H11Mn2SiA焊接用钢连续冷却组织转变与工艺控制

利用Gleeble-1500热模拟试验机测定了H11Mn2SiA的动态连续冷却转变(CCT)曲线,并观察了其组织和硬度。结果表明,当H11Mn2SiA从奥氏体以不同冷却速率冷却时,存在奥氏体向铁素体和珠光体的转变、贝氏体转变和马氏体转变;贝氏体转变的临界冷却速度为2.5℃/s;冷却速度达到20℃/s时会出现马氏体组织;因此H11Mn2SiA的冷却速度应控制在≤1℃/s。实践中选用终轧温度860℃～900℃、吐丝温度850±10℃和0.10～0.15 m/s的辊道速度,能够将冷却速度控制在0.3～0.6℃/s范围内,使H11Mn2SiA获得最佳的组织和性能。     

烧结过程用兰炭作为燃料替代焦粉的生产试验

为降低烧结矿成本,永通公司烧结车间进行了用兰炭做为燃料替代部分焦粉的生产试验,试验结果表明,兰炭替代30％的焦粉时对烧结过程的影响不大,通过采取控制燃料粒度、提高料层厚度、提高点火温度、兰炭焦粉分别配加等措施,完全能满足炼铁对烧结矿产质量的要求,达到降本增效的目的。     

30Cr2Ni4MoVE扣槽转子的生产试制

30Cr2Ni4MoVE扣槽转子,形状复杂,调质性能和防止调质产生变形成为试制的难点。     

Luminescent and photocatalytic properties of hollow SnO2 nanospheres

Size tunable solid SnO₂ (STO) and hollow SnO₂ (HTO) nanospheres were prepared by a sacrificing template method. The peaks around 390 nm were observed in photoluminescence (PL) spectra. Based on the results, the PL intensity exhibits morphology-dependence and size-dependence, and HTO structure displays better optical properties than STO structure. The degradation of Methyl Orange (MO) in aqueous solution is selected as a probe reaction to evaluate the catalytic activity of nano-SnO₂. The result shows that HTO structure presents stronger photocatalytic (PC) activity. According to the result of specific surface area testing, the improved PL and PC properties of HTO structure can be mainly explained by the surface effect induced by large specific surface area. This work is meaningful for developing nanomaterials with enhanced optical and photochemical properties.     

Photocatalytic degradation of an azo dye using Bi3.25M0.75Ti3O12 nanowires (M = La,Sm, Nd,and Eu)

Bi_3.25M_0.75Ti₃O₁₂ (BMT, M = La, Sm, Nd, and Eu) nanowires were synthesized through simple hydrothermal route and their structural and photocatalytic properties were investigated. XRD results indicated that these compounds are of layered perovskites structure. In addition, the band gaps of Bi_3.25La_0.75Ti₃O₁₂ (BLT), Bi_3.25Sm_0.75Ti₃O₁₂ (BST), Bi_3.25Nd_0.75Ti₃O₁₂ (BNT), and Bi_3.25Eu_0.75Ti₃O₁₂ (BET) were estimated to be about 2.403, 2.594, 2.525, and 2.335 eV, respectively. Their photocatalytic activities were evaluated by photocatalytic degradation of methyl orange (MO) under visible light irradiation (λ > 420 nm). Bi_3.25M_0.75Ti₃O₁₂ (M = La, Sm, Nd, and Eu) showed markedly higher catalytic activity compared to traditional N doped TiO₂ (N-TiO₂) and pure bismuth titanate (Bi₄Ti₃O₁₂, BIT) for MO photocatalytic degradation under visible light irradiation. The high photocatalytic performance of Bi_3.25M_0.75Ti₃O₁₂ photocatalysts could be attributed to the strong visible light absorption and the recombination restraint of the e^?/h⁺ pairs resulting from doping of rare earth metal ions. Furthermore, BET nanowires exhibited the highest photocatalytic activity.     

Performance analysis of a free-space laser communication system with a Gaussian Schell model

In practice, due to reasons related to the characteristics of the laser device and the inevitable error of the processing technique, a laser beam emitted from a communication terminal is represented by the Gaussian–Schell model. The incident optical intensity at the receiver aperture is affected by the source coherence parameter through atmospheric turbulence. With full consideration of both the average optical intensity and the scintillation, the statistical distribution of the optical intensity and the average bit error rate (BER) of an on-off keying (OOK) receiver is obtained. The results indicate that the effect on the degradation of the average optical intensity is reduced with a smaller beamwidth. The performance of the OOK receiver degrades drastically with the increasing source coherence parameter. Moreover, when the beamwidth becomes larger, the BER₀ with a consistent source coherence parameter shifts to the side of lower BER. The goal of this work is to improve the redundancy design of the laser communication receiver system.     

Electrical charge conductivity behavior of electrodeposited Cu2O/ZnO heterojunction thin films on PET flexible substrates by impedance spectroscopy analysis

The bottom-up self-assembly Cu₂O/ZnO heterojunction thin films electrodeposited on indium tin oxide flexible substrate (polyethylene terephthalate, PET) have been investigated by impedance spectroscopy. It is used to study the electric conductivity of the Cu₂O/ZnO heterojunction thin films combined electric modulus and impedance plots. The electric modulus and impedance as a function of the frequency analysis show the distribution of the relaxation times due to the hopping of charge carriers among defects in the Cu₂O/ZnO heterojunction thin films. The values of activation energies derived from the electric modulus and impedance are found to be 0.42 and 0.40 eV, respectively, which is close to the activation energy (0.28 eV) of dc electrical conductivity and activation energy of ac conductivity (0.45–0.14 eV at the range of 100 Hz–1 MHz) in the temperature range over 303–423 K.     

Study on laser-alloyed self-lubricating anti-wear composite coating after ageing treatment

The NiCr/Cr₃C₂-10CaF₂ (wt-%) composite coatings were fabricated on Ti-6Al-4V alloy by laser surface alloying. Ageing treatments were performed at 600°C for 0, 24, 48 and 96?h, respectively. Microstructure and tribological properties of the as-laser-alloyed and aged composite coatings were investigated systematically. Results showed that microstructure became more homogeneous after ageing at 600°C for 48?h. Wear rates and friction coefficients of the aged composite coatings were slightly higher than that of the as-laser-alloyed coating. It indicates that microstructure and tribological properties of the composite coatings present good high-temperature stability.     

降低高炉燃料比的措施及效果

针对原料不稳定、高炉喷煤量低、热风炉风温低且不稳定现象,通过加强槽下筛分管理,恢复热风炉助燃空气和煤气的双预热,对炉前输煤管路、喷枪装置进行改造,采用焦丁混装技术等措施,安钢永通2号高炉燃料比由535 kg/t Fe降到了527 kg/t Fe,实现了高炉低成本运行。     

全钒氧化还原液流电池电解液的研究

研究在40℃温度下,添加剂对全钒氧化还原液流电池电解液稳定性的影响.通过采用硫酸亚铁铵溶液对钒电池电解液进行电位滴定,定量分析钒电池电解液中不同价态钒离子的浓度;利用循环伏安曲线扫描,分析添加剂的引入对电解液电化学性能的影响.结果表明:温度40℃时,添加剂对五价钒溶液稳定性的影响次序为:尿素>硫酸钾>CTAB>草酸铵>草酸钠;添加剂对钒溶液氧化活性的影响为:草酸钠>尿素>硫酸钾>CTAB>草酸铵;对还原活性的影响为:草酸铵>草酸钠>硫酸钾>CTAB>尿素;对氧化还原反应可逆性的影响为:尿素>草酸钠>硫酸钾>CTAB>草酸铵.