Effect of substrate rotation on structure, hardness and adhesion of magnetron sputtered TiB2 coating on high speed steel

Titanium diboride (TiB₂) coatings have been deposited on stationary and rotating high speed steel substrates by magnetron sputtering of a TiB₂ target. The structure and hardness of the coatings and the coating–substrate adhesion have been investigated by X-ray diffraction, field emission scanning electron microscopy, nanoindentation and microscratch tests. The results show that substrate rotation has a significant effect on these structural and properties features. It was found that, with substrate rotation, the TiB₂ coating exhibits a columnar structure with random orientation and relatively low hardness and coating–substrate adhesion. On the other hand, without substrate rotation, the TiB₂ coating shows a strong (001) texture with dense, equiaxed grain structure. The hardness and coating–substrate adhesion of the coatings deposited on stationary substrates are much higher than those deposited on rotating substrates. The observed phenomena are discussed in terms of the energy of the sputtered flux, which varies with the substrate–target distance during deposition.     

Performances of SDCM and DCM walls under deep excavation in soft clay: Field tests and 3D simulations

This study presents the results of full-scale tests and three-dimensional finite element analyses of deep cement mixing (DCM) and stiffened deep cement mixing (SDCM) columns under lateral loads and DCM and SDCM walls under deep excavation in soft clay. The DCM walls used in this study comprised one, two and three rows of DCM columns, whereas the SDCM walls consisted of only one row of DCM columns with steel H-beams inserted in either all DCM columns or in alternating DCM columns. The measured and simulated results are presented in terms of profiles of lateral displacement, settlement and bending moment.     

Ti/TiB2多层镀层的组织和性能研究

为了进一步提高超硬TiB2镀层与基体的结合力,采用磁空溅射法在高速钢表面上制备了多层相间的Ti/TiB2超硬镀层.利用多种实验方法测试和研究了镀层的组织结构,形貌,表面粗糙度,硬度和与基体的结合力.结果表明,镀层的Ti/TiB2相间层数对这些性能有很大的影响.当层数从二逐渐增加到十二,TiB2镀层的（001）织构逐渐消失而变成无择优取向,镀层表面粗糙度增加,但镀层硬度基本不变.只有当层数为十二时,镀层硬度才明显降低.结果也表明,多层镀层可有效地提高镀层与基体的结合力,并存在着一最佳的多层结合.本文也对多层结构对其它组织和性能特征的影响进行了分析.     

用NMR研究洋葱碳吸附水后的抗磁性（英文）

对洋葱状碳缺陷位吸附水分子的1H化学位移进行测试,并比较块状水和石墨烯、氧化石墨烯和纳米金刚石吸附水的化学位移。纳米金刚石和氧化石墨烯绝缘体的1H共振位置与块状水接近,然而石墨烯和洋葱碳吸附水呈现明显的化学位偏移,这是由导电的石墨烯片层抗磁屏蔽效应所致。质子的化学位移和抗磁性之间存在显著的相关性。     

Analysis of the informativeness of piezoelectric presure transducers by means of a generalized performance index

A comparison of piezoelectric pressure transducers produced by different Russian and foreign firms is carried out using a generalized performance index. __________ Translated from Izmeritel’naya Tekhnika, No. 6, pp. 27–29, June, 2008.     

Allowance for gas solubility and the finite strength of vacancy sinks in the sintering of a ceramic

The process of diffusional evolution (shrinkage or growth) of gas-filled pores in a hot-pressed ceramic is analyzed, assuming that the gas is soluble in the matrix. It is additionally assumed that the strength of vacancy sources and sinks is finite. An equation is derived for the porosity of the ceramic at a late stage of sintering. N. N. Ts. “Kharkov Physicotechnical Institute.” Translated from Poroshkovaya Metallurgiya, Nos. 5–6, pp. 24–32. May–June, 1998.