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61.
Praveen V. Pol Sanjaykumar L. Patil Sanjeev Kumar Pandey 《International Journal of Electronics》2013,100(12):1864-1884
This paper proposes an overcurrent protection (OCP) circuit for power MOSFETs employed in low voltage power converters. The proposed configuration requires only discrete components with a gate driver IC and uses the voltage drop across the device for overcurrent detection. It can operate independently in cycle-by-cycle shutdown and multiple cycle shutdown modes. In coordination with a micro-controller based driver IC input signal generator and controller, the proposed OCP circuit can also operate in a single cycle latch-up and hiccup OCP modes. The performance of the proposed scheme is evaluated experimentally at both, hard and soft fault conditions. By experimentation, it is shown that the proposed circuit can operate in various protection modes and capable of protecting a MOSFET in both, hard and soft fault conditions. 相似文献
62.
Sanjeev Jain Sheng-Lyang Jang Jhin-Fang Huang 《Analog Integrated Circuits and Signal Processing》2013,76(2):161-166
This letter presents a fully integrated BiCMOS quadrature voltage-controlled oscillator (QVCO). The QVCO consists of two nMOSFET cross-coupled oscillator stacked in series with source degenerated HBT transistors. SiGe HBT introduces low flicker noise compared to CMOS devices. To generate quadrature phase signals with strong coupling strength, the proposed design uses two MOS-coupled LC-tank cores instead of passive device-coupled cores. This source degeneration topology can improve the phase noise performance of the QVCO as compared to the sub-VCO. The proposed QVCO has been implemented with the TSMC 0.18 μm SiGe 3P6M BiCMOS process, can generate quadrature signals in the frequency range of 4.52–5.05 GHz with core power consumption of 5.76 mW at the dc bias of 1.8 V. At 4.53 GHz, phase noise at 1 MHz offset is ?124.52 dBc/Hz. The die area of the fabricated prototype is 0.453 × 0.898 mm2. 相似文献
63.
Jung-Jae Park Min-Wook Lee Sam S. Yoon Ho-Young Kim Scott C. James Stephen D. Heister Sanjeev Chandra Woon-Ha Yoon Dong-Soo Park Jungho Ryu 《Journal of Thermal Spray Technology》2011,20(3):514-522
Characteristics of supersonic flow are examined with specific regard to nano-particle thin-film coating. Effects of shockwaves,
nozzle geometry, chamber pressure, and substrate location were studied computationally. Shockwaves are minimized to reduce
fluctuations in flow properties at the discontinuities across diamond shock structures. Nozzle geometry was adjusted to ensure
optimal expansion (i.e., P
exit = P
ambient), where shock formation was significantly reduced and flow kinetic energy maximized. When the ambient pressure was reduced
from 1 to 0.01316 bar, the nozzle’s diverging angle must be increased to yield the optimum condition of minimized adversed
effects. Beyond some critical distance, substrate location did not seem to be a sensitive parameter on flow characteristics
when P
amb = 0.01316 bar; however, overly close proximity to the nozzle exit caused flow disturbances inside the nozzle, thereby adversely
affecting coating gas flow. 相似文献
64.
65.
Manjunatha Pattabi S. C. Gurumurthy Ganesh Sanjeev A. B. Gaikwad 《Journal of Materials Science: Materials in Electronics》2011,22(8):1095-1100
Results of the investigations carried out on the electrical behavior of silver particulate films deposited on electron beam
irradiated polystyrene (PS) coated substrates held at a temperature of 455 K in a vacuum of 8 × 10−6 torr at a constant deposition rate of 0.4 nm/s are reported. It is known that when metals are evaporated on to softened polymer
substrates, subsurface particulate structures are formed whose morphology is dependent on deposition parameters. Further,
it was shown that the morphology is dependent on polymer-metal interaction. The present work demonstrates that the polymer-metal
interaction can be brought about in inert polymers like PS by electron irradiation. The results indicate that the films deposited
on PS irradiated to a dose of 20 and 25 kGy gives rise to smaller clusters with smaller inter-cluster separation, better suited
for sensor applications. The induced polymer-metal interaction is attributed to the creation of free radicals due to the 8 MeV
electron irradiation. 相似文献
66.
The purpose of this study was to evaluate the influences of intrinsic drug mechanical properties and different granulation binder delivery processes on the physical and mechanical properties of high drug load granulations after wet granulation. Formulations (80% w/w) of acetaminophen (APAP), metformin and aspirin, which are brittle, viscoelastic, and ductile, respectively; were granulated by high-shear wet granulation. Two modes of binder delivery for wet granulation, either conventional or binder foam, were investigated. Particle size, surface area and pore size of the granulations were characterized. Compacts were prepared at a solid fraction of 0.9 under tri-axial decompression and Hiestand indices (worst-case bonding index (BIw) and brittle fracture index (BFI)) of the compacts were determined. APAP formulations exhibited the smallest geometric mean particle sizes (dg) and showed only slight differences in dg values between the two granulation processes. Binder delivery mode affected mechanical properties of the granulated model drugs differently. Foam granulation appeared to enhance the granule plasticity for APAP while aspirin showed a mixed deformation mechanism based on both its high BIw and high BFI values. The higher BIw value for aspirin after foam granulation may be attributed to improved binder distribution among particles during granulation. On the other hand, conventional wet granulation improved the plasticity of metformin as measured by the higher BIw and lower BFI values. Therefore, conventional wet granulation process conferred advantages in manufacturability and product quality for metformin; as compared to foam granulation which did not enhance plasticity for metformin. Based on this study, a wet granulation process can be selected based on knowledge of the intrinsic drug mechanical properties. 相似文献
67.
68.
Glen Besterfield Sanjeev Nichani Autar K. Kaw Thomas Eason 《Canadian Metallurgical Quarterly》2003,8(4):204-211
To simulate a trunnion-hub-girder (THG) assembly for bascule bridges, two full-scale laboratory tests were conducted for quantifying stresses at previously observed failure locations and for identifying a favorable assembly procedure. One assembly procedure, AP#1, cools the trunnion for a shrink fit into the hub, followed by cooling of the trunnion-hub assembly to shrink fit it into the girder. Using AP#1, development of cracks on the hub was observed in one THG assembly, and, in yet another assembly, the trunnion got stuck in the hub before full insertion could take place. Large hoop stresses and low temperatures were observed at the trunnion-hub interface when the trunnion-hub assembly was cooled for insertion into the girder. Since fracture toughness of THG parts decreases with temperature, allowable crack lengths were small. In an alternative assembly procedure, AP#2, where the hub is shrink fitted into the girder first, followed by cooling the trunnion and shrink fitting it into the hub-girder assembly, the allowable crack length was determined to be double the allowable crack length of AP#1. Hence, for the given full-scale geometry and interference values, assembly procedure AP#2 was found to be better than AP#1. 相似文献
69.
Yunshu Zhang Yogesh Sahai Robert A. Rapp Sanjeev Gupta 《Metallurgical and Materials Transactions B》2002,33(2):315-319
The experimentally well-known alumina solubility in the range of acidic to neutral cryolite-base melts has been modeled thermodynamically
in terms of several oxyfluoride solutes. For an acidic melt, cryolite ratio r=1.5, the dominant solute is monoxygen Na2Al2OF6. In a less acidic regime, dioxygen Na2Al2O2F4 is dominant, whereas for neutral compositions (r=3), Na4Al2O2F6 starts to gain importance. The fit of the model to the experimental solubility data is virtually perfect. The values of the
equilibrium constants for the formation of the individual solutes are reported. The formation and conversion of these oxyfluoride
complexes serve as an effective buffer opposing change in the melt basicity. 相似文献
70.
ABSTRACTIn the present work, the self-organized pattern formation with simultaneous surface smoothing of Polyethylene terephthalate (PET) by 40 keV Ar+ ions irradiation has been discussed. The effect of most important experimental parameter i.e. ion beam incidence that control these processes has been discussed by varying off normal incidences from 300 to 500. The changes in surface topography have been studied using Atomic Force Microscopy (AFM). It has been investigated from AFM analysis that oblique ion beam induced sputtering significantly reduced the surface roughness with simultaneous formation of some hillock and hole like structures. 相似文献