36 research outputs found
Coulomb Gap: How a Metal Film Becomes an Insulator
Electron tunneling measurements of the density of states (DOS) in ultra-thin
Be films reveal that a correlation gap mediates their insulating behavior. In
films with sheet resistance the correlation singularity appears
as the usual perturbative zero bias anomaly (ZBA) in the DOS. As R is
increased further, however, the ZBA grows and begins to dominate the DOS
spectrum. This evolution continues until a non-perturbative
Efros-Shklovskii Coulomb gap spectrum finally emerges in the highest R films.
Transport measurements of films which display this gap are well described by a
universal variable range hopping law .Comment: 4 figure
Ретроспективний аналіз наукових публікацій фармацевтичного журналу за 1959 – 2022 рр. щодо проблеми репродуктивного здоров’я жінок (повідомлення 3: лікарські засоби для лікування гінекологічних захворювань, безпліддя, клімаксу)
Вступ. Планування сім’ї потребує невідкладного вирішення проблем, пов’язаних з погіршенням здоров’я жінок по причині інфекційно-запальних захворювань репродуктивної системи. З цією метою перспективними є розробка, пошук та створення вагінальних лікарських форм для лікування вищезазначених захворювань, які мають безпосередній вплив на збудників захворювання та високу інтенсивність проникнення діючих речовин до оточуючих тканин. Сучасна фармацевтична промисловість розробляє нові та удосконалює відомі лікарські засоби для профілактики та лікування різних гінекологічних захворювань.
Мета дослідження - ретроспективний аналіз репродуктивного здоров’я жінок та аналіз комплексу організаційних та практичних заходів, спрямованих на зміцнення їх здоров’я шляхом застосування лікарських засобів для лікування гінекологічних захворювань, безпліддя, клімаксу.
Матеріали та методи. Матеріалами дослідження були 11 архівних наукових публікацій Фармацевтичного журналу за 1959-2022 роки з використанням методів контент-аналізу, історико-документального, узагальнення та систематизації даних.
Результати. Нами здійснений аналіз досліджень і наукових публікацій вітчизняних авторів щодо системного підходу до лікування захворювань інфекційно-запального характеру, окремих аспектів з розробки безпечних лікарських засобів для лікування гінекологічних захворювань, безпліддя, клімаксу. Одержані результати показали, що запропоновані авторами оригінальні лікарські препарати комплексної дії дозволяють забезпечити індивідуальний підхід та впливати на всі патогенетичні ланки запального процесу жіночих статевих органів. Допоміжні репродуктивні технології сприяють вирішенню проблеми безпліддя, яка є актуальною не лише в нашій країні, а й за кордоном. Колективами авторів були розглянуті питання менопаузи у жінок, діагностики та корекції клімактеричного синдрому, а також аспекти фармакотерапії клімактеричних порушень з використанням гормональних лікарських засобів та препаратів рослинного походження.
Висновки. Таким чином, результати ретроспективного аналізу свідчать про доцільність подальших досліджень щодо використання лікарських засобів для лікування гінекологічних захворювань, безпліддя, клімаксу
Residual nuclide formation in 206,207,208,nat-Pb and 209-Bi induced by 0.04-2.6 GeV Protons as well as in 56-Fe induced by 0.3-2.6 GeV Protons
5972 independent and cumulative yields of radioactive residuals nuclei have
been measured in 55 thin 206,207,208,nat-Pb and 209-Bi targets irradiated by
0.04, 0.07, 0.10, 0.15, 0.25, 0.6, 0.8, 1.2, 1.4, 1.6, and 2.6 GeV protons.
Besides, 219 yields have been measured in 0.3, 0.5, 0.75, 1.0, 1.5, and 2.6 GeV
proton-irradiated 56-Fe target. The protons were extracted from the ITEP U-10
synchrotron. The measured data are compared with experimental results obtained
elsewhere and with theoretical calculations by LAHET, MCNPX, CEM03, LAQGSM03,
CASCADE, CASCADO, and LAHETO codes. The predictive power was found to be
different for each of the codes tested, but was satisfactory on the whole in
the case of spallation products. At the same time, none of the codes can
de-scribe well the product yields throughout the whole product mass range, and
all codes must be further improved.Comment: 4 pages, 4 figures, 2 tables, only pdf file, to be published in Proc.
Int. Conf. on Nucl. Data for Sci. and Technology (ND2007), Nice, France,
April 22-27, 20
High-energy threshold reaction rates on 0.8 GeV proton-irradiated thick Pb-target
This works presents results of activation-aided determination of threshold
reaction rates in 92 209Bi, natPb, 197Au, 181Ta, 169Tm, natIn, 93Nb, 64Zn,
65Cu, 63Cu, 59Co, 19F, and 12C samples and in 121 27Al samples. All the samples
were aligned with the proton beam axis inside and outside the demountable 92-cm
thick Pb target of 15-cm diameter assembled of 23 4-cm thick discs. The samples
were placed on 12 target disks to reproduce the long axis distribution of
protons and neutrons. In June 2006, the target was exposed for 18 hours to a
800-MeV proton beam extracted from the ITEP U-10 accelerator. The proton
fluence and the proton beam shape were determined using the 27Al(p,x)7Be
monitor reaction. The reaction rates were determined by the direct
gamma-spectrometry techniques. In total, 1196 gamma-spectra have been measured,
and about 1500 reaction rates determined. The measured reaction rates were
simulated by the MCNPX code using the following databases: ENDF/B6 for neutrons
below 20 MeV, MENDL2 for 20-100 MeV neutrons, and MENDL2P for proton cross
sections up to 200 MeV. An acceptable agreement of simulations with
experimental data has been found.Comment: 4 pages, 5 figures, 3 tables, only pdf file, to be published in Proc.
Int. Conf. on Nucl. Data for Sci. and Technology (ND2007), Nice, France,
April 22-27, 200
Tenfold Magnetoconductance in a Non-Magnetic Metal Film
We present magnetoconductance (MC) measurements of homogeneously disordered
Be films whose zero field sheet conductance (G) is described by the
Efros-Shklovskii hopping law . The low field
MC of the films is negative with G decreasing 200% below 1 T. In contrast the
MC above 1 T is strongly positive. At 8 T, G increases 1000% in perpendicular
field and 500% in parallel field. In the simpler parallel case, we observe {\em
field enhanced} variable range hopping characterized by an attenuation of
via the Zeeman interaction.Comment: 9 pages including 5 figure
Superconductivity on the localization threshold and magnetic-field-tuned superconductor-insulator transition in TiN films
Temperature- and magnetic-field dependent measurements of the resistance of
ultrathin superconducting TiN films are presented. The analysis of the
temperature dependence of the zero field resistance indicates an underlying
insulating behavior, when the contribution of Aslamasov-Larkin fluctuations is
taken into account. This demonstrates the possibility of coexistence of the
superconducting and insulating phases and of a direct transition from the one
to the other. The scaling behavior of magnetic field data is in accordance with
a superconductor-insulator transition (SIT) driven by quantum phase
fluctuations in two-dimensional superconductor. The temperature dependence of
the isomagnetic resistance data on the high-field side of the SIT has been
analyzed and the presence of an insulating phase was confirmed. A transition
from the insulating to a metallic phase is found at high magnetic fields, where
the zero-temperature asymptotic value of the resistance being equal to h/e^2.Comment: 5 pages, 4 eps figures, RevTeX4, Published versio
Electron-electron interaction at decreasing
The contribution of the electron-electron interaction to conductivity is
analyzed step by step in gated GaAs/InGaAs/GaAs heterostructures with different
starting disorder. We demonstrate that the diffusion theory works down to , where is the Fermi quasimomentum, is the mean free
paths. It is shown that the e-e interaction gives smaller contribution to the
conductivity than the interference independent of the starting disorder and its
role rapidly decreases with decrease.Comment: 5 pages, 6 figure
Ambipolar gate effect and low temperature magnetoresistance of ultrathin La0.8Ca0.2MnO3 Films
Ultrathin La0.8Ca0.2MnO3 films have been measured in a field-effect geometry.
The electric field due to the gate produces a large ambipolar decrease in
resistance at low temperatures. This is attributed to the development of a
pseudogap in the density of states and the couple of localized charge to
strain. The gate effect and mangetoresistance are interpreted in a consistent
framework. The implications for the low temperature behavior of a manganite
film in the two dimensional limit are discussed.Comment: 4 pages, 3 figure
Cross-sections for nuclide production in 56Fe target irradiated by 300, 500,750, 1000, 1500, and 2600 MeV protons compared with data on hydrogen target irradiation by 300, 500, 750, 1000, and 1500 MeV/nucleon 56Fe ions
Cross-sections for radioactive nuclide production in 56Fe(p,x) reactions at
300, 500, 750, 1000, 1500, and 2600 MeV were measured using the ITEP U-10
proton accelerator. In total, 221 independent and cumulative yields of products
of half-lives from 6.6 min to 312 days have been obtained via the
direct-spectrometry method. The measured data have been compared with the
experimental data obtained elsewhere by the direct and inverse kinematics
methods and with calculations by 15 codes, namely: MCNPX (INCL, CEM2k, BERTINI,
ISABEL), LAHET (BERTINI, ISABEL), CEM03 (.01, .G1, .S1), LAQGSM03 (.01, .G1,
>.S1), CASCADE-2004, LAHETO, and BRIEFF. Most of our data are in a good
agreement with the inverse kinematics results and disprove the results of some
earlier activation measurements that were quite different from the inverse
kinematics measurements. The most significant calculation-to-experiment
differences are observed in the yields of the A<30 light nuclei, indicating
that further improvements in nuclear reaction models are needed, and pointing
out as well to a necessity of more complete measurements of such reactions.Comment: 53 pages, 9 figures, 6 tables, only pdf file, submitted to Phys. Rev.
Verification of high-energy transport codes on the basis of activation data
Nuclide production cross sections measured at ITEP for the targets of nat-Cr,
56-Fe, nat-Ni, 93-Nb, 181-Ta, nat-W, nat-Pb, 209-Bi irradiated by protons with
energies from 40 to 2600 MeV were used to estimate the predictive accuracy of
several popular high-energy transport codes. A general agreement of the ITEP
data with the data obtained by other groups, including the numerous GSI data
measured by the inverse kinematics method was found. Simulations of the
measured data were performed with the MCNPX (Bertini and ISABEL options),
CEM03.02, INCL4.2+ABLA, INCL4.5+ABLA07, PHITS, and CASCADE.07 codes. Deviation
factors between the calculated and experimental cross sections have been
estimated for each target and for the whole energy range covered by our
measurements. Two-dimensional diagrams of deviation factor values were produced
for estimating the predictive power of every code for intermediate, not
measured masses of nuclei-targets and bombarding energies of protons. Further
improvements of all tested here codes are recommended. In addition, new
measurements at ITEP of nuclide yields from a 208-Pb target irradiated by 500
MeV protons are presented. A good agreement between these new data and the GSI
measurements obtained by the inverse kinematics method was foundComment: 31 pages, 18 figures, 6 tables, only pdf, LANL Report LA-UR-11-02704,
Los Alamos (2011), submitted to Phys. Rev.