Tightly bound excitons in monolayer WSe2

Exciton binding energy and excited states in monolayers of tungsten diselenide (WSe2) are investigated using the combined linear absorption and two-photon photoluminescence excitation spectroscopy. The exciton binding energy is determined to be 0.37eV, which is about an order of magnitude larger than that in III-V semiconductor quantum wells and renders the exciton excited states observable even at room temperature. The exciton excitation spectrum with both experimentally determined one- and two-photon active states is distinct from the simple two-dimensional (2D) hydrogenic model. This result reveals significantly reduced and nonlocal dielectric screening of Coulomb interactions in 2D semiconductors. The observed large exciton binding energy will also have a significant impact on next-generation photonics and optoelectronics applications based on 2D atomic crystals.Comment: 19 pages, 4 figures, to appear in PR

Perancangan Media Promosi Angkringan Estoe Cafe Melalui Komunikasi Visual

Angkringan Estoe merupakan sebuah usaha dibidang kuliner yang berdiri pada tahun 2012 yang berlokasi di Jl. Raya Tampingan -Boja,Kabupaten Kendal,Jawa tengah,kafe yang berkonsep nuansa tradisional ini kalah bersaing dari kompetitornya. Kurangnya promosi dalam perusahaan menyebabkan kurangnya awareness dikalangan masyarakat. Untuk itu, Angkringan Estoe membutuhkan promosi yang berbeda dengan kafe lain agar lebih unggul daripada pesaingnya. Perancangan ini memberikan konsep promosi berdasarkan konsep Angkringan Estoe sebagai kafe yang mengutamakan kenyamanan homie,menu dan suasana tradisional. Dalam perancangan media promosi ini menggunakan metode pengumpulan data kualitatif dengan cara wawancara dengan pemilik dan pengelola Angkringan Estoe. Kegiatan promosi yang dilakukan nantinya menggunakan iklan visual dengan pilihan media yang ditentukan, dengan harapan dapat memperkenalkan kafe bernuansa tradisional yang diminati masyarakat terutama masyarakat Boja

N-doped hard/soft double-carbon-coated Na3V2(PO4)3 hybrid-porous microspheres with pseudocapacitive behaviour for ultrahigh power sodium-ion batteries

The development of sodium-ion batteries with high power density is highly challenging yet critically important in many applications. Herein, we develop sodium-ion batteries with ultrahigh power density by using N-doped hard/soft double-carbon-coated Na3V2(PO4)3 hybrid-porous microspheres as a cathode. A higher working potential of 3.4 V, superior rate capability (93 mA h g−1 at 10C, 81 mA h g−1 at 30C) as well as stable cycling performance (72.9% capacity retention at 10C after 1000 cycle) are simultaneously achieved. Very impressively, it can deliver pseudocapacitive behavior and a practical energy density of 317 W h kg−1 at a power density of 194 W kg−1, which also remains 73.5 W h kg−1 even at an ultrahigh power density of 12600 W kg−1. The superior performances can be ascribed to the hybrid-porous microsphere structure, which provide favorable kinetics for bath electron and Na+, large cathode-electrolyte contact area, as well as robust structural integrity. This design provides a promising pathway for developing low-cost sodium-ion batteries with high energy density as well as high power density

NaTi2(PO4)3/N‐Doped Hard Carbon Nanocomposites with Sandwich Structure for High‐Performance Na‐Ion Full Batteries

The well‐matched technology of cathode and anode in Na‐ion full batteries is highly challenging yet critically important in practical applications. Here, the high‐performance Na‐ion full batteries are developed by using NaTi2(PO4)3/N‐doped mesoporous hard carbon hybrid anode and porous Na3V2(PO4)3 cathode. The different anodes are designed for well‐matched Na‐ion full batteries. The unique sandwich and mesoporous structural features endow the hybrid anode with a high reversible capacity (240 mAh g−1 at 1 C), high rate performance (109.7 mAh g−1 at 100 C), ultrahigh energy/power densities (76.56 Wh kg−1/5104 W kg−1) and a long cycle‐life (capacity retention of 92.1 % after 1000 cycles at 100 C) in a half cell. In a full battery this hybrid anode can also deliver a higher capacitive contribution (79.5–87.7 %) and high energy/power densities (104 Wh kg−1/5256 W kg−1). This design provides a promising pathway for developing high performance and low‐cost Na‐ion full batteries

Robot Manipulation Planning Under Linear Temporal Logic Specifications

Automated planning for manipulation tasks is highly desirable, for it enables robot manipulators to be used by none robotics experts. This thesis presents one approach to solving manipulation planning for tasks expressed in linear temporal logic (ltl). This approach is based on the synergistic framework, which provides probabilistic completeness guarantees. Even though the synergistic framework has shown to work well for planning for ltl tasks in the navigation domain, it lacked an abstraction that can capture the high dimensionality of manipulation. This thesis enables manipulation planning using the synergistic framework by introducing a manipulation abstraction and modifying the interaction between task and motion planning in the framework. The modified framework is shown to be effectively in case studies in both simulation and physical systems. The case studies also show that the synergistic framework plans for manipulation problems more effective using the manipulation abstraction in comparison with a naive abstraction

Multigrid CHOMP with Local Smoothing

In recent years, CHOMP has found many applications in robotics research, as it combines\ud motion planning and optimization. Its flexibility in initial trajectory enables it to solve many\ud complex problems without pre- or post-processing. Even though using CHOMP under constraints\ud has been investigated, such algorithms are slow for large trajectories. In this paper,\ud we present Multigrid CHOMP with Local Smoothing, an algorithm to improve the runtime of\ud CHOMP under constraints without significantly reducing optimality. The effectiveness of this\ud algorithm is demonstrated in planning for three different problems, including door opening for\ud Hubo, a humanoid robot used for the DARPA Robotics Challenge