Ring Fragmentation Approaches to Low-Coordinate Phosphorus Species

Author(s):  
L. D. Quin ◽  
S. Jankowski ◽  
G. S. Quin ◽  
A. Sommese ◽  
J.-S. Tang ◽  
...  
Keyword(s):  
2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Qing Xu ◽  
Xiaoping Yu ◽  
Yafei Guo ◽  
Tianlong Deng ◽  
Yu-Wei Chen ◽  
...  

Overlying sediment and pore waters were collected in summer and winter at upstream (Jintang) and downstream (Neijiang) sites of the Tuohe River, which is one of the five largest tributaries of the Yangtze River in China. Phosphorus species, including soluble reactive phosphorus (SRP), soluble unreactive phosphorus (SUP), and total dissolved phosphorus (TDP), and some diagenetic constituents including dissolved Fe(II), Mn(II), and sulfide in overlying and pore waters, were measured systematically. The seasonal variations and vertical distributions of phosphorus species in overlying and pore waters at both sampling sites were obtained to elucidate some aspects of the transport and transformations of phosphorus. Based on the profiles of pore and overlying waters as well as the TDN/TDP data during an algal bloom in 2007, it was clearly demonstrated that phosphorus was the main factor limiting the phytoplankton growth in the Tuohe River.


2005 ◽  
Vol 891 ◽  
Author(s):  
Ronald A. Arif ◽  
Nam-Heon Kim ◽  
Luke J. Mawst ◽  
Nelson Tansu

ABSTRACTSelf-assembled InGaAs quantum dots (QD) grown by metal organic chemical vapor deposition (MOCVD) have a natural peak emission wavelength around 1150-1200-nm due to its specific composition, shapes, and sizes. In this work, a new method to engineer the emission wavelength capability of MOCVD-grown InGaAs QD on GaAs to ∼1000-nm by utilizing interdiffused InGaAsP QD has been demonstrated. Incorporation of phosphorus species from the GaAsP barriers into the MOCVD-grown self-assembled InGaAs QD is achieved by interdiffusion process. Reasonably low threshold characteristics of ∼ 200-280 A/cm2 have been obtained for interdiffused InGaAsP QD lasers emitting at 1040-nm, which corresponds to blue-shift of ∼ 85-90-nm in comparison to that of unannealed InGaAs QD laser.


2012 ◽  
Vol 124 (33) ◽  
pp. 8455-8458 ◽  
Author(s):  
Alexander S. Ivanov ◽  
Andrew J. Morris ◽  
Konstantin V. Bozhenko ◽  
Chris J. Pickard ◽  
Alexander I. Boldyrev

1999 ◽  
Vol 71 (11) ◽  
pp. 2161-2176 ◽  
Author(s):  
B. Ya. Spivakov ◽  
T. A. Maryutina ◽  
H. Muntau

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.


Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 645
Author(s):  
Junlie Zhou ◽  
Mengran Du ◽  
Jiwei Li ◽  
Hengchao Xu ◽  
Kaiwen Ta ◽  
...  

Phosphorus (P) is an important nutrient for biological communities in cold seeps. However, our knowledge on the source, species, and cycling of P in cold seep environments is limited. In this study, the concentration, species, and micro to nanometer scale distribution of P in seep carbonates were examined at three deep-sea cold seeps in the South China Sea and East China Sea. The Ca-P accounts for the largest proportion of P—followed by detrital-P, Fe-P, organic-P, and exchangeable-P. The distribution patterns of Ca-P, detrital-P, and organic-P in the seep carbonates differ from one another, as shown by elemental mapping with NanoSIMS and scanning electron microscopy. The covariation of P with Ca and C reveals that Ca-P co-precipitates with Ca-carbonate, which is linked to the process of sulfate-driven anaerobic oxidation of methane. Organic-P is also observed within biofilm-like organic carbon aggregates, revealing the microbial enrichment of P by fluids in the process of anaerobic oxidation of methane. P with a granulated morphology was identified as detrital-P derived from deep sediments. Most importantly, it is evident that Ca-P is positively correlated to the Fe content in all the seep carbonates. This indicates the likelihood that the dissolved P in cold-seep fluids is released primarily from Fe oxides through Fe-driven anaerobic oxidation of methane in deep sediments. These processes associated with different species of P may have significant implications for P geochemical cycling and anaerobic oxidation of methane impelled by Fe and sulfate reduction in cold seep environments.


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