scholarly journals Estimation of CE-CVM energy parameters from miscibility gap data

2005 ◽  
Vol 28 (2) ◽  
pp. 173-177 ◽  
Author(s):  
G. Srinivasa Gupta ◽  
G. Vamsi Madhav ◽  
A. Pandey ◽  
B. Nageswara Sarma ◽  
S. Lele
1989 ◽  
Vol 145 ◽  
Author(s):  
Allan E. Schultz ◽  
Y. Austin Chang

AbstractExtensive new data and modeling in the In-Ga-As system has allowed the authors to reexamine the phase equilibria between the melt and the epitaxial solid. A detailed thermodynamic model was constructed with the following improvements: (1) The solid-solid interaction parameters were based on InAs-GaAs miscibility gap data, and (2) liquid-bulk solid, as well as liquid-epitaxial solid, tie-lines were used. Comparison of tie- lines from epitaxial systems and bulk systems demonstrated that strain energy is not the dominant factor in equilibrium growth of epitaxial solid films of In1-xGaxAs on any Ill-V binary substrate. Both the “lattice- pulling” effect and the “substrate-orientation” effect were shown to be caused by different quaternary equilibria at the In1-xGaxAs/InP interface, and not by film-substrate strain.


Author(s):  
M.G. Burke ◽  
M.K. Miller

Interpretation of fine-scale microstructures containing high volume fractions of second phase is complex. In particular, microstructures developed through decomposition within low temperature miscibility gaps may be extremely fine. This paper compares the morphological interpretations of such complex microstructures by the high-resolution techniques of TEM and atom probe field-ion microscopy (APFIM).The Fe-25 at% Be alloy selected for this study was aged within the low temperature miscibility gap to form a <100> aligned two-phase microstructure. This triaxially modulated microstructure is composed of an Fe-rich ferrite phase and a B2-ordered Be-enriched phase. The microstructural characterization through conventional bright-field TEM is inadequate because of the many contributions to image contrast. The ordering reaction which accompanies spinodal decomposition in this alloy permits simplification of the image by the use of the centered dark field technique to image just one phase. A CDF image formed with a B2 superlattice reflection is shown in fig. 1. In this CDF micrograph, the the B2-ordered Be-enriched phase appears as bright regions in the darkly-imaging ferrite. By examining the specimen in a [001] orientation, the <100> nature of the modulations is evident.


Author(s):  
R.W. Carpenter ◽  
Changhai Li ◽  
David J. Smith

Binary Nb-Hf alloys exhibit a wide bcc solid solution phase field at temperatures above the Hfα→ß transition (2023K) and a two phase bcc+hcp field at lower temperatures. The β solvus exhibits a small slope above about 1500K, suggesting the possible existence of a miscibility gap. An earlier investigation showed that two morphological forms of precipitate occur during the bcc→hcp transformation. The equilibrium morphology is rod-type with axes along <113> bcc. The crystallographic habit of the rod precipitate follows the Burgers relations: {110}||{0001}, <112> || <1010>. The earlier metastable form, transition α, occurs as thin discs with {100} habit. The {100} discs induce large strains in the matrix. Selected area diffraction examination of regions ∼2 microns in diameter containing many disc precipitates showed that, a diffuse intensity distribution whose symmetry resembled the distribution of equilibrium α Bragg spots was associated with the disc precipitate.


2019 ◽  
Vol 3 ◽  
pp. 871
Author(s):  
Desita Anggraeni ◽  
M. Nurkholis Fauzi ◽  
Christian Novia Ngesti H.

Padang lamun merupakan habitat penting pesisir yang memiliki peran kunci dalam ekosistem pesisir. Kawasan ini merupakan area asuhan bagi ikan-ikan kecil, udang, persembunyian biota dari predatornya, pendaur zat hara, serta penyerap nutrien dari limpasan air laut yang dapat membantu menstabilkan sedimen dan kejernihan air. Kepulauan Tanimbar merupakan salah satu lokasi di Provinsi Maluku dengan potensi sebaran lamun yang cukup luas, namun informasi mengenai sebaran lamun di kawasan ini tidak terdata dengan baik. Teknologi penginderaan jauh merupakan salah satu alternatif untuk mengisi gap data di area yang luas dan sulit dijangkau, termasuk untuk memetakan sebaran lamun di Kepulauan Tanimbar. Penelitian ini bertujuan untuk menyediakan data dasar sebaran dan luas habitat lamun di pesisir Kepulauan Tanimbar. Metode yang digunakan adalah analisis citra penginderaan jauh Landsat 8, menerapkan penajaman citra untuk perairan dangkal menggunakan algoritma Lyzenga. Citra Landsat yang digunakan Landsat Surface Reflectance liputan path/row 106/65 dan 106/66 tahun perekaman 2017. Pengambilan data lapangan dilakukan pada tanggal 1-10 November 2017. Metode pengambilan data lamun dilakukan menggunakan metode seagrass watch . Hasil pengolahan citra menunjukkan lamun terdistribusi merata di seluruh pesisir Kepulauan Tanimbar dengan luas total 5.615,63 hektar dengan tutupan terpadat di sekitar Pulau Seira. Hasil survei lapangan menunjukkan tutupan lamun terpadat dijumpai di Formusan dengan tutupan lamun rata-rata 95%. Kondisi lamun paling baik berada di daerah Sabal, didukung kondisi air yang sangat jernih dengan substrat utama pasir. Berdasarkan hasil pengamatan lapangan, jenis lamun yang ditemukan antara lain: E n h alu s a c o r oid e s , T h ala s sia h e m p ric hii, C y m o d o c e a s e r r ula t a , C y m o d o c e a rotundata, Syringodi um isoetifolium, Halodule uninervis, Halophila ovalis, dan Halophila minor .


2020 ◽  
Vol 56 (6) ◽  
pp. 655-669
Author(s):  
A. A. Vasil’ev ◽  
V. A. Vasil’ev

1986 ◽  
Vol 51 (4) ◽  
pp. 731-737
Author(s):  
Viliam Klimo ◽  
Jozef Tiňo

Geometry and energy parameters of the individual dissociation intermediate steps of CH4 molecule, parameters of the barrier to linearity and singlet-triplet separation of the CH2 molecule have been calculated by means of the UMP method in the minimum basis set augmented with the bond functions. The results agree well with experimental data except for the geometry of CH2(1A1) and relatively high energy values of CH(2II) and CH2(1A1) where the existence of two UHF solutions indicates a necessity of description of the electronic correlation by more exact methods of quantum chemistry.


2018 ◽  
Vol 481 (1) ◽  
pp. 877-878
Author(s):  
F. A. Letnikov ◽  
B. S. Danilov ◽  
A. F. Letnikova

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