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Електромагнітна енергія може змінювати метаболічні і біосинтетичні процеси при певних параметрах імпульсного ЕМП (частота прямування імпульсів, шпаруватість, потужність, експозиція) може уповільнювати і пригнічувати клітинний ріст. Опромінювання в ММ діапазоні РНК і ДНК, що містить вірус приводить до зниження їх інфекційності. Пригнічення роста культур бактерій, зміна фагоцитарної активності, біосинтезу білків, ультраструктурні зміни в клітинах при взаємодії ЕМП КВЧ діапазону. В дослідженнях з мікроорганізмами було встановлено, що біологічний ефект від дії ЕМП на мікроорганізми носив резонансний характер. В якості одного з основних механізмів гнітючої дії КВЧ випромінювання на шкідливі мікроорганізми є роль біологічних мембран в реакціях мікроорганізмів на ЕМВ. Електричні явища, які проходять в біомембранах, відіграють виключно важливу роль. Утворення трансмембранної різниці потенціалів обумовлено виборчої іонною провідністю мембран в цілому, є відмінним діелектриком, так біошари електроізолюючих ліпідних молекул здатні витримувати напруженість ЕП порядку 105 В/см. Величина електричного потенціалу на мембрані вкрай важлива. За сучасною теорією трансмембранного транспорту, а саме ЕП всередині мембрани складає потоки необхідних речовин із навколишнього середовища всередину клітини та з клітини в навколишнє середовище через спеціальні гідрофільні канали, скоріше всього, ліпопротеїнової природи. Швидкість проникнення іонів через мембрану визначається такими властивостями, як товщина, значення ДП, наявність фіксованих електричних зарядів на мембрані, розміри і число пор в мембрані, наявність фіксованих зарядів в порах та деякими іншими.

Introduction: Functional near-infrared spectroscopy (fNIRS) is an imaging method in which a light source and detector are installed on the head; consequently, the re-emission of light from human skin contains information about cerebral hemodynamic alteration. The spatial probability distribution profile of photons penetrating tissue at a source spot, scattering into the tissue, and being released at an appropriate detector position, represents the spatial sensitivity. Methods: Modeling light propagation in a human head is essential for quantitative near-infrared spectroscopy and optical imaging. The specific form of the distribution of light is obtained using the theory of perturbation. An analytical solution of the perturbative diffusion equation (DE) and finite element method (FEM) in a Slab media (similar to the human head) makes it possible to study light propagation due to absorption and scattering of brain tissue. Results: The simulation result indicates that sensitivity is slowly decreasing in the deep area, and the sensitivity below the source and detector is the highest. The depth sensitivity and computation time of both analytical and FEM methods are compared. The simulation time of the analytical approach is four times larger than the FEM. Conclusion: In this paper, an analytical solution and the performance of FEM methods when applied to the diffusion equation for heterogeneous media with a single spherical defect are compared. The depth sensitivity along with the computation time of simulation has been investigated for both methods. For simple and Slab modes of the human brain, the analytical solution is the right candidate. Whenever the brain model is sophisticated, it is possible to use FEM methods, but it costs a higher computation time.

Divertor Operational Instrumentation (DOI) measures mechanical, electromagnetics and thermal parameters of the ITER Divertor Cassettes. The maintenance of the Cassettes requires their periodic removal and replacement by remote handling tools. The remote handling connector (RHC) of the DOI includes electrical and optical connections for the instrumentation cables, which must be disconnected during maintenance. The available space for the DOI RHC design is limited and the environmental conditions inside the Vacuum Vessel include high vacuum 10^-5 Pa, high temperature up to 350 °C and neutron and gamma-ray irradiation up to 1 GGy by the end of ITER operation. The access of remote handling tools is limited in the operating space surrounding DOI RHC. A study of existing connectors designed for plasma diagnostics electrical cables indicated that the concepts could not be adapted as such for the DOI RHC. The main concerns were related to the increased limitation of space, and the need to incorporate optical contacts for the fiber-optic cables that should be aligned with high precision to minimize optical losses. A dedicated design was required and developed. A novel extending DOI RHC concept was selected as it minimizes the required design changes to the surrounding systems. The concept consists of a cassette socket with an extending link located on the Divertor Cassette and a permanently installed vacuum vessel socket. The concept relies on the actuation of linear motion by the bolting tools of Cassette Toroidal Mover (CTM) manipulator and the flexibility of the cabling during the actuation. A physical full-size mock-up of the DOI RHC was manufactured to test the design solutions. The functionality of the mechanical structure in regards to remote handling operations were tested at remote handling connector platform (RHCP) at VTT Tampere Finland. Suppliers of optical connectors and ferrules were contacted to discuss the requirements of DOI RHC and commercial off-the-shelf optical components. Since there is no commercially available solution for attaching the fiber to the ferrule which would meet the aforementioned requirements, initial soldering tests were performed. The developed DOI RHC design provides input to the following design phases.

Density-Based clustering are the main clustering algorithms because they can cluster data with different shapes and densities, but some of these algorithms have high time complexity like OPTICS (Ordering Points to Identify Clustering Structure) and DBSCAN (Density-based spatial clustering of applications with noise) where the time complexity up to O( n 2 ). In this paper, we use an approach to reduce this complexity by providing fuzzy clusters to OPTICS, which make the process of finding neighbours within an only narrow region (fuzzy group) instead of searching all the state space making the algorithm faster than the original one with keeping almost the same accuracy of the innovative algorithm. The results show that there is an improvement in execution time using some synthetic and real datasets with high dimensions.

There are some factors that play a crucial role in deciding the image quality during the optical as well as the micrographic association with the technique of the shadow casting in which contrast of the image has influenced with obliquely depositing of a thin layer of the metal during the process of the microscopic preparations. Further castingadvantages of the using shadow technique are to be observed during the process if shadow casting itself. Shadow casting posses’ number of the advantages over the other casting methods. The most prominent advantage is that if the height and thickness of an object is not completely flat that can be easily notice by the shadow of that object. The lengths of the shadow of the uneven part are so differentiate from other part that can be easily determined. Shadow casting uses the scattering power or even the optical efficiency to bring out the specimens contours and will easily get notice in order to check the flatness of the surfaces.

A cost-effective stereolithography for medium-scale components is developed to fabricate 3D components with high build speed and resolution from photo-curable resin. The developed SLA utilizes a focused light beam of wavelength range (300 nm–700 nm) coming from the DLP projector and passes through the objective lens and finally imposed on the platform containing a layer of photo-curable resin. After focusing the light beam on the liquid resin layer, the photo-polymerization reaction occurs and the liquid resin becomes solid. Thus, the 3D object is fabricated layer by layer curing of liquid resin. The photopolymer used in this experimentation is polyethylene glycol di-acrylate and Irgacure 784 as photo-initiator. The Creo 3.0 software is used for modelling of 3D objects. A special MATLAB code is developed for slicing of the 3D model and displaying the sliced image one by one through DLP projector. The Arduino microcontroller with stepper motor and ball screw is used to control the motion of Z-stage platform. The Creation workshop software is also used to control motion of the Z-stage and period to display the sliced images through DLP projector. The medium-scale 3D objects with rectangular, square, and circular cross-sections are obtained by curing the aforementioned photo-curable resin. It is observed that the 3D objects are best cured for two seconds curing time with 0.1 mm curing depth along Z-axis.

In this research, a free rotation and distortion projector doublet electromagnetic lens was designed by computer-aided using electron optical design (EOD) program. This lens consists of two identical lenses. This lens's focal and projector characteristics were calculated in the two max magnification regions by changing the axial magnetic flux density in one of the two single lenses by changing its axial bore diameter. The results showed the possibility of obtaining a free rotation and distortion projector doublet electromagnetic lens in the first max magnification regions, and it has the min magnitude for the projector focal length.

Computational analysis has been presented in this paper to discuss one of the approaches of optimum synthesis for the design of magnetics lenses (analytical method). This investigation concentrates on finding the optimum design for single-pole piece magnetics lenses magnetically unsaturated to use in construction magnetics optical systems for transmission electron microscopes (TEM). In this investigation, the same computer program (EOD) program is the geometry of the magnetic lens and the axial magnetic field generated and drawing lines of magnetic flux through the lens. The electron beam's trajectory and objective optical characteristics have been calculated, taking the values of axial magnetics field as input data to calculate the objective length of focal and coefficient of aberrations (spherical and chromatic). In present work has been studied the impact of geometrical parameters for magnetics lenses (axial bore diameter). This investigation's importance is the possibility of determining suitable geometry of the magnetics lenses for benefiting from it in making transmission electron microscopes.

Visible Light Positioning (VLP) is a promising indoor localization technology for providing highly accurate positioning. In this work, a VLP implementation is employed to estimate the position of a vehicle in a room using the Received Signal Strength (RSS) and fixed LED-based light transmitters. Classical VLP approaches use lateration or angulation based on a wireless propagation model to obtain location estimations. However, previous work has shown that machine learning models such as Gaussian processes (GP) achieve better performance and are more robust in general, particularly in presence of non-ideal environmental conditions. As a downside, Machine Learning (ML) models require a large collection of RSS samples, which can be time-consuming to acquire. In this work, a sampling scheme based on active learning (AL) is proposed to automate the vehicle motion and to accelerate the data collection. The scheme is tested on experimental data from a RSS-based VLP setup and compared with different settings to a simple random sampling.

The Advanced Virgo Plus project aims to increase the sensitivity of the Virgo gravitational-wave detector, given the forthcoming O4 Observing Run. One of the major upgrades is the addition of the Signal Recycling Mirror in the optical layout. This additional mirror will provide a broadband improvement to the sensitivity curve of the instrument, but poses significant challenges in the acquisition and operation of the detector’s working point. The process which brings the main optical components from the uncontrolled state to the final working point, which ensures the best detector sensitivity, is called lock acquisition: the lock acquisition is made by moving through increasingly more complex configurations toward the full control of all the interferometer’s longitudinal degrees of freedom. This paper will focus on the control of the Dual-Recycled Michelson Interferometer (DRMI, the central part of the Virgo interferometer), presenting a comprehensive study of the optical simulations used in the design and the commissioning of this configuration. Treated topics include: the characterization of optical fields, powers, and error signals for the controls; the development of a trigger logic to be used for the lock acquisition; the study of the alignment sensing and control system. The interdependence between the three items has also been studied. Moreover, the validity of the studied techniques will be assessed by a comparison with experimental data.

A detailed knowledge of the melting and solidification of a suspension of Nano-Encapsulated Phase Change Materials (NEPCM) is essential to analyze the thermal behavior of the PCM materials. This study investigates the convective heat analysis of NEPCM suspensions during the solidification and melting process in a porous domain. The inner cylinder of the eccentric annulus is used as a thermally active wall for charging and discharging the suspension while an adiabatic condition is used at the outer wall of the cylinder. The thermal behavior of the suspension comprising nano-encapsulated PCM is analyzed throughout the melting and solidification process. The PCM core fusion temperature and eccentricity of the annulus affect the thermal performance. The overall heat transmission decreases when the PCM core fusion heat approaches to the suspension temperature. An increase in thermal convection between the nanofluid and porous matrix reduces the Nusselt number in the liquid but increases the heat transmission in the porous foam. An increase in Stefan number enhances the heat transfer in the enclosure.

Transverse galloping is a type of flow-induced vibration (FIV) that leads to critical design considerations for engineering structures. A purely nonlinear energy sink (NES) composed of a ball free to rotate in a circular track experimentally mitigated the galloping of a square in a previous study. The current study introduces a model for simulating the dynamics of the square prism coupled with a ball-in-track (BIT) NES and predicting the system behaviour at high flow speeds beyond the limits of the previously presented experiments. Numerical simulations employ the fitting of experimental data as inputs to define parameters. Wind tunnel static experiments provide the galloping force coefficient [[EQUATION]] relative to the prism angle of attack. Additionally, free rotation tests allow evaluating the ball damping coefficient [[EQUATION]] as a function of its mass and the NES track radius. The result of the rotation tests provides a critical angular speed beyond which the ball damping increases non-linearly. We point out the damping variation as an advantage of the BIT-NES; less damping at low angular velocities helps the ball start its rotation, while relatively large damping at higher speeds dissipates more energy from the vibrating system. Numerical results exhibit four response modes for the NES; oscillatory at low flow speeds, intermittent within a small range of higher flow speeds, rotational at higher flow speeds, and ineffective regime at flow speeds out of the NES effective range. Modelling the primary mass as a parametric excitation source for the NES provides an analytical estimation of the boundary between the oscillatory and intermittent regimes. Furthermore, we advance an analytical analysis of the power flow across the integrated prism-NES system to explain the NES behaviour and predict the limit of its effective range.

The cell-type continuous electromagnetic radiation system is a demonstration device capable of generating high-power millimeter electromagnetic waves of a specific wavelength and observing their effects on living organisms. It irradiates a biological sample placed in a 30 × 30 × 50 cm3 cell with electromagnetic waves in the 3.15-mm-wavelength region (with an output of ≥1 W) and analyzes the temperature change of the sample. A vacuum electronic device-based coupled-cavity backward-wave oscillator converts the electron energy of the electron beam into radiofrequency (RF) energy and radiates it to the target through an antenna, increasing the temperature through the absorption of RF energy in the skin. The system causes pain and ultimately reduces combat power. A cell-type continuous electromagnetic radiation system consisting of four parts—an electromagnetic-wave generator, a high-voltage power supply, a test cell, and a system controller—generates an RF signal of ≥1 W in a continuous waveform at a 95-GHz center frequency, as well as a chemical solution with a dielectric constant similar to that of the skin of a living organism. An increase of 5 °C lasting approximately 10 s was confirmed through an experiment.

In this work, a parametric up-converter amplifier is introduced as a wideband impedance-matching network. Chu’s limit restricts the minimum Q-factor of unloaded small antennas. However, the practical bandwidth (BW) of small antennas is defined by their loaded Q-factor. By connecting a small antenna to an amplifier with a real input impedance that is several times greater than the radiation resistance of the antenna, we propose increasing the return loss, which leads to a reduction in the loaded Q-factor and an increase in the BW. In addition, a parametric amplifier is used because, in comparison with transistor amplifiers, it offers low-noise characteristics. The gain of the low-noise parametric amplifier compensates for the loss due to the imposed mismatch. Our simulation result shows BW improvements up to 32 times can be accomplished by trading 2 dB of noise figure (NF), compared to the 15 dB suggested by Chu’s limit for a lossy antenna. Accepted version

Colloidal nanocrystals have great potential for next-generation solid-state lighting due to their outstanding emission and absorption tunability via size and morphology, narrow emission linewidth, and high photoluminescence quantum yield (PLQY). However, the losses due to self-and interabsorption among multitudes of nanocrystals significantly decrease external quantum yield levels of light-emitting diodes (LEDs). Here, we demonstrate efficient white LEDs via CdSe/CdS dot to ""dot-in-rod"" transition that enabled a large Stokes shift of 780 meV and significantly reduced absorption losses when used in conjunction with near-unity PLQY ZnCdSe/ZnSe quantum dots (QDs) emitting at the green spectral range. The optimized incorporation of nanocrystals in a liquid state led to the white LEDs with an ultimate external quantum efficiency (EQE) of 42.9%, with a net increase of EQE of 10.3% in comparison with white LEDs using CdSe/CdS dots. Therefore, combinations of nanocrystals with different nanomorphologies hold high promise for efficient white LEDs., Scientific and Technological Research Council of Turkey (TÜBİTAK); Turkish Academy of Sciences (TU?BA-GEBIP; The Young Scientist Award Program)

In harsh environments, Fe-based amorphous coatings can provide effective protection for equipment. A method of thickness measurement of thin layer and quality evaluation based on high-frequency water-immersion ultrasonic testing and imaging is proposed here. In this paper, because of the interface echoes of the micron-scale coating in the aliasing of ultrasonic testing signals, wavepacket decomposition and extraction technology proposed according to the matching pursuit theory is used to separate the interface echoes. After using the narrow pulse replacement method, the coating structure imaged is reconstructed. The decomposed interface echoes will not be mixed again, thus reflecting the coating thickness information more accurately. Consequently it can be used to evaluate the coating quality. Finally, the experimental results show that the coating structure image can be reconstructed after the high-frequency water-immersion ultrasonic scanning signals are processed with the above method. The relative error of the coating thickness detection is only 3.13% compared with the scanning electron microscope (SEM) results. At the same time, the coating spraying quality can be evaluated effectively through the imaged results.

The atomic force microscope (AFM) is widely used in many fields such as biology, materials, and physics due to its advantages of simple sample preparation, high-resolution topography measurement and wide range of applications. However, the low scanning speed of traditional AFM limits its dynamics process monitoring and other further application. Therefore, the improvement of AFM scanning speed has become more and more important. In this review, the working principle of AFM is first proposed. Then, we introduce the improvements of cantilever, drive mechanism, and control method of the high-speed atomic force microscope (HS-AFM). Finally, we provide the next developments of HS-AFM.

A 23-year-old man with refractive error as in [figure 1A][1] was planned for LASIK (Laser assisted in-situ keratomileusis) refractive surgery (ZEISS MEL 90). After flap preparation, the subject was accidentally fired on by excimer laser at fluence test settings[1][2] instead of that for the

CTA (Cherenkov Telescope Array) is the next generation ground-based observatory for gamma-ray astronomy at very-high energies. The Large-Sized Telescope prototype (LST-1) is located at the Northern site of CTA, on the Canary Island of La Palma. LSTs are designed to provide optimal performance in the lowest part of the energy range covered by CTA, down to $\simeq 20$ GeV. LST-1 started performing astronomical observations in November 2019, during its commissioning phase, and it has been taking data since then. We present the first LST-1 observations of the Crab Nebula, the standard candle of very-high energy gamma-ray astronomy, and use them, together with simulations, to assess the basic performance parameters of the telescope. The data sample consists of around 36 hours of observations at low zenith angles collected between November 2020 and March 2022. LST-1 has reached the expected performance during its commissioning period - only a minor adjustment of the preexisting simulations was needed to match the telescope behavior. The energy threshold at trigger level is estimated to be around 20 GeV, rising to $\simeq 30$ GeV after data analysis. Performance parameters depend strongly on energy, and on the strength of the gamma-ray selection cuts in the analysis: angular resolution ranges from 0.12 to 0.40 degrees, and energy resolution from 15 to 50%. Flux sensitivity is around 1.1% of the Crab Nebula flux above 250 GeV for a 50-h observation (12% for 30 minutes). The spectral energy distribution (in the 0.03 - 30 TeV range) and the light curve obtained for the Crab Nebula agree with previous measurements, considering statistical and systematic uncertainties. A clear periodic signal is also detected from the pulsar at the center of the Nebula., Accepted in ApJ. v3: updated author list and acknowledgements, fixed typos and other minor issues

The first direct detection of gravitational waves opened the possibility of mapping the Universe via this new and independent messenger. Indeed, during their propagation, gravitational waves pick up information about the spacetime as they are affected by its expansion and by the matter structures along the propagation path. The aim of this Thesis is to investigate which cosmological information is accessible from a gravitational wave detection, with a specific interest in the late time Universe.

Ultrafast laser fabrication of NV− centres has been shown to produce highly coher- ent NV− centres within diamond with high fabrication accuracy, expanding the applicability of the defect within quantum technologies. However this technique is yield limited due to a required thermal annealing step. Within, this thesis presents the first, near-unity yield, fabrication of single NV− centres in commerically available high purity diamond using a homebuilt ultrafast fabrication system. Thermal annealing is replaced by a low energy ultrafast pulse train which allows for NV− generation to be monitored using confocal fluorescence microscopy. Each fabrication site showed a g(2)(0) < 0.5, demonstrating singularity. The fabrication precision has been calculated to be isotropically ∼250 nm, suggesting that nitrogen concentration is the limiting factor. This thesis details the construction and operating principles of the homebuilt fabrication system, which includes the use of adaptive optic elements. Additionally this thesis investigates phenomena observed during ultrafast farbication of NV− centres using ab initio calculations of defect interactions within diamond. These simulations suggest that hybridisation may be responsible for transient effects seen during fabrication. In addition, these simulations demonstrate that the ultrafast laser fabrication of defects may provide an invaluable window into defect formation and fabrication in the solid state.

Laser-Induced Grating Spectroscopy (LIGS) is a non-intrusive optical diagnostic primarily used for temperature measurements in the gas phase. The technique boasts excellent accuracy and precision, achieved at relatively low cost and complexity, compared to similar diagnostics. A drawback of the technique is its temporal resolution, which has generally been limited to 10 Hz without compromising the accessibility of the technique (through the use of toxic tracer species or expensive lasers). The discovery of a new LIGS tracer species, biacetyl, which enables the use of accessible high repetition rate lasers is presented. Temperature measurements, obtained at a rate of 1 kHz, and the application of the technique to study thermoacoustic instabilities, have been demonstrated. A significant problem for LIGS is an inherently poor spatial resolution due to an elongated (in the axial direction) measurement region. A novel approach enabling simultaneous 1-D spatially-resolved LIGS measurements in the axial direction is presented. This capability can be incorporated into standard LIGS experiments with a negligible increase in cost or complexity, thus preserving the accessibility of the technique. A computational model for the approach was developed and validated. A preliminary experiment demonstrated a 93% improvement in axial spatial resolution, as well as a three-fold increase in the number of single-shot measurements obtained, when compared to a standard LIGS configuration. To exploit the significant advantages of the technique by enhancing its accessibility, a unique transportable LIGS system (named PILOT) was designed, manufactured and characterised. The mobile, self-contained system is capable of collecting tracer-free LIGS measurements at a rate of 400 Hz. An accuracy of less than 0.37% and precision of +/-0.7% was demonstrated for temperature measurements in room air. Characterisation experiments showed that the use of an avalanche photodetector for signal detection would permit the use of the system in scattering environments. A novel systematic investigation of tracer-free LIGS in different gases highlighted the polarisability of a gas as a key indicator for performance of the technique. These findings will inform experimental design for future applications. Finally, the deployment of PILOT in a research facility was demonstrated.

Organic light-emitting diodes (OLEDs) are emerging as one of the most promising candidates for next-generation optoelectronics. However, most commercial OLED displays are fabricated using organometallic phosphors containing rare transition metals, such as Ir(III) and Pt(II). Recently, the development of efficient phosphorescent emitters based on abundant Au(III) is drawing considerable attention. Here, rational molecular design of a series of Au(III) organometallic complexes consisting of asymmetric C^C^N ligands and carbazole moieties functionalized by phenyl or mesityl groups is presented. The synthesized complexes exhibit shortened radiative lifetimes, and reach improved photoluminescence quantum yield, ηPL, of greater than 93% in thin films. Moreover, the asymmetric molecular design induces anisotropic emission with a high ratio of horizontally oriented transition dipole moment of up to 82% in host-guest films. Accordingly, high-performance OLED devices with record-high external quantum efficiencies, ηext, and current efficiencies, ηCE, of up to 27% and 89 cd A−1, respectively, are demonstrated. It is believed that the molecular design of anisotropic Au(III) emitters will be greatly facilitated by the fundamental principles and theoretical analysis presented here., Advanced Optical Materials, 11 (12), ISSN:2195-1071

Amblyopia is a significant issue for children worldwide, and current treatment methods have drawbacks that can hinder treatment effectiveness and/or patient experience. This study proposes a new treatment method using holographic diffusers while also comparing their optical characteristics to a current treatment method (Bangerter foils). Holographic diffusers were developed by optically patterning thin polymer layers on a micron scale. Two compositions of photopolymer (acrylamide and diacetone acrylamide based) are analysed herein. Characterisation shows that holographic diffusers of either composition can achieve a wide range of on-axis intensity reductions, allowing for precise and customisable treatment levels by altering recording exposure time in a low-cost and durable manner.

This chapter gives a complete but concise introduction to electron cryomicroscopy. The theoretical and practical background is discussed together with a review of applications to the three-dimensional structural analysis of biological macromolecules or macromolecular assemblies. It includes basic descriptions of how to analyse the structures of molecules arranged in the form of two-dimensional crystals, helical arrays or as single particles with or without symmetry. The chapter concludes by anticipating trends towards increased automation, development of better electronic cameras and increasing use of electron tomography for analysis of cell structure. Keywords: cryoTEM; electron cryomicroscopy; electron microscopy; electron scattering; helical particles; icosahedral particles; image processing in cryoTEM; phasing; radiation damage; three-dimensional image reconstruction; two-dimensional crystals

SignificancePerturbation and differential Monte Carlo (pMC/dMC) methods, used in conjunction with nonlinear optimization methods, have been successfully applied to solve inverse problems in diffuse optics. Application of pMC to systems over a large range of optical properties requires optimal "placement" of baseline conventional Monte Carlo (cMC) simulations to minimize the pMC variance. The inability to predict the growth in pMC solution uncertainty with perturbation size limits the application of pMC, especially for multispectral datasets where the variation of optical properties can be substantial.AimWe aim to predict the variation of pMC variance with perturbation size without explicit computation of perturbed photon weights. Our proposed method can be used to determine the range of optical properties over which pMC predictions provide sufficient accuracy. This method can be used to specify the optical properties for the reference cMC simulations that pMC utilizes to provide accurate predictions over a desired optical property range.ApproachWe utilize a conventional error propagation methodology to calculate changes in pMC relative error for Monte Carlo simulations. We demonstrate this methodology for spatially resolved diffuse reflectance measurements with ±20% scattering perturbations. We examine the performance of our method for reference simulations spanning a broad range of optical properties relevant for diffuse optical imaging of biological tissues. Our predictions are computed using the variance, covariance, and skewness of the photon weight, path length, and collision distributions generated by the reference simulation.ResultsWe find that our methodology performs best when used in conjunction with reference cMC simulations that utilize Russian Roulette (RR) method. Specifically, we demonstrate that for a proximal detector placed immediately adjacent to the source, we can estimate the pMC relative error within 5% of the true value for scattering perturbations in the range of [-15%,+20%]. For a distal detector placed at ∼3 transport mean free paths relative to the source, our method provides relative error estimates within 20% for scattering perturbations in the range of [-8%,+15%]. Moreover, reference simulations performed at lower (μs'/μa) values showed better performance for both proximal and distal detectors.ConclusionsThese findings indicate that reference simulations utilizing continuous absorption weighting (CAW) with the Russian Roulette method and executed using optical properties with a low (μs'/μa) ratio spanning the desired range of μs values, are highly advantageous for the deployment of pMC to obtain radiative transport estimates over a wide range of optical properties.

Este artículo presenta la experiencia del diseño y construcción de un telescopio con componentes impresas en 3d a través de un trabajo de fin de grado de ingeniería.

Two dimensional (2D) Photonic crystals (PhCs) based cross waveguide structure (CWs) consisting of resonant cavity is investigated in this paper. Investigations are done using Two Dimensional Finite Difference Time Domain (2DFDTD) method. Transmission characteristics have been obtained for different radii of central rod placed at crossing point of two waveguides and number of regular rods surrounding central rod. Nonlinear behavior is also studied for different operating wavelengths.

With their unique optoelectronic properties, perovskite nanocrystals are highly advantageous semiconductor materials for tailored light applications including an interaction with circularly polarized light. Although chiral perovskite nanocrystals have been obtained by the adsorption of chiral molecules, their chiroptical response is still intrinsically weak. Alternatively, perovskites have been combined with artificial chiral surfaces demonstrating enhanced chiroptical responses. However, bulk perovskite films of considerable thickness were required, mitigating the perovskite’s photoluminescence efficiency and processability. Here we developed a hybrid system of a dielectric chiral nanoantenna array that was coated with a monolayer of cubic all-inorganic lead halide perovskite nanocrystals. By tuning the thickness of the perovskite film down to one monolayer of nanocrystals, we restricted the interactions exclusively to the near-field regime. The chiral surface built of z-shaped Si nanoantennas features pronounced chiral resonances in the visible to IR region. We demonstrate that the two-photon excited photoluminescence emission of the nanocrystals can be enhanced by up to one order of magnitude in this configuration. This emission increase is controllable by the choice of the excitation wavelength and polarization with an asymmetry in emission of up to 25% upon left and right circularly polarized illumination. Altogether, our findings demonstrate a pathway to an all-optical control and modulation of perovskite light emission via strong polarization sensitive light–matter interactions in the near-field, rendering this hybrid system interesting for sensing and display technologies.

Recent efforts in single-cell research call for precise liquid level detection (LLD) for end-effectors to manipulate small volume of liquid sample like nano- to pico-liter droplets. Existing LLD methods, however, are yet satisfactory for such delicate micromanipulation tasks. This paper presents a vision-based contact type LLD method, which adopts the hardware settings normally used in typical micromanipulation scenarios. The detection principle is based on generation of patterned ripples when the end-effector (e.g., glass micropipette), that is being vibrated, moving to get contact with the liquid surface. Through the microscopic imaging system in micromanipulation, the image frames of patterned ripples like concentric circles are recorded, from which the wavelength is extracted to determine the contact moment. The vision-based LLD method was cross-validated by electrical impedance-based method. Experiments revealed that the best detection accuracy was 0.04 m, only limited by the micromanipulators positioning resolution. And, the method was robust to various micromanipulation settings, such as illumination intensity, microscopy magnification, exposure time and focal plane. Moreover, this method was successful in detecting the surface of droplets with volume as low as 450 pL of different liquid. Given its generality, this method is expected to be powerful in many micromanipulation scenarios involving liquid handling tasks, including industry.

ispartof: IEEE PHOTONICS JOURNAL vol:14 issue:4 status: published

Tunable lens technology inspired by the human eye has opened a new paradigm of smart optical devices for a variety of applications due to unique characteristics such as lightweight, low cost, and facile fabrication over conventional lens assemblies. The fast-growing demands for tunable optical lenses in consumer electronics, medical diagnostics, and optical communications require the lens to have a large focal length modulation range and high compactness. Herein, for the first time, an all-solid tunable soft lens driven by highly transparent dielectric elastomer actuators (DEAs) based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) and waterborne polyurethane (PEDOT:PSS/WPU) transparent electrodes is developed. The deformation of the tunable soft lens is achieved by the actuation of DEAs, mimicking the change of the surface profile of the human eye to achieve remarkable focal length variations. Upon electrical activation, this tunable soft lens can vary its original focal length by 209%, which is one of the highest among current tunable soft lenses and far beyond that of the human eye. This study demonstrates that transparent DEAs are capable of achieving focus-variation functions, and potentially useful in artificial robotic vision, visual prostheses, and adjustable glasses, which will induce significant effects on the future development of tunable optics.

A line laser with high power as the background light source for the design of a new photoelectric detection target is proposed in this paper, aiming to improve the detection ability of the traditional photoelectric detection target under low background illumination. The laser emitted pulse waveform function and the laser echo pulse response function were used to establish the mathematical model of the reflected echo power of projectile in the detection area and derive the calculation function of minimum detectable echo power in the line laser detection screen, according to information of the line laser emitted power, incident angle of projectile, duration time and detection distance of projectile passing through the line laser detection screen. Calculations and experimental results showed that the design method of line laser detection screen and calculation model of laser echo power are reasonable, and the detection ability of line laser detection screen is obviously higher than that of traditional photoelectric detection screen, especially in low background illumination; at the same time, the designed line laser detection screen was used to combine a six line laser detection screen intersection test system, based on live ammunition for shooting. The test system is stable and able to obtain the dynamic parameters of the flying projectile, verifying that the design of the line laser detection screen in new photoelectric detection target can be suitable for shooting range test applications.

The influence of neutron and gamma radiation on single mode fiber cables is experimentally conducted. Attenuation due to incident radiation is measured. Attenuation is determined by laser source and power meter in Africa Teleco Company, besides attenuation recovery is attained. The Gamma experiment is carried out within Egypt Mega Gamma1 in National Center for Radiation Research and Technology of Egyptian Atomic Energy Authority (EAEA). In this experiment, the cable is degraded by gamma radiation of doses 5KGy, 10KGy, 15KGy and 25KGy and dose rate of 1KGy/26.4 min. However the attenuation based on neutron degradation is executed in the second Egyptian Training Research Reactor (ETRR-2), in front of neutron beam facility (NBF) in ETRR-2 which has a flux of 1.5x107(n/cm2.sec). For both experiments, the experimental measurements are done at two different spectral wavelengths of 1310 nm and 1550 nm. A comparison between obtained results is investigated.

In this paper, a new optimized quadrant pyramid antenna array (O-QPAA) structure is proposed for back lobe minimization of planar antenna arrays (PAA). Based on the PAA size, it is thought to be formed of a number of concentric co-planar squared antenna arrays (SAA) or rectangular antenna arrays (RAA) placed in the X-Y plane. Initially, to construct a non-optimized QPAA, these concentric SAAs or RAAs are distributed vertically along the Z-axis with uniform vertical spacing. Thereby, the QPAA is treated as a hybrid of uniform SAAs or RAAs and a linear antenna array (LAA). However, the QPAA may have a main beam and back lobe of the same amplitude. To address this issue, the O-QPAA structure is proposed, which allows for the minimization of the back lobe while still controlling the QPAA pattern features such as side lobe level (SLL) and half power beamwidth (HPBW). The particle swarm optimization (PSO) approach is employed in this O-QPAA structure to identify the optimal values of the three main QPAA parameters, which are inter-element spacing within each SAA or RAA, vertical spacing, and the non-uniform excitations of the LAA to form the entire O-QPAA radiation pattern.

Reliable spatially resolved compositional analysis through atom probe tomography requires an accurate placement of the detected ions within the three-dimensional reconstruction. Unfortunately, for heterogeneous systems, traditional reconstruction protocols are prone to position some ions incorrectly. This stems from the use of simplified projection laws which treat the emitter apex as a spherical cap, although the actual shape may be far more complex. For instance, sampled materials with compositional heterogeneities are known to develop local variations in curvature across the emitter due to their material phase specific evaporation fields. This work provides three pivotal precursors to improve the spatial accuracy of the reconstructed volume in such cases. First, we show scanning probe microscopy enables the determination of the local curvature of heterogeneous emitters, thus providing the essential information for a more advanced reconstruction considering the actual shape. Second, we demonstrate the cyclability between scanning probe characterization and atom probe analysis. This is a key ingredient of more advanced reconstruction protocols whereby the characterization of the emitter topography is executed at multiple stages of the atom probe analysis. Third, we show advances in the development of an electrostatically driven reconstruction protocol which are expected to enable reconstruction based on experimental tip shapes.