Effect of gas flow rate on surface morphology and crystal quality of ZnTe epilayers grown on GaAs substrates

2011 ◽  
Vol 46 (4) ◽  
pp. 551-554 ◽  
Author(s):  
Qixin Guo ◽  
Masaki Nada ◽  
Yaliu Ding ◽  
Katsuhiko Saito ◽  
Tooru Tanaka ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Flow Rate ◽  
Gas Flow ◽  
Crystal Quality ◽  
Gas Flow Rate ◽  
Gaas Substrates

Quality of diamond wafers grown by microwave plasma CVD: effects of gas flow rate

1999 ◽  
Vol 8 (2-5) ◽  
pp. 189-193 ◽  
Author(s):  
V Ralchenko ◽  
I Sychov ◽  
I Vlasov ◽  
A Vlasov ◽  
V Konov ◽  
...  
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Microwave Plasma ◽  
Gas Flow Rate ◽  
Plasma Cvd ◽  
Microwave Plasma Cvd

Growth rate, surface morphology, and defect microstructures of β–SiC films chemically vapor deposited on 6H–SiC substrates

1989 ◽  
Vol 4 (1) ◽  
pp. 204-214 ◽  
Author(s):  
H. S. Kong ◽  
J. T. Glass ◽  
R. F. Davis
Keyword(s):  
Growth Rate ◽  
Surface Morphology ◽  
Flow Rate ◽  
Rate Ratio ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Flow Rate Ratio ◽  
Gas Flow Rate ◽  
Carrier Gas ◽  
Carrier Gas Flow

Beta–SiC thin films have been epitaxially grown on 6H–SiC {0001} substrates via chemical vapor deposition (CVD). The growth rate increased linearly with the source/carrier gas flow rate ratio. The activation energy for the growth of β–SiC grown on the Si face of the 6H–SiC substrate was 12 Kcal/mole. These observations are consistent with a surface reaction-controlled process. The as-grown surface morphology is dependent on the terminal layer of the substrate, the growth temperature, and the source/carrier gas flow rate ratio. The C face of a 6H–SiC {0001} substrate caused a higher growth rate and thus poorer surface morphology than the Si face under the same growth conditions. The optimum temperature range for growth of a flat, mirror-like β–SiC surface was determined to be 1773–1823 K in the present CVD system. The microstructure and nucleation of double positioning boundaries were investigated via transmission and scanning electron microscopies. Triangular defects and their modifications were also observed, and their origins have been discussed.

STUDY ON ADHESION STRENGTH OF TIN COATED BIOMEDICAL TI-13ZR-13NB ALLOY

2018 ◽  
Vol 80 (2) ◽  
Author(s):  
A. Shah ◽  
S. Izman ◽  
Siti Nurul Fasehah Ismail ◽  
Mas-Ayu H. ◽  
R. Daud
Keyword(s):  
Adhesion Strength ◽  
Flow Rate ◽  
Gas Flow ◽  
Gas Flow Rate ◽  
Tin Coating ◽  
Testing Method ◽  
Optical Images ◽  
Long Run ◽  
Strength Of Adhesion

One of the crucial factors which determine the success of coated implantation and stability in the long run is the strength of adhesion between the coating and substrate. After implantation, a weakly adhered coating may delaminate and this might seriously restrict the implant’s effectiveness and longevity.  Based on past studies, the quality of TiN coating is directly influenced by the process parameters. The objective of this research is to evaluate the effect of N2 gas flow rate on adhesion strength of biomedical grade Ti-13Zr-13Nb alloy. In this research, N2 gas flow rate of 100, 200 and 300 sccm were varied while the other parameters (substrate temperature and bias voltage) were fixed. The scratch testing method was used to examine the adhesion strength of the TiN coating. This research used the calibrated optical images to verify the total coating failures on the scratched coated samples. The results indicated that the micro droplet form on the TiN coating decreases as the flow rate of the N2 gas increases. In contrast, the TiN coating’s adhesion strength increases with the increase of N2 gas flow rate. It can be concluded that N2 gas flow rate was significant factor in improving the coating properties of TiN on Ti-13Zr-13Nb alloy. 

Effect of Gas Flow Rates on Quality of Aerosol Jet Printed Traces With Nanoparticle Conducting Ink

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Neil Dalal ◽  
Yuan Gu ◽  
Guang Chen ◽  
Daniel R. Hines ◽  
Abhijit Dasgupta ◽  
...  
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Effective Conductivity ◽  
Print Quality ◽  
Gas Flow Rate ◽  
Sem Images ◽  
Flow Rates ◽  
Aerosol Jet Printing ◽  
Cohesive Cracking

Abstract This paper focuses on the influence of carrier gas flow rate (CGFR) and sheath gas flow rate (SGFR) on the quality of conductive traces printed with nanoparticle inks using aerosol jet printing (AJP). This investigation was motivated by previous results of two AJP specimens that were printed at different gas flow rates and yielded significantly different thermal cycling durability lifetimes. A parametric sensitivity study was executed by printing and examining serpentine trace structures at 15 different combinations of CGFRs and SGFRs. The analysis included quantifying the trace's macroscale geometry, electrical properties, and micromorphological features. Interesting macroscale results include an increase in effective conductivity with increasing CGFR. At the microscale, image processing of high magnification scanning electron microscope (SEM) images of the printed traces revealed that agglomerations of silver clusters on the surface of traces became coarser at higher CGFR and also that agglomerates in the bulk were finer than those on the surface. Crystalline silver deposits were observed at all flow rates. In addition, cross sectioning of the printed traces showed higher incidences of buried cohesive cracking at higher gas flow rates. These cohesive cracks reduce the robustness of the traces but may not always be visible from the surface. The degree of cohesive cracking was seen to be broadly correlated with the coarseness of the surface agglomerates, thus suggesting that the coarseness of surface agglomerates may provide a visible surrogate measure of the print quality. The results of this study suggest that print quality may degrade as gas flow rates increase.

SCIENTIFIC AND ENGINEERING PRINCIPLES OF EFFICIENT FUEL USE AND ENVIRONMENTALLY FRIENDLY GAS COMBUSTION IN STOVE PLATES. PART 1. MODERN STATE-OF-THE-ART AND DIRECTIONS FOR IMPROVEMENT THE GAS BURNING IN DOMESTIC GAS COOKERS

2017 ◽  
pp. 3-18 ◽  
Author(s):  
B.S. Soroka ◽  
V.V. Horupa
Keyword(s):  
Natural Gas ◽  
Flow Rate ◽  
Gas Flow ◽  
Renewable Energy Sources ◽  
Combustion Process ◽  
Orifice Diameter ◽  
Firing Process ◽  
Gas Flow Rate ◽  
Gas Combustion ◽  
Gas Stoves

Natural gas NG consumption in industry and energy of Ukraine, in recent years falls down as a result of the crisis in the country’s economy, to a certain extent due to the introduction of renewable energy sources along with alternative technologies, while in the utility sector the consumption of fuel gas flow rate enhancing because of an increase the number of consumers. The natural gas is mostly using by domestic purpose for heating of premises and for cooking. These items of the gas utilization in Ukraine are already exceeding the NG consumption in industry. Cooking is proceeding directly in the living quarters, those usually do not meet the requirements of the Ukrainian norms DBN for the ventilation procedures. NG use in household gas stoves is of great importance from the standpoint of controlling the emissions of harmful components of combustion products along with maintenance the satisfactory energy efficiency characteristics of NG using. The main environment pollutants when burning the natural gas in gas stoves are including the nitrogen oxides NOx (to a greater extent — highly toxic NO2 component), carbon oxide CO, formaldehyde CH2O as well as hydrocarbons (unburned UHC and polyaromatic PAH). An overview of environmental documents to control CO and NOx emissions in comparison with the proper norms by USA, EU, Russian Federation, Australia and China, has been completed. The modern designs of the burners for gas stoves are considered along with defining the main characteristics: heat power, the natural gas flow rate, diameter of gas orifice, diameter and spacing the firing openings and other parameters. The modern physical and chemical principles of gas combustion by means of atmospheric ejection burners of gas cookers have been analyzed from the standpoints of combustion process stabilization and of ensuring the stability of flares. Among the factors of the firing process destabilization within the framework of analysis above mentioned, the following forms of unstable combustion/flame unstabilities have been considered: flashback, blow out or flame lifting, and the appearance of flame yellow tips. Bibl. 37, Fig. 11, Tab. 7.

On the Influence of Fluctuating Flow Rate Upon the Performance and Behaviour of Isothermal Reacting Systems

1998 ◽  
Vol 63 (6) ◽  
pp. 881-898
Author(s):  
Otakar Trnka ◽  
Miloslav Hartman
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Fluidized Bed Reactor ◽  
Computational Techniques ◽  
Continuous Stirred Tank Reactor ◽  
Gas Flow Rate ◽  
Solid Reaction ◽  
Continuous Stirred Tank ◽  
And Performance ◽  
Reacting Systems

Three simple computational techniques are proposed and employed to demonstrate the effect of fluctuating flow rate of feed on the behaviour and performance of an isothermal, continuous stirred tank reactor (CSTR). A fluidized bed reactor (FBR), in which a non-catalytic gas-solid reaction occurs, is also considered. The influence of amplitude and frequency of gas flow rate fluctuations on reactant concentrations at the exit of the CSTR is shown in four different situations.

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