crystalline layer
Recently Published Documents


TOTAL DOCUMENTS

84
(FIVE YEARS 7)

H-INDEX

14
(FIVE YEARS 1)

2021 ◽  
Author(s):  
Xipeng Wang ◽  
Bo Li ◽  
Mengmeng Li ◽  
Yilong Han

Abstract Analogous to surface premelting, we propose that a crystal surface can undergo a pre-solid-solid transition, i.e. developing a thin polymorphic crystalline layer before reaching the solid-solid transition temperature if two crystals can form a low-energy coherent interface. We confirm this in simulations and colloid experiments at single-particle resolution. The power-law increase of surface layer thickness is analogous to premelting. Different kinetics and reversibilities of surface-crystal growth are observed in various systems. Surface crystals exist not only under thermal equilibrium, but also during melting, crystallization, and grain coarsening. Furthermore, the premelting and pre-solid-solid transition can coexist, resulting double surface wetting layers. We hypothesize that such surface phenomena exist in atomic and molecular crystals, which provide a novel way to tune material properties.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2756
Author(s):  
Wen-Ping Wu ◽  
Daniel Şopu ◽  
Jürgen Eckert

Amorphous/crystalline nanolaminate composites have aroused extensive research interest because of their high strength and good plasticity. In this paper, the nanoindentation behavior of Cu64Zr36/Cu amorphous/crystalline nanolaminates (ACNLs) is investigated by molecular dynamics (MD) simulation while giving special attention to the plastic processes occurring at the interface. The load–displacement curves of ACNLs reveal small fluctuations associated with shear transformation zone (STZ) activation in the amorphous layer, whereas larger fluctuations associated with dislocations emission occur in the crystalline layer. During loading, local STZ activation occurs and the number of STZs increases as the indentation depth in the amorphous layer increases. These STZs are mostly located around the indenter, which correlates to the high stresses concentrated around the indenter. When the indenter penetrates the crystalline layer, dislocations emit from the interface of amorphous/crystalline, and their number increases with increasing indentation depth. During unloading, the overall number of STZs and dislocations decreases, while other new STZs and dislocations become activated. These results are discussed in terms of stress distribution, residual stresses, indentation rate and indenter radius.


Author(s):  
A. P. Abdullayev ◽  
V. İ. Ahmadov ◽  
A. A. Isayeva

The effect of isothermal storage temperature and cooling rate on thermal processing on the maximum magnetic penetration in amorphous bands of magnetically soft [Formula: see text] alloys was studied. The dependence of maximum magnetic penetration on the isothermal storage temperature is determined using diffusion processes which occur during thermal processing at the certain isothermal storage temperatures. It is clear that increase of cooling rate directly impacts on the magnetic properties. Magnetic properties have been approached after thermal treatment of the surface when the surface is amorphous and at a certain optical thickness during formation of the amorphous-crystalline layer due to the increasing cooling speed.


Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4775 ◽  
Author(s):  
Gaopeng Wang ◽  
Shiwen Yang ◽  
Jixiang Dai ◽  
Yutang Dai ◽  
Tong Zou ◽  
...  

α-MoO3 has been used as a hydrogen sensing material due to its excellent properties and unique crystalline layer structure. However, the low repeatability of α-MoO3 based hydrogen sensor restricts its practical application. In this paper, the effect of intercalated ion species and the amount in α-MoO3 is experimentally investigated and discussed. It is concluded that the repeatability of the sensor depends on the radius of intercalated ions and amount of ionic bonds. The optimal ion species is Na+ and the optimal amount of precursor is 1 mmol.


2019 ◽  
Vol 366 (20) ◽  
Author(s):  
Adam Culka ◽  
Filip Košek ◽  
Aharon Oren ◽  
Lily Mana ◽  
Jan Jehlička

ABSTRACT Inclusions in evaporitic minerals sometimes contain remnants of microorganisms or biomarkers, which can be considered as traces of life. Raman spectroscopy with resonance enhancement is one of the best analytical methods to search for such biomarkers in places of interest for astrobiology, including the surface and near subsurface of planet Mars. Portable Raman spectrometers are used as training tools for detection of biomarkers. Investigations of the limits and challenges of detecting biomolecules in crystals using Raman spectroscopy is important because natural occurrences often involve mineral assemblages as well as their fluid and solid inclusions. A portable Raman spectrometer with 532 nm excitation was used for detection of carotenoid biomarkers: salinixanthin of Salinibacter ruber (Bacteroidetes) and α-bacterioruberin of Halorubrum sodomense (Halobacteria) in laboratory-grown artificial inclusions in compound crystals of several chlorides and sulfates, simulating entrapment of microorganisms in evaporitic minerals. Crystals of halite (NaCl), sylvite (KCl), arcanite (K2SO4) and tschermigite ((NH4)Al(SO4)2·12H2O) were grown from synthetic solutions that contained microorganisms. A second crystalline layer of NaCl or K2SO4 was grown subsequently so that primary crystals containing microorganisms are considered as solid inclusions. A portable Raman spectrometer with resonance enabling excitation detected signals of both carotenoid pigments. Correct positions of diagnostic Raman bands corresponding to the specific carotenoids were recorded.


2019 ◽  
Vol 123 (37) ◽  
pp. 23075-23081
Author(s):  
Cuiyun Zhang ◽  
Wei Chen ◽  
Junren Chen ◽  
Xiaoling Wu ◽  
Xinping Wang

2018 ◽  
Vol 268 ◽  
pp. 77-83 ◽  
Author(s):  
Kenta Iyoki ◽  
Yudai Yamaguchi ◽  
Akira Endo ◽  
Yasuo Yonezawa ◽  
Tadashi Umeda ◽  
...  

2018 ◽  
Vol 924 ◽  
pp. 128-131
Author(s):  
Taguhi Yeghoyan ◽  
Kassem Alassaad ◽  
Sean R.C. McMitchell ◽  
Marina Gutierrez ◽  
Véronique Soulière ◽  
...  

We report for the first time the successful heteroepitaxial growth of Si(100) oriented layer on top of a 3C-SiC(001) seed. By using a post-growth modification of the 3C-SiC surface (pulse insertion of precursors during cooling), it led to a change in Si nucleation, favoring squared (100) islands instead of elongated (110) ones. Without this surface modification step, the Si layers grown on 3C-SiC were always polycrystalline with a mixture of (110) and (100) orientations. Using such Si(100) layer grown on top of 3C-SiC(100), a (100) oriented 3C-SiC single crystalline layer was successfully grown on top, fabricating thus for the first time a fully (100) oriented multilayer heterostructure made of Si(substrate)/SiC/Si/SiC.


Sign in / Sign up

Export Citation Format

Share Document