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71.
Lacking rapid and reliable pathogen diagnostic platforms, inadequate or delayed antimicrobial therapy could be made, which greatly threatens human life and accelerates the emergence of antibiotic‐resistant pathogens. In this contribution, a series of simple and reliable sensor arrays based on tetraphenylethylene (TPE) derivatives are successfully developed for detection and discrimination of pathogens. Each sensor array consists of three TPE‐based aggregation‐induced emission luminogens (AIEgens) that bear cationic ammonium group and different hydrophobic substitutions, providing tunable logP (n‐octanol/water partition coefficient) values to enable the different multivalent interactions with pathogens. On the basis of the distinctive fluorescence response produced by the diverse interaction of AIEgens with pathogens, these sensor arrays can identify different kinds of pathogens, even normal and drug‐resistant bacteria, with nearly 100% accuracy. Furthermore, blends of pathogens can also be identified accurately. The sensor arrays exhibit rapid response (about 0.5 h), high‐throughput, and easy‐to‐operate without washing steps.  相似文献   
72.
Supramolecular approaches have opened up vast possibilities to construct versatile materials, especially those with stimuli-responsiveness and integrated functionalities of multi-modal diagnosis and synergistic therapeutics. In this study, a hybrid theranostic nanosystem named TTPY-Py⊂CP5@AuNR is constructed via facile host–guest interactions, where TTPY-Py is a photosensitizer with aggregation-induced emission and CP5@AuNR represents the carboxylatopillar[5]arene (CP5)-modified Au nanorods. TTPY-Py⊂CP5@AuNR integrates the respective advantages of TTPY-Py and CP5@AuNR such as the high performance of reactive oxygen species generation and photothermal conversion, and meanwhile shows fluorescence responses to both temperature and pH stimuli. The successful modification of CP5 macrocycles on AuNRs surfaces can eliminate the cytotoxicity of AuNRs and enable them to serve as the nanocarrier of TTPY-Py for further theranostic applications. Significantly, in vitro and in vivo evaluations demonstrate that this supramolecular nanotheranostic system possesses multiple modalities including intensive fluorescence imaging (FLI), photoacoustic imaging (PAI), efficient photodynamic therapy (PDT), and photothermal therapy (PTT), indicating its great potential for FLI-PAI imaging-guided synergistic PDT-PTT therapy. Moreover, TTPY-Py can be released upon activation by the acidic environment of lysosomes and then specifically light up mitochondria. This study demonstrates a new strategy for the design of versatile nanotheranostics for accurate tumor imaging and cancer therapies.  相似文献   
73.
温度是影响半导体激光器(LD)寿命和输出特性的重要因素之一。为保证LD输出稳定的激光模式和功率,采用以ADC和DAC集成的微处理器芯片C8051F350和具有双极性输出电流的TEC驱动芯片MAX1968为控制核心,以积分分离和变速积分增量式相结合的数字PID算法为运算程序的自动温度控制系统(ATC)控制TEC驱动电流的方向和大小,实现对LD的加热或制冷,使其工作在恒定温度。实验证明,应用该系统,LD在0℃~40℃环境温度范围内能很快稳定在设定温度,且其不确定度为±0.03℃。  相似文献   
74.
Dataflow modeling offers a myriad of tools for designing and optimizing signal processing systems. A designer is able to take advantage of dataflow properties to effectively tune the system in connection with functionality and different performance metrics. However, a disparity in the specification of dataflow properties and the final implementation can lead to incorrect behavior that is difficult to detect. This motivates the problem of ensuring consistency between dataflow properties that are declared or otherwise assumed as part of dataflow-based application models, and the dataflow behavior that is exhibited by implementations that are derived from the models. In this paper, we address this problem by introducing a novel dataflow validation framework (DVF) that is able to identify disparities between an application’s formal dataflow representation and its implementation. DVF works by instrumenting the implementation of an application and monitoring the instrumentation data as the application executes. This monitoring process is streamlined so that DVF achieves validation without major overhead. We demonstrate the utility of our DVF through design and implementation case studies involving an automatic speech recognition application, a JPEG encoder, and an acoustic tracking application.  相似文献   
75.
Techniques for modeling and simulating channel conditions play an essential role in understanding network protocol and application behavior. In [11], we demonstrated that inaccurate modeling using a traditional analytical model yielded suboptimal error control protocol parameters choices. In this paper, we demonstrate that time-varying effects on wireless channels result in wireless traces which exhibit non-stationary behavior over small window sizes. We then present an algorithm that extracts stationary components from a collected trace in order to provide analytical channel models that, relative to traditional approaches, more accurately represent characteristics such as burstiness, statistical distribution of errors, and packet loss processes. Our algorithm also generates artificial traces with the same statistical characteristics as actual collected network traces. For validation, we develop a channel model for the circuit-switched data service in GSM and show that it: (1) more closely approximates GSM channel characteristics than traditional Markov models and (2) generates artificial traces that closely match collected traces' statistics. Using these traces in a simulator environment enables future protocol and application testing under different controlled and repeatable conditions.  相似文献   
76.
In this paper, we are interested in the problem of Blind Source Separation using a Second-order Statistics (SOS) method in order to separate autocorrelated and mutually independent sources mixed according to a bilinear (BL) model. In this context, we propose a new approach called Bilinear Second-order Blind Source Separation, which is an extension of linear SOS methods, devoted to separate sources present in BL mixtures. These sources, called extended sources, include the actual sources and their products. We first study the statistical properties of the different extended sources, in order to verify the assumption of identifiability when the actual sources are zero-mean and when they are not. Then, we present the different steps performed in order to estimate these actual centred sources and to extract the actual mixing parameters. The obtained results using artificial mixtures of synthetic and real sources confirm the effectiveness of the new proposed approach.  相似文献   
77.
Graphene-based materials have attracted significant attention in many technological fields, but scaling up graphene-based technologies still faces substantial challenges. High-throughput top-down methods generally require hazardous, toxic, and high-boiling-point solvents. Here, an efficient and inexpensive strategy is proposed to produce graphene dispersions by liquid-phase exfoliation (LPE) through a combination of shear-mixing (SM) and tip sonication (TS) techniques, yielding highly concentrated graphene inks compatible with spray coating. The quality of graphene flakes (e.g., lateral size and thickness) and their concentration in the dispersions are compared using different spectroscopic and microscopy techniques. Several approaches (individual SM and TS, and their combination) are tested in three solvents (N-methyl-2-pyrrolidone, dimethylformamide, and cyrene). Interestingly, the combination of SM and TS in cyrene yields high-quality graphene dispersions, overcoming the environmental issues linked to the other two solvents. Starting from the cyrene dispersion, a graphene-based ink is prepared to spray-coat flexible electrodes and assemble a touch screen prototype. The electrodes feature a low sheet resistance (290 Ω □−1) and high optical transmittance (78%), which provide the prototype with a high signal-to-noise ratio (14 dB) and multi-touch functionality (up to four simultaneous touches). These results illustrate a potential pathway toward the integration of LPE-graphene in commercial flexible electronics.  相似文献   
78.
Aggregation-induced emission (AIE) and hybridized local and charge-transfer (HLCT) materials are two kinds of promising electroluminescence systems for the fabrication of high-efficiency organic light-emitting diodes (OLEDs) by harnessing “hot excitons” at the high-lying triplet exciton states (Tn, n ≥ 2). Nonetheless, the efficiency of the resulting OLEDs did not meet expectations due to the possible loss of Tn→Tn−1. Herein, experimental results and theoretical calculations demonstrate the “hot exciton” process between the high-lying triplet state T3 and the lowest excited singlet state S1 in an AIE material 4⁗-(diphenylamino)-2″,5″-diphenyl-[1,1″:4′,1″:4″,1′″:4′″,1⁗-quinquephenyl]-4-carbonitrile (TPB-PAPC) and it is found that the Förster resonance energy transfer (FRET) between two molecules can facilitate the “hot exciton” process and inhibit the T3→T2 loss by doping a blue fluorescent emitter in TPB-PAPC. Finally, the doped TPB-PAPC blue OLEDs achieve a maximum external quantum efficiency (EQEmax) of 9.0% with a small efficiency roll-off. Furthermore, doping the blue fluorescent emitter in a HLCT material 2-(4-(10-(3-(9H-carbazol-9-yl)phenyl)anthracen-9-yl)phenyl)-1-phenyl-1H-phenanthro[9,10-d] imidazole (PAC) is used as the emission layer, and the resulting blue OLEDs exhibit an EQEmax of 17.4%, realizing the efficiency breakthrough of blue fluorescence OLEDs. This work establishes a physical insight in the design of high-performance “hot exciton” molecules and the fabrication of high-performance blue fluorescence OLEDs.  相似文献   
79.
地震资料处理是典型的高性能计算,随着采集数据量越来越大,对计算机资源的快速调度和配置提出了要求。为达到高效管理的目的,需要从技术选择、生产实际情况、业务特点等方面综合考虑,建立智能化的资源管理调度平台,使资源的提供与回收等管理具备云计算特征。  相似文献   
80.
郑本军 《光通信研究》1999,(4):17-19,37
用户电路板具有数字/模拟信号混合,电源种类多,地线种类多,元器件多密度大等特点,因而会带来一 系列干扰问题,正确合理的布局布线,对抑制其干扰起着重要作用。本文通过几个典型实例,分析其干扰现象和干扰原因,并给出了抑制其干扰的有效措施。最后提出了用户电路板中印制板电源,地线布线设计时应注意的问题。  相似文献   
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