碳纳米管／纳米TiO2复合膜电极与纳米TiO2电极电化学性能比较

本文采用TEM、循环伏安、阻抗-电位等方法,研究比较了碳纳米管／纳米TiO2复合膜（CNT／nano—TiO2）修饰电极与纯纳米TiO2（nano—TiO2）膜电极电化学性能的差异。大量细小的碳纳米管的存在,可起到阻碍TiO2纳米粒子的团聚作用,从而提高了CNT／nano-TiO2修饰电极的电化学性能。     

碳纳米管/纳米TiO2-聚苯胺复合膜电极的电化学制备

在含有0.2 mol.L-1苯胺的0.5mol.L-1H2SO4溶液中,采用循环伏安法(CV),以扫描速度50mv.s-1,扫描电位为-0.1～0.9V,在碳纳米管/纳米TiO2(CNT/nanoTiO2)膜电极上实现了苯胺的电化学聚合,并通过扫描电镜对膜层的微观形貌进行观察,发现这种在纳米基体上聚合得到的聚苯胺膜呈疏松、多孔的纳米纤维网状结构,不同于在金属基体上聚合得到的颗粒状聚苯胺膜.     

Physical properties of the junction of scandium and carbon nanotubes

Using first-principles calculations, the contact between the scandium (Sc) and semiconducting carbon nanotube (CNT) is investigated. This is one of the best quality of n-type contacts. Two junction models with (8,0) CNT on low-index Sc surfaces are constructed to elucidate the structural and electronic properties of Sc/CNT junctions. Analyses based on density of states and charge difference reveal that strong chemical bonds are formed between Sc and C atoms due to hybrid states of Sc 3d state and C 2π state. With respect to Ti(0001)/CNT junction, we find the dipole layer formed at the interface of Sc(0001)/CNT is comparable with that of Ti(0001)/CNT but gives a negative barrier at the interface. This indicates that the excellent contact properties of Sc metal electrode are caused by its low work function and excellent binding with CNT.     

含CNT夹层的PbO_2电极电催化氧化水中苯胺的研究

结合电泳法和电沉积法制备了含碳纳米管(CNT)夹层的PbO_2电极(CNT-PbO_2),扫描电子显微镜图像表明,在CNT夹层表面电沉积10minβ-PbO_2活性层可获得β-PbO_2晶粒较多、晶粒尺寸较小、比表面积较大的CNT-PbO_2电极。利用CNT-PbO_2电极电催化氧化降解水中苯胺,研究电流密度、苯胺初始浓度、温度、支持电解质浓度对苯胺降解率的影响。实验结果表明:随着电流密度的增加,苯胺的降解率升高;苯胺初始浓度越高,苯胺的降解率越低;在实验范围内,温度和支持电解质浓度对电催化氧化降解苯胺过程影响较小。     

铝硅掺杂碳纳米管吸附CO气体的密度泛函理论研究

采用第一原理密度泛函方法对CO分子在纯、掺杂（Al、Si）碳纳米管上的吸附行为进行了研究。研究表明,掺杂碳纳米管对于CO气体分子的吸附能明显大于纯的碳纳米管。吸附CO分子后,较之纯的碳纳米管,掺杂体系的电子态密度及Mulliken电荷均有明显的变化,特别是铝掺杂碳纳米管的变化更明显。铝原子掺杂碳纳米管有望成为探测CO气体分子的传感材料。     

Ce~(3+)在Pt/nanoTiO_2-CNT电极上的电催化氧化

以电合成前驱体Ti(OEt)4直接水解法和电沉积法制备Ti基纳米TiO2-碳纳米管复合膜载P(tPt/nanoTiO2-CNT)复合电极。透射电镜(TEM)和X射线衍射(XRD)测试表明,锐钛矿型纳米TiO2粒子和Pt纳米粒子(粒径约8nm)均匀地分散在碳纳米管表面。通过循环伏安法研究Pt/nanoTiO2-CNT电极对Ce3+的电催化性能,Ce3+氧化峰电位约为1.27V(vs.SCE),比Pt/nanoTiO2电极负移30mV,峰电流约高45mA·cm-2。     

NOTETAKING SKILLS INSTRUCTION FOR DEVELOPMENT OF MIDDLE SCHOOL STUDENTS’ NOTETAKING PERFORMANCE

The objective of this study was to investigate the effects of explicit instruction in notetaking skills on the notetaking performance of seventh‐grade students at different reading ability levels. The students in the notetaking instruction condition (NTI) received classroom‐based notetaking skills instruction (approximately 40 minutes) every week for 10 weeks. The comparison condition students (CNT) were asked to use conventional notetaking (CNT) that was embedded within the daily social studies lessons. The participants’ reading comprehension abilities were identified through the Sentence Verification Technique, which consisted of a 16‐item expository text. A notetaking performance test (NTPT) was used to assess the effect of notetaking skills instruction on two dimensions of the participants’ notes (verbatim copying and terse value). The results demonstrated that the terse value of students’ notes in the NTI condition was significantly better than that of the students in the CNT condition. The students in the NTI condition reduced their percentage of verbatim copying and used fewer words to cover more main concepts in the NTPT that followed the instructional intervention. Surprisingly, the students at low reading ability showed the greatest gains in notetaking performance from verbatim copying to terse notetaking.     

Synthesis of polyketone by copolymerization of styrene and CO using carbon nanotube-complex Pd2+ catalyst

The dipping method was devised to deposit Pd onto carbon nanotube as supported catalyst(Pd/CNT) for the copolymerization of carbon monoxide(CO) and styrene(ST) towards the formation of polyketone(PK).The Pd/CNT was characterized by X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD) and high-resolution transmission electron microscopy(HRTEM).The construction and crystallization property of PK were evaluated by Fourier transform infrared spectroscopy(FTIR),13C-nuclear magnetic resonance(NMR) and XRD,respectively.The catalyst showed excellent activity and reusability in promoting the fabrication of PK.It can be recycled 14 times with the highest total catalytic activity of 4 239.64 gPK/(gPd·h) at Pd content of 8.63wt%.The results indicate that the prepared catalyst is effective to catalyze the copolymerization of CO and styrene.     

Effect of substrates and underlayer on CNT synthesis by plasma enhanced CVD

Due to their unique thermal, electronic and mechanical properties, carbon nanotubes （CNTs） have aroused various attentions of many researchers. Among all the techniques to fabricate CNTs, plasma enhanced chemical vapor deposition （PECVD） has been extensively developed as one growth technique to produce verticallyaligned car bon nanotubes （VACNTs）. Though CNTs show a trend to be integrated into nanoelectromechanical system （NEMS）, CNT growth still remains a mysterious technology. This paper attempts to reveal the effects of substrates and un derlayers to CNT synthesis. We tried five different substrates by substituting intrinsic Si with high resistivity ones and byincreasing the thickness of SiO2 insulativity layer. And also, we demonstrated an innovative way of adjusting CNT den sity by changing the thickness of Cu underlayer.     

碳纳米管阴极微波管的电子束聚束系统设计

为了控制碳纳米管阴极发射电子束的形状,设计了4种电子通道来控制电子束轨迹.在设计结构中,其基本结构是一倒置的内壁涂有绝缘材料的漏斗状通道.当初始电子碰撞绝缘壁时,会产生二次电子,而二次电子能改善电子在通道出口处的电子能量分布的均匀性.通过分析和比较电子在通道出口处的状态,得到了一种理想的通道结构.在该结构中,电子在通道出口处的分布更加均匀,电子束的束径较小.而且通过在慢波线外部加磁场的方法来控制电子束在慢波线中的扩散,所加的磁场越大,电子在慢波线中的通过率则越大.通过分析4种不同的结构,在所得到的一种理想的通道结构中,需要较小的磁场就能使得电子在慢波线中的通过率较高.     

关于Diophantine方程(4/n)=(1/x)+(1/y)+(1/z)

利用分数的单位分数分拆技巧,讨论了Diophantine方程4/n=1/x+1/y+1/z,证明除了mod 840的11个剩余类的例外情形,Erdos猜想成立。     

B/S模式和C/S模式优势比较

主要介绍了C／S模式的两个发展阶段，即两层结构和三层结构，二层结构的不足以及三层结构相对于二层结构的优势；B／S模式的三层客户服务体系；介绍了C／S模式和B／S模式的各自的优势，并分析了两种模式的结合策略。     

Sexual assemblages: mobile phones/young people/school

This paper asks, what more can we think in relation to debates around young people's use of mobile phones at school? Rather than attempting to answer the question of whether mobile phones are ‘good’ or ‘bad’ for young people, this paper recasts the debate's ontological underpinnings. To do this feminist appropriations of the Deleuzian concept of assemblage and a relational materialist notion of ‘more-than-human’ are drawn on. By recognising sexuality-as-assemblage, it is possible to see more-than-human elements (such as mobile phones) as implicated in the becoming of sexuality at school. This conceptualisation implies new texture and dimensionality to the wider project of (re)producing sexual meanings and identities at school. It also necessitates acknowledging an ontologically different understanding of the human-non-human divide, that decentres young people and/or phones as to ‘to blame’ for ‘negative’ practices like sexting. Instead, agency manifests via the intra-activity that occurs when mobile phones and young people are in-relation.     

Learning Together: The Student/Parent/Teacher Triad

This report contains an analysis of both quantitative and qualitative data on participant perceptions of the co‐production of learning. It constitutes a refinement of the working model of the triadic relationship between parents, students, and teachers which was the basis of previous reports (Coleman, Collinge, & Seifert, 1992; Coleman, Collinge, & Tabin, 1992; Coleman & Tabin, 1992; Coleman & Collinge, 1991). Given our earlier findings the focus in this paper is upon the theme of collaboration, which is emerging as one critical element in the relationships within the student/teacher/parent triad.

The analysis shows that there are sharp differences in perceptions of collaboration between different triad members. Collaboration between parents and students is perceived to be both strong and balanced in initiation. Teachers show little awareness of its strength. Collaboration between teachers and parents is perceived by both to be one‐sided; each party sees the other as unresponsive. It is invisible to students. Collaboration between students and teachers varies between classrooms, and seems to be based upon the teachers’ perception of student acceptance of responsibility; parents are very keenly aware of this collaboration where it exists. Classroom level differences are also strong; teacher attitudes and practices clearly determine the extent of collaboration.

In British Columbia parent and student attitudes towards classrooms and teachers are affected, sometimes strongly, by teacher practices of parent involvement. These attitudes contribute to parent and student rating of particular schools.     

Research on the Mistakes Made by College English Teachers in Pronunciation of /n/&/l/

As an old saying goes that“once you open mouth, you are decided”. Thus, there is no doubt about the fact that English pronunciation is of great importance, especially for English teachers whose pronunciation exerts far-reaching and direct influences on that of students. Some of College English teachers, however, have poor pronunciation; most of them cannot distinguish/n/ from /l/. Therefore, it is of huge practical value to commit to the research on the mistakes made by College English teachers in pronunciation of /n/ &/l/ and analyze the underlying causes in the hope of helping teachers to improve their poor pronunciation.     

H3PW6Mo6O40/SiO2催化合成苯甲醛1,2-丙二醇缩醛

以二氧化硅负载磷钼钨酸H3PW6Mo6O40/SiO2为催化剂,苯甲醛和1,2-丙二醇为原料合成苯甲醛1,2-丙二醇缩醛.探讨H3PW6Mo6O40/SiO2对缩醛反应的催化活性,较系统地研究了醛醇物质的量比、催化剂用量、带水剂用量、反应时间等因素对产品收率的影响.实验表明:H3PW6Mo6O40/SiO2是合成苯甲醛1,2-丙二醇缩醛的良好催化剂,在n(苯甲醛)∶n(1,2丙二醇)=1∶1.5,催化剂用量为占总反应物质量的1.0%,带水剂环己烷用量10 mL,反应时间45 min的最佳条件下,苯甲醛1,2-丙二醇缩醛的收率可达83.3%.     

NetBEUI、IPX／SPX、TCP／IP之比较

目前较流行的通信协议有NetBUEI、IPX／SPX、TCP／IP等，NetBEUI适合小型局域网，IPX／SPX则为Novell网的通信协议，TCP／IP为Internet协议，IPX／SPX、TCP／IP为可路由协议，NetBEUI、IPX／SPX不需设置，TCP／IP需设置其“IP地址”、“子网掩码”、“默认网关”、“主机名”等。     

UHV／CVD生长SiGe／Si材料分析及应用研究

以Si2H6和GeH4为生长气源,采用UHV／CVD系统在Si（100）衬底上生长了Sil—xGex合金和Sil—xGex／Si多量子阱结构。采用X射线双晶衍射仪、扫描电子显微镜和原子力显微镜等仪器设备对样品的组份、界面和表面形貌等晶体质量进行了研究。SiGe合金中Si和Ge摩尔分数的比值随着Si2H6和GeH4流量比的增加按比例线性增加,比例因子为2．57。生长的Si0．88Ge0．12合金样品的界面清晰,表面平整,平均粗糙度仅为0．4nm,位错密度低于104／cm2。六周期Si0．88Ge0．12／Si多量子阱的X射线双晶衍射摇摆曲线中存在多级卫星峰和Pendellosung条纹。这些结果表明SiGe合金和SiGe／Si多量子阱均具有很好的晶体质量。     

mpg-C3N4/BiVO4异质结光催化剂的制备及其降解复方磺胺甲恶唑的效果研究

采用水热合成法制备了典型的手里剑型钒酸铋晶体（BiVO₄）,利用硬模板法制备了介孔氮化碳材料（mpg-C₃N₄）,运用超声分散的方法将二者复合,制得mpg-C₃N₄/BiVO₄异质结光催化剂。文章考察了其在可见光条件下降解复方磺胺甲恶唑的效果,并探讨了影响降解效果的因素。