Enhanced superelasticity and reversible elastocaloric effect in nano-grained NiTi alloys with low stress hysteresis

Solid-state cooling technologies have been considered as potential alternatives for vapor compression cooling systems.The search for refrigeration materials displaying a unique combination of pronounced caloric effect,low hysteresis,and high reversibility on phase transformation was very active in recent years.Here,we achieved increase in the elastocaloric reversibility and decrease in the friction dissipation of martensite transformations in the superelastic nano-grained NiTi alloys obtained by cold rolling and annealing treatment,with very low stress hysteresis(6.3 MPa)under a large applied strain(5%).Large adiabatic temperature changes(△T_(max)=16.3 K atε=5%)and moderate COP_(mater)values(maximum COP_(mater)=11.8 atε=2%)were achieved.The present nano-grained NiTi alloys exhibited great potential for applications as a highly efficient elastocaloric material.

Noncovalent cross-linked engineering hydrogel with low hysteresis and high sensitivity for flexible self-powered electronics

In this study,the hydrogel network was reinforced by covalent-like hydrogen bonding,and the strong binding ability of boron-nitrogen coordination served as the main driving force.Among them,acrylamide(AM)and 3-acrylamidophenylboronic acid(AAPBA)were the main body,and the numerous hydroxyl groups in the trehalose(Treh)molecule and other polymer groups formed strong hydrogen bonding interactions to improve the mechanical properties of the PAM/PAAPBA/Treh(PAAT)hydrogel and ensured the simplicity of the synthesis process.The hydrogel possessed high strain at break(1239%),stress(64.7 kPa),low hysteresis(100%to 500%strain,corresponding to dissipation energy from 1.37 to 7.80 kJ/m^(3)),and outstanding cycling stability(retained more than 90%of maximum stress after 200 ten-sile cycles).By integrating carbon nanotubes(CNTs)into PAAT hydrogel(PAATC),the PAATC hydrogel with excellent strain response performance was successfully constructed.The PAATC conductive hydro-gel exhibited high sensitivity(gauge factor(GF)=10.58 and sensitivity(S)=0.304 kPa^(-1)),wide strain response range(0.5%-1000%),fast response time(450 ms),and short recovery time(350 ms),excellent fatigue resistance,and strain response stability.Furthermore,the PAATC-based triboelectric nanogener-ator(TENG)displayed outstanding energy harvesting performance,which shows its potential for appli-cation in self-powered electronic devices.

A Selective‑Response Hypersensitive Bio‑Inspired Strain Sensor Enabled by Hysteresis Effect and Parallel Through‑Slits Structures

Flexible strain sensors are promising in sensing minuscule mechanical signals,and thereby widely used in various advanced fields.However,the effective integration of hypersensitivity and highly selective response into one flexible strain sensor remains a huge challenge.Herein,inspired by the hysteresis strategy of the scorpion slit receptor,a bio-inspired flexible strain sensor(BFSS)with parallel through-slit arrays is designed and fabricated.Specifically,BFSS consists of conductive monolayer graphene and viscoelastic styrene–isoprene–styrene block copolymer.Under the synergistic effect of the bio-inspired slit structures and flexible viscoelastic materials,BFSS can achieve both hypersensitivity and highly selective frequency response.Remarkably,the BFSS exhibits a high gage factor of 657.36,and a precise identification of vibration frequencies at a resolution of 0.2 Hz through undergoing different morphological changes to high-frequency vibration and low-frequency vibration.Moreover,the BFSS possesses a wide frequency detection range(103 Hz)and stable durability(1000 cycles).It can sense and recognize vibration signals with different characteristics,including the frequency,amplitude,and waveform.This work,which turns the hysteresis effect into a"treasure,"can provide new design ideas for sensors for potential applications including human–computer interaction and health monitoring of mechanical equipment.

Reducing voltage hysteresis of metal oxide anodes to achieve high energy efficiency for Li-ion batteries

In the past two decades,a lot of high-capacity conversion-type metal oxides have been intensively studied as alternative anode materials for Li-ion batteries with higher energy density.Unfortunately,their large voltage hysteresis(0.8-1.2 V) within reversed conversion reactions results in huge round-trip inefficiencies and thus lower energy efficiency(50%-75%) in full cells than those with graphite anodes.This remains a long-term open question and has been the most serious drawback toward application of metal oxide anodes.Here we clarify the origins of voltage hysteresis in the typical SnO2anode and propose a universal strategy to minimize it.With the established in situ phosphating to generate metal phosphates during reversed conversion reactions in synergy with boosted reaction kinetics by the added P and Mo,the huge voltage hysteresis of 0.9 V in SnO_(2),SnO_(2)-Mo,and 0.6 V in SnO2-P anodes is minimized to 0.3 V in a ternary SnO_(2)-Mo-P(SOMP) composite,along with stable high capacity of 936 mA h g^(-1)after 800 cycles.The small voltage hysteresis can remain stable even the SOMP anode operated at high current rate of10 A g^(-1)and wide-range temperatures from 60 to 30℃,resulting in a high energy efficiency of88.5% in full cells.This effective strategy to minimize voltage hysteresis has also been demonstrated in Fe2O3,Co3O4-basded conversion-type anodes.This work provides important guidance to advance the high-capacity metal oxide anodes from laboratory to industrialization.

Hysteresis loss free soft magnetic ferrites based on Larmor precession

A big enough transverse magnetic field applied to soft magnetic ferrite toroid can magnetize the ferrite to a saturation level in transverse direction and almost completely suppresses magnetic domain structures in the ferrite,the response to the longitudinal alternating electromagnetic field changes from the original domain wall displacements and spin rotations to the precession of magnetization around the transverse field,and the hysteresis loss disappears in the ferrites.Both theoretical and experimental results indicate that the permeability and magnetic loss in the ferrite can be controlled by adjusting the transverse magnetic field.A higher Q value with relatively low permeability can be achieved by increasing the transverse field,which ensures that the ferrite can be operated at high frequencies,with magnetic loss being very low.

A precision-drive hysteresis model with an equal-density weight function for GMA feedforward compensation

Giant magnetostrictive actuators(GMAs) are a widely used type of micro-nano actuator, and they are greatly significant in the field of precision engineering. The accuracy of a GMA often depends on its hysteresis model. However, existing models have some limitations,including the difficulty of identifying their parameters and the tradeoff between the quantity of modeling data required and the level of precision achieved. To solve these problems, in this paper, we propose a Preisach inverse model based on equal-density segmentation of the weight function(E-Preisach). The weight function used to calculate the displacement is first discretized. Then, to obtain a finer weight distribution, the discretized geometric units are uniformly divided by area. This can further minimize the output displacement span, and it produces a higher-precision hysteresis model. The process of parameter identification is made easier by this approach, which also resolves the difficulty of obtaining high precision using a small amount of modeling data. The Preisach and the E-Preisach inverse models were investigated and compared using experiments. At frequencies of 1 and 5 Hz, it was found that the E-Preisach inverse model decreases the maximum error of the feedforward compensation open-loop control to within 1 μm and decreases the root-mean-square error in displacement to within0.5 μm without the need to increase the number of measured hysteresis loops. As a result, the E-Preisach inverse model streamlines the structure of the model and requires fewer parameters for modeling. This provides a high-precision modeling method using a small amount of modeling data;it will have applications in precision engineering fields such as active vibration damping and ultra-precision machining.

Supreme Theory of Everything: The Fundamental Forces in Quantum Hysteresis

Gravity is considered one of the most mysterious of the four fundamental forces, a well-studied but poorly understood phenomenon in science. Newtonian physics and General Relativity have studied it from outside. Based on fundamental forces the Grand Unified Theory (GUT) and the Standard Model (SM) of Particle Physics study from the inside. GUT and SM explain three fundamental forces that govern the universe: electromagnetism, the strong force, and the weak force. The fourth fundamental force hopes that must be gravity, which the SM cannot adequately explain. The research aims to explain fundamental forces and their interactions based on the hysteresis law. The hysteresis law studies the fundamental forces from both inside and outside, so, I hope it can explain the rules and principles of the universe from the microworld to the macroscopic world. The united force of the three fundamental forces in high energy singularity (vertical asymptote) of the hysteresis becomes the weakest like weak interaction and continuously like strong force but has an infinite range like electromagnetic interaction. In this sense, it may be called gravity. Unfortunately, gravity is not an individual force;it is the positive singularity or high energy asymptotic sum of three fundamental forces emerging from the depth of the hysteresis of the subatomic particles.

Modulating J-V hysteresis of planar perovskite solar cells and mini-modules via work function engineering

Commercialization of perovskite solar cells(PSCs) requires the development of high-efficiency devices with none current density-voltage(J-V) hysteresis. Here, electron transport layers(ETLs) with gradual change in work function(WF) are successfully fabricated and employed as an ideal model to investigate the energy barriers, charge transfer and recombination kinetics at ETL/perovskite interface. The energy barrier for electron injection existing at ETL/perovskite is directly assessed by surface photovoltage microscopy, and the results demonstrate the tunable barriers have significant impact on the J-V hysteresis and performance of PSCs. By work function engineering of ETL, PSCs exhibit PCEs over 21% with negligible hysteresis. These results provide a critical understanding of the origin reason for hysteresis effect in planar PSCs, and clear reveal that the J-V hysteresis can be effectively suppressed by carefully tuning the interface features in PSCs. By extending this strategy to a modified formamidinium-cesium-rubidium(FA-Cs-Rb) perovskite system, the PCEs are further boosted to 24.18%. Moreover, 5 cm × 5 cm perovskite mini-modules are also fabricated with an impressive efficiency of 20.07%, demonstrating compatibility and effectiveness of our strategy on upscaled devices.

一类微分项中含Hysteresis的抛物型方程

本文通过引入导出算子分离 Hysteresis与微分 ,证明了一个微分项中含Hysteresis的抛物型方程古典解的存在唯一性 .

运动心电图试验ST/HR滞后(Hysteresis)与冠心病之间关系的研究

目的 探讨平板心电图运动试验ST/HR滞后与冠心病之间的关系及临床意义。方法 对可疑冠心病的136例患者在1周之内分别进行了平板运动试验和冠状动脉造影检查,并计算出心电图运动试验ST/HR滞后最大值。结果 136例患者,传统的ST段压低标准,阳性者86例,可疑阳性21例,其中真阳性78例;ST/HR滞后标准,阳性者83例,真阳性75例。传统的ST段压低标准与ST/HR滞后标准诊断冠心病的敏感性、特异性、准确性分别为714%、862%、758%和903%、868%、890%。结论 平板心电图运动试验ST/HR滞后标准能明显的改进心电图运动试验对冠心病的诊断作用,是检测心肌缺血有价值的指标。

一个主部含Hysteresis的抛物型方程

引入导出算子分离Ｈｙｓｔｅｒｅｓｉｓ与微分，证明了一个主部含Ｈｙｓｔｅｒｅｓｉｓ的抛物型方程古典解的存在唯一性。

一个具Hysteresis的电报方程（英文）

讨论一个具Hysteresis的电报方程.首先给出Ishlinskiǐhysteresis算子的一些性质,然后得到这个方程C1+α,α强解存在性.

一个具Hysteresis的拟线性抛物方程

讨论一个具Hysteresis的电报方程。首先给出了Ishlinskiǐ hysteresis算子的一些性质,然后得到了这个方程C1+α,α强解存在性。

两个具有Hysteresis的发展方程(英文)

研究如下两个具有Hysteresis的发展方程 :utt-Δu +F(u) =f,ut- (F(ux) ) x=f.通过引进Hysteresis算子的逆 ,证明了第一个方程一维初值问题古典解和多维初边值问题强解的存在惟一性以及第二个方程一维初边值问题光滑强解的存在性 .

一个具有Hysteresis的双曲方程(英文)

讨论了一个具有 Hysteresis的双曲方程 。

低温固体界面间接触导热“hysteresis”现象的研究

文中以强化低温固体界面间的接触导热为出发点 ,实验测定了低温环境下两种金属界面在过度加载前后的接触热导值 ,指出过度加载是一种经济有效的强化导热方法 ,对卸载过程接触热导率大于同次加载过程接触热导的“hysteresis”

一个含Hysteresis两相Stefan问题

考虑了一个具有表面张力、动力条件和 Hysteresis的两相 Stefan问题 ,并得到这个问题关于时间的局部古典存在唯一性。

一个含Hysteresis的波动方程

讨论了IshIinskiǐhysteresis算子的性质,给出了一个具弹塑性阻尼的波动方程的古典解存在唯一性.

一类含hysteresis的自控系统模型

很多自控系统都存在时滞效应,描述有害物质反应扩散过程的数学模型就是某种含时滞的微分方程。由于迟滞因子的非线性特性,如函数的许多优良性质被破坏,使得许多具有迟滞特性的模型几乎无法进行分析,因此在一般自控系统的建模中,人们都略去时滞因素。首先根据空气净化系统的功能原理引进了一类时滞算子,通过一系列细致分析给出了时滞算子的若干重要性质。然后主要利用不动点定理证明了含时滞的微分方程整体古典解存在唯一性,最后提出了精细地测算净化设备投资与效益的决策模型。

一个主部含Hysteresis的两相Stefan问题

考虑一个具有表面张力和动力条件，且主部含有Ｈｙｓｔｅｒｅｓｉｓ的两相Ｓｔｅｆａｎ问题，并得到这个问题关于时间的局部古典解存在唯一性。