In this paper, bulk-Si metal–oxide–semiconductor field effect transistors (MOSFETs) are fabricated using the catalytic chemical vapor deposition (Cat-CVD) method as an alternative technology to the conventional high-temperature thermal chemical vapor deposition. Particularly, formation of low-resistivity phosphorus (P)-doped poly-Si films is attempted by using Cat-CVD-deposited amorphous silicon (a-Si) films and successive rapid thermal annealing (RTA) of them. Even after RTA processes, neither peeling nor bubbling are observed, since hydrogen contents in Cat-CVD a-Si films can be as low as 1.1%. Both the crystallization and low resistivity of 0.004 Ω·cm are realized by RTA at 1000 °C for only 5 s. It is also revealed that Cat-CVD SiNx films prepared at 250 °C show excellent oxidation resistance, when the thickness of films is larger than approximately 10 nm for wet O2 oxidation at 1100 °C. It is found that the thickness required to stop oxygen penetration is equivalent to that for thermal CVD SiNx prepared at 750 °C. Finally, complementary MOSFETs (CMOSs) of single-crystalline Si were fabricated by using Cat-CVD poly-Si for gate electrodes and SiNx films for masks of local oxidation of silicon (LOCOS). At 3.3 V operation, less than 1.0 pA μm−1 of OFF leakage current and ON/OFF ratio of 107–108 are realized, i.e. the devices can operate similarly to conventional thermal CVD process. 相似文献
β-dicalcium silicate synthesized by thermal dissociation of hydrothermally prepared hillebrandite (Ca2(SiO3)(OH)2) exhibits extremely high hydration activity. Characterization of the hydrates obtained and investigation of the hydration mechanism was carried out with the aid of trimethylsilylation analysis, 29Si magic angle spinning nuclear magnetic resonance, transmission electron microscopy selected area electron diffraction, and XRD. The silicate anion structure of C-S-H consisted mainly of a dimer and a single-chain polymer. Polymerization advances with increasing curing temperature and curing time. The C-S-H has an oriented fibrous structure and exhibits a 0.73-nm dreierketten in the longitudinal direction. On heating, the C-S-H dissociates to form β-C2S. The temperature at which βC2S begins to form decreases with increasing chain length of the C-S-H or as the Ca/Si ratio becomes higher. The high activity of β-C2S is due to its large specific surface area and the fact that the hydration is chemical-reaction-rate-controlled until its completion. As a result, the hydration progresses in situ and C-S-H with a high Ca/Si ratio is formed. 相似文献
Comments on the article Proverbs as psychological theories...or is it the other way around by Tim Rogers (see record 1991-03999-001). Since Rogers cites the author's own investigation of proverbs (1988)--later expanded into a book-length treatment of popular beliefs (1990)--the author shares his bemuscinent over his continued admiration for oftrepeated beliefs that are demonstrably false and, in some instances (e.g., "Spare the rod and spoil the child"), dangerous. Because he cannot defend the truth value of proverbs, Rogers decides instead to challenge truth as the relevant criterion for judging them. Similarly, even though proverbs A and B may well contradict one another (e.g., Absence makes the heart grow fonder vs. Out of sight, out of mind), he denies that this is troubling since, after all, A will apply in one situation and B in another. Anyone who is not satisfied with this defense is said to be a partisan of "a natural science model of psychology" (p. 200), "logical empiricism," or something he calls "eliminative materialism." (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
Istanbul is one of the most famous historical cities in the world. However, the project alignment selected as the best of a range of alignments cannot avoid passing beneath the historical and cultural heritages of Istanbul as well as under ancient and densely inhabited areas of the city. This paper will explain some of the challenges related to the bored tunnels.
Historical buildings are vulnerable. Yet many existing residential and office buildings are old and constructed on minimal foundations. As a consequence, it is vital that any drawdown of groundwater and any ground settlements have to be minimized.
In addition, the connection between the immersed and bored tunnels will be made directly and totally underground, without the usual intermediate shafts and beneath the deep waters of the Bosphorus Strait. This operation needs the utmost control of the tunnel excavation face to ensure its stability and to minimize water ingress. Based on such considerations, tunnel excavation by tunnel boring machine (TBM) using a slurry shield and having the ability to operate under high pore pressures was recommended as the method of excavation for the main running tunnels.
The paper will explain how the design team from Avrasyaconsult – the Employer’s Representative – arrived at the final minimum, specific and functional requirements of the bored tunneling works which are to be carried out using the ‘FIDIC EPC/Turnkey Project’ conditions. 相似文献
BACKGROUND: Bronchoscopic bronchoalveolar lavage in children to investigate bronchial disorders such as asthma has both ethical and procedural difficulties. OBJECTIVE: The aim of this study was to establish a standardized non-bronchoscopic method to perform bronchoalveolar lavage in children attending for elective surgery to obtain normal cellular data. METHODS: Bronchoalveolar lavage was performed on normal children (n = 55) by infusing saline (20 mL) through an 8 FG suction catheter passed after endotracheal intubation. Oxygen saturation, heart and respiratory rate were monitored during the bronchoalveolar lavage procedure. Cellular analysis and total protein estimation of the lavage fluid were performed. Epithelial lining fluid volume was calculated (n = 15) using the urea dilution method. RESULTS: The procedure was well tolerated by all children. Total cell count and differential cell count for children (macrophages 70.8 +/- 2.3%, lymphocytes 3.8 +/- 0.6%, neutrophils 5.7 +/- 1.0%, eosinophils 0.14 +/- 0.03%, epithelial cells 19.6 +/- 2.1%, mast cells 0.21 +/- 0.02%) were similar to those reported for adults. Age and sex comparisons revealed no differences between groups. The mean total protein recovered in the cell free supernatant was 49.72 +/- 4.29 mg/L and epithelial lining fluid volume was 0.82 +/- 0.11% of return lavageate. CONCLUSION: This method allows bronchoalveolar lavage to be performed safely and quickly on children attending for routine elective surgery. Using this method and taking the 'window of opportunity' of elective surgery, the presence or absence of airway inflammation could be studied in children with various patterns of asthma during relatively asymptomatic periods. 相似文献