Growth Temperature Range Research Articles

The first cultivated representatives of the actinobacterial lineage OPB41 isolated from subsurface environments constitute a novel order Anaerosomatales.

The continental subsurface harbors microbial populations highly enriched in uncultured taxa. OPB41 is an uncultured order-level phylogenetic lineage within the actinobacterial class Coriobacteriia. OPB41 bacteria have a wide geographical distribution, but the physiology and metabolic traits of this cosmopolitan group remain elusive. From two contrasting subsurface environments, a terrestrial mud volcano and a deep subsurface aquifer, located in the central part of Eurasia, within the Caucasus petroleum region, we have isolated two pure cultures of anaerobic actinobacteria belonging to OPB41. The cells of both strains are small non-motile rods forming numerous pili-like appendages. Strain M08DHBT is mesophilic, while strain Es71-Z0120T is a true thermophile having a broad temperature range for growth (25-77°C). Strain M08DHBT anaerobically reduces sulfur compounds and utilizes an aromatic compound 3,4-dihydroxybenzoic acid. Strain Es71-Z0120T is an obligate dissimilatory Fe(III) reducer that is unable to utilize aromatic compounds. Both isolates grow lithotrophically and consume molecular hydrogen or formate using either thiosulfate, elemental sulfur, or Fe(III) as an electron acceptor. Genomes of the strains encode the putative reductive glycine pathway for autotrophic CO2 fixation, Ni-Fe hydrogenases, putative thiosulfate/polysulfide reductases, and multiheme c-type cytochromes presumably involved in dissimilatory Fe(III) reduction. We propose to assign the isolated strains to the novel taxa of the species-order levels and describe strain M08DHBT as Anaerosoma tenue gen. nov., sp. nov., and strain Es71-Z0120T as Parvivirga hydrogeniphila gen. nov., sp. nov., being members of Anaerosomatales ord. nov. This work expands the knowledge of the diversity, metabolic functions, and ecological role of the phylum Actinomycetota.

Fabrication of Crystalline Si Thin Films for Photovoltaics

Crystalline Si (c‐Si) thin films have been widely studied for their application to solar cells and flexible electronics. However, their application at large scale is limited by their fabrication process. As reviewed in this paper, many approaches have been studied, but only some of them have been made into large‐scale industrial production. The standard wire sawing of Si ingots cannot be scaled down to produce thin c‐Si wafers and films due to the brittle nature of c‐Si material, the resulting significant thickness variations, and the waste of material. Therefore, techniques based on the kerf‐less processes including “top‐down” and “bottom‐up” approaches have been developed in recent decades. In this review, photovoltaic applications of thin c‐Si wafers with thicknesses ranging from 50 μm down to 1 μm are presented first. Then, methods to fabricate c‐Si thin films based on both approaches are detailed, including slim‐cut, “smart‐cut,” epi‐free, as well as various growth processes such as molecular beam epitaxy, liquid phase epitaxy, ion beam, and chemical vapor deposition processes at a wide range of growth temperatures, from 1000 °C down to 150 °C. The advantages and disadvantages of these methods are presented and compared.

Genome analysis and phenotypic characterization of Halomonas hibernica isolated from a traditional food process with novel quorum quenching and catalase activities

Traditional food processes can utilize bacteria to promote positive organoleptic qualities and increase shelf life. Wiltshire curing has a vital bacterial component that has not been fully investigated from a microbial perspective. During the investigation of a Wiltshire brine, a culturable novel bacterium of the genus Halomonas was identified by 16S rRNA gene (MN822133) sequencing and analysis. The isolate was confirmed as representing a novel species (Halomonas hibernica B1.N12) using a housekeeping (HK) gene phylogenetic tree reconstruction with the selected genes 16S rRNA, 23S rRNA, atpA, gyrB, rpoD and secA. The genome of the new isolate was sequenced and annotated and comparative genome analysis was conducted. Functional analysis revealed that the isolate has a unique phenotypic signature including high salt tolerance, a wide temperature growth range and substrate metabolism. Phenotypic and biochemical profiling demonstrated that H. hibernica B1.N12 possesses strong catalase activity which is an important feature for an industrial food processing bacterium, as it can promote an increased product shelf life and improve organoleptic qualities. Moreover, H. hibernica exhibits biocontrol properties based on its quorum quenching capabilities. Our work on this novel isolate advances knowledge on potential mechanistic interplays operating in complex microbial communities that mediate traditional food processes.

Prevalence and characterization of toxigenic Bacillus cereus group isolated from low-moisture food products.

The present study was conducted to determine the occurrence of B. cereus group members in low-moisture food products by phenotypic and genetic assessment and to evaluate the toxigenic potential of B. cereus group isolates. According to the results of their morphological shape, growth temperature range, strain-specific gene distribution, 79.5% and 20.5% among 112 isolates were identified as B. cereus sensu stricto (s.s.) and B. thuringiensis, respectively and other toxigenic B. cereus group members was not found. All B. cereus group isolates possessed nheABC, hblACD, cytK, entFM genes, and the most frequent gene was nheA. Only three B. cereus s. s. isolates exhibited as emetic toxin gene-harboring B. cereus group. Several B. cereus s.s. and B. thuringiensis isolates from a low-moisture food products were moderate biofilm formers and showed resistance to rifampicin, tetracycline, or clindamycin. The existence of B. cereus s.s. and B. thuringiensis in low-moisture food products indicates the possible risk of foodborne infections due to their virulence potential.

Benefits and detrimental effects of ocean warming for Tasmanian salmon aquaculture

Atlantic salmon (Salmo salar) is the main aquaculture species in Tasmania, Australia. This species is known to be sensitive to ocean temperature and has its own optimal temperature range for exceptional growth. As a hotspot of ocean warming, adaptation planning may be necessary for Tasmanian salmon aquaculture industries in coming years. In this study, we used high-resolution sea surface temperature (SST) satellite observations to investigate ocean temperature variability and trends in the southeastern Tasmania over the past 28 years, and their impacts on growth suitability for sea-farmed Atlantic salmon using a metric called optimal days. We found that long-term ocean warming in the region was evident but showed both positive and negative effects on optimal days. Winter warming would make salmon farms more suitable for salmon growth, while summer warming would make it too warm to grow optimally, which could lead to increased fish disease and even death. This seasonal difference also explained the year-to-year variability in the number of optimal days. Furthermore, spatial distributions of optimal day anomalies indicated that some farm regions were affected more than the others. Northern regions are becoming unsuitable for salmon aquaculture, while southern regions are still optimal for salmon growth in the next few decades. These findings demonstrate the complexity of consequences of global warming for salmon aquaculture industries, and can help stakeholders to develop a blue print for strategizing future farm development and climate change adaptation plans.

Consideration of the Intricacies Inherent in Molecular Beam Epitaxy of the NaCl/GaAs System.

The high cost of substrates for III–V growth can be cost limiting for technologies that require large semiconductor areas. Thus, being able to separate device layers and reuse the original substrate is highly desirable, but existing techniques to lift a film from a substrate have substantial drawbacks. This work discusses some of the complexities with the growth of a water-soluble, alkali halide salt thin film between a III–V substrate and overlayer. Much of the difficulty stems from the growth of GaAs on an actively decomposing NaCl surface at elevated temperatures. Interestingly, the presence of an in situ electron beam incident on the NaCl surface, prior to and during GaAs deposition, affects the crystallinity and morphology of the III–V overlayer. Here, we investigate a wide range of growth temperatures and the timing of the impinging flux of both elemental sources and high energy electrons at different points during the growth. We show that an assortment of morphologies (discrete islands, porous material, and fully dense layers with sharp interfaces) and crystallinity (amorphous, crystalline, and highly textured) occur depending on the specific growth conditions, driven largely by changes in GaAs nucleation which is greatly affected by the presence of the reflection high energy electron diffraction beam.

Increasing the resilience of plant immunity to a warming climate

Extreme weather conditions associated with climate change affect many aspects of plant and animal life, including the response to infectious diseases. Production of salicylic acid (SA), a central plant defence hormone1–3, is particularly vulnerable to suppression by short periods of hot weather above the normal plant growth temperature range via an unknown mechanism4–7. Here we show that suppression of SA production in Arabidopsis thaliana at 28 °C is independent of PHYTOCHROME B8,9 (phyB) and EARLY FLOWERING 310 (ELF3), which regulate thermo-responsive plant growth and development. Instead, we found that formation of GUANYLATE BINDING PROTEIN-LIKE 3 (GBPL3) defence-activated biomolecular condensates11 (GDACs) was reduced at the higher growth temperature. The altered GDAC formation in vivo is linked to impaired recruitment of GBPL3 and SA-associated Mediator subunits to the promoters of CBP60g and SARD1, which encode master immune transcription factors. Unlike many other SA signalling components, including the SA receptor and biosynthetic genes, optimized CBP60g expression was sufficient to broadly restore SA production, basal immunity and effector-triggered immunity at the elevated growth temperature without significant growth trade-offs. CBP60g family transcription factors are widely conserved in plants12. These results have implications for safeguarding the plant immune system as well as understanding the concept of the plant–pathogen–environment disease triangle and the emergence of new disease epidemics in a warming climate.

Retraction Statement: The circadian rhythm regulator RpaA modulates photosynthetic electron transport and alters the preferable temperature range for growth in a cyanobacterium.

Retraction Statement: The circadian rhythm regulator RpaA modulates photosynthetic electron transport and alters the preferable temperature range for growth in a cyanobacterium.

Pseudophaeobacter flagellatus sp. nov., isolated from coastal water.

A Gram-stain-negative, aerobic, motile, rod-shaped novel bacterial strain, designated as MA21411-1T, was isolated from the Korean coast. The colonies were white-yellow-coloured, smooth, convex and entire, spherical and 1.0-1.8 mm in diameter. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain MA21411-1T is closely related to species of the genus Pseudophaeobacter. The 16S rRNA gene sequence similarities between strain MA21411-1T and Pseudophaeobacter arcticus DSM 23566T, Phaeobacter porticola DSM 103148T and Pseudophaeobacter leonis DSM 25627T were 98.31, 97.80 and 97.28 %, respectively. Strain MA21411-1T has a draft genome size of 4 294 042 bp, annotated with 4125 protein-coding genes, and 53 tRNA, three rRNA and one tmRNA genes. The genomic DNA G+C content was 59.2 mol%. Comparative genome analysis revealed that the average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values among strain MA21411-1T and other related species were below the cut-off levels of 95, 70 and 95.5 %, respectively. The growth temperature range for growth was 15-28 °C (optimum, 25 °C), pH range was 6.0-9.0 (optimum, pH 6.0), and salt tolerance range was 0.5-4 % (optimum 0.5 %). Ubiquinone-10 was the sole quinone present in MA21411-1T and all three closely related strains. The major cellular fatty acid (>10 %) of the strain was summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). The polar lipid profile contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and four unidentified polar lipids. Based on the phylogenetic tree, as well as phenotypic, chemotaxonomic and genomic features, strain MA21411-1T represents a novel species of the genus Pseudophaeobacter, for which the name Pseudophaeobacter flagellatus sp. nov. is proposed. The type strain is MA21411-1T (=KCTC 92095T=GDMCC 1.2988T).

Phenotypic Variability and Genetic Diversity of the Pathogenic Fungus Macrophomina phaseolina from Several Hosts and Host Specialization in Strawberry.

Macrophomina phaseolina, is a pathogenic soil-borne fungus that affects more than 500 plant species, causing various types of disease to several crops, among which is the crown and root rot disease in strawberry. Its wide variability has been characterized reiteratively in the literature, but little is known about its virulence mechanisms. Morphological, physiological, genetic and phytopathogenic parameters were evaluated among 32 isolates of Macrophomina from different hosts occurring in Argentina and Spain. Colony characteristics, average size of microsclerotia, chlorate phenotype and mycelial growth at different temperatures (5º-40°C), and pH (3.0-8.0) were recorded. The morphological and physiological traits were heterogeneous and did not show any association with the genetic structure nor with their pathogenicity. Most of the isolates (71.9%) exhibited chlorate-sensitive phenotype. The optimal growth temperature range was between 25°C and 35°C, and the optimal pH varied between 4.0 and 6.0. The genetic structure analyzed with four DNA markers (EF-1α, ITS, CAL and TUB) showed little diversity among isolates of M. phaseolina, with no clear association with the country of origin, but a significant association with the host. Based on their phylogenetic affinity, one isolate was reclassified as M. pseudophaseolina and another one as M. tecta. It is the first report of M. pseudophaseolina causing charcoal rot on beans, in Argentina, and the first report of M. tecta outside Australia. Pathogenicity tests on strawberry plants revealed marked host specialization, being the isolates obtained from strawberry more virulent than those from other hosts.

Simulation of IoT-Based Temperature and Humidity Conditioning System in Screen House

Nowadays, various problems have arisen in agricultural sector. One of which is the decline in productivity of farmers' crops up to 40% which is caused by non-optimal environmental conditions during the plant growth process. This is certainly a challenge for Indonesian farmers to be able to continue in supplying the country's needs for high quality agricultural products. The challenges faced by Indonesian farmers do not only come from the environmental conditions of plant growth, but the development of Industry 4.0 technology also plays an important role in the development of agricultural sector in Indonesia. In order to adapt to these technological changes, a solution is needed in the form of an integrated agricultural equipment with Industry 4.0 technologies such as the Internet of Things (IoT). One of which is creating an IoT-based control and monitoring system that will be applied to the screen house. In this research, an IoT-based temperature and humidity conditioning system was designed in the screen house. The system design is modeled and tested through simulation on Vensim software. Based on the simulation results of system design, the screen house internal temperature can be controlled or maintained in the optimal temperature range for tomato plant growth, which is 18–24oC with an offside value of ±0.5oC. The heating capacity or heating rate required in this system is 10oC/hour. The cooling capacity or cooling rate generated to compensate the influence of external temperature and heating effect on the screen house internal temperature is 1–1.8oC/hour. The heating and cooling rate values generated in this research are still need to be converted into fan and pump PWM values to be implemented in a fan- pad evaporative cooling system.

Numerical Analysis of Nucleation and Growth of Stray Grain Formation during Laser Welding Nickel-Based Single-Crystal Superalloy Part III: Kinetic and Thermodynamic Obviation of Solidification Cracking

To pertinently balance growth kinetics, solidification thermodynamics and dendrite expitaxy of multicomponent nickel-based single-crystal supralloy during laser processing, effect of thermometallurgy determinant factors, including laser power, welding speed and welding configuration, on solidification behavior, such as nonequilibrium solidification temperature range, and dendrite growth, such as dendrite trunk spacing, are progressively advanced to forestall solidification cracking phenomena. Symmetric developments of dendrite trunk spacing and solidification temperature range alongside solid/liquid interface are crystallographically driven by useful (001)/[100] welding configuration to auspiciously bring about crack-insusceptible and well-oriented dendrite growth. Dissimilarly, unsymmetrical developments of dendrite trunk spacing and solidification temperature range alongside solid/liquid interface are crystallographically driven by (001)/[110] welding configuration to insidiously favor crack-unresistant and disoriented dendrite growth. Higher heat input thermodynamically and kinetically boosts wide solidification temperature range, appalling stray grain growth with excess of solute ahead of dendrite tip and large size of crack-unresistant region to thermometallurgically disintegrate epitaxial growth for untoward solidification cracking, and therefore should be strictly withstood. Although geometry of symmetrical weld pool both sides is the same in infelicitous (001)/[110] welding configuration, [100] region of dendrite growth is more liable to ruinous stray grain growth and extensive solidification temperature range than [010] region of dendrite growth to complicate dendrite growth and exacerbate weld integrity. The determinant mechanism of crystallography-aided amelioration of solidification cracking resistance as result of kinetics-and thermodynamics-driven dendrite growth is propitiously proposed. Furthermore, the credible and understandable theoretical predictions are in conformity with the experiment results.

Physiological and molecular response of cotton (Gossypium hirsutum L.) to heat stress at the seedling stage

The ideal temperature range for the optimal growth and development of cotton is 25 °C–32 °C and high temperature adversely affects the metabolic activities of plant cells. This study was aimed to screen heat-tolerant cotton genotypes based on physiological and molecular parameters. Experiments were carried out during 2019–2020 at the MNS-University of Agriculture, Multan, Pakistan. The research comprised two parts. In the first experiment, 30 cotton genotypes were sown in a completely randomized design with three replications under laboratory conditions for the determination of cell membrane thermostability. Principal component analysis was performed, and four genotypes, i.e., two heat-tolerant (‘CRIS-5A’ and ‘VH-338’) and two heat-sensitive (‘FH-242’ and ‘VH-281’) genotypes, were selected. In the second experiment, the screened cotton genotypes were sown in pots in a factorial complete randomized design with three replications and two treatments (normal and heat treatment). Heat stress was applied at the seedling stage, and eight leaf samples (one from each experimental unit) were collected. Two genes were used for molecular analysis and were amplified in all eight cDNA samples. Molecular analysis indicated the presence of HSP70 and HSP26 genes in the cotton genotypes, and the expression of these genes was measured by using ImageJ software. The gene expression level of HSP70 was very high (16.41%) in ‘VH-281’, which is a heat-sensitive genotype under heat stress. The sensitive genotype ‘FH-242’ exhibited the highest gene expression level of HSP26 (20.32%) under normal conditions. A similar sequence of HSP70 gene of Agave sisalana was amplified for the first time in cotton. It is a good indicator for screening heat tolerant cotton genotypes at the molecular level.

How Do Fungi Survive in the Sea and Respond to Climate Change?

With the over 2000 marine fungi and fungal-like organisms documented so far, some have adapted fully to life in the sea, while some have the ability to tolerate environmental conditions in the marine milieu. These organisms have evolved various mechanisms for growth in the marine environment, especially against salinity gradients. This review highlights the response of marine fungi, fungal-like organisms and terrestrial fungi (for comparison) towards salinity variations in terms of their growth, spore germination, sporulation, physiology, and genetic adaptability. Marine, freshwater and terrestrial fungi and fungal-like organisms vary greatly in their response to salinity. Generally, terrestrial and freshwater fungi grow, germinate and sporulate better at lower salinities, while marine fungi do so over a wide range of salinities. Zoosporic fungal-like organisms are more sensitive to salinity than true fungi, especially Ascomycota and Basidiomycota. Labyrinthulomycota and marine Oomycota are more salinity tolerant than saprolegniaceous organisms in terms of growth and reproduction. Wide adaptability to saline conditions in marine or marine-related habitats requires mechanisms for maintaining accumulation of ions in the vacuoles, the exclusion of high levels of sodium chloride, the maintenance of turgor in the mycelium, optimal growth at alkaline pH, a broad temperature growth range from polar to tropical waters, and growth at depths and often under anoxic conditions, and these properties may allow marine fungi to positively respond to the challenges that climate change will bring. Other related topics will also be discussed in this article, such as the effect of salinity on secondary metabolite production by marine fungi, their evolution in the sea, and marine endophytes.

Pseudochrobactrum algeriensis sp. nov., isolated from lymph nodes of Algerian cattle.

Three Gram-negative, rod-shaped, oxidase-positive, non-spore-forming, non-motile strains (C130915_07T, C150915_16 and C150915_17) were isolated from lymph nodes of Algerian cows. On the basis of 16S rRNA gene and whole genome similarities, the isolates were almost identical and clearly grouped in the genus Pseudochrobactrum. This allocation was confirmed by the analysis of fatty acids (C19:cyclo, C18 : 1, C18 : 0, C16 : 1 and C16 : 0) and of polar lipids (major components: phosphatidylethanolamine, ornithine-lipids, phosphatidylglycerol, cardiolipin and phosphatidylcholine, plus moderate amounts of phosphatidylmonomethylethanolamine, phosphatidyldimethylethanolamine and other aminolipids). Genomic, physiological and biochemical data differentiated these isolates from previously described Pseudochrobactrum species in DNA relatedness, carbon assimilation pattern and growth temperature range. Thus, these organisms represent a novel species of the genus Pseudochrobactrum, for which the name Pseudochrobactrum algeriensis sp. nov. is proposed (type strain C130915_07T=CECT30232T=LMG 32378T).

Pelovirga terrestris gen. nov., sp. nov., anaerobic, alkaliphilic, fumarate-, arsenate-, Fe(III)- and sulfur-reducing bacterium isolated from a terrestrial mud volcano

A novel anaerobic, mesophilic, alkaliphilic, chemoorganotrophic bacterium (strain M08fumT) was isolated from a salsa lake of a terrestrial mud volcano (Taman Peninsula, Russia). Cell of strain M08fumT were Gram-stain-negative, rod-shaped, non-spore forming motile rods. The temperature range for growth was 10–45 °C (optimum at 30 °C). The pH range for growth was 7.0–11.0, with an optimum at pH 8.5–9.0. The isolate was capable of organic acids fermentation and anaerobic respiration with elemental sulfur, Fe(III) and arsenate. The end products of fumarate fermentation were succinate, acetate and CO2. The closest phylogenetic relatives of strain M08fumT were members of the family Geopsychrobacteraceae, class Desulfuromonadia. The genome of strain M08fumT had a size of 3.10 Mb with a DNA G + C content of 53.1% (WGS). Genome analysis revealed the presence of genes involved in fumarate fermentation, arsenate reduction and resistance, sulfur respiration and Fe (III) reduction. Based on the phenotypic, genotypic and phylogenetic characteristics we propose to assign strain M08fumT to a new species of a novel genus Pelovirga terrestris gen. nov., sp. nov. within the family Geopsychrobacteraceae. The type strain of Pelovirga terrestris is M08fumT (=KCTC 15919T = VKM B-3407T). This is the first representative of the class Desulfuromonadia, isolated in pure culture from a mud volcano and the first alkaliphile in the family Geopsychrobacteraceae.

Scanning probe analysis of twisted graphene grown on a graphene/silicon carbide template

Overlayer growth of graphene on an epitaxial graphene/silicon carbide (SiC) as a solid template by ethanol chemical vapor deposition is performed over a wide growth temperature range from 900 °C to 1450 °C. Structural analysis using atomic force and scanning tunneling microscopies reveal that graphene islands grown at 1300 °C form hexagonal twisted bilayer graphene as a single crystal. When the growth temperature exceeds 1400 °C, the grown graphene islands show a circular shape. Moreover, moiré patterns with different periods are observed in a single graphene island. This means that the graphene islands grown at high temperature are composed of several graphene domains with different twist angles. From these results, we conclude that graphene overlayer growth on the epitaxial graphene/SiC solid at 1300 °C effectively synthesizes the twisted few-layer graphene with a high crystallinity.

Semi-Transparent Photovoltaic Thermal Greenhouse System Combined With Earth Air Heat Exchanger for Hot Climatic Condition

Abstract Semi-transparent photovoltaic thermal (SPVT) greenhouse system combined with an earth air heat exchanger (EAHE) has been developed to make the system sustainable. The system is designed to cultivate plants in a hot climatic condition, where green net is provided, which bifurcates the enclosed space of the greenhouse into zone-1 and zone-2, and this green net cut the solar radiation incident on the plants. The influence of air changes in zone-1, mass flowrate of air flowing through EAHE, and packing factor on photovoltaic (PV) cell, air of the greenhouse, and the plant temperatures is investigated for a typical harsh summer day by using periodic model of these parameters. Furthermore, for a holistic performance assessment of this SPVT greenhouse, exergy, thermal load leveling, and decrement factor are evaluated. Results indicate that the optimum temperature range for plant growth (30 °C–37 °C) within the greenhouse can be achieved through a combination of ventilation in zone-1 and integration of EAHE. The temperature of plants reduced by 9 °C for 30 air changes in zone-1, and the temperature reduces further by 24 °C when EAHE having a flowrate of 0.5 kg/s is operated. The SPVT greenhouse system also generates 128 kWh of daily overall exergy that makes the system sustainable.

Enhanced thermal transport and corrosion resistance by coating vertically-aligned graphene on zirconium alloy for nuclear reactor applications

Owing to the requirement of higher efficiency, safety reliability and lower maintenance cost for nuclear reactors, the performance improvement of zirconium (Zr) alloy cladding coating materials is becoming increasingly significant. Graphene, with its inherent properties like ultrahigh thermal conductivity, excellent chemical stability, and super-hydrophobicity, has demonstrated enormous potential in the field of corrosion prevention and thermal management, indicating its promising application in cladding materials. Herein, plasma-enhanced chemical vapor deposition (PECVD) was employed for growing vertically-aligned graphene (VG) array on Zr alloy (ZA) substrates. In the deposition process, C2H4 gas was introduced into the reactor as the carbon source and the reactor was kept at a growth temperature range of 650–800 °C, which is 300–400 °C lower than that for traditional graphene synthesis using thermal chemical vapor deposition (CVD). The effects of other growth experimental parameters such as gas flow ratio, radio-frequency power (RF-power), growth temperature, reaction pressure and deposition time were systematically investigated. The corrosion resistance and thermal transport performance of vertical graphene enhanced Zr alloy (VGZA) were studied by using electrochemical corrosion method and heat dissipation test system. The results showed that the samples loaded with vertical graphene could effectively improve the corrosion resistance and heat transport property.

Effect of high temperature homoepitaxial growth of β-Ga2O3 by hot-wall metalorganic vapor phase epitaxy

The effect of high temperature homoepitaxial growth of (010) β-Ga2O3 layer by low pressure hot-wall metalorganic vapor phase epitaxy was investigated. In the growth-temperature range 800–1000 °C, the growth rate decreased with increasing growth temperature and the growth mode changed from three-dimensional island growth to two-dimensional step-flow growth. At 1000 °C, a smooth, twin-free single-crystalline homoepitaxial layer with a structural quality equivalent to that of the substrate could be grown. As the growth temperature increased, the concentration of precursor-derived C impurities decreased, while that of unintentionally incorporated Si impurities increased. It was found that the grown layers were all n-type and showed an effective donor concentration approximately equal to the Si impurity concentration regardless of the C impurity concentration.