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2000

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Articles 2491 - 2520 of 2647

Full-Text Articles in Physical Sciences and Mathematics

Nebraska Information, Number Of Topographical Maps Per County, University Of Nebraska - Lincoln Jan 2000

Nebraska Information, Number Of Topographical Maps Per County, University Of Nebraska - Lincoln

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Overland Trails, University Of Nebraska - Lincoln Jan 2000

Overland Trails, University Of Nebraska - Lincoln

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Nebraska Map Of Counties, Conservation And Survey Division Jan 2000

Nebraska Map Of Counties, Conservation And Survey Division

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Distribution And Thickness Of Glacial Till In Nebraska. Jan 2000

Distribution And Thickness Of Glacial Till In Nebraska.

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Metric System Vs. Inch-Pound Units Jan 2000

Metric System Vs. Inch-Pound Units

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Chase County Test Hole Logs, Vincent H. Dreeszen Jan 2000

Chase County Test Hole Logs, Vincent H. Dreeszen

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Dakota County Test Hole Logs, Raymond R. Burchett, Frank A. Smith Jan 2000

Dakota County Test Hole Logs, Raymond R. Burchett, Frank A. Smith

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Custer County Test Hole Logs, Larry D. Cast Jan 2000

Custer County Test Hole Logs, Larry D. Cast

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Gosper County Test Hole Logs, Larry D. Cast Jan 2000

Gosper County Test Hole Logs, Larry D. Cast

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Garden County Test Hole Logs, Frank A. Smith Jan 2000

Garden County Test Hole Logs, Frank A. Smith

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Kimball County Test Hole Logs, Frank A. Smith Jan 2000

Kimball County Test Hole Logs, Frank A. Smith

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Preliminary Results Of Bitumen And Whole-Rock Elemental Analyses Of Crp-2/2a, Victoria Land Basin, Antarctica, Richard Kettler, E. Papastavros Jan 2000

Preliminary Results Of Bitumen And Whole-Rock Elemental Analyses Of Crp-2/2a, Victoria Land Basin, Antarctica, Richard Kettler, E. Papastavros

Department of Earth and Atmospheric Sciences: Faculty Publications

Sediments and rocks recovered in CRP-2/2A coring operations contain relatively little organic matter (average TOC=0.28%) and very small amounts of solvent-soluble organic matter. Because Early Oligocene sediment included significant amounts of coal detritus, TOC values are higher in Early Oligocene rocks than in younger rocks. TOC values are highest in the fine-grained rocks deposited as part of the highstand systems tract (HST) and TOC values decrease from the bottom to the top of the HST. The TOC:TN ratios observed in the CRP-2/2A core typically exceed 10, and are strong evidence that the preserved organic matter comprises a mixture of detrital …

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Laser-Derived, Particle Size Data From Crp-2/2a: Implications For Sequence And Seismic Stratigraphy, K J. Woolfe, L K. Stewart, Christopher R. Fielding, M Lavelle Jan 2000

Laser-Derived, Particle Size Data From Crp-2/2a: Implications For Sequence And Seismic Stratigraphy, K J. Woolfe, L K. Stewart, Christopher R. Fielding, M Lavelle

Department of Earth and Atmospheric Sciences: Faculty Publications

Gravel-free, high-resolution (1-metre spacing, 32 channel) particle size data from the CRP-2/2A drill core indicate that many of the diamictites were likely deposited from floating ice. Textural dislocations occur at most sequence boundaries and provide independent corroboration of the sequence stratigraphic interpretation. Likewise the data largely support the correlation drawn (Fielding et al., this volume) between the sequence stratigraphic cycles and the regional seismic stratigraphy (an alternative correlation to Reflector ‘f’ is also suggested). The gravel-free data appear to be reflecting predominantly regional (global?) forcing with some possible local effects, and long-term trends persisting through gravelly textural dislocations.

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Morphology And Taxonomic Position Of The Late Cretaceous Diatom Genus Pomphodiscus Barker & Meakin, Vladimir A. Nikolaev, David M. Harwood Jan 2000

Morphology And Taxonomic Position Of The Late Cretaceous Diatom Genus Pomphodiscus Barker & Meakin, Vladimir A. Nikolaev, David M. Harwood

Department of Earth and Atmospheric Sciences: Faculty Publications

Results from our investigation of Upper Cretaceous diatoms from the Marca Shale Member of the Moreno Shale in California and from Ocean Drilling Program (ODP) Hole 748C on the Kerguelen Plateau ,Southern Indian Ocean enable a clarification of the taxonomic position of several diatoms. Differences in areola structure ,a primary and conservative character of the diatom valve, are used to separate diatoms recently included in the genus Benetorus. We resurrect he genus Pomphodiscusto include species with locular areolae, a central rimoportula ,and a central inflated chamber .We propose the new species Pomphodiscusk erguelensisn. sp. and new combination Pomphodiscusc …

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Oligocene And Lower Miocene Siliceous Microfossil Biostratigraphy Of Cape Roberts Project Core Crp-2/2a, Victoria Land Basin, Antarctica, R. Scherer, S. M. Bohaty, David M. Harwood Jan 2000

Oligocene And Lower Miocene Siliceous Microfossil Biostratigraphy Of Cape Roberts Project Core Crp-2/2a, Victoria Land Basin, Antarctica, R. Scherer, S. M. Bohaty, David M. Harwood

Department of Earth and Atmospheric Sciences: Faculty Publications

Marine diatoms are the primary biostratigraphical and palaeoenvironmental tool for interpreting the upper Palaeogene and lower Neogene strata recovered during the second drilling season of the Cape Roberts Project at site CRP-2 in the western Ross Sea, Antarctica. Silicoflagellates, ebridians, and a chrysophyte cyst provide supporting biostratigraphical information. More than 100 dominantly planktic diatom taxa are recognised. Of these, more than 30 are treated informally, pending SEM examination and formal description. Many other taxa are noted only to generic level. Lower Oligocene (c. 31Ma) through lower Miocene (c. 18.5 Ma) diatoms occur from 28 mbsf down to 565 …

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Nutrients As A Link Between Ionic Concentration/Composition And Diatom Distributions In Saline Lakes, J. E. Saros, Sherilyn C. Fritz Jan 2000

Nutrients As A Link Between Ionic Concentration/Composition And Diatom Distributions In Saline Lakes, J. E. Saros, Sherilyn C. Fritz

Department of Earth and Atmospheric Sciences: Faculty Publications

Diatom profiles in closed-basin lake sediments are commonly used to reconstruct climate change based on the observed correlations between salinity (ionic concentration) and modern diatom assemblages. Diatom assemblages are strongly correlated not only with salinity but also anion composition, with certain taxa characteristic of carbonate systems and others sulfate-dominated waters. Although strong correlations exist, the actual mechanisms behind these correlations are unknown. Here we briefly review the influence of salinity and ionic composition on nutrient dynamics in saline lakes and suggest that these interactions may drive shifts in diatom species composition along gradients of ionic concentration/ composition. We discuss the …

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Clay Mineral Composition Of Glacial Erratics, Mcmurdo Sound, Mary Anne Holmes Jan 2000

Clay Mineral Composition Of Glacial Erratics, Mcmurdo Sound, Mary Anne Holmes

Department of Earth and Atmospheric Sciences: Faculty Publications

Twenty-two erratics collected from coastal moraines along the shores of Mount Discovery, Brown Peninsula, Minna Bluff, on Black Island, and from the Salmon and Miers valley floors in East Antarctica were examined for their mineral composition in the <2 m fraction by x-ray diffraction to determine their provenance and the climate under which the sediment in the erratics formed. Semi-quantitative results from peak areas were subjected to principal components analysis and indicate that there are two distinct mineral compositions in the erratics (C = 0.05): A) dominant smectite group minerals, minor illite and kaolinite, and no chlorite, and B) dominant illite, subordinate smectite group, and either chlorite and R=l US clay or R=3 US clay. Group A erratics include two types: 1) Eocene age siliciclastic sediment and 2) volcaniclastics of unknown age. Group B erratics comprise three types: 1) Eocene age siliciclastic sediment dominated by illite with subordinate smectite, no chlorite, and very low levels of kaolinite and mixed-layer clays; 2) post Eocene age erratics dominated by illite with a major component of chlorite and R=l US clay, minor or no smectite and kaolinite; and 3) post Eocene age erratics dominated by illite and containing R=3 US clay. Eocene age sediment occurs in either group and so had two distinct provenances for the clay fraction: a smectite-dominant area and an illite-rich, smectite-poor area. Post Eocene age sediment also had two distinct provenances for the clay fraction and are different from the Eocene sources: a metamorphic + ancient sedimentary terrain that supplied chlorite, illite, and R=l US clay to some of the erratics, and a sedimentary terrain that supplied illite and R=3 US clay. Kaolinite levels are low, indicating the absence of intense weathering and/or any significant contribution from the Beacon Supergroup.

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Isotopic Signature Of Burial Diagenesis And Primary Lithological Contrasts In Periplatform Carbonates (Miocene, Great Bahama Bank), Tracy D. Frank, Karin Bernet Jan 2000

Isotopic Signature Of Burial Diagenesis And Primary Lithological Contrasts In Periplatform Carbonates (Miocene, Great Bahama Bank), Tracy D. Frank, Karin Bernet

Department of Earth and Atmospheric Sciences: Faculty Publications

The stable isotope geochemistry of Miocene sediments from the leeward margin of the Great Bahama Bank was examined to investigate burial diagenetic processes in periplatform carbonates. Data indicate that, in addition to differences in bulk proportions of neritic and pelagic carbonate along the slope, rhythmic variation in primary carbonate content has controlled patterns of burial diagenesis and associated geochemical signatures throughout much of the succession examined. The present study focuses on Ocean Drilling Program Sites 1006 and 1007, the most distal of five sites drilled from marginal to deep basin environments during Leg 166. These Miocene sections are characterized by …

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Enhanced Three-Dimensional Reconstruction Of Surfaces Using Multicolor Gratings, Bernard S. Gilbert, Joel H. Blatt Jan 2000

Enhanced Three-Dimensional Reconstruction Of Surfaces Using Multicolor Gratings, Bernard S. Gilbert, Joel H. Blatt

Aerospace, Physics, and Space Science Faculty Publications

Most optical topolography systems use a single-wavelength laser for projection, using a swept spot, a moving line, or a projected grating. In a typical projected grating system, the gratings are shifted and a series of images is used to recover the 3-D shape of the target. When the series of images is analyzed in the normal phase shift manner, the resulting 2-D phase map typically has phase unwrapping problems due to noise and Nyquist limits. Surfaces with large vertical discontinuities present a problem for phase unwrapping 3-D shape recovery. We look at simultaneously projecting multiple wavelengths onto a surface to …

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Applicability Of Ozone In Small Drinking Water Systems, Craig D. Adams, Justin Sutherland Jan 2000

Applicability Of Ozone In Small Drinking Water Systems, Craig D. Adams, Justin Sutherland

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The use of ozone in water treatment plants is expanding rapidly in the United States. Ozone offers excellent disinfection properties (including chlorine-resistant pathogens) and does not form trihalomethanes. Additionally, ozone can be used to achieve or control many other water quality parameters such as color, taste and odor, and inorganic and organic contaminant concentrations. Control of ozone's disinfection byproducts such as bromate (formed in high bromide waters) is required. This presentation will review the synergistic effects of ozone applicable to use in small water treatment plants.

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Textured Mos 2 Thin Films Obtained On Tungsten: Electrical Properties Of The W/Mos 2 Contact, E. Gourmelon, J. C. Bernède, J. Pouzet, S. Marsillac Jan 2000

Textured Mos 2 Thin Films Obtained On Tungsten: Electrical Properties Of The W/Mos 2 Contact, E. Gourmelon, J. C. Bernède, J. Pouzet, S. Marsillac

Electrical & Computer Engineering Faculty Publications

Textured films of molybdenum disulfide have been obtained by solid state reaction between the constituents in thin films form when a (200) oriented tungsten sheet is used as substrate. The crystallites have their c axis perpendicular to the plane of the substrate. The annealing conditions are T=1073K and t=30 min. The films are stoichoimetric and p type. Such highly textured films are achieved without foreign atom addition (Ni, Co...). It appears, as shown by x-ray photoelectron spectroscopy, that a thin WS2 layer is present at the interface W/MoS2. The crystallization process is discussed by a …

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Determination Of Thermal Maturity And Organic Matter Type By Principal Components Analysis Of The Distributions Of Polycyclic Aromatic Compounds, Michael A. Kruge Jan 2000

Determination Of Thermal Maturity And Organic Matter Type By Principal Components Analysis Of The Distributions Of Polycyclic Aromatic Compounds, Michael A. Kruge

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The thermal maturity and organofacies sensitivity of polycyclic aromatic compound (PAC) distributions was explored by examination of the aromatic fractions of solvent extracts from a diverse set of 53 shales, coals and kerogen macerals which have undergone either natural or artificial maturation and which represent all three principal sedimentary organic matter (OM) types. Systematic changes with maturation were observed in the following groups of isomers: tri- and tetramethylnaphthalenes, methyl- and dimethylphenanthrenes, methyl- and dimethyldibenzothiophenes, methylpyrenes, and methylchrysenes. The maturity differences were quantified by mathematical ratios of the relative concentrations of the more thermally stable isomers to the less stable, on …

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Chemical Oxidation Of Mtbe Under O2-Rich And O2-Limited Environments Coupled With Biological Degradation Of Oxidation Byproducts, J. Sutherland, B. Panka, Craig D. Adams, Joel Gerard Burken Jan 2000

Chemical Oxidation Of Mtbe Under O2-Rich And O2-Limited Environments Coupled With Biological Degradation Of Oxidation Byproducts, J. Sutherland, B. Panka, Craig D. Adams, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The H2O2/UV Advanced Oxidation Process (AOP) Was Investigated to Determine Byproduct Formation under Different Experimental Conditions (PH, Alkalinity, and H2O2/UV Dose). a Key Factor in the Efficiency of the AOP Was the Dissolved Oxygen Concentration. Gas Chromatography/mass Spectrometry (GC/MS) Analysis Was Used to Identify Byproducts Resulting from Oxidation under Oxygen-Rich and Oxygen-Limited Conditions. Resultant Oxidation Byproducts Were Analyzed for their Susceptibility to Biological Degradation. Biodegradation Rate Constants Were Determined and Modeled for the Primary Byproducts of the Advanced Oxidation Process. Inhibition Resulting from the Presence of Multiple Byproducts in a Biological System Was Investigated as Well. Effects of Process Parameters …

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The Effects Of Light And Nitrate Levels On The Relationship Between Nitrate Reductase Activity And (No3-)-N-15 Uptake: Field Observations In The East China Sea, Chin-Chang Hung, George T. F. Wong, Kom-Kee Liu, Fuh-Kwo Shiah, Gwo-Ching Gong Jan 2000

The Effects Of Light And Nitrate Levels On The Relationship Between Nitrate Reductase Activity And (No3-)-N-15 Uptake: Field Observations In The East China Sea, Chin-Chang Hung, George T. F. Wong, Kom-Kee Liu, Fuh-Kwo Shiah, Gwo-Ching Gong

OES Faculty Publications

Nitrate reductase activity (NRA) and 15NO3- uptake (NU) were determined in the East China Sea and the adjoining Kuroshio in May 1996, at six stations covering a range of hydrographic conditions: the nutrient-rich and fresher plume of Changjiang Diluted Water along the Chinese coast, the nutrient-rich upwelling Kuroshio Subsurface Water at the shelf edge northeast of Taiwan, the oligotrophic Kuroshio Surface Water and the mixing zones among these water masses on the shelf. The values of NRA in the surface mixed layer ranged between 16 and 0.1 nM-N h-1, whereas those of NU ranged between …

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Intraspecific Variation In The Selenium Requirement Of Different Geographic Strains Of The Toxic Dinoflagellate Gymnodinium Catenatum, Martina A. Doblin, Susan I. Blackburn, Gustaaf M. Hallegraeff Jan 2000

Intraspecific Variation In The Selenium Requirement Of Different Geographic Strains Of The Toxic Dinoflagellate Gymnodinium Catenatum, Martina A. Doblin, Susan I. Blackburn, Gustaaf M. Hallegraeff

OES Faculty Publications

The requirement for selenium (IV) was assessed in five strains of the toxic dinoflagellate Gymnodinium catenatum Graham, representing three populations from Tasmania (Australia), as well as one each from Japan and Spain. Strains were grown in nutrient-enriched sea water medium with 10-9 M selenium added as selenite (H2SeO3), or with no added selenium, and monitored for growth and cell yield. Strains exhibited different selenium (Se) requirements, as evidenced by (i) a decrease in exponential growth rate (10-20%) and cell yield (up to 80%) (Japanese strain); (ii) a decrease in cell yield only (Tasmania Derwent Estuary …

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3-Hydroxykynurenine And 3-Hydroxyanthranilic Acid Generate Hydrogen Peroxide And Promote Α-Crystallin Cross Linking By Metal Ion Reduction, Lee E. Goldstein, Michael C. Leopold, Xudong Huang, Craig S. Atwood, Aleister J. Saunders, Mariana Hartshorn, James T. Lim, Et Al. Jan 2000

3-Hydroxykynurenine And 3-Hydroxyanthranilic Acid Generate Hydrogen Peroxide And Promote Α-Crystallin Cross Linking By Metal Ion Reduction, Lee E. Goldstein, Michael C. Leopold, Xudong Huang, Craig S. Atwood, Aleister J. Saunders, Mariana Hartshorn, James T. Lim, Et Al.

Chemistry Faculty Publications

The kynurenine pathway catabolite 3-hydroxykynurenine (3HK) and redox-active metals such as copper and iron are implicated in cataractogenesis. Here we investigate the reaction of kynurenine pathway catabolites with copper and iron, as well as interactions with the major lenticular structural proteins, the R-crystallins. The o-aminophenol kynurenine catabolites 3HK and 3-hydroxyanthranilic acid (3HAA) reduced Cu(II)>Fe(III) to Cu(I) and Fe(II), respectively, whereas quinolinic acid and the nonphenolic kynurenine catabolites kynurenine and anthranilic acid did not reduce either metal. Both 3HK and 3HAA generated superoxide and hydrogen peroxide in a copper-dependent manner. In addition, 3HK and 3HAA fostered copper-dependent R-crystallin cross-linking. 3HK- …

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Mass-Radius Relations For Helium White Dwarfs, Ri̇kkat Ci̇velek, Ni̇lgün Kiziloğlu Jan 2000

Mass-Radius Relations For Helium White Dwarfs, Ri̇kkat Ci̇velek, Ni̇lgün Kiziloğlu

Turkish Journal of Physics

We studied the static mass-radius relation of white dwarf stars with masses greater than 0.45 $M_\odot$. We assumed pure degenerate helium interiors at a finite temperature with luminosity-mass ratio due to neutrino energy loss. We compared the obtained M-R relation with those of other writers.

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An Extended Adiabatic Approach For Nuclear Reactions, Mustafa Yilmaz, Bülent Gönül Jan 2000

An Extended Adiabatic Approach For Nuclear Reactions, Mustafa Yilmaz, Bülent Gönül

Turkish Journal of Physics

In this letter, an alternative approximation is developed for the treatment of breakup process in nuclear reactions, which presents a way of evaluating non-adiabatic corrections to the adiabatic model three-body wavefunction by introducing a more consistent prescription for the continuum n-p center of mass energy. Although the present formalism goes beyond the quasi-adiabatic approach, due to the use of exact continuum channel energies, its application to deuteron involving reactions at medium energies shows that such an approach can not be used in its present form. A possible reason behind this failure is discussed.

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Temperature Dependence Of Vickers Microhardness And Creep Study Of In_X Bi_{2-X} Te_3 Crystals, G. R. Pandya, S. R. Bhavsar, C. F. Desai Jan 2000

Temperature Dependence Of Vickers Microhardness And Creep Study Of In_X Bi_{2-X} Te_3 Crystals, G. R. Pandya, S. R. Bhavsar, C. F. Desai

Turkish Journal of Physics

Temperature dependence of Vickers microhardness of ln$_x$ Bi$_{2-x}$ Te$_3$ single crystals with x ranging from 0.1 to 0.5 has been studied. Loading time dependence of microhardness at different temperatures has been used for creep study in the temperature range 300 K to 400 K. The activation energy for indentation creep of the crystals has been evaluated.

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Microhardness Creep In Single Crystals Of Tin-Chalcogenides, S. M. Vyas, C. F. Desai, R. C. Shah, G. R. Pandya Jan 2000

Microhardness Creep In Single Crystals Of Tin-Chalcogenides, S. M. Vyas, C. F. Desai, R. C. Shah, G. R. Pandya

Turkish Journal of Physics

SnSe and SnS have been grown by Bridgman- Stockbarger method. Loading time as a function of vickers microhardness has been measured at different temperatures in the range 303 K to 388K. Al measurement of hardness have been carried out on the cleavage planes. The activation energy for creep has been evaluated to be 2.92 and 1.75 K Cal/mole, respectively, for SnSe and SnS crystals.

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