Dependence of domain wall structures on repetition n in[Pt（0.5 nm）/Co（0.4 nm）]n/NiO（1.1 nm）/[Co（0.4 nm）/Pt（0.5 nm）]n multilayers

The magnetic force microscopy and a sample vibrating magnetometer have been used to investigate the domain structure in two antiferromagnetically coupled Co/Pt multilayers.In the antiferromagnetic coupled[Pt(0.5 nm)/Co(0.4 nm)]_n/NiO(1.1 nm)/[Co(0.4 nm)/Pt(0.5 nm)]_n multilayers with perpendicular anisotropy,the antiferromagnetic interlayer coupling strength increases linearly with the repetition number n in Co/Pt multilayers.In demagnetized states,relatively shifted domain walls in the two Co/Pt multila...     

Luminescent properties dependence of water-soluble CdTe quantum dots on stabilizing agents and reaction time

The influence of stabilizing agents and reaction time on the luminescent properties of water-soluble CdTe quantum dots (QDs) was discussed. The thioglycolic acid (TGA)-CdTe ODs were characterized by TEM, XRD and FTIR. It is found that larger-size QDs can be synthesized more easily when L-cysteine (Cys) or golutathione (GSH) is chosen as stabilizing agent and TGA is proper to prepare highly luminescent QDs because of the effect between Cd²⁺ and sulfhydryl group. Furthermore, the absorption wavelength, full width at half maximum (FWHM), stokes shift, photoluminescence (PL) quantum yield and PL stability of TGA-CdTe are strongly dependent on reaction time, in which the absorption wavelength changes against reaction time with an exponential function. The TGA-CdTe QDs prepared at 2 h possess more excellent luminescent properties.     

Sodium-modification of Ca-based bentonite via semidry process

In order to improve the quality of Hunyuan inferior Ca-based bentonite (Ca-Bent), semidry process was used to modify Ca-Bent into superior Na-based bentonite (Na-Bent). The factors affecting sodium-modification were investigated. The optimized experimental parameters are obtained as follows: Na₂CO₃ dosage 4.0%, ageing time 25 d, briquetting pressure 25 MPa and briquetting moisture 20%. Under the optimization conditions, the modified Na-Bent has a colloid value of 73.6 mL/(3g), dilation of 38 mL/g and water absorption in 2 h (2HWA) of 465%, respectively. The balling results indicate that the modified Na-Bent pellets have higher drop strength and compression strength than the Ca-Bent pellets.     

半导体封装生产线工艺流程分析

本文介绍了半导体生产线后道封装流程,并对相关设备的自动化程度进行分析。     

多孔Si光学干涉法生物传感器的研究

实验制备多孔Si材料作为传感器载体,通过H2O2浸泡的方法使其表面形成Si-OH键,然后对样品进行硅烷化处理。用戊二醛作为偶联剂,通过共价键偶联法将血管紧张素-Ⅱ(Ang-Ⅱ)抗体固定到多孔Si的孔洞中。分别滴加不同浓度的抗原使其发生反应,测量傅里叶变换红外谱(FT-IR)和加入抗体前后反射谱的变化,结果表明,硅烷化效果明显,生物抗原较好固定,抗原抗体反应前后反射谱有明显红移,且红移量于滴加抗原浓度增加而增加,并呈现抗原抗体浓度于红移量的非线性关系。     

混浊海水声吸收的计算与测量研究

针对混浊海水中悬浮的泥沙颗粒形状极其复杂,使得直接、准确计算混浊海水的声吸收几乎是不可能的问题,提出一种采用悬浮泥沙颗粒的中值粒径去计算悬浮泥沙颗粒粘滞声吸收系数的方法.同时,利用纯净海水声吸收经验公式可计算混浊海水中电解质的声吸收系数.计算的混浊海水在20~60 kHz的声吸收系数与混响法测量的声吸收系数进行了对比.理论计算值和实验测量值之间的平均相对偏差为23%,最大相对偏差不超过50%.表明,若已知混浊海水中悬浮泥沙颗粒的密度、浓度、中值粒径时,则可利用纯净海水声吸收经验公式和粘滞声吸收公式来计算混浊海水的声吸收系数.     

单体与三体高速船舶粘性流场数值模拟

为了检验CFD在船舶粘性流场计算中的有效性,基于RANSE方法,对单体船型DTMB 5415和三体船FA1粘性流场进行了数值模拟.自由面处理采用VOF方法,湍流模型选用SSTk-ω模型,计算结果与试验数据进行了比较,在傅汝德数不是很高时吻合较好.计算结果表明,CFD可以用来研究复杂船型流动问题,对于阻力、伴流等重要的水动力参数,CFD能够给出与试验相一致的结果;同时VOF方法可以比较好地捕捉船舶自由面波形,对于三体船,计算结果能够清晰地反映出主体和侧体之间强烈的兴波干扰现象,可以为船型优化提供重要的参考.     

单角钢螺栓连接节点板拉剪性能研究

对某角钢塔典型节点进行足尺试验研究和有限元参数分析,考察单角钢连接节点板受拉剪时的工作性能和破坏模式.结果表明,单角钢连接节点板受拉剪时可能发生块状拉剪撕裂和受拉断裂两种破坏模式;垂直于受力方向的螺栓孔间距、顺受力方向的螺栓孔间距和节点板形状对单角钢连接节点板的极限承载力有显著的影响;偏心作用只会降低节点板的屈服破坏承载力,对其极限承载力影响甚小.通过可靠度分析,评价现有节点板设计方法用于单角钢连接节点板的适用性.     

A novel method for evaluating fatigue properties of bonding layers used in bridge deck pavement

A new method was used to evaluate the fatigue properties of the bonding layer used in the bridge deck pavement. The shear fatigue test of three bonding layers was conducted on a dynamic shear rheometer(DSR). The fatigue formulas were gained for these layers. The experimental results indicate that, at the same torque level or at the same frequency, neoprene latex asphalt bonding layer exhibits excellent fatigue performance when compared to other two bonding layers. Funded by the National Natural Science Foundation of China (No. 50878171)     

Air electrode supported manganese electrocatalysts for neutral electrolyte magnesium air cell

The catalysts of air electrode were prepared by sintering the active carbon loaded with manganese nitrate and potassium permanganate at 360 °C The air electrode was made up of a catalyst layer, a waterproof and gas-permeable layer, a current collecting substrate and a second waterproof and gas-permeable layer. The cell was assembled by the air electrode, pure magnesium anode and 10% NaCl solution used as electrolyte. The microstructures of air electrodes before and after discharging were characterized by SEM. The electrochemical behaviors of the air electrodes were determined by means of polarization curves, volt-ampere curves and constant current discharge curves. The polarization voltage of air electrode is—173 mV (vs SCE) at the current density of 50 mA/cm². The air electrodes exhibits good activity and stability in neutral electrolyte. The magnesium-air cell could work at 5 W for more than 7 h.