Wire Bow In Situ Measurement for Monitoring the Evolution of Sawing Capability of Diamond Wire Saw during Slicing Sapphire.

Electroplated diamond wire sawing is widely used as a processing method to cut hard and brittle difficult-to-machine materials. Currently, obtaining the sawing capability of diamond wire saw through the wire bow is still difficult. In this paper, a method for calculating the sawing capability of diamond wire saw in real-time based on the wire bow is proposed. The influence of the renewed length per round trip, crystal orientation of sapphire, wire speed, and feed rate on the wire sawing capability has been revealed via slicing experiments. The results indicate that renewing the diamond wire saw, and reducing the wire speed and feed rate can delay the reduction in sawing capability. Furthermore, controlling the value of renewed length per round trip can make the diamond wire saw enter a stable cutting state, in which the capability of the wire saw no longer decreases. The sawing capability of diamond wire saw cutting in the A-plane of the sapphire is smaller than that of the C-plane, and a suitable feed rate or wire speed within the range of sawing parameters studied in this study can avoid a rapid decrease in the sawing capability of the wire saw during the cutting process. The knowledge obtained in this study provides a theoretical basis for monitoring the performance of the wire saw, and guidance for the wire cutting process in semiconductor manufacturing. In the future, it may even be possible to provide real-time performance parameters of diamond wire saw for the digital twin model of wire sawing.

Investigation of the Anisotropy of 4H-SiC Materials in Nanoindentation and Scratch Experiments.

Silicon carbide is an ideal material for advanced electronics, military, and aerospace applications due to its superior physical and chemical properties. In order to understand the effect of crystal anisotropy of 4H-SiC on its processability, nanoindentation and nanoscratch tests on various crystallographic planes and orientations were performed and the results outlined in this paper. The results show that the C-plane of 4H-SiC is more rigid, while the Si-plane is more elastic and ductile. Better surface quality may be obtained on the Si-plane in nanoscale abrasive machining. The maximum lateral force, maximum residual depth of the scratch, and maximum crack width on the C- and Si-planes of 4H-SiC are significantly periodic in crystallographic orientations at 30° intervals. The scratch along the <112¯0> direction is more prone to crack expansion, and better machined surface quality is easy to obtain along the <101¯0> directions of C- and Si-planes.

Reactive Infiltration and Microstructural Characteristics of Sn-V Active Solder Alloys on Porous Graphite.

In this work, the reactive wetting and infiltration behaviors of a newly designed Sn-V binary alloy were comprehensively explored on porous graphite for the first time. It was discovered that 0.5 wt.% addition of V can obviously improve the wettability of liquid Sn on porous graphite and the nominal V contents in Sn-V binary alloys has minor effects on the apparent contact angles wetted at 950 °C. Moreover, the V-containing Sn-V alloys were initiated to spread on porous graphite at ~650 °C and reached a quasi-equilibrium state at ~900 °C. Spreading kinetics of Sn-3V alloy on porous graphite well fitted in the classic product reaction controlled (PRC) model. However, our microstructural characterization demonstrated that, besides vanadium carbide formation, the adsorption of V element at the wetting three-phase contact line spontaneously contributed to the reactive spreading and infiltrating of Sn-V alloys on porous graphite. Meanwhile, the formation of continuous vanadium carbides could completely block the infiltration of Sn-V active solder alloy in porous graphite. Affected by the growth kinetics of vanadium carbides, the infiltration depth of Sn-V alloys in porous graphite decreased at increased isothermal wetting temperatures. This work is believed to provide implicative notions on the fabrication of graphite related materials and devices using novel V-containing bonding alloys.

Molecular cloning, characterization, and immunolocalization of two lactate dehydrogenase homologous genes from Taenia solium.

Two novel genes encoding lactate dehydrogenase A (LDHA) and B (LDHB) homologues, respectively, were identified from the cDNA libraries of adult Taenia solium (T. solium). The two deduced amino acid sequences both show more than 50% identity to the homologues for Danio rerio, Xenopus laevis, Schistosoma japonicum, Sus scrofa, Homo sapiens, et al. The identity of the amino acid sequence between TsLDHA and TsLDHB is 57.4%, and that of the nucleotide sequence is 61.5%. Recombinant TsLDHA homologue (rTsLDHA) and TsLDHB homologue (rTsLDHB) were expressed in Escherichia coli BL21/DE3 and purified. Though there were some differences in the sequence, the two LDH isozyme homologues show similarity in the conserved LDH domain, topological structure, primary immunological traits, localization on the tegument of T. solium adult, and partial physicochemical properties. The linear B-cell epitope analysis of TsLDHA and TsLDHB discovered a TsLDHA specific epitope. The purified rTsLDHA and rTsLDHB could be recognized by rat immuno-sera, serum from swine, or a patient infected with T. solium, respectively, but Western blot analysis showed cross-reactions, not only between these two LDH members but also with other common human tapeworms or helminths. The results suggested that the two LDH homologues are similar in the characteristics of LDH family, and they are not specific antigens for immunodiagnosis.