Low-temperature interface structure ofCaF2/Si(111)studied by combining x-ray standing waves with component-resolved photoemission

Low temperature x-ray microanalysis (LTXM) of solid biological materials has been documented for Lemna minor L. root tips. This discussion will be limited to a demonstration of LTXM for measuring relative elemental distributions of P,S,Cl and K species within whole cells of tobacco leaves.Mature Wisconsin-38 tobacco was grown in the greenhouse at the University of California, Berkeley and picked daily from the mid-stalk position (leaf #9). The tissue was excised from the right of the mid rib and rapidly frozen in liquid nitrogen slush. It was then placed into an Amray biochamber and maintained at 103K. Fracture faces of the tissue were prepared and carbon-coated in the biochamber. The prepared sample was transferred from the biochamber to the Amray 1000A SEM equipped with a cold stage to maintain low temperatures at 103K. Analyses were performed using a tungsten source with accelerating voltages of 17.5 to 20 KV and beam currents from 1-2nA.

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Bulk standards for low-temperature biological x-ray microanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111525 ◽

1984 ◽

Vol 42 ◽

pp. 282-283

Author(s):

P. Echlin ◽

M. McKoon ◽

E.S. Taylor ◽

C.E. Thomas ◽

K.L. Maloney ◽

...

Keyword(s):

Phase Separation ◽

Low Temperature ◽

Analytical Method ◽

Salt Solutions ◽

Absolute Concentration ◽

Cooling Process ◽

X Ray ◽

The Absolute ◽

Analytical Procedures ◽

Electrical Conductors

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.

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X-ray standing waves—a new method of studying the structure of crystals

Uspekhi Fizicheskih Nauk ◽

10.3367/ufnr.0149.198605c.0069 ◽

1986 ◽

Vol 149 (05) ◽

pp. 69-103 ◽

Cited By ~ 60

Author(s):

M.V. Koval'chuk ◽

V.G. Kohn

Keyword(s):

Standing Waves ◽

New Method ◽

X Ray

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Micro X-Ray Diffraction Study of Polycrystalline MgB 2 Wire and Evaluation of Carbon Doping Effect Via Low-Temperature Sintering

SSRN Electronic Journal ◽

10.2139/ssrn.3474468 ◽

2019 ◽

Author(s):

Minoru Maeda ◽

Dipak Patel, Dr. ◽

Hiroaki Kumakura, Dr. ◽

Gen Nishijima, Dr. ◽

Akiyoshi Matsumoto, Dr. ◽

...

Keyword(s):

Low Temperature ◽

Diffraction Study ◽

Carbon Doping ◽

Doping Effect ◽

Low Temperature Sintering ◽

X Ray Diffraction ◽

X Ray

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ChemInform Abstract: ELECTRON DISTRIBUTION IN μ-ACETYLENE-BIS(CYCLOPENTADIENYLNICKEL) BY LOW-TEMPERATURE X-RAY DIFFRACTION

Chemischer Informationsdienst ◽

10.1002/chin.197630068 ◽

1976 ◽

Vol 7 (30) ◽

pp. no-no

Author(s):

Y. WANG ◽

P. COPPENS

Keyword(s):

Low Temperature ◽

Electron Distribution ◽

X Ray Diffraction ◽

X Ray

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The Application of X-Ray Diffraction at Elevated Temperatures to Study the Mechanism of Formation of Sodium Tripolyphosphate

Advances in X-ray Analysis ◽

10.1154/s0376030800001634 ◽

1961 ◽

Vol 5 ◽

pp. 276-284

Author(s):

E. L. Moore ◽

J. S. Metcalf

Keyword(s):

High Temperature ◽

Low Temperature ◽

Amorphous Phase ◽

Elevated Temperatures ◽

Sodium Tripolyphosphate ◽

X Ray Diffraction ◽

Mechanism Of Formation ◽

X Ray ◽

Temperature Form ◽

High Temperature Form

AbstractHigh-temperature X-ray diffraction techniques were employed to study the condensation reactions which occur when sodium orthophosphates are heated to 380°C. Crystalline Na4P2O7 and an amorphous phase were formed first from an equimolar mixture of Na2HPO4·NaH2PO4 and Na2HPO4 at temperatures above 150°C. Further heating resulted in the formation of Na5P3O10-I (high-temperature form) at the expense of the crystalline Na4P4O7 and amorphous phase. Crystalline Na5P3O10-II (low-temperature form) appears after Na5P3O10-I.Conditions which affect the yield of crystalline Na4P2O7 and amorphous phase as intermediates and their effect on the yield of Na5P3O10 are also presented.

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Low Temperature Water-Gas Shift: Enhancing Stability through Optimizing Rb Loading on Pt/ZrO2

Catalysts ◽

10.3390/catal11020210 ◽

2021 ◽

Vol 11 (2) ◽

pp. 210

Author(s):

Caleb Daniel Watson ◽

Michela Martinelli ◽

Donald Charles Cronauer ◽

A. Jeremy Kropf ◽

Gary Jacobs

Keyword(s):

Low Temperature ◽

Hydrogen Transfer ◽

Water Gas Shift ◽

Significant Shift ◽

Catalyst Activation ◽

X Ray ◽

Temperature Programmed ◽

Water Gas ◽

X Ray Absorption ◽

Temperature Water

Recent studies have shown that appropriate levels of alkali promotion can significantly improve the rate of low-temperature water gas shift (LT-WGS) on a range of catalysts. At sufficient loadings, the alkali metal can weaken the formate C–H bond and promote formate dehydrogenation, which is the proposed rate determining step in the formate associative mechanism. In a continuation of these studies, the effect of Rb promotion on Pt/ZrO2 is examined herein. Pt/ZrO2 catalysts were prepared with several different Rb loadings and characterized using temperature programmed reduction mass spectrometry (TPR-MS), temperature programmed desorption (TPD), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), an X-ray absorption near edge spectroscopy (XANES) difference procedure, extended X-ray absorption fine structure spectroscopy (EXAFS) fitting, TPR-EXAFS/XANES, and reactor testing. At loadings of 2.79% Rb or higher, a significant shift was seen in the formate ν(CH) band. The results showed that a Rb loading of 4.65%, significantly improves the rate of formate decomposition in the presence of steam via weakening the formate C–H bond. However, excessive rubidium loading led to the increase in stability of a second intermediate, carbonate and inhibited hydrogen transfer reactions on Pt through surface blocking and accelerated agglomeration during catalyst activation. Optimal catalytic performance was achieved with loadings in the range of 0.55–0.93% Rb, where the catalyst maintained high activity and exhibited higher stability in comparison with the unpromoted catalyst.

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