Chen, Lin
Li, Longna
Yang, Guodong
Qian, Huirong
Li, Mingzhi
Tsuga longibracteata W. C. Cheng is an endangered coniferous species endemic to China. Here, the complete chloroplast genome of this species was assembled and characterized from high-throughput sequencing data. The circular genome of T. longibracteata was 120,900bp in size, with a pair of inverted repeat regions of 34,239bp. The chloroplast genome contains 127 genes including 88 protein-coding genes (PCGs), 34 tRNAs and five rRNAs. Most of genes occurred in a single copy, while 29 PCGs, 11 tRNAs and one rRNA are totally duplicated. The overall AT content of the genome is 60.6%. A phylogenetic tree reconstructed by 20 gymnosperm chloroplast genomes reveals all the species of Pinaceae formed a monophyletic clade with high resolution value and T. longibracteata is most related with T. chinensis. This study will pave the way for future research to understand the genomic information and conservation of this endangered endemic relict plant.
In mortar and concrete, the microstructure of the cement paste is affected by the presence of the aggregate and sand particles and this is most significant in the interfacial transition zone (ITZ). The durability of concrete is affected by the inferior proportion of constituents in ITZ compared with bulk paste, i.e. higher porosity, higher calcium hydroxide (CH), lower calcium silicate hydroxide (C-S-H), and almost no anhydrous in ITZ. This work for the first time investigates the effect of sand size on the proportion of different constituents in ITZ and mortar as a whole. It shows that, as sand size reduces, the shearing force exerted on the paste during mixing increases leading to an increase in C-S-H/CH ratio. Also the effective w/c ratios in the ITZs are calculated for different sand sizes. It is shown that water/cement (w/c) ratio increases with sand size and decreases with distance from the sand surface.
Kim, Jae-Hee
Park, Choongkwon
Ha, Daegwon
Kang, Shinhoo
Abstract Precipitates were induced by aging super-saturated (Zr,W)C solid solution carbides. The temperature dependence of their solubility was analyzed, as were their mechanical properties (hardness and toughness). The solubility limit of WC in the (Zr,W)C was 0.15 ± 0.03 mol fraction at 1500 °C and 0.27 ± 0.03 mol fraction at 1850 °C. The aged (Zr0.7W0.3)C ceramics were significantly strengthened up to 8 MPa m1/2 compared with the as-sintered (Zr0.7W0.3)C.
Khorsand, S.
Karbasi, M.
Sayyedan, F. S.
Eshaghian, M.
Razavi, M.
The parameters for the electroplating process of Ni-Fe(Ti,W)C nanocomposite on the steel substrate were developed and optimised. for this purpose, the coating process was performed under a direct current using a nickel bath. The coating was fully characterised employing the X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy and microhardness tester. The results indicated that the Ni-Fe(Ti,W)C nanocomposite can be coated on the steel with an appropriate structure using the current density and the concentration of 40 mA cm(-2) and 6 g L-1, respectively.
Partially solutionized carbide cermets (PSCs) were prepared for cutting tool applications by replacing a portion of Ti(CN) with (Ti0.88W0.12) C or (Ti0.88W0.12)(C0.7N0.3) in a conventional Ti(CN)-based cermet. The PSC containing (Ti0.88W0.12) C exhibited high fracture toughness with no loss of hardness. The elimination of Ti(C0.7N0.3) cores in the microstructure reduced the strain at the core/rim interfaces, leading to the increase in fracture toughness. The PSC containing (Ti0.88W0.12) C showed coherent relationships at the core/rim and rim/binder interfaces, contributing to the improved mechanical properties. In contrast, nitrogen in (Ti0.88W0.12)(C0.7N0.3) resulted in a different microstructure and properties. The major factors determining the mechanical properties of the cermets are discussed in terms of the carbide/binder interfaces and the thermal stability of the added carbides. (C) 2015 Elsevier B.V. All rights reserved.
Highlights • The addition of (Ti0.88W0.12)C significantly improved the toughness of cermets. • The ceramic particles in the cermets exhibited {111} plane faceting. • The coherency state at the core/rim/binder interfaces led to high toughness. • The thermal stability of constituents and nitrogen in the system are the main causes. Abstract Partially solutionized carbide cermets (PSCs) were prepared for cutting tool applications by replacing a portion of Ti(CN) with (Ti0.88W0.12)C or (Ti0.88W0.12)(C0.7N0.3) in a conventional Ti(CN)-based cermet. The PSC containing (Ti0.88W0.12)C exhibited high fracture toughness with no loss of hardness. The elimination of Ti(C0.7N0.3) cores in the microstructure reduced the strain at the core/rim interfaces, leading to the increase in fracture toughness. The PSC containing (Ti0.88W0.12)C showed coherent relationships at the core/rim and rim/binder interfaces, contributing to the improved mechanical properties. In contrast, nitrogen in (Ti0.88W0.12)(C0.7N0.3) resulted in a different microstructure and properties. The major factors determining the mechanical properties of the cermets are discussed in terms of the carbide/binder interfaces and the thermal stability of the added carbides. Graphical abstract
New relations for the Appell function F-4(a, b; c, c'; w, z) are obtained including differentiation and integration formulas, finite and infinite series, and functional relations. Some reduction and transformation formulas are also presented.