scholarly journals 1D-Zigzag Eu3+/Tb3+ Coordination Chains as Luminescent Ratiometric Thermometers Endowed with Multicolor Emission

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6445
Author(s):  
Luca Bellucci ◽  
Gregorio Bottaro ◽  
Luca Labella ◽  
Fabio Marchetti ◽  
Simona Samaritani ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Coordination Polymers ◽  
Thermal Sensitivity ◽  
Color Variation ◽  
Molar Ratio ◽  
Excitation Wavelength ◽  
Fixed Temperature ◽  
Physiological Temperature ◽  
Temperature Range ◽  
Temperature Ranges

Two homometallic Coordination Polymers (CPs) with composition [Ln(hfac)3bipy]n (Ln3+ = Eu3+, 1, and Tb3+, 2; hfac = hexafluoroacetylacetonato, bipy = 4,4′-bipyridine) were used to develop a family of ratiometric luminescent thermometers containing Eu3+ and Tb3+ as red and green emitters, respectively. The thermometric properties of pure CPs and of their mixtures having an Eu3+/Tb3+ molar ratio of 1:1, 1:3, 1:5, and 1:10 (samples: Eu1Tb1, Eu1Tb3, Eu1Tb5, and Eu1Tb10) were studied in the 83–383 K temperature range. Irrespective of the chemical composition, we observed similar thermometric responses characterized by broad applicative temperature ranges (from 100 to 165 K wide), and high relative thermal sensitivity values (Sr), up to 2.40% K−1, in the physiological temperature range (298–318 K). All samples showed emissions endowed with peculiar and continuous color variation from green (83 K) to red (383 K) that can be exploited to develop a colorimetric temperature indicator. At fixed temperature, the color of the emitted light can be tuned by varying composition and excitation wavelength.

Effect of Fe and Co promoters on CO methanation activity of nickel catalyst prepared by impregnation – co-precipitation method

2020 ◽  
Vol 18 (5-6) ◽  
Author(s):  
Buyan-Ulzii Battulga ◽  
Tungalagtamir Bold ◽  
Enkhsaruul Byambajav
Keyword(s):  
Synergetic Effect ◽  
Space Velocity ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Alumina Support ◽  
Co Methanation ◽  
Temperature Range ◽  
Co Precipitation ◽  
Catalyst Distribution

AbstractNi based catalysts supported on γ-Al2O3 that was unpromoted (Ni/γAl2O3) or promoted (Ni–Fe/γAl2O3, Ni–Co/γAl2O3, and Ni–Fe–Co/γAl2O3) were prepared using by the impregnation – co-precipitation method. Their catalytic performances for CO methanation were studied at 3 atm with a weight hourly space velocity (WHSV) of 3000 ml/g/h of syngas with a molar ratio of H2/CO = 3 and in the temperature range between 130 and 350 °C. All promoters could improve nickel distribution, and decreased its particle sizes. It was found that the Ni–Co/γAl2O3 catalyst showed the highest catalytic performance for CO methanation in a low temperature range (<250 °C). The temperatures for the 20% CO conversion over Ni–Co/γAl2O3, Ni–Fe/γAl2O3, Ni–Fe–Co/γAl2O3 and Ni/γAl2O3 catalysts were 205, 253, 263 and 270 °C, respectively. The improved catalyst distribution by the addition of cobalt promoter caused the formation of β type nickel species which had an appropriate interacting strength with alumina support in the Ni–Co/γAl2O3. Though an addition of iron promoter improved catalyst distribution, the methane selectivity was lowered due to acceleration of both CO methanation and WGS reaction with the Ni–Fe/γAl2O3. Moreover, it was found that there was no synergetic effect from the binary Fe–Co promotors in the Ni–Fe–Co/γAl2O3 on catalytic activity for CO methanation.

Densities and molar volumes of the Ca(NO3)2-CaBr2-H2O system

1980 ◽  
Vol 45 (1) ◽  
pp. 17-20 ◽  
Author(s):  
Zdeněk Kodejš ◽  
Ivo Sláma
Keyword(s):  
Calcium Nitrate ◽  
Molar Ratio ◽  
Molar Volumes ◽  
Temperature Range

Molar volumes and densities of mixtures consisting of water, calcium nitrate, and calcium bromide have been determined in the range of molar ratio of water within 3 to 18 and in the temperature range of 20 to 80° C. The obtained results have been described by an equation derived under the assumption that additivity of molar volumes of the components is valid.

Estimation of the Death Rate of 3T3 NIH Cell at Different Phases of the Cell Cycle in Chronic Hyperthermia within the Physiological Temperature Range

2004 ◽  
Vol 396 (1-6) ◽  
pp. 258-259 ◽  
Author(s):  
A. A. Kudryavtsev ◽  
V. P. Lavrovskaya ◽  
I. I. Popova ◽  
E. I. Lezhnev ◽  
L. M. Chailakhyan
Keyword(s):  
Cell Cycle ◽  
Death Rate ◽  
Physiological Temperature ◽  
Temperature Range

Two- and three-dimensional coordination polymers based on zinc(II) and furan-2,5-dicarboxylic acid: structure variation due to metal-to-linker ratio

2018 ◽  
Vol 74 (12) ◽  
pp. 1719-1724 ◽  
Author(s):  
Yimin Mao ◽  
Peter Y. Zavalij
Keyword(s):  
Dicarboxylic Acid ◽  
Coordination Polymers ◽  
Three Dimensional ◽  
Molar Ratio ◽  
Monoclinic Space Group ◽  
Structure Variation ◽  
Space Group ◽  
Hydrogen Bonding Pattern ◽  
Solvent Molecules ◽  
A Chain

Two ZnII-based coordination polymers (CPs) were synthesized by the hydrothermal method, using Zn(NO3)2·6H2O and furan-2,5-dicarboxylic acid (FDCA) in dimethylformamide (DMF) solvent, at 95 °C. Poly[tetrakis(dimethylazanium) [tetrakis(μ2-furan-2,5-dicarboxylato-κ2 O 2:O 5)dizinc(II)]], {(C2H8N)4[Zn2(C6H2O5)4]} n or {[DMA]4[ZnII 2(FDC)4]} n (DMA = dimethylazanium and FDC = furan-2,5-dicarboxylate), (1), was obtained with a 1:1 molar ratio of ZnII and FDCA. It crystallized in the monoclinic space group C2/c. Coordinated by ZnII ions, FDC2− ligands form 21 double-stranded helices propagating along the b axis. The helices are interconnected and extend laterally in the a direction, forming a two-dimensional (2D) sheet-like network. The 2D sheets are stacked along the c direction without interconnections. DMA cations are cocrystallized in (1) and are hydrogen bonded with carboxylate O atoms of the FDC2− ligands. The hydrogen-bonding pattern consists of R 2 2(4) and R 2 2(10) motifs alternating in a chain. Poly[bis(dimethylazanium) [bis(μ4-furan-2,5-dicarboxylato-κO 2:κO 2′:κO 5:κO 5)bis(μ3-furan-2,5-dicarboxylato-κO 2:κO 2′:κO 5)dizinc(II)] dimethylformamide 3.08-solvate], {(C2H8N)2[Zn2(C6H2O5)4]·3.08C3H7NO} n or {[DMA]2[ZnII 3(FDC)4]·3.08DMF} n , (2), was obtained with a 1:2 molar ratio of ZnII and FDCA. It crystallized in the monoclinic space group P21/c, forming a three-dimensional network. The pores are filled with DMA cations and DMF solvent molecules.

Corrosion Tests of Zircaloy Hull Waste to Confirm Applicability of Corrosion Model and to Evaluate Influence Factors on Corrosion Rate under Geological Disposal Conditions

2014 ◽  
Vol 1665 ◽  
pp. 195-202 ◽  
Author(s):  
Osamu Kato ◽  
Hiromi Tanabe ◽  
Tomofumi Sakuragi ◽  
Tsutomu Nishimura ◽  
Tsuyoshi Tateishi
Keyword(s):  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Pure Water ◽  
Influence Factors ◽  
Spent Fuel ◽  
Geological Disposal ◽  
Corrosion Tests ◽  
Temperature Range ◽  
Corrosion Rates ◽  
Temperature Ranges

ABSTRACTCorrosion behavior is a key issue in the assessment of disposal performance for activated waste such as spent fuel assemblies (i.e., hulls and end-pieces) because corrosion is expected to initiate radionuclide (e.g., C-14) leaching from such waste. Because the anticipated corrosion rate is extremely low, understanding and modeling Zircaloy (Zry) corrosion behavior under geological disposal conditions is important in predicting very long-term corrosion. Corrosion models applicable in the higher temperature ranges of nuclear reactors have been proposed based on considerable testing in the 523−633 K temperature range.In this study, corrosion tests were carried out to confirm the applicability of such existing models to the low temperature range of geological disposal, and to examine the influence of material, environmental, and other factors on corrosion rates under geological disposal conditions. A characterization analysis of the generated oxide film was also performed.To confirm applicability, the corrosion rate of Zry-4 in pure water with a temperature change from 303 K to 433 K was obtained using a hydrogen measuring technique, giving a corrosion rate for 180 days of 8 × 10-3 μm/y at 303 K.To investigate the influence of various factors, corrosion tests were carried out. The corrosion rates for Zry-2 and Zry-4 were almost same, and increased with a temperature increase from 303 K to 353 K. The influence of pH (12.5) compared with pure water was about 1.4 at 180 days at 303 K.

Tunable luminescence and white light emission of porphyrin-zinc coordination assemblies

2018 ◽  
Vol 22 (09n10) ◽  
pp. 821-830 ◽  
Author(s):  
Zheng Wang ◽  
Jian-Hua Zhang ◽  
Cheng-Yi Zhu ◽  
Shao-Yun Yin ◽  
Mei Pan
Keyword(s):  
White Light ◽  
Light Emission ◽  
Three Dimensional ◽  
White Light Emission ◽  
Molar Ratio ◽  
Excitation Wavelength ◽  
Temperature Dependent ◽  
Long Wavelength ◽  
Linear Formula ◽  
Zinc Coordination

Bipodal ligand 5,15-bis(4-carboxyphenyl) porphyrin (H[Formula: see text]DCPP) was designed and synthesized. By adjusting the molar ratio of H[Formula: see text]DCPP, ancillary ligand 4,4-bipyridine (bpy) and zinc acetate salts, three novel coordination assemblies, namely, zero-dimensional dimeric [Zn[Formula: see text](H[Formula: see text]DCPP)[Formula: see text] ·bpy] ·4H[Formula: see text]O ·4DMF (Zn-D), two-dimensional polymeric {[Zn[Formula: see text](DCPP) ·bpy[Formula: see text] ·H[Formula: see text]O ·DMF[Formula: see text]] ·solvent}[Formula: see text] (Zn-2D), and three-dimensional polymeric [Zn[Formula: see text](DCPP) ·bpy[Formula: see text]][Formula: see text] (Zn-3D) were assembled. Due to the delicate integration of multiple chromophores in the coordination space combining bpy, DCPP and MLCT emissions together, photoluminescence (PL) of the three porphyrin-zinc coordination assemblies differ from each other and color tone is tunable from blue to orange with changes of the excitation wavelength. In particular, white light emission (WLE) can be observed by the excitation of 270 to 290 nm, representing the first examples of single component WLE compounds based on porphyrin ligands. Furthermore, temperature-dependent luminescence results in a linear [Formula: see text]–[Formula: see text] relationship in Zn-2D and Zn-3D assemblies, applicable for long wavelength red-emitting thermometers.

Modeling the influence of chemical composition on compressive strength behavior of alkali-activated phosphorus slag cement using statistical design

2018 ◽  
Vol 45 (12) ◽  
pp. 1073-1083 ◽  
Author(s):  
Hamideh Mehdizadeh ◽  
Ebrahim Najafi Kani
Keyword(s):  
Compressive Strength ◽  
Chemical Composition ◽  
Statistical Design ◽  
Molar Ratio ◽  
Statistical Experimental Design ◽  
Molar Ratios ◽  
Strength Behavior ◽  
Optimum Chemical Composition ◽  
Optimum Chemical ◽  
Alkali Activated

In this study, a statistical experimental design based on response surface methodology (RSM) has been applied to predict and optimize the compressive strength of alkali-activated phosphorus slag in different ages (3, 7, and 28 days). For this purpose, the binder samples were prepared with different molar ratios of SiO2/Na2O (S/N), Na2O/Al2O3(Na/Al), and H2O/Al2O3(H/Al) as alkali activator. Results showed that S/N molar ratio plays its role in early ages of curing and Na/Al molar ratio, and showed its significant effect on 7 and 28 days of compressive strength. H/Al molar ratio had the most significant effect on compressive strength compared to the other parameters. The derived RSM models were statistically adequate and could be used to predict the compressive strength. The optimum chemical composition of activator to obtain the highest compressive strength was achieved as 0.39, 1.34, and 30 for S/N, Na/Al, and H/Al molar ratios, respectively, with compressive strength of 30, 65, and 100 MPa at 3, 7, and 28 days of curing.

scholarly journals Review on the Relationship Between Liquid Aerospace Fuel Composition and Their Physicochemical Properties

2020 ◽  
Author(s):  
Xiaoyu Wang ◽  
Tinghao Jia ◽  
Lun Pan ◽  
Qing Liu ◽  
Yunming Fang ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Physicochemical Properties ◽  
High Performance ◽  
Freezing Point ◽  
Operating Conditions ◽  
Hydrocarbon Fuels ◽  
Least Square ◽  
Fuel Properties ◽  
Molar Ratio ◽  
Fuel Composition

AbstractThe development of advanced air transportation has raised new demands for high-performance liquid hydrocarbon fuels. However, the measurement of fuel properties is time-consuming, cost-intensive, and limited to the operating conditions. The physicochemical properties of aerospace fuels are directly influenced by chemical composition. Thus, a thorough investigation should be conducted on the inherent relationship between fuel properties and composition for the design and synthesis of high-grade fuels and the prediction of fuel properties in the future. This work summarized the effects of fuel composition and hydrocarbon molecular structure on the fuel physicochemical properties, including density, net heat of combustion (NHOC), low-temperature fluidity (viscosity and freezing point), flash point, and thermal-oxidative stability. Several correlations and predictions of fuel properties from chemical composition were reviewed. Additionally, we correlated the fuel properties with hydrogen/carbon molar ratios (nH/C) and molecular weight (M). The results from the least-square method implicate that the coupling of H/C molar ratio and M is suitable for the estimation of density, NHOC, viscosity and effectiveness for the design, manufacture, and evaluation of aviation hydrocarbon fuels.

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