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

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

https://www.uta.edu/rfmems/GI_Sensor/papers/ac040049d.pdf

Fiber-Optic Chemical Sensors and Biosensors

Today cross-cutting approaches, where molecular engineering and clever processing are synergistically coupled, allow the chemist to tailor complex hybrid systems of various shapes with perfect mastery at different size scales, composition, functionality, and morphology. Hybrid materials with organic–inorganic or bio–inorganic character represent not only a new field of basic research but also, via their remarkable new properties and multifunctional nature, hybrids offer prospects for many new applications in extremely diverse fields. The description and discussion of the major applications of hybrid inorganic–organic (or biologic) materials are the major topic of this critical review. Indeed, today the very large set of accessible hybrid materials span a wide spectrum of properties which yield the emergence of innovative industrial applications in various domains such as optics, micro-electronics, transportation, health, energy, housing, and the environment among others (526 references).

Applications of advanced hybrid organic–inorganic nanomaterials: from laboratory to market

An increase in world population along with a significant aging portion is forcing rapid rises in healthcare costs. The healthcare system is going through a transformation in which continuous monitoring of inhabitants is possible even without hospitalization. The advancement of sensing technologies, embedded systems, wireless communication technologies, nano technologies, and miniaturization makes it possible to develop smart systems to monitor activities of human beings continuously. Wearable sensors detect abnormal and/or unforeseen situations by monitoring physiological parameters along with other symptoms. Therefore, necessary help can be provided in times of dire need. This paper reviews the latest reported systems on activity monitoring of humans based on wearable sensors and issues to be addressed to tackle the challenges.

Wearable Sensors for Human Activity Monitoring: A Review

This contribution presents a pH sensor based on the combination of two technologies: tapered standard-single mode optical fiber (S-SMF) and an electromagnetic resonance phenomenon called Lossy Mode Resonance (LMR). This last phenomenon is produced by coating the optical structure with a thin polymeric film, which for specific values of the coating refractive index and thickness causes a maximum coupling of light guided in the tapered S-SMF region. Layer-by-layer electrostatic self assembly technique was used for the fabrication of a polymeric sensing nanostructure. The construction process was optimized in order to visualize the LMR behavior with a device length of 5 mm. The sensing combination produces a 250 nm wavelength-shift and a 20 dB attenuation variation of the LMR when varying the pH from 4 to 6.

Lossy Mode Resonance-based pH sensor using a tapered single mode optical fiber coated with a polymeric nanostructure

In this work, lossy mode resonance (LMR) based optical fiber refractometers are fabricated by using a transparent
coating (indium oxide), as the LMR supporting layer. The utilization of indium oxide coatings permits the fabrication of
highly sensitive optical fiber refractometers and enables the tunability of the LMR by adjusting the fabrication
parameters, such as the coating thickness. The detection technique is based on the wavelength shift of the LMR. In this
work it has been studied the influence of the external refractive index, achieving a maximum sensitivity of 2.24e-4
refractive index units per nanometer. Moreover, by adequated parameterization, more than one LMR can be observed in
the wavelength range analyzed in the experiments, which leads to a more accurate measurement of the refractive index.

Lossy-mode resonance-based refractometers by means of indium oxide coatings fabricated onto optical fibers

In this work, the fabrication and characterization of a small and portable exhaled breath sensor based on Lossy Mode Resonances (LMR) is presented. Tin oxide (SnO2) coatings fabricated onto optical fibers are used as LMR supporting coatings. The principle of operation is based on the measurement of refractive index changes by the LMR device (with an average sensitivity of 8355 nm/RIU) originated by the condensation of micro water droplets in the surroundings of the SnO2 coating during the breath natural process. The sensor shows a repetitive response with less than 100 ms of response time and a wavelength shift of 150 nm from inhalation to exhalation.

Exhaled Breath Optical Fiber Sensor based on LMRs for Respiration Monitoring

Here, we present a novel method to fabricate long period gratings using standard single mode optical fibers (SMF). These optical devices were fabricated in a three-step process, which consisted of etching the SMF, then coating it with a thin-film and, the final step, which involved removing sections of the coating periodically by laser ablation. Tin dioxide was chosen as the material for this study and it was sputtered using a pulsed DC sputtering system. Theoretical simulations were performed in order to select the appropriate parameters for the experiments. The responses of two different devices to different external refractive indices was studied, and the maximum sensitivity obtained was 6430 nm/RIU for external refractive indices ranging from 1.37 to 1.39.

Fabrication of Long Period Gratings by Periodically Removing the Coating of Cladding-Etched Single Mode Optical Fiber Towards Optical Fiber Sensor Development.

The inscription of cascaded long-period gratings of different periods in optical fiber permits us to obtain both narrowband and wideband filters in the same spectrum. If used as an optical transducer, it may permit us to detect with the same device-wide and small parameter changes. The transmission spectra have been simulated using a theoretical model based on LP mode coupling and have been also experimentally demonstrated

/pdf/generation-of-selective-fringes-with-cascaded-long-period-5aklxx5qw8.pdf

Ignacio R. Matias

Papers

Lossy Mode Resonance-based pH sensor using a tapered single mode optical fiber coated with a polymeric nanostructure

Lossy-mode resonance-based refractometers by means of indium oxide coatings fabricated onto optical fibers

Exhaled Breath Optical Fiber Sensor based on LMRs for Respiration Monitoring

Fabrication of Long Period Gratings by Periodically Removing the Coating of Cladding-Etched Single Mode Optical Fiber Towards Optical Fiber Sensor Development.

Generation of selective fringes with cascaded long-period gratings