2,959 research outputs found
Strain-induced topological phase transition in phosphorene and phosphorene nanoribbons
Using the tight-binding (TB) approximation with inclusion of the spin-orbit
interaction, we predict a topological phase transition in the electronic band
structure of phosphorene in the presence of axial strains. We derive a
low-energy TB Hamiltonian that includes the spin-orbit interaction for bulk
phosphorene. Applying a compressive biaxial in-plane strain and perpendicular
tensile strain in ranges where the structure is still stable leads to a
topological phase transition. We also examine the influence of strain on zigzag
phosphorene nanoribbons (zPNRs) and the formation of the corresponding
protected edge states when the system is in the topological phase. For zPNRs up
to a width of 100 nm the energy gap is at least three orders of magnitude
larger than the thermal energy at room temperature.Comment: 10 pages, 6 figure
Mapping of noise pollution by different interpolation methods in recovery section of Ghandi telecommunication Cables Company
Background: Noise pollution and workers\u27 noise exposure are common in industrial factories in Iran. In order to reduce this noise pollution, evaluation and investigation of noise emission are both necessary. In this study, different noise mapping methodsare used for determining the distribution of noise.
Materials and Methods: In the present study, for preparing a noise map in a hall of an industrial factory, sampling was carried out in 6×6 m grid. After data normalization the variogram was developed. For interpolation of mentioned parameter, kriging and Inverse Distance Weighting methods were used. The best model for interpolation was selected by cross validation and error evaluation methods, such as Route Mean Square Error(RMSE).
Results: The results showed that kriging method is better than other methods for prediction of noise property. The noise map was prepared, using the best interpolation method in Geographical Information System environment.
Conclusion: Workers in this industrial hall were exposed to noise which is mainly induced by noisy machines. Noise maps which were produced in this study showed the distribution of noise and, also revealed that workers suffer from serious noise pollution
Health inequalities and development plans in Iran: An analysis of the past three decades (1984–2010)
Introduction: Reducing inequalities in health care is one of the main challenges in all countries. In Iran as in other oil-exporting upper middle income countries, we expected to witness fewer inequalities especially in the health sector with the increase in governmental revenues.
Methods: This study presents an inequalities assessment of health care expenditures in Iran. We used data from the Household Income and Expenditure Survey (HIES) in Iran from 1984–2010. The analysis included 308,735 urban and 342,532 rural households.
Results: The results suggest heightened inequality in health care expenditures in Iran over the past three decades, including an increase in the gap between urban and rural areas. Furthermore, inflation has affected the poor more than the rich. The Kakwani progressivity index in all years is positive, averaging 0.436 in rural and 0.470 in urban areas during the time period of analysis. Compared to inequality in income distribution over the last 30 years, health expenditures continuously show more inequality and progressivity over the same period of time.
Conclusions: According to the result of our study, during this period Iran introduced four National Development Plans (NDPs); however, the NDPs failed to provide sustainable strategies for reducing inequalities in health care expenditures. Policies that protect vulnerable groups should be prioritized
Adenocarcinoma of small bowel
Small bowel cancer is one of the rarest cancers in the gastrointestinal tract. The diagnosis is usually late and most patients presented with the advanced stage. Because of this rarity, there is limited data when making decisions for treatment and biological behavior. Most forms of the cancer occur in the duodenum with surgery being the treatment of choice if the cancer is operable. Chemotherapy has an accepted role in duodenal cancer, with the best form being regimen, which yields the best result in combination with capecitabin and oxaliplatin. Our case patient was present with liver metastasis and a huge mass in her first duodenal region so we were required to use chemotherapy and radiotherapy. Like other duodenal cancers, the metastasis decreased her survival and she died about 13 months after diagnosis. © 2015 P. Fadavi and M. Zare
Buckling load analysis of cracked curved beams using differential quadrature element method
This paper investigates the buckling load of a cracked curved beam subjected to external excitations considering the effects of shear deformations and the geometric nonlinearity due to large deformations. The governing nonlinear equations of motion are derived. The solution consists of just static part, leading to nonlinear differential equations. The differential quadrature element method has been used to solve the problem. First, it is applied to the equilibrium equations, leading to a nonlinear algebraic system of equations that will be solved utilizing an arc length strategy. To verify the validity of the proposed method, the beam is modeled using the finite element method. The great agreement between the results shows the accuracy of the proposed method in predicting the loading of buckling of the beam
Overlapping Resonances Interference-induced Transparency: The Photoexcitation Spectrum of Pyrazine
The phenomenon of "overlapping resonances interference-induced transparency"
(ORIT) is introduced and studied in detail for the
photoexcitation of cold pyrazine (CHN). In ORIT a molecule becomes
transparent at specific wavelengths due to interferences between envelopes of
spectral lines displaying overlapping resonances. An example is the
internal conversion in pyrazine where destructive
interference between overlapping resonances causes the light
absorption to disappear at certain wavelengths. ORIT may be of practical
importance in multi-component mixtures where it would allow for the selective
excitation of some molecules in preference to others. Interference induced
cross section enhancement is also shown.Comment: 13 pages, 7 figure
Optimal mode matching in cavity optomagnonics
Inelastic scattering of photons is a promising technique to manipulate
magnons but it suffers from weak intrinsic coupling. We theoretically discuss
an idea to increase optomagnonic coupling in optical whispering gallery mode
cavities, by generalizing previous analysis to include the exchange
interaction. We predict that the optomagnonic coupling constant to surface
magnons in yttrium iron garnet (YIG) spheres with radius m
can be up to times larger than that to the macrospin Kittel mode. Whereas
this enhancement falls short of the requirements for magnon manipulation in
YIG, nanostructuring and/or materials with larger magneto-optical constants can
bridge this gap.Comment: Comments welcom
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