scholarly journals Исследование состава остаточного газа в вакуумной системе циклотрона ФТИ им. А.Ф. Иоффе

2019 ◽  
Vol 45 (16) ◽  
pp. 30
Author(s):  
Н.Н. Аруев ◽  
М.А. Козловский ◽  
М.Ф. Кудояров ◽  
М.Я. Патрова ◽  
П.А. Романов ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Vacuum System ◽  
Water Molecules ◽  
Experimental Conditions ◽  
Ion Guide ◽  
Compact Size ◽  
Gas Molecules ◽  
Residual Gas ◽  
Irradiation Chamber ◽  
Ioffe Institute

4. Using the FT-200 compact-size time-of-flight mass spectrometer developed at the Ioffe Institute, the mass spectra of the residual gas molecules in the vacuum system of the Ioffe Institute cyclotron have been obtained under various experimental conditions. The measurements were carried out in the cyclotron vacuum chamber and the end part of the ion guide near the sample irradiation chamber. It was found that the main contribution to the residual gas composition in the cyclotron chamber is made by the molecules of pump oil used (up to 82%) and water molecules (up to 15-17%), and in the ion guide near the irradiation chamber with a polymer film - water molecules (up to 63%). The data obtained are the basis for the modernization of the Ioffe cyclotron complex.

High-resolution mass spectra of the residual gas in a metallic vacuum system

2006 ◽  
Vol 51 (1) ◽  
pp. 100-111 ◽  
Author(s):  
G. S. Anufriev ◽  
B. S. Boltenkov ◽  
A. I. Ryabinkov
Keyword(s):  
High Resolution ◽  
Mass Spectra ◽  
Vacuum System ◽  
High Resolution Mass ◽  
Residual Gas ◽  
Resolution Mass

Recent Progress In High-Resolution Shadowing For Biological Transmission Electron Microscopy

1990 ◽  
Vol 48 (1) ◽  
pp. 510-511 ◽  
Author(s):  
Heinz Gross ◽  
Katarina Krusche ◽  
Peter Tittmann
Keyword(s):  
Heavy Metal ◽  
High Resolution ◽  
Freeze Drying ◽  
Atmospheric Conditions ◽  
Vacuum Equipment ◽  
Transmission Electron ◽  
Gas Atmosphere ◽  
Gas Molecules ◽  
Residual Gas ◽  
Backing Layer

Freeze-drying followed by heavy metal shadowing is a long established and straight forward approach to routinely study the structure of dehydrated macromolecules. Very thin specimens such as isolated membranes or single macromolecules are directly adsorbed on C-coated grids. After rapid freezing the grids are transferred into a suitable vacuum equipment for freeze-drying and heavy metal shadowing.To improve the resolution power of shadowing films we introduced shadowing at very low specimen temperature (−250°C). To routinely do that without the danger of contamination we developed in collaboration with Balzers an UHV (p≤10-9 mbar) machine (BAF500K, Fig.2). It should be mentioned here that at −250°C the specimen surface acts as effective cryopump for practically all impinging residual gas molecules from the residual gas atmosphere.Common high resolution shadowing films (Pt/C, Ta/W) have to be protected from alterations due to air contact by a relatively thick C-backing layer, when transferred via atmospheric conditions into the TEM. Such an additional C-coat contributes disturbingly to the contrast at high resolution.

Intercalation Processes in Cobalt Substituted Nickel Oxyhydroxides

1990 ◽  
Vol 210 ◽  
Author(s):  
Claude Delmas
Keyword(s):  
Ir Spectroscopy ◽  
Mechanical Treatment ◽  
Positive Charge ◽  
Van Der Waals ◽  
The Other ◽  
Hydrolysis Reaction ◽  
Water Molecules ◽  
Layered Oxides ◽  
Experimental Conditions ◽  
Cobalt Ions

AbstractChimie douce reactions (hydrolysis and reduction) from layered oxides : NaNiO2, NaxCoO2 and NaNil-xCoxO2 lead to numerous oxyhydroxides and hydroxides which differ by the composition of the intersheet space.According to the experimental conditions of the hydrolysis reaction, the oxyhydroxides can be unhydrated or intercalated with one or two layers of water molecules. From the most hydrated phases, the other ones can be obtained by chemical, thermal and even mechanical treatment.The reduction of Co-substituted nickel oxyhydroxides leads to hydroxides in which nickel and cobalt ions are respectively divalent and trivalent. In order to compensate the excess of positive charge in the (Ni, Co)O2 sheet, anions (OH-, CO32-, SO42-, NO3-) are inserted in the Van der Waals gap.For the highest anion amounts, well ordered α*-type materials are obtained. Water molecules are simultaneously inserted in the interslab space. Their structure is strongly related to the hydrotalcite one. When the amouit of anions in the intersheet space is not sufficient, interstratified materials are obtained. In this case the (Ni,Co)(OH)2 slabs are separated by a layer of CO32- anions and water molecules (α*-type) or by an empty Van der Waals gap (β(II)-type). The amount of α*-type planes in the structure increases with the cobalt amount. All these materials have been characterized by IR spectroscopy which allows to detect the existence of two types of O-H bonds (free in α*-type plane or hydrogen bonded in ²(II)-type plane).

scholarly journals MMHub, a database for the mulberry metabolome

Database ◽  
2020 ◽  
Vol 2020 ◽  
Author(s):  
Dong Li ◽  
Bi Ma ◽  
Xiaofei Xu ◽  
Guo Chen ◽  
Tian Li ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Chemical Compounds ◽  
Bioactive Metabolites ◽  
Molecular Formula ◽  
Experimental Conditions ◽  
Chemical Structures ◽  
Pubchem Compound ◽  
Specific Distribution ◽  
Small Chemical ◽  
Metabolome Data

Abstract Mulberry is an important economic crop plant and traditional medicine. It contains a huge array of bioactive metabolites such as flavonoids, amino acids, alkaloids and vitamins. Consequently, mulberry has received increasing attention in recent years. MMHub (version 1.0) is the first open public repository of mass spectra of small chemical compounds (<1000 Da) in mulberry leaves. The database contains 936 electrospray ionization tandem mass spectrometry (ESI-MS2) data and lists the specific distribution of compounds in 91 mulberry resources with two biological duplicates. ESI-MS2 data were obtained under non-standardized and independent experimental conditions. In total, 124 metabolites were identified or tentatively annotated and details of 90 metabolites with associated chemical structures have been deposited in the database. Supporting information such as PubChem compound information, molecular formula and metabolite classification are also provided in the MS2 spectral tag library. The MMHub provides important and comprehensive metabolome data for scientists working with mulberry. This information will be useful for the screening of quality resources and specific metabolites of mulberry. Database URL: https://biodb.swu.edu.cn/mmdb/

Development of a Field Emission VP-SEM and Some Initial Applications

2001 ◽  
Vol 7 (S2) ◽  
pp. 882-883
Author(s):  
Masako Nishimura ◽  
Sukehiro Itoh ◽  
Steve Joens
Keyword(s):  
Field Emission ◽  
Chamber Pressure ◽  
Variable Pressure ◽  
Natural State ◽  
Backscattered Electrons ◽  
Pumping System ◽  
Multi Stage ◽  
Gas Molecules ◽  
Residual Gas ◽  
Differential Pumping

The use of variable pressure SEMs (VP-SEMs) is increasing in various fields of science and industry, allowing microscopy in a variable pressure environment of 1 ∼ 270 Pa utilizing backscattered electrons for imaging. The VP-SEM allows microscopy of insulated samples without the need for sample preparation. Charging artifacts can be minimized as well. When the VP-SEM is operated with a cooling stage, which allows cooling of samples at −20° and above, vaporization of water from samples is reduced. This permits microscopy of wet samples at close to the natural state for extended periods of time.Poor S/N ratio and deterioration of resolution, both of which are due to collisions among residual gas molecules and primary/backscattered electrons, have limited the performance of VP-SEMs. For resolving these limitations, we have completed the development of a new field emission VP-SEM which operates with a stable Schottky field emission source, a new environmental secondary electron detector (ESED), and a multi-stage differential pumping system. Fig. 1 shows a sectional view of the column with the differential pumping system. This design allows stable gun vacuum conditions with variable specimen chamber pressure 10 through 3,000 Pa, permitting a pressure difference from the gun by 1011 Pa without problems.

scholarly journals Methane-induced haemolysis of human erythrocytes

1995 ◽  
Vol 307 (2) ◽  
pp. 433-438 ◽  
Author(s):  
H Batliwala ◽  
T Somasundaram ◽  
E E Uzgiris ◽  
L Makowski
Keyword(s):  
Diffusion Rate ◽  
Human Erythrocytes ◽  
Experimental Conditions ◽  
Detergent Concentration ◽  
Partial Pressures ◽  
Temperature Diffusion ◽  
Wide Range ◽  
Gas Molecules ◽  
High Concentrations ◽  
Cell Leakage

Human erythrocytes were exposed to high concentrations of methane and nitrogen through the application of elevated partial pressures of these gas molecules. Cell leakage (haemolysis) was measured for cells exposed to these gases under a wide range of experimental conditions. Application of methane produces haemolysis at pressures far below the hydrostatic pressures known to disrupt membrane or protein structure. The effects of changes in buffer, temperature, diffusion rate and detergents were studied. Methane acts co-operatively with detergents to produce haemolysis at much lower detergent concentration than is required in the absence of methane or in the presence of nitrogen. At sufficiently high concentrations of methane, all cells are haemolysed. Increased temperature enhances the effect. Methane produces 50% haemolysis at a concentration of about 0.33 M compared with about 7.5 M methanol required for the same degree of haemolysis.

scholarly journals Prediction Modeling and Analysis of Knocking Combustion using an Improved 0D RGF Model and Supervised Deep Learning

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 844 ◽  
Author(s):  
Seokwon Cho ◽  
Jihwan Park ◽  
Chiheon Song ◽  
Sechul Oh ◽  
Sangyul Lee ◽  
...  
Keyword(s):  
Deep Learning ◽  
System Analysis ◽  
Combustion Engine ◽  
Cylinder Pressure ◽  
Estimation Model ◽  
Experimental Conditions ◽  
Modeling And Analysis ◽  
Residual Gas Fraction ◽  
Residual Gas ◽  
The Individual

The knock phenomenon is one of the major hindrances for enhancing the thermal efficiency in spark-ignited engines. Due to the stochastic behavior of knocking combustion, analytical cycle studies are required. However, there are many problems to be addressed with regard to the individual cycle analysis of in-cylinder pressure data. This study thus proposes novel, comprehensive and efficient methodologies for evaluating the knocking combustion in the internal combustion engine. The proposed methodologies include a filtering method for the in-cylinder pressure, the determination of the knock onset, and the calculation of the residual gas fraction. Consequently, a smart knock onset model with high accuracy could be developed using a supervised deep learning that was not available in the past. Moreover, an improved zero-dimensional (0D) estimation model for the residual gas fraction was developed to obtain better accuracy for closed system analysis. Finally, based on a cyclic analysis, a knock prediction model is suggested; the model uses 0D ignition delay correlation under various experimental conditions including aggressive cam phase shifting by a dual variable valve timing (VVT) system. Using the proposed analysis method, insight into stochastic knocking combustion can be obtained, and a faster combustion speed can lead to a higher knock intensity in a steady-state operation.

Residual Gas Phase Contamination of Al-Cu Alloy Films and its Effect on Electromigration Behavior

1996 ◽  
Vol 428 ◽  
Author(s):  
Imran Hashim ◽  
Ivo J. Raaijmakers ◽  
Glen Adler ◽  
Ardy Sidhwa ◽  
Sudhir Chopra
Keyword(s):  
Gas Phase ◽  
Physical Vapor Deposition ◽  
Target Material ◽  
Vacuum System ◽  
Al Alloy ◽  
Alloy Films ◽  
Cu Alloy ◽  
Effect Of Impurities ◽  
Residual Gas ◽  
Vacuum Systems

AbstractThe major sources of impurities in sputtered Al alloy films for interconnects, prepared by physical vapor deposition include those originating from the target material, residual gases present in the vacuum system, and those introduced through the gas delivery system. In this study, we report the effect of impurities incorporated from residual gases present in vacuum systems on the electromigration performance of 0.6 μm wide Al-l%Cu lines. Controlled leaks of isotope gases H2O18, N215, O218, and C13H4, in 10−6 10−9 Torr range, were introduced into a PVD tool during the sputtering process. Using these isotope gases, the impurities originating from residual gases were distinguished from those originating from other sources of impurities. The sputtering target was found to be the major source of H and O impurities in the film, whereas N atoms are introduced in the film mainly through the gas phase. Furthermore, N atoms in the film were found to affect its electromigration behaviour to a larger extent than O and H.

Polarization-Modulated FT-IR Spectroscopy of a Spread Monolayer at the Air/Water Interface

1993 ◽  
Vol 47 (7) ◽  
pp. 869-874 ◽  
Author(s):  
D. Blaudez ◽  
T. Buffeteau ◽  
J. C. Cornut ◽  
B. Desbat ◽  
N. Escafre ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Liquid Water ◽  
Arachidic Acid ◽  
Water Molecules ◽  
Water Interface ◽  
Vibrational Modes ◽  
Experimental Conditions ◽  
Air Water Interface ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

This study devoted to the FT-IR spectroscopy of monolayers spread at the air/water interface is, to our knowledge, the first report presenting complete mid-infrared monolayer spectra perfectly extracted from the strong water vapor bands. This has been possible with the use of the polarization-modulated IRRAS method, which is not sensitive to the isotropic absorptions of the sample environment. On the basis of theoretical modeling and experiments, the best angle of incidence has been found near 76° for detection of intraplane as well as out-of-plane oriented monolayer absorptions. With the use of such experimental conditions, on the normalized difference (covered vs. uncovered water) PM-IRRAS spectra, monolayer vibrational bands come out upward or downward, depending on the orientation of their transition moment with respect to the interface. Application to the study of deuterated arachidic acid and arachidate monolayers allows observation of the vibrational modes of the polar head groups interacting with the liquid water molecules and provides some evidence of their symmetrical anchoring. The vibrational modes of the liquid water subphase contribute to these difference spectra as broad dips that certainly contain information on a possible restructuring of the water molecules at the interface.

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