CaO-MnO_2混合矿化剂对硅微粉结合的SiC窑具析晶结构及性能影响的研究

在硅微粉结合的ＳｉＣ 窑具中添加ＣａＯ－ ＭｎＯ２ 混合矿化剂可充分发挥不同矿化剂的优点，而克服其不足之处，比添加单一矿化剂［１］［２］ 效果显著，采用ＸＲＤ 法测定混合矿化剂加入后析晶结构及含量，并以此为依据讨论窑具性能，得出ＣａＯ－ ＭｎＯ２ 混合矿化剂的最佳加入量为２－０％ 。

不同结合剂对熔融石英窑具性能与析晶结构的影响

主要对熔融石英结构、不同结合剂结合的窑具性能和高温析晶结构进行研究．通过不同结合剂含量的性能比较，确定最佳配方（高铝结合剂最佳含量为３０％，粘土结合剂最佳含量为２０％），高温烧成析晶结构（α－石英，α－方石英，莫来石）及其含量．

汝窑瓷釉呈色机理研究概述

汝窑是我国宋代五大名窑之一,汝窑青瓷素有“天青色”的美誉。从化学组成的角度看,汝釉中的主要着色元素是铁元素。汝釉具有低硅、高铝、高钙的特点,为汝瓷釉层中析晶—分相结构的形成提供了基本的理化条件。汝釉在较强的还原气氛下烧成,铁元素主要以二价铁离子的形式存在,使釉面呈较纯正的青色。汝釉的烧成温度较低,降温过程可能较慢,有利于釉层中析晶—分相结构的形成,而析晶—分相结构导致的物理着色作用有助于釉面表现出蓝色乳光。

Effect of concurrent precipitation on recrystallization textures in commercial Al-Mn alloys

The effect of concurrent precipitation on recrystallization textures in AA 3003 aluminum alloys was investigated using X-ray diffraction and electron backscattering diffraction（EBSD） analyses. A weak recrystallization texture was observed in the AA 3003 alloy annealed at 783 K due to the high annealing temperature. Under the same conditions, extremely high P {011 } （ 111 ） recrystallization textures were detected in the AA 3003 alloy added with 0. 39% Sc. Based on the EBSD results, no intensely preferential orientation nucleation of recrystallization grains was observed in the early stage of recrystallizafion for both alloys. However, concurrent precipitation strongly retarded the growth of recrystallization grains, except for P nucleation sites, thereby conferring an apparent initial growth advantage for P nucleation sites compared with other nucleation sites. Therefore, a sharp P {011 } 〈 111 〉 texture appeared in concurrently precipitated AA 3003 alloys.

Effect of minor Sc and Zr addition on microstructure and properties of ultra-high strength aluminum alloy

The Al-9Zn-2.8Mg-2.5Cu-xZr-ySc alloys （x=0, 0.15%, 0.15%; y=0, 0.05%, 0.15%）, produced by low-frequent electromagnetic casting technology, were subjected to homogenization treatment, hot extrusion, solution and aging treatment. The effects of minor Sc and Zr addition on microstructure, recrystallization and properties of alloys were studied by optical microscopy （OM）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The results show that Sc and Zr addition can refine grains of the as-cast alloy by precipitation of primary Al3（Sc,Zr） particles formed during solidification as heterogeneous nuclei. Secondary Al3（Sc,Zr） precipitates formed during homogenization treatment strongly pin the movement of dislocation and subgrain boundaries, which can effectively inhibit the alloys recrystallization. Compared with the alloy without Sc and Zr addition, the Al-Zn-Mg-Cu-Zr alloy with 0.05%Sc and 0.15%Zr shows the increase in tensile strength and yield strength by 172 MPa and 218 MPa, respectively. Strengthening comes from the contributions of precipitation, substructure and grain refining.

Isothermal annealing of cold-rolled Al-Mn-Fe-Si alloy with different microchemistry states

Microstructural evolution of a cold-rolled Al-Mn-Fe-Si alloy during annealing was studied. Except the as-cast variant, two other different homogenizations were considered, one gave a high density of fine dispersiods providing a considerable Zener drag influencing the softening behavior while the other gave a lower density of coarser dispersoid structure providing a much smaller drag effect. The gradual microstructural evolutions during annealing for the three variants were captured by interrupting annealing at different time. Effects of microchemistry state on recrystallization kinetics, recrystallized grain structure and texture were characterized by EBSD. It is demonstrated that the actual softening kinetics, final microstructure and texture are a result of delicate balance between processing condition and microchemistry state. Strong concurrent precipitation takes place in the case with high concentration of Mn in solid solution, which suppresses nucleation and retards recrystallization and finally leads to grain structure of coarse elongated grains dominated by a P texture component together with a ND-rotated cube component. On the contrary, when solute content of Mn is low and pre-existing dispersoids are relatively coarser, faster recrystallization kinetics is exhibited together with an equiaxed grain structure with mainly cube texture.

Synthesis and Crystal Structure of a New Imidazole Coordinated Octamolybdate Compound

The title compound (Himi)4[Mo8O26(imi)2]4H2O (imi = imidazole) 1 was synthe- sized by the reaction of H2MoO4 and imidazole in aqueous solution. Single-crystal X-ray analysis reveals that compound 1 is crystallized in the triclinic system, space group P with a = 10.6219(8), b = 10.7260(8), c = 11.3220(9) , a = 92.842(2), b =117.364(1), g = 101.655(1), C18H36Mo8N12- O30, Mr = 1668.11, V = 1106.8(2) 3, Z = 1, Dc = 2.503 g/cm3, F(000) = 804, m = 2.298 mm-1, the final R = 0.0714 and wR = 0.1651 for 3121 observed reflections with I > 2s(I). The X-ray crystal structure analysis suggests that compound 1 is built up by two imidazole ligands coordinated by the centrosymmetric octamolybdate anions, protonated imidazole cations and crystallization water molecules.

Experimental Study on Uniaxial Compressive Strength of Reservoir Ice

Uniaxial compression experiments on horizontal and ervoir were conducted at different temperatures and strain rates vertical samples of first-year freshwater ice in a res- with an electronic universal machine equipped with low temperature cabinet. The results show that there is no difference between the strengths of two horizontal samples with grain sizes ranging from 1 to 4 mm and 4 to 14 mm, while the strength of the 1--4 mm vertical samples is 1.4 times higher than that of the 4--14 mm vertical samples because of the change of crystal structure. For different load- ing directions, the strengths of the horizontal samples do not differ from those of the vertical samples with the same grain sizes. The relation among the uniaxial compressive strength, strain rate and temperature was established through data analysis in both the ductile and brittle regions.

Synthesis and Crystal Structure of Methyl(7,7-Dimethyl-2-amino-4-(4-chlorophenyl)-5-oxo-5,6,7,8-tetrahydro-4H-benzo-[b]-pyran-3-yl)Carboxylate

The title compound methyl (7,7-dimemyl-2-amino-4-(4-chlorophenyl)-5-oxo-5,6,7,8-tetrahydro-4H-benzo-[b]-pyran-3-yl) carboxylate (C19H20ClNO4, Mr = 361.81) was synthesized and crystallized. The crystal belongs to triclinic, space group P 1 with a = 8.519(2), b = 10.346(2), c = 11.481(3) A, α = 108.16(1), β = 107.78(2), γ= 91.83(2)°, Z = 2, V = 906.5(3) A3, Dc = 1.326 g/cm3, μ(MoKα) = 0.234 mm-1, F(000) = 380, R = 0.0467 and wR = 0.1270 for 3142 observed reflections (I > 2σ(I)). X-ray analysis reveals that the C(7), C(8), C(9), O(1), C(10) and C(11) atoms form a six-membered ring which adopts a boat conformation. In the ring, the distances of C(8)-C(9) and C(10)-C(11) are 1.332(3) and 1.357(3) A, respectively, which indicates that they are C=C double bonds. Another six-membered ring (C(8)-C(9)-C(15)-C(14)-C(13)-C(12)) adopts the half-chair confonnation. In addition, there are intermolecular hydrogen bonds in the crystal structure.

One-dimensional Zigzag Chain Coordination Polymer [Zn(μ-phth)(imi)_2]_∞ Bridged by ο-Phthalato

The reaction of zinc carbonate with o-phthalic acid and imidazole in an aqueous-alcohol solution led to the formation of colorless crystals of [Zn(-phth)(imi)2]∞. Single-crystal X-ray analysis has revealed that the complex crystallizes in a monoclinic system, space group Pn with a = 8.394(2), b = 9.976(3), c = 9.959(3) ? ?= 104.409(4)? V = 807.6(4) ?, Z = 2, C14H12N4O4Zn, Mr = 365.65, Dc = 1.504 g/cm3, ?= 1.544 mm-1, F(000) = 372, the final R = 0.0466 and wR = 0.1171 for 1834 reflections with I >2(I). The complex displays a zigzag infinite chain structure in which each zinc (Ⅱ) center is coordinated by two oxygen atoms and two nitrogen atoms to generate a ZnN2O2 distorted tetrahedral geometry. The neighboring zinc atoms are bridged by the o-phthalate ligand. Each chain is linked by hydrogen bonds with its neighbors to form a three-dimensional coordination polymer.

Perovskite Formation and Dielectric Responses in PZN Modified PMF-PZT Ceramics

PMF-PZN-PZT （0.01Pb（Mol/3Fe2/3）O3-xPb（Znl/3Nb2/3）O3-（O.99-x）P（Zro53Tio 47）03 piezoelectric ceramics）, where x = 0.00 0.01, 0.03, 0.05 and 0.07 were prepared by a conventional mixed-oxide method. The results show that the pure peroveskit phase forms in these ceramics. X-ray diffraction analysis indicated that the phase of the material is a MPB （morphotropic phase boundary） structure. The effects of PZN content on the crystal structure and electrical properties were investigated, optimal dielectric properties were achieved at composition x = 0.07 ceramics by calcination at 800 ℃ and sintering at 1,180 ℃, with a curie temperature of approximately 430 ℃. These results clearly show the significance of PZN in controlling the electrical responses of the PMF-PZN-PZT system.

X-ray Study on the Ring-substituted Phthalocyanines:Crystal Structure of Metal Free 1,4,8,11,15,18,22,25-Octa-butyloxyphthalocyanine

The crystal structure of 1,4,8,11,15,18,22,25-octa-butyloxyphthalocyanine was determined by X-ray diffraction methods. The crystal is of triclinic, space group P 1 with a = 14.0780(3), b = 14.3480(4), c = 17.0090(2) A, α = 72.156(2), β = 86.193(2), r= 73.655(2)°, C64H82N8O8, Mr = 1091.38, Z = 2, V = 3137.5(1) A3, Dc= 1.155 g/cm3, F(000) = 1172, μ(MoKα) = 0.077 mm-1, the final R = 0.0787 and wR = 0.2240 for 5795 observed reflections with I ≥ 2σ(I). The steric congestion between the neighboring butyloxy groups distorts the core of phthalocyanine into a saddle shape conformation. In the crystal lattice, molecules overlap to each other with π-π interaction but the extent of overlap is different along the three axial directions.

Growth and Characteristics of Nd^(3+):GdAl_3(BO_3)_4 Crystal

Nd3+:GdAl3(BO3)4 (NGAB) crystal with the size of 30 mm was grown from the solvent system of K2O-Gd2O3-MoO3-B2O3 by combining accelerated seed rotation technology with medium seeded solution growth (MSSG) method, and its crystal structure has been determined by X-ray powder diffraction. It crystallizes in the trigonal system, space group R32 with a = 9.2734(2), c = 7.2438(1) ? V = 538 ?, Z = 3 and Dc = 4.379 g/cm3. The absorption and emission spectra of NGAB in the function of s and polarizations at room temperature have been measured. UV generation tuneable in 378～382 nm, green (531 nm) generation and blue generation tuneable in 436～443 nm as well as red (669 nm) generation by self-frequency changing were obtained with the output of 105, 119.5, 445 and 19 mJ/pulse, respectively, when the crystal was pumped by a dye laser.

Synthesis and Study of Glutamine Acid Containing Citrates

Terms of synthesis were defined for the creation of new generation chelate fertilizers and for their experimental testing. Glutamine acid and citric acid containing chelate citrates of the general formulae M.gI.HL＇nHO were synthesized, where, M = Mn, Zn, Fe, Co, Cu; n = 0; 1; 1.5; gl-glutamine acid; HL-citric acid anion. Identity and composition of synthesized compounds were determined by microelemental analysis, melting temperature and X-ray diffraction analysis. X-ray diffraction analysis of the compounds and glutamine acid and citric acid （H4L） was used to determine their crystalline structure and roentgen-amorphous and iso-structural orders. Their solubility was studied in various solvents.

Structure and function of ALG-2,a penta-EF-hand calcium-dependent adaptor protein

ALG-2(a gene product of PDCD6) is a 22-kD protein containing five serially repetitive EF-hand structures and belongs to the penta-EF-hand(PEF) family,including the subunits of typical calpains.ALG-2 is the most conserved protein among the PEF family members and its homologs are widely found in eukaryotes.X-ray crystal structures of various PEF proteins including ALG-2 have common features:presence of eightα-helices and dimer formation via paired EF5s that are positioned in anti-parallel orientation.ALG-2 forms a homodimer and a heterodimer with its closest paralog peflin.Like calmodulin,a well-known four-EF-hand protein,ALG-2 interacts with various proteins in a Ca2+-dependent fashion,but the binding motifs are completely different.With some exceptions,ALG-2-interacting proteins commonly contain Pro-rich regions,and ALG-2 recognizes at least two distinct Pro-containing motifs:PPYP(X) nYP(X,variable;n=4 in ALIX and PLSCR3) and PXPGF(represented by Sec31A) .A shorter alternatively spliced isoform,lacking two residues and designated ALG-2 GF122,does not bind ALIX but maintains binding capacity to Sec31A.X-ray crystal structural analyses have revealed that binding of calcium ions induces the configuration of the side chain of R125 so that it opens Pocket 1,which accepts PPYP,but Pocket 1 remains closed in the case of ALG-2 GF122.ALG-2 dimer has two ligand-binding sites,each in a monomer molecule,and appears to function as a Ca2+-dependent adaptor protein to either stabilize a preformed complex or to bridge two proteins on scaffolds in systems of the endosomal sorting complex required for transport(ESCRT) and ER-to-Golgi transport.

Porous zinc(Ⅱ)-organic framework with potential open metal sites:Synthesis,structure and property

Reaction of Zn(NO3)2.6H2O with 5-(isonicotinamido) isophthalic acid(H2INAIP) in N,N-dimethylformamide(DMF) affords a new three-dimensional(3D) coordination polymer {[Zn(INAIP)(DMF)].0.5DMF.4H2O}n(1).The X-ray crystallographic structural analysis reveals that complex 1 is a 3D porous framework containing a potential open metal site inside the pores.Topology analysis confirms that complex 1 is a two-fold interpenetrated(10,3)-b net with both metal ion and ligand acting as 3-connecting nodes.The thermal stability,variable temperature X-ray diffraction pattern and N2 adsorption property of the complex are investigated.

Structural basis of the ultrasensitive calcium indicator GCaMP6

GCaMP is one of the most widely used calcium indicators in neuronal imaging and calcium cell biology. The newly developed GCaMP6 shows superior brightness and ultrasensitivity to calcium concentration change. In this study, we determined crystal structures of CaZ＋-bound GCaMP6 monomer and dimer and presented detailed structural analyses in comparison with its par- ent version GCaMP5G. Our analyses reveal the structural basis for the outperformance of this newly developed Ca2＋ indicator. Three substitution mutations and the resulting changes of local structure and interaction explain the ultrasensitivity and in- creased fluorescence intensity common to all three versions of GCaMP6. Each particular substitution in the three GCaMP6 is also structurally consistent with their differential sensitivity and intensity, maximizing the potential of using GCaMP6 in solving diverse problems in neuronal research and calcium signaling. Our studies shall also be beneficial to further structure-guided optimization of GCaMP and facilitate the design of novel calcium indicators.

Reversible phase transition of the 1:1 complex between 18-crown-6 and n-propylammonium triiodide

Solid-state structure of the crystalline 1：1 complex [C3H10N（18-crown-6）]＋[I3] （1） between 18-crown-6 and n-propylammonium triiodide has been determined at 293 and 93 K, respectively, showing a change from monoclinic P21/m to monoclinic P21/a. Crystal structural analysis shows that in addition to van der Waals＇ forces, conventional N-H..-O hydrogen bonds are the key interactions. Measurements of unit cell parameters versus temperature show that the values of one of the three axes and the crystal volume change abruptly and remarkably at 220 K, indicating a first-order phase transition. The lack of the mirror plane in the low temperature structure is the most important differences between the two structural forms. Dif- ferential scanning calorimetry （DSC） measurement confirms that I undergoes a reversible phase transition at about 220 K with a thermal hysteresis of 3.5 K. The relatively large latent heat makes 1 a good candidate for phase change materials. The phase transition is accompanied by an anomaly of dielectric constant during heating and cooling process near the phase transition temperature.

Photophysical properties of heteroaromatic ring-fused(di)benzosiloles

Benzosiloles fused to heterocycles such as thiophene, benzothiophene, and benzofuran, and indole- and benzosilole-fused dibenzosiloles were prepared by palladium-catalyzed intramolecular coupling of the corresponding 2-（arylsilyl）aryl triflates in good to high yields. Molecular and crystal structures of 5,7-dihydro-5,5,7,7-tetrakis（1-methylethyl）bis[1]benzosilolo-[2,3-b：3＇, 2＇-d]thiophene, 6-methyl-12,12-diisopropyl-12H-indololo[3,2-b][1]silafluorene, and 5,5,11,11-tetraisopropyl-5,11H-benzosilolo[3,2-c]silafluorene were determined by X-ray diffraction analysis. The UV absorption spectra of the （di）benzosilole derivafives in cyclohexane red-shifted when compared to 1,1-diisopropyldibenzosilole, indicating that replacing a benzene ring of dibenzosilole by the heterocycles as well as fusion of indole and benzosilole moieties onto dibenzosilole narrowed the HOMO- LUMO gaps of the n-conjugation system. The thiophene-fused benzosiloles were faintly fluorescent in solution and in the solid state, whereas the dibenzosiloles exhibited luminescence with moderate and high quantum yields in cyclohexane and in microcrystals, respectively. In other words, aggregation-induced emission was observed for the dibenzosiloles. Notably, 5,5,11,1 1- tetraisopropyl-5,11H-benzosilolo[3,2-c]silafluorene in microcrystals exhibited violet fluorescence （λmax = 396 nm） with a quantum yield of 0.70. Density functional theory （DFT） calculations of the prepared （di）benzosiloles were also performed.