双相不锈钢中厚板在线酸洗工艺研究进展

在卧式连续喷淋酸洗机组上,利用原设备和H2SO4+(HNO_3+HF)酸洗液技术酸洗双相不锈钢中厚板,酸洗后表面出现浅灰色、下表面辊印缺陷。针对这些缺陷,以S32205双相不锈钢板为代表牌号,论述一种两段式混酸(HNO_3+HF)液酸洗方法,开展了两段式混酸(HNO_3+HF)液酸洗方法的实验室、工业化工艺试验和研究,并对原卧式喷淋酸洗生产线进行了技术改造。应用两段式混酸(HNO_3+HF)液工艺技术酸洗S32205钢板,在预先酸洗工艺段,混酸液HNO_3质量浓度为180g/L、HF质量浓度为90g/L,混酸液温度为43℃;在最终酸洗工艺段,混酸液HNO_3质量浓度为265g/L、HF质量浓度为56g/L,混酸液温度为43℃,一次酸洗合格率达到95%以上。从技术上解决了双相不锈钢中厚板酸洗后表面出现的浅灰色、下表面辊印缺陷,酸洗后的钢板表面呈银白色,色泽均匀,满足了双相不锈钢板产品标准关于表面质量的要求。     

板坯电渣重熔炉结晶器报废原因分析及改进措施

着重对舞钢公司40 t板坯电渣重熔炉结晶器的报废原因进行了分析研究,阐述了针对该类型结晶器所制定的维护、修复与报废标准,同时提出了延长结晶器使用寿命和降低结晶器使用成本方面的一些措施和设想展望。     

RED算法的稳定性:基于非线性控制理论的分析

随机旱期检测（Radom Erly Detection,ERD)算法是主动队列管理（ActiveQueue Management,AQM)的有效实现算法，有关它性能的研究是近来网络研究的一个热点，在某些网络配置和负载状态下，RED存在稳定性问题，已有的关于RED稳定性的研究用不同的方法，从不同的角度定性或定量地揭示了可能的原因，并给出了稳定运行的工作区间，但没有对等幅振荡的队列行为给出一个合理的解释，在该文中，作者利用描述函这一非线性控制理论中经典的分析方法，分析了RED和getle-RED的工作特性，认为分组丢弃概率曲线中的非线性结构诱发的自激振荡是队列呈现周期运动的本质原因；虽然相比较而言，getle-RED比RED有更宽的稳定工作区间，但也是非常有限公司，解决AQM稳定性的理想途径是设计更为鲁棒的线性控制器。     

Direct Friction Welding of TiAl Alloy to 42CrMo Steel Rods

The effect of post-weld heat treatment (PWHT) on the mechanical properties and microstructure of direct friction-welded joint between TiAl alloy and 42CrMo steel rods was investigated in this paper. It was found that solid joint between TiAl alloy and 42CrMo steel could be obtained without adding interlayer. After PWHT at 580°C for 2 h, the tensile strength of the joint reached 405 MPa, and fracture happened through the TiAl alloy substrate with quasi-cleavage features. The tempered sorbite formed near the interface, improving the joint strength significantly. It was found that TiFe₂, TiAl, and small amount of TiC brittle phases formed at the interface, and the interfacial layer was as thin as 2–5 µm. The precipitated phases were 1 µm in average size, and distributed discontinuously at the interface.     

探针法测量月壤温度的可靠性分析

建立了月表辐射条件下探针和月壤组成的多层介质内二维非稳态导热模型.采用非均匀网格,数值模拟了月壤和探针间的耦合热效应,分析了探针所表征月壤温度的可信度.结果表明,因初始条件不同,探针插入后和月壤互有影响,其中探针对月壤的影响范围及时间有限.由于月壤深度方向上温度梯度的影响,探针不同位置的温度值不同.月壤的弱导热性导致探针的温度值与月壤的存在偏差,且差值并不一定随测量时间的增长而变小.     

脉冲偏压对电弧离子镀TiNbN硬质薄膜相结构的影响

用电弧离子镀设备,在其他工艺参数相同的条件下,通过仅改变脉冲偏压幅值的方法分别沉积TiNbN硬质薄膜,考察脉冲偏压对薄膜相结构的影响.结果表明,TiNbN硬质薄膜的相结构随脉冲偏压幅值的变化而变化:当幅值为-300 V时,得到TiN类型的(TiNb)N的固溶体;-600 V时,得到TiN和δ-NbN的混合相结构;而在-900 V时,则得到TiN和δ-NbN以及β-Nb2N三相混合结构.分析表明,脉冲偏压能够改变薄膜相结构,这与不同偏压提供的离子沉积能量,能够分别满足各个化合物生成自由能的热力学条件有关.     

铝蜂窝结构的冲击动力学性能的试验及数值研究

通过分析蜂窝胞元中取出的Y型单元,推导了正六边形蜂窝胞元的相对密度计算公式,并分析了蜂窝的典型动态压溃过程;通过自制刀具切割蜂窝板得到了外径为西Φ100的三种规格(0.06 mm(胞元壁厚t)×4 mm(胞元边长l)×60 mm(试件高h)、0.06 mm(t)×6 mm(l)×30 mm(h)和0.06 mm(t)×10 mm(l)×50 mm(h))的蜂窝试件,并在标准冲击试验机上得到了它们在5m/s名义初始压溃速度下的应力-应变曲线;在保证与试验条件相同的前提下,简化蜂窝单元为Y型单元,辅以适当的边界条件,通过数值方法研究了此三种蜂窝试件的动态压溃过程,并将得到的应力-应变曲线与试验得到的应力-应变曲线作了比较,发现它们吻合的很好;最后将理论得到的弹性坍塌应力和塑性坍塌应力与相应的试验值和仿真值进行了对比,发现塑性坍塌应力的仿真值和试验值比较接近,而理论值则小于它们.最后结合蜂窝片标准冲击试验结果设计出可用于着陆缓冲装置着陆缓冲的蜂窝减振器,试验结果表明缓冲后加速度的试验值和设计值吻合的较好.     

纳米氧化铝的晶型及粒度对其红外光谱的影响

利用硫酸铝铵热解法,通过控制焙烧温度,制备了不同晶型和粒度的纳米Al2O3.XRD物相分析表明,焙烧至900℃可得到纯γ-Al2O3,1200℃发生相转变,生成α-Al2O3.用Scherrer公式计算得到了各样品的晶粒度.对所制备的纳米Al2O3的红外光谱进行了详细研究.结果表明,不同晶型的纳米Al2O3具有不同的红外光谱特征,因此,红外光谱可以作为一种定性判断Al2O3是否发生了相转变的辅助手段.实验中发现所制备的纳米Al2O3的红外光谱存在吸收峰的蓝移和宽化,对出现此现象的原因进行了分析讨论.最后,对纳米金属氧化物材料出现谱移现象的原因进行了归纳总结.     

Carbon isotopes profiles of human whole blood, plasma, red blood cells, urine and feces for biological/biomedical 14C-accelerator mass spectrometry applications

Radiocarbon ((14)C) is an ideal tracer for in vivo human ADME (absorption, distribution, metabolism, elimination) and PBPK (physiological-based pharmacokinetic) studies. Living plants peferentially incorporate atmospheric (14)CO(2) versus (13)CO(2) versus (12)CO(2), which result in unique signature. Furthermore, plants and the food chains they support also have unique carbon isotope signatures. Humans, at the top of the food chain, consequently acquire isotopic concentrations in the tissues and body fluids depending on their dietary habits. In preparation of ADME and PBPK studies, 12 healthy subjects were recruited. The human baseline (specific to each individual and their diet) total carbon (TC) and carbon isotope (13)C (δ(13)C) and (14)C (F(m)) were quantified in whole blood (WB), plasma, washed red blood cell (RBC), urine, and feces. TC (mg of C/100 μL) in WB, plasma, RBC, urine, and feces were 11.0, 4.37, 7.57, 0.53, and 1.90, respectively. TC in WB, RBC, and feces was higher in men over women, P < 0.05. Mean δ(13)C were ranked low to high as follows: feces < WB = plasma = RBC = urine, P < 0.0001. δ(13)C was not affected by gender. Our analytic method shifted δ(13)C by only ±1.0 ‰ ensuring our F(m) measurements were accurate and precise. Mean F(m) were ranked low to high as follows: plasma = urine < WB = RBC = feces, P < 0.05. F(m) in feces was higher for men over women, P < 0.05. Only in WB, (14)C levels (F(m)) and TC were correlated with one another (r = 0.746, P < 0.01). Considering the lag time to incorporate atmospheric (14)C into plant foods (vegetarian) and or then into animal foods (nonvegetarian), the measured F(m) of WB in our population (recruited April 2009) was 1.0468 ± 0.0022 (mean ± SD), and the F(m) of WB matched the (extrapolated) atmospheric F(m) of 1.0477 in 2008. This study is important in presenting a procedure to determine a baseline for a study group for human ADME and PBPK studies using (14)C as a tracer.