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71.
针对5G超密集异构蜂窝网络中人与人(H2H)和机器到机器(M2M)共存场景下有服务质量(QoS)保障和负载均衡的上行用户分配问题,该文提出一种基于匹配理论的用户分配算法.该算法在用户分配过程中同时考虑不同类型节点的接入控制策略,在最大化网络能效的同时,实现节点QoS保障.仿真结果表明,与其他算法相比,该算法不仅能够在能效、负载均衡以及QoS保障方面获得更好的性能,并且能获得与穷举法相近的性能.此外,所提算法的收敛速度很快且不受节点和基站数目变化的影响,适合解决H2H和M2M共存场景中的用户分配问题.  相似文献   
72.
Based on the quadratic exponential method, this paper constructs two types of generators over finite field Fq, the digital quadratic exponential generator and quadratic exponential pseudorandom vector generator. We investigate the distribution of the sequence generated by the generators, and present results about their one dimensional discrepancy. The proofs are based on the estimate of certain character sum over Fq. Ift is the least period of the sequence and t≥q^1/2+2c, then the bound of the discrepancy is O(t^-1/4q^1/8+τ logq) for any ε 〉 0. It shows that the sequence is asymptotically uniformly distributed.  相似文献   
73.
简要介绍了光子产业的发展历史、现状、特点和趋势,初步研究了光子产业的发展模式和领域,对确立光子产业在西部发展中的战略地位有较高的参考价值。  相似文献   
74.
The shortage of freshwater resources has become a major obstacle threatening human development, and directly utilizing solar energy by solar evaporators is emerging as a promising method to produce freshwater from the seawater. Compared to many synthetic polymer-based evaporators, cellulose-based evaporators are expected to offer more interesting features benefiting from the renewable feature and abundant reserves of cellulose-contained naturally occurring materials. First, according to the different fabrication methods, cellulose-based solar evaporators can be divided into two types, i.e., top-down utilization (wood-based) and bottom-up assembled (cellulose composite-based), respectively. The different fabrication schemes also bring their own unique advantages, such as the bimodal porous structure of wood-based evaporators and the artificial interconnection microporous network of cellulose composite-based evaporators. Subsequently, this review further summarizes the most recent advances and highlights of those cellulose-based solar evaporators, by focusing on their structural regulation strategies (e.g., drilled channel array, asymmetric wettability structure, delignification, 2D waterway, etc.) and evaporation performance improvements (e.g., salt resistance, high evaporation rate, etc.). Finally, the challenges in this field and potential solutions are also discussed, which are anticipated to provide new opportunities toward the future development of cellulose and other kinds of biomass-based evaporators.  相似文献   
75.
随着使用电脑作为信息来源的与日俱增,触摸屏以其易于使用、坚固耐用、反应速度快、节省空间、易于交流等优点,并作为一种最为友善的人机接口在平板电脑上的应用也会越来越普及.针对上述实际状况,该文介绍了平板电脑触摸屏性能试验的技术依据,试验方法和程序.  相似文献   
76.
HP4191A射频阻抗分析仪的测量原理是测量阻抗的反射系数,他具有自动校准功能,根据3个参考值的校准值自动修正反射系数的误差。首先介绍他的主要性能特点、测量原理、3个参考阻抗件的原理结构和标准值,然后通过公式推导重点介绍他的误差修正方法。  相似文献   
77.
本文针对应用广泛的通用变频器,提出了在变频器选型和外围配置中需要注意的一些问题。  相似文献   
78.
The detection of ultraviolet (UV) radiation with effective performance and robust stability is essential to practical applications. Metal halide single-crystal perovskites (ABX3) are promising next-generation materials for UV detection. The device performance of all-inorganic CsPbCl3 photodetectors (PDs) is still limited by inner imperfection of crystals grown in solution. Here wafer-scale single-crystal CsPbCl3 thin films are successfully grown by vapor-phase epitaxy method, and the as-constructed PDs under UV light illumination exhibit an ultralow dark current of 7.18 pA, ultrahigh ON/OFF ratio of ≈5.22 × 105, competitive responsivity of 32.8 A W−1, external quantum efficiency of 10867% and specific detectivity of 4.22 × 1012 Jones. More importantly, they feature superb long-term stability toward moisture and oxygen within twenty-one months, good temperature tolerances at low and high temperatures. The ability of the photodetector arrays for excellent UV light imaging is further demonstrated.  相似文献   
79.
该系统在硬件上以大规模复杂可编程逻辑器件(FPGA)及微处理器(8051)为核心,采用模块化流水线处理结构,实现目标图像的实时跟踪.在系统软件上使用一种高效的快速相关算法MAD,建立相关跟踪置信度评估、模板自适应更换、目标丢失判断、抗干扰准则和再捕获等准则,有效地提高了目标跟踪的稳定性和抗干扰能力.  相似文献   
80.
A supermolecular photosensitizer with excellent anticancer behavior when used for photodynamic therapy (PDT) is fabricated by the incorporation of zinc phthalocyanines (ZnPc) into the gallery of a layered double hydroxide (LDH). The composite material possesses uniform particle size (hydrodynamic diameter ~120 nm), and the host–guest and guest–guest interactions result in a high dispersion of ZnPc in a monomeric state in the interlayer region of the LDH matrix, with high singlet oxygen production efficiency. In vitro tests performed with HepG2 cells reveal a satisfactory PDT effectiveness of the ZnPc(1.5%)/LDH composite photosensitizer: a cellular damage as high as 85.7% is achieved with a rather low dosage of ZnPc (10 μg/mL). An extraordinarily high specific efficacy is demonstrated (31.59 μg?1 (J/cm2)?1), which is over 185.5% enhancement compared with the previously reported photosensitizers under similar test conditions. Furthermore, an in vivo study of the ZnPc(1.5%)/LDH demonstrates excellent PDT performance with an ultra‐low dose (0.3 mg/kg) and a low optical fluence rate (54 J/cm2). In addition, the ZnPc/LDH photosensitizer displays high stability, good biocompatibility, and low cytotoxicity, which would guarantee its practical application. Therefore, this work provides a facile approach for design and fabrication of inorganic–organic supermolecular materials with greatly enhanced anticancer behavior.  相似文献   
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