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Effect of Pretreatments on the Enzymatic Hydrolysis of High-Yield Bamboo Chemo-Mechanical Pulp by Changing the Surface Lignin Content
No full textHydrogen peroxide chemo-mechanical pulp (APMP), sulfonated chemo-mechanical pulp (SCMP), and chemical thermomechanical pulp (CTMP) were used as raw materials to explore the effects of hydrogen peroxide (HP), Fenton pretreatment (FP), and ethanol pretreatment (EP) on the enzymatic hydrolysis of high-yield bamboo mechanical pulp (HBMP). The surface lignin distribution and contents of different HBMPs were determined using confocal laser scanning microscopy (CLSM) and X-ray photoelectron spectroscopy (XPS). The correlation between the surface lignin and the enzymatic hydrolysis of HBMP was also investigated. The residue of enzymatic hydrolysis was used to adsorb methylene blue (MB). The results showed that the cracks and fine fibers on the surface of APMP, SCMP, and CTMP increased after FP, when compared to HP and EP. The total removal content of hemicellulose and lignin in SCMP after FP was higher than with HP and EP. Compared to SCMP, the crystallinity increased by 15.4%, and the surface lignin content of Fenton-pretreated SCMP decreased by 11.7%. The enzymatic hydrolysis efficiency of HBMP after FP was higher than with HP and EP. The highest enzymatic hydrolysis of Fenton-pretreated SCMP was 49.5%, which was higher than the enzymatic hydrolysis of Fenton-pretreated APMP and CTMP. The removal rate of MB reached 94.7% after the adsorption of the enzymatic hydrolysis residue of SCMP. This work provides an effective approach for a high value-added utilization of high-yield bamboo pulp
Carbon Fiber Reinforced Multi-Phase Epoxy Syntactic Foam (CFR-Epoxy-Hardener/HGMS/Aerogel-R-Hollow Epoxy Macrosphere(AR-HEMS))
No full textBecause the aerogel has ultra-low density and good impact resistance, the aerogel material, epoxy-hardener system, and expandable polystyrene beads (EPS) were used to prepare the lightweight aerogel reinforced hollow epoxy macro-spheres (AR-HEMS). The multi-phase epoxy syntactic foam (ESF) was manufactured with the epoxy-hardener system, HGMS (EP-hardener-HGMS), and AR-HEMS by the compression modeling method. In this experiment, in order to enhance the strength of the ESF, some different kinds of the carbon fiber (CF) were added into the EP-hardener-HGMS system (CFR-EP). The influence of the volume stacking fraction, inner diameter, and layer of the AR-HEMS and the content and type of the CF in the EP-HGMS (CFR-EP) system on the compressive strength of the ESF were studied. Weighing the two factors of the density and compressive strength, the ESF reinforced by 1.5 wt% CF with 90% AR-HEMS has the better performance. This kind of the ESF has 0.428 g/cm(3) nd 20.76 Mpa, which could be applied in 2076 m deep sea
Metal-Free Organo-Theranostic Nanosystem with High Nitroxide Stability and Loading for Image-Guided Targeted Tumor Therapy
No full textThe desire for all-organic-composed nanoparticles (NPs) of considerable biocompatibility to simultaneously diagnose and treat cancer is undeniably interminable. Heretofore, metal-based agents dominate the landscape of available magnetic resonance imaging (MRI) contrast agents and photothermal therapeutic agents, but with associated metal-specific downsides. Here, an all-organic metal-free nanoprobe, whose appreciable biocompatibility is synergistically contributed by its tetra-organo-components, is developed as a viable alternative to metal-based probes for MRI-guided tumor-targeted photothermal therapy (PTT). This rationally entails a glycol chitosan (GC)-linked polypyrrole (PP) nanoscaffold that provides abundant primary and secondary amino groups for amidation with the carboxyl groups in a nitroxide radical (TEMPO) and folic acid (FA), to obtain GC-PP@TEMPO-FA NPs. Advantageously, the appreciably benign GC-PP@TEMPO-FA features high nitroxide loading (r(1) = 1.58 mM(-1) s(-1)) and in vivo nitroxide-reduction resistance, prolonged nitroxide-systemic circulation times, appreciable water dispersibility, potential photodynamic therapeutic and electron paramagnetic resonance imaging capabilities, considerable biocompatibility, and ultimately achieves a 17 h commensurate MRI contrast enhancement. Moreover, its GC component conveys a plethora of PP to tumor sites, where FA-mediated tumor targeting enables substantial NP accumulation with consequential near-complete tumor regression within 16 days in an MRI-guided PTT. The present work therefore promotes the engineering of organic-based metal-free biocompatible NPs in synergism, in furtherance of tumor-targeted image-guided therapy
Neel-Type Elliptical Skyrmions in a Laterally Asymmetric Magnetic Multilayer
No full textMagnetic skyrmions, topological-chiral spin textures, have potential applications in next-generation high-density and energy-efficient spintronic devices for information storage and logic technologies. Tailoring the detailed spin textures of skyrmions is of pivotal importance for tuning skyrmion dynamics, which is one of the key factors for the design of skyrmionic devices. Here, the direct observation of parallel aligned elliptical magnetic skyrmions in Pt/Co/Ta multilayers with an oblique-angle deposited Co layer is reported. Domain wall velocity and spin-orbit-torque-induced out-of-plane effective field analysis demonstrate that the formation of unusual elliptical skyrmions is correlated to the anisotropic effective perpendicular magnetic anisotropy energy density (K-u(eff)) and Dzyaloshinskii-Moriya interaction (DMI) in the film plane. Structural analysis and first-principles calculations further show that the anisotropic K-u(eff) and DMI originate from the interfacial anisotropic strain introduced by the oblique-angle deposition. The work provides a method to tune the spin textures of skyrmions in magnetic multilayers and, thereby, a new degree of freedom for the design of skyrmionic devices
Ultrathin flexible InGaZnO transistor for implementing multiple functions with a very small circuit footprint (vol 14, pg 232, 2021)
No full textFigure 1 (d) To implement an NAND gate, the traditional design uses 3 transistors, the latest report uses 2 transistors [14], and the single transistor design uses 1 transistor
Europium Nanocomplex for Development of Latent Fingerprints Based on Carboxyl Activation Mechanism
No full textAn activated carboxyl-based approach for latent fingerprint development with high quality and high efficiency was proposed. Firstly , carboxyl-functionalized fluorescent europium nanocomplex was chemically synthesized via a one-step process by using europium (III) ion as the luminescence center, phthalic acid as the first ligand , and phenanthroline as the second ligand. Then , the micromorphology , crystal structure , ultraviolet absorption property, fluorescent emission performance, surface functional groups and thermal property of these synthesized europium nanocomplex were characterized by transmission electron microscopy , powder X-ray diffractometer, , ultraviolet-visible spectrophotometer, fluorescence spectrophotometer, Fourier transform infrared spectrometer and simultaneous thermal analyzer, respectively. The carboxyl groups on the surface of europium nanocomplex were further activated using 1- (3 -dimethylaminopropyl) -3 -ethylcarbodiimide hydrochloride combined with N-hydroxysuccinimide. The activated carboxyl groups on the surface of europium nanocomplex could easily react with the amino groups in latent fingerprint through amide reaction , and the latent fingerprint was thus fluorescently developed with high efficiency. The mechanism of latent fingerprint development based on activated carboxyl process was discussed in detail, and the nanocomplex dosage and the staining time in developing suspension were also systematically optimized. In addition , the effects in fingerprint development were investigated from three aspects including contrast, sensitivity and selectivity. Experimental results showed that, the activated carboxyl-based approach could achieve a high performance in latent fingerprint development, exhibiting high efficiency, good operability and wide applicability
Robust and durable flexible micro-supercapacitors enabled by graphene nanoscrolls
No full textThe rise of miniaturized, flexible and self-powered electronic systems has substantially stimulated the urgent demand for microscale electrochemical energy storage devices. Impressively, planar micro-supercapacitors (MSCs) are playing a crucial role because of fast ion transmission, ultra-long lifetime, and being easily integrated with microelectronic devices. Unfortunately, the robustness of film electrodes in MSCs usually cannot satisfy the structural stability of the film electrodes and the durability of the devices. Here, a novel strategy to address the problem is proposed by introducing graphene nanoscrolls with high aspect ratio as the active materials in the flexible MSCs to enhance the robustness of the film electrode because of their intertwined one-dimensional nanostructures. The as-prepared bendable MSC can maintain nearly 100% of initial capacitance when bent for 1000 cycles, and the stretchable MSC can maintain 88% of initial capacitance when stretched at a high stress ratio of 100% for 1000 cycles. This study provides an effective strategy to build up robust film electrodes for MSCs and improve the durability of the flexible MSCs
Spontaneously formation of SEI layers on lithium metal from LiFSI/DME and LiTFSI/DME electrolytes
No full textLithium is a highly reactive metal that can react with most of the organic electrolytes. Here, we report the spontaneous formation of solid electrolyte interphase (s-SEI) on the surface of lithium metal. We focused on investigating the differences in the properties of s-SEI layers, formed in the electrolyte 1M LiFSI (lithium bisfluorosulfonimide)/DME (dimethyl ether) or 1M LiTFSI [lithium bis((trifluoromethyl)sulfonyl)azanide]/DME with the extension of soaking time. Morphology, structural peculiarities and mechanical properties of the s-SEI were investigated by AFM. At the same time, in-depth XPS profile analysis revealed that the s-SEI layers were similar to the electrochemically reduced SEI layers, mainly composed of inorganic components, such as LiF, Li3N, organic components of alkyl lithium carbonate (ROCO2Li) and lithium alkylates (ROLi). Cu/Li and Li/Li symmetric cells showed that the thickened s-SEI layers could increase the polarization potential of plating/stripping, while Li3N riched s-SEI has the effect of reducing polarization potential
( )Role of electrolytes on the electrochemical characteristics of Fe3O4/MXene/RGO composites for supercapacitor applications
No full textThis study aims at developing hybrid composite materials consisting of iron oxide (Fe3O4) /MXene /reduced graphene oxide (RGO) without any impurities using optimized experimental parameters to be utilized in next-generation supercapacitor applications and the searching of suitable electrolyte for the developed hybrid electrode materials. We have generated Fe3O4-decorated MXene nanosheets on RGO by a simple chemical oxidation method. The initial grain size of Fe3O4 of about 43 nm is further reduced to 30 nm when prepared with MXene nanosheets. The as-prepared samples are used as a negative electrode material and their capacitive performance is analyzed in potassium hydroxide (KOH), sodium sulphate (Na2SO4) and lithium chloride (LiC1) electrolytes. Fe3O4/MXene/RGO nanocomposites showed the best performance. Regarding the electrolytes, the following order has been obtained 5 M LiC1 > 1 M Na2SO4 > 1 M KOH, which matches well with the bare ion size order. Moreover, Fe3O4/MXene/RGO electrode exhibits an 82.1% of cyclic stability up to 5000 charge/discharge cycles at a current density of 5 A g(-1) demonstrating the best performance. (C) 2020 Elsevier Ltd. All rights reserved
Potassium Ions Induced Framework Interpenetration for Enhancing the Stability of Uranium-Based Porphyrin MOF with Visible-Light-Driven Photocatalytic Activity
No full textThe stability of many MOFs is not satisfactory, which severely limits the exploration of their potential applications. Given this, we have proposed a strategy to improve the stability of MOFs by introducing alkali metal K+ capable of coordinating with metal nodes, which finally induces the interpenetrating uranyl-porphyrin framework to connect as a whole (IHEP-9). The stability experiments reveal that the IHEP-9 has good thermal stability up to 400 degrees C and can maintain its crystalline state in the aqueous solution with pH ranging from 2 to 11. The catalytic activity of IHEP-9 as a heterogeneous photocatalyst for CO2 cycloaddition under the driving of visible light at room temperature is also demonstrated. This induced interpenetration and fixation method may be promising for the fabrication of more functional MOFs with improved structural stability