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Effect of heat treatment on microstructure and mechanical properties of selective laser-melted PH13-8Mo stainless steel

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Journal of Iron and Steel Research(International) 2024年第4期31卷 945-955页

作者： Yuan Zhang Xiang Liu chang-jun Wang chang Liu School of Material Science and Engineering Kunming University of Science and TechnologyKunming 650093YunnanChina Central Iron&Steel Research Institute Co. Ltd.Beijing 100081China

PH13-8Mo stainless steel powder with high sphericity and well fluidity was prepared by the plasma rotating electrode process.The formed parts with ultra-high purity were manufactured by selective laser melting.The tensile and impact mechanical properties of the printed parts under three heat treatment regimes were compared to those without heat treatment.The microstructure,grain orientation and phase composition were characterized by electron-backscatter diffraction,X-ray diffraction and transmission electron microscopy.The characterization results reveal that the addition of heat treatment makes the grains enlarge,and after different heat treatments,the average grain size from 1.51μm in the printed state increases to 2.78,3.09 and 2.06μm,respectively.The formed parts are mainly composed of martensite and retained austenite.Moreover,the NiAl and M23C precipitates form,which are the major strengthening phases of PH13-8Mo stainless steel.The optimal heat treatment process is 925℃×1 h water cooling(WC)+0℃×2 h air cooling(AC)+540℃×4 h AC.Using this heat treatment process,PH13-8Mo formed parts have the optimal comprehensive mechanical properties:the tensile strength,yield strength and impact energy KU2 are 1492 MPa,1432 MPa and 63 J,respectively.The strengthening and toughening via heat treatment are mainly attributed to dislocation strengthening,the formation of NiAl and M23Co precipitates and the change of volume fraction of the retained austenite.

关键词： High-strength stainless steel-Selective laser melting-Heat treatment Microstructure Mechanical property

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A toroidal SAW gyroscope with focused IDTs for sensitivity enhancement

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Microsystems & Nanoengineering 2024年第2期10卷 47-56页

作者： Lu Tian Haitao Zhao Qiang Shen Honglong chang Ministry of Education Key Laboratory of Micro and Nano Systems for Aerospace School of Mechanical EngineeringNorthwestern Polytechnical UniversityXi’an710072China

A surface acoustic wave(SAW)gyroscope measures the rate of rotational angular velocity by exploiting a phenomenon known as the SAW gyroscope effect.Such a gyroscope is a great candidate for application in harsh environments because of the simplification of the suspension vibration mechanism necessary for traditional microelectromechanical system(MEMS)gyroscopes.Here,for the first time,we propose a novel toroidal standing-wave-mode SAW gyroscope using focused interdigitated transducers(FIDTs).Unlike traditional SAW gyroscopes that use linear IDTs to generate surface acoustic waves,which cause beam deflection and result in energy dissipation,this study uses FIDTs to concentrate the SAW energy based on structural features,resulting in better focusing performance and increased SAW amplitude.The experimental results reveal that the sensitivity of the structure is 1.51µV/(°/s),and the bias instability is 0.77°/s,which are improved by an order of magnitude compared to those of a traditional SAW gyroscope.Thus,the FIDT component can enhance the performance of the SAW gyroscope,demonstrating its superiority for angular velocity measurements.This work provides new insights into improving the sensitivity and performance of SAW gyroscopes.

关键词： angular deflection gyroscope

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Generic Modeling and Control Framework for Power Systems Dominated by Power Converters Connected Through a Passive Transmission and Distribution Grid

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 292-301页

作者： Qing-chang Zhong Marcio Stefanello Department of Electrical and Computer Engineering Illinois Institute of TechnologyChicagoIL 60616USA Syndem LLC USA.M.Stefanello is with the Fundacao Universidade Federal do Pampa at AlegreteRS97546-550Brazil

In this paper,a compact mathematical model having an elegant structure,together with a generic control framework,are proposed for generic power systems dominated by power converters that are interconnected through a passive transmission and distribution(T&D)grid,by adopting the port-Hamiltonian(pH)systems theory and the fundamental circuit theory.The models of generic T&D lines are developed and then the model of a generic T&D grid is established.With the proposed control framework,the controlled converters are proven to be passive and Input-to-State Stable(ISS).The compact mathematical model is scalable and can be applied to power systems with multiple power electronic converters with generic passive controllers,passive local loads,and different types of passive T&D lines connected in a meshed configuration without self-loops,so it is very generic.Moreover,the resulting power system is proven to be ISS as well.The analysis is carried out without assumptions on constant frequency/voltage,constant loads,and/or lossless networks,except the need of passivity for all parts involved,and without using the Clarke/Park transformations or the graph theory.To simplify the presentation,three-phase balanced systems are adopted but the results can be easily adapted for single-phase or unbalanced three-phase systems.

关键词： Input-to-State Stable(ISS) passivity,portHamiltonian(pH)systems Power electronic converters dominated power systems Synchronized and Democratized(SYNDEM)grid architecture

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Turning point of organoid transplantation:first-in-human trial of iPSC-derived retinal organoid grafting in patients with retinitis pigmentosa

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Science China(Life Sciences) 2024年第5期67卷 1082-1084页

作者： chang-Jun Zhang Zi-Bing Jin Beijing Institute of Ophthalmology Beijing Tongren HospitalCapital Medical UniversityBeijing 100730China

The discovery of induced pluripotent stem cells(iPSCs)has revolutionized the field of disease research,providing a promising platform for studying various conditions.Over the last decade,significant progress has been made in combining iPSCs with other cutting-edge technologies to investigate disease mechanisms and develop potential treatments.

关键词： conditions patients retinitis

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Use of artificial intelligence in the field of pain medicine

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World Journal of Clinical Cases 2024年第2期12卷 236-239页

作者： Min Cheol chang Department of Physical Medicine and Rehabilitation College of MedicineYeungnam UniversityDaegu 705-717South Korea

In this editorial we comment on the article“Potential and limitations of ChatGPT and generative artificial intelligence in medial safety education”published in the recent issue of the World Journal of Clinical Cases.This article described the usefulness of artificial intelligence(AI)in medial safety education.Herein,we focus specifically on the use of AI in the field of pain medicine.AI technology has emerged as a powerful tool,and is expected to play an important role in the healthcare sector and significantly contribute to pain medicine as further developments are made.AI may have several applications in pain medicine.First,AI can assist in selecting testing methods to identify causes of pain and improve diagnostic accuracy.Entry of a patient’s symptoms into the algorithm can prompt it to suggest necessary tests and possible diagnoses.Based on the latest medical information and recent research results,AI can support doctors in making accurate diagnoses and setting up an effective treatment plan.Second,AI assists in interpreting medical images.For neural and musculoskeletal disorders,imaging tests are of vital importance.AI can analyze a variety of imaging data,including that from radiography,computed tomography,and magnetic resonance imaging,to identify specific patterns,allowing quick and accurate image interpretation.Third,AI can predict the outcomes of pain treatments,contributing to setting up the optimal treatment plan.By predicting individual patient responses to treatment,AI algorithms can assist doctors in establishing a treatment plan tailored to each patient,further enhancing treatment effectiveness.For efficient utilization of AI in the pain medicine field,it is crucial to enhance the accuracy of AI decision-making by using more medical data,while issues related to the protection of patient personal information and responsibility for AI decisions will have to be addressed.In the future,AI technology is expected to be innovatively applied in the field of pain medicine.The advancement of AI is anticipa

关键词： Artificial intelligence Pain medicine Diagnosis Prediction Image

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Chronic venous insufficiency, could it be one of the missing pieces in the puzzle of treating pain?

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World Journal of Clinical Cases 2024年第1期12卷 232-235页

作者： Min Cheol chang Department of Physical Medicine and Rehabilitation Yeungnam University HospitalDaegu 705-717South Korea

Pain is a common complaint among patients seeking medical care.If left un-treated,pain can become chronic,significantly affecting patients’quality of life.An accurate diagnosis of the underlying cause of pain is crucial for effective treatment.Chronic venous insufficiency(CVI)is frequently overlooked by pain physicians.Moreover,many pain physicians lack sufficient knowledge about CVI.CVI is a common condition resulting from malfunctioning or damaged valves in lower limb veins.Symptoms of CVI,ranging from mild to severe,include pain,heaviness,fatigue,itching,swelling,skin color changes,and ulcers in the lower limbs.Recently,it has become more widely known that these symptoms can be attributed to CVI.Even slight or mild CVI can cause related symptoms.Pain physicians primarily consider neuromusculoskeletal disorders when assessing patients with leg pain,and often neglect the possibility of CVI.In clinical practice,when pain physicians encounter patients with unresolved leg pain,they must assess whether the patients exhibit symptoms of CVI and conduct tests to differ-entiate CVI from other potential causes.

关键词： Pain Chronic venous insufficiency Diagnosis Treatment Vein

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基于IEC 61850的微网能量管理系统数据通信模型及其验证

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电力系统自动化 2016年第17期40卷 210-216页

作者：茆美琴张剑张榴晨徐海波教育部光伏系统工程研究中心合肥工业大学安徽省合肥市230009 广东省易事特电源股份有限公司广东省东莞市523808

将IEC 61850系列标准应用于微网能量管理系统,可以规范、统一微网能量管理系统中的通信标准,解决不同厂商制造的设备间的互操作问题。文中将微网通信体系分为三层,详细设计了各层的体系结构及对应的IEC 61850服务器和IEC 61850客户端。... 详细信息

将IEC 61850系列标准应用于微网能量管理系统,可以规范、统一微网能量管理系统中的通信标准,解决不同厂商制造的设备间的互操作问题。文中将微网通信体系分为三层,详细设计了各层的体系结构及对应的IEC 61850服务器和IEC 61850客户端。根据IEC 61850标准建模规范和实时数据在能量管理系统中的应用特点,提出了面向分布式电源整体系统或负荷单元系统来建立微网底层设备的信息模型,并以风力发电单元为例介绍了建模过程。针对所建立的数据模型设计了4个实验,从不同的角度对微网各层通信体系结构下的信息交互进行了实际测试。测试结果验证了所建立信息体系和微网IEC 61850模型的有效性,同时为数据交换模式的优化提供了基础,为微网的设备集成、运行分析及智能控制提供了有效的技术手段。

关键词：微网(微电网) 能量管理系统 IEC 61850 信息模型

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基于解析计算的CSC-PMSG-WGS控制器PI参数设计

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电工技术学报 2017年第20期32卷 205-212页

作者：茆美琴张中洋丁勇张榴晨教育部光伏系统工程研究中心(合肥工业大学) 合肥230009

在基于电流源型变换器的永磁同步风力发电系统(CSC-PMSG-WGS)控制中,比例积分(PI)控制依然是广泛采用的基本控制方法。传统PI参数设计方法由于采用诸多近似计算而使得设计结果不准确,或是由于采用智能优化算法进行参数自动寻优导致PI参... 详细信息

在基于电流源型变换器的永磁同步风力发电系统(CSC-PMSG-WGS)控制中,比例积分(PI)控制依然是广泛采用的基本控制方法。传统PI参数设计方法由于采用诸多近似计算而使得设计结果不准确,或是由于采用智能优化算法进行参数自动寻优导致PI参数的设计方法不通用。为了综合考虑系统中控制器PI参数设计的准确性和简便性,提出一种基于解析计算的设计方法。该方法首先在分析考虑工程实际情况的控制系统传递函数基础上,推导出控制器PI参数解析计算表达式;然后按照系统性能要求及系统参数确定计算式中的关键待定参数进而得到PI参数的值;最后,针对10k W CSC-PMSG-WGS系统实例,分析采用该方法的PI参数详细设计过程。仿真和实验结果证明了采用所提控制器参数设计方法能够有效减少控制器参数设计工作量,并且取得良好的动态和稳态控制性能。

关键词：电流源型变换器永磁同步发电机直驱风力发电系统比例积分参数设计

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Ionic Liquid-Enhanced Assembly of Nanomaterials for Highly Stable Flexible Transparent Electrodes

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Nano-Micro Letters 2024年第7期16卷 441-455页

作者： Jianmin Yang Li chang Xiqi Zhang Ziquan Cao Lei Jiang Key Laboratory of Bio-Inspired Materials and Interfacial Science Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China College of Chemistry and Chemical Engineering Chongqing University of TechnologyChongqing 400054People’s Republic of China Binzhou Institute of Technology Binzhou 256600People’s Republic of China Nanomics Biotechnology Co. Ltd.HangzhouPeople’s Republic of China

The controlled assembly of nanomaterials has demon-strated significant potential in advancing technological devices.However,achieving highly efficient and low-loss assembly technique for nanomate-rials,enabling the creation of hierarchical structures with distinctive func-tionalities,remains a formidable challenge.Here,we present a method for nanomaterial assembly enhanced by ionic liquids,which enables the fabrication of highly stable,flexible,and transparent electrodes featuring an organized layered structure.The utilization of hydrophobic and non-volatile ionic liquids facilitates the production of stable interfaces with water,effectively preventing the sedimentation of 1D/2D nanomaterials assembled at the interface.Furthermore,the interfacially assembled nanomaterial monolayer exhibits an alternate self-climbing behavior,enabling layer-by-layer transfer and the formation of a well-ordered MXene-wrapped silver nanowire network film.The resulting composite film not only demonstrates exceptional photoelectric performance with a sheet resistance of 9.4Ωsq^(-1) and 93%transmittance,but also showcases remarkable environmental stability and mechanical flexibility.Particularly noteworthy is its application in transparent electromagnetic interference shielding materials and triboelectric nanogenerator devices.This research introduces an innovative approach to manufacture and tailor functional devices based on ordered nanomaterials.

关键词： Ionic liquids Assembly Silver nanowires MXene nanosheets Flexible transparent electrodes

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Environmental arsenic(As)and its potential relationship with endemic disease in southwestern China

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Journal of Environmental Sciences 2024年第5期139卷 46-59页

作者： Donglin Li Hucai Zhang Fengqin chang Lizeng Duan Yang Zhang Institute for Ecological Research and Pollution Control of Plateau Lakes School of Ecology and Environmental ScienceYunnan UniversityKunming 650500China Southwest United Graduate School Kunming 650500China

Many cases of an unknown disease exhibiting the clinical features of limb gangrene,blisters,ulceration,and exfoliation have been reported in Daping village(DV)in southwestern China.However,the pathogenesis is unknown and has puzzled doctors for many years.A preliminary study on heavy metals and symptoms indicated that arsenic might pose the greatest threat to the health of local residents.Here,to explore the sources of and factors influencing arsenic enrichment in DV,whose residents exhibit signs of arsenic poisoning,the As contents in soil,water,and plants were systematically measured.The results indicated high As contents in plant and soil samples obtained from the area,and the source of As may be linked to the weathering of black shale rock.Ingestion of soil and consumption of plants were the two main As exposure pathways among children and adults,respectively,and children exhibited a higher health risk than adults.We presume and emphasize that when extreme drought events occur,humans might face unusual risks resulting from exposure to toxic elements and the direct consumption of highly polluted water.Our study provides a new perspective and sheds light on the environmental geochemistry and health links of this disease.

关键词： Endemic disease Arsenic(As) Risk assessment Black shale Climate change

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