一个与准晶相关的新Al－Cu相

本文报道一个新Ａｌ－Ｃｕ相具有正交结构，空间群Ｆｄｄｄ．点阵常数为：ａ＝０．８１６６ｎｍ，ｂ＝０．９９９５ｎｍ，ｃ＝１．４１４９ｎｍ，表达式为Ａｌ４３．２Ｃｕ５６．８．该相与Ａｌ－Ｃｕ－Ｆｅ准晶的价电子浓度相同，是一个由ＣｓＣｌ结构衍生的类似相．     

BaClF：Eu^2＋的微波辐射合成

报道了用微波辐射法合ＢａＣｌＦ：Ｅｕ＾２＋荧光体，Ｘ－射线粉末衍射测定其相结构为四方晶系，晶胞参数为ａ＝０．４３８９３ｎｍ，ｃ＝０．７２２３ｎｍ测定了最大激发峰和最大发射峰；在２５４ｎｍ光激发下，测定了色坐标。     

Al—5Fe—2Ni合金析出相的Mossbauer谱

用Ｍｏｓｓｂａｕｅｒ谱学和ＸＲＤ方法研究了快速凝固Ａｌ－５Ｆｅ－２Ｎｉ（原子百分数）合金的析出相，结果表明，析出相为三元化合物Ａｌ９ＦｅｘＮｉ２－ｘ（０〈ｘ〈２）属于单斜晶系，晶格参数ａ＝０．８５８ｎｍ，ｂ＝０．６３１ｎｍ，ｃ＝０．６２１ｎｍ，β＝９４．８，它的Ｍｏｓｓｂａｕｅｒ谱为一套双线，同质异能移位ＩＳ＝０．１２ｍｍ．ｓ＾－１，四极分别ＱＳ＝０．３２ｍｍ．ｓ＾－１，线宽Г＝０．２６ｍｍ．ｓ＾     

快速凝固Al—Li—Cu—Mg—Zr合金中H相的Z相的TEM研究

用ＨＲＴＥＭ、ＴＥＭ及ＥＤＡＸ分析研究了Ａｌ－Ｌｉ－Ｃｕ－Ｚｒ合金中的一种新相（暂名Ｈ相）和六角Ｚ相的结构，确定Ｈ相具有四方点阵，点阵参数为ａ＝２．８ｎｍ，ｃ＝２．４ｎｍ，ＥＤＡＸ分析表明Ｈ明和Ｚ相均含有Ａｌ，Ｍｇ，Ｃｕ。发现Ｈ相与Ｚ相的共存取向关系为［１００］ｈ｜｜［１１２０］ｚ，［０１０］｜｜［０００１］Ｚ。还观察到Ｚ相中一种特有有的旋转畴结构。     

Fe73.5Cu1Mo3Si13.5B9微晶软磁合金的结构及其对磁性的影响

对Ｆｅ７３．５Ｃｕ１Ｍｏ３Ｓｉ１３．５Ｂ９微晶软磁合金的结构及其对合金磁性的影响了研究，结果表明，在最佳磁性能下，晶相点阵常数ａ＝０．２８４３ｎｍ，相当于Ｆｅ（Ｓｉ）固溶体中含Ｓｉ％（ｍｏｌ／ｍｏｌ）：１８－２０，体积百分数Ｖ＝７４．８％，晶粒尺寸Ｄ＝１４．６ｎｍ；残余非晶层厚度δ＝１．２３ｎｍ；当Ｔ退火≥５６０℃时明显有Ｆｅ－Ｂ化合物析出。Ｆｅ７３．５Ｃｕ１Ｍｏ３Ｓｉ１３．５Ｂ９合金的磁性不仅与     

快速凝固Al—Li─Cu—Mg—Zr合金中H相和Z相的TEM研究

用ＨＲＴＥＭ、ＴＥＭ及ＥＤＡＸ分析研究了Ａｌ─Ｌｉ—Ｃｕ—Ｍｇ—Ｚｒ合金中的一种新相（暂名Ｈ相）和六角Ｚ相的结构，确定Ｈ相具有四方点阵，点阵参数为α＝２．８ｎｍ，ｃ＝２．４ｎｍ，ＥＤＡＸ分析表明Ｈ相和Ｚ相均含Ａｌ、Ｍｇ、Ｃｕ发现Ｈ相与Ｚ相的共存取向关系为［１００］‖［１１２０］Ｚ，［１０１０］Ｈ‖［０００１］Ｚ。还观察到Ｚ相中一种特有的旋转畴结构     

一类Lazer—Mckenna吊桥型方程周期解的存在性

本文研究如下吊桥型方程的周期解问题ｕｔｔ＋ｕｘｘｘｘ＋εｕｉ＝ｆ（ｕ）＋ｈ（ｘ，ｌ）；ｕ（０，ｔ）＝ｕ（π，ｌ）＝ｕｘｘ（０，ｌ）＝ｕｘｘ（π，ｌ）＝０；ｕ（ｘ，ｌ＋２π）＝ｕ（ｘ，ｌ）。这个方程可以看成来自于Ａ．Ｃ．Ｌａｚｅｒ和Ｐ．Ｊ．Ｍｃｋｅｎｎａ在文［１］中提出的简单吊桥非线性振动模型ｕｔｔ＋ｕｘｘｘｘ＋δｕｉ＝－ｋｕ＾＋＋ｗ０＋εｈ（ｘ，ｌ）；ｕ（０，ｌ）＝ｕ（Ｌ，ｌ）＝ｕｘｘ（０，ｌ）＝     

Cf／Al—4.5Cu复合材料界面微结构的研究

利用挤压铸造法制造Ｃｆ／Ａｌ－４．５Ｃｕ复合材料，并在透射电子显微镜上了分析了基界面的微观结构特征。结果表明：Ｃｆ／Ａｌ－４．５Ｃｕ复合材料界面存在ＣｕＡｌ２与Ａｌ４Ｃ３析出相，Ａｌ４Ｃ３呈细棒状，而ＣｕＡｌ２相表现为柱状、块状片状；由于碳纤维与Ａｌ－４．５Ｃｕ基体间热膨胀系数不匹配产生的热应力铸造过程中Ａｌ－４．５Ｃｕ基体产生塑性有，使得在界面附近的基体和ＣｕＡｌ２相中产生大量位错缺陷。Ａｆ／Ａ     

THE ORDERING OF THE α-Fe(Si)PHASE IN Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9 ANNEALED ALLOY

用ＸＲＤ法研究了退火Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９合金中α－Ｆｅ（Ｓｉ）晶化相的有序化过程，结果表明，Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９非晶合金在４９０℃，１ｈ退火后，α－Ｆｅ（Ｓｉ）晶化相是具有ＤＯ３结构的有序相，有序畴为球形，直径为７．０ｎｍ，它随退炎温度的升颃是长大，在５９０℃退火后达１０．９ｎｍ，与α－Ｆｅ（Ｓｉ）的尺寸相当，此时α－Ｆｅ（Ｓｉ）的有序度为０．８，在８５０℃     

浇注温度对定向凝固Al－Cu合金热裂的影响EI

针对空心叶片类定向凝固铸件存在的热裂问题，开展了定向凝固热裂规律的研究。本文选择凝固参数较全的Ａｌ－Ｃｕ系合金，研究了定向凝固工艺参数之一的浇注温度对Ａｌ－０．６ｗｔ％Ｃｕ和Ａｌ－２．０ｗｔ％Ｃｕ合金热裂的影响。定向凝固热裂试验表明，提高浇注温度可以降低Ａｌ－０．６ｗｔ％Ｃｕ合金的热裂程度，但对Ａｌ－２．０ｗｔ％Ｃｕ则无作用。理论分析认为，合金在不可补缩区的冷却速率变化是改变合金热裂程度的重要因素。     

聚醚酮酮及其低聚物晶体的晶型结构

利用ＷＡＸＤ研究ＰＥＫＫ的晶型，得到两种晶型，其点阵常数为：Ⅰ型ａ＝０．７７５ ｂ＝０．６０９，ｃ＝１．０１及Ⅱ型ａ＝０．４１８，ｂ＝１．１３，ｃ＝１．００７；表明多晶型不仅与结晶条件也与分子结构有关。     

聚醚酮酮及其低聚物晶体的多晶型结构

利用WAXD研究PEKK的晶型，得到两种晶型其点阵常数（nm）为：I型a=0．775,b=0.609，c=101及II型a=0．418，b=1.13，c=1.007;表明多晶型不仅与结晶条件也与分子结构有关改变分子结构，在二氯乙烷中结晶都可将两种晶型完全分开对PEKK低聚物在二氯乙烷中结晶样品的研究证实了上述晶到     

Structure and properties of new perovskites La2MRhO6 (M = Mg, Zn)

New perovskite type oxides of Rh(IV) (La2MRhO6; M = Mg, Zn) have been prepared by conventional techniques used in solid state chemistry. Rietveld refinements from X-ray diffraction data confirm the space group P21/n for both compounds. This low symmetry is a result of two effects: (i) slight GdFeO3-type distorsion of the ideal perovskite structure due to the size of six-fold co-ordinated B cations and (ii) 1/1 ordering of the B-cations. The observed lattice parameters are a = 0.557 9(1) nm, b = 0.561 5(1) nm, c = 0.789 8(1) nm, = 90.01(6)° for La2MgRhO6 and a = 0.558 4(3) nm, b = 0.565 9(3) nm, c = 0.791 4(4) nm, = 90.0(2)° for La2ZnRhO6, respectively. The magnetic moment localized on Rh(IV) is strongly reduced compared to the spin-only value. The reasons for this phenomenon are discussed accounting for theoretical work on the magnetic behaviour of 2T2g-terms. However, a weak antiferromagnetic exchange interaction is observed. Both materials are intrinsic semiconductors.     

Martensitic Transformation in Magnetically Controlled Shape Memory Alloys Co50Ni20Ga30

The martensitic transformation for Co50Ni20Ga30 ribbon synthesized by the melt-spinning technique was studied by means of X-ray diffraction and ac magnetic susceptibility. The Co50Ni20Ga30 ribbon, having bcc phase with calculated lattice parameters of a=0.57431 nm at 313 K. It exhibits a structure transition from parent phase to martensite during cooling. The martensitic phase in Co50Ni20Ga30 ribbon is tetragonal structure with lattice parameters of a=b=0.5422 nm and c=0.6401 nm. (c/a>1). According to the changing of diffraction intensity for martensite and the change of ac magnetic susceptibility, the process of the martensitic transformation can be divided into three parts during cooling from 283 K to 213 K. When the temperature decreasing sequentially from 193 K to 110 K, the structure of the martensite has a change in which the a-axis decreases and c-axis increases. The morphologies of selfaccommodation were observeds. The parallelogram morphology, the diamond morphology and the fork morphology were     

Precipitations in an Yttrium-Containing Low-Expansion Superalloy

The resistance to stress-accelerated grain-boundary oxygen embrittlement and notch-bar rupture strength in Fe–Ni–Co–Nb–Ti low-expansion superalloy has been improved significantly by trace yttrium addition. The precipitates in the matrix as well as along the grain boundaries have been studied systematically. The platelet precipitates in the matrix and along the grain boundaries have a hexagonal crystal structure (space group, P6/mmm) with lattice parameters a = 0.498 nm and c = 0.408 nm. The crystallographic orientation relationship between the phase and the matrix is found to be . The semi-continuous discrete precipitates along the grain boundaries have an orthorhombic crystal structure with lattice parameters a = 0.45 nm, b = 0.80 nm and c = 1.20 nm. High-resolution images show that the interface between the precipitates and the matrix is semicoherent.     

A HRTEM and XRD Study of the Potassium Hexatitanate Nanowires

The structure of potassium hexatitanate (K_2Ti_6O_13) nanowires has been investigated using both the Rietveld powder diffraction profile fitting technique and high resolution transmission electron microscopy (HRTEM) image simulations. From the Rietveld analysis it was shown that the nanowires had a monoclinic structure of the space group C2/M and the lattice parameters were a=1.5582 nm, 6=0.382 nm, c=0.9112 nm. HRTEM conclusions agree with refinement results obtained from experimental XRD data. The good agreement between the experimental and simulated images confirms that the nanowires is indeed K2Ti6O13 nanowire.The growth axes of nanowires were mainly along the [010] direction.     

Structure of metastable precipitate in some Al–Cu–Mg–Ag alloys

Abstract

The high strength of some Al–Cu–Mg–Ag alloys has been attributed to very thin (~2·5 nm), but broad, hexagonal-shaped precipitates. Previous work has shown that the precipitates have a hexagonal unit cell, but different lattice parameters have been reported. In the present paper, the intensities of X-ray diffraction reflections from the precipitates have been measured on Buerger precession photographs, and it is shown that the crystal structure is monoclinic (space group P2/m) with the parameters a = b = 0·496 nm, c = 0·848 nm, γ = 120°. The special values of these parameters confer a hexagonal symmetry on the lattice. This unusual structure is a slightly distorted form of θ-CuAl₂, to which it appears to change after long aging times at 200°C.     

新型含氟8-羟基喹啉锌配合物的合成及光学性能研究

设计合成了3种新型含单氟8-羟基喹啉衍生物配体:(E)-2-[2-(2-氟代苯基)乙烯基]-8-羟基喹啉(4a)、(E)-2-[2-(3-氟代苯基)乙烯基]-8-羟基喹啉(4b)、(E)-2-[2-(4-氟代苯基)乙烯基]-8-羟基喹啉(4c)及其相应的锌配合物(5a)、(5b)、(5c),利用1 H-NMR、IR、MS、元素分析确认了其结构。测定了它们在DMF溶液中的荧光性质;荧光光谱显示化合物4a、4b、4c在DMF溶液中的λmax分别是505nm、487nm、513nm;5a、5b、5c的λmax分别是559nm、598nm、588nm,荧光光谱显示氟基位置的改变可以调控8-羟基喹啉锌配合物的发光性质。     

Morphologies and luminescence properties of SrZnO2 microstructure

The SrZnO2 of beardlike and sheetlike nanobundles, rod and treelike nanostructures have been synthesized by a citrate-gel combusting synthesis approach. As-prepared SrZnO2 shows orthorhombic structure with Pnma space group and unit cell with the lattice parameters: a = 5.830 A, b = 3.340 A and c = 11.348 A. By increasing the sintering temperature, the beardlike nanobundle gradually dissolved to form microrods and treelike microstructure. Citrate acid exerts a major influence in directing the formation of these unique SrZnO2 microstructures. These materials were analyzed for their use to luminescence materials. The as-made samples exhibit an efficient absorption and excitation band in the UV spectral region (centered at 380 nm). In the same time, the samples of with different morphologies showed a broad yellow emission peak centered at approximately 545 nm which should been associated with the composition and morphologies of sample or from the oxygen vacancies of semiconductor SrZnO2. The material may be used as novel conversion phosphors or host material of phosphor for white-light LEDs.