رضا مردانی

In this paper, three frequency divider structures for low-power and high-speed applications are proposed. In this design, true single phase clock (TSPC) flip-flop, AND modified gate diffusion input (AND_m-GDI) gate and multiplexer modified gate diffusion input (MUX_m-GDI) gate are used. This technique provides the dividers with reduced power consumption and high speed. Also, these blocks have a good performance at low supply voltage, which has a great effect on power consumption reduction. In order to improve the output swing in m-GDI cells under the mentioned supply voltage, complementary transistors have been used. The ÷2/3, ÷3/4 prescalers and ÷23/24 frequency divider are designed. Finally, according to the techniques used in this paper, a two-level frequency dividers with different values is proposed. The proposed frequency dividers are able to operate to 4 GHz, and their figure-of-merit (FoM) values in compared to other frequency dividers are improved, considerably. The maximum frequencies for the 2/3 and 3/4 are 4.5 GHz and 5 GHz, respectively. Average power consumption at frequency of 2.4 GHz, for the divider 2/3 and 3/4 are equal to 15.25 µW and 16.37 µW, respectively. The FoM values for the proposed frequency dividers in compared to others are considerably improved. Obtained results are based on post layout simulations performed with 65 nm CMOS technology.

A silicon substrate was developed for use in thermoacoustic motors as heat exchangers. Acetylene gas (C2H2) as a carbon source of argon gas (Ar) as a carrier gas for hydrogen gas (H2) is used to recover nanoparticles and iron nanoparticles as a catalytic source for carbon nanotube array growth. The reaction was carried out in a 48 cm long quartz tube and the gases were injected with a specified flow rate. Increasing the growth time from 10 to 30 min, there was little change in the diameter distribution and density of the synthesized carbon nanotube arrays. However, the thickness of the arrays increased from 15.62 to 16.76 μm. Carbon nanotubes grown at 30 min had better growth. The thicknesses (lengths) of the carbon nanotube arrays synthesized at temperatures of 750 and 800 °C were 75.42 and 60.98 μm, respectively. In general, the samples synthesized at optimum growth time and temperature of 30 min and 750 °C on the layered silicon substrate (with iron nanoparticles) by magnetic sputtering were quite desirable for use as a thermocouple converter.

In this article, a field study on the subject of drug and addiction among young people in Khorramshahr city in 2016 has been conducted.  

The theoretical framework of this study is an integrated two theories of Hirschi's social control and the differences between Sutherland and Chris, to determine the causes of both internal and external factors affecting the crime. 300 questionnaires were distributed to drug addiction centers, prisons and low-level families. The four variables related to delinquent acts and independent variables included personal characteristics, family life and addiction, family support system, beliefs and practices, the relationship between delinquents and hobbies, and spending leisure time and control of the situation and supervision.

The results of multiple regression analysis showed that only three factors of dependency of family members addiction with youth addiction, proper social and social prevention, youth addiction, and parental and non-victim abuse and addiction and youth addiction have been affected by the severity of delinquency and can explain it.

Findings show that the most important personal, social and family factors in the tendency of youth to use drugs in Khorramshahr city are: the presence of symptoms of depression, divorce and family disputes, parents' addiction, socializing with infectious persons, smoking and academic failure which can be taught by skills Life, the development of family counseling, the creation of centers for art, cultural and technical training, prevented the spread of this problem.

In this paper sound generation by laser pulse irradiated on a solid block is investigated. After an introduction to known mechanisms and main equation of laser acoustics, the laser pulse profile of NdYAG laser by straight radiation on a photo-resistor was recorded and the profile was substituted as an optoacoustic source in related equation of sound evolution. Finally the solution of numerically solved equation and measured generated sound were compared. Results show that there exists direct relationship between generated sound pulse width and laser pulse width. Furthermore there exists reverse relationship between generated sound pulse width and solid block thickness. In addition, results of simulation and experimental data measured by laser microphone with photo-resistor detector are compared by obtained sound spectrum from Spectrogram which confirm previous theoretical and experimental data. Finally general rule of the similarity of sound pulse profile and sound generator laser pulse profile are observed in this experiment.

In this paper a Class-D amplifier is proposed to drive piezoelectric loads considering efficiency, linearity and electromagnetic interference issues. The proposed class-D amplifier is based on pulse-width-modulation (PWM) battery-fed. The amplifier not only supplies high voltage power but also utilizes dc-to-dc chopper to make electric isolation and reduce the output distortion. Using isolation dc chopper, causes amplifier isolation from the battery and in turn leads the circuits to be secured from the output distortions. The proposed class-D amplifier consists of a close-loop H-bridge ac-to-dc converter to improve the gain and reduce the output distortion. The amplifier is linear and the achieved output voltage THD is less than 0.9% by a band-pass filter. The proposed amplifier is analyzed in different modes precisely and its operation is simulated. Main features are electric isolation from the source, linearity, fast response and sufficient band-pass.

The sound waves caused by the engine's operation and the rest of the floating interior equipment, if passed through a composite body, are detected by floating sea mines, especially acoustic mines. As a result, controlling and reducing the amount of sound transmitted from the floating body in operating parts is critical. In this study, due to the importance of passing the acoustic waves from the body of the particular vessels, the acoustic waves of different composite materials with layered and sandwich structures in water were evaluated and compared theoretically and experimentally. Five composite sheets were made to perform the tests. After placing them in water, the transmittance of acoustic waves per page was measured separately in two different frequency ranges. The first example is a sandwich panel with a plating foam core and glass and carbon fiber sheaths; the second specimen has a layered structure consisting of several layers of glass fiber, a third specimen like a second but with more layers, a fourth sample of sandwich panels with white wood core and shells. The fiberglass and final specimen are selected as a fourth sample but with a doped foam core. In the end, the results of the pages are presented in the form of a diagram and the necessary and applied comparisons between the experimental results and the theoretical calculations were made. The first and last samples are more absorbent than other specimens, even the first carbon-fiber sample is slightly better than the last one. It should be noted that the obtained results play an important role in the selection of composite materials and the design of a floating composite fuselage.

In this paper, the effect of temperature on electrical impedance, resonant frequency and antiresonance of a plural acoustic piezoelectric transducer has been investigated. These effects are being studied in the design of electronic circuits connected to the high-power Tonpillos projector that is used to clean oil pipelines using acoustic waves. A special oil storage tank, converter, heating equipment and control were designed and constructed. Two sensitive thermometers, oil temperature and converter are accurately measured. The impedance behavior was performed in the temperature range of 20-120 ° C and in the frequency range 18-25 kHz. The results show that with increasing temperature, the frequency of the resonance is 480 Hz and the antiresonance of 400 Hz is decreased. Changes in the magnitude of the impedance increase of 43 ohms in the resonant frequency and a decrease of 965 ohms at the antiresonance frequency. The results of the experiments show that impedance, resonant frequency and antiresonance are strongly dependent on temperature. This could be considered for future research on increasing the acoustic efficiency of high-capacity converters in cleaning systems, especially in oil pipelines.

Infertility of couples has many negative psychological and social consequences for society, and the physicians always seek to find the causes and treatment for this problem. Detection and treatment of Uterine and tubal causes can reduce the incidence of infertility. Therefore, this study was performed with aim to assess abnormal findings of hysterosalpingography (HSG) in infertile couples.
This descriptive study was performed on 308 women referring to the radiology clinic of Imam Reza hospital for hysterosalpingography between 2008 and 2015. A checklist was prepared from data recorded in files and reports of radiography. Data were analyzed by SPSS software (version 16).
During the study period, 308 infertile women referred with mean age of 30.5±6.4 years and mean duration of infertility of 2.4±2.8 years. 54% of patients had primary infertility and 46% secondary infertility. The most common pathology among the infertile women was tubo-peritoneal factor (72.5%). In 38 cases (10%), association of several other pathologies was observed. In patients with pathologies of the uterus, uterine horns (Bicornate) was the most common abnormal finding.
In hysterosalpingography of infertile women, the most common causes of infertility were tubo-peritoneal, Multifactorial and uterine factors, respectively.

In this research, magnetic anisotropy of Co68.15Fe4.33B12.5Si15 microwires were investigated. For this purpose, VVSM (Vector Vibrating Sample Magnetometer) analysis, which measures the transverse components of the magnetization simultaneously with the longitudinal one, was used. The magnetic field is applied in different directions with respect to cylindrical axis of wire and magnetization were recorded along X and Y direction. The component of magnetization along X direction decreases with increasing angle, while for Y component the magnetization increases with increasing angle of applied field. The results are explained in terms of unusual magnetic domain structure of wires.

preeclampsia is associated with various maternal and neonatal outcomes such as intra-uterine growth retardation, preterm labor and increased risk of fetal mortality. It seems that increased uterine vascular resistance is associated with higher risk of preeclampsia progression. This study was performed with aim to investigate uterine artery indexes in Doppler sonography for predicting neonatal outcome in preeclamptic pregnancies.
this prospective study was conducted on 46 pre-eclampsia and 74 normal pregnant women referred to Emam Reza and Omalbanin hospitals in 2014. Trans-abdominal Doppler sonography was conducted between 26-36 weeks of pregnancy at supine position and Doppler signals of uterine artery indexes were evaluated and after delivery, neonatal complications were added to the form of evaluation. Data was analyzed by SPSS software (version 16) and T-student, Chi-square and Mann-Whitney tests. P The highest sensitivity, specificity and positive predictive value for the mean Pulsatility index of uterine artery in women with preeclampsia in predicting of low birth weight infants were 51.7% and 90.9% and 93.7%, respectively. The highest sensitivity and positive predictive value of uterine artery resistance index in predicting of low birth weight infants were 62% and 94.7%, respectively. Also, mean uterine artery resistance index in prediction of all adverse pregnancy outcomes had high specificity.
Although uterine artery indexes in Doppler sonography has no high sensitivity to predict neonatal outcomes, but their abnormal range can predict low birth weight.