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The free‐standing triboelectric nanogenerator (F‐S TENG) is demonstrated to be an efficient energy conversion device. However, limited by the inherent features of high‐voltage, low alternating current and high output impedance, TENGs suffer from inefficient energy utilization and difficulties in practical applications. Therefore, the efficient harvest of mechanical energy and optimization of output are currently critical issues for TENGs. Here, a strategy is proposed for optimizing the inherent features by coupling F‐S TENG to a capacitor auto‐conversion circuit (CAC). For the first time, a specific idea is proposed explicitly to reduce the output impedance by the management circuit. Eventually, a high current density of 32 A m−2 and a charge density of 1.75 mC m−2 are achieved, which is 8.78 times higher than previous works. The power density and energy density reach to 124 W m−2 and 252 mJ m−2 under 470 and 150 Ω respectively. Then, 5000 LEDs and two lamps rated at 220 V and 50 W are manually illuminated. The resulting pulse output is utilized as a trigger source for the thyristor, enabling DC contactless switching. This work provides a novel approach to realize high‐performance DC output of TENGs and effectively reduce external load impedance. [ABSTRACT FROM AUTHOR]

Nowadays, the development of direct current triboelectric nanogenerators (DC‐TENGs) is oriented toward practical applications such as real‐time efficient harvesting and supplying energy. This demands DC‐TENGs with a low loss factor, high energy utilization efficiency, device portability, and output stability. Herein, a constant‐voltage DC‐TENG (C‐DC‐TENG) with robust output performance, using the ternary dielectric triboelectrification effect is demonstrated, which gives a crest factor of 1.0082. The key to improving the output charge density is the number of subdivision units, a result of theoretical simulations and experiments of C‐DC‐TENG. The optimized C‐DC‐TENG achieves not only an output charge density of 3.902 mC m−2 per round but also an average power density of 8.77 W m−2 (3.508 W m−2 Hz−1), which both set a new record for the rotary DC‐TENG. Moreover, introducing soft polyester fur enables C‐DC‐TENG to maintain 100% output without wear after 800 000 cycles. This C‐DC‐TENG is faultlessly competent for powering 2784 LEDs in series and 25 parallel‐connected hygrothermographs continuously. This work provides a promising technique for large‐scale clean energy harvesting, accelerating the progress toward practical applications of DC‐TENG. [ABSTRACT FROM AUTHOR]

Fluorescent single crystals that respond to multiple external stimuli are of great interest in molecular machines, sensors, and displays. The integration of photo‐ or acid‐induced fluorescence enhancement and bending in one organic crystal, however, has not been reported yet. Herein, we report the interesting plastic photomechanical bending and switching on of the fluorescence of an azine crystal in a single‐crystal transformation, due to extended π‐conjugation and molecular slippage. Moreover, the fluorescent plastic bending driven by multiple volatile acid vapors was firstly observed, and attributed to the synergistic effect of push–pull electronic structure and hydrogen bonding. The single crystal also shows high elasticity under external force. In addition, reversible fluorescence switching can be triggered by grinding and solvent fuming, as well as by the adsorption and desorption of HCl vapor. The integration of plastic, elastic bending and switch‐on fluorescence into one single crystal provides a new strategy for next‐generation smart materials. [ABSTRACT FROM AUTHOR]

Fire warning and monitoring are very important for public safety and environmental protection. However, most of the proposed wind energy conversion devices based on triboelectric nanogenerator (TENG) only work for unidirectional and high‐speed wind and face the challenge of fatigue damage and even failure caused by cyclic stress. Moreover, TENG guided by the theory of fluid dynamics needs further exploration. Herein, a flow‐induced vibration effect based TENG (F‐TENG) for continuously capturing and monitoring multidirectional breeze (1.8–4.3 m s−1) is developed to build a self‐powered intelligent fire detection system (SIFDS). A dynamic model is proposed to study the intrinsic interaction between the electrical properties of F‐TENG and wind. Since the model optimized F‐TENG is more adaptable to wind characteristics, it delivers better performance and higher durability compared with previous studies. Relying on the dynamic model and combining the relationship between F‐TENG's electrical output and wind characteristics, a self‐powered visual wind sensing system is obtained. F‐TENG successfully drives some electronic devices to monitor environmental information, which is expected to provide data for SIFDS to reduce fire hazards. This study can provide an in‐depth understanding of the electromechanical conversion mechanism and large‐scale capture and utilization of breeze energy. [ABSTRACT FROM AUTHOR]

Various structures for triboelectric nanogenerators (TENGs) have been designed to generate clean, low‐frequency hydropower, and provide solutions for next‐generation sustainable power supplies, including the solid–liquid contact electrification mode and full‐packaged solid–solid contact electrification mode. However, most of them can only adapt to a single form of hydropower. Moreover, electrostatic shielding in water and corrosion of the triboelectric material in the solid–liquid mode are inevitable. In addition, the devices in the fully enclosed mode have the disadvantages of complexity, low cost‐effectiveness, and complex disassembly, which hinder its development and practicality. Herein, a non‐encapsulated polymorphous U‐shaped TENG for multiform hydropower harvesting with effective robustness is designed, which contains two joinable parts: one U‐shaped multilayered TENG unit, and three trigger ends chosen according to actual requirements. The joinable design can directly reduce the waterproof treatment of U‐shaped multilayer section, performance degradation caused by humidity, and effectively avoids electrostatic shielding caused by water and corrosion of triboelectric materials. Furthermore, different forms of hydropower collection, such as the energy of surface water wave, underwater wave/flow, and water droplet can be achieved using the corresponding trigger end. This study provides a feasible scheme for efficient and economical multiform hydropower collection based on triboelectric technology. [ABSTRACT FROM AUTHOR]

In this study, a three‐step remaining service life (RSL) prediction method, which involves feature extraction, feature selection, and fusion and prognostics, is proposed for large‐scale rotating machinery in the presence of scarce failure data. In the feature extraction step, eight time‐domain degradation features are extracted from the faulty variables. A fitness function as a weighted linear combination of the monotonicity, robustness, correlation, and trendability metrics is defined and used to evaluate the suitability of the features for RSL prediction. The selected features are merged using a canonical variate residuals‐based method. In the prognostic step, gray model is used in combination with empirical Bayesian algorithm for RSL prediction in the presence of scarce failure data. The proposed approach is validated on failure data collected from an operational industrial centrifugal pump and a compressor. [ABSTRACT FROM AUTHOR]

Aggregation‐induced emission (AIE) materials have drawn great attention for applications as organic light‐emitting diodes (OLED) and probes. The applications are, however, restricted by the complex syntheses and hydrophobic properties. Herein, a one‐step synthesis of an AIE material based on imidazole hydrazone is assessed. Protonation of the imidazole‐H leads to emission color change from yellow to green in the solid state. The emission color is recovered upon imidazole‐H+ deprotonation. Moreover, the emission wavelength shifts from 532 to 572 nm by anion exchange. In addition, an enhanced emission (ΦF up to 22.6 %) was obtained with the Br− anion compared with NTf2−, SbCl5−, PF6−, and OTf− anions. X‐ray crystallography studies together with theoretical calculations show that the enhanced emission of hydrazone salts arises from strong hydrogen bonding between the hydrazone proton and the halide ion (Cl− or Br−). [ABSTRACT FROM AUTHOR]

A column dust scrubber based on an orifice plate is developed for small and medium‐sized enterprises in China, which urgently need small‐volume, large‐flow scrubbers. The scrubber uses an orifice plate to evenly distribute the gas flow, which forms a uniform and stable impact on the liquid phase. As a result, dust removal via intensified gas‐liquid mixing can be achieved. A laboratory orifice plate scrubber model is developed, prototyped, and preliminarily studied considering the working process of the scrubber (mixed gas‐liquid flow pattern), liquid level, gas flow rate, pressure drop characteristics, dust removal efficiency, etc. The scrubber can achieve a good gas‐liquid mixing state when it is in a stable liquid column flow pattern. The drag coefficient of the scrubber is affected by the discharge of the gas stream to the liquid phase. [ABSTRACT FROM AUTHOR]

An economical and efficient approach to pharmaceutically and biologically significant 2,3‐dihydroquinazolin‐4(1H)‐ones has been disclosed. The one‐pot multicomponent reaction was performed through a palladium‐catalyzed ortho‐selective oxidative carbonylation of N‐substituted anilines with CO and primary amines, and subsequent condensation with aldehydes in MeCN by using alkylamino as the directing group, KI/AcOH as the additives, and Cu(OAc)2 as the oxidant. This intriguing straightforward method features embedded directing strategy, simple starting materials, mild conditions, high atom/step economic economy, broad substrate scope and good product diversity. [ABSTRACT FROM AUTHOR]

In this contribution, a new highly selective colorimetric chemosensors based on naphthalimide and coumarin was synthesized and characterized by NMR and mass spectroscopic techniques. In the presence of F-or OH-, the sensor change its color from light yellow to deep blue, which can easily be observed by the naked eye. The sensor shows good selectivity against other common anions. The effects of deprotonation/protonation on the absorption characteristics were investigated. The underlying signalling mechanism is photoinduced charge transfer (PCT). The observed effects of deprotonation upon colour were interpreted by the quantum chemical calculations of HOMO/LUMO and energy gap.(© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

In this contribution, a new naphthalimide dimer with A- π -D- π -A framework was synthesized efficiently and well characterized. Its spectral properties were investigated. Significant features, such as strong solid and liquid fluorescence, usual large Stokes shift were discussed in terms of its electronic structures. In addition, it is soluble in common organic solvent and stable at ambient conditions. Optimized molecular structure shows the twisted molecular conformation, which leads to its narrow solid emission. Frontier orbital calculation indicates effective excited-state intramolecular charge transfer (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Abstract: Objective: To investigate clinical characteristics of usual-type vulvar intraepithelial neoplasia (uVIN) in China. Methods: A retrospective review of the records of 64 patients with uVIN was performed at 3 academic hospitals between 2004 and 2010. Patients were assigned to a younger (≤40years) or an older (>40years) group. Clinical characteristics of lesions were described and analyzed. Results: Mean patient age was 40.6years. There was a high proportion of incidental findings (34%), multifocal lesions (64%), variegated lesions (59%), and multiple neoplastic lesions in the lower genital tract (20%). As patient age increased, so did numbers of patients reporting pain (P <0.05). Longer time between symptom onset and uVIN diagnosis, and more multifocal lesions were noted in the older group (P <0.05). Whereas younger patients often presented with cervical intraepithelial neoplasia and uVIN, older patients often presented with intraepithelial neoplasia at uncommon locations (e.g. vagina, anus, and periurethral region) (P <0.05). No differences between the groups were found regarding gross appearance or anatomic location of uVIN lesions (P >0.05). Conclusion: Age-specific differences were noted in location of neoplastic lesions in the lower genital tract and time to diagnosis of uVIN. However, the clinical features of uVIN lesions were heterogeneous and non-age specific. [Copyright &y& Elsevier]