http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
High-frequency Oscillations in Small Magnetic Elements Observed with Sunrise/SuFI
Jafarzadeh, S.,Solanki, S. K.,Stangalini, M.,Steiner, O.,Cameron, R. H.,Danilovic, S. American Astronomical Society 2017 The Astrophysical journal Supplement series Vol.229 No.1
<P>We characterize waves in small magnetic elements and investigate their propagation in the lower solar atmosphere from observations at high spatial and temporal resolution. We use the wavelet transform to analyze oscillations of both horizontal displacement and intensity in magnetic bright points found in the 300. nm and the Ca II H 396.8 nm passbands of the filter imager on board the SUNRISE balloon-borne solar observatory. Phase differences between the oscillations at the two atmospheric layers corresponding to the two passbands reveal upward propagating waves at high frequencies (up to 30 mHz). Weak signatures of standing as well as downward propagating waves are also obtained. Both compressible and incompressible (kink) waves are found in the small-scale magnetic features. The two types of waves have different, though overlapping, period distributions. Two independent estimates give a height difference of approximately 450 +/- 100 km between the two atmospheric layers sampled by the employed spectral bands. This value, together with the determined short travel times of the transverse and longitudinal waves provide us with phase speeds of 29 +/- 2 km s(-1) and 31 +/- 2 km s(-1), respectively. We speculate that these phase speeds may not reflect the true propagation speeds of the waves. Thus, effects such as the refraction of fast longitudinal waves may contribute to an overestimate of the phase speed.</P>
Kinematics of Magnetic Bright Features in the Solar Photosphere
Jafarzadeh, S.,Solanki, S. K.,Cameron, R. H.,Barthol, P.,Rodrí,guez, J. Blanco,Iniesta, J. C. del Toro,Gandorfer, A.,Gizon, L.,Hirzberger, J.,Knö,lker, M.,Pillet, V. Martí,nez,Su&aacut American Astronomical Society 2017 The Astrophysical journal Supplement series Vol.229 No.1
<P>Convective flows are known as the prime means of transporting magnetic fields on the solar surface. Thus, small magnetic structures are good tracers of turbulent flows. We study the migration and dispersal of magnetic bright features (MBFs) in intergranular areas observed at high spatial resolution with SUNRISE/IMaX. We describe the flux dispersal of individual MBFs as a diffusion process whose parameters are computed for various areas in the quiet-Sun and the vicinity of active regions from seeing-free data. We find that magnetic concentrations are best described as random walkers close to network areas (diffusion index, gamma = 1.0), travelers with constant speeds over a supergranule (gamma = 1.9-2.0), and decelerating movers in the vicinity of flux emergence and/or within active regions (gamma = 1.4-1.5). The three types of regions host MBFs with mean diffusion coefficients of 130 km(2) s(-1), 80-90 km(2) s(-1), and 25-70 km(2) s(-1), respectively. The MBFs in these three types of regions are found to display a distinct kinematic behavior at a confidence level in excess of 95%.</P>
Slender Ca ii H Fibrils Mapping Magnetic Fields in the Low Solar Chromosphere
Jafarzadeh, S.,Rutten, R. J.,Solanki, S. K.,Wiegelmann, T.,Riethmü,ller, T. L.,Noort, M. van,Szydlarski, M.,Rodrí,guez, J. Blanco,Barthol, P.,Iniesta, J. C. del Toro,Gandorfer, A.,Gizon, L. American Astronomical Society 2017 The Astrophysical journal, Supplement series Vol.229 No.1
<P>A dense forest of slender bright fibrils near a small solar active region is seen in high-quality narrowband Ca II H images from the SuFI instrument onboard the SUNRISE balloon-borne solar observatory. The orientation of these slender Ca II H fibrils (SCF) overlaps with the magnetic field configuration in the low solar chromosphere derived by magnetostatic extrapolation of the photospheric field observed with SUNRISE/IMaX and SDO/HMI. In addition, many observed SCFs are qualitatively aligned with small-scale loops computed from a novel inversion approach based on best-fit numerical MHD simulation. Such loops are organized in canopy-like arches over quiet areas that differ in height depending on the field strength near their roots.</P>
Transverse Oscillations in Slender Ca ii H Fibrils Observed with Sunrise/SuFI
Jafarzadeh, S.,Solanki, S. K.,Gafeira, R.,Noort, M. van,Barthol, P.,Rodrí,guez, J. Blanco,Iniesta, J. C. del Toro,Gandorfer, A.,Gizon, L.,Hirzberger, J.,Knö,lker, M.,Suá,rez, D. Orozco American Astronomical Society 2017 The Astrophysical journal, Supplement series Vol.229 No.1
<P>We present observations of transverse oscillations in slender Ca II H fibrils (SCFs) in the lower solar chromosphere. We use a 1 hr long time series of high- (spatial and temporal-) resolution. seeing-free observations in a 1.1 angstrom wide passband covering the line core of Ca II H 3969 angstrom from the second flight of the SUNRISE balloon-borne solar observatory. The entire field of view, spanning the polarity inversion line of an active region close to the solar disk center, is covered with bright, thin, and very dynamic fine structures. Our analysis reveals the prevalence of transverse waves in SCFs with median amplitudes and periods on the order of 2.4 +/- 0.8 km s(-1) and 83 +/- 29 s, respectively (with standard deviations given as uncertainties). We find that the transverse waves often propagate along (parts of) the SCFs with median phase speeds of 9 +/- 14 km s(-1). While the propagation is only in one direction along the axis in some of the SCFs, propagating waves in both directions, as well as standing waves are also observed. The transverse oscillations are likely Alfvenic and are thought to be representative of magnetohydrodynamic kink waves. The wave propagation suggests that the rapid. high-frequency transverse waves,. often produced in the lower photosphere, can penetrate into the chromosphere. with an estimated energy flux of approximate to 15 kW m(-2). Characteristics of these waves differ from those reported for other fibrillar structures, which, however, were observed mainly in the upper solar chromosphere.</P>
Reza Jafarzadeh Esfehani,Masood Zahmatkesh,Reza Goldozian,Javad Farkhonde,Ehsan Jaripour,Asghar Hatami,Hamid Reza Bidkhori,Seyyed Khosro Shamsian,Seyyed AliAkbar Shamsian,Faezeh Mojahedi 대한백신학회 2023 Clinical and Experimental Vaccine Research Vol.12 No.1
Purpose: Since late 2019, the novel coronavirus disease has been a global concern, and alongside preventive strategies, including social distancing and personal hygiene, vaccination is now the primary hope for controlling the pandemic. Sputnik V is an adenovirus vector vaccine used against coronavirus disease 2019 (COVID-19) among Iranian health care providers, and there is a lack of information regarding the Adverse Events Following Immunisation (AEFI) by Sputnik V among the Iranian population. The present study aimed to evaluate AEFI by Sputnik V vaccine among Iranian population. Materials and Methods: Every member of the Islamic Republic of Iran Medical Council received their first dose of the Sputnik V vaccine in Mashhad (Iran) and was referred to receive their second dose enrolled in the present study and asked to fill an English language checklist asking about development of any AEFI following immunization with the first dose of Sputnik V vaccine. Results: A total number of 1,347 with a mean±standard deviation age of 56.2±9.6 years filled the checklist. Most of the participants were male (838 [62.2%]). The present study demonstrated that immunization with the first dose of Sputnik V results in at least one AEFI in 32.8% of the Iranian medical council members. Most of the AEFI was related to musculoskeletal symptoms, including myalgia. By considering the age of 55 years as a cut-off point, individuals younger than 55 had a higher rate of AEFI (41.3% vs. 22.5%, p=0.0001). Male gender, use of analgesics, beta-blockers, and previous COVID-19 infection have a lower chance of developing AEFI (p<0.05). Conclusion: The present study demonstrated that most of the AEFI was related to musculoskeletal symptoms, including myalgia, and older individuals, male gender and those receiving analgesics and beta-blockers were less likely to develop AEFI following immunization with the first dose of Sputnik V.
Analysis of lateral extrusion of gear-like form parts
H. Jafarzadeh,G. Faraji,A. F. Dizaji 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.10
The analysis of lateral extrusion process was carried out. A three dimensional FE model was developed to analyze the effects of some important geometrical parameters such as initial billet dimensions, gap height and frictional condition on the required forging load, the material flow pattern and effective plastic strain distribution. The FE code of DEFORM-3D was employed. A series of experimental tests on commercial lead billets were carried out to verify the FE results. The simulation work has been performed by the rigid-plastic FE method. The results obtained using the numerical solutions have been compared with the experimental data for each case study in terms of required forming load and material flow pattern in different regions. Comparison between FE and experiment results showed good agreement. Both the simulation and experimental results highlight the major role of above mentioned parameters on the required forming load and material flow pattern. The results showed that the gap height has the greatest effect on the forming load and material flow. The results presented in this paper could be used as basic data in the design of the lateral extrusion process.
H. Jafarzadeh,A. Babaei 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.6
A novel severe plastic deformation (SPD) technique entitled accumulative radial-forward extrusion (ARFE) is introduced for producingultra-fine grained bulk materials. This method is based on radial-forward extrusion process because of inherent capabilities for imposingextremely high plastic strains on material. ARFE was applied to AA1050 and the ability of this process in significant grain refinementis determined even after single cycle. Transmission electron microscopy (TEM) examination showed ultra-fine grains (UFGs) withthe average grain size of 450 nm after one cycle of ARFE. Furthermore, micro-hardness distribution through the part’s section indicatesthe hardness increase to ~52 Hv from the initial value of ~28 Hv after one cycle of ARFE. In order to further investigate of the accumulatedstrains, ARFE process was also numerically modelled by finite element method.