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Alla Berezina, Tetiana Monastyrska, Olexandr Davydenko, Oleh Molebny, Sergey Polishchuk
The comparative analysis of the effect of monotonous and non-monotonous severe plastic deformations (SPD) on the structure and properties of aluminum alloys has been carried out. Conventional hydrostatic extrusion (HE) with a constant deformation direction and equal-channel angular hydroextrusion (ECAH) with an abrupt change in the deformation direction were chosen for the cases of monotonous and non-monotonous SPD, respectively. Model cast hypoeutectic Al-0.3%Sc alloys and hypereutectic Al-0.6%Sc alloys with Ta and Ti additives were chosen for studying...
December 2017: Nanoscale Research Letters
Chinnannan Karthik, Selvaraj Barathi, Arivalagan Pugazhendhi, Vijayan Sri Ramkumar, Ngoc Bao Dung Thi, Padikasan Indra Arulselvi
The present study, a novel haloalkaliphilic Cr(VI) tolerant bacterial strain, Cellulosimicrobium funkei AR8, was isolated and characterized for its high Cr(VI) reduction. In batch experiments, Cr(VI) reduction was evaluated under different parametric conditions which include different pH (5-9), temperature (25-45°C), NaCl (0-3%) and Cr(VI) concentrations (100-250μg/ml). Variations in the cell surface functional groups and morphology of the bacterial cells after Cr(VI) reduction were characterized by FT-IR and SEM-EDX...
March 18, 2017: Journal of Hazardous Materials
Junichi Shimanuki, Shinichi Takahashi, Hajime Tohma, Atsushi Ohma, Ayumi Ishihara, Yoshiko Ito, Yuri Nishino, Atsuo Miyazawa
In order to improve the electricity generation performance of fuel cell electric vehicles, it is necessary to optimize the microstructure of the catalyst layer of a polymer electrolyte fuel cell. The catalyst layer is formed by a wet coating process using catalyst inks. Therefore, it is very important to observe the microstructure of the catalyst ink. In this study, the morphology of carbon-supported platinum (Pt/C) particles in catalyst inks with a different solvent composition was investigated by cryogenic scanning electron microscopy (cryo-SEM)...
February 9, 2017: Microscopy
Takahiro Tamura, Yoshihide Kimura, Yoshizo Takai
We have developed a real-time wave field reconstruction transmission electron microscope system that enables auto focus tracking at a video rate. In the developed system, a high-speed image calculation technique using a graphical processing unit was incorporated along with two techniques facilitating high-speed focus control using high-voltage modulation and weighted image integration using exposure time control. By utilizing these techniques, the sample drift induced in the Z-axis direction can be measured and automatically corrected for every 1/30 of a second...
February 18, 2017: Microscopy
Kazuhiro Aoyama, Kotaro Nagano, Kaoru Mitsuoka
For three-dimensional analysis of cryo-specimens using tomography at low and medium magnifications, the use of STEM images has some important advantages over TEM. A clear understanding of the electron dose in STEM is essential for optimized cryo-microscopy so a dose estimation technique for STEM imaging has been developed. The STEM convergence angle was shown to have a large impact on the image quality, in particular on the signal-to-noise ratio in the acquired images. Importantly, there is a clear trade-off between good STEM spatial resolution in the images with a large convergence angle and the signal-to-noise ratio, which is improved by reducing the convergence angle as much as possible...
February 9, 2017: Microscopy
Preeyanuch Sangtrirutnugul, Thanawat Chaiprasert, Warodom Hunsiri, Thanudkit Jitjaroendee, Patsaya Songkhum, Kritapas Laohhasurayotin, Tanakorn Osotchan, Vuthichai Ervithayasuporn
Polyhedral oligomeric silsesquioxane (POSS)-based materials, poly-POSS-Tn [n = 8 (1), 10 (2), 12 (3), and mix (4)], were prepared in high yields via free radical polymerization of corresponding pure forms of methacrylate-functionalized POSS monomers, MMA-POSS-Tn (n = 8, 10, 12), and the mixture form, MMA-POSS-Tmix. Powder X-ray diffraction (XRD) spectra and BET analysis indicate that 1-4 are amorphous materials with high surface areas (683-839 m2•g-1). The surface areas and total pore volumes follow the trend: poly-POSS-T12 > poly-POSS-T10 > poly-POSS-Tmix > poly-POSS-T8...
March 24, 2017: ACS Applied Materials & Interfaces
Lingzhi Zhao, Liu Zhao, Yanqing Miao, Chunye Liu, Chenxiao Zhang
Hydrogen sulfide (H₂S) has attracted attention in biochemical research because it plays an important role in biosystems and has emerged as the third endogenous gaseous signaling compound along with nitric oxide (NO) and carbon monoxide (CO). Since H₂S is a kind of gaseous molecule, conventional approaches for H₂S detection are mostly based on the detection of sulfide (S(2-)) for indirectly reflecting H₂S levels. Hence, there is a need for an accurate and reliable assay capable of determining sulfide in physiological systems...
March 20, 2017: Sensors
Yonghui Chen, Chen Xu, Yibo Zhou, Khan Maaz, Huijun Yao, Dan Mo, Shuangbao Lyu, Jinglai Duan, Jie Liu
Parallel arrays of Ni nanotubes with an external diameter of 150 nm, a wall thickness of 15 nm, and a length of 1.2 ± 0.3 µm were successfully fabricated in ion-track etched polycarbonate (PC) templates by electrochemical deposition. The morphology and crystal structure of the nanotubes were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Structural analyses indicate that Ni nanotubes have a polycrystalline structure with no preferred orientation...
December 1, 2016: Nanomaterials
Seong Baek Yang, Mohammad Mahbub Rabbani, Byung Chul Ji, Dong-Wook Han, Joon Seok Lee, Jong Won Kim, Jeong Hyun Yeum
The optimum conditions for the fabrication of zein/Ag composite nanoparticles from ethanol/H₂O cosolvents using electrospinning and the properties of the composite were investigated. The zein/Ag nanoparticles were characterized using field-emission scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), and thermogravimetric analysis. The antibacterial activity of the zein/Ag composite nanoparticles was also investigated. The XRD patterns and TEM images indicate the coexistence of a zein matrix and well-distributed Ag nanoparticles...
December 1, 2016: Nanomaterials
Baomin Wang, Ruishuang Jiang, Zhenlin Wu
In this work, graphene nanoplatelets (GNPs) were dispersed uniformly in aqueous solution using methylcellulose (MC) as a dispersing agent via ultrasonic processing. Homogenous GNP suspensions were incorporated into the cement matrix to investigate the effect of GNPs on the mechanical behavior of cement paste. The optimum concentration ratio of GNPs to MC was confirmed as 1:7 by ultraviolet visible spectroscopy (UV-Vis), and the optical microscope and transmission electron microscopy (TEM) images displayed remarkable dispersing performance...
November 4, 2016: Nanomaterials
Juan Carlos Calderón, Miguel Rios Ráfales, María Jesús Nieto-Monge, Juan Ignacio Pardo, Rafael Moliner, María Jesús Lázaro
In this work, palladium-nickel nanoparticles supported on carbon nanofibers were synthesized, with metal contents close to 25 wt % and Pd:Ni atomic ratios near to 1:2. These catalysts were previously studied in order to determine their activity toward the oxygen reduction reaction. Before the deposition of metals, the carbon nanofibers were chemically treated in order to generate oxygen and nitrogen groups on their surface. Transmission electron microscopy analysis (TEM) images revealed particle diameters between 3 and 4 nm, overcoming the sizes observed for the nanoparticles supported on carbon black (catalyst Pd-Ni CB 1:2)...
October 18, 2016: Nanomaterials
Qian Hua Xia, Yan Jun Ma, Jian Wen Wang
Plant constituents could act as chelating/reducing or capping agents for synthesis of silver nanoparticles (AgNPs). The green synthesis of AgNPs has been considered as an environmental friendly and cost-effective alternative to other fabrication methods. The present work described the biosynthesis of AgNPs using callus extracts from Taxus yunnanensis and evaluated their antibacterial activities in vitro and potential cytotoxicity in cancer cells. Callus extracts were able to reduce silver nitrate at 1 mM in 10 min...
September 1, 2016: Nanomaterials
Ko-Ying Pan, Da-Hua Wei
Substantial synthetic vanadium pentoxide (V₂O₅) nanowires were successfully produced by a vapor-solid (VS) method of thermal evaporation without using precursors as nucleation sites for single crystalline V₂O₅ nanowires with a (110) growth plane. The micromorphology and microstructure of V₂O₅ nanowires were analyzed by scanning electron microscope (SEM), energy-dispersive X-ray spectroscope (EDS), transmission electron microscope (TEM) and X-ray diffraction (XRD). The spiral growth mechanism of V₂O₅ nanowires in the VS process is proved by a TEM image...
July 29, 2016: Nanomaterials
Yinxue Zu, Jingran Bi, Huiping Yan, Haitao Wang, Yukun Song, Bei-Wei Zhu, Mingqian Tan
Fluorescent nanostructures (NSs) derived from polysaccharides have drawn great attention as novel fluorescent probes for potential bio-imaging applications. Herein, we reported a facile alkali-assisted hydrothermal method to fabricate polysaccharide NSs using starch and chitosan as raw materials. Transmission electron microscopy (TEM) demonstrated that the average particle sizes are 14 nm and 75 nm for starch and chitosan NSs, respectively. Fourier transform infrared (FT-IR) spectroscopy analysis showed that there are a large number of hydroxyl or amino groups on the surface of these polysaccharide-based NSs...
July 5, 2016: Nanomaterials
Lidong Cao, Huirong Zhang, Chong Cao, Jiakun Zhang, Fengmin Li, Qiliang Huang
Nanotechnology-based pesticide formulations would ensure effective utilization of agricultural inputs. In the present work, mesoporous silica nanoparticles (MSNs) with particle diameters of ~110 nm and pore sizes of ~3.7 nm were synthesized via a liquid crystal templating mechanism. A water-soluble chitosan (CS) derivative (N-(2-hydroxyl)propyl-3-trimethyl ammonium CS chloride, HTCC) was successfully capped on the surface of pyraclostrobin-loaded MSNs. The physicochemical and structural analyses showed that the electrostatic interactions and hydrogen bonding were the major forces responsible for the formation of HTCC-capped MSNs...
June 28, 2016: Nanomaterials
Penghong Liu, Shaohua Wu, Yue Zhang, Hongnan Zhang, Xiaohong Qin
Highly orientated polypyrrole (PPy)-coated polyacrylonitrile (PAN) (PPy-PAN) nanofiber yarn was prepared with an electrospinning technique and in-situ chemical polymerization. The morphology and chemical structure of PPy-PAN nanofiber yarn was characterized by scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and fourier transform infrared spectroscopy (FTIR), which indicated that the PPy as the shell layer was homogeneously and uniformly polymerized on the surface of PAN nanofiber...
June 23, 2016: Nanomaterials
Siqi Huang, Jing Wang, Yang Zhang, Zhiming Yu, Chusheng Qi
A facile, efficient, and eco-friendly approach for the preparation of uniform silver nanoparticles (Ag NPs) was developed. The synthesis was conducted in an aqueous medium exposed to microwave irradiation for 8 min, using laboratory-prepared, water-soluble quaternized carboxymethyl chitosan (QCMC) as a chemical reducer and stabilizer and silver nitrate as the silver source. The structure of the prepared QCMC was characterized using Fourier transform infrared (FT-IR) and ¹H nuclear magnetic resonance (NMR)...
June 17, 2016: Nanomaterials
Jiangdong Yu, Zhi Wu, Cheng Gong, Wang Xiao, Lan Sun, Changjian Lin
Highly ordered, vertically oriented Fe(3+)-doped TiO₂ nanotube arrays (Fe-TNTs) were prepared on Ti-Fe alloy substrates with different Fe contents by the electrochemical anodization method. The as-prepared Fe-TNTs were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and related electrochemical techniques. XPS results demonstrated that Fe(3+) ions were successfully doped into TiO₂ nanotubes. The photoelectrochemical activity of Fe-TNTs was compared with that of pure TiO₂ nanotube arrays (TNTs)...
June 6, 2016: Nanomaterials
Luigi Tarpani, Francesco Morena, Marta Gambucci, Giulia Zampini, Giuseppina Massaro, Chiara Argentati, Carla Emiliani, Sabata Martino, Loredana Latterini
The preparation of tailored nanomaterials able to support cell growth and viability is mandatory for tissue engineering applications. In the present work, silica nanoparticles were prepared by a sol-gel procedure and were then functionalized by condensation of amino groups and by adsorption of silver nanoparticles. Transmission electron microscopy (TEM) imaging was used to establish the morphology and the average dimensions of about 130 nm, which were not affected by the functionalization. The three silica samples were deposited (1 mg/mL) on cover glasses, which were used as a substrate to culture adult human bone marrow-mesenchymal stem cells (hBM-MSCs) and human adipose-derived stem cells (hASCs)...
June 4, 2016: Nanomaterials
Ju Ying Li, Qing Song Mei
TiAl₃ and TiN composite nanoparticles were continuously synthesized from Ti-48Al master alloy by hydrogen plasma-metal reaction in a N₂, H₂ and Ar atmosphere. The phase, morphology, and size of the nanoparticles were studied by X-ray diffraction (XRD) and transmission electronic microscopy (TEM). X-ray photoelectron spectroscopy (XPS) and evolved gas analysis (EGA) were used to analyze the surface phase constitution and oxygen content of the nanoparticles. The as-synthesized nanopowders were mainly composed of nearly spherical TiAl₃ and tetragonal TiN phases, with a mean diameter of ~42 nm and mass fractions of 49...
June 1, 2016: Nanomaterials
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