A novel video opto-mechanical (VOM) device for studying the effect of stretching speed on the optical and structural properties of fibers

Using a novel video opto-mechanical (VOM) device, the effect of stretching speed on the optical and structural properties of polypropylene (PP) fibers during the dynamic stretching process is studied. The objective of the present study is to correlate the optical and mechanical properties of PP fibers with the speed of stretching using the multiple-beam Fizeau fringes system. The skeletonization of the multiple-beam Fizeau fringes are determined automatically by using one-dimension Fourier transform method. The stepper motor is adjusted in order to stretch the fibers continuously with constant and uniform speed until breaking of the fiber. The refractive indices, birefringence, transverse sectional area and the orientation function of PP fibers are studied as a function of the draw ratio at different speeds of stretching. An empirical formula is given to correlate the birefringence of PP fiber and both the draw ratio and the speed of stretching. Stretching process of PP with low speed (slow stretching) is recommended to overcome the necking deformation along the fiber. The VOM device could be used to measure the yield strain. The draw ratio-stretching speed superposition is discussed with some details. Microinterferograms are given for illustration.     

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Thermal diffusivity of reduced activation ferritic/martensitic (RAFM) steel CLF-1 has been determined by the modified photoacoustic piezoelectric (PAPE) technique. Firstly, the modified PAPE theoretical model is introduced and the experimental condition with high measurement precision are identified; Secondly, the experimental system is set up and calibrated by investigating the thermal diffusivity of nickel; Finally, the thermal diffusivity of RAFM steel CLF-1 is measured by the modified PAPE method. The results show that the RAFM steel CLF-1 has good thermal diffusion properties and is a fusion reactor structural material with excellent heat conductivity. The modified PAPE technique can determine the thermal diffusivity of RAFM steel CLF-1effectively, and provides an effective way to investigate the thermal-physical property of fusion reactor structural material.     

黑米花色苷酰化修饰红外光谱分析

黑米花色苷易受外部环境影响发生降解致使局部分子结构破坏而使营养价值和保健功能有所下降。利用有机酸提供酰基对黑米花色苷进行修饰来提高花色苷结构的稳定性。利用红外光谱分析经咖啡酸酰化修饰黑米花色苷的结构变化。结果表明：黑米花色苷酰化修饰前后于官能团区3 650~3 200和1 680~1 620 cm-1处均有吸收峰，且其于指纹区1 282.68和1 277.51 cm-1处出现酚羟基吸收峰，于1 056.07和1 054.03 cm-1处出现醇羟基吸收峰，719.90和719.71 cm-1处出现苯环上C-H面外弯曲振动吸收峰。由此可见，黑米花色苷酰化修饰后主要结构框架仍为花色苷的芳环结构。此外，黑米花色苷酰化修饰前后于1 900~1 650 cm-1间1 714.28和1 728.13 cm-1处均出现共轭羰基的特征吸收峰，对应于可直接连接在苯环上的α-羰基结构，由此说明黑米花色苷结构中存在着酰基基团。黑米花色苷经酰化修饰后红外图谱于1 517.20 cm-1处出现新吸收峰，其正好处于1 800~900 cm-1双键(不含氢)伸缩振动区，指纹区876.65 cm-1处亦出现了苯环上的C-H面外弯曲振动吸收峰。与之相呼应在经二阶导数处理后红外光谱图中在2 500～2 000 cm-1间出现了新的波动，此波段为累积双键伸缩振动区，而官能团区3 650~3 200 cm-1间3 370.20 cm-1处的吸收峰正好处于多分子缔合区。由此可见，在咖啡酸作为酰基供体，酰化修饰黑米花色苷时由于分子间的重新缔合于结构中引入了新的酰基基团而呈现出一种双酰化的空间结构。黑米花色苷酰化结构中有机酸与糖链相连，将有机酸置于2-苯基苯并吡喃骨架的表面，这种堆积作用模式可以较好地抵抗水的亲核攻击和其他降解反应进而提高黑米花色苷结构的稳定性。     

Glassy aging dynamics

We present time-dependent dielectric loss data for various glass formers below the glass temperature. The observed aging dynamics is described using a modified Kohlrausch-Williams-Watts law taking into account the variation of the relaxation time during aging. It leads to values for the aging relaxation time and stretching exponent, fully consistent with the results from equilibrium measurements performed at higher temperatures. Irrespective of the dynamic process prevailing in the investigated frequency region, the aging dynamics is always determined by the structural relaxation process.     

Study of the Anisotropic Elastoplastic Properties of β-Ga<Subscript>2</Subscript>O<Subscript>3</Subscript> Films Synthesized on SiC/Si Substrates

The structural and mechanical properties of gallium oxide films grown on silicon crystallographic planes (001), (011), and (111) with a buffer layer of silicon carbide are investigated. Nanoindentation was used to study the elastoplastic properties of gallium oxide and also to determine the elastic recovery parameter of the films under study. The tensile strength, hardness, elasticity tensor, compliance tensor, Young’s modulus, Poisson’s ratio, and other characteristics of gallium oxide were calculated using quantum chemistry methods. It was found that the gallium oxide crystal is auxetic because, for some stretching directions, the Poisson’s ratio takes on negative values. The calculated values correspond quantitatively to the experimental data. It is concluded that the elastoplastic properties of gallium oxide films approximately correspond to the properties of bulk crystals and that a change in the orientation of the silicon surface leads to a significant change in the orientation of gallium oxide.     

Experimental and computational studies on the solvation of lithium tetrafluorobrate in dimethyl sulfoxide

Solvation structures of the lithium cation and tetrafluorobrate anion in dimethyl sulfoxide (DMSO) were investigated by Raman spectroscopy and ab initio calculations at various salt concentrations. The SO and C S stretching bands were used to monitor the structural change of the solvation shell. It has been shown that the solvation number of Li⁺, calculated by the changes in intensities of the C S asymmetric and symmetric stretching bands, is consistent with the value predicted by ab initio calculations. The wavenumber shift of the C H stretching band is suggested to be the result of the anion solvation and the dissociation of the associated DMSO molecules. Copyright © 2007 John Wiley & Sons, Ltd.     

A Study of Magnetic Diverter Properties in the WISTOR-U Ultimate Torsatron

The WISTOR-U ultimate torsatron design was modeled to determine the effect of various vertical coil configurations particularly with respect to divertor properties. The separatrix and divertor behavior were studied using a modified version of a previously developed code. The divertor properties were studied for various vertical field coil configurations and strengths. The possibility of using structural members for vertical coils and the resultant divertor action around the structural members was investigated. A reduction in area inside the separatrix was observed with deviations from the pure ultimate torsatron base case.     

High Resolution Laser Transient Spectroscopic Technology under Two-Stage Light Gas-Gun Loading Condition and Stability Study of Shocked BenzeneEI北大核心CSCD

The present paper reports the high resolution transient Raman laser testing technology under two-stage light gas-gun loading experiment, and its application to studying the Raman spectroscopy of shocked benzene. In the experiments, the frequency shift of C-C stretching vibration (992 cm(-1)) and C H stretching vibration peak (3 061 cm(-1)) in the low pressure section (less than 8 GPa) varies linearly with the pressure, and the results agree well with reported data in the literature. The structural changes in liquid benzene about 13 GPa were clarified firstly by the Raman spectral technique; the experimental results show that at a pressure of 9.7 GPa, the structural change of liquid benzene has taken place, not reported in the literature about 13 GPa. But the composition in the production is not clear. The measurement system provides an effective means to study the microstructure changes of transparent and translucent material under dynamic loading experiment.     

Analysis of the ir absorption profile of hydrargillite in the region of the valent vibrations of hydroxyl groups

An analysis of the complex absorption profile of hydrargillite in the region of stretching vibrations of the OH bond has been performed with the use of the method of direct fitting of the second-derivative curve. The observed profile is shown to contain an intense broad absorption band masked by eight mutually overlapping relatively narrow bands of structural OH groups of aluminum trihydroxide. The revealed broad absorption band is apparently due to the stretching vibrations of water molecules localized in the trihydroxide structure and the stretching vibrations of structural OH groups interacting with them via the hydrogen bond. An estimation of the basic spectral characteristics of the absorption bands forming the complex profile has been performed. Translated from Zhurnal Prikladnoi Spekroskopii, Vol. 67, No. 3, pp. 306–311, May–June, 2000.     

丹参酮ⅡA和隐丹参酮近红外光谱的2D-COS解析及其在丹参酮提取物近红外模型中应用

采用二维相关光谱（2D-COS）技术,以氘代氯仿为溶剂,解析了丹参酮ⅡA和隐丹参酮标准品的近红外光谱（NIR）。丹参酮ⅡA和隐丹参酮二维相关切片谱在1 600~1 800,1 900~2 230和2 300~2 400 nm处有特征吸收,其中丹参酮ⅡA在1 640和2 140 nm处有不同于隐丹参酮的呋喃环双键一级倍频和组合频吸收,1 696 nm为丹参酮ⅡA和隐丹参酮分子中甲基伸缩振动二级倍频,1 726和1 740 nm处吸收为丹参酮ⅡA和隐丹参酮环己烯亚甲基伸缩振动二级倍频,2 146和2 220 nm为丹参酮ⅡA和隐丹参酮苯环C—C伸缩振动与C—H伸缩振动的组合频,2 300～2 400 nm处一系列峰为丹参酮ⅡA和隐丹参酮甲基伸缩振动与弯曲振动组合频吸收。以丹参酮提取物为载体,以丹参酮ⅡA和隐丹参酮光谱解析特征波段及组合间隔偏最小二乘（SiPLS）筛选特征波段分别建立偏最小二乘（PLS）定量模型,模型的决定系数R2均大于0.9,校正均方根误差（root mean of square error of calibration, RMSEC）和交叉验证均方根误差（RMSECV）,预测均方根误差（RMSEP）均较小。结果表明,2D-COS技术解析特征波段与SiPLS波段筛选所建PLS模型均稳定。2D-COS技术使近红外定量模型更具解释性,可解析出结构差异特征吸收,同一波段可实现结构类似物的同时定量测定。     

Vibro-acoustic behaviors of an elastically restrained double-panel structure with an acoustic cavity of arbitrary boundary impedance

An analytical study on the vibro-acoustic behaviors of a double-panel structure with an acoustic cavity is presented. Unlike the existing studies, a structural–acoustic coupling model of an elastically restrained double-panel structure with an acoustic cavity having arbitrary impedance on sidewalls around the cavity is developed in which the two dimensional (2D) and three dimensional (3D) modified Fourier series are used to represent the displacement of the panels and the sound pressure inside the cavity, respectively. The unknown expansions coefficients are treated as the generalized coordinates and the Rayleigh–Ritz method is employed to determine displacement and sound pressure solutions based on the energy expressions for the coupled structural–acoustic system. The effectiveness and accuracy of the present model is validated by numerical example and comparison with finite element method (FEM) and existing analytical method, with good agreement achieved. The influence of key parameters on the vibro-acoustic behaviors and sound transmission of the double-panel structure is investigated, including: cavity thickness, boundary conditions, sidewall impedance, and the acoustic medium in the cavity.     

修正屏蔽库仑势下二维尘埃等离子体的动力学和结构特性

本文考虑等离子体密度分布变化, 得到了修正屏蔽库仑势的解析解. 数值分析以及分子动力学模拟表明, 在常见实验室参数情况下, 等离子体密度分布变化引起的屏蔽库仑势修正对二维尘埃等离 子体系统的动力学和结构特性影响很小. 在极限参数情况下, 本模型的计算结果表明二维尘埃等离子体系统的扩散能力明显降低, 并且系统组态呈圆形分布. 此外, 本文还研究了实验室常见大小磁场对二维尘埃等离子体系统的影响. 关键词： 修正屏蔽库仑势 二维尘埃等离子体 分子动力学模拟     

水溶液中硫酸根离子的拉曼光谱定量分析

拉曼光谱因其具有无损、非接触以及原位的技术优势被广泛应用于科学研究领域。但是,当前拉曼光谱主要应用于定性研究,即根据拉曼波数偏移进行物质分子的鉴别,相比之下,拉曼光谱定量分析则明显不足。因此,有必要进一步开展拉曼光谱定量方面的研究。根据拉曼光谱原理分析可知,拉曼光谱定量研究应当根据相对强度比进行,也就是在定量化过程中需要选择一个参考系,可以分为内标法和外标法。拉曼光谱定量可以根据被测分子与该参考系的拉曼强度比值进行,通过这个方法可以消除测试条件的影响。对水溶液而言,可将液态水的OH伸缩振动作为内标,进行拉曼光谱定量分析。本文研究了Na₂SO₄-H₂O,K₂SO₄-H₂O以及NaCl-Na₂SO₄-H₂O体系的拉曼光谱特征。通过将水分子的OH伸缩振动（2 750~3 900 cm-1附近）拟合为两个高斯谱峰,并以I_SO2-4/I_W为参数来确定溶液中的硫酸根离子浓度,其中I_SO2-4为硫酸根离子的特征峰强度,I_W为水的两个高斯谱峰强度之和。实验结果表明,水溶液中SO2-₄浓度与拉曼强度比I_SO2-4/I_W之间有较好的线性关系,其中,R2=0.997 73,符合定量要求。据此,本文应用拉曼光谱定量分析,建立了一种相对快速、准确测量水溶液中SO2-₄浓度的方法。     

The Microstructure of Soda-Lime Silicate Glasses Detected by Electron Microscopy

Transmission electron microscopy and selected area electron diffraction performances were used to characterise the microstructure of a multicomponent soda-lime silicate glass, the composition of which corresponds to the miscibility gap in the SiO₂—Na₂O system. It has been stated that phase separation already exists in as prepared specimens, and the Na₂O-rich phase occurs in the form of nearly spherical droplets. The microstructure of these glasses was modified by high-temperature annealing in air and hydrogen, by irradiation with soft X- and gamma-irradiation and by mechanical stretching. In this way the quantity, size, shape and distribution of these particles was changed. A variety of induced changes affects the structure-sensitive properties of commercial soda lime silicate glasses, which can be potentially useful for new applications.     

Influence of Passive Stretching on Inhibition of Disuse Atrophy and Hemodynamics of Rat Soleus Muscle

The purpose of this study was to determine the influence of passive stretching on inhibition of disuse atrophy and hemodynamics among longitudinal regions of the rat soleus muscle. Disuse muscle atrophy was induced by hindlimb suspension for two weeks. Muscle blood flow was evaluated using thallium-201 (²⁰¹Tl) which is a radiotracer that has been reported to be useful to assess blood perfusion in skeletal muscle. Thirty-nine male Wistar rats were divided randomly into 5 groups: control (C: n = 10), a group with hindlimb suspension (HS: n = 7), a group with hindlimb suspension and stretching (ST: n = 7), a group receiving only a single session of stretching after the hindlimb suspension period that was killed just after stretching (HSB: n = 7), and a group receiving only a single session of stretching hindlimb suspension and stretching period that was killed just after stretching (STB: n = 8). From the results of the cross-sectional area (CSA) and the capillary-to-fiber ratio (C/F), muscle atrophy and inhibition of atrophy were shown more in proximal than in distal regions of experimental groups. These results suggest that the alterations of the C/F and CSA were different among muscle regions in experimental groups. These differences may depend on the level of stretching. Moreover, alteration of blood flow resulting from alteration of the mechanical environment had little influence on muscle atrophy or inhibition of atrophy.     

Infrared Spectra of Protiated and Deuterated Lead(II) Saccharinate Monohydrate : Spectra-Structure Correlations

The infrared spectra of protiated and deuterated lead(II) saccharinate monohydrate, Pb(C₇H₄NO₃S)₂·H₂O were studied in the OH, OD, CO and SO₂ stretching regions. The spectral characteristics of the HOH and HOD stretching fundamentals were correlated with the structural data on the geometry of the water molecules. Also correlated were the appearance of the spectrum in the CO stretching region, on the one hand, and the number of non-equivalent carbonyl groups in the structure, on the other. An attempt was made to assign the bands which are mainly due to the antisymmetric and the symmetric SO₂ stretching vibrations.     

Scaling behaviour of polyelectrolytes and polyelectrolyte brushes

Summary Simulation results as well as experimental data indicate that full stretching of flexible polyelectrolytes will not occur under experimentally realizable conditions. Using density-dependent swelling exponents ν(ϕ) as suggested by Stevens and Kremer from the results of a MD simulation study, we present an Alexander-de Gennes-like scaling picture for the behaviour of charged brushes. The brush height is found to become dependent on the grafting density as soon as internal stretching is incomplete. For a particular anchoring technique used in experimental studies the grafting density itself becomes dependent on the chain length. The resulting modified overall chain length dependence of the brush height is discussed. Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994.     

Passive and active interior noise control of box structures using the structural intensity method

This paper presents passive and active vibro-acoustic noise control methods for attenuating the interior noise level in box structures which can be an analogy of cabins of vehicle and aircraft. The structural intensity (SI) approach is adopted to identify the predominant vibration panels and interior noise sources for box structures. In the study, the finite element method is used to determine the structural vibration and structural intensity in the box surfaces. According to structural intensity vectors plot and structural intensity stream lines presentation, the possible effective control positions where the dampers may be attached and the active control forces may act to reduce vibration and interior noise, are identified. From the study, it can be demonstrated that the structural intensity approach and stream line presentation are possible methods for identifying the vibro-acoustic interior noise source and predominant panels which may be modified to reduce the interior noise level. The structural intensity methodology, passive and active noise control results can be extended to the further study of the vibration and interior noise control of actual cabins of vehicles and aircraft.     

Bi系高温氧化物超导体CuO2面内Cu-O键伸缩振动的分析

测试了一系列Ｂｉ系高温氧化物超导体的红外吸收谱，分析了Ｂｉ系超导样品ＣｕＯ２面内Ｃｕ－Ｏ键的伸缩振动与样品超电性的联系。结果表明，ＣｕＯ２面内Ｃｕ－Ｏ伸缩振动吸收峰强度的变化与样品零电阻的变化一致，其原因与微观结构内部声子与载流子的相互作用密切相关。其次，根据分子振动理论，采用简化模型计算了Ｂｉ系超导体ＣｕＯ２面内Ｃｕ－Ｏ振支频率     

Rapid characterization of molecular chemistry,nutrient make‐up and microlocation of internal seed tissue

Wheat differs from corn in biodegradation kinetics and fermentation characteristics. Wheat exhibits a relatively high rate (23% h^?1) and extent (78% DM) of biodegradation, which can lead to metabolic problems such as acidosis and bloat in ruminants. The objective of this study was to rapidly characterize the molecular chemistry of the internal structure of wheat (cv. AC Barrie) and reveal both its structural chemical make‐up and nutrient component matrix by analyzing the intensity and spatial distribution of molecular functional groups within the intact seed using advanced synchrotron‐powered Fourier transform infrared (FTIR) microspectroscopy. The experiment was performed at the U2B station of the National Synchrotron Light Source at Brookhaven National Laboratory, New York, USA. The wheat tissue was imaged systematically from the pericarp, seed coat, aleurone layer and endosperm under the peaks at ～1732 (carbonyl C=O ester), 1515 (aromatic compound of lignin), 1650 (amide I), 1025 (non‐structural CHO), 1550 (amide II), 1246 (cellulosic material), 1160, 1150, 1080, 930, 860 (all CHO), 3350 (OH and NH stretching), 2928 (CH₂ stretching band) and 2885 cm^?1 (CH₃ stretching band). Hierarchical cluster analysis and principal component analysis were applied to analyze the molecular FTIR spectra obtained from the different inherent structures within the intact wheat tissues. The results showed that, with synchrotron‐powered FTIR microspectroscopy, images of the molecular chemistry of wheat could be generated at an ultra‐spatial resolution. The features of aromatic lignin, structural and non‐structural carbohydrates, as well as nutrient make‐up and interactions in the seeds, could be revealed. Both principal component analysis and hierarchical cluster analysis methods are conclusive in showing that they can discriminate and classify the different inherent structures within the seed tissue. The wheat exhibited distinguishable differences in the structural and nutrient make‐up among the pericarp, seed coat, aleurone layer and endosperm. Such information on the molecular chemistry can be used for grain‐breeding programs for selecting a superior variety of wheat targeted for food and feed purposes and for predicting wheat quality and nutritive value in humans and animals. Thus advanced synchrotron‐powered FTIR technology can provide a greater understanding of the plant–animal interface.