scholarly journals Analyzing Frequency Spectra of Dielectric Loss to Clarify Influence of L,α-alanine Doping on Phase Transition in Triglycine Sulfate

2021 ◽  
Author(s):  
Bich Dung MAI
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Dielectric Loss ◽  
Phase Transition Temperature ◽  
Physical Method ◽  
Ferroelectric Material ◽  
Triglycine Sulfate ◽  
Frequency Spectra ◽  
The Relationship ◽  
La Doped

As reported in the literature, the doping of L,α-alanine (LA) led to increasing the phase transition temperature in triglycine sulfate (TGS) – a bio-ferroelectric material that has been widely applied in industry. The nature of this anomaly is commonly investigated by considerably complicated theoretical and experimental techniques. Unlike previous studies, the present work proposes a simple physical method of analyzing frequency spectra for dielectric loss to clarify the relationship between the movement of phase transition positions and the shift of relaxation frequencies observed in the spectra. The experimental results obtained for LA-doped TGS samples synthesized at different LA contents (0, 5, 10, 20, and 30 wt.%) were used for the analysis. It was indicated that the increase in phase transition temperature was accompanied by the decrease in relaxation frequencies due to the enhanced viscosity created by strong hydrogen bonds formed between amino acids of alanine and TGS structure.

DIELECTRIC PHENOMENA AT PHASE TRANSITION TEMPERATURE OF NANOCOMPOSITES BASED ON FERROELECTRICS AND NANOCRYSTALLINE CELLULOSE ACETOBACTER XYLINUM

2020 ◽  
Vol 27 (03) ◽  
Author(s):  
NGUYEN HOAI THUONG ◽  
MAI BICH DUNG ◽  
NGUYEN THI LAN HUONG ◽  
DOAN VAN DAT
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Sodium Nitrite ◽  
Dipole Interaction ◽  
Acetobacter Xylinum ◽  
Nanocrystalline Cellulose ◽  
Triglycine Sulfate ◽  
Hydrogen Bond System ◽  
The Matrix

Dielectric phenomena at phase transition temperature for nanoparticles of triglycine sulfate (TGS) and Sodium Nitrite (NaNO2) embedded into the pores of bacterial nanocrystalline cellulose Acetobacter Xylinum have been investigated. It was shown that the phase transition temperature of these ferroelectrics at nanoscale level strongly changes as compared to those of the massif ferroelectrics: for hydrogen-containing triglycine sulfate nanoparticles the phase transition temperature was shifted to higher temperatures and for non-hydrogen-containing Sodium Nitrite nanoparticles – lower temperatures. The obtained results are explained by knowledge of size effects and the interaction between the matrix and ferroelectric inclusions through hydrogen-bond system as well as dipole-dipole interaction between TGS nanoparticles using a mathematical expansion based on Landau-Ginzburg-Devonshire theory.

Change of Phase Transition Temperature in Band Engineered Ferroelectric Lanthanum-Modified Bismuth Titanates

2020 ◽  
Vol 20 (11) ◽  
pp. 7135-7139
Author(s):  
Rui Tang ◽  
Sangmo Kim ◽  
Chung Wung Bark
Keyword(s):  
Phase Transition ◽  
Dielectric Constant ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Ferroelectric Properties ◽  
Solar Spectrum ◽  
Ferroelectric Material ◽  
Transition Temperatures ◽  
Phase Transition Temperatures ◽  
Increasing Temperature

The ferroelectric material chosen for a solar cell has to absorb as much of the solar spectrum as possible, therefore a low band gap is desirable, but it is rarely known for phase transition temperature on the bandgap engineered ferroelectric materials. The phase transition temperature of a ferroelectric material can be determined by monitoring its dielectric constant with increasing temperature, as the dielectric constant changes abruptly at the phase transition temperature. Here, we inform the measurement of the phase transition temperature of the ferroelectric complex oxide Bi3.25La0.75Ti3O12 as well as cobalt and iron doped Bi3.25La0.75Ti3O12 bulk ceramics for photovoltaic cells based on dielectric monitoring with changing temperature. We synthesized lanthanum-modified bismuth-titanate-based ceramics with various doping concentrations transition metal to Ti. X-ray diffraction analysis revealed that all the compounds crystallized in an orthorhombic structure. Their morphologies and size distributions were observed using scanning electron microscopy. From the ultraviolet-visible spectroscopy absorption spectra of the synthesized powder, bandgaps were checked. An inductance-capacitance-resistance meter was used to obtain the relationship between dielectric responses and the temperature of the targets in a tube furnace. We observed that the dielectric constant increases gradually with increasing temperature, until the transition temperature and subsequently decreases, and we were able to determine the phase transition temperatures of the tested materials. Furthermore, the results revealed that all the doped bismuth titanates keep their phase transition temperatures, which were sufficiently high, to maintain their ferroelectric properties above room temperature.

Phase Transition Temperatures of Divalent and Trivalent Ions Substituted (Bi1/2Na1/2)TiO3 Ceramics

2007 ◽  
Vol 350 ◽  
pp. 93-96 ◽  
Author(s):  
Yuji Hiruma ◽  
Yoshinori Watanabe ◽  
Hajime Nagata ◽  
Tadashi Takenaka
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Electrical Measurement ◽  
Transition Temperatures ◽  
Maximum Dielectric Constant ◽  
Phase Transition Temperatures ◽  
Temperature Dependences ◽  
A Site ◽  
The Relationship

The phase transition temperatures of divalent and trivalent ions substituted (Bi1/2Na1/2)TiO3 ceramics were investigated in detail by electrical measurement. BNT ceramics substituted by divalent (Ca2+, Sr2+ and Ba2+) and trivalent (La3+, Nd3+, Ho3+ and Yb3+) ions were prepared by conventional ceramic fabrication process. For these ceramics, the depolarization temperature, Td, the rhombohedral-tetragonal phase transition temperature, TR-T, and the temperature of the maximum dielectric constant, Tm, were determined on the basis of the temperature dependences of dielectric and piezoelectric properties. In this study, we demonstrated the relationship between phase transition temperature and ionic radius of ions substituted in the A-site of BNT ceramics.

Study on Preparation and Sensitive Properties of Polyethylene Glycol (PEG) / Polyvinyl Alcohol (PVA) Thermo-Sensitive Hydrogel

2011 ◽  
Vol 306-307 ◽  
pp. 41-45
Author(s):  
Mei Zhang ◽  
Tian Yu Xu ◽  
Yan Cui ◽  
Da Hui Sun
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Melting Point ◽  
Phase Transition Temperature ◽  
Phase Change Materials ◽  
Swelling Properties ◽  
Hydrogel Swelling ◽  
Polymer Framework ◽  
Dsc Method ◽  
The Relationship

Thermo-sensitive hydrogel have broad application prospects in biochemistry, medicine and other fields. In this paper, PEG as low melting point polymer was grafted at PVA which was as polymer framework of high melting point by copolymerization, a serials of new reversible phase-change materials were obtained and thermo-sensitive hydrogel were prepared because of their swelling properties. The hydrogel swelling behavior was analyzed, thermo-sensitive properties analysis was made by using DSC method, xerogel phase transition behavior was also studied and through which the relationship between PEG phase transition temperature and thermo-sensitive behaviors of the hydrogel was studied. The results showed that the thermo-sensitive hydrogel phase transition temperature was in the range of 36.3~43°C,and the phase transition temperature and the temperature sensitivity existed a certain relationship.

The structure of membranes and membrane proteins embedded in amorphous ice

1992 ◽  
Vol 50 (1) ◽  
pp. 432-433
Author(s):  
Uwe Lücken ◽  
Joachim Jäger
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Membrane Proteins ◽  
Phase Transition Temperature ◽  
Lipid Vesicles ◽  
Freezing Stress ◽  
Amorphous Ice ◽  
Different Temperatures ◽  
Band Pass ◽  
Lipid Polymorphism

TEM imaging of frozen-hydrated lipid vesicles has been done by several groups Thermotrophic and lyotrophic polymorphism has been reported. By using image processing, computer simulation and tilt experiments, we tried to learn about the influence of freezing-stress and defocus artifacts on the lipid polymorphism and fine structure of the bilayer profile. We show integrated membrane proteins do modulate the bilayer structure and the morphology of the vesicles.Phase transitions of DMPC vesicles were visualized after freezing under equilibrium conditions at different temperatures in a controlled-environment vitrification system. Below the main phase transition temperature of 24°C (Fig. 1), vesicles show a facetted appearance due to the quasicrystalline areas. A gradual increase in temperature leads to melting processes with different morphology in the bilayer profile. Far above the phase transition temperature the bilayer profile is still present. In the band-pass-filtered images (Fig. 2) no significant change in the width of the bilayer profile is visible.

scholarly journals Study of physical properties of a ferrimagnetic spinel Cu1.5Mn1.5O4: spin dynamics, magnetocaloric effect and critical behavior

RSC Advances ◽  
2021 ◽  
Vol 11 (41) ◽  
pp. 25664-25676
Author(s):  
Abir Hadded ◽  
Jalel Massoudi ◽  
Sirine Gharbi ◽  
Essebti Dhahri ◽  
A. Tozri ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Physical Properties ◽  
Magnetocaloric Effect ◽  
Phase Transition Temperature ◽  
Magnetic Phase Transition ◽  
Critical Behavior ◽  
Magnetic Phase ◽  
Spin Dynamics ◽  
Critical Behaviour

The present work reports a detailed study of the spin dynamics, magnetocaloric effect and critical behaviour near the magnetic phase transition temperature, of a ferrimagnetic spinel Cu1.5Mn1.5O4.

scholarly journals Modulating the phase transition temperature of giant magnetocaloric thin films by ion irradiation

2017 ◽  
Vol 1 (6) ◽  
Author(s):  
S. Cervera ◽  
M. Trassinelli ◽  
M. Marangolo ◽  
C. Carrétéro ◽  
V. Garcia ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Ion Irradiation
Sign in / Sign up

Export Citation Format

Share Document