温度对电沉积氢氧化镍电化学性能的影响

在0.1mol/L的Ni(NO3)2溶液中,采用电化学沉积法制备出适用于锌镍微电池的氢氧化镍电极,研究了电沉积温度对Ni(OH)2电极的电化学循环伏安性能以及充放电性能的影响。测试结果表明,电沉积方法制备的Ni(OH)2电极适合于微电池的制作。30°C下电沉积制备的Ni(OH)2电极具有优异的电化学性能,其质子扩散系数为7.71×10-12cm2/s,放电比容量为1285μAh/cm2,利用率达91.4%。     

Honeycomb-like layered cobalt(II) phosphonate with [O2CCH(OH)PO3]3− as ligand: Hydrothermal synthesis,crystal structure,and magnetic properties

A new cobalt(II) phosphonate, [enH₂]_0.5[Co(pa)(H₂O)] · H₂O (1) (H₃pa = hydroxy-phosphono-acetic acid, HO₂CCH(OH)PO₃H₂; en = ethylenediamine), has been hydrothermally synthesized and structurally characterized. Compound 1 has a honeycomb-like layer structure which is composed of CoO₆ octahedra and μ₃-pa ligands with the protonated en and lattice water molecules stabilized between the layers. Magnetic studies indicate that 1 shows weak ferromagnetic behavior, spin-glass behavior, and metamagnetic behavior.     

Strain-induced crystallization kinetics of vinylidene chloride/vinyl chloride (VDC/VC) copolymers. Part II. Effect of temperature

The strain-induced crystallization (SIC) behavior of vinylidene chloride/vinyl chloride (VDC/VC) copolymer is reported as a function of the uniaxial extension ratio and the temperature of the rubbery amorphous specimen. The copolymer studied was an 88/12 wt/wt VDC/VC copolymer with a weight average molecular weight of 100,000 containing liquid additives that function as processing aids. It was found that SIC is initiated at an extension ratio of approximately 3.5, independent of the stress and stretching temperature. The growth rate of the crystalline phase increases sharply with extension ratio above 3.5. The crystalline phase growth rate at a given extension ratio also increases sharply with temperature between 15°C and 35°C. The implications of film temperature control during bubble expansion on the blown film process are discussed.     

Synthesis,characterizations, and crystal structure of a novel 2D metal phosphonate: Na2[Cd2(H2O)3(O3PCH(OH)CO2)2] · 2H2O

A novel cadmium phosphonate compound Na₂[Cd₂(H₂O)₃(O₃PCH(OH)CO₂)₂] · 2H₂O (1) has been synthesized by hydrothermal reaction at 120 °C and characterized by single-crystal X-ray diffraction as well as with infrared spectroscopy, elemental analysis and thermogravimetric analysis. The structure of compound 1 comprises CdO₆ octahedra and CdO₇ pentagonal bipyramid connected by [O₃PCH(OH)CO₂]³⁻ to form a 2D layered structure with a one-dimensional channel system and the charge-compensating Na⁺ cations being located between two adjacent layers.     

Synthesis and crystal structure of mer-nitroaquatriamminenitrosylruthenium(II) nitrate [RuNO(NH3)3(NO2)(H2O)](NO3)2

The reaction between mer-[RuNO(NH₃)₃(NO₂)(OH)]Cl·0.5H₂O and an excess of 16 M HNO₃ leads to the protonation of the starting complex and crystallization of the complex with a coordinated water molecule and nitrite anion. The crystal structure of the product has been determined. The coordinated water molecule tends to be a weak acid with a measured pK_a of 2.4.     

三氧化二铁晶型对铁铬系高温变换催化剂性能的影响

以硝酸亚铁为原料,采用共沉淀法分别制备了α型、γ型和非晶体型3类晶型的Fe2O3高温变换催化剂,并对所制备催化剂的性能进行了对比评价.结果表明①Fe2O3的晶型对变换催化剂的性能有较大的影响.尽管γ-Fe2O3晶型催化剂比α-Fe2O3晶型催化剂具有更高的初始活性,但其结构的不稳定性造成催化剂强度低、密度大和耐热性能差的缺点;②非晶体型态Fe2O3极小的微观粒子尺寸和宏观上的非晶态物质"异向同性"特性,使得所制备催化剂具有较大的比表面积、相对低的密度、高强度、高耐热性和更高的活性稳定性等优点;③非晶体型态Fe2O3催化剂的综合性能最高,α-Fe2O3晶型的次之,而γ-Fe2O3晶型的综合性能最低.其中,非晶体型态Fe2O3催化剂在比γ-Fe2O3晶型催化剂强度提高30%的情况下,堆密度可降低15%左右,且其耐热后的活性(CO变换率)比γ-Fe2O3型催化剂提高6个百分点.     

Effects of additives on the electrodeposition of tin from an acidic Sn(II) bath

Additive effects of formaldehyde, propionaldehyde and benzaldehyde on the deposition of tin in acidic solution of tin(II) sulfate have been investigated. The effects of these additives on cathodic polarization and a.c. impedance was measured by galvanostatic or potentiostatic methods, respectively. The reduction products of the aldehyde during the deposition and the diffusion coefficient of Sn(II) in various solutions were also determined.     

Regulation of Y2O3 addition on structure and properties of Al2O3/ZrO2(Y2O3) directionally solidified eutectic ceramic

Al₂O₃/ZrO₂(Y₂O₃) directionally solidified eutectic ceramics (DSECs) with different Y₂O₃ addition were prepared. Three polymorphs of ZrO₂: m-ZrO₂, t-ZrO₂ and c-ZrO₂ appeared and disappeared in order with the increase of Y₂O₃ addition, the effects of Y₂O₃ addition amount on the mass fraction of ZrO₂ polymorphs were quantitatively analyzed. The gradual decrease of area fraction and average size of colony was attributed to the increase of constitutional undercooling region, the variation of interphase spacing in the colonies was explained via selection mechanism of dendrite tip. The maximum hardness and fracture toughness were 18.35 GPa and 8.55 MPa m^1/2 obtained at 9 mol% and 3 mol% Y₂O₃ addition, respectively. The hardness was determined by the mass fraction of m-ZrO₂ phase, the area fraction of intercolony and the residual compressive stress, and the toughening mechanisms were composed of microcrack toughening, t-m transformation toughening and residual stress toughening.     

Synthesis,crystal structure,photoluminescence of Ba3Y2(BO3)4:Er3+ and thermal expansion of Ba3Y2(BO3)4

The Ba₃Y_2–xEr_x(BO₃)₄ (х = 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) phosphors were obtained by crystallization from a melt. The Ba₃Y₂(BO₃)₄ crystal structure was refined from single crystal X-ray diffraction data to R = 0.037. Its anisotropic atomic displacement parameters for all atoms were refined for the first time. The borate crystallizes in the orthorhombic crystal system, space group Pnma with unit cell parameters a = 7.673(1), b = 16.44(1), c = 8.977(2) Å, V = 1132.3(3) ų, Z = 4. These phosphors are isotypical to those of the A₃M₂(BO₃)₄ (A = Ca, Sr, Ba, M = Ln, Y, Bi) family. The crystal structure contains the isolated BO₃ triangles, two general and a special one independent crystallographic sites for large cations, which are disordered over sites. Thermal behavior of Ba₃Y₂(BO₃)₄ was investigated by high-temperature X-ray powder diffraction and thermal expansion coefficients are calculated in a wide temperature range. An inflections of temperature dependencies of the unit cell parameters is observed in a range 600–740 °C. Luminescence spectra, excitation and kinetic curves of the Ba₃Y₂(BO₃)₄:Er³⁺ series are reported. A maximum luminescence intensity is observed for the x = 0.1 sample. According to vibrational spectroscopy data no structural changes upon activation of the Ba₃Y₂(BO₃)₄ matrix with the Er ions are observed.     

Effects of Eu content on the luminescent properties of Y2O3:Eu3+ aerogels and Y(OH)3/Y2O3:Eu3+@SiO2 glassy aerogels

This article describes the morphological, structural, and luminescent properties of Y₂O₃:Eu³⁺ aerogels and Y(OH)₃/Y₂O₃:Eu³⁺@SiO₂ glassy aerogels synthesized by the sol-gel method with Eu concentrations from 2.5 mol% to 30 mol%. XRD measurements indicated that both the aerogels and glassy aerogels had a monoclinic phase, but the crystallinity in the glassy aerogels was lower due to the presence of SiO₂. SEM images reveal that a three-dimensional porous network was formed in the aerogels due to the interconnection of coalesced Y₂O₃:Eu³⁺ nanoparticles. The 3D porous network was also observed in the glassy aerogels, coated with a silica shell. In both the aerogels and glassy aerogels, the size of the agglomerates decreased as the europium concentration increased. This, in turn, increased the average size of the macropores that formed their 3D network. Furthermore, the luminescent properties of the aerogels and glassy aerogels were studied under UV excitation, and it was observed that their red emission intensity increased continuously as the Eu³⁺ concentration increased. The luminescence of the aerogels was on average 50% higher than that of the glassy aerogels. Hence, our results indicate that porous and luminescent aerogels with and without silica are adequate for applications in sensing and catalysis.     

Hydrothermal synthesis,crystal structure and photoluminescent property of a novel 3-D [La2(C2O4)2(NO3)(OH)(H2O)] · 3H2O

A novel 3D [La₂(C₂O₄)₂(NO₃) (OH)(H₂O)] · 3H₂O 1 has been synthesized under hydrothermal conditions and characterized by elemental analyses, IR, TGA, X-ray powder diffraction, X-ray single crystal diffraction and photoluminescence. The bridging modes of both nitrates and oxalates in compound 1 are uncommon. We have unexpectedly generated an unusual compound by using the simplest ligands, oxalates and nitrates in the presence of nicotinate (HIN).     

阴离子对Mg(OH)2晶体生长及形貌的影响机理

以轻烧粉、氯化铵、硝酸铵、乙酸铵、硫酸铵为原料,氨气为沉淀剂,采用氨循环法制备氢氧化镁晶体,并通过扫描电镜（SEM）、X射线衍射（XRD）对其进行表征分析。采用Materials Studio分子模拟软件中的CASTEP模块,计算了Cl^-、NO₃^-、CH₃COO^-对氢氧化镁晶体（001）、（101）晶面生长的影响。结果表明,采用不同的镁盐得到不同形貌的氢氧化镁晶体阴离子电负性越大,对晶体形貌影响越小;Mg（OH）₂晶体的（001）、（101）晶面能量与布居数分析表明,Cl^-、NO₃^-、CH₃COO^-使晶体的（001）、（101）面的表面能增大、Fermi能级减小,阴离子与（001）、（101）晶面之间形成新的具有微弱共价性的离子键,影响晶体晶面的生长。理论计算较好地解释了不同形貌的氢氧化镁晶体的形成原因。     

Dynamic mechanical properties and morphology of styrene-divinylbenzene copolymer/poly(vinyl chloride) systems. (II). Effect of polymerization temperature

Effect of polymerization temperature on the phase-separated structure of the composite materials [P(St-DVB)/PVC systems] prepared by copolymerization of styrene (St) and divinylbenzene (DVB) in the presence of fine poly(vinyl chloride) (PVC) powder was studied by electron microscopy and dynamic mechanical test. P(St-DVB)/PVC systems have the two-phase nature with a styrene-divinylbenzene copolymer as the continuous phase [P(St-DVB) phase) and a PSt/PVC composite as the dispersed phase (PSt-PVC phase), in which PSt penetrates into the PVC domain. The crosslinking density of the P(St-DVB) phase is larger than that estimated from the recipe in the feed, suggesting that there exists a difference of the diffusion constants of styrene and divinylbenzene into the PVC particles on the paste formation and the polymerization process. The changes of the phase-separated structure of P(St-DVB)/PVC systems polymerized at various temperatures are also explained on the basis of the difference between the diffusion behavior of styrene and that of divinylbenzene into fine PVC particles at these temperatures.     

Co掺杂对（CeO2）0.92（Y2O3）0.06（La2O3）0.02电解质材料性能的影响

采用固相合成法合成CeO2基粉料(1-x)(CeO2)0.92(Y2O3)0.06(La2O3)0.02+xCoO1.5(x=0,0.5 mol%,1mol%和2mol%),并在不同温度下烧成。采用X射线衍射(X-ray diffraction,XRD)、Archimedes法、交流阻抗谱和热膨胀仪分别测试电解质材料的晶体结构、体积密度、离子电导率和热膨胀。结果表明:掺杂Co的试样经1500℃烧成后均为单一的立方萤石结构相,Co可以有效提高试样的烧结性能,降低烧结温度100℃;试样的晶界电导随着Co含量的增加而提高,当Co掺杂量为2mol%时,试样在700℃时表现出最高的离子电导率0.051s.cm-1。同时发现Co的掺杂对试样的热膨胀影响不大。     

Thermal prehistory,structure and high-temperature thermodynamic properties of Y2O3-CeO2 and Y2O3-ZrO2-CeO2 solid solutions

Ceria-based solid solutions are important materials for high- and medium-temperature electrochemical applications. However, the stabilities of both binary and ternary ceria-based solid solutions are insufficient at elevated temperatures, which limits their application as solid electrolytes or SOFC cathodes. Data on the high-temperature stability of ceria-based ceramics are unavailable in the literature. In the present study, we report a thermodynamic stability investigation of Y₂O₃-CeO₂ and Y₂O₃-ZrO₂-CeO₂ solid solutions. The thermal prehistories of binary and ternary systems were investigated using STA, XRD, and ESCA techniques. The vaporization processes were investigated in the temperature range of 1577–2227°С via the Knudsen effusion mass spectrometry technique. Using data on the component activity in solid-phase thermodynamic properties of Y₂O₃-CeO₂ solid solutions, which is represented as the Gibbs energy, the excess Gibbs energy was calculated as a function of the ceria mol. %. It was shown that the reduction of Ce⁴⁺ to Ce³⁺ in Y₂O₃-CeO₂ and Y₂O₃-ZrO₂-CeO₂ solid solutions corresponds to less-negative Gibbs energy compared to ZrO₂-CeO₂ solid solutions.     

高压烧结AlN（Y2O3）陶瓷的物相组成分析及热导率

用国产六面顶压机在5.0GPa,1300℃～1800℃条件下实现了以Y2O3为烧结助剂的AlN陶瓷体的高压烧结.用XRD对AlN高压烧结体的相组成进行了表征.研究表明:高压制备陶瓷体材料能够有效降低烧结温度和缩短烧结时间,可比传统烧结方法降低400℃以上.Y2O3是AlN有效的低温烧结助剂,在1300℃、1400℃烧结的AlN陶瓷体材料第二相物质以YAlO3和 Y4Al2O9为主.当烧结温度高于1600℃,AlN陶瓷的第二相物质主要以Y3Al5O12为主.烧结条件为5.0GPa/1700℃/75min,样品的热导率可达135W/(m·K).     

Synthesis and growth of nanotubes Mg3Si2O5(OH,F)4 composition under hydrothermal conditions

Nanotubes of magnesium hydrosilicate Mg₃Si₂O₅ (OH, F)₄ having the structure of chrysotile and increased thermostability in comparison with hydroxyl-chrysotile were synthesized under hydrothermal conditions at temperatures of 300–450°C and pressure of 30–100 MPa from mixtures of oxides of magnesium and silicon with the use NaF and NaOH as mineralizers. The conditions of the synthesis of the chrysotile nanotubes with varying content of fluorine (0.4–4.0 wt %) in the composition of chrysotile were determinated. The effect of the physical-chemical parameters of the synthesis on the growth of the OH-F-chrysotile tubes was tracked. The core role of concentration of F-containing mineralizer was shown.     

Effect of deposition temperature on phase composition,morphology and mechanical properties of plasma-sprayed Yb2Si2O7 coating

Phase composition, microstructure and mechanical properties of ytterbium disilicate (Yb₂Si₂O₇, YbDS) coatings fabricated via atmospheric plasma spray (APS) at different deposition temperatures were studied. Two layers with distinct pore distributions were observed in the YbDS top coat, the formation of pores correlated fairly well with the thermal gradients of splats after the droplets impinged on the substrate or deposited splats. Microstructure evolution with the thicknesses of YbDS top coat resulted from splat stacking and temperature accumulation. In addition, the significant crystallinity improvement and cracks reduction of YbDS top coat arose with the increased deposition temperature. X-ray diffraction patterns indicated that the metastable ytterbium monosilicate (Yb₂SiO₅, YbMS) appeared in YbDS coatings and they disappeared after thermal-treatment due to the phase transformation. The mechanical properties of the YbDS coatings were affected notably by the phase composition and microstructure.