Effect of Different Solvent Ratios (Water/Ethylene Glycol) on the Growth Process of CaMoO4Crystals and Their Optical Properties

2010 ◽  
Vol 10 (11) ◽  
pp. 4752-4768 ◽  
Author(s):  
V. S. Marques ◽  
L. S. Cavalcante ◽  
J. C. Sczancoski ◽  
A. F. P. Alcântara ◽  
M. O. Orlandi ◽  
...  
2008 ◽  
Vol 43 (1) ◽  
pp. 90-96 ◽  
Author(s):  
A. Slistan-Grijalva ◽  
R. Herrera-Urbina ◽  
J.F. Rivas-Silva ◽  
M. Ávalos-Borja ◽  
F.F. Castillón-Barraza ◽  
...  

Biopolymers ◽  
1968 ◽  
Vol 6 (10) ◽  
pp. 1509-1514 ◽  
Author(s):  
G. Green ◽  
H. R. Mahler

2014 ◽  
Vol 976 ◽  
pp. 25-29
Author(s):  
Roberto Castillo-Ojeda ◽  
Joel Diaz-Reyes ◽  
Miguel Galván-Arellano ◽  
Ramon Peña-Sierra

We have studied the optical properties of GaAs and AlxGa1-xAs thin films using low-temperature photoluminescence and Fourier transform infrared spectroscopy. The GaAs and its alloys were grown by MOCVD using solid arsenic instead of arsine, as the arsenic precursor. The gallium and aluminium precursors were trimethylgallium (TMGa) and trimethylaluminium (TMAl), respectively. Some difficulties for growing AlxGa1-xAs by solid-arsenic-based MOCVD system are the composition homogeneity of the layers and the oxygen and carbon incorporation during the growth process. The composition homogeneity of the films was evaluated by low-temperature photoluminescence. Infrared measurements on the samples allowed the identification of the residual impurities, which are carbon-substitutional, Ga2O3, molecular oxygen, humidity and two unidentified impurities. Samples grown at temperatures lower than 750°C were highly resistive, independently of the ratio V/III used; the samples grown at higher temperatures were n-type, as it was proved by Hall effect measurements.


2018 ◽  
Vol 47 (5) ◽  
pp. 415-423 ◽  
Author(s):  
Yasser Assem ◽  
Heba A. Mohamed ◽  
Rana Said ◽  
Ahmed El-Masry

Purpose The purpose of this paper is to prepare amphiphilic block copolymers polyethylene adipate-block-polyethylene glycol (PEA-b-PEG)s and study their performance as plasticizers in rotogravure ink formulations. Design/methodology/approach Series of amphiphilic block copolymers (PEA-b-PEG1), (PEA-b-PEG2), (PEA-b-PEG3), (PEA-b-PEG4) and (PEA-b-PEG5) were prepared by the reaction of adipic acid, ethylene glycol and polyethylene glycol of different molecular weights (300, 1,000, 2,000, 10,000 and 20,000 g/mol), respectively. Full characterization of the prepared copolymers was achieved using Fourier Transfer Infrared Spectroscopy (FTIR), 1H NMR, thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The performance of the prepared copolymers as plasticizers for neat nitrocellulose resin were studied in different formulations, namely, R1, R2, R3, R4 and R5 containing copolymers (PEA-b-PEG1), (PEA-b-PEG2), (PEA-b-PEG3), (PEA-b-PEG4) and (PEA-b-PEG5), respectively. In addition to formula R0 that contains acetyl tributyl citrate (ATBC) as a commercial plasticizer. The mechanical properties, thermal analysis (DSC, TGA) and optical properties of the prepared formulations films were investigated. Theses amphiphilic block copolymers were then applied as plasticizers in different rotogravure ink formulations (F1, F2, F3, F4 and F5) and compared with commercial rotogravure ink formula (F0). The color measurements and optical properties of all formulations were achieved. Findings It was found that the performance of the prepared copolymers as plasticizers in different formulations based on nitro cellulose resin gives better gloss, adhesion for R1 compared with the other samples and color strength for F1 compared with F0. Finally, all the samples gave excellent plasticizing effect. Research limitations/implications The authors believe that type of these materials open the way for a new class of plasticizers that upon application or even degradation gives small ecofriendly molecules (adipic acid and or ethylene glycol moieties) taking into consideration the simplicity of the rout of the synthesis process. Practical implications The prepared ecofriendly (PEA-b-PEG)s could be successfully used as plasticizers instead of commercial plasticizer ATBC. Originality/value The research provides that the prepared (PEA-b-PEG)s with different molecular weights can act as plasticizers in rotogravure ink formulations, and their performance was acceptable and available.


Metals ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 12 ◽  
Author(s):  
Hayk Khachatryan ◽  
Sung-Nam Lee ◽  
Kyoung-Bo Kim ◽  
Moojin Kim

In this study, we deposited aluminum (Al) films of different thicknesses on steel substrate and examined their phase, microstructure, and film growth process. We estimated that films of up to 30 nm thickness were mainly amorphous in nature. When the film thickness exceeded 30 nm, crystallization was observed. The further increase in film thickness triggered grain growth, and the formation of grains up to 40 nm occurred. In such cases, the Al film had a cross-grained structure with well-developed primary grains networks that were filled with small secondary grains. We demonstrated that the microstructure played a key role in optical properties. The films below 30 nm showed higher specular reflection, whereas thicker films showed higher diffuse reflections.


RSC Advances ◽  
2015 ◽  
Vol 5 (26) ◽  
pp. 19893-19899 ◽  
Author(s):  
Jira Janbua ◽  
Jitkasem Mayamae ◽  
Supamas Wirunchit ◽  
Rattanai Baitahe ◽  
Naratip Vittayakorn

Monodispersed calcium tungstate (CaWO4) microspheres were synthesized successfully via a sonochemical process.


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