Systematic variation of thiophene substituents in photochromic spiropyrans

2017 ◽  
Vol 16 (7) ◽  
pp. 1057-1062
Author(s):  
Dushanthi S. Dissanayake ◽  
Gregory T. McCandless ◽  
Mihaela C. Stefan ◽  
Michael C. Biewer
Keyword(s):  
Decay Rate ◽  
Half Life ◽  
Reverse Reaction ◽  
Systematic Variation ◽  
Synthetic Method ◽  
Thermal Decay

A new synthetic method was developed to incorporate spiropyran into thiophene based materials via a conjugated pathway. As the number of thiophene units increased, the thermal decay rate of the reverse reaction decreased in methanol, thus increasing the half-life of merocyanine.

THE IDENTIFICATION AND HALF LIVES OF FISSION-PRODUCT Rb92 AND Rb93

1960 ◽  
Vol 38 (12) ◽  
pp. 1614-1622 ◽  
Author(s):  
K. Fritze ◽  
T. J. Kennett
Keyword(s):  
Fission Product ◽  
Decay Rate ◽  
Half Life ◽  
Fission Products ◽  
Strontium Isotopes ◽  
A Value ◽  
Γ Ray ◽  
Rubidium Isotopes

The existence of two new rubidium isotopes, Rb92 and Rb93, has been established and their half lives measured. The half lives of these short-lived fission products were determined using a technique of timed precipitations. The values obtained for Rb92 and Rb93 were 5.3 ± 0.5 sec and 5.6 ± 0.5 sec respectively. The half lives of the strontium and yttrium daughters were also determined. The strontium isotopes were studied by observing the decay rate of a characteristic γ-ray peak. For Sr92, the decay of the 1.37-Mev line gave a value of 2.71 ± 0.02 hr. A γ-ray peak at 590 kev, which was found to be associated with Sr93, decayed with a half life of 7.54 ± 0.06 min. The half lives of the yttrium daughters were determined by β counting. The values found for Y92 and Y93 were 3.53 ± 0.02 hr and 10.1 ± 0.1 hr respectively.

scholarly journals Two ways for finding the thermal decay rate at weak friction

2019 ◽  
Vol 1260 ◽  
pp. 092001
Author(s):  
M V Chushnyakova ◽  
I I Gontchar ◽  
A I Blesman
Keyword(s):  
Decay Rate ◽  
Thermal Decay

scholarly journals Remotely sensed thermal decay rate: an index for vegetation monitoring

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
S. S. Kumar ◽  
L. Prihodko ◽  
B. M. Lind ◽  
J. Anchang ◽  
W. Ji ◽  
...  
Keyword(s):  
Decay Rate ◽  
Remotely Sensed ◽  
Thermal Decay ◽  
Vegetation Monitoring

Dynamic Coercivity and Thermal Decay of Magnetic Media

1998 ◽  
Vol 517 ◽  
Author(s):  
Kurt Rubin ◽  
Jason Goldberg ◽  
Hal Rosen ◽  
Ernesto Marinero ◽  
Mary Doemer ◽  
...  
Keyword(s):  
Time Dependence ◽  
Decay Rate ◽  
Experimental Technique ◽  
Linear Density ◽  
Magnetic Media ◽  
Magnetic Transitions ◽  
Thermal Decay ◽  
Thermally Induced ◽  
The Media ◽  
Short Times

AbstractThermally induced decay of longitudinally recorded magnetic transitions is measured on a spin-stand. The decay rate increases with increased linear density and decreases with increased media coercivity. A new spin-stand experimental technique has been developed which allows measurements of the time dependence of the media coercivity as a function of write times spanning short times characteristic of write times in drives to long times associated with VSM measurements. The ratio of long to short write time coercivity was larger for media which are thermally unstable.

Photochromism of spiroindolinonaphthoxazine. I. Photophysical properties

1983 ◽  
Vol 61 (2) ◽  
pp. 300-305 ◽  
Author(s):  
Nori Y. C. Chu
Keyword(s):  
Decay Rate ◽  
Photophysical Properties ◽  
Ultraviolet Region ◽  
Colored Form ◽  
Thermal Decay ◽  
Triplet Energy ◽  
Absorption Bands ◽  
Different Temperatures ◽  
Transfer Method ◽  
Triplet Energy Transfer

A solution of spiroindolinonaphthoxazine in a common organic solvent shows profound photochromic effect. The colorless form in ethanol displays three absorption bands (~320, 235, 203 nm) in the ultraviolet region of the spectrum. The absorption spectrum of the colored metastable form shows two prominent absorption peaks at 612 and 578 nm. The triplet state energy level of the colorless form is estimated to be in the range from 2.4 × 104 to 2.1 × 104 cm−1 by the triplet–triplet energy transfer method. There exists a thermal equilibrium between the colorless and colored forms. From the measurement of absorbance of the colored form at different temperatures, the standard enthalpy of equilibrium is obtained (ΔH0 = 1500 cm−1). The thermal decay of the colored form to the colorless form depends strongly on temperature. The decay rate increases three times for every 10 °C increase in temperature. From these temperature dependence studies of the thermal decay rate, the thermal energy barrier for the colored metastable state to decay to the colorless form is determined to be 6.9 × 103 cm−1.

Half-life of rhenium: geologic and cosmologic ages

1984 ◽  
Vol 62 (1) ◽  
pp. 15-20 ◽  
Author(s):  
Stanley N. Naldrett
Keyword(s):  
Organic Compound ◽  
Decay Rate ◽  
Liquid Scintillation Counting ◽  
Half Life ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Beta Emission

The transition by beta emission of 187Re to 187Os would offer an attractive method of determining geologic and cosmologic ages if the decay rate of 187Re was known. An improvement in the determination of the decay rate has been accomplished using an organic compound of rhenium in liquid scintillation counting that is monitored by standards of other pure beta emitting isotopes. The half-life of 187Re is estimated to be (3.5 ± 0.4) × 1010 yr.

scholarly journals Half-life measurement of 7Be in host beryllium metal

2011 ◽  
Vol 1 (1) ◽  
pp. 101-104
Author(s):  
T. Ohtsuki ◽  
K. Hirose ◽  
K. Ohno ◽  
T. Morisato
Keyword(s):  
Decay Rate ◽  
Liquid Helium ◽  
Electron Density ◽  
Electron Capture ◽  
Half Life ◽  
Lithium Fluoride ◽  
Room Temperature ◽  
Life Measurement ◽  
Beryllium Metal

AbstractThe decay rate of an electron-capture nucleus is proportional to the electron density at the nucleus. To see how the decay rate is changed by artificially, we have measured the half-life of7Be in beryllium(Be) metal at room temperature (T=293 K) and at close to the temperature of liquid helium (T=5 K). We found that the half-life of7Be in Be metal at T=293 K is 53.25 ± 0.04 d, which is slightly longer than those in the hosts of graphite, lithium fluoride and other minerals, surveyed so far. Furthermore, that at T=5 K is 53.39 ± 0.04 d, which is 0.26% longer than that at T =293 K.

Peculiarities of parabolic-barrier penetrability and thermal decay rate with the quantum diffusion approach

2011 ◽  
Vol 83 (6) ◽  
Author(s):  
R. A. Kuzyakin ◽  
V. V. Sargsyan ◽  
G. G. Adamian ◽  
N. V. Antonenko
Keyword(s):  
Decay Rate ◽  
Quantum Diffusion ◽  
Thermal Decay
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