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排序方式: 共有5018条查询结果,搜索用时 17 毫秒
1.
An ecofriendly and biodegradable porous structure was prepared from drying aqueous foams based on nano fibrillated cellulose (NFC), extracted from softwood pulp by subcritical water/CO2 treatment (SC-NFC). The primary aim of this work was to use the modified SC-NFC as stabilizer for a water-based Pickering emulsion which upon drying, yielded porous cellulosic materials, a good dye adsorbent. In order to exploit the carboxymethylated SC-NFC (CMSC-NFC, with a degree of substitution of 0.35 and a charge density of 649 μeqv/g) as a stabilizer for water-based Pickering emulsion in subsequent step, an optimized quantity of octyl amine (30 mg/g of SC-NFC) was added to make them partially hydrophobic. A series of dry foam structures were prepared by varying the concentrations of treated CMSC-NFCs and 4 wt% was found to be the optimum concentration to yield foam with high porosity (99%) and low density (0.038 g/cc) along with high compression strength (0.24 MPa), superior to the conventionally extracted NFC. The foams were applied to capture as high as 98% of methylene blue dyes, making them a potential green candidate for treating industrial effluent. In addition, the dye adsorption kinetics and isotherms were found to be well suited with second order kinetics and Langmuir isotherm models. 相似文献
2.
《Ceramics International》2021,47(23):32610-32618
AA7075 + 6%B4C+3%ZrC nano hybrid composite was successfully fabricated, with nano reinforcements composition in AA7075 alloy selected based on previous investigation, to achieve better mechanical performance. Two different sintering techniques, namely conventional and microwave, were implemented to determine the effect on microstructural and mechanical properties. Microstructural investigation was performed with the help of W-SEM. Tensile, compression, and hardness were measured with the help of UTM and Vickers microhardness machine. Porosity was calculated by using Archimedes principle. It was observed that the added nano ZrC particles formed agglomerates and the B4C particles were distributed homogenously. Composites processed by microwave sintering showed excellent mechanical properties compared to the conventionally sintered composites. No intermetallic compounds were detected in microwave sintered composites through XRD analysis, indicating strong and clean interface bonds between matrix and reinforcement particles. High strain to fracture value of 12.24% was noted in microwave sintered nano hybrid composite, while it was 6.12% for conventional sintered one. Fractography revealed no peeling action of reinforcements from the matrix material, and the mode of failure was brittle. It was concluded that, while fabricating nano range hybrid composites, the implementation of advanced sintering technique (microwave sintering) with low sintering temperatures and low sintering times with internal heat generations, helps in eliminating defects that may develop because of high surface energies of nano range reinforcements. 相似文献
3.
《International Journal of Hydrogen Energy》2022,47(22):11500-11510
Herein, a novel ZnTe-based photocatalyst is successfully synthesized via a facile combination of water-bath and hydrothermal processes. Morphology characterization and X-ray diffraction analysis reveal that ZnTe presents irregular granular shape and cubic crystal structure. Moreover, Mott-Schottky measurement shows that the conduction band potential of ZnTe is ?0.84 V (vs NHE). With Eosin Y (EY) sensitization, ZnTe exhibits superior photocatalytic hydrogen evolution activity (223.5 μmol g?1 h?1). Meanwhile, WC-ZnTe heterojunction is constructed by depositing ZnTe nanoparticles on bulk WC and obtains the optimal H2 generation rate (559.1 μmol g?1 h?1) under EY sensitization. Electrochemical and photoluminescence results further prove that WC as electron bridge could reduce the interfacial resistance and suppress e?-h+ pairs recombination. This study explores the potential application of ZnTe as a newly active photocatalyst in photocatalytic water splitting, and emphasizes the synergistic effect of dye sensitization and bridge engineering. 相似文献
4.
Water contamination is a global challenge impacting both the environment and human health with significant economic and social costs. The growing scarcity of usable water resources requires effective treatment of wastewater. In this context, developing cheaper, safer and more efficient wastewater treatment technologies are the need of the hour. One promising approach that several studies have reported success has been the usage of nanomaterials in water and waste water management. The rapid progress of research in nanomaterial sciences has shown their growing potential; however, there has not been a great amount of information available on their implementation. This review focuses on developments in nanotechnology that hold strong potential for wastewater treatment. The review covers key techniques in nanomaterial‐based water treatments including adsorption, filtration and photocatalysis with recent examples showing how to improve their properties and efficiencies according to the need. 相似文献
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为探究挠性筋结构单晶硅材料的各向异性特性以及KOH腐蚀工艺对其力学性能的影响规律,进行纳米压痕实验,并结合原子力显微镜观察单晶硅表层3个主晶面上压痕裂纹形貌随晶向的变化规律,分析单晶硅材料表层弹性模量、硬度、断裂韧性等机械力学特性参数在(001)、(110)及(111)3个主要晶面上沿各个晶向的变化规律;分析挠性筋结构单晶硅材料(001)晶面的KOH腐蚀工艺对其材料表面机械特性的影响规律.结果表明:挠性筋单晶硅在(001)晶面上弹性模量的各向异性变化幅度明显,硬度及断裂韧性各向异性的变化幅度不大;挠性筋单晶硅在(110)晶面弹性模量和断裂韧性的各向异性变化幅度明显,硬度各向异性变化幅度不大;挠性筋单晶硅在(111)晶面硬度值、弹性模量及断裂韧性参数的变化幅度幅值均较小;确定了单晶硅表层3个晶面裂纹最易扩展的晶向方向,KOH腐蚀工艺使得单晶硅表面质量降低,腐蚀后暴露的表面微裂纹、缺陷等会使得单晶硅(001)晶面表层硬度、断裂韧性降低,从而降低了挠性筋结构的实际断裂强度. 相似文献
7.
Luca Pezzato Leonardo Bertolucci Coelho Rachele Bertolini Alessio Giorgio Settimi Katya Brunelli Marjorie Olivier Manuele Dabal 《工业材料与腐蚀》2019,70(11):2103-2112
Plasma electrolytic oxidation (PEO) coatings were produced on AZ80 magnesium alloy in a solution containing silicates and phosphates and working at high current densities with short treatment times. The effect of a sealing treatment in boiling water on corrosion and mechanical properties of the coatings were investigated. Moreover, the corrosion mechanism of the samples with and without the sealing treatment was evaluated. The microstructure of the coatings was characterized with scanning electron microscope observation and X‐ray diffraction analysis. The mechanical properties were evaluated with nanoindentation tests and the corrosion resistance was studied by potentiodynamic polarization, electrochemical impedance spectroscopy, and scanning vibrating electrode technique. The results showed that the sealing did not influence the microstructure and the mechanical properties of the samples and instead produced a remarkable increase in the corrosion resistance. The crevice corrosion, present in the sample without the sealing, was avoided with the treatment in boiling water. 相似文献
8.
Akihiro Nishiguchi Fumisato Sasaki Hidehito Maeda Masayuki Kabayama Akio Ido Tetsushi Taguchi 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(35)
Endoscopic submucosal dissection (ESD) provides strong therapeutic benefits for early gastrointestinal cancer as a minimally invasive treatment. However, there is currently no reliable treatment to prevent scar contracture resulting from ESD which may lead to cicatricial stricture. Herein, a multifunctional colloidal wound dressing to promote tissue regeneration after ESD is demonstrated. This sprayable wound dressing, composed of hydrophobized microparticles, exhibits the multifunctionality necessary for wound healing including tissue adhesiveness, blood coagulation, re‐epithelialization, angiogenesis, and controlled inflammation based on hydrophobic interaction with biological systems. An in vivo feasibility study using swine gastric ESD models reveals that this colloidal wound dressing suppresses fibrosis and accelerates wound healing. Multifunctional colloidal and sprayable wound dressings have an enormous therapeutic potential for use in a wide range of biomedical applications including accelerated wound healing after ESD, prevention of perforation, and the treatment of inflammatory diseases. 相似文献
9.
Xiaoqiang Li Ting Cao Minai Zhang Hao Qiu Yang Huang Shengguan Qu Liang Liang Tao Song 《International Journal of Applied Ceramic Technology》2020,17(3):941-948
Porous fibers are widely used in catalysis chemistry and hydrogen storage but are rarely used in structural ceramics. In this study, spark plasma sintering was used to prepare an ultrafine porous boron nitride nanofiber-toughened WC composite for the first time. The obtained WC-0.05 wt% ultrafine porous boron nitride nanofiber composites exhibited better properties (ie, a 2.3% increase in hardness and a 19.6% increase in fracture toughness) compared to those of the pure WC specimen. The fiber porosity improved the second phase-WC matrix microstructural combination. The described approach is a novel preparation method for the WC composites. Furthermore, a new toughening mechanism, which is based on “pinning and stretching”, was determined. These findings suggest that porous boron nitride fibers can be considered to be second phases for toughening the WC composites. 相似文献
10.
Multicellular tumor spheroid models (MCTS) are often coined as 3D in vitro models that can mimic the microenvironment of tissues. MCTS have gained increasing interest in the nano‐biotechnology field as they can provide easily accessible information on the performance of nanoparticles without using animal models. Considering that many countries have put restrictions on animals testing, which will only tighten in the future as seen by the recent developments in the Netherlands, 3D models will become an even more valuable tool. Here, an overview on MCTS is provided, focusing on their use in cancer research as most nanoparticles are tested in MCTS for treatment of primary tumors. Thereafter, various types of nanoparticles—from self‐assembled block copolymers to inorganic nanoparticles, are discussed. A range of physicochemical parameters including the size, shape, surface chemistry, ligands attachment, stability, and stiffness are found to influence nanoparticles in MCTS. Some of these studies are complemented by animal studies confirming that lessons from MCTS can in part predict the behaviour in vivo. In summary, MCTS are suitable models to gain additional information on nanoparticles. While not being able to replace in vivo studies, they can bridge the gap between traditional 2D in vitro studies and in vivo models. 相似文献