摘要：MnO2/carbon nanocomposites with hierarchical pore structure and controllable MnO2 loading have been synthesized using a self-limiting growth method. This was achieved by the redox reactions of KMnO4 with sacrificed carbon su.s.rates that contain hierarchical pores. The unique pore structure allows the synthesis of nanocomposites with tunable MnO2 loading up to 83 wt.%. The specific capacitance of the nanocomposites increased with the MnO2 loading; the conductivity measured by electrochemical impedance spectroscopy, on the other hand, decreased with increasing MnO2 loading. Optimization of the MnO2 loading resulted in nanocomposites with high specific capacitance and excellent rate capability. This work provides important fundamental understanding which will facilitate the design and fabrication of high-performance supercapacitor materials for a large variety of applications.

摘要：Highly active and low-cost catalysts for electrochemical reactions such as the hydrogen evolution reaction （HER） are crucial for the development of efficient energy conversion and storage technologies. Theoretical simulations have been instrumental in revealing the correlations between the electronic structure of materials and their catalytic activity, and guide the prediction and development of improved catalysts. However, difficulties in accurately engineering the desired atomic sites lead to challenges in making direct comparisons between experi- mental and theoretical results. In Mos2, the Mo-edge has been demonstrated to be active for HER whereas the s-edge is inert. using a computational descriptor- based approach, we predict that by incorporating transition metal atoms （Fe, Co, Ni, or Cu） the s-edge site should also become HER active. Vertically standing, edge-terminated Mos2 nanofilms provide a well-defined model system for verifying these predictions. The transition metal doped Mos2 nanofilms show an increase in exchange current densities by at least two-fold, in agreement with the theoretical calculations. This work opens up further opportunities for improving electrochemical catalysts by incorporating promoters into particular atomic sites, and for using well-defined systems in order to understand the origin of the promotion effects.

摘要：The Advanced Photon source （APs） at Argonne National Laboratory is considering the development of a superconducting linac-based fourth-generation hard X-ray source to meet future scientific needs of the hard X-ray user community. This work specifically focuses on the design of an optimized 5-cell superconducting radio-frequency structure well suited for a high-energy, high-beam-current energy recovery linac. The cavity design parameters are based on the APs storage ring nominal 7 GeV and 100 mA beam operation. A high-current 5-cell cw superconducting cavity operating at 1.4 GHz has been designed. In order to achieve a high current, the accelerating cavity shape has been optimized and large end-cell beam pipes have been adopted. The beam break-up threshold of the cavity has been estimated using the code TDBBu, which predicts a high threshold beam current for a 7 GeV energy recovery linac model. A copper prototype cavity has been fabricated that uses half-cell modules, initially assembled by clamping the cells together.

摘要：The recent proliferation of the 3D reflection seismic method into the near-surface area of geophysical applications, especially in response to the emergence of the need to comprehensively characterize and monitor near-surface carbon dioxide sequ.s.ration in shallow saline aquifers around the world, justifies the emphasis on cost-effective and robust quality control and assurance （QC/QA） workflow of 3D seismic data preprocessing that is suitable for near-surface applications. The main purpose of our seismic data preprocessing QC is to enable the use of appropriate header information, data that are free of noise-dominated traces, and/or flawed vertical stacking in su.s.quent processing steps. In this article, I provide an account of utilizing survey design specifications, noise properties, first breaks, and normal moveout for rapid and thorough graphical QC/QA diagnostics, which are easy to apply and efficient in the diagnosis of inconsistencies. A correlated vibroseis time-lapse 3D-seismic data set from a CO2-flood monitoring survey is used for demonstrating QC diagnostics. An important by-product of the QC workflow is establishing the number of layers for a refraction statics model in a data-driven graphical manner that capitalizes on the spatial coverage of the 3D seismic data.

摘要：Anion exchange membrane(AEM)fuel cells have gained great attention partially due to the advantage of using non-precious metal as ***,the reaction kinetics of hydrogen oxidation reaction(HOR)is two orders of magnitude slower in alkaline systems than in *** understand the slower kinetics of HOR in base,two major theories have been proposed,such as(1)pH dependent hydrogen binding energy as a major descriptor for HOR;and(2)bifunctional theory based on the contributions of both hydrogen and hydroxide adsorption for HOR in alkaline ***,we discu.s.the possible HOR mechanisms in alkaline electrolytes with the corresponding change in their Tafel *** from the traditional Tafel-Volmer and Heyrovsky-Volmer HOR mechanisms,the recently proposed hydroxide adsorption step is also discu.s.d to illustrate the difference in HOR mechanisms in acid and *** further summarize the representative works of alkaline HOR catalyst design(e.g.,precious metals,alloy,intermetallic materials,Ni-based alloys,carbides,nitrides,etc.),and briefly describe their fundamental HOR reaction mechanism to emphasize the difference in elementary reaction steps in alkaline *** strategy of strengthening local interaction that facilitates both H2 desorption and Hads+OHads recombination is finally proposed for future HOR catalyst design in alkaline environment.

摘要：There has been an intensive international effort to develop high-order Computational Fluid Dynamics(CFD) methods into design tools in aerospace engineering during the last one and half decades. These methods offer the potential to significantly improve solution accuracy and efficiency for vortex dominated turbulent flows. Enough progresses have been made in algorithm development, mesh generation and parallel computing that these methods are on the verge of being applied in a production design environment. since many review papers have been written on the subject, I decide to offer a personal perspective on the state-of-the-art in high-order CFD methods and the challenges that must be overcome.

摘要：Cerium oxide(ceria)plays an important and fascinating role in heterogeneous catalysis as illustrated by its versatile use as a catalyst,a catalyst support,or a promotor in various oxidation and reduction *** to these reactions is the rich defect chemistry,facile redox capability,and unusual acid-base properties of *** the unique redox and acid-base properties of ceria is essential to build the structure-catalysis relationship so that improved catalytic functions can be achieved for ceria-based *** the characterization toolbox,spectroscopic approach indisputably stands out for its unparalleled power in offering chemical insights into the surface properties of ceria at atomic and molecular *** this review,we summarize advances in revealing the redox and acid-base properties of ceria via a variety of spectroscopic methods including optical,X-ray,neutron,electronic and nuclear *** direct spectroscopy characterization and its coupling with probe molecules are analyzed to illustrate how the nature,strength and density of different surface sites are influenced by the pretreatment,the morphology and size of ceria *** directions in taking advantage of in situ/operando spectroscopy for better understanding the catalysis of ceria-based materials are proposed in the summary and outlook section.

摘要：An account of recent work on supported single‐atom catalyst design is given here for reactions as diverse as the low‐temperature water‐gas shift,methanol steam reforming,selective ethanol dehydrogenation,and selective hydrogenation of alkynes and *** is of fundamental interest to investigate the intrinsic activity and selectivity of the active metal atom site and compare them to the properties of the corresponding metal nanoparticles and sub‐nm *** is also important to understand what constitutes a stable active metal atom site in the various reaction environments,and maximize their loadings to allow us to design robust catalysts for industrial *** activity and stability studies,ideally following the evolution of the active site as a function of catalyst treatment in real time are *** characterization methods with atomic resolution will play a key role here and will be used to guide the design of new catalysts.

摘要：Angular-momentum-projected energy surface calculations for A ≈ 110 nuclei indicate three distinct energy minima occurring at different angular-momenta. These correspond to normal, super-, and hy- per-deformed shapes coexisting in one nucleus. 110Pd is studied in detail, with a quantitative prediction on super- and hyper-deformed spectra by the Projected shell Model calculation. It is found that several other neighboring nuclei in the A-110 mass region, with the neutron number around 64, also exhibit clear super- and hyper-deformation minima in the projected calculation.

摘要：Oxide heterointerface is a platform to create unprecedented two-dimensional electron gas, superconductivity and ferromagnetism, arising from a polar discontinuity at the interface. In particular, the ability to tune these intriguing effects paves a way to elucidate their fundamental physics and to develop novel electronic/magnetic devices. In this work, we report for the first time that a ferroelectric polarization screening at srTiO_(3)/PbTiO_(3) interface is able to drive an electronic construction of Ti atom, giving rise to room-temperature ferromagnetism. surprisingly, such ferromagnetism can be switched to antiferromagnetism by applying a magnetic field, which is reversible. A coupling of itinerant electrons with local moments at interfacial Ti3d orbital was proposed to explain the magnetism. The localization of the itinerant electrons under a magnetic field is responsible for the suppression of magnetism. These findings provide new insights into interfacial magnetism and their control by magnetic field relevant interfacial electrons promising for device applications.