A NEW SUPERCONDUCTING MATERIAL IN A Y-Ba-Cu-O AND Bi-Ca-Sr-Cu-O MIXED SYSTEM

1989 ◽  
Vol 03 (05) ◽  
pp. 447-451
Author(s):  
M.A.K.L. DISSANAYAKE ◽  
K. TENNEKONE ◽  
O.A. ILEPERUMA ◽  
S.H.S.P. SAMARAPPULI
Keyword(s):  
Diffraction Pattern ◽  
Superconducting Phase ◽  
The Other ◽  
Mixed System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Superconducting Material ◽  
Other Hand ◽  
Stoichiometric Ratios

A new superconducting phase has been found in a mixed system prepared from the YBa 2 Cu 3 O 7−δ and Bi 2 CaSr 2 Cu 2 O 9−δ high-T c materials. The new compound shows an onset of resistivity transition at ~100 K and zero resistivity below ~50 K. Powder X-ray diffraction pattern of the new compound differs completely from those of YBa 2 Cu 3 O 7−δ and Bi 2 CaSr 2 Cu 2 O 9−δ. The materials prepared using a mixture of the oxides and carbonates with identical cation stoichiometric ratios, on the other hand, does not exhibit superconductivity.

X-Ray Diffraction of Iron Containing Samples: The Importance of a Suitable Configuration

2017 ◽  
Vol 262 ◽  
pp. 545-548 ◽  
Author(s):  
Yvonne M. Mos ◽  
Arnold C. Vermeulen ◽  
Cees N.J. Buisman ◽  
Jan Weijma
Keyword(s):  
Radiation Source ◽  
The Other ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
High Quality ◽  
Crystalline Phases ◽  
X Ray ◽  
Other Hand ◽  
Cobalt Radiation

X-ray diffraction (XRD) is a commonly used technology to identify crystalline phases. However, care must be taken with the combination of XRD configuration and sample. Copper (most commonly used radiation source) is a poor match with iron containing materials due to induced fluorescence. Magnetite and maghemite are analysed in different configurations using copper or cobalt radiation. Results show the effects of fluorescence repressing measures and the superiority of diffractograms obtained with cobalt radiation. Diffractograms obtained with copper radiation make incontestable phase identification often impossible. Cobalt radiation on the other hand yields high quality diffractograms, making phase identification straightforward.

Crystal chemistry of the compound Sr2Bi2CuO6

1990 ◽  
Vol 5 (1) ◽  
pp. 46-52 ◽  
Author(s):  
R. S. Roth ◽  
C. J. Rawn ◽  
L. A. Bendersky
Keyword(s):  
Electron Diffraction ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Crystal Chemistry ◽  
Superconducting Phase ◽  
X Ray Diffraction ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Symmetry Space ◽  
Symmetry Space Group

The compound Sr2Bi2CuO6 should nominally be the phase with n = 1 of the high Tc superconducting series Sr2Bi2CanO4+2n. However, the superconducting phase with n = 1 (with no CaO) occurs only with a gross deficiency in SrO content. Instead, at the composition Sr2Bi2CuO6, a different phase is formed with an x-ray diffraction pattern considerably different from that expected for the n −1 member of the series. This phase has been found, by a combination of electron diffraction and single crystal and powder x-ray diffraction, to have a commensurate lattice with monoclinic symmetry, space group C2/m or Cm, a = 24.473 (2), b = 5.4223 (5), c = 21.959 (2)A, and β = 105.40 (1)°. The actual composition of this phase may be deficient in CuO by as much as 1.0 mole %.

Powder X-Ray Data for Synthetic Anhydrous Sodium Zirconium Silicates

1987 ◽  
Vol 2 (3) ◽  
pp. 176-179 ◽  
Author(s):  
G. Wilson ◽  
F. P. Glasser
Keyword(s):  
Solid State ◽  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Solid State Reaction ◽  
The Other ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
X Ray ◽  
Sodium Zirconium ◽  
Diffraction Patterns

AbstractA systematic survey of phase formation in the Na2O-ZrO2-SiO2 system has revealed inconsistencies in the number and identity of ternary phases, and of their X-ray powder data. The phases Na2ZrSiO5, Na4Zr2Si3O12, Na2ZrSi2O7 and Na2ZrSi4O11 were prepared by solid-state reaction and their experimental X-ray diffraction patterns measured. Calculated X-ray diffraction patterns were generated by computer, using published crystallographic data, and critically compared with the experimentally observed values. The unit-cell constants were redefined to a greater accuracy than the presently accepted values published in the Powder Diffraction File. Only Na4Zr2Si3O12 produced an X-ray diffraction pattern which agreed with that previously published; those from the other phases were significantly different in both the intensities and positions of the reflections. Data for synthetic Na2ZrSi4O11 identical to the mineral vlasovite are reported.

Metallographic, Structural and Mechanical Characterization of a Low Density Fe-Mn-Al-C Steel Microalloyed with Ti/B in As-Cast and Homogenized Conditions

MRS Advances ◽  
2018 ◽  
Vol 3 (64) ◽  
pp. 3971-3978 ◽  
Author(s):  
O.E. Villanueva-Perez ◽  
I. Mejía ◽  
V. García-García ◽  
A. Bedolla-Jacuinde
Keyword(s):  
Grain Size ◽  
Mechanical Characterization ◽  
The Other ◽  
Low Density ◽  
X Ray Diffraction ◽  
X Ray ◽  
Other Hand ◽  
Average Grain Size ◽  
Cast Condition

ABSTRACTLow density (LD) steels have shown particular characteristics in terms of mechanical properties and microstructure, since they have high strength, high ductility and density reduction up to 18%. On the other hand, the addition of microalloying elements such as Ti and B generate hardening by solid solution and precipitation, as well as grain refinement effect. LD steels generate nano-sized kappa phase precipitated from the austenite matrix, and these advanced steels can reach strength and elongation up to 780 MPa and 60%, respectively. The main objective of this research work is the metallographic, structural and mechanical characterization of a LD steel microalloyed with Ti/B in as-cast and -homogenized conditions. For this purpose a Fe-27Mn-7Al-1.2C (%wt) LD steel microalloyed with Ti/B was melted in a vacuum-induction furnace and cast in metallic mold. LD-Ti/B steel samples were homogenized at 1100 °C during 20, 50, 100, 150 and 200 minutes followed by water quenching. Metallographic, structural and mechanical characterization was carried out by optical (LOM) and scanning electron (SEM) microscopy, X-ray diffraction (XRD) and microhardness Vickers testing (HV10), respectively. In general, results showed a typical dendritic microstructure with average grain size of 1256 μm in the as-cast condition. On the other hand, the as-homogenized condition showed an austenitic equiaxial microstructure with average grain size from 164 to 940 μm. Austenite, ferrite and kappa phases were detected by X-ray diffraction (XRD). Also, second-phase particles such as AlN, TiC and MnS were detected by LOM and SEM-EDS analysis. LD steel microalloyed with Ti/B exhibited the highest microhardness Vickers value (235 HV10) in the as-cast condition, whilst in the as-homogenized condition microhardness gradually decreases from 223 to 198 HV10 as holding time increases.

Alignment of Primary Phase of a Binary Alloy during Solidification

2007 ◽  
Vol 26-28 ◽  
pp. 563-565
Author(s):  
Kazuhiko Iwai ◽  
Manabu Usui ◽  
Shigeo Asai
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Diffraction Pattern ◽  
Primary Phase ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Specific Direction ◽  
Crystal Alignment ◽  
The Magnetic Field

A static magnetic field and an alternating current are imposed on a metallic alloy during solidification for a crystal alignment of the primary phase. A Sn-10%Pb is selected as a sample because its primary phase is expected to have an anisotropic nature in magnetic susceptibility. In the x-ray diffraction pattern of the sample solidified without the magnetic field, the first and second highest peaks are (101) and (211) planes. On the other hand, those solidified with the magnetic field are (200) and (220) planes which are magnetically preferred planes. That is, the primary phase crystals in the sample solidified with the magnetic field are aligned to the specific direction.

Lattice parameters and spontaneous strain in AX 2 polytypes: CdI2, PbI2 SnS2 and SnSe2

1989 ◽  
Vol 22 (6) ◽  
pp. 622-623 ◽  
Author(s):  
B. Pałosz ◽  
E. Salje
Keyword(s):  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Basal Plane ◽  
Lattice Parameter ◽  
Structural Transformations ◽  
Lattice Parameters ◽  
The Other ◽  
X Ray Diffraction ◽  
Spontaneous Strain ◽  
X Ray

Structural transformations between polytypes of a given material are expected to lead to lattice relaxations. Powder X-ray diffraction of basic AX 2 polytypes of CdI2, PbI2, SnS2 and SnSe2 showed these relaxations for the repetition unit along the stacking axis, conventionally the c axis. No variation of the lattice parameters were detected in the basal plane (001), except for CdI2 where small variations occur also for the a lattice parameter. The tensor of the spontaneous strain has its maximum component e 3 ≲ 12 × 10−4 for SnS2. The powder diffraction pattern and lattice parameters of the phases of CdI2 (2H, 12R, 4H), PbI2 (2H, 12R), SnS2 (2H, 18R, 4H) and SnSe2 (2H, 18R) are given. JCPDS Diffraction File Nos. are: 40-1468 for CdI2-12H; 40–1469 for CdI2-2H; 40-1466 for SnS2-18R, 40–1467 for SnS2-2H; 40–1465 for SnSe2-18R. The other polytypes studied in this paper have data in earlier sets of the PDF.

Thermolysis of Some Spirobenzopyran-3’,2-[1,3,4]oxadithiino- [5,6-c]benzopyran-4’-ones in the Presence of Some Homodienes and Crystallographic Studies of Some Adducts

2006 ◽  
Vol 61 (11) ◽  
pp. 1413-1420 ◽  
Author(s):  
Mohamed I. Hegab ◽  
A. M. Moustafa
Keyword(s):  
Single Crystal ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Other Hand ◽  
Good Support

The very reactive α-oxo-thioketone derivatives 2a - d, generated via thermolysis of spirobenzopyran- 3’,2-[1,3,4]oxadithiino[5,6-c]benzopyran-4’-ones 1a - d, reacted with 2,3-dimethyl-1,3-butadiene and 1,3-cyclohexadiene under [4+2]-cycloaddition to afford spirobenzopyran-3’,6-thiapyran-4’-one adducts 3a - d and spirobenzopyran-3’,3-thiabicyclo[2.2.2]oct-5-en-4’-one adducts 4a - d, respectively. On the other hand, the reaction of α-oxo-thioketones 2a - d with isoprene afforded regioselectively only 3-methyl-thiapyran derivatives 5a - d. Single crystal X-ray diffraction studies of 4b, 4c, and 5a give a good support for the established structure.

scholarly journals THE SPECIFIC HEAT AND THE HEAT OF COMPRESSION OF HUMAN RED CELLS, SICKLED RED CELLS, AND PARACRYSTALLINE RAT RED CELLS

1955 ◽  
Vol 38 (5) ◽  
pp. 575-580 ◽  
Author(s):  
Eric Ponder
Keyword(s):  
Thermal Properties ◽  
Specific Heat ◽  
Crystallization Process ◽  
Red Cells ◽  
The Other ◽  
Red Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Other Hand ◽  
Human Red Cells

The investigation of two thermal properties of red cells throws some light on whether sickling is a process involving the crystallization of a relatively insoluble hemoglobin. These properties are the specific heat and the heat of compression, both of which would be expected to become numerically less if the hemoglobin of the red cell were to crystallize. In the case of paracrystalline rat red cells, which give spacings at 45 A and 58 A by x-ray diffraction, the specific heat is reduced to 85 per cent of that of the normal red cells, and the heat of compression is only about 75 per cent of that found for the normal red cell. In the case of the red cell sickled by a reduction of the O2 tension, the specific heat and the heat of compression are substantially the same as found for the normal red cell. This is an argument against sickling being the result of a crystallization process, and supports the observation that sickled cells do not give x-ray spacings. The result is compatible, on the other hand, with sickling being the result of the formation of an oriented and birefringent gel.

Complexes of Tris(N-piperidinomethyl)phosphine Oxide with Zinc and Cadmium

1996 ◽  
Vol 61 (9) ◽  
pp. 1321-1334 ◽  
Author(s):  
Pavel Vojtíšek ◽  
Ivana Císařová
Keyword(s):  
Coordination Sphere ◽  
Phosphine Oxide ◽  
Chelate Ring ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Membered Chelate Ring ◽  
Other Hand ◽  
Ring Structures ◽  
The Way

A number of compounds which can by their stoichiometry be classified into several groups have been prepared by reaction of tris(N-piperidinomethyl)phosphine oxide (tppo) with Zn(II) and Cd(II) salts. The structure of two Zn(II) complexes differing by their Zn : tppo ratio and of one Cd(II) complex has been determined by the X-ray diffraction technique. The results show that in all the cases tppo is bound as divalent chelate N,O-donor, but the geometry of coordination sphere of M(II) decisively affects the steric arrangement of the five-membered chelate ring. Structures of the compounds studied are entirely different from those of Zn(II) complexes of sterically less demanding P,P-dimethyl-P-aminomethylphosphine oxide (dmao). On the other hand, the way of coordination of tppo is the same as that found in the case of the Co(II) complex of tris(N,N-dimethylaminomethyl)phosphine oxide.

scholarly journals Perbandingan porselen kedokteran gigi swa-sintesis berbahan baku pasir felspar Pangaribuan dan Sukabumi

2017 ◽  
Vol 3 (3) ◽  
pp. 49
Author(s):  
Joseph Gunawan ◽  
Dede Taufik ◽  
Veni Takarini ◽  
Zulia Hasratiningsih
Keyword(s):  
Potassium Salt ◽  
Raw Materials ◽  
The Other ◽  
Good Prospect ◽  
X Ray Diffraction ◽  
Natural Sand ◽  
Dental Porcelain ◽  
X Ray ◽  
Other Hand

Comparison self-synthesized dental porcelain between feldspar from Pangaribuan and Sukabumi. Dental porcelain material as one of the esthetic indirect restorations in Indonesia is mostly imported. In fact, Indonesia is really rich of natural raw materials, including feldspar, silica, and kaolinite. The aim of this study is to synthesize the dental porcelain made from Indonesia’s two different originates, which are Pangaribuan and Sukabumi. This study was prepared by fritting and sintering the mixture of 65% wt feldspar (from Sukabumi and Pangaribuan), 25% wt silica, 5% wt kaolinite, and 5% wt potassium salt. The porcelains obtained were evaluated using X-Ray Diffraction (XRD). The results revealed that quartz and leucite were found in the composition of Pangaribuan sand that successfully showed more translucencies compared to Sukabumi sand which only imparted quartz on its component. This study shows that dental porcelain from Pangaribuan sand is successfully self-synthesized, on the other hand Sukabumi sand has not been successfully synthesized. These findings develop on a good prospect of esthetic dental porcelain made from Indonesian natural sand. ABSTRAKBahan porselen kedokteran gigi sebagai salah satu restorasi indirek estetik di Indonesia kebanyakan didatangkan dari luar negeri. Indonesia sebenarnya sangat kaya dengan bahan baku porselen kedokteran gigi seperti felspar, silika, dan kaolin. Tujuan penelitian ini adalah melakukan sintesis porselen kedokteran gigi dari 2 jenis pasir alam Indonesia yaitu Pangaribuan dan Sukabumi. Komposisi yang digunakan yaitu 65% wt felspar, 25% wt silika, 5% wt kaolin, dan 5% wt garam kalium, dicampur kemudian dilakukan fritting serta sintering. Dua komposisi porselen dibuat dengan bahan dasar berbeda yaitu felspar dari Pangaribuan dan Sukabumi. Kedua porselen yang telah disintering kemudian dievaluasi menggunakan X-Ray Diffraction (XRD). Hasilnya adalah kuarsa dan leusit ditemukan pada porselen dengan komposisi pasir Pangaribuan yang juga memberikan hasil lebih translusen secara visual dibandingkan dengan porselen dengan komposisi pasir Sukabumi yang hanya memperlihatkan hasil kuarsa. Hal ini menunjukkan bahwa porselen dengan komposisi bahan dasar pasir Pangaribuan berhasil disintesis dibandingkan komposisi bahan dasar pasir Sukabumi.Penemuan ini dapat memberikan peluang yang baik dalam pembuatan porselen kedokteran gigi yang berasal dari pasir alam Indonesia. 

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