Magnetoresistance of FexNi80-xCr20 (50alloys

The authors have measured longitudinal and transverse magnetoresistance (MR) of crystalline pseudo-binary alloys FexNi80-xCr20 (50alloys have compositions close to the critical composition regime for ferromagnetism. While the Fe-Ni-Cr alloys have a FCC gamma -phase, the binary Fe-Cr alloy has a BCC alpha -phase. This gives an opportunity to compare magnetoresistances for gamma -phase and alpha -phase Fe alloys when they lie close to the critical composition. The experiments were conducted at 4.2 K with magnetic fields up to 7 T. The authors observed that all the alloys show negative magnetoresistance at 4.2 K in fields up to 7 T. However, for the gamma -phase alloys the typical maximum MR ( Delta rho / rho ) is about 1%, while for the alpha -phase alloy it is 10%. In the gamma -phase alloys there is a small but finite anisotropy of MR in the phases with long-range magnetic order which gradually vanishes near the critical region (x=xc approximately=59-63) when it becomes a spin glass. In the range x approximately=xc, Delta rho / rho varies as Mn (M=magnetization) with n approximately=2.

Characterization of electrochemically deposited Cu-Ni black coatings

Electrochemically deposited Cu-Ni black coatings on molybdenum substrate from ethylenediaminetetraacetic acid (EDTA) bath solution are shown to exhibit good optical properties (alpha = 0.94, epsilon = 0.09). The deposit is characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Cu is present in metallic and +2 oxidation states in the as-prepared Cu-Ni black coating, whereas Ni2+ as well as Ni3+ species are observed in the same coating. Cu and Ni are observed in their metallic state after 10 and 20 min sputtering. X-ray initiated Auger electron spectroscopy (XAES) of Cu and Ni also agrees well with XPS investigations. (C) 2002 Elsevier Science Ltd. All rights reserved.

Three phase equilibria for activity determinations: system Co Mn

A solid state e.m.f. cell with yttria-doped thoria as the electrolyte and a mixture of Cr + Cr sub 2 O sub 3 as the reference electrode, was employed for the measurement of the activity of manganese in the Co--Mn system at 1760 deg K, for 0.3 > X sub Mn > 0.05. The liquid alloy was contained in an alumina crucible and saturated with MnAl sub 2+2x O sub 4+3x . The cell can be represented by Pt, W, (Co--Mn) + MnAl sub 2+2x O sub 4+3x + Al sub 2 O sub 3 /ThO sub 2 --Y sub 2 O sub 3 /Cr + Cr sub 2 O sub 3 , Pt. The activity of manganese shows negative deviations from Raoult's law. The activities in the Co--Mn system are intermediate between those in the Fe--Mn and Ni--Mn systems. The Gibbs' energies of mixing in these systems follow the trends given by Miedema's model. 14 ref.--AA.

Hot deformation behavior of Ni-Fe-Ga-based ferromagnetic shape memory alloy - A study using processing map

Ni-Fe-Ga-based alloys form a new class of ferromagnetic shape memory alloys (FSMAs) that show considerable formability because of the presence of a disordered fcc gamma-phase. The current study explores the deformation processing of this alloy using an off-stoichiometric Ni55Fe59Ga26 alloy that contains the ductile gamma-phase. The hot deformation behavior of this alloy has been characterized on the basis of its flow stress variation obtained by isothermal constant true strain rate compression tests in the 1123-1323 K temperature range and strain rate range of 10(-3)-10 s(-1) and using a combination of constitutive modeling and processing map. The dynamic recrystallization (DRX) regime for thermomechanical processing has been identified for this Heusler alloy on the basis of the processing maps and the deformed microstructures. This alloy also shows evidence of dynamic strain-aging (DSA) effect which has not been reported so far for any Heusler FSMAs. Similar effect is also noticed in a Ni-Mn-Ga-based Heusler alloy which is devoid of any gamma-phase. (C) 2014 Elsevier Ltd. All rights reserved.

Graphene as a diffusion barrier for isomorphous systems: Cu-Ni system

Electrochemical exfoliation technique using the pyrophosphate anion derived from tetra sodium pyrophosphate was employed to produce graphene. As-synthesized graphene was then drop dried over a cold rolled Cu sheet. Ni coating was then electrodeposited over bare Cu and graphene-Cu substrates. Both substrates were then isothermally annealed at 800 degrees C for 3 h. WDS analysis showed substantial atomic diffusion in annealed Ni-Cu sample. Cu-graphene-Ni sample, on the other hand, showed negligible diffusion illustrating the diffusion barrier property of the graphene coating. (C) 2016 Elsevier B.V. All rights reserved.

Graphene as a diffusion barrier for isomorphous systems: Cu-Ni system

Electrochemical exfoliation technique using the pyrophosphate anion derived from tetra sodium pyrophosphate was employed to produce graphene. As-synthesized graphene was then drop dried over a cold rolled Cu sheet. Ni coating was then electrodeposited over bare Cu and graphene-Cu substrates. Both substrates were then isothermally annealed at 800 degrees C for 3 h. WDS analysis showed substantial atomic diffusion in annealed Ni-Cu sample. Cu-graphene-Ni sample, on the other hand, showed negligible diffusion illustrating the diffusion barrier property of the graphene coating. (C) 2016 Elsevier B.V. All rights reserved.

Localized Solid-State Amorphization at Grain Boundaries in a Nanocrystalline Al Solid Solution Subjected to Surface Mechanical Attrition

Using high-resolution electron microscopy, localized solid-state amorphization (SSA) was observed in a nanocrystalline (NC) Al solid solution (weight per cent 4.2 Cu, 0.3 Mn, the rest being Al) subjected to a surface mechanical attrition treatment. It was found that the deformation-induced SSA may occur at the grain boundary (GB) where either the high density dislocations or dislocation complexes are present. It is suggested that lattice instability due to elastic distortion within the dislocation core region plays a significant role in the initiation of the localized SSA at defective sites. Meanwhile, the GB of severely deformed NC grains exhibits a continuously varying atomic structure in such a way that while most of the GB is ordered but reveals corrugated configurations, localized amorphization may occur along the same GB.

Effect of Carbon Addition on Microstructure and Mechanical Properties of Ti-Based Bulk Metallic Glass Forming Alloys

A kind of novel Ti-based composites was developed by introducing different amounts of carbon element to the Ti-50 Cu-23 Ni-20 Sn-7 bulk metallic glass forming alloys. The thermal stability and microstructural evolution of the composites were investigated. Room temperature compression tests reveal that the composite samples with 1% and 3% (mass fraction) carbon additions have higher fracture strength and obvious plastic strain of 2 195 MPa, 3.1% and 1 913 MPa, 1.3% respectively, compared with those of the corresponding carbon-free Ti-50 Ni-20 Cu-23 Sn-7 alloys. The deformation mechanisms of the composites with improved mechanical properties were also discussed.

Síntese, caracterização e aplicações na desidrogenação oxidativa de propano de materiais tipo hidrotalcita Ni-Mg-Al com diferentes ânions de compensação

Na reação de desidrogenação oxidativa de propano (ODHP), propano reage com oxigênio da superfície de metais de transição para produzir propeno e água, em temperaturas de 300-700C. Porém, o propeno pode facilmente oxidar, formando CO e CO2. Assim, busca-se catalisadores que promovam a seletividade do propeno. Compostos tipo hidrotalcitas estão sendo apontados como catalisadores de grande potencial para a reação. Portanto, o principal objetivo desse trabalho foi sintetizar precursores tipo hidrotalcitas (contendo íons Ni2+, Mg2+ e Al3+ e tereftalato, heptamolibdato e decavanadato como ânions de compensação) para serem testados na reação de desidrogenação oxidativa de propano. Esses precursores foram sintetizados com uma razão Al/(Al+Ni+Mg)=0,5, variando a razão de Ni/Mg. Além disso, realizou-se a troca iônica do tereftalato (TA) por heptamolibdato (Mo7O24) e decavanadato (V10O28). Esses compostos foram calcinados, obtendo-se assim, óxidos mistos de NiMgAl, NiMgAlMo e NiMgAlV que foram testados como catalisadores na reação de ODHP. Para a determinação das propriedades dos catalisadores foram usadas as técnicas de caracterização: DRX, TGA, volumetria de N2, TPR, Raman e FTIR e ICP. Os resultados indicaram que os materiais tipo hidrotalcita foram obtidos com sucesso. No caso dos precursores preparados por troca iônica a cristalinidade foi menor que os da série NiMgAl-TA. Estes mesmos precursores quando calcinados apresentaram áreas muito altas. Nas três séries, os precursores calcinados são constituídos por óxidos mistos como NiO, NiMoO4, Ni2V2O7 cristalinos e espécies de alumínio e magnésio não detectados na DRX. No teste catalítico de ODHP, observou-se que com o aumento da conversão diminuía a seletividade de propeno, para os óxidos mistos que não continham molibdênio. Os catalisadores da série molibdênio foram os que obtiveram melhor desempenho com altas seletividades, mesmo em altas conversões e a série de cujo precursor foi o tereftalato foi a que exibiu maiores conversões, mas com seletividades menores que da série de Mo

催化消除NO_x复合氧化物催化剂的研究

氮的氧化物(NOx)是大气中的一种重要的污染物，是酸雨的主要来源，目前氮氧化物的无毒处理已经是国际环保研究中最关键的课题之一。本论文选择了两种复合氧化物：一种是钙钛石结构的含Cu的层状复合氧化物；另一种是以水滑石为前体经焙烧后得的复合氧化物为催化剂对它们的物化性质和对催化消除NOx的活性进行了系统的研究，得到了一些有意义的结果。第一部分：钙钛石型结构的含Cu层状复合氧化物钙钛石复合氧化物由于具有独特的物理化学性质，长期以来一直受到固态物理、固体化学和催化领域的科技工作者的重视。尤其近年来对它们在催化消除NOx反应中的活性的研究引起了催化工作者的极大兴趣，这是由于，一方面，钙钛石类复合氧化物对处理NOx的反应活性比较高，有希望取代贵金属催化剂；另一方面，探讨复合氧化物的固态物理、化学性质与处理NOx反应催化性能的关系，有利于揭示处理NOx反应的催化作用本质，为寻找高效实用的催化剂提供理论依据。本论文系统研究了三个系列含Cu钙钛石型复合氧化物的固态物理化学性质和对NO-CO反应的催化性能，并讨论了二者的关系。主要的工作和结论如下：1) 以La_2CuO_4为模型化合物研究了制备方法对它的性质的影响：用四种制备方法：柠檬酸络合爆炸法，聚乙二醇凝胶法，聚丙烯酰胺凝胶法，DTPA络合法合成了La_2CuO_4。比较了四种方法的特点，和制备方法对La_2Cu0_4的结构的影响，并对所得La_2CuO_4在NO-CO反应中的催化活性的影响进行了研究。结果发现聚乙二醇凝胶法和DTPA络合法有利于形成好的晶形，而聚乙二醇凝胶法和聚丙烯酰胺凝胶法对NO-CO反应有较好的活性，这是由于由不同制备方法得到的样品中的缺陷的种类和含量不I司所致。2) La_(1-x)Ba_xCuO_(3-λ)系列中Ba含量对它的性质的影响：用柠檬酸络合法合成了LaBa_2Cu_3O_(7-λ)，LaBaCu_2O_(5-λ)，La_2BaCu_3O_(7-λ) La_4BaCu_5O_(13-λ)及YBa_2Cu_3O_(7-λ)五种钙钛石结构的复合氧化物。XRD分析表明此系列样品均为层状ABO_3结构（分别为二，三，五层）。用XPS和O_2-TPD对样品中的氧种进行了研究，结果显示样品中存在着两种活性氧种：α氧种和β氧种。在O_2-TPD中低温脱附的是α氧种，它可归属于化学吸附氧与样品中的氧空位的浓度有关。β氧种的脱附温度较高，它归属于晶格氧。利用H_2-TPR和化学分析的手段对样品中的金属离子和活性氧的稳定性进行了表征。结果显示大量的氧空位和Cu~(3+)存在于样品中，并且它们的浓度受Ba离子浓度的影响。此系列样品对CO还原NO的活性研究表明：它们的活性远远高于结构类似的Ln_2CuO_4和Ln_2NiO_4等复合氧化物，在低于300 ℃时N0转化率已接近100％．分析结果表明Cu~(3+)和氧空位对活性起很重要的作用。Ba离子的作用是：一方面使含Cu的ABO_3结构稳定；另一方面使样品更容易吸附NO。3) La_4BaCu_5O_(13-λ)中Mn或C0逐步取代Cu对样品性质的影响合成了两系列分别由Mn或Co逐步取代Cu的样品，XRD分析表明它们仍旧是钙钛石结构。通过XPS，O_2-TPD和化学分析方法对样品中的活性氧种进行了表征，结果表明，当Mn逐步取代Cu离子时，晶格氧增加，而吸附氧开始变化较小，当Mn含量大于Cu含量时，吸附氧迅速减少。在Co取代样品的O_(1s)的XPS谱中，氧种变化较Mn取代的小，这表明Co离子对样品中的氧空位含量的影响较Mn离子的小。氧化还原性能的研究表明当Cu离子被Mn或Co离子部分取代后，Cu离子变得更容易被还原，这表明Cu-M(Mn或CO)之间发生了协同作用，使Cu离子更活泼。当Mn或Co部分取代Cu离子之后，样品对CO还原NO反应的催化活性明显提高，当取代含量达到一定程度时（即X ≥ 3），催化活性迅速降低，这表明Cu离子在反应中起着很重要的作用，经过分析我们认为反应机理如下：Cu~(3+)-O~=-Cu~(3+) + CO → Cu~(2+)-□-Cu~(2+)+CO_2 Cu~(2+)-□-Cu~(2+) → Cu~(3+)-□-Cu~(2+) Cu~(3+)-□-Cu~(2+) + NO~-Cu~(3+)-NO-Cu~(2+) 2Cu~(3+)-NO-Cu~(2+) → 2Cu~(3+)-O~=-Cu~(3+) + N_2 式中□是氧空位，Cu~(3+)-□ 是F心。掺杂部分Mn或Co后，催化活性的提高可以归属于Cu-M之间发生的协同作用使Cu离子更活泼，表征结果表明Cu-Co之间的协同作用较Cu-Mn之间的弱（这可能是由于Co，Cu之间化学性质相似），但掺杂Co的样品的活性较掺杂Mn的要高，同时我们在反应中发现，Co含量较高的样品中反应产物中N_2O比掺杂Mn的样品高出许多，因此我们认为Co离子对反应中反应中间产物N_2O的生成比Mn离子要活性。第二部分以水滑石化合物为前体的复合氧化物水滑石类化合物属于一种阴离子粘土，由带正电荷的金属氧化物／氢氧化物和层间阴离子及水分子组成。以水滑石为母体经焙烧制得的氧化物催化剂用于氧化反应的实例尚不多，且大多用于液相催化反应。最近有文献报道含Co，Cu，Ni水滑石经焙烧后对N_2O分解有很好的活性，但还没有关于此类化合物应用于NO还原和分解的文献报道。我们首次将以水滑石为母体经焙烧制得的尖晶石催化剂用于催化消除NO_x的反应中，考察和表征了变更过渡金属离子时Co-M-Al系列和Mg-M-Al系列催化剂在CO还原NO，NO吸附和NO分解反应中的活性。1) 以Mg-M-Al水滑石为前体的催化剂用共沉淀法合成了一系列Mg-M-Al水滑石（M = Cr，Fe，Mn，Co，Ni，Cu；Mg/M/A1 = 3/1/1）。XRD表征表明所有化合物均为典型的水滑石化合物。通过TG-DTA考察了焙烧对样品的结构和组成的影响。450 ℃焙烧后所有样品的XRD图中仅能发现MgO相，表明过渡金属氧化物均匀地分散在MgO-Al_2O_3中，换句话说，所得样品焙烧后是过渡金属氧化物负载在MgO-Al_2O_3载体上。H_2-TPR研究进一步证实过渡金属氧化物在载体上得到了稳定。此系列样品对C0还原N0反应活性的测定表明Mg-Al-Cu样品表现出远远高于其它样品的活性，而Mg-Al和Mg-Ni-Al在550 ℃以下对反应几乎没有活性，其它样品表现出一定的活性。2) 以Co-M-Al水滑石为前体的催化剂体系经共沉淀法合成了Co-M-Al水滑石（M = 过渡金属），经焙烧后发现样品中有尖晶石相出现。比表面研究表明，在500-700 ℃之间比表面变化较小大约在80m~2/g左右，在更高温度焙烧后比表面迅速下降。此系列样品对NO的吸附性能研究表明Co-Al，C0-Ni-Al，Co-Cr-Al，Co-Fe-Al表现出较高的吸附性能，尤其是Co-Ni-Al在100 ℃对NO表现出100％的吸附；其它样品对NO的吸附较低。用过渡金属离子中d轨道电子在吸附前后的晶体场稳定化能的变化可以很好地解释此系列样品对NO的吸附性能。对NO分解的活性测定表明Co-Ni-A1，Co-Cr-A1和Co-Al表现出了较好的活性，其中Co-Ni-Al的活性最高。其它样品在600 ℃以下几乎没有活性。分析结果表明样品对NO分解有活性的催化剂必须具备两个条件：1：对NO有较好的吸附性能；2: NO分解后产生的氧可以容易的脱附。除Co-Al外，所有样品对CO还原NO表现出很高的活性：在150 ℃即有较高的NO转化率，在180 ℃NO转化率即可达到100％。催化剂的氧化还原性能在反应中起着很重要的作用，H_2-TPR研究发现掺杂其它过渡金属后Co离子的还原温度明显降低，表明Co离子得到了活化。3) 以Co-Cu-Al水滑石为前体的样品用共沉淀法合成了一系列Co/Cu/Al含量不同的水滑石化合物，包括Co/Cu/Al分别为7/1/1，3/1/1及1/1/1和仅含Co或Cu的Co/Al = 3/1，Cu/Al = 3/1等一系列样品。XRD结果表明除Cu-Al外其它样品经焙烧后均出现了尖晶石相。Cu-Al样品经焙烧后出现了CuO相表明样品为CuO负载于Al_2O_3上。NO和CO的TPD研究表明三组份样品对NO和CO的吸附明显高于二组份样品，而且含CO量高的样品对NO和CO的吸附能力更好，表明Co起较强的作用。在三组份样品的NO-TPD脱出物中发现有N_2O和N_2，表明NO在样品表面的吸附为活化吸附。对CO还原NO反应活性的研究表明，三组份样品的活性远远高于二组份样品，且含Co量高的样品活性较高，表明在此系列样品中Co离子起决定性作用，而Cu离子起助催化作用。通过对反应中各组份含量的变化分析，我们认为反应机理如下：CO + O-Cat → CO_2 + □-Cat NO + □-Cat → NO-Cat 2(NO-Cat) → N_2O + O-Cat + □-Cat N_2O + □-Cat → N_2O-Cat N_2_O-Cat → N_2 + O-Cat 2(N_2O-Cat) → N_2 + 2(O-Cat) O-Cat是样品中的晶格氧，在Co-Al中加入其它过渡金属离子使样品中的晶格氧得到活化，因此，催化活性得到提高。用以水滑石为前体，共沉淀法和固相反应法等三种制备方法合成了一系列Co-Cu-Al催化剂，发现以水滑石为前体的样品不论是对NO，CO的吸附性能还是对NO-CO反应的催化活性都远远高于其它方法制备的样品，这可能是由于水滑石可以起到一个模版作用，使Cu, Co离子分散的更均匀，以及使催化剂表面的含氧基团丰富。

镍-金属氢化物电池新型负极材料研究

贮氢合金是镍一金属氢化物电池的核心材料，其综合性能的改善是提高镍一金属氢化物电池性能的关键。本研究以探索镍一金属氢化物电池新型负极材料为目的，以非ABS型贮氢合金为研究对象，采用X射线衍射、Rietveld分析、恒电流充／放电、P-C-T曲线及线性微极化等方法，从基础和潜在应用等方面详细研究了非ABS型合金的结构与电化学性能。对La-Ni体系中非ABS型二元合金的结构和电化学性能的研究表明，LaNi_(228)具有最优异的高倍率充电性能；La_2Ni_7合金电极的高倍率放电性能最佳；La_7Ni_3在低温条件下表现出较好的放电性能。然而，所有得到的La-Ni合金电极容量远低于其理论容量。因此，必须通过进一步研究，如元素取代、热处理、表面处理等来提高其电化学容量。对RENi_3（RE＝La，Ce，Pr，Nd，Sm，Gd，Th，Dy，Ho，Er，Y）研究表明：YNi_3合金因其具有最大的晶胞体积，最小的密度，而表现出最好的高倍率充／放电性能及低温放电性能，但其高温放电性能需要进一步提高，以满足实际应用的要求。用Al、Mn、Ti、Fe、Sn、Si、Cr、M。、Cu和Co十种元素取代Ni进行了大量的配方筛选工作。得到了大量的实验数据，并发现LaNi_(3.7)Al_(0.3)合金电极电化学放电容量最高，达290.8mAh／g；LaNi_(3.7)Mo_(0.3)合金电极的高倍率放电性能最好，在以4200mA/g的电流密度下进行放电时，其放电容量仍达到145.8mA/g；而I镍一金属氢化物电池新型负极材料研究镍一金属氢化物电池新型负极材料的研究Al的取代会使合金电极性能对温度不敏感。以我们的实验为基础，进一步进行合金配方的微调，具有可能开发出具有实用价值的贮氢合金的潜力。在Ar保护下用真空电弧炉熔炼合成了四种Lal一xMg：（NICoAI）3．6体系贮氢合金，制成姐卜Ni电池负极，通过恒电流充／放电方法研究了其电化学性能。结果表明：Lal一xMg：（NiCoAI）3．6体系金属氢化物电极较容易活化，室温下具有优异的高倍率放电性能，在以4200mA／g电流放电时，La卜汉gx（NICoAI）36合金电极的放电容量是ABS型合金电极的3倍，达152hah／g，显示出良好的动力学特性。R，入1兮Ni（R：raree田劝，Ca，Y）型合金因能吸引／释放1．8一1．87％质量的HZ而被认为是种很有希望的贮氢合金。但其吸／放氢平台过高，循环寿命短。如何提高Rh厦g剑19循环稳定性是这类合金能否成功商业化的关键。研究发现，Co能够显著提高ABS型合金电极的循环寿命，但其价格太贵。人们发现Al在提高电极寿命方面与C。有类似的作用，但Al元素的添加因其在碱性电解质的作用下在电极表面易生成致密的氧化膜而不利于氢的扩散，进而对高倍率放电性能不利。入物在提高电极表面活性，改善其高倍率放电性方面作用明显。本工作在前面的基础上用Al和MO联合取代Ni，以期待同时改善La一Mg一Ni一Co合金的循环稳定性和高倍率放电性能。详细研究了La07Mg03Ni切一（A105Mo05）x（x：o，0．2，0．4，0．6，0．8）系列贮氢合金的晶体结构和电化学性能。X射线衍射及Rietveld分析发现：所有La07Mg03Ni4D一x（A105Mo05）x合金均为包含PuNi3结构的六方LaZMgNig相、CaCus结构的LaNis主相及L匆Ni7，LaN儿和LaNi杂相的多相结构。合金中La（La，Mg）剑19相及LaNis相的晶格参数及晶胞体积均随合金中Al和Mo含量的增加而增大。用电化学方法测得的RC一T曲线显示：Al和'fo部分取代Ni降低了氢的平台压力。随合金中Al和Mo含量的增加，电极的电化学容量从329．7（x＝0）、徽橇毓孺鑫盆一11瀚加至365．物A吨（＝0．6）后又降低到351．3毗吨（x＝0．8）。当以1200m刀g的电流密度进行放电时，其I｛RD从62．0％沁0）增加到82．1％沁0．8）。线性微极化结果显示：Al和Mo的添加增大了合金表面的交换电流密度，因而也改善了合金电极的高倍率放电性能。另外，Al和M。取代合金中的Ni增大了氢在电极合金中的扩散系数（D），改善了La07Mgo3Ni4。一x（Alo5M。。5）x（X＝o，0．2，0．4，0．6，0．8）合金电极的低温放电性能（LTD）。

川西地区几种优势苔藓植株元素含量及其时空差异性

揭示苔藓植株元素含量及其时空差异性是深入开展利用苔藓植物指示环境和筛选理想监测藓种的科学基础。采用微波消解（ICP-AES）方法对九寨沟自然遗产地原始林景点停车场周围三个采样带：I为停车场植被小岛（PS），向外约120 m半径为II带（D120），再向外距离约1,000 m为III带（D1000）和3个方向上的大羽藓和毛尖青藓2种苔藓中13种元素（A1, S, Ca, P, Cu, Fe, K, Mg, Mn, Pb, Ni,Zn和Cd）含量进行了测定和比较，并对采自边坡方向（PS-3）上2005和2007年的4种苔藓植物（南木藓、大羽藓、平藓和厚角絹藓）也进行了13种元素含量的测定和比较。同时对九寨沟自然遗产地、黄龙自然遗产地、夹金山和梦笔山的冷杉原始林4个地区的3种苔藓中（大羽藓、锦丝藓和塔藓）的A1、Ca、Cu、Fe、K、Mg、P、Zn、C和N 10种元素含量进行测定和比较。 对大羽藓和毛尖青藓2种苔藓植物内13种元素的测定发现：1）同种苔藓对不同元素的富集能力不同。A1、Ca、K、Mg和P的元素含量在苔藓中的富集较其他元素的要高。2）不同种苔藓植物对同种元素的富集能力不同，毛尖青藓较大羽藓能够监测出更多的元素；对于被检测出的元素，毛尖青藓监测出的累积量大于大羽藓，其中累积量最大的元素是Ca为10 874.286 μg.g-1.year-1，最小的是Cu元素为5.438 μg.g-1.year-1。对05年和07年的平藓、大羽藓、南木藓和厚角絹藓元素含量的测定表明：元素在两年中的积累量是不同的。综合分析表明，苔藓生物监测方法可有效监测景点停车场机动车尾气中排放出的典型元素（如Cu、Pb、Ni、Zn、Cd等）含量，而毛尖青藓较大羽藓能更可靠的监测九寨沟自然遗产地单景点汽车尾气金属元素种类及其排放量。 对4个地区3种苔藓10种元素监测发现：1）Ca、Mg、Zn、K和Cu元素在黄龙地区的含量高于在其它地区的含量；P元素在梦笔山地区的含量为最高；Fe和Al元素在夹金山地区的含量高于在其它地区的含量。2）C元素在其它因素一致的情况下，进行不同年龄间的元素含量比较，结果显示元素含量在各年龄间并不存在明显的差异性；N元素含量与年龄的差异出现在黄龙林下及林窗的塔藓、九寨沟林下的锦丝藓及塔藓和梦笔山的塔藓中，而在锦丝藓中未出现元素含量与年龄的差异性；塔藓能检测出更多的元素种类其含量与年龄间存在显著差异，锦丝藓检测到的元素种类次之；除锦丝藓（锦丝藓在林窗中几乎检测不到元素含量与年龄间的差异性）外，其他两种藓在林窗中能检测出的元素种类大于在林下的检测种类。3）元素含量与生境间存在差异性的元素分别有：黄龙大羽藓中的Ca、P和Mg元素；九寨锦丝藓中的Zn元素；夹金山塔藓中的Al、Fe和Zn元素；梦笔山大羽藓中的Al、Fe和Mg元素及锦丝藓中的Ca元素。4）区域、年龄和生境因素对苔藓植株元素含量均达到了显著水平，但两两之间及三者之间的交互作用由于元素种类的不同存在差异。综合分析表明，苔藓植物中的元素含量受年龄、区域的影响较生境的更大。 The revelation of mosses elements content and its spatiotemporal differences is the scientific foundation of moss monitoring. To determine the feasibility of moss monitoring metal depositions derived from travel bus emiss ions in scenic spot, we collected one year-growth samples of two mosses Brachythecim piligerum and Thuidium cymbifolium with different distance (island center, 120m，1000m ) and different direction (north, south and east) far from parking site island from Yuanshilin Spot at Jiuzhaigou World Nature Heritage in the Western Sichuan of China and determined thirteen element （A1, S, Ca, P, Cu, Fe, K, Mg, Mn, Pb, Ni, Zn, Cd）contents by ICP-AES analysis method. And picked 4 kinds of mosses (Macrothamnium macrocarpu m（Reinw. etHornsch.）Fleisch.，Thuidium cymbifolium，Entodon concinnus (De Not.) Par., Neckera pennata) from the direction PS-3 in 2005 and 2007, determined 13 element contents. Collected 3 kinds of moss (Thuidium cymbifo lium, Actinothuidium Hookeri (Mitt.) and Hyolcomium splendens (Hedw.) from Jiuzhaigou natural heritage, Huanglong natural heritage, Mt. Jiajin and Mt. Mengbi in primeval forest with two habitat (undergrowth and forest gap), determined element contents of A1, Ca, Cu, Fe, K, Mg, P, Zn, C and N. We found that, 1) The elements content are difference in same type of moss. Content of A1, Ca, K, Mg and P are higher than others. 2) While the contents of A1, S, Ca, P, Cu, Fe, K and Zn had significant correlation with the different distances from parking site, the nearer the distance was, the more accumulation was; 2) Comparing to Thuidium cymbifolium, Brachythecium piligerum can test more elements which contents show the significant correlation with distances. And Brachythecium piligerum can have greater element accumulation than Thuidium cymbifolium. The element contents in two years (2005 and 2007) are different. The present study found that moss can reliably bio-indicate metal deposition from traffic emissions in one scenic spot and Brachythecium piligerum is a good moss for bio-indicating element content from traffic emissions at Jiuzhaigou World natural Heritage. Determined the 10 element contents in 4 areas through 3 kinds of moss we found that, 1) Ca, Mg, Zn, K and Cu element content is higher in the Huanglong area than in other areas, The P element content in Mt. Jiajin is higher than other areas, Fe and Al element content is higher in the Mt. Jiajin than in other areas. 2) The content of C had no significant correlation with age. As for N, this significant correlation found in Hyolcomium splendens (Hedw.) with 2 habitat in Huanglong, Actinothuidium Hookeri (Mitt.) and Hyolcomium splendens (Hedw.) with undergrowth in Jiuzhai, Hyolcomium splendens (Hedw.) in Mt. Mengbi. The types of elements which content showt he significant correlation are most in Hyolcomium splendens (Hedw.) and least in Thuidium cymbifolium. Except Actinothuidium Hookeri (Mitt.), the types of elements that content had significant correlation with age in forest gap are more than in undergrowth. 3) The elements which content had significant correlation with habitat are P, Ca and Mg in Thuidium cymbifolium in Huanglong, Zn in Actinothuidium Hookeri (Mitt.) in Jiuzhai, Al, Fe and Zn in Hyolcomium splendens (Hedw.) in Mt. Jiajin, in Mt. Mengbi Al, Fe and Mg in Thuidium cymbifolium and Ca in Actinothuidium Hookeri (Mitt.). 4）The region, the age and the habitat factor has coeffect element content. The correlationship between element contents and the age, the region is closer than habitat.

High strength Ni based composite reinforced by solid solution W(Al) obtained by powder metallurgy

The solid-solution-particle reinforced W(Al)-Ni composites were successfully fabricated by using mechanical alloying (MA) and hot-pressing (HP) technique when the content of Ni is between 45 wt% and 55 wt%. Besides, samples of various original component ratio of Al50W50 to Ni have been fabricated, and the corresponding microcomponents and mechanical properties such as microhardness, ultimate tensile strength and elongation were characterized and discussed. The optimum ultimate tensile strength under the experiment conditions is 1868 MPa with elongation of 10.21 % and hardness of 6.62 GPa. X-ray diffraction (XRD), FE-SEM and energy dispersive analysis of X-rays (EDS) were given to analysis the components and morphology of the composite bulk specimens.

Synthesis, crystal structure, and magnetic properties of {[Cu(oxbe)]Mn(H2O)[Cu(oxbe)(DMF)]}(n)center dot nDMF center dot nH(2)O: From dissymmetrical mononuclear entities to a 3D heterometallic supramolecular coordination polymer

Self-assembly of the building block [Cu(oxbe)](-) with Mn(II) led to a novel coordination polymer {[Cu(oxbe)]Mn(H2O)(Cu(oxbe)(DMF)]}(n).nDMF.nH(2)O, where H(3)oxbe is a new dissymmetrical ligand N-benzoato-N'-(2-aminoethyl)-oxamido and DMF = dimethylformamide. The crystal forms in the triclinic system, space group P(1)over-bar, with a = 9.260(4) angstorm, b = 12.833(5) angstrom, c = 15.274(6) angstrom , alpha = 76.18(3)degrees, beta = 82.7(3)degrees, gamma = 82.31(3)degrees, and Z = 2. The crystal structure of the title complex reveals that the two-dimensional bimetallic layers are constructed of (CuMnII)-Mn-II-Cu-II chains linked together by carboxylate bridge and hydrogen bonds help to produce a novel three-dimensional channel-like structure. The magnetic susceptibility measurements (5-300 K) were analyzed by means of the Hamiltonian (H)over-cap = -2J(S)over-cap (Mn)((S)over-cap(Cu1) + (S)over-cap(Cu2)), leading to J = -17.4 cm(-1).

添加元素对AB_2型Laves相合金电化学性能的影响

比较系统地研究了 AB2 型 Laves相合金 Zr0 .9Ti0 .1Ni0 .1Mn0 .7V0 .3 M0 .1( M=None,Ni,Mn,V,Co,Cr,Al,Fe,Mo,Si,C,Zn,Cu和 B)的相结构和电化学性能以及高温和低温放电性能等 .结果表明 ,1 4种合金均具有六方 C1 4型 Laves相的主相晶体结构 ,同时 ,含有少量立方 C1 5型 Laves相和一些由 Zr.9Ni11及 Zr Ni组成的非 Laves相 ;添加 V和 Mn可提高 AB2 合金的放电容量 ;添加 B和 Mn则显著提高了 AB2 合金的高倍率放电性能和低温放电容量 ;添加 Al,C,Si和 Co对合金电极的循环稳定性改善明显 ;而 Mn,Ni,V,Fe,Cu,Mo和 B等却不同程度地降低了循环稳定性 ;添加 Si,Mo,V,Cr和 Al可明显改善合金电极的自放电性能 ;添加 Si,Cr,V可显著改善 AB2 合金电极的高温放电性能 .讨论了各种添加元素影响合金性能的可能原因.