Компьютерное моделирование процессов роста тонких пленок при термическом вакуумном напылении

The various thin film growth mechanisms during thermal vacuum evaporation at atomic level are considered under different condition. Which factors and how influence on the quality of obtained thin films was demonstrated. The thin film’s growth process in intermediately (Stranski-Krastanov) mode was simulated based on Monte Carlo method for determination of active particles’ number, and quasi-Newtonian lattice method for determination of optimal direction of particles’ motion. On this model in any given conditions the fractal growth process was analyzed. The phenomenon (opportunity) of the control and management of the growth process of thin films was considered.Рассмотрены различные механизмы процесса роста тонких пленок на атомном уровне с учетом различных факторов при термическом вакуумном напылении. Продемонстрировано влияние этих факторов на качество получаемых пленок. При промежуточном механизме процесса роста тонких пленок для определения номера частицы применен метод Монте-Карло, для определения направления движения выбранной частицы - квазиньютоновский решетчатый метод. Проанализирован процесс фрактального роста с учетом всех факторов. Рассмотрены возможности управления процессом роста тонких пленок

Field-Induced Transition in the S=1 Antiferromagnetic Chain with Single-Ion Anisotropy in a Transverse Magnetic Field

The field-induced transition in one-dimensional S=1 Heisenberg antiferromagnet with single-ion anisotropy in the presence of a transverse magnetic field is obtained on the basis of the Schwinger boson mean-field theory. The behaviors of the specific heat and susceptibility as functions of temperature as well as the applied transverse field are explored, which are found to be different from the results obtained under a longitudinal field. The anomalies of the specific heat at low temperatures, which might be an indicative of a field-induced transition from a Luttinger liquid phase to an ordered phase, are explicitly uncovered under the transverse field. A schematic phase diagram is proposed. The theoretical results are compared with experimental observations.Comment: Revtex, 7 figure

ROCSAT-1 telecommunication experiments

This paper addresses a telecommunication payload project approved by the R.O.C. NSPO's ROCSAT-1 space program. This project will enable several innovative experiments via the low-earth-orbit satellite ROCSAT-1, including multipath fading channel characterization, ionospheric scintillation measurement, real-time voice communications, and CDMA data communications. A unified L/S-band transponder payload is proposed for conducting these experiments in an efficient way. The results of these experiments would provide the evolving mobile communication communities with fruitful information

Case report – ancient schwannoma of the scrotum

BACKGROUND: Scrotal schwannoma is a rare neoplasm and poses a diagnostic challenge to urologists. This article describes a rare case of ancient scrotal schwannoma and reviews the current modality of investigation and treatment of this tumour. CASE REPORT: A 28 year old man presented with a 3-month history of an asymptomatic scrotal swelling. Ultrasonography and computer topography revealed an intra-scrotal and extra-testicular mass without local invasion. Surgical excision was undertaken and histology was an ancient schwannoma of the scrotum. CONCLUSION: Schwannoma is a benign encapsulating neoplasm with an overall low incidence, occurring mostly in the head and neck region and seldom in the scrotum. Histology shows two distinctive patterns, Antoni type A and B areas. Variations of schwannoma such as cellular, ancient, glandular and epithelioid are observed based on the appearances. Ancient schwannoma exhibits pleomorphism without mitosis as the result of cellular degeneration, which can lead to an erroneous diagnosis of malignancy. Imaging modalities are non-specific for schwannomas, but can define tumour size, site and extension. The mainstay treatment is complete excision, although local recurrence may occur in large and incompletely excised lesions. Malignant change is exceedingly rare

Nonlinearization and waves in bounded media: old wine in a new bottle

We consider problems such as a standing wave in a closed straight tube, a self-sustained oscillation, damped resonance, evolution of resonance and resonance between concentric spheres. These nonlinear problems, and other similar ones, have been solved by a variety of techniques when it is seen that linear theory fails. The unifying approach given here is to initially set up the appropriate linear difference equation, where the difference is the linear travel time. When the linear travel time is replaced by a corrected nonlinear travel time, the nonlinear difference equation yields the required solution

The Influence of Age and Sex on Genetic Associations with Adult Body Size and Shape : A Large-Scale Genome-Wide Interaction Study

Genome-wide association studies (GWAS) have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHRadjBMI), a measure of body shape. Body size and shape change as people grow older and these changes differ substantially between men and women. To systematically screen for age- and/or sex-specific effects of genetic variants on BMI and WHRadjBMI, we performed meta-analyses of 114 studies (up to 320,485 individuals of European descent) with genome-wide chip and/or Metabochip data by the Genetic Investigation of Anthropometric Traits (GIANT) Consortium. Each study tested the association of up to ~2.8M SNPs with BMI and WHRadjBMI in four strata (men ≤50y, men >50y, women ≤50y, women >50y) and summary statistics were combined in stratum-specific meta-analyses. We then screened for variants that showed age-specific effects (G x AGE), sex-specific effects (G x SEX) or age-specific effects that differed between men and women (G x AGE x SEX). For BMI, we identified 15 loci (11 previously established for main effects, four novel) that showed significant (FDR<5%) age-specific effects, of which 11 had larger effects in younger (<50y) than in older adults (≥50y). No sex-dependent effects were identified for BMI. For WHRadjBMI, we identified 44 loci (27 previously established for main effects, 17 novel) with sex-specific effects, of which 28 showed larger effects in women than in men, five showed larger effects in men than in women, and 11 showed opposite effects between sexes. No age-dependent effects were identified for WHRadjBMI. This is the first genome-wide interaction meta-analysis to report convincing evidence of age-dependent genetic effects on BMI. In addition, we confirm the sex-specificity of genetic effects on WHRadjBMI. These results may provide further insights into the biology that underlies weight change with age or the sexually dimorphism of body shape

PAMELA and FERMI-LAT limits on the neutralino-chargino mass degeneracy

Searches for Dark Matter (DM) particles with indirect detection techniques have reached important milestones with the precise measurements of the anti-proton and gamma-ray spectra, notably by the PAMELA and FERMI-LAT experiments. While the gamma-ray results have been used to test the thermal Dark Matter hypothesis and constrain the Dark Matter annihilation cross section into Standard Model (SM) particles, the anti-proton flux measured by the PAMELA experiment remains relatively unexploited. Here we show that the latter can be used to set a constraint on the neutralino-chargino mass difference. To illustrate our point we use a Supersymmetric model in which the gauginos are light, the sfermions are heavy and the Lightest Supersymmetric Particle (LSP) is the neutralino. In this framework the W^+ W^- production is expected to be significant, thus leading to large anti-proton and gamma-ray fluxes. After determining a generic limit on the Dark Matter pair annihilation cross section into W^+ W^- from the anti-proton data only, we show that one can constrain scenarios in which the neutralino-chargino mass difference is as large as ~ 20 GeV for a mixed neutralino (and intermediate choices of the anti-proton propagation scheme). This result is consistent with the limit obtained by using the FERMI-LAT data. As a result, we can safely rule out the pure wino neutralino hypothesis if it is lighter than 450 GeV and constitutes all the Dark Matter.Comment: 22page

Моделирование и оптимизация функции качества технологических процессов формирования функциональных покрытий и пленок

The modeling of processes of formation of thin films in magnetron sputtering systems in the substrate potential field at different ratios of relations between the sprayed material and the substrate for various types of structures of the substrate is considered. Growth models of thin films point emitters integration method with the use of Monte-Carlo algorithms with accounting of the annealing are used. The comparison of results of computer simulation and experiment is executed; the inverse problem to optimization process using the quality function that takes into account the uniformity of the synthesized thin films, the flow of materials and the geometry of the spray is solved.Рассмотрено моделирование процессов формирования тонких пленок в установках магнетронного распыления. Моделирование основано на вероятностном подходе и интеграции точечных испарителей. При моделировании учитывались относительное распределение толщины тонких пленок и эффективность массопереноса частиц. Выполнено сравнение результатов компьютерного моделирования и эксперимента; решена обратная задача оптимизации процесса с использованием введенной функции качества, учитывающей равномерность синтезируемых тонких пленок, расход материалов и геометрию области распыления

Complementarity of Galactic radio and collider data in constraining WIMP dark matter models

In this work we confront dark matter models to constraints that may be derived from radio synchrotron radiation from the Galaxy, taking into account the astrophysical uncertainties and we compare these to bounds set by accelerator and complementary indirect dark matter searches. Specifically we apply our analysis to three popular particle physics models. First, a generic effective operator approach, in which case we set bounds on the corresponding mass scale, and then, two specific UV completions, the Z' and Higgs portals. We show that for many candidates, the radio synchrotron limits are competitive with the other searches, and could even give the strongest constraints (as of today) with some reasonable assumptions regarding the astrophysical uncertainties.Comment: 22 pages, 12 figure

Human Neural Stem Cells Over-Expressing VEGF Provide Neuroprotection, Angiogenesis and Functional Recovery in Mouse Stroke Model

BACKGROUND: Intracerebral hemorrhage (ICH) is a lethal stroke type. As mortality approaches 50%, and current medical therapy against ICH shows only limited effectiveness, an alternative approach is required, such as stem cell-based cell therapy. Previously we have shown that intravenously transplanted human neural stem cells (NSCs) selectively migrate to the brain and induce behavioral recovery in rat ICH model, and that combined administration of NSCs and vascular endothelial growth factor (VEGF) results in improved structural and functional outcome from cerebral ischemia. METHODS AND FINDINGS: We postulated that human NSCs overexpressing VEGF transplanted into cerebral cortex overlying ICH lesion could provide improved survival of grafted NSCs, increased angiogenesis and behavioral recovery in mouse ICH model. ICH was induced in adult mice by unilateral injection of bacterial collagenase into striatum. HB1.F3.VEGF human NSC line produced an amount of VEGF four times higher than parental F3 cell line in vitro, and induced behavioral improvement and 2–3 fold increase in cell survival at two weeks and eight weeks post-transplantation. CONCLUSIONS: Brain transplantation of F3 human NSCs over-expressing VEGF near ICH lesion sites provided differentiation and survival of grafted human NSCs and renewed angiogenesis of host brain and functional recovery of ICH animals. These results suggest a possible application of the human neural stem cell line, which is genetically modified to over-express VEGF, as a therapeutic agent for ICH-stroke