scholarly journals Freeform Mirror Design for Novel Laser Warning Receivers and Laser Angle of Incidence Sensors

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2569
Author(s):  
Jacek Wojtanowski ◽  
Marcin Jakubaszek ◽  
Marek Zygmunt
Keyword(s):  
Cross Section ◽  
Dynamic Range ◽  
Numerical Aperture ◽  
Merit Function ◽  
Point Of View ◽  
Field Of View ◽  
Stray Light ◽  
Angle Of Incidence ◽  
Detector Position ◽  
Main Challenge

In this paper, we present a novel configuration of an optical angle-of-incidence (AOI) sensor based on the application of a freeform mirror. The main challenge in designing this mirror was to provide a strictly linear transformation between AOI and the spatial position of the spot created on the linear detector array. Another two goals of this paper were to minimize stray light issues (improve the dynamic range) and create an intermediate focus and lateral shift in the detector position with respect to the plane of incidence. From an optical point of view, the designed mirror can thus be understood as the composition of three components: a high-numerical-aperture (NA) fully achromatic f-theta lens in one cross-section and a perfectly focusing lens, combined with a deviating prism in the second (orthogonal) cross-section. In comparison to the standard “shade” methods, the proposed approach allows a constant angular resolution to be maintained over the entire field of view. The mirror was designed on the basis of fundamental geometrical rules by numerically solving differential problems using an innovative scheme based on the minimization of the specific merit function. The proposed method was practically applied to design a freeform mirror for a 90°/120° field-of-view sensor, showing a satisfactory performance.

scholarly journals A Simply Equipped Fourier Ptychography Platform Based on an Industrial Camera and Telecentric Objective

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4913
Author(s):  
Shaohui Zhang ◽  
Guocheng Zhou ◽  
Ying Wang ◽  
Yao Hu ◽  
Qun Hao
Keyword(s):  
Phase Retrieval ◽  
Dynamic Range ◽  
Numerical Aperture ◽  
Complementary Metal Oxide Semiconductor ◽  
Computational Imaging ◽  
Field Of View ◽  
Oxide Semiconductor ◽  
Imaging Method ◽  
Wide Field ◽  
Wide Field Of View

Fourier ptychography microscopy (FPM) is a recently emerged computational imaging method, which combines the advantages of synthetic aperture and phase retrieval to achieve super-resolution microscopic imaging. FPM can bypass the diffraction limit of the numerical aperture (NA) system and achieve complex images with wide field of view and high resolution (HR) on the basis of the existing microscopic platform, which has low resolution and wide field of view. Conventional FPM platforms are constructed based on basic microscopic platform and a scientific complementary metal–oxide–semiconductor (sCMOS) camera, which has ultrahigh dynamic range. However, sCMOS, or even the microscopic platform, is too expensive to afford for some researchers. Furthermore, the fixed microscopic platform limits the space for function expansion and system modification. In this work, we present a simply equipped FPM platform based on an industrial camera and telecentric objective, which is much cheaper than sCMOS camera and microscopic platform and has accurate optical calibration. A corresponding algorithm was embedded into a conventional FP framework to overcome the low dynamic range of industrial cameras. Simulation and experimental results showed the feasibility and good performance of the designed FPM platform and algorithms.

On resolving fine periodic microstructures in the optical microscope

1989 ◽  
Vol 47 ◽  
pp. 364-365
Author(s):  
W.S. Putnam ◽  
C. Viney
Keyword(s):  
Liquid Crystalline ◽  
Numerical Aperture ◽  
Polarized Light ◽  
Normal Incidence ◽  
Optical Microscope ◽  
Angle Of Incidence ◽  
Resolution Limit ◽  
Crystalline Materials ◽  
Periodic Microstructures ◽  
Liquid Crystalline Materials

Many sheared liquid crystalline materials (fibers, films and moldings) exhibit a fine banded microstructure when observed in the polarized light microscope. In some cases, for example Kevlar® fiber, the periodicity is close to the resolution limit of even the highest numerical aperture objectives. The periodic microstructure reflects a non-uniform alignment of the constituent molecules, and consequently is an indication that the mechanical properties will be less than optimal. Thus it is necessary to obtain quality micrographs for characterization, which in turn requires that fine detail should contribute significantly to image formation.It is textbook knowledge that the resolution achievable with a given microscope objective (numerical aperture NA) and a given wavelength of light (λ) increases as the angle of incidence of light at the specimen surface is increased. Stated in terms of the Abbe resolution criterion, resolution improves from λ/NA to λ/2NA with increasing departure from normal incidence.

scholarly journals Combined Method to Remove Endotoxins from Protein Nanocages for Drug Delivery Applications: The Case of Human Ferritin

Pharmaceutics ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 229
Author(s):  
Filippo Silva ◽  
Leopoldo Sitia ◽  
Raffaele Allevi ◽  
Arianna Bonizzi ◽  
Marta Sevieri ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Biological Fluids ◽  
Affinity Purification ◽  
Delivery Systems ◽  
Point Of View ◽  
Uniform Structure ◽  
Structure Stability ◽  
Target Cells ◽  
Clinical Phase ◽  
Main Challenge

Protein nanocages represent an emerging candidate among nanoscaled delivery systems. Indeed, they display unique features that proved to be very interesting from the nanotechnological point of view such as uniform structure, stability in biological fluids, suitability for surface modification to insert targeting moieties and loading with different drugs and dyes. However, one of the main concerns regards the production as recombinant proteins in E. coli, which leads to a product with high endotoxin contamination, resulting in nanocage immunogenicity and pyrogenicity. Indeed, a main challenge in the development of protein-based nanoparticles is finding effective procedures to remove endotoxins without affecting protein stability, since every intravenous injectable formulation that should be assessed in preclinical and clinical phase studies should display endotoxins concentration below the admitted limit of 5 EU/kg. Different strategies could be employed to achieve such a result, either by using affinity chromatography or detergents. However, these strategies are not applicable to protein nanocages as such and require implementations. Here we propose a combined protocol to remove bacterial endotoxins from nanocages of human H-ferritin, which is one of the most studied and most promising protein-based drug delivery systems. This protocol couples the affinity purification with the Endotrap HD resin to a treatment with Triton X-114. Exploiting this protocol, we were able to obtain excellent levels of purity maintaining good protein recovery rates, without affecting nanocage interactions with target cells. Indeed, binding assay and confocal microscopy experiments confirm that purified H-ferritin retains its capability to specifically recognize cancer cells. This procedure allowed to obtain injectable formulations, which is preliminary to move to a clinical trial.

scholarly journals Sources of Variability in the Response of Labeled Microspheres and B Cells during the Analysis by a Flow Cytometer

2021 ◽  
Vol 22 (15) ◽  
pp. 8256
Author(s):  
Adolfas K. Gaigalas ◽  
Yu-Zhong Zhang ◽  
Linhua Tian ◽  
Lili Wang
Keyword(s):  
B Cells ◽  
Laser Beam ◽  
Cross Section ◽  
Mean Fluorescence Intensity ◽  
Numerical Aperture ◽  
Flow Cytometer ◽  
Fluorescence Signal ◽  
Minor Importance ◽  
Reliable Measure ◽  
The Mean

A stochastic model of the flow cytometer measurement process was developed to assess the nature of the observed coefficient of variation (CV%) of the mean fluorescence intensity (MFI) from a population of labeled microspheres (beads). Several sources of variability were considered: the total number of labels on a bead, the path through the laser beam, the optical absorption cross-section, the quantum yield, the numerical aperture of the collection optics, and the photoelectron conversion efficiency of the photomultiplier (PMT) cathode. The variation in the number of labels on a bead had the largest effect on the CV% of the MFI of the bead population. The variation in the path of the bead through the laser beam was minimized using flat-top lasers. The variability in the average optical properties of the labels was of minor importance for beads with sufficiently large number of labels. The application of the bead results to the measured CV% of labeled B cells indicated that the measured CV% was a reliable measure of the variability of antibodies bound per cell. With some modifications, the model can be extended to multicolor flow cytometers and to the study of CV% from cells with low fluorescence signal.

scholarly journals Energy Storage in crystalline Materials based on multivalent Ions

2014 ◽  
Vol 70 (a1) ◽  
pp. C365-C365
Author(s):  
Tina Nestler ◽  
William Förster ◽  
Stefan Braun ◽  
Wolfram Münchgesang ◽  
Falk Meutzner ◽  
...  
Keyword(s):  
Electric Energy ◽  
Lithium Ion ◽  
Point Of View ◽  
Electrical Performance ◽  
Ion Diffusion ◽  
Crystalline Materials ◽  
Multivalent Ions ◽  
Main Challenge ◽  
Energy Conversion And Storage ◽  
Solid State Batteries

Energy conversion and storage has become the main challenge to satisfy the growing demand for renewable energy solutions as well as mobile applications. Nowadays, several technologies exist for the conversion of electric energy into e. g. heat, light and motion or vice versa. Among a large variety of storage concepts, the conversion of electrical in chemical energy is of great relevance in particular for location-independent use. Main factors that still limit the use of electrochemical cells are the volumetric and gravimetric energy density, cyclability as well as safety. The concept for a new thin-film rechargeable battery that possibly improves these properties is presented. In contrast to the widespread lithium-ion technology, the discussed battery is based on the redox reaction of multivalent Al-ions and their migration through solid electrolytes. The ion conduction and insertion processes in the crystalline materials of the suggested cell are discussed under a crystallographic point of view to identify suitable electrode and separator materials. A multilayer-stack of all-solid-state batteries is synthesized by pulsed laser deposition and investigated in situ, i. e. during charge and discharge, by X-ray reflection and diffraction methods. The correlation between crystal structure, morphology and electrical performance is investigated in order to characterize the ion diffusion and insertion process.

scholarly journals Subtraction of Bright Point Sources from Synthesis Images of the Epoch of Reionization

2011 ◽  
Vol 28 (1) ◽  
pp. 46-57 ◽  
Author(s):  
B. Pindor ◽  
J. S. B. Wyithe ◽  
D. A. Mitchell ◽  
S. M. Ord ◽  
R. B. Wayth ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Dynamic Range ◽  
Low Frequency ◽  
Neutral Hydrogen ◽  
Galactic Nuclei ◽  
Point Sources ◽  
Field Of View ◽  
Bright Point ◽  
Line Of Sight ◽  
Diffuse Background

AbstractBright point sources associated with extragalactic active galactic nuclei and radio galaxies are an important foreground for low-frequency radio experiments aimed at detecting the redshifted 21-cm emission from neutral hydrogen during the epoch of reionization. The frequency dependence of the synthesized beam implies that the sidelobes of these sources will move across the field of view as a function of observing frequency, hence frustrating line-of-sight foreground subtraction techniques. We describe a method for subtracting these point sources from dirty maps produced by an instrument such as the MWA. This technique combines matched filters with an iterative centroiding scheme to locate and characterize point sources in the presence of a diffuse background. Simulations show that this technique can improve the dynamic range of epoch-of-reionization maps by 2—3 orders of magnitude.

To the teaching of constitutional anomalies

1927 ◽  
Vol 23 (6-7) ◽  
pp. 672-675
Author(s):  
A. D. Surkov
Keyword(s):  
Human Body ◽  
Point Of View ◽  
Field Of View ◽  
Structural Abnormality ◽  
Body Development ◽  
Healthy State

Anomalies of human body development come into the clinician's field of view usually only when a variant of structural abnormality takes beyond the so-called healthy state the function of the improperly developing organ and sometimes others, topically or functionally related to it. In most cases, the pathogenesis of such diseases is obvious, and individual forms are of interest only from the point of view of symptomatology.

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