LAYERED STRUCTURE IN THE BITUNICATE ASCUS

1967 ◽  
Vol 45 (8) ◽  
pp. 1265-1266 ◽  
Author(s):  
A. Funk ◽  
R. A. Shoemaker
Keyword(s):  
Layered Structure ◽  
Multilayered Structure ◽  
Ascospore Discharge ◽  
Bitunicate Ascus

The bitunicate ascus of Botryosphaeria piceae Funk was found to have a multilayered structure of the endotunica, the hydrophylic, extensible, inner wall of the ascus that functions in ascospore discharge. A similar multilayered endotunica was observed in Botryosphaeria quercuum (Schw.) Sacc. and in Pleospora herbarum (Fr.) Rab. var. herbarum following treatment in 7% KOH solution.

Design and assessment of an acoustic ground cloak with layered structure

2015 ◽  
Vol 29 (27) ◽  
pp. 1550191 ◽  
Author(s):  
Jie Xiong ◽  
Tianning Chen ◽  
Xiaopeng Wang ◽  
Jian Zhu
Keyword(s):  
Layered Structure ◽  
Acoustic Waves ◽  
Effective Medium Theory ◽  
Incident Angle ◽  
Multilayered Structure ◽  
Assessment System ◽  
Cosine Similarity ◽  
Acoustic Beam ◽  
Medium Theory ◽  
Transformation Acoustics

In this paper, a two-dimensional acoustic ground cloak with alternating layered structure composed of mercury and water is designed on the basis of transformation acoustics and effective medium theory. The cloak exhibits excellent cloaking performance to hide an object from the detection of acoustic waves. Cosine similarity is proposed to precisely quantize and evaluate the cloaking performance, which turns out to be succinct and effective. Numerical simulations confirm that the cloak could work well in a broad frequency band in which the cloaking performance displays an oscillatory decrease with increasing frequency. In addition, the omnidirectional property, larger incident angle of the acoustic beam has the better cloaking performance, is analyzed. This multilayered structure of cloak may offer an access to fabrication simplicity and experimental demonstration. The concept of cosine similarity may be an enrichment of the assessment system for acoustic cloaks.

In situ TEM Studies of agglomeration of sub-nanometer Ru layers in Ru/C multilayers

1992 ◽  
Vol 50 (1) ◽  
pp. 256-257
Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright
Keyword(s):  
Layered Structure ◽  
Driving Force ◽  
High Energy ◽  
Superior Performance ◽  
In Situ Tem ◽  
Rayleigh Instability ◽  
Practical Applications ◽  
Transmission Electron ◽  
Diffraction Patterns

Nanometer period Ru/C multilayers are one of the prime candidates for normal incident reflecting mirrors at wavelengths < 10 nm. Superior performance, which requires uniform layers and smooth interfaces, and high stability of the layered structure under thermal loadings are some of the demands in practical applications. Previous studies however show that the Ru layers in the 2 nm period Ru/C multilayer agglomerate upon moderate annealing, and the layered structure is no longer retained. This agglomeration and crystallization of the Ru layers upon annealing to form almost spherical crystallites is a result of the reduction of surface or interfacial energy from die amorphous high energy non-equilibrium state of the as-prepared sample dirough diffusive arrangements of the atoms. Proposed models for mechanism of thin film agglomeration include one analogous to Rayleigh instability, and grain boundary grooving in polycrystalline films. These models however are not necessarily appropriate to explain for the agglomeration in the sub-nanometer amorphous Ru layers in Ru/C multilayers. The Ru-C phase diagram shows a wide miscible gap, which indicates the preference of phase separation between these two materials and provides an additional driving force for agglomeration. In this paper, we study the evolution of the microstructures and layered structure via in-situ Transmission Electron Microscopy (TEM), and attempt to determine the order of occurence of agglomeration and crystallization in the Ru layers by observing the diffraction patterns.

Effect of Losses in a Layered Structure Containing DPS and DNG Media

PIERS Online ◽  
2008 ◽  
Vol 4 (5) ◽  
pp. 546-550 ◽  
Author(s):  
João R. Canto ◽  
Sérgio A. Matos ◽  
Carlos R. Paiva ◽  
Afonso M. Barbosa
Keyword(s):  
Layered Structure

A striped pattern of snowfall and snow cover

1993 ◽  
Vol 18 ◽  
pp. 27-32
Author(s):  
Yasuaki Nohguchi ◽  
Takashi Ikarashi ◽  
Osamu Abe ◽  
Atsushi Sato
Keyword(s):  
Snow Cover ◽  
Atmospheric Turbulence ◽  
Layered Structure ◽  
Time Variation ◽  
Vertical Wall ◽  
Striped Pattern

A striped pattern can be seen by spraying ink on a vertical wall of a snow pit to observe the layered structure of a snow cover. This pattern is caused by variations of snowfall in time, particularly pauses in snowfall, and its structure is related to a kind of fractal. In this paper, we consider snowfall and snow cover from a viewpoint of fractals and show that the layered structure of snow cover is a record of fractals on atmospheric-turbulence phenomena through the time variation of snowfall.

Study on A-site Cation Doping of CaBi2Nb2O9 with Bismuth Layered Structure

2012 ◽  
Vol 27 (7) ◽  
pp. 726-730 ◽  
Author(s):  
Li-Chao ZONG ◽  
Jiang-Tao ZENG ◽  
Su-Chuan ZHAO ◽  
Wei RUAN ◽  
Guo-Rong LI
Keyword(s):  
Layered Structure ◽  
Cation Doping ◽  
A Site

Perithecium Formation and Ascospore Discharge in Fusarium graminearum

BIO-PROTOCOL ◽  
2018 ◽  
Vol 8 (15) ◽  
Author(s):  
Yan Guo ◽  
Wan-Qian Wei ◽  
Dong Zhang ◽  
Wei-Hua Tang
Keyword(s):  
Fusarium Graminearum ◽  
Ascospore Discharge

scholarly journals Synthesis, microstructure, and properties of high purity Mo2TiAlC2 ceramics fabricated by spark plasma sintering

2020 ◽  
Vol 9 (6) ◽  
pp. 759-768
Author(s):  
Yunhui Niu ◽  
Shuai Fu ◽  
Kuibao Zhang ◽  
Bo Dai ◽  
Haibin Zhang ◽  
...  
Keyword(s):  
Grain Size ◽  
Flexural Strength ◽  
Spark Plasma Sintering ◽  
Layered Structure ◽  
High Purity ◽  
High Fracture Toughness ◽  
Temperature Range ◽  
Microstructure And Properties ◽  
Plasma Sintering ◽  
Spark Plasma

AbstractThe synthesis, microstructure, and properties of high purity dense bulk Mo2TiAlC2 ceramics were studied. High purity Mo2TiAlC2 powder was synthesized at 1873 K starting from Mo, Ti, Al, and graphite powders with a molar ratio of 2:1:1.25:2. The synthesis mechanism of Mo2TiAlC2 was explored by analyzing the compositions of samples sintered at different temperatures. It was found that the Mo2TiAlC2 phase was formed from the reaction among Mo3Al2C, Mo2C, TiC, and C. Dense Mo2TiAlC2 bulk sample was prepared by spark plasma sintering (SPS) at 1673 K under a pressure of 40 MPa. The relative density of the dense sample was 98.3%. The mean grain size was 3.5 μm in length and 1.5 μm in width. The typical layered structure could be clearly observed. The electrical conductivity of Mo2TiAlC2 ceramic measured at the temperature range of 2–300 K decreased from 0.95 × 106 to 0.77 × 106 Ω–1·m–1. Thermal conductivity measured at the temperature range of 300–1273 K decreased from 8.0 to 6.4 W·(m·K)–1. The thermal expansion coefficient (TEC) of Mo2TiAlC2 measured at the temperature of 350–1100 K was calculated as 9.0 × 10–6 K–1. Additionally, the layered structure and fine grain size benefited for excellent mechanical properties of low intrinsic Vickers hardness of 5.2 GPa, high flexural strength of 407.9 MPa, high fracture toughness of 6.5 MPa·m1/2, and high compressive strength of 1079 MPa. Even at the indentation load of 300 N, the residual flexural strength could hold 84% of the value of undamaged one, indicating remarkable damage tolerance. Furthermore, it was confirmed that Mo2TiAlC2 ceramic had a good oxidation resistance below 1200 K in the air.

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