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91.
92.
D. Radic L. H. Tagle A. Opazo A. Godoy L. Gargallo 《Journal of Thermal Analysis and Calorimetry》1994,41(5):1007-1018
Poly(monoitaconates) containing octyl, decyl and dodecyl groups and random monoalkylitaconate-co-vinylpyrrolidone copolymers were studied by thermogravimetric analysis. Copolymers of mono-n-octylitaconate (MOI), mono-n-decylitaconate (MDI), and mono-n-dodecylitaconate (MDoI), respectively, with N-vinyl-2-pyrrolidone (VP) of different compositions were studied by dynamic thermogravimetric analysis. The thermal stability of the copolymers depends on the structure of the monoitaconate comonomer and on the composition of the copolymer The kinetic analysis of the degradation data shows that the thermal decomposition of these copolymers can be described by several kinetic orders depending on the copolymer and on the composition. The relative thermal stability of the copolymers increases as the VP content increases and as the length of the side chain of the itaconate increases, following the same trend as the flexibility of the copolymers in solution. 相似文献
93.
An intensity-modulated optical fibre sensor system is described which employs a single LED source to provide the measurand and the reference signals with two separate wavelength bands. The allocated wavelength bands are selected to minimize any differential intensity effects that may arise from LED thermal variations. The sensor system, comprising a transceiver unit connected to an optical displacement sensor using a single optical fibre, provides an output fully referenced for all major common-mode variations that are likely to occur. Performance characteristics for the prototype system are reported which show a linear displacement range of over 20 mm. 相似文献
94.
本文在Skyr}e相互作用、核物质近似和自洽半经典方法的基础上,将微观光学势的自洽研究推J“到中能区(60-r300MeV),研究了”+907r在该能区光学势的径向形状和温度效应 相似文献
95.
We present a calculation of the electronic Raman cross section for the scattering of light across the energy gap of an antiferromagnetic insulator. The antiferromagnet is described in terms of a spin density wave state for the Hubbard model at half filling. We consider the coupling of the light to the current density and the inverse mass tensor on equal footing. A comparison of the cross section for different scattering geometries is given. 相似文献
96.
The motivation of this work is to provide reliable and accurate modeling studies of the physical (surface, thermal, mechanical and gas diffusion) properties of chitosan (CS) polymer. Our computational efforts have been devoted to make a comparison of the structural bulk properties of CS with similar type of polymers such as chitin and cellulose through cohesive energy density, solubility parameter, hydrogen bonding, and free volume distribution calculations. Atomistic modeling on CS polymer using molecular mechanics (MM) and molecular dynamics (MD) simulations has been carried out in three dimensionally periodic and effective two dimensionally periodic condensed phases. From the equilibrated structures, surface energies were computed. The equilibrium structure of the films shows an interior region of mass density close to the value in the bulk state. Various components of energetic interactions have been examined in detail to acquire a better insight into the interactions between bulk structure and the film surface. MD simulation (NPT ensemble) has also been used to obtain polymer specific volume as a function of temperature. It is demonstrated that these V–T curves can be used to locate the volumetric glass transition temperature (Tg) reliably. The mechanical properties of CS have been obtained using the strain deformation method. Diffusion coefficients of O2, N2, and CO2 gas molecules at 300 K in CS have been estimated. The calculated properties of CS are comparable with the experimental values reported in the literature. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1260–1270, 2007 相似文献
97.
We have studied the temperature dependence of the radiative deactivation of the Pd-porphine triplet states in Shpol’skii matrices
in the temperature range 1.2–210 K. A substantial transformation of the phosphorescence spectra is observed as the temperature
increases and is due to the inclusion of thermally activated Pd-porphine states in the radiative deactivation processes. The
activation energy Ea of these Pd-porphine states is measured in matrices of n-octane and n-nonane. The splitting of the lowest quasidegenerate
triplet state ΔE(T2−T1) is determined for planar and distorted conformations of the Pd-porphine macrocycle in the n-octane matrix as 40 and 57 cm−1, respectively. The ability to use the temperature dependence of the phosphorescence properties of Pd-porphine to fabricate
molecular thermometers for the low-temperature range is analyzed.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 4, pp. 460–464, July–August, 2007. 相似文献
98.
The patterns of absorption and reflection of an ultrashort laser pulse by a plasma with a solid-state density, which are realized in the mode of the normal skin effect, are studied. It is shown that a decrease in low-power pulse duration shorter than the period corresponding to the fundamental frequency of radiation leads to an increase in the absorption coefficient. If the pulse power is so high as to provide electron heating during a time shorter than the reciprocal fundamental frequency, nonlinear suppression of absorption takes place and the spectrum of the reflected radiation contains odd harmonics of the fundamental frequency. 相似文献
99.
基于半导体材料的新型光纤温度传感器 总被引:1,自引:0,他引:1
提出利用全反射定律以半导体材料作为敏感器件的光纤温度传感器,着重阐述半导体材料的温度敏感特性及传感原理,介绍传感器构造,并给出初步实验方案。 相似文献
100.