The diffusivity of Mn in CdTe, D(Mn), has been measured between 500 and 800 "C under saturated Cd and Te condaions. The variation of D(Mn) with Cd partial pressure was measured at 600 'C. Between 500 and 800 "C D(Mn) = (22.5: 3.30)exp [(-(2.35 for saturated Te, and between 600 and 800 "C for saturated Cd D(Mn) = (1.12:9,12) x 1O3exp(-(2.76i0.18)eV/kT) cm2 s-', These results are consistent with those at 600 "C which show D(Mn) to increase with decreasing Cd partial pressure. It is argued that lhe observed features of D(Mn) can be best accounted for in terms of a V& diffusion mechanism.

Derbendikhan reservoir is located on the south east of Sulaimani province between longitude 35° 6' 35"N and latitude, 45° 41' 20" E, and it is the second largest reservoir in the Iraqi Kurdistan region at an altitude of about 485 m above sea level. More than twenty genera of fishes are endemic to this reservoir, Silurus triostegus is one of them, which was selected to determine the amount of heavy metals that accumulated in the muscle tissue. The results revealed that the metals were accumulated in the following descending order (Fe

Here, the authors report on a novel shielding technique for the fabrication of electrical contacts on exfoliated graphene by sputtering and lift-off process. The technique solves this problem by removing unwanted gold film in patterning contacts and reduces the high contact resistivity typically found in sputtered devices ranging from 260 to 940 kΩ μm induced by sputtered Au on graphene. By using a shielding tube integrated into our sputtering machine and optimizing the sputtering parameters, contact resistivity as low as 1.04 kΩ μm has been achieved. Consequently, the total device resistivity is significantly reduced, and the yield rate of the devices fabrication has also increased from 17% to 90%.

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A single-stage amplifier circuits containing transistor as BJT or FET transistor were designed for the microwave application using S-parameters, and developed as a lumped circuit then converted to its equivalent microstrip distributed circuits on different substrates such as Alumina ( r =9.8) and Beryllia ( r =6.3). The output results as power gain G p , noise figure NF, and stability factor K were obtained. These results were compared with other published worked included circuits having the same conditions. The comparison shows that in case of the feedback applied to the circuit the G p achieved about (~1.5) dB for BJT circuits along (0.6-1) GHz and noise figure increased about double, where for FET circuit the increasing in G p about (7) dB along (2) GHz, and noise figure was less than BJT circuit. The physical characteristics are discussed with respect to substrate and show that the substrate with high permittivity was helpful to reach the higher operating frequency and good power gain values.