811 research outputs found
Preparation and properties of hibryd organic-inorganic composites baced on poly-Ti02
Optically transparent hybrid organic-inorganic copolymers based on the poly-
TiO2, vinyl monomers and lactide or glycolide have been prepared. Optical and physi-
cal-mechanical properties of composites are depended with the ratio of components have
shown. Hybrid copolymers possess photochromic properties. By the UV light excitation
reversible darkening of the samples due to the transition Ti
4+
ļ Ti
3+
had observed. The
speed of transition depends on the copolymer composition.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2059
Global Models, The Biospheric Approach (Theory of the Noosphere)
The problem of the coevolution of mankind and the biosphere, i.e., the relationship between the process of the evolution of the biosphere and the evolution of human activity which provides a homeostasis for human civilization, has become one of the principal problems of human ecology.
The first step in an extensive program of interdisciplinary research is the creation of a system of mathematical models which would serve as a framework for planning international research programs.
The research described herein has two stages. The first stage, a still primitive system of models was constructed and analyzed, using systems dynamics techniques. This system of models, outlined in the second section of the paper, has already helped the authors in their contacts with experts in biology, soil science, etc., and the creation of an information base has in essence, turned into a discussion of plans for future work. Studies connected with simulating the evolution of the biosphere were developed in three directions: simulation of processes of a biotic nature, simulation of climate, and simulation of human activity.
Experimental results obtained using this system in the "if...then" mode, may be helpful for understanding, at least on a qualitative basis, possible impacts of human activity on the evolution of the biosphere assuming that the present day trends remain unchanged. This system of models is at present programmed at IIASA and is ready to be used for simulation experiments.
The second step in the research is based on an understanding of the fact that the systems dynamic approach is not sufficient for the elaboration and study of the system of models which describes human activity. Furthermore, it is necessary to analyze and coordinate models developed by experts in varied branches of science -- biologists, climatologists, economists, etc. Thus, it is necessary to elaborate new mathematical techniques that can be used in the investigation of global coevolution problems. Some principles for the development of these techniques were formulated at the Computing Center of the USSR Academy of Sciences and are presented herein. The three main principles are:
(1) Linear parametrization of comprehensive submodels;
(2) Models of human activity are split into two levels -- the decision-making level and the technological level -- and a description of the system of models at the technological level only;
(3) Analysis and coordination of the system of models by constructing a set of all reachable values of performance indices (The Generalized Reachable Sets Approach).
The linear parametrization procedure for a climate model which is essentially the Mintz-Arakawa global atmospheric circulation model as described by Gates et al. (1971) and modified to account for the climatic trends due to the influence of anthropogenic factors, is described in the third section of the paper.
The problems of modeling human activity and the main features of the Generalized Reachable Sets approach, as well as the general scheme of analysis of global biospheric models, are presented in the fourth section of the paper.
This work, which is now in the early stages, calls for a great deal of scientific effort over a long period of time. The authors anticipate that the importance of the research in this direction will be internationally recognized and supported
Nuclear emulsion with molybdenum filling for observation of decay
The usage of nuclear emulsion with molybdenum filling for observation of
decay are shown to be possible. Estimates for 1 kg of Mo
with zero background give the sensitivity for the decay of
Mo at the level of y for 1 year of measurement.Comment: 7 pages, 3 figure
Noise spectroscopy of a single spin with spin polarized STM
We show how the noise in a spin polarized STM tunneling current gives
valuable spectroscopic information on the temporal susceptibility of a single
magnetic atom residing on a non-magnetic surface.Comment: 6 pages, 1 figure. To appear in Physical Review
Experimental Evidence of Giant Electron - Gamma Bursts Generated by Extensive Atmospheric Showers in Thunderclouds
The existence of a new phenomena - giant electron-gamma bursts is
established. The bursts are generated in thunderclouds as a result of the
combined action of runaway breakdown and extensive atmosphere showers (RB-EAS).
The experiments were fulfilled at the Tien Shan Mountain Scientific Station
using EAS-Radio installation. This specially constructed installation consists
of a wide spread EAS trigger array and a high time resolution
radiointerferometer.Comment: 30 pages, 16 figure
Современные аспекты использования клеточных технологий в гинекологии
The article presents a review of publications devoted to the use of regenerative technologies in the treatment of gynecological pathologies. The authors describe possible ways to solve these problems by analyzing the experimental studies conducted in the world. Identified the main indications for tissue engineering: Ashermans syndrome, primary ovarian failure, infertility caused by chemotherapy, a niche in the uterus, endometrial pathology (endometriosis, endometrial problems, etc.), cervical pathology, female genital tract abnormalities, pelvic organ prolapse. The results of clinical trials of cell therapy aimed at treating infertility caused by Asherman syndrome and primary ovarian failure, female genital tract abnormalities, as well as such rare pathology as a niche of the uterus. At the preclinical stage, in addition to the above, considered cellular therapy of cervical pathologies, endometrial diseases and pelvic organ prolapse. Eximined cell cultures and the level of their influence on the regeneration of the female reproductive system structures, presented the biological scaffolds that stimulate the growth of stem cells, their effectiveness and shortcomings are covered.В предлагаемом систематическом обзоре представлен анализ данных клинических и доклинических исследований в области гинекологии, в которых применяли клеточные технологии. Определены основные показания для применения тканеинженерных конструкций: синдром Ашермана, первичная яичниковая недостаточность, бесплодие, несостоятельность рубца на матке, патологии эндометрия (эндометриоз, проблемы эндометрия и др.), патологии шейки матки, аномалии развития женской половой сферы, пролапс тазовых органов. На данный момент описаны результаты клинических испытаний клеточной терапии, направленной на лечение бесплодия при синдроме Ашермана и первичной яичниковой недостаточности, врожденных аномалиях женской половой сферы, а также при такой редкой патологии, как несостоятельность рубца на матке. На доклинической стадии помимо вышеперечисленных рассматривается клеточная терапия патологий шейки матки, заболеваний эндометрия и пролапса тазовых органов. Представлены клеточные культуры и уровень их воздействия на процессы регенерации структур половой системы женщины, рассмотрены биологические матрицы, стимулирующие рост стволовых клеток, их эффективность и недостатки. В настоящее время в России появилась нормативно-правовая база для внедрения в клиническую практику новых средств лечения с использованием живых клеток человека
The prototype of radioactive ion source
The design and experimental results of the RIB source prototype are presented. A source will have the container of ²³⁵U compounds heated up to 2200-2500°C. Vapors of uranium fission obtained when the ion source is irradiated by the high-energy neutron flux, are then ionized and extracted from the source. In the experiments with the prototype loaded by ¹²C the source working temperature 2700°C was reached, the carbon ion current 10 nA was obtained. The total operation time of more than 100 hours with no performance degradation was demonstrated
Enhancement of fusion rates due to quantum effects in the particles momentum distribution in nonideal media
This study concerns a situation when measurements of the nonresonant
cross-section of nuclear reactions appear highly dependent on the environment
in which the particles interact. An appealing example discussed in the paper is
the interaction of a deuteron beam with a target of deuterated metal Ta. In
these experiments, the reaction cross section for d(d,p)t was shown to be
orders of magnitude greater than what the conventional model predicts for the
low-energy particles. In this paper we take into account the influence of
quantum effects due to the Heisenberg uncertainty principle for particles in a
non-ideal medium elastically interacting with the medium particles. In order to
calculate the nuclear reaction rate in the non-ideal environment we apply both
the Monte Carlo technique and approximate analytical calculation of the Feynman
diagram using nonrelativistic kinetic Green's functions in the medium which
correspond to the generalized energy and momentum distribution functions of
interacting particles. We show a possibility to reduce the 12-fold integral
corresponding to this diagram to a fivefold integral. This can significantly
speed up the computation and control accuracy. Our calculations show that
quantum effects significantly influence reaction rates such as p +7Be, 3He
+4He, p +7Li, and 12C +12C. The new reaction rates may be much higher than the
classical ones for the interior of the Sun and supernova stars. The possibility
to observe the theoretical predictions under laboratory conditions is
discussed
Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS
We present the results of a search for new, heavy particles that decay at a
significant distance from their production point into a final state containing
charged hadrons in association with a high-momentum muon. The search is
conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV
and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS
detector operating at the Large Hadron Collider. Production of such particles
is expected in various scenarios of physics beyond the standard model. We
observe no signal and place limits on the production cross-section of
supersymmetric particles in an R-parity-violating scenario as a function of the
neutralino lifetime. Limits are presented for different squark and neutralino
masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final
version to appear in Physics Letters
- …