The Surface Modification of Silica with Vinyltriethoxysilane

2011 ◽  
Vol 399-401 ◽  
pp. 1123-1130 ◽  
Author(s):  
Ling Zhang ◽  
Zhi Xian Chang ◽  
De Liang Li
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Drug Carrier ◽  
Development Trend ◽  
Research Progress ◽  
Infrared Spectrometry ◽  
Existing Problems ◽  
Transmission Electron ◽  
The Development Trend

A review is provided of the research progress of silica modified with vinyltriethoxysilane (VTES-SiO2). The typical methods for preparing VTES-SiO2are introduced. The structure and stability of VTES layer and the controllability of various modified methods are elucidated. The characterization of VTES modified layer by means of Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, nuclear magnetic resonance, thermogravimetry, scanning electron microscopy and transmission electron microscopy are highlighted. Moreover, the application of VTES-SiO2 in the fields of rubber, glass, china, fiber, leather, paint, drug carrier, luminescent materials, catalyst technology, analytical chemistry and biochemistry were described in detail. The development trend on the preparation, determination of active groups and applications for VTES-SiO2were prospected, as well as the mechanism and the existing problems.

Research Progress for Determination of the Antioxidant Content in Transformer Oil

2014 ◽  
Vol 543-547 ◽  
pp. 1157-1160 ◽  
Author(s):  
Chen Yao Liu ◽  
Na Na Wang ◽  
Yun Guang Huang ◽  
Wei Wei Yu ◽  
Li Ping Zhu ◽  
...  
Keyword(s):  
Oxidation Process ◽  
Oxidation Stability ◽  
Development Trend ◽  
Electric Arc ◽  
Transformer Oil ◽  
Research Progress ◽  
Oil Oxidation ◽  
Electrochemical Test ◽  
The Development Trend

Under the actions of dissolved oxygen, temperature, electric field, electric arc, moisture, impurities and metal catalysts, transformer oil in operation will undergo oxidation and cracking, which may result in production of large quantities of peroxides, alcohols, aldehydes, ketones and acids. To improve the oxidation stability of oil, the antioxidants should be added into the transformer oil before operation. This paper mainly introduced the oxidation process of transformer oil, the harm of transformer oil oxidation and the method for the determination of the T501 antioxidants content in transformer oil. It also forecast the development trend of the electrochemical test in the determination of T501 antioxidants content.

Highly Efficient Photocatalytic Disinfection of Escherichia coli by Rose Bengal-Functionalized Graphene Oxide Nanosheets

2020 ◽  
Vol 20 (12) ◽  
pp. 7558-7568
Author(s):  
Fenping Chi ◽  
Pengpeng Chen ◽  
Changjie Mao
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Rose Bengal ◽  
Photoelectron Spectroscopy ◽  
Infrared Spectrometry ◽  
Ros Generation ◽  
Functionalized Graphene Oxide ◽  
E Coli ◽  
Transmission Electron ◽  
Sterilization Effect

Rose Bengal (RB) was used as a functional pigment and poly dimethyl diallyl ammonium chloride was used as a coupling agent to modify Graphene Oxide (GO) in order to enhance the light absorption and ROS generation of GO. GO, RB and the obtained RB-PDDA-GO were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrometry, thermogravimetric analysis, Raman spectroscopy, UV-visible spectrophotometry, and X-ray photoelectron spectroscopy. The oxidation of hydroquinone to p-benzoquinone was used to evaluate the oxidation ability. Three kinds of reactive oxygen species (O2·-, 1O2 and ·OH) produced by the materials under light irradiation were detected by the ESR method using TEMP (2,2,6,6-tetramethyl-4-piperidine) and DMPO (5,5-dimethyl-1-pyrroline-N-oxide) as capture agents. The results showed that RB-PDDA-GO produced more ROS under light than GO. Antibacterial experiments were carried out with E. coli as the target strain to detect the actual utility of ROS produced by the materials. The results showed that RB-PDDA-GO had a significant sterilization effect.

scholarly journals 3D-Flower-Like Copper Sulfide Nanoflake-Decorated Carbon Nanofragments-Modified Glassy Carbon Electrodes for Simultaneous Electrocatalytic Sensing of Co-existing Hydroquinone and Catechol

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2289 ◽  
Author(s):  
Lina Abdullah Alshahrani ◽  
Liqiong Miao ◽  
Yanyu Zhang ◽  
Shengming Cheng ◽  
Palanivel Sathishkumar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Glassy Carbon ◽  
Photoelectron Spectroscopy ◽  
Copper Sulfide ◽  
Environmental Pollutants ◽  
Differential Pulse ◽  
Glassy Carbon Electrodes ◽  
X Ray ◽  
Transmission Electron

A copper sulfide nanoflakes-decorated carbon nanofragments-modified glassy carbon electrode (CuS-CNF/GCE) was fabricated for the electrocatalytic differentiation and determination of hydroquinone (HQ) and catechol (CC). The physicochemical properties of the CuS-CNF were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy. The electrocatalytic determination of HQ and CC over the CuS-CNF/GCE was evaluated by cyclic voltammetry and differential pulse voltammetry. An excellent detection limit and sensitivity of the CuS-CNF/GCE are obtained (0.293 µM and 0.259 µM) with a sensitivity of 184 nA µM−1 cm−2 and 208 nA µM−1 cm−2 (S/N=3) for HQ and CC, respectively. In addition, the CuS-CNF/GCE shows a selective identification of HQ and CC over potential interfering metal ions (Zn2+, Na+, K+, NO3−, SO42−, Cl−) and organic compounds (ascorbic acid, glucose), and a satisfactory recovery is also obtained in the spiked water samples. These results suggest that the CuS-CNF/GCE can be used as an efficient electrochemical sensor for the simultaneous determination of co-existing environmental pollutants such as HQ and CC in water environments with high selectivity and acceptable reproducibility.

scholarly journals Selective Removal of Hemoglobin from Blood Using Hierarchical Copper Shells Anchored to Magnetic Nanoparticles

2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Youxun Liu ◽  
Yaokun Wang ◽  
Mingyang Yan ◽  
Juan Huang
Keyword(s):  
Electron Microscopy ◽  
Magnetic Nanoparticles ◽  
Human Blood ◽  
Photoelectron Spectroscopy ◽  
Infrared Spectrometry ◽  
Maximum Adsorption Capacity ◽  
Bovine Hemoglobin ◽  
One Pot ◽  
Transmission Electron ◽  
Pseudo Second Order

Hierarchical copper shells anchored on magnetic nanoparticles were designed and fabricated to selectively deplete hemoglobin from human blood by immobilized metal affinity chromatography. Briefly, CoFe2O4nanoparticles coated with polyacrylic acid were first synthesized by a one-pot solvothermal method. Hierarchical copper shells were then deposited by immobilizing Cu2+on nanoparticles and subsequently by reducing between the solid CoFe2O4@COOH and copper solution with NaBH4. The resulting nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. The particles were also tested against purified bovine hemoglobin over a range of pH, contact time, and initial protein concentration. Hemoglobin adsorption followed pseudo-second-order kinetics and reached equilibrium in 90 min. Isothermal data also fit the Langmuir model well, with calculated maximum adsorption capacity 666 mg g−1. Due to the high density of Cu2+on the shell, the nanoparticles efficiently and selectively deplete hemoglobin from human blood. Taken together, the results demonstrate that the particles with hierarchical copper shells effectively remove abundant, histidine-rich proteins, such as hemoglobin from human blood, and thereby minimize interference in diagnostic and other assays.

scholarly journals Characterization and Determination of Nanoparticles in Commercial Processed Foods

Foods ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2020
Author(s):  
Jin Yu ◽  
Ye-Rin Jeon ◽  
Ye-Hyun Kim ◽  
Eun-Been Jung ◽  
Soo-Jin Choi
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Constituent Particle ◽  
Particle Sizes ◽  
Processed Foods ◽  
Zeta Potentials ◽  
Transmission Electron ◽  
Different Characteristics ◽  
Acceleration Voltage

A wide variety of foods manufactured by nanotechnology are commercially available on the market and labeled as nanoproducts. However, it is challenging to determine the presence of nanoparticles (NPs) in complex food matrices and processed foods. In this study, top-down-approach-produced (TD)-NP products and nanobubble waters (NBWs) were chosen as representative powdered and liquid nanoproducts, respectively. The characterization and determination of NPs in TD-NP products and NBWs were carried out by measuring constituent particle sizes, hydrodynamic diameters, zeta potentials, and surface chemistry. The results show that most NBWs had different characteristics compared with those of conventional sparkling waters, but nanobubbles were unstable during storage. On the other hand, powdered TD-NP products were found to be highly aggregated, and the constituent particle sizes less than 100 nm were remarkably observed after dispersion compared with counterpart conventional bulk-sized products by scanning electron microscopy at low acceleration voltage and cryogenic transmission electron microscopy. The differences in chemical composition and chemical state between TD-NPs and their counterpart conventional bulk products were also found by X-ray photoelectron spectroscopy. These findings will provide basic information about the presence of NPs in nano-labeled products and be useful to understand and predict the potential toxicity of NPs applied to the food industry.

Enhanced information from biological materials through technological improvements in cryo-electron microscopy

1992 ◽  
Vol 50 (1) ◽  
pp. 788-789
Author(s):  
Marc J.C. de Jong ◽  
Wim M. Busing ◽  
Max T. Otten
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Biological Materials ◽  
Electron Crystallography ◽  
Cryo Electron Microscopy ◽  
Transmission Electron ◽  
The Many ◽  
Technological Improvements ◽  
Beam Damage

Biological materials damage rapidly in the electron beam, limiting the amount of information that can be obtained in the transmission electron microscope. The discovery that observation at cryo temperatures strongly reduces beam damage (in addition to making it unnecessaiy to use chemical fixatives, dehydration agents and stains, which introduce artefacts) has given an important step forward to preserving the ‘live’ situation and makes it possible to study the relation between function, chemical composition and morphology.Among the many cryo-applications, the most challenging is perhaps the determination of the atomic structure. Henderson and co-workers were able to determine the structure of the purple membrane by electron crystallography, providing an understanding of the membrane's working as a proton pump. As far as understood at present, the main stumbling block in achieving high resolution appears to be a random movement of atoms or molecules in the specimen within a fraction of a second after exposure to the electron beam, which destroys the highest-resolution detail sought.

Investigation of Polyoxometalate-(Poly)pyrrole Heterogeneous Nanostructures as Cathodes for Rechargeable Magnesium-Ion Batteries

2018 ◽  
Author(s):  
Hakeem K. Henry ◽  
Sang Bok Lee
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Active Material ◽  
Conductive Polymer ◽  
Current Collector ◽  
Constant Current ◽  
Anodized Aluminum ◽  
Transmission Electron ◽  
Pyrrole Monomer

The PMo<sub>12</sub>-PPy heterogeneous cathode was synthesized electrochemically. In doing so, the PMo<sub>12</sub> redox-active material was impregnated throughout the conductive polymer matrix of the poly(pyrrole) nanowires. All chemicals and reagents used were purchased from Sigma-Aldrich. Anodized aluminum oxide (AAO) purchased from Whatman served as the porous hard template for nanowire deposition. A thin layer of gold of approximately 200nm was sputtered onto the disordered side of the AAO membrane to serve as the current collector. Copper tape was connected to the sputtered gold for contact and the device was sealed in parafilm with heat with an exposed area of 0.32 cm<sup>2</sup> to serve as the electroactive area for deposition. All electrochemical synthesis and experiments were conducted using a Bio-Logic MPG2 potentiostat. The deposition was carried out using a 3-electrode beaker cell setup with a solution of acetonitrile containing 5mM and 14mM of the phosphomolybdic acid and pyrrole monomer, respectively. The synthesis was achieved using chronoamperometry to apply a constant voltage of 0.8V vs. Ag/AgCl (BASi) to oxidatively polymerize the pyrrole monomer to poly(pyrrole). To prevent the POM from chemically polymerizing the pyrrole, an injection method was used in which the pyrrole monomer was added to the POM solution only after the deposition voltage had already been applied. The deposition was well controlled by limiting the amount of charge transferred to 300mC. Following deposition, the AAO template was removed by soaking in 3M sodium hydroxide (NaOH) for 20 minutes and rinsed several times with water. After synthesis, all cathodes underwent electrochemical testing to determine their performance using cyclic voltammetry and constant current charge-discharge cycling in 0.1 M Mg(ClO<sub>4</sub>)<sub>2</sub>/PC electrolyte. The cathodes were further characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), and x-ray photoelectron spectroscopy (XPS).

scholarly journals Synthesis of Ce1−xPdxO2−δ Solid Solution in Molten Nitrate

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 640
Author(s):  
Hideaki Sasaki ◽  
Keisuke Sakamoto ◽  
Masami Mori ◽  
Tatsuaki Sakamoto
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Solid Solutions ◽  
Photoelectron Spectroscopy ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Ionic States

CeO2-based solid solutions in which Pd partially substitutes for Ce attract considerable attention, owing to their high catalytic performances. In this study, the solid solution (Ce1−xPdxO2−δ) with a high Pd content (x ~ 0.2) was synthesized through co-precipitation under oxidative conditions using molten nitrate, and its structure and thermal decomposition were examined. The characteristics of the solid solution, such as the change in a lattice constant, inhibition of sintering, and ionic states, were examined using X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM−EDS), transmission electron microscopy (TEM)−EDS, and X-ray photoelectron spectroscopy (XPS). The synthesis method proposed in this study appears suitable for the easy preparation of CeO2 solid solutions with a high Pd content.

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