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排序方式: 共有195条查询结果,搜索用时 15 毫秒
71.
Soudeh Ghafouri-Fard Tahereh Azimi Bashdar Mahmud Hussen Mohammad Taheri Reza Jalili Khoshnoud 《International journal of molecular sciences》2021,22(23)
Myasthenia gravis (MG) is an autoimmune condition related to autoantibodies against certain proteins in the postsynaptic membranes in the neuromuscular junction. This disorder has a multifactorial inheritance. The connection between environmental and genetic factors can be established by epigenetic factors, such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). XLOC_003810, SNHG16, IFNG-AS1, and MALAT-1 are among the lncRNAs with a possible role in the pathoetiology of MG. Moreover, miR-150-5p, miR-155, miR-146a-5p, miR-20b, miR-21-5p, miR-126, let-7a-5p, and let-7f-5p are among miRNAs whose roles in the pathogenesis of MG has been assessed. In the current review, we summarize the impact of miRNAs and lncRNAs in the development or progression of MG. 相似文献
72.
In this paper, a 1-Gb/s analog Viterbi detector based on a 4-PAM duobinary scheme is discussed with experimental results for a 0.25-μm CMOS implementation. This chip is the first analog integrated implementation of a reduced state sequence detector. Pipelining and parallel processing have been incorporated in this design for high-speed operation. Due to test equipment limitations, experimental results are given for 200-Mb/s operation while simulation results indicate a speed of 1 Gb/s. Power dissipation is 55 mW from a 2.5-V supply. The active area occupies 0.78 mm2. Although a duobinary scheme has been the focus of this work for its application in optical links, this design can be readily modified or extended to other partial-response signaling schemes such as dicode and PR4 相似文献
73.
Somaye Karimkhani Zand Saeid Baghshahi Masoud Rajabi 《Journal of Materials Science: Materials in Electronics》2014,25(10):4412-4417
Luminescent nano-pigments based on strontium aluminates doped with various amounts of europium rare earth ion (Sr4Al14O25:Eu2+) were synthesized by solution combustion method which involves the exothermic reaction of an oxidizer and an organic fuel. It is a suitable method for producing chemically homogenous and pure powders with very fine particle size. Phases studies by X-ray diffractometer indicated formation of pure phase Sr4Al14O25 with crystallite sizes about 52.46 nm and peak shift of about 2θ = 0.26° due to Eu2+ doping. scanning electron microscope micrographs also revealed that the particles have irregular morphology and wide particle size distribution. The emission spectrum showed main emission peak at about 480 nm. Energy transfer mechanism between the two emission centers and the effect of Eu2+ ion concentration on emission spectrum was studied and it was deduced that the maximum emission intensity occurred at 4 at% of Eu2+. Absorption spectrum of the samples were lower than 0.5 %, especially in emission region of the doped pigments. 相似文献
74.
Xin Luo Yong Zhang Carl Zandén Murali Murugesan Yu Cao Lilei Ye Johan Liu 《Journal of Materials Science: Materials in Electronics》2014,25(5):2333-2338
With increased power density and continued miniaturization, effective thermal dissipation is of significant importance for operational lifetime and reliability of electronic system. Advanced thermal interface materials (TIMs) with excellent thermal performance need to be designed and developed. Here we report novel TIMs consisted of boron nitride (BN) nanofibers and pure indium (In) solder for heat dissipation applications. The BN nanofibers are fabricated by electrospinning process and nitridation treatment. After surface metallization by sputtering, the porous BN film is infiltrated with liquid indium by squeeze casting to form the final solid composites. The new composites show the in-plane and through-plane thermal conductivity respectively of 60 and 20 W/m K. The direction dependence thermal properties of the TIM are due to the anisotropic thermal performance of BN nanofibers in the composite. A low thermal contact resistance of 0.2 K mm2/W is also achieved at the interface between this new composite and copper substrate. These competent thermal properties demonstrate the great potential of the BN–In TIMs in thermal management for electronic system. 相似文献
75.
Mohadese Hossien-poor-Zaryabi Mahmoud Chamsaz Tahereh Heidari Mohammad Hossein Arbab Zavar Mohammad Behbahani Mani Salarian 《Food Analytical Methods》2014,7(2):352-359
In the present study, dispersive liquid–liquid micro-extraction has been applied for trace extraction and determination of mercury (Hg) ions in environmental samples. The mean centering of ratio spectra method was used to optimize the experimental parameters affecting the extraction of Hg. The factors influencing the extraction procedure such as type and volume of extracting and disperser solvent, concentration of chelating reagent, pH, salt effect, and centrifuge time were investigated and optimized. Under the optimized conditions, the limit of detection of the method was 0.15 μg l?1 and enrichment factor was 39. The calibration curve was linear in the range of 0.5–100 μg l?1 with a correlation of determination (R 2) of 0.998. The relative standard deviation for determination of 40 μg l?1 of Hg(II) was 2.6 % (n?=?5). The proposed method was applied for the determination of Hg in pine leaf, sea and river fish, sand, and water samples as indicators of environmental pollution and cigarette with satisfactory analytical results. In comparison with other methods, the proposed method is very simple, easy, rapid, and sensitive for determination of Hg at trace levels in complex matrices. 相似文献
76.
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78.
S. M. H. Seyedkashi H. Moslemi Naeini G. H. Liaghat M. Mosavi Mashadi M. Mirzaali K. Shojaee Y. H. Moon 《Journal of Mechanical Science and Technology》2012,26(6):1817-1822
The precise control of internal pressure and axial force loading paths significantly affects the final product quality. In this study, the effect of tube dimensions on the pressure and force loading paths in tube hydroforming process is investigated by using simulated annealing optimization method linked to a commercial finite element code. The optimized loading paths, obtained for different tube geometries with a constant expansion ratio, are then compared. The effects of initial diameter and wall thickness on shape conformation, optimal internal pressure and axial force (or feed) are discussed on the basis of optimal loading paths. Several guidelines in prediction and determination of tube hydroforming parameters are obtained by optimization analysis. 相似文献
79.
Tahereh KOROUZHDEH Hamid ESKANDARI-NADDAF Ramin KAZEMI 《Frontiers of Structural and Civil Engineering》2022,16(2):191-201
A new insight into the interfacial transition zone (ITZ) in cement mortar specimens (CMSs) that is influenced by cement fineness is reported. The importance of cement fineness in ITZ characterizations such as morphology and thickness is elucidated by backscattered electron images and by consequences to the compressive (Fc) and flexural strength (Ff), and porosity at various water/cement ratios. The findings indicate that by increasing the cement fineness the calcium silicate hydrate formation in the ITZ is favored and that this can refine the pore structures and create a denser and more homogeneous microstructure. By increasing cement fineness by about 25% of, the ITZ thickness of CMSs was reduced by about 30% and Fc was increased by 7%–52% and Ff by 19%–40%. These findings illustrate that the influence of ITZ features on the mechanical strength of CMSs is mostly related to the cement fineness and ITZ microstructure. 相似文献
80.
Characterization of coupled-domain multi-layer microplates in pull-in phenomenon, vibrations and dynamics 总被引:1,自引:0,他引:1
This paper presents a model to analyze pull-in phenomenon, vibrational behavior and dynamics of multi-layer microplates using coupled finite element and finite difference methods (FDM). First-order shear deformation theory (FSDT) is used to model dynamical system using finite element method, while FDM is applied to solve nonlinear Reynolds equation of squeeze film damping. Using this model, pull-in analysis of single- and multi-layer microplates are studied. Vibrational behavior of single- and multi-layer microplates are analyzed to compute resonance frequencies and mode shapes of the system. Also, an algorithm is presented to study dynamics of microplates under the actuation of nonlinear electrostatic force and squeeze film damping. Results for simplified single-layer microplates are validated and in good agreement with the published literature. This investigation can be implemented in the design of multi-layer microplates. 相似文献