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141.
Tina M. Briere Marcel H. F. Sluiter Vijay Kumar Yoshiyuki Kawazoe 《Bulletin of Materials Science》2003,26(1):115-116
The geometries of several Mn clusters in the size range Mn13-Mn{on23} are studied via the generalized gradient approximation to density functional theory. For the 13-and 19-atom clusters, the
icosahedral structures are found to be most stable, while for the 15-atom cluster, the bcc structure is more favoured. The
clusters show ferrimagnetic spin configurations. 相似文献
142.
Vijay Srinivasan J. Sami Cuzmar Thomas J. O’keefe 《Metallurgical and Materials Transactions B》1990,21(1):81-86
The presence of excessive lead in zinc sulfate electrolytes can lead to problems related to both processing efficiency and
the properties of the metal produced. For example, poor adhesion can occur in electrogalvanized steel when it is heated in
the temperature range of 215 °C to 280 °C if lead is present in the deposit. The duration of heating necessary to induce the
peeling of the zinc was found to be dependent on the temperature, time, and concentration of lead in the electrolyte and the
plating parameters. The presence of lead slowed the formation of the intermetallic, and the peeling occurred between the zinc
and the iron-zinc intermetallic layer. In order to gain a better fundamental understanding of the role of lead, rotating disc
electrodes were used to measure the diffusion coefficient of lead in the zinc sulfate electrolyte. The experimentally determined
mass transport data on lead can be used as an aid to set an acceptable limit of lead allowable in the electrolyte or to evaluate
the electrochemical characteristics of an electrolytic zinc system. By the addition of strontium carbonate to the plating
solution followed by filtration, the lead concentration in the electrolyte could be reduced to an acceptable level, preventing
the poor adhesion on heating. 相似文献
143.
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145.
Xuemei Wang Vijay Gupta Soumendra N. Basu 《Journal of the American Ceramic Society》2005,88(7):1909-1913
Parameters that characterize interface fracture are defined, and procedures to measure them are discussed. The interface strength σo is measured by using a novel laser spallation experiment, which uses a laser-induced stress wave to separate the interface. The intrinsic ( G o ) and total ( G c ) fracture energies are measured using a double cantilever beam experiment performed at ambient and cryogenic temperatures, respectively. These experiments are used to obtain relationships between G c and G o , and between σo and G o , for interfaces between sputter-deposited polycrystalline Ta coatings and sapphire substrates. The intrinsic toughness and strength were modified by changing the orientation of the sapphire surface (basal and prismatic), while G c was varied by changing the test temperature (ambient and cryogenic) and the thickness (1–3 μm) of the ductile Ta layer. Besides providing values that have interest in their own right, the work presented here provides a general framework for designing interfaces in bonded structures and serves as a basis to develop atomistic and continuum interface fracture models. 相似文献
146.
The demand of low power high density integrated circuits is increasing in modern battery operated portable systems. Sub-threshold region of MOS transistors is the most desirable region for energy efficient circuit design. The operating ultra-low power supply voltage is the key design constraint with accurate output performance in sub-threshold region. Degrading of the performance metrics in Static random access memory (SRAM) cell with process variation effects are of major concern in sub-threshold region. In this paper, a bootstrapped driver circuit and a bootstrapped driver dynamic body biasing technique is proposed to assist write operation which improves the write-ability of sub-threshold 8T-SRAM cell under process variations. The bootstrapped driver circuit minimizes the write delay of SRAM cell. The bootstrapped driver dynamic body bias increases the output voltage levels by boosting factor therefore increasing in switching threshold voltage of MOS devices during hold and read operation of SRAM latch. The increment in threshold voltage improves the static noise margin and minimizing the process variation effects. Monte-Carlo simulation results with 3 \(\sigma \) Gaussian distributions show the improvements in write delay by 11.25 %, read SNM by 12.20 % and write SNM by 12.57 % in 8T-SRAM cell under process variations at 32 nm bulk CMOS process technology node. 相似文献
147.
148.
In this study, the effect of Coriolis force along with the Darcy parameter has been analyzed on time-dependent forced convective boundary layer flow of conducting fluids over a rotating disc embedded in a porous medium. The modeled system is solved by power series approximations in the Mathematica environment shooted values. The significant impact of the rheological properties, such as Darcy parameter and Prandtl number , of water, hydrocarbon, and kerosene-based conducting fluids for the deviation of parameter (Karman) has been noted and then analyzed qualitatively and quantitatively with graphs and tables. 相似文献
149.
150.
Multi-walled carbon nanotubes (MWCNTs)-polymer composite-based hybrid sensors were fabricated and integrated into a resistive sensor design for gas sensing applications. Thin films of MWCNTs were grown onto Si/SiO(2) substrates via xylene pyrolysis using the chemical vapor deposition technique. Polymers like PEDOT:PSS and polyaniline (PANI) mixed with various solvents like DMSO, DMF, 2-propanol and ethylene glycol were used to synthesize the composite films. These sensors exhibited excellent response and selectivity at room temperature when exposed to low concentrations (100 ppm) of analyte gases like NH(3) and NO(2). The effect of various solvents on the sensor response imparting selectivity to CNT-polymer nanocomposites was investigated extensively. Sensitivities as high as 28% were observed for an MWCNT-PEDOT:PSS composite sensor when exposed to 100 ppm of NH(3) and - 29.8% sensitivity for an MWCNT-PANI composite sensor to 100 ppm of NO(2) when DMSO was used as a solvent. Additionally, the sensors exhibited good reversibility. 相似文献