Study on the Structural Characteristics and Physical and Mechanical Properties of Phoebe bournei Thinning Wood

The artificial afforestation of precious Phoebe bournei has been carried out in China.During the cultivation process,thinning wood will be produced.The properties of thinning wood might vary greatly with matured wood and require evaluation for better utilization.The objective of the present study aims to determine the wood structure,fiber morphology,and physical and mechanical properties of the Phoebe bournei thinning wood to help us understand the wood properties and improve its utility value.Three 14-year-old Phoebe bournei were cut from Jindong Forestry Farm of Hunan Province,China.The wood structure and fiber morphology were observed and analyzed with a light microscope and scanning electron microscope.The physical and mechanical properties were tested according to the Chinese national standards.The results showed as follows:(1)The Phoebe bournei thinning wood has a beautiful wood figure and fine texture,whereas the heartwood has not yet formed.(2)It is a diffuse-porous hardwood with small and less pores as well as fine wood rays.(3)The wood fiber is medium length and extremely thin wall thickness.(4)It is low in density and has excellent dimensionally stability.(5)The wood mechanical properties belong to the low to medium class and the comprehensive strength of wood belongs to the medium-strength class.It is concluded that Phoebe bournei thinning wood is suitable for wood carving,handicraft,high-end furniture,and decorative furniture parts.

A pattern for the flavor dependent quark-antiquark interaction

A flavor dependent kernel is constructed based on the rainbow-ladder truncation of the Dyson-Schwinger and Bethe-Salpeter equations in quantum chromodynamics.The quark-antiquark interaction is composed of a flavor dependent infrared part and a flavor independent ultraviolet part.Our model gives a successful and unified description of the light,heavy and heavy-light ground state pseudoscalar and vector mesons.Our model shows,for the first time,that the infrared enhanced quark-antiquark interaction is stronger and wider for lighter quarks.

Quantum numbers of the pentaquark states Pc+ via symmetry analysis

We investigate the quantum numbers of the pentaquark states Pc+,which are composed of 4(three flavors)quarks and an antiquark,by analyzing their inherent nodal structure in this paper.Assuming that the four quarks form a tetrahedron or a square,and the antiquark is at the ground state,we determine the nodeless structure of the states with orbital angular moment L≤3,and in turn,the accessible low-lying states.Since the inherent nodal structure depends only on the inherent geometric symmetry,we propose the quantum numbers JPof the low-lying pentaquark states P_c^+may be■,■,■and■,independent of dynamical models.

Radial excited heavy mesons

In this study,the first radial excited heavy pseudoscalar and vector mesons(η_(c)(2S),ψ(2S),B_(c)(2S),B_(c)^(*)(2S),η_(b)(2S),and γ(2S))are investigated using the Dyson-Schwinger equation and Bethe-Salpeter equation approach.It is shown that the effective interactions of the radial excited states are harder than those of the ground states.With the interaction well determined by fitting the masses and leptonic decay constants of ψ(2S)and γ(25),the first radial excited heavy mesons could be quantitatively described in the rainbow ladder approximation.The masses and leptonic decay constants of η_(c)(2S),ψ(2S),B_(c)(2S),B_(c)^(*)(2S),and η_(b)(2S) are predicted.