The electron density ne of stationary plasma can be easily obtained on the basis of the resonance frequency f of a curling probe (CP) measured by a network analyzer (NWA). However, in pulsed plasma with discharge period T, the ne and f values periodically change with time. This study extends the conventional CP technique to a time-resolved measurement of the pulse-modulated electron density. The condition necessary for the measurement is revealed to be synchronization of NWA with the pulse modulation, which is expressed as (n − 1)T/TSWP = integer (1, 2, …) for a number n of data point and sweep time TSWP.

A plasma-induced shift in the resonance frequency of a curling probe measured by using a network analyzer (NWA) yields the electron density. This technique was applied here for measuring time-varying electron density in pulsed DC glow discharges. Using the NWA in an on-sweep synchronization mode with the discharge pulse allows measuring at pulse frequencies below 0.5 kHz. For higher pulse frequencies, an on-point mode was introduced which enabled time-resolved measurements of electron density at pulse frequencies reaching 25 kHz, with the minimal time interval of 2 µs, typically for nitrogen discharge at 10 Pa. In the afterglow regime, the decay time constant of electron density was measured for nitrogen and argon discharges at 40 Pa. In the case of argon, the electron density was observed to decrease in three steps. This characteristic behavior was tentatively attributed to a bi-Maxwellian electron energy distribution and Ramsauer effect, supported by Langmuir probe measurements.

Our objective was simply to report a sedge species, Carex kobomugi Ohwi that has beneficial bacterial associations under low Fe and P conditions of the Hasaki coast, Japan. C. kobomugi is the dominant species in our study area and grows closest to the sea. C. kobomugi showed higher Fe and P content, while these nutrients were less available under alkaline root-zone soil. Within the roots, mycorrhizal fungal colonization was absent, and endophytic fungal colonization was low. On the contrary, endophytic bacteria (e.g. Bacillus sp., Streptomyces luteogriseus, and Pseudomonas fluorescens) were isolated, which exhibited both siderophore production and inorganic phosphate solubilization under Fe or P limited conditions. Our results suggest that colonization of root tissue by these bacteria contribute to the Fe and P uptakes by C. kobomugi by increasing availability in the soil.

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Relationships among Curie point, spontaneous polarization, lattice parameters with consideration of spontaneous strain and piezoelectric charge coefficient were calculated as functions of two-dimensional stress in c-axis-oriented PbTiO3 thin films using a modified Devonshire form of the elastic Gibbs free energy. A compressive stress of approximately 500 MPa was predicted by a finite-element method analysis of the PbTiO3/Pt/Ti/SiO2/Si structure. A 90° C shift in the Curie point was estimated from the compressive stress, and shifts of other properties were accompanied with a shift of phase transition.