(La0.67Ca0.33MnO3)x/(ZrO2)1-x复合体系的磁性和传输特性

将用溶胶-凝胶法得到的La0.67Ca0.33MnO3(LCMO)微粉与ZrO2的颗粒进行复合,制备了(LCMO)x/(ZrO2)1-x渗流复合体系.当LCMO的体积分数为40%时,复合体系达到渗流阈值,此时材料在低温下的磁电阻得到显著增强.77 K时在10 mT的磁场下,(LCMO)0.4/(ZrO2)0.6的磁电阻比为7.8%,相对于LCMO增加了712%.低场磁电阻(LFMR)的增强是由于载流子在二者界面处发生的自旋相关隧穿效应.由于界面反应,不可避免地产生了Zr离子对Mn离子的B位替代,从而引起材料磁性M和居里温度Tc的下降.在x＜60%时,Tc保持在220 K附近基本不变,说明该B位替代是有限的.     

活性正离子聚合制备聚(异丁烯-b-α-甲基苯乙烯)嵌段共聚物

以2-氯-2,4,4-三甲基戊烷(TMPCl)/TiCl4/质子捕捉剂(DtBP)为引发剂体系,引发异丁烯聚合,随后加入1,1-二(4-甲基苯基)乙烯作为封端剂稳定末端碳正离子,再引入四异丙醇钛(Ti(OiPr)4),降低Lewis酸性,继续引发α-甲基苯乙烯聚合,实现活性正离子聚合制备聚(异丁烯-b-α-甲基苯乙烯)嵌段共聚物.考察了α-甲基苯乙烯聚合时间对单体转化率、产物的dn/dc值、分子量及其分布的影响以及四异丙醇钛对聚合速率的影响.并通过体积排斥色谱法/紫外检测器/示差折光指数/多角激光光散射、1H-NMR以及DSC以对产物进行表征.实验结果表明,嵌段共聚物分子量分布窄(MWD≤1.2),单体转化率与分子量呈线性关系,聚合速率对单体浓度呈一级动力学关系,具有活性聚合的特征.Ti(OiPr)4能有效稳定活性中心,降低聚合速率.聚(异丁烯-b-α-甲基苯乙烯)嵌段共聚物的DSC测试发现明显的两个Tg,表明存在微相分离结构.     

钛基导电氧化物电极上氧的阳极析出动力学与机理研究

本文通过在碱溶液中Ti/RuO_2+TiO_2(A)和Ti/SnO_2+CuCo_2O_4(B)电极上氧阳极析出动力学的对比研究, 表明这两类电极上氧的极化曲线均有两Tafel区。低极化区的Tafel斜率为0.039V(简称b_1区); 高极化区为0.120V(简称b_2区)。在A电极上b_1区i～a_W·a_(OH~-); b_2区i～a_W(浓碱溶液)或i～a_(OH)~(0.1～0.5)(稀碱溶液),在B电极上b_1区i～a_(OH~-); b_2区i～a_(OH~-)~(0.39)(浓碱溶液);或i～a_(OH~-)(稀碱溶液), 实验结果表明, 虽然这两类电极上氧阳极析出过程都由第二电子转移步骤控制, 但其机理不同, 前者是由水分子参加, 控制步骤为RuO_2·OH_(ads)+H_2O ~(rds)→ RuO(OH)~+_3+e后者则为 (SOH)~(n+)_(ads) ~(rds)→ (SOH)~((n+1)+)_(ads)+e它们与PbO_2、Pt和低碳钢上机理有些不同~[1,2]。     

A1掺杂量对正极材料LiNi_(1/3)Co_(2/3-x)A1_xO_2结构和电化学性能的影响

以共沉淀法合成的前驱体Ni_(1/3)Co_(2/3-x)Al_x(OH)_2与低共熔锂盐0.38LiOH·H_2O-0.62LiNO_3制备了锂离子电池正极材料LiNi_(1/3)Co_(2/3-x)Al_xO_2(x=1/12,1/3,1/2,7/12).采用X射线衍射(XRD)、扫描电镜(SEM)和电化学性能测试对其结构、形貌和电化学性质进行表征.结果表明,LiNi_(1/3)Co_(2/3-x)Al_xO_2在1/12≤x≤1/3范围内可以保持单一的六方层状a-NaFeO_2结构,当A1掺杂量(x)高于1/3时,会出现杂相.其中,LiNi_(1/3)Co_(1/3)Al_(1/3)O_2结晶程度最高,阳离子混排效应最小,并且颗粒小而均匀,振实密度可以达到2.88 g·cm~(-3),首次放电容量为151.5 mAh·g~(-1),循环50次后放电容量保持在91.4%,在1C和2C倍率下放电容量仍可达到133.7和120.9 mAh·g~(-1)     

ZrO_2及SO_4~（2－）／ZrO_2超强酸催化剂的XRD分析

用ＸＲＤ技术从定性和定量上对ＺｒＯ＿２，特别是超强酸催化剂的物相和四方相ＺｒＯ＿２的含量进行了详细的考察。结果表明，的引入使的晶化温度比ＺｒＯ＿２大约提高了１００Ｋ，并且使亚稳态四方相ＺｒＯ＿２得以稳定。亚稳态四方相ＺｒＯ＿２的含量主要受处理液浓度和焙烧温度的影响。处理液浓度越大，四方相含量越高；焙烧温度越高；四方相含量越低。强酸性的Ｈ＿２ＳＯ＿４溶液比弱酸性的（ＮＨ＿４）＿２ＳＯ＿４溶液对四方相的生成更有利。在无定形ＺｒＯ＿２、四方相ＺｒＯ＿２和单斜相ＺｒＯ＿２上的稳定性依次减小。     

O2结构Liy[Mn1—xMx]O2（M＝Cr，Mg）的合成及结构研究

由高温焙烧法制备层状前驱体Na_(2/3)[Mn_(1-x)M_x]O_2（M＝Cr, Mg），再 经离子交换反应得到层状O2结构产物Li_y-[Mn_(1-x)M_x]。XRD表明Li_y[Mn_(1-x) M_x]O_2属六方晶系，P3ml空间群。Cr的添加量对前驱体的晶体结构有很大影响： 随着x值的增大，前驱体逐渐由层状P2结构Na_(2/3)[Mn_(1-x)Cr_x]O_2向正交结构 Na_4Mn_90_(18)转变。由SEM可以看到样品Li_y[Mn_(1-x)Cr_x]-O_2(x≤0.05)具有 六方层状结构。XPS分析结果表明样品Li_y[Mn_(0.95)Cr_(0.05)]O_2表面上的Mn和 Cr分别以Mn~(4+)存在，并且表面中Cr相对含量高于体相，而样品Li_y[Mn_(0.90) Mg_(0.10)]O_2的表面Mn和Mg分别以Mn~(4+)和Mg~(2+)存在，Mg/Mn比在表面与体相 基要一致。     

Microstructural Exploration of the High Capacitance in RuO_2-ZrO_2 Coating

A high capacitance RuO₂-ZrO₂ coating was prepared by thermal decomposition method.Extended X-ray absorption fine structure(EXAFS),X-ray diffraction(XRD),high-resolution transmission electron microscope(HRTEM)and ab initio calculations were applied to understand the role of the microstructure in the acquisition of high specific capacitance of RuO₂-based oxides.The results show that the RuO₂-ZrO₂ oxide prepared at critical crystallization temperature can be considered to be quasi-amorphous or microcrystalline(A short-range ordered crystal structure can be seen from the TEM image,but no diffraction peaks can be seen from the XRD diffraction patterns).And this RuO₂-ZrO₂ was identified as a solid solution with high solid solubility.It referred to herein as a quasi-amorphous solid solution.Such a special microstructure was conducive for"synergistic catalysis"owing to the cationic interaction and thus could gain high"active site density"and high"active surface",thus developing high specific capacitance.     

碱液回流老化ZrO(OH)_2制备纳米晶ZrO_2的影响因素

通过考察回流老化所用的碱液（NH_4OH, NaOH和KOH）介质和容器材质（玻璃 和Teflon）对ZrO(OH)_2凝胶及其焙烧产物ZrO_2的织构／结构和热稳定性的影响， 研究了杂质元素掺杂和凝胶溶解－再沉淀等因素在形成高表面积纳米晶ZrO(OH) _2/ZrO_2过程中的作用。在Teflon容器中，以NH_4OH为介质（pH = 11.5）的回流 老化对ZrO(OH)_2/ZrO_2的性质无明显影响。而使用玻璃容器则可显著提高ZrO(OH) _2/ZrO_2的表面积、孔容和抗烧结性质，并在800℃获得小晶粒（5～7 nm）四方晶 相ZrO_2纳米晶材料；在DTA曲线上ZrO(OH)_2转变成ZrO_2晶体的温度由回流老化前 的463℃提高到810～840℃。在以KOH和NaOH为介质(pH = 13)的实验中，使用玻璃 容器得到与经NH_4OH为介质时相类似的结果；但在Teflon容器中只形成低表面积和 较大尺寸（约20 nm）以单斜相为主的混合晶相ZrO(OH)_2，其在800℃焙烧后形成 大晶粒（35 nm）单斜相ZrO_2。样晶的元素分析结果清楚地揭示出使用玻璃容器时 有SiO_2从器壁溶解掺杂进入ZrO(OH)_2凝胶。样品的表面积和孔容与杂质Si~(4+) 含量之间有顺变关系，表明Si~(4+)掺杂是形成高表面积和大孔容ZrO(OH) _2/ZrO_2、提高ZrO_2晶化温度以及稳定小晶粒四方晶相ZrO_2的最主要因素。在不 发生Si~(4+)掺杂前提下，K~+和Na~+的存在可促进ZrO(OH)_2形成结晶，但对高温 下ZrO_2织构的稳定性影响不大。此外，ZrO(OH)_2凝胶的溶解－再沉淀和骨架网络 有序化也是回流老化影响ZrO(OH)_2/ZrO_2织构的重要因素。     

STUDIES ON SYNTHESIS, STRUCTURE AND REACTIVITY OF ACTIVATED Os_6 RAFT-LIKE CLUSTERS

In this paper we report the synthesis and activation of OS-6 raft-llke planar clusters. The activated OS-66 raft-like clusters [OS-66(CO)_(20)(MeCN)] and [OS-66(CO)_(19) (MeCN)_2] have been prepared by involving PdCl_2 as catalyst. Trimethylamine oxide (Me_3NO) has been used as an activation reagent to oxidize several carbonyl ligands coordinated in the activated clusters and to get a series of activated OS-66 raft-like clusters [OS-66(CO)_(21-x)(MeCN)_x] (n = 1--5) and corresponding substituted clusters [OS-66(CO)_(21-x)(P(OMe)_3)_x] (n=1--5). The structures of these OS-66 raft-like clusters have been characterized by the infrared spectra (IR), nuclear magnetic resonance spectra (NMR) and mass spectra (MS), and the characters of the raft-like planar structure and reactivity above have also been discussed in this paper.     

固体超强酸（SO4^2-／ZrO2）的异丁烷／1-丁烯烷基化反应性能和失活研究

研究了固体超强酸(SO4^2-／ZrO2)催化剂的酸性及异丁烷-1-丁烯烷基化反应性能，结果表明，固体超强酸的酸性与焙烧温度有关，适当提高焙烧温度有利于样品酸强度的提高，但焙烧温度过高会导致脱硫，使样品酸强度和酸量降低，固体超强酸的异丁烷／1-丁烯烷基化催化反应活性与其酸性相对应，酸性强，反应活性高，但催化剂的活性衰减很快，这是催化剂表面的快速积炭所致。     

Thermal Properties of K（Y1-xYbx）（WO4）2（x=0.098,0.196,0.294） Crystal

Thermal properties of pure KY(WO4)2 and K(Y1-xYbx)(WO4)2(x=0.098,0.196,0.294) crystals were investigated.The specific heat and thermal diffusivity of crystals were calculated at a range of 50～300 ℃.The calculated result shows that the specific heat and thermal diffusivity of K(Y1-xYbx)(WO4)2(x=0.098,0.196,0.294) crystals were slightly affected by the Yb3+ concentration.The thermal expansion coefficient of K(Y0.804Yb0.196)(WO4)2 crystals along x,y and z axes were determined to be 13.51,4.474 and 16.60×10-6 K-1,respectively.These results suggest the K(Y1-xYbx)(WO4)2(x=0.098,0.196,0.294) crystal as a laser crystal of low-middle power.     

Ti/Ru0.1Ti0.1Sn0.8O2电极电容性能研究

低温热分解法制备Ti/Ru0.1Ti0.1Sn0.8O2.XRD表征该样品结构特性,循环伏安和恒流充放电测定电极性能.结果表明,Ti/Ru0.1Ti0.1Sn0.8O2物相属细小的金红石相,在20 mV/s扫速下该电极比电容达933F/g.1000次充放电循环后,比电容衰减23.6﹪,显示良好的循环稳定性和可逆性.     

聚[2-(2-氯乙氧基)乙氧基)_x(三氟乙氧基)_(2-x)]磷腈合成和气体分离性能研究

六氯环三聚磷腈经二次重结晶一次减压升华纯化后,通过真空热开环聚合和亲核取代反应,用不同摩尔比的2-(2-氯乙氧基)乙醇钠和三氟乙醇纳(1∶3;1∶5;1∶6.5)作为亲核取代试剂混取代聚二氯磷腈,再经多次非溶剂沉淀纯化得到目标聚合物聚[(2-(2-氯乙氧基)乙氧基)x(三氟乙氧基)2-x]磷腈.利用31P-NMR监测,以确保得到纯化的聚合物.采用1H-NMR、FT-IR、GPC、DSC、XRD等测试手段对所得到的聚合物进行了结构表征和性能测试,并利用自制的压力法透气性能测定仪测定了这些聚合物的气体渗透系数.结果表明,三氟乙氧基和2-(2-氯乙氧基)乙氧基两种基团已接枝在聚磷腈侧链上,分别得到x值为0.19,0.18和0.08的3种聚[(2-(2-氯乙氧基)乙氧基)x(三氟乙氧基)2-x]磷腈,其玻璃化温度分别为-6.37℃,-12.85℃和-25.68℃,重均分子量为5.4×105,6.8×105和1.5×105,在同样的反应条件下,三氟乙氧基较2-(2-氯乙氧基)乙氧基有更强的竞争取代率.这种混取代聚磷腈较单一取代基的聚三氟乙氧基磷腈结晶度小,在本实验中两种取代基比例适中的聚[(2-(2-氯乙氧基)乙氧基)0.18(三氟乙氧基)1.82]磷腈的结晶度降至10.1%,这种聚合物显示出较高的气体渗透系数,CO2和He的气体渗透系数达到88.9和60.6 barrer,CO2/CH4和He/CH4的选择系数达到24.1和16.4,在天然气行业显露出良好的应用潜力.此外这类聚合物表现出特殊的H2/N2选择性,选择系数在0.2左右,N2的渗透系数为8.5 barrer,因而在合成氨行业显示出特殊的应用潜力.     

New barium copper chalcogenides synthesized using two different chalcogen atoms: Ba2Cu(6-x)STe4 and Ba2Cu(6-x)Se(y)Te(5-y)

Ba(2)Cu(6-x)STe(4) and Ba(2)Cu(6-x)Se(y)Te(5-y) were prepared from the elements in stoichiometric ratios at 1123 K, followed by slow cooling. These chalcogenides are isostructural, adopting the space group Pbam (Z = 2), with lattice dimensions of a = 9.6560(6) ?, b = 14.0533(9) ?, c = 4.3524(3) ?, and V = 590.61(7) ?(3) in the case of Ba(2)Cu(5.53(3))STe(4). A significant phase width was observed in the case of Ba(2)Cu(6-x)Se(y)Te(5-y) with at least 0.17(3) ≤ x ≤ 0.57(4) and 0.48(1) ≤ y ≤ 1.92(4). The presence of either S or Se in addition to Te appears to be required for the formation of these materials. In the structure of Ba(2)Cu(6-x)STe(4), Cu-Te chains running along the c axis are interconnected via bridging S atoms to infinite layers parallel to the a,c plane. These layers alternate with the Ba atoms along the b axis. All Cu sites exhibit deficiencies of up to 26%. Depending on y in Ba(2)Cu(6-x)Se(y)Te(5-y), the bridging atom is either a Se atom or a Se/Te mixture when y ≤ 1, and the Te atoms of the Cu-Te chains are partially replaced by Se when y > 1. All atoms are in their most common oxidation states: Ba(2+), Cu(+), S(2-), Se(2-), and Te(2-). Without Cu deficiencies, these chalcogenides were computed to be small gap semiconductors; the Cu deficiencies lead to p-doped semiconducting properties, as experimentally observed on selected samples.     

Fabrication of nanoreactors based on polyoxoperoxometalates and enhancement of their catalytic activity

The nanoreactors were fabricated by reacting amphiphilic quaternary ammoniums and polyoxoperoxometalates K_n[PW_12-xTi_x- O_40-x（O₂）_x]（x=1,2 and 3;n = 5,7 and 9）(K₅[PW₁₁TiO₃₉（O₂）],K₇[PW₁₀Ti₂O₃₈（O₂）₂]and K₉[PW₉Ti₃O₃₇（O₂）₃]).Fourier transform infrared spectroscopy（FT-IR）,transmission electron microscopy（TEM） were used to characterize the resulting samples. This kind of nanocatalysts could promote NH₄SCN’ degradation into simple inorganic compounds such as SO₄^2-,HCO₃^- and NO₃^- only using oxygen as an oxidant under room conditions.     

STUDIES ON TiCI4/Mg (OEt)_2/EB SUPPORTED CATALYSTS FOR PROPYLENE POLYMERIZATION

The supported catalysts for propylene polymerization were prepared by milling Mg (OEt)_2 with EB (ethylbenzoate) and treating with TiCl_4 solution. When TiCl_4/(Mg(OEt)_2/EB) (mol.) ratio was increased, decrease in contents of-OEt and Ti of the catalysts was observed, while the content of EB increased. It is proved by analyses of IR, X-ray and XPS that during co-milling Mg(OEt)_2 with EB no reactions have taken place. But after treatment with TiCl_4 solution, Mg(OEt)_2 converts into MgCl_2 and EB coordinates on the resulting MgCl_2 carrier, a surface complex forms.The activity of catalysts,isotacticity and vicosimetric molecular weight of polypropylene increase with the decrease of the content of ethoxyl group. The kinetic curves of propene polymerization obtained with present catalysts system display decay curves. It is found from the triad tacticity calculated from the expanded spectra of methyl carbon region that, ethoxyl group in catalyst has an effect on the configuration of polymer chain.     

Local structural distortion of BaZr(x)Ti(1-x)O3 nanocrystals synthesized at room temperature

Single crystalline, sub-15 nm BaZr(x)Ti(1-x)O(3) (0 ≤x≤ 1) nanocrystals were synthesized at room temperature via the vapor diffusion sol-gel method. As-prepared nanocrystals exhibit noncentrosymmetric regions whose volume fraction increases significantly upon substitution of small amounts of Zr(4+) for Ti(4+) and reaches a maximum for substitution levels ranging from 10 to 20 mol%.     

氧化铝对Pt-SO4^2-／ZrO2-Al2O3固体酸催化剂结构与酸性的影响

通过混捏法制备了Pt-SO4^2-／ZrO2-Al2O3固体酸催化剂，考察了该催化剂在正构烷烃低温异构化反应中的催化稳定性．采用X射线衍射、差热分析、X射线光电子能谱、核磁共振、N2吸附-脱附和微量热等表征技术，对氧化铝的作用机理进行了研究．结果表明，氧化铝起到结构助催化剂作用，对四方相氧化锆具有稳定作用，并延迟了氧化锆的晶化，抑制了氧化锆的烧结，从而增大了催化剂的比表面积和孔容．XPS结果表明，Zr3d峰向低结合能方向移动，Al2p峰向高结合能方向移动，说明Al^3＋的电子向Zr^4＋偏移．微量热结果表明氧化铝的引入提高了催化剂的酸量和酸强度．^27Al固体核磁共振结果表明，Pt-SO4^2-／ZrO2-Al2O3中的六配位铝的结构发生了变化．氧化铝的引入还可能有助于氧化锆晶格缺陷的形成，焙烧过程中Al^3＋迁移进入氧化锆晶格并同晶取代Zr^4＋形成氧缺陷位，这些氧缺陷位在S=O键诱导下显示强酸性．     

Catalytic hydrolysis of CFC-12 over solid acid Ti(SO_4)_2

Due to increasing enthusiasm for environmental preservation, the synthesis ofchlorofluorocarbons (CFCs) alternatives and the decomposition of existing CFCs havebeen two hot topics since the production and utilization of CFCs are banned by manycountries. The former has been well carried out while the latter was rarely reported inChina. Among a dozen of decomposition approaches. catalytic hydrolysis is verypromising because of simple processes, requiring mild conditions, dioxins free and the…