Статті в журналах: "Phosphorus oxidation state"

1

Pasek, Matthew, and Kristin Block. "Lightning-induced reduction of phosphorus oxidation state." Nature Geoscience 2, no. 8 (July 13, 2009): 553–56. http://dx.doi.org/10.1038/ngeo580.

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2

Pokrovskiy, Valeriy A. "Temperature-Programmed Desorption Mass Spectrometry (TPDMS) of Dispersed Oxides." Adsorption Science & Technology 14, no. 5 (October 1996): 301–17. http://dx.doi.org/10.1177/026361749601400505.

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Temperature-programmed desorption mass spectrometry (TPDMS) is discussed with reference to studies of modified pyrogenic oxides. Simple theoretical models are presented in order to allow an approximate analytical treatment of TPDMS data. The ‘unimolecular’ decomposition of alkoxide groups was studied. The rate constants of the reactions were derived from TPDMS measurements. The kinetics of thermal transformations of phosphorous and phosphoric acids on a pyrogenic silica surface were investigated by TPDMS. Oxidation–reduction reactions in samples containing phosphorous acid resulted in the removal of molecular phosphorus (P4). Two stages of phosphorus evolution were observed which were attributed to the disproportion of phosphorus in the surface monolayer (high-temperature stage) and in the bulk layers (low-temperature stage). The biologically active samples obtained by adsorption of cyanocobalamine, glucose and raffinose on ultrafine oxide surfaces were studied via a combination of temperature-programmed desorption and solid-state thermal analysis mass spectrometry (TPD/TA MS). The role of the charged cobalt atom and of the propionamide and benzimide groups in the adsorption mechanism is discussed. It was shown that the adsorption of cyanocobalamine on the silica surface transformed the propionamide group to a weakly bound form. TPD/TA MS data were obtained confirming the stable adsorption of glucose and raffinose on an ultrafine pyrogenic silica surface modified by amino groups.

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3

Kumar, Rakesh, Dinesh Panday, and Seema Kothari. "Kinetics and Mechanism of the Oxidation of Oxyacids of Phosphorus by Benzimidazolium Dichromate." Progress in Reaction Kinetics and Mechanism 36, no. 4 (November 2011): 352–60. http://dx.doi.org/10.3184/146867811x13103063934104.

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Oxidation of some lower oxyacids of phosphorus by benzimidazolium dichromate results in the formation of the corresponding oxyacids containing phosphorus in a higher oxidation state, via an intermediate complex formation.

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4

Oh, Kyoung Hun, Sung Won Jung, and Keun Su Kim. "Tracing the initial state of surface oxidation in black phosphorus." Applied Surface Science 504 (February 2020): 144341. http://dx.doi.org/10.1016/j.apsusc.2019.144341.

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5

Nasirov R.,, Kuspanova B.,, Kalauova A.S.,, and Satenov K.G.,. "BINDING d-ELEMENT OF THE 4TH PERIOD OF V-GROUP OF THE PERIODIC SYSTEM OF D.I. MENDELEYEV AND ITS PARAMAGNETIC PROPERTIES." SERIES CHEMISTRY AND TECHNOLOGY 5, no. 443 (October 2020): 92–98. http://dx.doi.org/10.32014/2020.2518-1491.85.

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Vanadium is a connecting element between the main subgroup VA and the subgroup VB. In the opinion of B.V. Nekrasov, if we compare the VВ group of vanadium elements with the valence states of P and Аs VА main subgroup, then in the oxidation states of -3, 0, +3 arsenic is an analogue of phosphorus, and in the oxidation state +5, it will not be an analogue of phosphorus. In contrast, in the low oxidation degrees of vanadium, it differs from phosphorus, and in the oxidation state of +5 vanadium is not a complete analogue of phosphorus. The similarity of the electronic configuration of atoms for vanadium and phosphorus in the +5 oxidation state specifies the similarity of the properties of their chemical compounds. When comparing vanadium and its compounds with elements of the VA subgroup, we conclude that vanadium is a binding element between the VA subgroup and the VB subgroup and the compounds have similar properties. As a result of many years of work, it was found that vanadium in the penta- and tetravalent states has paramagnetic properties. In crude oil, it is in a tetravalent state. In order to improve the standard photocalorimetric method for determining vanadium in oil and petroleum ashes, a more rapid method was proposed for estimating the total concentration of vanadium based on the interaction of V2O5 with concentrated hydrochloric acid. Studies of the EPR spectra of porphyrin complexes with transition metals such as copper were of great importance in the identification of natural porphyrin complexes. In the course of comparison of experimental works of paramagnetic properties of vanadium and phosphorus with each other, it can be said that their application is of great practical importance in different fields of science. Summing up the results of studying the reduction of triphenylphosphine with an alkali metal, we proposed a scheme for the splitting of triphenylphosphine, including the formation of radical anions.

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6

Waters, Jordan B., Thomas A. Everitt, William K. Myers, and Jose M. Goicoechea. "N-heterocyclic carbene induced reductive coupling of phosphorus tribromide. Isolation of a bromine bridged P–P bond and its subsequent reactivity." Chemical Science 7, no. 12 (2016): 6981–87. http://dx.doi.org/10.1039/c6sc02343f.

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Thermal treatment of a 1:1 adduct of phosphorus tribromide and 1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene (IPr) results in the formation of a reduced phosphorus-containing dimer, which can be employed to access a range of low oxidation state compounds.

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7

Ellis, Bobby D., and Charles L. B. Macdonald. "Phosphorus(I) Iodide: A Versatile Metathesis Reagent for the Synthesis of Low Oxidation State Phosphorus Compounds." Inorganic Chemistry 45, no. 17 (August 2006): 6864–74. http://dx.doi.org/10.1021/ic060186o.

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8

Goswami, Tejasbharthi Pravinbharthi, Apeksha Kadam, and Rajashree Mashru. "New Smartphone Based Colorimetric Method Development and Validation of Drugs Containing Nitrogen, Phosphorus and Sulphur." Journal of Drug Delivery and Therapeutics 12, no. 3-S (June 15, 2022): 51–63. http://dx.doi.org/10.22270/jddt.v12i3-s.5503.

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Colorimetry is a method for determining the concentration of coloured substances in a solution. The intensity of colour is directly proportional to the concentration of compound being measured. Smartphone based colorimetry has grown in popularity as analytical instruments due to their low cost and ability to collect, store and process data all in one device. In smartphone colorimetry, the camera on the phone serves as a detector. The colorimetric method based on a smartphone and the UV method both are based on the detection of colour intensity. The ammonium metavanadate is having different oxidation states and it produce different colours in its oxidation state. The +5-oxidation state shows yellow colour, +4 oxidation state shows blue colour, +3 oxidation state shows green colour and +2 oxidation state shows purple colour. The ammonium metavanadate reagent is orange red in colour; however, it transforms into green colour complex when it reacts with drugs containing nitrogen, phosphorus and sulphur in its structure. In this article the developed method for all the drugs exhibits good linearity having Correlation coefficient about 0.998(Amoxicillin trihydrate), 0.998 (Silodosin) and for 0.999(Sofosbuvir). With increasing the concentrations of API, the colour intensity increases. All photographs were taken with smartphone and analysed using the photometrix PRO software. This application converts an image to an RGB histogram and regression models are included into the photometrix PRO application. By using Photometrix PRO and UV technique, the percent RSD of for all the three drugs was Using statistical tool i.e two paired test on both procedures for all the three different drugs, the results show that both are equally significant. Keywords: UV spectrophotometry, Smartphone based colorimetry, Photometrix PRO, RGB Histogram

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9

Springett, Roger, Marzena Wylezinska, Ernest B. Cady, Mark Cope, and David T. Delpy. "Oxygen Dependency of Cerebral Oxidative Phosphorylation in Newborn Piglets." Journal of Cerebral Blood Flow & Metabolism 20, no. 2 (February 2000): 280–89. http://dx.doi.org/10.1097/00004647-200002000-00009.

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Changes in hemoglobin oxygenation and oxidation state of the CuA centre of cytochrome oxidase were measured with full spectral near infrared spectroscopy simultaneously with phosphorus metabolites using nuclear magnetic resonance 31P spectroscopy at high time resolution (10 seconds) during transient anoxia (FiO2 = 0.0 for 105 seconds) in the newborn piglet brain. During the onset of anoxia, there was no change in either phosphocreatine (PCr) concentration or the oxidation state of the CuA centre of cytochrome oxidase until there was a substantial fall in cerebral hemoglobin oxygenation, at which point the CuA centre reduced simultaneously with the decline in PCr. At a later time during the anoxia, intracellular pH decreased rapidly, consistent with a fall in cerebral metabolic rate for O2 and reduced flux through the tricarboxylic acid cycle. The simultaneous reduction of CuA and decline in PCr can be explained in terms of the effects of the falling mitochondrial electrochemical potential. From these observations, it is concluded that, at normoxia, oxidative phosphorylation and the oxidation state of the components of the electron transport chain are independent of cerebral oxygenation and that the reduction in the CuA signal occurs when oxygen tension limits the capacity of oxidative phosphorylation to maintain the phosphorylation potential.

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10

Hunt, P. G., and M. E. Poach. "State of the art for animal wastewater treatment in constructed wetlands." Water Science and Technology 44, no. 11-12 (December 1, 2001): 19–25. http://dx.doi.org/10.2166/wst.2001.0805.

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Although confined animal production generates enormous per-unit-area quantities of waste, wastewater from dairy and swine operations has been successfully treated in constructed wetlands. However, solids removal prior to wetland treatment is essential for long-term functionality. Plants are an integral part of wetlands; cattails and bulrushes are commonly used in constructed wetlands for nutrient uptake, surface area, and oxygen transport to sediment. Improved oxidation and nitrification may also be obtained by the use of the open water of marsh-pond-marsh designed wetlands. Wetlands normally have sufficient denitrifying population to produce enzymes, carbon to provide microbial energy, and anaerobic conditions to promote denitrification. However, the anaerobic conditions of wetland sediments limit the rate of nitrification. Thus, denitrification of animal wastewaters in wetlands is generally nitrate-limited. Wetlands are also helpful in reducing pathogen microorganisms. On the other hand, phosphorus removal is somewhat limited by the anaerobic conditions of wetlands. Therefore, when very high mass removals of nitrogen and phosphorus are required, pre- or in-wetland procedures that promote oxidation are needed to increase treatment efficiency. Such procedures offer potential for enhanced constructed wetland treatment of animal wastewater.

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11

Poddutoori, Prashanth, Niloofar Zarrabi, Brandon J. Bayard, Noah Holzer, Sairaman Seetharaman, Paul Karr, Francis D'Souza, and Art van der Est. "Phosphorus(V) Porphyrin: A Reductive Electron Quencher in Donor-Acceptor Systems." ECS Meeting Abstracts MA2022-01, no. 14 (July 7, 2022): 980. http://dx.doi.org/10.1149/ma2022-0114980mtgabs.

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Phosphorus(V) porphyrins hold an important place in porphyrin chemistry. The hexacoordinated phosphorus center in these porphyrins has a formal oxidation state of +5 and is, thus, extremely electron deficient. As a result, the midpoint potential for oxidation of the phosphorus(V) porphyrin is shifted to a much higher value (1.66 V for PTPP+) compared to the corresponding free-base porphyrin (1.01 V for H2TPP) or zinc(II) porphyrin (0.79 V for ZnTPP). In addition, the phosphorus center provides two axial sites for the covalently binding of substituents, allowing a greater range of possibilities for attaching donors and acceptors. By exploiting these properties several ‘axial-bonding’ type Donor-Acceptor systems have been prepared consisting of octaethylporphyrinatophosphorus(V) (POEP+) and tertaphenylporphyrinatophosphorus(V) (PTPP+) units. The unique structural topology of the octaethylporphyrinatophosphorus(V) (POEP+) and tertaphenylporphyrinatophosphorus(V) (PTPP+) enabled the construction of mono- and di-substituted phosphorus(V) porphyrin-naphthalene conjugates, respectively. Transient absorption studies revealed rapid deactivation of singlet excited phosphorus(V) porphyrin due to the reductive electron transfer process. I will present some of these examples and discuss their structural, redox, and photophysical properties. Figure 1

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12

Zhang, Zhen, Panpan Zhang, Sheng Yang, Tao Zhang, Markus Löffler, Huanhuan Shi, Martin R. Lohe, and Xinliang Feng. "Oxidation promoted osmotic energy conversion in black phosphorus membranes." Proceedings of the National Academy of Sciences 117, no. 25 (June 8, 2020): 13959–66. http://dx.doi.org/10.1073/pnas.2003898117.

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Two-dimensional (2D) nanofluidic ion transporting membranes show great promise in harvesting the “blue” osmotic energy between river water and sea water. Black phosphorus (BP), an emerging layered material, has recently been explored for a wide range of ambient applications. However, little attention has been paid to the extraction of the worldwide osmotic energy, despite its large potential as an energy conversion membrane. Here, we report an experimental investigation of BP membrane in osmotic energy conversion and reveal how the oxidation of BP influences power generation. Through controllable oxidation in water, power output of the BP membrane can be largely enhanced, which can be attributed to the generated charged phosphorus compounds. Depending on the valence of oxidized BP that is associated with oxygen concentration, the power density can be precisely controlled and substantially promoted by ∼220% to 1.6 W/m2(compared with the pristine BP membrane). Moreover, through constructing a heterostructure with graphene oxide, ion selectivity of the BP membrane increases by ∼80%, contributing to enhanced charge separation efficiency and thus improved performance of ∼4.7 W/m2that outperforms most of the state-of-the-art 2D nanofluidic membranes.

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13

Schuurman, Yves, and John T. Gleaves. "Activation of Vanadium Phosphorus Oxide Catalysts for Alkane Oxidation. The Influence of the Oxidation State on Catalyst Selectivity." Industrial & Engineering Chemistry Research 33, no. 12 (December 1994): 2935–41. http://dx.doi.org/10.1021/ie00036a007.

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14

Oh, S. G., and N. M. Rodriguez. "In situ electron microscopy studies of the inhibition of graphite oxidation by phosphorus." Journal of Materials Research 8, no. 11 (November 1993): 2879–88. http://dx.doi.org/10.1557/jmr.1993.2879.

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A combination of in situ transmission electron microscopy and thermogravimetric techniques has been used to follow the manner by which phosphorus addition to graphite influences its interaction with oxygen. Direct observation of the process shows that the additive completely inhibits the reaction at temperatures below 830 °C. At higher temperatures phosphorus species are found to bond preferentially to the graphite “armchair”{1120} faces leaving the “zigzag” {100} faces vulnerable to attack by oxygen. In situ electron diffraction analysis indicates the formation of a chemical bond between the phosphorus and graphite edge atoms at high temperatures, which involves the formation of a complex believed to become an integral part of the structure. This unique type of chemical bonding is believed to be responsible for the observed thermal stability of P–O species on the graphite atoms at temperatures up to 1050 °C. In a further series of experiments, phosphorus was found to poison the catalytic activity of cobalt, which in its unadulterated state is a very effective promoter of the graphite-oxygen reaction.

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15

Choudhary, Naresh Rajendra, Parin Choksi, and Rajashree Mashru. "New Smartphone based Colorimetric Method Development and validation for the Drugs containing Nitrogen, Sulphur and Phosphorus in Bulk and Tablet Dosage Form." Journal of Drug Delivery and Therapeutics 12, no. 3-S (June 15, 2022): 87–100. http://dx.doi.org/10.22270/jddt.v12i3-s.5510.

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A method for determining the concentration of coloured compounds in a solution is colorimetry. The intensity of the colour is related to the chemical concentration being measured. Because of their low cost and ability to collect, store, and interpret data all in one device, smartphone-based colorimetry has increased in popularity as an analytical tool. The camera on the phone is used as a detector in smartphone colorimetry. Both the smartphone colorimetric method and the UV method relied on the detection of colour intensity as concentration rose. Distinct oxidation states of ammonium metavanadate generate different colours depending on the oxidation state. The +5-oxidation state appears yellow, the +4-oxidation state appears blue, the +3-oxidation state appears green, and the +2-oxidation state appears purple. The ammonium metavanadate reagent is orange red in colour, but when it combines with pharmaceuticals that contain nitrogen, phosphorus, or sulphur in their structure, it turns green. The developed approach for all of the drugs in this article is linear. The colour intensity increases as the concentration of API increases. All of the photos were captured on a smartphone and analysed with photometrix PRO software. The photometrix PRO application turns an image to an RGB histogram, and it also includes regression models. The percent RSD for all three drugs was less than 2 employing Photometrix PRO and UV method. Using a statistical method called a two-paired test, the results reveal that both procedures are equally significant for all three drugs. Keywords: Uv spectrophotometry, Photometrix PRO, RGB Histogram, Sumatriptan Succinate, Gemifloxacin, Tenofovir disoproxil fumarate

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16

Spivakov, B. Ya, T. A. Maryutina, and H. Muntau. "Phosphorus Speciation in Water and Sediments." Pure and Applied Chemistry 71, no. 11 (November 30, 1999): 2161–76. http://dx.doi.org/10.1351/pac199971112161.

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Environmentally significant phosphorus species in water and phosphorus fractions in sediments are briefly discussed and the methods for their determination are described. One of the most critical analytical steps is the separation of the different forms which, after conversion into orthophosphates, may be determined by a multitude of various techniques. Spectrophotometric methods are often preferred for routine analysis. Several rapid automatic methods for the separation and determination of orthophosphate, linear polyphosphates, cyclic condensed phosphates and lower oxidation state anions of phosphorus, which may exist in natural and waste waters, have been developed. They are mainly based on the use of flow-injection analysis, high-performance liquid chromatography including ion chromatography, capillary electrophoresis and a few of other techniques. These methods have been described and critically evaluated.

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17

Sharma, Ritambhara, and Mangalampalli Ravikanth. "Phosphorus complexes of porphyrinoid macrocycles." Journal of Porphyrins and Phthalocyanines 20, no. 08n11 (August 2016): 895–917. http://dx.doi.org/10.1142/s1088424616500851.

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Phosphorus complexes of porphyrinoids such as porphyrins, corroles, [Formula: see text]-fused porphyrins, [Formula: see text]-fused expanded porphyrins and expanded porphyrins can be prepared readily by treating the porphyrinoid with phosphorylating agents such as PX3, PX5and POX3(X [Formula: see text] Cl or Br) under standard reaction conditions. In phosphorus porphyrinoids, the phosphorus is generally high valent [Formula: see text]5 oxidation state and the coordination number is varied from four to six. The insertion of P(V) into porphyrinoids alters the structure and electronic properties of the macrocycle significantly. Specially, the phosphorus binding mode is different from one porphyrinoid to another. The oxophilicity nature of P(V) in P(V) porphyrinoids is very useful to change variety of axial ligands and also helps to synthesize multi-porphyrin arrays by axial bonding approach. This review summarizes the phosphorus complexes of five different porphyrinoids and discusses their structure and electronic properties as well as their applications in the synthesis of more elaborate P(V) porphyrinoid based architectures.

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18

MARCOS, M., P. AMOROS, A. BELTRAN, and D. BELTRAN. "Transition metal derivatives of low oxidation state phosphorus oxoacids: synthetic pathways and structural studies." Solid State Ionics 63-65 (September 1993): 96–109. http://dx.doi.org/10.1016/0167-2738(93)90091-g.

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19

Bryant, David E., Katie E. R. Marriott, Stuart A. Macgregor, Colin Kilner, Matthew A. Pasek, and Terence P. Kee. "On the prebiotic potential of reduced oxidation state phosphorus: the H-phosphinate–pyruvate system." Chemical Communications 46, no. 21 (2010): 3726. http://dx.doi.org/10.1039/c002689a.

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20

Thomas, Ananya, Malavika Arun, Khalid Moinuddin, and Paul Joseph. "Mechanistic Aspects of Condensed- and Gaseous-Phase Activities of Some Phosphorus-Containing Fire Retardants." Polymers 12, no. 8 (August 11, 2020): 1801. http://dx.doi.org/10.3390/polym12081801.

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As a part of our ongoing investigations on passively fire protecting polymeric materials, we have been employing both reactive and additive routes involving phosphorus-containing compounds. These included inorganic and organic substances, and in the latter case, the phosphorus-bearing groups differed in terms of the chemical environments (phosphite, phosphate, phosphine, phosphine oxide and phosphonate ester) and oxidation state of the P atom (i.e., III, or V). The overall flammability profiles of wood substrates coated with the phosphorus-containing compounds were obtained through cone calorimetric measurements. The elemental composition, morphology and chemical natures of the char residues, obtained from the cone tests, were analysed through a variety of spectroscopic, chromatographic and spectrometric means. From the complementary information, obtained through these analyses, some probable mechanistic pathways that underpin the condensed- and gaseous-phase activities of the different additives are suggested. It was found that the inorganic solid additive, i.e., (NH4)2HPO4, underwent a two-step degradation, yielding ammonia gas and phosphoric acid. Furthermore, the liquid additives, owing to their volatility as compared to the solid ones, showed a relatively higher presence in the vapour phase than volatile fragments emanating from the latter ones (i.e., from phosphine and the phosphine oxides).

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21

Joseph, Paul, Malavika Arun, Stephen Bigger, Maurice Guerrieri, Doris Pospiech, and Christina Harnisch. "Mode of Action of Condensed- and Gaseous-Phase Fire Retardation in Some Phosphorus-Modified Polymethyl Methacrylate- and Polystyrene-Based Bulk Polymers." Polymers 13, no. 19 (October 3, 2021): 3402. http://dx.doi.org/10.3390/polym13193402.

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The aspects of fire retardation in some phosphorus-modified polymethyl methacrylate (PMMA) and polystyrene (PSt) polymers are reported in the present paper. Both additive and reactive strategies were employed to obtain the desired level of loading of the phosphorus-bearing compound/moiety (2 wt.% of P in each case). Test samples were obtained using bulk polymerization. The modifying compounds contained the P-atom in various chemical environments, as well as in an oxidation state of either III or V. With a view to gain an understanding of the chemical constitution of the gaseous products formed from the thermal decomposition of liquid additives/reactives, these materials were subjected to GC/MS analysis, whereas the decomposition of solid additives was detailed using the pyrolysis-GC/MS technique. Other investigations included the use of: Inductively-coupled Plasma/Optical Emission Spectroscopy (ICP/OES), solid-state NMR and FT-IR spectroscopy. In the case of PMMA-based systems, it was found that the modifying phosphonate ester function, upon thermal cracking, produced ‘phosphorus’ acid species which initiated the charring process. In the case of solid additives, it is more likely that the resultant phosphorus- and/or oxygenated phosphorus-containing volatiles acted as flame inhibitors in the gaseous phase. With the PSt-based systems, a probable process involving the phosphorylation of the phenyl groups leading to crosslinking and char formation is feasible.

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22

Andrews, J., P. Dare, G. Estcourt, D. Gapes, R. Lei, B. McDonald, and N. Wijaya. "Acetic acid recovery from a hybrid biological–hydrothermal treatment process of sewage sludge – a pilot plant study." Water Science and Technology 71, no. 5 (January 21, 2015): 734–39. http://dx.doi.org/10.2166/wst.2015.021.

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A two-stage process consisting of anaerobic fermentation followed by sub-critical wet oxidation was used to generate acetic acid from sewage sludge at pilot scale. Volatile fatty acids, dominated by propionic acid, were produced over 4–6 days in the 2,000 L fermentation reactor, which also achieved 31% solids reduction. Approximately 96% of the carbon was retained in solution over the fermentation stage. Using a 200 L wet oxidation reactor operating in batch mode, the second stage achieved 98% volatile suspended solids (VSS) destruction and 67% total chemical oxygen demand (tCOD) destruction. Acetic acid produced in this stage was recalcitrant to further degradation and was retained in solution. The gross yield from VSS was 16% for acetic acid and 21% for volatile fatty acids across the process, higher than reported yields for wet oxidation alone. The pilot plant results showed that 72% of the incoming phosphorus was retained in the solids, 94% of the nitrogen became concentrated in solution and 41% of the carbon was converted to a soluble state, in a more degradable form. Acetic acid produced from the process has the potential to be used to offset ethanol requirements in biological nutrient removal plants.

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23

Kee, Terence, David Bryant, Barry Herschy, Katie Marriott, Nichola Cosgrove, Matthew Pasek, Zachary Atlas, and Claire Cousins. "Phosphate Activation via Reduced Oxidation State Phosphorus (P). Mild Routes to Condensed-P Energy Currency Molecules." Life 3, no. 3 (July 19, 2013): 386–402. http://dx.doi.org/10.3390/life3030386.

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24

MARCOS, M. D., P. AMOROS, A. BELTRAN, and D. BELTRAN. "ChemInform Abstract: Transition Metal Derivatives of Low Oxidation State Phosphorus Oxoacids: Synthetic Pathways and Structural Studies." ChemInform 25, no. 11 (August 19, 2010): no. http://dx.doi.org/10.1002/chin.199411303.

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25

Mariappan, Thirumal, You Zhou, Jianwei Hao, and Charles A. Wilkie. "Influence of oxidation state of phosphorus on the thermal and flammability of polyurea and epoxy resin." European Polymer Journal 49, no. 10 (October 2013): 3171–80. http://dx.doi.org/10.1016/j.eurpolymj.2013.06.009.

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26

Zhou, Chunhui, Kristin Munkerup, Yuan Wang, Pradip K. Das, Priyanka Chakraborty, Jinsong Hu, Changguang Yao, Mei-Hui Huang, and Kuo-Wei Huang. "Ligand-centered reactivity of a pseudo-dearomatized phosphorus-nitrogen PN3P* rhodium complex towards molecular oxygen at room temperature." Inorganic Chemistry Frontiers 7, no. 10 (2020): 2017–22. http://dx.doi.org/10.1039/c9qi01605h.

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The pseudo-dearomatized ligand of PN³P*Rh-CO reacts with O₂ to form an α, β-unsaturated carbonyl moiety at room temperature, showcasing an unprecedented ligand-centered reactivity with the oxidation state of Rh(I) remaining untouched.

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27

Xuan, Quy Tran, Mohd Arif Anuar Mohd Salleh, Stuart D. McDonald, and Kazuhiro Nogita. "Effect of Trace Phosphorus on the Dross Formation in Tin-Copper-Nickel Wave Solder." Solid State Phenomena 273 (April 2018): 9–13. http://dx.doi.org/10.4028/www.scientific.net/ssp.273.9.

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Additions of trace elements such as Phosphorus (P) and Germanium (Ge) are common practice to improve the oxidation resistance in Tin-Copper (Sn-Cu) wave solder systems, however, little insights are available regarding their combined role. In this article, the effect of trace P (<100ppm), in the presence of Ge (<100ppm), on the phase composition and microstructure of Sn-Cu-Ni wave solder dross is studied using various techniques including Synchrotron XRPD, SEM, FIB and TEM. We find that P additions, in the presence of Ge, result in the formations of SnO, SnO2 and Ni2SnP intermetallic in the dross whereas only SnO is present in the P-free equivalent. The crystal structure of Ni2SnP is identified as orthorhombic with the space group Pnma. Based on the findings, it is evident that P not only influences the oxidation state of tin oxides but also reduces the concentration of effective Ni in the alloys via the formation of Ni2SnP intermetallic.

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28

Birke, P., and W. Weppner. "Change of the oxidation state of phosphorus in sputtered Li3±xPO4±y and Li3±xPO4±yNz films." Ionics 2, no. 1 (January 1996): 75–79. http://dx.doi.org/10.1007/bf02375872.

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29

Zhang, Qian, Xidong Hui, Zongzhen Li, Guangqiang Zhang, Jingcheng Lin, Xuelian Li, Wei Zheng, Xia Cao, and Shaoxiong Zhou. "Effect of Pre-Oxidation Treatment on Corrosion Resistance of FeCoSiBPC Amorphous Alloy." Materials 15, no. 9 (April 29, 2022): 3206. http://dx.doi.org/10.3390/ma15093206.

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In this paper, the corrosion resistance of FeCoSiBPC amorphous alloy after pre-oxidation and non-oxidation heat treatment is investigated. The corrosion behaviors of Fe80Co3Si3B10P1C3 amorphous alloys in 1 mol/L NaCl solution were investigated by the electrochemical workstation. The pre-oxidation heat treatment can improve the corrosion resistance of FeCoSiBPC amorphous alloy through an increase in the Ecorr value from −0.736 to −0.668 V, which makes it easy to reach a passive state. The corroded morphology and products of amorphous alloys were tested by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM/TEM analysis showed that, after pre-oxidation treatment, the oxide layer was divided into two layers: the inner layer was amorphous, the outer layer appeared crystalline, and the main oxide was Fe2O3. During the oxidation process, Co and P elements diffused from the inner layer to the outer layer, forming phosphorus and cobalt oxides with high corrosion resistance on the surface of the ribbon, thereby improving the corrosion resistance of the ribbon.

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30

Kaiser, Peter, and Wolfgang Jeitschko. "Preparation and Crystal Structures of the Ternary Compounds Ag2SiP2 and AuSiP." Zeitschrift für Naturforschung B 52, no. 4 (April 1, 1997): 462–68. http://dx.doi.org/10.1515/znb-1997-0406.

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Abstract The title compounds were prepared by solid state reaction of the elemental components. Their crystal structures were determined from single-crystal X-ray diffractometer data. Ag2SiP2: 14̄2d, a = 652.75(5) pm, c = 855.0(1) pm, Z = 4, R = 0.024 for 611 structure factors and 14 variable parameters; AuSiP: R3m, a = 345.9(1) pm, c = 1720.0(3) pm, Z = 3, R = 0.023 (352 F values, 11 variables). The silicon atoms in Ag2SiP2 are tetrahedrally coordinated by phosphorus atoms. The compound might therefore be considered as a phosphidosilicate and its formula can be rationalized as (Ag+1)2Si+4(P-3)2. However, Ag2SiP2 is not a tetrahedral compound since the phosphorus atoms have five near neighbors (3Ag + 2Si) and the silver atoms are coordinated by three phosphorus atoms in almost trigonal planar coordination. Weak silver-silver bonding is assumed for the shortest Ag-Ag contacts of 318 pm. In AuSiP the gold atoms are in a linear coordination of one silicon (235.5 pm) and one phosphorus atom (232.6 pm). The silicon and phosphorus atoms are tetrahedrally coordinated (3Si + 1 Au and 3P + 1 Au, respectively). Thus, the elements can be assigned oxidation numbers according to the formula Au+1Si+2P-3 . This structure was also refined in the centrosymmetric space group R3̄m, but in this improper setting the silicon and phosphorus atoms occupy one crystallographic site with random occupancy.

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31

Bond, AM, and M. Khalifa. "Accessibility of Formally Six-Coordinate Ruthenium(IV) Complexes Generated by Electrochemical Oxidation of Ruthenium(II) Dimethylglyoxime and Related Complexes Containing Phosphorus, Nitrogen or Oxygen Donor Axial Ligands." Australian Journal of Chemistry 41, no. 9 (1988): 1389. http://dx.doi.org/10.1071/ch9881389.

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The chemistry of higher valent ruthenium(IV) complexes has attracted considerable attention because of its possible relevance in catalytic processes and the fact that analogous iron complexes may be biologically important. In this work a range of RuII (N4)(X)(Y) complexes (N4 = nitrogen-based macrocycle or related ligand ; X, Y = axial ligands) has been prepared. It is shown that the presence of macrocyclic type ligands and suitable axial ligands leads to readily accessible six coordinate formally ruthenium(IV) complexes on the voltammetric time scale as ascertained by studies at platinum, gold, glassy carbon and mercury electrodes. Thus, dimethylgloxime complexes RuII ( dmgH )2(PPh3)2 and other complexes containing non- oxidizable macrocyclic type ligands readily undergo two chemically and electrochemically reversible one-electron oxidation processes to produce six coordinate ruthenium(III) and ruthenium(IV) complexes. The ruthenium(III) species are moderately stable on the synthetic time scale at ordinary temperature, whereas -78°C is required to generate low concentrations of the formally ruthenium(IV) complexes with a limited range of complexes. When the axial phosphine ligands are replaced by nitrogen and oxygen donors (N-methylimidazole , dimethyl sulfoxide , pyridine, etc.), the stability of the six-coordinate ruthenium(IV) complexes are significantly lowered as evidenced by the more complex voltammetry for the ruthenium(III)/(IV) oxidation process. Similarly, replacement of the (N4) macrocyclic type system by (N-O)2 (e.g. quinolin-8-ol as ligand ) lowers the stability of the ruthenium(IV) complexes. When the macrocyclic type ligand can itself be oxidized (e.g. benzoquinone dioxime as a ligand) four electrons can be transferred reversibly. In this case the oxidation processes are not readily assigned in terms of formal oxidation states although ruthenium(IV) still appears to be an accessible oxidation state. Electrochemical oxidation of the iron complexes, Fe( dmgH)2(P(Obu)3)2 and Fe(Pc)(P( OBu ),3)2 (Pc = phthalocyanine ), also produces two reversible one-electron oxidation processes, confirming that information derived from the more kinetically inert ruthenium systems may be applied to related iron systems on the voltammetric time scale and that macrocyclic type ligands stabilize both high oxidation state formally ruthenium(IV) and iron(IV) oxidation states.

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32

Kotake, Shinya, Hiroshi Yano, Dai Okamoto, Tomoaki Hatayama, and Takashi Fuyuki. "Improved MOS Interface Properties of C-Face 4H-SiC by POCl₃ Annealing." Materials Science Forum 679-680 (March 2011): 425–28. http://dx.doi.org/10.4028/www.scientific.net/msf.679-680.425.

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Metal-oxide-semiconductor (MOS) capacitors and MOS field-effect transistors (MOSFETs) were fabricated on C-face 4H-SiC with post-oxidation annealing in phosphorus- containing atmosphere. POCl3/N2 annealing at 1000 °C, which is an effective condition for Si-face, did not bring any improvement in the interface state density (Dit) for C-face due to additional oxide growth. We have developed a new process sequence suitable for C-face MOS structures. As a result, the Dit near the conduction band edge was drastically decreased by the developed process to less than 3x1011 cm−2eV−1. The field-effect mobility of C-face 4H-SiC MOSFETs was effectively increased to 37 cm2/Vs. We found that the incorporation of phosphorus atoms into the SiO2/SiC interface can improve MOSFET performance not only for the Si-face but also for the C-face.

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33

Lenz, Pospiech, Paven, Albach, Günther, Schartel, and Voit. "Improving the Flame Retardance of Polyisocyanurate Foams by Dibenzo[d,f][1,3,2]dioxaphosphepine 6-Oxide-Containing Additives." Polymers 11, no. 8 (July 26, 2019): 1242. http://dx.doi.org/10.3390/polym11081242.

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A series of new flame retardants (FR) based on dibenzo[d,f][1,3,2]dioxaphosphepine 6-oxide (BPPO) incorporating acrylates and benzoquinone were developed previously. In this study, we examine the fire behavior of the new flame retardants in polyisocyanurate (PIR) foams. The foam characteristics, thermal decomposition, and fire behavior are investigated. The fire properties of the foams containing BPPO-based derivatives were found to depend on the chemical structure of the substituents. We also compare our results to state-of-the-art non-halogenated FR such as triphenylphosphate and chemically similar phosphinate, i.e. 9,10-dihydro-9-oxa-10- phosphaphenanthrene-10-oxide (DOPO), based derivatives to discuss the role of the phosphorus oxidation state.

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34

Connell, J. W., J. G. Smith, and P. M. Hergenrother. "The Effect of Oxygen Plasma on Some Experimental Polymers Containing Silicon and Phosphorus." Journal of Fire Sciences 11, no. 2 (March 1993): 137–46. http://dx.doi.org/10.1177/073490419301100203.

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As part of a NASA program on high performance polymers for space applications, polymers containing silicon and phosphorus were prepared, characterized and exposed to an oxygen plasma under vacuum. Thin films of polyimides containing pendent siloxane groups, thermosetting resins contain ing silicon and poly(arylene ether)s containing phenylphosphine oxide were ex posed to a radio frequency generated oxygen plasma to assess their stability. The weight loss of the films was monitored as a function of exposure time and compared with that of Ultem® and Kapton® polyimide films of the same thick ness exposed under identical conditions. All of the experimental materials ex hibited better weight retention than either of the commercial polyimides. The thermosetting resins containing silicon and poly(arylene ether)s containing phosphine oxide exhibited only minor weight loss (0-5%) compared to that ex hibited by Ultem® (75-100%) and Kapton® (35-82%). Organic polymers con taining silicon are known to form silicates and silicon dioxide when exposed to atomic oxygen providing an in situ protective coating. Likewise, polymers con taining phosphorus have been shown to form an inorganic phosphate surface layer which subsequently provides protection from further oxidation. The same inherent characteristics that provide the polymers with atomic oxygen resis tance (i.e., high oxidation state or inorganic oxide formation) may also impart fire resistance. Materials containing phosphorus are known to exhibit good flame resistance. The chemistry, properties, limiting oxygen index and oxygen plasma resistance of these materials will be discussed.

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35

Zhu, San-E., Li-Li Wang, Hao Chen, Wei Yang, Anthony Yuen, Timothy Chen, Cheng Luo, et al. "Comparative Studies on Thermal, Mechanical, and Flame Retardant Properties of PBT Nanocomposites via Different Oxidation State Phosphorus-Containing Agents Modified Amino-CNTs." Nanomaterials 8, no. 2 (January 26, 2018): 70. http://dx.doi.org/10.3390/nano8020070.

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High-performance poly(1,4-butylene terephthalate) (PBT) nanocomposites have been developed via the consideration of phosphorus-containing agents and amino-carbon nanotube (A-CNT). One-pot functionalization method has been adopted to prepare functionalized CNTs via the reaction between A-CNT and different oxidation state phosphorus-containing agents, including chlorodiphenylphosphine (DPP-Cl), diphenylphosphinic chloride (DPP(O)-Cl), and diphenyl phosphoryl chloride (DPP(O3)-Cl). These functionalized CNTs, DPP(Ox)-A-CNTs (x = 0, 1, 3), were, respectively, mixed with PBT to obtain the CNT-based polymer nanocomposites through a melt blending method. Scanning electron microscope observations demonstrated that DPP(Ox)-A-CNT nanoadditives were homogeneously distributed within PBT matrix compared to A-CNT. The incorporation of DPP(Ox)-A-CNT improved the thermal stability of PBT. Moreover, PBT/DPP(O3)-A-CNT showed the highest crystallization temperature and tensile strength, due to the superior dispersion and interfacial interactions between DPP(O3)-A-CNT and PBT. PBT/DPP(O)-A-CNT exhibited the best flame retardancy resulting from the excellent carbonization effect. The radicals generated from decomposed polymer were effectively trapped by DPP(O)-A-CNT, leading to the reduction of heat release rate, smoke production rate, carbon dioxide and carbon monoxide release during cone calorimeter tests.

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36

Lee, H., K. M. Lee, C. H. Park, and Y. H. Park. "Application of remote monitoring and automatic control system using neural network for small wastewater treatment plants in Korea." Water Science and Technology 51, no. 10 (May 1, 2005): 249–57. http://dx.doi.org/10.2166/wst.2005.0373.

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For this study, an automatic control system has been developed by using a neural network and internet-based remote monitoring system for efficient operation of plants that have a serious variance of influent loading and have difficulties in appropriate maintenance, just like small wastewater treatment plants in Korea. In the control algorithm, ORP was used as the main sensor for control. At the point where the ORP value was judged to reach the “nitrate knee” of denitrification and phosphorus release, ORP indicated the state of lower saturation read by the neural network and then changed the operating condition from the reduction state to the oxidation state. For example, if ORP indicates the state of higher saturation at the point of “nitrogen breakpoint” or “ammonia valley” of nitrification, the neural network reads it and cuts off the oxygen supply and mixing. The dORP data have been used as one of the main input for the neural network. After the operation of lab-scale cyclic aeration process using an automatic control system, it has been found that regardless of loading variance, more than 95% of organic matters and more than 60% of nitrogen and phosphorus have been removed. Assuming that an internet-connected computer and a basic web browser are available, this study has developed a remote monitoring system that can monitor the operating status of small plants or any troubles with them.

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37

Braun, Ulrike, Aliaksandr I. Balabanovich, Bernhard Schartel, Uta Knoll, Johannes Artner, Michael Ciesielski, Manfred Döring, et al. "Influence of the oxidation state of phosphorus on the decomposition and fire behaviour of flame-retarded epoxy resin composites." Polymer 47, no. 26 (December 2006): 8495–508. http://dx.doi.org/10.1016/j.polymer.2006.10.022.

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38

Jiang, Xiaoyu, Wuxue Zhao, Wei Wang, Fan Zhang, Xiaodong Zhuang, Sheng Han, and Xinliang Feng. "One-pot approach to Pd-loaded porous polymers with properties tunable by the oxidation state of the phosphorus core." Polymer Chemistry 6, no. 35 (2015): 6351–57. http://dx.doi.org/10.1039/c5py00576k.

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39

Saito, Yoshihiro, Shigeaki Uemura, Tomohiro Kagiyama, and Ryo Toyoshima. "XPS and HAXPES analyses for pre-sputtered InP surface and InP/Pt interface." Japanese Journal of Applied Physics 61, no. 3 (March 1, 2022): 031005. http://dx.doi.org/10.35848/1347-4065/ac55e6.

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Abstract The state of the pre-sputtered indium phosphide (InP) surface was analyzed by X-ray photoelectron spectroscopy, employing synchrotron-based relatively low-energy X-ray. It was found that the pre-sputtering treatment induced the phosphorus vaporization and made the surface composition In-rich, which was thought to promote oxidation of InP surface in atmosphere. The state of the interface between InP and Pt was also investigated nondestructively, by using hard X-ray photoemission spectroscopy. As a result, it was demonstrated that the interfacial layer was composed of the native oxide (In–O, P–O) and metallic state (In–Pt or In–In, P–P) and that the pre-sputtering treatment increased significantly the amount of the P–O, In–Pt or In–In, and P–P. From a simplified calculation, assuming a Pt/In–Pt/In–P layer stacking structure and neglecting the In–O and P–O components, the thickness of the interfacial layer was estimated to be approximately 3.0 nm.

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40

Coiai, Serena, Elisa Passaglia, Simone Pinna, Stefano Legnaioli, Silvia Borsacchi, Franco Dinelli, Anna Maria Ferretti, et al. "Dispersion of Few-Layer Black Phosphorus in Binary Polymer Blend and Block Copolymer Matrices." Nanomaterials 11, no. 8 (August 3, 2021): 1996. http://dx.doi.org/10.3390/nano11081996.

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Exfoliated black phosphorus (bP) embedded into a polymer is preserved from oxidation, is stable to air, light, and humidity, and can be further processed into devices without degrading its properties. Most of the examples of exfoliated bP/polymer composites involve a single polymer matrix. Herein, we report the preparation of biphasic polystyrene/poly(methyl methacrylate) (50/50 wt.%) composites containing few-layer black phosphorus (fl-bP) (0.6–1 wt.%) produced by sonicated-assisted liquid-phase exfoliation. Micro-Raman spectroscopy confirmed the integrity of fl-bP, while scanning electron microscopy evidenced the influence of fl-bP into the coalescence of polymeric phases. Furthermore, the topography of thin films analyzed by atomic force microscopy confirmed the effect of fl-bP into the PS dewetting, and the selective PS etching of thin films revealed the presence of fl-bP flakes. Finally, a block copolymer/fl-bP composite (1.2 wt.%) was prepared via in situ reversible addition–fragmentation chain transfer (RAFT) polymerization by sonication-assisted exfoliation of bP into styrene. For this sample, 31P solid-state NMR and Raman spectroscopy confirmed an excellent preservation of bP structure.

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41

Heinicke, Joachim, Attila Dal, Hans-Friedrich Klein, Olaf Hetche, Ulrich Flörke та Hans-Jürgen Haupt. "Formation of η1-P-(2-Phosphinophenol)Ni(0)(PMe3)3 and Oxidation to cis/trans-Bis(2-phosphinophenolato)nickel(II) Complexes". Zeitschrift für Naturforschung B 54, № 10 (1 жовтня 1999): 1235–43. http://dx.doi.org/10.1515/znb-1999-1004.

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o-Phosphinophenols 1 (P⌒OH ) react with equimolar amounts of Ni(PMe3)4 at low temperatures to give yellow Ni(0) complexes such as [(HO∼P)Ni(PMe3)3] 2a with only P coordination of the P⌒OH ligand. Oxidation of solutions of 1 and Ni(PMe3)4 by dioxygen leads to brown bis(o-phosphinophenolato-P⌒O)nickel chelate complexes 3a-d. Structure elucidation by NMR is consistent with a cis-square planar geometry for 3a-c and a trans-square planar solution structure of the tert-butylphenylphosphino derivative 3d. The geometric isomers were distinguished by different ranges of phosphorus coordination shifts and 31P-13C-2 and 31P-13C-1 coupling constants. In the solid state, 3d adopts also a cis-square planar geometry. The steric stress of the substituents causes anti-orientation of the tert-butyl groups at phosphorus (R,R and S,S diastereoisomers) and a significant distorsion (22°) of the planes of the two five-membered rings. With less bulky substituents the R,S and S,R diastereoisomers are preferred as in the cis-square planar complex 3c with syn-orientation of the two isopropyl and phenyl groups, respectively.

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42

Nowak, O., G. Wandl, and K. Svardal. "Long-term experience with biological pretreatment of rendering plant effluent." Water Science and Technology 40, no. 1 (July 1, 1999): 37–44. http://dx.doi.org/10.2166/wst.1999.0009.

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At an activated sludge plant for biological pretreatment of rendering plant effluent, incomplete nitrification was repeatedly observed, despite low loading and high SRT. It is hypothesised that inadequate dosage of phosphorus leads to nutrient deficiency, although the effluent phosphate concentration was mostly above 1 mg/l. Evaluation of the ‘actual’ autotrophic maximum growth rate μ^A,T revealed a nitrification inhibition of almost 50% under the operational conditions of this plant, whereas the inhibitory effect caused by the wastewater compounds was found to be much lower. Thus, the poor performance of the nitrification process is rather generated in the plant than caused by the wastewater. Another possible reason - besides phosphorus limitation - for incomplete ammonia oxidation may be found in the anaerobic state of the pre-denitrification tank. In sludge samples from this tank, the nitrification rate was substantially reduced in some cases. At elevated temperatures, nitrification and nitrogen removal can be achieved in relatively small reactor volumes. However, several potential problems have to be considered in the operation of such plants.

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43

Poddutoori, Prashanth K., Ann Dion, Songjie Yang, Melanie Pilkington, John D. Wallis, and Art van der Est. "Light-induced hole transfer in a hypervalent phosphorus(V) octaethylporphyrin bearing an axially linked bis(ethylenedithio)tetrathiafulvalene." Journal of Porphyrins and Phthalocyanines 14, no. 02 (February 2010): 178–87. http://dx.doi.org/10.1142/s108842461000191x.

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A phosphorus(V) porphyrin bearing an axially linked bis(ethylenedithio)tetrathiafulvalene, dyad 1, and its radical cation phosphorus(V) porphyrin- O-CH2 -(bis(ethylenedithio)tetrathiafulvalene)+•, dyad 2, have been synthesized and studied as an electron hole donor-acceptor system. The absorption spectrum of dyad 1 does not show evidence for electronic coupling between the porphyrin and the bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) moieties. However, the steady-state fluorescence of the porphyrin chromophore is quantitatively quenched and its transient fluorescence lifetime is shortened compared to a reference compound in which the BEDT-TTF moiety is replaced by a methoxy group. Chemical oxidation of the BEDT-TTF moiety in dyad 1 to give dyad 2 results in recovery of the fluorescence intensity. This behavior suggests that the fluorescence quenching in dyad 1 is the result of intramolecular hole transfer from the the excited porphyrin to the BEDT-TTF moiety. The occurence of hole transfer in dyad 1 is confirmed by freeze-trapping and time-resolved electron paramagnetic resonance (EPR) measurements. The freeze-trapping EPR experiments show that steady-state irradiation of the complex leads to accumulation of its radical cation (dyad 2) while the transient EPR measurements at 5 °C show that flash irradiation of dyad 1 results in formation of a radical-ion pair with a lifetime of at least 300 ns. The triplet state of the porphyrin, which is formed by intersystem crossing and gives a strong transient EPR spectrum in the reference compound, is not observed for dyad 1. Together, the fluorescence quenching and the polarization pattern of the radical pair suggest that the hole transfer occurs from the excited singlet state of the porphyrin with high efficiency.

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44

Liu, Jiarui, Gareth Izon, Jiasheng Wang, Gilad Antler, Zhou Wang, Jie Zhao, and Matthias Egger. "Vivianite formation in methane-rich deep-sea sediments from the South China Sea." Biogeosciences 15, no. 20 (October 26, 2018): 6329–48. http://dx.doi.org/10.5194/bg-15-6329-2018.

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Abstract. Phosphorus is often invoked as the ultimate limiting nutrient, modulating primary productivity on geological timescales. Consequently, along with nitrogen, phosphorus bioavailability exerts a fundamental control on organic carbon production, linking all the biogeochemical cycles across the Earth system. Unlike nitrogen that can be microbially fixed from an essentially infinite atmospheric reservoir, phosphorus availability is dictated by the interplay between its sources and sinks. While authigenic apatite formation has received considerable attention as the dominant sedimentary phosphorus sink, the quantitative importance of reduced iron-phosphate minerals, such as vivianite, has only recently been acknowledged, and their importance remains underexplored. Combining microscopic and spectroscopic analyses of handpicked mineral aggregates with sediment geochemical profiles, we characterize the distribution and mineralogy of iron-phosphate minerals present in methane-rich sediments recovered from the northern South China Sea. Here, we demonstrate that vivianite authigenesis is pervasive in the iron-oxide-rich sediments below the sulfate–methane transition zone (SMTZ). We hypothesize that the downward migration of the SMTZ concentrated vivianite formation below the current SMTZ. Our observations support recent findings from non-steady-state post-glacial sedimentary successions, suggesting that iron reduction below the SMTZ, probably driven by iron-mediated anaerobic oxidation of methane (Fe-AOM), is coupled to phosphorus cycling on a much greater spatial scale than previously assumed. Calculations reveal that vivianite acts as an important burial phase for both iron and phosphorus below the SMTZ, sequestering approximately half of the total reactive iron pool. By extension, sedimentary vivianite formation could serve as a mineralogical marker of Fe-AOM, signalling low-sulfate availability against methanogenic and ferruginous backdrop. Given that similar conditions were likely present throughout vast swathes of Earth's history, it is possible that Fe-AOM and vivianite authigenesis may have modulated methane and phosphorus availability on the early Earth, as well as during later periods of expanded marine oxygen deficiency. A better understanding of vivianite authigenesis, therefore, is fundamental to test long-standing hypotheses linking climate, atmospheric chemistry and the evolution of the biosphere.

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45

Bryant, David E., David Greenfield, Richard D. Walshaw, Suzanne M. Evans, Alexander E. Nimmo, Caroline L. Smith, Liming Wang, Matthew A. Pasek, and Terence P. Kee. "Electrochemical studies of iron meteorites: phosphorus redox chemistry on the early Earth." International Journal of Astrobiology 8, no. 1 (January 2009): 27–36. http://dx.doi.org/10.1017/s1473550408004345.

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AbstractThe mineral schreibersite, (Fe,Ni)3P, a ubiquitous component of iron meteorites, is known to undergo anoxic hydrolytic modification to afford a range of phosphorus oxyacids. H-phosphonic acid (H3PO3) is the principal hydrolytic product under hydrothermal conditions, as confirmed here by 31P-NMR spectroscopic studies on shavings of the Seymchan pallasite (Magadan, Russia, 1967), but in the presence of photochemical irradiation a more reduced derivative, H-phosphinic (H3PO2) acid, dominates. The significance of such lower oxidation state oxyacids of phosphorus to prebiotic chemistry upon the early Earth lies with the facts that such forms of phosphorus are considerably more soluble and chemically reactive than orthophosphate, the commonly found form of phosphorus on Earth, thus allowing nature a mechanism to circumvent the so-called Phosphate Problem.This paper describes the Galvanic corrosion of Fe3P, a hydrolytic modification pathway for schreibersite, leading again to H-phosphinic acid as the key P-containing product. We envisage this pathway to be highly significant within a meteoritic context as iron meteorites are polymetallic composites in which dissimilar metals, with different electrochemical potentials, are connected by an electrically conducting matrix. In the presence of a suitable electrolyte medium, i.e., salt water, galvanic corrosion can take place. In addition to model electrochemical studies, we also report the first application of the Kelvin technique to map surface potentials of a meteorite sample that allows the electrochemical differentiation of schreibersite inclusions within an Fe:Ni matrix. Such experiments, coupled with thermodynamic calculations, may allow us to better understand the chemical redox behaviour of meteoritic components with early Earth environments.

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46

Al-Kassim, Loola S., and C. Stan Tsai. "Purification and kinetic characterization of pickerel liver alcohol dehydrogenase with dual coenzyme specificity." Biochemistry and Cell Biology 71, no. 9-10 (September 1, 1993): 421–26. http://dx.doi.org/10.1139/o93-062.

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A major alcohol dehydrogenase isozyme that displays dual coenzyme specificity has been purified from pickerel liver by ion-exchange, gel filtration, and affinity chromatographic procedures. The purified enzyme is chromatographically and electrophoretically homogeneous. It is dimeric and possesses common physical properties shared by other liver alcohol dehydrogenases. Phosphorus-31 nuclear magnetic resonance spectroscopy demonstrates that NADP+ binds to two coenzyme sites of the pickerel enzyme. Steady-state kinetic studies suggest that pickerel liver alcohol dehydrogenase catalyzes NAD(P)+-linked ethanol oxidation via a random pathway. While the NADP+ reduction involves the formation of an abortive complex at high NADP+ concentrations, the NAD+ reduction at low NAD+ concentrations follows an ordered Bi-Bi mechanism with NAD+ being the leading reactant.Key words: purification, pickerel liver, alcohol dehydrogenase.

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47

Shashulovskaya, E. A., S. A. Mosiyash, I. G. Filimonova, L. V. Grishina, and E. G. Cousina. "Hydro-chemical basis of biological productivity in the closing reservoirs of the Volga cascade." Proceedings of the Zoological Institute RAS 320, no. 3 (September 23, 2016): 367–76. http://dx.doi.org/10.31610/trudyzin/2016.320.3.367.

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Long-term dynamics of organic matter and nutrients in the closing-reservoirs of the Volga cascade in the period 2004–2014 were studied. This period was characterized by changes in climatic conditions: reduce of rainfall, increase of summer temperatures, the negative trend in water discharge of the Volga River with the pattern of decline in indicators of water availability and floods. Organic matter and nutrients can be considered as the basic characteristics of the state of the aquatic ecosystems that determine the productivity and patterns of development. Organic matter (OM) in water of the Saratov and Volgograd reservoirs was evaluated with permanganate (PO) and dichromate (COD) oxidation, BOD5. Concentrations of three forms of mineral nitrogen, mineral phosphorus, dissolved iron and silicon were analyzed. During the study period negative trends of the allochthonous organic matter, easy oxidized organic matter and major nutrients (nitrogen and phosphorus) were recorded. It was shown that a long-term decline in water runoff was the possible reason of changes in quantitative values of these hydrochemical components in the studied reservoirs. Correlation between water runoff, permanganate oxidation and nitrogen concentration indicates a role of terrigenous sources in the balance of nitrogen mineral forms. Average seasonal fluctuations of the total OM concentration, maintaining synchronicity, in the Volgograd reservoir occur at a higher level than in Saratov reservoir. We have not find changes in total OM concentrations during our study period. In the Volgograd reservoir, flow velocity deceleration and more intense heating of the water mass provide higher potential of biological production. The values of autochthonous organic matter content in the Volgograd reservoir confirm this assumption.

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48

Hao, Aimin, Sohei Kobayashi, Dong Xia, Qi Mi, Ning Yan, Mengyao Su, Aishou Lin, Min Zhao, and Yasushi Iseri. "Controlling Eutrophication via Surface Aerators in Irregular-Shaped Urban Ponds." Water 13, no. 23 (November 26, 2021): 3360. http://dx.doi.org/10.3390/w13233360.

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Surface aerators have often been introduced in urban ponds for esthetics, but their roles in remediating water quality are less understood. Effects of surface aerators on controlling eutrophication were examined in two urban ponds, in which anaerobic odors and cyanobacterial blooms had occurred and several aerators had been installed. In one of the ponds, a dramatic improvement in dissolved oxygen (DO) (from 1.8 to 8.1 mg L−1) and total phosphorus (TP) (from 1.6 to 0.4 mg L−1) was evident based on the comparison before and after the aeration. Although cyano-bloom did not occur, phytoplankton was dominated by cyanobacteria Microcystis species in both periods. Chlorophyll a (Chl-a) increased (from 29 to 51 μg L−1) and water transparency decreased (from 81 to 27 cm) after the aeration. In the other pond with an irregular shape, water quality was monitored two years after the installation to examine seasonal variation in trophic state and its spatial variation associated with aerator distribution. The water was mixed vertically well for the whole pond, as indicated by small surface-to-bottom differences in temperature. DO decreased in summer after rainfall but was always >5.7 mg L−1. Total nitrogen (TN) and TP were 0.8–2.3 and 0.03–0.07 mg L−1, respectively, and no cyano-blooms were observed across sites throughout the year. Phytoplankton was dominated by green algae and diatom species, which may be favored by the lower phosphorus level of the pond. Chl-a was higher and transparency was lower in the north side, which had more aerators and less shade from trees and buildings. These results suggest that surface aerators increased DO by vertical and horizontal mixing of water, reduced phosphorus release from sediment, and prevented cyano-bloom occurrence, but they did not improve Chl-a level and transparency. Rather, aeration can promote algal growth, and thus, additional purifying measures such as filtration and contact oxidation are required to further improve the trophic state of these ponds.

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Sin, Gürkan, David Kaelin, Marlies J. Kampschreur, Imre Takács, Bernhard Wett, Krist V. Gernaey, Leiv Rieger, Hansruedi Siegrist, and Mark C. M. van Loosdrecht. "Modelling nitrite in wastewater treatment systems: a discussion of different modelling concepts." Water Science and Technology 58, no. 6 (October 1, 2008): 1155–71. http://dx.doi.org/10.2166/wst.2008.485.

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Originally presented at the 1st IWA/WEF Wastewater Treatment Modelling Seminar (WWTmod 2008), this contribution has been updated to also include the valuable feedback that was received during the Modelling Seminar. This paper addresses a number of basic issues concerning the modelling of nitrite in key processes involved in biological wastewater water treatment. To this end, we review different model concepts (together with model structures and corresponding parameter sets) proposed for processes such as two-step nitrification/denitrification, anaerobic ammonium oxidation and phosphorus uptake processes. After critically discussing these models with respect to their assumptions and parameter sets, common points of agreement as well as disagreement were elucidated. From this discussion a general picture of the state-of-the-art in the modelling of nitrite is provided. Taking this into account, a number of recommendations are provided to focus further research and development on nitrite modelling in biological wastewater treatment.

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50

Pinchuk, Vasily A., Ion Neda, Thomas Kaukorat, Michael Farkens, Axel K. Fischer, Peter G. Jones, and Reinhard Schmutzler. "Zur Chemie der 1,3,5-Triaza-2-phosphorin-4,6-dione, Teil XIII. Darstellung und Röntgenstrukturanalyse des 1,3,5-Trimethyl-2-trichlormethyl-Derivats. Reaktionen einiger 1,3,5-Trimethyl-1,3,5-triaza-2-(R)-phosphorin-4,6-dione/Chemistry of the l,3,5-Triaza-2-phosphorine-4.6-diones, Part XIII. Synthesis and X -Ray Crystal Structure Determination of the 1,3,5-Trimethyl-2- trichlorom ethyl Derivative. Reactions of Some 1,3,5-Trimethyl-1,3,5-triaza-2-(R )-phosphorine-4,6-diones." Zeitschrift für Naturforschung B 52, no. 12 (December 1, 1997): 1510–16. http://dx.doi.org/10.1515/znb-1997-1212.

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Abstract Upon heating 1,3,5-trimethylbiuret (1) with trichloromethyldichlorophosphine in the presence of triethylamine, 2-trichloromethyl-1,3,5-trimethyl-1,3,5-triaza-2σ3λ3-phosphorine-4,6-dione (2) was obtained in good yield. Aside from NMR spectroscopic characterization, compound 2 was investigated by X-ray crystal structure analysis, representing the first case of the solid state characterization of a 2-trihalomethyl-1,3,5-trimethyl-1,3,5-triaza-2σ3λ3-phosphorine-4,6-dione derivative. The heterocycle presents an envelope conformation with phosphorus out of the plane of the other atoms. Reaction of the monochloromethyl derivative (3) corresponding to 2, with a sterically demanding azide led by oxidation of phosphorus to the stable σ4λ5-P derivative (4). 2-Hydro-1,3,5-trimethyl-1,3,5-triaza-2-oxo-2σ4λ5-phosphorine-4,6-dione (5) reacted with p-nitrobenzylidene benzylimine with formation of 6 by insertion of the C=N double bond of the imine into the P-H bond. Intramolecular hydrogen bonding in 6 was observed by 1H NMR and IR spectroscopy. Reaction of 2-(methylamino)-methyl-1,3,5-trimethyl-1,3,5-triaza-2-oxo-2σ4λ5-phosphorine-4,6-dione (7) with diethylamino-trimethylsilane led to the corresponding N-trimethylsilylated compound 8. Compound 9. bearing a peptoid group, was formed by reaction of 7 or 8 with 3-(chloroformyl)propionic acid methyl ester. The preferred method of synthesis of 9 is indicated.

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