Dong Wang

Bio: Dong Wang is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Scanning tunneling microscope & Medicine. The author has an hindex of 49, co-authored 491 publications receiving 9970 citations. Previous affiliations of Dong Wang include University of Science and Technology of China & Shanghai University.

Generation of ultrashort coherent radiation based on a laser plasma accelerator.

Abstract: A laser plasma accelerator (LPA) has the potential to realize compact free-electron laser (FEL) radiation at the regular laboratory scale. However, large initial angular divergence and energy spread dramatically hinder ways to transport the beam and realize FEL radiation. Although methods have been proposed to solve these problems, the relatively large jitter, including transverse position jitter and energy jitter, still limits the advance of these experiments. In this paper a simple method to realize coherent harmonic generation based on a LPA beam is proposed. The scheme is very compact, adopting a high-power laser split from the driver laser, a short modulator and a short radiator which has a great tolerance to these typical types of jitter. Numerical simulations indicate that coherent third-harmonic radiation with gigawatt-level power and single spike spectra can be obtained, verifying the feasibility of the scheme and indicating the capability to generate ultrashort fully coherent radiation.

Influence of Ta on the intermediate temperature creep behavior of a single crystal superalloy

Abstract: The influence of Ta on the intermediate temperature creep behavior and deformation mechanism in a Ni-based single crystal superalloy has been investigated at 760 oC and 750 MPa. The results indicate that there is a significant increasing of creep rupture life after the addition of Ta. Lattice misfit between γ and γ′ phase at 760 oC increases in the Ta-containing alloy. Microstructure showed that the formation of stacking faults in the γ matrix and denser dislocation network at the γ/γ′ interfaces caused by Ta addition are found during the primary creep stage. And a large amount of stacking fault locks which act as an important pattern in the strengthening generate in the γ′ precipitates, resulting in a lower steady state creep rate and longer steady state creep life in Ta-containing alloy. And possible formation mechanism of the stacking fault locks is also discussed.

Si@Cu@Au AFM tips for tip-enhanced Raman spectrum

Abstract: Tip-enhanced Raman spectrum (TERS) is a scanning probe technique for acquiring chemical information at high spatial resolution and with high chemical sensitivity. The sensitivity of TERS with atomic force microscopy (AFM) system is mainly determined by the metalized tips. Here, we report a fabrication protocol for AFM-TERS tips that incorporate a copper (Cu) primer film between a gold (Au) layer and a Si AFM tips. They were fabricated by coating the Si tip with a 2 nm Cu layer prior to adding a 20 nm Au layer. For top illumination TERS experiments, these tips exhibited superior TERS performance relative to that observed for tips coated with Au only. Samples included graphene, thiophenol and brilliant cresyl blue. The results may derive from the surface roughness of the tip apex and a Cu/Au synergism of local surface plasmon resonances.

Shedding light on the cell biology of extracellular vesicles.

Abstract: Extracellular vesicles are a heterogeneous group of cell-derived membranous structures comprising exosomes and microvesicles, which originate from the endosomal system or which are shed from the plasma membrane, respectively They are present in biological fluids and are involved in multiple physiological and pathological processes Extracellular vesicles are now considered as an additional mechanism for intercellular communication, allowing cells to exchange proteins, lipids and genetic material Knowledge of the cellular processes that govern extracellular vesicle biology is essential to shed light on the physiological and pathological functions of these vesicles as well as on clinical applications involving their use and/or analysis However, in this expanding field, much remains unknown regarding the origin, biogenesis, secretion, targeting and fate of these vesicles

Toward Safe Lithium Metal Anode in Rechargeable Batteries: A Review.

Abstract: The lithium metal battery is strongly considered to be one of the most promising candidates for high-energy-density energy storage devices in our modern and technology-based society. However, uncontrollable lithium dendrite growth induces poor cycling efficiency and severe safety concerns, dragging lithium metal batteries out of practical applications. This review presents a comprehensive overview of the lithium metal anode and its dendritic lithium growth. First, the working principles and technical challenges of a lithium metal anode are underscored. Specific attention is paid to the mechanistic understandings and quantitative models for solid electrolyte interphase (SEI) formation, lithium dendrite nucleation, and growth. On the basis of previous theoretical understanding and analysis, recently proposed strategies to suppress dendrite growth of lithium metal anode and some other metal anodes are reviewed. A section dedicated to the potential of full-cell lithium metal batteries for practical applicatio...

Recent Advances in Ultrathin Two-Dimensional Nanomaterials

Abstract: Since the discovery of mechanically exfoliated graphene in 2004, research on ultrathin two-dimensional (2D) nanomaterials has grown exponentially in the fields of condensed matter physics, material science, chemistry, and nanotechnology. Highlighting their compelling physical, chemical, electronic, and optical properties, as well as their various potential applications, in this Review, we summarize the state-of-art progress on the ultrathin 2D nanomaterials with a particular emphasis on their recent advances. First, we introduce the unique advances on ultrathin 2D nanomaterials, followed by the description of their composition and crystal structures. The assortments of their synthetic methods are then summarized, including insights on their advantages and limitations, alongside some recommendations on suitable characterization techniques. We also discuss in detail the utilization of these ultrathin 2D nanomaterials for wide ranges of potential applications among the electronics/optoelectronics, electrocat...

Active sites of nitrogen-doped carbon materials for oxygen reduction reaction clarified using model catalysts

Abstract: Nitrogen (N)-doped carbon materials exhibit high electrocatalytic activity for the oxygen reduction reaction (ORR), which is essential for several renewable energy systems. However, the ORR active site (or sites) is unclear, which retards further developments of high-performance catalysts. Here, we characterized the ORR active site by using newly designed graphite (highly oriented pyrolitic graphite) model catalysts with well-defined π conjugation and well-controlled doping of N species. The ORR active site is created by pyridinic N. Carbon dioxide adsorption experiments indicated that pyridinic N also creates Lewis basic sites. The specific activities per pyridinic N in the HOPG model catalysts are comparable with those of N-doped graphene powder catalysts. Thus, the ORR active sites in N-doped carbon materials are carbon atoms with Lewis basicity next to pyridinic N.

Recent Advances in Electrocatalysts for Oxygen Reduction Reaction

Abstract: The recent advances in electrocatalysis for oxygen reduction reaction (ORR) for proton exchange membrane fuel cells (PEMFCs) are thoroughly reviewed. This comprehensive Review focuses on the low- and non-platinum electrocatalysts including advanced platinum alloys, core–shell structures, palladium-based catalysts, metal oxides and chalcogenides, carbon-based non-noble metal catalysts, and metal-free catalysts. The recent development of ORR electrocatalysts with novel structures and compositions is highlighted. The understandings of the correlation between the activity and the shape, size, composition, and synthesis method are summarized. For the carbon-based materials, their performance and stability in fuel cells and comparisons with those of platinum are documented. The research directions as well as perspectives on the further development of more active and less expensive electrocatalysts are provided.