Abstract The auxiliary active family 9 (AA9) of fungal lytic polysaccharide monooxygenases (LPMOs) can improve the lignocellulosic hydrolysis through an oxidative mechanism. Aspergillus niger is an important industrial producer of glycoside hydrolases, but little research on LPMOs in A. niger have been reported. This study aimed to research the biochemical characteristics of LPMOs from A. niger and the synergy with cellulase on cellulose hydrolysis. Reducing sugar produced when An LPMO14g acted on Carboxyl Methyl Cellulose (CMC), Avicel ® , xylan, filter paper, straw and corn cobs, and MALDI-TOF/TOF mass spectrometry analysis indicated that it oxidatively cleaved the glycosidic bonds of Avicel ® at C1 position. The addition of An LPMO14g into the hydrolysis systems of Avicel® and straw catalyzed by cellulase could increase the yields of reducing sugar by 92.66% and 141.42%, respectively. Homology modeling displayed that the residues H1, H86, Y175, Y24, P83 and Y212 of An LPMO14g played an important role in the catalytic process of cellulose. This study enriches the AA9 LPMO family and provides a promising candidate for the high-efficient enzyme cocktails for lignocellulose degradation.
A high static gain SEPIC based dc-dc converter is proposed in this paper. With the inclusion of a transformer and the voltage multiplier, the circuit is capable of lower switch voltage stress and high output voltage application. The input current of the converter is continuous with low ripple and the system is designed to operate under discontinuous conducting mode for soft switching. In addition, the inductors in the circuit are also used as resonant components, with detailed parameter design, a resonant stage is introduced into the switching cycle, allowing the power MOSFETs to achieve zero voltage switching (ZVS), and as a result contribute to switching loss saving and the improvement of system efficiency. Finally, a 54W 500kHz 12V/180V isolated SEPIC based converter is built to verify the validity of analysis.
This paper introduces a new method for realizing truly omnidirectional WPT without using any active control. The proposed method uses non-coherent feeds for two or more transmitting antennas, which ensures absence of any blind spots for power reception around the transmitting device. We provide analytical insights, supported by simulations and experiments, to validate our approach.
We propose a novel converter for simultaneous dual-frequency wireless power transfer (WPT) devices. The proposed converter realizes independent WPT channels at two frequencies: the main frequency f s and the second harmonic 2f s . With the coupled-T-network, a new class-Φ based push-pull inverter is introduced to provide load-independent currents for two transmitter coils. The power channels at two frequencies are decoupled and independent from each other, providing high flexibility for individual or simultaneous WPT at both frequency bands. The experimental WPT system has verified the characteristics of the proposed converter, realizing 64 W: 16 W power transfer for 6.78 MHz and 13.56 MHz receivers, respectively, with 80 % system efficiency.
Room temperature photoluminescence (PL) was observed from GeSn layers fabricated by ion implantation of Sn into bulk Ge followed by pulsed laser melting using an Nd:YAG laser at 355 nm. PL measurements indicate regions of high-crystalline quality with Sn concentrations of up to 9%.
The complicated resonant operations of class ${\Phi} _{2}$ topology bring challenges for accurate design and performance optimization, hindering the full utilization potential of converters. Considering the narrow design freedom in traditional methods with almost fixed duty cycle $D$ , this article widens the design options of push–pull class ${\Phi} _{2}$ converters through frequency-harmonic analysis. A full selection freedom of $D\in (0,0.5)$ is discussed analytically, providing ample space for optimization based on any required performance indices. From 1.98E5 analytical results, we found six numerical equations that fully decouple the interconnected relations between each circuit parameter and $D$ . The proposed numerical method allows rapid circuit design and component selection with a high accuracy regardless of the system power or load voltage. Parasitic effects are discussed and incorporated into the design approach as correction steps. Finally, we introduce performance analysis based on an example wireless power transfer (WPT) system, providing in-depth studies on the optimization regarding efficiency, power output capability, and component selection. Experimental results validate the accuracy and efficiency of the proposed design method based on a 100-W WPT system at 6.78 MHz frequency. Both inverter and rectifier present load-independent soft-switching operations, with converter efficiency over 93%. The system provides 83% dc–dc efficiency at full load.
As a micro-/nano-sized hydrogel, polymeric microgel not only has three-dimensional (3D) molecular networks but also displays the small-size effect, which has been widely used in various fields, such as drug nanocarrier, photonic crystal, functional coating, and aqueous lubrication. In this work, a photothermal lubricating coating was prepared using polymeric/inorganic hybrid microgels and its surficial friction was deliberately modulated by the remote irradiation of near-infrared (NIR) light. Specifically, a photothermal hybrid microgel, Fe3O4@poly(N-isopropylacrylamide-co-polyacrylic acid) (Fe3O4@PNA), was first fabricated and then sprayed onto poly(ethyleneimine) (PEI)-modified substrate to form a lubricating microgel coating. At room temperature, this microgel coating was hydrophilic and achieved good hydration lubrication with relatively low friction. After the introduction of NIR light, the photothermal microgel coating converted light energy into heat energy for increasing its own temperature rapidly. Due to the thermosensitive PNA shell, the wettability of the coating was transformed to hydrophobicity above the lower critical solution temperature (LCST), resulting in a remarkable increase in friction. In other words, the surficial friction of this microgel coating could be reversibly modulated using NIR light. This work expands the application scope of microgels in the field of aqueous lubrication and introduces the functional microgels into making the smart lubricating coating for the first time. This basic research in the field of friction control may provide an efficient strategy for the design of interfacial sensing, controlled transmission, and intelligent manipulator.
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