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Carbon-supported PtCo_2Ni_2 alloy with enhanced activity and stability for oxygen reduction

Science China Materials 2015年第3期58卷 179-185页

作者：郑亚荣高敏锐李会会高强 Muhammad Nadeem Arshad hassan a.albar Tariq R.Sobahi 俞书宏 Division of Nanomaterials & Chemistry Hefei National Laboratory for Physical Science at MicroscaleCollaborative Innovation Center of Suzhou Nano Science and TechnologyDepartment of ChemistryUniversity of Science and Technology of China Center of Excellence for Advanced Materials Research King Abdulaziz University Chemistry Department Faculty of ScienceKing Abdulaziz University

The commercialization of proton exchange membrane fuel cells(PEMFCs) is still restricted by the well-known dilemma,that is,the heavy dependence of using expensive plantinum(Pt) catalyst to negotiate the sluggish oxygen reduction reaction(ORR) kinetics in fuel cell ***,a carbon-supported PtC o2Ni2 alloy catalyst with low Pt usage was synthesized via a simple method,which exhibited exceptional ORR activity with a more positive half-wave potential(E1/2) ~57 m V,which was more positive than the state-of-the-art Pt/C ***,the alloy catalyst performs excellent durability after 10,000 harsh cycles compared with that of Pt/C catalyst in acidic solution,which may be developed as a promising alternative for Ptbased catalysts in fuel cell technology.

关键词：合金催化剂 Pt ORR Ni Co HRTEM

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Diabatic Processes and the Generation of the Low-Level Potential Vorticity Anomaly of a Rainstorm in Saudi Arabia

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Atmospheric and Climate Sciences 2015年第3期5卷 275-291页

作者： H. Abdel-Basset A. K. AL-Khalaf A. albar Department of Astronomy and Meteorology Faculty of Science Al-Azhar University Cairo Egypt Department of Meteorology Faculty of Meteorology Environment and Arid Land Agriculture King Abdulaziz University Jeddah Kingdom of Saudi Arabia Presidency of Meteorology and Environment Jeddah Kingdom of Saudi Arabia

The diabatic heating is calculated, using the thermodynamic equation in isobaric coordinates, of a heavy rainstorm that developed over Jeddah, Saudi Arabia on 25 November 2009. Throughout the period of study, the horizontal heat advection is the dominant term and the vertical advection term is opposed by the adiabatic one. The contribution of the local temperature term to the change in diabatic heating is relatively very minimal. The presence of the Red Sea and its adjacent mountains suggest that the diabatic heating in the lower atmosphere on that rainy day is primarily due to the latent heat released by convection. The dynamics of the studied case is also investigated in terms of isobaric Potential Vorticity (PV). The results show that the heating region coincides with the location of the low-level PV anomaly. Ertel’s Potential Vorticity (EPV) generation estimates imply that condensation supplies a large enough source of moisture to account for the presence of the low-level EPV anomaly. The low-level diabatic heating-produced PV assisted in amplifying the surface thermal wave early in the rainstorm development and in the upper-level wave during the later stages of the system’s growth.

关键词： Potential Vorticity Diabatic Heating Moisture Processes Convection Heavy Rainstorm Saudi Arabia

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Radar Rainfall Estimation of a Severe Thunderstorm over Jeddah

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Atmospheric and Climate Sciences 2015年第3期5卷 302-316页

作者： Ayman Mohammed Hashem albar Abdulrahman Khalaf AL-Khalaf Heshmat Abdel-Basset Mohamed Presidency of Meteorology and Environment Jeddah Kingdom of Saudi Arabia Department of Meteorology Faculty of Meteorology Environment and Arid Land Agriculture King Abdulaziz University Jeddah Kingdom of Saudi Arabia Department of Astronomy and Meteorology Faculty of Science Al-Azhar University Cairo Egypt

The regular occurrence of flash floods over the region of Jeddah, Saudi Arabia in the past decade has highlighted the serious need for the development of early warning systems. Radar stations have been installed in Jeddah in the last decade whose active radius covers the Middle Western area of the country. Therefore, radar information and the associated the rainfall estimates are potentially useful components of an effective early warning system. Weather radar can potentially provide high-resolution spatial and temporal rainfall estimates that bring more accuracy to flood warnings as well as having applications in areas with insufficient rainfall stations coverage. Weather radar does not measure rainfall depth directly. An empirical relationship between reflectivity (Z) and rainfall rate (R), called the Z-R relationship (Z = ARb), is generally used to assess the rainfall depth. In this study, the rainfall events during August-September 2007 were analyzed to develop a Z-R relationship using the Spatial Probability Technique (SPT). This technique is based on a basic GIS function and the probability matching method. Using this technique, the Z-R pairs can be analyzed for both linear and empirical power relationships. It is found that the empirical power function is more appropriate to describe Z-R relationship than a linear function for the studied area. The method is applied with some success to the flooding event of November 25, 2009. However, the investigation of the Z-R relationship is only one step in the development of a warning system;further study of other parameters relevant to rainfall and flash flood occurrence is needed.

关键词： Rainfall Radar Reflectivity Z-R relationship Buffer Spatial GIS Jeddah Flood Saudi Arabia

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A Veteran Hotelier

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Beijing Review 2010年第17期53卷 39-39页

作者： Javier albar

Thirty five years ago,Javier albar was askedby his father, a hotelier at Hilton Madrid: "Would you like to go to a hotelschool in Switzerland?"The boy, who had a stronginterest in art

关键词： A Veteran Hotelier

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可以调和证据矛盾的新地幔对流模型

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世界地震译丛 2002年第3期33卷 52-58页

作者： F．albaréde R．D．vanderHilst 谢晓峰马禾青丁志峰不详宁夏回族自治区地震局

最近,提出了一种新的地幔对流模型,它与过去的标准模型相比要更接近实际一些。当然该模型还存在一些有争议的问题,不过我们认为,该模型可以调和不同研究领域矛盾的证据,因而为进一步研究对流提供一种新的构架。借助于我们最近的一些研... 详细信息

最近,提出了一种新的地幔对流模型,它与过去的标准模型相比要更接近实际一些。当然该模型还存在一些有争议的问题,不过我们认为,该模型可以调和不同研究领域矛盾的证据,因而为进一步研究对流提供一种新的构架。借助于我们最近的一些研究工作(albarede,1998)以及其他人的一些研究工作,我们对由Kellogg等(1999)、van der Hilst和Karason(1999)提出的模型作了更深入的研究。新的观点认为,一个深地层大致位于地幔中较低的第三层,该地层的化学成分明显地与其上覆的地层不同。这样的一个深地层将决定地球放热元素的实际部分,并有助于达到一些临界同位素体系的热平衡。化学变化和热密度变化间微妙的平衡产生了明显的动态地形,这一过程使得地震波监测复杂化,但却有利于沉降板块的穿过。热柱将形成于对流地幔的地层边界与上覆部分的过渡带中。若割裂气体消失、气体不完全消失或气体逸出的地层与从地震学角度已被证实的、被660km间断面分开的上下地幔之间的关系,要协调其他矛盾的证据看来还要颇费一番功夫。

关键词：地幔地震波沉降板块地震学

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多柔比星洗脱微球对经导管动脉化学栓塞的反应评估:肿瘤生物学和肝细胞癌复发移植的5年队列研究

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国际医学放射学杂志 2018年第3期 350-350页

作者： T.A.SANDow S.E.Arndt A.a.albar D.A.De Vun D.S.Kirsch J.M.Gimenez 吕晓虹 Department of Radiology Ochsner Health System

摘要目的评估肝细胞癌(HCC)进行肝移植病人经导管动脉化学栓塞(TACE)后肿瘤生物学和免疫学标志反应,为移植后复发风险制定最优移植前方案。材料与方法本回

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