Scaling behavior of dynamic hysteresis of PMN-PT relaxor ferroelectric ceramics near the morphotropic phase boundary

Due to the feature of domains, ferroelectric materials display hysteresis behavior with respect to the change of the applied electric field. Every ferroelectric material has its own unique hysteresis loop reflecting the information of domain reversal under an electric field. In this work, the scaling behaviors of dynamic hysteresis in relaxor (1-x)Pb(Mg_1/3Nb_2/3)O₃-xPbTiO₃ (PMN-PT) ceramics with different compositions were studied systemically. Our results showed that the evolution of scaling behavior in PMN-PT ceramics can be divided into three stages, which is independent of the phase structure of the ceramics and the testing electric field frequency. The relationship between hysteresis area <A> and field amplitude E₀ obeys the power law <A>∝ in the low and high E₀ regions, where the reorientations of 180° and non-180° domain are dominant, respectively. However, the dynamic hysteresis area <A> does not follow the power law in the intermediate E₀ regions, which is attributed to the interaction of different domain reversal mechanisms. Furthermore, the hysteresis area <A> decreases gradually with increasing frequency at a certain E₀ and the time-dependent domain reversal process was also discussed.     

Automated quantized inference for probabilistic programs with AQUA

Innovations in Systems and Software Engineering - We present AQUA, a new probabilistic inference algorithm that operates on probabilistic programs with continuous posterior distributions. AQUA...     

Joining of dense Si3N4 ceramics with tape cast Lu-Al-Si-O-N interlayer

Lu-Al-Si-O-N tapes with different thickness were used to join gas pressure sintered Si₃N₄ ceramics. The microstructure of the joints and the influences of the joint thickness and joining temperature on the bonding strength of the as-joined Si₃N₄ ceramics have been investigated. The highest bonding strength about ~ 300 MPa of the joined specimens was achieved by using 450 µm interlayer at 1450 °C. The existence of Si₃N₄ nanowires was beneficial for the improvement of the bonding strength by interweaving the oxynitride glass matrix in the joint region.     

挥发性有机废气净化技术研究进展

受现代工业的快速发展影响,挥发性有机废气对环境的影响不断提升。基于此,本文将简单分析挥发性有机废气净化技术研究现状,并深入探讨相关研究进展,希望研究内容能够给挥发性有机废气净化技术的选择提供依据。     

Extraction optimisation,antioxidant activity and inhibition on α-amylase and pancreatic lipase of polyphenols from the seeds of Syzygium cumini

The objectives of this study were to determine the optimal extraction conditions of polyphenols from Syzygium cumini seeds by response surface methodology and investigate their antioxidant activity and inhibition on α-amylase and pancreatic lipase. As results, the optimal extraction conditions in the ultrasonic extraction process which maximised total polyphenols content, minimised the IC₅₀ values of α-amylase and pancreatic lipase were determined as follows: extraction time 60 min, ethanol concentration 63% and solvent/solid ratio 44 mL g⁻¹. The main phenolic compounds in partially purified fraction of Syzygium cumini seeds were catechin, epicatechin, kaempferol, gallic, 5-caffeoylquinic, caffeic and ferulic acids. In addition, the partially purified fraction inhibited 87.66 ± 5.55 and 86.61 ± 3.15% of α-amylase and pancreatic lipase, respectively. The results suggested that Syzygium cumini seeds could be explored as a natural antioxidant and could be used as a source of highly antidiabetic and anti-obesity bioactive compounds.     

A Model for Laser Induced Lubricant Depletion in Heat-Assisted Magnetic Recording

The lubricant evaporation caused by the rapid laser heating is always a big concern in heat-assisted magnetic recording. In this article, we develop an empirical equation based on the existing measurement data to describe the relation between the evaporation coefficient of lubricant and temperature on the disk surface. The evaporation coefficient of lubricant is found to decrease from ~1.0 to ~0.003 for the temperature range from 406 to 512 K and follow the trend given by the Arrhenius formula. By incorporating this formula into a previously established evaporation model, we can get a new model, which enables us to predict the lubricant evaporation and depletion caused by the rapid laser heating more accurately than ever.     

光辐射本安设计在光纤传感器中的应用

光纤传感器已被越来越广泛地应用在易燃易爆危险环境中,光辐射防爆设计日趋重要。通过介绍国际电工委员会公布的IEC 60079-28-2006标准,对光辐射点燃机制、防爆保护类型及原理进行了阐述。对连续光辐射和脉冲光辐射的防爆设计准则进行了解析,提出了本质安全光纤传感器的设计思路及系统构架。随着光纤传感器的不断发展和推广,光辐射防爆国家标准的推出,掌握光辐射防爆设计的理论知识及设计准则显得越来越重要。