Yi Cui

Bio: Yi Cui is an academic researcher from Stanford University. The author has contributed to research in topics: Anode & Lithium. The author has an hindex of 220, co-authored 1015 publications receiving 199725 citations. Previous affiliations of Yi Cui include KAIST & University of California, Berkeley.

Generation and electric control of spin–valley-coupled circular photogalvanic current in WSe2

Abstract: The valley degree of freedom in layered transition-metal dichalcogenides provides an opportunity to extend the functionalities of spintronics and valleytronics devices. The achievement of spin-coupled valley polarization induced by the non-equilibrium charge-carrier imbalance between two degenerate and inequivalent valleys has been demonstrated theoretically and by optical experiments. However, the generation of a valley and spin current with the valley polarization in transition-metal dichalcogenides remains elusive. Here we demonstrate a spin-coupled valley photocurrent, within an electric-double-layer transistor based on WSe2, whose direction and magnitude depend on the degree of circular polarization of the incident radiation and can be further modulated with an external electric field. This room-temperature generation and electric control of a valley and spin photocurrent provides a new property of electrons in transition-metal dichalcogenide systems, and thereby enables additional degrees of control for quantum-confined spintronic devices. A spin- and valley-polarized photocurrent is generated, in an electric double-layer transistor, with a direction and magnitude that depends on the degree of circular polarization of the incident radiation and on an external electric field.

Effects of Polymer Coatings on Electrodeposited Lithium Metal

Abstract: The electrodeposition of lithium metal is a key process in next-generation, high energy density storage devices. However, the high reactivity of the lithium metal causes short cycling lifetimes and dendrite growth that can pose a serious safety issue. Recently, a number of approaches have been pursued to stabilize the lithium metal–electrolyte interface, including soft polymeric coatings that have shown the ability to enable high-rate and high-capacity lithium metal cycling, but a clear understanding of how to design and modify these coatings has not yet been established. In this work, we studied the effects of several polymers with systematically varied chemical and mechanical properties as coatings on the lithium metal anode. By examining the early stages of lithium metal deposition, we determine that the morphology of the lithium particles is strongly influenced by the chemistry of the polymer coating. We have identified polymer dielectric constant and surface energy as two key descriptors of the lithi...

Avoiding short circuits from zinc metal dendrites in anode by backside-plating configuration.

Abstract: Portable power sources and grid-scale storage both require batteries combining high energy density and low cost. Zinc metal battery systems are attractive due to the low cost of zinc and its high charge-storage capacity. However, under repeated plating and stripping, zinc metal anodes undergo a well-known problem, zinc dendrite formation, causing internal shorting. Here we show a backside-plating configuration that enables long-term cycling of zinc metal batteries without shorting. We demonstrate 800 stable cycles of nickel-zinc batteries with good power rate (20 mA cm(-2), 20 C rate for our anodes). Such a backside-plating method can be applied to not only zinc metal systems but also other metal-based electrodes suffering from internal short circuits.

Roll-to-Roll Transfer of Electrospun Nanofiber Film for High-Efficiency Transparent Air Filter

Abstract: Particulate matter (PM) pollution in air has become a serious environmental issue calling for new type of filter technologies. Recently, we have demonstrated a highly efficient air filter by direct electrospinning of polymer fibers onto supporting mesh although its throughput is limited. Here, we demonstrate a high throughput method based on fast transfer of electrospun nanofiber film from roughed metal foil to a receiving mesh substrate. Compared with the direct electrospinning method, the transfer method is 10 times faster and has better filtration performance at the same transmittance, owing to the uniformity of transferred nanofiber film (>99.97% removal of PM2.5 at ∼73% of transmittance). With these advantages, large area freestanding nanofiber film and roll-to-roll production of air filter are demonstrated.

A Three‐Dimensionally Interconnected Carbon Nanotube–Conducting Polymer Hydrogel Network for High‐Performance Flexible Battery Electrodes

Abstract: High-performance flexible energy-storage devices have great potential as power sources for wearable electronics. One major limitation to the realization of these applications is the lack of flexible electrodes with excellent mechanical and electrochemical properties. Currently employed batteries and supercapacitors are mainly based on electrodes that are not flexible enough for these purposes. Here, a three-dimensionally interconnected hybrid hydrogel system based on carbon nanotube (CNT)-conductive polymer network architecture is reported for high-performance flexible lithium ion battery electrodes. Unlike previously reported conducting polymers (e.g., polyaniline, polypyrrole, polythiophene), which are mechanically fragile and incompatible with aqueous solution processing, this interpenetrating network of the CNT-conducting polymer hydrogel exibits good mechanical properties, high conductivity, and facile ion transport, leading to facile electrode kinetics and high strain tolerance during electrode volume change. A high-rate capability for TiO2 and high cycling stability for SiNP electrodes are reported. Typically, the flexible TiO2 electrodes achieved a capacity of 76 mAh g–1 in 40 s of charge/discharge and a high areal capacity of 2.2 mAh cm–2 can be obtained for flexible SiNP-based electrodes at 0.1C rate. This simple yet efficient solution process is promising for the fabrication of a variety of high performance flexible electrodes.

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。