scholarly journals Growth of SrB4O7 Crystal Fibers along the c-Axis by Micro-Pulling-Down Method

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 987
Author(s):  
Ryouta Ishibashi ◽  
Harutoshi Asakawa ◽  
Ryuichi Komatsu
Keyword(s):  
Solid State ◽  
Surface Morphology ◽  
Electric Fields ◽  
Growth Front ◽  
Photochemical Synthesis ◽  
Micro Machining ◽  
Density Plot ◽  
Ultraviolet Lasers ◽  
Crystal Fibers ◽  
Selection Of

SrB4O7 (SBO) receives much attention as solid-state ultraviolet lasers for micro-machining, photochemical synthesis, and laser spectroscopy. For the application of SBO, the SBO crystals require the control of twinning to amplify the conversion light. We also expected that the inhibitation of the SrB2O4 appearance was essential. Here, we show the growth of SBO crystals along the c-axis through the micro-pulling-down method while alternating the application of electric fields (E). Without the application, single crystals were grown. At E ≧ 400 V/cm no needle domains of SrB2O4 inside SBO crystals existed; however, composition planes were formed and twin boundaries did not appear. In contrast, the inversion of surface morphology emerged, and the convex size was especially large at 1000 V/cm. These results demonstrate that convection is generated perpendicular to the growth front by alternating the application of electric fields. This surface morphological change contradicts the conventional concept of growth through the micro-pulling-down method. The distance from seed crystals vs. grain density plot also showed that the density did not decrease with a sufficient slope. Consequently, we concluded that the selection of the c-axis as growth faces is not fruitful to fabricate twins, and the selection of the growth condition, under which geometrical selection strongly affects, is the key.

Current Status of Solid-State X-Ray Systems

1985 ◽  
Vol 43 ◽  
pp. 158-161
Author(s):  
Martin Peckerar ◽  
Anastasios Tousimis
Keyword(s):  
Solid State ◽  
Electric Fields ◽  
Spectral Lines ◽  
Current Status ◽  
Mobile Charge ◽  
Electron Hole ◽  
X Ray ◽  
Sensing Systems ◽  
Transmission Electron ◽  
Electron Microscopes

Solid state x-ray sensing systems have been used for many years in conjunction with scanning and transmission electron microscopes. Such systems conveniently provide users with elemental area maps and quantitative chemical analyses of samples. Improvements on these tools are currently sought in the following areas: sensitivity at longer and shorter x-ray wavelengths and minimization of noise-broadening of spectral lines. In this paper, we review basic limitations and recent advances in each of these areas. Throughout the review, we emphasize the systems nature of the problem. That is. limitations exist not only in the sensor elements but also in the preamplifier/amplifier chain and in the interfaces between these components.Solid state x-ray sensors usually function by way of incident photons creating electron-hole pairs in semiconductor material. This radiation-produced mobile charge is swept into external circuitry by electric fields in the semiconductor bulk.

Optimized growth of high length-to-diameter ratio Lu2O3 single crystal fibers by the LHPG method

CrystEngComm ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 1657-1662
Author(s):  
Na Zhang ◽  
Yuqing Yin ◽  
Jian Zhang ◽  
Tao Wang ◽  
Siyuan Wang ◽  
...  
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
High Power ◽  
Diameter Ratio ◽  
Solid State Lasers ◽  
Crystal Fibers ◽  
High Length ◽  
Length To Diameter Ratio

Lu2O3 crystals have attracted intense attention due to their great potential in the field of high power solid-state lasers.

Observation of Growth Front on the Initial Stage of Goss Abnormally-Growing Grain in Fe-3%Si Steel

2013 ◽  
Vol 753 ◽  
pp. 307-310
Author(s):  
Kyung Jun Ko ◽  
Jong Tae Park ◽  
Chan Hee Han
Keyword(s):  
Solid State ◽  
Grain Boundary ◽  
Three Dimensional ◽  
Secondary Recrystallization ◽  
Growth Front ◽  
Very High Frequency ◽  
Grain Boundary Mobility ◽  
Initial Stage ◽  
The Matrix

During abnormal grain growth, a few Goss grains grow exclusively fast and consume the matrix grains. The Goss abnormally-growing grain (AGG) has peculiar features which are irregular grain boundaries and very high frequency of peninsular grains nearby the growth front of AGG and island grains trapped inside AGG. These features might provide a clue for clarifying the mechanism of Goss AGG. The experimentally-observed microstructural feature and grain boundary characterization of Goss were approached by the solid-state wetting mechanism. In this study, observing the three-dimensional wetting morphology in serial section images of Goss AGG by EBSD, we report some direct microstrucrual evidence supporting solid-state wetting mechanism for Goss AGG. The solid-state wetting mechanism for the evolution of the Goss AGG in Fe-3%Si steel explains the microstructural features evolved during secondary recrystallization, which cannot be approached by the conventional theories based on the grain boundary mobility.

scholarly journals Optimization of Cultural Conditions for Solid State Fermentation of Amylase Production by Aspergillus species

2013 ◽  
Vol 14 (1) ◽  
pp. 67-74
Author(s):  
Bina Gautam ◽  
Tika B Karki ◽  
Om Prakash Panta
Keyword(s):  
Solid State ◽  
Rice Bran ◽  
Solid State Fermentation ◽  
Food Industry ◽  
Raw Materials ◽  
Morphological Characteristics ◽  
Amylolytic Enzyme ◽  
Cultural Conditions ◽  
Amylase Production ◽  
Selection Of

Amylase is an amylolytic enzyme used in food industry which is generally produced by Aspergillus spp. under solid state fermentation. The present study is concerned with the isolation, screening and selection of suitable strains of Aspergillus spp. and optimization of cultural conditions for the biosynthesis of amylase. Rice and wheat brans were used as substrates which are readily available inexpensive raw materials for amylase production. From 85 samples of rice and wheat grains, 55 colonies obtained on potato dextrose agar (PDA) were suspected to be Aspergillus oryzae and only 35 colonies possessed the morphological characteristics similar to that of A. oryzae indicating the isolates were most likely the strains of A. oryzae. Of all the fungal isolates of Aspergillus spps., Asp.31 gave maximum production of amylase (720.782 IUgds-1) in solid state fermentation media. This strain was selected as a parental strain for optimization for cultural conditions. The obtained data were analyzed using SPSS- 11.5 program. Of all the substrates (rice bran, wheat bran and their mixture), rice bran was the best for producing amylase of highest activity 611.614 IUgds-1.The highest enzyme activity of 698.749 IUgds-1 was observed at 50% initial moisture level of the substrate. The optimum temperature was 25°C for producing the crude amylase enzyme with amylase activity of 577.757 IUgds-1. Nepal Journal of Science and Technology Vol. 14, No. 1 (2013) 67-74 DOI: http://dx.doi.org/10.3126/njst.v14i1.8924

Surface Morphology Studies on Laser Irradiated Target and Bi(Pb)SrCaCuO Thin Films

2020 ◽  
Vol 995 ◽  
pp. 89-93
Author(s):  
A.N. Jannah ◽  
S.A. Halim ◽  
H. Abdullah
Keyword(s):  
Thin Films ◽  
Solid State ◽  
Surface Morphology ◽  
Single Crystal ◽  
Second Harmonic ◽  
Pulsed Laser ◽  
Bulk Sample ◽  
Spherical Particles ◽  
Variable Pressure ◽  
Scanning Electron

In this study, pulsed laser deposition technique was used to deposit bismuth plumbum strontium calcium copper oxide {Bi (Pb)SrCaCu0} thin films on MgO single crystal substrate. Solid state procedure which is inexpensive technique used in the production process of the Bi (Pb)SrCaCu0 superconductor bulk sample. In this work, Handy YAG Lasers (model: HYL 101 E) has been used. It is a high power class 4 solid state (ND: YAG) Q-switched pulsed laser and 532 nm (visible green: second harmonic) has been used to ablate the films. The substrate used in this work was single crystal MgO with the (100) orientation. Scanning Electron Microscopy (SEM) was used to observe the microstructure of fracture surface and cross section of thin film materials. Variable Pressure Scanning Electron Microscope (LEO-VPSEM) was used to study the correlation between the microstructure features. SEM studies have shown that the surface morphology of the bulk sample comprises platelets of average size ≈10μm with uniform and homogenous microstructure. The typical morphology of the as deposited films showed a continuous phase, granular structure, which spherical particles up to 5μm in diameter. The most prominent types of particulates BPSCCO films on MgO substrate are droplets with smooth surface, bigger droplets with granular surface, spherically-shaped features confined by randomly oriented facets, submicron rod-like features, Cu-enriched needles, platelets, irregularly-shaped Cu-rich outgrowths, strongly Cu-enriched tabular outgrowths, big target fragments, island growth structure, cubic and rectangular cubic structures. SEM analysis also showed that the deposition time have a pronounced influence on the particle size. The target morphology, which develops under laser-irradiation, depends on the laser fluence and the technique, by which the laser beam is moved relatively to the target during ablation. Laser-irradiated surfaces normally become altered both physically and chemically and morphological changes take the form of periodic structures such as ripples and ridges.

scholarly journals On the Influence of Applied Fields on Spinel Formation

1999 ◽  
Vol 586 ◽  
Author(s):  
C. Korte ◽  
J. K. Farrer ◽  
N. Ravishankar ◽  
J. R. Michael ◽  
H. Schmalzried ◽  
...  
Keyword(s):  
Thin Film ◽  
Electron Microscope ◽  
Solid State ◽  
Electric Fields ◽  
Phase Boundaries ◽  
Electron Backscattered Diffraction ◽  
Backscattered Electron ◽  
Applied Fields ◽  
Mgo Substrate ◽  
Scanning Electron

ABSTRACTInterfaces play an important role in determining the effect of electric fields on the mechanism of the formation of spinel by solid-state reaction. The reaction occurs by the movement of phase boundaries but the rate of this movement can be affected by grain boundaries in the reactants or in the reaction product. Only by understanding these relationships will it be possible to engineer their behavior. As a particular example of such a study, Mgln2O4 can be formed by the reaction between single-crystal MgO substrate and a thin film of In2O3with or without an applied electric field. High-resolution backscattered electron (BSE) imaging and electron backscattered diffraction (EBSD) in a scanning electron microscope (SEM) has been used to obtain complementary chemical and crystallographic information.

Structural Characterization of the Growth Front of 4H-SiC Boules Grown Using the Physical Vapor Transport Growth Method

2018 ◽  
Vol 924 ◽  
pp. 15-18
Author(s):  
Masashi Sonoda ◽  
Kentaro Shioura ◽  
Takahiro Nakano ◽  
Noboru Ohtani ◽  
Masakazu Katsuno ◽  
...  
Keyword(s):  
High Resolution ◽  
Surface Morphology ◽  
Defect Structure ◽  
Growth Front ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
X Ray Diffraction ◽  
X Ray ◽  
Growth Method

The defect structure at the growth front of 4H-SiC boules grown using the physical vapor transport (PVT) method has been investigated using high resolution x-ray diffraction and x-ray topography. The crystal parameters such as the c-lattice constant exhibited characteristic variations across the growth front, which appeared to be caused by variation in surface morphology of the as-grown surface of the boules rather than the defect structure underneath the surface. X-ray topography also revealed that basal plane dislocations are hardly nucleated at the growth front during PVT growth of 4H-SiC crystals.

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