多层采动条件下采空区覆岩残余裂隙发育规律的实验研究

采空区残余裂隙的发育情况是采空区充填注浆设计需要考虑的重要因素。本文采用相似材料模拟实验的方法,探讨多层采动条件下采空区覆岩残余裂隙的分布规律和发育程度。研究结果表明：开采结束后采空区残余裂隙在剖面上具有明显的分区性,从采空区两侧到中间可划分为残余裂隙发育区、裂隙压密区和地表张拉裂隙区; 残余裂隙发育区的残余裂隙率一般介于19.54％～45.27％之间,裂隙压密区的残余裂隙率介于9.28％～19.33％之间; 离层裂隙发育高度是受采宽和累计采厚综合影响的结果。研究成果对于老采空区建筑地基的稳定性评价、采空区处治工程范围与深度的确定、注浆孔的合理布置、单孔注浆量的合理计算等都具有重要的理论研究价值和实际指导意义。     

Design and optimization of an arbitrarily segmented traveling wave electrode for an ultrahigh speed electroabsorption modulator

The modulation response of an arbitrarily segmented traveling wave electroabsorption modulator (TW-EAM) with a non-periodic electrode layout is analyzed with an effective approach based on the transmission line theory. An optimization method based on a genetic algorithm is used to optimize the segmented electrode with additional capacitive pads for a TW-EAM. Optimized electrode structures are given for 165 μm-length devices under standard 50 Ω RF termination condition and 210 μm-length devices with smaller integrated resistors. Great enhancement of performances in modulation response is achieved as compared to the periodic design reported previously. The simulation with the parameters extracted from measurement results suggests that a 3 dB-bandwidth over 100 GHz could be achieved. The eye diagram from the simulation demonstrates that such devices would be competent for a 100Gb/s optical network.     

快凝粉末冶金铝合金的力学行为

对快速凝固粉末冶金Ａｌ－Ｆｅ－Ｖ－Ｓｉ铝合金在室温与升温（２５０℃）时的单向拉伸和疲劳断裂行为进行了研究。结果表明,在２５０℃时,合金不仅拉伸延性（面缩和延伸率）明显地降低,而且其疲劳强度和寿命也明显地减小．断口观察表明,无论是单向拉伸还是循环加载其断裂方式相同,即室温断口表现为正断呈杯锥式。在２５０℃时,断口表现为斜断呈剪切式。透射电镜研究表明,这种断裂模式的改变可能与不同的位错－粒子交互作用机制有关。      

GC-MSD法快速测定蔬菜中四种农药残留方法的改进

在农业部标准NY／T761—2004的基础上,对蔬菜中甲胺磷、毒死蜱、对硫磷和氯氰菊酯4种农药残留的测定方法进行了改进。改进后的方法与原方法相比节省溶剂约60％,节省时间约50％。甲胺磷、毒死蜱、对硫磷和氯氰聚酯的加标回收率分别为67．3％～92．5％、95％～105％、91．2％～107．5％和86．2％～106．2％。     

Solutions of CDG Equation and Modified CDG Equation

This article puts forward a new way to find solutions of CDG equation. The main results are:(i) According to the Lax pair of CDG equation, we introduce the modified CDG equation. (ii) An invariance depending on two parameters of M-CDG equation is found. (iii) Some solutions for CDG equation are obtained by using the invariance.     

离心压气机实际气体准三元数值计算

1前言目前，化工用高压离心式压缩机的工质繁多，它们大都为真实气体。针对压缩理想气体而言的流场分析结果，显然不能简单地用来比拟压缩实际气体的流场．在生产和科学研究中，对压气机进行实际气体的性能测试和流场详细测量都比工质使用空气（理想气体）的难度大得多。因此分析比较理想气体和实际气体这两种不同工质的流场，寻找它们之间的内在联系对指导实际气体的设计工作有重要的指导意义。在这方面，文献[1]已做了大量工作，本文采用了一些不同的方法，做了新的尝试。目的是讨论离心式叶轮内理想气体与实际气体流场分析结果之间的差异…     

紫外激光诱导C60与M(CO)6(M=Cr,Mo, W)的配位反应

研究了用紫外激光(355 nm)诱导C_(60)与金属羰基化合物M(CO)_6(M＝Cr；Mo，W)的配位反应，合成了具有C_(4υ)对称性的配位络合物(η~2－C_(60))M(CO)_5，并初步讨论了C_(60)与M(CO)_6反应的动力学过程．     

Solution NMR studies of the A beta(1-40) and A beta(1-42) peptides establish that the Met35 oxidation state affects the mechanism of amyloid formation

The pathogenesis of Alzheimer's disease is characterized by the aggregation and fibrillation of the 40-residue A beta(1-40) and 42-residue A beta(1-42) peptides into amyloid plaques. The structural changes associated with the conversion of monomeric A beta peptide building blocks into multimeric fibrillar beta-strand aggregates remain unknown. Recently, we established that oxidation of the methionine-35 side chain to the sulfoxide (Met35(red) --> Met35(ox)) significantly impedes the rate of aggregation and fibrillation of the A beta peptide. To explore this effect at greater resolution, we carefully compared the (1)H, (15)N, and (13)C NMR chemical shifts of four A beta peptides that had the Met35 reduced or oxidized (A beta(1-40)Met35(red), A beta(1-40)Met35(ox), A beta(1-42)Met35(red), and A beta(1-42)Met35(ox)). With the use of a special disaggregation protocol, the highly aggregation prone A beta peptides could be studied at higher, millimolar concentrations (as required by NMR) in aqueous solution at neutral pH, remaining largely monomeric at 5 degrees C as determined by sedimentation equilibrium studies. The NOE, amide-NH temperature coefficients, and chemical shift indices of the (1)H alpha, (13)C alpha, and (13)C beta established that the four peptides are largely random, extended chain structures, with the Met35(ox) reducing the propensity for beta-strand structure at two hydrophobic regions (Leu17-Ala21 and Ile31-Val36), and turn- or bendlike structures at Asp7-Glu11 and Phe20-Ser26. Additional NMR studies monitoring changes that occur during aging at 37 degrees C established that, along with a gradual loss of signal/noise, the Met35(ox) significantly hindered upfield chemical shift movements of the 2H NMR signals for the His6, His13, and His14 side chains. Taken together, the present NMR studies demonstrate that the Met35(red) --> Met35(ox) conversion prevents aggregation by reducing both hydrophobic and electrostatic association and that the A beta(1-40)Met35(red), A beta(1-40)Met35(ox), A beta(1-42)Met35(red), and A beta(1-42)Met35(ox) peptides may associate differently, through specific, sharp changes in structure during the initial stages of aggregation.     

Mononuclear, dinuclear, hexanuclear, and one-dimensional polymeric silver complexes having ligand-supported and unsupported argentophilic interactions stabilized by pincer-like 2,6-bis(5-pyrazolyl)pyridine ligands

The mononuclear complexes [Ag(H2L1)(Py)2](NO3) x H2O (1, H2L1 = 2,6-bis(5-methyl-1H-pyrazol-3-yl)pyridine) and [Ag(NO3)(L()] (2, L2 = 2,6-bis(5-methyl-1-isopropyl-1H-pyrazol-3-yl)pyridine), dinuclear complex [Ag2(H2L3)2(HL4)2] (3, H2L3 = 2,6-bis(5-phenyl-1H-pyrazol-3-yl)pyridine, HL4 = 6-(5-phenyl-1H-pyrazolyl-3-yl)picolinate), one-dimensional polymer {[Ag2(H2L1)2](NO3)2 x H2O}(n) (4), and hexanuclear clusters [Ag6(HL1)4](X)2 (X = NO3-, 5 ; BF4-, 6 ; ClO4-, 7) stabilized by pincer-like bispyrazolyl ligands have been prepared and characterized using (1)H NMR spectroscopy, elemental analysis, IR spectroscopy, luminescence spectroscopy and X-ray diffraction. In complex , there is a ligand unsupported Ag-Ag bond between the two silver atoms. Complex displays a one-dimensional polymer consisting of an infinite Ag-Ag chain and every two adjacent silver ions are bridged by an H2L1 ligand. Complexes and have the same Ag6 cores in which six silver atoms are held together by four HL1 and five Ag-Ag bonds, while complex was held together by six Ag-Ag bonds. The silver-silver distances in these complexes are found in the range of 2.874(1)-3.333(2) A for ligand supported, and 3.040(1) A for ligand unsupported Ag-Ag bonds, respectively. Complexes 3-7 are strongly luminescent due to either intraligand or metal-ligand charge transfer processes.