Perspective of buried oxide thickness variation on triple metal-gate (TMG) recessed-S/D FD-SOI MOSFET

Recently, Fully-Depleted Silicon on Insulator (FD-SOI) MOSFETs have been accepted as a favourable technology beyond nanometer nodes, and the technique of Recessed-Source/Drain (Re-S/D) has made it more immune in regards of various performance factors. However, the proper selection of Buried-Oxide (BOX) thickness is one of the major challenges in the design of FD-SOI based MOS devices in order to suppress the drain electric penetrations across the BOX interface efficiently. In this work, the effect of BOX thickness on the performance of TMG Re-S/D FD-SOI MOSFET has been presented at 60 nm gate length. The perspective of BOX thickness variation has been analysed on the basis of its surface potential profile and the extraction of the threshold voltage by performing two-dimensional numerical simulations. Moreover, to verify the short channel immunity, the impact of gate length scaling has also been discussed. It is found that the device attains two step-up potential profile with suppressed short channel effects. The outcomes reveal that the Drain Induced Barrier Lowering (DIBL) values are lower among conventional SOI MOSFETs. The device has been designed and simulated by using 2D numerical ATLAS Silvaco TCAD simulator

Thermally actuated shape-memory polymers: Experiments, theory, and numerical simulations

With the aim of developing a thermo-mechanically-coupled large-deformation constitutive theory and a numerical-simulation capability for modeling the response of thermally-actuated shape-memory polymers, we have (i) conducted large strain compression experiments on a representative shape-memory polymer to strains of approximately unity at strain rates of 10[superscript −3] s[superscript −1] and 10[superscript −1] s[superscript −1], and at temperatures ranging from room temperature to approximately 30C above the glass transition temperature of the polymer; (ii) formulated a thermo-mechanically-coupled large-deformation constitutive theory; (iii) calibrated the material parameters appearing in the theory using the stress-strain data from the compression experiments; (iv) numerically implemented the theory by writing a user-material subroutine for a widely-used finite element program; and (v) conducted representative experiments to validate the predictive capability of our theory and its numerical implementation in complex three-dimensional geometries. By comparing the numericallypredicted response in these validation simulations against measurements from corresponding experiments, we show that our theory is capable of reasonably accurately reproducing the experimental results. As a demonstration of the robustness of the three-dimensional numerical capability, we also show results from a simulation of the shape-recovery response of a stent made from the polymer when it is inserted in an artery modeled as a compliant elastomeric tube.National Science Foundation (U.S.) (grant DMI-0517966)Singapore-MIT Allianc

Sr-Nd isotope geochemistry of the early Precambrian sub-alkaline mafic igneous rocks from the southern Bastar craton, Central India

Sr–Nd isotope data are reported for the early Precambrian sub-alkaline mafic igneous rocks of the southern Bastar craton, central India. These mafic rocks are mostly dykes but there are a few volcanic exposures. Field relationships together with the petrological and geochemical characteristics of these mafic dykes divide them into two groups; Meso-Neoarchaean sub-alkaline mafic dykes (BD1) and Paleoproterozoic (1.88 Ga) sub-alkaline mafic dykes (BD2). The mafic volcanics are Neoarchaean in age and have very close geochemical relationships with the BD1 type. The two groups have distinctly different concentrations of high-field strength (HFSE) and rare earth elements (REE). The BD2 dykes have higher concentrations of HFSE and REE than the BD1 dykes and associated volcanics and both groups have very distinctive petrogenetic histories. These rocks display a limited range of initial 143Nd/144Nd but a wide range of apparent initial 87Sr/86Sr. Initial 143Nd/144Nd values in the BD1 dykes and associated volcanics vary between 0.509149 and 0.509466 and in the BD2 dykes the variation is between 0.510303 and 0.510511. All samples have positive εNd values the BD1 dykes and associated volcanics have εNd values between +0.3 and +6.5 and the BD2 dykes between +1.9 to +6.0. Trace element and Nd isotope data do not suggest severe crustal contamination during the emplacement of the studied rocks. The positive εNd values suggest their derivation from a depleted mantle source. Overlapping positive εNd values suggest that a similar mantle source tapped by variable melt fractions at different times was responsible for the genesis of BD1 (and associated volcanics) and BD2 mafic dykes. The Rb–Sr system is susceptible to alteration and resetting during post-magmatic alteration and metamorphism. Many of the samples studied have anomalous apparent initial 87Sr/86Sr suggesting post-magmatic changes of the Rb–Sr system which severely restricts the use of Rb–Sr for petrogenetic interpretation

A thermo-mechanically-coupled large-deformation theory for amorphous polymers in a temperature range which spans their glass transition

Amorphous thermoplastic polymers are important engineering materials; however, their non-linear, strongly temperature- and rate-dependent elastic-viscoplastic behavior is still not very well understood, and is modeled by existing constitutive theories with varying degrees of success. There is no generally agreed upon theory to model the large-deformation, thermo-mechanically-coupled, elastic-viscoplastic response of these materials in a temperature range which spans their glass transition temperature. Such a theory is crucial for the development of a numerical capability for the simulation and design of important polymer processing operations, and also for predicting the relationship between processing methods and the subsequent mechanical properties of polymeric products. In this paper we extend our recently published theory [Anand, L., Ames, N. M., Srivastava, V., Chester, S. A., 2009. A thermo-mechanically-coupled theory for large deformations of amorphous polymers. Part I: formulation. International Journal Plasticity 25, 1474–1494; Ames, N. M., Srivastava, V., Chester, S. A., Anand, L., 2009. A thermo-mechanically coupled theory for large deformations of amorphous polymers. Part II: applications. International Journal of Plasticity 25, 1495–1539] to fill this need. We have conducted large strain compression experiments on three representative amorphous polymeric materials – a cyclo-olefin polymer (Zeonex-690R), polycarbonate (PC), and poly(methyl methacrylate) (PMMA) – in a temperature range from room temperature to approximately 50 °C above the glass transition temperature, ϑg [theta subscript g], of each material, in a strain-rate range of ≈10-4 [10 superscript -4]to 10-1 s-1 [10 superscript -1 s superscript -1], and compressive true strains exceeding 100%. We have specialized our constitutive theory to capture the major features of the thermo-mechanical response of the three materials studied experimentally. We have numerically implemented our thermo-mechanically-coupled constitutive theory by writing a user material subroutine for a widely used finite element program. In order to validate the predictive capabilities of our theory and its numerical implementation, we have performed the following validation experiments: (i) a plane-strain forging of PC at a temperature below ϑg [theta subscript g], and another at a temperature above ϑg [theta subscript g]; (ii) blow-forming of thin-walled semi-spherical shapes of PC above ϑg [theta subscript g]; and (iii) microscale hot-embossing of channels in Zeonex and PMMA above ϑg [theta subscript g]. By comparing the results from this suite of validation experiments of some key features, such as the experimentally-measured deformed shapes and the load-displacement curves, against corresponding results from numerical simulations, we show that our theory is capable of reasonably accurately reproducing the experimental results obtained in the validation experiments.National Science Foundation (U. S.) (Grant no. DMI-0517966)Singapore MIT Alliance Programme in Manufacturing Systems and Technolog

C-type natriuretic peptide and brain natriuretic peptide inhibit adenylyl cyclase activity: interaction with ANF-R2/ANP-C receptors

AbstractC-type natriuretic peptide (CNP) and brain natriuretic peptide (BNP) are members of the natriuretic peptide family, which have been shown to interact with ANP-C/ANF-R2 receptors in addition to ANP-B receptor subtypes. The present study was undertaken to investigate if the interaction of CNP and BNP with ANP-C receptors results in the inhibition of adenylyl cyclase activity. CNP and BNP inhibited adenylyl cyclase activity in heart and brain striatal membranes in a concentration dependent manner with an apparent Ki between 0.1 and 1.0 nM. Maximal inhibition observed in heart membranes were about 25% and 35% for BNP and CNP respectively, however the inhibitions in brain striatal membranes were smaller (∼2%). The inhibition was dependent on the presence of guanine nucleotides and was attenuated by pertussis toxin treatment. In addition, CNP inhibited the stimulatory effect of isoproterenol on adenylyl cyclase, whereas CNP as well as BNP showed an additive effect with the inhibitory response of angiotensin II on adenylyl cyclase activity. When the combined effect of C-ANF4−23/BNP, C-ANF4−23/CNP and BNP/CNP at optimal concentrations was studied together on adenylyl cyclase activity, the percent inhibition remained the same for C-ANF4−23 and BNP or C-ANF4−23 and CNP, however, an additive inhibitory effect was observed for BNP and CNP. These results suggest that CNP and BNP like C-ANF4−23 interact with ANP-C receptors and result in the inhibition of adenylyl cyclase activity. On the other hand, CNP and BNP interact with the ANP-C receptor, however, the interaction may be at different sites or there may be two subpopulations of ANP-C receptors specific for each of the peptides. These results indicate that BNP and CNP, like ANP and C-ANF4−23, inhibit the adenylyl cyclase/cAMP signal transduction system through an inhibitory guanine nucleotide regulatory protein, by interacting with ANP-C receptor subtypes