scholarly journals APPLICATION OF nonPLANAR MICROSTRIP MICROWAVE STRUCTURES FOR gauging the DIELECTRIC PARAMETERS OF LIQUIDS AND SOLID MATERIALS

2021 ◽  
pp. 56-61
Author(s):  
Т.М. Ишкаев ◽  
А.Р. Насыбуллин ◽  
Р.В. Фархутдинов ◽  
Р.Р. Самигуллин
Keyword(s):  
Computer Modeling ◽  
Microstrip Line ◽  
High Sensitivity ◽  
Practical Implementation ◽  
Solid Materials ◽  
Dielectric Parameters ◽  
Linear Dimensions ◽  
Microwave Structures ◽  
Microwave Sensors

В данной статье отражаются основные результаты компьютерного моделирования, практической реализации и применения непланарной микрополосковой периодической СВЧ структуры в качестве преобразовательного элемента в задачах контроля диэлектрических параметров материалов и веществ. Основными достоинствами подобной реализации датчика являются большая чувствительность и относительно небольшие линейные размеры по сравнению с аналогичными, реализованными на основе планарных СВЧ структур. Помимо этого, благодаря непланарной форме микрополосковой линии расширяется диапазон областей применения СВЧ датчиков. This article reflects the main results of computer modeling, practical implementation and application of a nonplanar microstrip periodic microwave structure as transducer in the problems of gauging the dielectric parameters of materials and substances. The main advantages of such a sensor implementation are high sensitivity and relatively small linear dimensions in comparison with similar ones based on planar microwave structures. In addition, due to the nonplanar shape of the microstrip line, the range of applications for microwave sensors is expanded.

Differential Surface Plasmon Resonance Sensor for the Detection of Chemicals and Biochemicals

2013 ◽  
Vol 543 ◽  
pp. 310-313 ◽  
Author(s):  
Carmelo Fallauto ◽  
Guido Perrone ◽  
Alberto Vallan
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
High Sensitivity ◽  
Practical Implementation ◽  
Resonance Sensor ◽  
Order Of Magnitude ◽  
Long Term Monitoring ◽  
Term Monitoring

Surface plasmon resonance is one the most common optical sensing techniques for the detection of chemicals and biochemicals, although still mainly confined to lab applications. Typically, these sensors are made by a thin gold layer deposited on a glass prism or on an optical fiber similar to those used in telecom applications. Key advantages of this technique are the possibility to specifically detect different chemicals through functionalization of the metal surface and the high sensitivity, although the latter may turn into a weakness in long term monitoring applications due to cross-sensitivity to parasitic effects. To overcome this limitation the paper proposes a novel sensor implementation with a cascaded double sensing area, particularly suited for long term monitoring of pollutant since one sensing area is actually used to detect the desired molecules, while the other for compensating drifts due to fluctuations, misalignments and temperature variations. The paper addresses mainly the prism-based implementation, but the proposed configuration is suited also for an all-fiber approach. Examples of practical implementation of the proposed techniques are given, evidencing an accuracy improvement of more than an order of magnitude.

scholarly journals Modeling of magnetoelectric microwave devices

2017 ◽  
Vol 30 (3) ◽  
pp. 285-293 ◽  
Author(s):  
Alexander Tatarenko ◽  
Darya Snisarenko ◽  
Mirza Bichurin
Keyword(s):  
Computer Modeling ◽  
Microstrip Line ◽  
Coplanar Waveguide ◽  
Microwave Devices ◽  
Slot Line ◽  
Piezoelectric Structure ◽  
Insertion Losses

The possibility of computer modeling implementation of electrically controlled magnetoelectric (ME) microwave devices is considered. The computer modeling results of different structures of ME microwave devices based on layered ferrite-piezoelectric structure formed on the slot line, microstrip line and coplanar waveguide are offered. Results are reported as frequency dependencies of insertion losses of ME devices.

scholarly journals mRNA technology as one of the promising platforms for the SARS-CoV-2 vaccine development

2020 ◽  
Vol 24 (7) ◽  
pp. 802-807
Author(s):  
A. A. Ilyichev ◽  
L. A. Orlova ◽  
S. V. Sharabrin ◽  
L. I. Karpenko
Keyword(s):  
Recombinant Proteins ◽  
Messenger Rna ◽  
Viral Vectors ◽  
Vaccine Development ◽  
Dna Vaccines ◽  
High Sensitivity ◽  
Practical Implementation ◽  
Process Technology ◽  
Infected People

After the genome sequence of SARS-CoV-2 (Severe acute respiratory syndrome-related coronavirus 2) was published and the number of infected people began to increase rapidly, many global companies began to develop a vaccine. Almost all known approaches to vaccine design were applied for this purpose, including inactivated viruses, mRNA and DNA-vaccines, vaccines based on various viral vectors, synthetically generated peptides and recombinant proteins produced in cells of insects and mammals. This review considers one of the promising vaccine platforms based on messenger RNA. Until recent years, mRNA-vaccination was out of practical implementation due to high sensitivity to nuclease degradation and consequent instability of drugs based on mRNA. Latest technological advances significantly mitigated the problems of low immunogenicity, instability, and difficulties in RNA-vaccine delivery. It is worth noting that mRNA-vaccines can efficiently activate both components of the immune system, i. e. T-cell and humoral responses. The essential advantage of mRNA-vaccines includes fast, inexpensive, scalable and uniform production providing a large output of desirable products in vitro. Synthesis and purification processes significantly simplify the process technology of mRNA drugs with injectable purity. Thus, mRNA production via in vitro transcription is more advantageous as compared with DNA-vaccines since it is a chemical process without the use of cells. mRNA techniques make it possible to pass all the phases of vaccine development much faster in comparison with the production of vaccines based on inactivated viruses or recombinant proteins. This property is critically important when designing vaccines against viral pathogens as the main problem of disease control includes a time gap between an epidemic and vaccine development. This paper discusses studies on the development of vaccines against coronaviruses including SARS-CoV-2 with special attention to the mRNA technique.

scholarly journals Means for monitoring the dielectric parameters of liquid media based on quasiperiodic Bragg microwave structures in a coaxial waveguide

2020 ◽  
Vol 1499 ◽  
pp. 012015
Author(s):  
A R Nasybullin ◽  
O G Morozov ◽  
G A Morozov ◽  
R V Farkhutdinov ◽  
P V Gavrilov ◽  
...  
Keyword(s):  
Coaxial Waveguide ◽  
Liquid Media ◽  
Dielectric Parameters ◽  
Microwave Structures

scholarly journals Microfluidic Sensor Based on Composite Left-Right Handed Transmission Line

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1475 ◽  
Author(s):  
Vasa Radonić ◽  
Slobodan Birgermajer ◽  
Ivana Podunavac ◽  
Mila Djisalov ◽  
Ivana Gadjanski ◽  
...  
Keyword(s):  
Phase Shift ◽  
Transmission Lines ◽  
Electromagnetic Waves ◽  
Microstrip Line ◽  
Effective Permittivity ◽  
Ground Plane ◽  
High Sensitivity ◽  
Biomass Estimation ◽  
Shift Measurement ◽  
The Right

In this paper, we propose a novel metamaterial-based microfluidic sensor that permits the monitoring of properties of the fluid flowing in the microfluidic reservoir embedded between the composite left–right handed (CLRH) microstrip line and the ground plane. The sensor’s working principle is based on the phase shift measurement of the two signals, the referent one that is guided through conventional microstrip line and measurement signal guided through the CLRH line. At the operating frequency of 1.275 GHz, the CLRH line supports electromagnetic waves with group and phase velocities that are antiparallel, and therefore the phase “advance” occurs in the case of CLRH line, while phase delay arises in the right-handed (RH) frequency band. The change of the fluid’s properties that flow in the microfluidic reservoir causes the change of effective permittivity of the microstrip substrate, and subsequently the phase velocity changes, as well as the phase shift. This effect was used in the design of the microfluidic sensor for the measurement of characteristics of the fluid that flows in the microfluidic reservoir placed under the CLRH line. The complete measurement system was developed including the Wilkinson power divider that splits the signal between conventional RH and CLRH section, transmission lines with the microfluidic reservoirs, and a detection circuit for phase shift measurement. Measurement results for different fluids confirm that the proposed sensor is characterized by relatively high sensitivity and good linearity (R2 = 0.94). In this study, the practical application of the proposed sensor is demonstrated for the biomass estimation inside the microfluidic bioreactors, which are used for the cultivation of MRC-5 fibroblasts.

scholarly journals NEW WAVEGUIDE METHOD FOR DIELECTRIC PARAMETER MEASUREMENT

2018 ◽  
pp. 33-38
Author(s):  
Andrey D. Grigoriev
Keyword(s):  
Frequency Band ◽  
Loss Tangent ◽  
Measurement Techniques ◽  
Microwave Frequency ◽  
Reflection Factor ◽  
Dielectric Parameter ◽  
Practical Implementation ◽  
Dielectric Parameters ◽  
Waveguide Section ◽  
Noise Component

Perfect knowledge of dielectric parameters is necessary for its application in various devices. In spite of the whole range of measurement techniques, their practical implementation in the microwave frequency band runs into some difficulties. This article describes a new method for nonmagnetic dielectrics permittivity and loss tangent measurement in the microwave frequency band. A dielectric specimen slab is placed in the short-circuited waveguide section normal to its axis and fills the whole cross-section of the waveguide at approximately quarter wavelength from its short-circuited endpoint. By means of the vector network analyzer the waveguide section reflection factor is measured. Objective function is de-termined as difference between calculated and measured module and phase of the reflection factor. Specific code for ob-jective function calculation and its minimization is worked out. Minimization of this function by varying dielectric parameters makes it possible to find real values of these parameters. The method needs no de-embedding and can be used with non-calibrated waveguide-to-coax transitions. Also it is less sensitive to the noise component of reflected signal. The testing results show that new method’s error does not exceed 0.2 % for relative permittivity and 1% for dielectric loss tangent.

scholarly journals Vertically Coupled Plasmonic Racetrack Ring Resonator for Biosensor Applications

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 203 ◽  
Author(s):  
Kirill V. Voronin ◽  
Yury V. Stebunov ◽  
Artem A. Voronov ◽  
Aleksey V. Arsenin ◽  
Valentyn S. Volkov
Keyword(s):  
Refractive Index ◽  
Ring Resonator ◽  
High Sensitivity ◽  
Light Transmittance ◽  
Practical Implementation ◽  
Refractive Index Sensor ◽  
Plasmonic Waveguides ◽  
Optical Elements ◽  
A Value ◽  
Strip Waveguide

Plasmonic chemical and biological sensors offer significant advantages such as really compact sizes and extremely high sensitivity. Biosensors based on plasmonic waveguides and resonators are some of the most attractive candidates for mobile and wearable devices. However, high losses in the metal and complicated schemes for practical implementation make it challenging to find the optimal configuration of a compact plasmon biosensor. Here, we propose a novel plasmonic refractive index sensor based on a metal strip waveguide placed under a waveguide-based racetrack ring resonator made of the same metal. This scheme guarantees effective coupling between the waveguide and resonator and low loss light transmittance through the long-range waveguide. The proposed device can be easily fabricated (e.g., using optical lithography) and integrated with materials like graphene oxide for providing adsorption of the biomolecules on the sensitive part of the optical elements. To analyze the properties of the designed sensing system, we performed numerical simulations along with some analytical estimations. There is one other interesting general feature of this sensing scheme that is worth pointing out before looking at its details. The sensitivity of the considered device can be significantly increased by surrounding the resonator with media of slightly different refractive indices, which allows sensitivity to reach a value of more than 1 μm per refractive index unit.

scholarly journals Paediatric Diagnostic Reference levels in low Resource Settings: A Guide for Developing Country Practitioners with excerpts from ICRP

2020 ◽  
Vol 34 (1) ◽  
pp. 37-41
Author(s):  
Flavious Nkubli ◽  
Christian Nzotta ◽  
Chigozie Nwobi ◽  
Joseph Dlama
Keyword(s):  
Medical Imaging ◽  
Imaging Modality ◽  
High Sensitivity ◽  
Reference Level ◽  
Practical Implementation ◽  
Diagnostic Reference Levels ◽  
Reference Levels ◽  
Imaging Protocol ◽  
Body Sizes ◽  
Paediatric Imaging

Background: The practical implementation of Diagnostic Reference Level in paediatric imaging is a complex task due to their unique individuality in terms of high sensitivity to radiation, varying body sizes and presenting pathology. Hence, good knowledge of medical technology, skill to perform patient dosimetry and to analyze mage quality is required. Purpose: To provide a guide on the methodological requirements for the establishment of Paediatric Diagnostic Reference Levels (PiDRLs) based on the revised and updated guidelines from the current ICRP publication 135 on Diagnostic Reference Levels (DRLs). Materials and method: An extensive review of the ICRP report Publication 135 on Diagnostic Reference levels in medical imaging with a focus on paediatric imaging and other related studies were undertaken. Results: The ICRP report 135 updates and refines the recommendations of 2001. It highlights that the application of DRLs in paediatrics alone is not sufficient for the optimization of protection. Image quality must be evaluated. Quantities used for DRLs should be appropriate to the imaging modality being evaluated, assess the amount of ionizing radiation applied to perform a medical imaging task, and be measured directly. For interventional procedures, the complexity of the procedure may be considered in setting DRLs. DRLs shall not be used for individual patients or as trigger (alert or alarm) levels for individual patients. Appropriate weight bands (generally with 5 or 10 kg intervals) are recommended for establishing paediatric DRLs and should be promoted. Conclusion: The amount of radiation used for examinations of children can vary tremendously due to great variation in patient size and weight from neonates to adult-sized adolescents. This variation in patient radiation dose is appropriate. However, variation in patient doses due to inappropriate technique or failure to child-size the imaging protocol is not appropriate. This forms the basis of the new ICRP guideline and should form the basis of developing PiDRLs.

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