scholarly journals Effect of ligand substitution in [Fe(H-trz)2(trz)]BF4 spin crossover nanoparticles

2015 ◽  
Vol 3 (1) ◽  
pp. 66-72 ◽  
Author(s):  
Iurii Suleimanov ◽  
José Sanchez Costa ◽  
Gábor Molnár ◽  
Lionel Salmon ◽  
Igor Fritsky ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transition Temperature ◽  
Coordination Compounds ◽  
Room Temperature ◽  
Spin Crossover ◽  
Magnetic Measurements ◽  
Ligand Substitution ◽  
Crossover Temperature ◽  
Transition Electron Microscopy ◽  
Transition Electron

Spin crossover iron(II) 1,2,4-triazole-based coordination compounds in the form of nanoparticles were prepared using a reverse microemulsion technique. Ligand substitution approach was applied to decrease the spin crossover temperature towards room temperature in the well-known [Fe(Htrz)2(trz)]BF4 complex. The compositions of the particles were determined by elemental analysis and thermogravimetry. The morphology was monitored by transition electron microscopy (TEM). The effect associated with the ligand substitution was investigated by optical and magnetic measurements. Transition temperature has been reduced by 33 K comparing the unsubstituted sample to that with 5 % substitution.

Strengthening of CP-Ti by Rolling at Room Temperature

2010 ◽  
Vol 667-669 ◽  
pp. 737-741
Author(s):  
Jian Hua Jiang ◽  
Yi Ding ◽  
Ai Dang Shan
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Mechanical Test ◽  
Commercial Purity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transition Electron Microscopy ◽  
Microstructure Observation ◽  
Cp Ti ◽  
Transition Electron

The effects of asymmetric and symmetric rolling at room temperature on mechanical properties and microstructure of the commercial purity Ti were investigated by means of mechanical test, optical microscopy, X-ray diffraction and transition electron microscopy. The results show that through asymmetric and symmetric rolling processes the ultimate tensile strength is substantially increased from 450 MPa to 960 MPa. Microstructure observation illustrates this variation in mechanical property is caused by the grain refinement and work hardening.

scholarly journals Synthesis, Spectroscopic and Physicochemical Characterization and Biological Activity of Co(II) and Ni(II) Coordination Compounds with 4-Aminoantipyrine Thiosemicarbazone

2005 ◽  
Vol 3 (3-4) ◽  
pp. 271-288 ◽  
Author(s):  
Ram K. Agarwal ◽  
Surendra Prasad
Keyword(s):  
Coordination Compounds ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Physicochemical Characterization ◽  
Spectral Studies ◽  
Distorted Octahedral ◽  
Infrared Spectral ◽  
Thermogravimetric Studies ◽  
Antibacterial And Antifungal

We describe the synthesis and characterization of cobalt(II) and nickel(II) coordination compounds of 4[N-(furan-2’-aldimine)amino]antipyrine thiosemicarbazone (FFAAPTS) and 4[N-(4'-nitrobenzalidene) amino]antipyrine thiosemicarbazone (4'-NO2BAAPTS). All the isolated compounds have the general composition MX2(L)(H2O) (M = Co2+or Ni2+; X = Cl, Br, NO3, NCS or CH3COO; L = FFAAPTS or 4'-NO2BAAPTS) and M(ClO4)2(L)2(M = Co2+or Ni2+; L = FFAAPTS or 4'-NO2BAAPTS). Infrared spectral studies indicate that both the thiosemicarbazones coordinate in their neutral form and they act as {N,N,S} tridentate chelating ligands. Room temperature magnetic measurements and electronic spectral studies suggest the distorted octahedral geometries of the prepared complexes. Thermogravimetric studies are also reported and the possible structures of the complexes are proposed. Antibacterial and antifungal properties of these metal-coordination compounds have also been studied.

The Obtaining of Porous Strong Ceramics from Nano-Hydroxyapatite

2008 ◽  
Vol 3 (4) ◽  
pp. 40-46
Author(s):  
Dmitriy Yu. Trufanov ◽  
Andrey V. Nomoev ◽  
Molon D. Buyatuev ◽  
Dashima Zh. Bazarova ◽  
Deleg Sangaa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Porous Ceramics ◽  
X Ray ◽  
Transition Electron Microscopy ◽  
Gas Penetration ◽  
Transition Electron ◽  
Scanning Electron

The present paper describes the possibility of strong porous ceramics preparation from hydroxyapatite nanopowders. The as-dried hydroxyapatite nanopowders were uniaxially compacted and sintered. The sintered ceramics and nanopowders were analyzed by methods of transition electron microscopy, scanning electron microscopy and X-ray phase diffraction. The ceramics gas-penetration and hardness were measured. The methods of pore control were tested. The ceramics samples with open equally dispersed pores were received; the pores and grain size is about micron and less. The results are useful for making medical implantate and membrane ceramics with controlled pores size.

scholarly journals Room Temperature Ferromagnetic and Optical Properties of Chrome Doped ZnS Nanorods Prepared by Hydrothermal Method

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Wenhua Zhao ◽  
Zhiqiang Wei ◽  
Li Zhang ◽  
Xiaojuan Wu ◽  
Xuan Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Method ◽  
Room Temperature ◽  
Single Phase ◽  
Diffuse Reflectance Spectroscopy ◽  
Magnetic Measurements ◽  
Ferromagnetic Behavior ◽  
X Ray ◽  
Pl Spectra ◽  
Cr Concentration

Cr doped Zn1-xCrxS nanorods with different concentration ratio (x=0, 0.01, 0.03, and 0.05) were successfully synthesized by hydrothermal method. The crystal microstructure, morphology, chemical composition, and optical and magnetic properties of the samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (XEDS), diffuse-reflectance spectroscopy (DRS), photoluminescence (PL) spectra, and the vibrating sample magnetometer (VSM). All the samples synthesized by this method exhibited single-phase wurtzite structure with good crystallization as demonstrated by XRD studies, which indicated that all Cr ions successfully substituted for the lattice site of Zn2+ and generated single-phase Zn1-xCrxS. DRS revealed the band gap of doped Zn1-xCrxS underwent blue shift compared to that of the bulk ZnS. PL spectra showed obvious ultraviolet emission peak at 375 nm and two blue emissions appear about 500 and 580 nm. The blue emissions intensity of doped samples improved with the increase of Cr concentration, comparing to pure ZnS. Magnetic measurements indicated that the undoped and doped ZnS nanorods exhibited well-defined ferromagnetic behavior at room temperature. The saturation magnetization weakened significantly with increasing Cr concentration comparing to pure ZnS and reached minimum for 3% Cr.

Impedance Characteristics of Electrospun Nylon-6/TiO2 Nanocomposite for Humidity Sensor

2011 ◽  
Vol 471-472 ◽  
pp. 542-547 ◽  
Author(s):  
Alireza Hosseinmardi ◽  
M. Keyanpour-Rad ◽  
F. Alikhani Hesari
Keyword(s):  
Electron Microscopy ◽  
Relative Humidity ◽  
Low Cost ◽  
Fast Response ◽  
Nylon 6 ◽  
Nano Composite ◽  
Tio2 Nanofibers ◽  
Transition Electron Microscopy ◽  
Impedance Characteristics ◽  
Transition Electron

Resistive relative humidity (RH) sensors were fabricated by nano composites of nylon-6 and titanium dioxide nanopowders. The results indicated that these sensors can be fabricated as a reliable, low cost and fast response instruments. Different percentages of nylon-6 and TiO2 were studied and average diameters of the resultant nanofibers were found the 80 to 120 nm. The nano composite of nylon-6/TiO2 nanofibers was electrospun on the interdigital gold electrode on the glass substrate. It was found that the impedance of the mat ranged from 107 Ω to 102 Ω while the relative humidity was increased from 11% RH and 97.3% at room temperature. Transition electron microscopy (TEM) and scanning electron microscopy (SEM) were used to study the morphology of the nano composite.

Synthesis and Characterization of Hierarchical Zeolite with High Mechanical Stability

2011 ◽  
Vol 217-218 ◽  
pp. 368-371 ◽  
Author(s):  
Xu Ling ◽  
Rui Liu Zong ◽  
Bin Kan Qiu
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Mechanical Stability ◽  
Three Dimensions ◽  
X Ray Diffraction ◽  
Polystyrene Spheres ◽  
Hierarchical Zeolite ◽  
Transition Electron Microscopy ◽  
Transition Electron

A hierarchical zeolite was synthesized by self-assembly of ZSM-5 nano-crystals colloid and polystyrene spheres coated with cationic poly (diallyldimethylammonium chloride). The colloidial ZSM-5 nano-crystals were first bound onto the polyelectrolyte-modified PS by electrostatic attraction, followed by centrifugation to form PS/ZSM-5 close-packed composite. After being dried and calcined to remove the organic components, the hierarchical zeolite was obtained. The X-ray diffraction, scanning electron microscopy, transition electron microscopy and N2 adsorp-tion-desorption techniques were employed to characterize the hierarchical zeolite. The results showed that the material prepared by this method was well crystallized and possessed uniform ma-cropores interconnected in three dimensions through windows. Furthermore, the hierarchical zeolite was rather mechanically stable.

scholarly journals The effect of a new route on the microstructure and property of 6063 alloy during the ECAP deformation

2021 ◽  
Vol 2125 (1) ◽  
pp. 012052
Author(s):  
Nannan Zhao ◽  
Chunyan Ban
Keyword(s):  
Electron Microscopy ◽  
Cross Sections ◽  
Work Hardening ◽  
Al Alloy ◽  
High Angle ◽  
Homogeneous Microstructure ◽  
Transition Electron Microscopy ◽  
Rotation Scheme ◽  
6063 Al Alloy ◽  
Transition Electron

Abstract The microstructures and hardness of 6063 Al alloy subjected to different ECAP route (Bc and the new route) were investigated. These two routes have different rotation scheme of a sample around its long axis between two consecutive ECAP passes: Bc route, by which sample were rotated in the same direction by 90°; the new route, by which sample were rotated in the same direction by 135°. The feature microstructures of the samples subjected to the two routes were investigated by the optical microscopy (OM) and transition electron microscopy (TEM), respectively. In comparison, the pressing by the new route produces more homogeneous microstructure with the higher fraction of high angle boundaries. Furthermore, the hardness results showed that work hardening can be observed and do not depend much on the ECAP route. However, distribution of hardness in cross-sections of samples revealed that processing to total passes number of eight by the new route improves deformation uniformity.

WO3 Nanostructures Synthesized by a Sonochemical Strategy

2009 ◽  
Vol 60-61 ◽  
pp. 16-21 ◽  
Author(s):  
Shi Bin Sun ◽  
Zeng Da Zou ◽  
Guang Hui Min
Keyword(s):  
Electron Microscopy ◽  
Tungsten Trioxide ◽  
Selective Adsorption ◽  
Morphological Evolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transition Electron Microscopy ◽  
Tungsten Hexachloride ◽  
Solvent Molecules ◽  
Transition Electron

A simple sonochemical synthesis of tungsten trioxide hydrate with various morphologies has been developed by using tungsten hexachloride (WCl6) as precursor and water, ethanol and their mixture as solvent, followed by annealing in a tube furnace. The resulting products were structurally characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transition electron microscopy (TEM) and differential thermal analysis (DTA). Results show that nanowhiskers emanating from the core of nanoparticles have been obtained with ethanol as solvent, and that nanoplates and nanosheets were formed when water and/or mixed ethanol and water was used as the solvent, respectively. The continuous changing supersaturation of tungsten trioxide may account for the formation of nanowhiskers. The formation of nanoplates or nanosheets may be associated with the selective adsorption of solvent molecules on the WO3 crystals. Due to a combination of the loss of chemical bonded water and crystal growth, the as-synthesized tungsten trioxide hydrate underwent apparent morphological evolution during thermal processing.

Coordination Compounds of Several Transition Metals with Phenyl-2-pyridyl-ketone

2008 ◽  
Vol 59 (5) ◽  
Author(s):  
Angela Kriza ◽  
Mariana Tatucu ◽  
Nicolae Stanica ◽  
Paul Gabriel Anoaica
Keyword(s):  
Transition Metals ◽  
Elemental Analysis ◽  
Coordination Compounds ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Ethanolic Solution

Cobalt (II), nickel (II), copper (II), cadmium (II), and mercury(II) complexes with phenyl-2-pyridyl-ketone as ligand were synthesized at room temperature in ethanolic solution. The donor atoms and the possible geometry of the complexes were determined by means of elemental analysis, molar conductivities, IR, electronic, and EPR spectroscopies, magnetic measurements, and thermogravimmetric analysis.

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