m. fakharzadeh

In Time modulated arrays (TMAs), a switch is used instead of a phase shifter, which reduces the area, complexity, power consumption and the overal cost of the array. The TMA uses the switch as a control element for array weighting for the purpose of beam forming and beam steering. To lower the IC cost, the IC is designed to be as compact as small as possible. Moreover, the inexpensive CMOS 180 nm technology of TSMC is used for IC fabrication. The designed SPDT switch has 1.85 dB loss at 33 GHz, more than 17 dB isolation in Ka-band, and its area is 0.086 mm2. Compared to other switches designed in CMOS180 nm, this work has the lowest loss and area (up to now), and covers Ka-band completely. Another critical element of an array is a power combiner/divider with minimum area. Because this array has 4 elements, it needs a 4-way power divider. Four switches and power divider form a TMA IC, which covers 26.5 to 37.6 GHz with an area of 0.7 by 1.48 mm2. The power consumption of the array is zero since all the elements are passive and do not consume any power.

Depression is one of the most common mental diseases that it is not limited to a special time، place and the person and encompasses all the groups and levels of community. The most harmful effect of long time stress is reported to be the impairment in learning and thinking capabilities. The social supports reduce the vulnerability of people against stress، depression and other physical and mental diseases. The goal of current study was to determine effective factors on depression، perceived stress and perceived social support and their relationship among students living in dormitories of Shahid Beheshti University of Medical Science

In the cross-sectional study، participants included 390 students who lived in the dormitories of Shahid Beheshti University of Medical Science. They were selected through simple random sampling method in 2 dormitories (sisters and brothers'' dormitories). The questionnaires of depression (Beck)، multidimensional scale of perceived social support، and perceived stress scale were completed by the students. Data were analyzed by SPPSS V. 16 software. The descriptive statistics، one way ANOVA، correlation coefficient، independent sample t-test، Chi square and Fisher exact test were used for analyzing data with the confidence level 0. 05.

Job and academic status were the sources of stress in 30. 5 percent of students. The mean of perceived stress score، perceived social support score and depression score were 26. 84±8. 27، 28. 32±9. 56 and 12. 1±9. 02، respectively. Also، 49. 7 percent of students had different degrees of depression. There was a significant relationship between perceived stress، perceived social support and depression (P<0. 001). Discussion &

Since a half of the students were afflicted with depression، paying attention to this problem is very necessary and important. It is suggested that the counseling sessions، promoting students into team working، and participating students in extra programs affairs be carried out for increasing the social support and decreasing the stress and depression.