期刊文献+
共找到2,487篇文章
< 1 2 125 >
每页显示 20 50 100
Commentary on "Association of daily sitting time and leisure-time physical activity with body fat among U.S.adults"
1
作者 Barbara E.Ainsworth 《Journal of Sport and Health Science》 SCIE CAS CSCD 2024年第2期127-129,共3页
In their study,association of daily sitting time and leisure-time physical activity (LTPA) with body fat among U.S.Adults,Liao et al.^(1) analyzed data from the 2011-2018 National Health and Examination Survey to exam... In their study,association of daily sitting time and leisure-time physical activity (LTPA) with body fat among U.S.Adults,Liao et al.^(1) analyzed data from the 2011-2018 National Health and Examination Survey to examine associations between h/day sitting,meeting (or not meeting) the U.S.Physical Activity Guidelines of≥150 min/week of moderate-and vigorous-intensity LTPA,and combinations of sitting time and LTPA on totaland trunk percent body fat (BF%). 展开更多
关键词 u.s. aDuLT aMONG
下载PDF
新质生产力视域下的U-G-S模式智慧校园建设
2
作者 林德力 《福建电脑》 2025年第1期41-49,共9页
智慧教育是教育体系建设中非常重要的一环,培养合格的新质生产力的劳动者是智慧校园建设的目标之一。本文研究和分析新质生产力、U-G-S模式与智慧校园建设之间的关联性,并以实例展示基于新质生产力的U-G-S模式智慧校园总体架构模型。对... 智慧教育是教育体系建设中非常重要的一环,培养合格的新质生产力的劳动者是智慧校园建设的目标之一。本文研究和分析新质生产力、U-G-S模式与智慧校园建设之间的关联性,并以实例展示基于新质生产力的U-G-S模式智慧校园总体架构模型。对该模型的实施效果调查分析的结果表明,U-G-S模式下的智慧校园运行获得了较为满意的效果。 展开更多
关键词 u-G-s模式 智慧校园 新质生产力
下载PDF
The Reception Commemorating the 45th Anniversary of China-U.S.Diplomatic Ties Held in Beijing
3
《International Understanding》 2024年第1期40-40,共1页
On January 5,the Chinese People's Association for Friendship with Foreign Countries and the Chinese People's Institute of Foreign Affairs jointly hosted a reception commemorating the 45th anniversary of the es... On January 5,the Chinese People's Association for Friendship with Foreign Countries and the Chinese People's Institute of Foreign Affairs jointly hosted a reception commemorating the 45th anniversary of the establishment of diplomatic relationship between China and the United States in Beijing.Member of the Political Bureau of the CPC Central Committee and Foreign Minister Wang Yi attended the commemoration and delivered aspeech.David Meale,ChargédAffaires at the U.S.Embassy in China,addressed the reception.He extended on behalf of the U.S.side congratulations on the anniversary,expressing the readiness of the U.S.to implement the consensus reached by the two heads of state and promote the steady development of U.S.-China relations.More than 350 people from all walks of life of both countries attended the reception. 展开更多
关键词 jointly u.s. behalf
下载PDF
FREE SPEECH OR SINOPHOBIA? THE U.S. SENATE MUST DECIDE
4
作者 Anthony Moretti 《China Report ASEAN》 2024年第4期63-64,共2页
The 100 men and women who make up the U.S.Senate will soon have an important choice.They will either affirm that the First Amendment matters or they will surrender to fear.The senators must decide whether to go along ... The 100 men and women who make up the U.S.Senate will soon have an important choice.They will either affirm that the First Amendment matters or they will surrender to fear.The senators must decide whether to go along with their colleagues in the House of Representatives and require the popular social media app TikTok to be sold to an American company.If they do endorse the House vote,then ByteDance must divest itself of TikTok or see the app will be banned on U.S.-based social media platforms. 展开更多
关键词 u.s. RENDER sOON
下载PDF
Cross-Cultural Adjustment and Coping:U.S.Students in Taiwan Residents Higher Education
5
作者 Wen-Ling Lou 《Sino-US English Teaching》 2024年第1期26-42,共17页
The aim of this study was to investigate the adjustment problems of students from the United States enrolled in universities in the East,specifically in Taiwan,their problems related to cultural adaptation,and the pro... The aim of this study was to investigate the adjustment problems of students from the United States enrolled in universities in the East,specifically in Taiwan,their problems related to cultural adaptation,and the process of adjustment to student life in Taiwan.Under investigation were cultural adjustment and coping skills as these students transitioned from West to East.Qualitative data were collected from interviews with participants and faculty members as well as participant observations.Results indicated that U.S.students found their own ways to acclimate to their new academic setting as well as to social relations,cross-cultural issues,and the linguistic environment in Taiwan to achieve effective adaptation.They made changes in themselves to cope with all situations they encountered.This study provides suggestions for international students abroad in Taiwan,for the Taiwan Residents government,and for universities or colleges in terms of what they should offer to current and future international students. 展开更多
关键词 adjustment cultural adjustment cross-cultural adaptation COPING u.s.students
下载PDF
The Influence of Christian Nationalism on U.S.Foreign Policy
6
作者 PU Jingxin 《International Relations and Diplomacy》 2024年第5期191-195,共5页
This paper explores the influence of Christian nationalism on U.S.foreign policy,examining its historical roots,ideological foundations,and contemporary implications.Christian nationalism,an ideology that links Christ... This paper explores the influence of Christian nationalism on U.S.foreign policy,examining its historical roots,ideological foundations,and contemporary implications.Christian nationalism,an ideology that links Christianity with national identity,has shaped U.S.foreign policy in areas such as religious freedom,Middle East diplomacy,and national security.Through its emphasis on the moral duty to defend Christianity and its promotion of conservative social values,Christian nationalism has affected U.S.relations with countries around the world,particularly in the Middle East and with religious minorities.The paper discusses the complexities and controversies surrounding Christian nationalism,its impact on the U.S.’s global image,and the challenges it poses to religious pluralism.The future of Christian nationalism’s influence on U.S.foreign policy is uncertain,as societal shifts and evolving global dynamics may prompt a reevaluation of its role in shaping America’s international actions.Overall,the paper provides a nuanced analysis of how Christian nationalism has intertwined with U.S.foreign policy and how its influence might evolve in the future. 展开更多
关键词 Christian nationalism u.s.foreign policy religious freedom Middle East diplomacy american exceptionalism
下载PDF
Digital Disparities:How Artificial Intelligence Can Facilitate Anti-Black Racism in the U.S.Healthcare Sector
7
作者 Anthony Victor Onwuegbuzia 《International Relations and Diplomacy》 2024年第1期40-50,共11页
This paper delves into the intricate interplay between artificial intelligence(AI)systems and the perpetuation of Anti-Black racism within the United States medical industry.Despite the promising potential of AI to en... This paper delves into the intricate interplay between artificial intelligence(AI)systems and the perpetuation of Anti-Black racism within the United States medical industry.Despite the promising potential of AI to enhance healthcare outcomes and reduce disparities,there is a growing concern that these technologies may inadvertently/advertently exacerbate existing racial inequalities.Focusing specifically on the experiences of Black patients,this research investigates how the following AI components:medical algorithms,machine learning,and natural learning processes are contributing to the unequal distribution of medical resources,diagnosis,and health care treatment of those classified as Black.Furthermore,this review employs a multidisciplinary approach,combining insights from computer science,medical ethics,and social justice theory to analyze the mechanisms through which AI systems may encode and reinforce racial biases.By dissecting the three primary components of AI,this paper aims to present a clear understanding of how these technologies work,how they intersect,and how they may inherently perpetuate harmful stereotypes resulting in negligent outcomes for Black patients.Furthermore,this paper explores the ethical implications of deploying AI in healthcare settings and calls for increased transparency,accountability,and diversity in the development and implementation of these technologies.Finally,it is important that I prefer the following paper with a clear and concise definition of what I refer to as Anti-Black racism throughout the text.Therefore,I assert the following:Anti-Black racism refers to prejudice,discrimination,or antagonism directed against individuals or communities of African descent based on their race.It involves the belief in the inherent superiority of one race over another and the systemic and institutional practices that perpetuate inequality and disadvantage for Black people.Furthermore,I proclaim that this form of racism can be manifested in various ways,such as unequal access to opportunities,resources,education,employment,and fair treatment within social,economic,and political systems.It is also pertinent to acknowledge that Anti-Black racism is deeply rooted in historical and societal structures throughout the U.S.borders and beyond,leading to systemic disadvantages and disparities that impact the well-being and life chances of Black individuals and communities.Addressing Anti-Black racism involves recognizing and challenging both individual attitudes and systemic structures that contribute to discrimination and inequality.Efforts to combat Anti-Black racism include promoting awareness,education,advocacy for policy changes,and fostering a culture of inclusivity and equality. 展开更多
关键词 Bias in algorithms Racial disparities in u.s.healthcare Discriminatory healthcare practices Black patient outcomes automated decision-making and racism Machine Learning Natural language processing
下载PDF
LPS'S CRITERION FOR INCOMPRESSIBLE NEMATIC LIQUID CRYSTAL FLOWS 被引量:3
8
作者 陈卿 谭忠 吴国春 《Acta Mathematica Scientia》 SCIE CSCD 2014年第4期1072-1080,共9页
In this paper we derive LPS's criterion for the breakdown of classical solutions to the incompressible nematic liquid crystal flow, a simplified version of Ericksen-Leslie system modeling the hydrodynamic evolution o... In this paper we derive LPS's criterion for the breakdown of classical solutions to the incompressible nematic liquid crystal flow, a simplified version of Ericksen-Leslie system modeling the hydrodynamic evolution of nematic liquid crystals in R^3. We show that if 0 〈 T 〈 +∞ is the maximal time interval for the unique smooth solution u ∈ C^∞([0, T),R^3),then |u|+|△d|∈L^q([0,T],L^p(R^3)),where p and q satisfy the Ladyzhenskaya-Prodi-Serrin's condition:3/p+2/q=1 and p∈(3,+∞]. 展开更多
关键词 incompressible nematic liquid crystal flow Ladyzhenskaya-Prodi-serrin's criterion
下载PDF
Numerical analyses of pillar behavior with variation in yield criterion,dilatancy, rock heterogeneity and length to width ratio 被引量:2
9
作者 Sankhaneel Sinha Gabriel Walton 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2019年第1期46-60,共15页
With recent advances in numerical modeling, design of underground structures increasingly relies on numerical modeling-based analysis approaches. While modeling tools like the discrete element method(DEM) and the comb... With recent advances in numerical modeling, design of underground structures increasingly relies on numerical modeling-based analysis approaches. While modeling tools like the discrete element method(DEM) and the combined finite-discrete element method(FDEM) are useful for investigating small-scale damage processes, continuum models remain the primary practical tool for most field-scale problems.The results obtained from such models are significantly dependent on the selection of an appropriate yield criterion and dilation angle. Towards improving its capabilities in handling mining-related problems, the authors have previously developed a new yield criterion(called progressive S-shaped criterion). The focus of the current study is to demonstrate its use in modeling rock pillars through a comparative analysis against four other yield criteria. In addition to the progressive S-shaped criterion,only one out of the four other criteria predicted a trend in strength consistent with an empirical pillar strength database compiled from the literature. Given the closely-knit relationship between yield criteria and dilation angle in controlling the overall damage process, a separate comparison was conducted using a mobilized dilation model, a zero degree dilation angle and a constant non-zero dilation angle. This study also investigates the impact of meso-scale heterogeneity in mechanical properties on the overall model response by assigning probability distributions to the input parameters. The comparisons revealed that an isotropic model using a combination of progressive S-shaped criterion and mobilized dilation angle model is sufficient in capturing the behaviors of rock pillars. Subsequently, the pillar model was used to assess the effect of L/W(length/width) ratio on the peak strength. 展开更多
关键词 Rock PILLaRs PROGREssIVE s-shaped criterion Numerical modeling
下载PDF
Strength criterion of porous media: Application of homogenization techniques
10
作者 L. Dormieux E. Lemarchand +1 位作者 D. Kondo S. Brach 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2017年第1期62-73,共12页
The present paper aims at giving some general ideas concerning the micromechanical approach of the strength of a porous material. It is shown that its determination theoretically amounts to solving a nonlinear boundar... The present paper aims at giving some general ideas concerning the micromechanical approach of the strength of a porous material. It is shown that its determination theoretically amounts to solving a nonlinear boundary value problem defined on a representative elementary volume(REV). The principle of nonlinear homogenization is illustrated based on the case of a solid phase having a Green’s strength criterion. An original refinement of the so-called secant method(based on two reference strains) is also provided. The paper also describes the main feature of the Gurson’s model which implements the principle of limit analysis on a conceptual model of hollow sphere. The last part of the paper gives some ideas concerning poromechanical couplings. 展开更多
关键词 strength criterion Porous media Homogenization techniques Nonlinear behavior Limit analysis Gurson’s model
下载PDF
Absolutely Stable of Takagi-Sugeno Fuzzy Control System by Using Popov’s Criterion
11
作者 Azhdar Soleymanpour Bakefayat Aghileh Heydari 《Applied Mathematics》 2012年第10期1124-1127,共4页
In this paper, we presented a sufficient condition on the frequency domain for the absolutely stable analysis of the Takagi-Sugeno (T-S)fuzzy control system, based on the Popov’s criterion. we use some numerical exam... In this paper, we presented a sufficient condition on the frequency domain for the absolutely stable analysis of the Takagi-Sugeno (T-S)fuzzy control system, based on the Popov’s criterion. we use some numerical examples to illustrate the efficiency of frequency domain-based condition. 展开更多
关键词 FuZZY CONTROL FuZZY sYsTEMs Popov’s criterion
下载PDF
Relations between cubic equation, stress tensor decomposition, and von Mises yield criterion
12
作者 Haoyuan GUO Liyuan ZHANG +1 位作者 Yajun YIN Yongxin GAO 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2015年第10期1359-1370,共12页
Inspired by Cardano's method for solving cubic scalar equations, the addi- tive decomposition of spherical/deviatoric tensor (DSDT) is revisited from a new view- point. This decomposition simplifies the cubic tenso... Inspired by Cardano's method for solving cubic scalar equations, the addi- tive decomposition of spherical/deviatoric tensor (DSDT) is revisited from a new view- point. This decomposition simplifies the cubic tensor equation, decouples the spher- ical/deviatoric strain energy density, and lays the foundation for the von Mises yield criterion. Besides, it is verified that under the precondition of energy decoupling and the simplest form, the DSDT is the only possible form of the additive decomposition with physical meanings. 展开更多
关键词 Cardano's method Caylay-Hamilton theorem cubic tensor equation decomposition of spherical/deviatoric tensor (DsDT) von Mises yield criterion
下载PDF
Stability analysis of the simplest Takagi-Sugeno fuzzy control system using circle criterion
13
作者 Lu Hongqian Huang Xianlin +2 位作者 Gao X. Z. Ban Xiaojun Yin Hang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2007年第2期311-319,共9页
A frequency-domain-based sufficient condition is derived to guarantee the globally asymptotic stability of the simplest Takagi-Sugeno (T-S) fuzzy control system by using the circle criterion. The analysis is perform... A frequency-domain-based sufficient condition is derived to guarantee the globally asymptotic stability of the simplest Takagi-Sugeno (T-S) fuzzy control system by using the circle criterion. The analysis is performed in the frequency domain, and hence the condition is of great significance when the frequency-response method, which is widely used in the linear control theory and practice, is employed to synthesize the simplest T-S fuzzy controller. Besides, this sufficient condition is featured by a graphical interpretation, which makes the condition straightforward to be used. Comparisons are drawn between the performance of the simplest T-S fuzzy controller and that of the linear compensator. Two numerical examples are presented to demonstrate how this sufficient condition can be applied to both stable and unstable plants. 展开更多
关键词 T-s fuzzy controller stability analysis Circle criterion Frequency response method.
下载PDF
教育硕士产教融合“U-G-S&E”育人模式探析 被引量:1
14
作者 赵兴碧 章光洁 董红梅 《西南林业大学学报(社会科学)》 2024年第4期104-109,共6页
产教融合是教育与产业的深度合作,我国产教融合的政策经历了从职业教育到普通教育的发展。产教融合符合教育硕士人才培养的逻辑,“U-G-S&E”育人模式以高校为主导,政府提供政策引导和资金支持,中小学和企业协同参与教育硕士的培养... 产教融合是教育与产业的深度合作,我国产教融合的政策经历了从职业教育到普通教育的发展。产教融合符合教育硕士人才培养的逻辑,“U-G-S&E”育人模式以高校为主导,政府提供政策引导和资金支持,中小学和企业协同参与教育硕士的培养。通过实践探索发现,“U-G-S&E”模式可以更好地激发学生提升职业能力的动力,助力学生职业生涯规划和就业,提升以赛赋能的效果,帮助高校校内导师、中小学和企业的校外导师加深对教育链、人才链与产业链、创新链有机衔接的理解,助力孵化本地企业参与遴选国家产教融合型企业,推动本地企业更好的融入国家现代教育体系建设。 展开更多
关键词 教育硕士 产教融合 u-G-s&E 职业能力
下载PDF
利用Yabuki & Matsu′ura反演方法计算2011年日本东北地区太平洋海域M_w9.0级地震同震滑动分布 被引量:5
15
作者 王阅兵 金红林 +1 位作者 付广裕 孟国杰 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2012年第8期2551-2560,共10页
Yabuki&Matsu′ura反演方法是利用ABIC最佳模型参数选取方法和平滑的滑动分布作为约束条件,由形变观测数据计算发震断层滑动分布.本文基于日本列岛同震GPS观测数据和发震断层曲面构造模型,利用Yabuki&Matsu′ura反演方法计算201... Yabuki&Matsu′ura反演方法是利用ABIC最佳模型参数选取方法和平滑的滑动分布作为约束条件,由形变观测数据计算发震断层滑动分布.本文基于日本列岛同震GPS观测数据和发震断层曲面构造模型,利用Yabuki&Matsu′ura反演方法计算2011年日本东北地区太平洋海域Mw9.0级地震的发震断层同震滑动分布.反演结果表明,断层面上的最大滑动量为35m,较大滑动分布在浅于30km的震源中心上部,最大破裂集中在20km深度的地方.其地震矩约为3.63×1022 N.m,对应的矩震级为Mw9.0.模拟结果显示Yabuki&Matsu′ura反演方法更适用于倾角低于40°的断层模型反演.最后,本文基于上述方法获得的发震断层滑动模型,利用地球体位错理论正演计算该地震在中国及其邻区产生的远场形变,正演计算结果基本可以解释由中国GPS陆态网络观测到的同震形变. 展开更多
关键词 Yabuki & Matsuura反演方法 akaike′s Bayesian Information criterion(aBIC) 断层滑动分布模型 日本Mw9.0级地震
下载PDF
银莲花素A对S180、H22和U14细胞小鼠移植瘤的抑制作用 被引量:11
16
作者 王明奎 丁立生 吴凤锷 《癌症》 SCIE CAS CSCD 北大核心 2008年第9期910-913,共4页
背景与目的:有研究证明,从两头尖中分离得到的三萜皂甙银莲花素A在体外具有较好的抑瘤活性。本研究将观察银莲花素A在体内对小鼠移植瘤的抑制活性。方法:MTT法检测银莲花素A对人鼻咽癌KB细胞和人卵巢癌SKOV3细胞的抑制率。体内实验选取... 背景与目的:有研究证明,从两头尖中分离得到的三萜皂甙银莲花素A在体外具有较好的抑瘤活性。本研究将观察银莲花素A在体内对小鼠移植瘤的抑制活性。方法:MTT法检测银莲花素A对人鼻咽癌KB细胞和人卵巢癌SKOV3细胞的抑制率。体内实验选取小鼠肉瘤S180细胞、小鼠肝癌H22细胞和小鼠宫颈癌U14细胞,观察银莲花素A注射给药对S180、H22和U14细胞小鼠移植瘤的抑瘤率,以及灌胃给药对小鼠肉瘤S180移植瘤的抑瘤率。测定银莲花素A的急性毒性。结果:银莲花素A在体外对KB细胞和SKOV3细胞的IC50分别为4.64!g/mL和1.40!g/mL。4.5mg/kg银莲花素A腹腔注射对S180、H22和U14细胞小鼠移植瘤的抑瘤率分别为60.5%、36.2%和61.8%。200mg/kg灌胃给药时抑瘤率为64.7%。灌胃给药和腹腔注射银莲花素A的LD50分别为1.1g/kg和16.1mg/kg。结论:银莲花素A在体内外均具有较好的抑瘤作用,体内可抑制小鼠移植瘤的生长,是一个有潜力的抗癌药物。 展开更多
关键词 两头尖 银莲花素a 抑瘤活性 s180细胞 H22细胞 u14细胞 小鼠 移植瘤
下载PDF
大别北麓汤家坪花岗斑岩锆石LA-ICPMS U-Pb定年和岩石地球化学特征及其对岩石成因的制约 被引量:45
17
作者 魏庆国 高昕宇 +2 位作者 赵太平 陈伟 杨岳衡 《岩石学报》 SCIE EI CAS CSCD 北大核心 2010年第5期1550-1562,共13页
河南商城县汤家坪花岗斑岩产于大别造山带北麓,岩体位于早白垩世达权店花岗岩体的南缘。岩体斑晶含量占10%左右,主要由钾长石、斜长石和石英组成,基质主要由钾长石、斜长石、石英和少量黑云母组成,副矿物主要为磁铁矿、赤铁矿、锆石。... 河南商城县汤家坪花岗斑岩产于大别造山带北麓,岩体位于早白垩世达权店花岗岩体的南缘。岩体斑晶含量占10%左右,主要由钾长石、斜长石和石英组成,基质主要由钾长石、斜长石、石英和少量黑云母组成,副矿物主要为磁铁矿、赤铁矿、锆石。花岗斑岩中锆石U-Pb年龄为121.6±4.6Ma,为早白垩世中晚期。汤家坪花岗斑岩含白云母,无角闪石,具高硅(SiO2>72%)、高碱(Na2O+K2O>7.4%)的特征,铝饱和指数(ACNK)为0.99~1.18,轻稀土富集、重稀土亏损(La/Yb)N=10.9~44.5,明显亏损Eu(δEu=0.40~0.58)、Sr、Ba、Nb等。P2O5与SiO2含量呈正相关关系、Pb与SiO2含量呈负相关关系、Y、Th随Rb升高而降低,属弱过铝质高分异S型花岗岩。汤家坪花岗斑岩εHf(t)(-17.6~-10.4)和εNd(t)(-15.5~-13.7)值均显示出壳源特征,tDM2(Hf)和tDM2(Nd)分别为1843~2281Ma和2034~2178Ma,反映汤家坪花岗斑岩来源于古老地壳物质的重熔,中等的初始Sr同位素指示源岩中可能有部分低成熟度地壳物质加入。结合稀土元素特征,认为汤家坪花岗斑岩源岩来源较深,主要源于下地壳物质。 展开更多
关键词 汤家坪花岗斑岩 高分异s型花岗岩 锆石u-Pb定年 Hf同位素 下地壳部分熔融
下载PDF
铜陵地区焦冲金硫矿床闪长玢岩锆石LA-ICP-MS U-Pb年龄及其地质意义 被引量:6
18
作者 阙朝阳 吴淦国 +4 位作者 张达 张志辉 狄永军 方红薇 袁琴 《矿床地质》 CAS CSCD 北大核心 2013年第6期1221-1235,共15页
铜陵矿集区内广泛分布的铁铜硫金矿床被认为与中生代发生的大规模成岩作用密切相关,其中形成于140~150Ma之间的晚侏罗世高钾钙碱性岩体是主要的成矿岩体。文章选取铜陵焦冲金硫矿区与成矿相关的闪长玢岩开展了锆石LA-ICP—MSU—Pb同... 铜陵矿集区内广泛分布的铁铜硫金矿床被认为与中生代发生的大规模成岩作用密切相关,其中形成于140~150Ma之间的晚侏罗世高钾钙碱性岩体是主要的成矿岩体。文章选取铜陵焦冲金硫矿区与成矿相关的闪长玢岩开展了锆石LA-ICP—MSU—Pb同位素年代学研究,测得闪长玢岩LA-ICP—MS锆石U_Pb同位素年龄为(128.0±2。2)Ma,表明铜陵地区除晚侏罗世与大规模成矿作用相关的高钾钙碱性岩浆作用外,还存在一期早白垩世与金硫多金属成矿作用相关的岩浆活动。4个中一晚石炭世岩浆锆石一致年龄(309~328Ma)表明该区可能存在海西期的岩浆作用,但其规模、背景及与成矿的关系还需进一步研究。其他2组继承岩浆成因锆石核的一致性年龄(1870--1931Ma、600--808Ma)表明铜陵地区与扬子克拉通一样存在明显的古元古代及新元古代的岩浆作用。 展开更多
关键词 地球化学 IaICP-Msu-Pb年龄 锆石 闪长玢岩 焦冲金硫矿床 铜陵
下载PDF
黑龙江完达山地区358高地岩金矿床花岗斑岩LA-ICP-MS锆石U-Pb定年及其地质意义 被引量:7
19
作者 王庆磊 杨言辰 +3 位作者 李骞 马晓阳 谈艳 张国宾 《地质通报》 CAS CSCD 北大核心 2015年第12期2171-2180,共10页
选取黑龙江省完达山地区358高地与成矿关系密切的花岗斑岩,进行系统的地质、岩相学、元素地球化学及LA-ICP-MS锆石U-Pb定年研究。结果显示:花岗斑岩具有富硅、钠、钾、铝,贫镁、钙的特征,里特曼指数(σ)为1.12~2.00(σ〈3.3),A/NK... 选取黑龙江省完达山地区358高地与成矿关系密切的花岗斑岩,进行系统的地质、岩相学、元素地球化学及LA-ICP-MS锆石U-Pb定年研究。结果显示:花岗斑岩具有富硅、钠、钾、铝,贫镁、钙的特征,里特曼指数(σ)为1.12~2.00(σ〈3.3),A/NK为1.36~2.00,A/CNK为1.11~1.93(A/CNK〉1.1);富集大离子亲石元素,亏损Nb、Ta,严重亏损Sr、P、Ti;轻稀土元素富集,重稀土元素亏损,具有负Eu异常。这些特征揭示,花岗斑岩是过铝质的S型花岗岩,岩浆来源可能为壳源。LA-ICP-MS锆石定年获得花岗斑岩的成岩年龄为128±1Ma,推断金矿成矿时代应为早白垩世晚期。构造判别图解显示,花岗斑岩具有碰撞后花岗岩的特征,斑岩体的形成很可能与太平洋板块俯冲作用后的伸展体制有密切关系。 展开更多
关键词 完达山地区 La-ICP-Ms锆石u-PB定年 s型花岗岩 碰撞后伸展
下载PDF
基于STC12C5A60S2的U盘音频播放器设计 被引量:3
20
作者 杨舰 纪绿彬 《电子科技》 2011年第10期24-27,共4页
设计了一个基于STC12C5A60S2的U盘音频播放器,介绍了播放器的设计思路和原理框图,分别就播放器的3个模块给出具体的实现电路,并提供了软件程序流程图。运行结果表明,播放器实现了预期功能,且具有较高的性价比和可拓性。
关键词 u MP3播放器 sTC12C5a60s2 Vs1003
下载PDF
上一页 1 2 125 下一页 到第
使用帮助 返回顶部