Effect Of Oxygen Partial Pressure Research Articles

Physical and chemical regularities of zinc sulfide concentrate pressure leaching in the presence of lignosulfonate

The study covers physical and chemical regularities of zinc sulfide concentrate oxygen pressure leaching in sulfuric acid. The effect of lignosulfonate concentration (CLSN = 0.2÷0.8 g/dm3), leaching time (τ = 20÷120 min), temperature (T = 393÷423 K), and oxygen partial pressure (РО2= 0.3÷0.7 MPa) on the degree of zinc and iron extraction into the solution and on the cake grain-size distribution was established. It was shown that lignosulfonate additive intensifies zinc and iron extraction into the solution. Maximum extraction of zinc and iron was 89 and 37 %, respectively, for 120 min of leaching at CLSN = 0.6÷0.8 g/dm3. The differential rate law with respect to lignosulfonate was 0.3 for sphalerite, and 0.9 for iron sulfides. A controversial influence of rising temperature on the process under investigation was found. Temperature elevation from 413 to 423 K leads to a decrease in zinc extraction by 3–4 % due to the formation of sulfur-sulfide aggregates over 150 μm in size. The calculated values of apparent activation energy (Еа) of sphalerite and iron sulfide leaching in the presence of lignosulfonate were 30 and 45 kJ/mole, respectively. It was found out that an increase in oxygen partial pressure from 0.3 to 0.5 MPa has a positive influence on leaching and increases extraction of zinc and iron by 22 and 27 %, respectively. However, an increase in oxygen partial pressure up to 0.7 MPa in the presence of lignosulfonate after 40 min of leaching led to a decrease in leaching rate, possibly as a result of lignosulfonate destruction. It was found that differential rate laws with respect to oxygen are 1.2 for sphalerite and 2.5 for iron sulfides.

Effect of Oxygen Partial Pressure on Reactive-Sputtered Ni-YSZ Anode Properties for Low-Temperature Solid Oxide Fuel Cell

Solid oxide fuel cell (SOFC) is a promising next-generation energy conversion device because of its high efficiency, cleanliness, and fuel flexibility. Recently, SOFC operating at low- to intermediate-temperature (LT to IT) range (< 600 ℃) has been studied to overcome the limitations of conventional SOFC, e.g., thermal stability, cost, and limited application. In lowered temperature range, however, charge transfer and transport rates slow down; therefore, SOFCs design with thin film stacks, namely thin film SOFC (TF-SOFC) fabricated on porous anode support have been usually adopted for sufficient power density even at this temperature regime.TF-SOFC usually uses Ni-YSZ (nickel-yttria-stabilized zirconia) cermet for anode functional layer (AFL) to accommodate the deposition of dense electrolyte layers on anode support with relatively large pores because of its reasonable cost, catalytic activity, and electrical conductivity. While various thin film techniques have been reported for AFL fabrication, e.g., pulsed layer deposition (PLD), RF sputtering, etc. Among such techniques, reactive sputtering method, which uses metal target in controlled gas environment (e.g., oxygen environment for oxide deposition), is a versatile method to deposit various types of thin films with fast speed (up to > 1um/hr), which is beneficial in manufacturabilily regarding the usual thickness range of AFL (a few microns). Furthermore, the reactive co-sputtering method can control anode properties such as composition ratio, deposition speed, and morphology in wide ranges.In this study, we fabricate reactive sputtered Ni-YSZ cermet anodes, as prototypes for AFLs of TF-SOFCs, by using a single metal target with various oxygen partial pressure conditions, and characterize their physical and chemical properties. Oxygen partial pressure significantly affects deposition speed, surface morphology, composition, electrochemical performance and its thermal durability at 450 ℃. The Ni-YSZ anode sputtered at the environment of O2/Ar partial pressure ratio of 0.1 sample shows the lowest activation resistance when applied to LT-SOFC’s anode. It is also shown that excessive O2/Ar partial pressure ratio (> 0.2) significantly reduces the deposition speed by approximately one order of magnitude compare to the lower ratio case.

Concentration effect on oxygen quenching behavior of EuxY0.08‐xZr0.92O1.96 and DyxY0.08‐xZr0.92O1.96 phosphors

AbstractThe effect of oxygen partial pressure on the phosphorescence of EuxY0.08‐xZr0.92O1.96 and DyxY0.08‐xZr0.92O1.96 (x = 0.001, 0.005, 0.01, 0.02, 0.05) phosphors was investigated and compared to explore the Ln3+ (Ln3+ = Eu3+, Dy3+) concentration effect on oxygen quenching using a lifetime‐based measurement system equipped with a heatable and pressure controllable chamber. The phosphorescence lifetimes of these two series of phosphors were found to be sensitive to the oxygen partial pressure in high‐temperature environments. Surprisingly, the oxygen sensitivity of DyxY0.08‐xZr0.92O1.96 phosphors markedly increases as the Dy3+ concentration increases, while that of EuxY0.08‐xZr0.92O1.96 phosphors remains nearly constant. Further analysis shows that the oxygen quenching phenomenon is attributable to an oxygen vacancy‐induced non‐radiative decay reduction. However, the mechanisms of non‐radiative decay affected by oxygen vacancies differ, with a charge transfer state (CTS) transition mechanism in EuxY0.08‐xZr0.92O1.96 and a cross‐relaxation mechanism in DyxY0.08‐xZr0.92O1.96 phosphors. The CTS measured from the excitation spectrum is found to be independent of the Eu3+ concentration. In contrast, cross‐relaxation is closely related to the Dy3+ concentration, as demonstrated by the concentration‐quenching behaviours of the phosphorescence intensities and lifetimes, and the non‐exponential decay curves. The present research was expected to shed light on the development and optimization of oxygen/pressure sensors for high‐temperature service.

Effect of Oxygen Partial Pressure on Crystal Structure, Oxygen Vacancy, and Surface Morphology of Epitaxial SrTiO3 Thin Films Grown by Ion Beam Sputter Deposition

Epitaxial SrTiO3 (STO) thin films were grown on (001)-oriented LaAlO3 (LAO) substrates at 800 °C by an ion beam sputter deposition (IBSD). Oxygen partial pressure (PO2) was varied at 1.5 × 10−5, 1.5 × 10−4, and 1.5 × 10−3 Torr during the growth. The effects of PO2 on crystal structure, oxygen vacancy, and surface morphology of the STO films were investigated and are discussed to understand their correlation. It was found that PO2 played a significant role in influencing the crystal structure, oxygen vacancy, and surface morphology of the STO films. All STO films grew on the LAO substrates under a compressive strain along an in-plane direction (a- and b-axes) and a tensile strain along the growth direction (c-axis). The crystalline quality of STO films was slightly improved at higher PO2. Oxygen vacancy was favorably created in the STO lattice grown at low PO2 due to a lack of oxygen during growth and became suppressed at high PO2. The existence of oxygen vacancy could result in a lattice expansion in both out-of-plane and in-plane directions due to the presence of Ti3+ instead of Ti4+ ions. The surface roughness of the STO films gradually decreased and was nearly close to that of the bare LAO substrate at high PO2, indicating a two-dimensional (2D) growth mode. The results presented in this work provide a correlation among crystal structure, oxygen vacancy, and surface morphology of the epitaxial STO films grown by IBSD, which form a useful guideline for further study.

Effect of Sputtering Oxygen Partial Pressure on the Praseodymium-Doped InZnO Thin Film Transistor Using Microwave Photoconductivity Decay Method.

The praseodymium-doped indium-zinc-oxide (PrIZO) thin film transistor (TFT) shows broad application prospects in the new generation of display technologies due to its high performance and high stability. However, traditional device performance evaluation methods need to be carried out after the end of the entire preparation process, which leads to the high-performance device preparation process that takes a lot of time and costs. Therefore, there is a lack of effective methods to optimize the device preparation process. In this paper, the effect of sputtering oxygen partial pressure on the properties of PrIZO thin film was studied, and the quality of PrIZO thin film was quickly evaluated by the microwave photoconductivity decay (µ-PCD) method. The μ-PCD results show that as the oxygen partial pressure increases, the peak first increases and then decreases, while the D value shows the opposite trend. The quality of PrIZO thin film prepared under 10% oxygen partial pressure is optimal due to its low localized defect states. The electric performance of PrIZO TFTs prepared under different oxygen partial pressures is consistent with the μ-PCD results. The optimal PrIZO TFT prepared under 10% oxygen partial pressure exhibits good electric performance with a threshold voltage (Vth) of 1.9 V, a mobility (µsat) of 24.4 cm2·V−1·s−1, an Ion/Ioff ratio of 2.03 × 107, and a subthreshold swing (SS) of 0.14 V·dec−1.

Effects of temperature on the locomotor performance and contraction properties of skeletal muscle from two Phrynocephalus lizards at high and low altitude.

Locomotor performance and skeletal muscle contraction are critical for animals andare susceptible tochanges in the externalthermal environment, especially for ectotherms. Phrynocephalus erythrurus,which isendemic tothe Qinghai-Tibetan plateau, is known for living at the highest elevation among all reptiles in the world (4500-5300m). In this study, which comparesP. erythrurus withthe lowland Phrynocephalus przewalskii, we evaluated the locomotor performance at different body temperatures, the effects of temperature and oxygen partial pressure (PO2) on the contractile properties of iliofibularis (IF) muscle in vitro, ATPase activity of IF muscle at different temperatures, and the fiber types of IF muscle. Lowland P. przewalskii runs significantly faster than highland P. erythrurus at all test body temperatures. Almost all contractile properties of the IF muscle of P. przewalskii were better than that of P. erythrurus under all test temperatures and PO2. However, P. erythrurus could achieve both optimal isometric (e.g., dPo/dt) and optimal isotonic (e.g., Vmax) contraction at a lower temperature compared with P. przewalskii. Multi-factor analysis further revealed that temperature has a significant effect on the contractile properties of IF muscle for both species. Although the proportion of fibers types and ATPase activities of IF muscle have no significant interspecies difference, the changing pattern of ATPase activities with temperature is consistent with certain contractile properties and locomotor performance. The interspecies differences in locomotor ability and contractile properties of skeletal muscle in high- and low-altitude lizards may be the results of long-term adaptation tothe local environment.

The effects of soybean storage under controlled atmosphere at different temperatures on lipid oxidation and volatile compounds profile

This study aimed to evaluate the effects of low oxygen partial pressure (pO2) and high carbon dioxide partial pressure (pCO2) combined with different temperatures on the oil acidity and peroxide values of two soybean cultivars (NA 5909 RG and FEPAGRO 37 RR). The volatile compounds correlated to lipid oxidation were also evaluated. Soybeans were stored for seven months under ambient and controlled atmosphere (CA) conditions at three temperatures (20, 25, and 30 °C). Storage under ambient conditions increased acidity and peroxide value regardless of the temperature. CA storage with low pO2 reduced oil acidity and its combination with high pCO2 had no positive effects on oil acidity and peroxide values. Grains of FEPAGRO 37 RR stored under ambient air showed higher 1-octne-3-ol amount compared to CA. The higher storage temperature increased (E)-2-heptenal and decanal amount in grains of cultivar NA 5909 RG. In addition, the ambiente air storage provide higher γ-Butyrolactone in relation to CA storage. Moreover, in both cultivars the CA storage technique provides lower (E)-2-hexenal content. This compound, together with hexanal are potential lipid deterioration markers of soybeans. CA storage is a promising tool for soybean grains preservation and the effect is mainly due to the oxygen reduction, with no additional effect of CO2 increasing.

Effect of oxygen partial pressure on microstructure, optical and electrical property of C-Al co-doped ZnO films

C-Al co-doped ZnO films with superior optical and electrical property have been deposited at oxygen partial pressure range 1–7 Pa by pulse laser deposition. The influences of oxygen pressure on crystalline, optical and electrical property have been investigated. The C-Al co-doped ZnO films exhibit a superior crystallinity and greater grain size in the range of 1 Pa–3 Pa compared to AZO films. Furthermore, carbon doping at various oxygen partial pressure significantly improves the optical and electrical property. C-Al co-doped ZnO film reaches the lowest resistivity of 3.1×10-4 Ω cm at 1 Pa. The average transmittance is higher than 85% and attains the optimal value of 89.9 %.

Effect of oxygen partial pressure on the stability of Ce0.8Zr0.2O2-δ solid solution using genetic algorithm and lattice statics

Atomic distribution is a key parameter that determines the stability of solid solution materials. We studied the effect of oxygen partial pressure on atomic distribution in cubic Ce0.8Zr0.2O2-δ solid solutions. The oxygen partial pressure was varied by changing the number of the oxygen vacancies, and the cubic solid solutions were constructed from the 2×2×2 fluorite CeO2 supercell. We employed genetic algorithm and lattice statics to effectively find the energetically-favorable structures among a huge number of configurations.

Effect of processing parameters on the defects state in Ni0.65Zn0.35Al0.8Fe1.2O4 thin films

Ferromagnetic resonance (FMR) technique is used to investigate the effect of oxygen partial pressure (PO2) and substrate temperature (TS) on the defect properties of Ni0.65Zn0.35Al0.8Fe1.2O4 (NZAFO) thin films. NZAFO thin films are deposited on MgAl2O4 (MAO) (100) substrates using pulsed laser deposition technique under various PO2 and TS. The FMR study reveals that the FMR parameters such as linewidth, line intensity and g-factor of the NZAFO thin films are sensitive to the variations in PO2 and TS. The observed changes in the FMR parameters are attributed to the variation of density and uniformity of defects in NZAFO thin films. Thus the significance of the present work suggests that the FMR may serve as an effective tool to monitor the growth condition of complex oxide films.

Effects of Oxygen Partial Pressure on the Properties of SnOx Thin Films Doped with Indium

This study examined the effects of the oxygen partial pressure on the properties of heavily indium-doped tin-oxide (In-SnOx) thin films grown at room temperature by reactive direct-current pulse sputtering from a mixed metallic target containing Sn (70 atomic %)-In (30 atomic %). X-ray photoelectron spectroscopy (XPS), dynamic secondary-ion mass spectrometry, X-ray diffraction (XRD), and Hall Effect measurements showed that the In-SnOx samples prepared with oxygen pressures of 10–20% had metallic properties. This was attributed to the notable Sn0 area ranges of 5.6–17.3%, low resistivity ranges of 5.5×10−3–2×10−4 Ωcm, and the high carrier concentration ranges of 3.5×1021–5.1×1022/cm3. On the other hand, the Sn4+ area and the resistivity increased significantly to 73.3% and 9.4 Ωcm. In comparison, the Sn2+ area and the electron concentration decreased dramatically to 23.6% and 6.5×1016/cm3, respectively, with increasing oxygen partial pressure up to 30%. The samples prepared with oxygen pressures higher than 20% exhibited nonmetallic properties with the dominant n-type SnO2 phase. This steep increase in the Sn4+ area was attributed to an increase in the oxygen contents in the samples, resulting in a decrease in the number of oxygen vacancy donors in the samples prepared with oxygen pressures higher than 20%. The decrease in the Sn2+ area was related to a decrease in the indium (In) contents in the samples, which also decreased the number of metal acceptors in the samples. XRD also showed that the metallic indium stannide (In0.2Sn0.8) and In–Sn–O(ITO) peaks coexisted for samples prepared with an oxygen pressure of 0–10%. In contrast, the samples prepared with oxygen pressures higher than 20% had an amorphous structure with SnO2 and SnO phases, supporting the XPS and Hall Effect measurement results.

TEM Study of Oxygen Partial Pressure Effect on Early LSM-YSZ Surface Interactions in Solid Oxide Fuel Cells

Abstract Long-term stability studies indicate that cathode degradation is one of the main failure mechanisms in anode-supported SOFCs. In order to better understand the microstructural degradation mechanisms of the cathode and the influence of oxygen partial pressure at relevant operating temperatures, the authors of this article acquired TEM samples from technological cells to study cation interdiffusion mechanisms and LSM-YSZ interactions, particularly in areas where LSM grains are in contact with YSZ electrolyte. Here they present and interpret the results.

Equilibrium Distributions of Pb, Bi, and Ag between Fayalite Slag and Copper-Rich Metal, Calcium Ferrite Slag and Copper-Rich Metal. Thermodynamic Assessment and Experimental Study at 1250 °C

Rising concentrations of impurities are expected at copper fire-refining stage due to lower availability of high-quality copper concentrates and due to increasing recycling of electronics and other secondary materials in primary copper smelting. Extra steps involving the removal of impurities from copper into the slag phase may provide a solution, but better understanding of thermochemistry is needed to evaluate the feasibility of changes in the process. In the present study, the distribution coefficients of Pb, Bi, and Ag between the fayalite or calcium ferrite slags and copper-based metal at 1250 °C were measured experimentally, using high-temperature equilibration, rapid quenching, and electron probe X-ray microanalysis (EPMA). The experiments were undertaken in a closed system using a modified substrate support technique, at relatively high oxidizing conditions typical for copper refining. The improved substrate technique enables the measurement of distributions coefficients for slags in equilibrium with solid spinel (Fe3O4) or dicalcium ferrite (Ca2Fe2O5). Experimental results of the present study and the literature data were analyzed together using thermodynamic modeling. As a result, thermodynamic database has been developed and used to predict the effects of oxygen partial pressure, wt% Cu in slag, temperature, and Fe/SiO2 and Fe/CaO in slags on the distribution coefficients of Pb, Bi, and Ag for the fayalite and calcium ferrite slag systems.

Effects of Oxygen Partial Pressure on Wood-Based Activated Carbon Treated with Vacuum Ultraviolet Light

This study uses vacuum ultraviolet (VUV) light with a wavelength of 172 nm as a surface treatment to enhance the adsorption capacity of wood-based activated carbon (AC). The AC surface treatment is performed under three O2 partial pressure conditions—5.0 × 104 Pa, where ozone (O3) effects dominate; 6.3 × 10−6 Pa, where VUV effects dominate; and 1.9 × 103 Pa for a balanced condition. For the O3-dominant condition, only graphene edge defects are etched (no aromatic carbon bonds are etched), resulting in increased surface roughness. When the VUV effects dominate, aromatic carbon bonds are cleaved, which then reacted with O2 or water adsorbed inside the pores. This increased both the number and size of the mesopores. Under the balanced conditions, the water adsorption capacity was enhanced by 45.5%, which is higher than that obtained before VUV exposure or with VUV under other conditions. This is because the surface roughness increased, as well as the pore sizes and numbers under the balanced condition. These results indicate that we can control VUV-based AC surface treatments via O2 partial pressure.

The influence of oxygen partial pressure on the crack propagation of superalloy under fatigue-creep-environment interaction

We elucidate here the effect of low oxygen partial pressure on the dwell fatigue crack growth rate (DFCGR) of 718Plus alloy at high temperature. In comparison under the air and vacuum conditions with lower oxygen partial pressure, the DFCGR of 718Plus alloy reduced by three orders of magnitude at 704 °C at lower oxygen partial pressure than that of in air condition. By analysis of microstructure, oxide, and crack path under different conditions, it was considered that the oxygen-induced dynamic embrittlement (DE) was the dominant impact mechanism for fatigue crack propagation at high-temperature in 718Plus alloy. Meanwhile, the stress-accelerated grain boundary oxidation (SAGBO) mechanism also played a significant role, especially in the long step-wise period. In addition, the types of oxide formed in creep process were directly related to the oxygen partial pressure and oxidation time.

Application of continuous monitoring of intracranial pressure and brain oxygen partial pressure in the treatment of patients with severe craniocerebral injury

To investigate the effects of continuous monitoring intracranial pressure (ICP) and brain oxygen partial pressure (PbtO2) on the prognosis of patients with severe craniocerebral injury. A prospective randomized controlled trial was conducted. Seventy patients with severe craniocerebral injury with a Glasgow coma score (GCS) 4-8 admitted to the neurosurgical intensive care unit (NICU) of the People's Hospital of Inner Mongolia Autonomous Region from January 2017 to May 2020 were enrolled, and they were divided into ICP monitoring group and ICP+PbtO2 monitoring group by random number table. Patients in ICP monitoring group received ICP monitoring and were given traditional treatment of controlling ICP and cerebral perfusion pressure (CPP), the therapeutic target was ICP < 20 mmHg (1 mmHg = 0.133 kPa) and CPP > 60 mmHg. Patients in ICP+PbtO2 monitoring group were given ICP and PbtO2 monitoring at the same time, and oxygen flow was adjusted on the basis of controlling ICP and CPP to maintain the PbtO2 > 20 mmHg, and the therapeutic target of ICP and CPP was the same as the ICP monitoring group. ICP and PbtO2 values were recorded during monitoring in the two groups, the results of CPP, GCS and arterial blood gas analysis were recorded, and the prognosis at 3 months and 6 months after injury was compared by Glasgow outcome scale (GOS) score between the two groups. GOS score > 3 was considered as good prognosis. Kaplan-Meier survival curve was drawn, and the 3-month and 6-month cumulative survival rates of the two groups were analyzed. Linear regression analysis was used to further evaluate the relationship between PbtO2 and GOS score. Finally, a total of 70 patients with severe craniocerebral injury were enrolled in the analysis, 34 patients received ICP combined with PbtO2 monitoring and guided therapy, and 36 patients received ICP monitoring alone. The average ICP of ICP+PbtO2 monitoring group was significantly lower than that of ICP monitoring group (mmHg: 13.4±3.2 vs. 18.2±8.3, P < 0.01). Although the CPP in both groups was great than 60 mmHg, the average CPP of ICP+PbtO2 monitoring group was significantly higher than that of ICP monitoring group (mmHg: 82.1±10.5 vs. 74.5±11.6, P < 0.01). No significant difference was found in average GCS score or arterial partial pressure of carbon dioxide (PaCO2) between the ICP+PbtO2 monitoring group and ICP monitoring group [GCS score: 5.3±2.3 vs. 5.2±2.2, PaCO2 (mmHg): 33.5±4.8 vs. 32.6±5.2, both P > 0.05]. The average arterial partial pressure of oxygen (PaO2) of ICP+PbtO2 monitoring group was obviously higher than that of ICP monitoring group (mmHg: 228.4±93.6 vs. 167.3±81.2, P < 0.01). Compared with the ICP monitoring group, the good outcome rates of 3 months and 6 months after injury in the ICP+PbtO2 monitoring group were significantly higher (3 months: 67.6% vs. 38.9%, 6 months: 70.6% vs. 41.7%, both P < 0.05). Kaplan-Meier survival curve showed that the 3-month and 6-month cumulative survival rates of ICP+PbtO2 monitoring group were significantly higher than those of ICP monitoring group (3 months: 85.3% vs. 61.1%, Log-Rank test: χ2 = 5.171, P = 0.023; 6 months: 79.4% vs. 55.6%, Log-Rank test: χ2 = 4.511, P = 0.034). Linear regression analysis showed that PbtO2 was significantly correlated with GOS score at 3 months and 6 months after injury in patients with severe craniocerebral injury (r values were 0.951 and 0.933, both P < 0.01). PbtO2 compared with ICP monitoring guiding therapy is valuable in improving the prognosis of patients with severe craniocerebral injury. It can improve the prognosis at 3-6 months after injury.

Effects of sequential annealing in low oxygen partial-pressure and NO on 4H-SiC MOS devices

The effects of low oxygen partial pressure (low-pO2) annealing and NO annealing on both performance and reliability of silicon carbide (SiC) MOS capacitors are verified, and the sequential annealing in low-pO2 and NO is also investigated. The sequential annealing is effective to improve the reliability of SiC MOS capacitors but shows slight deterioration of interface property. The results show that annealing in the atmosphere of low partial pressure oxygen changes the distribution of defect about the SiO2/SiC interface, and influences the following NO annealing effect. The mechanism of oxidation and annealing is discussed, and some suggestions on annealing are given. This experiment provides some inspiration for the combination of annealing processes and the optimization of annealing conditions.

Effect of oxygen partial pressure on the behavior of Ga-doped ZnO/p-Si heterojunction diodes fabricated by reactive sputtering

A systematic investigation of Ga-doped ZnO (GZO) films deposited by radio frequency reactive magnetron co-sputtering of Zn and GaAs has been carried out toward the realization of n-GZO/p-Si heterojunction diodes. X-ray diffraction and X-ray photoelectron spectroscopy studies of these films have shown a strong dependence of the c-axis orientation of crystallites, Ga/Zn ratio, oxygen vacancies and chemisorbed oxygen species on the partial pressure (percentage) of oxygen in the Ar-O2 sputtering atmosphere. The GZO films deposited at low O2 percentage (≤ 6%) exhibit Ga/Zn ratio ~ 0.03 and consequently high conductivity ~ 103 Ω−1 cm−1 with carrier concentration > 1020 cm−3, leading to the formation of non-rectifying contact with p-Si. A significant finding of the present study is that the doping level and conductivity of GZO layer can be controlled by O2 percentage in sputtering atmosphere, which has been utilized to fabricate heterojunction diodes with GZO films deposited above 6% O2, which possess low Ga/Zn ratio ~ 0.01 and carrier concentration ≤1019 cm−3. In particular, the diode fabricated with 8% O2 displays ideality factor ~ 7 and reverse saturation current ~ 2 × 10–6 A, along with improved turn-on-voltage and series resistance. The nearly complete c-axis orientation, absence of oxygen vacancies and presence of chemisorbed oxygen at the grain boundaries in GZO layer appear to facilitate improved diode performance.

Influence of oxygen partial pressure on SmBa2Cu3O7-δ film deposited by laser chemical vapor deposition

ABSTRACT Laser chemical vapor deposition (LCVD) was applied to prepare SmBa2Cu3O7-δ (SmBCO) superconductive films on single-crystalline LaAlO3 (100) substrates. The effect of oxygen partial pressure (P O2) on the crystal orientation, microstructure, and superconducting property of SmBCO film were investigated thoroughly. The results of X-ray diffraction (XRD) and Raman showed that the crystal orientation of SmBCO film was pure c -axis orientation at the P O2 of 200 Pa, and the a- axis orientation grains gradually emerged in SmBCO film with the increase of P O2. The deposition rate, critical temperature (T c), critical current density (J c) firstly increased and then decreased with the increase of P O2. At the P O2 of 200 Pa, the SmBCO film had smooth and dense surface, the lowest FWHM of φ-scan (1.1°), the highest T c (89.2 K) and J c (2.04 MA/cm2), which indicated that SmBCO superconductive films possessed excellent crystal structure and superconducting performance.

Impact of controlled atmosphere storage on physiological quality of soybean seed

Soybean seed tends to lose its quality property if kept in inappropriate storage conditions. The aim of this work was to evaluate the effect of different oxygen (O2) and carbon dioxide (CO2) partial pressures, combined with different temperatures on the soybean seed physiological potential maintenance. In 2017, seed of the cultivars 8473 RSF and TECIRGA 6070RR were stored for 7 months under: [1] ambient air; controlled atmosphere (CA) with [2] 1 kPa O2 + 0.04 kPa CO2; [3] 2 kPa O2 + 0.04 kPa CO2; [4] 2 kPa O2 + 30 kPa CO2; and [5] 2 kPa O2 + 80 kPa CO2. In 2018, seed of NA 5909 RG and FEPAGRO 37RR were stored for 7 months under the following conditions: [1] ambient air; and CA with [2] 1 kPa O2 + 0.04 kPa CO2; [3] 1 kPa O2 + 15 kPa CO2; [4] 1 kPa O2 + 30 kPa CO2; [5] 2 kPa O2 + 0.04 kPa CO2. In both years the storage conditions were conducted at three temperatures (20, 25 and 30 °C). The seed were stored with moisture content between 11 and 11.5. The reduction of the O2 until 1.0 kPa maintained higher germination, however, storage above 25 °C is not recommended. High CO2 partial pressure did not have additional effects on physiological quality conservation compared to solely low O2. Seed of 8473 RSF stored at 25 and 30 °C resulted in low germination, regardless of the CA condition. NA 5909 RG reached 80% of germination, when CA was used, regardless of temperature. The ambient air did not maintain the seed physiological quality when stored at 25 and 30 °C and CA may efficiently maintain the physiological quality of soybean seed after 7 months, even in the higher temperature for NA5909 RG, but not for the other cultivars.