化化极方法，对干扰严重的中低纬度航磁异常数据化极，能压制磁南北向的条带状干扰，获得稳定结果；对含有较高噪声水平的高精度地面磁测ΔＴ异常化极，不论纬度高低，都能较大程度地压低噪声水平，获得高质量的化极结果。

氢化脉冲极谱法测定尿中微量镍

提出了用脉冲极谱法测定尿中微量镍的方法。本法简便、无需繁琐的样品前处理及特殊处理设备。检测限０．００１μｇ／ｍｌＮｉ２＋，线性范围０－０．１００μｇ／ｍｌ并允许大量离子共存。

模糊综合评价法与极差化法在高校课堂教学质量评价中的比较

目的比较模糊综合评价法和极差化法在高校课堂教学质量评价中差异和优缺点,从而确定较为有效的教学质量评价方法。方法使用经考评且信度较好的高校课堂教学质量学生评价表,对基于层次分析法的模糊综合评价法和极差化法原理进行论述,运用实例分析两种方法的差异和优缺点。结果运用极差化法对某教师的教学质量评价的综合评价结果为优秀(85.500分),而利用基于层次分析法的模糊综合评判综合评价结果为良好(64.818分),经统计分析结果显示,两种方法在高校课堂教学质量评价中存在差异(t=11.197,P<0.0001)。结论基于层次分析法的模糊综合评判法评价教学质量,对评价因素的非线性和模糊性特点综合考虑,科学计算各评价指标的权重值,定性和定量相结合,较为客观地给出教师课堂教学质量的评价,在实际教学质量评价过程中具有重要意义。

Influence of joint spacing and rock characteristics on the toppling stability of cut rock slope through a simplified limit equilibrium method

Toppling failure of rock mass/soil slope is an important geological and environmental problem.Clarifying its failure mechanism under different conditions has great significance in engineering.The toppling failure of a cutting slope occurred in a hydropower station in Kyushu,Japan illustrates that the joint characteristic played a significant role in the occurrence of rock slope tipping failure.Thus,in order to consider the mechanical properties of jointed rock mass and the influence of geometric conditions,a simplified analytical approach based on the limit equilibrium method for modeling the flexural toppling of cut rock slopes is proposed to consider the influence of the mechanical properties and geometry condition of jointed rock mass.The theoretical solution is compared with the numerical solution taking Kyushu Hydropower Station in Japan as one case,and it is found that the theoretical solution obtained by the simplified analysis method is consistent with the numerical analytical solution,thus verifying the accuracy of the simplified method.Meanwhile,the Goodman-Bray approach conventionally used in engineering practice is improved according to the analytical results.The results show that the allowable slope angle may be obtained by the improved Goodman-Bray approach considering the joint spacing,the joint frictional angle and the tensile strength of rock mass together.

Tunneling Electrons Triggered Energy Transfer between Coherently Coupled Donor-Acceptor Molecules

Energy transfer is ubiquitous in natural and artificial lightharvesting systems,and coherent energy transfer,a highly efficient energy transfer process,has been accepted to play a vital role in such systems.However,the energy oscillation of coherent energy transfer is exceedingly difficult to capture because of its evanescence due to the interaction with a thermal environment.Here a microscopic quantum model is used to study the time evolution of electrons triggered energy transfer between coherently coupled donoracceptor molecules in scanning tunneling microscope(STM).A series of topics in the plasmonic nanocavity(PNC)coupled donor-acceptor molecules system are discussed,including resonant and nonresonant coherent energy transfer,dephasing assisted energy transfer,PNC coupling strength dependent energy transfer,Fano resonance of coherently coupled donor-acceptor molecules,and polariton-mediated energy transfer.

Fabrication and photodegradation properties of TiO_2 nanotubes on porous Ti by anodization

Both Ti foil and porous Ti were anodized in 0.5%HF and in ethylene glycol electrolyte containing 0.5%NH4F(mass fraction) separately. The results show that TiO2 nanotubes can be formed on Ti foil by both processes, whereas TiO2 nanotubes can be formed on porous Ti only in the second process. The overhigh current density led to the failure of the formation nanotubes on porous Ti in 0.5%HF electrolyte. TiO2 nanotubes were characterized by SEM and XRD. TiO2 nanotubes on porous Ti were thinner than those on Ti foil. Anatase was formed when TiO2 nanotubes were annealed at 400 °C and fully turned into rutile at 700 °C. To obtain good photodegradation, the optimal heat treatment temperature of TiO2 nanotubes was 450 °C. The porosity of the substrates influenced photodegradation properties. TiO2 nanotubes on porous Ti with 60% porosity had the best photodegradation.

PPP项目城市投资环境综合评价——以15个副省级城市为例

为了促进PPP项目在我国城市基础设施和公共服务领域的顺利推广、提高PPP项目的成功率,在分析PPP项目所需外部投资环境的具体特点的基础上,建立了PPP项目城市投资环境评价体系,运用层次分析法确定了各个指标的权重,并对15个副省级城市的PPP项目投资环境进行了定量评价。研究结果表明:政府公共治理能力是影响PPP项目城市投资的最重要因素,其余依次是制度环境因素、经济发展状况、市场发育程度。

普惠金融发展水平的测度与比较研究

提高普惠金融发展水平是深化金融改革的重要内容。本文从普惠金融的使用性、可得性和质量性三个层次出发,采取极值化处理法与变异系数法相结合的方法,选取20个评价指标,构建分层次普惠金融发展水平指标评价体系,并对各省区普惠金融发展水平进行测度评价。同时,根据普惠金融指标得分分析各区域提高普惠金融发展水平的方向。

Electrocatalytic Oxidation of Saccharides at MoOx/AuNPs Modified Electrode Towards Analytical Application

The MoOx/AuNPs composite film modified glassy carbon electrode was fabricated by electro-depositing simultaneously gold nanoparticles and molybdenum oxides using cyclic voltammetry. The morphology and topography of the MoOx/AuNPs composite were char-acterized by scan electron microscopy and X-ray photoelectron spectroscopy respectively, and the electrocatalytic oxidation of glucose at the MoOx/AuNPs composite film was inves-tigated and analyzed in detail. It was shown that the MoOx/AuNPs composite was of strong electrocatalytic activity towards oxidation of glucose as well as other saccharides, so that an attempt was made for direct voltammetric determination of glucose. Then the positive scan polarization reverse catalytic voltammetry was proposed for the first time. Based on this method, the pure oxidation current was extracted by subtraction of the blank current in the reverse scan. The current sensitivity was enhanced tremendously and the signal to noise ra-tio was improved adequately. The electrocatalytic oxidation of glucose at the MoOx/AuNPs modified electrode was performed in alkaline medium, a wide linear range from 0.01 mmol/L to 4.0 mmol/L of glucose, a higher current sensitivity of 2.35 mA/（mmol/L·cm2）, and a lower limit of detection of 9.01 μmol/L （at signal/noise=3） were achieved. In addition, the electrocatalytic oxidation of other saccharides such as lactose, fructose and sucrose was also evaluated.

Theoretical Study on Stereodynamics of Reactions of N（^2D）＋H2→NH＋H and N（^2D）＋D2→ND＋D

The vector correlations between products and reagents for the title reactions have been calculated by the quasi-classical trajectory method at a collision energy of 21.32 kJ/mol on an accurate potential energy surface of Ho et al. （J. Chem. Phys. 119, 3063 （2003））. The peaks of the product angular distribution are found to be in both backward and forward directions for the two title reactions. The product rotational angular momentum is not only aligned, but also oriented along the negative direction of y-axis. These theoretical results are in good agreement with recent experimental findings for the two title reactions. The isotopic effect is also revealed and primarily attributed to the difference of the mass factor in the two title reactions.

Synthesis of Ni_(0.8)Co_(0.1)Mn_(0.1)(OH)_2 precursor and electrochemical performance of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2 cathode material for lithium batteries

Spherical and homogeneously mixed metal hydroxide Ni0.8Co0.1Mn0.1（OH）2 precursor was successfully synthesized by co-precipitation method in a simple and small vessel with the volume of 1L.The conditions of synthetic process including amount of chelating agent,stirring speed and temperature were studied.LiNi0.8Co0.1Mn0.1O2 samples were obtained by calcinating the precursors.The crystal structure,morphology and electrochemical properties were investigated by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,charge-discharge test,AC impedance and cyclic voltammetry.In the voltage range of 2.8-4.3 V,the initial discharge capacities of LiNi0.8Co0.1Mn0.1O2 at 0.1C and 1C rates were 199 and 170 mA·h/g,respectively.After 80 cycles at 1C,the discharge capacity retention was 92%,suggesting its promising application as the cathode material for Li-ion batteries.

Understanding the effect of elliptical polarization in surface nuclear magnetic resonance method

Currently, surface nuclear magnetic resonance （SNMR） method is the only geophysical method that detects groundwater directly. In this paper, we investigate the effect of elliptical polarization in the perpendicular excitation magnetic field. The effect of elliptical polarization is clearly visible in our ellipticity calculation and it can cause strong distortion to the excitation field in the presence of high subsurface conductivities. By examining the co-rotating and counter-rotating components of the field, we show that elliptical polarization affects transmitting and receiving processes differently and that a clear phase lag exists between transmitter loop and receiver loop. Finally, we derive the response function of coincident loops and calculate proton tip angles, the kernel function and SNMR response curves of a 1D aquifer model. Based on the simulations, we conclude that the elliptical polarization and phase lag can significantly affect SNMR response and it is essential to include elliptical polarization in SNMR modeling and data interpretation.

Effect of heat treatment on corrosion properties of CuAlNi shape memory alloy

The effect of heat treatment on corrosion properties of CuAlNi shape memory alloy was investigated in 0.9% Na Cl solution at p H 7.4 and 37 ℃ by open circuit potential measurements, polarisation techniques, and electrochemical impedance spectroscopy. Investigations were performed on CuAlNi alloy samples in as-cast state and after heat treatment procedure containing annealing at 850, 885 and 920 ℃ followed by water quenching. Electrochemical impedance measurement results indicate that heat treatment of CuAlNi alloy leads to the increase in charge transfer resistance and surface layer resistance and the decrease in values of capacitance of the double and surface layers, indicating higher corrosion resistance compared with the as-cast CuAlNi alloy. The increase in polarisation resistance and the decrease in corrosion current density of heat-treated CuAlNi alloy also suggest beneficial influence of heat treatment on corrosion resistance of CuAlNi alloy. Optical microscopy, SEM/EDX and XRD analysis of samples surface after polarisation measurements show the occurrence of pitting corrosion on the electrode surfaces, with the existence of CuCl2, AlCl3 and Cu2Cl（OH）3 compounds as the surface corrosion products.

Numerical modeling of anisotropy paradoxes in direct current resistivity and time-domain induced polarization methods

Based on an analytical solution for the current point source in an anisotropic half-space,we study the apparent resistivity and apparent chargeability of a transversely isotropic medium with vertical and horizontal axes symmetry,respectively.We then provide a simple derivation of the anisotropy paradoxes in direct current resistivity and time-domain induced polarization methods.Analogous to the mean resistivity,we propose a formulation for deriving the mean polarizability.We also present a three-dimensional finite element algorithm for modeling the direct current resistivity and time-domain induced polarization using an unstructured tetrahedral grid.Finally,we provide the apparent resistivity and apparent chargeability curves of a tilted,transversely isotropic medium with diff erent angles,respectively.The subsequent results illustrate the anisotropy paradoxes of direct current resistivity and time-domain induced polarization.

Interference Alignment in Two-Way Relay Networks via Rank Constraints Rank Minimization

Interference alignment(IA) is one of the promising measures for the multi-user network to manage interference. The rank constraints rank minimization means that interference spans the lowest dimensional subspace and the useful signal spans all available spatial dimensions. In order to improve the performance of two-way relay network, we can use rank constrained rank minimization(RCRM) to solve the IA problem. This paper proposes left reweighted nuclear norm minimization-γalgorithm and selective coupling reweighted nuclear norm minimization algorithm to implement interference alignment in two-way relay networks. The left reweighted nuclear norm minimization-γ algorithm is based on reweighted nuclear norm minimization algorithm and has a novel γ choosing rule. The selective coupling reweighted nuclear norm minimization algorithm weighting methods choose according to singular value of interference matrixes. Simulation results show that the proposed algorithms considerably improve the sum rate performance and achieve the higher average achievable multiplexing gain in two-way relay interference networks.

Quasi-Classical Trajectory Study on O＋＋DH（v=0,j=0）→OD＋＋H Reaction at Different Collision Energy

The quasi-classical trajectory calculations O＋＋DH（v=0,j=0）→OD＋＋H reactions on the RODRIGO potential energy surface have been carried out to study the isotope effect on stereo-dynamics at the collision energies of 1.0, 1.5, 2.0, and 2.5 eV. The distributions of dihedral angle P（~r） and the distributions of P（Or） are discussed. Furthermore, the angular distributions of the product rotational vectors in the form of polar plot in θr and φr are calculated. The differential cross section shows interesting phenomenon that the reaction is dominated by the direct reaction mechanism. Reaction probability and reaction cross section are also calculated. The calculations indicate that the stereo-dynamics properties of the title reactions are sensitive to the collision energy.

Water-promoted One-step Anodic Acetoxylation of Benzene to Phenyl Acetate with High Selectivity

One-step anodic acetoxylation of benzene to phenyl acetate was studied in acetic acid-water solution using a one-compartment electrochemical cell in galvanostatic mode. Compared to the anhydrous system, the addition of water improved the current efficiency for the electrosynthesis of phenyl acetate. The maximum efficiency reached 4.8% with the selectivity of 96% to phenyl acetate when the electrolysis was carried out under the optimal conditions. The investigation also indicated that the concentration of phenyl acetate increased linearly in 12 h and reached 1.07 g/L with the selectivity of 95%. Cyclic voltammetry experiments showed that the adsorption of benzene at Pt anode enhanced by the addition of water was critical to the formation of phenyl acetate. An activated benzene mechanism was proposed for the anodic acytoxylation, and the analysis of gas products demonstrated that Kolbe reaction was the main side reaction.

SIMPLIFIED ANALYSIS METHOD FOR ULTIMATE LOAD CAPACITY OF WEB PLATES OF BOX GIRDERS

The prosperous post buckling load capacity of web plates of box girders can be used.In this article,the post buckling behaviour of web plates of box girders under different loading conditions is theoretically analyzed and on the basis of domestic and overseas design codes of steel structures,the corresponding simplified analysis methods are put forward for the engineering design or code revision.It is proved that the simplified methods are safe,efficient and practicable through the comparison between several results.