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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.


Papers
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TL;DR: Measurements of the conductivity of the dimeric 1,4-benzenedithiol (BDT) junction are reported using the scanning tunneling microscopy (STM)-based current-displacement I(s) method, finding the conductance to be almost two orders of magnitude lower than that of the monomer BDT junction.
Abstract: Understanding the electron transport between single molecules connected through weak interaction is of great importance for molecular electronics. In this paper, we report measurements of the conductivity of the dimeric 1,4-benzenedithiol (BDT) junction using the scanning tunneling microscopy (STM)-based current-displacement I(s) method. The conductance was measured to be 6.14×10(-6) G0 , a value almost two orders of magnitude lower than that of the monomer BDT junction. In control experiments, the probability of junction formation decreased with the presence of tris(2-chloroethyl) phosphate (TCEP), a reducing reagent for the disulfide bond. According to theoretical computations, the dihedral angle of the SS bond tends to take a perpendicular conformation. This non-conjugated structure localizes the electron distribution and accounts for the low conductivity of the disulfide linkage.

4 citations

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TL;DR: In this paper, the dendritic branching patterns at variable cross-sections in Ni-based single crystal (SX) castings of different generations were investigated using optical microscope (OM), electro probe microanalyzer (EPMA), differential scanning calorimeter (DSC), Thermo-Cal software and Pro-CAST software.
Abstract: Dendritic branching patterns at variable cross-sections in Ni-based single crystal (SX) castings of different generations were investigated using optical microscope (OM), electro probe microanalyzer (EPMA), differential scanning calorimeter (DSC), Thermo-Cal software and Pro-CAST software. Results show that the dendritic branching patterns are similar in outward platform in SXs of different generations. That is, the primary dendrites (PDs) are introduced into the platform by developing a series of secondary dendrites (SDs) to occupy the bottom of the platform, and the ternary dendrites (TDs) originating from these SDs grow upward to fill up the platform. With the SX generation increasing, the undercooling of melts in the inward platform increases significantly due to the increasing alloying elements and the segregation in the directional solidification (DS) process, and the growth velocity of the dendrite tip increases according to the dynamic model of dendrite growth, which is beneficial for the high-order dendrite development. The stronger dendritic branching ability is shown in the inward platform of the higher generation Ni-based SX.

4 citations

Journal ArticleDOI
TL;DR: The layered oxyselenides with the formula LnCrSe2O ( Ln = Ce-Nd) were synthesized via molten salt methods and Powder X-ray diffraction results confirm the phase purities of the as-synthesized compounds.
Abstract: The layered oxyselenides with the formula LnCrSe2O (Ln = Ce-Nd) were synthesized via molten salt methods. The isostructural compounds crystallize in the monoclinic space group of C2/m. The crystal structures feature ∞2[CrSe2O]3- motifs stacked along the a axis, which are separated by Ln3+ ions. The ∞2[CrSe2O]3- layers are composed of [Cr1Se6]9- and [Cr2Se4O2]9- octahedra via corner and edge sharing. Powder X-ray diffraction results confirm the phase purities of the as-synthesized compounds. LnCrSe2O (Ln = Ce-Nd) show typical antiferromagnetic ordering with TN = 125, 120, and 118 K, respectively. Heat capacity measurement for NdCrSe2O indicates that the Debye temperature is 278.4 K. Similar metal-to-semiconductor phase transitions were observed for LnCrSe2O (Ln = Ce-Nd) plates with transition temperatures of 115, 109, and 95 K, respectively. NdCrSe2O also possesses a magnetoresistance effect at low temperature (<25 K) with a significant positive magnetoresistance ∼ 16% at 2 K and 1 T.

4 citations

Journal ArticleDOI
TL;DR: In this paper, a series of catalysts made of Pt nanoparticles supported on reduced graphene oxides (Pt/RGO) were synthesized and tested in methanol oxidation reaction, aiming for optimizing the mass-specific activity of prepared Pt and RGO composites.
Abstract: Series of catalysts made of Pt nanoparticles supported on reduced graphene oxides (Pt/RGO) were synthesized and tested in methanol oxidation reaction, aiming for optimizing the mass-specific activity of prepared Pt/RGO composites. The loading amount of Pt is controlled through setting different reaction time and determined precisely by atomic absorption spectrophotometer. The structure of Pt/RGO composites is characterized by X-ray diffraction, transmission electron microscopy and Raman spectroscopy. The electrochemical testing data reveal that the Pt/RGO-mass-specific activity, judged by current density and long-term stability, is maximized in the sample in which cooperation of the Pt loading amount and electrochemical active surface area (ECSA) per amount of Pt is best optimized. The performance of the catalyst with smallest Pt particles or highest Pt loading amount is dragged down by either too less Pt loading or poor ECSA per amount of Pt. The results in this research demonstrate that the mass-normalized activity of whole catalyst, which is associated with the anticipated power output per amount of catalyst, could be enhanced significantly by deliberate tuning of fabrication process.

4 citations


Cited by
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TL;DR: Extracellular vesicles are now considered as an additional mechanism for intercellular communication, allowing cells to exchange proteins, lipids and genetic material.
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

4,241 citations

Journal ArticleDOI
TL;DR: This review presents a comprehensive overview of the lithium metal anode and its dendritic lithium growth, summarizing the theoretical and experimental achievements and endeavors to realize the practical applications of lithium metal batteries.
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...

3,812 citations

Journal ArticleDOI
TL;DR: The unique advances on ultrathin 2D nanomaterials are introduced, followed by the description of their composition and crystal structures, and the assortments of their synthetic methods are summarized.
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...

3,628 citations

Journal ArticleDOI
22 Jan 2016-Science
TL;DR: In this paper, the oxygen reduction reaction (ORR) active site was characterized by using newly designed graphite (highly oriented pyrolitic graphite) model catalysts with well-defined π conjugation and well-controlled doping of N species.
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.

3,201 citations

Journal ArticleDOI
TL;DR: 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.
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.

2,964 citations