Effect of H2O evolving from TEOS based SiO2 film on the EEPROM cell characteristic

In this paper, we investigate the effect of water (H₂O) molecules evolving from silicon dioxide (SiO₂) film deposited by low pressure chemical vapor deposition (LPCVD) at 670 °C on the transistor characteristic of an electrically erasable programmable read only memory (EEPROM) cell. Fourier Transform Infra red (FT-IR) analysis reveals that H₂O is captured during film deposition and diffused to silicon surface during high thermal processing. The diffused H₂O molecules lower threshold voltage (V_t) of cell transistor and, thus, leakage current of the cell transistor is increased. In erased cell, V_t lowering is 0.25 V in which it increases leakage current of cell transistor from 1 to 100 pA. This results in the lowering of high voltage margin of a 512 Kb EEPROM from 2.8 to 2.6 V at 85 °C.     

Ultrasonic inspection of studs (bolts) using dynamic predictive deconvolution and wave shaping

Bolt degradation has become a major issue in the nuclear industry since the 1980's. If small cracks in stud bolts are not detected early enough, they grow rapidly and cause catastrophic disasters. Their detection, despite its importance, is known to be a very difficult problem due to the complicated structures of the stud bolts. This paper presents a method of detecting and sizing a small crack in the root between two adjacent crests in threads. The key idea is from the fact that the mode-converted Rayleigh wave travels slowly down the face of the crack and turns from the intersection of the crack and the root of thread to the transducer. Thus, when a crack exists, a small delayed pulse due to the Rayleigh wave is detected between large regularly spaced pulses from the thread. The delay time is the same as the propagation delay time of the slow Rayleigh wave and is proportional to the site of the crack. To efficiently detect the slow Rayleigh wave, three methods based on digital signal processing are proposed: wave shaping, dynamic predictive deconvolution, and dynamic predictive deconvolution combined with wave shaping.     

Sol-Gel-Derived Soda Lime-High Silica Glass

Sols containing well-mixed tetraethyl orthosilicate, sodium methylate (CH₃ONa), and Ca metal dissolved in HCIO₄ were hydrolyzed at low pH. After gelation, controlled drying, and subsequent firing at 600°C, the mixture yielded clear glass chunks. Glasses containing 85% to <100% SiO₂, which otherwise are difficult to make by conventional melting techniques, could be made using this technique.     

Overexpression of phospholipase C-gamma1 in rat 3Y1 fibroblast cells leads to malignant transformation

Phospholipase C-gamma1 (PLC-gamma1) mediates signals from various extracellular origins to evoke cellular events such as mitogenesis. Previously, we reported that PLC-gamma1 was highly expressed in colorectal cancer and familial adenomatous polyposis, suggesting that PLC-gamma1 might be oncogenic. In this study, we have established rat 3Y1 fibroblasts that overexpress whole PLC-gamma1 and src homology 2 (SH2)-SH2-SH3 domain of PLC-gamma1. These cells showed a transformed phenotype and were tumorigenic when transplanted into nude mice. These results indicate that overexpression of PLC-gamma1 could transform rat fibroblasts, and the transformation is mediated by SH2-SH2-SH3 domain of PLC-gamma1.     

Neuromuscular interaction between cisatracurium and mivacurium, atracurium, vecuronium or rocuronium administered in combination

We compared the dose-response relationships of cisatracurium, mivacurium, atracurium, vecuronium and rocuronium and examined the interactions of cisatracurium with mivacurium, atracurium, vecuronium and rocuronium in humans by isobolographic and fractional analyses. We studied 180 adult patients during nitrous oxide-fentanyl-propofol anaesthesia. Neuromuscular block was monitored using mechanomyography to detect the twitch response of the ulnar nerve at the wrist. The dose-response curves were determined by probit analysis. The calculated ED50 values and their 95% confidence intervals were 40.9 (38.1-43.7), 49.8 (47.0-52.6), 187.2 (175.1-199.3), 36.6 (34.7-38.5) and 136.4 (129.2-143.6) micrograms.kg-1 for cisatracurium, mivacurium, atracurium, vecuronium and rocuronium, respectively. Corresponding ED95 values were 57.6 (53.5-61.7), 91.8 (88.1-95.5), 253.1 (238.9-267.3), 52.9 (49.1-56.7) and 288.7 (276.2-301.2) micrograms.kg-1, respectively. The interaction between cisatracurium and mivacurium, vecuronium or rocuronium was found to be synergistic, but the interaction between cisatracurium and atracurium was found to be additive. Synergy between cisatracurium and vecuronium or rocuronium was greater than between cisatracurium and mivacurium.     

Abrasive wear mechanisms and the grit size effect

The classical cutting model for abrasive wear deviates from reality in that it cannot predict the effect of grit size on wear and that the observed wear rates are at least an order of magnitude smaller than the predicted values. Through experimental and theoretical work it is shown in this paper that the grit size effect is a consequence of the transition from a cutting mechanism to a sliding wear mechanism. The wear coefficient is shown to be less than that predicted by a cutting model owing to the plastic deformation of the surface being worn.     

Natural convection thermo fluid dynamics in a volumetrically heated rectangular pool

During a severe accident the nuclear reactor core may melt and, further, relocate to the lower plenum in the reactor vessel. Should there be no effective cooling mechanism, the core debris may heat up on account of the volumetric decay heat generation to form a molten pool in natural convection. The Simulant Internal Gravitated Material Apparatus Rectangular Pool (SIGMA RP) tests were performed to study high modified Rayleigh number (Ra′) natural convection in a rectangular pool. The test apparatus was 500 mm long, 500 mm high and 160 mm wide. Forty thin cartridge heaters, with a sheath diameter of 4.2 mm and a length of 600 mm, were used to simulate internal heating in the pool. They were uniformly distributed in the rectangular pool so as to supply a maximum of 2.5 kW power to the pool. Ra′ based on the power input was varied from 10⁹ to 10¹⁴. The working fluid Prandtl number (Pr) ranged from 4 to 8 for water, and 0.7 for air. Particular attention was paid to the Pr influence on natural convection heat transfer in the pool. The relation between the Nusselt number (Nu) and Ra′ was determined for different boundary conditions in the rectangular pool. In one case the upper wall was cooled isothermally, while the lower wall was kept adiabatic. In the other case both the upper and lower walls were cooled isothermally. The experimental results indicated that both the upward and downward natural convection heat transfer rates were affected by Pr. The resultant engineering correlations were applied to simulation of a spectrum of loss-of-coolant accidents to determine the reactor vessel failure time.     

Dual orientation and variant selection during diffusional transformation of austenite to allotriomorphic ferrite

The crystallographic relationship between austenite and grain boundary nucleated allotriomorphic ferrite has been investigated using electron back-scattered diffraction with a view to establishing a mechanism of variant selection. It is possible in some circumstances for the ferrite to adopt a favoured orientation relationship with both of the austenite grains with which it is in contact. However, the theoretical probability for the development of such a dual orientation has in previous work been shown to be very small, although experiments indicate otherwise. In this work, we have discovered experimentally that the probability of dual orientations is significantly increased when adjacent austenite grains are connected by special high-angle boundaries. Crystallographic calculations validate these observations and lead to the conclusion that simultaneous lattice matching between ferrite and its parent austenite grains is more likely in the presence of certain kinds of microscopic texture in the austenite. The phenomenon of dual orientation provides a criterion for crystallographic variant selection during diffusional transformation.