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Structural relaxation.of Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(22.5) bulk metallic glass under high pressure

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Science China(Physics,Mechanics & Astronomy) 2003年第5期46卷 468-473页

作者：李工孙力玲张君刘日平景勤王文魁高云鹏陈丹 Key Laboratory of Metastable Materials Science and Technology Qinhuangdao 066004 China Institute of Physics & Center for Condensed Matter Physics Chinese Academy of Sciences Beijing 100080 China Institute of Physics & Center for Condensed Matter Physics Chinese Academy of Sciences Beijing 100080 China Key Laboratory of Metastable Materials Science and Technology Qinhuangdao 066004 China Key Laboratory of Metastable Materials Science and Technology Qinhuangdao 066004 ChinaInstitute of Physics & Center for Condensed Matter Physics Chinese Academy of Sciences Beijing 100080 China Beifang Mingjing Glass Com. Ltd. Qinhuangdao 066004 China Tianjin Heavy Machinery Company Tianjin 300400 China

Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass (BMG) is annealed at 573 K under 3 GPa and its structural relaxation.is investigated by X-ray diffraction, ultrasonic study, compression as well as sliding wear measurements. It is found that after the ZrTiCuNiBe BMG sample was annealed under high pressure, the mechanical properties were improved. Moreover, the BMG with relaxed structure exhibits markedly different acoustic properties. These results are attributed to the fact that relaxation.under high-pressure results in a microstructural transformation in the BMG.

关键词： Zr41Ti14Cu12.5Ni10Be22.5, bulk metallic glass, high pressure, structure relaxation.

Conformation and dynamics of polyoxyethylene lauryl ether (Brij-35) chains in aqueous micellar solution studied by 2D NOESY and 1H NMR relaxation

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Science China Chemistry 2002年第2期45卷 143-150页

作者：高红昌方晓雯毛诗珍袁汉珍赵濉程功臻俞稼镛杜有如 State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences Wuhan 430071 China

Spin-lattice relaxation.time, spin-spin relaxation.time and two-dimensional nuclear Overhauser enhancement spectroscopy (2D NOESY) experiments of polyoxyethylene lauryl ether (Brij-35) micelles in aqueous solutions at a concentration of 100 times the critical micellar concentration (cmc) give direct evidence that the hydrophilic polyoxyethylene chains, staying in the exterior of the micellar core, are coiled, bent and aligned around the micellar core with a certain number of water molecules included. This hydrophilic layer is in contact with the solvent, water, keeping the micellar solution stable. 1H NMR relaxation.time measurements show that the first oxyethylene group next to the alkyl chain participates in the formation of the surface area of the micellar core. The motion of the hydrophilic polyoxyethylene chains is less restricted as compared with the hydrophobic alkyl chains.

关键词： polyoxyethylene lauryl ether (Brij-35), 2D NOESY, micellar structure and dynamics, relaxation.

Diffusion theory of slow responses

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Science China Mathematics 1997年第3期40卷 290-296页

作者：李景德陈敏郑凤周镇宏 Department of Physics Zhongshan Univcrsity Guangzhou 510275 China

When an action is applied to a macroscopic substance, there is a particular sort of slow response he sides the well-known fast response. Using diffusion theory, the characteristics of slow response in dielectric, elastic, piezoelectric, and pyroelectric relaxation.may he explained A time domain spectroscopy method suitable for slow and fast responses in linear and nonlinear effects is given. Every relaxation.mechanism contributes a peak in differential spectroscopy, and its position, height, and line shape show the dynamical properties of the mechanism The method of frequency domain spectroscopy is suitable only for linear fast response. Time domain spectroscopy is another nonequiv-alent powerful method. The theory is confirmed by a lot of experimental data

关键词： slow response time domain space charge dielectric relaxation.

Torsional Properties and Torque relaxation.of Cashmere Yarn

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Journal of Donghua University(English Edition) 2002年第3期19卷 68-72页

作者：侯秀良刘启国王善元 Coll. of Textiles Dong Hua Univ. Shanghai 200051 China Nantong Inst. of Technol. Nantong 226007 China

By means of a torque testing apparatus with heat case and steam, the torque-twist relationship and torque-relaxation.of cashmere yarn are investigated in comparison with wool yarn under two conditions of standard state and heating and steaming state, and the effect of pre-tension on the torque-relaxation.of cashmere yarn is also *** shows that (1) the torque of cashmere yarn is lower than that of wool yarn under the same conditions, (2) the torques of wet cashmere and wool yarns are both lower than that of cashmere and wool yarns under standard conditions, (3) the torque hysteresis for cashmere yarn is smaller and its level and rate of torque relaxation. are lower than that of wool yarn, and (4) the percentage of residual torque of cashmere yarn increases with increasing pre-tensions (630 cN).

关键词： cashmere yarn, wool yarn, torsional properties,torque, relaxation.

CRYSTALLIZATION OF AMORPHOUS LiBO_(2) AND ITS PHASE TRANSITION

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Science China Mathematics 1990年第5期33卷 595-606页

作者：梁敬魁柴璋赵书清 Institute of Physics Academia Sinica Beijing 100080 PRC Graduate School of University of Science and Technology of China Academia Sinica Beijing 100039 PRC Institute of Artificial Crystal Academy of Materials Beijing 100018 PRC

The crystallization of amorphous LiBO2 and its phase transition have been investigated by the X-ray diffraction, thermal analysis and infrared absorption spectrum. As the amorphous LiBO2 crystallizes, the metastable phase δ-LiBO2 is formed first. The boron-oxygen group in crystal of the δ-phase is similar to that in amorphous LiBO2. As the temperature rises, the δ-phase transforms to the γ-phase, which cannot be prepared at ordinary pressure, and then the γ-phase transforms to the α-phase. Structural relaxation.takes place before crystallization. At an equal rising rate of temperature, the larger the particle size of amorphous LiBO2 is, the higher the crystallization temperature will be.

关键词： LiBO2 crystallization phase transition structural relaxation.

OPTIMAL CONTROL OF A CLASS OF INFINTIE DIMENSIONAL UNCERTAIN SYSTEMS

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Acta Mathematica Scientia 1994年第S1期14卷 78-87页

作者：项筱玲 Department of Mathematics Guizhou University Guiyang 550025 China

In this paper, we use relaxation.theory to study a class of relaxed infinite dimensional uncertain *** obtained the exisence and some important properties of solutions of relaxed systems first. Then the existence of optimal control of relaxed systems witha correspondingly relaxed cost functional was proved. Lastly, we showed that under someassumptions the set of original trajectories is dense in the set of relaxed trajectories and therelaxed control problem is equivalent to the original one.

关键词： Optimal control Uncertain systems relaxation.

Colossal dielectric response and complex impedance analysis of LaFeO_(3)ceramics

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Journal of Advanced Dielectrics 2022年第5期12卷 60-66页

作者： Sushrisangita Sahoo K.P.Andryushin P.K.Mahapatra R.N.P.Choudhary Research Institute of Physics Southern Federal University 344090Rostov-on-DonRussia Department of Physics Siksha O Anusandhan(Deemed to be University)BhubaneswarIndia

The present investigations mainly focused on the colossal dielectric response and complex impedance analysis of LaFeO3 *** studied sample was prepared by a citrate gel *** and microstructural properties are analyzed from the XRD pattern and SEM *** anomalies in the dielectric constant versus temperature plots are analyzed on the basis of polarization induced by the Maxwell-Wagner mechanisms and ferromagnetic interaction between the Fe3+ions driven by the oxygen vacancy mediated Fe^(3+)-Vo-Fe3+exchange interaction A giant dielectric permittivity in the order of~105 was observed in the sample even at the room temperature for 100 *** colossal dielectric constant in LaFeO3 is mainly driven by the internal barrier layer capacitor(IBLC)*** formation of IBLC was explained on the basis of highly insulating grain boundary and less resistive/semiconducting grain,which was confirmed from both the resistance and capacitance of grain and grain boundary from the impedance *** non-Debye-type relaxation.process associated with the grain and grain boundary effect was investigated from the broad and asymmetric relaxation.*** relaxation.time for both the grain and grain boundary effect was also *** addition to this,we have also analyzed the normalized bode plot of imaginary part of impedance and electrical modulus which suggests the relaxation.process dominated by the short-range movement of charge carriers.

关键词： Ferrite giant dielectric constant non-Debye relaxation.

The strong cross relaxation.of Er3+ and Yb3+ ions in the oxvfluoride glass ceramics

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Chinese Science Bulletin 2000年第10期45卷 882-885页

作者： ZHANG Guangyin, ZHAO Lijuan, HOU Yanbing, XU Jingjun & SHANG Meiru1. Photonics Center, College of Physical Science, Nankai University, Tianjin 300071, China 2. Institute of Photon-Electron Technology, North Traffic University, Beijing 100044, China

Oxyfluoride glass ceramic is a new up-conversion fluorescent material with the low phonon energy just like fluoride and the good mechanical stability like oxide. In the oxyfluoride glass ceramics co-doped with Er3+ and Yb3+ ions, the red radiation is dominant while it is excited by the violet light. But in the general fluorescent material, the green radiation is dominant because the multi-phonon relaxation.occurs step by step. The strong cross relaxation.process of Er3+ and Yb3+ ions is mainly responsible for enhancement of the red radiation intensity in the oxyfluoride glass ceramics. The increase of the red radiation intensity of Er3+ ions by the violet light excitation shows that the rare earth ions are doped into fluoride micro-crystals which are planted into oxide host in the oxyfluoride glass ceramics.

关键词： oxyfluoride glass ceramics cross relaxation non-radiation relaxation.