Extremely low threshold InGaSsp/InP DFB PPIBH laser diode
We report on an extremely low threshold InGaAsP/InP DFB laser realized by an MOCVD/LPE hybrid process.
Low-threshold (3.2 mA per element) 1.3 mu m InGaAsP MQW laser array on a p-type substrate
A low-threshold 1.3- mu m InGaAsP MQW laser array was fabricated on a p-type InP substrate taking compatibility with n/p/n-type laser-driver circuits into account. The laser has a p/n-type current-blocking structure and is made entirely by metal-organic chemical vapor deposition (MOCVD). A 10-channel laser array with a threshold current as low as 3.2+or-0.2 mA (per element) and a slope efficiency of 0.27+or-0.01 W/A is obtained.<<ETX>>
Experimental study on bond behavior between high-strength grout and deformed steel bars
Abstract Engineers use high-strength grout to connect precast concrete members for its low shrinkage and good fluidity. This paper designed 87 central pull-out specimens using the control variable method to investigate the influence of factors on the rebar-grout bond property such as compressive strength, steel grade, bar diameter, transverse stirrups, and bond length. The test result showed that improving grout compressive strength (85.8 MPa–122.7 MPa) cannot improve the bond strength, which was different from the previous conclusions of concrete pull-out tests. Simplified formulas were presented for calculating the characteristic values of bond strength, residual strength, peak slip, and relative slip of load-holding platform based on parameter analysis. Then, a constitutive model was proposed to predict the full-range bond stress-slip curve of high-strength grout and steel bar specimens from bearing to failure. Finally, FEA models were established to evaluate the applicability and accuracy of the constitutive model.