Illustration of X-ray photography of a rotating crystal with the aid of centimeter electromagnetic waves

1969 ◽  
Vol 97 (4) ◽  
pp. 738-741
Author(s):  
N.Ya. Molotkov
Keyword(s):  
2010 ◽  
Vol 75 ◽  
pp. 230-239
Author(s):  
Herbert O. Moser ◽  
Linke Jian ◽  
Shenbaga M.P. Kalaiselvi ◽  
Selven Virasawmy ◽  
Sivakumar M. Maniam ◽  
...  

The function of metamaterials relies on their resonant response to electromagnetic waves in characteristic spectral bands. To make metamaterials homogeneous, the size of the basic resonant element should be less than 10% of the wavelength. For the THz range up to the visible, structure details of 50 nm to 30 μm are required as are high aspect ratios, tall heights, and large areas. For such specifications, lithography, in particular, synchrotron radiation deep X-ray lithography, is the method of choice. X-ray masks are made via primary pattern generation by means of electron or laser writing. Several different X-ray masks and accurate mask-substrate alignment are necessary for architectures requiring multi-level lithography. Lithography is commonly followed by electroplating of metallic replica. The process can also yield mould inserts for cost-effective manufacture by plastic moulding. We made metamaterials based on rod-split-rings, split-cylinders, S-string bi-layer chips, and S-string meta-foils. Left-handed resonance bands range from 2.4 to 216 THz. Latest is the all-metal self-supported flexible meta-foil with pass-bands of 45% up to 70% transmission at 3.4 to 4.5 THz depending on geometrical parameters.


2021 ◽  
Vol 7 (28) ◽  
pp. eabf0851
Author(s):  
Zhonghua Yao ◽  
William R. Dunn ◽  
Emma E. Woodfield ◽  
George Clark ◽  
Barry H. Mauk ◽  
...  

Jupiter’s rapidly rotating, strong magnetic field provides a natural laboratory that is key to understanding the dynamics of high-energy plasmas. Spectacular auroral x-ray flares are diagnostic of the most energetic processes governing magnetospheres but seemingly unique to Jupiter. Since their discovery 40 years ago, the processes that produce Jupiter’s x-ray flares have remained unknown. Here, we report simultaneous in situ satellite and space-based telescope observations that reveal the processes that produce Jupiter’s x-ray flares, showing surprising similarities to terrestrial ion aurora. Planetary-scale electromagnetic waves are observed to modulate electromagnetic ion cyclotron waves, periodically causing heavy ions to precipitate and produce Jupiter’s x-ray pulses. Our findings show that ion aurorae share common mechanisms across planetary systems, despite temporal, spatial, and energetic scales varying by orders of magnitude.


Author(s):  
Engkir Sukirman ◽  
Yosef Sarwanto ◽  
Andon Insani ◽  
Wisnu Ari Adi ◽  
Yose Fachmi Buys

The weak ferromagnetic property and the electromagnetic waves absorption characteristic of La(1-x)BaxMnO3 (LBMO) compounds have been investigated. The samples of LBMO that are LaMnO3 (S0), La0.9Ba0.1MnO3 (S1); La0.8Ba0.2MnO3 (S2); and La0.7Ba0.3MnO3 (S3) were synthesized using high energy milling (HEM) method. Samples were characterized by means of XRD (X-ray diffractometer), HRPD (high-resolution powder neutron diffractometer), EDS (energy dispersive X-ray spectroscopy, VSM (vibrating sample magnetometer), and VNA (vector network analyzer). There is no magnetic ordering of ferromagnetic in S1 and S2 samples due to the Ba occupation factors of both less than 0.2. The Ba content in the S3 sample is greater than 0.2, hence the ferromagnetic property of the compound is not so visible with the VSM as well as the VNA. The absorption characteristics of electromagnetic waves using VNA indicated that there is an absorption of EM waves in the frequency range between 8-12 GHz with almost the same peak frequency for all four samples at 10.8 GHz with the absorption of around 5 dB. The existence of a weak ferromagnetic property can be detected clearly using HRPD. Neutron diffraction as a probe can observe the magnetic structure accurately even in a material having a weak ferromagnetic property.


2017 ◽  
Vol 18 (4) ◽  
pp. 431-437 ◽  
Author(s):  
L. Sysa ◽  
L. Shevchuk ◽  
A. Kontsur

The adsorption isotherms of nickel ions from aqueous solutions on bentonite, a natural argillaceous material, previously prepared using ultrahigh-frequency electromagnetic waves ("microwaves") were researched in the article. The phase composition of the sorbent was studied by applying the X-ray powder method. Bentonite sample being pre-wetted and irradiated by microwaves shows 2.7 times better sorption properties than the untreated (native) sample, which was shown on the example of the adsorption process of nickel ions from model solutions in static conditions. The sorption parameters prepared by using the "microwaved" and the native samples of bentonite were calculated according to the Langmuir adsorption equations. The barrier density of nickel in the irradiated sorbent is 16.4 mg/g (0.28 mmol/g), whereas for native bentonite the value of the analogous parameter is 6.0 mg/g (0.10 mmol/g). The reason for such an increase in sorption properties may be the change in the crystalline structure and distribution of micropores on the surface of the sorbent under the action of "microwaves" in the aqueous medium. The determinants in the pre-preparation of sorbent by "microwaves" are the ultimate power and time of irradiation. 


Author(s):  
Seda V. Marutyan ◽  
Gayane H. Petrosyan ◽  
Syuzan A. Marutyan ◽  
Liparit A. Navasardyan ◽  
Armen H. Trchounian

In metabolism of living cells a key role play purine nucleotides which cells can be supplied either by de novo synthesis from lower molecular weight precursors, or by alternate ways of nucleotide synthesis or so-called "nucleotide salvage pathways", which allow reusing of intermediate products of nucleotide metabolism in nucleotide synthesis. This way is important in the post-stress repair period, saving energy and substrates in the repairing cells. Purine nucleotides are allosteric inhibitors of enzymes of nucleotide salvage pathways, therefore the increase in their catabolism leads to a decrease of their amount in the cells, which contributes to the intensive work of the nucleotide salvage pathways and provides substrates for DNA synthesis. Investigation of deamination of purine nucleotides in yeasts Candida guilliermondii NP-4 irradiated with X-rays, millimeter and decimeter electromagnetic waves, as well as after post-radiation incubation of cells has been realized. It has been shown that under the influence of X-ray and microwave irradiation in yeasts, the intensity of deamination of purine nucleotide-polyphosphates - ADP, ATP, GDF and GTP, has changed, which in all probability is an adaptive mechanism in the repair of yeasts after irradiation, provides the work of nucleotide salvage pathways, and can be associated with the metabolism of these compounds.


Radiotekhnika ◽  
2020 ◽  
pp. 181-185
Author(s):  
A.I. Kozar

A solution is given to the problem of scattering of electromagnetic waves by a discrete convex polyhedron – an octahedron of resonant magnetodielectric spheres based on a complex rhombic crystal lattice. Here we consider a case equivalent to the X-ray optics of crystals, when α / λ՛<<1 and can be α / λg ~ 1; d, h, l / λ՛ ~ 1, where α is the radius of the spheres; λ՛, λg are the lengths of the scattered wave outside and inside the spheres; d, h, l are constant lattices. The solution of the problem is obtained based on the Fredholm integral equations of electrodynamics of the second kind with nonlocal boundary conditions. The expressions found in this work for a metacrystal in the form of an octahedron can be used to study the fields scattered by the crystal in the Fresnel and Fraunhofer zones, as well as to study its internal field. The relations obtained in this work can find application in the study of the scattering of waves of various kinds by convex polyhedrons, the creation on their basis of new types of limited metacrystals, including nanocrystals with resonance properties, and in the study of their behavior in various external media. As well as in the development of methods for modeling electromagnetic phenomena that can occur in real crystals in resonance regions in the optical and X-ray wavelength ranges.


2013 ◽  
Vol 552 ◽  
pp. 75-78
Author(s):  
Miang Zhao Ouyang ◽  
Yue Gang Fu ◽  
Zhi Ying Liu ◽  
Jia Ke Wang ◽  
Wen Jun He

As an ultra-short electromagnetic waves, X-ray has a strong ability to penetrate with high-energy. The method for focusing visible spectral bands is not suitable for X-ray spectrum. At present, in X-ray astronomy, the X-ray focus mode which uses grazing incidence less than critical angle has been widely used. However, the small critical angle limits its effective aperture of the X-ray collection. This paper presents a multi-layer reflective structure working with grazing incidence and the surfaces coated multilayer high reflective for X-ray. It can guarantee the large effective entrance pupil and high energy collection. The 200mm diameter X-ray focusing device is designed as an example. It is found from simulation that a good focusing result is acquired.


1986 ◽  
Vol 30 ◽  
pp. 7-11
Author(s):  
H. Ebel

The European contributions to X-ray fluorescence analysis (XRF) have shown remarkable fluctuations with regard to time and can be divided into three groups, each of them covering about thirty years.At the beginning there was the discovery of X-rays by Röntgen in 1895. He received the first Nobel Prize in physics (1901). Barkla (Nobel Prize in physics 1917) gave a description of the interaction of X–rays with matter–scattering (1904) and polarization (1906), absorption (1909) and fluorescence (1911). In 1912 the crucial experiment of Friedrich, Knipping and von Laue brought the confirmation on the nature of X–rays as part of the spectrum of electromagnetic waves (Nobel Prize in physics 1914).


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