Novel NIR-II organic fluorophores were designed and synthesized using an AIE and highly twisted donor–acceptor distortion strategy for bio-imaging beyond 1550 nm.
A new multispectral imaging spectrometer capable of simultaneously recording spectral images in the visible and near-infrared has been developed. In this instrument, an acoustooptic tunable filter is used to diffract an unpolarized incident light into two diffracted beams with orthogonal polarization; one of them is detected by a silicon camera for the visible region while the other beam is detected in the near-infrared region (from 1 to 1.7 microns) with a NIR camera. The imaging spectrometer is sensitive, inexpensive, and field deployable because it is based on the recently available InGaAs focal plane arrays camera, which is low cost and can be sensitively operated at room temperature. Preliminary applications of the imaging spectrometer include measurements of the visible and NIR absorption spectra of ink used to print U.S. currency. Such results may help to characterize samples as well as to control and to ensure the quality of the samples during the production processes. More important are the results obtained on ethylene/vinyl acetate copolymers. The NIR spectral images obtained clearly indicate that these copolymers exhibit a high degree of chemical inhomogeneity. Because of the possibility of inhomogeneity, it is very important that the homogeneity of polymers or copolymers be thoroughly understood before the NIR methods, especially those based on NIR spectrometers equipped with a single-element detector, are used for measurements.
We describe a spin logic device with controllable magnetization switching of perpendicularly magnetized ferromagnet / heavy metal structures on a ferroelectric (1-x)[Pb(Mg1/3Nb2/3)O3]-x[PbTiO3] (PMN-PT) substrate using current-induced spin-orbit torque. The devices were operated without an external magnetic field and controlled by voltages as low as 10 V applied across the PMN-PT substrate, which is much lower compared to previous reports (500 V). The deterministic switching with smaller voltage was realized from the virgin state of the PMN-PT. Ferroelectric simulation shows the unsaturated minor loop exhibits obvious asymmetries in the polarizations. Larger polarization can be induced from the initial ferroelectric state, while it is difficult for opposite polarization. The XNOR, AND, NAND and NOT logic functions were demonstrated by the deterministic magnetization switching from the interaction between the spin-orbit torque and electric field at the PMN-PT/Pt interface. The nonvolatile spin logic scheme in this work is simple, scalable, programmable, which are favorable in the logic-in-memory design with low energy consumption.
We propose an application of spectroscopic ellipsometry pertinent to the characterization of nanostructure inclination of oblique thin films. This technique is employed ex situ in the measurement of silicon thin films fabricated at oblique incidence and modeled as aggregate microstructures formed from amorphous silicon, silicon oxide, and void in the effective medium model. The technique may also be utilized in situ as a powerful probe for the characterization of oblique thin films during their fabrication and processing.
Accurate and dynamic visualization of vascular diseases can contribute to restraining the further deterioration of diseases in a timely manner. However, it is still unable to precisely determine whether and to what extent blood vessels or brain tissues are damaged. Here we report novel BBTD-based NIR-II fluorophores HY1-HY4 with highly twisted structures (55 o at the S 0 state), extremely strong aggregation-induced emission (AIE) characteristics (I/I 0 > 13), and remarkably high fluorescence QYs (up to 14.45%) in the NIR-II region (> 1000 nm) and ~ 0.27% in the NIR-IIb window (> 1500 nm) in aqueous solution. Using NIR-IIb AIE HY4 dots, high-resolution NIR-IIb fluorescence imaging of revascularization and thrombolysis, and real-time feedback of the therapeutic efficacy of Chinese medicine DXI on ischemic stroke, were achievedfor the first time. In addition, results showed that DXI conferred neuroprotection against cerebral ischemia injury mediated via the angiogenesis pathway. These attractive results provide a new perspective for designing ultra-bright NIR-IIb probes for the vascular-related phenomena, disease assessment, and precise intraoperative imageguided therapy with a deeper tissue penetration depth and higher resolution.
This paper is concerned with the problem of robust adaptive sliding mode control (RASMC) for discrete singular systems subject to randomly occurring mixed time-delays (ROMTDs) under uncertain occurrence probabilities. The mixed time delays are considered, which are comprised of both the discrete interval delays and infinite distributed delays. Meantime, two random variables obeying the Bernoulli distribution are utilised to depict the phenomena of randomly occurring discrete time-varying delay and distributed time-delay, in which the uncertain occurrence probabilities are modelled by the known scalars. An appropriate sliding surface function is firstly presented. Furthermore, some sufficient criteria via the free weighting matrices idea are obtained to ensure the admissibility of the resultant sliding motion by introducing new Lyapunov-Krasovskii functional. Subsequently, an RASMC law is synthesised to ensure the reachability criterion of pre-designed sliding surface, where an adaptive mechanism is introduced to estimate the related unknown bounds. Finally, the feasibility of the new RASMC strategy is illustrated by a numerical simulation.
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