scholarly journals Using a Three-Dimensional Reduction Method in the High-Efficiency Grain Selector and Corresponding Grain Selection Mechanism

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1781
Author(s):  
Xintao Zhu ◽  
Fu Wang ◽  
Shuaipeng Zhang ◽  
Tobias Wittenzellner ◽  
Jessica Frieß ◽  
...  

In the development of a high-efficiency grain selector, the spiral selectors are widely used in Ni-based single crystal (SX) superalloys casting to produce single crystal turbine blades. For the complex three-dimensional structure of the spiral, a 2D grain selector was designed to investigate in this paper. As a result, the parameters of two-dimensional grain selection bond and the corresponding grain selection mechanism were established, and the three-dimensional grain selection bond was designed again by means of two-dimensional coupling optimization parameters.

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 780 ◽  
Author(s):  
Xintao Zhu ◽  
Fu Wang ◽  
Dexin Ma ◽  
Andreas Bührig-Polaczek

Single crystal (SX) is widely used in modern turbine blades to improve the creep fracture, fatigue, oxidation, and coating properties of the turbine, so that the turbine engine has excellent performance and durability. In this paper, the single crystal super alloy MM247LC is used as the research material. The evolution of grain structure in a two-dimensional grain selector was studied by directional experiments, and the mechanism of grain selection in the two-dimensional channel during directional solidification was clarified. In order to optimize the production process of single crystal turbine blades, the effects of the geometrical structure of a Z-type separator (i.e., wire diameter and take-off angle) on the crystal orientation, microstructure, and grain efficiency of blades were discussed.


2019 ◽  
Vol 75 (2) ◽  
pp. 196-199 ◽  
Author(s):  
Ning-Ning Chen ◽  
Jian-Ning Ni ◽  
Jun Wang ◽  
Jian-Qing Tao

A novel two-dimensional (2D) ZnII coordination framework, poly[[μ-1,3-bis(2-methyl-1H-imidazol-1-yl)benzene](μ-5-nitrobenzene-1,3-dicarboxylato)zinc(II)], [Zn(C8H3NO6)(C14H14N4)] n or [Zn(NO2-BDC)(1,3-BMIB)] n [1,3-BMIB is 1,3-bis(2-methyl-1H-imidazol-1-yl)benzene and NO2-H2BDC is 5-nitrobenzene-1,3-dicarboxylic acid], has been prepared and characterized by IR, elemental analysis, thermal analysis and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis revealed that the compound is a new 2D polymer with a 63 topology parallel to the (10\overline{2}) crystal planes based on left-handed helices, right-handed helical NO2-BDC–Zn chains and [Zn2(1,3-BMIB)2] n clusters. In the crystal, adjacent layers are further connected by C—H...O hydrogen bonds, C—H...π interactions, C—O...π interactions and N—O...π interactions to form a three-dimensional structure in the solid state. In addition, the compound exhibits strong fluorescence emissions in the solid state at room temperature.


Author(s):  
José L. Carrascosa ◽  
José M. Valpuesta ◽  
Hisao Fujisawa

The head to tail connector of bacteriophages plays a fundamental role in the assembly of viral heads and DNA packaging. In spite of the absence of sequence homology, the structure of connectors from different viruses (T4, Ø29, T3, P22, etc) share common morphological features, that are most clearly revealed in their three-dimensional structure. We have studied the three-dimensional reconstruction of the connector protein from phage T3 (gp 8) from tilted view of two dimensional crystals obtained from this protein after cloning and purification.DNA sequences including gene 8 from phage T3 were cloned, into Bam Hl-Eco Rl sites down stream of lambda promotor PL, in the expression vector pNT45 under the control of cI857. E R204 (pNT89) cells were incubated at 42°C for 2h, harvested and resuspended in 20 mM Tris HC1 (pH 7.4), 7mM 2 mercaptoethanol, ImM EDTA. The cells were lysed by freezing and thawing in the presence of lysozyme (lmg/ml) and ligthly sonicated. The low speed supernatant was precipitated by ammonium sulfate (60% saturated) and dissolved in the original buffer to be subjected to gel nitration through Sepharose 6B, followed by phosphocellulose colum (Pll) and DEAE cellulose colum (DE52). Purified gp8 appeared at 0.3M NaCl and formed crystals when its concentration increased above 1.5 mg/ml.


2019 ◽  
Author(s):  
Isaiah R. Speight ◽  
Igor Huskić ◽  
Mihails Arhangelskis ◽  
Hatem M. Titi ◽  
Robin Stein ◽  
...  

Solid-state mechanochemistry revealed a novel polymorph of the mercury(II) imidazolate framework, based on square-grid (sql) topology layers. Reaction monitoring and periodic density functional theory calculations show that the sql-structure is of higher stability than the previously reported three-dimensional structure, with the unexpected stabilization of a lower dimensionality structure explained by contributions of weak interactions, which include short C-H···Hg contacts.


2019 ◽  
Vol 30 ◽  
pp. 07014
Author(s):  
Mikhail A. Stepovich ◽  
Dmitry V. Turtin ◽  
Elena V. Seregina ◽  
Veronika V. Kalmanovich

Two-dimensional and three-dimensional mathematical models of diffusion and cathodoluminescence of excitons in single-crystal gallium nitride excited by a pulsating sharply focused electron beam in a homogeneous semiconductor material are compared. The correctness of these models has been carried out, estimates have been obtained to evaluate the effect of errors in the initial data on the distribution of the diffusing excitons and the cathodoluminescence intensity.


2009 ◽  
Vol 65 (3) ◽  
pp. m118-m120
Author(s):  
Olha Sereda ◽  
Helen Stoeckli-Evans

The title coordination polymer, [Cd3Co2(CN)12(C2H8N2)4]n, has an infinite two-dimensional network structure. The asymmetric unit is composed of two crystallographically independent CdIIatoms, one of which is located on a twofold rotation axis. There are two independent ethylenediamine (en) ligands, one of which bis-chelates to the Cd atom that sits in a general position, while the other bridges this Cd atom to that sitting on the twofold axis. The Cd atom located on the twofold rotation axis is linked to four equivalent CoIIIatomsviacyanide bridges, while the Cd atom that sits in a general position is connected to three equivalent CoIIIatomsviacyanide bridges. In this way, a series of trinuclear, tetranuclear and pentanuclear macrocycles are linked to form a two-dimensional network structure lying parallel to thebcplane. In the crystal structure, these two-dimensional networks are linkedviaN—H...N hydrogen bonds involving an en NH2H atom and a cyanide N atom, leading to the formation of a three-dimensional structure. This coordination polymer is only the second example involving a cyanometallate where the en ligand is present in both chelating and bridging coordination modes.


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