[en] We have developed a piezoelectric microvalve with a silicon seat for the propulsion system of a micro-satellite. The silicon seat is fabricated with narrow sealing rings to reduce internal leaks. The fatigue performance of the silicon seat is characterized. The lifetime of the silicon seat without coating is approximately 25 000 times, which cannot meet the requirement for astronautic applications. To improve its fatigue performance, the silicon seat is deposited with Cu and parylene, respectively. The two seats both meet the sealing requirement after 10"5 cycle operation. Several rings of the seats deposited with Cu fractured after the fatigue tests, whereas none of the rings of the seats deposited with parylene fractured due to the obvious reduction of the impact stress. (paper)

[en] We estimated the short-term effects of particulate matter (PM) pollution with aerodynamic diameters ≤2.5 μm (PM_2.5) and between 2.5 and 10 μm (PM_c) on hospital outpatient visits due to overall and specific respiratory diseases, as well as the associated morbidity burden in Dongguan, a subtropical city in South China. A time-series model with quasi-Poisson link was used to examine the association between PM pollution and morbidities from respiratory diseases, COPD, asthma and pneumonia in Dongguan during 2013–2015. We further estimated the morbidity burden (population attributable fraction and attributable morbidity) due to ambient PM pollution. A total of 44,801 hospital outpatient visits for respiratory diseases were recorded during the study period. Both PM_2.5 and PM_c were found to be significantly associated with morbidity of overall respiratory diseases, COPD, and asthma. An IQR (interquartile range) increase in PM_2.5 at lag₀₃ day was associated with 15.41% (95% CI: 10.99%, 20.01%) increase in respiratory morbidity, and each IQR increase in PM_c at lag₀₃ corresponded to 7.24% (95% CI: 4.25%, 10.32%) increase in respiratory morbidity. We did not find significant effects of PM_2.5 and PM_c on pneumonia. Using WHO's guideline (25 μg/m³) as reference concentration, about 8.32% (95% CI: 5.90%, 10.86%) of respiratory morbidity (3727, 95% CI: 2642, 4867, in morbidity number) were estimated to be attributed to PM_2.5, and 0.86% (95% CI: 0.50%, 1.23%) of respiratory morbidity, representing 385 (95% CI: 225, 551) hospital outpatient visits, could be attributed to coarse particulate pollutant. Our study suggests that both fine and coarse particulate pollutants are an important trigger of hospital outpatient visits for respiratory diseases, and account for substantial respiratory morbidity in Dongguan, China. - Highlights: • We estimated respiratory morbidity burden due to fine and coarse PM pollutants. • Both PM_2.5 and than coarse PM pollutants were associated with respiratory morbidity. • Substantial morbidity burden can be attributable to fine and coarse particles. - Both fine and coarse particulate matter pollutants were found to be associated with increased respiratory morbidity, particularly from COPD and asthma. Substantial respiratory morbidity burden could be attributable to these two pollutants in Dongguan, China.

[en] Highlights: • This study examines the acute health effects of CO pollution. • Exposure to ambient CO was associated with increased risk of respiratory diseases. • Female and the elderly appeared higher risk of respiratory outpatient visits. -- Abstract: The toxicity of high-concentration carbon monoxide (CO) on human health has previously been documented. However, the epidemiological evidence on the association between acute exposure to ambient CO and respiratory diseases is relatively lacking and controversial.