There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Nanotechnology and biosensors

Pull-in instability as an inherently nonlinear and crucial effect continues to become increasingly important for the design of electrostatic MEMS and NEMS devices and ever more interesting scientifically. This review reports not only the overview of the pull-in phenomenon in electrostatically actuated MEMS and NEMS devices, but also the physical principles that have enabled fundamental insights into the pull-in instability as well as pull-in induced failures. Pull-in governing equations and conditions to characterize and predict the static, dynamic and resonant pull-in behaviors are summarized. Specifically, we have described and discussed on various state-of-the-art approaches for extending the travel range, controlling the pull-in instability and further enhancing the performance of MEMS and NEMS devices with electrostatic actuation and sensing. A number of recent activities and achievements methods for control of torsional electrostatic micromirrors are introduced. The on-going development in pull-in applications that are being used to develop a fundamental understanding of pull-in instability from negative to positive influences is included and highlighted. Future research trends and challenges are further outlined.

Electrostatic pull-in instability in MEMS/NEMS: A review

Textbook of biochemistry with clinical correlations , 4th edn TM Devlin, ed pp xvii + 1186, illustrated Wiley-Liss, New York, 1997 £2995, hardback

This beautifully illustrated and well-written book, with an impressive array of authors, is aimed at both undergraduate and postgraduate level As the editor states in the preface, it is not intended to be a compendium of biochemistry but rather emphasises the biochemistry of mammalian cells The first 22 chapters cover …

Textbook of biochemistry with clinical correlations

https://jcp.bmj.com/content/jclinpath/12/2/193.1.full.pdf

Practical Clinical Biochemistry

Investigations of the effect of nonexponential distribution of gap states on photoconductivity

This paper describes the technique of improving the sensitivity of bulk micromachined silicon pressure sensors with judicious use of porous silicon (PS) and porous polysilicon (PPS). Since PS has a much lower Young's modulus than Si, pressure sensors with Si/PS composite membranes show higher sensitivity. The sensitivity also increases as the porosity of the PS layer increases. Further improvement in sensitivity can be achieved by replacing the conventional polysilicon piezoresistors with porous polysilicon ones. Though the composite membranes exhibit higher sensitivity, they suffer from higher offset voltage due to the stress developed by the formation of porous silicon. Pressure sensors with silicon membrane and porous polysilicon piezoresistors yield modest improvement in sensitivity without increase in offset voltage. A combination of porous polysilicon piezoresistors and composite membranes with microporous silicon gave the highest sensitivity value as well as the highest offset. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Porous silicon/polysilicon for improved sensitivity pressure sensors

Search for thermal metastability in chalcogenide glasses.

Micromolar levels of urea [1–20 mM] on surface micromachined polysilicon cantilever beams immobilized with the enzyme urease was studied. Urea hydrolyses to ammonia and carbon dioxide which are volatile in nature. Monitoring the change in resonance frequency of a urease immobilized cantilever beam during the course of urea hydrolysis, mediated by the immobilized enzyme can give us information on the reaction rates. The change in the resonance frequency of the cantilever beams as a result of urea hydrolysis was measured using Doppler Vibrometry. The reaction kinetics of the enzyme urease was studied by analyzing the dynamic response of the enzyme immobilized microcantilevers for various concentrations of urea.

Dynamic response of polysilicon microcantilevers to enzymatic hydrolysis of urea

In this letter we investigate the difference between the bond breaking and the charge trapping model of the light‐induced effect in amorphous hydrogenated silicon (a‐Si:H). We also report the partial recovery from the light‐induced effect in p‐i‐n solar cells by infrared illumination in the presence of an electric field.

Enakshi Bhattacharya

Papers

Investigations of the effect of nonexponential distribution of gap states on photoconductivity

Porous silicon/polysilicon for improved sensitivity pressure sensors

Search for thermal metastability in chalcogenide glasses.

Dynamic response of polysilicon microcantilevers to enzymatic hydrolysis of urea

Electric field and infrared‐induced recovery of metastability in amorphous hydrogenated silicon