共查询到20条相似文献,搜索用时 93 毫秒
1.
Origin用于物理化学实验数据的非线性拟合 总被引:4,自引:0,他引:4
在物理化学实验数据处理中应用Origin软件对数据进行非线性拟合,介绍用Origin求得实验曲线的非线性拟合参数的方法。结果表明,使用该软件能降低数据处理的随意性,减少处理误差,并且快捷方便,使实验结果更合理。 相似文献
2.
3.
4.
尖晶石锂锰氧化物锂离子嵌脱过程的交流阻抗谱研究 总被引:18,自引:1,他引:18
用粉末微电极研究了尖晶石锂锰氧化物在不同嵌锂状态下嵌脱锂过程的交流阻 抗图谱,提出了新的等效电路模型。描述锂离子在固体中扩散的Warburg阻抗与累 积或消耗的嵌入电容在Lix MnO4中的x≤0.5时串联,0.5<x≤1时并联。用提出 的等效电路模型分阶段拟合了实验所得的交流阻抗谱,拟合值与实验值相当吻合, 由拟合结果得到不同电位下锂离子在表面膜中的迁移电阻和电容,界面电荷传递电 阻,双层电容,锂离子在固体中扩散系数和累积或消耗的嵌入电容。 相似文献
5.
基态H2O^ 分子离子是重要的星际反应中间体,用MRCISD/cc-pVTZ先计算H2O^ 势能面,然后拟合成多体势能函数,全域势能面能很好地描述基态H2O^ 的行为,与两条反应通道的实验能变和其构型翻转反应能垒比较,表明计算结果与实验值相符,对计算点完成了力场的多项式拟合,对其振动模式进行了分析。 相似文献
6.
7.
8.
9.
介绍了Origin软件中用户自定义非线性拟合功能的使用方法,并结合实例讨论如何应用非线性拟合对分析化学实验数据进行处理。结果表明,该方法能准确计算实验结果、对实验数据进行评价,同时还可方便得到绘制的图表,应在分析化学实验教学中推广应用。 相似文献
10.
11.
Macroscopic and microscale creep deformations of UHMWPE were investigated by using in situ SAXS.A methodology for the measurement of the local creep deformation of inter-lamellar amorphous phase has been proposed.The local strain of inter-lamellar amorphous phase (εa) and macroscopic strain (εmacro) were evaluated and they were compared to study the relationship between macroscopic and microscale creep deformation of UHMWPE.Both of them exhibit two deformation regions against creep time.The entanglements show a strong impact on both the macroscopic and local inter-lamellar amorphous phase creep behavior and they can be well correlated to the molecular weight between two entanglements estimated from strain-hardening modulus.Compared to the macroscopic creep deformation,local inter-lamellar amorphous layers have a smaller creep deformation.From the local creep measurement,the apparent modulus of inter-lamellar amorphous phase can also be estimated (200 < Ma < 500 MPa).These values are much higher than the Young's modulus of bulk amorphous PE,which can be well explained by the confinement of the lamellar stacks and the enhancement of the amorphous phase with the relatively high concentration of entanglements.This study provides a useful means and quantitative data for achieving the scale transition between the micro and the macro structural levels for the study of viscos-elastic deformation. 相似文献
12.
非晶态半导体硅(α-Si:H)薄膜作为新型的光电子材料,近年来备受关注,发展迅速。但其晶化机理有待深入探索。用分形理论所作的分析表明,在一定条件下,a-Si:H薄膜中形成的微结构具有分形性质。本文计算了分维值,讨论了a-Si:H薄膜结构弛豫(相变)与分形结构形成的关联,和非晶硅薄膜可能的晶化机理。并研究了在高真空中用透射电子显微镜(TEM)及动态方法跟踪观测a-Si:H薄膜原位(in situ)退火过程中发生的晶化现象,获得晶化形貌的显微图像。利用图像处理技术对显微像进行光电转换,A/D转换和数字计算,得到a-Si:H薄膜样品在不同退火条件下,显微象的Sandbox关系曲线。从而获得薄膜中形成不同分形结构的分维。文中给出应用分形理论对非晶态半导体薄膜进行分析的技术细节。 相似文献
13.
A statistical mechanical model is used to analyze literature data regarding the restricted segmental dynamics of a number of crystallized polymers, as observed by means of broadband dielectric spectroscopy. A relationship between well defined physical quantities and the width parameter in the Havriliak–Negami representation of symmetric processes is established. It is found that, for materials crystallized from an isotropic amorphous state, the segmental relaxation process is associated to conformational changes within cooperatively rearranging regions of ~1 nm diameter. In case of chain orientation, the dimension of the rearranging regions along the chain direction increases up to 3–5 nm. It is argued that the average size of the rearranging regions may influence the thickness of the amorphous interlamellar layers in the stacks. It is also found in all cases that, at the end of the crystallization process, the average fluctuation component of the chemical potential within the confined amorphous regions, $\overline{\Delta\mu}A statistical mechanical model is used to analyze literature data regarding the restricted segmental dynamics of a number
of crystallized polymers, as observed by means of broadband dielectric spectroscopy. A relationship between well defined physical
quantities and the width parameter in the Havriliak–Negami representation of symmetric processes is established. It is found
that, for materials crystallized from an isotropic amorphous state, the segmental relaxation process is associated to conformational
changes within cooperatively rearranging regions of ~1 nm diameter. In case of chain orientation, the dimension of the rearranging
regions along the chain direction increases up to 3–5 nm. It is argued that the average size of the rearranging regions may
influence the thickness of the amorphous interlamellar layers in the stacks. It is also found in all cases that, at the end
of the crystallization process, the average fluctuation component of the chemical potential within the confined amorphous
regions, [`(Dm)]\overline{\Delta\mu}, is of the same order of the chemical potential drop Δμ
cryst associated to crystallization from the undercooled, relaxed melt. Except in one among the cases considered, it is found that
[`(Dm)] ? - Dmcryst\overline{\Delta\mu}\approx - \Delta\mu_{\rm cryst}, which is a hint towards the formalization of a thermodynamic criterion for crystallization arrest. 相似文献
14.
V. V. Kochervinskii S. A. Bedin I. V. Razumovskaya M. A. Shcherbina M. I. Buzin I. A. Malyshkina A. M. Prazdnichnyi A. S. Pavlov O. I. Vasilevskii 《Polymer Science Series A》2016,58(3):345-356
The processes of molecular mobility in vinylidene fluoride–tetrafluoroethylene ferroelectric copolymer–based films textured via uniaxial drawing are studied. It is found that the cooperative mobility in the amorphous regions of the copolymer is described by the Vogel–Fulcher equation, whose parameters are sensitive to the drawing conditions. It is shown that a decrease in the drawing temperature causes a reduction in the effective activation energy of the above-mentioned motion. In accordance with the X-ray diffraction data, this circumstance may be explained by an increase in the packing density of chains in interlamellar spaces. This effect is partially provided by deformation-induced processes of formation of small and defective crystals of the paraelectric or antiferroelectric phase in spaces between neighboring lamellar crystals at the primary stage of crystallization. The relationship between the value of the orientational polarization in oriented films and the topology of structure formation in microfibrils is discussed. It is observed that enlargement of the interlamellar space (filled with a liquidlike amorphous phase) between neighboring crystals in microfibrils promotes an increase in the orientational polarization of chains in the amorphous phase. 相似文献
15.
L. S. Tsybul’skaya V. A. Kukareko Yu. N. Bekish T. V. Gaevskaya A. G. Kononov 《Russian Journal of Applied Chemistry》2008,81(9):1554-1558
Polycrystalline and amorphous cobalt-boron coatings were electrochemically deposited. The effect of the boron content and heating temperature on the physicomechanical properties of the coatings was studied. A relationship between the composition, structure, and properties of the coatings was established. 相似文献
16.
The glass transition behaviors of amorphous ice with different thicknesses are studied by determining the heat capacity of low-density amorphous ice without crystallization using first principle molecular dynamics (FP-MD) and classical MD methods. The behaviors are also studied by analyzing hydrogen-bond network, the radial distribution functions, and relationship between hydrogen bond and electronic structures. It is found that the glass transition temperature (T(g)) in the range of 90 K < T < 100 K for 4 nm amorphous ice film by FP-MD method, and 120 K < T(g) < 130 K for 8 nm amorphous ice film by MD method. Meanwhile, T(g) decreases with the decreasing thickness of amorphous ice film, which is also validated by the theoretical model. 相似文献
17.
Membranes with well characterized structures were prepared for study of the relationship between the structure, the state of swelling water and the transport phenomena. These membranes consist of polyvinylalcohol (PVA) with various amounts of grafted octadecylic chains. The method of grafting leads to sequential grafting with unreacted hydroxylic groups between adjacent grafted paraffinic chains. A spherulitic texture, including an amorphous part made of ungrafted PVA, was observed. DSC and swelling measurements show that the water content of the lamellar spherulitic phase was constant regardless of the grafting ratio and that the water in this phase was unable to crystallize. In the amorphous zones, the crystallizable and non-crystallizable water co-existed in a ratio closely related to the grafting ratio. Transport properties have been studied using various methods. A porous type transport without selectivity occurs through the amorphous zones together with a selective diffusive type transport through the spherulites. Using a porous plug model, amorphous zones are characterized by an equivalent pore diameter of about 30 Å. The number of those pores increases when the grafting ratio decreases and their sizes vary under the effect of the applied pressure. The diffusive transport, unaffected by the applied pressure, takes place through the interlamellar spaces, which are characterized by a water thickness of about 15 Å in which the ordering of the water is probably responsible for the selectivity. 相似文献
18.
W. Okumura Y. Ohkoshi Y. Gotoh M. Nagura H. Urakawa K. Kajiwara 《Journal of Polymer Science.Polymer Physics》2004,42(1):79-90
The structure, mechanical properties, and thermomechanical properties of poly(ethylene terephthalate) (PET) fibers obtained by laser-heated drawing were investigated in terms of their dependence on the draw ratio and feed speed and the differences between neck-drawn fibers and flow-drawn fibers. The long period at a draw ratio of 6.0 reached 19.0 nm, notably larger than at lower ratios, whereas the tilting angle of the laminar structure was constant at about 60°, regardless of the draw ratio. A maximum value of 15.0 GPa was attained for the initial modulus, and 1.07 GPa was attained for the tensile strength. A higher tensile strength orientation-induced crystallized fiber at the same initial modulus was obtained from higher molecular weight PET. The relationship between the compliance and molecular orientation of the amorphous phase was studied with a series model of crystalline and amorphous phases. The results revealed that, in the high-draw-ratio fibers, the compliance of the amorphous phase decreased with the draw ratio at a higher rate than indicated by extrapolation to intrinsic values. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 79–90, 2004 相似文献
19.
改性Ni-B合金的制备及其催化糠醛加氢性能的研究 总被引:2,自引:0,他引:2
非晶态合金是一类介于晶态和无定形物质之间的特殊材料,其组成元素之间以金属键相连并在几个晶格常数范围内保持短程有序而长程无序,这种独特结构使其具有优良的催化性能,并大多被用于加氢反应例如,苯加氢制环己烷[1,2],硝基苯加氢制苯胺[3,4],环戊二烯选择加氢[5],腈类加氢[6, 相似文献