Al-Sn复合材料的制备及其水反应产氢效率

为提高Al和水的反应活性,采用高能球磨法制备了Al-Sn复合材料,通过SEM、激光粒径分析、XRD等方法表征了Al-Sn复合物的微观结构,研究了Al-Sn复合材料的水反应活性,考察了颗粒粒径、水介质、起始温度、球磨参数变化对Al-Sn复合物水反应活性的影响。实验结果表明,高能球磨法及金属Sn的加入能够大幅提高Al与水反应的活性,制备的Al-Sn复合材料与水反应的氢气产率达83.92%,快速期最大产氢速率为359mL/(min·g)。

DETERMINATION OF ACTIVITY OF AI IN SOLID Cu-Al ALLOYS

Activities and activity coefficients of Al in solid Cu-AI alloys have been determined by means of solid electorlyte galvanic cells Al(a_1 , in alloy), Al_2O_3 | ZrO_2· Y_2O_3 | Ni, NiO and Al(a_1 , in alloy), Al_2O_3 | Na, βAl_2O_3 | Al(a_2 , in alloy), Al_2O_3

基于改进f_(aln)函数的永磁同步电机自抗扰控制

针对干扰对永磁同步电机控制系统的影响,提出了一种基于改进f_(aln)函数的永磁同步电机自抗扰控制方法。设计了永磁同步电机自抗扰控制器,通过分析f_(al)函数对自抗扰控制器的影响,提出了一种限幅的改进f_(aln)函数,进而设计了扩张状态观测器,证明了改进后的观测器的收敛性。通过对比试验证明了基于改进f_(aln)函数的永磁同步电机自抗扰控制方法相对于传统自抗扰控制具有更好的抗干扰性能。

Physics-Based Active Learning for Design Space Exploration and Surrogate Construction for Multiparametric Optimization

The sampling of the training data is a bottleneck in the development of artificial intelligence(AI)models due to the processing of huge amounts of data or to the difficulty of access to the data in industrial practices.Active learning(AL)approaches are useful in such a context since they maximize the performance of the trained model while minimizing the number of training samples.Such smart sampling methodologies iteratively sample the points that should be labeled and added to the training set based on their informativeness and pertinence.To judge the relevance of a data instance,query rules are defined.In this paper,we propose an AL methodology based on a physics-based query rule.Given some industrial objectives from the physical process where the AI model is implied in,the physics-based AL approach iteratively converges to the data instances fulfilling those objectives while sampling training points.Therefore,the trained surrogate model is accurate where the potentially interesting data instances from the industrial point of view are,while coarse everywhere else where the data instances are of no interest in the industrial context studied.

Lu-Mg和Lu-Al合金热力学性质的理论分析

文章利用Miedema生成热模型计算Lu-Mg和Lu-Al二元合金的混合焓、过剩熵、过剩吉布斯自由能以及各组元的活度。结合Butler方程,计算Lu-Mg和Lu-Al合金熔体的表面张力以及表面相中各元素含量。研究结果表明,Lu-Mg和Lu-Al合金熔体的混合焓、过剩熵以及过剩吉布斯自由能都为负值,同时各组分活度较理想熔体有着一定负偏差,说明Lu与Mg和Al原子之间存在显著的相互作用力。Lu-Mg和Lu-Al合金熔体表面张力随Mg和Al含量的增加而减小,Mg和Al元素均会向熔体表面富集。

Structure and visible photocatalytic activity of nitrogen-doped meso-porous TiO_2 layer on Ti6Al4V substrate by plasma-based ion implantation

The nitrogen-doped porous TiO2 layer on Ti6Al4V substrate was fabricated by plasma-based ion implantation of He, O and N. In order to increase the photodegradation efficiency of TiO2 layer, two methods were used in the process by forming mesopores to increase the specific surface area and by nitrogen doping to increase visible light absorption. Importantly, TiO2 formation, porosity architectures and nitrogen doping can be performed by implantation of He, O and N in one step. After implantation, annealing at 650 ℃ leads to a mixing phase of anatase with a little rutile in the implanted layer. By removing the near surface compact layer using argon ion sputtering, the meso-porous structure was exposed on surfaces. Nitrogen doping enlarges the photo-response region of visible light. Moreover, the nitrogen dose of 8×1015 ion/cm2 induces a stronger visible light absorption. The photodegradation of rhodamine B solution with visible light sources indicates that the mesopores on surfaces and nitrogen doping contribute to an apparent increase of photocatalysis efficiency.

高氯酸盐对Al/PTFE活性材料热反应行为的影响

为了研究高氯酸盐对Al/PTFE二元活性材料热反应行为的影响,选用高氯酸钾(KClO_(4))和高氯酸钠(NaClO_(4))作为填充材料,采用湿混法分别制备了KClO_(4)/Al/PTFE和NaClO_(4)/Al/PTFE三元活性材料样品。利用扫描电子显微镜(SEM)观察了样品的微观形貌;采用同步热分析技术(TGA-DSC)、 X射线衍射技术(XRD)以及自建的燃烧测试装置,对高氯酸盐/Al/PTFE三元活性材料体系的热性能和燃烧性能进行了研究。结果显示:高氯酸盐粉末和Al粉均匀分布在PTFE基底上。通过TG-DSC同步热分析实验发现高氯酸盐/Al/PTFE活性材料体系分解反应的开始温度均低于Al/PTFE活性材料。其中,KClO_(4)/Al/PTFE三元活性材料的分解放热量略低于NaClO_(4)/Al/PTFE三元活性材料;KClO_(4)的分解温度在PTFE的催化作用下降低,且KClO_(4)/Al/PTFE三元活性材料的放热峰值温度也降低了29.1℃;而NaClO_(4)/Al/PTFE三元活性材料的放热峰值温度提高了7.5℃。相比NaClO_(4),KClO_(4)的加入有助于C的利用。在点火实验中,高氯酸盐的引入可有效增加Al/PTFE活性材料体系的燃烧持续时间、爆燃持续时间,并提高了最高压力,但也降低了体系的升压速率、增加了达到最大压力的时间。

Modification of constitutive model and evolution of activation energy on 2219 aluminum alloy during warm deformation process

To investigate the flow behavior of 2219 Al alloy during warm deformation, the thermal compression test was conducted in the temperature range of 483-573 K and the strain rate range of 0.001-5 s^-1 on a Gleeble-3500 thermomechanical simulation unit. The true stress-true strain curves obtained showed that the flow stress increased with the decrease in temperature and/or the increase in strain rate and the softening mechanism primarily proceeded via dynamic recovery. The modification on the conventional Arrhenius-type constitutive model approach was made, the material variables and activation energy were determined to be dependent on the deformation parameters. The modified flow stresses were found to be in close agreement with the experimental values. Furthermore, the activation energy obtained under different deformation conditions showed that it decreased with the rise in temperature and/or strain rate, and was also affected by the coupled effect of strain and strain rate.

Investigation of the characteristics and deactivation of catalytic active center of Cr-Al_2O_3 catalysts for isobutane dehydrogenation

Deactivation mechanism of Cr-Al2O3catalyst and the interaction of Cr-A1 in the dehydrogenation of isobutane, as well as the nature of the catalytic active center, were studied using XRD, SEM, XPS, H2-TPR, isobutane-TPR and TPO techniques. The results revealed that the deactivation of Cr-Al2O3 catalyst was mainly caused by carbon deposition on its surface. The Cr3＋ ion could not be reduced by hydrogen but could be reduced to Cr2＋ by hydrocarbons and monoxide carbon. The active center for isobutane dehydrogenation could be Cr2＋/Cr3＋ produced from Cr6＋ by the on line reduction of hydrocarbon and carbon monoxide. The binding energy of Al3＋ was strongly affected by the state of chromium cations in the catalysts.

Effect of mechanical activation on TiC synthesis reaction in Al-Ti-C powder mixture

After milling in a high energy ball miller for various times, the synthesis reaction process of the Al Ti C powder mixture were investigated by difference thermal analysis (DTA) and X ray diffractometry (XRD). According to the patterns of reaction peaks on the DTA curves, the activation energy of each reaction was calculated. The experimental results of DTA show that the synthesis reaction of Al Ti C powder mixture can be enhanced after high energy milling. The longer the milling time, the lower the reaction temperature. The synthesis reaction of TiC is transformed from Ti+C→TiC to Al 3Ti+C→TiC+3Al with long period milling. Meanwhile, the activation energy of the reaction reduces with increasing milling time. The effect of milling time on reduced activation energy for low temperature region is more significant than that for high temperature region.

Direct active soldering of Al_(0.3)CrFe _(1.5)MnNi_(0.5) high entropy alloy to 6061-Al using Sn-Ag-Ti active solder

Al0.3CrFe1.5MnNi0.5 high entropy alloys(HEA)have special properties.The microstructures and shear strengths of HEA/HEA and HEA/6061-Al joints were determined after direct active soldering(DAS)in air with Sn3.5Ag4Ti active filler at 250°C for 60 s.The results showed that the diffusion of all alloying elements of the HEA alloy was sluggish in the joint area.The joint strengths of HEA/HEA and HEA/6061-Al samples,as analyzed by shear testing,were(14.20±1.63)and(15.70±1.35)MPa,respectively.Observation of the fracture section showed that the HEA/6061-Al soldered joints presented obvious semi-brittle fracture characteristics.

Corrosion and discharge performance of Mg-9%Al-2.5%Pb alloy as anode for seawater activated battery

To obtain a new kind of Mg?Al?Pb alloy anode material with low content of Pb, the corrosion and discharge behavior of Mg?9%Al?2.5%Pb (hereafter in mass fraction) alloy were investigated by immersion tests and electrochemical techniques, and compared with those of Mg?6%Al?5%Pb alloy. The results indicate that Mg?9%Al?2.5%Pb alloy exhibits a lower self-corrosion rate and higher utilization efficiency in contrast with Mg?6%Al?5%Pb alloy because of the higher content of Al. As the result of the decrease of Pb content, the discharge activity of Mg?9%Al?2.5%Pb alloy is relatively weaker but still meets the requirement of anode. These results reveal that Mg?9%Al?2.5%Pb alloy with a low content of Pb can serve as a good candidate for the anode material used in seawater activated battery.

A study of the relationship between expression level of TRF1 protein and telomerase activity in human acute leukemia

Objective： To study the expression level of TRF1 （telomeric repeat binding factor 1） protein in human acute leukemia and relationship between expression level of TRF1 protein and telomerase, Methods： A quantitative Western±Blot technique was developed using anti±TRF1^33±277 monoclonal antibody and GST±TRFI purity protein as a standard to further determine the expression level of TRF1 protein in total proteins extracted from clinical specimens. Results： Bone marrow tissues of 20 acute leukemia patients were studied, 11 healthy donors＇ bone marrows were taken as a control. The expression level of TRF1 protein was significantly higher （P〈0.01） in normal bone marrow （（2.2174±0.462） μg/μl） than that of acute leukemia patients （（0.7544±0.343） μg/μl）, But there was no remarkable difference between ALL and ANLL patients （（0.6184±0.285） μg/μl vs （0.8454±0.359） μg/μl, P〉0.05）. After chemotherapy, TRFI expression level of patients with complete remission elevated （（0.7724±0.307）/μg/μl vs （1.6834±0,344）μg/μl, P〈0.01 ）, but lower than that of normal （（2.2174±0.462）/μg/μl, P〈0.01）. There was no significantly difference after chemotherapy （（0.7264±0.411） μg/μl vs （0.895±0.339） μg/μl,p〉0.05）. TRF1 expression level of patients with complete remission is higher than that of patients without complete remission （（1,683±0.344）μg/μl vs （0.895±0.339）μg/μl P〈0.01）. All samples were determined for telomerase activity. It was confirmed that the activity of telomerase in normal bone marrow was lower than that of acute leukemia patients （（0.125±0.078） μg/μl vs （0.765±0.284）μg/μl, P〈0.01）. There was no significant difference of expression level ofTRF I protein between ALL and ANLL patients （（0.897±0.290） μg/μl vs （0.677±0.268） μg/μl, P〉0.05）. After chemotherapy, telomerase activity of patients with complete remission decreased （（0.393±0.125） μg/μl）, but was still higher than that of normal （（0.125±0.078） μg/μl, P〈0.01）. Conclusion： The expression level of TRF1 protein has correlativity to the activity of telomerase （P〈0.001）.

CODEPOSITION OF ALUMINUM AND SILICON ON PURE MOLYBDENUM SUBSTRATE USING HALIDE ACTIVATED PACK CEMENTATION TREATMENTS

A multi-component diffusion coating has been developed to protect Mo-based alloys from high temperature environmental attack. Aluminum addition was made during the coating process to improve the oxidation resistance by developing hexagonal Mo(Si, Al)2 through the development of the halide activated pack cementation coating process on pure Mo substrate. The results show that Mo(Si, Al)2 formed as a main phase on the surface and a little amount of Mo5Si3 also formed. The total thickness of coating is tens ofμm at 1373K. During the cyclic oxidation test at high temperature(at about 1323K in air), mullite (3Al2O3.2SiO2) and some SiO2 formed. The addition of Al is beneficial for MoSi2 coating and the Al-doped coating exhibited only a small weight gain and protected the Mo substrate, while the MoSi2 coating without Al suffered a significant weight loss, indicating a loss of volatile MoO3 after cycles.

In situ formation of Zr_2Al_3C_4/Al_2O_3 composites by combustion synthesis with PTFE and thermal activations

Preparation of Zr2Al3C4-Al2O3 in situ composites was investigated by self-propagating high-temperature synthesis(SHS)involving both aluminothermic reduction of ZrO2 and chemical activation of PTFE(Teflon).The starting materials included ZrO2,Al,carbon black and PTFE.In addition to the conventional SHS method,the experiments were conducted by a chemical-oven SHS(COSHS)route to thermally assist the synthesis reaction.The threshold amount of 2%(mass fraction)PTFE was required to induce self-sustaining combustion.When the conventional SHS scheme was utilized,due to low combustion temperatures between 1152 and 1272°C and insufficient reaction time,the dominant carbide forming in the composite was ZrC instead of Zr2Al3C4.On the other hand,the COSHS technique increased the combustion temperature of the reactant compact to about 1576°C,lengthened the high-temperature duration for the reaction,and prevented Al vapor from escaping away.As a consequence,Zr2Al3C4-Al2O3 composites with a small amount of Zr3Al3C5 were obtained.The microstructure of the COSHS-derived product showed that plate-like Zr2Al3C4 grains were about 2μm in thickness and 10-30μm in length,and most of them were closely stacked into a laminated configuration.

THERMAL ACTIVATION ANALYSIS ON STRAIN RATE DEPENDENCE OF HIGH TEMPERATURE TENSILE PROPERTIES IN TiAl ALLOY

Tensile properties of a two phase γ Ti 47Al 1.5Cr 0.5Mn 2.8Nb alloy with a duplex microstructure were tested under strain rates ranging from 5×10 -5 to 5×10 -3 s -1 at temperatures from 1 123 K to 1 273 K. It was found that there exists approximately linear relationship between the flow stresses and the logarithm of the strain rate at different temperatures. The strain rate dependence was analyzed by thermal activation theory, and dislocation climbing has been identified as the rate controlling mechanism.

Al/PTFE活性材料在炸药爆轰作用下的响应特性研究

为探究铝—聚四氟乙烯(Al/PTFE)活性材料在炸药爆轰作用下的响应特性,采用JO-8及DHL两种高爆速炸药对活性材料进行了端面及对碰爆轰加载试验。通过转镜式高速扫描相机记录了炸药爆轰波及活性材料激发的响应迹线,并结合理论分析获取了2种爆轰加载方式下活性材料内的冲击波压力值。结果表明:端面爆轰加载下,Al/PTFE活性材料在初始高压约为33.59 GPa的入射冲击波作用下发生剧烈反应,但随着冲击波压力衰减,反应速率迅速降低,表明该活性材料不能发生自持爆轰;对碰爆轰加载下,Al/PTFE活性材料受到持续高压作用,虽然由滑移爆轰加载产生的入射冲击波初始压力仅为15.76 GPa,但冲击波在活性材料的中心处发生汇聚叠加,形成高压集中区,在该区域内发生了“类爆轰”反应,反应速率达到4 mm/μs,但其反应过程还需要进一步研究。此外,研究还表明,同轴组合装药结构可使活性材料受到炸药爆轰产生的持续强冲击加载,不仅能够显著提升其反应速率,还可避免其反应无法自持的问题,可为相关战斗部装药的设计提供参考。

Hot deformation behavior of Fe–27.34Mn–8.63Al–1.03C lightweight steel

Hot compression tests were performed to investigate the hot deformation behavior of Fe–27.34Mn–8.63Al–1.03C lightweight steel and optimize the hot workability parameters. The temperature range was 900–1150℃ and the strain rate range was 0.01–5 s^(-1)on a Gleeble-3800 thermal simulator machine. The results showed that the flow stress increased with decreasing deformation temperature and increasing strain rate. According to the constitutive equation, the activation energy of hot deformation was 422.88 kJ·mol^(-1). The relationship between the critical stress and peak stress of the tested steel was established, and a dynamic recrystallization kinetic model was thus obtained. Based on this model, the effects of strain rate and deformation temperature on the volume fraction of dynamically recrystallized grains were explored. The microstructural examination and processing map results revealed that the tested steel exhibited a good hot workability at deformation temperatures of 1010–1100℃ and strain rate of 0.01 s^(-1).

Cu对Al-50%Si合金法提纯太阳能级多晶硅过程中初晶硅Al含量影响研究

Al-Si合金法提纯具有生产成本低、除杂效率高、副产物单一等特点,是一种极具潜力的太阳能级多晶硅原料的制备方法。在该工艺路线中,Al作为溶剂不可避免地会对Si产生污染,如何降低初晶硅中Al的含量是亟需解决的问题之一。本文通过向Al-50%Si合金中加入Cu,分析Cu对合金溶液热力学性能的影响,结合Cu的存在方式,探讨Cu对Al污染的抑制作用。结果表明:在Al-50%Si合金中添加10%(质量分数)Cu后,合金中Al的活度系数降低至0.7148;初晶硅中Al的含量从250.960 mg/kg降低到181.637 mg/kg,比未添加Cu时减少了27.62%,同时,Cu在初晶硅中的残留仅为12.6 mg/kg,低于Cu在Si中的固溶度。可见,在Al-Si合金中引入Cu并未对初晶硅造成二次污染。因此,采用Al-Si-Cu三元合金体系进行提纯制备太阳能级多晶硅能够有效抑制Al对初晶硅的污染。

Al^(3+)对污泥自热高温微氧消化产酸及有机物释放的影响

为开发利用剩余污泥消化液中的有机物,向污泥自热高温微氧消化(ATMAD)体系投加不同量的AlCl_(3)·6H_(2)O,研究Al^(3+)对该体系内有机物、挥发性脂肪酸(VFA)及氨氮、磷酸盐释放的影响.结果表明,消化体系内存在的Al^(3+)抑制了有机物的分解转化,改变了污泥消化液中有机组分的含量与构成.对照组中VFA的最大产量是Al^(3+)浓度为1.0g/L的实验组VFA产量的6.9倍.消化结束后Al^(3+)浓度为1.0g/L的体系内NH_(4)^(+)-N浓度为502.06mg/L,而对照组中NH_(4)^(+)-N浓度仅为334.41mg/L.Al^(3+)也降低了体系内微生物活性.消化体系中存在的Al^(3+)不利于活性污泥ATMAD体系的产酸与稳定化,在污泥ATMAD体系中应避免引入过多的Al^(3+),以保证消化体系能够充分产酸,释放有机物,为污水处理生物脱氮提供优质碳源.