H_2分子在Ni（100）、（110）、（111）单晶表面吸附研究

本文来用改进模型势方法，计算了Ｈ２分子在Ｎｉ（１０Ｏ）、（１１０）、（１１１）单晶表面解离吸附的反应途径与位能面．通过对比研究，讨论了氢分子在镍三种单晶表面解离吸附的反应途径和位能面的一般规律与趋势．     

分子和表面吸附系统振动频率的理论计算研究

用ＡＳＥＤ－ＭＯ方法计算分子及表面吸附系统在平衡点附近的总能量．用二次多项式、三次多项式和两种形式Ｍｏｒｓｅ势能展开式模拟能量变化以求出力常数，从而得到振动频率．计算结果表明：在势能展开式中引入非对称项是振动频率结果得到较大改善的关键．本文进一步讨论了用Ｍｏｒｓｅ势、ＡＳＥＤ－ＭＯ方法计算的Ｃ２Ｈ２－Ｓｉ（１００）、Ｃ２Ｈ４－Ｓｉ（１００）吸附系统的振动频率，计算结果与实验结果符合得很好，从而支持了ＨＲＥＥＬＳ提出的上述分子在Ｓｉ（１００）－２×１表面的吸附结构．     

H在DBA表面上的化学吸附能计算

采用Ｅｉｎｓｔｅｉｎ－Ｓｃｈｒｉｆｆｅｒ化学吸附理论和复能积分技术在平均了矩阵近似（ＡＴＡ）下计算了氢原子在无序二元合全（ＤＢＡ）ＣｕｘＡｕ１－ｘ，，ＣｕｘＰｔ１－ｘ，ＮｉｘＡｕ１－ｘ和ＮｉｘＰｔ１－ｘ表面上的化学吸附能．计算结果表明：（１）Ｈ／ＣｕｘＡｕ１－ｘ和Ｈ／ＮｉｘＡｕ１－ｘ系统的化学吸附能分别随着ＣＵ浓度和Ｎｉ浓度的增加而减小；（２）对于Ｈ／ＣｕｘＰｔ１－ｘ系统，在Ｘ＝０．４处化学吸附最稳定；（３）Ｈ在ＮｉｘＰｔ１－ｘ表面上的化学吸附在Ｘ＝０．２处是不稳定．     

高分散度催化剂Pt／Mg（Al）O与Pt／Al2O3化学吸附H2,CO和CO2的…

比较了制法完全机同产有相近铂分散度的催化剂Ｐｔ／Ｍｇ（Ａｌ）Ｏ与Ｐｔ／Ａｌ２Ｏ３的性质。由于Ｈ２和ＣＯ的化学吸附以及随之使用的红外光谱微量热计测定了它们的Ｐｔ的性质，并由ＣＯ２的程序升温脱附（ＴＰＤ）技术测定了Ｍｇ（Ａｌ）Ｏ的碱性在点的性质。在沉积了Ｐｔ颗粒后Ｍｇ（Ａｌ）Ｏ的表面生降低。与Ｐｔ／Ａｌ２Ｏ３相比，Ｐｔ／Ｍｇ（Ａｌ）Ｏ在１９９０－１９３０ｃｍ＾－出现了一个新的Ｃ上吸附波带，它被认为是Ｃ     

三元体系La（ClO4）3.3H2O—18C6—CH3COCH3（25℃）的研究

为了探针稀土高氯酸盐与冠醚１８Ｃ６在不同溶剂中相平衡行为规律性，采用半微量相平衡方法研究了三元体系Ｌａ（ＣｌＯ４）３．３Ｈ２Ｏ－１８Ｃ６－ＣＨ３ＣＯＣＨ３在２５℃时的相平衡行为，测定了饱和液相的折光率，并绘制了相应的相图和饱和液相的折光率曲线，结果表明，饱和溶液的折光率曲线与相图中的溶解度曲线相吻合，体系形成了两种化学计量的配合物：Ｌａ（ＣｌＯ４）３．１８Ｃ６．３Ｈ２Ｏ．２ＣＨ３ＣＯＣＨ３和Ｌａ（     

W（VI）,Mo（VI）在D290大孔阴离子交换树脂相内的交换反应

研究了ＷＯ＾２－４，ＭｏＯ＾２－４，Ｈ２Ｗ１２Ｏ＾６－４０和Ｍｏ８Ｏ＾４－２６在Ｄ２９０树脂内的交换性和扩散常数Ｂ，内扩散系数Ｄ，阻滞时间τｄ半衰期ｔ１／２及活化能△Ｅ，提出了一种新的Ｗ（ＶＩ），Ｍｏ（ＶＩ）分离方法。     

负载贵金属的层柱分子筛比表面积研究

采用两种矿产钙质蒙脱土为原料制备了两种层柱分子筛（Ａｌ－ＣＬＭ和Ａｌ－ＣＬＢ）。首先考察了焙烧温度对其比表面积的影响，结果发现在３００～５００℃范围内，随着焙烧温度的提高，层柱分子筛的比表面积逐渐增大，６００℃以后比表面积迅速下降；对负载贵金属Ｐｔ或Ｐｄ后其比表面积变化情况的研究表明，不论是Ａｌ－ＣＬＭ还是Ａｌ－ＣＬＢ，负载金属后比表面积均下降，且负载Ｐｔ后比表面积下降均比负载Ｐｄ后比表面积下降得多；在Ｐｔ／Ａｌ－ＣＬＭ比表面积因浸渍液的不同而引起的比表面积变化的研究中，发现用酸性较强的浸渍液（Ｈ２ＰｔＣｌ６·６Ｈ２Ｏ）比用酸性较弱的浸渍液（Ｐｔ（ＮＨ３）４Ｃｌ２）所引起的比表面积下降得多，最后在Ｐｔ（Ｐｄ）／Ａｌ－ＣＬＭ和Ｐｔ（Ｐｄ）／Ａｌ－ＣＬＢ的苯加氢反应中发现苯转化率随着比表面积的增大而上升。     

C_3AH_6－Al（OH）_3－Ca（OH）_2－CaX_2（X＝F，Cl）系

研究了氟铝酸钙（Ｃ１１Ａ７ＣａＦ２）和氯铝酸钙（Ｃ１１Ａ７ＣａＣｌ２）两种矿物在原材料经水热预处理的条件下，即在Ｃ３ＡＨ６－Ａｌ（ＯＨ）３－Ｃａ（ＯＨ２）－ＣａＸ２（ｘ＝Ｆ，Ｃｌ）系统中的形成规律，研究结果表明，原料经水热预处理以后，Ｃ１１Ａ７ＣａＸ２（ｘ＝Ｆ，Ｃｌ）的形成温度较ＣａＣＯ３－Ａｌ２Ｏ３－ＣａＸ２（Ｘ＝Ｆ，Ｃｌ）系统大大提前，而矿物的水化特性基本上没有区别。     

铜（Ⅱ）盐催化卤代苯酚聚合反应影响因素的研究（Ⅱ）

详细研究了影响多相聚合反应铜（Ⅱ）盐催化卤代苯酚聚合的各种因素．卤代苯酚发生聚合反应的活性次序为：２，４，６－三溴苯酚＞２，４，６－三溴间甲苯酚＞２，４，６－三氯苯酚．用甲醇钠作为碱，反应体系中少量水的存在有利于聚合反应，而过量水则不利于聚合反应．分离出的铜（Ⅱ）盐中，当ＣｕＣｌ２·２Ｈ２Ｏ／ＣＨ３ＯＮａ摩尔比为０．５时对聚合反应有最大的催化活性．并提出了铜（Ⅱ）盐催化的由铜（Ⅱ）－酚氧配合物中间体生成聚合物的单电子转移历程．     

微乳液介质—1—（2—吡啶偶氮）—2—萘酚光度法测定水中微量铜

以Ｃ６Ｈ６／Ｈ２Ｏ／ＴｒｉｔｏｎＸ－１００／Ｃ２Ｈ５ＯＨ构成的非离子型微乳液为介质，进行了ＰＡＮ－Ｃｕ（Ⅱ）分光光度研究。选择５５４ｎｍ为测定波长，测得表观摩尔吸光系数ε为３．９７×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１。本法将ＰＡＮ溶解在微乳液中，可直接测定水中铜（Ⅱ），省去原萃取光度法中的萃取过程，操作简单，配合使用酒石酸钾钠可准测定锻中的向量铜。     

The Theoretical Study of O_2 Adsorption on NiTi (100) and (110) Surfaces

1　IntroductionNiTishapememoryalloyhaswidelybeenusedinmanyfieldsduetoitsexcellentmechanicalproperties ,uniqueshapememoryeffectandsuperelasticity .In 1970’s ,thegoodbiocompatibilityofNiTialloywasdiscoveredanditwasfurtherusedforvariousbiomedicalapplica tions ,suchasorthopaedicsurgery ,cardiovascularandgas trointestinalsurgery[1-4] .Thehighmechanicalpropertiesandbiocompatibilityofthebiomedicalmaterialsarenec essaryfortheirefficientuseinhumanbody .Thecorrosionresistanceofthealloyandthetoxicityo…     

H2在Pt（111）表面吸附及电催化的密度泛函理论

Pt是燃料电池的重要电催化剂,为研究H2在Pt表面的吸附和氧化行为,采用密度泛函理论,通过构造表面层模型方法,对H2分子在金属态和电极Pt(111)表面Top、Bridge和Hollow三种吸附位进行研究。 H2在Pt(111)表面Hollow位吸附能最大,Top位吸附能最小;电极表面吸附能远大于金属态表面吸附能。吸附过程中H—H键被拉长,吸附后H—H键振动频率比自由分子振动频率减少,产生明显红移。电吸附过程中电子由H2分子向电极Pt(111)表面进行了不同程度的转移。计算结果与实验结果十分相近,从理论上解释了H2在电极Pt表面的电吸附和电催化机理。     

Study on hydrogen atom adsorption and diffusion properties on Mg (0001) surface

Hydrogen atom adsorption and diffusion properties on clean and vacancy defective Mg (0001) surface have been investigated systematically by using a first-principles calculations method based on the density functional theory. The calculation results of adsorption energy and diffusion energy barrier show that hydrogen atom is apt to be adsorbed at fcc and hcp sites on clean Mg (0001) surface, and fcc adsorption site is found to be more preferred. The highest diffusion energy barrier is estimated as 0.6784 eV for the diffusion of hydrogen from clean Mg (0001) surface into its bulk. Surface effects, which affect hydrogen diffusion obviously, results in a slow diffusion velocity of hydrogen from surface to subsurface, while a fast one from subsurface to bulk, indicating the range of surface effects is only restricted within two topmost layers of Mg (0001) surface. Comparatively, Mg atom vacancy on Mg (0001) surface not only enhances the chemisorption interaction between H and Mg surface, but also benefits H atom diffusion in Mg bulk with relatively more diffusion paths compared with that of clean surface. Besides, hydrogen atom is found to occupy mostly the tetrahedral interstice when it diffuses into the Mg bulk. Further analysis of the density of states (DOS) shows that the system for hydrogen atom to be adsorbed at fcc site has a lower DOS value (N (E _F)) at Fermi level and more bonding electrons at the energy range blow the Fermi level of H/Mg (0001) system as compared with that at hcp site. On the other hand, the enhanced chemisorption interaction between hydrogen and defective surface should be attributed to the fact that the electronic structures of Mg (0001) surface are modified by an Mg vacancy, and the bonding electrons of the topmost layer Mg atoms are transferred from low energy range to Fermi level, which is in favor of improving the surface activity of Mg (0001) surface. Supported by the PhD Programs Foundation of Ministry of Education of China (Grant No. 200805321032), the Science and Technology Program Project of Hunan Province (Grant No. 2008GK3083) and the Program for Changjiang Scholars and the Innovative Research Team in university (Grant No. 531105050037)     

The theoretical study of O<Subscript>2</Subscript> adsorption on NiTi (100) and (110) surfaces

The discrete variational Xa method (DV-Xα) within the framework of density-functional theory was applied to study O₂ molecule adsorption on NiTi (100) and (110) surfaces. The bond order and charge distribution between Ti and O atoms for two possible O₂ molecule adsorption ways on NiTi (100) and (110) surfaces were calculated. It is found that the adsorption way for O−O bond perpendicular to NiTi surface is preferred to that for O−O bond parallel to NiTi surface, and O₂ molecule only interacted with one nearest surface titanium atom during the adsorption process. Mulliken population and the partial density of state analysis show that the interaction between Ti and O atoms is mainly donated by O 2p and Ti 4s electrons on NiTi(110) surface, O 2p and Ti 4s, 4p electrons on NiTi(100) surface, respectively. The total density of state analysis shows that NiTi(100) surface is more favorable for O₂ molecule adsorption. HUA Ying-jie: Born in 1966. Funded by the National Natural Science Foundation of China (No. 50081001)     

快速成型中胶黏剂与羟基磷灰石粘结行为研究

在羟基磷灰石多孔支架快速成型制造过程中,为了制造出不易发生断裂的骨支架模型,利用分子动力学模拟方法分别对α?氰基丙烯酸正丁酯和α?氰基丙烯酸正辛酯与羟基磷灰石表面之间的胶粘行为进行研究,重点对其结合能进行了对比,并对羟基磷灰石不同表面的原子密度进行了比较.研究结果表明:在羟基磷灰石(100)、(110)和(111)三个不同剪切面中,聚丙烯酸正丁酯和聚丙烯酸正辛酯均与羟基磷灰石(110)剪切面有较大的结合能;聚丙烯酸正辛酯与羟基磷灰石表面的粘结强度大于聚丙烯酸正丁酯与羟基磷灰石表面的粘结强度.羟基磷灰石多孔陶瓷材料沿(110)方向与粘结剂之间的粘结更稳固,不易产生裂缝及断裂等现象.     

锂原子在Li(100)平坦表面和台阶面吸附扩散的行为

采用足够大的Cluster模拟了理想的Li(100)平坦表面和台阶面。用对势方法计算出了Cluster和Li原子的相互作用势,得到了吸附扩散势能面。给出了最佳吸附位在洞位;最低能量扩散通道为洞位→桥位→洞位。Li原子在台阶面的吸附扩散势表明,下台面形成捕获势、上台面形成反射势。     

三角形网格曲面的展平

提出了一种用于多边形曲面的分步展平方法。将带约束边界条件的全局参数化技术用于生成不规则三角形网格曲面的初始展平图，通过迭代有限元平面热应力求解，可以得到在应变能极小意义下的全局最优展平图。实验结果表明了这种方法的有效性。     

多晶铂电极电催化氧化苯酚的电化学过程

采用循环伏安(CV)、Tafel曲线、交流阻抗(EIS)等方法研究苯酚在多晶铂电极上的电氧化过程.在扫描速度分别为10 mV/s、20 mV/s、50 mV/s、100 mV/s和200 mV/s时,以0.25 mol/L的Na2SO4为支持电解质,考查500 mg/L苯酚在铂电极上氧化的CV曲线变化规律.测试表明发生了不可逆的电氧化反应,氧化峰位置为0.926 V(vs.Ag/AgC l,扫描速度50 mV/s,).苯酚氧化峰电流值与CV扫描速率的关系表明苯酚的氧化反应是由扩散过程和吸附过程共同控制的电化学氧化过程.分别选用0.1和1.0 mol/L的H2SO4溶液为电解液,测试Pt电极析氧反应的Tafel曲线,Tafel斜率为149 mV.采用EIS分析苯酚的电氧化反应,结果表明在高频段存在苯酚吸附的特征容抗弧.     

Insights into the adsorption performance and mechanism of hydrated Ca ion on talc (0 0 1) basal surface from DFT calculation

The utilization of Ca ion as assistant depressant of CMC on talc has been widely reported. Thus, the study on the adsorption mechanism of Ca ion on talc surface is very crucial for understanding the performance of CMC on talc depression. In this paper, mechanism insights into hydrated Ca ion adsorption on talc (0 0 1) basal surface were creatively provided using DFT calculation. [Ca(H₂O)₆]²⁺ and [Ca(OH)(H₂O)₃]⁺ were determined as the effective hydrate components for Ca ion adsorption, and the top O site was the most favorable position for their adsorptions on talc surface. Furthermore, the adsorption mechanisms of [Ca(H₂O)₆]²⁺ and [Ca(OH)(H₂O)₃]⁺ on talc surface were found to be not the Ca—O chemical bond, but the hydrogen bonding formed by the H atom of the H₂O ligand and the surface O atom. H₂O acted like a bridge to connect them to the talc surface. Moreover, the hydrogen bonding was formed due to the hybridization of H 1s orbital with the O 2s, O 2p orbitals. Simultaneously, electrons transferred between the H atom and the surface O atom. This work provides theoretical insights into the Ca ion adsorption on talc surface, which can help deeply understand the talc flotation using CMC as depression.