scholarly journals Time-dependent Local and Average Structural Evolution of δ-phase 239Pu-Ga Alloys

MRS Advances ◽  
2016 ◽  
Vol 1 (44) ◽  
pp. 3019-3025 ◽  
Author(s):  
Alice I. Smith ◽  
Katharine L. Page ◽  
Joan E. Siewenie ◽  
Adrian S. Losko ◽  
Sven C. Vogel ◽  
...  

ABSTRACT Plutonium metal is a very unusual element, exhibiting six allotropes at ambient pressure, between room temperature and its melting point, a complicated phase diagram, and a complex electronic structure. Many phases of plutonium metal are unstable with changes in temperature, pressure, chemical additions, or time. This strongly affects structure and properties, and becomes of high importance, particularly when considering effects on structural integrity over long periods of time [1]. This paper presents a time-dependent neutron total scattering study of the local and average structure of naturally aging δ-phase 239Pu-Ga alloys, together with preliminary results on neutron tomography characterization.

2021 ◽  
Author(s):  
Jian Qu ◽  
Xin Zhang ◽  
Zhong-Jie Wang ◽  
Shuyan Zhang ◽  
Yejian Yu ◽  
...  

Time-dependent evolutive afterglow materials can increase the security level by providing additional encryption modes in anti-counterfeiting and data encryption. The design of carbon-based materials with dynamic afterglow colors is attractive...


2013 ◽  
Vol 395-396 ◽  
pp. 637-640
Author(s):  
Yi Yang ◽  
Zheng Ping Wang ◽  
Ling Meng ◽  
Lian Jun Wang

MIL-101, a metal-organic framework material, was synthesized by the high-temperature hydrothermal method. Triethylenetetramine (TETA) modification enabled the effective grafting of an amino group onto the surface of the materials and their pore structure. The crystal structure, micromorphology, specific surface area, and pore structure of the samples before and after modification were analyzed with an X-ray diffractometer, scanning electron microscope, specific surface and aperture tester, and infrared spectrometer. The carbon dioxide adsorption properties of the samples were determined by a thermal analyzer before and after TETA modification. Results show that moderate amino modification can effectively improve the microporous structure of MIL-101 and its carbon dioxide adsorption properties. After modification, the capacity of MIL-101 to adsorb carbon dioxide decreased only by 0.61 wt%, and a high adsorption capacity of 9.45 wt% was maintained after six cycles of adsorption testing at room temperature and ambient pressure.


MRS Advances ◽  
2016 ◽  
Vol 1 (63-64) ◽  
pp. 4227-4232 ◽  
Author(s):  
S.V. Stefanovsky ◽  
O.I. Stefanovsky ◽  
M.I Kadyko ◽  
V.A. Zhachkin ◽  
L.D. Bogomolova

ABSTRACTGlasses of the series (mol.%) 40 Na2O, (20-x) Al2O3, x Fe2O3, 40 P2O5 were irradiated with 8 MeV electrons to doses equivalent of 0.1, 0.5, and 1.0 MGy and characterized by FTIR spectroscopy and ESR at room temperature. FTIR spectra of all the glasses consist of strong bands due to O-P-O stretching modes in (PO4)3- and (P2O7)4- units at 1000-1200 cm-1, P-O-P stretching modes at 900-950 cm-1 (νas) and 700-750 cm-1 (νs), and bending modes in the PO4 units. The wavenumber range lower 800 cm-1 has some contribution due to stretching modes in MO4 and MO6 (M = Al, Fe) units. Moreover the bands at 3300-3700 cm-1 and 1550-1650 cm-1 due to stretching and bending modes in both absorbed and structurally bound H2O molecules were present. As irradiation dose increases the bands due to stretching and bending modes in water molecules and M-O-H bonds become stronger and are split. No essential changes with increasing dose were observed within the spectral range of stretching modes of the O-P-O and P-O-P bonds. Irradiation yields phosphorus-oxygen hole centers - PO42- (D5) and PO42- (D6), and PO32- ion-radicals (D2) observable in ESR spectra of low-Fe glasses. At x>5 their responses are overlapped with strong broad line due to Fe(III). On the whole, with the increase in iron content the glass structural evolution decrease.


1982 ◽  
Vol 20 ◽  
Author(s):  
R. Moret ◽  
R. Comes ◽  
G. Furdin ◽  
H. Fuzellier ◽  
F. Rousseaux

ABSTRACTIn α-C5n-HNO3 the condensation of the room-temperature liquid-like diffuse ring associated with the disorder-order transition around 250 K is studied and the low-temperature. superstructure is examined.It is found that β-C8n-HNO3 exhibits an in-plane incommensurate order at room temperature.Two types of graphite-Br2 are found. Low-temperature phase transitions in C8Br are observed at T1 ≍ 277 K and T2 ≍ 297 K. The room-temperature structure of C14Br is reexamined. Special attention is given to diffuse scattering and incommensurability.


1982 ◽  
Vol 30 (4) ◽  
pp. 317-322 ◽  
Author(s):  
R E Cunningham ◽  
K S Skramstad ◽  
A E Newburger ◽  
S E Shackney

Ethanol-fixed cells stored at 4 degrees C exhibit fixation time-dependent hyperchromatism in comparison with freshly fixed cells when stained with mithramycin and examined by flow cytometry. This hyperchromatism has been found to be temperature-dependent, developing fully within 72 hr at room temperature, and within 2 hr at 37 degrees C. Cells from normal donors that are stained with mithramycin exhibit spurious aneuploid peaks. These spurious aneuploid peaks can be eliminated by incubating ethanol-fixed cells at 37 degrees C for 2 hr prior to staining; true aneuploidy is not affected by this procedure. In rare instances, cytoplasmic fluorescence can be observed in mithramycin-stained cells. In addition, unexplained hypochromatism and hyperchromatism can be observed in some clinical samples, particularly in human melanoma. The effects of these unexplained staining artifacts can be minimized or eliminated by adopting strict criteria for the clinical detection of aneuploidy by flow cytometry.


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