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点状热干扰源诱导的准各向同性高温超导股线失超特性

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电工技术学报 2024年第2期39卷 369-377页

作者：王起悦刘子秋孙梓源杨宇皮伟华北电力大学新能源电力系统国家重点实验室北京102206 国网山东省电力公司济南供电公司济南250000

第二代高温超导带材因其较高的临界电流密度以及良好的机械特性,近年来在超导研究领域得到极大关注。由REBCO带材组成的高温超导导体在液氮温度下的零电阻特性使其在超导输电领域具有巨大的潜力。从安全角度看,高温超导导体的失超保护... 详细信息

第二代高温超导带材因其较高的临界电流密度以及良好的机械特性,近年来在超导研究领域得到极大关注。由REBCO带材组成的高温超导导体在液氮温度下的零电阻特性使其在超导输电领域具有巨大的潜力。从安全角度看,高温超导导体的失超保护研究是其获得广泛应用的一个关键。该文建立了准各向同性超导股线的三维失超仿真模型,耦合了电场、磁场和温度场,模拟了不同运行电流以及不同点状热干扰能量下超导股线的失超行为,求解出股线的温度、电流密度以及磁场分布,得到了准各向同性高温超导股线的最小失超能(MQE)以及失超传播速度(QPV),对超导装置的失超保护具有重要意义。该文对准各向同性超导股线建立的三维失超模型,也可以应用到其他结构的高温超导导体的失超研究中。

关键词：准各向同性超导股线失超行为最小失超能失超传播速度

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新时代高职院校课堂教学评价改革探析

长沙航空职业技术学院学报 2024年第3期24卷 52-55页

作者：皮卫湖南商务职业技术学院湖南长沙410205

随着教育改革的深入推进,高职院校的教学评价面临着新的机遇和挑战。文章从高职院校课堂教学评价的现状出发,分析了新时代高职院校课堂教学评价改革的必要性和可行性,探讨了一些推动高职院校课堂教学评价改革的具体路径,以及亟需解决的... 详细信息

随着教育改革的深入推进,高职院校的教学评价面临着新的机遇和挑战。文章从高职院校课堂教学评价的现状出发,分析了新时代高职院校课堂教学评价改革的必要性和可行性,探讨了一些推动高职院校课堂教学评价改革的具体路径,以及亟需解决的难点问题,并对未来的发展进行了展望。

关键词：新时代高职院校教学评价改革

粤东连平—河源—汕尾地震测深剖面地壳速度结构及其意义

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地球物理学报 2024年第6期67卷 2304-2321页

作者：叶秀薇吕作勇王亮宋佳佳段永红王帅军宋向辉郑金宝皮伟广东省地震局(中国地震局地震监测与减灾技术重点实验室广东省地震预警与重大工程安全诊断重点实验室)广州510070 中国地震局地球物理勘探中心郑州450002 河南省地球物理空间信息研究院河南省地质物探工程技术研究中心郑州450004

为适应防灾减灾工作的需要,广东省地震局联合中国地震局地球物理勘探中心、河南省地球物理空间信息研究院于2021年在粤东地区实施了人工地震宽角反射/折射探测,以期获得粤东地区深部地壳速度结构.本文采用地震射线走时正演对粤东地区NW... 详细信息

为适应防灾减灾工作的需要,广东省地震局联合中国地震局地球物理勘探中心、河南省地球物理空间信息研究院于2021年在粤东地区实施了人工地震宽角反射/折射探测,以期获得粤东地区深部地壳速度结构.本文采用地震射线走时正演对粤东地区NW向连平—河源—海丰测线数据进行了处理解释,构建了该剖面的二维壳幔速度结构模型.该模型表明,沿剖面自NW向SE,莫霍面深度由32 km缓慢抬升至29 km,广州—恩平断裂带、河源—邵武断裂带和政和—大埔断裂带的对应位置都显示莫霍面有抬升现象;研究区存在多条NE向展布深大断裂;中地壳发育低速异常区域(低速体)受断裂控制,主要分布于政和—大埔断裂带NW内陆方向,可能与中生代早期岩浆活动形成的花岗岩质岩浆相关.我们认为壳内低速区域(低速体)可能是影响研究区深部孕震环境的重要因素.

关键词：华南大陆粤东地区人工地震测深壳幔精细速度结构壳内低速体

Reduced graphene oxide-embedded nerve conduits loaded with bone marrow mesenchymal stem cell-derived extracellular vesicles promote peripheral nerve regeneration

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Neural Regeneration Research 2023年第1期18卷 200-206页

作者： wei Zhang Xing-Xing Fang Qi-Cheng Li wei pi Na Han Department of Orthopedics and Trauma Peking University People’s HospitalBeijingChina National Center for Trauma Medicine BeijingChina Central Laboratory Peking University People’s HospitalBeijingChina

We previously combined reduced graphene oxide(rGO)with gelatin-methacryloyl(GelMA)and polycaprolactone(PCL)to create an rGO-GelMA-PCL nerve conduit and found that the conductivity and biocompatibility were ***,the rGO-GelMA-PCL nerve conduits differed greatly from autologous nerve transplants in their ability to promote the regeneration of injured peripheral nerves and axonal *** vesicles derived from bone marrow mesenchymal stem cells(BMSCs)can be loaded into rGO-GelMA-PCL nerve conduits for repair of rat sciatic nerve injury because they can promote angiogenesis at the injured *** this study,12 weeks after surgery,sciatic nerve function was measured by electrophysiology and sciatic nerve function index,and myelin sheath and axon regeneration were observed by electron microscopy,immunohistochemistry,and *** regeneration of microvessel was observed by *** results showed that rGO-GelMA-PCL nerve conduits loaded with BMSC-derived extracellular vesicles were superior to rGO-GelMA-PCL conduits alone in their ability to increase the number of newly formed vessels and axonal sprouts at the injury site as well as the recovery of neurological *** findings indicate that rGO-GelMA-PCL nerve conduits loaded with BMSC-derived extracellular vesicles can promote peripheral nerve regeneration and neurological function recovery,and provide a new direction for the curation of peripheral nerve defect in the clinic.

关键词： angiogenesis axon bone mesenchymal stem cell extracellular vesicles hybrid nanofibers myelin sheath nerve conduit neurological function peripheral nerve injury reduced graphene oxide

Myelin-associated glycoprotein combined with chitin conduit inhibits painful neuroma formation after sciatic nerve transection

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Neural Regeneration Research 2022年第6期17卷 1343-1347页

作者： wei pi Ci Li Meng Zhang wei Zhang Pei-Xun Zhang Department of Orthopedics and Trauma Peking University People’s HospitalPeking UniversityBeijingChina Key Laboratory of Trauma and Neural Regeneration Peking UniversityBeijingChina National Center for Trauma Medicine BeijingChina

Studies have shown that myelin-associated glycoprotein(MAG)can inhibit axon regeneration after nerve ***,the effects of MAG on neuroma formation after peripheral nerve injury remain poorly *** this study,local injection of MAG combined with nerve cap made of chitin conduit was used to intervene with the formation of painful neuroma after sciatic nerve transfection in *** 8 weeks of combined treatment,the autotomy behaviors were reduced in rats subjected to sciatic nerve transfection,the mRNA expression of nerve growth factor,a pain marker,in the proximal nerve stump was decreased,the density of regenerated axons was decreased,the thickness of the myelin sheath was increased,and the ratio of unmyelinated to myelinated axons was ***,the percentage of collagen fiber area and the percentage of fibrosis marker alpha-smooth muscle actin positive staining area in the proximal nerve stump were *** combined treatment exhibited superior effects in these measures to chitin conduit treatment *** findings suggest that MAG combined with chitin conduit synergistically inhibits the formation of painful neuroma after sciatic nerve transection and alleviates neuropathic *** study was approved by the Animal Ethics Committee of Peking University People’s Hospital(approval No.2019PHE027)on December 5,2019.

关键词： autotomy axon chitin conduit fibrosis myelin-associated glycoprotein painful neuroma peripheral nerve regeneration

Cortical plasticity and nerve regeneration after peripheral nerve injury

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Neural Regeneration Research 2021年第8期16卷 1518-1523页

作者： Ci Li Song-Yang Liu wei pi Pei-Xun Zhang Department of Orthopedics and Trauma Peking University People’s HospitalBeijingChina Key Laboratory of Trauma and Neural Regeneration Peking UniversityBeijingChina National Center for Trauma Medicine BeijingChina

With the development of neuroscience, substantial advances have been achieved in peripheral nerve regeneration over the past decades. However, peripheral nerve injury remains a critical public health problem because of the subsequent impairment or absence of sensorimotor function. Uncomfortable complications of peripheral nerve injury, such as chronic pain, can also cause problems for families and society. A number of studies have demonstrated that the proper functioning of the nervous system depends not only on a complete connection from the central nervous system to the surrounding targets at an anatomical level, but also on the continuous bilateral communication between the two. After peripheral nerve injury, the interruption of afferent and efferent signals can cause complex pathophysiological changes, including neurochemical alterations, modifications in the adaptability of excitatory and inhibitory neurons, and the reorganization of somatosensory and motor regions. This review discusses the close relationship between the cerebral cortex and peripheral nerves. We also focus on common therapies for peripheral nerve injury and summarize their potential mechanisms in relation to cortical plasticity. It has been suggested that cortical plasticity may be important for improving functional recovery after peripheral nerve damage. Further understanding of the potential common mechanisms between cortical reorganization and nerve injury will help to elucidate the pathophysiological processes of nerve injury, and may allow for the reduction of adverse consequences during peripheral nerve injury recovery. We also review the role that regulating reorganization mechanisms plays in functional recovery, and conclude with a suggestion to target cortical plasticity along with therapeutic interventions to promote peripheral nerve injury recovery.

关键词： cortical plasticity injury mechanisms nerve transfer neurorrhaphy peripheral nerve phantom limb pain recovery regeneration treatment

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某油田联合站注水管道结垢腐蚀失效分析

西部特种设备 2024年第2期7卷 64-68页

作者：陈妍君皮维唐梓喻中国石油西南油气田分公司安全环保与技术监督研究院四川成都610000 中国石油塔里木油田分公司塔中采油气管理区新疆塔里木841000 中国石油西南油气田分公司输气管理处四川成都610000

某油田联合站注水管道一年84.6%的失效由内腐蚀导致。本研究通过灼烧、强酸溶解、射线能谱(EDS)、XRD分析等室内实验方法,对垢样和腐蚀产物进行了分析。结合注水系统工艺、水质成分等条件,分析注水管道失效直接原因为水中溶解的O_(2)、C... 详细信息

某油田联合站注水管道一年84.6%的失效由内腐蚀导致。本研究通过灼烧、强酸溶解、射线能谱(EDS)、XRD分析等室内实验方法,对垢样和腐蚀产物进行了分析。结合注水系统工艺、水质成分等条件,分析注水管道失效直接原因为水中溶解的O_(2)、CO_(2)、H_(2)S电离形成浓差电池;同时油田采出水配伍性差导致的严重结垢和水中高浓度氯离子加剧了腐蚀穿孔。

关键词：油田注水管道结垢内腐蚀失效分析

Induced current of high temperature superconducting loops by combination of exciting coil and thermal switch

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Chinese Physics B 2022年第3期31卷 521-526页

作者： Jia-Wen Wang Yin-Shun Wang Hua Chai Ling-Feng Zhu wei pi State Key Laboratory of New Energy Renewable Power System North China Electric Power UniversityBeijing 102206China

With its commercialization, the second-generation(2G) high temperature superconducting(HTS) RE–Ba–Cu–O(REBCO, RE is rare earth) tape is extensively applied to the superconducting magnets in the high magnetic fields. However,unlike low temperature superconducting(LTS) magnets, the HTS magnet cannot operate in the persistent current mode(PCM) due to the immature superconducting soldering technique. In this paper, an exciting method for two HTS sub-loops,so-called charging and load loops, is proposed by flux pump consisting of exciting coil and controllable thermal *** HTS sub-loops are made of an REBCO tape with two slits. An exciting coil with iron core is located in one sub-loop and is supplied with a triangular waveform current so that magnetic field is generated in another sub-loop. The influence of magnetic flux on induced current in load loop is presented and verified in experiment at 77 K. The relationship between the induced magnetic flux density and the current on the sub-loops having been calibrated, magnetic flux density, and induced current are obtained. The results show that the HTS sub-loops can be excited by a coil with thermal switch and the induced current increases with magnetic flux of exciting coil increasing, which is promising for persistent current operation mode of HTS magnets.

关键词： bridge high temperature superconducting(HTS)sub-loops induced current thermal switch

Analysis of the Self-Protection Characteristics of a 1.5T Bitter-Like HTS Magnet Operated at 65K

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Chinese Physics Letters 2018年第6期35卷 79-83页

作者： Yan-Bing Hou Yin-Shun Wang Chang-Tao Kan Xi Yuan wei pi State Key Laboratory of New Energy Power System North China Electric Power University

We present a conceptual configuration of a high-temperature superconducting（HTS）magnet made from REBCO（Re=Rare Earth,B=Barium,C=Copper,O=Oxide）annular plates,called a Bitter-like HTS magnet,which can operate in persistent current mode without joint resistance and can be excited by a flux pump and without current leads and a persistent power *** REBCO annular magnet which can generate 1.5 T corresponding to the operating current density 80%of critical current density of the magnet at an operating temperature of65 K is conceptually *** the thermal stability of the magnet is numerically simulated by Comsol *** a piece of RBCO annular plate quenches,the maximum released energy is its stored energy because each REBCO annular plate in the Bitter-like magnet is in *** calculate the stored energy in the REBCO annular plate,the inductance of every annular plate,including self-inductance and mutual inductance,is *** with the minimum quench energy（MQE）and stored energy in one REBCO annular plate,the stored energy in one REBCO annular plate is always smaller than the MQE,and the REBCO annular plate will not be damaged even though the stored energy in the REBCO annular plate is fully released,which indicates that this 1.5 T Bitter-like magnet has the property of self-protection.

关键词： REBCO Analysis of the Self-Protection Characteristics of a 1.5T Bitter-Like HTS Magnet Operated at 65K HTS