scholarly journals Anisotropic charge trapping in phototransistors unlocks ultrasensitive polarimetry

2021 ◽  
Author(s):  
Jing Pan ◽  
Xiujuan Zhang ◽  
Yiming Wu ◽  
Jinhui Chen ◽  
Jinwen Wang ◽  
...  
Keyword(s):  
Design Principle ◽  
Charge Trapping ◽  
Linear Dichroism ◽  
Medical Diagnostics ◽  
Charge Carriers ◽  
Design Rule ◽  
Polarization Sensitivity ◽  
Current State ◽  
Celestial Compass ◽  
Gating Effect

Abstract Being able to probe the polarization states of light is crucial for applications from medical diagnostics and bio-inspired navigation to information encryption and quantum computing. Current state-of-the-art polarimeters based on anisotropic semiconductors enable direct linear dichroism photodetection without the need for bulky and complex external optics. However, their polarization sensitivity is restricted by the inherent optical anisotropy, leading to low dichroic ratios of typically smaller than ten. Here, we unveil an effective and general design rule to achieve a more than 2,000-fold enhanced polarization sensitivity by exploiting a light-induced anisotropic gating effect in organic phototransistors. The polarization-dependent trapping of photogenerated charge carriers provides an anisotropic photo-induced gate for current amplification, which has resulted in an extremely high dichroic ratio of over 1.2×104, more than two orders of magnitude higher than any previous reports. These findings further enable the first demonstration of a novel miniaturized bionic celestial compass for skylight-based polarization navigation. Our results offer a fundamental design principle and a new route for the development of next-generation highly polarization-sensitive optoelectronics.

Smart Nanodevices for Point-of-Care Applications

2021 ◽  
Vol 17 ◽  
Author(s):  
Rajasekhar Chokkareddy ◽  
Suvardhan Kanchi ◽  
Inamuddin
Keyword(s):  
Chronic Diseases ◽  
Patient Monitoring ◽  
State Of The Art ◽  
Point Of Care ◽  
Low Cost ◽  
Medical Diagnostics ◽  
Diagnostic Tools ◽  
Current State ◽  
Rural Patients ◽  
Diagnosis Of Diseases

Background: While significant strides have been made to avoid mortality during the treatment of chronic diseases, it is still one of the biggest health-care challenges that have a profound effect on humanity. The development of specific, sensitive, accurate, quick, low-cost, and easy-to-use diagnostic tools is therefore still in urgent demand. Nanodiagnostics is defined as the application of nanotechnology to medical diagnostics that can offer many unique opportunities for more successful and efficient diagnosis and treatment for infectious diseases. Methods: In this review we provide an overview of infectious disease using nanodiagnostics platforms based on nanoparticles, nanodevices for point-of-care (POC) applications. Results: Current state-of-the-art and most promising nanodiagnostics POC technologies, including miniaturized diagnostic tools, nanorobotics and drug delivery systems have been fully examined for the diagnosis of diseases. It also addresses the drawbacks, problems and potential developments of nanodiagnostics in POC applications for chronic diseases. Conclusions: While progress is gaining momentum in this field and many researchers have dedicated their time in developing new smart nanodevices for POC applications for various chronic diseases, the ultimate aim of achieving longterm, reliable and continuous patient monitoring has not yet been achieved. Moreover, the applicability of the manufactured nanodevices to rural patients for on-site diagnosis, cost, and usability are the crucial aspects that require more research, improvements, and potential testing stations. Therefore, more research is needed to develop the demonstrated smart nanodevices and upgrade their applicability to hospitals away from the laboratories.

scholarly journals Dynamics of Photogenerated Charge Carriers in TiO2/MoO3, TiO2/WO3 and TiO2/V2O5 Photocatalysts with Mosaic Structure

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1022
Author(s):  
Alexander I. Kokorin ◽  
Tatyana V. Sviridova ◽  
Elizaveta A. Konstantinova ◽  
Dmitry V. Sviridov ◽  
Detlef W. Bahnemann
Keyword(s):  
Light Exposure ◽  
Low Cost ◽  
Energy Levels ◽  
Charge Trapping ◽  
Bactericidal Effect ◽  
High Reactivity ◽  
Charge Carriers ◽  
Light Illumination ◽  
Uv Illumination ◽  
Photocatalytic Material

Titania is a widely used photocatalytic material possessing such advantages as low cost and high reactivity under the ultraviolet light illumination. However, the fast recombination of photoexcited charge carriers limits its application. Herein, we have synthesized original nanomaterials with mosaic structures that exhibited well-defined heterojunctions and new properties. Using SEM, XRD, EPR spectroscopy, photocatalytic measurements, and photoinduced pathphysiological activity of these photocatalysts, we studied the processes of charge carrier accumulation in TiO2/MoO3, TiO2/WO3, and TiO2/V2O5 under in situ UV illumination with emphasis on the charge exchange between energy levels of these nanosized semiconductors. It is shown that the accumulation of photoinduced charges occurs in two forms (i) filled electron traps corresponding to Ti4+/Ti3+ levels and (ii) Mo5+ centers, both forms contributing to the photoinduced biocide activity of the samples. This work demonstrates that light exposure of heterostructure photocatalysts with mosaic surfaces produces different types of charge-trapping centers capable of interacting with molecular oxygen yielding peroxo species, which provide long-life light-induced ”self-cleaning” behavior. Such photoaccumulating materials open new opportunities in developing light-driven self-sterilization structures exhibiting a prolonged bactericidal effect up to 10 h after stopping light exposure.

Design Potentials of External Gear Machines With Asymmetric Tooth Profile

2013 ◽  
Author(s):  
Ram Sudarsan Devendran ◽  
Andrea Vacca
Keyword(s):  
Design Principle ◽  
State Of The Art ◽  
Design Method ◽  
Optimization Procedure ◽  
Tooth Profile ◽  
Design Parameters ◽  
Simulation Tool ◽  
Performance Potentials ◽  
Current State ◽  
Very High

This paper describes the design, optimization and the performance potentials of external gear machines with asymmetric tooth profiles. Conventionally, the design of these machines is entirely based on symmetric involute profile. A design method has been developed to derive the tooth profiles based on a modified rack-cutter profile which is assumed to be used for manufacturing the gears with asymmetric involute surfaces and trochoidal fillet profiles. The study is based on the simulation tool HYGESim (HYdraulic GEar machines Simulator) which is being developed and has been validated by the authors’ research group to accurately analyze the performance of the machine. For the purpose of this research, HYGESim was adapted to simulate the particular case of non-symmetric gear profiles. A specific optimization procedure based on genetic algorithm was implemented to find the maximum performance of the new design, in terms of volumetric efficiency, fluid borne noise, internal pressure peaks and localized cavitation acting on the design parameters that characterize the tooth profile. The results of the optimization process are compared to the current state of the art for external gear machines. This comparison show very high potentials for this new design principle, particularly concerning the reduction of the fluid borne noise.

An Analysis of Modularity As a Design Rule Using Network Theory

2018 ◽  
Author(s):  
Hannah S. Walsh ◽  
Andy Dong ◽  
Irem Y. Tumer
Keyword(s):  
Network Theory ◽  
Design Principle ◽  
Network Models ◽  
Design Rule ◽  
Function Parameter ◽  
Engineering Systems ◽  
System Architectures ◽  
System Representation ◽  
And Function ◽  
Random Failures

Increasing the modularity of system architectures is generally accepted as a good design principle in engineering. In this paper, we explore whether modularity comes at the expense of robustness. To that end, we model three engineering systems as networks and measure the relation between modularity and robustness to random failures. We produced four types of network models of systems — component, component-function, component-parameter, and function-parameter — to further test the relation of robustness to the type of system representation, architectural or behavioral. The results show that higher modularity is correlated with lower robustness (p < 0.001) and that the estimated modularity of the system can depend on the type of system representation. The implication is that there is a trade-off between modularity and robustness, meaning that increasing modularity might not be appropriate for systems for which robustness is critical and for those whose modularity estimate differs largely between each type of system representation.

An Analysis of Modularity as a Design Rule Using Network Theory

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Hannah S. Walsh ◽  
Andy Dong ◽  
Irem Y. Tumer
Keyword(s):  
Network Theory ◽  
Design Principle ◽  
Network Models ◽  
Design Rule ◽  
Function Parameter ◽  
Engineering Systems ◽  
System Architectures ◽  
System Representation ◽  
And Function ◽  
Random Failures

Increasing the modularity of system architectures is generally accepted as a good design principle in engineering. In this paper, we explore whether modularity comes at the expense of robustness. To that end, we model three engineering systems as networks and measure the relation between modularity and robustness to random failures. We produced four types of network models of systems—component-component, component-function, component-parameter, and function-parameter—to further test the relation of robustness to the type of system representation, architectural or behavioral. The results show that higher modularity is correlated with lower robustness (p < 0.001) and that the estimated modularity of the system can depend on the type of system representation. The implication is that there is a tradeoff between modularity and robustness, meaning that increasing modularity might not be appropriate for systems for which robustness is critical and modularity estimates differ significantly between the types of system representation.

INTERACTIONS OF THz VIBRATIONAL MODES WITH CHARGE CARRIERS IN DNA: POLARON-PHONON INTERACTIONS

2007 ◽  
Vol 17 (02) ◽  
pp. 293-309 ◽  
Author(s):  
DINAKAR RAMADURAI ◽  
TAKAYUKI YAMANAKA ◽  
YANG LI ◽  
MILANA VASUDEV ◽  
VISWANATH SANKAR ◽  
...  
Keyword(s):  
Charge Transport ◽  
Electrical Transport ◽  
Theoretical Calculations ◽  
Charge Trapping ◽  
Directed Assembly ◽  
Charge Carriers ◽  
Vibrational Modes ◽  
Electrical Transport Properties ◽  
One Dimensional ◽  
Phonon Absorption

This paper presents models and experimental measurements that shed light on THz-phonon mediated transport of polarons in biomolecules. Polaron transport in DNA has been considered recently in view of the expected derealization of charge carriers on a one-dimensional wire as well as the highly charged nature of DNA.1,2 An understanding of the electrical transport properties and THz-phonon interactions of biomolecules is important in view of DNA's potential applications both as electrically conductive wires and as structures that facilitate the chemically-directed assembly of massively integrated ensembles of nanoscale semiconducting elements into terascale integrated networks. Moreover, understanding these interactions provides information of the THz spectrum of vibrational modes in DNA. A primary focus of this paper is on charge transport in biomolecules using indirect-bandgap colloidal nanocrystals linked with biomolecules.3 Through a combination of theoretical and experimental approaches,4-7 this paper focuses on understanding the electrical properties and THz-frequency interactions of DNA. Moreover, this paper presents observed charge transport phenomena in DNA and discusses how these measurements are related to carrier scattering from the THz vibrational modes in DNA. Indeed, carrier transport in DNA is analyzed in light of theoretical calculations of the effects of THz-frequency phonon emission by propagating carriers, THz-frequency phonon absorption by propagating and trapped carriers, and effective mass calculations for specific sequences of the DNA bases.1-7 These studies focus on THz-phonon-mediated processes since an extra carrier on a one-dimensional chain minimizes its energy by forming an extended polaron, and since many biomolecules, including DNA, exhibit THz vibrational spectra.8 Accordingly, these calculations focus on THz-phonon-mediated processes. These results are discussed in terms of the role of THz-phonon-mediated charge trapping and detrapping effects near guanine-rich regions of the DNA as well as on the understanding and identification of DNA with specific base sequences that promote charge transport. As in previous studies, optical excitation is used to inject carriers into DNA wires. Moreover, this paper reports on the use of gel electrophoresis to study charge-induced cleavage of DNA and the related transport of charge in DNA. Phonon absorption and emission from polarons in DNA,9 is analyzed using parameters from the well-known Su-Schrieffer-Heeger Hamiltonian.

scholarly journals Development of a program for diagnosing diseases by the test recognition method

2020 ◽  
Vol 7 (3) ◽  
Author(s):  
Kseniya Reznikova ◽  
Denis Savchenko ◽  
Anna Smyshlyaeva
Keyword(s):  
Pattern Recognition ◽  
Programming Language ◽  
Human Factor ◽  
Medical Diagnostics ◽  
Recognition Method ◽  
Advantages And Disadvantages ◽  
Current State ◽  
Test Algorithm ◽  
High Level ◽  
Diagnosis Of Diseases

Theory of pattern recognition is an important theoretical and applied area in computer science. Depending on the nature of the task for recognition are used different approaches. In this article the authors investigate the current state of the use of supercomputers in the field of medical diagnostics and propose an affordable applied solution for diagnosing diseases based on the use of test recognition. Test recognition is based on such a combinatorial-logical approach as a test algorithm. Test algorithms are based on the analysis of a set of deadlock table tests and depend on the dimension of a given matrix of objects and their features. A deadlock test is an incompressible set of features that contains all the information about dividing a table into classes. In this work briefly presents the chronology of the development of test algorithms for solving recognition problems. The authors have developed an interpretation of the test algorithm to automate the diagnosis of diseases by identifying the proximity of the desired subset (available symptoms) to one of the existing ones (diagnoses) by defining deadlock tests. In addition to the presented algorithm, screenshots are presented with an example of a step-by-step solution in the form of a console application created in the high-level programming language C#. On the basis of the developed algorithm, the authors propose an example of a ready-made software solution in the form of a window application for diagnosing diseases based on the patient's symptoms. The developed software solution allows to mark the patient's symptoms and automatically calculate the most probable disease. The program narrows the range of acceptable values (diagnoses) depending on the symptoms marked by the user and provides an assessment of possible diseases, helping the doctor in making a diagnosis and minimizing errors made by the human factor. The article provides an assessment of the advantages and disadvantages of the developed solution, considers other areas of application of test recognition

scholarly journals Механизмы влияния терагерцового излучения на клетки (обзор)

2020 ◽  
Vol 128 (6) ◽  
pp. 852
Author(s):  
О.П. Черкасова ◽  
Д.С. Сердюков ◽  
А.С. Ратушняк ◽  
Е.Ф. Немова ◽  
Е.Н. Козлов ◽  
...  
Keyword(s):  
Biological Activity ◽  
Human Body ◽  
Science And Technology ◽  
Medical Diagnostics ◽  
Thz Radiation ◽  
Current State ◽  
State Of Research ◽  
Diagnostics And Therapy ◽  
Thz Waves

Terahertz (THz) radiation and related technologies are rapidly developed and find their application in different branches of science and technology, including medical diagnostics and therapy. This poses a problem of determining the safety limits of the human body exposure to THz radiation, which is closely related to a problem of biological activity of THz waves. Therefore, in this work, the current state of research in the area of THz radiation – cells interaction is overviewed.

Bioinspired dual-morphing stretchable origami

2019 ◽  
Vol 4 (36) ◽  
pp. eaay3493 ◽  
Author(s):  
Woongbae Kim ◽  
Junghwan Byun ◽  
Jae-Kyeong Kim ◽  
Woo-Young Choi ◽  
Kirsten Jakobsen ◽  
...  
Keyword(s):  
Design Principle ◽  
Large Range ◽  
Fluid Pressure ◽  
Single Mode ◽  
Whole Body ◽  
Design Rule ◽  
Dual Mode ◽  
Shape Morphing ◽  
Skin Stretching ◽  
Unit Cells

Nature demonstrates adaptive and extreme shape morphing via unique patterns of movement. Many of them have been explained by monolithic shape-changing mechanisms, such as chemical swelling, skin stretching, origami/kirigami morphing, or geometric eversion, that were successfully mimicked in artificial analogs. However, there still remains an unexplored regime of natural morphing that cannot be reproduced in artificial systems by a “single-mode” morphing mechanism. One example is the “dual-mode” morphing of Eurypharynx pelecanoides (commonly known as the pelican eel), which first unfolds and then inflates its mouth to maximize the probability of engulfing the prey. Here, we introduce pelican eel–inspired dual-morphing architectures that embody quasi-sequential behaviors of origami unfolding and skin stretching in response to fluid pressure. In the proposed system, fluid paths were enclosed and guided by a set of entirely stretchable origami units that imitate the morphing principle of the pelican eel’s stretchable and foldable frames. This geometric and elastomeric design of fluid networks, in which fluid pressure acts in the direction that the whole body deploys first, resulted in a quasi-sequential dual-morphing response. To verify the effectiveness of our design rule, we built an artificial creature mimicking a pelican eel and reproduced biomimetic dual-morphing behavior. By compositing the basic dual-morphing unit cells into conventional origami frames, we demonstrated architectures of soft machines that exhibit deployment-combined adaptive gripping, crawling, and large range of underwater motion. This design principle may provide guidance for designing bioinspired, adaptive, and extreme shape-morphing systems.

Gold nanoparticle charge trapping and relation to organic polymer memory devices

2009 ◽  
Vol 367 (1905) ◽  
pp. 4215-4225 ◽  
Author(s):  
D. Prime ◽  
S. Paul ◽  
P. W. Josephs-Franks
Keyword(s):  
Gold Nanoparticles ◽  
Charge Trapping ◽  
Organic Polymer ◽  
Memory Devices ◽  
Metal Insulator ◽  
Current State ◽  
Device Structures ◽  
Low Costs ◽  
Silicon Based ◽  
Polymer Memory

Nanoparticle-based polymer memory devices (PMDs) are a promising technology that could replace conventional silicon-based electronic memory, offering fast operating speeds, simple device structures and low costs. Here we report on the current state of nanoparticle PMDs and review some of the problems that are still present in the field. We also present new data regarding the charging of gold nanoparticles in metal–insulator–semiconductor capacitors, showing that charging is possible under the application of an electric field with a trapped charge density due to the nanoparticles of 3.3×10 12  cm −2 .

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