A multiplier with good speed performance is a very important unit in the modern microprocessors because the cycle that a multiplier completes one multiplication operation determines the main frequency of the microprocessor. In summing of the last product in the traditional multiplier design, the array or iteration summing method is used, which is not suitable to the design of small or middle scale integration circuit. A 32-bit multiplier is presented in which many methods, such as Booth algorithm, 4-2 compressors, Wallace tree algorithm,and carry-lookahead adder, are applied, which results in high speed performance.
By manufacturing of tens of hot wall hydrogenation reaction chambers, the author has performed study on the merits or the demerits of the sampling methods of the chemical compositions analysis of stainless steel repair welding in the process of present manufacturing equipment and given some advice which offers the reference to the technical designers.
The aging hardening behaviours of the cold-rolled Al–Mg–Si–Sc–Zr alloy were investigated. The microstructure, hardness and electrical conductivity (EC) of the Al–Mg–Si–Sc–Zr alloy were measured. The relationship between the microstructure and the properties of the Al–Mg–Si–Sc–Zr alloy with cold-rolling and aging processes was studied. The result shows that the addition of Sc and Zr elements significantly refines the grains of the Al–Mg–Si alloy during casting. The cold rolling promotes the Al–Sc(Zr) precipitation. The precipitate strengthening increases with increasing roll reduction. The EC of the cold rolling + aging Al–Mg–Si–Sc–Zr alloy increases with increasing rolling reductions. The combination effects of the precipitation hardening and DRX softening during the aging process lead to the similar peak hardness values of around 70 HV of the rolled Al–Mg–Si–Sc–Zr alloy with the different reductions.
When underwater camera is used to carry out the visual inspection after fuel reloading in nuclear power plants, heat exchange between fuel assemblies and water can generate underwater turbulence effect, which causes imaging distortion, and then affects position measurement accuracy of nuclear fuel assemblies. A new online visual inspection method for fuel assemblies in nuclear power plants is proposed in this paper. The method consists of image restoration and deformation inspection. A turbulence image degradation model is established at first. In the model that water turbulence weakly satisfy a Gaussian distribution. A temporal high pass filter by image quality assessment and a mean filter in time domain are used to remove the morphing of acquired original sequence images according to the degradation model. And then a spatial Wiener deconvolution filter is used to remove the image blurring that is caused by the above mentioned mean filter. The next step is using the deformation inspection algorithm to get the fuel assembles precise position. The distance of feature holes (S-hole) is solved by calibrated underwater parametric camera model. The experimental results show that the underwater image restoration method can effectively remove the image morphing that is generated by turbulence effect. The proposed online visual inspection method has a high detection precision. And the average error of the solved feature holes’ distance is less than 0.1 mm when the execution time of the method is lower than 0.5 s.
This essay is on account of the view of the current lack of digital emergency management situation, based on GIS technology platform for digital implementation of emergency management programs. Established Yan Jiao geographic information system database, achieving a visual management Yan Jiao map, achieve the dynamic simulation of the earthquake and fire emergency rescue evacuation routes, achieving the management of emergency preplans, as Yan Jiao disaster prevention and response area treatment provides a strong technical support.
Friction stir processing (FSP) was used to achieve grain refinement on Mg-Al-Zn alloys, which also brought in significant texture modification. The different micro-texture characteristics were found to cause irregular micro-hardness distribution in FSPed region. The effects of texture and grain size were investigated by comparative analyses with strongly textured rolling sheet. Grain refinement improved both strength and elongation in condition of a basal texture while such led to an increment in yield stress and a drop in elongation and ultimate stress when the basal texture was modified by FSP.
The dynamic recrystallization (DRX) behavior and hot workability of Mg–8Gd–4Sm–1Zn–0.5Zr alloys are investigated by the Gleeble‐1500 test machine. The tests are performed at 350–470 °C with a strain rate of 0.002–1 s −1 . The results show that the stress–strain curves exhibit a typical single‐peak DRX behavior. The DRX critical strain model of the alloy is constructed according to the inflection characteristics of the work hardening rate curve. The DRX kinetic model is constructed according to Avrami equation. The 3D processing maps are obtained based on the dynamic material model. The mechanisms of instability regions are investigated by combining the processing map and the microstructural evolution, and the most suitable regions for hot working are identified. The critical strain ε c of the alloy is reduced at higher deformation temperatures or lower strain rates, and the DRX more easily occurs. That is, the material is more suitable for hot working. The optimum domain for hot working of Mg–8Gd–4Sm–1Zn–0.5Zr alloy is the temperature range of 400–470 °C and strain rate range of 0.002–0.05 s −1 .
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