Hydrogenation properties of mechanically milled Mg2Nio.8Cr0.2-CoO/Al2O3 composites

Mg2Ni0.8Cr0.2-x wt.% CoO/Al2O3 (x=0.5, 1, 2 and 3) composites were prepared by mechanically milling sintered Mg2Ni0.8Cr0.2 alloy and CoO/Al2O3 compound for 45 h. The addition of CoO/Al2O3 compound resulted in the good kinetics properties of hydriding/dehydriding reaction of the composites. The composite with 1.0 wt.% CoO/Al2O3 catalyst could reach the maximum hydrogen absorption capacity (2.9 wt.%) within 5 min at 393 K under H2 pressure of 4 MPa, and can desorb rapidly at 493 K. The decomposition and synthesis of hydrogen molecule on Mg2Ni0.8Cr0.2 alloy surface was promoted by addition of CoO/Al2O3 catalyst. In addition, the formation of metallic Ni particles, strain and defects during the ball milling process also resulted in the improved hydrogenation performance of Mg2Ni-based alloys.     

Hydrogenation properties of mechanically milled Mg2Ni0.8Cr0.2-CoO／Al2O3 composites

INTRODUCTION Mg-based alloys are considered as potentialcandidates for hydrogen storage materials because oftheir large hydrogen capacity (Reilly and Wiswall,1968; Pedersen and Larsen, 1993). However, asMg-based alloys desorb hydrogen at temperatureshigher than 600 K, they are not applicable to practicaluse. Many researches have studied to improve hy-driding/dehydriding kinetics and to lower the workingtemperature (Wang et al., 2002; Tsushio et al., 1998;Spassov and K?ster, 1998; Orim…     

Study on microstructures and properties of several kinds of hot working die steel

１ＩｎｔｒｏｄｕｃｔｉｏｎＡｌｏｎｇｗｉｔｈｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｍａｃｈｉｎｅｍａｎｕｆａｃｔｕｒｅ,ｔｈｅｕｔｉｌｉｚａｔｉｏｎｏｆｔｈｅｄｉｅｓｂｅｃｏｍｅｓｗｉｄｅｒｔｈａｎｅｖｅｒｂｅｆｏｒｅ．Ａｓｔｈｅｆｏｒｍｉｎｇｔｏｏｌｆｏ...     

Influence of Heat Treatment on Microstructure and Sliding Wear Behavior of Fe-Al/WC Composite Coatings

Researchershavebecomeincreasinglyinterestedinironaluminideintermetallics (includingFe3AlandFeAl)since 1970sinviewofthecombinationoflowcost,lowerdensity ,remarkableresistancetoerosion ,sulfidizingandoxidizingathightemperature .However ,industrialap plicationofthesealloyshasbeenverylimitedduetotheirpoorductilityandfracturetoughnessatroomtemperatureaswellastheirdifficultyinshaping[1] .Somestudieshaveindicatedthatcoatingstructuralmaterialswithironaluminidesbyusingthermalsprayingwillnotonlysolveth…     

黑豆皮红色素的提取工艺及稳定性研究

本实验首次采用超声波辅助提取黑豆皮红色素,应用正交法优化黑豆中红色素提取的工艺条件及研究超声波对黑豆中红色素提取的影响。结果表明,最佳提取工艺条件：提取液为9%盐酸,料液比1：25（g/mL）,温度为70℃,提取时间为2h,超声波功率为100%。黑豆皮红色素在维生素C、NaCl、柠檬酸等食品添加剂存在下稳定性好;红色素耐还原性能力较强,对光和氧化剂不稳定;Fe3＋、Zn2＋、Cu2＋等金属离子对红色素的稳定性影响较大,Ca2＋、Al3＋对红色素稳定性影响较小。     

Fe2O3 as indicator of heavy metal enrichment in Zhujiang(Pearl River) estuary sediments

A part of the heavy metals in estuary and coastal zone occurs naturally in the environment; the other part is due to human activity; so the directly measured concentration of heavy metal does not automatically indicate anthropogenic enrichment. Fe2O3 was used in this study as conservative tracer to distinguish natural components from anthropogenic components of heavy metal sediment concentration in the Zhujiang estuary. Compared with clay and Al2O3, Fe2O3 is more suitable as reference element. The final results showed that two zones in the Zhujiang estuary were seriously contaminated by heavy metals. One nearby the Humen mouth; the other around the west coast of the estuary. The horizontal distribution of heavy metals indicates that Zn, Ni and Cu have wider contaminating areas than TiO2, V and Cr in the estuary.     

α型籽晶对氧化铝基薄膜低温生长及力学性能的影响

采用Al+α-Al2O3复合材料及Al100-xCrx(x=10,20,30)合金作为靶材,用反应磁控溅射将α型籽晶引入氧化铝基薄膜中,研究了籽晶对氧化铝基薄膜的元素比例、相组成、结构特征、表面形貌及纳米硬度的影响.结果显示,在550℃时溅射Al+α-Al2O3复合靶所得的薄膜由单相的α-Al2O3组成,而在同一温度下采用Al70Cr30合金靶所制得的薄膜中检测到α-(Al0.7Cr0.3)2O3固溶体.纯α-Al2O3薄膜及α-(Al0.7Cr0.3)2O3固溶体薄膜的纳米硬度分别达到~23.5GPa和~28.5GPa.     

十七省市奶粉中26种矿质元素的测定

作者收集了国内17个省市(自治区)的18个乳品生产厂家的全脂奶粉。用六种方法测定奶粉中的铁、锰、锌、钴、钼、铬、镍、矾、锡、氟、硒、硅、砷、钠、钾钙、磷、镁、铝、硼、钴、镉、钡、铅、锶和汞等26种矿质元素的含量。并对所获得的数据进行了初步的分析与讨论。     

Fe salts as catalyst for the wet oxidation of o-chlorophenol

INTRODUCTION Chlorophenols (CPs) are chemicals widely used in industry to manufacture insecticides, herbicides, fungicides, biocides, and dye, are also found in the effluent of the pulp and paper mill industry, and are mainly man-made compounds, and have been recog-nized as organic pollutants of air, groundwater, soil and sediments. They are carcinogenic and stable in water. Most chlorophenols are listed as priority pol-lutants by the US Environmental Protection Agency (1988) due to th…     

青海枸杞子中矿质元素的测定

采用HNO3/H2O2湿法微波消解制样,利用全谱直读电感耦合等离子原子发射光谱法(ICP-OES),全面详细地分析测定了青海红果枸杞子中的矿质元素,共检出K、Na、S、P、Mg、Ca、Si、Al、Fe、Zn、B、Cu、Mn、Se、Pb、Sr、Ti、Ba、Cr等19种矿质元素。分析结果相对标准偏差RSD值在2.41%~10.1%之间,其中10种元素在5%以内。枸杞子中所含人体常量元素K、Na、S、P、Mg、Ca等的质量分数分别为0.96%、0.25%、0.22%、0.19%、0.080%和0.077%;微量元素Fe、Zn、B、Cu、Mn、Se、Sr、Cr等的含量分别为5.97、1.34、1.09、0.88、0.57、0.52、0.33、0.055 mg/100g。此外,还含有9.35 mg/100g的Al和0.45 mg/100g的Pb。     

静电纺丝法制备Co0.5Ni0.5Fe2O4纳米纤维及影响因素研究

采用静电纺丝技术制备了PVP/[Co(NO3)3+Ni(CH3COO)2+Fe(NO3)3]复合纤维,通过X射线衍射(XRD)、扫描电镜(SEM)和振动样品磁强计(VSM)对复合纤维及其焙烧产物进行了表征,较为系统地考察了制备参数,如PVP含量、醇/水比例、电场强度以及无机盐含量对复合纤维形貌和直径的影响,获得了最佳制备条件。将所得复合纤维在550℃焙烧2h可以制得单相尖晶石结构的晶态Co0.5Ni0.5Fe2O4纳米纤维,其平均直径约为80nm,在室温下具有良好的磁性,比饱和磁化强度和矫顽力分别为52.3A.m2/kg和81.0kA/m。     

核/双壳医用磁性微球的研制

用共沉淀法制备Fe3O4磁性粒子,选用聚乙二醇和琼脂制备核/双壳医用磁性微球.最佳工艺条件为:Fe3+/Fe2+之比在1.70～1.75;沉淀剂25%NH3.H2O过量20～30%,在温度35℃,pH值11,反应时间为1h;琼脂的包覆最佳温度为50℃,pH值为9,时间1h;聚乙二醇包裹最佳温度为55℃,pH值为4,时间1h,可以通过调节搅拌速度和超声波分散时间控制Fe3O4粒子的尺度,实验确定包覆剂用量.并用透射电镜、分光光度计、古埃磁天平等进行了初步表征.     

纳米氧化铝粉体制备及红外吸收特性研究

通过溶胶-凝胶法制备出不同晶型和相应颗粒尺寸的纳米氧化铝粉体;通过XRD分析及TEM表征,分析勃姆石凝胶-经干燥烧结后的氧化铝晶型相变及相应颗粒尺寸分布变化,800℃至1050℃γ-Al2O3向θ-Al2O3相变过程中颗粒尺寸变化不大,到完全相变为α-Al2O3时,颗粒尺寸急剧增大,并有大颗粒形成;同时对不同晶型和对应的颗粒尺寸纳米氧化铝粉体样品的红外吸收性能进行了研究,结果表明:带边吸收的蓝移、红移主要由晶型和量子尺寸效应共同作用,但晶型起主要作用。     

钼表面（Mo,W）Si2-Si3N4复合涂层的低温氧化行为研究

采用包渗法在钼表面原位制备了（Mo,W）Si2-Si3N4复合涂层,考察了其在大气中于500℃和600℃等温循环的氧化性能,利用XRD和SEM等研究了其组织形貌.结果表明：（Mo,W） Si2-Si3N4涂层具有良好的低温抗氧化性,其在空气中500℃和600℃氧化480 h的氧化速率分别为0.0145 g/（m2·h）和0.0191g/ （m2·h）,归因于涂层氧化表面形成了致密的SiO2膜.     

Al对AB5贮氢电极高温性能的影响

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　ＡＢ5 ｔｙｐｅｈｙｄｒｏｇｅｎｓｔｏｒａｇｅａｌｌｏｙｓｈａｖｅｂｅｅｎｉｎｔｅｎ ｓｉｖｅｌｙｉｎｖｅｓｔｉｇａｔｅｄｓｉｎｃｅｔｈｅｆｉｒｓｔｕｓｅａｓａｎｅｌｅｃｔｒｏｄｅｒｅｐｏｒｔｅｄｂｙＪｕｓｔｉｉｎ 1973[1] .ＴｈｅｃｏｍｍｅｒｃｉａｌＡＢ5ｅｌｅｃｔｒｏｄｅｓｕｓｅｍｉｓｃｈｍｅｔａｌ,ａｌｏｗｃｏｓｔｍｉｘｔｕｒｅｏｆｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓ ,ａｓａｓｕｂｓｔｉｔｕｔｅｆｏｒＬａ ,ｗｈｉｌｅｔｈｅＢ5ｃｏｍｐｏｎｅｎｔｒｅｍａｉｎｓｐｒｉｍａｒ…     

甲苯分散介质中外消旋BINOL的快速氧化偶合

对以甲苯为分散介质,Fe2O3.6H2O和空气中的氧气为氧化剂,Al2O3为催化剂,催化氧化偶联2-萘酚合成外消旋BINOL的反应条件进行了研究.研究结果显示,在60-90℃下反应10 min,m(2-萘酚):m(Fe2O3.6H2O):m(Al2O3)=1:2.5:1.4时,BINOL收率达82%.     

退火温度对NZFO铁氧体薄膜磁性能的影响(英文)

采用化学溶液沉积法在Si(001)衬底上制备Ni0.7Zn0.3Fe2O4铁氧体薄膜,XRD谱表明样品具有单相的尖晶石结构;扫描电子显微镜结果表明样品平均颗粒尺寸随着退火温度的上升从10 nm增加到32 nm。NZFO铁氧体薄膜磁性能与退火温度有强烈的依赖关系,薄膜的矫顽力从退火温度为500℃时的25 Oe增加到900℃时的80 Oe,饱和磁化强度也由146emu/cm3增加到283 emu/cm3,这对于现代电子器件微型化有着非常重要的意义。     

冷轧退火Fe3(Al，Cr，Zr)金属间化合物的室温环境脆性及择优取向

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　Ｆｅ3Ａｌｂａｓｅｄａｌｌｏｙｓｅｘｈｉｂｉｔｈｉｇｈｏｘｉｄａｔｉｏｎｒｅｓｉｓｔａｎｃｅ ,ｅｘｃｅｌｌｅｎｔｓｕｌｐｈｉｄａｔｉｏｎｒｅｓｉｓｔａｎｃｅａｎｄｌｏｗｃｏｓｔｏｆａｌｌｏｙｃｏｎｓｔｉｔｕｅｎｔｓ.Ｈｏｗｅｖｅｒ ,ｔｈｅｓｅａｌｌｏｙｓｈａｖｅｎｏｔ ｙｅｔｆｏｕｎｄｗｉｄｅｓｐｒｅａｄａｐｐｌｉｃａｔｉｏｎｆｏｒｔｈｅｉｒｅｎｖｉｒｏｎｍｅｎｔａｌｅｍｂｒｉｔｔｌｅｍｅｎｔ[1～ 3] .Ｔｈｅｔｅｎｓｉｌｅｐｒｏｐｅｒｔｉｅｓａｎｄｅｎｖｉ ｒｏｎｍｅｎｔ…     

10种金属氧化物对氯酸钾热分解制氧催化效果的研究

加热KClO3分解制氧常使用MnO2作催化剂。实验发现：CaO，A12O3，CuO，FeO3，TiO2，Nd2O3，PdO2，V2O5，Cr2O39种金属氧化物及无机盐MnSO4，FeCl2，FeCl3，CoCl2，ZnCl2等亦有较好的催化效果，在试剂用量、产氧量、反应速度和控制副反应等方面具有明显的优点。     

无机高分子混凝剂聚硅硫酸盐的制备

无机高分子絮凝剂是城市用水和工业废水处理的有效药剂。在研究聚合硫酸铁(PFS)合成工艺的基础上,设计出一套合成无机高分子混凝剂聚硅硫酸铁(PSPFS)和聚硅硫酸铝铁(PSAFS)的方法。采用正交试验法,通过模拟浊水的混凝试验,确定Fe/Si摩尔比、Na2SiO3.9H2O溶液聚合时间、反应时间、反应温度和Al/Si摩尔比等最佳参数。