To provide theoretical basis and practical guidance for preparing composite rods by direct continuous casting, copper-clad aluminum composite rods of external copper layer diameter 12 mm and inner aluminum core diamet...To provide theoretical basis and practical guidance for preparing composite rods by direct continuous casting, copper-clad aluminum composite rods of external copper layer diameter 12 mm and inner aluminum core diameter 8 mm were manufactured. Orthogonal tests consisted of three factors and three levels were carried out to research the effects of melting copper temperature, continuous casting speed and nitrogen pressure on the performance of composite rods. Results showed that nitrogen pressure is the most important factor in influencing the surface quality; continuous casting speed is the most important factor in influencing copper & aluminum inter diffusion amount. Nitrogen pressure can noticeably improve the surface quality and make the rods easily be drawn out, but the surface quality does not show visible improvement when the nitrogen pressure is above 0.05 MPa. Measured by tests, the compound layer can be divided into three types according to its cladding layer degree: deficient cladding, normal cladding and excess cladding. The diameter of normal copper-clad aluminum composite rods can be successfully drawn less than 0.6 mm without annealing.展开更多
With conventional fertilization as the control,the control effects of biological fertilizer and general organic fertilizer on watermelon Fusarium wilt were studied in the paper. The results showed that applying biolog...With conventional fertilization as the control,the control effects of biological fertilizer and general organic fertilizer on watermelon Fusarium wilt were studied in the paper. The results showed that applying biological fertilizer could effectively reduce the incidence rate of watermelon Fusarium wilt and significantly improve the quality of watermelon,while application of general organic fertilizer had no obvious control effect on watermelon Fusarium wilt.展开更多
Ultrafast optical nonlinearities of N,N-dimethylformamide(DMF)are studied by using polarized light at 400 nm.Both nonlinear refraction(NLR)and stimulated Rayleigh-wing scattering(SRWS)depend on the polarization state ...Ultrafast optical nonlinearities of N,N-dimethylformamide(DMF)are studied by using polarized light at 400 nm.Both nonlinear refraction(NLR)and stimulated Rayleigh-wing scattering(SRWS)depend on the polarization state of incident beam,while two-photon absorption(TPA)changes negligibly with polarization state.The polarization dependence of SRWS originates from that of NLR via self-focusing effect.Third-order susceptibility elements of DMF were determined,and a method to distinguish the multi-photon absorption signal from SRWS in Z-scan is provided.These results are helpful for the nonlinear optical research of the novel materials dissolved in DMF.展开更多
The valence electronic structures of Fe, Co and Ni have been investigated with Empirical Electron Theory of Solids and Molecules. The magnetic moments, Curie temperature, cohesive energy and melting point have been ca...The valence electronic structures of Fe, Co and Ni have been investigated with Empirical Electron Theory of Solids and Molecules. The magnetic moments, Curie temperature, cohesive energy and melting point have been calculated according to the valence electronic structure. These calculations fit the experimental data very well. Based on the calculations, the magnetic moments are proportional to the number of 3d magnetic electrons. Curie temperatures are related to the magnetic electrons and the bond lengths between magnetic atoms. Cohesive energies increase with the increase of the number of covalent electrons, and the decrease of the number of magnetic and dumb pair electrons. The melting point is mainly related to the number of covalent electron pairs distributed in the strongest bond. The contribution from the lattice electrons is very small, the dumb pair electrons weaken the melting point; however, the contribution to melting point of the magnetic electrons can be neglected. It reveals that the magnetic and thermal properties are closely related to the valence electronic structures, and the changes or transitions between the electrons obviously affect the physical properties.展开更多
基金financially supported by the Program for New Century Excellent Talents in University(NCET-12-0849)the Fundamental Research Funds for the Central Universities(13ZD12)the National Natural Science Foundation of China(No.51006034)
文摘To provide theoretical basis and practical guidance for preparing composite rods by direct continuous casting, copper-clad aluminum composite rods of external copper layer diameter 12 mm and inner aluminum core diameter 8 mm were manufactured. Orthogonal tests consisted of three factors and three levels were carried out to research the effects of melting copper temperature, continuous casting speed and nitrogen pressure on the performance of composite rods. Results showed that nitrogen pressure is the most important factor in influencing the surface quality; continuous casting speed is the most important factor in influencing copper & aluminum inter diffusion amount. Nitrogen pressure can noticeably improve the surface quality and make the rods easily be drawn out, but the surface quality does not show visible improvement when the nitrogen pressure is above 0.05 MPa. Measured by tests, the compound layer can be divided into three types according to its cladding layer degree: deficient cladding, normal cladding and excess cladding. The diameter of normal copper-clad aluminum composite rods can be successfully drawn less than 0.6 mm without annealing.
基金Supported by Special Fund for Nonprofit Industry of Ministry of Agriculture(2011R20A24B02)Support Project of Science and Technology Ministry(2012BAC17B02-2-1)+1 种基金Nonprofit Agricultural Research Projects of Zhejiang Province(2010C32016)Provincial Major Science and Technology Projects(priority topics)for Agricultural Program(2008C12045-1)
文摘With conventional fertilization as the control,the control effects of biological fertilizer and general organic fertilizer on watermelon Fusarium wilt were studied in the paper. The results showed that applying biological fertilizer could effectively reduce the incidence rate of watermelon Fusarium wilt and significantly improve the quality of watermelon,while application of general organic fertilizer had no obvious control effect on watermelon Fusarium wilt.
基金the National Natural Science Foundation of China(No.12074202)the Natural Science Foundation of Tianjin City(Nos.22JCYBJC00390 and 20JCQNJC00020)。
文摘Ultrafast optical nonlinearities of N,N-dimethylformamide(DMF)are studied by using polarized light at 400 nm.Both nonlinear refraction(NLR)and stimulated Rayleigh-wing scattering(SRWS)depend on the polarization state of incident beam,while two-photon absorption(TPA)changes negligibly with polarization state.The polarization dependence of SRWS originates from that of NLR via self-focusing effect.Third-order susceptibility elements of DMF were determined,and a method to distinguish the multi-photon absorption signal from SRWS in Z-scan is provided.These results are helpful for the nonlinear optical research of the novel materials dissolved in DMF.
基金Supported by the National High Technology Development Program of China (Grant No.2007AA03Z458)
文摘The valence electronic structures of Fe, Co and Ni have been investigated with Empirical Electron Theory of Solids and Molecules. The magnetic moments, Curie temperature, cohesive energy and melting point have been calculated according to the valence electronic structure. These calculations fit the experimental data very well. Based on the calculations, the magnetic moments are proportional to the number of 3d magnetic electrons. Curie temperatures are related to the magnetic electrons and the bond lengths between magnetic atoms. Cohesive energies increase with the increase of the number of covalent electrons, and the decrease of the number of magnetic and dumb pair electrons. The melting point is mainly related to the number of covalent electron pairs distributed in the strongest bond. The contribution from the lattice electrons is very small, the dumb pair electrons weaken the melting point; however, the contribution to melting point of the magnetic electrons can be neglected. It reveals that the magnetic and thermal properties are closely related to the valence electronic structures, and the changes or transitions between the electrons obviously affect the physical properties.
