Spectral Theory of Perturbative Decays

We propose a complex approach to evaluating afunction sum of two noncommuting non-Hermitianoperators. We propose an explicit expansion of theevolution operator in the case of the neutral K-mesonsystem influenced by an external interaction. Theimportance is pointed out of considering the algebraicexpansion of the time evolution operator whenever thedynamics decouples the internal transitions andcenter-of-mass motion.     

Direct measurement of the thermal rate coefficient for electron attachment to ozone in the gas phase, 300-550 K: implications for the ionosphere

Attachment of thermal electrons to O3 was studied in 133 Pa He between 300-550 K; the process is extremely inefficient. The rate coefficient increases sharply with temperature from 0.9 to 5 x 10(-11) cm(3) s(-1) (+/-30%) and comparison to kinetic energy measurements suggests internal energy can drive the reaction. These determinations account for competing processes of diffusion, recombination, and electron detachment reactions, and imply that no significant zero-energy resonance cross section exists, contradicting recent electron-beam results that call for substantial revision of ionospheric models.     

Aspect-ratio dependent oscillatory thermocapillary convection in the floating half zone

The dependency of the critical Marangoni number on the geometrical aspect ratio of the floating half zone is essential to predict the onset of oscillatory thermocapillary convection.The experimental studies in the microgravity conditions on floating half zones of several centimeters in diameter have predicted that the critical Marangoni number increases with the increasing aspect ratio,and the terrestrial experimental studies have predicted the contradictory conclusion for floating half zones of several mil...     

Non-Gravitational Effects with Density-Matching in Evaluating the Influence of Sedimentation on Colloidal Coagulation

The method of density matching between the solid and liquid phases is often adopted to effectively eliminate the effect of sedimentation of suspensions in studies on dynamic behaviour of a colloidal system. However, the associated changes in the solvent composition may bring side effects to the properties investigated and therefore might lead to a faulty conclusion if the relevant correction is not made. To illustrate the importance of this side effect, we present an example of the sedimentation influence on the coagulation rate of suspensions of 2μm （diameter） polystyrene. The liquid mixtures, in the proper proportions of water （H2O）, deuterium oxide （D2O） and methanol （MeOH） as the liquid phase, density-matched and unmatched experiments are performed. Besides the influence of viscosity, the presence of methanol in solvent media, used to enhance the sedimentation effect, causes significant changes （reduction） in rapid coagulation rates compared to that in pure water. Without the relevant corrections for those non-gravitational factors it seems that gravitational sedimentation would retard the coagulation. The magnitude of the contribution from the non-gravitational factor is quantitatively determined, making the relevant correction possible. After necessary the influence of the sedimentation on coagulation rates at corrections for all factors, our experiments show that the initial stage of the coagulation is not observable.     

Electron attachment to propargyl chloride, 305-540 K

Electron attachment to propargyl chloride (HC≡C-CH(2)Cl) was studied in a flowing-afterglow Langmuir-probe apparatus from 305 to 540 K. The sole ion product in this temperature range is Cl(-). Electron attachment is very inefficient, requiring correction for a competing process of electron recombination with molecular cations produced in reaction between Ar(+) and propargyl chloride and subsequent ion-molecule reactions. The electron attachment rate coefficient was measured to be 1.6×10(-10)cm(3)?s(-1) at 305 K and increased to 1.1×10(-9)cm(3)?s(-1) at 540 K.     

Electron-catalyzed mutual neutralization of various anions with Ar+: evidence of a new plasma process

The mutual neutralization of anions with Ar+ has been studied by variable electron and neutral density attachment mass spectrometry. Evidence of a previously unobserved plasma loss process, electron-catalyzed mutual neutralization (ECMN), e.g., SF6-+Ar+ + e-→neutrals + e-, is reported. Results for 10 species suggest that ECMN occurs generally and significantly affects the total ion-loss rate in plasmas with electron densities exceeding 10(10) cm-3. ECMN is discussed in the context of other known three-body plasma processes, the mechanisms for which appear insufficient to explain the observed effect. A mechanism for ECMN involving an incident electron facilitating energy transfer to the internal modes of the anion is proposed.