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SUN Liling DONG Lianke ZHANG Jishan TANG Yajun ZHANG Jinghua HU Zhuangqi Institute of Metal Research Academia Sinica Shenyang China SUN Liling Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1993,6(5):291-295
The morphology of solid/liquid interface of a directionally solidification process is describedby means of fractal analysis,and the relations among the fractal dimension of the solid/liq-uid interface,solidification rate,dendrite arm space and the phosphorus content of the test al-loys have been given.It was found that the increase of the solidification rate and the phos-phorus content of the test alloy will lead to a increase,following the regularity of exponentialfunction,in the fractal dimension of solid/liquid interface.Furthermore,by combining thefractal theory and the thermodynamic principle with the measured results,it has been provedthat the fractal dimension is not only a kind of simple geometrical parameter used in des-cribing irregular geometry,but also a state function depending the change of solidificationparameters and chemical compositions. 相似文献
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This imaging technique is used for approximate interpretation of TEM data including ungrounded loopsource and grounded line source soundings.Loop source data can be collected as central-loop soundings or asout-of-loop soundings with a short or long offset configuration.The imaging method is based on the same princi-ple as that employed by Fullager(1989),with apparent resistivities computed directly from time-derivative data,db/d,and then associated with depths according to image theory. 相似文献
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为应用d-电子合金设计理论(或新相分计算法(New PHACOMP))设计发展新型抗热腐蚀单晶高温合金,首先对高Cr抗热腐蚀IN738LC系列合金Ni—16Cr—9.5Al—4.0Ti-8.0Co—0.55Nb—0.06Zr—0.05B—0.47C-Ta—W—Mo(at-%)的相稳定性进行了综合评价得出抑制σ相析出的稳定性临界条件为Mdt<0.991或Mdγ<0.93同时证明这两个临界电子参数具有等价性,可以用Mdt代替Mdγ简化合金设计过程.这一结果可适用于其它高Cr系列抗热腐蚀镍基合金的d-电子合金设计 相似文献
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喷射成形CuCr25合金触头材料的制备及致密化处理 总被引:3,自引:1,他引:3
利用喷射成形技术制备了CuCr2 5合金触头材料 ,研究了雾化压力对显微组织、致密度和收得率的影响 ,对制得的沉积坯件进行了热锻压和热等静压致密化处理 ,并测试了触头材料的密度、硬度和电导率。研究结果表明 :最合适的雾化压力为 0 .6MPa ,沉积坯件经过 95 0℃锻压后再在 10 70℃ ,2 0 0MPa下热等静压 8h ,可以得到全致密的触头材料 ,铬颗粒平均直径小于 10 μm ,硬度达 10 0HB ,电导率 2 5~2 9Ms·m- 1 ,说明致密化处理后的喷射成形CuCr2 5合金是一种优良的触头材料。 相似文献
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The effects of pH on the yield stress and zeta potential behaviour of α-Al2O3 dispersions with addition of d-, l- and racemate (DL) malic acids were evaluated. Conformational structures and intramolecular hydrogen bonding of the adsorbed malic acids obtained via MM2 modeling were used to explain the surface forces operating in the dispersions. We found that the yield stress-pH behaviour is almost identical for d-, l- and racemate malic acids. At low surface coverage of adsorbed malic acid, the maximum yield stress was reduced by as much as 55%. At complete surface coverage the reduction decreased to ~40%. MM2 modeling showed the presence of intramolecular hydrogen bonding between the hydroxyl and the (free) charged carboxylate group within the malic acid molecule. Intra-molecular hydrogen bonding and the high number of strongly bound water molecules (hydration number of malic di-ionic species) were likely responsible for the di-ionic malic acid species acting as a very effective steric agent. At complete surface coverage, the inter-molecular hydrogen bond formed between the layers of adsorbed malic acid, is responsible for the small rise in the maximum yield stress. Racemate malic acid produced a smaller maximum yield stress at complete surface coverage compared to the pure enantiomers. This may be related to the two different types of hydrogen bonds found in the racemate. Only one type is found in the pure enantiomers. 相似文献
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A reusable capacitive immunosensor with a novel immobilization procedure based on 1,6-hexanedithiol and nano-Au self-assembled layers 总被引:2,自引:0,他引:2
A novel immobilization procedure of antibody proteins for capacitive immunosensing, based on thiolor sulfur compound (1,6-hexanedithiol, HDT) and colloid Au layers is proposed. The insulating organic monolayer film was first formed by the spontaneous assembly of HDT from solution onto gold. When these thiol-rich surfaces are exposed to Au colloid, the sulfurs form strong bonds to gold nanoparticles, anchoring the clusters to the electrode substrate. After the assembly of gold nanoparticles layer, the original formed organic thiols surface was restored, and a new nano-Au surface was obtained. Thus, the antibody could be immobilized through electrostatic adsorption between nano-Au and the antibody proteins. After use, the formed immunocomplex layer can be rinsed out, via a saline solution with extreme pH. Therefore, the immunosensor can be regenerated repeatedly, highlighting a clear advantage of this new approach with respect to classical immunoassays employing covalent immobilization. 相似文献