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81.
Highly c-axis oriented AlN films, 3.15 μm thick, were grown by rf reactive sputtering technique at 200 °C on bare and Pt-covered Si(100) substrates previously oxidized to a thickness of about 2 μm in wet oxygen atmosphere. A Pt film, 2200 Å thick, was then sputtered on the free surface of the AlN/Pt/SiO2/Si multilayer at 200 °C without breaking the vacuum in order to avoid any oxidation effects of the layers. The multilayers were then annealed in air at 900 °C for different time lengths up to 32 h in order to test the materials' resistivity to harsh environment. The influence of this high temperature annealing (HTA) on the thin films' crystallinity, as well as on the c-AlN piezoelectricity and Pt sheet resistivity was investigated at room temperature before and after each annealing. X ray diffraction investigations revealed that the films' crystallinity was improved by the HTA: the full width of half maximum of the AlN(002) and Pt(111) peaks decreases from 0.39° to 0.24°, and from 0.42° to 0.28° after 32-hours-HTA. Scanning electron microscopy, four points probe and piezoelectricity tests revealed that the morphology and the sheet resistivity (in the range from 0.6 to 0.5 Ω/sq) of the outer Pt film, as well as the AlN piezoelectric constants d33 (in the range from 6.2 to 7.4⋅10−12 C/N) was quite unaffected by the HTA even after 32 h of annealing. 相似文献
82.
M. Faqir G. Verzellesi F. Fantini F. Danesin F. Rampazzo G. Meneghesso E. Zanoni A. Cavallini A. Castaldini N. Labat A. Touboul C. Dua 《Microelectronics Reliability》2007,47(9-11):1639
Traps are characterized in AlGaN–GaN HEMTs by means of DLTS techniques and the associated charge/discharge behavior is interpreted with the aid of numerical device simulations. Under specific bias conditions, buffer traps can produce “false” surface-trap signals, i.e. the same type of current-mode DLTS (I-DLTS) or ICTS signals that are generally attributed to surface traps. Clarifying this aspect is important for both reliability testing and device optimization, as it can lead to erroneous identification of the degradation mechanism, thus resulting in wrong correction actions on the technological process. 相似文献
83.
G Cavallini A Tittobello L Frulloni E Masci A Mariana V Di Francesco 《Canadian Metallurgical Quarterly》1996,335(13):919-923
BACKGROUND: Endoscopic retrograde cholangiopancreatography (ERCP) is associated with elevated levels of pancreatic enzymes and pancreatitis. Gabexate, a protease inhibitor, has been used to prevent pancreatic damage related to ERCP. METHODS: We conducted a multicenter, double-blind comparison of gabexate (1 g given by intravenous infusion starting 30 to 90 minutes before endoscopy and continuing for 12 hours afterward) with placebo (mannitol and sodium chloride, administered in the same fashion). A total of 435 adults scheduled to undergo ERCP and, when indicated, endoscopic sphincterotomy underwent randomization; 17 were excluded from the final analysis for various reasons. The remaining 418 patients (mean age, 60.4 years)--208 in the gabexate group and 210 in the placebo group--were analyzed. Acute pancreatitis was considered to be present if serum amylase or lipase levels (or both) were five times greater than the upper limits of normal in association with the onset of pancreatic pain. RESULTS: After the procedures, 276 patients (66 percent) had elevated pancreatic-enzyme levels; the frequency was similar in the two groups. Mean serum amylase values were higher in the placebo group than in the gabexate group through 24 hours of observation (P=0.03). Twelve patients in the gabexate group and 29 in the placebo group had abdominal pain (6 percent vs. 14 percent, P=0.009). Sixteen patients in the placebo group and five in the gabexate group had acute pancreatitis (8 percent vs. 2 percent, P=0.03). Two patients treated with gabexate and six given placebo had adverse events, all of which resolved. Two patients given placebo died of acute pancreatitis; one was excluded from the evaluation because pancreatitis was present before endoscopy. One patient in the gabexate group died, from a myocardial infarction. CONCLUSION: Prophylactic treatment with gabexate reduced pancreatic damage related to ERCP, as reflected by reductions in the extent but not the frequency of elevated enzyme levels and in the frequency of pancreatic pain and acute pancreatitis. 相似文献
84.
85.
Fabrizio Bezzo Francesco Micheletti Riccardo Muradore Massimiliano Barolo 《Journal of Process Control》2005,15(8):1609-930
The use of model predictive control (MPC) in middle-vessel continuous distillation column (MVCC) is discussed. It is shown that using a 5 × 5 MPC implementation (where all levels are included in MPC as integral process variables) allows using a smaller middle-vessel, particularly when disturbances can be measured: a good performance is ensured without having the middle vessel drained or overfilled. Also, it is shown that MPC practically circumvents the issue of tuning the middle-vessel level controller. Furthermore, the MVCC design makes conventional decentralised control perform comparably to MPC. 相似文献
86.
Rosso Ilaria Antonini Massimiliano Galletti Camilla Saracco Guido Specchia Vito 《Topics in Catalysis》2004,30(1-4):475-480
Topics in Catalysis - Ru-based catalysts supported on A zeolites and alumina were synthesised, characterised (XRD, SEM-EDS, TPR) and tested under realistic conditions for the preferential oxidation... 相似文献
87.
Daniele Quaratino Massimiliano Fenice Federico Federici Alessandro D'Annibale 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2006,81(6):832-840
This study reports the statistical optimisation through response surface methodology of the growth medium for Panus tigrinus manganese‐dependent peroxidase (MnP) production in shaken culture. Three crucial variables, including carbon source, malonic acid and Mn2+, were optimised in a nitrogen‐limited medium. Sucrose was the best carbon source for MnP production. Mn2+ ions and malonic acid significantly stimulated MnP production at an optimal concentration of 53 mg dm?3 and 8.2 mmol dm?3, respectively, resulting in 0.83 U cm?3. Further experiments were performed in lab‐scale stirred tank (STR) and bubble‐column (BCR) reactors using the previously optimised liquid medium. BCR proved to be more adequate than STR in supporting MnP production, leading to 3700 U dm?3 after 144 h with a productivity of 25.7 U dm?3 h?1. On a comparative basis with other production data in lab‐scale reactors, these results appear to be compatible with scale transfer. Copyright © 2006 Society of Chemical Industry 相似文献
88.
89.
Maurizio Bianchi Federico Ferioli Massimiliano Petracci Maria Fiorenza Caboni Claudio Cavani 《European Food Research and Technology》2009,229(2):339-348
The influence of dietary lipid source [animal fats (AF) and vegetable oils (VO)] on quality characteristics of raw chicken
meat (breast, thigh and meat batter) and cooked breaded patties prepared using a conventional technology (CT; forming, battering,
breading, frying and convection cooking) or innovative technology (IT; forming, pre-dusting, steam cooking, battering and
frying) was evaluated. Overall, dietary lipid source did not influence the chemical composition of raw meat while it modified its colour (L*, a*, b*). With respect to AF, VO produced higher breast and thigh meat cooking losses as well as a lower moisture and
higher protein content of cooked breaded patties. VO also determined an increase of polyunsaturated-to-saturated fatty acid
ratio of both raw and processed meat. Despite the different fatty acid profiles, the oxidative status of lipids was not affected
by dietary lipid source and was acceptable in both raw meat and cooked patties as indicated by peroxide and thiobarbituric
acid reactive substance values. As for the processing technology, IT determined a higher moisture and lower lipid content
of the cooked breaded patties. Moreover, lipolysis degree was slightly higher in the products coming from IT. Finally, patties
from AF group were lighter and more yellow than products belonging to VO group whereas IT led to lighter, less red and more
yellow patties in comparison to CT. 相似文献
90.
Sixteen cases of fibrocystic breast disease at different histopathologic stages were examined with the leukocyte adherence inhibition assay. Skeletal muscle and gastric carcinoma extracts were used as controls. The glass adherence of leukocytes from patients affected by fibrocystic breast disease was more inhibited when extracts from breasts with fibrocystic disease were used rather than control extracts. Nonadherence indexes (NAIs) were high in 8 cases, around 20 in 4 cases, a little above zero in 2 cases and below zero in 2 cases. NAIs were related to the histopathologic stage: the highest NAIs were found in 8 cases of classic fibrocystic disease, the lowest in 1 case of simple breast fibrosis. 相似文献