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Influence of metallic properties on the fracture characteristics of Al2O3/Ti/Ni-laminated composites
Quan Liu Ke Xie Hongyan Xia Yifan Wu Weiguo Xu Minkun Jian Jianping Lin Mi Lu Guanjun Qiao 《International Journal of Applied Ceramic Technology》2022,19(6):3279-3287
The mutual confinement of ceramics and metals in laminated composites tends to change the original properties of ceramics and metals. In this study, two kinds of laminated composites, Al2O3/Ti and Al2O3/Ti/Ni, were prepared. Three-point bending experiments revealed that Al2O3/Ti underwent brittle fracture after elastic deformation. The fracture morphology analysis revealed that the Ti in Al2O3/Ti became brittle due to the formation of columnar crystals. The temperature gradient perpendicular to the direction of laminations during preparation was responsible for the formation of columnar crystals. The force–displacement curves of the Al2O3/Ti/Ni combine the properties of elastic deformation of ceramics and plastic deformation of metals. The reason why the Al2O3/Ti/Ni did not fracture completely in the bending experiments is that Ni maintained the toughness, and there is a good interfacial bond among Al2O3, Ti, and Ni. The indentation crack analysis revealed that cracks have long transverse propagation and short longitudinal propagation in both laminated composites. Finite element analysis revealed that this was due to compressive stress in the Al2O3 layer and tensile stress in the metal layer. This compressive stress consumes the crack energy in the longitudinal direction and stops the crack in the metal layer. The brittle to ductile gradient transition among Al2O3, Ti, and Ni, combined with the guidance of crack propagation direction by the interfacial layer, enhances the ability of Al2O3/Ti/Ni to resist damage. 相似文献
3.
Comparison of the crystalline properties and structural changes of starches from high-amylose transgenic rice and its wild type during heating 总被引:1,自引:0,他引:1
Cunxu Wei Fengling Qin Weidong Zhou Bin Xu Chong Chen Yifang Chen Youping Wang Minghong Gu Qiaoquan Liu 《Food chemistry》2011
A transgenic rice line (TRS) enriched amylose and resistant starch has been developed by antisense RNA inhibition of starch branching enzymes. In this study, gelatinisation and crystalline properties, swelling power, water solubility, morphological and structural changes of starches from TRS and its wild-type Teqing (TQ) were carefully investigated during heating. Compared to TQ, TRS starch showed higher gelatinisation temperatures, lower gelatinisation enthalpy and swelling power. Morphological and structural changes showed that TQ starch drastically swelled after 70 °C, then gradually disrupted with increasing heating temperature. The surrounding band of TRS starch restrained granule swelling, though the subgranules disrupted to form the cavity. The results of spectroscopic analyses indicated that A-type crystalline of TQ changed to amorphous starch after 75 °C, while C-type crystalline of TRS gradually changed to B-type crystalline after 75 °C, then became amorphous starch at 95 °C. These results add to our understanding of the effect of heating on the high-amylose rice starch. 相似文献
4.
《Ceramics International》2020,46(3):2624-2629
TaC/SiC composites with 5 wt% SiC addition were densified by plasma-activated sintering (PAS) at 1500–1800 °C for 5 min under 30 MPa. The effects of plasma-activated sintering on microstructures, densification and mechanical properties of the composites were investigated. The results showed that TaC/SiC composites achieved a relative density more than 99% of the theoretical density at 1600 °C. A low eutectic liquid phase generated by the oxide on the particle surface was observed in the composite to realize a relatively low temperature sintering densification. While the TaC particle size decreased insignificantly with increasing sintering temperature, the transformation of morphology of SiC particles changing from equiaxed to elongated grain was activated, accompanying with a slight particle size decreasing of the SiC phase, thus promoting a relatively high flexural strength of 550 MPa under 1800 °C. Besides, some ultra-fine 2 nm Ta2Si was observed in the glassy pockets, strengthening the amorphous phase and thus increasing the flexural strength. 相似文献
5.
电网调度自动化系统的开发应用 总被引:1,自引:0,他引:1
电网调度自动化系统是利用现代化先进的电子技术,计算和网络技术和通信技术,将网上的实时数据,离线数据、电网结构、设备参数和地理信息等多种信息进行综合处理和集成,形成调度自动化系统。从结构上分为变电所数据采集(RTu)、通信通道、计算机系统主站三个部分。目前、盘曙电网35座变电所已经实现电网调度自动化,其中微机综合自动化变电所10座,老式变电站25座。运行可靠稳定,安全运行水平显著提高,实现了调度管理自动化。 相似文献
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个人通信接入系统(PAS)的关键技术 总被引:1,自引:0,他引:1
在介绍个人通信接入系统(PAS)的体系结构的基础上,进一步阐述了个人通信接入系统的几点关键技术。 相似文献
8.
为解决含锰工业废水对环境、土壤及生物带来的危害。研究采用吸聚合硫酸铝作为附剂,希望能找到最佳吸附条件,同时为聚合硫酸铝的综合利用提供更多机会;采用EDTA滴定法,对含锰废水进行了吸附研究,模拟测定了影响聚合硫酸铝吸附特性的两种因素:滤料投加量、吸附时间。结果表明:随着投加量增加,Mn2+去除率提高,单位吸附量线性下降;随着吸附时间延长,Mn2+去除率提高,超过80min后提高幅度变缓,吸附过程符合二级动力学模型。采用聚合硫酸铝吸附含锰工业废水在适当工艺条件下可以有很好的处理效果。这种方法较简便,成本低廉,能达到以废治废的目的。 相似文献
9.
An improved Langmuir method is described and applied to produce transparent, conductive and flexible single layer of multiwall carbon nanotubes. This paper presents properties of multiwall carbon nanotubes spread on water subphase and in a form of Langmuir–Schaefer layers on a quartz plate and on flexible polymeric foil. The results show very high homogeneity of the monolayers on a very large area obtained with the use of the proposed modified Langmuir method and indicate their relatively high radiation transmission and electrical conductivity. Laser scanning confocal and scanning electron microscopic images of the layers are presented. The microscopic visualization of the nanolayers is supported by spectroscopic studies (transmittance, photoacoustics) in the range from ultraviolet to mid-infrared. Moreover, electric measurements (current versus voltage characteristics) of the carbon material on the polymeric foil are presented.The obtained results of the investigated multiwall carbon nanotubes are discussed in a view of potential application in optoelectronics. 相似文献
10.
Many yeast peroxisome biogenesis mutants have been isolate in which peroxisomes appear to be completely absent. Introduction of a wild-type copy of the defective gene causes the reappearance of peroxisomes, despite the fact that new peroxisomes are thought to form only from pre-existing peroxisomes. This apparent paradox has been explained for similar human mutant cell lines (from patients with Zellweger syndrome) by the discovery of peroxisomal membrane ghosts in the mutant cells (Santos, M. J., T. Imanaka, H. Shio, G. M. Small and P. B. Lazarow. 1988. Science 239 , 1536–1538). Introduction of a wild-type gene is thought to restore to the ghosts the ability to import matrix proteins, and thus lead to the refilling of the peroxisomes. It is vitally important to our understanding of peroxisome biogenesis to determine whether the yeast mutants contain ghosts. We have solved this problem by introducing an epitope-tagged version of Pas3p, a peroxisome integral membrane protein (that is essential for peroxisome biogenesis). Nucleotides encoding a nine amino acid HA epitope were added to the PAS3 gene immediately before the stop codon. The tagged gene (PAS3HA) was inserted in the genome, replacing the wild-type gene at its normal locus. It was fully functional (the cells assembled peroxisomes normally and grew on oleic acid) but the expression level was too low to detect the protein with monoclonal antibody 12CA5. PAS3HA was expressed in greater quantity from an episomal plasmid with the CUP1 promoter. The gene product, Pas3pHA, was detected by immunogold labelling on the membranes of individual and clustered peroxisomes; the clusters appeared as large spots in immunofluorescence. PAS3HA was similarly expressed in peroxisome biogenesis mutants peb2 and peb4, which lack morphologically recognizable peroxisomes. Gold-labelled membranes were clearly visible in both mutants: in peb2 the labelled membrane vesicles were generally much smaller than those in peb4, which resembled normal peroxisomes in size. 相似文献