scholarly journals Особенности импульсного лазерного отжига пленок ВС-=SUB=-3-=/SUB=- на сапфировой подложке

2019 ◽  
Vol 45 (9) ◽  
pp. 26
Author(s):  
В.Ю. Фоминский ◽  
Р.И. Романов ◽  
A.A. Соловьев ◽  
И.С. Васильевский ◽  
Д.А. Сафонов ◽  
...  
Keyword(s):  
Sheet Resistance ◽  
Morphological Changes ◽  
Pulsed Laser ◽  
Nanosecond Laser Pulse ◽  
Nanosecond Laser ◽  
Initial Structure ◽  
Local Composition ◽  
Before And After ◽  
Original Films ◽  
Increasing Temperature

The morphology, chemical composition, microstructure and electrical properties of BC3 thin films subjected to melting by a nanosecond laser pulse were investigated. The original films were formed by pulsed laser co-deposition of B and C on a sapphire substrate at 150 and 350 °C. Morphological changes in the films depended on their initial structure. However, the structure “frozen” after irradiation in both films was attributed to the B-saturated graphite-like phase, the local composition of which varied due to the formation of inclusions of amorphous boron carbide. Before and after irradiation, the films showed a weakly decreasing dependence of the sheet resistance with increasing temperature from 4.2 to 330 K. After pulsed laser irradiation, the sheet resistance of the films decreased by ~ 2.6 times.

The Change of the Surface Morphology of Organic Films by Laser Pulses

2014 ◽  
Vol 605 ◽  
pp. 557-560
Author(s):  
Anatolij Turiev ◽  
Natalia Tsidaeva ◽  
Aljona Ramonova ◽  
Tengiz Butkhuzi ◽  
Victoria Abaeva ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Surface Topography ◽  
Laser Pulses ◽  
Organic Films ◽  
Threshold Power ◽  
Nanosecond Laser Pulse ◽  
Nanosecond Laser ◽  
Nanosecond Duration ◽  
Atomic Force ◽  
Before And After

In this work by the means of atomic force microscopy (AFM) was investigated the morphology of thin films of organic molecules based on perylene and MPc, irradiated by laser radiation. It is known that the action of nanosecond laser pulse leads to a fragmentation of organic films of perylene, and MnPc derivatives. In this connection, the task was to study the surface topography of the films of perylene and MPc by the means of AFM after irradiation of them by pulsed laser radiation of nanosecond duration. The radiation source used laser with photon energy of 2.34 eV and a pulse width of 10 ns. The films were deposited on the surface of the GaAs (100) using a Knudsen cell in a vacuum 10-5Pa. The study of the surface topography of the irradiated films was carried out under the forvacuum (10-1Pa) using an atomic force microscope. It was discovered that modification of organic films, which manifests itself as a change in the morphology of the surface, takes place. In particular, for the first time found that the effect of laser radiation leads to an irreversible change in the topography of the surface, which is not observed with optical instruments. The comparative analysis of topography measurements of the films parts of the surface before and after laser irradiation shows, that from a certain threshold power density of 2.4 mJ/cm2, the removing of the layer from the surface of the organic film takes place, whereby the film thickness is reduced by approximately 20 nm.

Polydomain Structure of Epitaxial PbTiO3 films on MgO

1997 ◽  
Vol 493 ◽  
Author(s):  
S. P. Alpay ◽  
A. S. Prakash ◽  
S. Aggarwal ◽  
R. Ramesh ◽  
A. L. Roytburd ◽  
...  
Keyword(s):  
Domain Structure ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Theoretical Predictions ◽  
The Stability ◽  
Increasing Temperature ◽  
Stable Domains ◽  
Domain Stability

ABSTRACTA PbTiO3(001) film grown on MgO(001) by pulsed laser deposition is examined as an example to demonstrate the applications of the domain stability map for epitaxial perovskite films which shows regions of stable domains and fractions of domains in a polydomain structure. X-ray diffraction studies indicate that the film has a …c/a/c/a… domain structure in a temperature range of °C to 400°C with the fraction of c-domains decreasing with increasing temperature. These experimental results are in excellent agreement with theoretical predictions based on the stability map.

Effect of a fiber-capillary structure on nanosecond laser pulse propulsion

2017 ◽  
Vol 124 (1) ◽  
Author(s):  
Haichao Yu ◽  
Lugui Cui ◽  
Kai Zhang ◽  
Jun Yang ◽  
Hanyang Li
Keyword(s):  
Laser Pulse ◽  
Nanosecond Laser Pulse ◽  
Nanosecond Laser ◽  
Capillary Structure

scholarly journals Experimental Investigation of Wave Velocity-Permeability Model for Granite Subjected to Different Temperature Processing

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Guanghui Jiang ◽  
Jianping Zuo ◽  
Teng Ma ◽  
Xu Wei
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Wave Velocity ◽  
Pore Fluid ◽  
Rock Matrix ◽  
Permeability Model ◽  
Wave Velocities ◽  
Before And After ◽  
Different Temperatures ◽  
Increasing Temperature

Understanding the change of permeability of rocks before and after heating is of great significance for exploitation of hydrocarbon resources and disposal of nuclear waste. The rock permeability under high temperature cannot be measured with most of the existing methods. In this paper, quality, wave velocity, and permeability of granite specimen from Maluanshan tunnel are measured after high temperature processing. Quality and wave velocity of granite decrease and permeability of granite increases with increasing temperature. Using porosity as the medium, a new wave velocity-permeability model is established with modified wave velocity-porosity formula and Kozeny-Carman formula. Under some given wave velocities and corresponding permeabilities through experiment, the permeabilities at different temperatures and wave velocities can be obtained. By comparing the experimental and the theoretical results, the proposed formulas are verified. In addition, a sensitivity analysis is performed to examine the effect of particle size, wave velocities in rock matrix, and pore fluid on permeability: permeability increases with increasing particle size, wave velocities in rock matrix, and pore fluid; the higher the rock wave velocity, the lower the effect of wave velocities in rock matrix and pore fluid on permeability.

Pulsed laser heating of soot: morphological changes

Carbon ◽  
1999 ◽  
Vol 37 (2) ◽  
pp. 231-239 ◽  
Author(s):  
Randy L Vander Wal ◽  
Mun Y Choi
Keyword(s):  
Laser Heating ◽  
Morphological Changes ◽  
Pulsed Laser ◽  
Pulsed Laser Heating

THERMAL AND MECHANICAL RESPONSES OF GOLD FILMS DURING NANOSECOND LASER-PULSE HEATING

1994 ◽  
Vol 7 (3) ◽  
pp. 175-188 ◽  
Author(s):  
Taiqing Qiu ◽  
Chang-Lin Tien ◽  
Mark A. Shannon ◽  
Richard E. Russo
Keyword(s):  
Laser Pulse ◽  
Pulse Heating ◽  
Nanosecond Laser Pulse ◽  
Nanosecond Laser ◽  
Gold Films ◽  
Mechanical Responses ◽  
Laser Pulse Heating

scholarly journals How effective is river restoration in re-establishing groundwater–surface water interactions? – A case study

2015 ◽  
Vol 19 (6) ◽  
pp. 2663-2672 ◽  
Author(s):  
A.-M. Kurth ◽  
C. Weber ◽  
M. Schirmer
Keyword(s):  
Surface Water ◽  
River Restoration ◽  
Morphological Changes ◽  
Cost Effective ◽  
Urban Stream ◽  
Distributed Temperature Sensing ◽  
River Bed ◽  
Before And After ◽  
Restoration Measures

Abstract. In this study, we investigated whether river restoration was successful in re-establishing groundwater–surface water interactions in a degraded urban stream. Restoration measures included morphological changes to the river bed, such as the installation of gravel islands and spur dykes, as well as the planting of site-specific riparian vegetation. Standard distributed temperature sensing (DTS) and novel active and passive DTS approaches were employed to study groundwater–surface water interactions in two reference streams and an experimental reach of an urban stream before and after its restoration. Radon-222 analyses were utilized to validate the losing stream conditions of the urban stream in the experimental reach. Our results indicated that river restoration at the study site was indeed successful in increasing groundwater–surface water interactions. Increased surface water downwelling occurred locally at the tip of a gravel island created during river restoration. Hence, the installation of in-stream structures increased the vertical connectivity and thus groundwater–surface water interactions. With the methods presented in this publication, it would be possible to routinely investigate the success of river restorations in re-establishing vertical connectivity, thereby gaining insight into the effectiveness of specific restoration measures. This, in turn, would enable the optimization of future river restoration projects, rendering them more cost-effective and successful.

scholarly journals Characteristics of Graphene Oxide Films Reduced by Using an Atmospheric Plasma System

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 802 ◽  
Author(s):  
Chii-Rong Yang ◽  
Shih-Feng Tseng ◽  
Yu-Ting Chen
Keyword(s):  
Graphene Oxide ◽  
Sheet Resistance ◽  
Functional Groups ◽  
Pyrolytic Graphite ◽  
Chemical Oxidation ◽  
Atmospheric Plasma ◽  
Graphene Oxides ◽  
Plasma Irradiation ◽  
Before And After ◽  
Bond Peak

The chemical oxidation method can be used to mass-produce graphene oxides (GOs) from highly oriented pyrolytic graphite. However, numerous oxygen-containing functional groups (hydroxyl, epoxy, carbonyl, etc.) exist in typical GO surfaces, resulting in serious electrical losses. Hence, GO must be processed into reduced graphene oxide (rGO) by the removal of most of the oxygen-containing functional groups. This research concentrates on the reduction efficiency of GO films that are manufactured using atmospheric-pressure and continuous plasma irradiation. Before and after sessions of plasma irradiation with various irradiation times, shelters, and working distances, the surface, physical, and electrical characteristics of homemade GO and rGO films are measured and analyzed. Experimental results showed that the sheet resistance values of rGO films with silicon or quartz shelters were markedly lower than those of GO films because the rGO films were mostly deprived of oxygen-containing functional groups. The lowest sheet resistance value and the largest carbon-to-oxygen ratio of typical rGO films were approximately 90 Ω/sq and 1.522, respectively. The intensity of the C–O bond peak in typical rGO films was significantly lower than that in GO films. Moreover, the intensity of the C–C bond peak in typical rGO films was considerably higher than that in GO films.

Morphological basis for the complex melting behaviour of isotactic polystyrene

e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Mahmoud Al-Hussein ◽  
Gert Strobl
Keyword(s):  
Morphological Changes ◽  
Melting Behaviour ◽  
Temperature Dependent ◽  
Molten Material ◽  
Scanning Calorimetry ◽  
Isotactic Polystyrene ◽  
X Ray ◽  
Long Period ◽  
X Ray Scattering ◽  
Increasing Temperature

AbstractTemperature-dependent small-angle X-ray scattering spectroscopy of isothermally cold crystallized isotactic polystyrene revealed considerable morphological reorganization during subsequent heating to the melt. Both the crystalline thickness and the long period increased continuously with increasing temperature before the samples finally melted. The temperature dependence of these changes correlated very well with the melting behaviour observed with differential scanning calorimetry. As the temperature increased during a heating scan, the initial lamellae that formed during isothermal crystallization showed only little reorganization until they started to melt. Then, the molten material recrystallized continuously into increasingly thicker lamellae at increasing temperature until they finally melted. As the crystallization temperature approached the final melting temperature of the recrystallized lamellae, the initial lamellae melted without further recrystallization and no morphological changes were seen in this case.

Sign in / Sign up

Export Citation Format

Share Document