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1.
研究钴离子部分取代铜离子对YBa2Cu3O6+δ的氧非计量值δ和氧渗透率的影响.对于钴替代的样品,氧非计量的绝对值变大,且其数值不再随温度和氧分压的变化发生显著变化.YBa2Cu2CoO6+δ样品在中、高温具有可观的氧渗透率.对于厚度为1.2 mm的致密YBa2Cu2CoO6+δ样品,在850℃时,只要在样品两端施加较小的氧分压差(PO2=21.2 kPa、 PO2=101 Pa),其氧渗透率即可达57 μmol/cm2 s, 明显高于YBa2Cu3O6+δ的氧渗透率(31 μmol/cm2 s).YBa2Cu2CoO6+δ的高氧渗透率在结构上可被归结为位于晶胞基面上的氧离子和氧空位的均匀分布.  相似文献   

2.
通过电化学途径和化学途径在YBa_2Cu_3O_7超导体表面制备了导电高分子聚吡咯膜,用以保护超导体不受环境作用的影响,实验结果发现电化学过程能破坏YBa_2Cu_O_7的超导性,而采用化学法制备的聚吡咯和聚氯乙烯混和材料包覆在YBa_2Cu_3O_7表面后,超导体不仅保持原有超导性,而且有很好的保护超导体免遭环境中酸和水作用的能力。  相似文献   

3.
La-Ba-Cu复合氧化物在催化消除NO反应中催化性能的研究   总被引:3,自引:0,他引:3  
合成了具有钙钛石结构的复合氧化物YBa2Cu3O7、LaBa2Cu3O7、LaBaCu2O5、La2BaCu3O7和La4BaCu5O12.考察了它们对NO分解和NO+CO反应的催化性能.结合化学分析、XRD、TPD和TPR对催化剂的表征结果,探讨了该系列复合氧化物对NO分解和NO+CO反应的催化机理.  相似文献   

4.
The performance of a carbon paste electrode (CPE) modified with SBA-15 nanostructured silica organofunctionalised with 2-benzothiazolethiol in the simultaneous determination of Pb(II), Cu(II) and Hg(II) ions in natural water and sugar cane spirit (cacha?a) is described. Pb(II), Cu(II) and Hg(II) were pre-concentrated on the surface of the modified electrode by complexing with 2-benzothiazolethiol and reduced at a negative potential (-0.80 V). Then the reduced products were oxidised by DPASV procedure. The fact that three stripping peaks appeared on the voltammograms at the potentials of -0.48 V (Pb2+), -0.03 V (Cu2+) and +0.36 V (Hg2+) in relation to the SCE, demonstrates the possibility of simultaneous determination of Pb2+, Cu2+ and Hg2+. The best results were obtained under the following optimised conditions: 100 mV pulse amplitude, 3 min accumulation time, 25 mV s(-1) scan rate in phosphate solution pH 3.0. Using such parameters, calibration graphs were linear in the concentration ranges of 3.00-70.0 x 10(-7) mol L(-1) (Pb2+), 8.00-100.0 x 10(-7) mol L(-1) (Cu2+) and 2.00-10.0 x 10(-6) mol L(-1) (Hg2+). Detection limits of 4.0 x 10(-8) mol L(-1) (Pb2+), 2.0 x 10(-7) mol L(-1) (Cu2+) and 4.0 x 10(-7) mol L(-1) (Hg2+) were obtained at the signal noise ratio (SNR) of 3. The results indicate that this electrode is sensitive and effective for simultaneous determination of Pb2+, Cu2+ and Hg2+ in the analysed samples.  相似文献   

5.
Hydrothermal reactions of a vanadate source, an appropriate Cu(II) source, bisterpy and an organodiphosphonate, H2O3P(CH2)nPO3H2(n= 1-5), in the presence of HF, yielded a family of materials of the type oxyfluorovanadium/copper-bisterpy/organodiphosphonate. Under similar reaction conditions, variations in diphosphonate tether length n provided the one-dimensional [{Cu2(bisterpy)}V2F2O2{HO3PCH2PO3}{O3PCH2PO3}](1) and [{Cu2(bisterpy)}V2F4O4{HO3P(CH2)2PO3H}](3), the two-dimensional [{Cu2(bisterpy)}V2F2O2(H2O)2{HO3P(CH2)2PO3}2] x 2H2O (2 x 2H2O), [{Cu2(bisterpy)(H2O2}V2F2O2{O3P(CH2)3PO3}{HO3P(CH2)3PO3H}(4) and [{Cu2(bisterpy)}V4F4O4(OH)(H2O){HO3P(CH2)5PO3}{O3P(CH2)5PO3}] x H2O (9 x H2O) and the three-dimensional [{Cu2(bisterpy)}3V8F6O17{HO3P(CH2)3PO3}4]0.8H2O (5 x 0.8H2O), [{Cu2(bisterpy)}V4F2O6{O3P(CH2)4PO3}2](8) and [{Cu2(bisterpy)(H2O)}2V8F4O8(OH)4{HO3P(CH2)5PO3H}2{O3P(CH2)5PO)}3] x 4.8H2O (10 x 4.8H2O). In addition, two members of the oxovanadium/Cu2(bisterpy)/organodiphosphonate family [{Cu2(bisterpy)}V2O4{HO3P(CH2)3PO3}2](6) and [{Cu2(bisterpy)}3V4O8(OH)2{O3P(CH2)3PO3}2{HO3P(CH2)3PO3}2] x 5H2O (7 x 5H2O) cocrystallized from the reaction mixture which provided 5. The overall architectures reveal embedded substructures based on V/P/O(F) clusters, chains, networks, and frameworks. In contrast to the oxovanadium/Cu2(bisterpy)/ organodiphosphonate family, several of the materials of this study also exhibit the direct condensation of vanadium polyhedra to produce binuclear and/or tetranuclear building units.  相似文献   

6.
李霞  许剑轶  王瑞芬  张胤 《应用化学》2011,28(12):1393-1396
通过高温固相法合成了LED用红色荧光粉Sr(1-1.5x)Mo0.8Si0.2O3.8∶Eu3+x(x=0.1,0.2,0.3,0.4,0.5)。 通过XRD、激发光谱和发射光谱测试了材料的物相组成以及发光性能。 x=0.1样品的XRD谱与JCPDS 08-0482(SrMoO4)的标准卡片相同。 Eu3+代替晶格中Sr2+的位置成为发光中心。 随着Eu3+含量x的增加,593 nm处的5D0-7F1跃迁和614 nm处的5D0-7F2跃迁发射强度会相互转换:当x≤0.4时,以磁偶极5D0-7F1跃迁为主,发射橙色光;而当x=0.5时,以电偶极5D0-7F2跃迁发射为主,发射红光。 可能是过量掺杂的Eu3+离子,只能存在于晶格空位形成缺陷,无法占据SrMoO4中Sr2+的格位中,Eu3+在晶格中占据非对称中心的格位,导致电偶极跃迁变成允许跃迁,从而增加了5D0-7F2跃迁,减弱了5D0-7F1跃迁。 因此,可以通过调节激活剂的含量获得不同发光色的荧光粉。 Eu3+掺杂的硅钼酸锶体系,614 nm激发下,在368 nm处出现宽的基质吸收峰和467 nm处7F0-5D2的跃迁峰,且这2处的吸收峰在x=0.5时比x=0.4时强3倍左右。 材料能非常好的吸收368 nm波长的光,产生颜色可调的橙红色。 与近紫外光LED芯片匹配良好。  相似文献   

7.
YBa2Cu3Ox(x=6-7)薄膜被合成在YSZ基底上,用FTIR,XPS,XRD等手段原位研究CO在薄膜上的吸附及加氢行为。CO吸附在Cu位置上,与YBCO体相中的O作用,生成表面CO2或-COO基团,导致YBCO中生产氧空位,使YBCO发生昌型转变,Cu^2+被还原为Cu^+或Cu^0.YBCO中的氧空位有利于CO、CO2及H2的吸附。CO、CO2在YBCO膜上的加氢产物为CH3OH、CH3  相似文献   

8.
The study of the pseudobinary system Cu(2)SnS(3-)Cu(2)SiS(3) shows that a solid solution (Cu(2)Si(x)Sn(1-x)S(3)) exists in the range 0.4 < or = Si/(Sn+Si) < or = 0.6. Based on diffuse reflectance and photoelectrochemical measurements these compounds show potential as absorber materials for photovoltaic devices. The compounds were prepared at 850 degrees C from copper sulfide, silicon, tin, and sulfur and were analyzed with single-crystal (for x approximately 0.40) and powder diffraction techniques. Optical band gaps of 1.25, 1.35, and 1.45 eV were observed for the three compositions x = 0.39, 0.48, and 0.61; cathodic photocurrent occurring is significant.  相似文献   

9.
The structure, anisotropic magnetic, electrical and thermal transport properties for single crystals of Ca(3)Co(4-x)Cu(x)O(9) (x = 0, 0.2, 0.4, 0.6 and 0.8) have been investigated systematically. The Cu-doping with x = 0.2 at Co-site is sufficient to drive the low-temperature spin-glass state in the Ca(3)Co(4)O(9) system. The value of resistivity along ab-plane decreases monotonously with increasing x in the whole temperature range studied, and around room temperature, the in-plane resistivity of Ca(3)Co(3.2)Cu(0.8)O(9) is about 71% smaller than that of the undoped sample. The temperature region where the Fermi-liquid transport mechanism dominates becomes remarkably narrowed due to the Cu-doping while the electronic correlation in the system is enhanced. With further addition of Cu in the Ca(3)Co(4)O(9) system, the in-plane thermopower (S(ab)) increases slowly and the room-temperature S(ab) for Ca(3)Co(3.2)Cu(0.8)O(9) is about 17% larger than that of the undoped sample. As a result, the power factor along the ab-plane is enhanced by about 3.8 times compared to the undoped sample. The results are suggested to originate from the variations of carrier concentration and electronic correlation in this system via the different Cu-doping states: Cu(3+)/Cu(2+) (Cu(3+) major) into the CoO(2) layer for x ≤ 0.4, while Cu(2+)/Cu(3+) (Cu(2+) major) into the Ca(2)CoO(3) layers for x > 0.4.  相似文献   

10.
在YBa~2Cu~3O~6~~~7超导催化剂上进行CO~2加氢制醇的反应,研究了温度、压力和空速对催化剂活性和甲醇收率的影响。对催化剂进行了XRD,原位FT-IR,XPS,ESR和AFM表征,表明YBa~2Cu~3O~6~~~7在反应状态下被还原分解,铜主要被还原为Cu^+;CO~2加氢制醇的中间态可能为醛基、甲氧基;反应前催化剂粒度较大,反应后催化剂变得松散,粒度变小。  相似文献   

11.
Ivaska A  Leppinen J 《Talanta》1986,33(10):801-806
A cathodic stripping method has been devised for determination of low concentrations of the flotation collectors ethyl xanthate, diethyl dixanthogen and diethyl dithiophosphate. The limit of detection for ethyl xanthate was 1 x 10(-8)M by the differential pulse technique and with deposition for 2 min at -0.1 V. Three peaks were observed, each increasing in different concentration ranges of ethyl xanthate. A reaction mechanism is proposed. The detection limit for diethyl dithiophosphate was 1 x 10(-7)M by the differential pulse technique and with deposition for 3 min at -0.1 V. The analytical method was applied to determine ethyl xanthate in a sulphide mineral flotation plant and the amount of adsorbed ethyl xanthate and diethyl dithiophosphate on Cu(2)S. It was found that the adsorbed ethyl xanthate forms nearly a monolayer on Cu(2)S and that the amount of adsorbed diethyl dithiophosphate corresponds approximately to 0.4 monolayer.  相似文献   

12.
The hydrothermal reaction of V2O5, Cu(CH3COO)2.H2O, 1,2-diaminopropane and [N(CH3)4]OH yields the novel three-dimensional open-framework solid [(Cu(1,2-pn)2)7-(V16O38(H2O))2].4H2O constructed from the new mixed-valence [V16O38(H2O)]7- clusters interconnected through mu 2-[Cu(1,2-pn)2]2+ groups.  相似文献   

13.
The core-level X-ray photoelectron emission spectra of the quasi-one dimensional spin 1/2 antiferromagnetic system Sr14-xCaxCu24O41(x=0, 3.5, 6, 7, 8.4) were measured. The main peak of Cu2p3/2 was about 933.8 eV, and the full width of half maximum height was about 3.3 eV. Simulation of Cu2p3/2 by XPSPEAK41 shows that the percents of Cu2+ and Cu3+ in Sr14Cu24O41 are 92.13% and 7.87%, no obvious change to Cu2p core-level is observed by the partial substituting Ca for Sr, and the average valence of Cu in this system is estimated to be 2.08. The main peak of O1s is about 531.0 eV, and the weak shoulder toward the low binding energy direction can be considered as the contribution of Ca-O bond. The binding energies of Ca2p3/2 and Sr3d5/2 indicate that their valence in this system are both +2, without mixed valence.  相似文献   

14.
The calculations of clusters modeling the fluorine-doping and oxygen deficiency of YBa2Cu3O2,have been performed by the method of all-electron ab initio Hartree-Fock with self-consistent crystal field Results show that in CuO planes electric charge significantly increases,the chemical valence of Cu decreases and the covalent bonding of Cu-O greatly weakens owing to oxygen deficiency,while the effect of F restores the local electronic structure of YBa2Cu3O7 The reported opinion that F occupied the oxygen vacancy in Cu-O chains seems disputable according to the calculated bonding characteristics.  相似文献   

15.
姜李  张波  孙剑  尹桂  尚通明  王玲  王睿勇 《无机化学学报》2010,26(10):1750-1755
本文介绍了一种紫外-可见和荧光双通道铜离子探针,该探针基于罗丹明-B,通过水合肼为桥梁来连接三苯胺,便利而廉价。其在水体系下对铜离子显示出了良好的选择性和极高的灵敏度(2.78×10-8mol·L-1)。并且,通过初步的活细胞测试,表明该铜离子探针有着良好的生物相容性和细胞穿透性,在生物、医药领域有着非常大的潜力。  相似文献   

16.
RESr2RuCu2O8(RE=Gd和Eu)的合成与物性研究   总被引:2,自引:0,他引:2  
报道了磁性超导体RESr2RuCu2O8(RE=Gd和Eu)单相样品的合成以及对其结构和物性的研究。结果表明,这类化合物的结构和YBa2Cu3O7-δ相类似;在这两类化合物中,超导电性与弱铁磁有序共存;两样品铁磁相变温度TM分别为136,130K,超导临界温度TC分别为46,35K;由于Gd^3 和Eu^3 离子磁矩的不同,两样品的磁性质存在一定的差别。  相似文献   

17.
以4-甲基-2,6-二甲酰基苯酚和1,3,3-三甲基-2-亚甲基吲哚啉为原料合成了能同时识别Cu2+和水合肼的螺吡喃双功能探针L,其结构经1 H NMR、13 C NMR、FT-IR和 H RMS进行了表征。通过紫外-可见光谱法、荧光光谱法、核磁共振和质谱研究了探针L在pH=7.40的Trus-HCl-乙醇溶液(1∶1, V/V)中与19种金属离子、18种阴离子及9种胺类化合物的识别特性。结果表明,在pH=7.40的Trus-HCl-乙醇溶液(1∶1, V/V)中,相对于其它干扰离子,L对Cu2+和水合肼具有特异选择性和专一性,制成试纸能够实现肉眼识别检测含μmol/L Cu2+的水样。尤为重要的是,制备的含L的TLC板能实现在紫外灯下对液体和气体水合肼的肉眼识别。将L应用于水样和药物中Cu2+或水合肼测定的回收率在83.5%~111.0%之间,相对标准偏差( RSD)<4%,说明L适用于环境污染监测和药物分析检测,具有潜在的应用前景。  相似文献   

18.
Cu2+ selective PVC membrane electrode based on new Schiff base 2, 2'-[1,9 nonanediyl bis (nitriloethylidyne)]-bis-(1-naphthol) as a selective carrier was constructed. The electrode exhibited a linear potential response within the activity range of 1.0 x 10(-6) - 5.0 x 10(-3) moll(-1) with a Nernstian slope of 29 +/- 1 mV decade(-1) of Cu2+ activity and a limit of detection 8.0 x 10(-7) mol l(-1). The response time of the electrode was fast, 10 s, and stable potentials were obtained within the pH range of 3.5- 6.5. The potentiometric selectivity coefficients were evaluated using two solution method and revealed no important interferences except for Ag+ ion. The proposed electrode was applied as an indicator electrode to potentiometric titration of Cu2+ ions and determination of Cu2+ content in real samples such as black tea leaves and multivitamin capsule.  相似文献   

19.
The crystal structures of three Al-rich compounds have been solved from X-ray single crystal diffractometry: τ(1)-MoPd(2-x)Al(8+x) (x = 0.067); τ(7)-Zr(Cu(1-x)Al(x))(12) (x = 0.514) and τ(9)-ZrCu(1-x)Al(4) (x = 0.144). τ(1)-MoPd(2-x)Al(8+x) adopts a unique structure type (space group Pbcm; lattice parameters a = 0.78153(2), b = 1.02643(3) and c = 0.86098(2) nm), which can be conceived as a superstructure of the Mo(Cu(x)Al(1-x))(6)Al(4) type. Whereas Mo-atoms occupy the 4d site, Pd(2) occupies the 4c site, Al and Pd(1) atoms randomly share the 4d position and the rest of the positions are fully occupied by Al. A B?rnighausen tree documents the crystallographic group-subgroup relation between the structure types of Mo(Cu(x)Al(1-x))(6)Al(4) and τ(1). τ(7)-Zr(Cu(1-x)Al(x))(12) (x = 0.514) has been confirmed to crystallize with the ThMn(12) type (space group I4/mmm; lattice parameters a = 0.85243(2) and c = 0.50862(3) nm). In total, 4 crystallographic sites were defined, out of which, Zr occupies site 2a, the 8f site is fully occupied by Cu, the 8i site is entirely occupied by Al, but the 8j site turned out to comprise a random mixture of Cu and Al atoms. The compound τ(9)-ZrCu(1-x)Al(4) (x = 0.144) crystallizes in a unique structure type (space group P4/nmm; lattice parameters a = 0.40275(3) and c = 1.17688(4) nm) which exhibits full atom order but a vacancy (14.4%) on the 2c site, shared with Cu atoms. τ(9)-ZrCu(1-x)Al(4) is a superstructure of Cu with an arrangement of three unit cells of Cu in the direction of the c-axis. A B?rnighausen tree documents this relationship. The ZrCu(1-x)Al(4) type (n = 3) is part of a series of structures which follow this building principle: Cu (n = 1), TiAl(3) (n = 2), τ(5)-TiNi(2-x)Al(5) (n = 4), HfGa(2) (n = 6) and Cu(3)Pd (n = 7). A partial isothermal section for the Al-rich part of the Mo-Pd-Al system at 860 °C has been established with two ternary compounds τ(1)-MoPd(2-x)Al(8+x) and τ(2) (unknown structure). The Vickers hardness (H(v)) for τ(1) was found to be 842 ± 40 MPa.  相似文献   

20.
研究了YBaCu3O6~7超导催化剂上CO2的加氢制醇反应。考察了温度、压力和空速等条件对催化剂反应性能的影响。反应的主要产物是甲醇、CO和少量甲醚。利用XPS、XRD和AFM等技术对催化剂的结构、铜的存在状态和反应活性位进行表征发现,在反应过程中,YBa2Cu3O6~7由orthombic相转变为tetragonal相。反应活性位可能是Cu(I)物种。反应后催化剂颗粒的分散程度明显提高  相似文献   

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