scholarly journals Зависимость температуры сублимации образующихся в пламенах сажевых частиц от их размеров и структуры

2022 ◽  
Vol 92 (1) ◽  
pp. 76
Author(s):  
Е.В. Гуренцов ◽  
А.В. Дракон ◽  
А.В. Еремин ◽  
Р.Н. Колотушкин ◽  
Е.Ю. Михеева
Keyword(s):  
Average Particle Size ◽  
Nanosecond Laser Pulse ◽  
Nanosecond Laser ◽  
Average Particle ◽  
Physical Analysis ◽  
Sublimation Temperature ◽  
Soot Particles ◽  
Significant Difference ◽  
Primary Particles ◽  
Average Size

In this paper, the dependence of the sublimation temperature of soot particles synthesized during the combustion of various hydrocarbons, depending on their size and structure, is obtained. The experimental approach is based on the analysis of the thermal radiation of particles heated to the sublimation temperature by a nanosecond laser pulse. The sublimation temperature of soot particles was measured using the two-color pyrometry method. In this paper, it is proposed to use the average size of primary particles to compare data in different flames. It is established, that the sublimation temperature of soot particles depends mainly on the stage of their formation, which is characterized by an increase in average size. It is shown, that with an increase in the average particle size from 12 to 23 nm, their sublimation temperature increases significantly from 2700 to 4500 K. This reflects a significant difference in the thermodynamic and optical properties of the so-called "young" and "mature" soot particles, which must be taken into account when developing methods of soot diagnostics and in the thermo-physical analysis of combustion and pyrolysis processes with the formation of soot.

scholarly journals Effect of the polymeric coating over Fe3O4 particles used for magnetic separation

2010 ◽  
Vol 8 (5) ◽  
pp. 1041-1046 ◽  
Author(s):  
Raúl Reza ◽  
Carlos Martínez Pérez ◽  
Claudia Rodríguez González ◽  
Humberto Romero ◽  
Perla García Casillas
Keyword(s):  
Particle Size ◽  
Magnetite Nanoparticles ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Polymeric Coating ◽  
Average Particle ◽  
Synthesis Conditions ◽  
Aging Conditions ◽  
Magnetite Particles ◽  
Average Size

AbstractIn this work, the synthesis of magnetite nanoparticles by two variant chemical coprecipitation methods that involve reflux and aging conditions was investigated. The influence of the synthesis conditions on particle size, morphology, magnetic properties and protein adsorption were studied. The synthesized magnetite nanoparticles showed a spherical shape with an average particle size directly influenced by the synthesis technique. Particles of average size 27 nm and 200 nm were obtained. When the coprecipitation method was used without reflux and aging, the smallest particles were obtained. Magnetite nanoparticles obtained from both methods exhibited a superparamagnetic behavior and their saturation magnetization was particle size dependent. Values of 67 and 78 emu g−1 were obtained for the 27 nm and 200 nm magnetite particles, respectively. The nanoparticles were coated with silica, aminosilane, and silica-aminosilane shell. The influence of the coating on protein absorption was studied using Bovine Serum Albumin (BSA) protein.

Lead Free Paste with under 3um Solder Particles for Fine Pitch C4 bumping and pre-coating solder applications

2013 ◽  
Vol 2013 (DPC) ◽  
pp. 000862-000889
Author(s):  
Hironori Uno ◽  
Masayuki Ishikawa ◽  
Akihiro Masuda ◽  
Hiroki Muraoka ◽  
Kanji Kuba
Keyword(s):  
Chemical Reduction ◽  
Average Particle Size ◽  
Average Particle ◽  
Solder Paste ◽  
Chemical Reduction Method ◽  
Property Evaluation ◽  
Fine Pitch ◽  
Solder Bumps ◽  
Size Of Particles ◽  
Average Size

The work to be detailed in this paper is our development of 96.5mass%Sn-3.0mass%Ag-0.5mass%Cu fine solder particles with an average particle size of under 3um (D50), using a chemical reduction method. An evaluation was conducted on the properties of the particles. The average size of particles appeared to be under 3um with a higher yield compared to particles using the conventional gas atomization method. The melting temperature of fine solder particles using this method was its eutectic temperature, which is same as using the gas–atomized particles. 120um pitch solder bumps from the solder paste using the above mentioned fine solder particles were created on the substrate. As a result of property evaluation, it was turned out that the solder paste created a superior printing shape and coplanarity compared to the conventional paste with gas-atomized particles. In order to investigate the superior printing property generated by the paste with fine solder particles, the rheology of the paste was evaluated.It was verified that the anisotropic shape of particles has contributed to prevent the printed paste from slumping, which has resulted in the improvement of printed shape. It also shows that the filling characteristic of the paste was improved by the smaller particles and the better coplanarity was observed. The importance of finer solder particles for finer pitch assembly will be presented.

Preparation of Cr2O3 Nanoparticles via Hydrothermal Reduction of CH3OH

2012 ◽  
Vol 463-464 ◽  
pp. 760-763
Author(s):  
Zhen Zhao Pei ◽  
Hong Bin Xu ◽  
Yi Zhang
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Average Particle Size ◽  
Average Particle ◽  
Calcination Temperatures ◽  
Cr2o3 Nanoparticles ◽  
Average Size ◽  
Hydrothermal Reduction ◽  
Scanning Electron

Nanoparticles of Cr2O3 were successfully obtained via hydrothermal reduction of CH3OH. The oxidant and chromium source was CrO3. The process needs no stirrer or surfactant and the CrO3 concentration was 0.83mol/L. The obtained products were loosely agglomerated Cr2O3 nanoparticles with the average size of 29 to 79 nm. Influences of reactant ratios and calcination temperatures on the specific surface area and average particle size were discussed. And the morphology of nanoparticles was investigated by use of field-emission scanning electron microscope.

FeCl2–CaCl2 melt volumetric reduction by calcium dissolved in calcium chloride

2018 ◽  
pp. 4-10
Author(s):  
V. V. Polyakov ◽  
A. V. Babin ◽  
V. A. Lebedev
Keyword(s):  
Iron Powder ◽  
Average Particle Size ◽  
Average Particle ◽  
Ultrasonic Dispersion ◽  
X Ray ◽  
Reduction Of Iron ◽  
Fine Iron ◽  
Three Stages ◽  
Average Size ◽  
Temperature Aging

The purpose of this study is to obtain highly dispersed powder suitable for spheroidization for further application in additive technologies. Volumetric reduction of the FeCl2–CaCl2melt by calcium dissolved in CaCl2produced fine iron powder. The process consisted of three stages: preparation of melts containing FeCl2and Ca, their mixing and high-temperature aging at 800 °C for 1 hour. At the end of the process the frozen melt was divided into upper and bottom parts. The product from the upper part had a specific surface area of 7,60 m2/g, and for the lower part it was 5,38 m2/g, Average particle size was 157 μm for the former and 124 μm for the latter. After ultrasonic dispersion, it was reduced to 26 μm and 71 μm, respectively. Quantitative X-ray phase analysis showed that the main phase of powder is metallic iron (more than 97 wt.%). Therefore, research originality is the use of volumetric, intensive reduction of iron from chloride melts by calcium dissolved in its chloride. The uniqueness of the study consists in the product obtained, i.e. the main part of reduced iron is in the melt volume as linear aggregates 40 to 600 μm in length, 10 to 50 μm in diameter that are easily broken by ultrasonic dispersion into individual crystals with an average size of 26 μm. The results of the study demonstrated the feasibility of calcium-thermal production of fine iron powder.

Green Route Synthesis of MgO Nanoparticles Using Murraya Koenigii Leaf Extract: An Efficient Photo Catalyst for Malachite Green

2018 ◽  
Vol 24 (8) ◽  
pp. 5801-5804
Author(s):  
K. N. Shravana Kumara ◽  
H. P Nagaswarupa ◽  
K. R. Vishnu Mahesh ◽  
M Mylarappa ◽  
S. C Prashantha ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Average Particle Size ◽  
Diffraction Method ◽  
Combustion Method ◽  
Average Particle ◽  
Murraya Koenigii ◽  
Solution Combustion ◽  
Efficient Catalyst ◽  
Mgo Nanoparticles ◽  
Average Size

The objective of this work is mainly focused on green synthesis and characterization of MgO nanoparticles by low temperature solution combustion method. The Murraya koenigii (Curry leaves) was used as a reducing agent (as fuel). The average size and crystallinity of nano MgO particles are analyzed by X-ray Diffraction method (PXRD) and accurate morphology was studied using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). From XRD, shows that average particle size of MgO is 40 nm. The synthesized MgO particles used as an efficient catalyst shows rapid color removal and reduction in the concentration of dyes.

Synthesis of Nano-Sized Barium Titanate Powder by Rotary-Hydrothermal Process

2009 ◽  
Vol 421-422 ◽  
pp. 269-272
Author(s):  
Takashi Kubo ◽  
Masayuki Hogiri ◽  
Hiroshi Kagata ◽  
Atsushi Nakahira
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Hydrothermal Process ◽  
Water System ◽  
Starting Material ◽  
Average Particle ◽  
Rotary Speed ◽  
Average Size ◽  
Faceted Particles

Nano-sized BaTiO3 powders with narrow size distribution and the high tetragonality were attempted to synthesize by the rotary-hydrothermal process in water system, using two kinds of commercial anatase-type TiO2 (ST21/ST01) with different particle size and Ba(OH)2. The rotary-hydrothermal syntheses were done with the rotary-speed of 20 revolutions per minute at 523 K for 24 h. Highly- and mono-dispersed BaTiO3 powders were successfully synthesized by applying the rotary-hydrothermal process. For rotary-hydrothermal synthesis, it was found that the average size, tetragonality, and quality of the BaTiO3 particle strongly depended on the particle size of the starting material. In the case of using ST01 as a starting material, BaTiO3 nano-powders mainly composed of coarse-faceted particles (average particle size = ca.100 nm) with the tetragonal phase and very little lattice defects were successfully synthesized.

Preparation and Characterization of Gold Nanoparticles in the Presence of Citrate and Soybean Seed Extract in an Acidic Conditions

Drug Research ◽  
2017 ◽  
Vol 67 (05) ◽  
pp. 266-270 ◽  
Author(s):  
Ebrahim Izadi ◽  
Ali Rasooli ◽  
Abolfazl Akbarzadeh ◽  
Soodabeh Davaran
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Size Distribution ◽  
Average Particle Size ◽  
Soybean Seed ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Soybean Extract ◽  
Average Size

AbstractThrough the present study, an eco-friendly method was used to synthesize the gold nanoparticles (GNPs) by using the sodium citrate and extract of the soybean seed as reducing the agents at PH 3. X-Ray diffraction (XRD) method was used to evaluate the crystal structure of as-synthesized NPs and it’s revealed that this method leads to well crystallized GNPs. In order to determine the particle size and their distribution, field emission scanning microscopy (FE-SEM) and dynamic light scattering (DLS) were used. The results showed that, the average particle size distribution of synthesized GNPs in solutions containing of the soybean extract and 1% citrate at PH 3 is about 109.6 and 140.9 nm, respectively. Also, we find that the average size of GNPs is 40 and 33 nm from solutions of citrate and soybean extract, respectively. It was concluded that using the extract of soybean seeds as reducing agent can lead to GNPs with small size and narrow size distribution.

scholarly journals STUDYING MORPHOLOGY OF SUSPENSIONS BY THE METHOD OPTICAL SPECTROSCOPY

2020 ◽  
pp. 54-62
Author(s):  
Алена Игорьевна Маркова ◽  
Максим Вадимович Ярусов ◽  
Светлана Дмитриевна Хижняк ◽  
Павел Михайлович Пахомов
Keyword(s):  
Optical Spectroscopy ◽  
Spectroscopic Method ◽  
Average Particle Size ◽  
Filler Concentration ◽  
Average Particle ◽  
Uv Visible ◽  
Microscopy Data ◽  
Average Size ◽  
Radiation Passing ◽  
Good Agreement

Методом оптической спектроскопии (УФ, видимая и ИК области спектра) исследованы две суспензии: вазелиновое масло (ВМ) наполненное слюдой и BaSO различной концентрации. Разработанный метод основан на анализе рассеивающей компоненты электромагнитного излучения, проходящего через образец, позволяющий определить средний размер и распределение рассеивающих частиц по размерам. Установлено, что с увеличением концентрации наполнителя частицы агрегируют, вследствие чего средний размер частиц увеличивается. Результаты, полученные спектроскопическим методом, хорошо согласуются с данными оптической микроскопии. Two suspensions were studied by optical spectroscopy (UV, visible, and IR): vaseline oil (VM) filled with mica and BaSO of different concentrations. The developed method is based on the analysis of the scattering component of electromagnetic radiation passing through the sample, which makes it possible to determine the average size and size distribution of scattering particles. It was found that with increasing filler concentration, the particles aggregate, resulting in an increase in the average particle size. The results obtained by the spectroscopic method are in good agreement with the optical microscopy data.

TEM measurement of surface area of automotive catalysts

1994 ◽  
Vol 52 ◽  
pp. 776-777
Author(s):  
M. H. Yao ◽  
D. R. Liu ◽  
R. J. Baird ◽  
R. K. Usmen ◽  
R. W. McCabe
Keyword(s):  
Electron Microscopy ◽  
Surface Area ◽  
Average Particle Size ◽  
Weighted Average ◽  
Average Particle ◽  
Automotive Catalysts ◽  
Surface Areas ◽  
Measuring Surface ◽  
Major Factors ◽  
Average Size

The specific surface area of supported noble metal particles in an automotive catalyst is defined as the exposed surface area per unit mass of these particles. It is of great importance to know this parameter, since this is one of the major factors that determine the effectiveness of the catalyst. Commonly used methods for characterizing catalysts, such as X-ray diffraction and TEM, do not directly provide a measure of surface area, but, instead, provide a measure of the “average size” of supported particles. Moreover, the “average sizes” obtained from different experimental techniques are often not comparable. Furthermore, many previous electron microscopy catalyst studies measured only simple average particle size, and no detailed procedure for measuring area-weighted average size or surface area appear to have been reported.In the current study, a procedure for measuring surface area of supported particles by transmission electron microscopy(TEM) was developed, and applied to measure surface areas of various production three-way automotive catalysts.

Therapeutic Effects of Paclitaxel Loaded Polyethylene Glycol-Polylactic Acid-Glycolic Acid Copolymer Nanoparticles on Pancreatic Cancer in Rats

2020 ◽  
Vol 20 (12) ◽  
pp. 7271-7275
Author(s):  
Yu Fu ◽  
Ludong Tan ◽  
Lingyu Meng ◽  
Xuexue Lei
Keyword(s):  
Pancreatic Cancer ◽  
Flow Cytometry ◽  
Particle Size ◽  
Drug Loading ◽  
Average Particle Size ◽  
Pancreatic Cancer Cell Line ◽  
Human Pancreatic Cancer ◽  
Average Particle ◽  
Therapeutic Effects ◽  
Significant Difference

To establish a simple and safe method for the preparation of paclitaxel PEG-PLGA nanoparticles emulsified in tpgs (PTX-pegpllga-np), for high drug loading; and to study its effect on proliferation and apoptosis of human pancreatic cancer cell line MIAPACA-2. PTX-PEG-PLGA-NP was prepared by one-step precipitation, using tpgs as emulsifier. The drug loading and particle size were used as an index to optimize the formulation, and the physical and chemical properties such as in vitro release and stability were characterized. The uptake of fluorescein coumarin 6 (C6) loaded PEG-PLGA-NP by MIAPACA-2 cells was observed by fluorescence microscope, and the growth and apoptosis of MIAPACA-2 cells after PTX-PEG-PLGA-NP were detected by MTT and flow cytometry respectively. The entrapment efficiency of the nanoparticles was 90.26%, the drug loading was 10.13%, the average particle size was 92.3±3.1 nm, and the zeta potential was 10.48±1.54 mV. The cumulative releases of nano preparation and general preparation (Taxol injection) in four hours were 25.9% and 98.5%, respectively; and the former had a strong sustained-release effect. The results of cell uptake experiments showed that the uptake of c6-PEG-PLGA-NP by MIAPACA-2 cells increased gradually with time. MTT results showed that PTX-PEG-PLGA-NP had no significant difference in the inhibition rate of MIAPACA-2 cells compared with PTX group. Flow cytometry showed that PTX-PEG-PLGAnp was superior better than PTX in inducing apoptosis in MIAPACA-2 cells. The tpgs emulsification method is simple and environment-friendly. The paclitaxel loaded nanoparticles prepared through the optimization of the formulation have large drug loading capacity and uniform particle size, which can target the pancreatic cancer MIAPACA-2 cells, and do not weaken its ability to inhibit the growth of MIAPACA-2 cells. The nanoparticles also induce apoptosis in cancer MIAPACA-2 cells, and could be used for further clinical treatment of pancreatic cancer.

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