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Novel boron 2-(2′-pyridyl)imidazole (BOPIM) complexes T1, T2 and T3 with different substituents (including bromo, tert-butyl and methoxyl) on the benzene ring of BOPIM dyes have been designed and synthesized, and their optical properties in both solution and the solid state were investigated and compared. The three compounds exhibited typical intramolecular charge transfer (ICT) characteristics. Solvent-dependent UV-vis absorption, fluorescence emission spectra and quantum chemical calculation indicated a molecular push-pull electronic structure. Their ICT degrees increased with the sequence of T1

Selection by progressive refinement allows the accurate acquisition of targets with small visual sizes while keeping the required precision of the task low. Using the eyes as a means to perform 3D selections is naturally hindered by the low accuracy of eye movements. To account for this low accuracy, we propose to use the concept of progressive refinement to allow accurate 3D selection. We designed a novel eye tracking selection technique with progressive refinement–Eye-controlled Sphere-casting refined by QUAD-menu (EyeSQUAD). We propose an approximation method to stabilize the calculated point-of-regard and a space partitioning method to improve computation. We evaluated the performance of EyeSQUAD in comparison to two previous selection techniques–ray-casting and SQUAD–under different target size and distractor density conditions. Results show that EyeSQUAD outperforms previous eye tracking-based selection techniques, is more accurate and can achieve similar selection speed as ray-casting, and is less accurate and slower than SQUAD. We discuss implications of designing eye tracking-based progressive refinement interaction techniques and provide a potential solution for multimodal user interfaces with eye tracking.

Real-world, long-running Internet of Things (IoT) requires intense user-node interaction in the deployment, network operation, and maintenance stages. The rapidly increasing number of IoT nodes urges a new user-friendly interface to reduce the interaction complexity. This paper presents INSIGHT, an AR-enabled user interface for IoT nodes allowing the users to directly grasp perceptual node information from the surrounding videos shot by mobile AR devices such as smart glasses and phones. INSIGHT incorporates camera, magnetic, and IMU sensor data from an AR device to detect, locate, and recognize IoT nodes markerlessly. An intuitive user interface will then be overlaid on each recognized node for fetching/feeding information from/to the node. We have validated the performance of INSIGHT in terms of localization accuracy and the capability to distinguish nearby nodes. The results show that INSIGHT works well even in densely deployed networks.

New triphenylacrylonitrile derivative (DPPA) with triphenylamine moiety as electron donor group has been synthesized. Its emission wavelengths were strongly affected by solvent polarity, indicating intramolecular charge transfer (ICT) transitions. It was found that DPPA was almost non-emissive in tetrahydrofuran (THF), and the emission could be intensified obviously when a great amount of H2O was added, illustrating aggregation induced emission property. It is interesting that the pristine crystal of DPPA emitted green light, and the ground made its emitting color to change into orange, which could be recovered under fumed with dichloromethane (DCM) vapor. The piezofluorochromic behavior might be switched reversibly under the stimulus of external force because of crystalline-amorphous phase transformation, which could be confirmed from the results of PXRD patterns and DSC curves in different solid states. This work might open a new strategy to provide a broad perspective for the development of AIE PFC materials.

For the superiority of graphene quantum dots (GQDs) in bioimaging and drug delivery carrier, GQDs bring new opportunities for theranostics of diseases. In this study, GQDs were successfully prepared and labeled with 131I. The in vitro properties, biodistribution and SPECT imaging of 131I-GQDs were investigated. The uptake of 131I-GQDs at tumor sites can be clearly observed via SPECT imaging and T/B and T/M ratios increase with increasing time, which can contribute to enhanced permeability and retention (EPR) effect.

Our aim in this paper is to consider the integer part of a nonlinear form representing primes. We establish that if \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\lambda_{1},\lambda _{2},\ldots,\lambda_{8}$\end{document}λ1,λ2,…,λ8 are positive real numbers, at least one of the ratios \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\lambda_{i}/\lambda_{j}$\end{document}λi/λj (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$1\leq i< j\leq 8$\end{document}1≤i

The temperature effect on rock physical properties, including permeability, is still topical, since the available findings are quite contradictory. In the current study of temperature effect on rock permeability, the experiments have been conducted on eight rock samples of different permeability (4) and lithology (4). The results obtained strongly indicate that the temperature effect depends on the initial permeability of core samples: for low-permeability (LP) or higher-permeability (HP) rocks, the temperature-permeability dependence exhibits a negative nonlinear correlation. When the temperature increases from 20 °C to 100 °C, the permeability of LP rocks decreases by 24–70%. However, in ultra-LP rocks, a positive nonlinear correlation has been revealed between temperature and permeability: when the temperature was increased from 100 to 800 °C, the permeability of ultra-LP rocks exhibited a gradual increase within the initial range from 200 °C to 400 °C, and a sharp rise, while in the medium range from 400 to 600 °C the lithology threshold value was reached, the thermal-induced tensile stress in the rock exceeded its yield stress, which resulted in a sharp increase of permeability in the final temperature range from 600 to 800 °C. Based on the experimental data obtained in this study, a theoretical model is proposed, which implies a positive correlation between rock permeability, pressure, and temperature.

The authors report on a chromogenic system based MnO2 nanosheet and the chomgenic substrate 3,3′,5,5′-tetramethylbenzidine (TMB). The MnO2 nanosheet can oxidize TMB in acidic environment to form a yellow solution with an absorption peak at 450 nm. The process does not require the presence of an enzyme or H2O2. However, on addition of ferrous ion to the chromogenic system, the MnO2 nanosheet is decomposed via the redox reaction that occurs between Fe(II) and MnO2. As a result, the intensity of the absorption at 450 nm is reduced. This finding is exploited in a photometric method for determination of Fe(II) that shows high selectivity and a 0.3 μM detection limit (based on the 3σ/slope criterion). Fe(II) can also be detected visually in concentrations down to 100 μM. The method was applied to the determination of Fe(II) in spiked water samples and gave satisfactory recoveries.

High-frequency trading (HFT) has continuously evolved and dominated trading in the past decades. However, HFT trading marker prediction is a rarely investigated problem in Fintech literature. In this study, we first propose a novel manifold learning based HFT trading marker prediction model: M-SCAN to handle this challenge. Our study takes advantage of manifold embeddings of HFT data and seeks potential markers among the outliers in density-based clustering. We further propose HFT trading marker evaluation algorithms to validate the prediction effectiveness besides unveiling trading marker discovery via visualization. Our results demonstrate locally linear embedding (LLE) outperforms its peers in capturing trading markers in terms of accuracy and complexity for its local data structure keeping mechanism in embedding though different stocks may demonstrate their model preference under M-SCAN. Our studies also propose novel entropy and variance concentration ratios (VCR) to quantify HFT data and show that a high-entropy dataset is more likely to have better trading marker prediction than a low-entropy one. To the best of our knowledge, it is the first study in HFT trading marker prediction and will inspire coming studies in this area.

Two phenothiazine-based quinoxaline derivatives QPT1 and QPT2 have been rationally designed and synthesized. Optical analysis and theoretical chemical calculations illustrated that they showed typical intramolecular charge transfer (ICT) process from electron-rich phenothiazine unit to electron-withdrawing quinoxaline moiety. Interestingly, QPT1 exhibited the polymorphism feature and high-contrast mechanochromic luminescence. Two types of crystals were prepared by solvent evaporation method. A green needle-like crystal (G-form) and a yellow ribbon-like crystal (Y-form) were yielded from dichloromethane/petroleum ether and THF solution, respectively. The emission peaks of G-form and Y-form in pristine powders appeared at 501 nm and 549 nm, and red-shifted to 570 nm and 594 nm in ground powders, respectively, giving the emission spectral shifts of 69 nm for G-form and 45 nm for Y-form. Besides, QPT2 exhibited moreover autonomously self-recovering mechanochromic luminescence. X-ray diffraction measurements confirmed that the reversible phase transition between the crystalline and amorphous states has been proposed as the MFC mechanism. Moreover, QPT1 and QPT2 also showed stable acidofluorochromic characteristics. The solution and film of QPT1 and QPT2 achieved a fast response to TFA with high sensitivity and low detection limit. The multiple stimuli responsive performances of QPT1 and QPT2 make them potential candidates for smart materials.