An in situ method on kinetics of gas hydrates

2019 ◽  
Vol 90 (3) ◽  
pp. 035111 ◽  
Author(s):  
Ali Masoudi ◽  
Parham Jafari ◽  
Masoumeh Nazari ◽  
Varun Kashyap ◽  
Bahareh Eslami ◽  
...  
2015 ◽  
Vol 128 (3) ◽  
pp. 944-947 ◽  
Author(s):  
Wei Lin ◽  
Michael Haderlein ◽  
Johannes Walter ◽  
Wolfgang Peukert ◽  
Doris Segets

2015 ◽  
Vol 55 (3) ◽  
pp. 932-935 ◽  
Author(s):  
Wei Lin ◽  
Michael Haderlein ◽  
Johannes Walter ◽  
Wolfgang Peukert ◽  
Doris Segets

2007 ◽  
Vol 56 (11) ◽  
pp. 6722
Author(s):  
Luo Yu-Feng ◽  
Zhong Cheng ◽  
Zhang Li ◽  
Yan Xue-Jian ◽  
Li Jin ◽  
...  

2002 ◽  
Vol 46 (11) ◽  
pp. 3522-3531 ◽  
Author(s):  
Peter A. Suci ◽  
Bonnie J. Tyler

ABSTRACT An in situ method for sensitive detection of differences in the action of chlorhexidine against subpopulations of cells in Candida albicans biofilms is described. Detection relies on monitoring the kinetics of propidium iodide (PI) penetration into the cytoplasm of individual cells during dosing with chlorhexidine. Accurate estimation of the time for delivery of the dosing concentration to the substratum was facilitated by using a flow cell system for which transport to the interfacial region was previously characterized. A model was developed to quantify rates of PI penetration based on the shape of the kinetic data curves. Yeast were seeded onto the substratum, and biofilm formation was monitored microscopically for 3 h. During this period a portion of the yeast germinated, producing filamentous forms (both hyphae and pseudohyphae). When the population was subdivided on the basis of cell morphology, rates of PI penetration into filamentous forms appeared to be substantially higher than for yeast forms. Based on the model, rates of penetration were assigned to individual cells. These data indicated that the difference in rates between the two subpopulations was statistically significant (unpaired t test, P < 0.0001). A histogram of rates and analysis of variance indicated that rates were approximately equally distributed among different filamentous forms and between apical and subapical segments of filamentous forms.


2003 ◽  
Vol 81 (1-2) ◽  
pp. 503-518 ◽  
Author(s):  
A Klapproth ◽  
E Goreshnik ◽  
D Staykova ◽  
H Klein ◽  
W F Kuhs

An overview of recent structural work focusing on the gas hydrates of methane and carbon dioxide is given. Both the crystal structure and the microstructure are considered. We report on the pressure-dependent molecular structure of methane clathrate hydrate using laboratory-made hydrogenous and deuterated samples investigated by neutron and hard-X-ray synchrotron diffraction experiments. The isothermal compressibilities are determined for hydrogenated and deuterated CH4 hydrate, and isotopic differences between both compounds are established for the first time. The cage filling of carbon dioxide and methane hydrate is determined and compared with predictions from statistical thermodynamic theory. In the case of small cages in methane hydrate, experimental results and predictions do not agree. Field-emission scanning electron microscopy reveals the meso- to macro-porous nature of gas hydrates formed with an excess of free gas. Furthermore, in situ measurements of the formation kinetics of porous hydrates are reported in which differences between methane and carbon dioxide are established quantitatively and the transient existence of a type II carbon dioxide structure is found. PACS Nos.: 82.75-z, 61.10Nz, 61.12Ld, 68.37Hk


Author(s):  
J. Drucker ◽  
R. Sharma ◽  
J. Kouvetakis ◽  
K.H.J. Weiss

Patterning of metals is a key element in the fabrication of integrated microelectronics. For circuit repair and engineering changes constructive lithography, writing techniques, based on electron, ion or photon beam-induced decomposition of precursor molecule and its deposition on top of a structure have gained wide acceptance Recently, scanning probe techniques have been used for line drawing and wire growth of W on a silicon substrate for quantum effect devices. The kinetics of electron beam induced W deposition from WF6 gas has been studied by adsorbing the gas on SiO2 surface and measuring the growth in a TEM for various exposure times. Our environmental cell allows us to control not only electron exposure time but also the gas pressure flow and the temperature. We have studied the growth kinetics of Au Chemical vapor deposition (CVD), in situ, at different temperatures with/without the electron beam on highly clean Si surfaces in an environmental cell fitted inside a TEM column.


Author(s):  
R-R. Lee

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.


Author(s):  
M. Park ◽  
S.J. Krause ◽  
S.R. Wilson

Cu alloying in Al interconnection lines on semiconductor chips improves their resistance to electromigration and hillock growth. Excess Cu in Al can result in the formation of Cu-rich Al2Cu (θ) precipitates. These precipitates can significantly increase corrosion susceptibility due to the galvanic action between the θ-phase and the adjacent Cu-depleted matrix. The size and distribution of the θ-phase are also closely related to the film susceptibility to electromigration voiding. Thus, an important issue is the precipitation phenomena which occur during thermal device processing steps. In bulk alloys, it was found that the θ precipitates can grow via the grain boundary “collector plate mechanism” at rates far greater than allowed by volume diffusion. In a thin film, however, one might expect that the growth rate of a θ precipitate might be altered by interfacial diffusion. In this work, we report on the growth (lengthening) kinetics of the θ-phase in Al-Cu thin films as examined by in-situ isothermal aging in transmission electron microscopy (TEM).


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