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971.
Hongbo Xia Caiwang Tan Liqun Li Ninshu Ma 《Journal of Materials Engineering and Performance》2018,27(3):1047-1057
Laser welding–brazing of 6061-T6 aluminum alloy to DP590 dual-phase steel with Al-Si12 flux-cored filler wire was performed. The microstructure at the brazing interface was characterized. Fracture behavior was observed and analyzed by in situ scanning electron microscope. The microstructure of the brazing interface showed that inhomogeneous intermetallic compounds formed along the thickness direction, which had a great influence on the crack initiation and propagation. In the top region, the reaction layer at the interface consisted of scattered needle-like Fe(Al,Si)3 and serration-shaped Fe1.8Al7.2Si. In the middle region, the compound at the interface was only serration-shaped Fe1.8Al7.2Si. In the bottom region, the interface was composed of lamellar-shaped Fe1.8Al7.2Si. The cracks were first detected in the bottom region and propagated from bottom to top along the interface. At the bottom region, the crack initiated and propagated along the Fe1.8Al7.2Si/weld seam interface during the in situ tensile test. When the crack propagated into the middle region, a deflection of crack propagation appeared. The crack first propagated along the steel/Fe1.8Al7.2Si interface and then moved along the weld seam until the failure of the joint. The tensile strength of the joint was 146.5 MPa. Some micro-cracks were detected at Fe(Al,Si)3 and the interface between the steel substrate and Fe(Al,Si)3 in the top region while the interface was still connected. 相似文献
972.
De-rui Tan 《中国铸造》2018,(2)
正Western Han Dynasty(206 BC–8 AD)Diameter:12.1 cm;weight:280 g High-tin bronze This marvelous artifact is a cast metal circular disc with interesting relief patterns on the back.When sunlight falls on the surface of the mirror,made 2,000 years ago,the reflected image on a wall shows the pattern on the back of the mirror. 相似文献
973.
De-rui Tan 《中国铸造》2018,(5)
正Five Dynasties and Ten Kingdoms Period (963 A.D. and 967 A.D.)The western tower was damaged and is now incomplete. The eastern tower is 7.7 m high.There are two towers, called the eastern tower and the western tower, which were built in 963 A.D. and 967 A.D.,respectively, and are the earliest extant iron towers. There are 1,024 Buddha statues cast on each side of the tower body.The whole tower is made up of 17 castings, which are stacked layer by layer, and each casting is made to be a single 相似文献
974.
975.
K.L. Nyam C.P. Tan O.M. Lai K. Long Y.B. Che Man 《Food and Bioproducts Processing》2010,88(2-3):239-246
Recovery of phytosterol from roselle (Hibiscus sabdariffa L.) seeds via supercritical carbon dioxide extraction modified with ethanol was investigated at pressures of 200–400 bar, temperatures from 40 to 80 °C and at supercritical fluid flow rates from 10 to 20 ml/min. It was found that an entrainer such as ethanol could enhance the solubility and extraction yield of roselle seed oil from the seed matrix, compared to values obtained using supercritical CO2. After a typical run (holding period of 30 min, continuous flow extraction of 3 h), the results indicate that the oil recovery was optimal with a recovery of 108.74% and a phytosterol composition of 7262.80 mg kg?1 at relatively low temperature of 40 °C, a high pressure of 400 bar and at a high supercritical fluid flow rate of 20 ml/min in the presence of 2 ml/min EtOH as entrainer. The solubility of roselle seed oil increased with temperature at the operating pressures of 200, 300 and 400 bar. Supercritical fluid extraction involved a short extraction time and the minimal usage of small amounts of entrainer in the CO2. 相似文献
976.
P.G. Jayathilake Zhijun Tan B.C. Khoo N.E. Wijeysundera 《Chemical engineering science》2010,65(3):1237-1252
Although permeable and deformable capsules are found in many applications in biological and industrial systems, studies on computational modeling of these capsules are still rather lacking. In this work, the osmotic swelling of a deforming capsule immersed in a diluted binary solution of a non-electrolyte solute under Stokes flows is simulated using the immersed interface method (IIM). The approximate jump conditions for solute concentration are calculated with the use of the Kedem–Katchalsky relations. The capsule membrane is considered to be either semi-permeable or fully permeable, and the material of capsule membrane is assumed to be Neo-Hookean. The employed properties of fluid and membrane lie in the range of a typical biological system. The numerical validation tests indicate that the present calculation procedure has achieved good accuracy in modeling the swelling and deformation of permeable capsules. The capsule swelling (with mass transfer across the membrane) and deformation are tested for different solute concentration fields and membrane permeability properties. Our numerical investigations show that the initial solute concentration field and the membrane permeability properties have much influence on the swelling/deformation of a permeable capsule under Stokes flows. 相似文献
977.
We have achieved in-situ Si incorporation into cubic boron nitride (c-BN) thin films during ion beam assisted deposition. The effects of silicon incorporation on the composition, structure and electric conductivity of c-BN thin films were investigated by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and electrical measurements. The results suggest that the content of the cubic phase remains stable on the whole with the incorporation of Si up to a concentration of 3.3 at.%, and the higher Si concentrations lead to a gradual change from c-BN to hexagonal boron nitride. It is found that the introduced Si atoms only replace B atoms and combine with N atoms to form Si–N bonds, and no evidence of the existence of Si–B bonds is observed. The resistance of the Si-doped c-BN films gradually decreases with increasing Si concentration, and the resistivity of the c-BN film with 3.3 at.% Si is lowered by two orders of magnitude as compared to undoped samples. 相似文献
978.
Xing-wu Tan Bai-mu Wang Ye Wang Shu-zhong Zhan 《Inorganic chemistry communications》2010,13(9):1061-1063
The Mannich reaction of 2-aminoethanol, 2-tert-butyl-4-methylphenol, and formaldehyde at the ratio sets of 1:2:2 provided a new ligand, N-(1-ethanol)-N,N-bis(3-tert-butyl-5-methyl-2-hydroxybenxyl)amine (H3L). In the presence of base, H3L reacted with FeCl3·6H2O to form a dinuclear Fe(III) complex [Fe2L2] 1. The value of μeff at room temperature (5.95 μB), is much less than the expected spin-only value (8.37 μB) of two high spin (hs) Fe3+ (S = 5/2) ions [μ = g[∑ ZS(S + 1)]1/2], indicating there were strong interactions between Fe3+ ions. The effective magnetic moment (μeff) decreased abruptly with cooling to a minimum value of 0.1 μB at 2 K. It was worth noting that Fe3+ ions of 1 exhibited thermally induced quartet ? doublet spin transitions, and these transitions were abrupt. The magnetic behaviors of 1 denoted the occurrence of intramolecular anti-ferromagnetic interactions. J (? 13.58 cm? 1) agrees with the result from Gorun–Lippard equation, ? J (cm? 1) = Aexp(BP(Å) = 12.9). 相似文献
979.
980.
考察了CPAM分散聚合中,两种不同硫酸盐作为分散介质的可行性,并详细讨论了不同类型的分散剂对盐水介质中CPAM分散聚合的影响。通过研究发现,由于硫酸钠在水中的溶解度随温度波动较大,不适合作为CPAM分散聚合的分散介质。另外实验表明,由于非离子型分散剂在盐水介质中溶解性不佳,不适合作为CPAM分散聚合的分散剂。故选择硫酸铵与PDMDAAC分别作为盐水介质中CPAM分散聚合的分散介质与分散剂,并确定了硫酸铵最佳用量为聚合体系质量的27%~29%,PDMDAAC最佳用量为单体质量的10%~18%,该条件下制得的产品具有较好的流动性。 相似文献