Measurement of the nitrogen(+) ((5)sulfide) state radiative lifetime

The radiative lifetime of metastable N{dollar}\sp{+}{dollar}(2s2p{dollar}\sp3{dollar} {dollar}\sp5{dollar}S{dollar}\sb2{dollar}) has been measured by directly monitoring the spontaneous emission from stored N{dollar}\sp{+}{dollar} in a radio-frequency ion trap. The electron excitation technique was used to create N{dollar}\sp{+}{dollar}({dollar}\sp5{dollar}S{dollar}\sb2{dollar}), and the spontaneous emission decay curve via spin-forbidden electric dipole transitions from 2s2p{dollar}\sp3{dollar} {dollar}\sp5{dollar}S{dollar}\sb2{dollar} to 2s{dollar}\sp2{dollar}2p{dollar}\sp2{dollar} {dollar}\sp3{dollar}P{dollar}\sb{1,2}{dollar} ground state at 2139.68 and 2143.55 A were observed. A measured value for the {dollar}\sp5{dollar}S{dollar}\sb2{dollar} radiative lifetime is {dollar}\tau\sb{\rm rad}{dollar} = 6.4 {dollar}\pm{dollar} 0.7 ms which is in good agreement with the theoretical result by Hibbert and Bates but longer than the measurement by Knight (4.2 {dollar}\pm{dollar} 0.6 ms). A careful study of non-radiative quenching and ion loss due to charge transfer of the metastable state was made. It was found that Knight\u27s results were non-reproducible at a higher vacuum system with a meshed wall ion trap. This is perhaps due to unknown impurity gases in Knight\u27s vacuum system. This measurement will clarify the discrepancy between Knight\u27s measurement and theoretical calculations. An accurate value for the lifetime of the metastable N{dollar}\sp{+}{dollar}(2s2p{dollar}\sp3{dollar} {dollar}\sp5{dollar}S{dollar}\sb2{dollar}) ion is important in interpretation of the UV spectra of aurora

Energy flow in nonlinear circuits

Apparent power and reactive power are two critical quantities in energy flow studies in electrical power systems. Existing definitions for these terms work well when both voltages and currents are sinusoidal with respect to time. However, both apparent and reactive power have no physical meaning. When these physically unclarified quantities are applied to non-sinusoidal systems, the following questions related to power flow remain not fully answered to date. What do these quantities really mean? Is it fair to bill customers based on the measurement of physically not meaningful quantities? What is the efficient way, both economical and technical, to compensate non-active power in power networks?;To answer the above mentioned questions, this thesis analyzes energy flow in nonlinear circuits, clarifies and proposes new power quantities with physical interpretations that are practical and effective when voltages and/or currents are non-sinusoidal. The suggested definitions are measurable quantities based on time-domain approach, and are useful in evaluating the power quality and efficiency in electrical systems. The measurement method and compensation with active filters are also discussed

Pickering emulsions responsive to CO₂/N₂ and light dual stimuli at ambient temperature

A dual stimulus-responsive n-octane-in-water Pickering emulsion with CO₂/N₂ and light triggers is prepared using negatively charged silica nanoparticles in combination with a trace amount of dual switchable surfactant, 4-butyl-4-(4-N,N-dimethylbutoxyamine) azobenzene bicarbonate (AZO-B₄) as stabilizers. On one hand, the emulsion can be transformed between stable and unstable at ambient temperature rapidly via the N₂/CO₂ trigger, and on the other hand a change in droplet size of the emulsion can occur upon light irradiation/re-homogenization cycles without changing the particle/surfactant concentration. The dual responsiveness thus allows for a precise control of emulsion properties. Compared with emulsions stabilised by specially synthesized stimuli-responsive particles or by stimuli-responsive surfactants, the method reported here is much easier and requires relatively low concentration of surfactant (≈1/10 cmc), which is important for potential applications

Smart worm-like micelles responsive to CO₂/N₂ and light dual stimuli

CO₂/N₂ and light dual stimuli-reponsive worm-like micelles (WLMs) were obtained by addition of a relatively small amount of a switchable surfactant, 4-butyl-4´-(4-N,N-dimethylhexyloxy-amine) azobenzene bicarbonate (AZO-B6-CO₂), sensitive to the same triggers into a binary aqueous solution of cetyltrimethyl ammonium bromide (CTAB) and sodium salycilate (NaSal)

Low Acceleration Overload Catapult Technique for Throwing the Small Scout Robot

The small scout robot is generally thrown into the war zone by soldier. The short thrown distance and the danger of soldier exposed to the enemy limit the application of the small scout robot. So this paper presents a type of low acceleration overload catapult device of no flash, no smoke and no sound. It can throw the small scout robot covertly to long distances with low acceleration overload, and avoid the danger that soldier be exposed to the enemy when artificial throwing. The high and low pressure chambers of the catapult device achieve the low acceleration overload launching, and eliminate the risk of robot damaged by huge acceleration overload. The covert launching of no flash, no smoke and no sound is achieved by the piston to seal the gun propellant gas in barrel. Based on the interior ballistic model, the interior ballistic performance is calculated. The experiment for measuring the acceleration overload of the projectile is achieved by using the catapult device prototype and the measurement system developed by authors. The simulation and test results show that this catapult device can meet the requirement to throw the small scout robot into the war zone