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.

Phase transformations in materials studied by micro-Raman spectroscopy of indentations

Abstract: Phase transformations occurring in materials under high pressures are important for a wide range of problems in materials science and solid-state physics. Most of the results in this area have been...

Automated Scalpel Patterning of Solution Processed Thin Films for Fabrication of Transparent MXene Microsupercapacitors.

Abstract: A simple and generic strategy is proposed to pattern thin films deposited by a solution processable route. A soft approach based on an automated scalpel technique is developed to engrave thin films in a single step for sculpting functional planar devices. MXenes-the emerging family of 2D transition metal carbides and nitrides-combine metallic conductivity and hydrophilicity, enabling solution processing of transparent conducting electrodes (TCEs) under ambient conditions. Scalable dip coating is employed to process titanium carbide, Ti3 C2 , MXene thin films with excellent optoelectronic properties, achieving electrical Figure of merit up to 14. Automated scalpel engraving is adopted to fabricate transparent and semi-transparent MXene microsupercapacitors in a single step, hitherto not reported. Combining TCE and pseudocapacitive characteristics, MXene devices show excellent capacitive storage capabilities at high rates, without the aid of external metal current collectors. This technique allows for maskless patterning of solution processed thin films without losing intrinsic physicochemical properties and can be extended to fabricate heterostructured hybrid devices out of solution processable materials.

Carbide-derived carbons: a comparative study of porosity based on small-angle scattering and adsorption isotherms.

Abstract: Porous carbons have received much attention recently for potential applications in energy generation and storage, molecular sieving, and environmental remediation. Property optimization for specific applications rests largely on controlling the volume, size, and shape of the pores at the synthetic level. Direct atom-scale experiments which might accurately and reliably measure these quantities are problematic, so indirect methods such as gas sorption are generally employed. Here we apply a second indirect method, small-angle X-ray scattering (SAXS), to study porosity in carbide-derived carbons (CDC). The results qualitatively confirm and reinforce model-dependent conclusions drawn from gas sorption isotherms. In particular, both techniques indicate the onset of broad polydispersity under the same processing conditions for particular porous carbon materials.

Electrochemical Actuators Based on Two-Dimensional Ti3C2Tx (MXene).

Abstract: Electrochemical actuators are devices that convert electrical energy into mechanical energy via electrochemical processes. They are used in soft robotics, artificial muscles, micropumps, sensors, and other fields. The design of flexible and stable electrode materials remains a major challenge. MXenes, an emerging family of 2D materials, have found applications in energy storage. Here, we report an actuator device using MXene (Ti3C2Tx) as a flexible electrode material. The electrode in 1 M H2SO4 electrolyte exhibits a curvature change up to 0.083 mm-1 and strain of 0.29%. Meanwhile, the MXene-based actuator with a symmetric configuration separated by gel electrolyte (PVA-H2SO4) has curvature and strain changes up to 0.038 mm-1 and 0.26% with excellent retention after 10,000 cycles. In situ X-ray diffraction analysis demonstrates that the actuation mechanism is due to the expansion and shrinkage of the interlayer spacing of MXenes. This research shows promise of this new family of materials for electrochemical actuators.

New Insights into the Structure of Nanoporous Carbons from NMR, Raman, and Pair Distribution Function Analysis

Abstract: The structural characterization of nanoporous carbons is a challenging task as they generally lack long-range order and can exhibit diverse local structures Such characterization represents an important step toward understanding and improving the properties and functionality of porous carbons, yet few experimental techniques have been developed for this purpose Here we demonstrate the application of nuclear magnetic resonance (NMR) spectroscopy and pair distribution function (PDF) analysis as new tools to probe the local structures of porous carbons, alongside more conventional Raman spectroscopy Together, the PDFs and the Raman spectra allow the local chemical bonding to be probed, with the bonding becoming more ordered for carbide-derived carbons (CDCs) synthesized at higher temperatures The ring currents induced in the NMR experiment (and thus the observed NMR chemical shifts for adsorbed species) are strongly dependent on the size of the aromatic carbon domains We exploit this property and use co

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.