scholarly journals A Biaxial Strain Sensor Using a Single MoS2 Grating

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Junxiang Xiang ◽  
Wenhui Wang ◽  
Lantian Feng ◽  
Chao Feng ◽  
Meng Huang ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Strain Sensor ◽  
Grating Period ◽  
Strain Component ◽  
Biaxial Strain ◽  
New Approach ◽  
Additional Strain ◽  
New Type ◽  
Diffraction Patterns ◽  
Single Crystal Layer

AbstractIn this paper, we report a new type of MoS2-based grating sensor for in-plane biaxial strain gauges with a precision limit of ~ 1‰. The MoS2 grating is numerically simulated with different biaxial strains up to 5%. Our first-principles calculations reveal that the strain sensitivity of the MoS2 reflectance spectrum can be considered an additional strain sensor integrated with the grating structure, enabling the mapping of in-plane biaxial strains. Our experimental studies on a prototype MoS2-grating sensor further confirm that a strain component perpendicular to the grating period can cause intensity peak shifts in the grating’s first-order diffraction patterns. This work opens a new path towards the sensing of in-plane biaxial strain within a single-grating device. Our new approach is applicable for other materials that have predictable reflectance response under biaxial strains and the capacity to form a two-dimensional single-crystal layer.

Automatic analysis of Kikuchi diffraction patterns

1994 ◽  
Vol 52 ◽  
pp. 900-901
Author(s):  
H. Weiland ◽  
D. P. Field
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Spatial Resolution ◽  
Relevant Information ◽  
Crystalline Materials ◽  
Large Size ◽  
Transmission Electron ◽  
New Type ◽  
Diffraction Patterns ◽  
Orientation Determination

Recent advances in the automatic indexing of backscatter Kikuchi diffraction patterns on the scanning electron microscope (SEM) has resulted in the development of a new type of microscopy. The ability to obtain statistically relevant information on the spatial distribution of crystallite orientations is giving rise to new insight into polycrystalline microstructures and their relation to materials properties. A limitation of the technique in the SEM is that the spatial resolution of the measurement is restricted by the relatively large size of the electron beam in relation to various microstructural features. Typically the spatial resolution in the SEM is limited to about half a micron or greater. Heavily worked structures exhibit microstructural features much finer than this and require resolution on the order of nanometers for accurate characterization. Transmission electron microscope (TEM) techniques offer sufficient resolution to investigate heavily worked crystalline materials.Crystal lattice orientation determination from Kikuchi diffraction patterns in the TEM (Figure 1) requires knowledge of the relative positions of at least three non-parallel Kikuchi line pairs in relation to the crystallite and the electron beam.

scholarly journals Cryogenic Exfoliation of 2D Stanene Nanosheets for Cancer Theranostics

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Jiang Ouyang ◽  
Ling Zhang ◽  
Leijiao Li ◽  
Wei Chen ◽  
Zhongmin Tang ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Density Functional ◽  
Biomedical Application ◽  
Density Functional Theory Calculations ◽  
Free Electrons ◽  
Functional Theory ◽  
New Approach ◽  
New Type ◽  
Average Size ◽  
Cancer Theranostics

Abstract Stanene (Sn)-based materials have been extensively applied in industrial production and daily life, but their potential biomedical application remains largely unexplored, which is due to the absence of the appropriate and effective methods for fabricating Sn-based biomaterials. Herein, we explored a new approach combining cryogenic exfoliation and liquid-phase exfoliation to successfully manufacture two-dimensional (2D) Sn nanosheets (SnNSs). The obtained SnNSs exhibited a typical sheet-like structure with an average size of ~ 100 nm and a thickness of ~ 5.1 nm. After PEGylation, the resulting PEGylated SnNSs (SnNSs@PEG) exhibited good stability, superior biocompatibility, and excellent photothermal performance, which could serve as robust photothermal agents for multi-modal imaging (fluorescence/photoacoustic/photothermal imaging)-guided photothermal elimination of cancer. Furthermore, we also used first-principles density functional theory calculations to investigate the photothermal mechanism of SnNSs, revealing that the free electrons in upper and lower layers of SnNSs contribute to the conversion of the photo to thermal. This work not only introduces a new approach to fabricate 2D SnNSs but also establishes the SnNSs-based nanomedicines for photonic cancer theranostics. This new type of SnNSs with great potential in the field of nanomedicines may spur a wave of developing Sn-based biological materials to benefit biomedical applications.

scholarly journals Collective Losses of Low Power Cage Induction Motors—A New Approach

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1749
Author(s):  
Elzbieta Szychta ◽  
Leszek Szychta
Keyword(s):  
Control System ◽  
Experimental Studies ◽  
Complex Problem ◽  
Accurate Estimation ◽  
New Approach ◽  
Water Pumping ◽  
Efficiency Control ◽  
Interacting Systems ◽  
Cage Induction Motor ◽  
Selection Of

Energy efficiency of systems of water pumping is a complex problem since efficiency of two distinct interacting systems needs to be combined: water and power supply. This paper introduces a non-intrusive method of calculating the so-called “collective losses” of a cage induction motor. The term “collective losses”, which the authors define, allows for accurate estimation of motor efficiency. Control system of a pump determines operating point of a pumping station, and thus its efficiency. General estimated performance characteristics of a motor, components of a control system, are assumed to serve selection of a range of pumping speed variations. Rotational speed has a direct effect on motor load torque, pump power and head, and thus on motor performance. Hellwig’s statistical method was used to specify characteristics of estimated collective losses on the basis of experimental studies of 21 motors rated at up to 2.2 kW. The results of simulations and experiments are used to verify validity and efficiency of the suggested method. The method is non-intrusive, simple to use, and requires minimum data.

scholarly journals Acousto-Optic Cells with Phased-Array Transducers and Their Application in Systems of Optical Information Processing

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 451
Author(s):  
Vladimir Balakshy ◽  
Maxim Kupreychik ◽  
Sergey Mantsevich ◽  
Vladimir Molchanov
Keyword(s):  
Phased Array ◽  
Power Conversion ◽  
Experimental Studies ◽  
Acoustic Power ◽  
Acoustic Mode ◽  
Bragg Angle ◽  
Excitation Band ◽  
Acousto Optic Interaction ◽  
Array Transducer ◽  
New Type

This paper presents the results of theoretical and experimental studies of anisotropic acousto-optic interaction in a spatially periodical acoustic field created by a phased-array transducer with antiphase excitation of adjacent sections. In this case, contrary to the nonsectioned transducer, light diffraction is absent when the optical beam falls on the phased-array cell at the Bragg angle. However, the diffraction takes place at some other angles (called “optimal” here), which are situated on the opposite sides to the Bragg angle. Our calculations show that the diffraction efficiency can reach 100% at these optimal angles in spite of a noticeable acousto-optic phase mismatch. This kind of acousto-optic interaction possesses a number of interesting regularities which can be useful for designing acousto-optic devices of a new type. Our experiments were performed with a paratellurite (TeO2) cell in which a shear acoustic mode was excited at a 9∘ angle to the crystal plane (001). The piezoelectric transducer had to nine antiphase sections. The efficiency of electric to acoustic power conversion was 99% at the maximum frequency response, and the ultrasound excitation band extended from 70 to 160 MHz. The experiments have confirmed basic results of the theoretical analysis.

scholarly journals Falling weight impact test of a new-type flexible rock-shed

2018 ◽  
Vol 38 (2) ◽  
pp. 242-252
Author(s):  
Jianrong Yang ◽  
Zhiyu Zhang
Keyword(s):  
Experimental Studies ◽  
Steel Tube ◽  
Time Interval ◽  
Explicit Finite Element ◽  
Numerical Studies ◽  
Structural Details ◽  
Tensile Forces ◽  
New Type ◽  
Falling Weight ◽  
The Impact

A new concept of a flexible rock-shed is presented for protection of the railway from falling rocks. The flexible rock-shed is made of flexible nets connected by specific spring spacer bars to an array of reinforced concrete portable frames which are linked by a longitudinal steel tube truss. To evaluate the performance of the flexible rock-shed, experimental and numerical studies are carried out in the present study. Impact tests are conducted on a full-scale partial model of the prototype structure when it is subjected to a falling block of 340 kg. The impact time interval, maximum deflection of the flexible net, tensile forces in the supporting ropes, and axial strains of spring spacer bars are recorded. To further examine the dynamic behavior of the flexible rock-shed, numerical simulations are also carried out by using the explicit finite element code ANSYS/LS-DYNA. It is found that the numerical results coincide well with the experimental data and both the numerical and experimental studies reveal that the structure can withstand impact energy of 50 kJ with all the materials working in the elastic range. The structural details are improved and the basis for the design and construction of similar structures in the future is provided.<br>

scholarly journals Experimental research of two stroke aircraft diesel engine

2019 ◽  
Vol 179 (4) ◽  
pp. 75-79
Author(s):  
Łukasz GRABOWSKI ◽  
Paweł KARPIŃSKI ◽  
Grzegorz BARAŃSKI
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Experimental Studies ◽  
Injection System ◽  
Temperature Control System ◽  
Maximum Pressure ◽  
System Control ◽  
Fuel Injection System ◽  
Measurement Systems ◽  
New Type

This paper presents the results of experimental studies of the opposed-piston diesel engine. This engine was designed during one of the stages of the research on a new-type drive unit for gyrocopter applications. In order to conduct research, a special test stand as well as control and measurement systems were developed. As part of the work on the engine, the fuel injection system, engine temperature control system and measurement systems were designed. In addition, a computer program has been developed for the fuel injection system control (injectors, valves fuel pressure regulators). The paper presents the results of the preliminary tests for a single value of engine speed (1500 rpm) and three values of load defined by torque. The measured value of the indicated pressure made it possible to calculate the maximum pressure. The results obtained from the bench tests were analyzed.

scholarly journals Scientia est potentia

2009 ◽  
pp. 43-60
Author(s):  
Ülo Kaevats
Keyword(s):  
Modern Science ◽  
New Approach ◽  
Natural Laws ◽  
Modern Times ◽  
Natural Objects ◽  
Deductive Method ◽  
New Type ◽  
The Subject ◽  
Understanding Of Science ◽  
Object Of Study

Oma algses mitmetähenduslikkuses on see F. Baconi aforism kõige tihendatum tõdemus, mis tõmbab olemusliku eraldusjoone ühelt poolt antiikse ja keskaegse ning teisalt uusaegse arusaama vahele teadusest ja teadusteadmisest. Artiklis püüab autor anda võimaluste piires tervikpildi uusaja teaduse industriaalselt (tehnoloogiliselt) orienteeritud teadmistüübi tekkimisest. Uusaja teaduse kujunemiseks vajaliku pöörde maailmavaateliste eeldustena tuleb käsitleda: (1) põhimõtteliselt uut subjekti ja objekti käsitust; (2) täiesti uut väärtusruumi, uut teaduse ideoloogiat (ilmalikkus, kriitiline vaim, tõesus ja praktiline kasulikkus); (3) tunnetuslaadi muutust — kontemplatsioonilt interventsioonile, kvaliteedi kirjeldamiselt kvantiteedi uurimisele; (4) looduse käsitlemist Kosmose asemel seaduspäraselt korrastatud objektide “väljana”. Uue tunnetusstiili — empiirilise ja teoreetilise tunnetuse kokkuviimine, hüpoteetilis-deduktiivse metodoloogia kujundamine Galilei poolt, abstraktse ja sünteetilis-tekstilise loomuga spekulatsiooni asendumine uurimisobjekti ehituse, korrapära ja põhjuslikkuse objektiivse analüüsiga, universaalsete loodusseaduste doktriini kujunemine jms—kujunemine konstitueeris uut tüüpi teadmise. Teadmise kui nähtava maailma piltkoopia asemele luuakse teadmine kui loodusobjektide seaduspära analüütiline rekonstruktsioon. See on vormiltmatemaatiline, päritolult eksperimentaalne ning loodusobjektide kontrollimisele ja ümbertegemisele suunatud nn valdamisteadmine.This F. Bacon's aphorism in its original ambiguity is the most condensed belief that draws a distinctive essential line between ancient and medieval understanding of science and scientific knowledge on one hand and modern understanding on the other. The author aims at providing, as far as possible, an integral overview of emerging of the industrially (technologically) orientated type of knowledge of modern times. Ideological/philosophical preconditions of the change necessary for emerging of modern science are: (1) a fundamentally new approach to the subject and object; (2) a completely new system of values, a new ideology of science (secularity, critical spirit, trueness and utilitarianism); (3) a change in manner of cognizance - from contemplation to intervention, from describing quality to studying quantity; (4) treating nature as a naturally organised "field" of objects instead of the Cosmos. Emerging of a new style of cognizance - bringing together of empirical and theoretical cognition, the devise of the hypothetical-deductive method by Galilei, replacement of speculations abstract and synthetic-textual in nature with objective study of the structure, regularity and causality of the object of study, establishment of the doctrine of universal natural laws etc - constituted a new type of knowledge. Knowledge as a copy of the visible world is replaced by knowledge as an analytical reconstruction of the regularity of natural objects. It is so-called dispositive knowledge, morphologically mathematical, originally experimental and aimed at control and alteration of natural objects.

scholarly journals AILU FOR HELMHOLTZ PROBLEMS: A NEW PRECONDITIONER BASED ON THE ANALYTIC PARABOLIC FACTORIZATION

2001 ◽  
Vol 09 (04) ◽  
pp. 1499-1506 ◽  
Author(s):  
MARTIN J. GANDER ◽  
FRÉDÉRIC NATAF
Keyword(s):  
Numerical Experiments ◽  
New Approach ◽  
New Type

We investigate a new type of preconditioner which is based on the analytic factorization of the operator into two parabolic factors. Approximate analytic factorizations lead to new block ILU preconditioners. We analyze the preconditioner at the continuous level where it is possible to optimize its performance. Numerical experiments illustrate the effectiveness of the new approach.

Experimental Study of Air Distribution Characteristics in Room of Stratum Ventilation under Two Kinds of Air Change Times

2013 ◽  
Vol 409-410 ◽  
pp. 668-672
Author(s):  
Yong Mei Xu ◽  
Jian Tang ◽  
Jun Han ◽  
Chu Qin Lin
Keyword(s):  
Experimental Study ◽  
Thermal Comfort ◽  
Experimental Studies ◽  
Air Distribution ◽  
Distribution Characteristics ◽  
Breathing Zone ◽  
Wind Speeds ◽  
Pollutant Concentrations ◽  
New Type ◽  
Better Than

Aimed at a new type of ventilation - stratum ventilation, air distributions at a breathing-zone in a model office were measured under kinds of air changes, the measure parameters in the experimental studies included temperatures, wind speeds and pollutant concentrations, based on which the thermal comfort at a breathing-zone were studied. Experimental results show that, the temperature, pollutant concentration and wind speeds in a breathing-zone under 5 times air changes are better than those under 6 times air changes. The calculating results of PMV and PPD indicate that the thermal comfort at a breathing-zone under 5 times air changes is better. The experimental study is instructive for the development of the ventilation.

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