G2 G1 Research Articles

Antiplane strain problem of diamond inclusion

In this paper, the singular stress fields created by an antiplane deformation at an inclusion corner are studied. It is shown that these singular stress fields can be separated into two independent types: a symmetric type with the stress singularity of 1/Υ 1−λ1 and a skew-symmetric type with the stress singularity of 1/Υ 1−λ2. These two types of the singular stress field can not occur simultaneously at the corner. If G2 G1, there exists only the singularity of the symmetric type. A general expression of stress fields in the vicinity of the corner is presented. In the expression the singular stress fields for the symmetric type and the skew-symmetric type are defined in terms of the constants KIII, λ1 and KIII, λ2, respectively. KIII, λ2 and KIII, λ2 have to be determined from the complete boundary conditions of the given problem. For the problem of an infinite plate containing a diamond inclusion and subjected to a uniform longitudinal shear stress at infinity, the values of KIII, λ1 and KIII, λ2 are obtained by body force method. In the body force method, the investigated stresses are simulated by the superposition of the fundamental stress fields due to point forces. In order to obtain accurate solutions, the basic density functions of the distributed point forces are used, so that the stress singularities at the corner tip can be simulated by the point forces.

Singular Stress Fields near a Corner of Jointed Dissimilar Materials under Antiplane Loads.

In this paper the characteristics of the stress fields near a corner of jointed dissimilar materials under antiplane loads are studied. It is found that the singular stress fields due to the antiplane loads can be divided into two types: a symmetric type with a stress singularity of 1/γ1-λ1 and a skew-symmetric type with a stress singularity of 1/γ1-λ2. If G2 G1, there exists only the singularity of symmetric type. An expression of stress fields at the close vicinity of the corner is presented. Based on the expression the singular stress fields are defined in terms of two constants KIII, λ1 and KIII, λ2 for the symmetric type and the skew-symmetric type, respectively.

ChemInform Abstract: CRYSTAL STRUCTURE AND ELECTRONIC PROPERTIES OF BIS(2,2′‐BIPYRIDYL)THIOCYANATOCOPPER(II) TETRAFLUOROBORATE

The crystal structure of the title compound, [Cu(bipy)2(NCS)][BF4](1)(bipy = 2,2′-bipyridyl), has been determined by X-ray analysis. It crystallises in the monoclinic space group C2/c with a= 12.791 (3), b= 24.641 (4), c= 15.456(3)A, β= 107.4(1)°, and Z= 8. The five-co-ordinate CuN2N′2N″ chromophore has a distorted bipyramidal stereochemistry related to a regular trigonal-bipyramidal stereochemistry by a distortion towards square pyramidal. The single-crystal e.s.r. spectra involve rhombic g values, R= 1.21 [(g2–g1)/(g3–g2) where g1 < g2 < g3], and cannot be used to distinguish between a dz2 or dx2–y2 ground state, but the direction of the highest g value establishes that it correlates with the elongated Cu–N direction of the square-pyramidal distortion of the CuN2N′2N″ chromophore. This, together with the twin-peaked electronic reflectance spectra (11 170 and 14 120 cm–1), suggests that the structure of (1) is best described as square-pyramidal distorted trigonal bipyramidal.

Crystal structure and electronic properties of bis(2,2′-bipyridyl)-thiocyanatocopper(II) tetrafluoroborate

The crystal structure of the title compound, [Cu(bipy)2(NCS)][BF4](1)(bipy = 2,2′-bipyridyl), has been determined by X-ray analysis. It crystallises in the monoclinic space group C2/c with a= 12.791 (3), b= 24.641 (4), c= 15.456(3)A, β= 107.4(1)°, and Z= 8. The five-co-ordinate CuN2N′2N″ chromophore has a distorted bipyramidal stereochemistry related to a regular trigonal-bipyramidal stereochemistry by a distortion towards square pyramidal. The single-crystal e.s.r. spectra involve rhombic g values, R= 1.21 [(g2–g1)/(g3–g2) where g1 < g2 < g3], and cannot be used to distinguish between a dz2 or dx2–y2 ground state, but the direction of the highest g value establishes that it correlates with the elongated Cu–N direction of the square-pyramidal distortion of the CuN2N′2N″ chromophore. This, together with the twin-peaked electronic reflectance spectra (11 170 and 14 120 cm–1), suggests that the structure of (1) is best described as square-pyramidal distorted trigonal bipyramidal.