Thienylmanganese halides for the preparation of regioregular poly(3-hexylthiophene)

For the first time, thienylmanganese halides have been used for the synthesis of regioregular head-to-tail poly(3-hexylthiophene). A variety of conditions were examined, and the polymerization was successfully completed in the presence of Ni(dppe)Cl₂ at ambient temperature affording the title polymer in high yields with excellent regioregularity.     

Preparation and characterization of graphene nanosheets/poly(3-hexylthiophene) thermoelectric composite materials

Graphene nanosheets/poly(3-hexylthiophene) (GNs/P3HT) composites were prepared by oxidative polymerization of 3-hexylthiophene in a GNs dispersed chloroform solution. The phase composition of the composite materials was analyzed by X-ray diffraction and Fourier transform infrared spectra. The thermoelectric properties of the cold pressed composite pellets with different GNs loadings were measured at room temperature. As the GNs loading increased from 0 to 30 wt.%, the electrical conductivity of the composites dramatically increased from ∼10⁻⁶ to ∼1.2 S/cm while the Seebeck coefficient slightly increased from 33.15 to 35.46 μV/K. The highest power factor (∼0.16 μW m⁻¹ K⁻²) was obtained in the 30 wt.% GNs/P3HT composite material.     

Syntheses and characterisation of electrically conductive and fluorescent poly[3-(ω-bromoalkyl)thiophenes]

A novel series of functionalized polythiophenes incorporating 3-(ω-bromoalkyl) pendants were synthesized by chemical oxidative polymerization using FeCl₃ and characterized using FT-IR, UV–Vis absorption spectroscopy, fluorescence emission spectroscopy, conductivity measurements and thermal analyses. These polymers attained a maximum electrical conductivity between 4.7 and 8.4 S cm⁻¹ upon doping with iodine and have a fluorescence quantum yield of up to 11.1% with respect to quinine sulfate. The influence of the terminal ω-bromine substituent as of the length of the alkyl pendant on electrical conductivity, spectral behavior and thermal stability is discussed.     

磷酸盐连接NiFe2O4基金属陶瓷的界面形貌和连接机理

针对铝电解用金属陶瓷惰性阳极材料与金属导杆的电连接困难问题,以Al(H2PO4)3为胶粘剂,CuO为固化剂,NiFe2O4陶瓷粉和Cu-Ag合金粉为填充料,连接NiFe2O4基金属陶瓷.通过分析Al(H2PO4)3与CuO的反应过程,观察磷酸盐连接NiFe2O4基金属陶瓷的界面形貌,探索其高温连接机理.结果表明:Al(H2PO4)3与CuO反应后生成的Cu-P-O化合物是主要连接物相;Cu-P-O化合物随温度的变化逐步发生一系列物相变化,并在960~1 000℃下逐步分解为CuO和P2O5;在不同热处理温度下,磷酸盐与NiFe2O4基金属陶瓷连接界面始终保持紧密结合状态:低温下连接层与金属陶瓷润湿性良好并依靠吸附作用相互连接,高温下连接层与金属陶瓷依靠互扩散作用相互连接.     

La_(0.875)Na_(0.125)MnO_3外延膜的制备及CMR效应

通过射频磁控溅射法在单晶LaAlO3（100）衬底上成功地外延生长了膜厚为90．8nm的La0．875Na0．125MnO3薄膜。用X射线衍射仪、原子力显微镜、超导量子干涉仪、直流四探针法对其进行了表征。结果表明,薄膜为赝立方钙钛矿结构,具有良好的（100）外延取向和光滑表面。居里温度Tc=275K。在居里温度附近,发生铁磁-顺磁转变。此材料呈现出一种典型的自旋玻璃特性,是由于应力造成的。薄膜的电阻率随温度变化的P-T曲线出现双峰。高温电阻峰砟。出现在居里温度附近,来源于铁磁金属体向顺磁绝缘体的转变。而低温电阻峰Tp2出现在T=178K,是由于相分离引起的。在4T强磁场下,相分离现象消失。另外,薄膜的磁电阻曲线也呈现出双峰特征。     

Grain refinement effect of La2(CO3)3 on AZ91 magnesium alloy

The La2(CO3)3 addition makes the grain of AZ91 alloy be refined obviously.The average primary dendrite size of the alloy decreases from 150 to 50 μm.The microstructure of typical dendrite turns into the equal-axed grain with the addition of 2.5 wt.% La2(CO3)3 refiner.The mechanical properties tests indicate that the tensile strength and especially elongation of the alloys are improved with the addition of La2(CO3)3 and their maximum enhancing rates based on the La2(CO3)3-free AZ91 alloy are 26% and 5.2 times at 2.5 wt.% La2(CO3)3 refiner respectively.     

银纳米线的聚醇法制备及其在聚酯和玻璃基板上镀成的透明导电薄膜对比

以聚乙烯基吡咯烷酮(PVP)为稳定剂,聚乙二醇(EG)为还原剂,采用聚醇法[1]制备了银纳米线.根据硝酸银/PVP比例的不同制备了4种类型的银纳米线样品,其中样品D直径最均匀,杂质含量最低.通过改变硝酸银/PVP比例、加入速率和PVP分子量,可对对银纳米线的长度和直径进行控制,得到了小直径(17~100 nm)、大长度(30 nm到100μm以上)的银纳米线.采用XRD、SEM、TEM和紫外-可见光谱对银纳米线的结构进行了表征.采用不同径长比纳米银线混合,以聚对苯二甲酸二乙酯(PET)和玻璃为衬底,分别使用可扩展层压辅助溶液法和旋转涂布法制备了2种透明导电薄膜,其方阻分别为17和26?/sq,透光率分别为88%和80%.     

AOT reverse micelle, a new organized medium for the electrosynthesis of polyaromatic hydrocarbons; application to the electropolymerization of biphenyl

Electrosynthesis of poly(biphenyl) (PBP) films was performed in an AOT [sodium bis(2-ethylhexyl) sulfosuccinate] reverse micelle by cyclic voltammetry and chronopotentiometry on a platinum electrode. An electroactive PBP film was formed either by cyclic voltammetry between −0.6 and 1.65 V/Ag/AgCl or under current control (j = 0.2 mA/cm²). PBP films were characterized electrochemically and spectroscopically (MALDI-TOF mass spectrometry), NMR, Raman, FT-IR, X-ray photoelectron and UV–vis spectroscopy). The structure of the PBP films involved sequences of ramified trimer possessing quinoid forms. This type of sequences can give strongly condensed oligomers with PBP molar mass up to 2669.6 g/mol according to the electrosynthesis charge.     

开发软件OEM下界面的编制

以西门子840D数控系统为开发平台，利用西门子提供的专用开发软件OEM为M84125轧辊磨床开发一套符合设计要求的控制界面。西门子840D数控系统提供了OEM软件，其中包括VB和VC＋＋的接口，用户可以通过VB设计特殊界面，根据要求编制用于复杂计算的程序，利用VC＋＋创建和西门子数控系统相联系的语言动态链接库，利用西门子数控系统提供的开发环境和VB、VC＋＋接口实现用户的特殊界面及加工方法嵌入西门子系统。本文重点介绍OEM环境下界面的编制。     

稀土空位锰氧化物(La(1-x-y)Yy)2/3Ca1/3MnO3的结构和输运性质

用固相反应法制备了La(1-x)2/3Cai/3MnO3(V-LCMO)和(La(0.7-x)Y0.3)2/3Cai/3MnO3)(V-LYCMO)(x=0,0.02,0.04,0.08,0.10)系列La空位锰氧化物样品.X射线衍射(XRD)分析表明:所有的样品均为单相,具有正交对称性(Pnma).La(1-x)2/3Cai/3MnO3系统和(La(0.7-x)Y0.3)2/3Cai/3MnO3系统的晶格参数以及Mn-O键长和Mn-O-Mn键角随La空位浓度不同而改变,说明在室温系统中存在Jahn-Teller效应.对于V-LYCMO系统,其晶格参数、Mn-O键长和Mn-O-Mn键角都比V-LCMO相应的值更小,这可能与离子半径小的Y3 部分替代La3 导致更大的晶格畸变有关.V-LCMO系统随着空位浓度的增大,绝缘体-金属的转变温度TMI几乎不变.在x=0.04时MR值在温度TMI处达到最大值,约为220%(8T).而对V-LYCMO系统,其转变温度TMI约为50 K,在温度40～50 K左右最大的磁电阻值超过106%.认为很大的磁电阻效应与用离子半径小的Y部分替代离子半径大的La有关,它会破坏双交换作用,从而导致Jahn-Teller效应.     

3DEC modeling on effect of joints and interlayer on wave propagation

1 Introduction Natural rock mass is not homogeneous, and it is full of various weak planes with different structures and different geological mechanisms, such as fractures, joints, and cracks. These structural weak planes seriously hinder and affect the …     

Synthesis and characterization of a conducting copolymer

By a simple and relatively easy method, we have synthesized a copolymer including alternatively p-phenylene vinylene and ether groups. The physicochemical characterization of this polymer has shown a high thermal stability, an amorphous structure and a small molecular weight (M_n ≈ 1100). The preliminary electrooptical study of this material shows an intense luminescence and a rectifying character of the polymer—metal contact.     

铸件热应力模拟中铸件/型(芯)相互作用的研究进展

铸造过程热应力分析是当前铸件数值模拟领域的研究重点和热点之一.其中铸件/型(芯)之间的相互作用的处理直接影响铸件铸造过程热应力分析的准确性.介绍了国内外处理铸件/型(芯)热力相互作用的研究进展,接触单元法是三维复杂铸件应力模拟发展的趋势.文章还介绍了砂型材料高温力学性能的研究情况.     

固体氧化物燃料电池铬酸镧连接材料研究现状

掺杂二价减土金属的铬酸镧是目前研究最深入,应用效果最好的固体氧化物燃料电池（SOFC）的连接材料,它几乎占整个SOFC制造成本的一半,本文就其研究现状进行了综述。     

氧化铝增韧陶瓷的高效ELID精密磨削实验研究

氧化物增韧陶瓷是一种高技术陶瓷材料,具有高强度、高韧性以及良好的耐磨、耐腐蚀性能。在一般的加工过程中,采用普通树脂砂轮对硬度较高的氧化铝增韧陶瓷材料进行磨削时,磨料的消耗比较快,磨削比较低,仅为8,10左右。通过ELID磨削对氧化铝陶瓷进行高效磨削实验,从砂轮速度、进给速度、砂轮粒度和砂轮电解活化钝化趋势等因素中,找到合适的加工工艺参数,使效率和精度达到最优。实验表明,砂轮速度和进给速度对磨削比影响较大;砂轮粒度和砂轮电解活化钝化趋势对表面质量影响较多。使用优化后的ELID磨削工艺使氧化铝陶瓷材料的加工效率提高了50％。磨削比增大到60～100。     

Differences of grain-refining effect of Sc and Ti additions in aluminum by empirical electron theory analysis

The differences of grain-refining effect between Sc and Ti additions in aluminum,which cannot be substantially explained by traditional theories,were carefully studied.The empirical electron theory(EET) of solids and molecules was employed to calculate the valence electron structures(VES) of Al3Ti and Al3Sc.The conclusions can be drawn that,in the two alloys Al-Ti and Al-Sc,the different valence electron structures of Al3Ti and Al3Sc and the consequent differences of growth habit of the two particles,and th...     

Dielectric barrier discharge (DBD) processing of PMMA surface: Optimization of operational parameters

This paper reported the effects that the key dielectric barrier discharge (DBD) operating parameters, discharge power, processing speed, processing duration and electrode configurations, have on producing wettability changes and on uniformity in the PMMA surface region. The results obtained indicate that DBD plasma processing is an effective method for the controlled surface modification of PMMA. Relatively short exposures to the atmospheric pressure discharge produces significant wettability changes at the PMMA surface, as indicted by pronounced reductions in the water contact angle measured. It was observed that the wettability of the resultant surface shows no significant differences in respect to sites in orientation parallel (L-direction) or perpendicular (T-direction) to the electrode long axis. However, the resultant surface shown higher standard deviation (S.D.) of contact angle in T-direction than that in L-direction. Analysis of the role of each of the operating parameters concerned shows that they have a selective effectiveness with respect to resultant surface modification in terms of uniformity of modification and wettability. The number of treatment cycles and the discharge power used were found to have the most significant effects on the homogeneity of the resultant PMMA surface changes in L- and T-orientation, respectively. The number of treatment cycles was found to be the dominant factor (at significance level of 0.05) in respect of water contact angle changes at the processed PMMA surface in both orientations. The driven metal electrodes (stainless steel or aluminium) were apparently superior to the driven dielectric electrode (ceramic or quartz) configurations. The grounded electrode in each case was a silicone rubber-covered aluminium plate. The nature and scale of the surface changes that originate from the various processing conditions employed have been considered so as to determine the optimum treatment conditions in respect of processing outcomes, properties and any orientation dependence. It was revealed that higher processing speeds and longer processing durations are key for uniformity along the electrode axial orientation within the test range employed, while lower processing speeds and short exposure durations are key considerations, in the corresponding perpendicular orientation. In general, longer processing durations (low processing speeds and a high number of treatment cycles) and higher plasma powers induced greater changes in the surface wettability of the PMMA, as demonstrated by the observed water contact angles. This behaviour is taken to indicate that different combinations of DBD operating parameters and electrodes produce discharge conditions that can result in different plasma chemical processes in respect of uniformity, treatment efficiency and orientation dependence. The comparison of the processing outcomes between PMMA and PET revealed that the operating parameters have the similar selective effectiveness on both polymers, indicating the obtained results may be used as a general guidance in controllable surface processing by DBD technique.     

铁触媒表面的氧化铁包覆层对金刚石成核的影响

为了研究氧化后的触媒对金刚石成核的影响，将α-Fe粉在400℃的空气氛中分别处理1，1．6，2．4和4小时，制备了不同包覆厚度的氧化铁包覆铁粉。采用氧化铁包覆的铁触媒粉末和石墨体系进行了金刚石合成研究。研究发现在5．7GPa和1600℃的条件下，铁触媒表面的氧化铁包覆层与石墨碳发生了氧化还原反应生成Fe3O4和FeO，同时包覆层内部的铁熔融渗出，并与石墨碳源接触促使了金刚石的成核生长。与纯铁触媒相比，氧化铁包覆层对金刚石成核具有明显的抑制作用，而且随着包覆层厚度的增加，抑制作用越明显。文中还借助穆斯堡尔谱、X-ray衍射和扫描电镜测试手段对上述实验机理进行了深入的探讨。     

B(CH_3O)_3等离子辅助渗硼的研究

研究了新型渗硼剂Ｂ（ＣＨ３Ｏ）３的分解离化行为及渗硼工艺。结果表明：在室温条件下Ｂ（ＣＨ３Ｏ）３主要分解离化为Ｂ（ＣＨ３Ｏ）Ｈ＋、Ｂ（ＣＨ３Ｏ）ＯＨ＋和Ｂ（ＣＨ３Ｏ）２＋;在设计的工艺条件下可以得到均匀致密的渗硼层