Principle Of Diffraction Research Articles

Spatially resolved scatter measurement of diffractive micromirror arrays.

Spatial light modulators (SLMs) support flexible system concepts in modern optics and especially phase-only SLMs such as micromirror arrays (MMAs) appear attractive for many applications. In order to achieve a precise phase modulation, which is crucial for optical performance, careful characterization and calibration of SLM devices is required. We examine an intensity-based measurement concept, which promises distinct advantages by means of a spatially resolved scatter measurement that is combined with the MMA's diffractive principle. Measurements yield quantitative results, which are consistent with measurements of micromirror roughness components, by white-light interferometry. They reveal relative scatter as low as 10^-4, which corresponds to contrast ratios up to 10,000. The potential of the technique to resolve phase changes in the subnanometer range is experimentally demonstrated.

Development of hard X-ray photoelectron SPLEED-based spectrometer applicable for probing of buried magnetic layer valence states

A novel design of high-voltage compatible polarimeter for spin-resolved hard X-ray photoelectron spectroscopy (Spin-HAXPES) went into operation at beamline BL09XU of SPring-8 in Hyogo, Japan. The detector is based on the well-established principle of electron diffraction from a W(001) single-crystal at a scattering energy of 103.5eV. It's special feature is that it can be operated at a high negative bias potential up to 10kV, necessary to access the HAXPES range. The polarimeter is operated behind a large hemispherical analyzer (Scienta R-4000). It was optimized for high transmission of the transfer optics. A delay-line detector (20mm dia.) is positioned at the exit plane of the analyzer enabling conventional multichannel intensity spectroscopy simultaneously with single-channel spin analysis. The performance of the combined setup is demonstrated by the spin-resolved data for the valence-region of a FeCo functional layer of a tunneling device, buried beneath 3nm of oxidic material. The well-structured spin polarization spectrum validates Spin-HAXPES in the valence energy range as powerful method for bulk electronic structure analysis. The spin polarization spectrum exhibits a rich structure, originating from clearly discernible transitions in the majority and minority partial spin spectra.

Comparison of Empirical Path Loss Propagation Models with Building Penetration Path Loss Model

Path loss Propagation models plays a fundamental role in planning and designing of mobile radio communication link. In this paper a building penetration path loss model was developed using AUTOCAD. The model involved the combination of three mechanisms of signal propagation; refraction, reflection and diffraction. The signal penetration through building wall was modelled as refraction using Fresnel Refraction Coefficient and the signal propagation through the roof was modelled as diffraction using the principle of knife-edge diffraction. The developed building penetration path loss model was compared with some empirical path loss models namely, Log distance path loss, Okumura, HATA and COST-231 models and the results showed that the models compared accurately with the existing path loss models. Hence, it can be stated that the developed building penetration path loss model can be used to accurately predict signal attenuation in buildings located in an urban environment.

Minerals: A Very Short Introduction. By David J. Vaughan. Oxford University Press, 2014. Paperback, Pp. 160. Price GBP 7.99. ISBN 9780199682843.

Nowadays, interest in minerals is widespread and the results of mineral sciences are a necessary background not only in classical Earth science but also in materials, biological, forensic, geophysical and other branches of sciences. The author is well known for his ‘molecular scale studies of mineral surfaces including interactions with microbial species, and applications of such studies to problems of Earth resources (including mineral extraction technologies) and the environment’, as one can read on the web site of the School of Earth, Atmospheric and Environmental Sciences at the University of Manchester (http://www.seaes.manchester.ac.uk/people/staff/profile/?ea=david. vaughan). In this pocket book David J. Vaughan has done an outstanding job presenting complex notions in simple terms and providing examples to which the reader can relate. Following his research interests, he combines classic mineralogy together with aspects such as the role of minerals in the living world and environment, going through modern aspects of analytical methods. The output is an unconventional but very appealing presentation of mineralogy aimed at the amateurs and anyone interested in minerals, even if some basic knowledge of chemistry and physics is required. This introduction to mineralogy could also be a quick and easy lecture for those students looking for inspiration to focus their attention on different aspects of modern mineral sciences. The book, well illustrated with greyscale drawings and images, is divided into seven chapters, and throughout terms are defined in an exhaustive way. Unfortunately, any colour image is used to better illustrate thin section photos, crystal structures and geological sketches; the quality of the book would have been improved using a few colour images. The first chapter presents the basics of mineralogy and crystallography. It serves as a quick refresher if the reader’s notions of mineralogy are rusty. Chapter 2 reviews analytical methods currently used to characterize mineral species, going from the principle of classic polarizing microscopy to more recent and powerful techniques, such as electron microscopy; some principles of X-ray diffraction and spectroscopy are also refreshed. Chapter 3 is a very short course on geodynamics, relating minerals to their genesis and their impact on different tectonic environments; a short part is dedicated to high-pressure experiments that allow scientists to understand the behaviour of minerals under conditions not directly accessible, such as those occurring in the Earth’s interior. Chapter 4 introduces the cycling of minerals at, or very near, the surface of the Earth, particularly under weathering conditions. This is used as a starting point to present the latest frontiers of mineral sciences touching biological and environmental aspects, such as the role of nano-particles, nano-minerals and aerosols, including their peculiar physical and chemical properties in terms of surface and interface interactions. Chapter 5 approaches other very relevant and fashionable arguments, such as biominerals and bio-mineralogy. The author’s approach is extremely clear and the descriptions of how the biological world (organisms) can produce mineral phases not belonging to the classic geological processes are clearly defined. Chapter 6 discusses minerals as resources, taking into consideration all the major aspects of different mineral sources and properties, how mineral deposits form and how and why these resources are exploited. ISSN 2052-5206

Planar Sauter Mean Diameter measurements in liquid centered swirl coaxial injector using Laser Induced Fluorescence, Mie scattering and laser diffraction techniques

An experimental technique is carried out to demonstrate the measurement of planar Sauter Mean Diameter (SMD or D32) distribution in a liquid centered swirl coaxial injector (LCSC) using simultaneous measurements of Mie scattering, Planar Laser-Induced Fluorescence (PLIF) and Laser diffraction technique (LDT). Here water is used as the test fluid with addition of optimized quantities of the organic dye (Rhodamine 6g) for PLIF measurements. Experiments are carried out at three experimental conditions with momentum flux ratios of 6.25, 12.14, and 19.95 respectively. Experiments are carried out to study the effect of dye concentration in LDT. LDT (line of sight) is corrected for multiple scattering effects. The SMD distribution obtained from Liquid Sheet Drop Sizing (LSDS) technique is calibrated using LDT (Malvern particle analyzer) that utilizes the principle of diffraction; the results obtained from both the methods are compared and analyzed using the respective histograms. The variations in the distribution of droplet diameter along the axial and radial locations in the spray field are also studied in detail.

Color Tuneable Bio-Sensor Made Up From Stimuli-Responsive Nanoparticles

A biosensor is a device that is made up of transducer and biological elements [1-3]. The biological elements can be proteins, enzymes or antibodies [1]. The biological elements interact with the analyte which convert the biological response to an electrical signal. So usually biosensor consists of a biological component (acting as a sensor) and an electrical component (for detecting and transmitting the signal). Biosensors have a wide range of applications in different areas of science such as health care industry, clinical analysis and diagnosis of disease and agriculture [4]. In particular, there is a growing interest to prepare bio-sensor using different types of nanomaterials such as gold nanoparticles, carbon nanotubes, quantum dots, etc. [4].In the current proposal, we plan to prepare a low cost protein-sensor using polymeric stimuli-responsive nanoparticles based on diffraction principle. Moreover, this sensor will have a switchable functionality towards pH, temperature and electric field and also can be used with high accuracy of proteins detection based on a simple diffraction principle in the visible region. Since the awareness regarding health and wellbeing is increasing day by day in the global population, the use of biosensors in diagnostics is also simultaneously growing. Thus we believe that our proposed protein sensor based on diffraction principle will also have a popular demand in health care industry.

N‐Rich Fused Heterocyclic Systems: Synthesis, Structure, Optical and Electrochemical Characterization

AbstractA new class of N‐rich fused heterocyclic compounds containing the triazolo‐triazine moiety was synthesized and studied by cyclic voltammetry, UV/Vis spectroscopy, X‐ray diffraction, and first principle computations. All the compounds show reversible or quasi‐reversible reduction processes, with reduction potentials easily tunable within the class. LUMO energies as low as –3.95 eV have been measured. The UV/Vis spectra show highly structured absorptions, indicative of rigid molecular skeletons. The solid‐state packing is dominated by π–π stacking interactions, which are promoted by weak CAr–H···N interactions, whereas face‐to‐edge contacts (T contacts), typical of many fused hydrocarbons, are largely absent.

Strength Development and Physical Properties of Cement Paste with Incorporated Ceramic Powder

A possible usage of fine waste ceramic powder coming from precise brick cutting in production of blended cement is analyzed in the paper. For the studied ceramic powder, chemical and mineralogical composition is measured by X-Ray Fluorescence and X-Ray Diffraction. The particle size distribution of ceramic powder is accessed on laser diffraction principle. The ceramic powder is used in cement based pastes composition in cement mass replacements of 8, 16, 24, 32, and 40%. For the tested pastes, monitoring of strength development is done using measurement of time dependent mechanical parameters. Bulk density, matrix density, and total open porosity are measured for 28 days cured samples. In order to obtain information on the rate of hydration process, the formation of pastes’ solid structure is monitored using measurement of pore size distribution at chosen times of hydration. Application of waste ceramics is found to give the most promising mechanical properties of the cement-based paste for 8 and 16% cement replacement levels what makes good prerequisites for future research that will be focused on design and development of new types of cement-based composites with incorporated ceramic waste powder. However, also other tested mixtures provide acceptable results. This knowledge can be used for instance in the production of lower strength composites.

Low-Contrast Dielectric Metasurface Optics

The miniaturization of current image sensors is largely limited by the volume of the optical elements. Using a sub-wavelength patterned quasi-periodic structure, also known as a metasurface, one can build planar optical elements based on the principle of diffraction. However, it was believed that high refractive index materials are required for metasurface optics. Here, we show that one can employ the design principles of a metasurface even with low contrast materials, such as silicon nitride. We validate our theory by fabricating and experimentally characterizing several silicon nitride based lenses and vortex beam generators . The fabricated lenses achieved beam spots of less than 1 {\mu}m with numerical apertures as high as ~ 0.75. A transmission efficiency of 90% and focusing efficiency of 40% in the visible regime was observed. Our results pave the way towards building low-loss metasurface based optical elements at visible frequencies using low contrast materials.

Anomalous magneto-elastic and charge doping effects in thallium-doped BaFe2As2.

Within the BaFe2As2 crystal lattice, we partially substitute thallium for barium and report the effects of interlayer coupling in Ba1-xTlxFe2As2 crystals. We demonstrate the unusual effects of magneto-elastic coupling and charge doping in this iron-arsenide material, whereby Néel temperature rises with small x, and then falls with additional x. Specifically, we find that Néel and structural transitions in BaFe2As2 (TN = Ts = 133 K) increase for x = 0.05 (TN = 138 K, Ts = 140 K) from magnetization, heat capacity, resistivity, and neutron diffraction measurements. Evidence from single crystal X-ray diffraction and first principles calculations attributes the stronger magnetism in x = 0.05 to magneto-elastic coupling related to the shorter intraplanar Fe-Fe bond distance. With further thallium substitution, the transition temperatures decrease for x = 0.09 (TN = Ts = 131 K), and this is due to charge doping. We illustrate that small changes related to 3d transition-metal state can have profound effects on magnetism.

Properties of Cement Paste with Incorporated Sodium Silicate

Sodium silicate, usually known as water glass, is researched as material that can potentially find use in composition of cement based matrix in order to improve its porous structure and related physical parameters. The water glass is applied in cement paste mixture in an amount of 5, 10, 15, and 20 mass% of cement. The water dosage is experimentally accessed in order to attain the same workability of particular mixtures. For the applied water glass and cement, the particle size distribution is measured on laser diffraction principle. Pozzolanic activity of water glass is investigated using modified Chapelle test. The particular studied cement pastes are cured 28 days in water and characterized by basic physical and mechanical properties, whereas the results of mechanical resistivity are supported by pore size distribution data accessed by mercury intrusion porosimetry. Althought the particles of applied water glass are coarser than that of cement and did not exhibit pozzolanic activity, their application partially tightened the porous structure of hydrated products and thus contributed to the mechanical strength by means of filler effect. This makes good prerequisites for future research that will be focused on a development of new types of cement-based composites with incorporated sodium silicate used as an modifying admixture.

OPTIMIZATION ON WIRELESS POWER TRANSFER

Today, the limit of wireless devices lays in the way they powered. There has been a renewed focus on wireless power transmission technology due to its wide range of application in charging electronic devices such as mobile, MP3 player and household robots without a cord. Imagine a device that doesn't need a charger or even a battery, which instead gets power wirelessly over the air. To make such a device possible the transfer distance of currently known system have to be increased. The wireless power transfer can be optimized base on Friis equation. The Friis transmission equation is developed from principle of optical radiometry and scalar diffraction. Friis equation will gives the amount of power an antenna received under ideal conditions from another antenna.

Development of 3D Measurement System Using Phase Shift Digital Holography

SUMMARYThe demand for three‐dimensional (3D) measurement technology has been increasing, but in many of the traditional 3D measurement methods, such as the method using phase shift pattern projection, it is difficult to measure the shape of specular‐reflective and transparent objects, because the power of the light reflected from specular reflective objects is too high and that from transparent objects is too low. Consequently, digital cameras cannot acquire accurate information from reflected light. Digital holography has been used as a means of resolving this problem. In traditional digital holography, the interference fringes of the light from the object being measured and the reference light can be captured by a digital camera. Using the Fresnel diffraction principle, the phase information in the light from the object being measured can be acquired and the shape of the object can be calculated by interferometry. Digital holography can be used to measure reflective and transparent objects. However, by the principle of Fresnel diffraction, dc and conjugate components exist in the calculated phase information a noises, so that the accuracy of measurements is reduced. Phase shift digital holography can remove noise by using special devices to change the phase of the reference light, but the devices are costly and the systems are complex, so that practical application of phase shift digital holography has been difficult. In this paper, we propose a new method of phase shift digital holography using the light detection principle. We also propose a digital holography reconstruction method using the convolution approach rather than the traditional Fresnel approach. The proposed method results in a compact phase shift holography system with lower cost and greater accuracy than the 3D measurement method. Therefore, the practical applications of digital holography can be realized less expensively and more accurately.

Development of an ultra-miniaturised XRD/XRF instrument for the in situ mineralogical and chemical analysis of planetary soils and rocks: implication for archaeometry

An ultra-miniaturised (mass 1.5 kg; volume ~22 × 6 × 12 cm3) instrument which combines X-ray diffraction and fluorescence has been developed for the mineralogical and chemical characterization of Martian soils/rocks and was included in the ExoMars-Pasteur payload. The simultaneous in situ acquisition of elemental and mineralogical information would significantly improve any robotic missions and may unravel doubtful points regarding the mantle composition, crustal evolution and resource potential. The instrument employs a fixed reflection geometry to fulfil the diffraction principle which can be applied to unprepared sample as well. The instrument basically consists of a radioisotope as source of X-rays and a CCD-based detection system. This is the first successful diffraction experiment using a radioisotope since the early tests in the 60s. For terrestrial application the radioisotope can be easily replaced with a cathodic tube. The reduced dimension as well as the possibility to perform non-destructive analysis makes it suitable for terrestrial applications, particularly in the archaeometry field. We are envisaging an X-ray tomographer to map the mineralogical and elemental composition of an artefact (i.e., painting, pottery) directly on the object without sample preparation. Nowadays, X-ray radiography or computer tomography are becoming standard techniques widely used and accepted by art historians, archaeologists, curators and conservators as these methods enable information about the manufacturing process and the condition of an object without touching the artefact or even taking original sample material.

Ceramic Waste Powder as an Active Pozzolanic Material for Cement Based Composites

Parameters of cement pastes with ceramic powder as partial Portland cement replacement up to 40 mass% are presented in the paper. Ceramic powder belongs to the pozzolanic materials. Utilization of pozzolanic materials is accompanied by lower request on energy needed for Portland clinker calcination which generally results in lower production costs of blended binder and lower CO2 emissions. The ceramic powder is used in cement based pastes composition in amount of 8, 16, 24, 32, and 40 mass% of cement. For the studied ceramic powder, chemical composition is measured by X-Ray Fluorescence. The particle size distribution of ceramics is accessed on laser diffraction principle. Bulk density, matrix density, and total open porosity are measured for 28 days cured paste samples. The obtained results demonstrate that ceramic powder has potential to replace a part of Portland cement in composition of cement based composites.

Physical and Mechanical Properties of Cement Pastes with Blended Binder Containing Fine Milled Glass

Physical and mechanical behaviour of cement pastes with partial Portland cement replacement by fine milled waste glass is researched in the presented paper. The tested pastes contain milled borosilicate glass in amount of 5, 10, 20, and 30 mass% of cement. The chemical composition of borosilicate glass and used Portland cement is accessed by XRF (X-Ray Fluorescence) analysis. For the milled glass, pozzolanic activity and particle size distribution are measured. Here, modified Chapelle test is used for evaluation of pozzolanic activity. Particle size distribution is measured on laser diffraction principle. Basic physical properties and mechanical properties are determined for samples cured 28 and 90 days in water in order to evaluate the kinetics of hydration process. The obtained results revealed the possible applicability of the tested borosilicate glass in the composition of cement-based composite materials.

Interpretation of azimuthal angle dependence of periodic gratings in Mueller matrix spectroscopic ellipsometry.

Mueller matrix spectroscopic ellipsometry becomes increasingly important for determining structural parameters of periodic line gratings. Because of the anisotropic character of gratings, the measured Mueller matrix elements are highly azimuthal angle dependent. Measurement results are interpreted by basic principles of diffraction on gratings. The spectral and azimuthal angle dependent intensity changes are correlated to so-called Rayleigh singularities, i.e., wavelengths where the number of diffraction orders changes. The positions of the Rayleigh singularities are calculated analytically and overlapped with measured spectra of two different types of photomasks with transparent and reflecting substrates. For both types of gratings, the Rayleigh singularities reproduce the contours of the spectra. Increasing grating periods result in a shift of these contours to longer wavelengths. Characteristic differences between the two photomasks are explained by the influence of the transmission orders, which are determined by the substrate transparency.

Thermal Behaviour of New Type of Plaster with PCM Admixture

In order to decrease the energy consumption of buildings and keep the high thermal comfort of the indoor environment, new types of plasters modified by phase change material (PCM) are developed and experimentally tested. For evaluation of the contribution of PCM admixture to plasters properties, the reference plaster is studied as well. The basic characterization of the tested plasters is done using the measurement of their bulk density, matrix density a total open porosity. For the dry plasters mixtures, the particle size distribution is accessed on laser diffraction principle. Investigation of thermal properties as main parameters affecting the thermal performance of researched materials is done by differential scanning calorimetry (DSC) and transient impulse method. The obtained results proved increased heat storage capacity of the newly developed plasters with incorporated PCM admixture.

In situ high-energy synchrotron X-ray diffraction studies and first principles modeling of α-MnO2 electrodes in Li–O2 and Li-ion coin cells

In situ synchrotron diffraction and first principles modeling shows structural changes in α-MnO2 during cycling in Li–O2 battery cells, as lithium and oxygen are incorporated into and removed from tunnels in the structure.

Characterization of Cement Pastes Containing Natural Zeolite as a Pozzolanic Admixture

A possible use of natural zeolite originating from a mining area in South Slovakia as a pozzolanic material suitable for the partial cement replacement in composite production is studied. Measurement of chemical composition of natural zeolite is performed using XRF analysis. The particle size distribution of zeolite and dry paste mixtures is accessed on laser diffraction principle. For the tested pastes, basic physical properties and mechanical properties are determined. The obtained results indicate a good potential for the application of natural zeolite in the composite mix design.