14,605 research outputs found
Induced Growth of Asymmetric Nanocantilever Arrays on Polar Surfaces
©2003 The American Physical Society. The electronic version of this article is the complete one and can be found online at: http://link.aps.org/doi/10.1103/PhysRevLett.91.185502DOI: 10.1103/PhysRevLett.91.185502We report that the Zn-terminated ZnO (0001) polar surface is chemically active and the oxygenterminated (0001) polar surface is inert in the growth of nanocantilever arrays. Longer and wider "comblike" nanocantilever arrays are grown from the (0001)-Zn surface, which is suggested to be a self-catalyzed process due to the enrichment of Zn at the growth front. The chemically inactive
(0001)-O surface typically does not initiate any growth, but controlling experimental conditions could lead to the growth of shorter and narrower nanocantilevers from the intersections between (0001)-O with (0110) surfaces
Light-Switchable Polymer Adhesive Based on Photoinduced Reversible Solid-to-Liquid Transitions
Experimental Investigation of Direct Expansion Dynamic Ice-on-coil Storage System Used in Residential Buildings
The reduction in electricity consumption of an ice-storage system in the daytime leads to financial savings for building owners and extension savings for a power plant and national economy. Great advancements have been made in domestic ice-storage systems due to the bigger peak-to-valley differences of electricity used in residential buildings. However, there are still some shortcomings that affect its widespread applications. The paper reports on an experimental investigation on a domestic direct expansion dynamic ice-on-coil storage system that overcame the disadvantages of static and dynamic ice-storage system. It is concluded that periodic ice moving avoids the increased heat resistance that creates a decreased evaporating temperature. Due to a better heat exchanger ability caused by the larger surface of sheet ice, steady and low chilled water temperature was directly extracted from an ice storage tank. The longitudinal and axial fin-added coils improved the COP of the refrigerating unit and ice-packing factors
Conformal and non-conformal hyperloop deformations of the 1/2 BPS circle
We construct new large classes of BPS Wilson hyperloops in three-dimensional N=4 quiver Chern-Simons-matter theory on S3. The main strategy is to start with the 1/2 BPS Wilson loop of this theory, choose any linear combination of the supercharges it preserves, and look for deformations built out of the matter fields that still preserve that supercharge. This is a powerful generalization of a recently developed approach based on deformations of 1/4 and 1/8 BPS bosonic loops, which itself was far more effective at discovering new operators than older methods relying on complicated ansatze. We discover many new moduli spaces of BPS hyperloops preserving varied numbers of supersymmetries and varied subsets of the symmetries of the 1/2 BPS operator. In particular, we find new bosonic operators preserving 2 or 3 supercharges as well as new families of loops that do not share supercharges with any bosonic loops, including subclasses of both 1/8 and 1/4 BPS loops that are conformal
Online Dynamics Learning for Predictive Control with an Application to Aerial Robots
In this work, we consider the task of improving the accuracy of dynamic
models for model predictive control (MPC) in an online setting. Even though
prediction models can be learned and applied to model-based controllers, these
models are often learned offline. In this offline setting, training data is
first collected and a prediction model is learned through an elaborated
training procedure. After the model is trained to a desired accuracy, it is
then deployed in a model predictive controller. However, since the model is
learned offline, it does not adapt to disturbances or model errors observed
during deployment. To improve the adaptiveness of the model and the controller,
we propose an online dynamics learning framework that continually improves the
accuracy of the dynamic model during deployment. We adopt knowledge-based
neural ordinary differential equations (KNODE) as the dynamic models, and use
techniques inspired by transfer learning to continually improve the model
accuracy. We demonstrate the efficacy of our framework with a quadrotor robot,
and verify the framework in both simulations and physical experiments. Results
show that the proposed approach is able to account for disturbances that are
possibly time-varying, while maintaining good trajectory tracking performance.Comment: 8 pages, 4 figure
Open-closed field algebras
We introduce the notions of open-closed field algebra and open-closed field
algebra over a vertex operator algebra V. In the case that V satisfies certain
finiteness and reductivity conditions, we show that an open-closed field
algebra over V canonically gives an algebra over a \C-extension of the
Swiss-cheese partial operad. We also give a tensor categorical formulation and
categorical constructions of open-closed field algebras over V.Comment: 55 pages, largely revised, an old subsection is deleted, a few
references are adde
Isolation and Cloning of Genes Induced by Sodium Carbonate in \u3cem\u3eLeymus chinensis\u3c/em\u3e
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