Super-Stable, High-Quality Fe3O4 Dendron-Nanocrystals Dispersible in Both Organic and Aqueous Solutions

2005 ◽  
Vol 17 (11) ◽  
pp. 1429-1432 ◽  
Author(s):  
M. Kim ◽  
Y. Chen ◽  
Y. Liu ◽  
X. Peng
Keyword(s):  
Aqueous Solutions ◽  
High Quality

Analysis Of Chemical Heterogeneity And Purity Of Commercial Heparins

1981 ◽  
Author(s):  
R Hurst ◽  
A Lurie ◽  
J Settine ◽  
M Corum
Keyword(s):  
Aqueous Solutions ◽  
Sequential Extraction ◽  
Chemical Properties ◽  
Practical Method ◽  
Chemical Heterogeneity ◽  
Lower Sensitivity ◽  
High Quality ◽  
Equivalent Fractions ◽  
Molar Ratios ◽  
Heparin Fractions

The nature of chemical heterogeneity in commercial heparin was investigated, and a practical method of characterization and assay of pharmaceutical heparins was developed. One beef-lung (BL) and six hog-mucosal (HM) heparins were fractionated by sequential extraction of their hexadecyl- pyridinium complexes in 1-butanol by aqueous solutions containing successively increasing concentrations of NaCl. This system fractionates heparins larger than 10,000 daltons according to their anionic density. The fractions were characterized by molar ratios of carbohydrate constituents and by their anticoagulant potencies in the APTT test with human plasma. Galactosamine content and the amount of uronate extracted with less than 0.14 M NaCl provided a measure of non-heparin GAG and low-quality heparin. The molar ratios of carbohydrate constituents of equivalent fractions from different HM heparins were similar, and with the exception of one unbleached sample, had equivalent anticoagulant potencies which were linearly related to the square of the anionic density. The BL-heparin was clearly distinguishable from the HM-heparins in that its most abundant fractions were extracted at higher NaCl concentrations, and the systematic variation in anionic density seen with HM- heparins was not evident. The fractions were only about half as potent as the equivalent HM-heparin fractions.A simplified version of the extraction with a two-step partition fractionation was used to measure the percentages of non-heparin GAG and high-quality heparin respectively, and measurements of various molar ratios were used to both characterize the chemical properties of the heparin and its purity. Activation with silica in the APTT test yielded rectilinear semi logarithmic dilution plots whereas ellagic activation yielded curvilinear plots with lower sensitivity.

scholarly journals Nanocrystalline Ga2O3 films deposited by spray pyrolysis from water-based solutions on glass and TCO substrates

2019 ◽  
Vol 7 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Nina Winkler ◽  
Rachmat Adhi Wibowo ◽  
Wolfgang Kautek ◽  
Giovanni Ligorio ◽  
Emil J. W. List-Kratochvil ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Spray Pyrolysis ◽  
Process Parameters ◽  
Solution Composition ◽  
High Quality ◽  
Water Based ◽  
Spraying Process

High-quality Ga2O3 films are obtained by spray pyrolysis from aqueous solutions through optimization of the solution composition and the spraying process parameters.

Development of high quality activated carbon from biological sludge and its application for dyes removal from aqueous solutions

2019 ◽  
Vol 660 ◽  
pp. 277-287 ◽  
Author(s):  
Angélica F.M. Streit ◽  
Letícia N. Côrtes ◽  
Susanne P. Druzian ◽  
Marcelo Godinho ◽  
Gabriela C. Collazzo ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Aqueous Solutions ◽  
High Quality ◽  
Biological Sludge ◽  
Dyes Removal

scholarly journals Preparation of Flax Roving for Spinning in Electro-Chemical Activated Solutions

2019 ◽  
Vol 27 (6(138)) ◽  
pp. 34-38
Author(s):  
Pavel Hikolayevich Rudovsky ◽  
Mahammadali Nuraddin Nuriyev ◽  
Ilqar Saleh Recebov
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Hazardous Substances ◽  
High Quality ◽  
Wastewater Pollution ◽  
Treatment Procedures ◽  
Selection Of

A number of environmentally hazardous substances are used in the process of flax roving preparation for spinning. An alternative to them can be the use of electrochemical activated aqueous solutions. However, the metastability of such solutions requires time tracking of their properties’ relaxation. This article pre-sents experimental data on the relaxation of relevant solutions that can be used for a well-founded selection of flax roving treatment procedures to ensure a re-quired quality of flax yarn. It has been experimentally proven that the use of ECA solutions for preparing rovings for spinning allows to obtain high quality yarn as well as significantly reduce wastewater pollution and improve the envi-ronmental situation in the places of their emissions.

scholarly journals Chemical-mechanical polishing of CdTe and based on its solid solutions single crystals using HNO3 + НІ + ethylene glycol iodine-emerging solutions

2019 ◽  
pp. 45-49
Author(s):  
Ye. Ye. Hvozdiyevskyi ◽  
R. O. Denysyuk ◽  
V. M. Tomashyk ◽  
G. P. Malanych ◽  
Z. F. Tomashyk Tomashyk ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Aqueous Solutions ◽  
Single Crystals ◽  
Solid Solutions ◽  
Chemical Mechanical Polishing ◽  
Etching Rate ◽  
Mechanical Polishing ◽  
Thin Layers ◽  
Metallographic Analysis ◽  
High Quality

The interaction of the CdTe and Zn0.04Cd0.96Te, Cd0.2Hg0.8Te solid solutions single crystals with the iodine-emerging etchings based on aqueous solutions of HNO3 + НІ + ethylene glycol has been investigated and etching compositions have been developed and optimized, as well as methods of their chemical treatment for the formation of high-quality surface. The dissolution of these semiconductor materials in the aqueous solutions of the (HNO3+HI+EG)/EG have been investigated and dependences “etchant composition – etching rate” with determining the regions of polishing and unpolishing solutions have been constructed. It was found that the semiconductors etching rate (chemical-mechanical polishing) decreases from 73.2 to 0.5 μm/min and the polishing features of the HNO3+HI+EG etching composition improve when the EG content is increasing. The minimum value of the etching rates is achieved when the saturation of the organic component is maximum (95 vol. %). The dependences of the chemical-mechanical polishing rate on the dilution of the base polishing etchant with ethylene glycol and the surface condition after polishing have investigated using metallographic analysis and atomic force microscopy. It was established that chemical-mechanical polishing of the CdTe and Zn0.04Cd0.96Te, Cd0.2Hg0.8Te solid solutions single crystals by the (HNO3+HI+EG)/EG solutions promote decreasing of the structural damages of the substrate and obtaining the high-quality polishing surface. It has been shown that etchant compositions of HNO3+HI+ EG with EG as a solvent completely meet the requirements for CMP etchants. Treatment of the Cd0.2Hg0.8Te crystal surfaces with new etchant mixtures allows to obtain ultra-smooth surfaces Ra = 1.5 nm. The polishing etchant compositions (HNO3+HI+EG)/EG and technological procedures of the chemical mechanical polishing for the disturbed layer elimination, controlled thinning of the plates up to reference dimension, as well as the thin layers removing and CdTe single crystals and Zn0.04Cd0.96Te, Cd0.2Hg0.8Te solid solutions finishing polishing have been optimized.

Some problems of objective-prism spectra classification

1966 ◽  
Vol 24 ◽  
pp. 51-52
Author(s):  
E. K. Kharadze ◽  
R. A. Bartaya
Keyword(s):  
Short Wave ◽  
High Quality ◽  
Stellar Spectra ◽  
Objective Prism

The unique 70-cm meniscus-type telescope of the Abastumani Astrophysical Observatory supplied with two objective prisms and the seeing conditions characteristic at Mount Kanobili (Abastumani) permit us to obtain stellar spectra of a high quality. No additional design to improve the “climate” immediately around the telescope itself is being applied. The dispersions and photographic magnitude limits are 160 and 660Å/mm, and 12–13, respectively. The short-wave end of spectra reaches 3500–3400Å.

Ultrathin frozen sections of yeast without aldehyde prefixation

1978 ◽  
Vol 36 (2) ◽  
pp. 58-59
Author(s):  
K. J. Böhm ◽  
a. E. Unger
Keyword(s):  
Aqueous Solutions ◽  
Biological Material ◽  
Yeast Cells ◽  
Frozen Sections ◽  
Good Preservation ◽  
Ultrathin Frozen Sections

During the last years it was shown that also by means of cryo-ultra-microtomy a good preservation of substructural details of biological material was possible. However the specimen generally was prefixed in these cases with aldehydes.Preparing ultrathin frozen sections of chemically non-prefixed material commonly was linked up to considerable technical and manual expense and the results were not always satisfying. Furthermore, it seems to be impossible to carry out cytochemical investigations by means of treating sections of unfixed biological material with aqueous solutions.We therefore tried to overcome these difficulties by preparing yeast cells (S. cerevisiae) in the following manner:

A non-cyanide method of electropolishing silver

1978 ◽  
Vol 36 (1) ◽  
pp. 146-147
Author(s):  
R. L. Lyles ◽  
S. J. Rothman ◽  
W. Jäger
Keyword(s):  
Electron Microscopy ◽  
Sulphuric Acid ◽  
Methyl Alcohol ◽  
Health Hazards ◽  
Silver Alloy ◽  
High Quality ◽  
Silver Alloys ◽  
Free Sample ◽  
Specimen Quality ◽  
Standard Techniques

Standard techniques of electropolishing silver and silver alloys for electron microscopy in most instances have relied on various CN recipes. These methods have been characteristically unsatisfactory due to difficulties in obtaining large electron transparent areas, reproducible results, adequate solution lifetimes, and contamination free sample surfaces. In addition, there are the inherent health hazards associated with the use of CN solutions. Various attempts to develop noncyanic methods of electropolishing specimens for electron microscopy have not been successful in that the specimen quality problems encountered with the CN solutions have also existed in the previously proposed non-cyanic methods.The technique we describe allows us to jet polish high quality silver and silver alloy microscope specimens with consistant reproducibility and without the use of CN salts.The solution is similar to that suggested by Myschoyaev et al. It consists, in order of mixing, 115ml glacial actic acid (CH3CO2H, specific wt 1.04 g/ml), 43ml sulphuric acid (H2SO4, specific wt. g/ml), 350 ml anhydrous methyl alcohol, and 77 g thiourea (NH2CSNH2).

A High Resolution Scanning Microscope

1968 ◽  
Vol 26 ◽  
pp. 356-357
Author(s):  
A. V. Crewe ◽  
J. Wall ◽  
L. M. Welter
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Spherical Aberration ◽  
Focal Length ◽  
Spot Size ◽  
Emission Source ◽  
Field Of View ◽  
Scanning Microscope ◽  
Magnetic Lens ◽  
High Quality

A scanning microscope using a field emission source has been described elsewhere. This microscope has now been improved by replacing the single magnetic lens with a high quality lens of the type described by Ruska. This lens has a focal length of 1 mm and a spherical aberration coefficient of 0.5 mm. The final spot size, and therefore the microscope resolution, is limited by the aberration of this lens to about 6 Å.The lens has been constructed very carefully, maintaining a tolerance of + 1 μ on all critical surfaces. The gun is prealigned on the lens to form a compact unit. The only mechanical adjustments are those which control the specimen and the tip positions. The microscope can be used in two modes. With the lens off and the gun focused on the specimen, the resolution is 250 Å over an undistorted field of view of 2 mm. With the lens on,the resolution is 20 Å or better over a field of view of 40 microns. The magnification can be accurately varied by attenuating the raster current.

Quantitative defect studies in semiconductor TEM samples prepared by low angle ion milling

1995 ◽  
Vol 53 ◽  
pp. 512-513
Author(s):  
L. Mulestagno ◽  
J.C. Holzer ◽  
P. Fraundorf
Keyword(s):  
Sample Preparation ◽  
Milling Time ◽  
High Density ◽  
Low Density ◽  
Ion Milling ◽  
High Quality ◽  
Variable Angle ◽  
Major Disadvantage ◽  
Induced Defects

Due to the wealth of information, both analytical and structural that can be obtained from it TEM always has been a favorite tool for the analysis of process-induced defects in semiconductor wafers. The only major disadvantage has always been, that the volume under study in the TEM is relatively small, making it difficult to locate low density defects, and sample preparation is a somewhat lengthy procedure. This problem has been somewhat alleviated by the availability of efficient low angle milling.Using a PIPS® variable angle ion -mill, manufactured by Gatan, we have been consistently obtaining planar specimens with a high quality thin area in excess of 5 × 104 μm2 in about half an hour (milling time), which has made it possible to locate defects at lower densities, or, for defects of relatively high density, obtain information which is statistically more significant (table 1).

Sign in / Sign up

Export Citation Format

Share Document