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Lumped parameter analytic modeling and behavioral simulation of a 3-DOF MEMS gyro-accelerometer

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Acta Mechanica Sinica 2015年第6期31卷 910-919页

作者： Payal Verma sandeep k.Arya Ram Gopal MEMS & Micro-sensors Group CSIR – Central Electronics Engineering Research Institute Department of Electronics & Communication Engineering Guru Jambheshwar University of Science & Technology

A new analytical model of a 3-degree-of-freedom （3-DOF） gyro-accelerometer system consisting of a 1-DOF drive and 2-DOF sense modes is presented. The model constructs lumped differential equations associated with each DOFof the system by vector analysis. The coupled differential equations thus established are solved analytically for their responses in both the time and frequency domains. Considering these frequency response equations, novel device design concepts are derived by forcing the sense phase to zero, which leads to a certain relationship between the structural frequencies, thereby causing minimization of the damping effect on the performance of the system. Furthermore, the feasibility of the present gyro-accelerometer structure is studied using a unique discriminatory scheme for the detection of both gyro action and linear acceleration at their events. This scheme combines the formulated settled transient solution of the gyro-accelerometer with the processes of synchronous demodulation and filtration, which leads to the in-phase and quadrature components of the system＇s output signal. These two components can be utilized in the detection of angular motion and linear acceleration. The obtained analytical results are validated by simulation in a MATLAB/Simulink environment, and it is found that the results are in excellent agreement with each other.

关键词： Microelectromechanical systems (MEMS) ·Multimeasurement system. Gyro-accelerometer Gyro-accelerometer model - Transient model

Experimental study of sand grains behavior at their contacts with force-and displacement-controlled sliding tests

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Underground Space 2017年第1期2卷 38-44页

作者： k.Senetakis C.S.sandeep City University of Hong kong Hong Kong

Discrete element modeling requires the proper quantification of the behavior of grains at their contacts including the normal force-displacement and tangential force-displacement relationships to be used as input for contact modeling *** paper reports on recent advances in soil mechanics experimentation which allowed measuring the grain contact behavior of small sand particles quantifying friction and stiffness with sliding tests of a force-controlled or displacement-controlled *** particular focus of this work is on the micromechanical behavior of quartz type grains of size between about 1 and 5 mm.A description of the developed micromechanical apparatus at City University of Hong kong is first discussed and its important different capabilities with previously developed apparatus is briefly ***,a limited set of new data is reported and discussed along with a review of recently acquired results published in the literature associated with the contact behavior of quartz sand *** sliding tests have covered a wider range of normal contact forces from about 0.5 to 8 N,and the results indicated that,for this range of confining forces,there is not any notable change of the inter-particle coefficient of friction.

关键词： Micro-mechanics Inter-particle friction Inter-particle stiffness LBS grains Experimental mechanics

Microstructure transformations and improving wear resistance of austenitic stainless steel additively fabricated by arc-based DED process

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Defence Technology（防务技术） 2024年第8期38卷 194-204页

作者： Ashish Yadav Manu Srivastava Prashant k.Jain sandeep Rathee Hybrid Additive Manufacturing Laboratory Mechanical Engineering DepartmentPDPM Indian Institute of Information TechnologyDesign&ManufacturingJabalpur482005Madhya PradeshIndia FFF Laboratory Mechanical Engineering DepartmentPDPM Indian Institute of Information TechnologyDesign&ManufacturingJabalpur482005Madhya PradeshIndia Department of Mechanical Engineering National Institute of TechnologySrinagarIndia

In this study, austenitic stainless steel(ASS) was additively fabricated by an arc-based direct energy deposition(DED) technique. Macrostructure, microstructure, mechanical characteristics at different spatial orientations(0°, 90°, and 45°), and wear characteristics were evaluated at the deposited structure top, middle, and bottom regions. Results show that austenite(γ) and delta-ferrite(δ) phases make up most of the microstructure of additively fabricated SS316LSi steel. Within γ matrix, δ phase is dispersed both(within and along) grain boundaries, exhibiting a fine vermicular morphology. The bottom, middle,and top regions of WAAM deposited ASS exhibit similar values to those of wrought SS316L in the tensile and impact test findings. Notably, a drop in hardness values is observed as build height increases. During SEM examinations of fractured surfaces from tensile specimen, closed dimples were observed, indicating good ductility of as-built structure. Wear test findings show signs of mild oxidation and usual adhesive wear. By depositing a mechanically mixed composite layer, an increase in the oxidation percentage was discovered to facilitate healing of worn surfaces. The findings of this study will help in design, production and renovation of products/components that are prone to wear. WAAM-deposited ASS has remarkable strength and ability to withstand impacts;it can be used in the production of armour plates for defence applications, mainly military vehicles and aircraft.

关键词： Metal additive deposition Defence applications Arc-based DED Characterization Wear behaviour Fractography

Structural,electronic,magnetic and optical properties of neodymium chalcogenides using LSDA+U method

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Journal of Semiconductors 2012年第8期33卷 9-14页

作者： A Shankar D P Rai sandeep R k Thapa Condensed Matter Theory Group Department of PhysicsMizoram UniversityAizawlMizoram-796004India

We have studied the electronic, magnetic and optical properties of neodymium chalcogenides by performing LSDA＋ U and full potential linearized augmented plane wave （FP-LAPW） method. The electronic structure calculation shows that the electronic states in Nd-chalcogenides were mainly contributed by Nd-4f electrons near Fermi energy and 3p, 4p and 5p state electrons of X （S, Se and Te）, respectively. We have also studied the absorption of light via the imaginary parts of the dielectric function of Nd-chalcogenides.

关键词： DFT DOS magnetic moment U

Low power digitally controlled oscillator designs with a novel 3-transistor XNOR gate

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Journal of Semiconductors 2012年第3期33卷 52-59页

作者： Manoj kumar sandeep k.Arya Sujata Pandey Department of Electronics&Communication Engineering Guru Jambheshwar University of Science&Technology Amity University

Digital controlled oscillators（DCOs） are the core of all digital phase locked loop（ADPLL） circuits. Here,DCO structures with reduced hardware and power consumption having full digital control have been proposed. Three different DCO architectures have been proposed based on ring based ***,four and five bit controlled DCO with NMOS,PMOS and NMOS PMOS transistor switching networks are presented.A three-transistor XNOR gate has been used as the inverter which is used as the delay *** has been controlled digitally with a switch network of NMOS and PMOS *** three bit DCO with one NMOS network shows frequency variations of 1.6141-1.8790 GHz with power consumption variations 251.9224-276.8591μW. The four bit DCO with one NMOS network shows frequency variation of 1.6229-1.8868 GHz with varying power consumption of 251.9225-278.0740μW.A six bit DCO with one NMOS switching network gave an output frequency of 1.7237-1.8962 GHz with power consumption of 251.928-278.998μ*** frequency and power consumption results for 4 6 bit DCO circuits with one PMOS and NMOS PMOS switching network have also been *** phase noise parameter with an offset frequency of 1 MHz has also been reported for the proposed *** with earlier reported circuits have been made and the present approach shows advantages over previous circuits.

关键词： digital control oscillator delay cell power consumption voltage controlled oscillators

Model based odia numeral recognition using fuzzy aggregated features

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Frontiers of Computer Science 2014年第6期8卷 916-922页

作者： Tusar kanti MISHRA Banshidhar MAJHI Pankaj k SA sandeep PANDA Department of Computer Science and Engineering National Institute of Technology Rourkela 769008 India

In this paper, an efficient scheme for recognition of handwritten Odia numerals using hidden markov model （HMM） has been proposed. Three different feature vectors for each of the numeral is generated through a polygonal approximation of object contour. Subsequently, aggregated feature vector for each numeral is derived from these three primary feature vectors using a fuzzy inference system. The final feature vector is divided into three levels and interpreted as three different states for HMM. Ten different three-state ergodic hidden markov models （HMMs） are thus constructed corresponding to ten numeral classes and parameters are calculated from these models. For the recognition of a probe numeral, its log-likelihood against these models are computed to decide its class label. The proposed scheme is implemented on a dataset of 2500 handwritten samples and a recognition accuracy of 96.3% has been achieved. The scheme is compared with other competent schemes.

关键词： handwritten character recognition HMM pattern recognition Odia numeral OCR

Synergistic effect of hybrid Himalayan Nettle/Bauhinia-vahlii fibers on physico-mechanical and sliding wear properties of epoxy composites

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Defence Technology（防务技术） 2020年第4期16卷 762-776页

作者： sandeep kumar kkSMer Brijesh Gangil Vinay kumar Patel Department of Mechanical Engineering S.O.E.T.H.N.B.Garhwal UniversitySrinagar-Garhwal246174UttarakhandIndia Department of Mechanical Engineering Govind Ballabh Pant Institute of Engineering and Technology GhurdauriPauri Garhwal246001UttarakhandIndia

The cellulosic bast fibers are recognized as a justifiable and biodegradable substitute for producing moderate strength polymer composite materials because of their characteristics of renewability,ecofriendliness,and higher specific *** the aim of this research work is to fabricate Himalayan bast fibers(Nettle fiber(NF)/bauhinia vahlii fiber(BF)) based mono/hybrid epoxy composites at varying weight percentage of 2-6 wt% and evaluate the physical(void fraction and water absorption),mechanical(tensile strength,flexural strength,hardness) and sliding wear properties of as-fabricated *** 6 wt% NBF reinforced composites exhibited higher mechanical properties as compared to NF and BF composites with tensile strength of 34.04 MPa,flexural strength of 42.45 MPa,and hardness of 37.01 Hv *** influence of various control factors(sliding velocity,NF/BF/NBF contents,normal load and sliding distance) on specific sliding wear rate of composites was evaluated by Taguchi(three factors at three levels) experimental design and the percentage contribution of these selected parameters on sliding wear performance was examined by Analysis of variance(ANOVA).The sliding wear property of as-developed composites was found to be greatly influenced by sliding velocity and the wear resistance was observed to be improved with the NF/BF/NBF *** wear mechanism of the as-fabricated composites has been elucidated by scanning electron microscopy *** research outcomes demonstrated that the hybridization of Bauhinia vahlii fiber with Nettle fiber led to improve the mechanical and wear properties of epoxy composites.

关键词： Natural fiber Physical properties Mechanical properties Wear properties Taguchi analysis

Pharmacokinetic, pharmacodynamic, and neurochemical investigations of lamotrigine-pentylenetetrazole kindled mice to ascertain it as a reliable model for clinical drug-resistant epilepsy

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Animal Models and Experimental Medicine 2020年第3期3卷 245-255页

作者： sandeep kumar Rajesh k.Goel Department of Pharmaceutical Sciences&Drug Research Punjabi UniversityPatialaPunjabIndia

Background:Pentylenetetrazole kindling has long been used for the screening of investigational antiseizure *** presence of lamotrigine,at a very low dose,does not hamper kindling in mice;rather it modifies this epileptogenesis process into drug-resistant *** lamotrigine-pentylenetetrazole kindled mice show resistance to lamotrigine,phenytoin,and *** may also be possible that other licensed antiseizure drugs,like the mentioned drugs,remain ineffective in this model;therefore,this was the subject of this ***:Swiss albino mice were kindled with pentylenetetrazole for 35 days in the presence of either methylcellulose vehicle or lamotrigine(subtherapeutic dose,ie,5 mg/kg).Vehicle vs lamotrigine-kindled mice were compared in terms of(a)resistance/response toward nine antiseizure drugs applied as monotherapies and two drug combinations;(b)lamotrigine bioavailability in blood and brain;(c)blood-brain barrier integrity;and(d)amino acids and monoamines in the cerebral cortex and ***:Lamotrigine vs vehicle-kindled mice are similar(or not significantly different P>.05 from each other)in terms of(a)response toward drug combinations;(b)lamotrigine bioavailability;and(c)blood-brain barrier integrity except for,significantly(Pkindled mice show significant(Pkg),levetiracetam(40 mg/kg);carbamazepine(40 mg/kg),zonisamide(100 mg/kg),gabapentin(224 mg/kg),pregabalin(30 mg/kg),phenytoin(35 mg/kg),and topiramate(300 mg/kg).Conclusion:Lamotrigine-pentylenetetrazole kindling takes longer to develop(~5 weeks)in comparison to lamotrigine-amygdale(~4 weeks)and lamotriginecorneal(~2 weeks)kindling ***,drug screening through this model may yield superior drugs with novel antiseizure mechanisms.

关键词： animal models drug-resistant epilepsy kindling lamotrigine refractory epilepsy

Capacitance-voltage analysis of a high-k dielectric on silicon

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Journal of Semiconductors 2012年第2期33卷 10-13页

作者： Davinder Rathee sandeep k.Arya Mukesh kumar Department of Electronics and Communication Engineering Guru Jambeshwer University of Science and TechnologyHisarIndia Department of Electronics Science Kurukshetra UniversityKurukshetraIndia

Device characteristics of TiO;gate dielectrics deposited by a sol-gel method and DC sputtering method on a P-type silicon wafer are ***-oxide-semiconductor capacitors with Al as the top electrode were fabricated to study the electrical properties of TiO;*** films were physically characterized by using X-ray diffraction,a capacitor voltage measurement,scanning electron microscopy,and by spectroscopy *** XRD and DST-TG indicate the presence of an anatase TiO;phase in the *** deposited at higher temperatures showed better *** dielectric constant calculated using the capacitance voltage measurement was found to be 18 and 73 for sputtering and sol-gel samples *** refractive indices of the films were found to be 2.16 for sputtering and 2.42 for sol-gel samples.

关键词： sol-gel method DC reactive sputtering C-V analysis flat band voltage