Modeling of a Cantilever-Based Near-Field Scanning Microwave Microscope

We present a detailed modeling and characterization of our scalable microwave nanoprobe, which is a micro-fabricated cantilever-based scanning microwave probe with separated excitation and sensing electrodes. Using finite-element analysis, the tip-sample interaction is modeled as small impedance changes between the tip electrode and the ground at our working frequencies near 1GHz. The equivalent lumped elements of the cantilever can be determined by transmission line simulation of the matching network, which routes the cantilever signals to 50 Ohm feed lines. In the microwave electronics, the background common-mode signal is cancelled before the amplifier stage so that high sensitivity (below 1 atto-Farad capacitance changes) is obtained. Experimental characterization of the microwave probes was performed on ion-implanted Si wafers and patterned semiconductor samples. Pure electrical or topographical signals can be realized using different reflection modes of the probe.Comment: 7 figure

Exact FLRW cosmological solutions via invariants of the symmetry groups

Until now, various methods have been demonstrated to solve the Friedmann-Lama\'{\i}tre-Robertson-Walker (FLRW) equations in the spatially flat $(k=0)$ cosmological model. In this study, in order to solve the field equations of the spatially flat FLRW cosmological model in the presence of $\Lambda$, a new method based on the invariants of the symmetry groups which we called ISG-method, is presented. This method is based on the extended Prelle-Singer (PS) method and it uses the Lie point symmetry, $\lambda$-symmetry and Darboux polynomials (DPs). We employ this method to extract systematically the two independent first integrals (or invariants) such as $I_1 (a,\dot{a})=c_1$ and $I_2 (t,a,\dot{a})=c_2$ associated to the group of the Lie point transformations keeping the Friedmann-Einstein dynamical equation (DE), $\ddot{a}=\phi(t,a,\dot{a})$, invariant. The obtained solutions from solving the DEs of the FLRW cosmological model by the ISG-method are explicitly written, so that they are suitable for cosmological applications. Finally, as an application of the solutions we look at the age of universe in the presence of cosmological constant where the dominant matter of the universe is considered to be fluid with the state parameter $w$. In this regard, we calculate the age of universe when the dominant matter is dust.Comment: 33 pages, 1 figure, 2 tables, submitted to journa

Investigation of correlation of the variations in land subsidence (detected by continuous GPS measurements) and methodological data in the surrounding areas of Lake Urmia

Lake Urmia, a salt lake in the north-west of Iran, plays a valuable role in the environment, wildlife and economy of Iran and the region, but now faces great challenges for survival. The Lake is in immediate and great danger and is rapidly going to become barren desert. As a result, the increasing demands upon groundwater resources due to expanding metropolitan and agricultural areas are a serious challenge in the surrounding regions of Lake Urmia. The continuous GPS measurements around the lake illustrate significant subsidence rate between 2005 and 2009. The objective of this study was to detect and specify the non-linear correlation of land subsidence and temperature activities in the region from 2005 to 2009. For this purpose, the cross wavelet transform (XWT) was carried out between the two types of time series, namely vertical components of GPS measurements and daily temperature time series. The significant common patterns are illustrated in the high period bands from 180–218 days band (~6–7 months) from September 2007 to February 2009. Consequently, the satellite altimetry data confirmed that the maximum rate of linear trend of water variation in the lake from 2005 to 2009, is associated with time interval from September 2007 to February 2009. This event was detected by XWT as a critical interval to be holding the strong correlation between the land subsidence phenomena and surface temperature. Eventually the analysis can be used for modeling and prediction purposes and probably stave off the damage from subsidence phenomena

Comparison of psychological health in mothers of diabetic and Leukemic children and control group

Background: Parents' psychological health is one of the most important factors to obtain health in children with chronic disease. Objectives: In this paper, we intended to evaluate and compare psychological health in parents of type 1 diabetes mellitus (T1DM) and Leukemic children with control group and estimate the effect of the type of disease on parents' psychological health and if possible recommend means to improve it. Patients and Methods: Three groups of mothers (30 people per group) were evaluated. T1DM children's mothers, Leukemic children's mothers, and control group were chosen from mothers of children who came to Hazrat Aliasghar Emergency Room without any underlying diseases. The samples were asked to fill SCL-90-R and FBIS questionnaires. In addition, other forms were filled for their demographic characteristics. Results: The abbreviation (GSI) score in Leukemic children's mothers was higher than T1DM children's mothers and both groups had higher GSI compared with the control group. Conclusions: Parental functioning and wellbeing are important aspects of a family adaptation to chronic pediatric conditions. Moreover, psychological interventions were recommended to patients. © 2015, Iranian Society of Pediatrics