Ozonides de phosphite source d'oxygène singulet: rendement, mécanisme

1985 ◽  
Vol 63 (11) ◽  
pp. 3203-3209 ◽  
Author(s):  
Anne Marie CaMinade ◽  
Fayez El Khatib ◽  
Max Koenig ◽  
Jean Marie Aubry
Keyword(s):  
Singlet Oxygen ◽  
High Efficiency ◽  
Lower Efficiency ◽  
Absolute Yield ◽  
The Absolute

The ozonides of several phosphites in solution in dichloromethane have been reacted with some scavengers of singlet oxygen (1O2) like rubrene (2), tetraphenylcyclopentadienone (4), and 9,10-diphenylanthracene (6). These ozonides react on the scavengers (−47 °C < t <30 °C) upon their decomposition. The Foote curves obtained by varying the respective concentrations of ozonides and of scavengers lead to parameters similar to those obtained upon the photooxidation of the scavengers by 1O2. Results confirm that these ozonides can lead to the formation of 1O2. The absolute yield of 1O2 is 100% (ρ = 1). These results also confirm the high efficiency of the rubrene toward 1O2 (γ = 1) and the lower efficiency of the tetraphenylcyclopentadienone (γ = 0.46). However, the low value (γ = 0.3) for the efficiency of the 9,10-diphenylanthracene (4) is unexpected.

scholarly journals Gene Transfer to the Desiccation-Tolerant CyanobacteriumChroococcidiopsis

2001 ◽  
Vol 183 (7) ◽  
pp. 2298-2305 ◽  
Author(s):  
Daniela Billi ◽  
E. Imre Friedmann ◽  
Richard F. Helm ◽  
Malcolm Potts
Keyword(s):  
High Efficiency ◽  
Genetic Manipulation ◽  
Recipient Cell ◽  
Conjugative Transfer ◽  
Lower Efficiency ◽  
Genetic Studies ◽  
Variable Regions ◽  
Multiple Cycles ◽  
Experimental Strain

ABSTRACT The coccoid cyanobacterium Chroococcidiopsisdominates microbial communities in the most extreme arid hot and cold deserts. These communities withstand constraints that result from multiple cycles of drying and wetting and/or prolonged desiccation, through mechanisms which remain poorly understood. Here we describe the first system for genetic manipulation ofChroococcidiopsis. Plasmids pDUCA7 and pRL489, based on the pDU1 replicon of Nostoc sp. strain PCC 7524, were transferred to different isolates of Chroococcidiopsisvia conjugation and electroporation. This report provides the first evidence that pDU1 replicons can be maintained in cyanobacteria other than Nostoc and Anabaena. Following conjugation, both plasmids replicated inChroococcidiopsis sp. strains 029, 057, and 123 but not in strains 171 and 584. Both plasmids were electroporated into strains 029 and 123 but not into strains 057, 171, and 584. Expression of P psbA-luxAB on pRL489 was visualized through in vivo luminescence. Efficiencies of conjugative transfer for pDUCA7 and pRL489 into Chroococcidiopsissp. strain 029 were approximately 10−2 and 10−4 transconjugants per recipient cell, respectively. Conjugative transfer occurred with a lower efficiency into strains 057 and 123. Electrotransformation efficiencies of about 10−4electrotransformants per recipient cell were achieved with strains 029 and 123, using either pDUCA7 or pRL489. Extracellular deoxyribonucleases were associated with each of the five strains. Phylogenetic analysis, based upon the V6 to V8 variable regions of 16S rRNA, suggests that desert strains 057, 123, 171, and 029 are distinct from the type species strain Chroococcidiopsis thermalis PCC 7203. The high efficiency of conjugative transfer of Chroococcidiopsis sp. strain 029, from the Negev Desert, Israel, makes this a suitable experimental strain for genetic studies on desiccation tolerance.

scholarly journals High-Efficiency Catalysis of Peroxymonosulfate by MgO for the Degradation of Organic Pollutants

Minerals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 2 ◽  
Author(s):  
Qian Peng ◽  
Xuekun Tang ◽  
Kun Liu ◽  
Xianping Luo ◽  
Dongsheng He ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Organic Pollutants ◽  
High Efficiency ◽  
The Novel ◽  
Ph Values ◽  
Interesting Insight ◽  
Wide Range ◽  
First Time ◽  
Insight Into ◽  
Single Factor Experiment

In the study, magnesium oxide (MgO) was used to catalyze peroxymonosulfate (PMS) for the degradation of organic pollutants for the first time. According to the single-factor experiment results, it was determined that MgO could efficiently catalyze PMS to degrade organic matters in a wide range of pH values. Based on radical quenching experiments and electron spinning resonance spectra, singlet oxygen was identified to be the crucial reactive species. Importantly, the oxygen vacancy on the surface of MgO was determined as the key active site, which accelerated the decomposition of PMS to produce singlet oxygen. This study provides an interesting insight into the novel and ignored catalyst of MgO for the highly efficient activation of PMS, which will greatly benefit the Fenton-like catalytic degradation of organic wastewater.

scholarly journals EXERGY-BASED INVESTIGATION OF A COAL-FIRED ALLAM CYCLE

2019 ◽  
Vol 137 ◽  
pp. 01018 ◽  
Author(s):  
Jing Luo ◽  
Ogechi Emelogu ◽  
Tatiana Morosuk ◽  
George Tsatsaronis
Keyword(s):  
Fossil Fuels ◽  
Coal Gasification ◽  
High Efficiency ◽  
Cycle Performance ◽  
Energetic Efficiency ◽  
Component Level ◽  
Lower Efficiency ◽  
Heating Value ◽  
Lower Heating Value ◽  
Lower Heating

Allam cycle is a novel cycle that capitalizes on the unique thermodynamic properties of supercritical CO2 and the advantages of oxy-combustion for power generation. It is a high-pressure supercritical carbon dioxide cycle designed to combust fossil fuels such as natural gas or syngas (from coal gasification systems) with complete CO2 separation at a high-efficiency and zero atmospheric emissions. This semi-closed cycle produces sequestration-ready/pipeline quality CO2 by-product, and thus eliminates the need for additional CO2-capture system. The Coal-fueled Allam cycle is targeted to deliver between 51-52% net efficiency (lower heating value) for coal gasification. In this study, the expected energetic efficiency is verified by simulating the system in Ebsilon professional software and the result showed that the net efficiency of the simulated coal-fired plant is 30.7%, which is significantly lower than the targeted value. The lower efficiency maybe as a result of the missing heat integration in the system, the high power demand of the oxidant compressor and CO2 compressors. And an exergy analysis based on published cycle data is employed, to investigate the cycle performance, identify the sources of the cycle’s thermodynamic inefficiencies at the component level; a sensitivity analysis is also performed to study the effects of selected thermodynamic parameters on the overall performance of the coal-fired Allam cycle.

scholarly journals The problem of measuring the absolute yield of 14-MeV neutrons by means of an alpha counter

1960 ◽  
Vol 7 (3) ◽  
pp. 306-314 ◽  
Author(s):  
J. Benveniste ◽  
A.C. Mitchell ◽  
C.D. Schrader ◽  
J.H. Zenger
Keyword(s):  
Absolute Yield ◽  
The Absolute

A New Type Component Mode Synthesis Beam Element Based on the Absolute Nodal Coordinate Formulation

2003 ◽  
Author(s):  
Riki Iwai ◽  
Nobuyuki Kobayashi
Keyword(s):  
High Efficiency ◽  
Absolute Nodal Coordinate Formulation ◽  
Mass Matrix ◽  
Synthesis Method ◽  
Beam Element ◽  
Component Mode Synthesis ◽  
Flexible Beam ◽  
Absolute Nodal Coordinate ◽  
New Type ◽  
The Absolute

This paper establishes a new type component mode synthesis method for a flexible beam element based on the absolute nodal coordinate formulation. The deformation of the beam element is defined as the sum of the global shape function and the analytical clamped-clamped beam modes. This formulation leads to a constant and symmetric mass matrix as the conventional absolute nodal coordinate formulation, and makes it possible to reduce the system coordinates of the beam structure which undergoes large rotations and large deformations. Numerical examples show that the excellent agreements are examined between the presented formulation and the conventional absolute nodal coordinate formulation. These results demonstrate that the presented formulation has high accuracy in the sense that the presented solutions are similar to the conventional ones with the less system coordinates and high efficiency in computation.

scholarly journals Surface Treatment on Nickel Oxide to Enhance the Efficiency of Inverted Perovskite Solar Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Kaijie Wang ◽  
Ye Tian ◽  
Heng Jiang ◽  
Meng Chen ◽  
Shuangyan Xu
Keyword(s):  
Surface Treatment ◽  
High Efficiency ◽  
Sol Gel ◽  
Perovskite Solar Cells ◽  
Hole Transport ◽  
Ozone Treatment ◽  
Lower Efficiency ◽  
Low Temperature Annealing ◽  
High Absorption Coefficient ◽  
Uv Ozone

The organic-inorganic hybrid perovskites such as CH3NH3PbI3 have been considered as one of the most promising candidates for the next-generation photovoltaic materials due to its high absorption coefficient, low exciton binding energy, and long diffusion length. Herein, we have chosen NiOx as the hole transport material because metal oxides exhibit robust properties in air. We synthesized the NiOx film by a common sol-gel method. It is found that high-temperature annealing (500°C) is required to ensure the perovskite solar cell (PSC) with an efficiency over 15%. Low-temperature annealing (100°C) cannot convert the precursor materials to fully covered NiOx film, while the PSC based on mediate-temperature annealing (300°C) NiOx has larger resistance and thus lower efficiency. Fortunately, we have found that UV-ozone treatment on the NiOx film can reduce the resistance of the device based on 300°C annealed NiOx. The champion device can reach 16% efficiency with UV-ozone-treated 300°C annealed NiOx. This work has made it possible to reduce the annealing temperature of the sol-gel NiOx for high-efficiency PSCs, and it is believed that this simple surface treatment can be further employed in other metal oxide-based optoelectronic devices.

High pressure electro-discharge singlet oxygen generator (ED SOG) with high efficiency and yield

2008 ◽  
Vol 41 (17) ◽  
pp. 172008 ◽  
Author(s):  
O V Braginsky ◽  
A S Kovalev ◽  
D V Lopaev ◽  
O V Proshina ◽  
T V Rakhimova ◽  
...  
Keyword(s):  
High Pressure ◽  
Singlet Oxygen ◽  
High Efficiency ◽  
Oxygen Generator ◽  
Singlet Oxygen Generator

scholarly journals Body composition and implications for heat production of Angus steer progeny of parents selected for and against residual feed intake

2001 ◽  
Vol 41 (7) ◽  
pp. 1065 ◽  
Author(s):  
E. C. Richardson ◽  
R. M. Herd ◽  
V. H. Oddy ◽  
J. M. Thompson ◽  
J. A. Archer ◽  
...  
Keyword(s):  
Body Composition ◽  
Chemical Analysis ◽  
Feed Intake ◽  
High Efficiency ◽  
Residual Feed Intake ◽  
Whole Body ◽  
Lower Efficiency ◽  
Fat Depots ◽  
The Difference ◽  
Low Efficiency

Yearling Angus steer progeny of parents selected for low residual feed intake (RFI; high efficiency) or high RFI (low efficiency) were evaluated for feed intake, growth and differences in body composition. RFI is the difference between actual feed intake and expected feed intake based on an animal’s size and growth over a test period. Individual intakes of a high grain content ration and growth rates were recorded for 140 days and then the steers were slaughtered for measurement of body composition. All internal organs and non-carcass fat depots were removed, weighed and ground for chemical analysis. Carcasses were kept overnight in the chiller and the left half of every carcass physically dissected into retail cuts, and then into total fat, lean and bone. Carcass fat and lean were then combined and ground for chemical analysis. Steers from low RFI parents ate less (P<0.05) than the steers from high RFI parents, for similar rates of growth. Improvement in RFI was accompanied by small changes in body composition towards greater lean and less fat in the progeny of low RFI parents. Correlations of sire estimated breeding values for RFI with end of test whole body chemical protein, chemical fat and a principal component that condensed information on fat and lean body composition at the end of the test, were statistically significant. These confirmed there was a genetic association between body composition and RFI, with fatness being associated with higher RFI (i.e. lower efficiency). However, the correlations were small and suggested that less than 5% of the variation in sire RFI was explained by variation in body composition of their steer progeny. There was no evidence that a difference in the chemical composition of gain over the test explained the greater intake of metabolisable energy (ME) by the high RFI steers. The results suggest that the difference in ME intake following a single generation of divergent selection for RFI was due to metabolic processes rather than to changes in body composition.

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