Pub Date : 2023-11-15DOI: 10.51316/jst.170.etsd.2023.33.5.7
In the paper, we built a predator-prey model to simulate and study the dynamics of zooplankton and phytoplankton populations under the temperature impact, in which the stage structure is considered in the zooplankton population. Our model is an ordinary differential system of three nonlinear equations with some parameters as temperature-dependent functions and uses the generalized Holling response function. The non-negative and boundedness of the model solutions have been proven. The behaviors of our system are shown by the local stability conditions of the equilibria, especially the co-existence case. The stage transformation of zooplankton was studied through the Hopf bifurcation results of varying the temperature. The analysis and simulation results indicate that the ideal temperature for the co-existence is about 12-21 degrees Celsius. The zooplankton's transformation decreases when the temperature increases, leading to an imbalance in the system. Besides that, we also provided simulation figures to illustrate the found theoretical results.
{"title":"Stability and Hopf Bifurcation Analysis of a Phytoplankton-Zooplankton Model Under Temperature Factor and Stage-Structure Population of Phytoplankton","authors":"","doi":"10.51316/jst.170.etsd.2023.33.5.7","DOIUrl":"https://doi.org/10.51316/jst.170.etsd.2023.33.5.7","url":null,"abstract":"In the paper, we built a predator-prey model to simulate and study the dynamics of zooplankton and phytoplankton populations under the temperature impact, in which the stage structure is considered in the zooplankton population. Our model is an ordinary differential system of three nonlinear equations with some parameters as temperature-dependent functions and uses the generalized Holling response function. The non-negative and boundedness of the model solutions have been proven. The behaviors of our system are shown by the local stability conditions of the equilibria, especially the co-existence case. The stage transformation of zooplankton was studied through the Hopf bifurcation results of varying the temperature. The analysis and simulation results indicate that the ideal temperature for the co-existence is about 12-21 degrees Celsius. The zooplankton's transformation decreases when the temperature increases, leading to an imbalance in the system. Besides that, we also provided simulation figures to illustrate the found theoretical results.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136228652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-15DOI: 10.51316/jst.170.etsd.2023.33.5.1
It is believed that the turbine engine plays a vital role in the performance of aircraft. Most jet engines nowadays use the axial compressor. In axial-flow compressors, the rising pressure through each stage is dependent on the axial flow velocity. A high axial velocity is essential to achieve the design pressure with the minimum number of stages. Thus, before the combustion can proceed, the air velocity must be reduced to about 20% of the compressor outlet velocity. This depletion is accomplished by fitting a diffuser between the compressor outlet and the upstream end of the liner. Throughout much research into diffuser performance, it has been shown that the operation depends particularly on the flow. Besides, there are several problems that could result in the loss of its efficiency. This study will focus on increasing the diffuser performance of a hybrid type one via pressure-recovery coefficient C_p and loss coefficient λ.
{"title":"Effects of Hybrid Diffuser in Axial-Flow Jet Engine Combustor","authors":"","doi":"10.51316/jst.170.etsd.2023.33.5.1","DOIUrl":"https://doi.org/10.51316/jst.170.etsd.2023.33.5.1","url":null,"abstract":"It is believed that the turbine engine plays a vital role in the performance of aircraft. Most jet engines nowadays use the axial compressor. In axial-flow compressors, the rising pressure through each stage is dependent on the axial flow velocity. A high axial velocity is essential to achieve the design pressure with the minimum number of stages. Thus, before the combustion can proceed, the air velocity must be reduced to about 20% of the compressor outlet velocity. This depletion is accomplished by fitting a diffuser between the compressor outlet and the upstream end of the liner. Throughout much research into diffuser performance, it has been shown that the operation depends particularly on the flow. Besides, there are several problems that could result in the loss of its efficiency. This study will focus on increasing the diffuser performance of a hybrid type one via pressure-recovery coefficient C_p and loss coefficient λ.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136228682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-15DOI: 10.51316/jst.170.etsd.2023.33.5.3
The advanced oxidation processes (AOPs) were commonly used in textile dyeing wastewater treatment due to its ability to rapidly degrade dyed compounds. However, its disadvantage is the limited dispersion of ozone in wastewater. To minimize the disadvantage, it is necessary to improve the gas-liquid phase contact to maximize the dispersion of ozone in the wastewater body. Therefore, this study investigated the methylene blue (MB) treatment efficiency in textile dyeing wastewater by performing the ozonation process using a high-performance rotating reactor (HP2R) and compared it with the conventional system. The effect of basic operation parameters such as initial pH, initial methylene blue concentration (Co), rotational speed (ω), and the liquid flow rate (QL) on the decolorization efficiency (η) was evaluated. The results showed that the η of the ozonation using the HP2R reached 98% (pH 8) after only 5 minutes, which was 1.8 times higher than that (54%) of conventional ozonation at the identical period. The decolorization efficiency increased with increasing rotational speed (from 82.0 to 92.5% as ω increased from 30 to 1200 rpm), decreasing liquid flow rate (from 98.0 to 74.9% as QL increased from 0.1 to 0.4 l/min) and decreasing initial concentration of MB (from 98.0 to 88.5% as Co increased from 50 to 200 mg/l). These results show that the combined ozonation in the high-gravity technology can be widely applied to various dyeing wastewater treatment processes in general.
{"title":"Removal of Methylene Blue Intensified Ozonation Using a High-Performance Rotating Reactor","authors":"","doi":"10.51316/jst.170.etsd.2023.33.5.3","DOIUrl":"https://doi.org/10.51316/jst.170.etsd.2023.33.5.3","url":null,"abstract":"The advanced oxidation processes (AOPs) were commonly used in textile dyeing wastewater treatment due to its ability to rapidly degrade dyed compounds. However, its disadvantage is the limited dispersion of ozone in wastewater. To minimize the disadvantage, it is necessary to improve the gas-liquid phase contact to maximize the dispersion of ozone in the wastewater body. Therefore, this study investigated the methylene blue (MB) treatment efficiency in textile dyeing wastewater by performing the ozonation process using a high-performance rotating reactor (HP2R) and compared it with the conventional system. The effect of basic operation parameters such as initial pH, initial methylene blue concentration (Co), rotational speed (ω), and the liquid flow rate (QL) on the decolorization efficiency (η) was evaluated. The results showed that the η of the ozonation using the HP2R reached 98% (pH 8) after only 5 minutes, which was 1.8 times higher than that (54%) of conventional ozonation at the identical period. The decolorization efficiency increased with increasing rotational speed (from 82.0 to 92.5% as ω increased from 30 to 1200 rpm), decreasing liquid flow rate (from 98.0 to 74.9% as QL increased from 0.1 to 0.4 l/min) and decreasing initial concentration of MB (from 98.0 to 88.5% as Co increased from 50 to 200 mg/l). These results show that the combined ozonation in the high-gravity technology can be widely applied to various dyeing wastewater treatment processes in general.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136228655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-15DOI: 10.51316/jst.170.etsd.2023.33.5.8
Brick production is an essential component of the construction industry, contributing significantly to the development of infrastructure and housing worldwide. This study evaluates the energy efficiency and environmental impact of a multi-chamber brick kiln in Vietnam. The study was conducted through a detailed field survey of the kiln, which included measurements of energy consumption and pollutant emissions. The results show that the kiln has a moderate level of energy efficiency, as indicated by the specific energy consumption of 2,035.1 kJ / kg output brick. However, the kiln also produces pollutants, including SOx, CO, and NOx. The study provides recommendations for improving the kiln's energy efficiency based on the results of the energy analysis. Overall, this study highlights the importance of improving the energy efficiency as well as the environmental performance of a Multi Chamber Brick Kiln in Vietnam and provides valuable insights for policy-makers and industry stakeholders.
{"title":"Evaluating the Energy Efficiency and Environmental Impact of a Multi-Chamber Brick Kiln in Vietnam","authors":"","doi":"10.51316/jst.170.etsd.2023.33.5.8","DOIUrl":"https://doi.org/10.51316/jst.170.etsd.2023.33.5.8","url":null,"abstract":"Brick production is an essential component of the construction industry, contributing significantly to the development of infrastructure and housing worldwide. This study evaluates the energy efficiency and environmental impact of a multi-chamber brick kiln in Vietnam. The study was conducted through a detailed field survey of the kiln, which included measurements of energy consumption and pollutant emissions. The results show that the kiln has a moderate level of energy efficiency, as indicated by the specific energy consumption of 2,035.1 kJ / kg output brick. However, the kiln also produces pollutants, including SOx, CO, and NOx. The study provides recommendations for improving the kiln's energy efficiency based on the results of the energy analysis. Overall, this study highlights the importance of improving the energy efficiency as well as the environmental performance of a Multi Chamber Brick Kiln in Vietnam and provides valuable insights for policy-makers and industry stakeholders.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136228650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-15DOI: 10.51316/jst.170.etsd.2023.33.5.2
To reduce the occurrence of cracks in the Inconel 625 nickel-based super-alloy during the Direct Laser Metal Deposition (DLMD) process, this study simulated the temperature and stress fields of thin-walled parts. The model was used to determine the effect of nozzle travel path strategies (single direction and reverse direction) on the final stress distribution, and compared the differences in residual stress distribution within the thin-walled part. The results showed that with the single direction scanning method, the residual stress at both ends of the thin-walled part was relatively high while the stress at the middle was smaller, with a stress difference between the maximum and minimum of about 900 MPa. In contrast, with the reverse direction scanning method, the residual stress in the thin-walled part was distributed relatively evenly, with a stress difference of about 300 MPa between both ends and the center. The experimental results showed that with the single direction scanning method, cracks occurred at both ends and in the middle of the thin-walled part, whereas with the reverse direction scanning method, warping and cracks phenomena were eliminated. The microstructure of the Inconel 625 in the forming layer is characterized by a columnar crystal structure that has a small length and grows perpendicularly to the scanning direction. This growth is continuous between the forming layers. In both cases, the micro-hardness increases with the height of the formed layers; the microhardness values in the left, right, and middle regions are relatively uniform, the microhardness measurement values range from 420 to 450 HV.
{"title":"Effect of Nozzle Travel Path Strategies on the Mechanical Properties of Inconel 625 Superalloy Parts Formed by Direct Laser Metal Deposition","authors":"","doi":"10.51316/jst.170.etsd.2023.33.5.2","DOIUrl":"https://doi.org/10.51316/jst.170.etsd.2023.33.5.2","url":null,"abstract":"To reduce the occurrence of cracks in the Inconel 625 nickel-based super-alloy during the Direct Laser Metal Deposition (DLMD) process, this study simulated the temperature and stress fields of thin-walled parts. The model was used to determine the effect of nozzle travel path strategies (single direction and reverse direction) on the final stress distribution, and compared the differences in residual stress distribution within the thin-walled part. The results showed that with the single direction scanning method, the residual stress at both ends of the thin-walled part was relatively high while the stress at the middle was smaller, with a stress difference between the maximum and minimum of about 900 MPa. In contrast, with the reverse direction scanning method, the residual stress in the thin-walled part was distributed relatively evenly, with a stress difference of about 300 MPa between both ends and the center. The experimental results showed that with the single direction scanning method, cracks occurred at both ends and in the middle of the thin-walled part, whereas with the reverse direction scanning method, warping and cracks phenomena were eliminated. The microstructure of the Inconel 625 in the forming layer is characterized by a columnar crystal structure that has a small length and grows perpendicularly to the scanning direction. This growth is continuous between the forming layers. In both cases, the micro-hardness increases with the height of the formed layers; the microhardness values in the left, right, and middle regions are relatively uniform, the microhardness measurement values range from 420 to 450 HV.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136228653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-15DOI: 10.51316/jst.165.etsd.2023.33.2.7
The study explores the mechanical, optoelectrical and photocatalytic properties of GeS and SnS structures by Density Function Theory (DFT) through Quantum Espresso software. The results show that the GeS and SnS structures are the semiconductor materials at equilibrium with band gaps of 1.75 eV and 1.4 eV, respectively. The band gap of these two structures tends to increase under the tensile strain and decrease under the compressive strain. Especially, at the strain of -10%, the band gap of GeS decreases dramatically and becomes metallic, while the SnS still maintains the semiconductor properties. The absorption coefficient is changed significantly in the ultraviolet region under the biaxial strain. Besides, our calculations also show that the GeS and SnS have photocatalytic properties and can become good candidates for overall water-splitting under the tensile strain. The results obtained from this study are the basis for application in microelectromechanical and optoelectronic devices and cleaning technology.
{"title":"First-Principles Study of Electronic and Optical Properties and Photocatalytic Performance of MS Monolayer under Strain","authors":"","doi":"10.51316/jst.165.etsd.2023.33.2.7","DOIUrl":"https://doi.org/10.51316/jst.165.etsd.2023.33.2.7","url":null,"abstract":"The study explores the mechanical, optoelectrical and photocatalytic properties of GeS and SnS structures by Density Function Theory (DFT) through Quantum Espresso software. The results show that the GeS and SnS structures are the semiconductor materials at equilibrium with band gaps of 1.75 eV and 1.4 eV, respectively. The band gap of these two structures tends to increase under the tensile strain and decrease under the compressive strain. Especially, at the strain of -10%, the band gap of GeS decreases dramatically and becomes metallic, while the SnS still maintains the semiconductor properties. The absorption coefficient is changed significantly in the ultraviolet region under the biaxial strain. Besides, our calculations also show that the GeS and SnS have photocatalytic properties and can become good candidates for overall water-splitting under the tensile strain. The results obtained from this study are the basis for application in microelectromechanical and optoelectronic devices and cleaning technology.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81334456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-15DOI: 10.51316/jst.165.etsd.2023.33.2.3
The research was conducted to select the nitrogen sources and suitable light condition during Ganoderma lucidum submerged culture (isolated in Vietnam). The results showed that organic nitrogen is more suitable than inorganic nitrogen for the growth and synthesis of fungal polysaccharides. The amounts of incellular polysaccharide and exopolysaccharide in this strain was highest when combined 7.5 g/L yeast extract and 2.5 g/L peptone. The light affected on the size, shape and the color of the DL cells in submerged culture. Under optimum condition for nitrogen and light sources, the biomass, IPS and EPS content of DL strain were 13.90 ± 0.27 g DW/L, 15.33 ± 0.97 mg/100mg DW and 2349.76 ± 46.94 mg/L, respectively.
对越南产灵芝深层培养过程中氮源和光照条件的选择进行了研究。结果表明，有机氮比无机氮更适合真菌多糖的生长和合成。当7.5 g/L酵母浸膏和2.5 g/L蛋白胨联合使用时，胞内多糖和胞外多糖的含量最高。光照对深层培养DL细胞的大小、形状和颜色均有影响。在最佳氮源和光照条件下，DL菌株的生物量为13.90±0.27 g DW/L, IPS含量为15.33±0.97 mg/100mg DW, EPS含量为2349.76±46.94 mg/L。
{"title":"Effect of Nitrogen Sources and Illumination Conditions on Ganoderma lucidum Submerged Culture","authors":"","doi":"10.51316/jst.165.etsd.2023.33.2.3","DOIUrl":"https://doi.org/10.51316/jst.165.etsd.2023.33.2.3","url":null,"abstract":"The research was conducted to select the nitrogen sources and suitable light condition during Ganoderma lucidum submerged culture (isolated in Vietnam). The results showed that organic nitrogen is more suitable than inorganic nitrogen for the growth and synthesis of fungal polysaccharides. The amounts of incellular polysaccharide and exopolysaccharide in this strain was highest when combined 7.5 g/L yeast extract and 2.5 g/L peptone. The light affected on the size, shape and the color of the DL cells in submerged culture. Under optimum condition for nitrogen and light sources, the biomass, IPS and EPS content of DL strain were 13.90 ± 0.27 g DW/L, 15.33 ± 0.97 mg/100mg DW and 2349.76 ± 46.94 mg/L, respectively.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91190337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-15DOI: 10.51316/jst.165.etsd.2023.33.2.9
The DDL-8700-7 is a single-needle electronic sewing machine that uses a servo motor to drive the main shaft. This sewing machine has advantages such as being noiseless, energy saving, automatic thread trimming, reverse feed, wiper, and lifting of the needle bar to the highest position when the machine stops... The paper presents the research results of the relationship between the mechanical, electrical, and electronic parts of the SC-920 control circuit in the DDL-8700-7 single-needle sewing machine; analyzing the operating principle of the SC-920 control circuit electronic system according to each control block. In this study, theoretical and experimental research methods were used to measure, test, and evaluate the parameters. The obtained theoretical and experimental research results contribute to building a theoretical scientific basis for making test methods and repairing circuits for some electrical and electronic errors in the error code list of SC-920, helping the repairer identify defects for repair and replacement
{"title":"Researching Electronic System of the SC-920 Control Circuit of the DDL-8700-7 Single Needle Sewing Machine and Application","authors":"","doi":"10.51316/jst.165.etsd.2023.33.2.9","DOIUrl":"https://doi.org/10.51316/jst.165.etsd.2023.33.2.9","url":null,"abstract":"The DDL-8700-7 is a single-needle electronic sewing machine that uses a servo motor to drive the main shaft. This sewing machine has advantages such as being noiseless, energy saving, automatic thread trimming, reverse feed, wiper, and lifting of the needle bar to the highest position when the machine stops... The paper presents the research results of the relationship between the mechanical, electrical, and electronic parts of the SC-920 control circuit in the DDL-8700-7 single-needle sewing machine; analyzing the operating principle of the SC-920 control circuit electronic system according to each control block. In this study, theoretical and experimental research methods were used to measure, test, and evaluate the parameters. The obtained theoretical and experimental research results contribute to building a theoretical scientific basis for making test methods and repairing circuits for some electrical and electronic errors in the error code list of SC-920, helping the repairer identify defects for repair and replacement","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91166216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-15DOI: 10.51316/jst.165.etsd.2023.33.2.5
Boron deposition on both n-Si and n-GaN in the temperature range 250 - 500 °C, has been shown to form diodes with low saturation currents, i.e., electron injection from the n-substrate into the B-layer was efficiently suppressed. Moreover, down to 3-nm-thick B-layers on Si were shown to form a material barrier to Al, opening the possibility of fabricating Au-free gates for gallium-nitride high-electron-mobility transistors (GaN HEMTs). Several different chemical- and physical-vapor deposition (CVD/PVD) methods for depositing B have been studied for fabricating p+n-like Si diodes, called PureB diodes, all with comparable results. In this paper, the deposition of B-layers from diborane in a CVD batch furnace system is evaluated, particularly for use as a barrier material to enable Al-contacting of GaN diodes. These Al-B diodes could provide an option for fabricating low-leakage diodes that are compatible with complementary metal-oxide-semiconductor (CMOS) processing at industrially attractive high throughput. The bulk B has high resistivity, which, combined with the fact that non-uniformities in the nm range, are typical due to gas depletion along the furnace tube and gives uncontrollable, often high diode series resistance. A simulation study shows that Al-B could, nevertheless, be used as a gate stack in HEMTs for low-frequency power applications.
{"title":"Batch Furnace Chemical Vapor Deposition of Pure Boron Layers on Si and GaN Substrates for Low-Leakage-Current Diode Fabrication","authors":"","doi":"10.51316/jst.165.etsd.2023.33.2.5","DOIUrl":"https://doi.org/10.51316/jst.165.etsd.2023.33.2.5","url":null,"abstract":"Boron deposition on both n-Si and n-GaN in the temperature range 250 - 500 °C, has been shown to form diodes with low saturation currents, i.e., electron injection from the n-substrate into the B-layer was efficiently suppressed. Moreover, down to 3-nm-thick B-layers on Si were shown to form a material barrier to Al, opening the possibility of fabricating Au-free gates for gallium-nitride high-electron-mobility transistors (GaN HEMTs). Several different chemical- and physical-vapor deposition (CVD/PVD) methods for depositing B have been studied for fabricating p+n-like Si diodes, called PureB diodes, all with comparable results. In this paper, the deposition of B-layers from diborane in a CVD batch furnace system is evaluated, particularly for use as a barrier material to enable Al-contacting of GaN diodes. These Al-B diodes could provide an option for fabricating low-leakage diodes that are compatible with complementary metal-oxide-semiconductor (CMOS) processing at industrially attractive high throughput. The bulk B has high resistivity, which, combined with the fact that non-uniformities in the nm range, are typical due to gas depletion along the furnace tube and gives uncontrollable, often high diode series resistance. A simulation study shows that Al-B could, nevertheless, be used as a gate stack in HEMTs for low-frequency power applications.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81653816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-15DOI: 10.51316/jst.165.etsd.2023.33.2.6
The paper presents a study on the grain size and tensile strength of annealed ultra-low carbon (ULC) steel containing 0.008 wt.% carbon (C) and various contents of copper (Cu). The annealing temperature was predetermined at 700, 800, and 900 C with the same holding time of 15 minutes and a slow cooling rate. The microstructural result showed that the ferritic grain size of the steel increased with the annealing temperature, e.g. increased to 60 and 65 µm when the temperature raised to 900 C for the 0.112 and 0.285 wt.% Cu steel, respectively. This phenomenon was attributed to the recrystallization of the steel during the annealing process. The coarser grains resulted in a decrease in the tensile strength of the steel despite that the tensile strength of the steel was found to improve with the increased Cu content. The low tensile strengths and good elongation remained in the ULC steel, for instance, the ultimate tensile strength stayed in the range of 234-350 MPa and the elongation remained in the range of 22-35 % dependent on the annealed temperature, and the Cu content. The results show that the content of Cu less than 0.3 wt.% did not have a negative effect on the tensile strength of the studied steel, but caused a deteriorated elongation of the steels annealed at 900 C.
{"title":"Effect of Copper on the Grain Size and Tensile Strength of Ultra-Low Carbon Steel","authors":"","doi":"10.51316/jst.165.etsd.2023.33.2.6","DOIUrl":"https://doi.org/10.51316/jst.165.etsd.2023.33.2.6","url":null,"abstract":"The paper presents a study on the grain size and tensile strength of annealed ultra-low carbon (ULC) steel containing 0.008 wt.% carbon (C) and various contents of copper (Cu). The annealing temperature was predetermined at 700, 800, and 900 C with the same holding time of 15 minutes and a slow cooling rate. The microstructural result showed that the ferritic grain size of the steel increased with the annealing temperature, e.g. increased to 60 and 65 µm when the temperature raised to 900 C for the 0.112 and 0.285 wt.% Cu steel, respectively. This phenomenon was attributed to the recrystallization of the steel during the annealing process. The coarser grains resulted in a decrease in the tensile strength of the steel despite that the tensile strength of the steel was found to improve with the increased Cu content. The low tensile strengths and good elongation remained in the ULC steel, for instance, the ultimate tensile strength stayed in the range of 234-350 MPa and the elongation remained in the range of 22-35 % dependent on the annealed temperature, and the Cu content. The results show that the content of Cu less than 0.3 wt.% did not have a negative effect on the tensile strength of the studied steel, but caused a deteriorated elongation of the steels annealed at 900 C.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90100644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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