SBS改性沥青防水卷材在不同环境中的拉伸性能试验研究

通过试验分析了SBS改性沥青防水卷材在不同环境处理960 h的拉力保持率与延伸率保持率,以此考察了卷材在不同环境下的拉伸性能变化趋势.结果 表明:SBS改性沥青防水卷材分别经低温冻融、热空气老化、人工气候加速老化960 h后,拉伸性能并未受到太大影响,且纵向拉力、延伸率的保持率普遍高于横向拉力、延伸率的保持率.     

Electrochemical Hydrogen Storage Performances of the Si Added La-Mg-Ni-based A2B7-type Electrode Alloys for Ni/MH Battery Application

The casting and annealing technologies were applied to fabricate the La0.8Mg0.2Ni3.3Co0.2Six(x = 0-0.2) electrode alloys. The effects of Si content and annealing temperature on the structure and electrochemical performances of the alloys were investigated systematically. The analyses of XRD and SEM show that all the alloys possess a multiphase structure, involving two main phases(La, Mg)2Ni7 and La Ni5 as well as a residual phase La Ni3. The addition of Si brings on an evident increase in the La Ni5 phase and a decrease in the(La, Mg)2Ni7 phase, without altering the main phase component of the alloy, which also makes the lattice constants and cell volumes of the alloy enlarged. Likewise, the annealing treatment engenders the same action on the lattice constants and cell volumes as adding Si. Simultaneously, it gives rise to the variation of the phase abundance and the coarsening of the alloy grains. The electrochemical measurements indicate that the addition of Si ameliorates the cycle stability of the as-cast and annealed alloys significantly, but impairs their discharge capacities clearly. Similarly, the annealing treatment makes a positive contribution to the cycle stability of the alloy evidently, and the discharge capacity of the alloy shows a maximum value with annealing temperature rising. Furthermore, the high rate discharge ability(HRD) first augments and then declines with the rising of Si content and annealing temperature.     

Development of an occupant restraint system model and parametric study on equivalent crash pulse in vehicle frontal offset crash

Studies were conducted to evaluate driver injury metrics with varying crash pulse in offset crash.First,a vehicle finite element(FE) model and an occupant restraint system(ORS) model were developed and validated against tests;then,the crash pulse collected from the test vehicle was equivalent to a dual-trapezoid shape pulse which will be quantitatively described by six parameters and was put into the ORS model;finally,parametric studies were conducted to analyze the sensitivities of parameters of equivalent crash pulse on head resultant acceleration,head injury criteria(HIC),neck axial force and chest deformation.Results showed that the second peak value of the crash pulse was statistically significant on all these injury criteria(P=0.001,0.000,0.000,0.000 respectively),the first peak level had a negative significantly effect on all the criteria aforementioned except the chest deformation(P=0.011,0.038,and 0.033 respectively),and the interaction of the time-points of first and second peak values had a significant influence on head resultant acceleration(P=0.03).A higher first peak value and a lower second peak value of the crash pulse could bring deeply lower injury metrics.     

RE-Mg-Ni系A_2B_7型合金的循环稳定性及电化学贮氢动力学

为了改善La-Mg-Ni系A2B7电极合金的电化学循环稳定性,用Zr部分替代合金中的La,并采用熔体快淬技术制备了La0.75-xZrxMg0.25Ni3.2Co0.2Al0.1(x=0,0.05,0.1,0.15,0.2)电极合金.用XRD,TEM分析了合金的微观结构,结果表明,快淬不含Zr合金具有完全的纳米晶结构,而快淬含Zr合金中出现明显的非晶相,证明Zr替代有利于提高合金的非晶形成能力.铸态及快淬态合金均具有多相结构,包括两个主相(La,Mg)2Ni7及LaNi5和残余相LaNi2,Zr替代及快淬导致LaNi5相增加和(La,Mg)2Ni7相减少.Zr替代及快淬处理显著提高了合金的电化学循环稳定性,但快淬明显降低Zr0.2合金的电化学贮氢动力学;随Zr替代量的增加,5 m/s快淬合金的电化学贮氢动力学先增加后降低.     

An investigation of hydrogen storage kinetics of melt-spun nanocrystalline and amorphous Mg2Ni-type alloys

The nanocrystalline and amorphous Mg2Ni-type Mg2–xLaxNi (x=0,0.2) hydrogen storage alloys were synthesized by melt-spinning technique.The as-spun alloy ribbons were obtained.The microstructures of the as-spun ribbons were characterized by X-ray diffraction (XRD),high resolution transmission electronic microscopy (HRTEM) and electron diffraction (ED).The hydrogen absorption and desorption kinetics of the alloys were measured using an automatically controlled Sieverts apparatus,and their electrochemical kinet...     

Ni MOF对RE-Mg基储氢合金动力学性能的影响

通过化学方法制备了一种高比表面和多孔的Ni MOF,并通过X射线衍射仪(XRD),扫描电子显微镜(SEM)以及Sievert等体积方法系统地研究了不同含量的Ni MOF对Mg₉₀Ce₅Y₅合金储氢动力学的催化作用。结果表明，Ni MOF的添加大幅提高了Mg₉₀Ce₅Y₅的球磨效率，颗粒减小至其一半以下。此外，有效改善了合金的吸放氢动力学，降低合金的吸放氢活化能。当添加3%(质量分数)Ni MOF时，在3 MPa, 473 K下吸氢量达到最大值的90%仅需2 min; 573 K下完全放氢仅需30 min,是Mg₉₀Ce₅Y₅放氢速度的10倍，活化能减小至69.1 kJ/mol。然而，随着添加含量的增多，会降低复合材料的最大储氢容量。     

石墨烯负载金属与化合物的研究进展

石墨烯是一种以碳元素为基本原子经过sp²杂化，π-π共轭而紧密堆积的单层二维蜂窝状晶格结构，具有优异的物理和化学性质，在多个领域具有优异性能而成为研究热点。因石墨烯比表面积大，可作为基体，所形成的石墨烯基复合材料是石墨烯应用领域中的一个重要研究方向，可分为负载型和增强型。本文主要综述了石墨烯负载金属(单金属、双金属和三金属)/化合物(金属氧化物、金属硫化物和金属氟化物)复合材料近几年的制备方法和应用现状。此外，通过对上述复合材料的总结，得出金属/化合物的颗粒尺寸和形状、分散程度以及石墨烯片层的堆叠等问题会影响性能的结论，并对石墨烯负载金属/化合物复合材料能够在磁性、力学、微波吸收以及导热等领域所具有的应用前景进行展望。     

一种求解一维理想磁流体方程组的保正拉氏方法

拉氏方法在计算流体力学中扮演了一个十分重要的角色，并且十分适合于处理含有强磁场的物理问题，例如 Z 箍缩、托卡马克、惯性约束聚变等等。在这些物理问题中密度和热力学压力总是非负的。然而，运用数值格式对上述方程进行逼近时，得到的近似解并不能总是保持这种正性。为了处理这一问题，首先构建了一种拉氏 HLLD 近似黎曼解，这一近似黎曼解在合适的信号速度下可以保持保正性质。运用这一黎曼解，提出了一种求解一维理想可压缩磁流体方程组的守恒保正拉氏格式。最后，给出一些数值算例来证明方法的保正性。     

哈尔乌素露天煤矿绿色节能矿山建设策略与实践

阐述了国能准能集团哈尔乌素露天煤矿基于黄土高原原始地貌土体构成特性，在肩负煤炭生产保供重任同时，通过制定具有自身特色的绿色矿山建设策略，进行露天煤矿采区生态修复美化的具体实践。其构建起集水土流失控制技术、生态重构技术、复垦绿化标准化作业技术于一体的排土场复垦区治理体系，累计实现复垦绿化土地共683.1 ha,植被盖度提升55%。同时，基于煤矿智能化建设和维护职工职业健康目标出发，通过推进主采系统与生产辅助设备的智能化与无人化，极大地改善了作业人员的工作环境，从源头上隔绝了尘肺病等职业性呼吸系统疾病的发生。在节能减排方面，通过科学管理和精细化管理，使原煤开采吨煤综合能耗控制在3 kg标煤，远低于国家能耗限额先进值，超标准达到国家能耗“双控”要求。     

双功能氮氧化钛-碳涂层提升高容量锂离子电池用SiOx的储锂性能(英文)

非化学计量微米氧化硅(SiO_x)由于其高理论容量和低成本,有望成为锂离子电池石墨负极材料的替代品.然而, SiO_x的实际应用仍然受到其较差的固有导电性和循环过程中明显的体积变化的阻碍.在本工作中,为了同时解决这些问题,我们使用可规模化的溶剂热和热还原方法制备了具有TiO_1-yN_y-C涂层的SiO_x基负极材料(SiO_x@TiON-C).我们通过系统性研究发现, TiO_1-yN_y-C涂层可以适应SiO_x循环过程中大的体积变化且有效提高其导电性.因此, SiO_x@TiON-C负极具有突出的储锂性能.具体而言, SiO_x@TiON-C负极可以在500 mA g^-1的电流密度下循环500圈后仍保持750.2 mA h g^-1的优异可逆容量, 75.1%的初始库仑效率和优异的倍率性能.这项工作为促进下一代锂离子电池微...