Yury Gogotsi

Bio: Yury Gogotsi is an academic researcher from Drexel University. The author has contributed to research in topics: MXenes & Carbon. The author has an hindex of 171, co-authored 956 publications receiving 144520 citations. Previous affiliations of Yury Gogotsi include Qatar Airways & Clemson University.

Effects of structural disorder and surface chemistry on electric conductivity and capacitance of porous carbon electrodes

Abstract: This article reports on changes in electric double layer charge storage capacity as a function of surface chemistry and graphitic structure of porous carbon electrodes. By subjecting 20 nm to 2.0 μm sized carbide-derived carbons (CDCs) synthesized at 800 °C to high-temperature vacuum annealing at 700–1800 °C, we produce three-dimensional internal surface architectures with similar pore sizes and volumes but divergent surface chemistry and wall graphitization. Annealing increases carbon ordering and selectively removes functional groups, and both transformations affect conductivity and wettability. Contrary to an expected increase in gravimetric capacitance, we demonstrate no increases in charge storage despite increased conductivity and pore accessibility. At the same time, annealing improves the charge/discharge rates in EMIm-TFSI ionic liquid electrolyte. The annealing process eliminates faradaic reactions that limit the voltage window, but potentially accelerates catalytic breakdown of the ions themselves. We therefore corroborate the theory that surface groups and defects in the graphitic structure act as dopants that allow facile movement of ions into pores, improve screening in the superionic state, and affect the quantum capacitance contribution from the carbon structure.

Scalable Synthesis of Ultrathin Mn3N2 Exhibiting Room-Temperature Antiferromagnetism

Abstract: Ultrathin and 2D magnetic materials have attracted a great deal of attention recently due to their potential applications in spintronics. Only a handful of stable ultrathin magnetic materials have been reported, but their high-yield synthesis remains a challenge. Transition metal (e.g., manganese) nitrides are attractive candidates for spintronics due to their predicted high magnetic transition temperatures. Here, a lattice matching synthesis of ultrathin Mn3N2 is employed. Taking advantage of the lattice match between a KCl salt template and Mn3N2, this method yields the first ultrathin magnetic metal nitride via a solution-based route. Mn3N2 flakes show intrinsic magnetic behavior even at 300 K, enabling potential room-temperature applications. This synthesis procedure offers an approach to the discovery of other ultrathin or 2D metal nitrides.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Materials for electrochemical capacitors

Abstract: Electrochemical capacitors, also called supercapacitors, store energy using either ion adsorption (electrochemical double layer capacitors) or fast surface redox reactions (pseudo-capacitors). They can complement or replace batteries in electrical energy storage and harvesting applications, when high power delivery or uptake is needed. A notable improvement in performance has been achieved through recent advances in understanding charge storage mechanisms and the development of advanced nanostructured materials. The discovery that ion desolvation occurs in pores smaller than the solvated ions has led to higher capacitance for electrochemical double layer capacitors using carbon electrodes with subnanometre pores, and opened the door to designing high-energy density devices using a variety of electrolytes. Combination of pseudo-capacitive nanomaterials, including oxides, nitrides and polymers, with the latest generation of nanostructured lithium electrodes has brought the energy density of electrochemical capacitors closer to that of batteries. The use of carbon nanotubes has further advanced micro-electrochemical capacitors, enabling flexible and adaptable devices to be made. Mathematical modelling and simulation will be the key to success in designing tomorrow's high-energy and high-power devices.