2,129 research outputs found

    Quantum Dynamics in a Time-dependent Hard-Wall Spherical Trap

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    Exact solution of the Schr\"{o}dinger equation is given for a particle inside a hard sphere whose wall is moving with a constant velocity. Numerical computations are presented for both contracting and expanding spheres. The propagator is constructed and compared with the propagator of a particle in an infinite square well with one wall in uniform motion.Comment: 6 pages, 4 figures, Accepted by Europhys. Let

    The study of nano technology utilization in upgrading the quality of construction industry with fire-engineering approach

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    Today, the first requirement for increasing quality and strength in construction industry is utilization of appropriate and high quality materials so that usage of these materials, in addition to reducing maintenance costs and also upgrading the structure's longevity, in engineering respect through change on weight reduction and increasing strength in used materials, can cause general strength of the structure against earthquakes and probable runs due to natural disasters. This requirement is very significant in passive defense scope and this task will be considered in used material in main structure of a building and also in used materials in its frontage and in terminology elaborate work. Given that one of the effects of fire on the building part and parcel of passive defense, so, this look from the perspective of fire engineering is also of particular significance. Wide studies have been performed in this ground and various factories are trying to increase their produced materials quality in today competitive world with utilization of various technologies. One of technologies considered today is Nano technology which in fact by changing the molecular structure of a material causes creating special properties in it and utilization of these properties can answer needs of producers and users for increasing quality, longevity, strength and weight reduction. In this study, it is tried to introduce materials produced by Nano technology which have special properties like resistance against fire, settlement and weight reduction and increasing resistance in tolerance of strike and injected loads to the structure in defensive point of view in civil engineering scope. Keywords: Nano technology; passive defense; building material

    Band-edge Bilayer Plasmonic Nanostructure for Surface Enhanced Raman Spectroscopy

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    Spectroscopic analysis of large biomolecules is critical in a number of applications, including medical diagnostics and label-free biosensing. Recently, it has been shown that Raman spectroscopy of proteins can be used to diagnose some diseases, including a few types of cancer. These experiments have however been performed using traditional Raman spectroscopy and the development of the Surface enhanced Raman spectroscopy (SERS) assays suitable for large biomolecules could lead to a substantial decrease in the amount of specimen necessary for these experiments. We present a new method to achieve high local field enhancement in surface enhanced Raman spectroscopy through the simultaneous adjustment of the lattice plasmons and localized surface plasmon polaritons, in a periodic bilayer nanoantenna array resulting in a high enhancement factor over the sensing area, with relatively high uniformity. The proposed plasmonic nanostructure is comprised of two interacting nanoantenna layers, providing a sharp band-edge lattice plasmon mode and a wide-band localized surface plasmon for the separate enhancement of the pump and emitted Raman signals. We demonstrate the application of the proposed nanostructure for the spectral analysis of large biomolecules by binding a protein (streptavidin) selectively on the hot-spots between the two stacked layers, using a low concentration solution (100 nM) and we successfully acquire its SERS spectrum

    DFDL: Discriminative Feature-oriented Dictionary Learning for Histopathological Image Classification

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    In histopathological image analysis, feature extraction for classification is a challenging task due to the diversity of histology features suitable for each problem as well as presence of rich geometrical structure. In this paper, we propose an automatic feature discovery framework for extracting discriminative class-specific features and present a low-complexity method for classification and disease grading in histopathology. Essentially, our Discriminative Feature-oriented Dictionary Learning (DFDL) method learns class-specific features which are suitable for representing samples from the same class while are poorly capable of representing samples from other classes. Experiments on three challenging real-world image databases: 1) histopathological images of intraductal breast lesions, 2) mammalian lung images provided by the Animal Diagnostics Lab (ADL) at Pennsylvania State University, and 3) brain tumor images from The Cancer Genome Atlas (TCGA) database, show the significance of DFDL model in a variety problems over state-of-the-art methodsComment: Accepted to IEEE International Symposium on Biomedical Imaging (ISBI), 201

    fracture and microstructural study of bovine bone under mixed mode i ii loading

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    Abstract Understanding the fracture behavior and associated crack growth mechanism in bone material is an important issue for biomechanics and biomaterial researches. Fracture of bone often takes place due to complex loading conditions which result in combined tensile-shear (i.e. mixed mode) fracture mechanism. Several parameters such as loading type, applied loading direction relative to the bone axis, loading rate, age and etc., may affect the mixed mode fracture resistance and damage mechanism in such materials. In this research, a number of mixed mode I/II fracture experiments are conducted on bovine femur bone using a sub-sized test configuration called "compact beam bend (CBB)" specimen to investigate the fracture toughness of bone under different mode mixities. The specimen is rectangular beam containing a mid-edge crack that is loaded by a conventional three-point bend fixture. The results showed the dependency of bone fracture toughness on the state of mode mixity. The fracture surfaces of broken CBB specimens under different loading conditions were studied via scanning electron microscopy (SEM) observations. Fracture surface of all investigated cases (i.e. pure mode I, pure mode II and mixed mode I/II) exhibited smooth patterns demonstrating brittle fracture of bovine femur. The higher density of vascular channels and micro-cracks initiated in the weakened area surrounded by secondary osteons were found to be the main cause of the decreased bone resistance against crack growth and brittle fracture

    Determination of Tetanus Antibody Levels in Trauma Patients Referred To Shahid Beheshti Hospital in Kashan, Iran, 2014

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    Background: There is a noticeable difference in serologic immune status against tetanus among different age and social groups in various countries due to different national vaccination policies and methods. Objectives: Considering that the immunization status of trauma patients against tetanus is not-known or uncertain and they may need to receive the vaccine and tetabulin, this study was conducted to determine the tetanus antibody levels in patients referred to the trauma emergency ward of Shahid Beheshti Hospital in Kashan City, Iran. Patients and Methods: This cross-sectional study was performed on 204 trauma patients referred to the trauma emergency ward of Shahid Beheshti hospital in Kashan City, Iran, in 2014. After obtaining a written informed consent from the patients, a questionnaire consisted of demographic information and tetanus vaccination record was completed by the patients. Afterwards, a 4 - 5 mL venous blood sample was taken from each patient and the tetanus antibody level (IgG) was measured using the enzyme-linked immunosorbent assay method. The tetanus antibody levels equal or more than 0.1 IU/mL were considered protective. Data were analyzed using chi-square test, independent t-test and one-way ANOVA with SPSS software version 16. Results: From a total of 204 patients, 35 cases (16.7%) were females and 169 (83.2%) were males with the mean age of 40.9 ± 3.7 years. There was no statistically significant difference in the tetanus antibody levels between both sexes (P = 0.09). Moreover, there was no significant difference in immunization status between the patients who had a history of tetanus vaccination and those who had not received the vaccine before (P = 0.67). The antibody levels were significantly reduced with the passage of time since the last vaccination (P < 0.001). Also, 87.3% of the patients had the high protective level of immunity to tetanus. Conclusions: The findings of the present study show a high level of tetanus antibody among trauma patients in this hospital; so, taking the tetanus vaccine history can be misleading. It is suggested that further studies be performed in different regions of our country and with larger sample sizes and detection of the immunization status of patients by measuring anti-tetanus antibody levels among trauma patients is recommended to make suitable policy for a national vaccine protocol in the future

    Investigation of the Effect of Modeling of Control Tunnel in Retaining Structure of J2 Station of Mashhad Metro Using Plaxis 2D

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    Nowadays using of underground concrete arch excavation method is very common for execution of retaining structures (soldier structure) of deep and semi deep metro stations all around the world. In this method executer can use retaining structure as a part of main structure of station in next construction steps with using of piles of retaining structure as a part of main structure\u27s wall. One of the first steps in building retaining structure of metro station is control tunnel (patrol tunnel) that usually is a prefabricated controlling tunnel in the middle of retaining structure. This tunnel is used for digging bores for concrete piles and arches of retaining structure and will be removed at the end of excavation process. Usually designers don\u27t consider this tunnel in modeling of whole retaining structures in numerical modeling in computer programs like PLAXIS. We have done 2 different modeling of retaining structure of J2 station in Mashhad metro (with and without control tunnel) for considering of the impact of modeling of control tunnel on stresses, deflections, axial forces, bending moments, etc of the model using PLAXIS 8.5 2D. Results and differences between these two kinds of modeling showed that neglecting the patrol tunnel in analyses can cause important reductions in forces and moments of piles and ribs of the retaining structure
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