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convergent plate boundary environments for formation of≥3800 Ma mafic-ultramafic assemblages(Isua area,Greenland):Implications for early global geodynamics

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Geoscience Frontiers 2024年第3期15卷 119-136页

作者： Allen P.Nutman clark R.L.Friend Vickie c.Bennett School of Earth Atmospheric and Life SciencesUniversity of WollongongWollongongNSW 2522Australia Glendale TiddingtonOxon OX92LQUK Research School of Earth Sciences Australian National UniversityCanberraACT 2601Australia

In the gneiss terrane on the south side of the Eoarchean Isua supracrustal belt,ultramafic rocks with relict abyssal peridotite mineralogy(Bennett et al.,2002;Friend et al.,2002;Nutman et al.,2007;Rollinson,2007;van de Löcht et al.,2020),layered gabbros with cumulate ultramafic rocks,basalts and associated siliceous sedimentary rocks were tectonically-imbricated,prior to and during intrusion of ca.3800 Ma *** with3800 Ma basalts in the Outer Arc Group of the nearby Isua supracrustal belt,the composition of all these mafic rocks(e.g.,Th-Hf-Nb systematics,high Th/Yb,Ba/Nb,Ba/Yb ratios and negative Nb and Ti anomalies)shows affinity with modern suprasubduction rocks whose genesis involved fluid fluxing of the upper ***,the majority of these samples have Ba/Nb and Ba/Yb values less than in modern island arc magmas,but similar to many backarc basin magmas(e.g.,Pearce and stern,2006).It is unknown whether these ca.3800 Ma mafic rocks are,(i)arc rocks where the Ba/Nb and Ba/Yb signatures reflect lower surficial Ba in Eoarchean oceanic settings,or(ii)in direct comparison with Phanerozoic suites,these signatures reflect a back-arc setting with interplay between fluid fluxing and decompressional *** tectonic intercalation of upper mantle with lower and upper crustal rocks,combined with the fluid-fluxing influences seen in chemistry of all the mafic rocks is best accommodated in a compressional Eoarchean convergent plate boundary setting within a mobile-lid *** stagnant lid scenarios of crust formation,if operative,must have co-existed or alternated with mobile-lid regimes by 3800 Ma.

关键词： Eoarchean Fluid-fluxing Plate tectonics Suprasubduction crustal evolution

从微孔洞起始的热冲击裂纹的数值研究——Ⅰ:热应力分析

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复合材料学报 2002年第5期19卷 75-78页

作者：贺鹏飞李京剑 Yuan c.stern R clegg W J 上海交通大学金属基复合材料国家重点实验室上海200030 深圳市宝发实业有限公司 DepartmentofMaterialsScienceandMetallurgy

陶瓷材料在热冲击荷载作用下的典型破坏模式是裂纹的起始和扩展。当高温的材料或构件突然处于低温环境时 ,裂纹将由材料或构件的表面开始产生和发展。因此 ,材料表面及其表面附近的材料微结构对裂纹的起始有着非常重要的影响。实验表明 ... 详细信息

陶瓷材料在热冲击荷载作用下的典型破坏模式是裂纹的起始和扩展。当高温的材料或构件突然处于低温环境时 ,裂纹将由材料或构件的表面开始产生和发展。因此 ,材料表面及其表面附近的材料微结构对裂纹的起始有着非常重要的影响。实验表明 :某些具有微孔洞结构的陶瓷材料比相应的密实材料的抗热冲击性能有所提高 ,但相关的机制目前还没有得到定量的解释。本文作者利用商业有限元软件 ABAQUS,分析了受热冲击表面上的开口微孔洞、处于表面附近的闭口微孔洞周围的热应力场 ,以及微孔洞的大小、微孔洞与表面的距离对热应力场的影响 ,其目的是为进一步分析裂纹的起始和扩展做准备。数值结果表明 :一般情况下 ,闭口微孔洞引起的应力集中比开口微孔洞引起的应力集中更为严重 ,特别当闭口微孔洞与表面之间的距离很小时 ,和没有微孔洞情况相比 ,闭口微孔洞引起的最大的应力集中系数超过

关键词：热冲击裂纹陶瓷微孔洞热应力数值分析损伤

从微孔洞起始的热冲击裂纹的数值研究——Ⅱ:能量释放率分析

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复合材料学报 2002年第5期19卷 79-83页

利用商业的有限元软件 ABAQU S,分析了具有微孔洞结构氧化铝陶瓷材料在受到热冲击作用下 ,从处于材料表面上的开口微孔洞以及临近材料表面的闭口微孔洞的底部起始的裂纹扩展。结果表明 :对于从开口微孔洞和闭口微孔洞底部起始的裂纹 ,... 详细信息

利用商业的有限元软件 ABAQU S,分析了具有微孔洞结构氧化铝陶瓷材料在受到热冲击作用下 ,从处于材料表面上的开口微孔洞以及临近材料表面的闭口微孔洞的底部起始的裂纹扩展。结果表明 :对于从开口微孔洞和闭口微孔洞底部起始的裂纹 ,其能量释放率随冷却时间的变化规律类似 ,即随冷却时间 t由零开始增加 ,能量释放率也由零开始快速增大 ,在冷却时间大约为 t=0 .1s时 ,达到其最大值 ,随后开始降低。另外对于从开口微孔洞底部起始的裂纹 ,结果发现裂纹的能量释放率随裂纹长度的增加、微孔洞半径的增加而增加 ,而对于从闭口微孔洞底部起始的裂纹 ,其能量释放率随裂纹长度的增加、微孔洞半径的增加、以及微孔洞与材料受热冲击面距离的增加而增加。以开口微孔洞底部起始的裂纹为例 ,研究了裂纹与临近微孔洞之间的作用 ,发现临近微孔洞的存在可以明显减小裂纹的能量释放率。

关键词：数值研究裂纹热冲击能量释放率微孔洞陶瓷氮化铝

南美洲南端巴塔哥尼亚高原熔岩中的上新世—第四纪碱性玄武岩的微量元素和Sr、Nd、Pb和O的同位素组成

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地质地球化学 1991年第2期19卷 39-48页

作者： c.R.stern 胡瑞忠

南美洲南端巴塔哥尼亚高原的上新世—第四纪碱性玄武岩可分为两类:“克拉通”玄武岩和“过渡”玄武岩。“克拉通”玄武岩分布于新生代高原火山活动区和大陆沉积岩分布区,其同位素组成变化大:^(87)Sr/^(86)Sr比值为0.70316—0.70512;ε_(... 详细信息

南美洲南端巴塔哥尼亚高原的上新世—第四纪碱性玄武岩可分为两类:“克拉通”玄武岩和“过渡”玄武岩。“克拉通”玄武岩分布于新生代高原火山活动区和大陆沉积岩分布区,其同位素组成变化大:^(87)Sr/^(86)Sr比值为0.70316—0.70512;ε_(Nd)为0—+5.5;^(206)Pb/^(204)Pb\^(207)Pb/^(204)Pb和^(208)Pb/^(204)Pb比值分别为18.26—19.38、15.53—15.68和38.30—39.23。“克拉通”玄武岩的这些同位素值以及Ba/La、Ba/Nb、La/Nb、K/Rb和cs/Rb比值都落在海岛玄武岩的范围内。“过渡”玄武岩分布于上新世—第四纪高原熔岩露头带的西缘,这一区域原先为新生代早期安第斯造山弧火山活动区。与“克拉通”玄武岩相反,“过渡”玄武岩的同位素组成的变化范围要小得多:^(87)Sr/^(86)Sr比值为0.7039±0.0004;ε_(Nd)为+4.0±1.1;^(206)Pb/^(204)Pb、^(207)Pb/^(204)Pb和^(208)Pb/^(204)Pb比值分别为18.60±0.08、15.60±0.01和38.50±0.10。这些同位素值类似于安第斯造山弧玄武岩;与“克拉通”玄武岩相比,当^(143)Nd/^(144)Nd和^(208)Pb/^(204)Pb比值一定时,^(87)Sr/^(86)Sr比值和^(207)Pb/^(204)Pb比值都较高。虽然“过渡”玄武岩的Ba/La、Ba/Nb、La/Nb和cs/Rb比值不如安第斯造山弧玄武岩那样高,但它们仍高于“克拉通”?

关键词：玄武岩微量元素 Sr Nd Pb 同位素

Impact of ribavirin dose on retreatment of chronic hepatitis c patients

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World Journal of Gastroenterology 2012年第23期18卷 2966-2972页

作者： christiane stern Michelle Martinot-Peignoux Marie Pierre Ripault Nathalie Boyer corinne castelnau Dominique Valla Patrick Marcellin Service d'Hépatologie and INSERM U773-cRB3 H pital Beaujon University Paris-Diderot

AIM: To study the efficacy and factors associated with a sustained virological response (SVR) in chronic hepatitis c (cHc) relapsing patients. METHODS: Out of 1228 cHc patients treated with pegylated interferon (PEG-IFN) and ribavirin (RBV), 165 (13%) had a relapse. Among these, 62 patients were retreated with PEG-IFN-2a or-2b and RBV. clinical, biological, virological and histological data were collected. Initial doses and treatment modifications were recorded. The efficacy of retreatment and predictive factors for SVR were analyzed. RESULTS: An SVR was achieved in 42% of patients. SVR was higher in young (course was associated with higher SVR rates (53% vs 28%, P = 0.04). Also, a better SVR rate was observed with RBV dose/body weight > 15.2 mg/kg per day (70% vs 35%, P = 0.04). In logistic regression, predictors of a response were age (P = 0.018), genotype (P = 0.048) and initial RBV dose/body weight (P = 0.022). None of the patients without a complete early virological response achieved an SVR (negative predictive value = 100%). cONcLUSION: Retreatment with PEG-IFN/RBV is effective in genotype 2 or 3 relapsers, especially in young patients. A high dose of RBV seems to be important for the retreatment response.

关键词： chronic hepatitis c Relapse Retreatment Ribavirin Pegylated interferon

The Use and Reuse of Julius caesar＇s Religious Résumé on Imperatorial coinage

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Journal of Literature and Art Studies 2014年第1期4卷 62-74页

作者： Gaius stern University of california Berkeley USA

Soon after Roman mint masters began issuing the silver denarius （traditional date 187 B.c.）, they discovered that they could employ coinage as newspapers and PR by individualizing the imagery on each side of the coin with references to their ancestry, current events, and/or their religious offices to increase their name recognition in order to win votes. It should come as no surprise that the Divine Julius ordered his mint masters to issue coinage that advertised all of the above features to circulate his good reputation in what our modern political scientists would call propaganda. After Julius＇ enemies began to attack his reputation, some of his partisans boasted of their closeness to him on coinage by recycling specific coin images. What is surprising is how these partisans adopted the exact imagery Julius had used to advertise his own religious résumé on their coinage, even though these religious images could not and did not apply to them specifically. Apparently, Julius＇ religious résumé no longer demonstrated a religious portfolio, but had transformed into a badge of partisanship, however thinly it applied, so that the religious symbols themselves retained only the function of an association with Julius without their original and intrinsic meaning.

关键词： Roman history Roman religion Roman coinage Julius caesar Augustus lituus simpulum numismatics Second Triumvirate

Minor Pressure Differences within the Fontan-Anastomosis in Patients with Total cavopulmonary connection by 4D-Flow Magnetic Resonance Imaging

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congenital Heart Disease 2023年第4期18卷 461-474页

作者： Nerejda Shehu christian Meierhofer Anja Hennemuth Markus Hüllebrand Pavlo Yevtushenko Peter Ewert Stefan Martinoff Heiko stern Department of congenital Heart Disease and Pediatric cardiology German Heart Center MunichTechnical University of MunichMunichGermany Fraunhofer Institute for Digital Medicine—MEVIS BerlinGermany Institute for cardiovascular computer-Assisted Medicine CharitéUniversitätsmedizinBerlinGermany Department of Radiology German Heart Center MunichTechnical University of MunichMunichGermany

Background: Pressure measurement in total cavopulmonary connection (TcPc) patients is a domain of cardiaccatheterization. 4D velocity encoded cardiovascular magnetic resonance (4D–flow MRI) offers an alternative forassessment of even minor pressure differences. The scope of this study was to measure even minor pressure differencesin the anastomosis of TcPc patients, who are clinically uncompromised. Methods: Twenty-four patients(median 15 years [8;34]) with TcPc were studied prospectively by 4D-flow MRI. Pressure differences betweensuperior vena cava (SVc) and extracardiac conduit (c) to both right pulmonary artery (RPA) and left pulmonaryartery (LPA) were assessed. Small fluid obstructions as vortices within the anastomosis were detected by flowpathlines from 4D-flow MRI. In two patients pressure differences were calculated also by computational flowdynamics (cFD) as a plausibility check for the order of magnitude. Results: Median values of pressure differencesin the anastomosis between SVc and RPA were 0.63 (0.21–2.1) mmHg, between c and RPA 0.67 (0.3–2.2)mmHg, between SVc and LPA 0.8 (0.3–2.4) mmHg and between c and LPA 0.7 (0.2–1.9) mmHg. Patients withpotential flow obstruction (stents, occluder, vortices) had significantly higher gradients at the anastomosis (p ctions, although the absolute values were small. cFD- and measurement-based pressure difference showed good agreement. conclusion: 4D-flow MRI is able to detect minor pressuredifferences within the Fontan circuit even in patients with apparently satisfactory TcPc. Slightly higherpressure differences are due to the presence of small flow obstruction.

关键词： 4D-flow MRI pressure differences TcPc Fontan