scholarly journals Strong temperature dependence of water reorientation in hydrophobic hydration shells

2009 ◽  
Vol 130 (21) ◽  
pp. 214511 ◽  
Author(s):  
C. Petersen ◽  
K.-J. Tielrooij ◽  
H. J. Bakker
Keyword(s):  
Temperature Dependence ◽  
Hydrophobic Hydration ◽  
Strong Temperature Dependence ◽  
Hydration Shells

Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

1982 ◽  
Vol 40 ◽  
pp. 78-79
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser
Keyword(s):  
Electron Beam ◽  
Fatty Acid ◽  
Inelastic Scattering ◽  
Temperature Dependence ◽  
Structural Damage ◽  
Direct Result ◽  
Second Step ◽  
Strong Temperature Dependence ◽  
Electron Dose ◽  
Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

scholarly journals Temperature-Driven Spin Reorientation Transition in CoPt/AlN Multilayer Films

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
Wupeng Cai ◽  
Shinji Muraishi ◽  
Ji Shi ◽  
Yoshio Nakamura ◽  
Wei Liu ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Mean Field ◽  
Multilayer Films ◽  
Spin Reorientation ◽  
Strong Temperature Dependence ◽  
Mean Field Model ◽  
Spin Reorientation Transition ◽  
Magnetoelastic Effect ◽  
Out Of Plane ◽  
Interface Anisotropy

Spin reorientation transition phenomena from out-of-plane to in-plane direction with increasing temperature are observed for the 500°C annealed CoPt/AlN multilayer films with different CoPt layer thicknesses. CoPt-AlN interface and volume anisotropy contributions, favoring out-of-plane and in-plane magnetization, respectively, are separately determined at various temperatures. Interface anisotropy exhibits much stronger temperature dependence than volume contribution, hence the temperature-driven spin reorientation transition occurs. Interface anisotropy in this work consists of Néel interface anisotropy and magnetoelastic effect. Magnetoelastic effect degrades rapidly and changes its sign from positive to negative above 200°C, because of the involvement of stress state in CoPt films with temperature. By contrast, Néel interface anisotropy decays slowly, estimated from a Néel mean field model. Thus, the strong temperature dependence of CoPt-AlN interface anisotropy is dominated by the change of magnetoelastic effect.

scholarly journals Thermochromism of Highly Luminescent Photopolymer Flexible Films Based On Eu (III) Salts Confined in Polysulfone

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5394
Author(s):  
Mani Outis ◽  
João Paulo Leal ◽  
Maria Helena Casimiro ◽  
Bernardo Monteiro ◽  
Cláudia Cristina Lage Pereira
Keyword(s):  
Thermal Stability ◽  
Ionic Liquid ◽  
Melting Point ◽  
Quantum Yield ◽  
Thermal Behavior ◽  
Temperature Dependence ◽  
Strong Temperature Dependence ◽  
Host Matrix ◽  
Flexible Films ◽  
First Time

Here we discuss the influence of two different cations on the emissive properties of the highly emissive [Eu(fod)4]− anion. The studied Eu(III) salts were [C16Pyr][Eu(fod)4] (1), and the previously reported [Chol][Eu(fod)4]. C16Pyr stands for N-cetylpyridinium, Chol for cholinium and fod for 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyloctane-4,6-dionate. 1 is classified as ionic liquid, with melting point close to 60 °C, and presented a luminescence quantum yield of (ϕ) 100%. Ultrabright emissive photopolymers were obtained for the first time using polysulfone as the host matrix. The films were prepared with incorporation of 10% (w/w) of 1 and [Chol][Eu(fod)4] in the polymeric matrix, which improved its thermal stability. Additionally, the luminescence of CholEu(fod)4/PSU presented a strong temperature dependence with a ratiometric thermal behavior.

Temperature Effect on Phase-Transition Radiation of Water

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
M. Q. Brewster ◽  
K.-T. Wang ◽  
W.-H. Wu ◽  
M. G. Khan
Keyword(s):  
Phase Transition ◽  
Phase Change ◽  
Temperature Dependence ◽  
Transition Probability ◽  
Cloud Droplet ◽  
Radiation Absorption ◽  
Effect Of Temperature ◽  
Strong Temperature Dependence ◽  
Atmospheric Windows ◽  
Radiative Phase

Infrared radiation associated with vapor-liquid phase transition of water is investigated using a suspension of cloud droplets and mid-infrared (IR) (3–5 μm) radiation absorption measurements. Recent measurements and Monte Carlo (MC) modeling performed at 60 °C and 1 atm resulted in an interfacial radiative phase-transition probability of 5 × 10−8 and a corresponding surface absorption efficiency of 3–4%, depending on wavelength. In this paper, the measurements and modeling have been extended to 75 °C in order to examine the effect of temperature on water's liquid-vapor phase-change radiation. It was found that the temperature dependence of the previously proposed phase-change absorption theoretical framework by itself was insufficient to account for observed changes in radiation absorption without a change in cloud droplet number density. Therefore, the results suggest a strong temperature dependence of cloud condensation nuclei (CCN) concentration, i.e., CCN increasing approximately a factor of two from 60 °C to 75 °C at near saturation conditions. The new radiative phase-transition probability is decreased slightly to 3 × 10−8. Theoretical results were also calculated at 50 °C in an effort to understand behavior at conditions closer to atmospheric. The results suggest that accounting for multiple interface interactions within a single droplet at wavelengths in atmospheric windows (where anomalous IR radiation is often reported) will be important. Modeling also suggests that phase-change radiation will be most important at wavelengths of low volumetric absorption, i.e., atmospheric windows such as 3–5 μm and 8–10 μm, and for water droplets smaller than stable cloud droplet sizes (<20 μm diameter), where surface effects become relatively more important. This could include unactivated, hygroscopic aerosol particles (not CCN) that have absorbed water and are undergoing dynamic evaporation and condensation. This mechanism may be partly responsible for water vapor's IR continuum absorption in these atmospheric windows.

STUDY OF MOLECULAR MOTIONS IN TWO LIQUID CRYSTAL FORMING COMPOUNDS EMPLOYING PLS

2006 ◽  
Vol 20 (14) ◽  
pp. 2019-2034 ◽  
Author(s):  
K. CHANDRAMANI SINGH ◽  
M. SHARMA ◽  
P. C. JAIN
Keyword(s):  
Liquid Crystal ◽  
Temperature Dependence ◽  
Liquid Crystalline ◽  
Positron Lifetime ◽  
Strong Temperature Dependence ◽  
Molecular Motions ◽  
Temperature Dependent ◽  
Slow Cooling ◽  
Positron Lifetime Spectroscopy ◽  
Motion Studies

Results of molecular motion studies carried out in two liquid crystal forming compounds n-p-cyano-p-hexyloxybiphenyl (M18) and n-p-ethoxybenzylidene-p-butylaniline (EBBA) using positron lifetime spectroscopy (PLS) are presented. Temperature dependent positron lifetime measurements have been performed in each compound during the heating cycle of samples prepared by either quenching or slow cooling from the respective liquid crystalline phase of the compounds. In both the compounds, behaviors of the quenched and slow cooled samples are found to be different. The material in the quenched sample, unlike the slow-cooled sample, exhibits strong temperature dependence before it undergoes a glass transition. In each case, the temperature dependence of o-Ps pick-off lifetime in the quenched sample shows broad peaks at various characteristic temperatures. These peaks have been attributed to various intra- and inter-molecular motions associated with these compounds. The characteristic frequencies of some of the modes observed in the present work agree well with the literature reported values obtained from FIR and Raman studies. The present study demonstrates the usefulness of PLS in the study of molecular motions.

Strong temperature dependence of thec-axis gap parameter ofBi2Sr2CaCu2O8+δintrinsic Josephson junctions

1996 ◽  
Vol 53 (14) ◽  
pp. R8887-R8890 ◽  
Author(s):  
A. Yurgens ◽  
D. Winkler ◽  
N. V. Zavaritsky ◽  
T. Claeson
Keyword(s):  
Temperature Dependence ◽  
Josephson Junctions ◽  
Strong Temperature Dependence ◽  
Gap Parameter

Ozonation of bromide-containing drinking waters:a delicate balance between disinfection and bromate formation

2000 ◽  
Vol 41 (7) ◽  
pp. 53-59 ◽  
Author(s):  
U. von Gunten ◽  
U. Pinkernell
Keyword(s):  
Temperature Dependence ◽  
Low Temperatures ◽  
The Other ◽  
Ozone Exposure ◽  
Oh Radicals ◽  
Strong Temperature Dependence ◽  
Control Options ◽  
The One ◽  
Kinetics Of ◽  
Ozonation Process

The occurrence of Cryptosporidium in raw waters and bromate formation during ozonation of bromide-containing waters leads to a difficult optimisation of ozonation processes. On the one hand inactivation of Cryptosporidium requires high ozone exposures, on the other hand under these conditions bromate formation is favored. In order to overcome this problem we need information about (i) the oxidant concentrations (ozone and OH radicals) during an ozonation process, (ii) kinetics of the inactivation of Cryptosporidium, (iii) kinetics and mechanism of bromate formation, and (iv) the reactor hydraulics. The strong temperature dependence of the inactivation of Cryptosporidium which results in a higher ozone exposure (time-integrated action of ozone) at low temperatures makes it more difficult to fulfil disinfection and bromate standards at low temperatures. Underthese conditions control options for bromate formation can be applied. Depressionof pH and addition of ammonia have been selected to be the best options. For a given ozone exposure both measures lead to a reduction of bromate formation in the order of 50%.

Marked Temperature Dependence of the Platelet Calcium Signal Induced by Human von Willebrand Factor

Blood ◽  
1999 ◽  
Vol 94 (1) ◽  
pp. 199-207 ◽  
Author(s):  
John C. Kermode ◽  
Qi Zheng ◽  
Elizabeth P. Milner
Keyword(s):  
Arachidonic Acid ◽  
Temperature Dependence ◽  
Von Willebrand Factor ◽  
Thromboxane A2 ◽  
Underlying Mechanism ◽  
Calcium Signal ◽  
Free Calcium ◽  
Strong Temperature Dependence ◽  
Von Willebrand ◽  
Willebrand Factor

Interaction of von Willebrand factor (vWF) with the platelet is essential to hemostasis when vascular injury occurs. This interaction elevates the intracellular free calcium concentration ([Ca2+]i) and promotes platelet activation. The present study investigated the temperature dependence of vWF-induced [Ca2+]i signaling in human platelets. The influence of temperature can provide invaluable insight into the underlying mechanism. Platelet [Ca2+]i was monitored with Fura-PE3. Ristocetin-mediated binding of vWF induced a transient platelet [Ca2+]i increase at 37°C, but no response at lower temperatures (20°C to 25°C). This temperature dependence could not be attributed to a reduction in vWF binding, as ristocetin-mediated platelet aggregation and agglutination were essentially unaffected by temperature. Most other platelet agonists (U-46619, -thrombin, and adenosine 5′-diphosphate [ADP]) induced a [Ca2+]isignal whose amplitude did not diminish at lower temperatures. The [Ca2+]i signal in response to arachidonic acid, however, showed similar temperature dependence to that seen with vWF. Assessment of thromboxane A2 production showed a strong temperature dependence for metabolism of arachidonic acid by the cyclo-oxygenase pathway. vWF induced thromboxane A2production in the platelet. Aspirin treatment abolished the vWF-induced [Ca2+]i signal. These observations suggest that release of arachidonic acid and its conversion to thromboxane A2 play a central role in vWF-mediated [Ca2+]i signaling in the platelet at physiological temperatures.

scholarly journals Strong temperature dependence of antiferromagnetic coupling in CoFeB/Ru/CoFeB

2007 ◽  
Vol 78 (6) ◽  
pp. 67002 ◽  
Author(s):  
N Wiese ◽  
T Dimopoulos ◽  
M Rührig ◽  
J Wecker ◽  
G Reiss ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Antiferromagnetic Coupling ◽  
Strong Temperature Dependence

scholarly journals A re-evaluation of the ClO/Cl<sub>2</sub>O<sub>2</sub> equilibrium constant based on stratospheric in-situ observations

2005 ◽  
Vol 5 (3) ◽  
pp. 693-702 ◽  
Author(s):  
M. von Hobe ◽  
J.-U. Grooß ◽  
R. Müller ◽  
S. Hrechanyy ◽  
U. Winkler ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Equilibrium Constant ◽  
Thermal Equilibrium ◽  
Loss Rate ◽  
Equilibrium Constants ◽  
The Arctic ◽  
Strong Temperature Dependence ◽  
Atmospheric Models ◽  
Ozone Loss

Abstract. In-situ measurements of ClO and its dimer carried out during the SOLVE II/VINTERSOL-EUPLEX and ENVISAT Validation campaigns in the Arctic winter 2003 suggest that the thermal equilibrium between the dimer formation and dissociation is shifted significantly towards the monomer compared to the current JPL 2002 recommendation. Detailed analysis of observations made in thermal equilibrium allowed to re-evaluate the magnitude and temperature dependence of the equilibrium constant. A fit of the JPL format for equilibrium constants yields KEQ=3.61x10-27exp(8167/T), but to reconcile the observations made at low temperatures with the existing laboratory studies at room temperature, a modified equation, KEQ=5.47x10-25(T/300)-2.29exp(6969/T), is required. This format can be rationalised by a strong temperature dependence of the reaction enthalpy possibly induced by Cl2O2 isomerism effects. At stratospheric temperatures, both equations are practically equivalent. Using the equilibrium constant reported here rather than the JPL 2002 recommendation in atmospheric models does not have a large impact on simulated ozone loss. Solely at large zenith angles after sunrise, a small decrease of the ozone loss rate due to the ClO dimer cycle and an increase due to the ClO-BrO cycle (attributed to the enhanced equilibrium ClO concentrations) is observed, the net effect being a slightly stronger ozone loss rate.

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