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THE STABILITY INVESTIgATION OF FERROELECTRIC SrBi_2Ta_2O_9 THIN FILMS ANNEALED IN FORMINg gAS

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Acta Metallurgica Sinica(English Letters) 2002年第1期15卷 58-60页

作者： T. Yu D.S. Wang D. Wu A.D. Li A. Hu z.g. liu N.B. Ming National Laboratory of Solid State Microstructures Nanjing University Nanjing 210093 China

The hysteresis loop changes of ferroelecric SrBi_2 Ta_2 O_9 (SBT) thin films(330nm) us the temperature of forming gas (5 percent hydrogen+95 percent nitrogen) annealing weremeasured when the annealing time was 1min and 10min. The selected annealing temperature was at 100deg C,200 deg C 250 deg C, 300 deg C, 350 deg C,400 deg C and 450 deg C, respectively. Our resultsshowed that the ferroelectric properties were easily destroyed and the leakage current changedabruptly when the SBT thin films were in their ferroelectric phase (g C). The space chargesat the grain boundary may take an important role' in absorption polarity molecular hydrogen when theSBT thin films were in the ferroelectric phase. The oxygen recovery experiments were also performedand investigated in this work.

关键词： ferroelectric SrBi_2 Ta_2 O_9 thin film stability forming gas

FERROELECTRIC CHARACTERISTICS OF SrBi_2Ta_2O_9 THIN FILMS ANNEALED IN FORMINg gAS

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Acta Metallurgica Sinica(English Letters) 2001年第6期14卷 517-519页

作者： D.S. Wang, T. Yu and A. Hu (Department of Physics & National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China) D. Wu, A.D. Li, z.g. liu and N.B. Ming (Department of Material Science and Engineering & National Laboratory Dept. of Phys. Nanjing Univ. Nanjing 210093 China

The degradation behavior of SrBi2Ta2O9 (SBT) thin films annealed in forming gas (5%H2+95%N2) was investigated. The ferroelectric remnant polarization Px of SBT had a severe decrease in the containing H2 atmosphere at 400°C. SEM results showed that Bi could be reduced from SBT thin films for the effect of H2. The reduction role increased with a rise of annealing temperature. SBT thin films lost their ferroelectricity when the annealing temperature was above 450°C. It implied that the degradation of Pr value or the disappearance of ferroelectricity in SBT thin, films had the relationship with the reductive amounts of Bi in SBT. H2 played an important role in degradation of ferroelectric SBT thin films. This role could be attributed to its strong reduction activity during forming gas annealing.

关键词： Annealing Degradation Ferroelectricity Thermal effects

LASER LIFT-OFF OF gaN THIN FILMS FROM SAPPHIRE SUBSTRATES

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Acta Metallurgica Sinica(English Letters) 2001年第6期14卷 448-452页

作者： J. Xu, R. zhang, Y.P. Wang, X.Q. Xiu, S.L. gu, B. Shen, Y. Shi, z.g. liu and Y.D. zheng (Department of Physics and National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China) Dept. of Phys. Nanjing Univ. Nanjing 210093 China

gallium Nitride film was successfully separated from sapphire substrate by laser radiation. The absorption of the 248 nm radiation by the gaN at the interface results in rapid thermal decomposition of interfacial layer, yielding metallic ga and N2 gas. The substrate can be easily removed by heating above the ga melting point (29°C). X-ray diffraction, atomic force microscopy and photoluminescence of gaN before and after lift-off process have been performed, which demonstrated that the separation and transfer process do not alter the structural quality of the gaN films. And further discussions on the threshold energy and crack-free strategies of laser lift-off process have also been presented.

关键词： gallium compounds Laser beam effects Nitrides Sapphire Separation

LOW CYCLE FATIgUE BEHAVIOR OF Az91HP ALLOY IN AS HIgHP RESSURE DIE CASTINg

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Acta Metallurgica Sinica(English Letters) 2000年第4期13卷 961-966页

作者： liu, z. Xu, Y.Y. Wang, z.g. Wang, Y. liu, z.Y. Inst of Metal Research Chinese Acad of Sciences Shenyang China

Fully reversed total strain-controlled low-cycle fatigue tests were conducted at room temperature in air to study the fatigue behavior of Az91HP magnesium alloy in as high pressure die casting and subsequently heat treatment. All the specimens in different heat histories exhibit cyclic strain hardening in different degrees. It is difficult to distinguish the fatigue behavior of the die casting specimens from that of the solution aging specimens. The solution treated specimens show longer fatigue life at high strain amplitude and shorter fatigue life at low strain amplitude than the die casting and solution aging specimens though they have the lowest yield strength with higher strain hardening. Fatigue fracture surfaces for strain amplitude larger than 0.005 show very similar to those found by monotonic tensile tests. The SEM examination reveals that the regions of fatigue crack growth and final fracture can be characterized by quasi-cleavage mechanisms, but some shallow dimples, slip bands and secondary cracks are found on the fracture surface in the fracture crack growth areas.

关键词： Cracks Die casting Fatigue of materials Heat treatment

Electron Beam Curing of Advanced Composites

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Journal of Materials Science & Technology 2000年第6期16卷 627-630页

作者： Sui, g. zhong, W.H. zhang, z.g. Dep. of Materials Sci. and Eng. Beijing Univ. of Aeron. and Astron. Beijing 100083 China

The fundamental concept of electron beam method and the application in cure of composites are elaborated in this paper. The components of electron beam curing system are introduced. The mechanisms of interaction between electron beam and polymer matrix composites are presented. Recent studies including work of authors themselves on electron beam curing of composites are also discussed. Moreover, the authors believe that it is necessary to do the basic research about understanding how electron beam affects cured network and the mechanical/physical properties of the composites for establishing a quantitative or semi-quantitative formulation.

关键词： Electron Beam Curing of Advanced Composites EB

Targeting epigenetic mechanisms in amyloid-β-mediated Alzheimer’s pathophysiology:unveiling therapeutic potential

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Neural Regeneration Research 2025年第1期20卷 54-66页

作者： Jennie z.Li Nagendran Ramalingam Shaomin Li Ann Romney Center for Neurologic Diseases Brigham and Women’s Hospital and Harvard Medical SchoolBostonMAUSA

Alzheimer’s disease is a prominent chronic neurodegenerative condition characterized by a gradual decline in memory leading to *** evidence suggests that Alzheimer’s disease is associated with accumulating various amyloid-βoligomers in the brain,influenced by complex genetic and environmental *** memory and cognitive deficits observed during the prodromal and mild cognitive impairment phases of Alzheimer’s disease are believed to primarily result from synaptic *** life,environmental factors can lead to enduring changes in gene expression and the emergence of brain *** changes,known as epigenetic modifications,also play a crucial role in regulating the formation of synapses and their adaptability in response to neuronal *** this context,we highlight recent advances in understanding the roles played by key components of the epigenetic machinery,specifically DNA methylation,histone modification,and microRNAs,in the development of Alzheimer’s disease,synaptic function,and activity-dependent synaptic ***,we explore various strategies,including enriched environments,exposure to non-invasive brain stimulation,and the use of pharmacological agents,aimed at improving synaptic function and enhancing long-term potentiation,a process integral to epigenetic ***,we deliberate on the development of effective epigenetic agents and safe therapeutic approaches for managing Alzheimer’s *** suggest that addressing Alzheimer’s disease may require distinct tailored epigenetic drugs targeting different disease stages or pathways rather than relying on a single drug.

关键词： Alzheimer’s disease DNA methylation enriched environments histone modification microRNAs non-invasive brain stimulation synaptic plasticity

A High Power Conversion Efficiency L-Band Erbium Doped Fiber Amplifier

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光学学报 2003年第S1期23卷 383-384页

作者： z.g. Lu C.P. grover Institute for National Measurement Standards National Research Council M-50 1200 Montreal Road Ottawa ON K1 A OR6 CanadaInstitute for National Measurement Standards National Research Council M-50 1200 Montreal Road Ottawa ON K1 A OR6 Canada

By using two sections of erbium doped fiber and a fiber optical reflector, a novel, highly efficient L-band amplifier is demonstrated with significantly power-conversion-efficiency enhancement and the gain increasing ... 详细信息

关键词： EDFA as of length high with A High Power Conversion Efficiency L-Band Erbium Doped Fiber Amplifier ASE been for

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HIgH-TEMPERATURE LOW-CYCLE FATIgUE BEHAVIOR OF NICKEL-BASED SUPERALLOY gH4049

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Acta Metallurgica Sinica(English Letters) 1999年第1期12卷 12-15页

作者： Chen, L.J. Yao, g. Wang, z.g. Tian, J.F. Inst of Metal Research The Chinese Acad of Sciences Shenyang China

The cyclic stress response and lowcycle fatigue life for wrought nickelbased superalloy gH4049 were investigated in the temperature range from 500 to 800 The relationship between the strain amplitude and the number of stress reversals was given. The behavior of cyclic hardening was observed for higher strain amplitudes at all testing temperatures and the lowcycle fatigue life generally decreased with increasing testing temperature for the same strain range. In addition, fracture surfaces of the fatigued samples were examined by using a scanning electron microscope.

关键词： superalloy low cycle fatigue fatigue life

CHANgES OF gLOMERULAR FIXED ANIONIC CHARgE SITES IN ADRIAMYCIN NEPHROSIS IN RATS

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中华医学杂志(英文版) 1991年第2期104卷 128-131+176-177页

作者： z Wang z.g.Wang z liu Department of Pediatrics Second Teaching Hospital West China University of Medical Sciences Chengdu.

A single intravenous injection of adriamycin (5 mg/kg) into rats induced nephrotic syndrome. In the various stages of the model, alterations of glomerular fixed anionic charge sites stained with colloidal iron were analyzed quantitatively by image analyzer, which is reported here for the first time. The results showed that there was a significant decrease in glomerular fixed anionic charge sites at 3 hours after administration of adriamycin as compared with the control animals (Pge sites preceded the onset of proteinuria and steadily increased along with the progress of the disease. The results suggest that the loss of glomerular fixed anionic charge sites may play an important role in the development of proteinuria in nephrotic syndrome.

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