发挥电子白板特有功能,让识字教学更显生机——《识字8》第二教时案例分析

《语文课程标准(2011年版)》在低年级学生识字写字教学中明确指出要使学生"喜欢学习汉字,有主动识字、写字的愿望。掌握汉字的基本笔画和常用的偏旁部首,能按笔顺规则用硬笔写字,注意间架结构。初步感受汉字的形体美。学习独立识字"。但是低年级学生活泼好动,注意力持续时间不长,电子白板具有图文并茂、声像俱全、动静结合、视听并举等特点,如果我们能在识字教     

太阳能热发电的研究现状与前景展望

太阳能热利用技术是可再生能源技术领域商业化程度较高、推广应用较为普遍的技术之一，主要包括太阳能热水器、太阳能空调降温、太阳能热发电、太阳房等几个方面。太阳能热发电是太阳能热利用的重要方向，是很有可能引发能源革命的技术成果，也是实现大功率发电、替代化石能源的绿色经济手段之一。     

低放氢压的Ti-Mn基Laves相贮氢合金

研究了Ti/Zr比与Mn/Cr比变化对Ti Mn基Laves相贮氢合金贮氢性能的影响 ,发现随Ti/Zr比降低 ,合金放氢压降低 ,贮氢量略微增加 ,平台坡度变陡 ;随Mn/Cr比降低 ,合金放氢压降低 ,平台区变短 ,但合金的贮氢量变化不大。Ti0 .85Zr0 .15Mn1.6-yCryV0 .32 Fe0 .0 8系列合金当 0 1≤y≤ 0 2时比较适宜作为小型燃料电池的氢源。     

热处理对Nd-Mg-Ni储氢合金结构和性能的影响

采用磁悬浮感应熔炼法制备了Nd-Mg-Ni系储氢合金,重点研究了热处理工艺对合金相组成和电化学性能的影响。采用X射线衍射、扫描电镜和电化学测试系统研究了合金的相结构、显微结构及电化学性能。研究结果表明,Nd0.75Mg0.25Ni2.75Al0.25合金经1173,1273,1373 K退火处理后,随着退火温度的升高,不同相间元素分布更加均匀,Mg元素的浓度差减小,主相Nd2Ni7六方相逐渐增加。电化学P-C-T曲线平台变平缓、平台压降低,电化学容量,倍率性能和荷电保持率有较大提升。对于Nd0.75Mg0.25Ni3.2Al0.1合金,经1373 K,5 h热处理后慢冷较快冷更利于Nd2Ni7相的形成,慢冷试样中Nd2Ni7相可达92.31%,电化学性能更加优异,最大电化学容量为330.1 mA.g-1,循环100周容量保持率为92.2%。     

Enhancement of cerium and hydrogen storage property of a low-cost Ti-V based BCC alloy prepared by commercial ferrovanadium

Based on the analysis of XRD, SEM, P-C-isotherm measurements and absorption kinetics simulation, it was indicated that Ce addition was an effective way to inhibit the formation of C14 Laves phase, improve flatness of the plateau, increase hydrogen diffusion rate and enlarge hydrogen storage capacity. The hydrogenation capacity of Ti27.25Cr28.05V37.25Fe7.45Ce1.0 alloy prepared by commercial ferrovanadium was 3.56 wt.% measured at 298 K. The dehydrogenation capacity was 2.25 wt.% and 2.54 wt.% measured at 343...     

KF掺杂量对MgH2-2LiNH2体系储氢性能影响的研究

采用高能球磨制备了不同摩尔量KF掺杂的MgH2-2LiNH2-xKF(x=0,0.015,0.025,0.050,0.100)储氢材料,采用XRD,DSC-MS和Sieverts方法研究了材料物相与储氢性能。结果表明,KF的掺杂促进了球磨过程中MgH2-2LiNH2向Mg(NH2)2-2LiH的转变,KF掺杂的样品放氢后出现KH的衍射峰。KF的掺杂显著提高了MgH2-2LiNH2材料放氢动力学性能,降低了放氢反应起始温度和激活能,且放氢过程有效抑制了NH3的释放,其中0.05 mol KF掺杂MgH2-2LiNH2体系放氢性能最优。     

富镍镧镍合金催化二苄基甲苯加氢性能研究

采用感应熔炼和球磨方法制备镧镍储氢合金,进一步通过酸处理法原位制备富镍镧镍储氢合金。研究不同条件下制备的镧镍储氢合金催化二苄基甲苯（DBT）加氢性能。在反应温度为280 ℃时,经过4 h后,富镍镧镍储氢合金催化二苄基甲苯的加氢量达到5.34%（质量分数）,20 h后,其加氢量达到理论最大值。富镍镧镍储氢合金具备的高效催化二苄基甲苯加氢活性主要归因于镍的高效催化和镧镍储氢合金可逆吸放氢之间的相互促进作用。     

Study on catalyst for the sodium borohydride hydrolysis

1IntroductionAs ani mportant part in the newenergy sources,hydrogen energy technologies include the H2genera-tion,storage and application.The hydrogen storageis the key step[1].People pay more and more attentionto the chemical hydrogen storage technology due toits high hydrogen storage rate,safe and stable applica-tion.Sodiumborohydride(NaBH4)is a complex hydride.When sodiumborohydrideis used to store hydro-gen,andits hydrogen storage capacityis theoretically about10.8%(mass fraction)[2].Na…     

钛催化氢化铝钠的贮氢性能

通过加入钛系、锆系催化剂以及碳等添加剂可以显著改善配位氢化物的吸放氢动力学性能,加入催化剂可以使配位氢化物的可逆贮氢量达3.1%~4.2%(质量分数)。采用机械合金化法在NaAlH4中加入钛的化合物作为催化剂,在很大程度上改进了其热力学和动力学性能,可逆吸氢量可达4.0%以上,可逆放氢量也能达3.0%以上。并对试样进行了X射线衍射、扫描电镜以及X射线光电子能谱分析,证明了可逆反应的发生,探讨反应的机理。     

Dehydrogenation characteristic of Zr1-xMxCo （M=Hf, Sc） alloy

The intermetallic compound Zr1-xHfxCo and Zr1-xScxCo （x=0, 0.1, 0.2, 0.3） were prepared and their suitability for hydrogen storage was investigated. The alloys show single cubic phase identical with ZrCo by X-ray diffraction. Pressure- composition-temperature（PCT） measurement results show that the equilibrium dehydrogenation pressure of Zr1-xHfxCo alloy increases obviously with increasing Hf content while it changes little with increasing Sc content for Zr1-xScxCo alloy. The dehydrogenation temperatures for supplying 100 kPa hydrogen are about 673,627, and 650 K for ZrCo, Zr0.7Hf0.3Co and Zr0,7Sc0.3Co alloy, respectively. Thermodynamics calculation results indicate that dehydrogenation AH for Zr1-xHfxCo alloy decreases with increasing Hf content but increases with increasing Sc content for Zr1-xScxCo alloy, which are coincident with their dehydrogenation property. The maximal hydrogen storage capacity of both Zr1-xHfxCo and Zr1-xScxCo alloy at room temperature are high enough.