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Dive into the research topics where Ram P. Bajpai is active.

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Featured researches published by Ram P. Bajpai.


Bulletin of Materials Science | 2002

Alcohol sensing of tin oxide thin film prepared by sol-gel process

Sunita Mishra; C. Ghanshyam; Nathai Ram; Satinder Singh; Ram P. Bajpai; R. K. Bedi

The present paper describes the alcohol sensing characteristics of spin coated SnO2 thin film deposited by using sol-gel process. The sensitivity of the film was measured at different temperatures and different concentrations of alcohol at ppm level. Alcohol detection result shows peak sensitivity at 623 K. The variation of sensitivity and ethanol concentration has shown a linear relationship up to 1150 ppm and after that it saturates. The response time measurement of the sensor was also observed and it was found that the response time is 30 sec. The results obtained favour the sol-gel process as a low cost method for the preparation of thin films with a high sensing characteristic.


Vacuum | 2002

Plasma etch models based on different plasma chemistry for micro-electro-mechanical-systems application.

A.K. Paul; A.K. Dimri; Ram P. Bajpai

The suitability of different plasma etch models based on various plasma chemistry has been evaluated for the fabrication of micro-mechanical structures and micro-electro-mechanical systems. Different etch models have been described for silicon etching based on fluorine and chlorine chemistry and the mechanisms involved in SiO2 etching. Conventional planar reactive ion etching systems have been utilized for the etching of SiO2 and silicon based on fluorine and chlorine etch models. Fluorine containing gases such as CHF3 in combination with Ar have been used for SiO2 etching and achieved nearly vertical sidewalls with smooth bottom surface. Gas mixtures such as SF6/O2 at low substrate temperatures and Cl2/BCl3 have been used for silicon etching and sidewall passivation techniques have been employed to achieve vertical sidewalls. The usefulness of chlorine chemistry using BCl3 gas chopping technique for the fabrication of high aspect ratio structures has been demonstrated.


Optical Engineering | 2005

Refractive index and concentration sensing of solutions using mechanically induced long period grating pair

Vandana Mishra; Nahar Singh; Subhash C. Jain; Palvinder Kaur; Ruchi Luthra; Himani Singla; V. K. Jindal; Ram P. Bajpai

We demonstrate the use of a pair of mechanically induced long period gratings (LPGs) for sensing the refractive index and concentration of liquids for which NaCl solutions of different concentrations and standard refractive index liquids are studied. The effect of varying the refractive index and/or concentration is reflected in changing output power loss values at resonance wavelengths. For a concentration change from 5 to 20 g per 100 ml, the maximum variation detected in optical output power is 20 pW, while for a refractive index variation from 1.446 to 1.458, it is 11 pW. These studies are quite useful for chemical, pharmaceutical, biological, and process control sensing applications.


international conference on intelligent sensing and information processing | 2005

Smart-drug delivery system employing molecular motors

S.K. Vashist; R. Tewari; I. Kaur; Ram P. Bajpai; Lalit M. Bharadwaj

A drug delivery system has been envisioned employing actinmyosin molecular motors, liposomes, microcantilevers and a specific track formed by microfilaments. Molecular motors can pull on giant liposomes enclosing the drug to be delivered at the target site. An array of microcantilevers whose deflection in nanometers would cause the opening of the valves responsible for delivering the drug, would be implanted within the liposomes. A particular microfilament network would be designed to provide direction to the molecular motors carrying the liposomes towards the specific target site, where specific biochemical recognition occurs between the immobilized biomolecules adsorbed on the microcantilever surface and the complementary disease biomarkers. The formation of complexes between the complementary biomolecules deflects the microcantilevers causing the opening of the valves, which release the drug at the particular target site.


Optical Engineering | 2005

Mechanically created long-period fiber gratings as sensitive bend sensors

Nahar Singh; Subhash C. Jain; Vandana Mishra; G. C. Poddar; Ashu Kumar Bansal; V. K. Jindal; Ram P. Bajpai

An application of mechanically created long-period fiber grat- ings as sensitive bend sensors in structures and other areas is sug- gested. A resonance splitting of about 10 nm is observed under a maxi- mum bend curvature of 0.4 m 21 , producing a bend sensitivity of 25 nm/m 21 . The design features of the experimental setup developed for the realization of mechanically created long-period fiber gratings and measurement of their output spectrum under different bend curvatures are discussed.


international conference on intelligent sensing and information processing | 2004

Diagnosis of tuberculosis based on BioMEMS

Sandeep Kumar; Ram P. Bajpai; Lalit M. Bharadwaj

The rapid developments in the field of biochemical sciences, immunology, molecular biology and semiconductor microfabrication technology has led to the concept of microdiagnostic kits. The diagnostic principle of nanomechanical deflection of the microcantilever due to adsorption of the antigen 85 complex on its upper surface is employed for the diagnosis of TB. The deflection of the microcantilever would be measured in terms of piezoresistive changes by implanting boron at the anchor point. Such a biomicroelectromechanical system (BioMEMS) based microdiagnostic kit is highly specific as complementary biochemical interactions take place between TB antigens and the antibodies against them immobilized on the upper surface of the microcantilever. Measurement of antigens up to picogram levels can be done using this technique. The paper discusses the various aspects of the development and production of microcantilever based microdiagnostic kit for tuberculosis.


international conference on intelligent sensing and information processing | 2004

Lab-on-a-chip based on BioMEMS

Sandeep Kumar; Ram P. Bajpai; Lalit M. Bharadwaj

Innovative efforts, coupling fundamental biological and chemical sciences with technological advances in the fields of micromachining and microfabrication of silicon chips will lead to the lab-on-a-chip for large-scale diagnosis of diseases. It is a potential tool allowing simultaneous detection of a large number of disease biomarkers in a single step. The device has got tremendous advantages in terms of sensitivity, specificity, cost, time, detection limit, sample requirement and simplicity. Lab-on-a-chip would be made from an array of few hundred microcantilevers with each one of them immobilized with probe DNA/antibodies/receptors specific for their complementary biomolecules. A microcantilever is the ultra-highly sensitive microscopic beam fixed at one end and free at other end. It is just like the diving board that undergoes deflection when some weight is applied to it. Proteins and our genetic blueprint, the DNA, are keys to understand the health and illness. Their qualitative and quantitative detection can be performed economically using such miniaturized microlaboratory with a highly sensitive, simple and label-free microgravimetric assay having the detection limit extending up to picogram range. Although the technology is still in its embryonic stage but with rapid advances in the human genome project, immunology and nanobiotechnology, lab-on-a-chip would be there in the market anytime in the coming decade.


SPIE's International Symposium on Smart Materials, Nano-, and Micro- Smart Systems | 2002

Design simulation of DNA-based electronic components

Lalit M. Bharadwaj; Inderpreet Kaur; Rakesh Kumar; Ram P. Bajpai

The interest in molecular devices is growing and a number of organic molecules are being studied to achieve commercially viable technology in near future. DNA being the only molecule, which can be, synthesizes in any sequence, orientation and length is a potential candidate for fabrication of Nano devices. It is established fact that life processes are governed by communication through out the length of DNA by charge transfer. Thus, the study of charge transfer in DNA is of great importance in understanding and realisation of DNA based biomolecular electronics. We calculated the ionisation potential of all the four bases of DNA using Harteree Fock Equation with Moller Plesset second harmonic approximation. On the basis of ionisation potential charge transfer in DNA primers has been simulated with respect to sequence and length in light of design of diode, triode and transistors. This paper discusses the calculation of ionisation potentials of individual bases, charge transfer in terms of electron and hole migration. Besides design of electronic components, paper also discusses the application of these calculations in understanding DNA damage chemistry and their experimental validation.


SPIE's International Symposium on Smart Materials, Nano-, and Micro- Smart Systems | 2002

DNA-based high-density memory devices and biomolecular electronics at CSIO

Lalit M. Bharadwaj; Amol P. Bhondekar; A. K. Shukla; Vijayender Bhalla; Ram P. Bajpai

During the last half century the electronic components and computers have grown more and more powerful with the shrinking dimensions of transistors which is approaching 100nm with about a billion tiny devices working together on a single processor. The laws of quantum mechanics and limitations of materials and fabrication techniques restrict further reduction below 100nm. The most promising area is Biomolecular Electronics concerning design and fabrication of basic electronic components using biomolecules. Various organic polymers are being studied for visualization of individual molecular electronic wires and diode switches but we see enormous potential in use of DNA for such devices due to its inherent characteristics. This is because DNA can act as insulator semiconductor, conductor or superconductor depending upon the base sequence, length and orientation. The DNA can be coated selectively with metals with molecular level precision giving us capability to design molecular electronic components, such as, diode, triode, transistor, etc. This paper discusses the DNA based language developed by our group for coding and decoding any digital information in terms of DNA sequence. Basic arithmetical operations, such as, addition subtraction, multiplication, division and exponential have been defined in terms of DNA sequence and their validity has been demonstrated. Paper will also discuss our programme on study of DNA electrical behaviour in terms of sequence; length and orientation for development of biomolecular electronic components and for understanding DNA damaged chemistry.


Dry Etch Technology | 1992

Chemically assisted ion beam etching of GaAs and GaSb using reactive flux of iodine and Ar+ beam

Lalit M. Bharadwaj; Pierre Bonhomme; Joël Faure; G. Balossier; Ram P. Bajpai

The paper discusses a Chemically Assisted Ion Beam Etching (CAIBE) technique for etching of GaAs and GaSb based on reactive flux of iodine vapours derived from elemental iodine and Ar+ ion beam. The effect of iodine partial pressure in the range 0-14x10-5 torr has been studied on the etch rate of GaAs and GaSb at three different ion beam current densities. Initially, the etch rate increases with increase in iodine partial pressure; but at higher iodine flux the etch rate tends to attain saturation value. The Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) results show that uniform etching is obtained but at higher current density and high iodine flux etch pits start appearing. The high resolution electron microscopy (HREM) and electron diffraction studies show that no crystalline defects are introduced during Ar+/I2 CAIBE. The energy despersive analysis (EDS) of etched surface does not show presence of iodine. Thus the technique gives higher etch rate in comparison to only Ar+ ion beam without any art effect in terms of crystalline structure or surface contamination. The technique has been successfully used for anisotropic etching of 1.5 um test patterns using Dynachem OFPR-800 positive resit and for preparation of TEM specimen. The results on GaAs and GaSb are compared with those of Si, InP and InSb etching using Ar+/I2 CAIBE. A possible etch mechanism has been proposed to explain the etch behaviour.

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Lalit M. Bharadwaj

Central Scientific Instruments Organisation

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Nathai Ram

Central Scientific Instruments Organisation

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Sandeep Kumar

Central Scientific Instruments Organisation

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C. Ghanshyam

Central Scientific Instruments Organisation

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Sunita Mishra

Council of Scientific and Industrial Research

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A.K. Paul

Central Scientific Instruments Organisation

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A.K. Dimri

Central Scientific Instruments Organisation

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Subhash C. Jain

Council of Scientific and Industrial Research

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Vandana Mishra

Council of Scientific and Industrial Research

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Amol P. Bhondekar

Central Scientific Instruments Organisation

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