大豆（Glycine max (L)Merr.）叶片和非叶器官光合特性探讨

本论文由三部分组成，一、大豆高产品种黑农40与低产品种黑农37不同发育时期叶片光合功能的比较研究。二、大豆非叶器官豆荚的光合特性。三、不同大豆品种叶片和非叶器官光合特性的比较分析。 一、 黑农40和黑农37不同发育时期叶片的光合特性。 以不同产量水平的东北大豆黑农40和对照品种黑农37为试验材料，研究了从幼苗期到衰老期五个不同发育时期叶片光合作用特性的变化。尤其是比较系统地研究了C4途径的表达，并通过相关分析，发现C4途径酶的活性与大豆的光合效率及其产量密切相关。主要研究结果如下： 1．测定不同发育时期大豆叶片净光合速率、DCIP光还原活力和1,5-二磷酸核酮糖羧化酶(RuBPcase)活力，结果表明，黑农40和黑农37叶片净光合速率均在初荚期达到最高值，而且不同发育时期的黑农40叶片光合能力均强于黑农37。 2．随着大豆叶片的发育和衰老，其叶绿素、类胡萝卜素的含量及Chla/b比值有一个逐渐升高，而后降低的过程。在同一发育时期，高产高光效品种黑农40光合色素含量均高于黑农37，有助于黑农40捕获更多的光能供光合作用所利用。 3．叶绿体吸收光谱及四阶导数光谱表明在整个生育期内以初荚期叶片对光能的吸收能力最强;而每一个发育时期黑农40叶片对光能吸收的能力均比黑农37高。荧光动力学参数表明，高产大豆黑农40叶片PSII活性(Fv/Fo)，光化学猝灭系数(qP)及PSII总的光化学量子产量也均高于对照品种黑农37的相应值：而黑农40的非光化学猝灭系数(qN)低于黑农37。说明高产大豆叶片具有与产量潜力相关的较高光能吸收和原初转化能力。通过对叶片及其叶绿体低温(77K)荧光发射光谱特性的分析表明，黑农40叶绿体对两个光系统之间激发能的调节能力优于黑农37。总之，黑农40对光能的吸收、传递和转化能力高于黑农37，从而能为碳同化提供更多能量。 4．通过研究苗期、开花期、初荚期、鼓粒期和衰老期等发育阶段的黑农40和黑农37叶片中磷酸烯醇式丙酮酸羧化酶(PEPCase)、NADP-苹果酸脱氢酶(NADP-MDH)、NADP-苹果酸酶(NADP-ME)、丙酮酸磷酸双激酶(PPDK)等C4途径的关键酶的活性变化，结合同位素14CO2喂饲试验，证明两种大豆叶片均含有C4途径四种关键酶，其原初产物含有有限的有机酸，说明有C4循环存在;而从PEPCase/RuBPcase的比值看，C4途径的酶在黑农40叶片中表达较高。通过相关分析，我们发现Pn与PSII光化学活性，RuBPCase及C4酶活性密切相关。这些结果还暗示有可能通过检测C4途径酶的表达水平及比例，筛选出具有高产潜力的大豆种质。 二、大豆非叶器官豆荚的光合特性。 通过对大豆非叶器官豆荚光合特性的研究，结果表明大豆豆荚的光合能力在鼓粒期达到最高值。通过叶绿体吸收光谱、荧光动力学和低温荧光等测定技术，我们发现鼓粒期的豆荚对光能的吸收、传递和转化有更高的能力;在鼓粒期不同品种的豆荚色素的含量也较高，从而有利于捕获更多的光能，供光合作用利用。DCIP光还原活力的测定结果表明鼓粒期豆荚也具有较高光合能力。 通过对大豆的初荚期、鼓粒期和衰老期豆荚RuBPCase和四种C4途径酶活性的研究，不仅证明非叶器官中有高活性的C4途径酶和存在有限的C4途径，而且鼓粒期豆荚有较高的碳同化效率。 三、不同大豆叶片和非叶器官光合特性的比较分析。 对三种大豆叶片、豆荚、种皮和子叶的色素含量和Chla/b进行测定，利用光谱技术、荧光技术及RuBPCase活性的测定，分析了大豆不同器官的光合特性。试验结果证明，非叶器官具有与叶器官相似的光合性能。与叶片比较，表明在非叶器官中具有非常高的C4酶活性。有利于补偿叶片开始衰老光合作用衰退的不足，因此非叶器官的这些光合特性有助于增加大豆光合产物的积累。

InAs/InP（0.7）Sb（0.3）热电子晶体管的fT及f（max）

于2010-11-23批量导入

连续逻辑"max""min"门的线性度

于2010-11-23批量导入

Nanoadhesion of a Power-Law Graded Elastic Material

The Dugdale-Barenblatt model is used to analyze the adhesion of graded elastic materials at the nanoscale with Young's modulus E varying with depth z according to a power law E = E-0(z/c(0))(k) (0 < k < 1) while Poisson's ratio v remains a constant, where E-0 is a referenced Young's modulus, k is the gradient exponent and c(0) is a characteristic length describing the variation rate of Young's modulus. We show that, when the size of a rigid punch becomes smaller than a critical length, the adhesive interface between the punch and the graded material detaches due to rupture with uniform stresses, rather than by crack propagation with stress concentration. The critical length can be reduced to the one for isotropic elastic materials only if the gradient exponent k vanishes.

Non-modal instabilities of two-dimensional disturbances in plane Couette flow of a power-law fluid

Instabilities of fluid flows have traditionally been investigated by normal mode analysis, i.e. by linearizing the equations of flow and testing for unstable eigenvalues of the linearized problem. However, the results of eigenvalue analysis agree poorly in many cases with experiments, especially for shear flows. In this paper we study the instabilities of two-dimensional Couette flow of a polymeric fluid in the framework of non-modal stability theory rather than normal mode analysis. A power-law model is used to describe the polymeric liquid. We focus on the response to external excitations and initial conditions by examining the pseudospectra structures and the transient energy growths. For both Newtonian and non-Newtonian flows, the results show that there can be a rather large transient growth even though the linear operator of Couette flow has no unstable eigenvalue. The effects of non-Newtonian viscosity on the transient behaviors are examined in this study. The results show that the "shear-thinning/shear-thickening" effect increases/decreases the amplitude of responses to external excitations and initial conditions. (C) 2010 Elsevier B.V. All rights reserved.

Indentation of power law creep solids by self-similar indenters

For creep solids obeying the power law under tension proposed by Tabor, namely sigma = b(epsilon) over dot(m), it has been established through dimensional analysis that for self-similar indenters the load F versus indentation depth h can be expressed as F(t) = bh(2)(t)[(h) over dot(t)/h(t)](m)Pi(alpha) where the dimensionless factor Pi(alpha) depends on material parameters such as m and the indenter geometry. In this article, we show that by generalizing the Tabor power law to the general three dimensional case on the basis of isotropy, this factor can be calculated so that indentation test can be used to determine the material parameters b and m appearing in the original power law. Hence indentation test can replace tension test. This could be a distinct advantage for materials that come in the form of thin films, coatings or otherwise available only in small amounts. To facilitate application values of this constant are given in tabulated form for a range of material parameters. (C) 2010 Elsevier B.V. All rights reserved.

The generalized second law of thermodynamics in generalized gravity theories

We investigate the generalized second law of thermodynamics (GSL) in generalized theories of gravity. We examine the total entropy evolution with time including the horizon entropy, the non-equilibrium entropy production, and the entropy of all matter, field and energy components. We derive a universal condition to protect the generalized second law and study its validity in different gravity theories. In Einstein gravity (even in the phantom-dominated universe with a Schwarzschild black hole), Lovelock gravity and braneworld gravity, we show that the condition to keep the GSL can always be satisfied. In f ( R) gravity and scalar-tensor gravity, the condition to protect the GSL can also hold because the temperature should be positive, gravity is always attractive and the effective Newton constant should be an approximate constant satisfying the experimental bounds.

Power law behavior of the isotope yield distributions in the multifragmentation regime of heavy ion reactions

Isotope yield distributions in the multifragmentation regime were studied with high-quality isotope identification, focusing on the intermediate mass fragments (IMFs) produced in semiviolent collisions. The yields were analyzed within the framework of a modified Fisher model. Using the ratio of the mass-dependent symmetry energy coefficient relative to the temperature, a(sym)/T, extracted in previous work and that of the pairing term, a(p)/T, extracted from this work, and assuming that both reflect secondary decay processes, the experimentally observed isotope yields were corrected for these effects. For a given I = N - Z value, the corrected yields of isotopes relative to the yield of C-12 show a power law distribution Y (N, Z)/Y(C-12) similar to A(-tau) in the mass range 1 <= A <= 30, and the distributions are almost identical for the different reactions studied. The observed power law distributions change systematically when I of the isotopes changes and the extracted tau value decreases from 3.9 to 1.0 as I increases from -1 to 3. These observations are well reproduced by a simple deexcitation model, with which the power law distribution of the primary isotopes is determined to be tau(prim) = 2.4 +/- 0.2, suggesting that the disassembling system at the time of the fragment formation is indeed at, or very near, the critical point.

Exploring the Origin of Power Law Distribution in Single-Molecule Conformation Dynamics: Energy Landscape Perspectives

We explored the origin of power law distribution observed in single-molecule conformational dynamics experiments. By establishing a kinetic master equation approach to study statistically the microscopic state dynamics, we show that the underlying landscape with exponentially distributed density of states leads to power law distribution of kinetics. The exponential density of states emerges when the system becomes glassy and landscape becomes rough with significant trapping.

Multi-color long-lasting phosphorescence in Mn2+-doped ZnO-B2O3-SiO2 glass-ceramics

Multi-color LLP phenomenon was observed in Mn2+-doped ZnO-B2O3-SiO2 glassceramics after the irradiation of a UV lamp at room temperature. Transparent ZnO-B2O3-SiO2 glass emitted reddish LLP while opaque glass-ceramics prepared by the glass sample after heat treatment emitted yellowish or greenish LLP. The change of the phosphorescence is due to the alteration of co-ordination state of Mn2+. The phosphorescence of the samples was seen in the dark with naked eyes even 12 h after the irradiation with a UV lamp (lambda(max) = 254 nm) for 30 min. Based on the approximative t(-1) decay law of the phosphorescence, we suggest that the LLP is attributed to the thermally assisted electron-hole recombination.