1,776 research outputs found
Технічні переваги системи седиментаційного відновлення стічних вод міста
The work designs a system of production components of urban infrastructure to create an energy efficient city. Hydraulic, hydrological, heat exchange processes of interaction of water structure and elements of treatment structures for centrifugal deposition of suspended matter have been investigated. Depending on the degree of contamination, devices for resource recovery are calculated. The duration of recovery operations was investigated. The technological cycle of re-water recovery and the number of cycles of cavitation generator for controlled conditioning of conditionally clean and dirty waters have been determined. Reverse osmosis devices for the recovery of conditionally pure water have been investigated. Categorized potential effluents of industrial waters as appropriate for restoration. Samples of experimental sediments for the needs of the construction industry at operating and supercritical modes of operation of the technological stream were obtained. A mathematical model of the productivity of irrigation of agro-centers in drought conditions with drip irrigation by repeated water has been developed.Робота проектує систему виробничих компонентів міської інфраструктури для створення енергоефективного міста. Досліджено гідравлічні, гідрологічні, теплообмінні процесі взаємодії водної структури та елементів очисних конструкцій для відцентрового осадження завислих речовин. Розраховано залежно від ступеня забруднення апарати для відновлення ресурсу. Досліджено тривалість операцій відновлення. Визначено технологічний цикл відновлення повторної води та кількість циклів кавітаційного генератора для керованого кондиціювання умовно чистих та брудних вод. Досліджено апарати зворотного осмосу для відновлення умовно чистих вод. Категоризовані потенційні стоки промислових вод за доцільністю відновлення. Отримано зразки експериментальних осадів для потреб будівельного господарства при робочих та надкритичних режимах роботи технологічної цівки. Розроблена математична модель продуктивності зрошення агроцентрів в умовах засухи крапельним зрошенням повторною водою
Ordered droplet structures at the liquid crystal surface and elastic-capillary colloidal interactions
We demonstrate a variety of ordered patterns, including hexagonal structures
and chains, formed by colloidal particles (droplets) at the free surface of a
nematic liquid crystal (LC). The surface placement introduces a new type of
particle interaction as compared to particles entirely in the LC bulk. Namely,
director deformations caused by the particle lead to distortions of the
interface and thus to capillary attraction. The elastic-capillary coupling is
strong enough to remain relevant even at the micron scale when its
buoyancy-capillary counterpart becomes irrelevant.Comment: 10 pages, 3 figures, to be published in Physical Review Letter
Superconductivity in the Cuprates as a Consequence of Antiferromagnetism and a Large Hole Density of States
We briefly review a theory for the cuprates that has been recently proposed
based on the movement and interaction of holes in antiferromagnetic (AF)
backgrounds. A robust peak in the hole density of states (DOS) is crucial to
produce a large critical temperature once a source of hole attraction is
identified. The predictions of this scenario are compared with experiments. The
stability of the calculations after modifying some of the original assumptions
is addressed. We find that if the dispersion is changed from an
antiferromagnetic band at half-filling to a tight binding
narrow band at , the main conclusions of the approach remain
basically the same i.e. superconductivity appears in the -channel and is enhanced by a large DOS. The main features
distinguishing these ideas from more standard theories based on
antiferromagnetic correlations are here discussed.Comment: RevTex, 7 pages, 5 figures are available on reques
Low energy states with different symmetries in the t-J model with two holes on a 32-site lattice
We study the low energy states of the t-J model with two holes on a 32-site
lattice with periodic boundary conditions. In contrary to common belief, we
find that the state with d_{x^2-y^2} symmetry is not always the ground state in
the realistic parameter range 0.2\le J/t\le 0.4. There exist low-lying
finite-momentum p-states whose energies are lower than the d_{x^2-y^2} state
when J/t is small enough. We compare various properties of these low energy
states at J/t=0.3 where they are almost degenerate, and find that those
properties associated with the holes (such as the hole-hole correlation and the
electron momentum distribution function) are very different between the
d_{x^2-y^2} and p states, while their spin properties are very similar.
Finally, we demonstrate that by adding ``realistic'' terms to the t-J model
Hamiltonian, we can easily destroy the d_{x^2-y^2} ground state. This casts
doubt on the robustness of the d_{x^2-y^2} state as the ground state in a
microscopic model for the high temperature superconductors
Polaron Effects on Superexchange Interaction: Isotope Shifts of , , and in Layered Copper Oxides
A compact expression has been obtained for the superexchange coupling of
magnetic ions via intermediate anions with regard to polaron effects at both
magnetic ions and intermediate anions. This expression is used to analyze the
main features of the behavior of isotope shifts for temperatures of three types
in layered cuprates: the Neel temperatures (), critical temperatures of
transitions to a superconducting state (), and characteristic temperatures
of the pseudogap in the normal state ().Comment: 4 pages, 1 figur
Changes in DNA methylation profile in liver tissue during progression of HCV-induced fibrosis to hepatocellular carcinoma
In this study we compared methylation levels of 27,578 CpG sites between paired samples of the tumor and surrounding liver tissues with various degrees of damage (fibrosis, cirrhosis) in HCV-induced hepatocellular carcinoma (HCC) patients, as well as between tumor and normal tissue in non-viral HCC patients, using GSE73003 and GSE37988 data from GEODataSets (https://www.ncbi.nlm.nih.gov/). A significantly lower number of differentially methylated sites (DMS) were found between HCC of non-viral etiology and normal liver tissue, as well as between HCC and fibrosis (32 and 40), than between HCC and cirrhosis (2450 and 2304, respectively, according to GSE73003 and GSE37988 datasets). As the pathological changes in the tissue surrounding the tumor progress, the ratio of hyper-/ hypomethylated DMSs in the tumor decreases. Thus, in tumor tissues compared with normal/fibrosis/cirrhosis of the liver, 75/62.5/47.7 % (GSE73003) and 16 % (GSE37988) of CpG sites are hypermethylated, respectively. Persistent hypermethylation of the ZNF154 and ZNF540 genes, as well as CCL20 hypomethylation, were registered in tumor tissue in relation to both liver fibrosis and liver cirrhosis. Protein products of the EDG4, CCL20, GPR109A, and GRM8 genes, whose CpG sites are characterized by changes in DNA methylation level in tumor tissue in the setting of cirrhosis and fibrosis, belong to “Signaling by G-protein-coupled receptors (GPCRs)” category. However, changes in the methylation level of the “driver” genes for oncopathology (АРС, CDKN2B, GSTP1, ELF4, TERT, WT1) are registered in tumor tissue in the setting of liver cirrhosis but not fibrosis. Among the genes hypermethylated in tumor tissue in the setting of liver cirrhosis, the most represented biological pathways are developmental processes, cell-cell signaling, transcription regulation, Wnt-protein binding. Genes hypomethylated in liver tumor tissue in the setting of liver cirrhosis are related to olfactory signal transduction, neuroactive ligand-receptor interaction, keratinization, immune response, inhibition of serine proteases, and zinc metabolism. The genes hypermethylated in the tumor are located at the 7p15.2 locus in the HOXA cluster region, and the hypomethylated CpG sites occupy extended regions of the genome in the gene clusters of olfactory receptors (11p15.4), keratin and keratin-associated proteins (12q13.13, 17q21.2, and 21q22.11), epidermal differentiation complex (1q21.3), and immune system function loci 9p21.3 (IFNA, IFNB1, IFNW1 cluster) and 19q13.41–19q13.42 (KLK, SIGLEC, LILR, KIR clusters). Among the genes of fibrogenesis or DNA repair, cg14143055 (ADAMDEC1) is located in the binding region of the HOX gene family transcription factors (TFs), while cg05921699 (CD79A), cg06196379 (TREM1) and cg10990993 (MLH1) are located in the binding region of the ZNF protein family transcription factor (TF). Thus, the DNA methylation profile in the liver in HCV-induced HCC is unique and differs depending on the degree of surrounding tissue lesion – liver fibrosis or liver cirrhosis
Single Spin Superconductivity: Formulation and Ginzburg-Landau Theory
We describe a novel superconducting phase that arises due to a pairing
instability of the half-metallic antiferromagnetic (HM AFM) normal state. This
single spin superconducting (SSS) phase contains broken time reversal symmetry
in addition to broken gauge symmetry, the former due to the underlying magnetic
order in the normal state. A classification of normal state symmetries leads to
the conclusion that the HM AFM normal phase whose point group contains the
inversion operator contains the least symmetry possible which still allows for
a zero momentum pairing instability. The Ginzburg-Landau free energy for the
superconducting order parameter is constructed consistent with the symmetry of
the normal phase, electromagnetic gauge invariance and the crystallographic
point group symmetry including inversion. For cubic, hexagonal and tetragonal
point groups, the possible symmetries of the superconducting phase are
classified, and the free energy is used to construct a generalized phase
diagram. We identify the leading candidate out of the possible SSS phases for
each point group. The symmetry of the superconducting phase is used to
determine the cases where the gap function has generic zeros (point or line
nodes) on the Fermi surface. Such nodes always occur, hence thermodynamic
properties will have power-law behavior at low temperature.Comment: 39 pages, RevTeX, 4 PostScript figures included, submitted to Phys.
Rev.
New palynological data for Toarcian (Lower Jurassic) deep-marine sandstones of the Western Caucasus, southwestern Russia
Information on Jurassic palynomorphs from the Greater Caucasus is potentially of great importance, but its availability to the international research community is severely limited. New palynological data for Toarcian deposits of the Western Caucasus are recorded in the present paper. Particularly, dinoflagellate cysts are described for the first time from the Bagovskaja Formation; palynomorphs are found in sandstone levels within this unit. The most representative
assemblage includes pollen (with predominant bisaccate pollen), spores (Cyathidites being commonest), and dinoflagellate cysts amongst which the predominant taxon is Nannoceratopsis spiculata. The dinocyst assemblage implies a late Toarcian age for the upper part of the Bagovskaja Formation. On the basis of these new palynostratigraphical results, the range of the formation is extended; previously, only the lower part had been dated on ammonite evidence
Hole photoproduction in insulating copper oxide
Basing on t-J model we calculate the k-dependence of a single hole
photoproduction probability for CuO2 plane at zero doping. We also discuss the
radiation of spin-waves which can substantially deform the shape of
photoemission spectra.Comment: latex 8 pages, 3 figure
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