断层泥显微特征研究在桥基稳定性评价中的应用

基于SEM研究了桥基断裂断层泥的原状显微结构和显微构造、石英碎砾的显微构造、表面刻蚀形貌和结构特征 ,并进一步分析和评价了断裂的抗震和抗断关键问题 ,其对系统论证在断裂带上建设特大型过江桥梁工程的稳定性具有重大实际意义 ,并为镇扬大桥工程的合理设计和安全运行提供了地质依据     

Multiscale evaluation of microstructural worthiness based on the physical–analytical matching (PAM) approach

By selecting the appropriate spatial and temporal variables, physical abnormalities at the microscale can be limited to the essentials such that effective analytical solutions can be made available and identified with high resolution TEM and SEM micrographs. A catalogue of physical–analytical pairs can be stored electronically for the evolution of material damage from micro (or nano) up to macroscopic failure. High speed digital processing can organize such information and make forecast on potential failure in the cyberspace. The micro/macro line cracking model is used to illustrate the use of the PAM (physical–analytical matching) technique although it is still at the early stage of development. Three essential parameters describing the inhomogeneity of the material serve as the basis of the approach while specific microstructural details can be accounted for by using the incidental variables as programmed by PAM in the future. Demonstration is made by using the dual scale micro/macro line crack model where closed form asymptotic solution can be obtained from singularity representation. No generality is lost from the line crack configuration. This is analogous to taking the shape of an atom to be spherical since the exact shape is not relevant. The essential quantities are the energy density and characteristic length associated with the equivalent crack length defined with reference to the spatial and temporal variables under consideration.For a macroscopic tensile specimen containing a micro/macrocrack, multiple microcracking patterns are generated. A priori assumptions related to the grain geometries and/or cohesive force laws to create branching will not be made. Instead, values of the essential parameters are selected to obtain multiple minima of the volume energy density functions. These minima are very closely spaced. This implies that the initiation of multiple microcracking is probable even though dynamic effects are not present. This is in contrast to macrocrack branching where the crack velocity had to approach that of the Rayleigh wave speed. The formulation also shows that empirical approach blind folds the details of microscopic and scaling effects. The double singularity line crack model is used to illustrate that different multiple microcracking patterns can be predicted from the volume energy density fracture criterion that has been used extensively for examining the initiation of macrocracking. The criterion relies on identifying the locations of the stationary values of the energy density function with the potential threshold sites dominated by dilatation or distortion without assuming that the two energy density components are the linear sum, a condition invoked in linear elasticity. To reiterate, three essential parameters are defined to describe the non-homogeneous behavior of the material while two incidental variables are used for the double singularity line crack to account for specific microstructural effects. It is the ease with which asymptotic closed form solution can be obtained and identified with observed damage patterns that suggests the possibility to develop the PAM technique in the cyberspace.     

风光储联合的游梁式抽油机自动平衡装置研究

针对游梁式抽油机平衡装置效果不理想的问题,设计了风光储联合供电的抽油机自动平衡装置;该装置由伺服电机驱动平衡块,根据油井工况实时调节其位置,实现抽油机的最佳平衡;针对平衡装置耗电量大的不足,设计了由风光储联合供电的模式,真正实现抽油机节能;最后,对该装置设计了模糊PD自适应控制器,由模糊控制器在线调节PD控制器参数;在实验室试验10 h,该装置可将抽油机平衡度从1.61减小到1.03以内,白天由太阳能电池供电,夜间由蓄电池供电,其电压从12 V降到9.3 V,表明供电系统完全能满足要求。     

The effects of solvent and microwave on the preparation of Magnesium Oxide Precursor

Four methods including hydrothermal method, glycol‐hydrothermal method, microwave‐hydrothermal method and glycol‐microwave‐hydrothermal method were used to prepare magnesium oxide precursor by the reaction of MgSO₄·7H₂O with (NH₄)₂CO₃. The composition, crystallinity, morphology, aspect ratio, yield, functional groups, atom distribution, and interplanar spacing of the sample were investigated by X‐ray diffraction (XRD), Scan Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FT‐IR), and High Resolution Transmission Electron Microscope (HRTEM). The properties of Magnesium Oxide precursor were compared with each other. The results of FT‐IR and XRD showed that the crystals were all nesquehonite. However, it was shown by FT‐IR results that the crystals prepared by glycol‐microwave‐hydrothermal method contained OH⁻ and HCO₃⁻ groups, which indicated that the Mg(OH)(HCO₃)·2H₂O type crystals would be facilitated by this method. The glycol‐hydrothermal method can create high quality Magnesium Oxide precursor with a high degree of crystallinity, high purity, high aspect ratio, smooth surface, and good dispersibility.     

三状态串、并联系统的优化分配方法

给出了单目标、单约束下三状态串联、并联系统中由选取重要度来提高系统可靠度的有效优化模型及算法,并进行了实例验证.     

Students’ coordination of lower and higher dimensional units in the context of constructing and evaluating sums of consecutive whole numbers

This paper examines how three eighth grade students coordinated lower and higher dimensional units (e.g., composite units and pairs) in the context of constructing a formula for evaluating sums of consecutive whole numbers while solving combinatorics problems (e.g., 1 + 2 + ⋯ + 15 = (16 × 15)/2). The data is drawn from the beginning of an 8-month teaching experiment. The findings from the study include: (1) a framework for understanding how students coordinate lower and higher dimensional units; (2) identification of key learning that occurred as students made the transition between solving two kinds of combinatorics problems; and (3) identification of the links between the way students’ coordinated lower and higher dimensional units and their evaluation of sums of consecutive whole numbers. Implications for research and teaching are considered.     

Bifurcation analysis in a diffusive Segel–Jackson model

Bifurcations of spatially nonhomogeneous periodic orbits and steady state solutions are rigorously proved for a reaction–diffusion system modeling predator–prey interaction. The existence of these patterned solutions shows the richness of the spatiotemporal dynamics such as oscillatory behavior and spatial patterns.     

Effect of Oxyethylete Units on Adsorption and Micellization Properties of Novel Benzene Sulfonate Surfactants

The surface tension and fluorescence spectra of sodium octyl-[ω-octyloxy-poly(oxyethylene)]-yl-benzene sulfonates (APE_nBS) aqueous solutions have been investigated by Wilhelmy plate method and intrinsic probe methods, respectively to study the effect of EO units on their properties. It was discovered that the surface performance of these surfactants was greatly outstanding: the values of critical micelle concentration (CMC) reached to be of the order of magnitude of 10^?5 mol/L, the values of surface tension at CMC, γ_CMC, were between 25.79 to 31.02 mN/m, and the effectiveness and efficiency of surface tension reduction were excellent. The introduction of oxyethylene units to the surfactant molecule evidently improved the solubility of APE_nBS. With the increase in EO units, the CMC slightly changed after the first decreased. On the other hand, the surface excess concentration at saturation, Γ _max, decreased after the first increased and γ_CMC increased after the first decreased accordingly. The CMC determined by fluorescence spectra of intrinsic probe method were accorded with the CMC measured by surface tension method. The aggregation number N, characterized by quenching the fluorescence spectra with methyl viologen (MV²⁺) as the extrinsic quencher, gradually decreased first (from 0 to1) and then slightly changed (from 1 to 4) with increasing EO chain length. So we concluded that the appropriate number of EO units was the key factor to get the best physicochemical properties of APE_nBS.     

Synthesis and mesomorphic properties of chiral liquid crystal dimers derived from azobenzene and substituted naphthol

Symmetrical liquid crystal dimers bis{2-alkyl-(S)-(+)-2-(6-[4-4′-decyloxyphenylazo)-benzoyloxy]-2-naphthyl)propinate} have conveniently been designed, synthesised and their mesomorphic properties were investigated. These dimers possess two identical mesogenic units with each of them attached to the terminal end of a flexible spacer (–C _n H_2n ; where n = 6–10). The respective mesogenic unit was made up from a naphthyl ring attached to the alkyloxylated azobenzene via the ester (COO–) bond. The chiral moiety attached to the 6-position of the naphthyl ring possesses a terminal carboxylic group COO– which linked up the mesogenic unit and the spacer. The thermal and optical properties for the ultimate compounds at different temperature were studied explicitly with the aids of differential scanning calorimetry and polarising optical microscopy. All dimers exhibit unambiguously the monotropic nematic and smectic A phases. The homeotropic alignment of the molecules within the anisotropic region was further confirmed through the application of homogeneously treated cell.     

Thermal Decomposition of Plasma-Polymerized Organosilicon Thin Films

Thermal decomposition of plasma-polymerized hexamethyl-cyclotrisilazane (PP-HMCTSN) thin films was studied by using various techniques. Pyrolysis-gas chromatography investigation of thermal decomposition products and IR examination of the polymer films showed that methylsilyl groups present in the monomer were highly susceptible to form disilymethylene and disilyethylene cross-linkages under plasma conditions. A three-stage mechanism of the thermal decomposition found by thermogravimetry proved a great complexity of the thermal reactions which occur during this process and, in turn, provided strong evidence for a very complex structure of plasma polymer. Electron microscopy investigation revealed a marked effect of the thermal decomposition process on the film microstructure. The trend observed in the morphological changes was consistent with kinetics of this process. The high temperature thermal treatment reduced the organic content of polymer film, correspondingly increasing its inorganic character. Films produced with this process were of unusually interesting properties, displaying strong adhesion to metal substrates and high resistance to corrosive agents.