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A New Soft Switching Step-Down/Up Converter with Inherent PFC Performance
Jabbari, Masoud,Farzanehfard, Hosein The Korean Institute of Power Electronics 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.6
In this paper a new buck-boost type DC-DC converter is presented. Its voltage gain is positive, all active elements operate under soft-switching condition independent of loading, magnetic isolation and self output short-circuit protection exist, and very fast dynamic operation is achievable by a simple bang-bang controller. This converter also exhibits appropriate PFC characteristics since its input current is inherently proportional to the source voltage. When the voltage source is off-line, it is sufficient to add an inductor after the rectifier, then near unity power factor is achievable. All essential guidelines to design the converter as a DC-DC and a PFC regulator are presented. Simulation and experimental results verify the developed theoretical analysis.
Isolated Topologies of Switched-Resonator Converters
Jabbari, Masoud,Farzanehfard, Hosein,Shahgholian, Ghazanfar The Korean Institute of Power Electronics 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.2
Switched-resonator converters are a new family of soft switching DC-DC converters where the energy is transferred via a resonator. This paper introduces some isolated topologies of this family. The achieved advantages include, load independent soft-switching, self short-circuit protection, and optimization capability due to topology variety. Compared to conventional series-resonant converters, outstanding advantages such as a smaller fewer number of switches and diodes, a smaller transformer, and lower current stresses are achieved. A general synthesis scheme, functional topologies, and essential relations are included. Experimental results from a laboratory prototype confirm the presented theoretical analysis.
Jabbari, Sepideh,Hedayati, Mehdi,Yaghmaei, Parichehreh,Parivar, Kazem Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.15
Background: Vaspin and Retinol binding protein-4 (RBP4) are new adipokines mainly produced by adipose tissue. Considering that medullary thyroid carcinoma (MTC) is a malignant neuroendocrine tumor, and to date the relationship between serum levels of vaspin and RBP4 with MTC has not been studied, in this matched case-control study we evaluated their possible significance to this tumor type. Materials and Methods: A total of 45 patients with MTC (21 males and 24 females) and 45 healthy persons as a control group (24 males and 21 females) were selected. The two groups were matched for age, sex and body mass index. Serum Vaspin and RBP4 levels were measured by enzyme-linked immunosorbent assay (ELISA) methods in both groups. Also, weight and height were measured and body mass index was calculated too. Results: In total, patients with MTC had significantly higher serum vaspin levels compared to the controls (0.52ng/ml vs. 0.45ng/ml, P=0.0241). However, no significant difference was found in serum RBP4 concentrations between the patients with MTC and the controls ($15.2{\pm}2.55{\mu}g/ml$ versus $15.1{\pm}3.34{\mu}g/ml$, p>0.05). Conclusions: The results of this study demonstrated that serum RBP4 levels in MTC patients are not significantly different from those found in healthy individuals and did not correlate with MTC. On the other hand, higher levels of serum vaspin are associated with an increased risk of MTC. Thus Vaspin may be a novel and promising biomarker for diagnosis or confirmation of MTC in conjunction other specific tumor markers.
Increasing the performance of energy harvesting in vibration mode shapes
Jabbari, Majid,Ghayour, Mostafa,Mirdamadi, Hamid Reza Techno-Press 2016 Advances in computational design Vol.1 No.2
This paper presents a method of design for the energy harvesting of a piezoelectric cantilever beam. Vibration modes have strain nodes where the strain distribution changes in the direction of the beam length. Covering the strain nodes of the vibration modes with continuous electrodes effects a cancellation of the voltages outputs. The use of segmented electrodes avoids cancellations of the voltage for multi-mode vibration. The resistive load affects the voltage and generated power. The optimum resistive load is considered for segmented and continuous electrodes, and then the power output is verified. One of the effective parameters on energy harvesting performance is the existence of concentrated mass. This topic is studied in this paper. Resonance and off-resonance cases are considered for the harvester. In this paper, both theoretical and experimental methods are used for satisfactory results.
An Analytical Approach for Fast Recovery of the LSI Properties in Magnetic Particle Imaging
Jabbari Asl, Hamed,Yoon, Jungwon Hindawi Publishing Corporation 2016 International journal of biomedical imaging Vol.2016 No.-
<P>Linearity and shift invariance (LSI) characteristics of magnetic particle imaging (MPI) are important properties for quantitative medical diagnosis applications. The MPI image equations have been theoretically shown to exhibit LSI; however, in practice, the necessary filtering action removes the first harmonic information, which destroys the LSI characteristics. This lost information can be constant in the <I>x</I>-space reconstruction method. Available recovery algorithms, which are based on signal matching of multiple partial field of views (pFOVs), require much processing time and<I> a priori</I> information at the start of imaging. In this paper, a fast analytical recovery algorithm is proposed to restore the LSI properties of the <I>x</I>-space MPI images, representable as an image of discrete concentrations of magnetic material. The method utilizes the one-dimensional (1D) <I>x</I>-space imaging kernel and properties of the image and lost image equations. The approach does not require overlapping of pFOVs, and its complexity depends only on a small-sized system of linear equations; therefore, it can reduce the processing time. Moreover, the algorithm only needs<I> a priori</I> information which can be obtained at one imaging process. Considering different particle distributions, several simulations are conducted, and results of 1D and 2D imaging demonstrate the effectiveness of the proposed approach.</P>
Jabbari, M.,Vaghari, A.R.,Bahtui, A.,Eslami, M.R. Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.5
Transient solution of asymmetric mechanical and thermal stresses for hollow cylinders made of functionally graded material is presented. Temperature distribution, as function of radial and circumferential directions and time, is analytically obtained, using the method of separation of variables and generalized Bessel function. A direct method is used to solve the Navier equations, using the Euler equation and complex Fourier series.
Resonant CLL Non-Inverting Buck-Boost Converter
Jabbari, Masoud,Sharifi, Saead,Shahgholian, Ghazanfar The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.1
This paper presents a resonant non-inverting buck-boost converter in which all switches operate under ZCS conditions. In a symmetric configuration, a CLL resonant tank along with an inverter arm and a rectifying diode are employed. The diode is turned off at ZCS and hence the problem of its reverse recovery is obviated also. As a result switching losses and EMI are reduced and switching frequency can be increased. The converter can work at DCM and CCM depend on the switching frequency and the load-current. Experimental results from a 200W/200KHz laboratory prototype verify operation of the proposed converter and the presented theoretical analysis.