Ethereum smart contracts are an innovation built on top of the blockchain technology, which provides a platform for automatically executing contracts in an anonymous, distributed, and trusted way. The problem is magni...
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Establishing and approaching the fundamental limit of orbital-angular-momentum (OAM) multiplexing are necessary and increasingly urgent for current multiple-input multiple-output research. In this work, we elaborate t...
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Establishing and approaching the fundamental limit of orbital-angular-momentum (OAM) multiplexing are necessary and increasingly urgent for current multiple-input multiple-output research. In this work, we elaborate the fundamental limit in terms of independent scattering channels (or the degrees of freedom of scattered fields) through angular-spectral analysis, in conjunction with a rigorous Green’s function method. The scattering-channel limit is universal for arbitrary spatial-mode multiplexing, which is launched by a planar electromagnetic device, such as antenna, metasurface, etc., with a predefined physical size. As a proof of concept, we demonstrate both theoretically and experimentally the limit by a phase-only metasurface hologram that transforms orthogonal OAM modes to plane-wave modes scattered at critically separated angular-spectral regions. Particularly, a minimax optimization algorithm is applied to suppress angular-spectrum aliasing, achieving good performances in both full-wave simulation and experimental measurement at microwave frequencies. This work offers a theoretical upper bound and corresponding approach route for engineering designs of OAM multiplexing.
As the core of GPU processing, the performance of Unified rendering array is directly affected by the shader driver. On the basis of research the structure of Unified rendering array processing, this paper proposes a ...
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The technical requirements of the control rod driving mechanism of the third generation PWR nuclear power plant are higher. The latch parts are designed with double tooth structure and welded on the wear-resistant sur...
The technical requirements of the control rod driving mechanism of the third generation PWR nuclear power plant are higher. The latch parts are designed with double tooth structure and welded on the wear-resistant surface by cobalt-based alloy surfacing. According to the structural characteristics and manufacturing process difficulties, a special welding device is developed. According to the test and finite element simulation, the related process parameters are optimized. The trial production of the parts was completed, and the parts were tested by metallography, liquid permeation test, hardness test and thermal life test. The results show that the latch parts have high hardness and wear resistance, and meet the requirements of the driving mechanism operation life of the third generation PWR nuclear power plant.
In the current practice of multi-axis machining of freeform surfaces, the interface surface between the roughing and finishing process is simply an offset surface of the nominal surface. While there have already been ...
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In the current practice of multi-axis machining of freeform surfaces, the interface surface between the roughing and finishing process is simply an offset surface of the nominal surface. While there have already been attempts at minimizing the machining time by considering the kinematic capacities of the machine tool and/or the physical constraints such as the cutting force, they all target independently at either the finishing or the roughing process alone and are based on the simple premise of an offset interface surface. Conceivably, since the total machining time should count that of both roughing and finishing process and both of them crucially depend on the interface surface, it is natural to ask if, under the same kinematic capacities and the same physical constraints, there is a nontrivial interface surface whose corresponding total machining time will be the minimum among all the possible（infinite） choices of interface surfaces, and this is the motivation behind the work of this paper. Specifically, with respect to the specific type of iso-planar milling for both roughing and finishing, we present a practical algorithm for determining such an optimal interface surface for an arbitrary freeform surface. While the algorithm is proposed for iso-planar milling, it can be easily adapted to other types of milling strategy such as contour milling. Both computer simulation and physical cutting experiments of the proposed method have convincingly demonstrated its advantages over the traditional simple offset method.
Combat search and rescue（CSAR） is a significant part of joint combat operation. The isolated personnel in hostile territory is of great value to both sides. For the sake of extremely high cost and massive consumptio...
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Combat search and rescue（CSAR） is a significant part of joint combat operation. The isolated personnel in hostile territory is of great value to both sides. For the sake of extremely high cost and massive consumption of time in military exercises, virtual reality is a preferred way to conduct the experiment. Mixed reality, known as MR, allows users to interact with the virtual objects, as well as the real objects. With MR devices, commanders get a better awareness of both virtual combat and real environment. Agent-based modelling is a relatively new approach to modelling systems composed of interacting objects. By analyzing the decision-making process of agents, codes are written to drive the simulation. Finally, the whole system is applied to HoloLens to provide a holographic demonstration.
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