基于广义正交多项式迭积微分算子的地震波场数值模拟研究

Seismic Numerical Modeling is one of bases of the Exploratory Seismology and Academic Seismology, also is a research field in great demand. Essence of seismic numerical modeling is to assume that structure and parameters of the underground media model are known, simulate the wave-field and calculate the numerical seismic record that should be observed. Seismic numerical modeling is not only a means to know the seismic wave-field in complex inhomogeneous media, but also a test to the application effect by all kinds of methods. There are many seismic numerical modeling methods, each method has its own merits and drawbacks. During the forward modeling, the computation precision and the efficiency are two pivotal questions to evaluate the validity and superiority of the method. The target of my dissertation is to find a new method to possibly improve the computation precision and efficiency, and apply the new forward method to modeling the wave-field in the complex inhomogeneous media. Convolutional Forsyte polynomial differentiator (CFPD) approach developed in this dissertation is robust and efficient, it shares some of the advantages of the high precision of generalized orthogonal polynomial and the high speed of the short operator finite-difference. By adjusting the operator length and optimizing the operator coefficient, the method can involve whole and local information of the wave-field. One of main tasks of the dissertation is to develop a creative, generalized and high precision method. The author introduce convolutional Forsyte polynomial differentiator to calculate the spatial derivative of seismic wave equation, and apply the time staggered grid finite-difference which can better meet the high precision of the convolutional differentiator to substitute the conventional finite-difference to calculate the time derivative of seismic wave equation, then creating a new forward method to modeling the wave-field in complex inhomogeneous media. Comparing with Fourier pseudo-spectral method, Chebyshev pseudo-spectral method, staggered- grid finite difference method and finite element method, convolutional Forsyte polynomial differentiator (CFPD) method has many advantages: 1. Comparing with Fourier pseudo-spectral method. Fourier pseudo-spectral method (FPS) is a local operator, its results have Gibbs effects when the media parameters change, then arose great errors. Therefore, Fourier pseudo-spectral method can not deal with special complex and random heterogeneous media. But convolutional Forsyte polynomial differentiator method can cover global and local information. So for complex inhomogeneous media, CFPD is more efficient. 2. Comparing with staggered-grid high-order finite-difference method, CFPD takes less dots than FD at single wave length, and the number does not increase with the widening of the studying area. 3. Comparing with Chebyshev pseudo-spectral method (CPS). The calculation region of Chebyshev pseudo-spectral method is fixed in , under the condition of unchangeable precision, the augmentation of calculation is unacceptable. Thus Chebyshev pseudo-spectral method is inapplicable to large area. CFPD method is more applicable to large area. 4. Comparing with finite element method (FE), CFPD can use lager grids. The other task of this dissertation is to study 2.5 dimension (2.5D) seismic wave-field. The author reviews the development and present situation of 2.5D problem, expatiates the essentiality of studying the 2.5D problem, apply CFPD method to simulate the seismic wave-field in 2.5D inhomogeneous media. The results indicate that 2.5D numerical modeling is efficient to simulate one of the sections of 3D media, 2.5D calculation is much less time-consuming than 3D calculation, and the wave dispersion of 2.5D modeling is obviously less than that of 3D modeling. Question on applying time staggered-grid convolutional differentiator based on CFPD to modeling 2.5D complex inhomogeneous media was not studied by any geophysicists before, it is a fire-new creation absolutely. The theory and practices prove that the new method can efficiently model the seismic wave-field in complex media. Proposing and developing this new method can provide more choices to study the seismic wave-field modeling, seismic wave migration, seismic inversion, and seismic wave imaging.

池塘养殖环境下滇池金线鲃仔稚鱼的食性转化与生长

下载PDF阅读器2008年3月-2009年3月,把35 000尾滇池金线鲃(Sinocyclocheilus grahami)仔稚鱼分别饲养于3个池塘进行对比饲养研究.密度分别是:P1为208尾/m3;P2为167尾/m3;P3为41尾/m3.饲养期间采用相同的管理措施.每天数据收集采用:在仔鱼孵化后的5～16d的每天8:00和18:00从每个育苗池中捞取5～8尾仔鱼进行测量分析.仔鱼开口30d后,每月从培育池各捞取15尾,测量全长和体重.研究发现,滇池金线鲃仔鱼的开口时间为孵化后的5 d,混合营养期3～5d,这与初孵的演池金线鲃仔鱼的全长和卵黄囊较大有关.在容易造成仔鱼大量死亡的混合营养期,通过采用浆状物-轮虫-人工混合饲料的方式,大幅度提高了滇池金线鲃仔稚鱼的存活率,孵化一年后的滇池会线鲃稚鱼存活率可达82.7%.经过一周年的饲养,滇池金线鲃稚鱼的体重由(0.027±0.01)g(0.003～1.22)增长到(8.83±0.54)g (3.7～16.7),月均增重为0.73 g;全长由(15.8±0.30)mm (11.5～20.0)增长到(91.6±1.67)mm (75.0～16.0),全长月均增长6.32 mm.滇池金线鲃稚鱼全年全长的增长呈线性相关,y=9.82+7.05month(R2=0.9891);全年体重的增长呈指数关系,y=0.0158month2.54(R2=0.9939).

亚硝化细菌的筛选及培养条件的研究

从活性污泥中分离出16株亚硝化细菌,筛选出亚硝酸盐氮积累速率较高的两株菌Y8和Y16,初步鉴定Y8菌株为亚硝化球菌(Nitrosococcns.sp),Y16菌株为亚硝化单胞菌(Nitrosomonas.sp),并对其生长曲线进行了测定。通过氨氮去除率或亚硝酸盐氮的质量浓度来验证亚硝化细菌的活性,考察了生成的亚硝酸盐氮的质量浓度与培养时间的关系、亚硝化细菌的活性与培养温度的关系、亚硝化细菌的活性与培养基pH的关系。Y8和Y16菌株在30℃、培养基pH为7.5、130r/min的条件下振荡培养5d,氨氮去除率分别为81.12%,75.36%。

Eu~(2+),Dy~(3+)共掺杂硼铝锶长余辉玻璃陶瓷

首次介绍了一种新型长余辉材料 :Eu2 + ,Dy3 + 共掺杂硼铝锶长余辉玻璃陶瓷 ,该玻璃陶瓷用紫外灯、日光、荧光灯均可激发 ,发射黄绿色余辉 ,余辉的发射峰位于 5 16nm ,来自于Eu2 + 的 5d→ 8S7/ 2 跃迁。用12 0 0 0lx的荧光灯激发样品 2 0分钟 ,停止激发后 10秒时 ,该玻璃陶瓷的余辉亮度为 3 5 3cd/m2 ,色坐标为 :x =0 2 84 2 ,y =0 5 772 ;停止激发后 5小时 5 5分钟 ,该玻璃陶瓷的余辉亮度为 0 0 1cd/m2 ;停止激发 30小时后 ,余辉在黑暗中仍肉眼可见。文中对该玻璃陶瓷的相关性质进行了表征 ,并提出了可能的长余辉机理

Simultaneous three-photon absorption induced ultraviolet upconversion in Pr3+:Y2SiO5 crystal by femtosecond laser irradiation

Near-infrared to ultraviolet upconversion luminescence was observed in the Pr3+ :Y2SiO5 crystal with 120 fs, 800 mn infrared laser irradiation. The observed emissions at around 270 nm and 305 nm could be assigned to 5d -> 4f transitions of Pr3+ ions. The relationship between the upconversion luminescence intensity and the pump power of the femtosecond laser reveals that the UV emission belongs to simultaneous three-photon absorption induced upconversion luminescence. (c) 2007 Elsevier B.V. All rights reserved.

Study of alpha-, beta- and gamma-cyclodextrin/C-60 supramolecular complexes: Influence of the cavity dimension toward the host-guest complexes

Herein we report the spectroscopic, electrochemical, TEM and DLS characterizations Of C-60 supramolecular inclusion complexes with alpha-, beta- and gamma-cyclodextrins prepared using anionic C-60. The results indicate that the cyclodextrin itself has little effect on the encapsulated C-60 or on the properties of the inclusion complex. Instead, the cyclodextrin has a significant influence on the aggregation behavior of individual complex in aqueous solution, which in turn affects the property of the supramolecular complex of cyclodextrin and C-60 greatly, As the cavity dimension of cyclodextrin becomes smaller as it changes from gamma-CD to beta-CD, and finally to alpha-CD, it is observed that more aggregation occurs for the corresponding inclusion complex in aqueous solution.

Calculation of electrostatic energy H-e(fd) on 4f(N-1)5d configurations for heavy lanthanide ions

For the 4f(N-1)5d configuration the Coulomb interaction between f and d electrons was parameterized by F-k(fd) with K = 2, 4, and G(K)(fd) with K = 1, 3, 5. The spin-orbit interaction for 4f and 5d electrons can be parameterized by xi (f) and xi (d) respectively, which can be compounded into one lambda : lambda = axi (f) + bxi (d), where a and b are the corresponding coefficients. The energy expressions of H-e(fd) of the chief low-energy levels of 4f(N-) (1)5d configuration for heavy lanthanide ions were calculated and the corresponding spin-orbit parameters lambda were also given in LS coupling, which are profitable in analyzing the spectra of the heavy lanthanide ions.

Calculation of the electrostatic energy H-e(fd) on 4f(N-1)5d configuration of lanthanide ions

In LS coupling, the energy expressions of H-e(fd) of the chief low-energy levels of 4f(N-15)d (n < 9) configuration ions are calculated. H-e(fd) can be parameterized with F-K (k=2,4) and G(K)(k=1,3,5). f(k) and g(k), which are coefficients, times the corresponding parameter FK and GK leads to the energy expressions of H-e(fd).

π-烯丙基稀土配合物的合成、结构及其催化烯烃聚合反应机理的研究——Ⅱ.LiY(π-C_3H_5)_4·2.5D催化异戊二烯聚合反应机理的研究

在稀土配位共轭双烯烃聚合反应机理的研究中,一般认为按π-烯丙基机理进行,但迄今为止尚缺乏足够的实验证据。我们曾用~1H-NMR、一维~(13)C-NMR和二维~(13)C-NMR系统地研究了(CF_3COO)_2LnCl·EtoH-(i-Bu)_2AIH-共轭双烯烃(Ln=La、Pr、Nd、Sm、Tb、Ho、Sc和Y)均相聚合体系的聚合机理,提出了η~4-共轭双烯(顺式-反式-)和η~3-烯丙基(同式-对式-)机理。但由于广烯丙基稀土配合物稳定性差,难于合成,加之聚合体系中很难直接分离出π-烯丙基稀土配合物活性体,为此,至今尚未能用模型π-烯丙基稀土配合物对上述机理进行研究。我们已合成一系列π-烯丙基稀土配合物LiLn

3-5岁幼儿认知灵活性的发展

To test preschoolers’ development of cognitive flexibility--an ability to solve a problem in one way and to then switch solution strategies, and the mechanism involved in the development, 3-5-year-olds are asked to perform switching tasks in which the experimenter manipulates the way the stimuli are presented: consecutive or simultaneous; the way the switching happens: between dimensions or within a dimension; the conceptual domains involved: shape, color, number and direction; the specific labels used. The main results of this work are presented below: (1) 3-5-year-olds’ cognitive flexibility develops with age, yet its development is not of the same speed in extra-dimensional switch tasks and inter-dimensional reversal tasks. 3-year-olds manifest some cognitive flexibility, but their performance is significantly worse than that of 4- and 5-year-olds. For the 3-year-olds, in reversal tasks, although 80% of the children passed the post-switch phrase in color task; less then 60% children passed the post-switch phrase in shape, number and direction tasks. In extra-dimensional tasks, 3-year-olds performance is worse than that in the reversal tasks. Less than 50% of the children passed the tasks. Children’s cognitive flexibility develops fast from 3-year-olds to 4-year-olds. Both 4-year-olds and 5-year-olds demonstrate high flexibility without significant difference between them. (2) Children’s flexibility in the conceptual domains of shape, color, number and direction follows different developing patterns. In inter-dimensional reversal tasks, 3-year-olds’ performance is not the same in the 4 conceptual domains, but the difference among the domains is insignificant in 4-and-5-year-olds. In extra-dimensional switching tasks, children’s performance on the 4 domain tasks is significantly different from one another in 3-, 4-, and 5-year-olds. (3) The way the stimuli are presented affects children’s development of cognitive flexibility. In inter-dimensional reversal tasks, 3-year-olds’ performance in consecutive presentation is significantly better than that in simultaneous presentation. 4- and 5-year-olds’ performance in the 2 presentations is not significantly different from each other. In extra-dimensional switch tasks, 3-, 4-, and 5-year-olds’ performance in the consecutive presentation is not significantly better than that in the simultaneous presentation (4) 3-, 4-, and 5-year-olds’ self-issued labeling aids their performance on the switching tasks. Children’ performance in the labeling condition is significantly better than that of no labeling. (5) 3-5-year-olds’ cognitive flexibility is highly correlated with their working memory and inhibition. Children’ development of cognitive flexibility is a process that involves activation of working memory and inhibition, in which the complexity of the task also plays a role.