Luminescence of MWO4 (M =Ca, Sr, Ba and Pb) Prepared by Solvothermal Reaction

2007 ◽  
Vol 124-126 ◽  
pp. 315-318 ◽  
Author(s):  
Titipun Thongtem ◽  
Sulawan Kaowphong ◽  
Somchai Thongtem
Keyword(s):  
Propylene Glycol ◽  
Single Phase ◽  
Sodium Tungstate ◽  
Solvothermal Reaction ◽  
Scheelite Structure ◽  
Glycerol Water ◽  
Luminescent Spectra

MWO4 (M = Ca, Sr, Ba and Pb) was solvothermally prepared using metallic nitrates and sodium tungstate in 25/5 volume ratios of glycerol/water (SGL) and propylene glycol/water (SPG) at 160 oC for 6 h. XRD revealed the presence of MWO4 single phase with tetragonal scheelite structure. The strong W-O stretching band of WO4 tetrahedrons was detected at 705-875 cm-1. The product images show nano-sized particles in basic SGL and SPG solvents and flower-like particles in SPG solvent with pH of 6.7. Central peaks of the luminescent spectra are 445, 446, 443 and 440 nm, respectively.

Solvothermal Preparation of Nano-Sized CaWO4 Particles

2007 ◽  
Vol 124-126 ◽  
pp. 1265-1268 ◽  
Author(s):  
Sulawan Kaowphong ◽  
Titipun Thongtem ◽  
Somchai Thongtem
Keyword(s):  
Pure Water ◽  
Solvothermal Reaction ◽  
Hrtem Image ◽  
Scheelite Structure ◽  
Glycerol Water ◽  
Calcium Salts ◽  
Solvothermal Preparation

CaWO4 was prepared by solvothermal reaction of Na2WO4.2H2O and calcium salts (CaCl2.2H2O, Ca(NO3)2.4H2O and Ca(CH3COO)2) in solvent containing a variety of glycerol/water ratios at 160 oC for 6 h. By using XRD, SEM, TEM and ED, the products compose of nano-sized CaWO4 particles with scheelite structure but different morphologies. Interplanar spaces between (101) planes were determined from HRTEM image, ED patterns and XRD spectra are 0.424, 0.474 and 0.476 nm, respectively. Luminescent intensities of the products prepared in pure water are the highest and their central peaks are the same at 444 nm. In addition, Ca, W and O were detected using EDX.

Biphase synthesis of a one-dimensional coordination polymer based on a dinuclear CdIIsecondary building unit and a novel semi-rigid dicarboxylate

2012 ◽  
Vol 68 (12) ◽  
pp. m333-m335
Author(s):  
Xiaolai Zhang ◽  
Weiyong Ying
Keyword(s):  
Coordination Polymer ◽  
Hydrogen Bonds ◽  
Single Phase ◽  
Solvothermal Method ◽  
Solvothermal Reaction ◽  
Two Dimensional ◽  
One Dimensional ◽  
Secondary Building Units ◽  
The One ◽  
Solvothermal Conditions

A one-dimensional coordination polymer, namelycatena-poly[[aquapyridinecadmium(II)]-μ3-{4,4′-[(2,4,6-trimethyl-1,3-phenylene)bis(methylene)]dibenzoato}], [Cd(C25H22O4)(C5H5N)(H2O)]n, has been synthesized by a biphasic solvothermal reaction. The CdIIcation is located in a CdO5N six-coordinated environment. Thetrans4,4′-[(2,4,6-trimethyl-1,3-phenylene)bis(methylene)]dibenzoate ligand connects the CdIIcations to form a one-dimensional ribbon incorporating centrosymmetric [Cd2(COO)2] secondary building units. Inter-ribbon O—H...O hydrogen bonds extend the one-dimensional ribbons into a two-dimensional sheet. No π–π interactions are observed. Comparing products synthesized using a different method, it was found that biphasic solvothermal conditions play a crucial role in obtaining large well-shaped single crystals; only intractable precipitates were obtained by the traditional single-phase solvothermal method.

Phenobarbital solubility in propylene glycol-glycerol-water systems

1981 ◽  
Vol 70 (10) ◽  
pp. 1172-1174 ◽  
Author(s):  
Mamdouh A. Moustafa ◽  
Abdulla M. Molokhia ◽  
M. Wafik Gouda
Keyword(s):  
Propylene Glycol ◽  
Water Systems ◽  
Glycerol Water

Corrosion Study on Single-Phase Liquid Cooling Cold Plates with Inhibited Propylene Glycol/Water Coolant for Data Centers

2021 ◽  
pp. 1-13
Author(s):  
David Shia ◽  
Jin Yang ◽  
Sean Sivapalan ◽  
Rithi Soeung ◽  
Christian Amoah-Kusi
Keyword(s):  
Propylene Glycol ◽  
Manufacturing Process ◽  
Single Phase ◽  
Data Centers ◽  
Galvanic Corrosion ◽  
Cold Plate ◽  
Liquid Cooling ◽  
Friction Stir ◽  
Corrosion Risk ◽  
Cold Plates

Abstract Single phase cold plate based liquid cooling attracts more and more attention to high-performance computing (HPC) and general computing data centers for thermal management of modern microprocessors due to liquid's inherent advantage of higher specific heat compared to air. Deionized (DI) water is usually used as coolant for liquid cooling in data centers. On the contrary, propylene glycol/water is recommended as coolant for one-phase cold plate liquid cooling in this study for following reasons. The inhibited propylene glycol-based fluids of 25+% vol. have the benefit of being biostatic and not requiring addition of biocides. They also offer freeze protection in the usage of data centers in cold climates. The cold plates made from copper is prone to oxide even under room temperature and the dissimilarity between brazing material and copper can also cause galvanic corrosion in the usage. In this paper, a study was carried out to investigate cold plate corrosion with inhibited propylene glycol/water using design of experiments (DOE) method. This study shows manufacturing process plays an important role on corrosion risk of copper based cold plates and the corrosion risk can be mitigated by enabling new manufacturing processes, including friction stir welding (FSW) and nickel plating to the inside surface of the cold plate in the manufacturing process.

Influence of Heat Treatments on Microstructures in an Fe-Co-V Alloy

1974 ◽  
Vol 32 ◽  
pp. 512-513
Author(s):  
S. Mahajan ◽  
M. R. Pinnel ◽  
J. E. Bennett
Keyword(s):  
Single Phase ◽  
Alloy Composition ◽  
Supersaturated Solid Solution ◽  
Cell Formation ◽  
Heat Treatments ◽  
Air Cooling ◽  
Iced Brine ◽  
Transmission Electron ◽  
The Matrix ◽  
Bcc Structure

The microstructural changes in an Fe-Co-V alloy (composition by wt.%: 2.97 V, 48.70 Co, 47.34 Fe and balance impurities, such as C, P and Ni) resulting from different heat treatments have been evaluated by optical metallography and transmission electron microscopy. Results indicate that, on air cooling or quenching into iced-brine from the high temperature single phase ϒ (fcc) field, vanadium can be retained in a supersaturated solid solution (α2) which has bcc structure. For the range of cooling rates employed, a portion of the material appears to undergo the γ-α2 transformation massively and the remainder martensitically. Figure 1 shows dislocation topology in a region that may have transformed martensitically. Dislocations are homogeneously distributed throughout the matrix, and there is no evidence for cell formation. The majority of the dislocations project along the projections of <111> vectors onto the (111) plane, implying that they are predominantly of screw character.

Raman And Fluorescence Spectra Observed in Laser Microprobe Measurements of Several Compositions in the Ln-Ba-Cu-O System

1990 ◽  
Vol 48 (2) ◽  
pp. 278-279
Author(s):  
Edgar S. Etz ◽  
Thomas D. Schroeder ◽  
Winnie Wong-Ng
Keyword(s):  
Fluorescence Spectra ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Raman Microprobe ◽  
Methods Of Synthesis ◽  
Compositional Homogeneity ◽  
Processing Techniques

We are investigating by Raman microprobe measurements the superconducting and related phases in the LnBa2Cu3O7-x (for x=0 to 1) system where yttrium has been replaced by several of the lanthanide (Ln = Nd,Sm,Eu,Ho,Er) elements. The aim is to relate the observed optical spectra (Raman and fluorescence) to the compositional and structural properties of these solids as part of comprehensive materials characterization. The results are correlated with the methods of synthesis, the processing techniques of these materials, and their superconducting properties. Of relevance is the substitutional chemistry of these isostructural systems, the differences in the spectra, and their microanalytical usefulness for the detection of impurity phases, and the assessment of compositional homogeneity. The Raman spectra of most of these compounds are well understood from accounts in the literature.The materials examined here are mostly ceramic powders prepared by conventional solid state reaction techniques. The bulk samples are of nominally single-phase composition as determined by x-ray diffraction.

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