Phase-Transformation Synthesis of SAPO-34 and a Novel SAPO Molecular Sieve with RHO Framework Type from a SAPO-5 Precursor

2011 ◽  
Vol 23 (6) ◽  
pp. 1406-1413 ◽  
Author(s):  
Peng Tian ◽  
Xiong Su ◽  
Yingxia Wang ◽  
Qinghua Xia ◽  
Ying Zhang ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Molecular Sieve

Hexagonal-orthorhombic phase transformation of AlPO4-5 aluminophosphate molecular sieve

1993 ◽  
Vol 2 (1) ◽  
pp. 73-74 ◽  
Author(s):  
Naoyuki Ohnishi ◽  
Shilun Qiu ◽  
Osamu Terasaki ◽  
Tsuyoshi Kajitani ◽  
Kenji Hiraga
Keyword(s):  
Phase Transformation ◽  
Molecular Sieve ◽  
Orthorhombic Phase

scholarly journals Synthesis of SAPO-20 Using Isopropylamine as a Template from a SAPO-34 Precursor

2021 ◽  
Author(s):  
Hairong Zhang ◽  
Hongyan Liu ◽  
Ruijie Bai ◽  
Rong Sun ◽  
Xi Zhang ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Energy Saving ◽  
Molecular Sieve ◽  
Treatment Time ◽  
Post Treatment ◽  
Comprehensive Utilization ◽  
Hexagonal Shape ◽  
Consumption Reduction

SAPO-20 molecular sieve with the SOD framework was successfully synthesized using SAPO-34 as the precursor and isopropylamine (IPA) as the template by phase-transformation route. The influence of post-treatment time (in IPA, H2O, and SAPO-34 system) and NaOH concentration (in IPA, NaOH, H2O, and SAPO-34 system) on the products was investigated. The results showed that sheet debris SAPO-34 building the hollow-inside cubic morphologies which was padding with irregular SAPO-34. It was received for the as-synthesized spherical aggregation SAPO-20 with hexagonal shape when the ratio of n(OH-)/n (H2O) is 0.12 and the ratio of n(IPA)/n (H2O) is 0.07 in the synthesis gel. This method not only develops a new route for the synthesis of SAPO-20 molecular sieve, but also provides a way of using waste SAPO-34 catalyst, which can be used as a new exploration model for energy saving, consumption reduction and comprehensive utilization in SAPO-34 catalyst process.

Phase Transformation In Ti-6al-4v Alloys

1972 ◽  
Vol 30 ◽  
pp. 584-585
Author(s):  
Shiro Fujishiro
Keyword(s):  
Phase Transformation ◽  
Grain Boundary ◽  
Cryogenic Temperature ◽  
Β Phase ◽  
Heat Treated ◽  
Mixed Microstructure ◽  
Ductile Behavior

The Ti-6 wt.% Al-4 wt.% V commercial alloys have exhibited an improved formability at cryogenic temperature when the alloys were heat-treated prior to the tests. The author was interested in further investigating this unusual ductile behavior which may be associated with the strain-induced transformation or twinning of the a phase, enhanced at lower temperatures. The starting materials, supplied by RMI Co., Niles, Ohio were rolled mill products in the form of 40 mil sheets. The microstructure of the as-received materials contained mainly ellipsoidal α grains measuring between 1 and 5μ. The β phase formed an undefined grain boundary around the a grains. The specimens were homogenized at 1050°C for one hour, followed by aging at 500°C for two hours, and then quenched in water to produce the α/β mixed microstructure.

Microstructural and Microchemical Characterization of Nickel Sulfide Inclusions in Plate Glass

1991 ◽  
Vol 49 ◽  
pp. 962-963
Author(s):  
J. Cooper ◽  
O. Popoola ◽  
W. M. Kriven
Keyword(s):  
Thermal Expansion ◽  
Phase Transformation ◽  
Glass Matrix ◽  
Nickel Sulfide ◽  
Plate Glass ◽  
Thermal Expansion Mismatch ◽  
Volume Increase ◽  
Β Phase ◽  
Microchemical Characterization

Nickel sulfide inclusions have been implicated in the spontaneous fracture of large windows of tempered plate glass. Two alternative explanations for the fracture-initiating behaviour of these inclusions have been proposed: (1) the volume increase which accompanies the α to β phase transformation in stoichiometric NiS, and (2) the thermal expansion mismatch between the nickel sulfide phases and the glass matrix. The microstructure and microchemistry of the small inclusions (80 to 250 μm spheres), needed to determine the cause of fracture, have not been well characterized hitherto. The aim of this communication is to report a detailed TEM and EDS study of the inclusions.

Polymorphic phase transition of a membrane protein - analysis of continuous diffuse electron diffraction intensity

1986 ◽  
Vol 44 ◽  
pp. 166-167
Author(s):  
Douglas L. Dorset ◽  
Andrew K. Massalski
Keyword(s):  
Molecular Sieve ◽  
Three Dimensional ◽  
Pore Geometry ◽  
Two Dimensional ◽  
Diffraction Intensity ◽  
Polymorphic Phase Transition ◽  
E Coli ◽  
Crystallographic Study ◽  
Hexagonal Form ◽  
Polymorphic Forms

Matrix porin, the ompF gene product of E. coli, has been the object of a electron crystallographic study of its pore geometry in an attempt to understand its function as a membrane molecular sieve. Three polymorphic forms have been found for two-dimensional crystals reconstituted in phospholipid, two hexagonal forms with different lipid content and an orthorhombic form coexisting with and similar to the hexagonal form found after lipid loss. In projection these have been shown to retain the same three-fold pore triplet geometry and analyses of three-dimensional data reveal that the small hexagonal and orthorhombic polymorphs have similar structure as well as unit cell spacings.

AEM of reaction-bonded SiC

1992 ◽  
Vol 50 (1) ◽  
pp. 344-345
Author(s):  
K Das Chowdhury ◽  
R. W. Carpenter ◽  
W. Braue
Keyword(s):  
Mechanical Properties ◽  
Phase Transformation ◽  
High Temperature ◽  
Epitaxial Growth ◽  
Liquid Silicon ◽  
Structural Ceramic ◽  
Few Data

Research on reaction-bonded SiC (RBSiC) is aimed at developing a reliable structural ceramic with improved mechanical properties. The starting materials for RBSiC were Si,C and α-SiC powder. The formation of the complex microstructure of RBSiC involves (i) solution of carbon in liquid silicon, (ii) nucleation and epitaxial growth of secondary β-SiC on the original α-SiC grains followed by (iii) β>α-SiC phase transformation of newly formed SiC. Due to their coherent nature, epitaxial SiC/SiC interfaces are considered to be segregation-free and “strong” with respect to their effect on the mechanical properties of RBSiC. But the “weak” Si/SiC interface limits its use in high temperature situations. However, few data exist on the structure and chemistry of these interfaces. Microanalytical results obtained by parallel EELS and HREM imaging are reported here.

Fibrillin molecules aggregate to form an extendible beaded structure which is a major component of “Elastin Associated” microfibrils

1989 ◽  
Vol 47 ◽  
pp. 246-247
Author(s):  
Douglas R. Keene ◽  
B. Kerry Maddox ◽  
Marie B. Spurgin ◽  
Lynn Y. Sakai ◽  
Robert W. Glanville
Keyword(s):  
Molecular Sieve ◽  
Room Temperature ◽  
Culture Medium ◽  
Weight Fraction ◽  
Ammonium Bicarbonate ◽  
High Molecular Weight Fraction ◽  
Bicarbonate Buffer ◽  
Human Amnion ◽  
Gold Conjugate ◽  
Ammonium Bicarbonate Buffer

A mouse monoclonal antibody was used to identify beaded aggregates found in guanidine extracts of human amnion as assemblies of fibrillin molecules. These aggregates were also shown to be a major component of extracellular matrix microfibrils. We further demonstrated that the periodicity of these aggregates can be increased when subjected to mechanical stress.Human amnion was extracted with guanidine and the extracted material purified using ion exchange and molecular sieve chromatography. A high molecular weight fraction was precipitated by dialyzing against dilute acetic acid. Part of the precipitate was suspended in 0.2 M ammonium bicarbonate buffer and rotary shadowed. A second portion was resuspended in culture medium containing antibody which recognizes matrix microfibrils, diluted 1:5 in ammonium bicarbonate and reacted for 120 minutes at room temperature. Antibody labeled precipitate was washed by repeated pelleting and resuspension in buffer and then incubated in Janssen GAM 5 nm gold conjugate for 60 minutes at room temperature.

Phase transformation and layer evolution in molybdenum disilicide-silicon carbide nanolayered coatings

1994 ◽  
Vol 52 ◽  
pp. 538-539
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J.-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Matrix Material ◽  
Molybdenum Disilicide ◽  
High Temperature Strength ◽  
Cross Sectional ◽  
Good Oxidation Resistance ◽  
Structural Applications

MoSi2 is a potential matrix material for high temperature structural composites due to its high melting temperature and good oxidation resistance at elevated temperatures. The two major drawbacksfor structural applications are inadequate high temperature strength and poor low temperature ductility. The search for appropriate composite additions has been the focus of extensive investigations in recent years. The addition of SiC in a nanolayered configuration was shown to exhibit superior oxidation resistance and significant hardness increase through annealing at 500°C. One potential application of MoSi2- SiC multilayers is for high temperature coatings, where structural stability ofthe layering is of major concern. In this study, we have systematically investigated both the evolution of phases and the stability of layers by varying the heat treating conditions.Alternating layers of MoSi2 and SiC were synthesized by DC-magnetron and rf-diode sputtering respectively. Cross-sectional transmission electron microscopy (XTEM) was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures.

Ferroelectric Domain Structure of Pb(Zr.52Ti.48)03

1980 ◽  
Vol 38 ◽  
pp. 214-215
Author(s):  
E.K. Goo ◽  
R.K. Mishra
Keyword(s):  
Phase Transformation ◽  
Domain Structure ◽  
Tetragonal Phase ◽  
Ferroelectric Domain ◽  
Cubic Phase ◽  
Ion Milling ◽  
Thin Foils ◽  
Ferroelectric Domain Structure ◽  
Ferroelectric Domains

Ferroelectric domains are twins that are formed when PZT undergoes a phase transformation from a non-ferroelectric cubic phase to a ferroelectric tetragonal phase upon cooling below ∼375°C.,1 The tetragonal phase is spontaneously polarized in the direction of c-axis, making each twin a ferroelectric domain. Thin foils of polycrystalline Pb (Zr.52Ti.48)03 were made by ion milling and observed in the Philips EM301 with a double tilt stage.

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