Structure of Vulcanized and Unvulcanized SBR/BR Blends

1969 ◽  
Vol 42 (4) ◽  
pp. 1009-1013 ◽  
Author(s):  
N. Yoshimura ◽  
K. Fujimoto
Keyword(s):  
Dielectric Loss ◽  
Temperature Dependence ◽  
Loss Tangent ◽  
Dynamic Modulus ◽  
Phase Contrast ◽  
The Other ◽  
Other Hand ◽  
Styrene Content ◽  
Tan Δ ◽  
Phase Contrast Micrographs

Abstract Mainly from the temperature dependence of transitions in dynamic modulus, loss tangent, and dielectric loss, associated with microbrownian motions of main chains, it was concluded that blends of NR and BR are microheterogeneous and those of SBR and BR are almost microhomogeneous. Furthermore, even SBR/BR blends tended to be heterogeneous if the styrene content in SBR was increased. On the other hand, unvulcanized SBR/BR blends have been reported to be heterogeneous from observation of phase contrast micrographs. To investigate this vulcanization effect further, measurements of temperature dependence of dynamic modulus and tan δ of unvulcanized blends were compared with those of vulcanized blends.

Dislocations in diamond and the origin of trigones

1964 ◽  
Vol 278 (1373) ◽  
pp. 234-242 ◽  
Keyword(s):  
Phase Contrast ◽  
Natural Diamond ◽  
The Other ◽  
Burgers Vector ◽  
X Ray ◽  
Etch Pit ◽  
Other Hand ◽  
Vector Orientation

Combined X-ray topographic and phase-contrast micrographic studies of natural diamond octahedral faces show that pyramidal trigons are always associated with dislocation outcrops. No dislocations outcrop at flat-bottomed trigons. On the other hand, absence of trigons does not necessarily imply absence of outcropping dislocations. The X-ray evidence strongly supports the etch-pit hypothesis for the origin of trigons. A dependence of trigon pit slope upon the Burgers vector orientation of its associated dislocation was not conclusively demonstrated.

Interactions of LO Phonons with Bound Excitons in Homoepitaxial GaN

1997 ◽  
Vol 482 ◽  
Author(s):  
K. P. Koron ◽  
A. Wysmolek ◽  
J. M. Baranowskil ◽  
K. Pakul ◽  
J. P. Bergman ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
The Other ◽  
Direct Influence ◽  
Neutral Donor ◽  
Phonon Replica ◽  
Temperature Range ◽  
Other Hand ◽  
Order Of Magnitude ◽  
Neutral Acceptor

AbstractPhotoluminescence connected with excitons and their phonon replicas in undoped homoepitaxial MOCVD grown GaN layers have been studied in the temperature range 2 - 100 K. It is shown that the coupling between LO phonons and neutral acceptor bound excitons (ABE) is much stronger than the coupling between LO phonons and neutral donor bound excitons (DBE). In spite that emission due the DBE no-phonon is one order of magnitude stronger than the ABE one, the predominant feature of the first LO phonon replica of the excitonic structures is related to the ABE. It is argued that this fact is connected with delocalization of the acceptor wavefunction in the k-space which leads to a higher number of interacting LO phonons in the first replica. On the other hand, the second LO phonon replica of the excitonic structures is predominantly connected with the DBE. In the case of two LO phonons interacting with bound excitons the k - conservation has not so direct influence. In addition, the temperature dependence of LO phonon replicas and their kinetics in ps regime are also reported.

Effects of alloying elements on thermoelectric properties of ReSi1.75

2003 ◽  
Vol 793 ◽  
Author(s):  
Min Wook Oh ◽  
Jia-Jun Gu ◽  
Kosuke Kuwabara ◽  
Haruyuki Inui
Keyword(s):  
Electrical Resistivity ◽  
Temperature Dependence ◽  
Thermoelectric Property ◽  
Thermoelectric Properties ◽  
Binary Alloy ◽  
Figure Of Merit ◽  
The Other ◽  
Alloying Elements ◽  
Dimensionless Figure Of Merit ◽  
Other Hand

ABSTRACTS:The thermoelectric properties as well as microstructure of binary and some ternary ReSi1.75 have been investigated. Binary ReSi1.75 exhibits a nice thermoelectric property as exemplified by the high value of dimensionless figure of merit (ZT) of 0.70 at 800 °C when measured along [001], although the ZT value along [100] is just moderately high. Mo substitution for Re in ReSi1.75 considerably increases the ZT value along [001] because of the decreased electrical resistivity, while the property improvement is not significant along [100]. On the other hand, Al and Ge substitutions for Si in ReSi1.75 considerably increase the ZT value along [100]. This is also because of the decreased electrical resistivity. When Al is added to ReSi1.75, the value of electrical resistivity is significantly reduced when compared to the binary counterpart and the temperature dependence of electrical resistivity changes from of semiconductor for the binary alloy to of metal for the Al-added alloys.

Effect of the Annealing Temperature on Dielectric Properties of Bi1.5Zn1.0Nb1.5O7 Films Prepared by MOCVD

2008 ◽  
Vol 388 ◽  
pp. 175-178
Author(s):  
Hiroshi Funakubo ◽  
Shingo Okaura ◽  
Muneyasu Suzuki ◽  
Hiroshi Uchida ◽  
Seiichiro Koda
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Temperature Coefficient ◽  
Annealing Temperature ◽  
Relative Dielectric Constant ◽  
Fused Silica ◽  
The Other ◽  
Other Hand ◽  
Silica Substrates

Effect of annealing temperature on the dielectric properties of Bi1.5Zn1.0Nb1.5O7 films prepared on (111)Pt//(001)Al2O3 and (111)Pt/fused silica substrates by MOCVD was investigated. The tunability and the inverse of the dielectric loss [1/ (tan )] increased with increasing annealing temperature. Relative dielectric constant and temperature coefficient of the capacitance (TCC) increased with the crystallinity of the films. On the other hand, (1/tan ) was independent of the crystallinity of the films, but was dramatically increased by the annealing.

Phase contrast and scanning electron microscopy of a soil amoeba, Hartmannella glebae

1986 ◽  
Vol 44 ◽  
pp. 300-301
Author(s):  
J. Upadhyay ◽  
M. J. Schurr ◽  
R. J. Lesseps
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Current Literature ◽  
Phase Contrast ◽  
The Other ◽  
Other Hand ◽  
As Species ◽  
Soil Amoeba ◽  
Scanning Electron

The genera Hartmannella and Acanthamoeba have been controversial. Some species of Acanthamoeba have been cited as species of Acanthamoeba, Mayorella, or Amoeba and a confusing lack of agreement persists in current literature. The genus Hartmannella was redefined by Page in 1967 to include those species which assumed a simple monopodial, limax-like form during locomotion and, where known, the cysts were smooth-walled and rounded with no opercula. The genus Acanthamoeba, on the other hand, possessed tapering, hyaline pseudopods (acanthopodia) and a cyst made up of an ectocyst and a polyhedral or stellate endocyst, with excystment by removal of opercula.

Study of Polymer Blends. II. Blending SBR Varying in Styrene Content with Polybutadiene

1968 ◽  
Vol 41 (5) ◽  
pp. 1109-1121 ◽  
Author(s):  
K. Fujimoto ◽  
N. Yoshimura
Keyword(s):  
Dielectric Loss ◽  
Physical Properties ◽  
Polymer Blends ◽  
Dynamic Characteristics ◽  
Phase Contrast ◽  
Phase Contrast Microscopy ◽  
Polymer Solubility ◽  
Contrast Microscopy ◽  
Styrene Content

Abstract For this study of effect of SBR styrene content on blends of SBR and BR, polymer solubility was investigated by phase contrast microscopy, dielectric loss, and dynamic characteristics. Physical properties of blended rubber were also measured.

Effect of feldspar filler on physical and dynamic properties of SBR/CB based tire tread compounds: Effect of addition method of silane coupling agent

2021 ◽  
pp. 009524432110061
Author(s):  
Neşe Kaynak ◽  
Sinan Şen
Keyword(s):  
Hybrid Composites ◽  
Dynamic Properties ◽  
Rolling Resistance ◽  
The Other ◽  
Inorganic Filler ◽  
Addition Method ◽  
Rubber Mixture ◽  
Other Hand ◽  
Damping Parameter ◽  
Tan Δ

In this work, the effects of using feldspar (FLD) as an alumina-silicate inorganic filler, with carbon black (CB) as a novel binary filler system, on the properties of SBR compounds were investigated for tire applications. The bis(triethoxysilylpropyl) disulfide (TESPD) was used for modification of FLD. The SBR hybrid composites were produced by replacing 10 phr of CB filler with neat FLD and functionalized FLD (F-FLD). The TESPD was added directly to the rubber mixture including neat FLD. The SBR composite which has only CB filler (50CB) was found to have the highest damping parameter (tan δ) value at 60°C. On the other hand, the composites loaded with the CB and the FLD fillers exhibited relatively lower tan δ at the same temperature showing lower rolling resistance meaning better fuel saving performance. The lowest rolling resistance was achieved for the 40CB-10F-FLD most probably due to its stronger interaction with the SBR elastomer molecules through the silane agent-assisted crosslinks of the F-FLD. As another dynamic property, the storage moduli at −20°C were found to be lower for the SBR hybrid composites as compared to that of the 50CB composite, exhibiting enhanced winter traction performance of the composites having FLD filler together with CB. The composites containing only 10 phr of FLD and F-FLD, on the other hand, exhibited very low tensile strength values which are not acceptable for tire tread materials.

DIELECTRIC PROPERTIES OF Li-Sb FERRITES

2005 ◽  
Vol 19 (18) ◽  
pp. 899-905 ◽  
Author(s):  
SHIVAJI CHONGTHAM ◽  
SUMITRA PHANJOUBAM ◽  
H. N. K. SARMA ◽  
RADHAPIYARI LAISHRAM ◽  
CHANDRA PRAKASH
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Room Temperature ◽  
Substitution Level ◽  
Higher Temperature ◽  
Tan Δ ◽  
Almost All ◽  
Frequency Curves

Dielectric properties such as dielectric constant (ε′) and dielectric loss tangent ( tan δ) of Li 0.5+x Fe 2.5-2x Sb x O 4 ferrites, 0.10≤ x ≤0.30 in steps of 0.05 have been investigated as a function of composition, frequency and temperature. The dielectric constant showed dispersion with frequency in the range of 100 Hz–1 MHz. Peaks were observed in the tan δ versus frequency curves for almost all the samples. The temperature variation of dielectric constant for the different samples was studied at 10 kHz in the temperature range from room temperature to 433 K. Peaks were observed for some of the samples. The peaks were seen to shift towards higher temperature region as the substitution level increases. The mechanisms involved in the processes are discussed in this paper.

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