Phosphorus Ions Research Articles

The effect of conventional and self-ligating brackets on salivary biochemical indicators

The use of orthodontic fixed systems is often accompanied by physical discomfort, pain of varying intensity, psycho-emotional stress, and sleep disturbances. Treatment also affects salivary cortisol, alpha-amylase, magnesium, calcium, and inorganic phosphorus concentrations, although data are conflicting and scarce. The aim of our study was to compare of electrolytes and alkaline phosphatase concentrations in oral fluid after 2 months of treatment (conventional and self-ligating braces respectively). In total40 patients (20 in each group) were studied. According to the obtained results, the concentrations of calcium and alkaline phosphatase differ significantly between standard and self-ligating treatments, while magnesium and phosphorus ions do not change. Based on the results of the study, calcium and alkaline phosphatase indicators can be used to prevent expected side effects of treatment.

The death of Korean fir (Abies koreana) affects soil symbiotic fungal microbiome: Preliminary findings

The population of the Korean fir, Abies koreana, is declining at an accelerating rate, and the average mortality rate in 2019 exceeded 36.43% on Mt. Hallasan in Jeju Island, Republic of Korea. Several prior studies have reported different reasons with various interpretations, indicating that additional data, such as data on microbial communities that promote plant growth and resistance to abiotic stresses, are required to understand the phenomenon further. This is the first investigation that documents the changes in the soil microbial and fungal community and soil physicochemical properties resulting from the death of the Korean fir. In our case, high throughput sequencing data have been provided for the soil microbiome and mycobiome of Korean fir trees, identifying the microbial composition differences before and after the decline in the health of Korean fir trees. The results showed that the soil fungal community was considerably shaped in response to the decline in the health of Korean fir rather than the soil bacterial community. The decline in health or the death of Korean fir trees contributed to the decrease in diversity and dominance of symbiotic fungi such as Russula, Sebacina, and Phenoliferia in the forest ecosystem. It also weakened the complexity and ecological competition of the fungal co-occurrence network. Structural equation modeling showed that the death of Korean fir was strongly associated with the concentrations of soil nutrients such as available phosphorus (P2O5) and potassium ion (K+) concentrations and low moisture content, adversely affecting the symbiotic relationship with ectomycorrhizal fungi. Our findings shed light on the critical taxa of mycobiome of live and dead A. koreana plants and their relationship with ecological edaphic factors, highlighting their potential role as biomarkers for the death of Korean fir.

Reducing the qualification time of low energy phosphorus ion implantation process using spectroscopic ellipsometry for dynamic random access memory production line

In this study, a new method has been applied to monitor the low energy phosphorus ion implantation process in dynamic random access memory production line using spectroscopic ellipsometry (SE). The dose sensing ability of SE is similar level to that of wavelength dispersive x-ray fluorescence (XRF) and the energy sensing ability is almost twice stronger than that of XRF. The coefficients of determination of SE have been confirmed that they are higher than 95% both for the implantation dose and implantation energy as variables. In the case of XRF measurement, the photoresist (PR) should be removed by ashing and strip processes before measuring the phosphorus concentration to avoid chamber contamination in high vacuum. However, there is free of contamination issue for SE in the presence of PR, so the phosphorus concentration can be monitored by SE immediately after the ion implantation. Consequently, the qualification time can be reduced at least as much as waiting and running time of the ashing and the strip processes. It is worth to note that the measuring speed of SE is 33 times faster than that of XRF. Considering the advantage of fast SE measurement speed, the number of measurement points was increased from 5 to 21 including 8 points of wafer edge to enhance monitoring of product quality. In this work, the qualification time has been reduced effectively by 39.2% in average in production lines by using SE technology.

Population Response of Rhizosphere Microbiota of Garden Pea Genotypes to Inoculation with Arbuscular Mycorrhizal Fungi.

This study of a legume's rhizosphere in tripartite symbiosis focused on the relationships between the symbionts and less on the overall rhizosphere microbiome. We used an experimental model with different garden pea genotypes inoculated with AM fungi (Rhizophagus irregularis and with a mix of AM species) to study their influence on the population levels of main trophic groups of soil microorganisms as well as their structure and functional relationships in the rhizosphere microbial community. The experiments were carried out at two phenological cycles of the plants. Analyzes were performed according to classical methods: microbial population density defined as CUF/g a.d.s. and root colonization rate with AMF (%). We found a proven dominant effect of AMF on the densities of micromycetes and actinomycetes in the direction of reduction, suggesting antagonism, and on ammonifying, phosphate-solubilizing and free-living diazotrophic Azotobacter bacteria in the direction of stimulation, an indicator of mutualistic relationships. We determined that the genotype was decisive for the formation of populations of bacteria immobilizing mineral NH4+-N and bacteria Rhizobium. We reported significant two-way relationships between trophic groups related associated with soil nitrogen and phosphorus ions availability. The preserved proportions between trophic groups in the microbial communities were indicative of structural and functional stability.

Separation of Phosphorus from Phosphorus-concentrated Steelmaking Slag

Since 10 million tons of steelmaking slag, which contains a few percent of phosphorus, are annually produced, the phosphorus amount in the slag is equivalent to the annual import volume of phosphorus rock in Japan. Therefore, the steelmaking slag is attracting attention as a potential phosphorus resources. Phosphorus-concentrated slag obtained by the dephosphorization reaction between high phosphorus hot metal and oxidizing slag at high temperature contains phosphorous comparable to that of phosphorus rock. However, because of high FeO concentration, it is difficult to use for phosphorus resources directly. In this work, the effects of pH, acid type and leaching method on the dissolution behavior of phosphorus from P-concentrated slag were investigated. As a result, phosphorus dissolution progressed at lower pH, and was promoted by the addition of citric acid, which is known as a chelate former. When nylon mill pot stirring with citric acid and alumina mill pot stirring with nitric acid were compared to impeller stirring, respectively. By combining nylon mill pot stirring and citrate leachate, phosphorus dissolution was accelerated, because the slag was pulverized during stirring and a formation of insoluble metal-phosphate was inhibited by the formation of complex ion between leached metal cation and citrate. When the slag was leached with alumina mill pot while controlling pH by nitric acid, the phosphorus dissolution ratio lowered since phosphorus ion and aluminum ion, which is supplied by the dissolution of pot and crushing ball during leaching, constructed secondary products with low solubility along with other dissolved ions.

Study of topical fluoride combined with semiconductor laser for the prevention of dental enamel caries

The prevention of dental caries is one of the main goals of modern dentistry. Other major goals include remineralization of caries, rather than the traditional "drill and fill". Remineralization is a restorative process that restores minerals and occurs daily through the presence of calcium, phosphate and fluoride in the saliva. Enamel demineralization occurs when acids produced by bacteria attack the enamel. A dynamic balance between enamel demineralization and remineralization is maintained under normal conditions, and disruption of this balance leads to progression of the lesion and eventually to cavitation formation. Fluoride plays an important role in enhancing remineralization. Topical application of fluoride is one of the most effective ways to stop or prevent dental caries. Fluoride ions can replace the hydroxyl group in hydroxyapatite, which leads to the formation of fluorapatite. The solubility of fluorapatite in acid is lower than that of hydroxyapatite. The effect of laser irradiation on the prevention of dental caries has been reported by numerous scholars. Studies have shown that when fluoride, calcium or phosphorus ions are present, laser irradiation can effectively enhance the acid resistance of tooth enamel by altering its chemical or morphological structure and promoting the remineralization process. Laser combined with fluoride has good effect and easy operation compared with other methods for caries prevention, and this paper will review the research on laser combined with fluoride in caries prevention in recent years.

Thick-walled coating in Gunn diode for measuring of electromagnetic radiation power in microwave range

In the introduction, the analysis of the physical basis for the operation of the semiconductor Gunn diode is carried out and the issues that should be resolved in substantiation of the basic physical principles of this diode operation are stated. At applied voltages of up to 0.6 V to a gallium arsenide or indium phosphide Gunn diode, free electrons appear in the conduction band of aluminum as a result of ionization of negative ions of gallium or indium atoms. At voltages from 0.6 to 2.0 V, free electrons appear in the aluminum conduction band as a result of ionization of negative ions of arsenic atoms, and at voltages from 0.6 to 3.0 V — phosphorus. The formation of negative gallium or indium ions is caused by electron capture directly from the aluminum base, while the formation of negative arsenic or phosphorus ions is mainly due to spontaneous electron transfer from the aluminum conduction band and from the negative gallium or indium ions. Electric current flows only over the surface of a gallium arsenide or indium phosphide crystal. The frequency of electric current oscillation is defined by the voltage applied to the Gunn diode and the thickness of the gallium arsenide or indium phosphide crystal. Determination of the power of microwave signals by the Gunn diode is carried out by applying a constant voltage between the cathode and the anode, which provides the frequency of current oscillation equal to the frequency of the measured microwave signal. The maximum radiation power in microwave wavelengths measured by the Gunn diode is determined by the equality of the electromagnetic wave perturbation energy and the electron affinity energy of gallium or indium atoms in the vicinity of the aluminum conduction band.

Thermal Degradation and Carbonization Mechanism of Fe-Based Metal-Organic Frameworks onto Flame-Retardant Polyethylene Terephthalate.

Currently, the metal-organic framework (MOF) is a promising candidate for flame-retardant polymers. In this study, a Fe-based MOF, MIL-88B(Fe), was introduced to polyethylene terephthalate (PET) and 3-hydroxyphenylphosphinyl-propanoic acid copolymer (P-PET) to reduce the fire hazard involved in using PET. The limiting oxygen indexes (LOIs) of MIL-PET and MIL-P-PET improved by 27% and 30%, respectively. The UL-94 level achieved for MIL-P-PET was V-0 rating. The thermal degradation and carbonization mechanisms of MIL-PET and MIL-P-PET were systematically investigated through thermogravimetric analysis coupled with a Fourier transform infrared spectroscopy (TG-IR), pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS), x-ray photoelectron spectroscopy (XPS), and Raman spectrum combined with quantum chemical molecular dynamics simulation. With the addition of MIL-88B(Fe), high graphitization and a hard flammability char residual were generated. Compared with neat PET, the ferric ions efficiently catalyzed the homolytic cleavage and dehydrogenation of PET to produce a large amount of CO2 and terephthalic acid for MIL-PET in gas phase. Rough and hierarchical char residual with ferric oxide was also generated when temperatures exceeded 600 °C. However, the carbonization process was inhibited due to the coordinated complex between phosphorus and ferric ions in MIL-P-PET, invaliding the decarboxylation and generating more benzoic acid and its precursor, which led to heavy smoke.

STRUCTURE AND PHYSICAL-MECHANICAL PROPERTIES OF ELECTROCRYSTALLISED COATINGS OF Ni−P ALLOY

The purpose of the research. Ni−P electrolytic alloy coated products are of great interest in many industries such as electronics (magnetic recording devices), oil and gas industry, medical equipment manufacturing, catalyst manufacturing. In this connection, the task of determining rational deposition modes of electrocrystallized coatings based on Ni−P alloy with increased technological and operational properties and researching their structure arises. In addition, there is a need to replace chrome electrocoatings, which, along with very high indicators of mechanical, protective and decorative properties, are obtained from toxic electrolytes that are dangerous of human life and health. Materials and methodology. In this work, electroplating of Ni−P alloy, obtained from a new electrolyte developed by us, was proposed as a replacement for chromium. Modes of obtaining high-quality electrocoating with Ni−P alloy have been identified, in which the best deposition characteristics, mechanical and decorative properties have been determined. Results. The effect of electrolysis parameters on current output, deposition rate, microhardness, surface morphology and reflectivity of electrocrystallized coatings was investigated. It was also found that the addition of phosphorus ions to the nickel plating electrolyte leads to amorphization of Ni−P alloy deposits. Scientific novelty. The influence of the deposition regime on the formation of the internal structure and surface morphology of Ni−P electrolytic coatings obtained from the electrolyte developed by the authors was studied. Conclusions. The patterns of electrodeposition of Ni−P alloy coatings were studied, and the factors influencing the formation of structure and properties were identified. It was established that the addition of phosphorus ions to the nickel plating electrolyte leads to amorphization of coatings, an increase in microhardness and reflectivity. On the basis of the analysis of the received data, the optimal conditions of electrocrystallization, under which it is possible to obtain a coating with specified physical and mechanical properties, are determined.

Consolidation of phosphorus tailings and soluble fluorine & phosphorus with calcium carbide residue-mirabilite waste as a green alkali activator

Two alkalis of industrial solid wastes, calcium carbide residue-mirabilite (CCRM), were used as a green combined activator to consolidate phosphorus tailings and soluble phosphorus as well as fluorine through the alkaline activation process. The results based on XRD, FTIR, 29Si NMR and SEM indicated that most of the blast furnace slag (BFS) forms gels to consolidate phosphorus tailings, and the calcium silicate hydrate (C-S-H) gel dominated mechanical properties and immobilization of soluble phosphorus and fluorine. Comparing with the classical alkaline activators Na2SiO3 and NaOH, the CCRM activated materials displayed great competitiveness in mechanical properties with the order of NaOH < CCRM < Na2SiO3. Its maximum compressive strength reached to 10.9 MPa, and the compressive strength increased greatly with certain increasing content of BFS. In addition, the toxicity characteristic leaching procedure (TCLP) tests found the consolidation of risky soluble fluorine and phosphorus ions in the alkaline activation materials (AAMs) presented in the trend of CCRM > NaSiO3 > NaOH, and the tendency enlarges with increasing BFS addition, over 93.1 % and 98.9 % of soluble fluorine and phosphorus ions could be well fixed. Considering on the environmental and economic efficiency, mechanical properties, soluble phosphorus and fluorine immobilization, the CCRM is found a quite potential solid waste alkali activator for phosphorus tailings and soluble fluorine & phosphorus solidification.

Experiments on Pilot-Scale Constructed Floating Wetlands Efficiency in Removing Agrochemicals.

The efficiency of constructed floating wetlands (CFWs) in their ability to remove agrochemicals (nutrients and pesticides) is here investigated in a series of pilot-scale systems. Four experimental CFWs were designed and constructed; three of them were planted with the aquatic plant species Lemna minor, Azolla pinnata and Eichhornia crassipes. The fourth did not contain any plants and was used as the control. The aim of the study was to evaluate the efficiency of CFW containing aquatic macrophytes in the reduction of pesticides and nutrients, under field conditions. The CFWs operated continuously from May 2021 to September 2021, and their removal efficiencies of nitrogen and phosphorus ions, and five commonly used pesticides were examined. The CFW systems were fed daily with agricultural wastewater which was prepared by mixing a fertilizer and predetermined doses of pesticides. The hydraulic residence time was kept at 14 days. Samples were collected on a weekly basis from both the influent and the effluent of each experimental tank, and were subsequently analyzed in the laboratory. HPLC-DAD and Ion Chromatography were implemented for sample analysis following a very simple sample preparation. Reductions for nutrient ranged from no reduction to 100% removal, whereas for pesticides these varied from no reduction to 98.8% removal, indicating that these systems can be used as efficient and low-cost pollution control technologies for agrochemical wastewater treatment. Significant reduction for certain pesticides was also observed in the algae control tank, thus, proving the efficiency of algae in organic pollution reduction, and recognizing the limitations of aquatic plant use in decontamination.

Exploration and Optimisation of High-Salt Wastewater Defluorination Process

The typical lime precipitation method is used to treat high-concentration fluorine-containing wastewater. In this way, the fluorine in the wastewater can be removed in the form of CaF2. Thus, this method has a good fluoride removal effect. In this study, calcium hydroxide was used to adjust the pH and achieve a significant fluoride removal effect at the same time. The removal rate of fluoride ion decreases gradually with the increase in the concentration of sulphate in the raw water. When the synergistic defluorination cannot meet the requirements of water production, adding a step of aluminium salt flocculation and precipitation can further reduce the fluoride ion concentration. According to the feasibility of the actual project, this study improves the lime coagulation precipitation defluorination process on this basis, and the combined process is synchronised. In the process optimisation, barium chloride is added to remove the influence of sulphate radicals in the water, and then, the pH is adjusted to 5–6. The fluoride ion concentration in high-salt wastewater can be reduced from 446.6 mg/L to 35.4 mg/L by defluorination after pre-treatment whose removal rate was 92.1%. The combined process synchronously removes fluorine and purifies the water quality to a certain extent. Indicators such as COD, total phosphorus, ammonia nitrogen, and chloride ions in wastewater are reduced, and the removal rate is increased by 35.5% under the same conditions. This scheme improves the wastewater treatment effect without increasing the existing treatment equipment. Thus, it achieves a better defluorination effect and reduces the dosage of chemicals as much as possible, which is conducive to lowering the discharge of sludge after treatment.

Environmental Remediation of Contaminated Wastewater with Ammonium Using Clay-Based Adsorbents

Due to a lack of water treatment technology, developing and emerging nations have become significant polluters and water shortage is exacerbated by pollution. Ammonium toxicity is a huge global environmental concern with no clear solution. Population growth and industrialization destroy the ecosystem. Common and industrial products contain ammonium ions. Water pollution damages fish and other aquatic life. An inexpensive and green wastewater treatment method is adsorption. Adsorbent polymers that remove ammonium ions from wastewater have been explored. Ammonium ions are very hazardous when deposited into surface waters. Surfaces of bentonite and montmorillonite clay may attach sodium ammonium ions. They are cheap and abundant, therefore used to treat drain water. Bentonite outperformed montmorillonite in eliminating ammonium ions from water. Bentonite and montmorillonite clays were used to remove residual ammonium ions. These are utilized for bentonitic and montmorillonitic clays. Both clays were absorbed in a neutral pH, and it was free of sulfuric acid, ammonium ions, and phosphorus ions. Montmorillonitic clay boosted TDS by nearly 10% whereas bentonitic clay only raised TDS by 1%. Adsorption may inexpensively filter water and the surface charge of adsorbents affect their adsorption capacity. Ammonium ions may be recycled, and several bioreactors can remove ammonium ions from liquid and solid phases. Iterate over several models and the Freundlich isotherm model outperforms the Langmuir model by 5%. And bentonite clay adsorbs better due to iron oxide content.

Study on the damage evolution of 6H-SiC under different phosphorus ion implantation conditions and annealing temperatures

In this work, we investigate the radiation damage of 6H-SiC crystals by phosphorus (P) ion implantation. The 6H-SiC samples were implanted at different energy with the same fluence of 5.0 × 1014 ions/cm2 at room temperature, one of which was subsequently annealed. Raman and absorption spectra were obtained to probe the structure and optical properties of 6H-SiC crystals after P ion implantation. In addition, Rutherford backscattering/channeling spectroscopy and transmission electron microscopy were used to explore further the damage behavior at different implantation energy and damage evolution with post-annealing treatment. It was found that the damage of the 200 keV implanted sample partially recovered after annealing at 600 °C for 60 min and disappeared at an annealing temperature of 800 °C. The damage evolution behavior of phosphorus ions implantation into 6H-SiC crystals with different implantation and annealing conditions is presented in our work.

A novel strategy to synthesize bioactive glass based on the eutectic reaction of B2O3–K2O

Melt-derived route was used to prepare modified bioactive glass-ceramic based on the 45S5 composition with the same network connectivity. Their phase composition, sinterability, and bioactivity were studied. A modified composition was proposed using potassium tetraborate (K2B4O7) to reduce the melting temperature during manufacture. The phase composition and the bioactivity was determined by X-ray diffraction and Fourier transform infrared spectroscopy. Furthermore, the antibacterial properties were evaluated against Enterococcus faecalis. The result shows that glass-ceramics already had P–O and C–O bond functional groups on day 2. These bonds are responsible for the creation of the HCA layer. Scanning electron microscopy (SEM) pictures and Energy Dispersive X-ray Spectroscopy (EDX) investigations showed that, after being immersed in SBF solution, a layer of hydroxyapatite (HA) formed on both BG surfaces on day 2 and that by day 21, HCA cluster crystals had developed. Inductively coupled plasma-optical emission spectroscopy metrics of ionic release from the prepared glass-ceramic, mainly calcium and phosphorus ions in SBF solution, revealed that HCA formation occurred on both BG surfaces, which correlated to the increasing pH within 2 days of incubation; furthermore, it exhibited good antibacterial behavior against the Enterococcus faecalis.

Resin-modified glass ionomer enriched with BIOGLASS: Ion-release, bioactivity and antibacterial effect.

Developing dental materials for the prevention of remineralization or demineralization is important for high-risk caries patients. This study aimed to evaluate the physicochemical and microbiological effects of adding 45S5 bioglass to resin-modified glass ionomer cement (RMGIC). Samples belonged to the following groups: GIC: conventional glass ionomer cement (Vitro Fil), RMGIC: resin-modified GIC (Vitro Fil LC), and RMGIC/45S5: RMGIC with 10% (wt%) of 45S5. Changes in pH and release of fluoride, calcium, and phosphorus ions under acidic (pH4) and neutral (pH7) pH conditions were evaluated. Antibacterial activity was verified based on colony-forming units. Material sorption and solubility were analyzed after bacterial exposure. After 28 days, the bioactivity of the materials was evaluated using scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Analysis of variance, post hoc Scheffe, and Tukey (α=0.05) tests were employed for statistical analysis. RMGIC/45S5 showed higher alkalization activity, calcium release at pH4 and 7, and sorption than GIC and RMGIC (p < .05). Release of phosphorus and fluoride at pH4 and 7 was higher for GIC than that for RMGIC and RMGIC/45S5 (p < .05). RMGIC/45S5 showed higher values than RMGIC (p < .05). However, antibacterial activity did not differ among the groups. Precipitates of calcium and phosphorus were visualized in RMGIC/45S5 samples via SEM/EDS. These results indicate that the RMGIC/45S5 promotes alkalization and increases the release of calcium, phosphorus, and fluoride ions, resulting in precipitate deposition rich in calcium and phosphorus, thereby being a promising option to improve the bioactivity of RMGIC.

Sedimentology of the Ediacaran barite‐bearing cap dolostone from Gaolan, northern Three Gorges, South China

AbstractWhile Ediacaran cap dolostones research is a hot topic, detailed sedimentological analysis of barite‐bearing cap dolostones remains scarce. Here, new data are presented from Xiangerwan in northern Three Gorges, South China, to illustrate the sedimentary characteristics, depositional environment and formation mechanism of the barite‐bearing cap dolostone. In ascending order, the succession is divided into: (i) pebbly dolostone; (ii) dolostone with unusual sedimentary structures (for example, sheet cracks and tepee structures); and (iii) barite‐bearing facies. The gravels of the pebbly dolostone record the slow relative sea‐level rise during post‐glacial transgression, with a local terrestrial influence. Sheet cracks and tepee structures represent water escape structures in the supratidal and upper intertidal zone, and gently wavy stromatolites in barite‐bearing facies are deposits typical of the upper intertidal zone. In addition, primary radial length‐slow dolomite cements were originally precipitated at the seafloor. In general, the cap dolostone was formed in a shallow‐water ramp environment. The form and sedimentary characteristics of barites indicate a primary (syngenetic) origin and help to divide the barites into bladed (Type I) and needle‐like (Type II) variants. With the ongoing melting of the Marinoan glacier and water density stratification, the cap dolostone was gradually precipitated, accompanied by exotic gravels input. The stratification persisted, and special sedimentary structures were widely developed. Phosphorus and barium ions were brought up from the deep basin by upwelling, indicated by the flourishing stromatolites and barite fan deposition. Above the sediment–water interface, the Type I barite first grew upward from substrates, then the Type II barite could grow either in the reverse ‘V‐shape’ cavities between and within the Type I barite clusters, forming rhythm layers with bedded dolomite, or scattered in the laminae of stromatolites or surrounding dolomite. Finally, the formation of barite fans indicates the end of cap dolostone deposition and deeper water sedimentation.

Phosphorus and Potassium Ion Dynamics in a Vertisol Soil and in Cotton Plants (Gossypium hirsutum L) During a Waterlogging Event

ABSTRACT The aim is to examine the nutrient ion dynamics in a Vertisol soil undergoing waterlogging to ascertain whether soil solution concentration and/or nutrient uptake dynamics are the cause of boll shedding in cotton. Cotton was grown in pots, and the soil waterlogged after 76 days at which time injections of 33P and 86Rb were made to trace phosphorus (P) and potassium (K) dynamics. After seven days, waterlogging in the pots were drained and an injection of 32P was made to trace P dynamics during the recovery period. Redox fell rapidly during waterlogging, and soil solution concentrations of P, K, sodium (Na), and manganese (Mn) increased. Biomass accumulation was less in the waterlogged treatment than in the non-waterlogged control. In the 7-day recovery period, shoot biomass increased in the waterlogged treatment and root biomass weight continued to decline. Recovery of 33P was 10 times higher in the control than in the waterlogged treatment during the 7-day waterlogging period treatment. Uptake of 86Rb in the control treatment was more than twice that of the waterlogged treatment during this period. Uptake of both33P and 86Rb increased during recovery but remained higher in the control treatment. Uptake of 32P occurred during post-waterlogging but remained higher in the control treatment. Reduced uptake of P and K during waterlogging is most likely due to damage to the uptake mechanisms of the roots rather than a reduction in the concentration of nutrients in the soil solution under waterlogged conditions.

Research on Corrosion Resistance and Formation Mechanism of Molybdate Composite Film

In order to reduce phosphorus pollution, the low phosphorus passivation process on Q235 steel was studied. The electrochemical method was used to test the corrosion resistance of sodium molybdate low phosphorus passivation. The polarization curve shows that the corrosion current of the sample passivated by low phosphorus is only 1/4 of that of the blank sample. Under scanning electron microscopy, the passivation film obtained by low phosphorus passivation treatment had the lowest phosphorus content and was more uniform and compact. The XPS (X-ray photoelectron spectroscopy) and OCP (open circuit potential) were used to study the film formation regularity and mechanism of low molybdenum sodium passivation. The results show that sodium molybdate low phosphorus passivation film has good corrosion resistance. The formation process of a passivation film can be divided into four stages alternating phosphating and passivation. The surface of the passivation film is mainly composed of phosphate, molybdate, molybdenum oxide, and their crystalline hydrates. The low phosphorus passivation process of sodium molybdate can reduce the concentration of phosphorus ions and reduce its pollution to the environment, which has broad application prospects.

The Salinity and Irrigation Methods Affect the Content of Macronutrients in Different Organs of Quinoa (Chenopodium quinoa Willd.)

ABSTRACT Salinity causes nutrient imbalances in plants, even in quinoa (Chenopodium quinoa Willd.), a halophyte with high nutritional value. Current investigation is a complementary study, carried out in continuation of the previous research on quinoa which illustrated that the Salinity Threshold Value (STV) of quinoa varies during different stages of its growth; it was performed in three cultivation periods, each period containing two irrigation methods (IM): i) Irrigating by ‎constant levels of ‎water salinity (ECi) (i.e. 0.3, 10, 15, 20, 25dSm−1) regardless of STV(P); and ii) Considering STV ‎at each ‎growth stage(T). Present study investigated the effect of abovementioned IMs (P, T) and ECis (i.e. 0.3, 10, 15, 20, 25dSm−1) on accumulation of nitrogen (N), phosphorus (P), and potassium (K) ions in shoots (end of vegetation) and seeds (end of seed-filling) of quinoa. Results indicated that an increase in ECi ‎from 0.3 to 25dSm−1, especially after STV, caused a 56.6% and 12.8% increase of N while a 44.3% and 27.8% decrease of P, respectively in shoot and seed of quinoa. K only showed 30.2% increase in shoot. The change of all three ions was sharper in shoot than seed due to halophytic properties of quinoa which reduces salinity influence on seed embryo. The seed of quinoa is the main source of N and protein while the shoot is rich in P and K. The T ‎method of irrigation was preferred for providing the plant chance to survive in more saline condition.