混凝土薄壳球形水窖结构的优化设计

分析球形水窖空间结构的应力分布情况并进行几何尺寸优化,避免建设者根据经验来确定球形水窖的厚度、构造及混凝土标号,以节省建窖材料,同时防止应力不足而发生破坏。【方法】利用基于ANSYS平台新开发的窖体有限元分析软件,对实际中窖壁厚度为4和11 cm的混凝土薄壳球形水窖进行空间结构应力分析,同时以水窖耗材量最小为目标函数,以许用应力和变形量为约束条件,对其进行几何尺寸优化。【结果】计算得出窖壁厚度为4和11 cm的水窖最大拉应力分别为1 380.00和447.31 kPa,最大压应力分别为5 153.20和1 896.70 kPa;优化出空窖不利工况下容积为20,30和40 m3的球形水窖窖壁最佳厚度,即栗钙土地区分别为0.051,0.061和0.065m,黄土地区分别为0.050,0.059和0.062 m。【结论】经软件优化计算后的球形水窖结构,既能满足强度和刚度的要求,同时也最大限度地节约了材料用量;利用新开发的窖体结构优化分析软件,能够对球形水窖进行空间应力分析与结构优化,可以作为球形水窖设计软件。

基于行波介电泳原理的微粒操纵系统及实验研究

随着微/纳米器件及传感器制造的发展,需要一种对大量粒子进行有效操纵的方法,在此背景下,本文介绍了利用行波介电泳方法对大量微粒进行定位和传输操纵的实现方法,分析了利用行波电泳进行微粒操纵所需要的条件,介绍了实现行波介电泳微粒操控的实验系统及实验操作过程,并在该实验系统下实现了对聚苯乙烯小球悬浮及水平传输操纵实验。该系统方法和实现技术为液体环境下微/纳粒子的装配和分离提供了一种可行技术。

广西合山固体废弃物制备地质聚合物胶凝材料

Geopolymer gelatinous material was prepared by ferroalloy slag (signed with NKT in laboratory) and circulating fluidization bed slag (CFB slag, signed with NM in laboratory) produced from Heshan city, Guangxi zhuang autonomous region, China. The mechanical properties of the geopolymer made of high content ferroalloy slag can reach the standard of 42.5# portland blastfurnace-slag cement, and it’s processing technology is more simple and not need of mill and burn and will not produce harmful gas. By means of chemical and XRD analyses, it is concluded that NKT is a kind of acidity water-granulated slag with better activation and fit to be activated by alkali activators. Low-cost industrial gypsum (signed with NG in laboratory), analytic reagent oxide(signed with NH in laboratory) and sulfate(signed with NS in laboratory) were selected as alkali activation in the experiment. The results showed NH is a good alkali activator for NKT. Both NH and NG can activate ferroally slag’s activities, but NS can’t alone. The activation effect of superimposing activation of NH and NG excel by separateness. Based on those experiments, optimization compounds were carried out: (1) NKT: NH: NG = 80: 10: 10 and (2) NM: NKT: NS: NG: NH = 10: 70: 2: 8: 10。. The soundness of the test blocks is good by boiling examination. Through XRD, SEM, IR, NMR analyses of geopolymer, the reaction mechanism of geopolymer prepared by alkalescent activating in solid wastes was discussed in the thesis first. It is point out, there is difference in reaction mechanism between traditional geopolymer preparation and the preparation of alkalescent activating solid wastes because NG is a industry product. There is the similar process of depolymerization and reunion of Si-O bond. The latter preparation process generate new subtance but the former doesn’t. In the experiment, we found a performance of NKT that the water requirement of normal consistency of geopolymer reduces with increasing content of NKT. The result shows NKT has some ability to reduce water requirement. The performance is worthy of further research and utilization. Making use of solid wastes to prepare geopolymer, not only can settle environment problem caused by a great deal of dump of NKT, but also settle the shortage of natural resources. Moreover it could take economic, environmental and social benefits and settle thoroughly contradiction in the environment protection and regional economy development and promote circulation economy development.

基于广义Lippmann-Schwinger方程的地震波场模拟算法与应用

In the last several decades, due to the fast development of computer, numerical simulation has been an indispensable tool in scientific research. Numerical simulation methods which based on partial difference operators such as Finite Difference Method (FDM) and Finite Element Method (FEM) have been widely used. However, in the realm of seismology and seismic prospecting, one usually meets with geological models which have piece-wise heterogeneous structures as well as volume heterogeneities between layers, the continuity of displacement and stress across the irregular layers and seismic wave scattering induced by the perturbation of the volume usually bring in error when using conventional methods based on difference operators. The method discussed in this paper is based on elastic theory and integral theory. Seismic wave equation in the frequency domain is transformed into a generalized Lippmann-Schwinger equation, in which the seismic wavefield contributed by the background is expressed by the boundary integral equation and the scattering by the volume heterogeneities is considered. Boundary element-volume integral method based on this equation has advantages of Boundary Element Method (BEM), such as reducing one dimension of the model, explicit use the displacement and stress continuity across irregular interfaces, high precision, satisfying the boundary at infinite, etc. Also, this method could accurately simulate the seismic scattering by the volume heterogeneities. In this paper, the concrete Lippmann-Schwinger equation is specifically given according to the real geological models. Also, the complete coefficients of the non-smooth point for the integral equation are introduced. Because Boundary Element-Volume integral equation method uses fundamental solutions which are singular when the source point and the field are very close，both in the two dimensional and the three dimensional case, the treatment of the singular kernel affects the precision of this method. The method based on integral transform and integration by parts could treat the points on the boundary and inside the domain. It could transform the singular integral into an analytical one both in two dimensional and in three dimensional cases and thus it could eliminate the singularity. In order to analyze the elastic seismic wave scattering due to regional irregular topographies, the analytical solution for problems of this type is discussed and the analytical solution of P waves by multiple canyons is given. For the boundary reflection, the method used here is infinite boundary element absorbing boundary developed by a pervious researcher. The comparison between the analytical solutions and concrete numerical examples validate the efficiency of this method. We thoroughly discussed the sampling frequency in elastic wave simulation and find that, for a general case, three elements per wavelength is sufficient, however, when the problem is too complex, more elements per wavelength are necessary. Also, the seismic response in the frequency domain of the canyons with different types of random heterogeneities is illustrated. We analyzed the model of the random media, the horizontal and vertical correlation length, the standard deviation, and the dimensionless frequency how to affect the seismic wave amplification on the ground, and thus provide a basis for the choice of the parameter of random media during numerical simulation.

胜利油田低渗透砂岩油藏非均质地质建模

Guided by geological theories, the author analyzed factual informations and applied advanced technologies including logging reinterpretation, predicting of fractal-based fracture network system and stochastic modeling to the low permeable sandstone reservoirs in Shengli oilfield. A new technology suitable for precious geological research and 3D heterogeneity modeling was formed through studies of strata precious correlation, relation between tectonic evolution and fractural distribution, the control and modification of reservoirs diagenesis, logging interpretation mathematical model, reservoir heterogeneity, and so on. The main research achievements are as follows: (1) Proposed four categories of low permeable reservoirs, which were preferable, general, unusual and super low permeable reservoir, respectively; (2) Discussed ten geological features of the low permeable reservoirs in Shengli area; (3) Classified turbidite fan of Es_3 member of the Area 3 in Bonan oilfield into nine types of lithological facies, and established the facies sequences and patterns; (4) Recognized that the main diagenesis were compaction, cementation and dissolution, among which the percent compaction was up to 50%~90%; (5) Divided the pore space in ES_3 member reservoir into secondary pores with dissolved carbonate cement and residual intergranular pores strongly compacted and cemented; (6) Established logging interpretation mathematical model guided by facies- control modeling theory; (7) Predicted the fracture distribution in barriers using fractal method; (8) Constructed reservoir structural model by deterministic method and the 3D model of reservoir parameters by stochastic method; (9) Applied permeability magnitudes and directions to describe the fractures' effect on fluid flow, and presented four different fractural configurations and their influence on permeability; (10) Developed 3D modeling technology for the low permeable sandstone reservoirs. The research provided reliable geological foundation for the establishment and modification of development plans in low permeable sandstone reservoirs, improved the development effect and produced more reserves, which provided technical support for the stable and sustained development of Shengli Oilfield.

汉字阅读中的字形、字音、字义及频率效应的研究

Unlike alphabetic languages, Chinese language is ideographical writing system. Each Chinese character is single-syllable and usually has a direct meaning. So Chinese characters are a kind of valuable experimental material used for research on reading and comparisons of the reading mechanism of different language. In this paper, the normal persons and the patients with semantic dementia were respectively scheduled for two parts of experimental studies on the orthographic, phonologic, semantic and frequency effects of reading of Chinese characters. The Stroop-like character-picture interference experimental paradigm was used to investigate the orthographic, phonologic, semantic and frequency effects of Chinese characters on picture naming when they were presented with pictures to normal persons. The results indicated that the orthographic facilitation effect, phonologic facilitation effect, and semantic interference effect occurred at different SOA values. The orthographic and phonologic facilitation effects were independent. It was for the first time shown that the interaction between orthographic variable and semantic variable occurred when the high-frequency Chinese characters were read. Phonologic representation was activated quicker than semantic representation, by comparison of their SOA. Generally, it means that there is reading without meaning in Chinese character among the normal persons. The orthographic, phonologic, semantic, frequency and concrete effects of Chinese characters were further investigated among the dementia patients with DAT(dementia of Alzheimer's type disease) or CVA or both. They all have an impaired semantic memory. The results showed that patients with dementia could read the names of the pictures aloud while they could not name them or match them with a right character correctly. This is reading impairment without meaning in Chinese among the dementia patients. Meanwhile, they had a selective reading impairment and more LARC(a legitimate alternative reading of components) mistakes especially when reading low-frequency irregular, low-frequency inconsistent and abstract Chinese characters. With the patients' semantic impairment developed, their ability to read the pictures names would remain whereas their ability to read low-frequency irregular and low-frequency inconsistency Chinese characters was reduced. These results indicated that low-frequency irregular Chinese characters can be read correctly only when it is supported by their semantic information. Based on the above results of reading without meaning and of reading of low-frequency irregular Chinese characters supported by their semantic information, it is reasonable to suggest that at least two routes are involved in the process of reading Chinese characters. They are direct phonologic route and indirect semantic route; moreover, the two routes are independent.

Long-Term Evolution Of Delayed Ettringite And Gypsum In Portland Cement Mortars Under Sulfate Erosion

The magnitude evolution of ettringite and gypsum in hydrated Portland cement mortars due to sulfate attack was detected by X-ray powder diffraction. The influences of sulfate concentration and water-to-cement ratio on the evolution of ettringite and gypsum were investigated. Experimental results show that the magnitude of ettringite formation in sodium sulfate solution follows a three-stage process, namely, the 'penetration period', 'enhance period of strength', and 'macro-crack period'. The cracking of concrete materials is mainly attributed to the effect of ettringite. The gypsum formations occurred in two stages, the 'latent period' and the 'accelerated period'. The gypsum formation including ettringite formation was relative to the linear expansion of mortars to some extend. Both water-to-cement ratio and sulfate concentration play important roles in the evolution of ettringite and gypsum. (C) 2008 Elsevier Ltd. All rights reserved.