86 research outputs found
COMPARISON OF EMG ACTIVITY WITH DYNAMIC MOVEMENT AND STATIC POSTURE ON VIBRATION PLATFORM
The aim of this study is to investigate the difference among dynamic movement and static posture on vibration platform as well as no vibration. For this purpose, six healthy male subjects were recruited in this study. Each subject was instructed to maintain four situations: dynamic movement with vibration (frequency: 40 Hz, amplitude: 1 mm), and no-vibration; static posture with vibration (frequency: 40 Hz, amplitude: 1 mm), and novibration.
Result showed statistically significant increase at EMG rms of whole body vibration treatment and EMG rms value of dynamic movement was significantly larger than that of static posture (
ACCELERATION ON DIFFERENT BODY POSITIONS DURING RUNNING ON A TREADMILL
Many fitness index used V˙O2max and heart rate to estimate energy expenditure, but these current methods require expensive equipment for the direct measurement. This study tried to determine a more convenient way to estimate energy expenditure by comparing the relationship of heart rate with acceleration on different positions while running on a treadmill. Eight males (23-32 yr) wore three tri-axial accelerometers, and the placements of accelerometers were left wrist, trunk (low back) and left ankle. Each participant walked for 30 sec at 4 and 6 km·h-1, ran 30 sec at 8, 10, 12, 14, 16 km·h-1 after they keep stable heart rate in these speeds. All the total accelerations on three placements are significantly correlated with heart rate in this study which indicated that accelerations on human body is a good way to estimate energy expenditure. This information is very useful to develop a new device to accurately estimate energy expenditure using watch which is more convenient compare to current devices in the market
Clinical features and outcome of sporadic serogroup W135 disease Taiwan
BACKGROUND: Few published reports have evaluated the clinical features and outcome of serogroup W135 meningococcal disease. In Taiwan, W135 is the second most prevalent meningococcal disease serogroup. METHOD: A nationwide study was conducted to retrospectively analyze epidemiologic data from 115 patients with laboratory confirmed meningococcal disease that occurred from 2001 through 2003. RESULTS: Serogroup W135 accounted for 26% of all cases and most (76.7%) were older than 20 years. There were no cases of serogroup W135 meningococcal disease associated with Hajj pilgrims, and all cases were sporadic. In 88 patients with complete case records, we compared the presenting symptoms, signs, laboratory data, and outcomes between W135 and non-W135 patients. There were no differences in presenting symptoms except for the higher prevalence of pneumonia found in W135 patients (23.8% vs. 1.5%; OR: 20.6; 95%CI: 2.3–189.0; p = 0.003). The distribution of inflammatory cells in CSF in patients with meningitis was also different between W135 and non-W135 patients. W135 patients had a trend toward more intubations and shock but it did not achieve statistical significance. In multivariate analysis of factors associated with death, three independent factors were found: bacteremia without meningitis, altered mental status, and petechiae or purpura on admission. CONCLUSION: Sporadic serogroup W135 meningococcal disease is an important component of the meningococcal disease burden in Taiwan, but it is not directly associated with Hajj pilgrims. Compared with patients infected by other serogroups of meningococci, patients with serogroup W135 were older and more likely to have extrameningeal involvement such as pneumonia
Fabrication and Characterization of High-Sensitivity Underwater Acoustic Multimedia Communication Devices with Thick Composite PZT Films
This paper presents a high-sensitivity hydrophone fabricated with a Microelectromechanical Systems (MEMS) process using epitaxial thin films grown on silicon wafers. The evaluated resonant frequency was calculated through finite-element analysis (FEA). The hydrophone was designed, fabricated, and characterized by different measurements performed in a water tank, by using a pulsed sound technique with a sensitivity of −190 dB ± 2 dB for frequencies in the range 50–500 Hz. These results indicate the high-performance miniaturized acoustic devices, which can impact a variety of technological applications
Fabrication and Characterization of High-Sensitivity Underwater Acoustic Multimedia Communication Devices with Thick Composite PZT Films
This paper presents a high-sensitivity hydrophone fabricated with a Microelectromechanical Systems (MEMS) process using epitaxial thin films grown on silicon wafers. The evaluated resonant frequency was calculated through finite-element analysis (FEA). The hydrophone was designed, fabricated, and characterized by different measurements performed in a water tank, by using a pulsed sound technique with a sensitivity of −190 dB ± 2 dB for frequencies in the range 50-500 Hz. These results indicate the high-performance miniaturized acoustic devices, which can impact a variety of technological applications
Investigation of Low-Cost Surface Processing Techniques for Large-Size Multicrystalline Silicon Solar Cells
The subject of the present work is to develop a simple and effective method of enhancing conversion efficiency in large-size solar cells using multicrystalline silicon (mc-Si) wafer. In this work, industrial-type mc-Si solar cells with area of 125×125 mm2 were acid etched to produce simultaneously POCl3 emitters and silicon nitride deposition by plasma-enhanced chemical vapor deposited (PECVD). The study of surface morphology and reflectivity of different mc-Si etched surfaces has also been discussed in this research. Using our optimal acid etching solution ratio, we are able to fabricate mc-Si solar cells of 16.34% conversion efficiency with double layers silicon nitride (Si3N4) coating. From our experiment, we find that depositing double layers silicon nitride coating on mc-Si solar cells can get the optimal performance parameters. Open circuit (Voc) is 616 mV, short circuit current (Jsc) is 34.1 mA/cm2, and minority carrier diffusion length is 474.16 μm. The isotropic texturing and silicon nitride layers coating approach contribute to lowering cost and achieving high efficiency in mass production
Efficiency Improved by H
The photovoltaic (PV) effects have been investigated and improved using efficient treatments both on single-crystalline (sc) and on multicrystalline (mc) silicon (Si) solar cells. The major effect of forming gas (FG) treatment on solar cell performance is the fill-factor values, which increase 3.75% and 8.28%, respectively, on sc-Si and mc-Si solar cells. As for the optimal 15%-H2 ratio and 40-minute FG treatment, the conversion efficiency (η) values drastically increase to 14.89% and 14.31%, respectively, for sc- and mc-Si solar cells. Moreover, we can measure the internal quantum efficiency (IQE) values increase with H2-FG treatment under visible wavelength (400~900 nm) radiation. Thus based on the work in this research, we confirm that H2 passivation has become crucial both in PV as well as in microelectronics fields. Moreover, the developed mc-Si solar cell by proper H2 FG treatment is quite suitable for commercial applications
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