Surface Modification and Preparation of High Purity Nanometer Magnesium Hydroxide Using Impinging Stream

2011 ◽  
Vol 675-677 ◽  
pp. 847-851
Author(s):  
Jian Hai Zhao ◽  
Yan Ping Lai
Keyword(s):  
Surface Modification ◽  
Magnesium Hydroxide ◽  
High Purity ◽  
X Ray Diffraction ◽  
Control Factors ◽  
Operation Conditions ◽  
Crystallization Method ◽  
Transmission Electron ◽  
Mean Size ◽  
The Mean

High purity nanometer magnesium hydroxide is produced by impinging stream reaction crystallization method using bischofite as feedstock. Effects of operation conditions on the impinging stream of Mg (OH)2 are reported and the control factors of purity are confirmed. The morphology of the powder was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Result shows that purity of Mg (OH)2 can reach 99% and the mean size of crystal is 13.5nm. Surface modification of nano-sized magnesium hydroxide using four surface modifiers such as sodium steatite, sodium laurylsulfonate, sodium oleate and sodium silicate were investigated in this paper. The modified magnesium hydroxide has smaller particle size, larger powder contact angle, slower sedimentation velocity, the less in-oil capacity than unmodified sample

THE SIZE CONTROL OF UNIFORM NANOCRYSTALLINE Si GRAINS BY CONSTRAINED GROWTH MODEL

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2751-2756 ◽  
Author(s):  
KUNJI CHEN ◽  
KAI CHEN ◽  
PEIGAO HAN ◽  
HECHENG ZOU ◽  
ZHONGYUAN MA ◽  
...  
Keyword(s):  
Size Control ◽  
Nanocrystalline Silicon ◽  
Annealing Conditions ◽  
Crystallization Method ◽  
Transmission Electron ◽  
Mean Size ◽  
Sublayer Thickness ◽  
The Mean ◽  
Size Controlled ◽  
Nanocrystalline Si

Size-controlled nanocrystalline silicon ( nc - Si ) has been prepared from a - SiN x / a - Si:H/a - SiN x ( 'a' standing for amorphous) sandwich structures by thermal annealing. Transmission electron microscope analyses show that the mean size and the grain size distribution (GSD) of the nc - Si are controlled by the annealing conditions and the a - Si sublayer thickness. Based on our theoretical model of constrained crystallization, we interpret the phenomena of the growth halt of nc - Si and higher crystallization temperature for the thinner a - Si sublayers. The experimental results show that constrained crystallization method is promising to achieve uniform and high density nc - Si array which can be used in the future nano-devices.

scholarly journals Модификация структурно-морфологических свойств германия в многослойной нанопериодической структуре Al-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-/Ge с промежуточными слоями Si при отжиге

2021 ◽  
Vol 55 (10) ◽  
pp. 882
Author(s):  
М.В. Байдакова ◽  
Н.А. Берт ◽  
В.Ю. Давыдов ◽  
А.В. Ершов ◽  
А.А. Левин ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Annealing Temperature ◽  
Electron Beam Evaporation ◽  
X Ray Diffraction ◽  
Bimodal Size Distribution ◽  
X Ray ◽  
Transmission Electron ◽  
Mean Size ◽  
The Mean

Multi-layered nanosized Al2O3/Ge/Si structures manufactured by electron-beam evaporation and annealed at a temperature within the range 700−900◦C are examined using transmission electron microscopy, Raman spectroscopy and X-ray diffraction techniques. The periodic structure with a good layer planarity is confirmed to retain after heat treatment up to 900◦C. At an annealing temperature above 700◦C, nanocrystallites with a bimodal size distribution start to form within initially amorphous Ge layers, the mean size of small crystallites being determined by Ge layer thickness and annealing temperature. An essential loss of Ge from multi-layered structure after 900oC anneal and development of Ge1−x Six solid solution with x up to 0.07 in the nanocrystallites is revealed.

scholarly journals Mudrock Microstructure: A Technique for Distinguishing between Deep-Water Fine-Grained Sediments

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 653
Author(s):  
Shereef Bankole ◽  
Dorrik Stow ◽  
Zeinab Smillie ◽  
Jim Buckman ◽  
Helen Lever
Keyword(s):  
Grain Size ◽  
Deep Water ◽  
Sedimentary Facies ◽  
X Ray Diffraction ◽  
Weak Current ◽  
Large Area ◽  
Fine Grained ◽  
Mean Size ◽  
The Mean ◽  
Water Facies

Distinguishing among deep-water sedimentary facies has been a difficult task. This is possibly due to the process continuum in deep water, in which sediments occur in complex associations. The lack of definite sedimentological features among the different facies between hemipelagites and contourites presented a great challenge. In this study, we present detailed mudrock characteristics of the three main deep-water facies based on sedimentological characteristics, laser diffraction granulometry, high-resolution, large area scanning electron microscopy (SEM), and the synchrotron X-ray diffraction technique. Our results show that the deep-water microstructure is mainly process controlled, and that the controlling factor on their grain size is much more complex than previously envisaged. Retarding current velocity, as well as the lower carrying capacity of the current, has an impact on the mean size and sorting for the contourite and turbidite facies, whereas hemipelagite grain size is impacted by the natural heterogeneity of the system caused by bioturbation. Based on the microfabric analysis, there is a disparate pattern observed among the sedimentary facies; turbidites are generally bedding parallel due to strong currents resulting in shear flow, contourites are random to semi-random as they are impacted by a weak current, while hemipelagites are random to oblique since they are impacted by bioturbation.

Lead inclusions in aluminium

1989 ◽  
Vol 157 ◽  
Author(s):  
E. Johnson ◽  
L. Gråbaek ◽  
J. Bohr ◽  
A. Johansen ◽  
L. Sarholt-Kristensen ◽  
...  
Keyword(s):  
Hysteresis Loop ◽  
Room Temperature ◽  
Noble Gas ◽  
Melting Transition ◽  
X Ray Diffraction ◽  
Free Surfaces ◽  
The Matrix ◽  
Mean Size ◽  
The Mean ◽  
Spontaneous Phase

ABSTRACTIon implantation at room temperature of lead into aluminium leads to spontaneous phase separation and formation of lead precipitates growing topotactically with the matrix. Unlike the highly pressurised (∼ 1–5 GPa) solid inclusions formed after noble gas implantations, the pressure in the lead precipitates is found to be less than 0.12 GPa.Recently we have observed the intriguing result that the lead inclusions in aluminium exhibit both superheating and supercooling [1]. In this paper we review and elaborate on these results. Small implantation-induced lead precipitates embedded in an aluminium matrix were studied by X-ray diffraction. The (111) Bragg peak originating from the lead crystals was followed during several temperature cycles, from room temperature to 678 K. The melting temperature for bulk lead is 601 K. In the first heating cycle we found a superheating of the lead precipitates of 67 K before melting occurred. During subsequent cooling a supercooling of 21 K below the solidification point of bulk lead was observed. In the subsequent heating cycles this hysteresis at the melting transition was reproducible. The full width of the hysteresis loop slowly decreased to 62 K, while the mean size of the inclusions gradually increased from 14.5 nm to 27 nm. The phenomena of superheating and supercooling are thus most pronounced for the small crystallites. The persistence of the hysteresis loop over successive heating cycles demonstrate that its cause is intrinsic in nature, and it is believed that the superheating originates from the lack of free surfaces of the lead inclusions.

scholarly journals MicroRNA Profiling of Exosomes Derived from Red Blood Cell Units: Implications in Transfusion-Related Immunomodulation

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Haobo Huang ◽  
Jinfeng Zhu ◽  
Liping Fan ◽  
Qiuyan Lin ◽  
Danhui Fu ◽  
...  
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Storage Time ◽  
Bioinformatic Analysis ◽  
Mirna Microarray ◽  
Qrt Pcr ◽  
Transmission Electron ◽  
Mean Size ◽  
The Mean ◽  
Polymerase Chain

Purpose. To elucidate the microRNAs existent in exosomes derived from stored red blood cell (RBC) unit and their potential function. Materials and Methods. Exosomes were isolated from the supernatant derived from stored RBC units by sequential centrifugation. Isolated exosomes were characterized by TEM (transmission electron microscopy), western blotting, and DLS (dynamic light scattering). MicroRNA (miRNA) microarray was performed to detect the expression of miRNAs in 3 exosome samples. Results revealed miRNAs that were simultaneously expressed in the 3 exosome samples and were previously reported to exist in mature RBCs. Functions and potential pathways of some detected miRNAs were illustrated by bioinformatic analysis. Validation of the top 3 abundant miRNAs was carried out by qRT-PCR (quantitative reverse transcription‐polymerase chain reaction). Results. TEM and DLS revealed the mean size of the exosomes (RBC-derived) as 64.08 nm. These exosomes exhibited higher abundance of short RNA than the long RNA. 78 miRNAs were simultaneously detected in 3 exosome samples and mature RBCs. Several biological processes might be impacted by these miRNAs, through their target gene(s) enriched in a particular signalling pathway. The top 3 (abundant) miRNAs detected were as follows: miR-125b-5p, miR-4454, and miR-451a. qRT-PCR revealed higher abundance of miR-451a than others. Only miR-4454 and miR-451a abundance tended to increase with increasing storage time. Conclusion. Exosomes derived from stored RBC units possessed multiple miRNAs and, hence, could serve various functions. The function of exosomes (RBC-derived) might be implemented partly by the predominantly enriched miR-451a.

Preparation and Characterization of Nanocrystalline Gadolinium Oxide Powders and Films

2020 ◽  
Vol 850 ◽  
pp. 267-272 ◽  
Author(s):  
Regina Burve ◽  
Vera Serga ◽  
Aija Krūmiņa ◽  
Raimons Poplausks
Keyword(s):  
Electron Microscopy ◽  
Single Phase ◽  
Gadolinium Oxide ◽  
X Ray Diffraction ◽  
Cubic Crystal ◽  
Glass Substrates ◽  
Oxide Powders ◽  
Transmission Electron ◽  
The Mean

Due to its magnetic, electrical, absorption, and emission properties, nanoscale gadolinium oxide is widely used in various fields. In this research, nanocrystalline Gd2O3 powders and films on glass substrates have been produced by the extraction-pyrolytic method. X-ray diffraction analysis revealed the formation of single phase Gd2O3 with cubic crystal structure and the mean crystallite size from 9 to 25 nm in all produced materials. The morphology of samples has been characterized by scanning electron microscopy and transmission electron microscopy.

Synthesis and Characterization of Mesoporous Silica Nanoparticles Embedded Gadolinium Oxide

2011 ◽  
Vol 306-307 ◽  
pp. 1275-1279 ◽  
Author(s):  
Ning Qi Luo ◽  
Zhan Yun Huang ◽  
Ping Luo ◽  
Yuan Zhi Shao ◽  
Di Hu Chen
Keyword(s):  
Mesoporous Silica ◽  
Self Assembly ◽  
Mesoporous Silica Nanoparticles ◽  
Sol Gel ◽  
Mesoporous Structure ◽  
Gadolinium Oxide ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Mean

We first synthesized gadolinium oxide (Gd2O3) by a modified “polyol” strategy and then embedded it into mesoporous silica by a simple self-assembly sol-gel reaction. Scanning electron microscope (SEM) results show that the samples have good sphericity and good dispersibility. The structure of mesoporous silica was characterized by transmission electron microscopy (TEM) and small-angle X-ray diffraction (SAXRD). Results show that the mesoporous structure has not been destroyed after gadolinium oxide imbedding. The ratio of gadolinium and silica was determined by the mean of energy dispersive spectroscopy (EDS).

INDIRECT MEASUREMENT OF Zn-DOPED In2S3 NANOFILMS' SPECIFIC HEAT CAPACITY

2008 ◽  
Vol 07 (04n05) ◽  
pp. 229-233 ◽  
Author(s):  
S. LAZZEZ ◽  
K. BOUBAKER BEN MAHMOUD ◽  
M. AMLOUK
Keyword(s):  
Heat Capacity ◽  
Electron Microscope ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Room Temperature ◽  
Thermal Analyses ◽  
Indirect Measurement ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Mean

ZnIn 2 S 4 nanofilms were grown on In 2 S 3 substrates. The band gap of ZnIn 2 S 4 barriers was approximately 2.8 eV at room temperature. The morphology and structure of the obtained nanofilms were already investigated via transmission electron microscope (TEM), scanning electron microscope (SEM) and X-ray diffraction analyses.1,2 In this paper, thermal analyses are performed via a photothermal technique, which has been used to indirectly evaluate the specific heat capacity of the obtained Zn -doped nanofilms. The yielded value for an optimal zinc-to-indium ratio, x (0.33), at the mean room temperature (T∞ = 301 K ), was Cs ≈ 411.5 J K -1 kg -1.

Preparation and Characterization of NiO Nanoparticles through Thermal Decomposition of Bis(glycinato)Nickel(II)dihydrate

2012 ◽  
Vol 601 ◽  
pp. 21-25
Author(s):  
Wei Yi Dan ◽  
Jian Fen Li ◽  
Xiang Chen Tu ◽  
Kui Le Jia
Keyword(s):  
Reaction Time ◽  
Fourier Transforms ◽  
Infrared Spectrometry ◽  
Nio Nanoparticles ◽  
X Ray Diffraction ◽  
Fine Crystal ◽  
Transmission Electron ◽  
Mean Size ◽  
Ft Ir

NiO nanoparticles were successfully prepared by decomposing the predecessor bis(glycinato)nickel(II)dihydrate in the presence of oleylamine and triphenylphosphine (TPP), and different approaches including Fourier transforms infrared spectrometry(FT-IR), X-ray diffraction(XRD) and transmission electron microscopy (TEM) were used to characterize the NiO nanoparticles. Meanwhile, the effects of TPP concentration and reaction time on the size and yield of NiO nanoparticles derived from precursors were thoroughly investigated in this paper. The analysis results indicated that the prepared NiO nanoparticles were found spherical in shape and demonstrated weak agglomeration. They had generally high purity and a fine crystal phase of cubic syngony. Furthermore, the effects of the TPP concentration and reaction time on the size and yield of NiO nanoparticles are very crucial, higher concentration of TPP would results in reduction of both the mean size and yield of NiO particles. However both yields and particles size of NiO nanoparticles continuously increased as increasing reaction time, after more than 60 minutes, the size and yield of NiO nanoparticles kept hardly change.

Synthesis and Characterization of Surface Protected Nanocrystalline Particles of Titania

1998 ◽  
Vol 519 ◽  
Author(s):  
E. Scolan ◽  
C. Sanchez
Keyword(s):  
X Ray Diffraction ◽  
Elastic Light Scattering ◽  
Titanium Butoxide ◽  
X Ray ◽  
Toluene Sulfonic Acid ◽  
Nanocrystalline Particles ◽  
Mean Size ◽  
The Mean ◽  
Cp Mas Nmr

AbstractMonodisperse non-aggregated nanoparticles of titania are obtained through hydrolysis at 60°C of titanium butoxide in the presence of acetylacetone and para-toluene sulfonic acid. After drying the resulting xerosols can be dispersed without aggregation in water-alcoholic or alcoholic solutions. The characterizations of the nanoparticles have been carried out by using quasi-elastic light scattering (QELS), 13C 1H in solution and X-ray diffraction, TEM, TG-DTA, 13C CP-MAS NMR in the solid state. The mean size of the anatase oxide core can be adjusted in the I to 5 nanometer range by a careful tuning of the synthetic conditions. The anatase particles are surrounded by acetylacetonato ligands, para-toluene sulfonate based species and water.

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