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基于“课程思政”的基础力学教学实践思考
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作者 李欣业 韩明江 +1 位作者 李晓雷 叶楠 《西南交通大学学报(社会科学版)》 2023年第S02期244-249,共6页
发挥课堂教学在大学生思想政治教育中的主渠道作用,注重挖掘和运用各学科所蕴含的思想政治教育资源,引导大学生树立正确的世界观、人生观和价值观,是我们党在新时代关于“培养什么样的人、如何培养人以及为谁培养人”这个根本问题上对... 发挥课堂教学在大学生思想政治教育中的主渠道作用,注重挖掘和运用各学科所蕴含的思想政治教育资源,引导大学生树立正确的世界观、人生观和价值观,是我们党在新时代关于“培养什么样的人、如何培养人以及为谁培养人”这个根本问题上对高校加强和改进思想政治教育和人才培养的新定位、新要求、新任务。本文以基础力学教学为依托,阐述了可以通过哪些渠道融入课程思政元素并基于此应着力培养哪些能力以及提升哪些素质。本文的观点同样适合于除了基础力学之外的其他课程的“课程思政”;不仅适合本科生教学的“课程思政”也适合于研究生教学的“课程思政”。 展开更多
关键词 基础力学教学 课程思政 能力培养 素质提升
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Zn−Sn−Cu−xNi无铅焊料合金的电化学腐蚀行为
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作者 陈文静 叶楠 +1 位作者 卓海鸥 唐建成 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2023年第9期2740-2750,共11页
通过铸造法制备Zn−30Sn−2Cu−xNi(x=0,0.5,1.0,1.5,质量分数,%)无铅焊料合金,并研究该合金的微观组织演化及在0.5 mol/L NaCl溶液中的腐蚀行为。采用电位动力学极化和电化学阻抗谱(EIS)技术研究其电化学行为,以此评估Ni元素含量对Zn−Sn−C... 通过铸造法制备Zn−30Sn−2Cu−xNi(x=0,0.5,1.0,1.5,质量分数,%)无铅焊料合金,并研究该合金的微观组织演化及在0.5 mol/L NaCl溶液中的腐蚀行为。采用电位动力学极化和电化学阻抗谱(EIS)技术研究其电化学行为,以此评估Ni元素含量对Zn−Sn−Cu合金腐蚀性能的影响。通过观察腐蚀过程中合金表面显微组织的演变,分析Zn−Sn−Cu−Ni合金的腐蚀机理。结果表明,添加0.5%Ni由于形成致密而均匀的腐蚀层从而有效提高Zn−30Sn−2Cu合金的耐腐蚀性能,且其主要腐蚀产物为ZnO,Zn(OH)_(2)和Zn_(5)(OH)_(8)Cl_(2)·H_(2)O。当Ni含量达到1.0%和1.5%时,Zn−30Sn−2Cu合金的耐腐蚀性能下降,主要是由于(Ni,Cu)5Zn21金属间化合物与富Zn相之间的电偶腐蚀加速富Zn相的溶解。因此,Zn−30Sn−2Cu−0.5Ni焊料合金具有最佳的耐腐蚀性能。 展开更多
关键词 Zn−Sn−Cu−Ni合金 显微组织 极化 电化学阻抗谱 电偶腐蚀
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胃镜-X线联合金属内支架置入治疗胃十二指肠恶性梗阻的临床价值 被引量:4
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作者 袁娟 叶楠 +1 位作者 冯凯祥 林卫 《中国内镜杂志》 北大核心 2017年第12期73-76,共4页
目的探讨内镜直视联合X线监视下金属内支架置入治疗胃十二指肠恶性梗阻的临床价值。方法选择2013年1月-2015年12月该院消化内科收治的胃十二指肠恶性梗阻患者70例为研究对象,按照患者住院先后顺序编号,将奇数号患者纳入观察组,偶数号患... 目的探讨内镜直视联合X线监视下金属内支架置入治疗胃十二指肠恶性梗阻的临床价值。方法选择2013年1月-2015年12月该院消化内科收治的胃十二指肠恶性梗阻患者70例为研究对象,按照患者住院先后顺序编号,将奇数号患者纳入观察组,偶数号患者纳入对照组,每组患者35例。两组患者在内科基础治疗的前提下,观察组采用内镜直视联合X线监视下金属内支架置入,对照组采用单纯胃镜引导下金属内支架置入。记录两组患者手术操作时间,支架一次性置入成功率、准确率、覆盖病变、支架脱落/移位及并发症情况,并进行统计学分析。结果平均手术操作时间观察组(9.71±3.60)min,对照组(21.01±5.20)min;支架一次性置入成功率观察组97.14%,对照组77.14%;术后4周复查支架通畅率观察组97.14%,对照组74.28%;覆盖病变两组无明显差别。并发症:两组患者均出现少量出血,经处理后出血停止;观察组未见消化道溃疡,支架移位1例,胃肠道并发症1例,代谢并发症1例;对照组支架移位4例,胃肠道并发症6例,代谢并发症7例。结论胃镜-X线联合金属内支架置入治疗胃十二指肠恶性梗阻操作时间短、置入成功率高、支架定位准确、并发症少,存活时间长,是一种简单可行、安全有效的方法。 展开更多
关键词 胃十二指肠梗阻 内镜 支架
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基于CiteSpace的针刺治疗荨麻疹的可视化分析研究
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作者 南烨 左宇飞 +3 位作者 李娜 梁小卷 郭新荣 王卫刚 《成都中医药大学学报》 2023年第4期69-75,共7页
目的:对国内针刺治疗荨麻疹的文献进行筛选统计和可视化分析,总结这一疾病的发展现状、研究热点及探讨未来的发展趋势。方法:整理中国知网数据库(CNKI)自建库以来针刺治疗荨麻疹的相关文献,运用CiteSpace 6.1R4软件对文献作者、相关机... 目的:对国内针刺治疗荨麻疹的文献进行筛选统计和可视化分析,总结这一疾病的发展现状、研究热点及探讨未来的发展趋势。方法:整理中国知网数据库(CNKI)自建库以来针刺治疗荨麻疹的相关文献,运用CiteSpace 6.1R4软件对文献作者、相关机构、关键词等进行可视化分析研究。结果:共纳入547篇文献,年发文量呈总体上升趋势;发文最多的作者为马铁明和王艳君;广州中医药大学、辽宁中医药大学和成都中医药大学是主要研究机构。研究过程中涉及到的高频关键词有:针刺疗法、荨麻疹、针灸疗法、穴位埋线、拔罐等,并且形成了11个关键词聚类和15个关键词突现。结论:当前研究热点主要集中在3个方面:针刺、穴位埋线等不同方法的疗效评价;曲池、血海、三阴交为代表的选穴规律;针刺调节机体免疫的机制研究。该领域尚需解决的关键在于优化干预措施和探究针刺治疗荨麻疹的作用机理。希望通过此次研究,能够为日后关于针刺治疗荨麻疹案例的分析提供借鉴。 展开更多
关键词 针刺 荨麻疹 可视化分析 CITESPACE
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激光熔覆制备WC-12Co复合涂层的显微组织和性能 被引量:9
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作者 胡妙 唐建成 +3 位作者 陈新贵 叶楠 赵心阅 徐苗苗 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第4期1017-1030,共14页
采用同轴送粉激光熔覆工艺制备WC-12Co复合涂层,并对涂层的相组成、显微组织演变、硬度和磨损性能进行综合研究。结果表明:在高扫描速率和高激光能量密度综合作用下,WC-12Co复合粉末边缘的WC部分溶解于液态Co和304不锈钢基体中,形成层片... 采用同轴送粉激光熔覆工艺制备WC-12Co复合涂层,并对涂层的相组成、显微组织演变、硬度和磨损性能进行综合研究。结果表明:在高扫描速率和高激光能量密度综合作用下,WC-12Co复合粉末边缘的WC部分溶解于液态Co和304不锈钢基体中,形成层片状WC和鱼骨状新型碳化物M3W3C(M=Fe,Co)。所得WC-12Co复合涂层致密化程度高,与基体形成良好的冶金结合,未出现气孔、裂纹和脱碳等缺陷。此外,当激光功率为1500 W时,在良好冶金结合与精细显微组织的综合作用下涂层的维氏硬度和耐磨性能显著提高,硬度达HV0.3 1500~HV0.3 1600,涂层的摩擦因数和磨损率较低,分别为0.55和(2.15±0.3 1)×10-7mm3/(N·m)。 展开更多
关键词 激光熔覆 WC-12Co复合涂层 显微组织演变 显微硬度 磨损性能
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添加剂及纳米WC粉含量对电镀WC-Cu复合材料性能的影响 被引量:1
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作者 赵玉超 唐建成 +3 位作者 叶楠 周威威 韦朝龙 刘定军 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第6期1594-1604,共11页
研究添加剂(聚乙二醇(PEG)、十二烷基硫酸钠(SDS))和纳米WC粉对WC-Cu复合材料显微结构、相对密度、硬度和导电性的影响,并对电镀制备机理进行研究。采用XRD、SEM、EDS、TEM、HRTEM等测试方法分析样品的显微结构。PEG与SDS的协同作用使WC... 研究添加剂(聚乙二醇(PEG)、十二烷基硫酸钠(SDS))和纳米WC粉对WC-Cu复合材料显微结构、相对密度、硬度和导电性的影响,并对电镀制备机理进行研究。采用XRD、SEM、EDS、TEM、HRTEM等测试方法分析样品的显微结构。PEG与SDS的协同作用使WC-Cu复合材料在电镀过程中更加致密。WC-Cu复合材料的硬度随着WC含量的增加而增加,导电性随WC含量的增加而降低。随着添加剂含量的增加,样品的密度呈现先增大后减小的趋势。当电镀液中含有10 g/L WC纳米粉、0.2 g/L PEG和0.1 g/L SDS时,WC-Cu复合材料硬度为HV 221、电导率为53.7 MS/m。结果表明,通过优化添加剂和纳米WC颗粒的含量,可以得到性能优良的WC-Cu复合材料。 展开更多
关键词 WC-Cu复合材料 电镀 添加剂 显微结构 性能
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Development of a human rotavirus induced diarrhea model in Chinese mini-pigs 被引量:3
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作者 Jin-tao Li Jing Wei +5 位作者 Hong-xia Guo Jiang-bo Han nan ye Hai-Yang He tian-tian Yu Yu-zhang Wu 《World Journal of Gastroenterology》 SCIE CAS 2016年第31期7135-7145,共11页
AIM: to establish a new animal model for the research of human rotavirus(HRV) infection, its pathogenesis and immunity and evaluation of potential vaccines.METHODS: 5-d, 30-d and 60-d-old Chinese mini-pigs, Guizhou an... AIM: to establish a new animal model for the research of human rotavirus(HRV) infection, its pathogenesis and immunity and evaluation of potential vaccines.METHODS: 5-d, 30-d and 60-d-old Chinese mini-pigs, Guizhou and bamma, were inoculated with a single oral dose of attenuated strain Wa, G1, G3 of HRV, and PbS(control), respectively, and fecal samples of pigs from 0 to 7 d post infection(DPI) were collected individually. Enzyme linked immunosorbent assay was used to detect HRV antigen in feces. the HRV was tested by real-time PCR(Rt-PCR). the sections of the intestinal tissue were stained with hematoxylin and eosin to observe the morphologic variation by microscopy. Immunofluorescence was used to determine the HRV in intestinal tissue. HRV particles in cells of the ileum were observed by electron micrography.RESULTS: When inoculated with HRV, mini-pigs younger than 30 d developed diarrhea in an agedependent manner and shed HRV antigen of the sameinoculum, as demonstrated by Rt- PCR.Histopathological changes were observed in HRV inoculated mini-pigs including small intestinal cell tumefaction and necrosis. HRV that was distributed in the small intestine was restricted to the top part of the villi on the internal wall of the ileum, which was observed by immunofluorescence and transmission electron microscopy. Virus particles were observed in Golgi like follicles in HRV-infected neonatal minipigs. Guizhou mini-pigs were more sensitive to HRV than bamma with respect to RV antigen shedding and clinical diarrhea.CONCLUSION: these results indicate that we have established a mini-pig model of HRV induced diarrhea. Our findings are useful for the understanding of the pathogenic mechanisms of HRV infection. 展开更多
关键词 Human ROTAVIRUS ANIMAL model CHINESE mini-pigs DIARRHEA INTESTINE
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Sodium chloride exacerbates dextran sulfate sodiuminduced colitis by tuning proinflammatory and antiinflammatory lamina propria mononuclear cells through p38/MAPK pathway in mice 被引量:1
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作者 Hong-Xia Guo nan ye +7 位作者 Ping Yan Min-Yue Qiu Ji Zhang Zi-Gang Shen Hai-Yang He Zhi-Qiang Tian Hong-Li Li Jin-Tao Li 《World Journal of Gastroenterology》 SCIE CAS 2018年第16期1779-1794,共16页
AIM To investigate the influence of high salt on dextran sulfate sodium(DSS)-induced colitis in mice and explore the underlying mechanisms of this effect.METHODS DSS and NaC l were used to establish the proinflammator... AIM To investigate the influence of high salt on dextran sulfate sodium(DSS)-induced colitis in mice and explore the underlying mechanisms of this effect.METHODS DSS and NaC l were used to establish the proinflammatory animal model. We evaluated the colitis severity. Flow cytometry was employed for detecting the frequencies of Th1, macrophages and Tregs in spleen, mesenteric lymph node and lamina propria. The important role of macrophages in the promotion of DSS-induced colitis by NaCl was evaluated by depleting macrophages with clodronate liposomes. Activated peritoneal macrophages and lamina propria mononuclear cells(LPMCs) were stimulated with NaCl, and proteins were detected by western blotting. Cytokines and inflammation genes were analyzed by enzyme-linked immunosorbent assay and RT-PCR, respectively.RESULTS The study findings indicate that NaC l up-regulates the frequencies of CD11b^+ macrophages and CD4^+IFN-γ^+IL-17^+ T cells in lamina propria in DSS-treated mice. CD3^+CD4^+CD25^+Foxp^3+ T cells, which can secrete high levels of IL-10 and TGF-β, increase through feedback in NaCl-and DSS-treated mice. Furthermore, clodronate liposomes pretreatment significantly alleviated DSSinduced colitis, indicating that macrophages play a vital role in NaCl proinflammatory activity. NaCl aggravates peritoneal macrophage inflammation by promoting the expressions of interleukin(IL)-1, IL-6 and mouse inducible nitric oxide synthase. Specifically, high NaCl concentrations promote p38 phosphorylation in lipopolysaccharide-and IFN-γ-activated LPMCs mediated by SGK1. CONCLUSION Proinflammatory macrophages may play an essential role in the onset and development of NaCl-promoted inflammation in DSS-induced colitis. The underlining mechanism involves up-regulation of the p38/MAPK axis. 展开更多
关键词 inflammatory BOWEL disease MACROPHAGE NaCl CD4^+IFN-γ^+IL-17^+T cell p38/MAPK
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一种碳纤维生产管理信息化系统 被引量:1
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作者 党晓波 刘朝娥 +2 位作者 南晔 曹志强 申培君 《电子测试》 2022年第5期91-93,共3页
碳纤维有工业界“黑色黄金”的高端材料之称,随着国内科研院所的不断技术攻关,工艺技术水平得到了较大提高,碳纤维工程生产线不断建立。而碳纤维生产现场只有很有限的IT系统,并且这些系统通常以机械控制与自动化为导向,现场车间级的生... 碳纤维有工业界“黑色黄金”的高端材料之称,随着国内科研院所的不断技术攻关,工艺技术水平得到了较大提高,碳纤维工程生产线不断建立。而碳纤维生产现场只有很有限的IT系统,并且这些系统通常以机械控制与自动化为导向,现场车间级的生产及质量数据大量来自于人工录入,使得数据的实时性、准确性无法保证。本文介绍一种应用于碳纤维生产线的生产管理信息化系统。 展开更多
关键词 MES服务器 ERP系统 PDA扫码终端 应用计算机网络工程
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Texture Feature Extraction Method for Ground Nephogram Based on Contourlet and the Power Spectrum Analysis Algorithm
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作者 Xiaoying Chen Shijun Zhao +3 位作者 Xiaolei Wang Xuejin Sun Jing Feng nan ye 《Computers, Materials & Continua》 SCIE EI 2019年第8期861-875,共15页
It is important to extract texture feature from the ground-base cloud image for cloud type automatic detection.In this paper,a new method is presented to capture the contour edge,texture and geometric structure of clo... It is important to extract texture feature from the ground-base cloud image for cloud type automatic detection.In this paper,a new method is presented to capture the contour edge,texture and geometric structure of cloud images by using Contourlet and the power spectrum analysis algorithm.More abundant texture information is extracted.Cloud images can be obtained a multiscale and multidirection decomposition.The coefficient matrix from Contourlet transform of ground nephogram is calculated.The energy,mean and variance characteristics calculated from coefficient matrix are composed of the feature information.The frequency information of the data series from the feature vector values is obtained by the power spectrum analysis.Then Support Vector Machines(SVM)classifier is used to classify according to the frequency information of the trend graph of data series.It is shown that altocumulus and stratus with different texture frequencies can be effectively recognized and further subdivided the types of clouds. 展开更多
关键词 Ground nephogram super-wavelet CONTOURLET the power spectrum
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Corrosion Behaviors of Sputtered NiTiCu Shape Memory Films
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作者 nan ye Xueping Ren 《Journal of Materials Science and Chemical Engineering》 2020年第2期7-15,共9页
For NiTiCu SMA, the Ni atoms are substituted by Cu atoms, which not only greatly reduce the alloy cost, but also have excellent shape memory effect. Four kinds of shape memory alloy films (Ni49.6Ti50.4, Ni48.2Ti50.4Cu... For NiTiCu SMA, the Ni atoms are substituted by Cu atoms, which not only greatly reduce the alloy cost, but also have excellent shape memory effect. Four kinds of shape memory alloy films (Ni49.6Ti50.4, Ni48.2Ti50.4Cu1.4, Ni45.6Ti50.4Cu4, Ni42.7Ti50.4Cu6.9) were prepared using magnetron sputtering. Corrosion behaviors of the four films in phosphate buffered saline (PBS) solutions at 37&#176;C were examined using electrochemical impedance spectroscopy (EIS) method. It was found that the corrosion resistance of the NiTi film is superior to the three NiTiCu films. The EIS data were fitted using a parallel resistance-capacitance (as a constant phase element) circuit associated with the surface oxide film. The thickness of the surface oxide layer of the three NiTiCu films increases with applied potential till 0.8 V, while that of the NiTi film can reach to 1.2 V. 展开更多
关键词 Corrosion NiTiCu SHAPE MEMORY Alloy ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY NiTiCu FILMS
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High strength and ductility Mg-8Gd-3Y-0.5Zr alloy with bimodal structure and nano-precipitates 被引量:9
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作者 Xiaoxiao Wei Li Jin +4 位作者 Fenghua Wang Jing Li nan ye Zhenyan Zhang Jie Dong 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2020年第9期19-23,共5页
To resolve the strength-ductility trade-off problem for high-strength Mg alloys,we prepared a high performance Mg-8Gd-3Y-0.5 Zr(wt%)alloy with yield strength of 371 MPa,ultimate tensile strength of 419MPa and elongati... To resolve the strength-ductility trade-off problem for high-strength Mg alloys,we prepared a high performance Mg-8Gd-3Y-0.5 Zr(wt%)alloy with yield strength of 371 MPa,ultimate tensile strength of 419MPa and elongation of 15.8%.The processing route involves extrusion,pre-deformation and aging,which leads to a bimodal structure and nano-precipitates.Back-stress originated from the deformationincompatibility in the bimodal-structure alloy can improve ductility.In addition,dislocation density in coarse grains increased during the pre-deformation strain of 2%,and the dislocations in coarse grains can promote the formation of chain-like nano-precipitates during aging treatment.The chain-like nanoprecipitates can act as barriers for dislocations slip and the existing mobile dislocations enable good ductility. 展开更多
关键词 Magnesium alloy Strength-ductility trade-off Bimodal structure Back-stress Chain-like intragranular nano-precipitates
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微生物相互作用中的空间自组织
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作者 叶楠 侯贝贝 +2 位作者 王超 王瑞武 宋建潇 《生物多样性》 CAS CSCD 北大核心 2022年第5期150-160,共11页
微生物在全球生态系统中占据着重要地位,其中一个重要的研究领域是微生物与环境(包括无机环境与生物环境)之间的相互作用。在生态相互作用过程中,微生物常常通过自组织形成特定的空间模式。微生物的空间模式在种群稳定性、群落动态变化... 微生物在全球生态系统中占据着重要地位,其中一个重要的研究领域是微生物与环境(包括无机环境与生物环境)之间的相互作用。在生态相互作用过程中,微生物常常通过自组织形成特定的空间模式。微生物的空间模式在种群稳定性、群落动态变化以及维持合作行为方面具有重要作用。本文中,我们梳理了当下对微生物空间自组织及其所形成的空间模式的研究内容,首先介绍什么是空间自组织,再根据生态相互作用类型对自组织的空间模式进行描述,其中重点讨论合作与竞争中的空间模式,接着关注微生物空间自组织的过程,最后我们指出空间自组织对整个群体的结构和功能稳定具有重要意义。研究微生物种群间相互作用中的空间模式,有助于探索维持合作行为的新机制,进而为微生物共生系统的构建提供新的理解。 展开更多
关键词 微生物 空间模式 空间自组织 微生物相互作用 合作竞争
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Abnormality in coronary slow flow phenomenon detected by nailfold microcirculation microanalysis 被引量:2
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作者 He-Xi Zhang nan ye +3 位作者 Fei Peng Li-Jian Pan Yi-Jun Shi Hui Gong 《Chinese Medical Journal》 SCIE CAS CSCD 2021年第11期1370-1372,共3页
To the Editor:The coronary slow flow phenomenon(CSFP)was first reported by Tambe et al in 1972.[1]Specifically,patients suffering from chest pain but without significant coronary artery lesion,displayed slow coronary ... To the Editor:The coronary slow flow phenomenon(CSFP)was first reported by Tambe et al in 1972.[1]Specifically,patients suffering from chest pain but without significant coronary artery lesion,displayed slow coronary blood flow during coronary angiography examination,which could lead to myocardial ischemia,acute myocardial infarction,and acute coronary syndrome.The development of CSFP has been reported to be around 7%in patients with suspected coronary heart disease.[2]The common clinical symptoms during CSFP include slow opacification of distal parts of normal epicardial coronary arteries in the absence of ventricular dysfunction,connective tissue disorder,valvular heart diseases,and coronary spasm or ectasia.Nowadays,the identification of the CSFP is achieved through coronary angiography by thrombolysis in myocardial infarction(TIMI)flow grade.The corrected TIMI frame count(CTFC)is a very common,simple,and repeatable method used for the quantification of the coronary flow.[3] 展开更多
关键词 CORONARY ACUTE INFARCTION
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Discovery of dinoflagellates from the Dengshan Group in NE Jiangxi Province and its significance
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作者 Zhengguo Zhou Changshuo Yue +4 位作者 Kezhao He Chonghe Zhao Zetong Nie Daoqian Tai nan ye 《Chinese Science Bulletin》 SCIE EI CAS 1999年第18期1688-1690,共3页
From the stratotype section of the Bazhukeng Formation, Dengshan Group (formerly assigned to the late Proterozoic), situated at Dengshan Village, Zhujia, Yiyang County, Jiangxi Province, three dinoflagellate-bearing h... From the stratotype section of the Bazhukeng Formation, Dengshan Group (formerly assigned to the late Proterozoic), situated at Dengshan Village, Zhujia, Yiyang County, Jiangxi Province, three dinoflagellate-bearing horizons have been found, in which the lower two contain ?Conochitina sp. and Cyathochitina sp., while the upper yields ?Conochitina sp. 展开更多
关键词 NE JIANGXI Dengshan Group early PALEOZOIC dinoflagellata.
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Closed Strong Spacelike Curves, Fenchel Theorem and Plateau Problem in the 3-Dimensional Minkowski Space
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作者 nan ye Xiang MA 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2019年第2期217-226,共10页
The authors generalize the Fenchel theorem for strong spacelike closed curves of index 1 in the 3-dimensional Minkowski space, showing that the total curvature must be less than or equal to 2π. Here the strong spacel... The authors generalize the Fenchel theorem for strong spacelike closed curves of index 1 in the 3-dimensional Minkowski space, showing that the total curvature must be less than or equal to 2π. Here the strong spacelike condition means that the tangent vector and the curvature vector span a spacelike 2-plane at each point of the curve γ under consideration. The assumption of index 1 is equivalent to saying that γ winds around some timelike axis with winding number 1. This reversed Fenchel-type inequality is proved by constructing a ruled spacelike surface with the given curve as boundary and applying the Gauss-Bonnet formula. As a by-product, this shows the existence of a maximal surface with γ as the boundary. 展开更多
关键词 Fenchel THEOREM Spacelike CURVES Total CURVATURE MAXIMAL surface
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