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Characteristics of metal magnetic memory signals of different steels under static tension

Yiliang ZHANG, Ruibin GOU, Jimin LI, Gongtian SHEN,

《机械工程前沿（英文）》 2010年第5卷第2期页码 226-232 doi: 10.1007/s11465-010-0012-2

摘要： To study the characteristics of metal magnetic memory (MMM) signals of different steels during tensile test, static tension tests were applied to 30 pieces of Q235 and 16MnR base metal and welded specimens. During the various deformation periods, MMM signals are tested, and micrometallographic is observed. Furthermore, the derivative of magnetic intensity (d/d) is analyzed by mathematical and statistical methods to study the macro and micro corresponding relationships and difference among magnetic signals. Results show that despite the different magnetic intensity () curves of different materials, their d/d patterns in the yielding and necking stages are the same; welded specimens have the similar magnetic signal curves with their base metal, and the welded structure does not interfere with its distribution; different materials have their unique zero point (＝0) before being fractured, which is independent of the fracture location; there is a direct relationship between the intragranular slip and the changes of magnetic signals, which indicates the uneven plastic deformation.

关键词： metal magnetic memory (MMM) magnetic intensity (H_p) static tension weld

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Application of metal magnetic memory test in failure analysis and safety evaluation of vessels

Yiliang ZHANG, Song YANG, Xuedong XU

《机械工程前沿（英文）》 2009年第4卷第1期页码 40-48 doi: 10.1007/s11465-009-0003-3

摘要： Metal magnetic memory test (MMMT), which is a new subject in the field of nondestructive examination, can determine regions of stress concentration by testing the distribution of the magnetic field of metal structures so as to effectively diagnose premature defects. MMMT and other test methods are applied in the study to put a propylene purifier of a temperature-jump accident and a leaked ammonia vessel through safety evaluation. Results are as follows: The margin of safety declines after the purifier is overburnt; several stress concentrations are observed within the overburnt area and the level of stress concentration rises after one-month operation; and overpressure operation of the purifier must be strictly avoided and carefully monitored during later operation. Cracks are observed on the ammonia vessel after one year’s service. Extremely high residual stress is the primary cause of cracks. After four years in service, the residual stresses existing in the area of the base metal and weld zone are still greater than 0.5 , which results in numerous cracks due to stress corrosion. From the MMMT result of the ammonia vessel’s defects, it can be seen that the derivative of magnetic density (d p/d ) is an important reference variable. Within the 31 leakage points, 67.7% of them whose dHp/dx values are more than 10, and 96.8% of them whose dHp/dx values are more than 8.

关键词： Metal magnetic memory test (MMMT) nondestructive testing (NDT) residual stress propylene purifier ammonia vessel

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Selective targeted adsorption and inactivation of antibiotic-resistant bacteria by Cr-loaded mixed metal

《环境科学与工程前沿（英文）》 2022年第16卷第6期 doi: 10.1007/s11783-021-1502-7

摘要：

• LDHs and MMOs was synthesized by ultrasound-assisted one-step co-precipitation.

关键词： Heavy metal adsorption Magnetic hydrotalcite ARBs removal Cr(VI)-MMOs combined antibacterial activity

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参与中文配对词语联想学习记忆的脑区和神经机制——脑功能磁共振的研究

郑金龙,舒斯云,刘颂豪,郭周义,吴永明,包新民, 张增强,金梅,马翰章

《中国工程科学》 2008年第10卷第5期页码 38-45

摘要：

通过脑功能磁共振技术，研究健康人参与语言的词语配对联想学习记忆任务的脑区和神经机制。对16名右利手健康志愿者进行一项词语配对联想学习记忆任务作业的同时，进行脑功能磁共振扫描。实验采用组块设计，实验任务（包括记忆编码相和记忆提取相）与对照任务（共两个相）交替进行；数据采用SPM99软件进行数据分析和脑功能区定位。结果表明：左侧额叶，特别是左侧额叶的额中下回和枕叶的18，19区在词语联想学习记忆的编码阶段中起重要作用；而左侧顶上小叶、缘上回和角回则在进行记忆提取阶段起重要作用；左侧纹状体边缘区参与了人脑词语联想学习记忆作业的编码阶段。揭示了人大脑完成语言联想学习记忆任务时，除额、顶、枕和颞叶的皮层结构参与外，还新发现有皮层下结构如纹状体参与了词语联想学习记忆。在配对词语的编码和提取阶段，激活的脑区有所变化，显示了这两个语言阶段的神经活动变化机制。

关键词：人脑功能磁共振配对词语语言联想学习记忆皮层和皮层下结构

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磁力金属带传动中传动比的影响因素分析

罗善明,缪协兴

《中国工程科学》 2002年第4卷第3期页码 73-77

摘要：

对新型磁力金属带传动中传动比的影响因素，如有效牵引力、初张力、磁感应强度、中心距、小带轮直径及围包角等进行了分析和数值模拟，揭示了传动比随这些影响因素而变化的规律。结果表明，磁力金属带传动的传动比随磁感应强度、初张力及中心距的增大而增大，随围包角及小带轮直径的增大而减小。文中指出，由于磁力的作用，小带轮直径及其围包角均可相应减小，因此，其传动比较普通带传动可增加3～4倍。

关键词：带传动磁力金属带传动比

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磁力金属带传动的传动特性分析

罗善明,郭迎福,陈安华,余以道,陈立锋

《中国工程科学》 2005年第7卷第7期页码 76-80

摘要：

介绍了磁力金属带传动的工作原理，分析和探讨了其有效拉力、线速度及弹性滑动率等传动性能，并通过实验测定了相关性能参数。结果表明，磁力金属带传动主要是利用磁场吸引力与初拉力的耦合作用来增加摩擦力进而传递运动和动力的，其传动效率可达95%～98%，而弹性滑动率一般在0.1%以下。

关键词：带传动金属带磁场吸引力机电耦合

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An extended thermo-mechanically coupled algorithm for simulation of superelasticity and shape memoryeffect in shape memory alloys

S. HASHEMI,H. AHMADIAN,S. MOHAMMADI

《结构与土木工程前沿（英文）》 2015年第9卷第4期页码 466-477 doi: 10.1007/s11709-015-0300-3

摘要： Thermo-mechanical coupling in shape memory alloys is a very complicated phenomenon. The heat generation/absorption during forward/reverse transformation can lead to temperature-dependent variation of its mechanical behavior in the forms of superelasticity and shape memory effect. However, unlike the usual assumption, slow loading rate cannot guarantee an isothermal process. A two-dimensional thermo-mechanically coupled algorithm is proposed based on the original model of Lagoudas to efficiently model both superelasticity and shape memory effects and the influence of various strain rates, aspect ratios and boundary conditions. To implement the coupled model into a finite element code, a numerical staggered algorithm is employed. A number of simulations are performed to verify the proposed approach with available experimental and numerical data and to assess its efficiency in solving complex SMA problems.

关键词： shape memory alloy thermo-mechanical coupling superplasticity shape memory effect

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SERS nanoprobes for bio-application

Han-Wen Cheng,Jin Luo,Chuan-Jian Zhong

《化学科学与工程前沿（英文）》 2015年第9卷第4期页码 428-441 doi: 10.1007/s11705-015-1536-0

摘要： The ability to tune the size, shape, composition and surface properties impart nanoparticles with the desired functions for bio-application. This article highlights some of the recent examples in the exploration of metal (e.g., gold and silver) nanoparticles, especially those with magnetic properties and bio-conjugated structures, as theranostic nanoprobes. Such nanoprobes exhibit tunable optical, spectroscopic, magnetic, and electrical properties for signal amplifications. Examples discussed in this article will focus on the nanoproble-enhanced colorimetric detection and surface enhanced Raman scattering (SERS) detection of biomarkers or biomolecules such as proteins and DNAs. The understanding of factors controlling the biomolecular interactions is essential for the design of SERS nanoprobes with theranostic functions.

关键词： surface-enhanced Raman scattering functional nanoprobes bio-conjugation metal nanoparticles magnetic properties theranostic materials

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Modeling and analysis of magnetic dipoles in weak magnetic field

WANG Zhaoxia, ZHANG Weimin, LIU Hongguang

《机械工程前沿（英文）》 2008年第3卷第2期页码 222-225 doi: 10.1007/s11465-008-0028-z

摘要： The magnetic leakage field distribution resulting from linear defects of a tube sample in the geomagnetic field is modeled according to the magnetic dipole theory. The formula to compute the normal component of the weak magnetic field is deduced based on the spatial distribution of the magnetic dipole. The shape and characteristics of the zero line (an important criterion for magnetic memory testing) of the normal field is analyzed under different longitudinal magnetizations. Results show that the characteristics of the zero line should be considered when the metal magnetic memory testing method is used to find and locate the defect.

关键词： geomagnetic theory important criterion magnetic leakage normal component

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Hyperglycemic memory in diabetic cardiomyopathy

《医学前沿（英文）》 2022年第16卷第1期页码 25-38 doi: 10.1007/s11684-021-0881-2

摘要： Cardiovascular diseases account for approximately 80% of deaths among individuals with diabetes mellitus, with diabetic cardiomyopathy as the major diabetic cardiovascular complication. Hyperglycemia is a symptom that abnormally activates multiple downstream pathways and contributes to cardiac hypertrophy, fibrosis, apoptosis, and other pathophysiological changes. Although glycemic control has long been at the center of diabetes therapy, multicenter randomized clinical studies have revealed that intensive glycemic control fails to reduce heart failure-associated hospitalization and mortality in patients with diabetes. This finding indicates that hyperglycemic stress persists in the cardiovascular system of patients with diabetes even if blood glucose level is tightly controlled to the normal level. This process is now referred to as hyperglycemic memory (HGM) phenomenon. We briefly reviewed herein the current advances that have been achieved in research on the underlying mechanisms of HGM in diabetic cardiomyopathy.

关键词： diabetes diabetic cardiomyopathy hyperglycemic memory

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基于分形图案蚀刻屏蔽金属提高磁耦合能量传输效率

Qing-feng LI,Shao-bo CHEN,Wei-ming WANG,Hong-wei HAO,Lu-ming LI

《信息与电子工程前沿（英文）》 2016年第17卷第1期页码 74-82 doi: 10.1631/FITEE.1500114

摘要：薄金属板通常位于磁耦合能量传输（MCET）系统的耦合路径中。金属中的涡流会降低能量传输效率，甚至可能带来安全隐患。本文介绍了在金属中使用蚀刻的分形图案来抑制涡流并提高效率。仿真和实验结果表明该方法非常有效。分形图案应满足三个特征，即，破坏金属边缘，在高强度磁场区域中进行蚀刻以及在厚度方向上贯穿金属进行蚀刻。不同的分形模式导致不同的结果。通过改变涡流分布，当金属表现出电阻效应时，分形图案槽可减少涡流损耗，而当金属表现出电感效应时，分形图案槽可抑制金属中的感应磁场。多层高电导率金属（例如Cu）中的分形图案缝隙显着降低了感应磁场强度。此外，随着蚀刻层数的增加，传递功率，传递效率，接收效率和涡流损耗都增加。这些结果可通过有效的能量传输和在金属屏蔽设备中的安全使用而使MCET受益。

关键词：分形几何；层状金属屏蔽；涡流效应；磁耦合能量传输

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Temperature effects of shape memory alloys (SMAs) in damage control design of steel portal frames

Xiaoqun LUO, Hanbin GE, Tsutomu USAMI

《结构与土木工程前沿（英文）》 2012年第6卷第4期页码 348-357 doi: 10.1007/s11709-012-0176-4

摘要： The objective of the present study is to analytically investigate temperature effects of an axial-type seismic damper made of shape memory alloys (SMAs) equipped in steel frames. Based on a modified multilinear one dimensional constitutive model of SMAs, two types of SMAs are employed, which have different stress plateau and different stress growth rate with temperature increase. Temperature effects of SMA dampers on seismic performance upgrading are discussed in three aspects: different environment temperatures; rapid loading rate induced heat generation and different SMA fractions. The analysis indicates that the effect of environment temperature should be considered for the SMA damper in steel frames. However, the rapid loading rate induced heat generation has little adverse effect.

关键词： damage control design shape memory alloy temperature effect

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A novel shape memory alloy actuated soft gripper imitated hand behavior

《机械工程前沿（英文）》 2022年第17卷第4期 doi: 10.1007/s11465-022-0700-8

摘要： The limited length shrinkage of shape memory alloy (SMA) wire seriously limits the motion range of SMA-based gripper. In this paper, a new soft finger without silicone gel was designed based on pre bent SMA wire, and the finger was back to its original shape by heating SMA wire, rather than relying only on heat exchange with the environment. Through imitating palm movement, a structure with adjustable spacing between fingers was made using SMA spring and rigid spring. The hook structure design at the fingertip can form self-locking to further improve the load capacity of gripper. Through the long thin rod model, the relationship of the initial pre bent angle on the bending angle and output force of the finger was analyzed. The stress-strain model of SMA spring was established for the selection of rigid spring. Three grasping modes were proposed to adapt to the weight of the objects. Through the test of the gripper, it was proved that the gripper had large bending amplitude, bending force, and response rate. The design provides a new idea for the lightweight design and convenient design of soft gripper based on SMA.

关键词： shape memory alloy (SMA) pre bent wire gripper grasping mode lightweight

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A fully solid-state cold thermal energy storage device for car seats using shape-memory alloys

《能源前沿（英文）》 2023年第17卷第4期页码 504-515 doi: 10.1007/s11708-022-0855-3

摘要： Thermal energy storage has been a pivotal technology to fill the gap between energy demands and energy supplies. As a solid-solid phase change material, shape-memory alloys (SMAs) have the inherent advantages of leakage free, no encapsulation, negligible volume variation, as well as superior energy storage properties such as high thermal conductivity (compared with ice and paraffin) and volumetric energy density, making them excellent thermal energy storage materials. Considering these characteristics, the design of the shape-memory alloy based the cold thermal energy storage system for precooling car seat application is introduced in this paper based on the proposed shape-memory alloy-based cold thermal energy storage cycle. The simulation results show that the minimum temperature of the metal boss under the seat reaches 26.2 °C at 9.85 s, which is reduced by 9.8 °C, and the energy storage efficiency of the device is 66%. The influence of initial temperature, elastocaloric materials, and the shape-memory alloy geometry scheme on the performance of car seat cold thermal energy storage devices is also discussed. Since SMAs are both solid-state refrigerants and thermal energy storage materials, hopefully the proposed concept can promote the development of more promising shape-memory alloy-based cold and hot thermal energy storage devices.

关键词： shape-memory alloy (SMA) elastocaloric effect (eCE) cooled seat cold thermal energy storage

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Continuous size fractionation of magnetic nanoparticles by using simulated moving bed chromatography

Carsten-Rene Arlt, Dominik Brekel, Stefan Neumann, David Rafaja, Matthias Franzreb

《化学科学与工程前沿（英文）》 2021年第15卷第5期页码 1346-1355 doi: 10.1007/s11705-021-2040-3

摘要： The size fractionation of magnetic nanoparticles is a technical problem, which until today can only be solved with great effort. Nevertheless, there is an important demand for nanoparticles with sharp size distributions, for example for medical technology or sensor technology. Using magnetic chromatography, we show a promising method for fractionation of magnetic nanoparticles with respect to their size and/or magnetic properties. This was achieved by passing magnetic nanoparticles through a packed bed of fine steel spheres with which they interact magnetically because single domain ferro-/ferrimagnetic nanoparticles show a spontaneous magnetization. Since the strength of this interaction is related to particle size, the principle is suitable for size fractionation. This concept was transferred into a continuous process in this work using a so-called simulated moving bed chromatography. Applying a suspension of magnetic nanoparticles within a size range from 20 to 120 nm, the process showed a separation sharpness of up to 0.52 with recovery rates of 100%. The continuous feed stream of magnetic nanoparticles could be fractionated with a space-time-yield of up to 5 mg/(L∙min). Due to the easy scalability of continuous chromatography, the process is a promising approach for the efficient fractionation of industrially relevant amounts of magnetic nanoparticles.

关键词： magnetic chromatography simulated moving bed chromatography magnetic nanoparticles size fractionation