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Moisture-Induced Non-Equilibrium Phase Segregation in Triple Cation Mixed Halide Perovskite Monitored by In Situ Characterization Techniques and Solid-State NMR 被引量:1
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作者 Mohammad Ali Akhavan Kazemi Nicolas Folastre +9 位作者 Parth Raval Michel Sliwa Jean Marie Vianney Nsanzimana Sema Golonu Arnaud Demortiere Jean Rousset Olivier Lafon Laurent Delevoye G.N.Manjunatha Reddy Frédéric Sauvage 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第2期185-194,共10页
Environmental stability is a major bottleneck of perovskite solar cells.Only a handful of studies are investigating the effect of moisture on the structural degradation of the absorber.They mostly rely on ex situ expe... Environmental stability is a major bottleneck of perovskite solar cells.Only a handful of studies are investigating the effect of moisture on the structural degradation of the absorber.They mostly rely on ex situ experiments and on completely degraded samples,which restrict the assessment on initial and final stage.By combining in situ X-ray diffraction under controlled 85%relative humidity,and live observations of the water-induced degradation using liquid-cell transmission electron microscopy,we reveal two competitive degradation paths leading on one hand to the decomposition of state-of-theart mixed cation/anion(Cs_(0.05)(MA_(0.17)FA_(0.83))_(0.95)Pb(Br_(0.17)I_(0.83))_(3)(CsMAFA)into PbI_(2) through a dissolution/recrystallization mechanism and,on the other hand,to a non-equilibrium phase segregation leading to CsPb_(2)Br_(5) and a Cesium-poor/iodide-rich Cs_(0.05)-x(MA_(0.17)FA_(0.83))_(0.95)Pb(Br_(0.17-2y)I_(0.83)+2y)_(3) perovskite.This degradation mechanism is corroborated at atomic-scale resolution through solid-state ^(1)H and ^(133)Cs NMR analysis.Exposure to moisture leads to a film containing important heterogeneities in terms of morphology,photoluminescence intensities,and lifetimes.Our results provide new insights and consensus that complex perovskite compositions,though very performant as champion devices,are comparatively metastable,a trait that limits the chances to achieve long-term stability. 展开更多
关键词 liquid-cell transmission electron microscopy moisture degradation perovskite stability phase segregation solid-state NMR
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无机抗菌剂的添加对新型自酸蚀处理剂黏结性能和颜色稳定性的影响 被引量:3
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作者 方明 陈吉华 +6 位作者 沈丽娟 熊宇 张凌 王迎捷 赵三军 王辉 HILDEBRAND Hartmut F 《中国美容医学》 CAS 2006年第8期888-892,共5页
目的:测试无机抗菌剂的添加对新型自酸蚀处理剂ESP黏结性能和颜色稳定性的影响。方法:6种无机抗菌剂分别加入ESP中,测试牛牙釉质粘结强度、边缘封闭性以及粘结样本颜色稳定性的变化。结果:抗菌剂添加比为0.5%对ESP牙釉质剪切强度无不利... 目的:测试无机抗菌剂的添加对新型自酸蚀处理剂ESP黏结性能和颜色稳定性的影响。方法:6种无机抗菌剂分别加入ESP中,测试牛牙釉质粘结强度、边缘封闭性以及粘结样本颜色稳定性的变化。结果:抗菌剂添加比为0.5%对ESP牙釉质剪切强度无不利影响(P>0.05),比例增至2.5%时,黏结强度呈不同程度降低。抗菌剂添加比为0.5%时,仅有一种抗菌剂的添加使冠方微渗漏指数较对照组显著增加(P<0.05)。粘结样本经不同处理以老化1年后颜色参数变化最为显著,但与ESP空白对照相比,抗菌剂添加后的颜色变化仍在临床可接受的范围之内。结论:控制适当的添加比例,5种受试的无机抗菌剂的添加对ESP的黏结性能可无显著影响,对颜色稳定性的影响在临床可接受的范围之内。 展开更多
关键词 无机抗菌剂 自酸蚀处理剂 黏结性能 颜色稳定性
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傅里叶变换红外光谱(FTIR)方法在南海定量矿物学研究中的应用:以MD01-2393孔为例 被引量:8
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作者 刘志飞 Christophe Colin Alain Trentesaux 《地球科学(中国地质大学学报)》 EI CAS CSCD 北大核心 2005年第1期25-29,共5页
傅里叶变换红外光谱 (FTIR)方法以其测量多种矿物绝对含量的能力在古环境研究中有很大的优势 .运用FTIR方法分析了南海南部湄公河口MD0 1 - 2 393孔的矿物成分含量 ,对比运用X射线衍射 (XRD)的半定量分析方法 ,研究了青藏高原东部和湄... 傅里叶变换红外光谱 (FTIR)方法以其测量多种矿物绝对含量的能力在古环境研究中有很大的优势 .运用FTIR方法分析了南海南部湄公河口MD0 1 - 2 393孔的矿物成分含量 ,对比运用X射线衍射 (XRD)的半定量分析方法 ,研究了青藏高原东部和湄公河盆地晚第四纪 1 90ka以来风化剥蚀演化历史 .结果显示 ,全岩高岭石 /石英和粘土粒级 ( <2 μm)高岭石 /蒙脱石比率可用作陆源区风化侵蚀的矿物学标志 .晚第四纪 190ka以来 ,青藏高原东部和湄公河盆地机械侵蚀作用在冰期比间冰期强 ,化学风化作用在间冰期比冰期强 ,揭示出亚洲季风气候驱动的风化剥蚀演化历史 .全新世期间 ,虽然全岩高岭石 /石英与粘土粒级 ( <2 μm)蒙脱石 /高岭石比率指示相同趋势的风化剥蚀作用 ,但全岩高岭石 /石英比率显示更强的机械侵蚀能力 。 展开更多
关键词 粘土矿物 傅里叶变换红外光谱(FTIR) 晚第四纪 湄公河 南海
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Does gastric atrophy exist in children? 被引量:6
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作者 Georges Dimitrov Frédéric Gottrand 《World Journal of Gastroenterology》 SCIE CAS CSCD 2006年第39期6274-6279,共6页
Several clinical reports confirmed that gastric atrophy is a pathology not only limited to adult patients. In pediatrics, it is most olden described in association with a H pylori infection but this bacteria does not ... Several clinical reports confirmed that gastric atrophy is a pathology not only limited to adult patients. In pediatrics, it is most olden described in association with a H pylori infection but this bacteria does not seem to be the only etiological factor of this preneoplastic state in children. The frequency of gastric atrophy and intestinal metaplasia in children are unknown because they are not systematically sought during upper gastrointestinal endoscopy. The lack of specific histological classification of children's gastropathies makes their diagnosis difficult for pathologists. Based on our knowledge to date, we think that it is necessary to describe, in detail, the natural course of this lesion during childhood. A close and prolonged clinical and endoscopic follow-up is important for children with gastric atrophy. 展开更多
关键词 Gastric atrophy GASTRITIS H pylori Intestinal metaplasia Gastric cancer CHILDREN
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Hepatitis C virus proteins 被引量:6
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作者 Jean Dubuisson 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第17期2406-2415,共10页
Hepatitis C virus (HCV) encodes a single polyprotein, which is processed by cellular and viral proteases to generate 10 polypeptides. The HCV genome also contains an overlapping +1 reading frame that may lead to the s... Hepatitis C virus (HCV) encodes a single polyprotein, which is processed by cellular and viral proteases to generate 10 polypeptides. The HCV genome also contains an overlapping +1 reading frame that may lead to the synthesis of an additional protein. Until recently, studies of HCV have been hampered by the lack of a productive cell culture system. Since the identification of HCV genome approximately 17 years ago, structural, biochemical and biological information on HCV proteins has mainly been obtained with proteins produced by heterologous expression systems. In addition, some functional studies have also been confirmed with replicon systems or with retroviral particles pseudotyped with HCV envelope glycoproteins. The data that have accumulated on HCV proteins begin to provide a framework for understanding the molecular mechanisms involved in the major steps of HCV life cycle. Moreover, the knowledge accumulated on HCV proteins is also leading to the development of antiviral drugs among which some are showing promising results in early- phase clinical trials. This review summarizes the current knowledge on the functions and biochemical features of HCV proteins. 展开更多
关键词 Hepatitis C virus Viral hepatitis VIRALPROTEINS Molecular virology
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Atmospheric Correction of SeaWiFS Data for the Retrieval of SuspendedSediment in East China Coastal Waters 被引量:3
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作者 廖迎娣 张玮 P.Y.Deschamps 《China Ocean Engineering》 SCIE EI 2005年第2期225-234,共10页
The data of SeaWiFS (Sea-Viewing Wide Field-of-View Sensor), installed on SeaStar, has been used to generate SSC (suspended sediment concentration) of complex and turbid coastal waters in China. In view of the problem... The data of SeaWiFS (Sea-Viewing Wide Field-of-View Sensor), installed on SeaStar, has been used to generate SSC (suspended sediment concentration) of complex and turbid coastal waters in China. In view of the problems of the SeaDAS (SeaWiFS Data Analysis System) algorithm applied to China coastal waters, a new atmospheric correction algorithm is discussed, developed, and used for the SSC of East China coastal waters. The advantages of the new algorithm are described through the comparison of the results from different algorithms. 展开更多
关键词 suspended sediment concentration Sea-Viewing Wide Field-of-View Sensor suspended sediment atmospheric correction China coastal waters
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Improvement of Fe(Ii)-Adsorption Capacity of Feooh-Coated Brick in Solutions, and Kinetics Aspects 被引量:1
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作者 Saint Charles Dehou Joseph Mabingui +2 位作者 Ludovic Lesven Michel Wartel Abdel Boughriet 《Journal of Water Resource and Protection》 2012年第7期464-473,共10页
The adsorbent, iron oxy-hydroxide coated brick, was used in the present work for removal of iron(II) from aqueous solutions. The adsorption performances of this composite were significantly improved when brick pellets... The adsorbent, iron oxy-hydroxide coated brick, was used in the present work for removal of iron(II) from aqueous solutions. The adsorption performances of this composite were significantly improved when brick pellets (as a support material) were pre-treated in a 6 M HCl solution at 90°C for 6 hours, when compared to untreated ones and those pre-washed in a 1M HCl solution at RT for 1 day. This phenomenon was attributed to larger surface areas measured for modified brick by BET, thus enabling a better FeOOH deposition. The ability of this new composite to better adsorb Fe2+ ions from synthetic solutions was evidenced from fixed-bed column experiments: data were compared to those obtained from raw brick and iron oxides - coated sand columns. The adsorption mechanism followed better pseudosecond-order reaction kinetics, suggesting a chemisorption process, and the rate constant increased with a temperature increase, revealing the endothermic nature of Fe(II) adsorption. Furthermore, the equilibrium data fitted the Langmuir isotherm model with a maximum monolayer sorption capacity Qmax = 0.669 mg/g and a Langmuir constant KL = 0.659 L/mg at room temperature. The activation energy (Ea) of Fe(II) adsorption and the changes in entropy (ΔS), enthalpy (ΔH) and free energy (ΔG) of activation were determined, with values suggesting the involvement of an activated chemical adsorption and an associative mechanism. 展开更多
关键词 BRICK FERROUS Ion IRON Oxyhydroxide Acid ACTIVATION Adsorption KINETICS ACTIVATION Energy Water Treatment
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An Approximation Method for a Maximum Likelihood Equation System and Application to the Analysis of Accidents Data
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作者 Assi N’Guessan Issa Cherif Geraldo Bezza Hafidi 《Open Journal of Statistics》 2017年第1期132-152,共21页
There exist many iterative methods for computing the maximum likelihood estimator but most of them suffer from one or several drawbacks such as the need to inverse a Hessian matrix and the need to find good initial ap... There exist many iterative methods for computing the maximum likelihood estimator but most of them suffer from one or several drawbacks such as the need to inverse a Hessian matrix and the need to find good initial approximations of the parameters that are unknown in practice. In this paper, we present an estimation method without matrix inversion based on a linear approximation of the likelihood equations in a neighborhood of the constrained maximum likelihood estimator. We obtain closed-form approximations of solutions and standard errors. Then, we propose an iterative algorithm which cycles through the components of the vector parameter and updates one component at a time. The initial solution, which is necessary to start the iterative procedure, is automated. The proposed algorithm is compared to some of the best iterative optimization algorithms available on R and MATLAB software through a simulation study and applied to the statistical analysis of a road safety measure. 展开更多
关键词 Constrained MAXIMUM LIKELIHOOD Partial Linear APPROXIMATION Schur’s COMPLEMENT ITERATIVE Algorithms Road Safety Measure MULTINOMIAL Model
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UDNS or LES, That Is the Question
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作者 Christoph Bosshard Michel O. Deville +1 位作者 Abdelouahab Dehbi Emmanuel Leriche 《Open Journal of Fluid Dynamics》 2015年第4期339-352,共14页
In the framework of the spectral element method, a comparison is carried out on turbulent first-and second-order statistics generated by large eddy simulation (LES), under-resolved (UDNS) and fully resolved direct num... In the framework of the spectral element method, a comparison is carried out on turbulent first-and second-order statistics generated by large eddy simulation (LES), under-resolved (UDNS) and fully resolved direct numerical simulation (DNS). The LES is based on classical models like the dynamic Smagorinsky approach or the approximate deconvolution method. Two test problems are solved: the lid-driven cubical cavity and the differentially heated cavity. With the DNS data as benchmark solutions, it is shown that the numerical results produced by the UDNS calculation are of the same accuracy, even in some cases of better quality, as the LES computations. The conclusion advocates the use of UDNS and calls for improvement of the available algorithms. 展开更多
关键词 Spectral Element Method Under-Resolved Direct Numerical SIMULATION Large EDDY SIMULATION Lid-Driven CAVITY DIFFERENTIALLY Heated CAVITY
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Experimental Analysis of UWB Signal Performance in a Constrained Environment for Railway Application
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作者 Ouafae Cohin Sara Ibenjellal +1 位作者 Fouzia Boukour Sylvie Baranowski 《Wireless Engineering and Technology》 2015年第4期79-86,共8页
In the railway application, in order to establish the communication between wagons, some technologies are proposed such as the ZigBee and HTN (Hybrid Networking Technology). However, these techniques have some limitat... In the railway application, in order to establish the communication between wagons, some technologies are proposed such as the ZigBee and HTN (Hybrid Networking Technology). However, these techniques have some limitations such as: the low data rate, non-secured transmission and interferences. The Ultra Wide Band (UWB) technology presents a good alternative and a good candidate for this application. In recent years, UWB communication systems have received significant attention from both the industry and the academia. In February 2002, the Federal Communications Commission (FCC) allocated 7500 MHz of spectrum (from 3.1 GHz to 10.6 GHz) for use by UWB devices. This ruling has helped to create new standardization efforts, like IEEE 802.15.3a, which focus on developing high speed wireless communication systems. The application of the UWB radio technique in the transport is a more recent topic that is thoroughly researched considering several factors including the nature of the transport propagation environment;the use of adequate transmitting/receiving duty cycle (LDC);the number of devices using UWB technology, the types and levels of interferences. Regulation bodies have considered these railway applications. Impulse Radio Ultra Wideband (IR-UWB) systems have been studied for their inherent advantages of coexistence with narrowband systems with high data rate over short distances with sufficiently small amount of transmitted power. The UWB systems are highly susceptible to interference between the coexisting narrowband systems because of very low transmission power. This paper considers the use of the UWB radio technology for railway application. In this paper, we evaluate the communication performance in constrained environment for the railway application. 展开更多
关键词 UWB CHANNEL MODEL CHANNEL SIMULATION SIMULATION Analysis
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脊髓灰质炎病毒特异性肠道抗体反应增强与婴儿肠道长双歧杆菌和短双歧杆菌的增多相一致:附一项随机、双盲、安慰剂对照试验
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作者 MulliéC. Yazourh A. +2 位作者 Thibault H. M.-B.Romond 阿明 《世界核心医学期刊文摘(儿科学分册)》 2005年第3期56-57,共2页
为了明确肠道双歧杆菌数量是否会影响儿童对脊髓灰质炎病毒的免疫反应,笔者进行了一项随机的安慰剂对照试验。从出生到4月龄,给予婴儿服用发酵剂儿童配方(FIF)或标准配方(安慰剂)。每月测量儿童粪便中的双歧杆菌的数目。在接种前及第2... 为了明确肠道双歧杆菌数量是否会影响儿童对脊髓灰质炎病毒的免疫反应,笔者进行了一项随机的安慰剂对照试验。从出生到4月龄,给予婴儿服用发酵剂儿童配方(FIF)或标准配方(安慰剂)。每月测量儿童粪便中的双歧杆菌的数目。在接种前及第2次疫苗注射后1 个月,对抗脊髓灰质炎病毒IgA抗体对Pentacoq的反应进行评价。共随机抽取30名儿童,有20名完成了研究(安慰剂组9名,FIF组11名)。FIF组中粪便双歧杆菌水平在4月龄时显著升高(P=0.0498)。而且FIF组婴儿在第4月龄时长双歧杆菌/婴儿双歧杆菌携带量较高(P=0.0399)。经过Pentacoq激发(P【0.001) 后,FIF组的抗脊髓灰质炎病毒IgA滴度显著升高(P【 0.02)。抗体滴度与双歧杆菌数目尤其与长双歧杆菌/ 婴儿双歧杆菌和短双歧杆菌数目(P【0.02)密切相关。体内寄生长双歧杆菌/婴儿双歧杆菌的婴儿同样显示具有较高的抗脊髓灰质炎病毒IgA水平(P【 0.02)。综上所述,目前的结果显示婴儿的抗脊髓灰质炎病毒反应能通过服用发酵配方所激发,该配方有利于肠道双歧杆菌生长。这种对免疫系统的作用是来源于配方中双歧杆菌(主要是长双歧杆菌/婴儿双歧杆菌和短双歧杆菌的激发)的作用还是牛奶发酵所产生的复合物(例如缩氨酸)的作用尚待研究。 展开更多
关键词 脊髓灰质炎病毒 疫苗注射 抗体反应 安慰剂对照 免疫反应 特异性 抗体滴度 体内寄生 缩氨酸 反应能
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珠江流域盆地表层沉积物的黏土矿物及其对南海沉积物的贡献 被引量:41
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作者 刘志飞 C.Colin +3 位作者 黄维 陈忠 A.Trentesaux 陈建芳 《科学通报》 EI CAS CSCD 北大核心 2007年第4期448-456,共9页
黏土矿物以其示踪洋流变化和揭示物源区陆地同时期气候变化的能力,近年来在南海东亚季风演化的研究中起到了重要作用.珠江作为南海北部陆源物质输入的重要河流之一,以往的研究还没有开展过详细的黏土矿物学工作.运用X射线衍射方法... 黏土矿物以其示踪洋流变化和揭示物源区陆地同时期气候变化的能力,近年来在南海东亚季风演化的研究中起到了重要作用.珠江作为南海北部陆源物质输入的重要河流之一,以往的研究还没有开展过详细的黏土矿物学工作.运用X射线衍射方法,系统地研究了珠江流域盆地(包括珠江主流、各支流和珠江口伶仃洋)表层沉积物的黏土矿物组合.结果显示,珠江流域盆地黏土矿物组合主要由高岭石(35%-65%)、绿泥石(20%~35%)和伊利石(12%~42%)组成,蒙脱石含量一般小于5%,区域分布上不具明显的差异性.但是,从珠江流域盆地到南海北部,高岭石含量持续降低,蒙脱石含量持续上升。伊利石含量也不断上升,伊利石化学指数递减,伊利石结晶度增强,这些特征都表明珠江流域盆地对南海北部黏土矿物的贡献主要是高岭石,其次是伊利石和绿泥石,基本不提供蒙脱石.研究认为。珠江对南海北部陆缘的黏土矿物贡献率最多为72%,而对北部陆坡的贡献率最多仅为15%.无论是冰期还是间冰期时期,高岭石都指示了珠江流域的机械侵蚀能力. 展开更多
关键词 黏土矿物 表层沉积物 物源区 东亚季风 珠江流域
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Chemometric analysis of femtosecond transient absorption spectroscopy data:Study of the photochromism of anils 被引量:3
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作者 Cyril RUCKEBUSCH Nicolas MOUTON +3 位作者 Thomas GLADYTZ Anika RENDELMANN Guy BUNTINX Michel SLIWA 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2010年第6期1024-1035,共12页
Chemometric methods are applied for the purpose of extracting relevant information from transient absorption spectroscopy data probing the photochromism of molecules from the family of salicylidene aniline. The proces... Chemometric methods are applied for the purpose of extracting relevant information from transient absorption spectroscopy data probing the photochromism of molecules from the family of salicylidene aniline. The process consists of an ultrafast excited state intramolecular proton transfer occurring from an enol form which is then followed by a cis-trans isomerization to finally reach a trans-keto photo-product. This work focuses on the potential of combining multivariate curve resolution for modeling pure profiles and two dimensional correlation spectroscopy data analysis for providing information on the dynamics of spectral features. The results obtained for one derivative of salicylidene aniline provide information regarding the number of species created after the proton transfer and characterization of their absorption spectra and their kinetics in the picosecond time scale. The spectral resolution of two cis-keto* forms is proposed for the first time. It is also found that both cis-keto* species are involved in the formation of the trans-keto photo-product. The main precursor of the trans-keto photo-product is the cis-keto* form which has the shortest characteristic time. 展开更多
关键词 MULTIVARIATE CURVE resolution two dimensional correlation SPECTROSCOPY FEMTOSECOND absorption PROTON transfer anils PHOTOCHROMISM
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Quality Assessment of Transcriptome Data Using Intrinsic Statistical Properties 被引量:2
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作者 Guillaume Brysbaert Franois-Xavier Pellay +1 位作者 Sebastian Noth Arndt Benecke 《Genomics, Proteomics & Bioinformatics》 SCIE CAS CSCD 2010年第1期57-71,共15页
In view of potential application to biomedical diagnosis, tight transcriptome data quality control is compulsory. Usually, quality control is achieved using labeling and hybridization controls added at different stage... In view of potential application to biomedical diagnosis, tight transcriptome data quality control is compulsory. Usually, quality control is achieved using labeling and hybridization controls added at different stages throughout the processing of the biologic RNA samples. These control measures, however, only reflect the performance of the individual technical manipulations during the entire process and have no bearing as to the continued integrity of the RNA sample itself. Here we demonstrate that intrinsic statistical properties of the resulting transcriptome data signal and signal-variance distributions and their invariance can be identified independently of the animal species studied and the labeling protocol used. From these invariant properties we have developed a data model, the pa- rameters of which can be estimatei:l from individual experiments and used to compute relative quality measures based on similarity with large reference datasets. These quality measures add supplementary, non-redundant in- formation to standard quality control estimates based on spike-in and hybridization controls, and are exploitable in data analysis. A software application for analyzing datasets as well as a reference dataset for AB 1700 arrays are provided. They should allow AB 1700 users to easily integrate this method into their analysis pipeline, and might instigate similar developments for other transcriptome platforms. 展开更多
关键词 TRANSCRIPTOME MICROARRAY quality control distribution properties STATISTICS SOFTWARE
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Palaeobiogeographical constraints on the distribution of foraminifers and rugose corals in the Carboniferous Tindouf Basin,South Morocco 被引量:1
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作者 Ian D.Somerville Pedro Cózar +3 位作者 Ismail Said Daniel Vachard Paula Medina-Varea Sergio Rodríguez 《Journal of Palaeogeography》 SCIE 2013年第1期1-18,共18页
The northern flank of the Tindouf Syncline in southern Morocco exhibits a continuous, well exposed Carboniferous succession with limestones of Late Asbian to Early Bashkirian age containing rich and diverse foraminife... The northern flank of the Tindouf Syncline in southern Morocco exhibits a continuous, well exposed Carboniferous succession with limestones of Late Asbian to Early Bashkirian age containing rich and diverse foraminiferal and rugose coral assemblages. Analysis of these assemblages provides new data on the relatively poorly known Saharan basins. The palaeobiogeographical relationship of the Tindouf Basin with other Palaeotethyan basins is complex. Although there is a predominance of cosmopolitan taxa for the Palaeotethys, it is recognized that there was an influence of basins from NW Europe, such as the UK and Ireland. Some taxa are recorded in both NW Europe and Tindouf without any characteristic contributions from intermediate basins in northern Morocco. The neighbouring Béchar Basin in Algeria presents distinct assemblages. The bulk of the data analyzed suggest that this sector of the western Palaeotethys can be subdivided into four palaeobiogeographical subprovinces: the Atlantic Subprovince (UK, Ireland, N France and Belgium), the Mediterranean Subprovince (Pyrenees, Montagne Noire, Betic Cordillera, Rif (N Morocco) and Balearic Islands), and the Saharan Subprovince (Béchar, Reggan, Ahnet-Mouydir and Tindouf). In between, mobile belts of mixed faunal assemblage characteristics are observed (e.g., SW Spain and Central Meseta) forming the West peri-Gondwanan Subprovince.Analysis of the Tindouf Basin faunas shows that, as in other Saharan basins, there is a high diversity and abundance of foraminiferal taxa, with a higher proportion of survivors and longer stratigraphic ranges; these features also are mirrored by rugose corals. This emphasizes the longevity of the carbonate platform in a tropical setting, where periodic transgressions introduced new assemblages, and oceanic currents are interpreted as one of the main controlling factors for the distribution of the taxa in these subprovinces. Moreover, not only were water temperatures on the platform higher, but also tectonic stability greater. It is considered that the effects of the first phases of the Gond-wanan glaciation were minimal on the Tindouf faunas. 展开更多
关键词 CARBONIFEROUS PALAEOBIOGEOGRAPHY new subprovinces FORAMINIFERS rugose corals Tindouf Basin North Africa
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Rainbow guiding of the lowest-order antisymmetric Lamb mode in phononic crystal plate
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作者 ZHAO JinFeng YUAN WeiTao +3 位作者 BONELLO Bernard DJAFARI-ROUHANI Bahram PAN YongDong ZHONG Zheng 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2019年第3期458-463,共6页
The modern acoustic circuits have experienced significant progress with the development of artificial structures, including phononic crystals, metamaterials or metasurfaces. Among the most intensive topics, the reconf... The modern acoustic circuits have experienced significant progress with the development of artificial structures, including phononic crystals, metamaterials or metasurfaces. Among the most intensive topics, the reconfigurable acoustic guides are achieved through several mechanisms. In this work, we report on the rainbow guiding for the lowest-order antisymmetric Lamb(A_0) mode in a phononic crystal plate, where the linear waveguides are constituted by erecting aligned pillars either solid or hollow. We show both numerically and experimentally that the whispering gallery modes(WGMs) in the hollow pillars can be generated by the defect mode that propagates in the waveguide. Then, the reemission of A_0 mode by the WGMs to the outer lateral areas can lead to spatial control of frequency selective wave guidance called "rainbow guiding". Our approach allows for an accurate control of the wave guiding and facilitates the integration of waveguides within other devices in the acoustic circuits. 展开更多
关键词 whispering GALLERY mode RAINBOW GUIDING phononic CRYSTAL
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Water content of the Xiaogulihe ultrapotassic volcanic rocks, NE China: implications for the source of the potassium-rich component
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作者 Huan Chen Qun-ke Xia Jannick Ingrin 《Science Bulletin》 SCIE EI CAS CSCD 2015年第16期1468-1470,共3页
Water has become an effective means to trace the mantle source of basaltic magmas recently. To investigate the source of the potassium-rich component in the Xiaogulihe ultrapotassic volcanic rocks of NE China, we meas... Water has become an effective means to trace the mantle source of basaltic magmas recently. To investigate the source of the potassium-rich component in the Xiaogulihe ultrapotassic volcanic rocks of NE China, we measured the water content of clinopyroxene (cpx) phenocrysts by Fourier transform infrared spectrometry and calculated the H2O content of the equilibrated melts according to the partition coefficients of H2O between cpx phenocrysts and basaltic melts. The estimated H2O content of the "primary" magmas is low (0.36 wt%-0.50 wt%), within the range of mid-ocean ridge basalts and ocean island basalts, while it is obviously lower than that of backarc basin basalts and island arc basalts. The calculated H20/Ce ratio of the "primary" magmas is about 15, which might be similar to that of the dehydrated sediments (〈100), but observably lower than that of the normal depleted mantle (DMM, H2O/Ce = 150-210). The low water content and especially low H2O/Ce ratio of the "primary" magmas demonstrate that the K-rich component of these ultrapotassic volcanic rocks seems unlikely tooriginate from K-bearing hydrous minerals (such as phlogopite) in metasomatic subcontinental lithospheric mantle. Combined with the low 206pb/204pb ratios, moderately high 87Sr/86Sr ratios of the bulk rocks and the high δ18O values of olivine phenocrysts, we suggest that the K-rich component in the mantle source of the Xiaogulihe ultrapotassic volcanic rocks may come from ancient continental-derived sediments which dehydrated significantly during subduction (e.g., dry K-hollandite). 展开更多
关键词 Ultrapotassic volcanic rocks NE China.Water content Dehydrated sediments
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