Preparation and properties of the SmOx/Rh(100) model surface

The preparation of SmOx/Rh(100) and CO adsorption on this model surface have been investigated with Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption spectroscopy (TDS). The oxygen adsorption on the SmRh alloy surface leads to the aggregation of Sm on the surface. The thermal treatment of this oxidized surface induces the further agglomeration of SmOx on the Rh(100) surface. Compared with CO TDS on the clean Rh(100) surface, three additional CO desorption peaks can be observed at 176, 331 and 600 K on the SmOx/Rh(100) surface. The CO desorption peak at 176 K may originate from CO adsorbed on SmOx islands, while the appearance of the CO adsorption peaks at 331 and 600 K, depending on the oxidation state of Sm, is attributed to CO species located at the interface of SmOx/Rh(100).     

Preparation and properties of the SmOx/Rh(100) model surface

The preparation of SmO_x/Rh(100) and CO adsorption on this model surface have been investigated with Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption spectroscopy (TDS). The oxygen adsorption on the SmRh alloy surface leads to the aggregation of Sm on the surface. The thermal treatment of this oxidized surface induces the further agglomeration of SmO_x on the Rh(100) surface. Compared with CO TDS on the clean Rh(100) surface, three additional CO desorption peaks can be observed at 176, 331 and 600 K on the SmO_x/Rh(100) surface. The CO desorption peak at 176 K may originate from CO adsorbed on SmO_x islands, while the appearance of the CO adsorption peaks at 331 and 600 K, depending on the oxidation state of Sm, is attributed to CO species located at the interface of SmO_x/Rh(100).     

正己烷在CaCO3(100)面吸附的第一性原理研究

致密油在储层多孔介质中的吸附研究多以定量的实验研究为主,定性的机理研究较少。以正己烷为对象,从原子分子层面定性研究其在碳酸钙表面的吸附能力,为解释致密油在储层岩石基质上的吸附性提供了有力依据。采用基于密度泛函理论的第一性原理方法,计算了C_6H_(14)分子在CaCO_3(100)面的吸附能,对比分析了吸附前后的物理结构和电子态密度。结果表明:C_6H_(14)分子在B11位吸附最稳定,吸附能为-0.782 4 eV,吸附后键长键角变化率均小于1%,是一种弱化学吸附。不同吸附位的能量差值很小,仅为0.017 8 e V,C_6H_(14)分子容易在CaCO_3表面发生稳定流动。吸附后,C_6H_(14)分子的电子态密度向低能量区域整体偏移约3.1 e V,而CaCO_3(100)面的电子态密度曲线基本重合,吸附作用对C_6H_(14)分子的电子结构影响显著,对CaCO_3(100)面电子结构影响甚微。     

Equilibrium geometric structure and electronic properties of Cl and H2O co-adsorption on Fe (100) surface

Based on the first principles density functional theory, the equilibrium geometric structure and surface electronic properties of Cl and H₂O co-adsorption on the Fe (100) surface are investigated. The results indicate that the optimal adsorption site for Cl and H₂O co-adsorption on the Fe (100) surface is the location of Cl at the bridge site and H₂O at the top site. Compared with the Fe (100)/H₂O adsorption system, remarkable changes in geometric structure and electronic properties occur, owing to the presence of Cl in the Fe (100)/(H₂O+Cl) adsorption system. The analysis of equilibrium geometric structure and surface electronic properties shows that the presence of Cl in the Fe (100)/(H₂O+Cl) adsorption system unstablizes the Fe surface, making it easy to lose electrons. Supported by the National Natural Science Foundation of China (Grant Nos. 50675112, 50721004) and Research Fund for the Doctoral Program of Higher Education (Grant No. 20070003103)     

Pt_6/BaO(100)界面性质的第一性原理研究

利用基于密度泛函理论的第一性原理方法研究了Pt6/BaO(100)界面的性质.对界面几何结构和电子结构的分析表明,铂原子与表面氧原子之间有很强的共价相互作用,这种相互作用使Pt6/BaO(100)界面非常稳定,与实验结果的分析相一致.     

FexPt100-x取向薄膜的结构与磁性

用电子束沉积法在加热到100℃的MgO（001）基板上生长了50nm厚的FexPt100-x取向薄膜,原子比成分范围为x=[10,85].在500℃进行保温2h的原位热处理后,分析样品的结构及沿面内和垂直于薄膜方向施加磁场的磁性行为.结果表明,随着x的增加,易磁化轴的方向在沿平行于膜面方向和垂直于膜面方向之间反复变化,取决于内秉的磁晶各向异性与外秉的形状各向异性之间的竞争.当x=60时,由于薄膜发生不完全的A1→L10相转变,形成了A1软磁相与L10硬磁相的复合体,样品沿平行和垂直于膜面方向磁化的矫顽力都达到5kOe（1Oe=79.5775Am-1）以上.沿膜面方向磁化时,矫顽力高于软磁相的磁晶各向异性场,并且正负向磁化的剩余磁化强度明显不相等.采用三磁畴软磁相模型,结合硬磁/软磁交换耦合作用,对此进行了解释.这种硬磁/软磁复合材料适合于用来制作磁力显微镜的各向同性高矫顽力探针.     

CO吸附于PtRu合金(100)面上的DFT理论研究

采用DFT方法对CO吸附在PtRu(100)表面的吸附行为进行系统性的研究,分析了键参数及电子结构．结果表明Ru的加入确实能削弱CO在合金上的吸附并且活化CO分子．当Ru的含量达50％时,PtRu催化剂抗CO中毒能力最强．另外CO分子在合金表面的吸附还和其吸附位及表面原子排布有关,CO吸附在Pt上较吸附于Ru上更强,吸附位周围分布Ru较分布Pt更促进CO分子的活化．     

Sm0.5Eu0.5(Hacac)2HAA三元配合物的合成及其光致发光

合成了稀土配合物Sm(Hacac)2HAA和Sm0.5Eu0.5(Hacac)2HAA并通过红外光谱、元素分析确定了其组成,探讨了它们的光谱特征.结果表明:Sm(Hacac)2HAA和Sm0.5Eu0.5Hacac)2HAA的均发出Sm3+的特征光谱,发射峰在647 nm;Eu3+的掺入提高了配合物Sm0.5Eu0.5...     

Electronic structures of the oxygenated diamond （100） surfaces

Diamond is a kind of nonmetal material with unique physical and chemical properties. It is potentially useful to various applications in electronics, such as electron emitters, Schottky diodes[1-3]. The diamond films ob- tained by chemical vapor depositio…     

Synchrotron radiation photoemission study on growth of gadolinium film over Ni(110) surface

The growth of Gd film on Ni (110) surface was studied by synchrotron radiation photoemission spectroscopy and XPS techniques. It is revealed that in the coverage range of 0–0.22 nm Gd4f core level showed a single-peak structure, therefore Gd film grows over Ni(110) in the layer-by-layer mode. However, when Gd coverage was larger than 0.22 nm the Gd4f peak turned gradually into double-peak and a double-peak structure with 2.3 eV separation was formed at 1.51 nm, meanwhile similar phenomenon was observed in the Gd4d XPS spectra. It is suggested that the double-peak structure of Gd4f was derived from the growth of Gd film in cluster mode and the Gd atomic clusters may exhibit different electronic states from Gd metal owing to their special structures. The Gd4f double-peak e-volved into a single-peak on annealing at 600 K, implying that Gd clusters are thermodynamically unstable.     

硝酸钐对白术一些生理生化指标的影响

通过萌发试验和盆栽试验,研究了不同浓度的硝酸钐溶液对白术的种子活力、丙二醛(MDA)含量、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性、叶绿素含量、光合速率等一系列生理生化指标的影响.结果表明,用20、30 mg.L-1的硝酸钐溶液浸种,使白术种子的发芽率和活力指数增加,白术幼苗的MDA含量、SOD和POD活性降低;用100 mg.L-1以下质量浓度的硝酸钐溶液喷施白术植株叶面,使其叶绿素含量增加,MDA含量减少,POD、SOD活性下降;当硝酸钐质量浓度达到300 mg.L-1时,白术叶片的POD、SOD活性和MDA含量增加.     

PET/丙烯腈接枝膜阻氧性能的研究

对聚对苯二甲酸乙二醇酯(PET)/丙烯腈（AN）接枝膜的阻氧性能进行了研究。结果表明，随着接枝率的增加透氧率（P）下降，P从4.25mL·mm/(m²·d)下降到2.49mL·mm/(m²·d)。接枝率相同时，低温下得到的接枝膜的阻氧性能更好。在PET膜表面接枝AN前后，其结晶度均为36%左右。聚合温度为90℃时，接枝链颗粒小、分布均匀；聚合温度为95℃时，接枝链颗粒大、分布不均匀。此外，高温和高湿度的环境中，接枝膜的阻氧性能均好于空白膜。     

富勒烯C_(100)及其衍生物C_(100)X_4的理论研究

在混合密度泛函B3LYP理论下,用6-31G*基函数对富勒烯C100分子的6个能量较低异构体及基于能量最低异构体衍生物C100X4(X=H,F,Cl,Br)的几何结构、电子结构进行了研究.计算结果表明:D2C100是最稳定的,C100X4(X=H,F,Cl)的形成均为放热反应.振动频率计算表明,C100X4(X=H,F,Cl,Br)均是势能面上的稳定驻点,C100F4在所研究的簇分子中是较为稳定的,应该能够合成出来.     

Sm取代Tb(Dy)对RE-TM薄膜磁光性能的影响

采用磁控溅射复合靶的方法制备了SmTbCo/Cr和SmDyCo/Cr非晶垂直磁化膜,分析了Sm含量对SmTbCo/Cr和SmDyCo/Cr薄膜磁光性能的影响.结果表明:随着Sm含量的增加,(SmxTb1-x)31Co69和(SmxDy1-x)36Co64薄膜的剩余磁化强度Ms、克尔旋转角θk和反射系数R增加,而Hc随之减少;Sm含量为29%~30%时,Hc×Ms最大.     

Ca(Sm0.5Nb0.5)O3介质陶瓷的微波烧结

通过改变微波烧结温度和保温时间,优化Ca( Sm0.5 Nb0.5) O3 (CSN)陶瓷的微波烧结工艺,用X线衍射仪(XRD)、扫描电镜(SEM)和微波网络分析仪等对试样进行表征.从相组成、显微结构及微波介电性能等方面对微波烧结试样与常规烧结试样进行对比分析.结果表明:微波烧结可大幅降低CSN的烧结温度,促进试样的致密化,其物相组成和传统烧结试样无明显差别;微波烧结还可以改善CSN陶瓷的微波介电性能,在1 375℃微波烧结30 min可获得优异的微波介电性能,介电常数(εr)=20.08,品质因数(Q×f)=37.03 THz,谐振频率温度系数(Tf)=-10.2×10-6℃-1.     

红色荧光粉KGd(WO4)2:Sm3+的制备及发光性能

采用高温固相法合成KGd(WO4)2:Sm3+荧光粉,样品在近紫外区404nm光激发下发射出Sm3+的特征光谱.通过X射线粉末衍射、荧光光谱等对其进行了表征,并分析了其发光特性,结果表明:在KGd(WO4)2:Sm3+中Sm3+离子最佳的掺杂量为5%(摩尔分数);烧结温度为1 000℃、助熔剂H3BO3的浓度为2%(摩尔分数)时,样品的发光强度最强.     

纳米(CeO_2)_(0.86)(Sm_2O_3)_(0.14)的形貌控制与表征

以Ce(NO3)3·6H2O和(NH4)2CO3为沉淀源,搀杂稀土氧化物Sm2O2,利用柠檬酸作为络合剂和分散剂,制备出纳米(CeO2)0.86(Sm2O3)0.14.并采用TEM、XRD等方法对其热分解所得纳米(CeO2)0.86(Sm2O3)0.14的形貌及结晶性等进行了表征.结果表明:随着柠檬酸加入量的增加,焙烧生成的纳米(CeO2)0.86 (Sm2O3)0.14颗粒的形貌从纳米线向类球形颗粒变化,所得(CeO2)0.86(Sm2O3)0.14为立方萤石结构,且随焙烧温度的提高,晶化程度增大.     

共聚醚P（E－CO－T）及其与N－100固化后的聚醚聚脲聚氨酯的热分解性能

采用热失重分析法考察了端羟基环氧乙烷／四氢呋喃共聚醚及其与Ｎ－１００固化后的聚醚聚脲聚氨酯胶片的热分解性能．讨论了增塑剂（邻苯二甲酸二丁酯、硝化甘油和１，２，４－丁三醇三硝酸酯混合物）、固体填料（铝粉、高氨酸铵和奥克托今）以及助剂（碳黑、硝化纤维素和健合剂）对聚醚聚脲聚氨酯胶片热分解性能的影响．结果表明共聚醚在惰性环境中于２００℃左右开始分解．抗氧剂（２，６－二叔丁基－４－甲基酚）能有效提高共聚醚的分解稳定性；含增塑剂、固体填料和助剂的聚氨酯胶片的热分解性能以及抗氧剂的稳定效果因增塑剂、填料和助剂的不同而有较大差别．