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111.
112.
This paper proposes a Gaussian mixture model-based Bayesian
analysis for blind source separation of an underdetermined model that has more
sources than sensors. The proposed algorithm follows a hierarchical learning
procedure and alternative estimations for sources and the mixing matrix. The
independent sources are estimated from their posterior means, and the mixing
matrix is estimated by the maximum likelihood method. Because each source
is conditionally correlated with others in its Markov blanket, the
correlations between them are approximated by using linear response theory;
this is based on the factorized approximation to the sources' true
posteriors. In this framework, each source is modeled as a mixture of
Gaussians to fit its actual distribution. Given enough Gaussians, the
mixture model can learn any distribution. The algorithm provides a good
identification of the mixing system, and its flexibility speeds up
the convergence. The iterative learning for Gaussians leads to a parametric
density estimation for all hidden sources as well as their recovery in the
end. The major advantages of this algorithm are its flexibility and its fast
convergence. Simulations using synthetic data validate the effectiveness
of the algorithm. 相似文献
113.
114.
动态显示网络系统的拓扑图是网络管理系统的基本功能,目前常见的拓扑搜索算法大部分都是基于网络层的,不能对链路层的动态网络拓扑进行搜索且不能发现和管理虚拟网。提出一种利用SNMP协议、ICMP 协议和ARP协议三种协议相结合的网络拓扑搜索算法,发现ATM网络的链路层网络拓扑和提取ATM虚拟网的配置信息。最后,以哈工大通信所的某一子网(ATM虚拟局域网)为例,对此算法进行了验证。 相似文献
115.
Triboelectric nanogenerators (TENGs) have attracted great interests in the development of sustainable energies and intelligent society. However, a big challenge for TENGs in practical applications is the unavoidable external mechanical abrasion and/or contaminant adsorption on the triboelectric materials, which leads to the significant decrease of the durability of TENGs and is urgently needed to be addressed. There are already a series of interesting progresses on the topic of the TENGs’ durability. In this study, reviewing the durability of TENGs via both the advanced materials/structure designing and the novel surface/interface engineering is focused upon, which includes choosing basic TENG materials, improving composites performance, optimizing structures, and designing triboelectric surfaces and interfaces. To get a better understanding of the durability of TENGs in published studies, the quantifiable levels of service life are also summarized including operation cycles, time, friction coefficient, and wear loss of triboelectric materials, where the boosting mechanisms are also discussed and summarized. Finally, the challenges as well as key strategies toward high durable TENGs are presented. 相似文献
116.
Yanling Xiao Wei Deng Jiajing Hong Xiaobin Ren Xiujuan Zhang Jialin Shi Fangming Sheng Xiaohong Zhang Jiansheng Jie 《Advanced functional materials》2023,33(23):2213788
Application-oriented growth of patterned organic semiconductor (OSC) thin films with a single domain is a nonnegotiable requirement for the manufacturing of high-performance organic electronic devices. However, the prevalent selective-wetting patterning method remains a challenge in controlling the density of nucleation events in microscale spaces, resulting in thin films with high grain boundary density and no preferential orientation spherulites. Herein, a simple double-blade-coating printing technique using a combination of wetting-patterned substrates to produce an array of highly crystalline OSC thin films is developed. Specifically, the approach confines the OSC crystallization on a molecular-flat water surface in specific areas, enabling a significant reduction in the number of nuclei. Consequently, patterned 2,7-dioctyl[1]benzothieno[3,2-b] benzothiophene (C8-BTBT) thin films comprising single-crystal domains are achieved with an exceptionally high yield of 62.5%. The organic field-effect transistor array developed from such patterns of C8-BTBT single-crystalline films exhibits an excellent average mobility of 11.5 cm2 V−1 s−1 which is 12.5-fold higher compared to that of the reference sample fabricated via conventional single-blade coating. It is believed that this approach can be widely applied to other soluble organic materials, thereby opening up opportunities for fabricating multicomponent integrated electronics. 相似文献
117.
Yang Shi Jue Shi Yuan Sun Qiqi Liu Chun Zhang Changyu Shao Kang Yu Mingjie Ge Rui Mi Jingyi Gu Wenzhi Wu Weiying Lu Zhuo Chen Yong He Ruikang Tang Zhijian Xie 《Advanced functional materials》2023,33(40):2301099
An ideal craniofacial bone repair graft shall not only focus on the repair ability but also the regeneration of natural architecture with occlusal loads-related function restoration. However, such functional bone tissue engineering scaffold has rarely been reported. Herein, a hierarchical 3D graft is proposed for rebuilding craniofacial bone with both natural structure and healthy biofunction reconstruction. Inspired by the bone healing process, an organic–inorganic nanoink with ultrasmall calcium phosphate oligomers and bone morphogenetic protein-2 incorporated is developed for spatiotemporal guidance of new bone. Based on such homogeneous nanoink, a biomimetic graft, including a cortical layer containing Haversian system, and a cancellous layer featured with triply periodic minimum surface macrostructures, is fabricated via projection-based 3D printing method, and the layers are loaded with distinct concentrations of bioactive factors for regenerating new bone with gradient density. The graft exhibits excellent osteogenic and angiogenic potential in vitro, and accelerates revascularization and reconstructs neo-bone with original morphology in vivo. Benefiting from such natural architecture, loading force is widely transferred with reduced stress concentration around the inserted dental implant. Taken from native physiochemical and structural cues, this wstudy provides a novel strategy for functional tissue engineering through designing function-oriented biomaterials. 相似文献
118.
Shan Zhang Lina Wu Wenqiang Shi Junchang Qin Wei Feng Yu Chen Ruifang Zhang 《Advanced functional materials》2023,33(29):2302360
Photodynamic therapy (PDT) as a non-invasive strategy shows high promise in cancer treatment. However, owing to the hypoxic tumor microenvironment and light irradiation-mediated rapid electron–hole pair recombination, the therapeutic efficacy of PDT is dramatically discounted by limited reactive oxygen species (ROS) generation. Herein, a multifunctional theranostic nanoheterojunction is rationally developed, in which 2D niobium carbide (Nb2C) MXene is in situ grown with barium titanate (BTO) to generate a robust photo-pyroelectric catalyst, termed as BTO@Nb2C nanosheets, for enhanced ROS production, originating from the effective electron–hole pair separation induced by the pyroelectric effect. Under the second near-infrared (NIR-II) laser irradiation, Nb2C MXene core-mediated photonic hyperthermia regulates temperature variation around BTO shells facilitating the electron–hole spatial separation, which reacts with the surrounding O2 and H2O molecules to yield toxic ROS, achieving a synergetic effect by means of combinaterial photothermal therapy with pyrocatalytic therapy. Correspondingly, the engineered BTO@Nb2C composite nanosheets feature benign biocompatibility and high antitumor efficiency with the tumor-inhibition rate of 94.9% in vivo, which can be applied as an imaging-guided real-time non-invasive synergetic dual-mode therapeutic nanomedicine for efficient tumor nanotherapy. 相似文献
119.
Zhijie Bi Ruidong Shi Xiaoning Liu Kaiyue Liu Mengyang Jia Xiangxin Guo 《Advanced functional materials》2023,33(43):2307701
Garnet-type electrolytes demonstrate promising prospects in the field of solid-state lithium batteries owing to their superior ionic conductivity and high (electro)chemical stability toward Li metal, whereas the critical issue of Li dendrite growth and even infiltration throughout garnets limits their practical applications. Herein, a hybrid interlayer consisting of Li3Bi alloy embedded in antiperovskite-type Li3OCl matrix is in situ constructed at Li/Li6.75La3Zr1.75Ta0.25O12 interface by taking the conversion reaction of BiOCl with Li metal. The lithiophilic nature of such interlayer enables an intimate contact of garnet against Li metal, guaranteeing a dramatically reduced interfacial resistance of 27 Ω cm2. In addition, the inside electron-conducting Li3Bi nanoparticles homogenize the interfacial potential distribution, while the outside ion-conducting Li3OCl matrix with a bandgap of 5.06 eV blocks electron tunneling from Li bulk. Profiting from such synergistic effect, the resultant Li symmetric cell displays a high critical current density of 1.1 mA cm−2, along with an ultralong cycling life of 1000 h at 0.5 mA cm−2. Furthermore, the corresponding solid LiNi0.6Co0.2Mn0.2O2/Li cell delivers a high cycling stability for 150 times accompanied by a capacity retention of 82%. This study puts forward a potential solution for construction of functional layers at Li/garnet interfaces by making use of in situ conversion reaction. 相似文献
120.
针对火箭炮在射前准备阶段里只能进行两自由度的角运动,造成部分参数不可观的缺陷,在基于对火箭炮进行制导化改造的背景下,提出了在射前准备阶段加入横滚运动的标定方案以及相应的可观测度分析方法。首先建立了21 维误差模型;而后运用可观测度分析方法对误差参数的可观测度进行了分析,对三个阶段进行了比较,表明横滚运动可使多个参数变得可观,并且其他参数可观测度也大幅提升;最后,采用奇异值分解的方法对所提出的标定方案和可观测度分析方法进行仿真验证,结果表明:除x 轴陀螺刻度系数误差外,其余参数奇异值基本都大于1,与可观测度分析方法的结论一致,充分体现了横滚运动对误差参数估计的有效性以及可观测度分析方法的可行性。 相似文献