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971.
针对在提升高动态范围红外图像中潜在或弱小目标细节的同时,还需兼顾噪声抑制、对比度增强的问题,提出了一种基于引导滤波图像分层的动态范围及细节增强算法。对背景层采用平台直方图均衡算法进行压缩,对细节层先采用中值滤波进行去噪,再采用非线性映射对细节中潜在的弱小目标细节进行增强,最后按照一定权重合并得到细节增强后的图像。综合主、客观实验结果,相对于映射类、直方图均衡、双边滤波分层增强等算法,该算法能够在动态范围压缩的过程中提高红外图像目标场景的对比度,突显其纹理特征,取得良好的细节增强效果。 相似文献
972.
设计了一种集成双半桥和四功率开关的驱动芯片。采用双路对称设计,每一路可单独控制使能、自举和驱动。芯片内部采用高精度的基准源以及LDO电路,同时具有欠压死锁、过压保护和过温保护功能。死区控制可避免上下功率管直通大电流,自举设计可使上功率管的开启电压达到5 V,降低了功率管自身的损耗,使功率管输出达到11.90 V。采用TSMC 0.18μm BCD工艺进行流片。测试结果表明,输出的方波信号幅度为11.96 V/11.95 V,死区时间为60 ns/80 ns,静态功耗低至478μA。 相似文献
973.
集成电路(ICs)面临着硬件木马(HTs)造成的严峻威胁。传统的旁路检测手段中黄金模型不易获得,且隐秘的木马可以利用固硬件联合操作将恶意行为隐藏在常规的芯片运行中,更难以检测。针对这种情况,该文提出利用机器学习支持向量机(SVM)算法从系统操作层次对旁路分析检测方法进行改进。使用现场可编程门阵列(FPGA)验证的实验结果表明,存在黄金模型时,有监督SVM可得到86.8%的训练及测试综合的平均检测准确率,进一步采用分组和归一化去离群点方法可将检测率提升4%。若黄金模型无法获得,则可使用半监督SVM方法进行检测,平均检测率为52.9%~79.5%。与现有同类方法相比,验证了SVM算法在指令级木马检测中的有效性,明确了分类学习条件与检测性能的关系。 相似文献
974.
Dengfeng Li Junfeng Gao Peng Cheng Jia He Yan Yin Yanxiao Hu Lan Chen Yuan Cheng Jijun Zhao 《Advanced functional materials》2020,30(8)
The structures of boron clusters, such as flat clusters and fullerenes, resemble those of carbon. Various two‐dimensional (2D) borophenes have been proposed since the production of graphene. The recent successful fabrication of borophene sheets has prompted extensive researches, and some unique properties are revealed. In this review, the recent theoretical and experimental progress on the structure, growth, and electronic and thermal transport properties of borophene sheets is summarized. The history of prediction of boron sheet structures is introduced. Existing with a mixture of triangle lattice and hexagonal lattice, the structures of boron sheets have peculiar characteristics of polymorphism and show significant dependence on the substrate. Due to the unique structure and complex B? B bonds, borophene sheets have many interesting electronic and thermal transport properties, such as strong nonlinear effect, strong thermal transport anisotropy, high thermal conductance in the ballistic transport and low thermal conductivity in the diffusive transport. The growth mechanism and synthesis of borophene sheets on different metal substrates are also presented. The successful prediction and synthesis will shed light on the exploration of new novel materials. Besides, the outstanding and peculiar properties of borophene make them tempting platform for exploring novel physical phenomena and extensive applications. 相似文献
975.
Pingli Qin Tong Wu Zhengchun Wang Lan Xiao Liang Ma Feihong Ye Lun Xiong Xiangbai Chen Haixia Li Xueli Yu Guojia Fang 《Advanced functional materials》2020,30(12)
The plasmonic characteristic of core–shell nanomaterials can effectively improve exciton‐generation/dissociation and carrier‐transfer/collection. In this work, a new strategy based on core–shell Au@CdS nanospheres is introduced to passivate perovskite grain boundaries (GBs) and the perovskite/hole transport layer interface via an antisolvent process. These core–shell Au@CdS nanoparticles can trigger heterogeneous nucleation of the perovskite precursor for high‐quality perovskite films through the formation of the intermediate Au@CdS–PbI2 adduct, which can lower the valence band maximum of the 2,2,7,7‐tetrakis(N,N‐di‐p‐methoxyphenyl‐amine)9,9‐spirobifluorene (Spiro‐OMeTAD) for a more favorable energy alignment with the perovskite material. With the help of the localized surface plasmon resonance effect of Au@CdS, holes can easily overcome the barrier at the perovskite/Spiro‐OMeTAD interface (or GBs) through the bridge of the intermediate Au@CdS–PbI2, avoiding the carrier accumulation, and suppress the carrier trap recombination at the Spiro‐OMeTAD/perovskite interface. Consequently, the Au@CdS‐based perovskite solar cell device achieves a high efficiency of over 21%, with excellent stability of ≈90% retention of initial power conversion efficiencies after 45 days storage in dry air. 相似文献
976.
Yong Xia Wei Chen Peng Zhang Sisi Liu Kang Wang Xiaokun Yang Haodong Tang Linyuan Lian Jungang He Xinxing Liu Guijie Liang Manlin Tan Liang Gao Huan Liu Haisheng Song Daoli Zhang Jianbo Gao Kai Wang Xinzheng Lan Xiuwen Zhang Peter Müller‐Buschbaum Jiang Tang Jianbing Zhang 《Advanced functional materials》2020,30(22)
Trap states in colloidal quantum dot (QD) solids significantly affect the performance of QD solar cells, because they limit the open‐circuit voltage and short circuit current. The {100} facets of PbS QDs are important origins of trap states due to their weak or missing passivation. However, previous investigations focused on synthesis, ligand exchange, or passivation approaches and ignored the control of {100} facets for a given dot size. Herein, trap states are suppressed from the source via facet control of PbS QDs. The {100} facets of ≈3 nm PbS QDs are minimized by tuning the balance between the growth kinetics and thermodynamics in the synthesis. The PbS QDs synthesized at a relatively low temperature with a high oversaturation follow a kinetics‐dominated growth, producing nearly octahedral nanoparticles terminated mostly by {111} facets. In contrast, the PbS QDs synthesized at a relatively high temperature follow a thermodynamics‐dominated growth. Thus, a spherical shape is preferred, producing truncated octahedral nanoparticles with more {100} facets. Compared to PbS QDs from thermodynamics‐dominated growth, the PbS QDs with less {100} facets show fewer trap states in the QD solids, leading to a better photovoltaic device performance with a power conversion efficiency of 11.5%. 相似文献
977.
Jianqiang Qin Linkai Lan Shanshan Chen Feinan Huang Huanrong Shi Wenjie Chen Haibo Xia Kuan Sun Changduk Yang 《Advanced functional materials》2020,30(36)
Flexible and stretchable organic solar cells (OSCs) have attracted enormous attention due to their potential applications in wearable and portable devices. To achieve flexibility and stretchability, many efforts have been made with regard to mechanically robust electrodes, interface layers, and photoactive semiconductors. This has greatly improved the performance of the devices. State‐of‐the‐art flexible and stretchable OSCs have achieved a power conversion efficiency of 15.21% (16.55% for tandem flexible devices) and 13%, respectively. Here, the recent progress of flexible and stretchable OSCs in terms of their components and processing methods are summarized and discussed. The future challenges and perspectives for flexible and stretchable OSCs are also presented. 相似文献
978.
979.
数据中心网络中同时存在截止时间流(deadline flow)和非截止时间流(non-deadline flow),为降低非截止时间流的平均完成时间(Average Flow Complete Time,AFCT)同时维持低截止时间错失率(Deadline Miss Rate,DMR),本文提出了一种基于松弛时间与累计发送量的混合流调度机制(Slack Time and Accumulation based Mix-flow Scheduling,STAM).首先通过引入松弛时间的概念,衡量截止时间流对非截止时间流在传输时延上的宽容度;然后根据松弛时间,通过使截止时间流尽可能接近其规定截止时间完成,降低非截止时间流的完成时间;最后,利用最小累计发送量优先策略进一步降低非截止时间流的平均完成时间.仿真结果表明,该机制能有效降低非截止时间流的平均完成时间,同时保证较低的截止时间错失率. 相似文献
980.