Spinodal phase separation behavior of poly(methyl methacrylate)/poly(styrene-co-acrylonitrile) (PMMA/SAN) blends was investigated by the time-resolved small angle light scattering (SALS) technique. It was found that t...Spinodal phase separation behavior of poly(methyl methacrylate)/poly(styrene-co-acrylonitrile) (PMMA/SAN) blends was investigated by the time-resolved small angle light scattering (SALS) technique. It was found that the influence of temperature on the scattering intensity evolution followed the time-temperature superposition principle. The relationship between temperature and the relaxation ti me of scattering intensity I(t) can be well described by the Williams-Landel-Ferry (WLF) function.展开更多
Using the time-temperature superposition principle, the dynamic properties of viscoelastic materials can be shifted to obtain a master curve. A shifting method based on the Generalized Maxwell Model （ GMMBS ） , is p...Using the time-temperature superposition principle, the dynamic properties of viscoelastic materials can be shifted to obtain a master curve. A shifting method based on the Generalized Maxwell Model （ GMMBS ） , is proposed for the time-temperature superposition process of thermo-rheological simple, linear viscoelastic materials. Experimental data points under different temperatures are all considered as a whole and expressed with one unified representation by the GMMBS, which utilizes the feature that the Generalized Maxwell Model can describe a large class of viscoelastic materials with needed accuracy. Compared with traditional overlapping window based shifting methods, the proposed constitutive model based method needn＇t judge the size or existence of the overlapping window first, and computes shift factors with useful information contained in all experimental data points. The effectiveness of the proposed method is verified by simulated data, generated from published test results, with various experimental noise levels, densities of data points and sizes of overlapping windows. It has been shown that the GMMBS is robust and accurate.展开更多
The real random number generation is a critical problem in computer science.The current generation methods are either too dangerous or too expensive,such as using decays of some radioactive elements.They are also hard...The real random number generation is a critical problem in computer science.The current generation methods are either too dangerous or too expensive,such as using decays of some radioactive elements.They are also hard to control.By the declaration of uncertainty principles in quantum mechanics,real probabilistic events can be substituted by easier and safer processes,such as electron diffraction,photon diffraction and qubits.The key to solve the problem of Schr?dinger’s cat is to identify that the atom stays in different states after and before the decay,and the result of the decay is probabilistic according to the wave packet co llapse hypothesis.Same matter is able to possess different kinds of properties such as wave-particle duality due to that it can stay in various states,and which state will the matter stay is determined by the chosen set of physical quantities(or mechanical quantities).One eigenstate of a set of physical quantities can be a superpos ition of other eigenstates of different sets of physical quantities,and the collapse from a superposition to an eigenstate it contains is really random.Using this randomness,real random number can be generated more easily.展开更多
通过准静态力学性能实验和动态热机械实验研究Q411T聚脲材料的基本力学性能和动态热机械性能;基于时温等效原理(TTS)拟合Q411T聚脲的损耗模量、储能模量主曲线,研究Q411T聚脲吸能特性。采用4 kg钢球进行落球冲击试验,通过DH5960动态信...通过准静态力学性能实验和动态热机械实验研究Q411T聚脲材料的基本力学性能和动态热机械性能;基于时温等效原理(TTS)拟合Q411T聚脲的损耗模量、储能模量主曲线,研究Q411T聚脲吸能特性。采用4 kg钢球进行落球冲击试验,通过DH5960动态信号测试分析系统采集钢板在冲击荷载作用下的应变时程曲线,分析有无防护涂层的钢板抗冲击防护效果。结果表明:Q411T型聚脲材料具有良好的力学性能和抗冲击能力,材料的玻璃化转变温度为-20℃,损耗因子的峰值为0.18,在常温状态下材料的损耗因子大于0.12,具有一定的吸能特性;落球冲击试验表明,在钢板迎撞面喷涂2 mm Q411T涂层可以有效抑制结构变形,试样挠度下降45%,钢板抗冲击性能显著提高。展开更多
Time-temperature superposition principle (TTSP) was used to examine dynamic viscoelastic properties of Chinese Fir(Cunninghamia lanceolata) wood at an extremely low moisture content(0.6%).Storage modulus and loss fact...Time-temperature superposition principle (TTSP) was used to examine dynamic viscoelastic properties of Chinese Fir(Cunninghamia lanceolata) wood at an extremely low moisture content(0.6%).Storage modulus and loss factor data were obtained at different constant temperatures ranging from 25℃to 150℃in frequency multiplexing experiments(0.1 -20 Hz).All viscoelastic curves at other temperatures were shifted along the log-frequency axis to superimpose them on a reference temperature(i.e.135℃in this study) curve.The extended storage modulus and loss factor isothermal master curves were over a wide range of frequency.The shift factors were determined to be a function of temperature and fitted into the Arrhenius equation with the least squares method.The results showed that the storage modulus data were excellently fitted into the Arrhenius model,indicating the validity of the model to characterize the dynamic stiffness behavior of dry wood in the range of 25-150℃using the TTSP. However,the time-temperature equivalence was not able to predict the damping properties.展开更多
基金This work was supported by the Special Funds for Major State Basic Research Projects (Grand G1999064800)
文摘Spinodal phase separation behavior of poly(methyl methacrylate)/poly(styrene-co-acrylonitrile) (PMMA/SAN) blends was investigated by the time-resolved small angle light scattering (SALS) technique. It was found that the influence of temperature on the scattering intensity evolution followed the time-temperature superposition principle. The relationship between temperature and the relaxation ti me of scattering intensity I(t) can be well described by the Williams-Landel-Ferry (WLF) function.
基金supported by the National Science and Technology Major Project through the contract 2010zx04008-041
文摘Using the time-temperature superposition principle, the dynamic properties of viscoelastic materials can be shifted to obtain a master curve. A shifting method based on the Generalized Maxwell Model （ GMMBS ） , is proposed for the time-temperature superposition process of thermo-rheological simple, linear viscoelastic materials. Experimental data points under different temperatures are all considered as a whole and expressed with one unified representation by the GMMBS, which utilizes the feature that the Generalized Maxwell Model can describe a large class of viscoelastic materials with needed accuracy. Compared with traditional overlapping window based shifting methods, the proposed constitutive model based method needn＇t judge the size or existence of the overlapping window first, and computes shift factors with useful information contained in all experimental data points. The effectiveness of the proposed method is verified by simulated data, generated from published test results, with various experimental noise levels, densities of data points and sizes of overlapping windows. It has been shown that the GMMBS is robust and accurate.
文摘The real random number generation is a critical problem in computer science.The current generation methods are either too dangerous or too expensive,such as using decays of some radioactive elements.They are also hard to control.By the declaration of uncertainty principles in quantum mechanics,real probabilistic events can be substituted by easier and safer processes,such as electron diffraction,photon diffraction and qubits.The key to solve the problem of Schr?dinger’s cat is to identify that the atom stays in different states after and before the decay,and the result of the decay is probabilistic according to the wave packet co llapse hypothesis.Same matter is able to possess different kinds of properties such as wave-particle duality due to that it can stay in various states,and which state will the matter stay is determined by the chosen set of physical quantities(or mechanical quantities).One eigenstate of a set of physical quantities can be a superpos ition of other eigenstates of different sets of physical quantities,and the collapse from a superposition to an eigenstate it contains is really random.Using this randomness,real random number can be generated more easily.
文摘通过准静态力学性能实验和动态热机械实验研究Q411T聚脲材料的基本力学性能和动态热机械性能;基于时温等效原理(TTS)拟合Q411T聚脲的损耗模量、储能模量主曲线,研究Q411T聚脲吸能特性。采用4 kg钢球进行落球冲击试验,通过DH5960动态信号测试分析系统采集钢板在冲击荷载作用下的应变时程曲线,分析有无防护涂层的钢板抗冲击防护效果。结果表明:Q411T型聚脲材料具有良好的力学性能和抗冲击能力,材料的玻璃化转变温度为-20℃,损耗因子的峰值为0.18,在常温状态下材料的损耗因子大于0.12,具有一定的吸能特性;落球冲击试验表明,在钢板迎撞面喷涂2 mm Q411T涂层可以有效抑制结构变形,试样挠度下降45%,钢板抗冲击性能显著提高。
文摘Time-temperature superposition principle (TTSP) was used to examine dynamic viscoelastic properties of Chinese Fir(Cunninghamia lanceolata) wood at an extremely low moisture content(0.6%).Storage modulus and loss factor data were obtained at different constant temperatures ranging from 25℃to 150℃in frequency multiplexing experiments(0.1 -20 Hz).All viscoelastic curves at other temperatures were shifted along the log-frequency axis to superimpose them on a reference temperature(i.e.135℃in this study) curve.The extended storage modulus and loss factor isothermal master curves were over a wide range of frequency.The shift factors were determined to be a function of temperature and fitted into the Arrhenius equation with the least squares method.The results showed that the storage modulus data were excellently fitted into the Arrhenius model,indicating the validity of the model to characterize the dynamic stiffness behavior of dry wood in the range of 25-150℃using the TTSP. However,the time-temperature equivalence was not able to predict the damping properties.
