In this paper, we have proved that the lower bound of the number of real multiplications for computing a length 2(t) real GFT(a,b) (a = +/-1/2, b = 0 or b = +/-1/2, a = 0) is 2(t+1) - 2t - 2 and that for computing a l...
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In this paper, we have proved that the lower bound of the number of real multiplications for computing a length 2(t) real GFT(a,b) (a = +/-1/2, b = 0 or b = +/-1/2, a = 0) is 2(t+1) - 2t - 2 and that for computing a length 2t real GFT(a,b)(a = +/-1/2, b = +/-1/2) is 2(t+1) - 2. Practical algorithms which meet the lower bounds of multiplications are given.
The effects of quenching temperature on shape memory effect and microstructure of Fe 18Mn 5Si 8Cr 4Ni shape memory alloy.h.ve been studied. The results show that both the shape recovery ratio and the recovery stra...
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The effects of quenching temperature on shape memory effect and microstructure of Fe 18Mn 5Si 8Cr 4Ni shape memory alloy.h.ve been studied. The results show that both the shape recovery ratio and the recovery strain increased as quenching temperature increased, the amount of stress induced ε martensite in the process of cold work decreased with the increase of quenching temperature, the shape recovery ratio and the recovery strain reached maximum at 650℃, and then decreased rapidly with the further increase of quenching temperature,the stress induced ε martensite wholly disappeared at 1023K. But when the quenching temperature is higher than 1023K, the further increase of quenching temperature had little effect on shape recovery ratio, the amount and size of thermal induced ε martensite would increased with the further increase in quenching temperature. The shape memory effect can be improved by the moderate amount of pre exist ε martensite in the matrix before deforming.
A novel wide-band laser cladding system, withhigh rate of cladding, has been developed in the present work. The system mainly consisted of a 5kW CO2 laser, an automatic powder feeder and a wide-band scanning rotativ...
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A novel wide-band laser cladding system, with high rate of cladding, has been developed in the present work. The system mainly consisted of a 5kW CO2 laser, an automatic powder feeder and a wide-band scanning rotative polygon mirror which can produce a linear or rectangular focused laser beam. Using this system, a Ni-Cr-Si-B alloy powder was cladded on the surface of type 321 austenitic stainless steel in order to improve its wear and corrosion resistance. The pitting corrosion, high temperature oxidation and wear tests were conducted in order to evaluate the properties of the laser cladded layer. The results demonstrated that the cladded layer can significantly improve the adhesive wear and pitting corrosion resistance of the substrate. Moreover, the cladded layer exhibited good oxidation resistance, which is almost the same as that of GMR-235D Ni-based superalloy.
The influence of solid fraction of Al-20Sn alloy mushy on gravity segregation of Sn in casting was studied . The relationship between solid fraction and the temperature of alloy mushy and that between solid fraction o...
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The influence of solid fraction of Al-20Sn alloy mushy on gravity segregation of Sn in casting was studied . The relationship between solid fraction and the temperature of alloy mushy and that between solid fraction of alloy mushy and size of Sn particle in ingot were determined. The results show that the relationship between solid fraction and the temperature of alloy mushy was fs=1683-4.86t+0.003 5t2. The extent of gravity segregation of Sn in casting reduced gradually with the increase of solid fraction of alloy mushy. When solid fraction of alloy mushy was larger than 40%, the gravity segregation of Sn in casting could be removed basically, and the relationship between solid fraction of alloy mushy and size of Sn particle in ingot was s=-0.64fs+70.8.
Mg-9wt%Li-2wt%Zn alloy was prepared and studied in this article. The addition of Ca to the alloy from 0.1wt% to 1wt% can refine the α-Mg and the best effect of refinement occurs when Ca content is 0.4wt%-0.5wt%. The ...
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Mg-9wt%Li-2wt%Zn alloy was prepared and studied in this article. The addition of Ca to the alloy from 0.1wt% to 1wt% can refine the α-Mg and the best effect of refinement occurs when Ca content is 0.4wt%-0.5wt%. The billets can be rolled to thin sheets at room temperature, from which it is obvious that the addition of Ca improves alloys ormalin. while it decreases with the excess addition of Ca. The results also show that the ultimate tensile strength （UTS） and yield strength （yS） of the alloy with lwt% Ca may rise by 28% and 25%, respectively, however, the elongation decreases. It is clarified that the adsorption of proper Ca on the grain boundaries refines α-Mg and improves the tensile properties, but the presence of excess Ca and stable Ca2Mg6Zn3phase worsens the elongation.
high-temperature AC magnetic properties for （Fe0.5Co0.5）73.5Cu1Nb3Si13.5B9 alloy annealed at various temperatures have been investigated using an impedance analyzer. Annealing temperature Ta has obvious effects on h...
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high-temperature AC magnetic properties for （Fe0.5Co0.5）73.5Cu1Nb3Si13.5B9 alloy annealed at various temperatures have been investigated using an impedance analyzer. Annealing temperature Ta has obvious effects on high-temperature AC magnetic properties of the alloy. The hopkinson peak appears only in the amorphous alloy when Ta≤703K. As Ta increases above 733K, the real part of the complex initial permeability μi′descends gradually, μi′decreases more slowly with temperature in the high temperature range. The high-temperature （about 750K） AC initial permeability for the alloy annealed at Ta= 763K has been found to maintain a stable high value of 950 up to a frequency of- 1 × 10^5hz. Partial substitution of Co for Fe in the F73.5Cu1Nb3Si13.5B9 alloy leads to an increase of around 110K of the Curie temperature of the amorphous phase, much higher than Ge-containing Finemet alloy.
The effect of quenching temperature on the recovery stress of Fe 18Mn 5Si 8Cr 4Ni shape memory alloy.h.s been studied. The results show that both the maximum recovery stress σ h in heating and the recovery stress σ ...
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The effect of quenching temperature on the recovery stress of Fe 18Mn 5Si 8Cr 4Ni shape memory alloy.h.s been studied. The results show that both the maximum recovery stress σ h in heating and the recovery stress σ c at room temperature after heating increased as increasing quenching temperature increased, both σ h and σ c reached maximum at 650℃, and then decreased rapidly with the further increase in quenching temperature,but the descent degree of σ c was far bigger than that of σ h; When the quenching temperature is higher than 850℃, the further increase in quenching temperature had little effect on them; At random quenching temperature, σ c was far bigger than σ h.
Proteases, such as trypsin, are essential for extracting collagen in various industrial applications. The potential applications of rare earth nanomaterials, specificallyyttrium nanoparticles, have attracted signific...
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Proteases, such as trypsin, are essential for extracting collagen in various industrial applications. The potential applications of rare earth nanomaterials, specifically yttrium nanoparticles, have attracted significant interest across various fields due to their distinctive characteristics, including high dielectric constant and thermal stability. Biomineralization has emerged as a promising approach to synthesize protein-inorganic nanomaterials with hierarchical structures and desired functions. In the present investigation, a novel protease-templated biomineralization strategy was developed for synthesizing protease-（Nh4）2y3F11·h2O hybrid nanomaterials using a one-pot method under very mild conditions. For modifying the morphologies of（Nh4）2y3F11·h2O throughout biomineralization, protease has been demonstrated to be a highly promising biotemplate. Protease was utilized as a template for morphological control in the biomineralization procedure, which resulted in a gradual transformation of the initially formed（Nh4）2y3F11·h2O octahedral structures into uniform nanospheres. The applicability of this approach was supported by successfully utilizing various proteases to synthesize protease-（Nh4）2y3F11·h2O hybrid nanospheres. In addition to a strong and desirable luminescent signal, these hybrid nanospheres demonstrated extensive recycling because of their high enzymatic activity, stability and durability. The protease-mediated biomineralization approach offers an easy and robust approach to develop innovative protease-inorganic composites. Its moderate reaction conditions and simple operation render it a viable tool for developing stable and reusable enzyme reactors in various industrial applications.
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