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This paper reports on a method for the investigation of mechanical stress on MEMS sensor and actuator structures due to packaging
processes. A silicon test chip is developed and manufactured to validate the simulation results. Finite element analysis (FEA)
is used to optimize the geometric parameters and to find a stress sensitive sensor geometry. A diaphragm structure is used
as mechanical amplifier for bulk induced stresses during the packaging process. Piezo resistive solid state resistors are
doped into the surface of the chip to measure the stress in the diaphragms and at the contact pads being most significant
locations for analysis. A high precision ohmmeter was used to measure the resistance prior and past the packaging process.
The captured data allows for computation of the resulting stress loads in magnitude. Therefore, a stress evaluation of different
packaging technologies is conducted and the impact of the packaging process on reliability can be estimated immediately. 相似文献
4.
Characterization of emissions from burning incense 总被引:3,自引:0,他引:3
The primary objective of this study was to improve the characterization of particulate matter emissions from burning incense. Emissions of particulate matter were measured for 23 different types of incense using a cyclone/filter method. Emission rates for PM2.5 (particulate matter less than 2.5 microm in aerodynamic diameter) ranged from 7 to 202 mg/h, and PM2.5 emission factors ranged from 5 to 56 mg/g of incense burned. Emission rates were also determined using an electrical low pressure impactor (ELPI) and a small electrostatic precipitator (ESP), and emission rates were compared to those determined using the cyclone/filter method. Emission rates determined by the ELPI method were consistently lower than those determined by the cyclone/filter method, and a linear regression correlation was found between emission rates determined by the two methods. Emission rates determined by the ESP method were consistently higher than those determined by the cyclone/filter method, indicating that the ESP may be a more effective method for measuring semivolatile particle emissions. A linear regression correlation was also found between emission rates determined by the ESP and cyclone/filter methods. Particle size distributions were measured with the ELPI, and distributions were found to be similar for most types of incense that were tested. Size distributions by mass typically ranged from approximately 0.06 to 2.5 microm in aerodynamic diameter, with peak values between 0.26 and 0.65 microm. Results indicated that burning incense emits fine particulate matter in large quantities compared to other indoor sources. An indoor air quality model showed that indoor concentrations of PM25 can far exceed the outdoor concentrations specified by the US EPA's National Ambient Air Quality Standards (NAAQS), so incense smoke can pose a health risk to people due to inhalation exposure of particulate matter. Emissions of carbon monoxide (CO), nitric oxide (NO), and sulfur dioxide (SO2) were also measured for seven types of incense. Emission rates of the gaseous pollutants were sufficient to cause indoor concentrations, estimated using the indoor air quality model, to exceed the outdoor concentrations specified by the NAAQS under certain conditions. However, the incense samples that were tested would fill a room with thick smoke under these conditions. 相似文献
5.
Pawel E. Malinowski Atsushi Nakamura Dimitri Janssen Yoshitaka Kamochi Ichiro Koyama Yu Iwai Anna Stefaniuk Ewelina Wilenska Caterin Salas Redondo David Cheyns Soeren Steudel Paul Heremans 《Organic Electronics》2014,15(10):2355-2359
We report on the fabrication of organic photodetectors (OPD) based on isolated islands of P3HT:PCBM. Pattern transfer to the active material was done with photolithography based on non-fluorinated solvents and the excessive organic semiconductor was removed with oxygen plasma reactive ion etching. The photoresist system used was found to be benign to the P3HT:PCBM layer as confirmed by absorption, thickness and roughness measurements. Current–voltage characteristics and external quantum efficiency (EQE) remained unchanged after the patterning process. It was demonstrated that it is possible to photolithographically pattern isolated islands with 200 μm edge length with the same dark current density (<10−5 A/cm2 at −2 V bias voltage) and photocurrent density (>5 × 10−3 A/cm2 at −2 V). Furthermore, concerning the solar cell performance, the patterned, small-area devices showed power conversion efficiency of 2.1% and fill-factor of 60%. Dark current was observed to depend on the size of the remaining semiconductor island, which was demonstrated on OPDs with diameter of 50 μm. The presented results show the feasibility of fabrication of isolated devices based on organic semiconductors patterned with non-fluorinated photolithography. 相似文献
6.
Steven C. Patch Margaret C. Ullman James J. Jetter 《The Science of the total environment》2009,407(22):5818-5824
A controlled simulation experiment was performed to assess whether dislodgeable arsenic can be tracked onto carpets via foot traffic from chromated copper arsenate (CCA) pressure-treated decks. The pilot simulation study demonstrated that it is possible to track arsenic from CCA-decks onto carpets under the test conditions evaluated. A total of nine CCA-decks and two non-CCA-treated control surfaces were tested under wet and dry conditions. Five participants walked in a controlled manner (60 cycles, 11 steps per cycle) across decks and then walked over various lanes of carpet to simulate the tracking of arsenic indoors on the bottoms of shoes under heavy foot traffic conditions. To determine if arsenic was transferred from the CCA-treated wood to the carpet via shoes, laboratory analysis was performed on three different types of samples: (1) wipe samples of dislodgeable arsenic from a 46 cm2 area of carpet, (2) dust samples obtained from vacuuming a 7442 cm2 area of carpet, and (3) extractions of 13 cm2 carpet samples. Wipe samples were also taken directly from the deck lumber. Following digestion and extraction, the amount of arsenic in each sample was measured using Graphite Furnace Atomic Absorption Spectrometry. The mean arsenic concentration measured on the carpets was 2.52 μg/(100 cm2) and 2.05 μg/(100 cm2) with wipes for the dry and wet conditions, respectively, 4.69 μg/(100 cm2) and 0.68 μg/(100 cm2) with vacuumed dust for the dry and wet conditions, respectively, and 15.56 μg/(100 cm2) and 12.31 μg/(100 cm2) with carpet extractions for the dry and wet conditions, respectively. The mean arsenic concentration measured on the decks was 22.2 μg/(100 cm2) with wipes. Further research is needed to determine if indoor exposure to arsenic due to track-in from outdoor decks via foot traffic is significant compared to exposures from other sources. 相似文献
7.
Cordtz J Olde B Solem K Ladefoged SD 《Hemodialysis international. International Symposium on Home Hemodialysis》2008,12(3):369-377
Intradialytic hypotension (IDH) is one of the most important short-term complications to hemodialysis (HD). Inadequate cardiac filling due to a reduction in the central blood volume is believed to be a major etiological factor. The aim of this study was to evaluate whether these pathophysiologic events are reflected in the central venous oxygen saturation (ScO(2)) and thoracic admittance (TA) during dialysis. Twenty ambulatory HD patients, 11 hypotension prone (HP) and 9 hypotension resistant, with central vascular access, were monitored during 3 HD sessions each. ScO(2), TA, finger blood pressure (BP), and relative change in blood volume (DeltaBV) were measured and sampled continuously. The relative TA decrease and DeltaBV were both largest in the HP group (p<0.05 for both), whereas ScO(2) decreased only in HP patients (p<0.001). Baseline TA was lower in the HP group (p<0.01). Changes in ScO(2) and TA correlated much closer than did changes in ScO(2) and DeltaBV (r=0.43 and 0.18, respectively). Our results suggest that an intradialytic decrease in cardiac output, as reflected by a fall in ScO(2), is a common feature to HD patients prone to IDH. In patients using a central vascular access, ScO(2) and TA measurements may be more specific to the pathophysiologic events preceding IDH than DeltaBV-the current standard monitoring method. 相似文献
8.
A governing equation was developed to predict the density ρ(org) of organic material composed of carbon, oxygen, and hydrogen using the elemental ratios O:C and H:C as input parameters: ρ(org) = 1000 [(12 + 1(H:C) + 16(O:C)]/[7.0 + 5.0(H:C) + 4.15(O:C)] valid for 750 < ρ(org) < 1900 kg m(-3). Comparison of the actual to predicted ρ(org) values shows that the developed equation has an accuracy of 12% for more than 90% of the 31 atmospherically relevant compounds used in the training set. The equation was further validated for secondary organic material (SOM) produced by isoprene photo-oxidation and by α-pinene ozonolysis. Depending on the conditions of SOM production, ρ(org/SOM) ranged from 1230 to 1460 kg m(-3), O:C ranged from 0.38 to 0.72, and H:C ranged from 1.40 to 1.86. Atmospheric chemistry models that simulate particle production and growth can employ the developed equation to simulate particle physical properties. The equation can also extend atmospheric measurements presented as van Krevelen diagrams to include estimates of the material density of particles and their components. Use of the equation, however, is restricted to particle components having negligible quantities of additional elements, most notably nitrogen. 相似文献
9.
Soeren Schumacher Thomas Nagel Frieder W. Scheller Nenad Gajovic-Eichelmann 《Electrochimica acta》2011,(19):6607
In addition to the well-established spectroscopic Alizarin Red S (ARS) assay for the determination of binding constants between arylboronic acids and different saccharides, we report the use of ARS as a reporter in an electrochemical set-up. The electrochemical properties of ARS, the binding to phenyl boronic acid (PBA) and the competition with fructose in phosphate buffer at pH 7.4 were investigated by cyclic voltammetry (CV). By choosing a negative scan direction (starting at +0.2 V), a quasi-reversible process was detected at E0′ = −0.59V with ΔEp = 0.1V. An irreversible oxidation peak at +0.42 V could also be detected. These peaks are characterised both as a 2-proton-2-electron transfer and corresponds to the oxidation and reduction of the anthraquinone or the ortho-quinone moiety. After addition of phenylboronic acid a new oxidation peaks occurred at −0.42 V which correlates with the ARS–PBA interaction. The peak current increased with increasing phenylboronic acid concentration according to the release of BA and formation of the ARS–PBA ester. After addition of fructose the peak current decreases again, in proportion to the fructose concentration, enabling the use of ARS as an electrochemical reporter for fructose detection up to 50 mM. Also the interaction with other cis-diol containing compounds such as sorbitol, mannitol, glucose and mannose was investigated and a dependence based on already published binding constants to phenylboronic acid could be shown. 相似文献
10.
Erkka Saukko Soeren Zorn Mikinori Kuwata Jorma Keskinen Annele Virtanen 《Aerosol science and technology》2013,47(7):531-537
The phase state of secondary organic aerosol (SOA) has an impact on its lifetime, composition, and its interaction with water. To better understand the effect of phase state of SOA on climate interactions, we studied the SOA phase state and the effect of its history and report here the phase state and the humidity-induced phase hysteresis of multicomponent-seeded SOA particles produced in a large, continuously stirred tank reactor. We determined the phase state of the particles by their bounced fraction impacting on a smooth substrate in a low-pressure impactor. The particles were composed of ammonium sulfate ([NH4]2SO4) seed and a secondary organic matter (SOM) shell formed from oxidized α-pinene or isoprene. The ammonium sulfate (AS) seed dominated the deliquescence of the α-pinene SOM multicomponent particles, whereas their efflorescence was strongly attenuated by the SOM coating. Particles coated with isoprene SOM showed continuous phase transitions with a lesser effect by the AS seed. The results agree with and independently corroborate contemporary research.Copyright 2015 American Association for Aerosol Research 相似文献