钢筋-混凝土预制板在使用阶段的墙体建筑中具有良好的稳定性,具有较高的承载力。但在制作和运输中易出现裂纹,为防止裂纹的出现,采用断裂力学的观点对钢筋-混凝土预制板的力学性能,断裂进行强度估算,并给出公式。
There are 27 user-controllable LEDs on the DE2-70 board. Eighteen red LEDs are situated above the 18 toggle switches, and eight green LEDs are found above the pushbutton switches (the 9th green LED is in the middle of the 7-segment displays). Each LED is driven directly by a pin on the Cyclone II FPGA; driving its associated pin to a high logic level turns the LED on, and driving the pin low t