This study aims to investigate the spatiotemporal variation, chemical composition, and source apportionment of marine fine particles (PM2.5) as well as their regional transport toward the Matsu Islands located near the coastline of northwestern Taiwan Strait. Four offshore island sites located at the Matsu Islands were selected to conduct both regular and intensive sampling of marine PM2.5. Water-soluble ionic species, metallic elements, and carbonaceous contents were then analyzed to characterize the chemical characteristics of marine PM2.5. In order to identify the potential sources and their contributions to marine PM2.5, chemical mass balance (CMB) receptor model was employed along with the backward trajectory simulation to resolve the source apportionment of marine PM2.5 and to explore their transport routes in different seasons. The results showed that high PM2.5 concentrations were commonly observed during the northeastern monsoon periods. Additionally, marine PM2.5 concentration decreased from the west to the east with the highest PM2.5 at the Nankang Island and the lowest PM2.5 at the Donyin Island in all seasons, indicating an obvious concentration gradient of PM2.5 transported from the continental areas to the offshore islands. In terms of chemical characteristics of PM2.5, the most abundant water-soluble ions of PM2.5 were secondary inorganic aerosols (SO42−, NO3−, and NH4+) which accounted for 55–81% of water-soluble ions and 29–52% of marine PM2.5. The neutralization ratios of PM2.5 were always less than unity, indicating that NH4+ cannot solely neutralize nss-SO42+ and NO3− in marine PM2.5 at the Matsu Islands. Although crustal elements (Al, Ca, Fe, K, and Mg) dominated the metallic content of marine PM2.5, trace anthropogenic metals (Cd, As, Ni, and Cr) increased significantly during the northeastern monsoon periods, particularly in winter. Organic carbons (OCs) were always higher than elemental carbons (ECs), and the mass ratios of OC and EC were generally higher than 2.2 in all seasons, implying that PM2.5 was likely to be aged particles. During the poor air quality periods, major air mass transport routes were the northern transport and the anti-cyclonic circulation routes. Source apportionment results indicated that fugitive soil dusts and secondary aerosols were the major sources of marine PM2.5 at the Matsu Islands, while, in winter, biomass burning contributed up to 15% of marine PM2.5. This study revealed that cross-boundary transport accounted for 66~84% of PM2.5 at the Matsu Islands, suggesting that marine PM2.5 at the Matsu Islands has been highly influenced by anthropogenic emissions from neighboring Fuzhou City as well as long-range transport from Northeast Asia.

This study uses radio-frequency sputtering methods to deposit lead titanate thin films with different contents of Ca on Pt∕Ti∕SiO2∕Si substrates to form Pb1−xCaxTiO3 (PCT) thin films. The PCT thin films contained different amounts of Ca in order to examine the influence of the Ca content on the properties of thin films. Analysis of the electrical properties of the PCT thin films revealed that their relative permittivities, dissipation factors, and pyroelectric coefficients tend to increase with the Ca content. On the other hand, the coercive field and remnant polarization decreased with an increase in the Ca content. In addition, the measured data indicated that the figure of merit for voltage (Fv) and the figure of merit for detectivity (FD) of a PCT (30) thin film are the highest with values of 0.033m2C−1 and 0.862×10−6(m3J−1)1∕2, respectively. Therefore, the PCT (30) thin film was evaluated as the best composition for manufacturing pyroelectric infrared (PIR) sensors. PCT thin films were also used to fabricate thermal PIR sensors by surface machining technology. The detectivity measurement showed that the PIR sensor with PCT (30) thin films has the highest value of D* (1.29×107cmHz1∕2∕W) at 0.3Hz.

Growth and dielectric behavior of radio frequency magnetron-sputtered lead magnesium niobate thin films Electrical and pyroelectric properties of in-plane polarized lead lanthanum titanate thin film Appl. Phys. Lett. 79, 668 (2001); 10.1063/1.1387265Fabrication of excess PbO-doped Pb(Zr 0.52 Ti 0.48 ) O 3 thin films using radio frequency magnetron sputtering method J.Lead-zirconate-titanate ͓Pb͑Zr 52 Ti 48 ͒O 3 ,PZT͔ thin films, 0.5 m thick, were deposited onto Pt/Si substrate at room temperature using the radio frequency planar magnetron sputtering technique. A perovskite structure in the PZT thin film was obtained after the annealing processes. The annealing temperature varied from 650 to 750°C in this experiment to find the optimized annealing temperature. Using x-ray diffraction analysis, the lowest full width of the half maximum ͑110͒ plane was 0.23°for the sample at 650°C annealing temperature. The values of the remanent polarization Pr and coercive field E c of the PZT thin film were 100 nC cm Ϫ2 and 0.6 kV cm Ϫ1 , respectively, at 60 Hz. The measured pyroelectric coefficient in 0.5 m thin films was 3.12ϫ10 Ϫ4 C/m 2 K at 50°C. Their dielectric constant and loss tangent were 494 and 0.072, respectively, at 1 kHz. The surface structure of the PZT thin film was examined using scanning electron microscopy and the grain size was in the range of 0.08-0.14 m.

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