Lösbarkeit eines mathematischen Modells für Dichtungen mit magnetischen Flüssigkeiten

In dieser Arbeit betrachten wir ein mathematisches Modell zur Beschreibung der Strömungsverhältnisse in Dichtungen mit magnetischen Flüssigkeiten. Ausgehend vom physikalischen, dreidimensionalen Modell zeigen wir, daß aufgrund der geringen Spaltbreite eine zweidimensionale Betrachtungsweise zulässig ist. Die mathematische Lösbarkeit des vereinfachten Modells wird mit der Galerkin-Methode untersucht, wobei abweichend zu Standardtechniken schwache Mamimumprinzipien für gemischte Randwertaufgaben zum Einsatz kommen

Ion beam effect on Ge-Se chalcogenide glass films: Non-volatile memory array formation, structural changes and device performance

The conductive bridge non-volatile memory technology is an emerging way to replace traditional charge based memory devices for future neural networks and configurable logic applications. An array of the memory devices that fulfills logic operations must be developed for implementing such architectures. A scheme to fabricate these arrays, using ion bombardment through a mask, has been suggested and advanced by us. Performance of the memory devices is studied, based on the formation of vias and damage accumulation due to the interactions of Ar+ ions with GexSe1-x (x=0.2, 0.3 and 0.4) chalcogenide glasses as a function of the ion energy and dose dependence. Blanket films and devices were created to study the structural changes, surface roughness, and device performance. Raman Spectroscopy, Atomic Force Microscopy (AFM), Energy Dispersive X-Ray Spectroscopy (EDS) and electrical measurements expound the Ar+ ions behavior on thin films of GexSe1-x system. Raman studies show that there is a decrease in area ratio between edge-shared to corner-shared structural units, revealing occurrence of structural reorganization within the system as a result of ion/film interaction. AFM results demonstrate a tendency in surface roughness improvement with increased Ge concentration, after ion bombardment. EDS results reveal a compositional change in the vias, with a clear tendency of greater interaction between ions and the Ge atoms, as evidenced by greater compositional changes in the Ge rich films

ГЕНЕЗА И СВОЈСТВА НА РАНКЕРИТЕ РАСПРОСТРАНЕТИ ВО МЕСНОСТА КОНАР ПЕХЧЕВО

The study contains the results of the soil genesis condition, the genesis and properties of the ranker soil spread out of the Pehcevo in area Konar. This no carbonic soil,middle humus to weakly humus, mediumprovided to penurious of nitrogen, potassium, and weakly with phosphor, Sandy clay loam, sandy loam, loam to clay soils

Structural Transformation in Ge\u3csub\u3e\u3cem\u3ex\u3c/em\u3e\u3c/sub\u3eS\u3csub\u3e100−x\u3c/sub\u3e (10 ≤\u3cem\u3e x \u3c/em\u3e≤ 40) Network Glasses: Structural Varieties in Short-Range, Medium-Range, and Nanoscopic Scale

Precise x-ray diffraction measurements using high-energy x rays of synchrotron radiation and systematic Raman scattering measurements were carried out for GexS100−x (10 ⩽ x ⩽ 40) network glasses. The structural models of the network glasses were proposed based on the results. In the stoichiometric composition Ge33S67, GeS4 tetrahedral units are connected forming either corner-sharing or edge-sharing structures. In the S-rich glasses, S atoms are inserted between two neighboring GeS4 tetrahedra, resulting in a flexible floppy network. In a much more S-rich region, some S8 ring molecules are isolated from the network, and assemble to form a crystal in nanoscopic scale. In this respect, Ge10S90 samples are regarded as crystallized glasses. In the Ge-rich region, the GeS4 tetrahedra are connected with bridging Ge atoms. The connection makes a new rigid network. The bridging Ge-S bond is weaker than the intratetrahedron bond, and this leads to drastic changes in the optical properties

Numerical treatment of free surface problems in ferrohydrodynamics

The numerical treatment of free surface problems in ferrohydrodynamics is considered. Starting from the general model, special attention is paid to field-surface and flow-surface interactions. Since in some situations these feedback interactions can be partly or even fully neglected, simpler models can be derived. The application of such models to the numerical simulation of dissipative systems, rotary shaft seals, equilibrium shapes of ferrofluid drops, and pattern formulation in the normal-field instability of ferrofluid layers is given. Our numerical strategy is able to recover solitary surface patterns which were discovered recently in experiment

Influence of Cu Diffusion Conditions on the Switching of Cu-SiO\u3csub\u3e2\u3c/sub\u3e-Based Resistive Memory Devices

This paper presents a study of Cu diffusion at various temperatures in thin SiO2 films. Film composition and diffusion products were analyzed using Secondary Ion Mass Spectroscopy, Rutherford Backscattering Spectrometry, X-ray Diffraction and Raman Spectroscopy methods. We found a strong dependence of the diffused Cu concentration, which varied between 0.8 at.% and 10-3 at.%, on the annealing temperature. X-ray diffraction and Raman studies revealed that Cu does not react with the SiO2 network and remains in elemental form after diffusion. Programmable Metallization Cell (PMC) resistive memory cells were fabricated with these Cu-diffused SiO2 films as the active elements and device performance is presented and discussed in the context of the materials characteristics

Three-Dimensional Structure of N-Terminal Domain of DnaB Helicase and Helicase-Primase Interactions in Helicobacter pylori

Replication initiation is a crucial step in genome duplication and homohexameric DnaB helicase plays a central role in the replication initiation process by unwinding the duplex DNA and interacting with several other proteins during the process of replication. N-terminal domain of DnaB is critical for helicase activity and for DnaG primase interactions. We present here the crystal structure of the N-terminal domain (NTD) of H. pylori DnaB (HpDnaB) helicase at 2.2 Å resolution and compare the structural differences among helicases and correlate with the functional differences. The structural details of NTD suggest that the linker region between NTD and C-terminal helicase domain plays a vital role in accurate assembly of NTD dimers. The sequence analysis of the linker regions from several helicases reveals that they should form four helix bundles. We also report the characterization of H. pylori DnaG primase and study the helicase-primase interactions, where HpDnaG primase stimulates DNA unwinding activity of HpDnaB suggesting presence of helicase-primase cohort at the replication fork. The protein-protein interaction study of C-terminal domain of primase and different deletion constructs of helicase suggests that linker is essential for proper conformation of NTD to interact strongly with HpDnaG. The surface charge distribution on the primase binding surface of NTDs of various helicases suggests that DnaB-DnaG interaction and stability of the complex is most probably charge dependent. Structure of the linker and helicase-primase interactions indicate that HpDnaB differs greatly from E.coli DnaB despite both belong to gram negative bacteria

Atlas of prostate cancer heritability in European and African-American men pinpoints tissue-specific regulation

Although genome-wide association studies have identified over 100 risk loci that explain ~33% of familial risk for prostate cancer (PrCa), their functional effects on risk remain largely unknown. Here we use genotype data from 59,089 men of European and African American ancestries combined with cell-type-specific epigenetic data to build a genomic atlas of single-nucleotide polymorphism (SNP) heritability in PrCa. We find significant differences in heritability between variants in prostate-relevant epigenetic marks defined in normal versus tumour tissue as well as between tissue and cell lines. The majority of SNP heritability lies in regions marked by H3k27 acetylation in prostate adenoc7arcinoma cell line (LNCaP) or by DNaseI hypersensitive sites in cancer cell lines. We find a high degree of similarity between European and African American ancestries suggesting a similar genetic architecture from common variation underlying PrCa risk. Our findings showcase the power of integrating functional annotation with genetic data to understand the genetic basis of PrCa

Atlas of prostate cancer heritability in European and African-American men pinpoints tissue-specific regulation

Although genome-wide association studies have identified over 100 risk loci that explain similar to 33% of familial risk for prostate cancer (PrCa), their functional effects on risk remain largely unknown. Here we use genotype data from 59,089 men of European and African American ancestries combined with cell-type-specific epigenetic data to build a genomic atlas of single-nucleotide polymorphism (SNP) heritability in PrCa. We find significant differences in heritability between variants in prostate-relevant epigenetic marks defined in normal versus tumour tissue as well as between tissue and cell lines. The majority of SNP heritability lies in regions marked by H3k27 acetylation in prostate adenoc7arcinoma cell line (LNCaP) or by DNaseI hypersensitive sites in cancer cell lines. We find a high degree of similarity between European and African American ancestries suggesting a similar genetic architecture from common variation underlying PrCa risk. Our findings showcase the power of integrating functional annotation with genetic data to understand the genetic basis of PrCa