Structure and polarity of the Si C single crystal have been analyzed with the four- circle X- ray diffraction method by a double- crystal diffractom eter.The hexagonal{ 10 15 } pole figure shows that this Si C sam pl...Structure and polarity of the Si C single crystal have been analyzed with the four- circle X- ray diffraction method by a double- crystal diffractom eter.The hexagonal{ 10 15 } pole figure shows that this Si C sam ple has a6 H modification.The difference between the integrated intensities m easured byω scan in the triple- axis diffraction set- up finds some convincing evidence that the surface is either a Si- terminated face or C- terminated face.The experi- mental ratios of| F( 0 0 0 L) | 2 / | F( 0 0 0 L) | 2 are in good agreem entwith the calculated ones after the dispersion cor- rections to the atomic scattering factors( L=6 ,12 and18,respectively) .Thus,this m easurem ent technique is con- venient for the application of the materials with remarkable surface polarity.展开更多
X-ray diffraction (XRD) was used to study the structure of the organic crystallite unit (La, Lo doo2) in coals collected from Henan and Shanxi Provinces. XRD patterns of coal were collected in a step-scan mode (0...X-ray diffraction (XRD) was used to study the structure of the organic crystallite unit (La, Lo doo2) in coals collected from Henan and Shanxi Provinces. XRD patterns of coal were collected in a step-scan mode (0.1 °/step) over an angular range of 2-90° (20), allowing 8 s at each step. The structure of the crystallite unit was determined from the Scherrer equation and peak parameters deduced from whole pattern fitting. The results show that the structure of the crystallite unit in coal is mainly controlled by the coal rank. As the coal rank increases the average diameter of a coal crystallite unit (La) increases, the interlayer spacing (doo2) decreases slightly, and the average height of a coal crystallite unit (Lc) increases at first but then decreases. A new diffraction peak from the crystallite unit in coal was found at a low scattering angle in the XRD pattern (2-10~). This suggests a structure with an inter-layer spacing from 1.9 to 2.8 nm exists in coal crystallites.展开更多
New heteroleptic and homoleptic complexes of the type[Pd(4,5-dmbipy)C12], [Pd(4,5-dmbipy)L2], and [Pd(4,5-dimebipy)2]2+ (L = Pyridine or 4-methylpyridine(4-picoline), bipy = 2,2'-bipyridine, and 4,5-dimebip...New heteroleptic and homoleptic complexes of the type[Pd(4,5-dmbipy)C12], [Pd(4,5-dmbipy)L2], and [Pd(4,5-dimebipy)2]2+ (L = Pyridine or 4-methylpyridine(4-picoline), bipy = 2,2'-bipyridine, and 4,5-dimebipy = 4,5-dimethyl-2,2'-bipyridine) were synthesized and characterized by IH NMR and elemental analysis. The crystal structure of bis(4-methylpyridine)-4,5- dimethyl-2,2'-bipyridinepalladium(II)perchlorate [Pd(4,5-dmbipy)(4-pic)2](CIO4)2 was also determined by single crystal X-ray diffraction. This complex crystallized in the triclinic crystal system and space group PI with a = 9.562 (2), b = 11.326 (4), c = 15.0120 (10) A°; α = 70.940°, β= 77.60 (2), γ= 67.86 (2) and z = 4. The Pd (II) in square planar environment showed a small distortion towards tetrahedral through one coordinated bipyridine ring twisting with respect to the other.展开更多
With further increase of the number of on-chip device, the bus structure has not met the requirements. In order to make better communication between each part, the chip designers need to explore a new structure to sol...With further increase of the number of on-chip device, the bus structure has not met the requirements. In order to make better communication between each part, the chip designers need to explore a new structure to solve the interconnection of on-chip device. The paper proposes a network-on-chip dynamic and adaptive algorithm which selects NoC platform with 2-dimension mesh as the carrier, incorporates communication energy consumption and delay into unified cost function and uses ant colony optimization to realize NOC map facing energy consumption and delay. The experiment indicates that compared with random map, single objective optimization can separately saves (30% - 47 %) and ( 20% - 39%) in communication energy consumption and execution time compared with random map, and joint objective optimization can further excavate the potential of time dimension in mapping scheme dominated by the energy.展开更多
Single crystalline CdTe nanowires have been synthesized using Au-catalyzed chemical vapor deposition. X-ray diffraction reveals the existence of non- negligible inhomogeneous compressive strain in the nanowires along ...Single crystalline CdTe nanowires have been synthesized using Au-catalyzed chemical vapor deposition. X-ray diffraction reveals the existence of non- negligible inhomogeneous compressive strain in the nanowires along the 〈111〉 growth direction. The effect of the strain on the electronic structure is manifested by the blue-shifted and broadened photoluminescence spectra involving shallow donor/acceptor states. Such residual strain is of great importance for a better understanding of the optical and electrical behaviors of various semiconductor nanomaterials as well as for device design and applications.展开更多
Two new different Cu(Ⅱ) MOFs with the same 1,3,5-tris(1-imidazolyl) benzene(tib) ligand {[Cu(tib)2]·(H2O)2·Br2}n(1) and {[Cu2(tib)·Br·Cl]·2Br}n(2) were obtained by one pot synthesized of tib ...Two new different Cu(Ⅱ) MOFs with the same 1,3,5-tris(1-imidazolyl) benzene(tib) ligand {[Cu(tib)2]·(H2O)2·Br2}n(1) and {[Cu2(tib)·Br·Cl]·2Br}n(2) were obtained by one pot synthesized of tib with CuBr in the presences of HCl and water. X-ray single crystal diffraction analyses indicate that both complexes 1 and 2 have two dimensional frameworks containing different building blocks. Each Cu(Ⅱ) atom in complex 1 is coordinated by four N atoms from different tib ligands. However, there are two different cryptographic Cu(Ⅱ) atoms in complex 2, one is four coordinated by two bromine atoms and two N atoms from different tib ligands, the other is six coordinated by two chloride atoms and four N atoms from different tib ligands. The thermal gravimetric analysis of complexes 1 and 2 are depicted in the paper.展开更多
Employing unsymmetrical 2-mercapto-5-methyl-1,3,4-thiadiazole and 2,2′-bipyridine as mixed ligands, a new low-dimensional coordination polymer [Zn(MMTA) 2 (2,2′-bipy)] n (MMTA = 2-mercapto-5-methyl-1,3,4-thiadiazole...Employing unsymmetrical 2-mercapto-5-methyl-1,3,4-thiadiazole and 2,2′-bipyridine as mixed ligands, a new low-dimensional coordination polymer [Zn(MMTA) 2 (2,2′-bipy)] n (MMTA = 2-mercapto-5-methyl-1,3,4-thiadiazole, 2,2′-bipy = 2,2′-bipyridine), has been synthesized under solvothermal condition and characterized by single crystal X-ray diffraction. This compound crys- tallizes in the noncentrosymmetric space group Cc, with cell parameters: a = 8.291(4) , b = 15.483(9) , c = 15.620(6) , = 96.00(5)°, V = 1994.1(2) 3 , and Z = 4. The mixed ligands link the zinc center into a mononuclear unit, which is futher linked by weak C-H···N and C-H···S hydrogen bonds into a three-dimensional noncentrosymmetric framework. The compound exhibits intense photoluminescence and distinct NLO properties at room temperature. The intensity of the green light produced by the powder sample of the compound is about 3.2 times that produced by KDP powder. On the basis of the results of TG analysis, the structure is thermally stable up to ~260 °C.展开更多
By means of electron backscattering diffraction and transmission electron microscopy the microstructure and texture of drawn single crystal copper with initial orientation (110) parallel to axial direction have been...By means of electron backscattering diffraction and transmission electron microscopy the microstructure and texture of drawn single crystal copper with initial orientation (110) parallel to axial direction have been investigated in the present work. In or- der to analyze the effect of initial orientation on microstructure and texture of drawn copper, the results of the drawn (110) sin- gle crystal copper wires have been compared with (100) and (111) single crystal copper wires. It is found that the grain subdi- vision of (110) single crystal is more evident than that of (100) and (111), and the textures consisting of (111) and (100) abruptly form in the drawn (110) single crystal. At high strains, due to shear strain, the distribution of fiber textures is imho- mogenous along the radial direction of drawn (110) single crystal copper wires. (100) is near the surface and (111) is at the center. The microstructure results of drawn (110) single crystal show that at low strains, it can be characterized as two kinds of geometrically necessary boundaries with noncrystalline character. At medium strains, S bands can be observed. At high strains, lamellar boundaries form. Mean misofientation and average spacing of dislocation boundary are larger in drawn (110) single crystal, as compared with (111) and (100). In drawn (110) single crystal with high strains, the bimodal distribution forms at lower strains than in drawn (100) single crystal, which is because the dislocation boundaries with high angle are contributed by not only the boundary between (111) and (100) fiber textures but also the boundary in (111) or (100) texture.展开更多
In this study, we reported the design, fabrication, and characterization of well- ordered arrays of vertically-aligned, epitaxial NiSi2/Si heterostructures and single- crystalline NiSi2 nanowires on (001)Si substrat...In this study, we reported the design, fabrication, and characterization of well- ordered arrays of vertically-aligned, epitaxial NiSi2/Si heterostructures and single- crystalline NiSi2 nanowires on (001)Si substrates. The epitaxial NiSi2 with {111} facets was found to be the first and the only silicide phase formed inside the Si nanowires after annealing at a temperature as low as 300℃. Upon annealing at 500 ℃ for 4 h, the residual parts of Si nanowires were completely consumed and the NiSi2/Si heterostructured nanowires were transformed to fully silicided NiSi2 nanowires. XRD, TEM and SAED analyses indicated that all the NiSi2 nanowires were single crystalline and their axial orientations were parallel to the [001] direction. The obtained vertically-aligned NiSi2 nanowires, owing to their well-ordered arrangement, single-crystalline structure, and low effective work function, exhibit excellent field-emission properties with a very low turn-on field of 1.1 V/m. The surface wettability of the nanowires was found to switch from hydrophobic to hydrophilic after the formation of NiSi2 phase and the measured water contact angle decreased with increasing extent of Ni silicidation. The increased hydrophilicity can be explained by the Wenzel model. The obtained results present the exciting prospect that the new approach proposed here will provide the capability to fabricate other highly-ordered, vertically-aligned fully silicided nanowire arrays and may offer potential applications in constructing vertical silicide-based nanodevices.展开更多
文摘Structure and polarity of the Si C single crystal have been analyzed with the four- circle X- ray diffraction method by a double- crystal diffractom eter.The hexagonal{ 10 15 } pole figure shows that this Si C sam ple has a6 H modification.The difference between the integrated intensities m easured byω scan in the triple- axis diffraction set- up finds some convincing evidence that the surface is either a Si- terminated face or C- terminated face.The experi- mental ratios of| F( 0 0 0 L) | 2 / | F( 0 0 0 L) | 2 are in good agreem entwith the calculated ones after the dispersion cor- rections to the atomic scattering factors( L=6 ,12 and18,respectively) .Thus,this m easurem ent technique is con- venient for the application of the materials with remarkable surface polarity.
基金supported in part by Program for New Century Excellent Talents in University of China (No. NCET-10-0133)Innovation Scientists and Technicians Troop Construction Projects of Henan Province (No. 114100510004)
文摘X-ray diffraction (XRD) was used to study the structure of the organic crystallite unit (La, Lo doo2) in coals collected from Henan and Shanxi Provinces. XRD patterns of coal were collected in a step-scan mode (0.1 °/step) over an angular range of 2-90° (20), allowing 8 s at each step. The structure of the crystallite unit was determined from the Scherrer equation and peak parameters deduced from whole pattern fitting. The results show that the structure of the crystallite unit in coal is mainly controlled by the coal rank. As the coal rank increases the average diameter of a coal crystallite unit (La) increases, the interlayer spacing (doo2) decreases slightly, and the average height of a coal crystallite unit (Lc) increases at first but then decreases. A new diffraction peak from the crystallite unit in coal was found at a low scattering angle in the XRD pattern (2-10~). This suggests a structure with an inter-layer spacing from 1.9 to 2.8 nm exists in coal crystallites.
文摘New heteroleptic and homoleptic complexes of the type[Pd(4,5-dmbipy)C12], [Pd(4,5-dmbipy)L2], and [Pd(4,5-dimebipy)2]2+ (L = Pyridine or 4-methylpyridine(4-picoline), bipy = 2,2'-bipyridine, and 4,5-dimebipy = 4,5-dimethyl-2,2'-bipyridine) were synthesized and characterized by IH NMR and elemental analysis. The crystal structure of bis(4-methylpyridine)-4,5- dimethyl-2,2'-bipyridinepalladium(II)perchlorate [Pd(4,5-dmbipy)(4-pic)2](CIO4)2 was also determined by single crystal X-ray diffraction. This complex crystallized in the triclinic crystal system and space group PI with a = 9.562 (2), b = 11.326 (4), c = 15.0120 (10) A°; α = 70.940°, β= 77.60 (2), γ= 67.86 (2) and z = 4. The Pd (II) in square planar environment showed a small distortion towards tetrahedral through one coordinated bipyridine ring twisting with respect to the other.
文摘With further increase of the number of on-chip device, the bus structure has not met the requirements. In order to make better communication between each part, the chip designers need to explore a new structure to solve the interconnection of on-chip device. The paper proposes a network-on-chip dynamic and adaptive algorithm which selects NoC platform with 2-dimension mesh as the carrier, incorporates communication energy consumption and delay into unified cost function and uses ant colony optimization to realize NOC map facing energy consumption and delay. The experiment indicates that compared with random map, single objective optimization can separately saves (30% - 47 %) and ( 20% - 39%) in communication energy consumption and execution time compared with random map, and joint objective optimization can further excavate the potential of time dimension in mapping scheme dominated by the energy.
文摘Single crystalline CdTe nanowires have been synthesized using Au-catalyzed chemical vapor deposition. X-ray diffraction reveals the existence of non- negligible inhomogeneous compressive strain in the nanowires along the 〈111〉 growth direction. The effect of the strain on the electronic structure is manifested by the blue-shifted and broadened photoluminescence spectra involving shallow donor/acceptor states. Such residual strain is of great importance for a better understanding of the optical and electrical behaviors of various semiconductor nanomaterials as well as for device design and applications.
基金funded by the National Natural Science Foundation of China(21261009)Young Scientist Foundation of Jiangxi Provincethe Education Fund of Jiangxi Province(GJJ13434)
文摘Two new different Cu(Ⅱ) MOFs with the same 1,3,5-tris(1-imidazolyl) benzene(tib) ligand {[Cu(tib)2]·(H2O)2·Br2}n(1) and {[Cu2(tib)·Br·Cl]·2Br}n(2) were obtained by one pot synthesized of tib with CuBr in the presences of HCl and water. X-ray single crystal diffraction analyses indicate that both complexes 1 and 2 have two dimensional frameworks containing different building blocks. Each Cu(Ⅱ) atom in complex 1 is coordinated by four N atoms from different tib ligands. However, there are two different cryptographic Cu(Ⅱ) atoms in complex 2, one is four coordinated by two bromine atoms and two N atoms from different tib ligands, the other is six coordinated by two chloride atoms and four N atoms from different tib ligands. The thermal gravimetric analysis of complexes 1 and 2 are depicted in the paper.
基金supported by the National Natural Science Foundation of China (20701023 & 51102138)the Natural Science Foundation of Shandong Province, China (BS2010NJ004 &2009ZRB019KH)
文摘Employing unsymmetrical 2-mercapto-5-methyl-1,3,4-thiadiazole and 2,2′-bipyridine as mixed ligands, a new low-dimensional coordination polymer [Zn(MMTA) 2 (2,2′-bipy)] n (MMTA = 2-mercapto-5-methyl-1,3,4-thiadiazole, 2,2′-bipy = 2,2′-bipyridine), has been synthesized under solvothermal condition and characterized by single crystal X-ray diffraction. This compound crys- tallizes in the noncentrosymmetric space group Cc, with cell parameters: a = 8.291(4) , b = 15.483(9) , c = 15.620(6) , = 96.00(5)°, V = 1994.1(2) 3 , and Z = 4. The mixed ligands link the zinc center into a mononuclear unit, which is futher linked by weak C-H···N and C-H···S hydrogen bonds into a three-dimensional noncentrosymmetric framework. The compound exhibits intense photoluminescence and distinct NLO properties at room temperature. The intensity of the green light produced by the powder sample of the compound is about 3.2 times that produced by KDP powder. On the basis of the results of TG analysis, the structure is thermally stable up to ~260 °C.
基金supported by the National Natural Science Foundation of China (Grant Nos. 50901055, 50771076)the Education Department Foundation of Shanxi Province, China (Grant No. 07JK274)
文摘By means of electron backscattering diffraction and transmission electron microscopy the microstructure and texture of drawn single crystal copper with initial orientation (110) parallel to axial direction have been investigated in the present work. In or- der to analyze the effect of initial orientation on microstructure and texture of drawn copper, the results of the drawn (110) sin- gle crystal copper wires have been compared with (100) and (111) single crystal copper wires. It is found that the grain subdi- vision of (110) single crystal is more evident than that of (100) and (111), and the textures consisting of (111) and (100) abruptly form in the drawn (110) single crystal. At high strains, due to shear strain, the distribution of fiber textures is imho- mogenous along the radial direction of drawn (110) single crystal copper wires. (100) is near the surface and (111) is at the center. The microstructure results of drawn (110) single crystal show that at low strains, it can be characterized as two kinds of geometrically necessary boundaries with noncrystalline character. At medium strains, S bands can be observed. At high strains, lamellar boundaries form. Mean misofientation and average spacing of dislocation boundary are larger in drawn (110) single crystal, as compared with (111) and (100). In drawn (110) single crystal with high strains, the bimodal distribution forms at lower strains than in drawn (100) single crystal, which is because the dislocation boundaries with high angle are contributed by not only the boundary between (111) and (100) fiber textures but also the boundary in (111) or (100) texture.
文摘In this study, we reported the design, fabrication, and characterization of well- ordered arrays of vertically-aligned, epitaxial NiSi2/Si heterostructures and single- crystalline NiSi2 nanowires on (001)Si substrates. The epitaxial NiSi2 with {111} facets was found to be the first and the only silicide phase formed inside the Si nanowires after annealing at a temperature as low as 300℃. Upon annealing at 500 ℃ for 4 h, the residual parts of Si nanowires were completely consumed and the NiSi2/Si heterostructured nanowires were transformed to fully silicided NiSi2 nanowires. XRD, TEM and SAED analyses indicated that all the NiSi2 nanowires were single crystalline and their axial orientations were parallel to the [001] direction. The obtained vertically-aligned NiSi2 nanowires, owing to their well-ordered arrangement, single-crystalline structure, and low effective work function, exhibit excellent field-emission properties with a very low turn-on field of 1.1 V/m. The surface wettability of the nanowires was found to switch from hydrophobic to hydrophilic after the formation of NiSi2 phase and the measured water contact angle decreased with increasing extent of Ni silicidation. The increased hydrophilicity can be explained by the Wenzel model. The obtained results present the exciting prospect that the new approach proposed here will provide the capability to fabricate other highly-ordered, vertically-aligned fully silicided nanowire arrays and may offer potential applications in constructing vertical silicide-based nanodevices.