电点火头蘸药过程反应失效分析

为解决某电点火头在蘸药过程发生反应导致点火药失效问题,采用化学分析、DSC热分析、红外光谱分析、X衍射分析技术对影响点火头生产工艺的因素进行综合分析,设计DSC方法模拟反应程度与材料的关系.结果表明,点火药与配漆溶剂丙酮在室温较高时,易发生放热反应,放出的热量加剧反应,从而引起点火药被反应消耗而失效.可通过降低工房温度、缩短蘸药时间、改变配漆溶剂、控制铬酸铅原材料质量等方面改进,以避免点火药失效.     

Ti-45Al-7Nb-2V-2Cr涂层与TA2钛合金电偶腐蚀行为

采用超音速微粒沉积技术在5083铝合金表面制备γ-TiAl基Ti-45Al-7Nb-2V-2Cr合金耐蚀防护涂层,实现γ-TiAl基涂层的原态制备,并对涂层微观结构及电化学性能进行研究。结果表明：在涂层中的Al、V元素富集区,喷涂颗粒发生显著的塑性变形,有利于TiAl合金颗粒的沉积成形;通过在5083铝合金表面制备TiAl合金防护涂层可使其与TA2钛合金的接触腐蚀电流由16.2μA降为0.191μA,接触腐蚀敏感性由E级降到A级,喷涂件可与TA2钛合金直接接触使用,解决了铝合金与钛合金的接触腐蚀防护问题。     

New Insights into the Decisional Use of Process Capability Indices via Hypothesis Testing

Process capability indices C_p, C_pk, and C_pm are still nowadays widely used in industry—thanks to their easy formulation and implementation. This paper aims to give new mathematical insights in order to support their use in decision‐making via hypothesis testing. The minimum sample size usually needed in the applications to achieve fixed significance level and power is reported in light of the new mathematical aspects for C_pk and C_pm, which avoid misleading conclusions and the use of extensive numerical experiments. In addition, power curves for C_pk and C_pm, which have not previously appeared in the literature before, are also presented. Lastly, easy‐to‐follow diagrams for hypothesis testing with C_pk and C_pm and two critical scenarios for C_pm are included in the paper to facilitate the applicative use and the comprehension of the novel inferential aspects. Copyright © 2014 John Wiley & Sons, Ltd.     

一种温拌剂对普通沥青和SBS改性沥青混合料的降温效果评价

首先介绍了采用温拌剂的必要性,其次进行了温拌降黏材料Sasobit应用于普通沥青和SBS改性沥青后的黏温曲线试验和沥青混合料体积特性试验,最后对两者的降温效果进行了评价。试验表明,Sasobit温拌沥青混合料可节约燃油,大大减小对施工人员身体健康的危害。     

癸酸—月桂酸二元复合相变储能材料循环热稳定性

以研究癸酸—月桂酸二元复合相变储能材料在循环相变过程中的热稳定性为目的,搭建了实现相变材料加速热循环过程的实验平台,并利用差示扫描量热仪(DSC)测定了经过0,800,1 600,2 400,3 200,4 000次加速热循环后相变材料的相变温度和相变潜热。经过4 000次循环后,相变温度下降了0.8℃,相变潜热降低为初始值的92.08%。结果表明:随着循环次数的增加,该相变材料的相变温度变化微小,相变潜热有所降低,其热稳定性比较好。基于实验结果,讨论了此种相变材料在太阳能及建筑节能领域的应用前景。     

温度对P110钢在水泥挤出液中钝化膜性能的影响

目的 探究P110套管钢在不同温度下生成的钝化膜的性能差异,找到能使P110套管钢生成最稳定钝化膜的温度,同时了解该温度下氯离子对钝化膜的破坏规律。方法 利用极化曲线、交流阻抗谱（EIS）和Mott-Schottky测试,研究了P110套管钢材料在pH值为13.0的水泥挤出液中浸泡4 d的钝化行为,讨论了在低、中、高（40、65、90 ℃）三种温度下生成的钝化膜的稳定性,并用扫描电子显微镜（SEM）对各试样表面微观形貌进行观察。最后在溶液中加入不同浓度的氯离子,通过测试极化曲线了解氯离子对钝化膜的破坏规律。结果 试样在40、65、90 ℃下的腐蚀电流密度分别为2.2727×10?6、4.0452×10?7、1.7081× 10?5 A/cm2,膜电阻分别为100 100、238 200、5480 Ω?cm2。40、65 ℃下所生成的钝化膜呈p型半导体特征,而90 ℃下呈双极型半导体特征。65 ℃下,随着氯离子浓度的增加,试样的腐蚀电位负移,耐蚀性逐渐降低,腐蚀速率增大,当浓度达到0.1 mol/L时,钝化膜的膜层结构已被破坏。结论 P110套管钢在pH值为13.0的水泥挤出液中浸泡4 d,表面能够生成钝化膜。在65 ℃溶液中生成的钝化膜耐蚀性最好,膜层结构更加致密,40 ℃次之,90 ℃最差。氯离子对钝化膜有侵蚀作用,高浓度的氯离子可以直接导致稳定钝化膜的破坏。     

Preparation of Ni–P–La alloy as a novel electrocatalysts for hydrogen evolution reaction

Ternary Ni–P–La alloy was synthesized by the co-electrodeposition method on the copper substrate. The energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used for characterization of the synthesized alloy. The electrochemical performance of the novel alloy was investigated based on electrochemical data obtained from steady-state polarization, Tafel curves, linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) in alkaline solution and at ambient temperature. The results showed that the microstructural properties play a vital purpose in determining the electrocatalytic activity of the novel alloys. Also, the HER on investigated alloys was performed via the Volmer-Heyrovsky mechanism and Volmer step as RDS in this work. Ni–P–La catalyst was specified by ƞ₂₅₀ = −139.0 mV, b = −93.0 mV dec⁻¹, and j_o = −181.0 μA cm⁻². The results revealed that the Ni–P–La catalysts have a high potential for HER electrocatalysts in 1M NaOH solution.     

Post-forming monotonic and cyclic behavior in a HSLA steel sheet after large deformations by in-plane compression

The effects of large prestrains (18–40%), produced by in-plane compression, on the asymmetry and the anisotropy of the stress response and on the fatigue life are investigated under fully reversed axial strain for a 345 MPa yield strength V–N high strength low alloy steel sheet. After prestraining, the hysteresis loops are asymmetric and the stress response is anisotropic, i.e., the response differs in directions parallel and perpendicular to that of the compressive prestrain. To understand the cyclic flow stress asymmetry, monotonic tension and compression tests were conducted in these two directions after prestraining. It is shown that the loop asymmetry is related to the Bauschinger effect after prestraining. Two cyclic stress strain curves, one corresponding to the tension side of the hysteresis loops and the other to the compression side, are defined to accurately describe the post-prestraining behavior. The amount of strengthening gained by prestraining is partially retained after cycling. Prestraining increases the fatigue life at low strain amplitudes but decreases it at high strain amplitudes.