Дельта-моделі коливальних структур та смугових фільтрів

Introduction. Oscillatory circuits and resonant sections of transmission line (TL) are the basic signals frequency filtering structures. Oscillatory circuits belong to lumped oscillatory structures with one resonant frequency. A set of connected one-resonant oscillatory structures forms a structure with several resonant frequencies used in band-filtering. In various scientific and technical areas the approach based on $\delta$-functions is widely used for simulation. In the presented paper the approach based on $\delta$-models expand on oscillatory structures and bandpass filters. Delta-models of oscillatory structures. Models of oscillatory circuits and resonant TL sections as impedance resonant δ -inhomogeneities are proposed. These models are called δ-models. It is shown that resonant δ-barrier is equivalent to series oscillatory circuit and resonant δ-well - to parallel oscillatory circuit. Resonance δ-inhomogeneities are characterized by three parameters - direction determining the resonance nature (series or parallel), its own resonant frequency and parameter directly proportional to the quality factor. Comparison of TL resonant section and δ-model characteristics. TL section and δ-model frequency characteristics are compared. It is shown that with increasing of the difference between transmission line and section impedances section characteristic approaching δ-model characteristic. Delta models of coupled resonant structures. Delta-models of coupled oscillatory circuits are presented. Comparison of transmission coefficient of two coupled δ-models with frequency response of two identical coupled circuits illustrate their accordance. Delta models of bandpass filters. Delta-models of bandpass filter formed by series and parallel oscillatory circuits are presented. Delta models simplify filter analysis and for the filter with quarter-wave links between oscillatory structures allow finding a solution with fewer quality factor values and lower quality factor maximum, which simplifies filter design. Conclusion. The proposed δ-models of oscillatory structures in the form of resonant impedance δ-heterogeneities allows to simulate single lumped and distributed oscillatory structures, coupled oscillatory structures, and also filters on their basis. Delta models simplify the analysis of oscillatory structures and filters and, as in the case of reactive elements δ-models, "prompt" new filter solutions; in the case considered with improved constructive parameters.Предложены модели колебательных контуров, резонансных отрезков длинной линии и полосовых фильтров, названные δ-моделям. Выполнено сравнение резонансных характеристик отрезка длинной линии и δ-модели. Рассмотрены δ-модели и частотные характеристики связанных колебательных структур и полосовых фильтров.Запропоновано моделі коливальних контурів, резонансних відрізків довгої лінії та смугових фільтрів, названі δ-моделями. Виконано порівняння резонансних характеристик відрізка довгої лінії та δ-моделі. Розглянуто δ-моделі та частотні характеристики зв’язаних коливальних структур та смугових фільтрів

Properties of ZnO/ZnAl2_2O4_4 composite PEO coatings on zinc

Recently the successful formation of PEO coatings on zinc in a phosphate aluminate electrolyte was shown. The produced composite coatings contain various mixtures of ZnO and ZnAl$_2$O$_4$. In frame of the current study, the properties of the formed coatings including adhesion/cohesion, wear, corrosion and photocatalytic activity were analysed to identify possible applications. However, the coatings show internal porosity and a sponge-like structure. Thus the cohesion within the coating is quite low. Pull-off tests have demonstrated clear rupture within the PEO layer at strength values as low as 1 MPa. The photocatalytic activity is limited, in spite of the formation of a higher amount of ZnO at shorter treatment times. Interestingly, the composite coatings of ZnO and higher amounts of ZnAl$_2$O$_4$ spinel showed a higher activity, but not sufficient for fast and effective catalytic cleaning applications

Human-specific histone methylation signatures at transcription start sites in prefrontal neurons

Cognitive abilities and disorders unique to humans are thought to result from adaptively driven changes in brain transcriptomes, but little is known about the role of cis-regulatory changes affecting transcription start sites (TSS). Here, we mapped in human, chimpanzee, and macaque prefrontal cortex the genome-wide distribution of histone H3 trimethylated at lysine 4 (H3K4me3), an epigenetic mark sharply regulated at TSS, and identified 471 sequences with human-specific enrichment or depletion. Among these were 33 loci selectively methylated in neuronal but not non-neuronal chromatin from children and adults, including TSS at DPP10 (2q14.1), CNTN4 and CHL1 (3p26.3), and other neuropsychiatric susceptibility genes. Regulatory sequences at DPP10 and additional loci carried a strong footprint of hominid adaptation, including elevated nucleotide substitution rates and regulatory motifs absent in other primates (including archaic hominins), with evidence for selective pressures during more recent evolution and adaptive fixations in modern populations. Chromosome conformation capture at two neurodevelopmental disease loci, 2q14.1 and 16p11.2, revealed higher order chromatin structures resulting in physical contact of multiple human-specific H3K4me3 peaks spaced 0.5-1 Mb apart, in conjunction with a novel cis-bound antisense RNA linked to Polycomb repressor proteins and downregulated DPP10 expression. Therefore, coordinated epigenetic regulation via newly derived TSS chromatin could play an important role in the emergence of human-specific gene expression networks in brain that contribute to cognitive functions and neurological disease susceptibility in modern day humans

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum