低温超晶格YSZ/STO/YSZ电解质薄膜的制备及表征

采用脉冲激光沉积法(PLD),在Al2O3 (ALO)衬底上,将Y2O3∶ZrO2(YSZ)和SrTiO3 (STO)按照YSZ/STO/YSZ的顺序依次沉积,形成超晶格YSZ/STO/YSZ电解质薄膜,利用SEM、XRD和交流阻抗对其形貌、相结构和电学性能进行了表征.结果表明,衬底温度为700℃形成的超晶格YSZ/STO/YSZ电解质薄膜颗粒大且均匀,排列紧密且呈规律圆柱状;YSZ、STO均沿(111)方向择优生长;低温时电导率比单层YSZ电解质薄膜高出4个数量级,是较为理想的低温固体燃料电池电解质.     

Ce0.8Sm0.2O1.9-BaCe0.8Sm0.2O2.9复合电解质的成分对其电化学性能的影响

采用一步溶胶凝胶法制备摩尔比分别为9∶1、7∶3、5∶5和3∶7的复合电解质Ce0.8Sm0.2O1.9(SDC)-BaCe0.8Sm0.2O2.9(BCS)粉末,研究复合电解质SDC-BCS的相成分对电导率及其电化学性能的影响.结果表明:随着SDC含量的增加,复合电解质SDC-BCS的晶粒尺寸增大、电导率提高;复合电解质的晶界电导率均高于单相SDC的晶界电导率.不同成分的复合电解质制备的NiO-SDC-BCS|SDC-BCS|LSCF-SDC-BCS单电池的功率密度随着SDC含量的增加而提高.当SDC∶BCS的摩尔比为9∶1时,其单电池700 ℃的最大功率密度为550 mW/cm2,是单电池NiO-SDC|SDC|LSCF-SDC最大功率密度的3倍.     

原料NiO粉末对燃料电池Ni/SDC阳极材料微结构和性能的影响

分别采用商用氧化镍和煅烧碱式碳酸镍所得氧化镍粉末与Ceo.8Smo.2O2-δ(SDC)粉末混合,经压制烧结制得燃料电池NiO/SDC阳极烧结体,经H2还原后得到Ni/SDC金属陶瓷阳极材料,考察了不同NiO原料和加入量对阳极烧结体和阳极材料的微结构及相关性能的影响,还对以Ni/SDC为阳极构建的燃料电池单电池的性能进行了测试.实验结果表明:煅烧碱式碳酸镍所得NiO粉末和商用NiO粉末的平均粒径分别约为1.1 μm和8μm,前者更为均匀细小;由煅烧碱式碳酸镍所得NiO所制备的Ni/SDC阳极材料具有更高的电导率,含40; NiO的阳极材料(S-Ni/40SDC),在H2气氛中的电导率可达117.5 S·cm-1.以煅烧碱式碳酸镍所得的NiO制备的NiO/SDC为阳极,SDC为电解质,(Y0.5Ca0.5) BaCo3ZnO7-50SDC为阴极的单电池在700℃下的最大输出功率达225 mW/cm2,开路电压为0.85 V,电池性能优于以商用NiO为阳极原料所构建的单电池.     

反应磁控溅射制备AZO薄膜相结构的演化及机理研究

在室温下,利用直流反应磁控溅射技术在不同的氧气流量下沉积ZnO∶ Al (AZO)薄膜.采用XRD、SEM和TEM技术分析薄膜相成分、表面截面形貌及微观结构.结果表明:氧气流量为2.5 sccm时,沉积形成的薄膜为不透明具有金属导电性能的AZO/Zn( AZO)双层复合膜结构;氧气流量为3.5 sccm时,沉积形成了透明导电的AZO薄膜;氧气流量为5.0 sccm时,形成了透明不导电且含有纳米Al2O3颗粒的AZO薄膜;此外,AZO薄膜在400℃退火后,薄膜晶粒长大和(002)晶面方向择优生长更加明显以及高氧气流量沉积的AZO薄膜中的纳米Al2O3颗粒消失.     

固体氧化物燃料电池电解质8YSZ薄膜的水系流延

本文采用水系浆料流延成型法制备固体氧化物燃料电池SOFC的电解质材料(8;摩尔分数Y2O3,稳定的ZrO2,下称8YSZ)薄膜,研究了三种不同类型的分散剂对8YSZ浆料稳定性的影响.通过优化pH值和分散剂用量等因素,使浆料的稳定性达到最佳,获得固相含量高达62;质量分数的适合流延的8YSZ水系浆料.以该浆料为原料,采用流延的方法成型8YSZ薄膜,获得了显微结构均匀、相对密度达49.4;、表面光滑、无裂纹、柔韧性好、干燥后厚度为50 μm左右的薄膜素坯.该素坯在1350℃保温4 h烧结得到相对密度大于96;的致密8YSZ烧结薄膜.     

柠檬酸法制备固体氧化物燃料电池阳极材料Ni/SDC

采用硝酸盐-柠檬酸法合成出不同NiO含量的NiO/Ce_(0.8)Sm_(0.2)O_(1.9)(NiO/SDC)复合粉体,借助差热热重、XRD等对粉体的形成条件和相组成等进行了分析,并对粉体的比表面、粒度等进行了测定.由NiO/SDC粉体制备出固体氧化物燃料电池Ni/SDC金属陶瓷阳极材料,并对其微结构及相关性能进行了测试分析.结果表明:硝酸盐-柠檬酸法可以在较低的温度下合成出高比表面积的NiO/SDC粉体.制备的Ni/SDC阳极材料具有均匀细小的晶粒度和孔隙,以及高的电导率.1350 ℃烧结含55;NiO的NiO/SDC烧结体还原后所得Ni/SDC试样的孔隙率和电导率(700 ℃,H_2中)分别为38;和1825 S·m~(-1).     

衬底温度对Cu2O薄膜结构和性能的影响

采用射频磁控溅射技术在石英衬底上制备了Cu2O薄膜。系统研究了衬底温度对薄膜结构、光学和电学性能的影响。XRD的结果显示,在所有衬底温度条件下均可得到单相的Cu2O结构,而且随着衬底温度由500 K升至800 K,薄膜表现出(111)择优取向的生长特点。电学和光学测试结果表明,室温电导率和光学带隙随着衬底温度的升高而增加,800 K制备的薄膜的带隙值最高约为2.58 eV。     

不同应力下的双层钙钛矿锰氧化物La1.3Sr1.7Mn2O7薄膜输运特性研究

采用脉冲激光沉积(PLD)法分别在SrTiO3(100)、LaAlO3 (100)和MgO(100)单晶基片上制备了双层钙钛矿锰氧化物La13Sr17Mn2O7(LSMO)薄膜.X射线衍射谱表明三个样品均沿衬底的晶向择优生长;原子力显微镜显示薄膜表面均光滑致密.采用标准四探针法对薄膜的阻温特性进行了研究,发现SrTiO3 (100)和LaAlO3(100)基片上生长的薄膜呈现出明显的金属-绝缘体转变,转变温度分别为340 K和330 K.而在MgO基片上显示绝缘体态,无金属-绝缘体转变.结合阻温曲线的拟合及薄膜与衬底的晶格失配计算,从薄膜应力和激活能变化的角度分析了样品出现不同阻温特性的内在机制.     

多晶氮化铜薄膜制备及性能研究

采用反应射频磁控溅射的方法在不同的氮气分压的条件下,在玻璃基底上成功制备了氮化铜(Cu3N)薄膜.XRD显示氮气的气氛影响薄膜的择优生长取向,在低氮气气氛时薄膜择优[111]晶向生长,在高的氮气气氛条件下薄膜的择优生长取向为[100].用Scherrer公式估算出薄膜晶粒的大小在17～26nm之间,实验并研究了薄膜的热稳定性和电学性质.结果表明,薄膜的热稳定性较差,在200℃退火1h后已经完全呈Cu的相,薄膜的电阻率随着填隙原子的数目减少从导体到绝缘体发生不连续的改变.     

表面预处理对SiO2/Si结构上APCVD生长SiC薄膜的影响

采用S iH4-C3H8-H2气体反应体系在S iO2/S i复合衬底上进行了S iC薄膜的APCVD生长。实验结果表明,H2表面预处理温度过高或时间过长会导致衬底表面S iO2层熔化再结晶或被腐蚀掉。通过“先硅化再碳化”的工艺方法可以较好地解决S iO2/S i复合衬底上S iC成核困难以及粘附性差的问题,同时还可以有效抑制S iO2中的O原子向S iC生长膜扩散。选择预处理温度和薄膜生长温度为1180℃、H2预处理、S iH4硅化和C3H8碳化时间均为30 s的最佳生长条件时,可以得到<111>晶向择优生长的多晶3C-S iC外延薄膜,薄膜生长速率约为2.0~2.5nm/m in.     

Triethyl ammonium salt of O,O′-bis(p-tolyl)dithiophosphate, [Et3NH]+[(4-MeC6H4O)2PS2]−

Triethyl ammonium Salt of O,O′-bis(p-tolyl)dithiophosphate and O,O′-bis(m-tolyl)dithiophosphate have been obtained by reaction of p- and m-cresol, respectively with P₂S₅ in toluene and have been characterized by elemental analysis, IR, ¹H and ³¹P NMR spectroscopy. The molecular structure of O,O′-bis(p-tolyl)dithiophosphate has been determined. Crystal data: [Et₃NH]⁺[(4-MeC₆H₄O)₂PS₂]⁻: Monoclinic, P2₁/c, a=15.2441(9) ?, b=10.415(2) ?, c=3.9726(9) ?, β=91.709(7)°, V=2217.5(1) ?⁻³, Z=4.Supplementary materials Additional material available from the Cambridge Crystallographic Data Centre (CCDC no. 600927 for [Et₃NH]⁺[(4-MeC₆H₄O)₂PS₂]⁻ comprises the final atomic coordinates for all atoms, thermal parameters, and a complete listing of bond distances and angles. Copies of this information may be obtained free of charge on application to The Director, 12 Union Road, Cambridge CB2 2EZ, UK (fax: +44-1223-336033; email: deposit@ccdc.cam.ac.uk or www:http://www.ccdc.cam.ac.uk).     

First-principles coexistence simulations of supercooled liquid silicon

We perform first-principles coexistence simulations of the low-density and the high-density phases of supercooled liquid silicon and find a negative slope for the coexisting line in the temperature-pressure plane. Electron density maps and electron-localization function plots of the two phases of silicon show marked differences. The calculated differences suggest more localized electrons in the low-density liquid compared to the high-density liquid, coming from an increased population of covalent bonds, which further explain the calculated negative slope in the two phase coexistence regime. This is consistent with the presence of a pseudo-gap in low-density liquid silicon, absent in the high-density liquid which shows a metallic behavior.     

Crystal structures of thecis andtrans isomers of dithiahexahydro[3.3]metacyclophane

Structures of both thecis andtrans isomers of dithiahexahydro[3.3]metacyclophane, ?C₆H₄?CH₂SCH₂?C₆H₁₀?CH₂SCH₂?, have been determined, wherecis andtrans refer to the attachments to the cyclohexane ring. Thecis form crystallizes in the monoclinic space groupP2₁/c witha=8.4299(11)Å,b=21.772(2)Å,c=8.9724(13)Å, β=116.574(11)^o, andZ=4. Thetrans isomer packs into the monoclinic space groupP2₁ witha=8.159(16)Å,b=10.185(5)Å,c=9.558(2)Å, β=112.435(18)^o, andZ=2. The cyclohexane ring of thecis isomer is in the chair conformation, while the cyclohexane of thetrans isomer is found in a twisted boat conformation.     

CTAB与SDBS对碳酸锶粒子生长形态调控及机理研究

以表面活性剂CTAB和SDBS为化学添加剂,采用化学共沉淀法对碳酸锶晶体的生长形态进行调控,成功地制备出了实心的树枝状和花瓣为空心的花状碳酸锶粉体,并用X射线衍射(XRD)、扫描电子显微镜(SEM)和傅里叶变换红外光谱(FT-IR)等分析手段对样品进行了表征;最后重点对化学添加剂可能产生的影响机理进行了初步的探讨.结果表明,CTAB和SDBS在晶体生长的过程中能起到显著的影响作用,两者对粒子分散性能的作用效果相反,而且后者对晶体(013)和(213)晶面表面能降低的贡献明显大于前者.     

Crystal structures of the cis and trans isomers of a tetrathia[3.3.3.3]cyclophane

Both the cis and trans isomers of 3,11,18,26-tetrathiatricyclo[26.2.2.1^5,9.2^13,16.1^20,24] hexatriaconta-5,7,9,20,22,24-hexene have been prepared and structurally characterized. Each of these centrosymmetric tetrathia dimers includes two cyclohexane rings in chair conformations with either 1,4-cis or 1,4-trans bonding and two meta-substituted benzene rings. The cis isomer packs into the monoclinic space group P2₁/a with a = 10.485(3)Å, b = 10.3956(18)Å, c = 14.1343(10)Å, = 105.200(13)°, Z = 2 and refined to an R factor of 0.046. The trans isomer crystallizes in the monoclinic space group P2₁/c with a = 10.7217(12)Å, b = 5.6797(7)Å, c = 25.415(5)Å, = 96.001(12)°, Z = 2 and refined to an R factor of 0.043. In the cis structure each benzene ring faces a cyclohexane ring while in the trans structure the cyclohexane rings face one another.     

Crystal structure of Zn4Na(OH)6SO4Cl·6H2O

The structure of Zn₄Na(OH)₆SO₄Cl·6H₂O, a secondary mineral from Hettstedt, Germany, was determined by single-crystal X-ray diffraction. The crystals are hexagonal,a=8.413(8),c=13.095(24) Å, space group $P\bar 3$ , Z=2. The structure was refined to R=0.0554 and R_w=0.0903 for 970 reflections with I≥3σ(I). The structure can be described as zinc hydroxide layers perpendicular toc, from which sulfates and chlorides extend. The layers are held together by a system of hydrogen bonds involving hexaaquo Na⁺ ions which occupy the interlayer space.     

Synthesis and Crystal Structure of 5-[2-(6-bromonaphthalenyloxymethyl)]-3-(4-morpholinomethyl)-1,3,4-oxadiazole-2(3<Emphasis Type="Italic">H</Emphasis>)-thione

Abstract  The title compound, C₁₈H₁₈BrN₃O₃S, a derivative of 1,3,4-oxadiazole, crystallizes in the triclinic space group P-1 with unit cell parameters a = 6.8731(3), b = 8.9994(4), c = 15.7099(6) ?, α = 92.779(3)°, β = 130.575(3)°, γ = 107.868(4)°, Z = 2. The dihedral angle between the mean planes of the planar naphthyl and morpholine (chair) rings with the planar oxadiazol ring is 50.1(8) and 76.8(6)°, respectively. The planar naphthyl ring is twisted 52.2(5)° with the mean plane of the morpholine ring. A group of four intermolecular close contacts are observed between a bromine atom and hydrogen atoms from the closely packed naphthyl, morpholine and oxy–methyl groups in the unit cell. These molecular interactions in concert with an additional series of π–π stacking interactions that occur between the center of gravity of the two 6-membered rings of the naphthalene group influence the twist angles of each of these three groups. A MOPAC AM1 calculation of the conformation energy of the crystal structure [226.0128(9) kcal] compared to that of the minimum energy structure after geometry optimization [29.9744(1) kcal] reveals a significantly reduced value. The twist angles of the three groups above also change after the AM1 calculation giving support to the influence of both intermolecular C–H···Br short-range interactions and Cg π–π stacking interactions on these angles which therefore play a role in stabilizing crystal packing. Graphical Abstract  Crystal structure of 5-{[(6-bromonaphthalen-2-yl)oxy]methyl}-3-(morpholin-4-ylmethyl)-1,3,4-oxadiazole-2(3H)-thione, C₁₈H₁₈BrN₃O₃S, is reported and its geometric and packing parameters described and compared to a MOPAC computational calculation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

电沉积法制备ZnO纳米棒阵列及其发光特性

本文以掺F的SnO2导电玻璃为基板,以硝酸锌水溶液为电解液,采用三电极恒电位体系电沉积制备ZnO纳米棒阵列,系统考察了硝酸锌浓度和沉积电位等工艺参数对ZnO纳米棒阵列的微观形貌及其发光性能的影响规律.结果表明,硝酸锌浓度和沉积电位对纳米棒阵列的形貌有显著影响,控制适宜的工艺条件可以制备出直径分布均匀、结晶性好且纯度高的六方纤锌矿ZnO纳米棒阵列.荧光光谱分析表明,电沉积制备出的ZnO纳米棒阵列在385 nm附近有一个强荧光发射峰,且发光性能稳定、对纳米棒阵列微观形貌的细微变化不敏感,使其在发光二极管和激光器等领域具有广阔的应用前景.     

Crystal structure of irisolidone from the flowers of Pueraia lobata

Irisolidone (5,7-dihydroxy-6,4′-dimethoxyisoflavone) was isolated from the flowers of Pueraia lobata and its crystal structure was examined by X-ray single crystal diffraction. The crystal structure of irisolidone is monoclinic, space group P2₁/c with a = 15.491(9) ?, b = 7.895(4) ?, c = 13.321(7) ?, β = 110.546(9)° and Z = 4. Hydrogen bonding and aromatic π–π stacking assemble the title compound into a three-dimensional networking structure.