Biochemical composition and quality of herring preserves with addition of bio-protective cultures

Herrings rich in vitamins B12, A, D, minerals, including calcium, potassium, magnesium, iodine, possess high levels of lysine, tyrosine, phenylalanine and tryptophan, as well as omega-3 unsaturated fatty acids, namely eicosapentanoic, docosahexoenoic and docosapentoenoic. To suppress the microbiological spoilage of fish preserves, it is promising to use bio-protective cultures that have minimal impact on the production process and product properties. Bacterial strains are able to exert a static effect on the microflora, which causes biodeterioration of food products. Microorganisms as part of bio-protective cultures are included in the fermentation process, so they can be attributed to ordinary food ingredients, so there is no need to put separate information on the packaging. The chemical composition of the frozen Atlantic and Pacific herring fillet, the amino acid composition of proteins, and the fatty acid composition of lipids were studied. The difference between Atlantic and Pacific herrings was detected, which consists in a significantly higher content of docosahexaenoic acid. The difference in the fractional composition of triacylglycerols for the Atlantic and Pacific herring was established. The microflora of SafePro B-2 biological product (Chr. Hansen GmbH), containing multiple strains of Lactobacillus sakei, and the viability of the culture in preserves fillings were studied. The experimental development of canned food with SafePro B-2 additives was carried out. Microbiological, organoleptic and biochemical indicators of the preserves quality during cold storage were studied. The influence of introduced culture on the dynamics of preserves curing period and their shelf life was established

Optical vector network analysis of ultra-narrow transitions in 166^{166}Er3+^{3+}:7^7LiYF4_4

We present optical vector network analysis (OVNA) of an isotopically purified $^{166}$Er$^{3+}$:$^7$LiYF$_4$ crystal. The OVNA method is based on generation and detection of modulated optical sideband by using a radio-frequency vector network analyzer. This technique is widely used in the field of microwave photonics for the characterization of optical responses of optical devices such as filters and high-Q resonators. However, dense solid-state atomic ensembles induce a large phase shift on one of the optical sidebands which results in the appearance of extra features on the measured transmission response. We present a simple theoretical model which accurately describes the observed spectra and helps to reconstruct the absorption profile of a solid-state atomic ensemble as well as corresponding change of the refractive index in the vicinity of atomic resonances.Comment: 4 pages, 5 figure

Professional competency and health student

Analysis result studies is presented In article on problem of health and sound lifestyle student, is determined role of the physical culture, pulpits of the physical culture in this process, is intended way to activations resource educational space of the university for decision given problems using kompetention approachВ статье представлен анализ результатов исследований по проблеме здоровья и здорового образа жизни студентов, определена роль физической культуры, кафедры физической культуры в этом процессе, намечены пути активизации ресурсов образовательного пространства университета для решения данной проблемы c применением компетентностного подход

Digital simulators of the random processes

The proposed universal digital simulators of random processes based on their Markov models are considered as capable of generating sequences of samples of unlimited duration. It is shown that a simple Markov chain allows generating the random numbers with a specified two-dimensional probability distribution of the neighboring values while a doubly connected Markov model makes it possible to get the three-dimensional random numbers. The parameters of the model are determined from either a known probability density or experimental samples of the simulated random process. It is demonstrated that the simulation algorithms do not require complex mathematical transformations and that they can be implemented using a simple element base. To change the properties of the generated random processes one needs to reload the memory device with a preformed data array. The block diagrams of the simulators are studied and the probabilistic and correlation characteristics of the generated random processes are determined. It is established that with these simulators a high accuracy of convergence of the probability distributions of the selected model and the histograms of the generated sample sequences is ensured. In the common studies, one can hardly find the results that can surpass by their efficiency the ones that the proposed simulation algorithms demonstrate accounting for their non-problematic hardware implementation (the minimum computational costs) and the simplicity of reconfiguring the Markov model based simulators for generating new random processes. The introduced simulators can be used in the design, development and testing of the multi-purpose electronic equipment, with different meters and the devices for simulating radio paths

All-solid-state subnanosecond tunable ultraviolet laser sources based on Ce3+-activated fluoride crystals

Several practical all-solid-state tunable ultraviolet subnanosecond laser sources have been developed based on Ce3+:LiLuF4 (Ce:LLF) and Ce3+:LiCaAlF6 (Ce:LiCAF) active media pumped by the fifth and fourth harmonics of a regular Q-switched 10-ns Nd:YAG laser, respectively. The demonstrated tuning range of the Ce:LiCAF oscillator providing reproducibly-single-pulse output was 282 nm to 314 nm with the maximum output energy of 1 mJ. Tunable laser output from 223 nm to 232 nm was obtained by sum-frequency-mixing Ce:LiCAF laser output with fundamental output of a Q-sw Nd:YAG laser. The maximum subnanosecond Ce:LiCAF single-pulse output of 14 mJ was obtained in a "master oscillator-power amplifier" (MOPA) configuration

The analysis of spin hamiltonian and crystal field tensors for Fe3+ in crystals of LiCaAlF6 and LiSrAlF6

In single crystals of LiCaAlF6 and LiSrAlF6 doped with Fe3+ the trigonal EPR spectra with multiplicity KM = 1 were observed due to Fe3+ substituted for Al3+. The spin Hamiltonian parameters describing the fine structure and the superhyperfine structure were determined. It is argued that the tensors B2 and BA of the spin Hamiltonian for Fe3+ ions are essentially determined by the quadratic contributions of the crystal field at the substitution site. The signs and the relative values of the elements in the spin Hamiltonian tensor B4 of rank L = 4 for Fe3+ are determined by the irreducible tensor product [V4⊗V4]2 of the crystal field tensor V4 of rank L = 4 at the substitution sites. The ratio between the invariant sum of the spin Hamiltonian tensor B4 for Fe3+ in oxygen octahedra [FeO6] and that in fluorine octahedra [FeF6] is directly proportional to the fourth power of the ratio between the effective charges of surrounding ions. The sign of the spin Hamiltonian parameter B20 corresponds to the sign of the element [V4⊗V4]20 in the irreducible tensor product [V4⊗V4]2 of rank L = 2. © Springer-Verlag 1998

Strongly anisotropic magnetocaloric effect in a dipolar magnet LiGdF4_4

We report the detailed study of the magnetocaloric effect (MCE) in a dipolar-Heisenberg magnet LiGdF$_4$ using magnetization measurements performed on a single crystal sample. Entropy variation on isothermal demagnetization from the magnetic field up to 3 T is determined in the temperature range 2-10 K for two principal directions of the applied field (parallel and perpendicular to the tetragonal $c$-axis of the crystal). The MCE is found to be highly anisotropic, with the cooling efficiency being up to twice higher at $H\parallel c$. The results are nicely interpreted in the frame of a conventional molecular field approach taking into account considerable anisotropy of the paramagnetic Curie-Weiss temperature. These results are compared to earlier studies of MCE in powder samples of LiGdF$_4$ [T. Numazawa et al., AIP Conf. Proc. 850, 1579 (2006)] as well as with analogous data for other well known magnetocaloric materials. Our findings may open new possibilities to enhance the efficiency of magnetic refrigeration in the liquid helium-4 temperature range.Comment: 4 pages, 3 figure

Microscopic spin Hamiltonian for a dipolar-Heisenberg magnet LiGdF4 from EPR measurements

Low-temperature electron paramagnetic resonance measurements are performed on single crystals of LiY_{1-x}Gd_xF_4 with weak x=0.005 and moderate x=0.05 concentration of Gd ions. Modeling of the experimental spectra allows us to precisely determine microscopic parameters of the spin Hamiltonian of the parent LiGdF4 material, including the nearest-neighbor exchange constant. The obtained parameters are further tested by comparing a strongly anisotropic Curie-Weiss temperature obtained for LiGdF4 in our static magnetization measurements with theoretically computed values. We find a fine balance between principal magnetic interactions in LiGdF4, which results in a hidden magnetic frustration presumably leading to a delayed magnetic ordering and an enhanced magnetocaloric effect at low temperatures.Comment: 6 pages, 6 figure

All-solid-state tunable ultraviolet subnanosecond laser with direct pumping by the fifth harmonic of a Nd:YAG laser

We report what we believe is the first all-solid-state tunable ultraviolet laser pumped by the fifth harmonic of a Q-switched Nd:YAG laser. Our laser based on a Ce3+:LiLuF4 active medium stably generates a single, satellite-free, 0.88-ns pulse under 5-ns, 10-Hz repetition rate pumping conditions. A novel tilted-incident-angle side-pumping scheme resulted in a simple laser-cavity design. © 1998 Optical Society of America

EPR of Gd3+ in single crystal colquiriite and analysis of the spin Hamiltonian tensors B4 and B6

In single crystal colquiriite LiCaAlF6 doped with Gd3+ ions two EPR spectra of the Gd3+ ions with the Laue site-symmetry groups Ci and C3i were observed. The spectrum angular dependence for trigonal Gd3+ centre was investigated in detail and corresponding spin Hamiltonian parameters were fitted. From analysis of the spin Hamiltonian tensors B4 and B6 it was established that Gd3+ with the Laue group C3i substitutes at Ca2+ site with the excess charge compensation by an ion located along the threefold axis from this site. The transformation formulas for a sixth-rank irreducible Hermitian tensor under coordinate rotation are tabulated in an explicit form. By using the EPR data for Gd3+ substituted in a variety of host crystals, the fourth-rank and sixth-rank tensors of Gd3+ spin Hamiltonians were tabulated and correlated with structures of the coordination polyhedra at substitution sites. The results suppose a predominance of quadratic crystal field contributions into the spin Hamiltonian tensor B4 of Gd3+. © Springer-Verlag 1997