Preparation and characterization of γ-La_2S_3 nanoparticles from thermal decomposition

To synthesize pure γ-La2S3 at lower temperature,lanthanide complex La（Et2S2CN）3·phen,containing La？S bond,was chosen as the precursors to decompose.The obtained samples were characterized by X-ray power diffraction （XRD）,field-emission scanning electron microscopy （FE-SEM） with an energy dispersive spectrometer and UV-Vis diffuse reflectance spectra.The decomposition mechanism of the lanthanide complex was studied by thermogravimetric analyses （TGA）.The results show that the obtained samples are cubic phase particles with sizes among 20-50 nm and the band gap is 2.97 eV,which is bigger than that of its bulk crystal.TG/DTG results indicate that La（Et2S2CN）3·phen decomposed to γ-La2S3 via La4（Et2S2CN）3 as an intermediate product.

Synthesis Characterization Non-isothermal Kinetics of the Thermal Decomposition and Redox Properties Derived from Copper(Ⅱ) Binuclear Coordination Compound of 1,4-Bis-(1'-Phenyl-3'-Methyl-5'-Pyrazolone-4')-1,4-Butanedione

The paper reports the synthetic procedure and character of Copper(II) binuclearcoordination compound of 1,4-bis-(1'-phenyl-3'-methyl-5'-pyrazolone Thenon-isothermal kinetics of thermal decomposition of the complex has been stUdied from the TG-DTGcurves by means of the Achar et al. and Coats-Redfern methods,the most probab1e kinetic equation canbe expressed as dofdtrAe -E / RT * l /(2Q).The corresponding kinetic compensation effect expressions arefound to be lnuA=0. 1794E+0. 1689.The non-isothermal thermal decomposition process of the complex isone-dimensional diffusion.But electrochemical studies of the complex(Cu2L'2)from cyclic voltamrnetriccurves by means of powder microelectrodes technique'',shows one two-electron irreversible process.

A THEORETICAL STUDY OF THE THERMODYNAMIC AND KINETIC PROPERTIES FOR THE REACTION OF FORMYL CYANIDE DECOMPOSITION

We compute the thermodynamic and the kinetic properties for the reaction: HCOCN→HCH+CO using the statistical theory and the transition-state theory.The equi- librium constants and the rate coefficients of this reaction are also reported here,and the half lives of formyl cyanide at different temperatures are first estimated in this work.

Liquid phase in-situ synthesis of LiF coated boron powder composite and performance study

Among practical metal additives,boron(B) has a high volumetric heating value,making it a promising choice as a fuel additive.Although B can theoretically yield a large amount of energy upon complete combustion,its combustion is retarded by the initial presence of B oxide,which coats the surfaces of B particle.To improve the ignition and combustion properties of B powder,LiOH and NH4F were used as precursors to synthesize uniformly LiF-coated B composites(LiF-B) in situ.The LiF-B mixture was also prepared for comparison using a physical method.X-ray diffraction(XRD),Fourier-transform infrared(FTIR),scanning electron microscope(SEM),and energy-dispersive X-ray spectroscopy(EDS) were used to characterize the morphologies and compositions of the products.The thermal and combustion properties of the samples were characterized by thermal gravity-differential thermal gravity(TG-DTG),differential scanning calo rimetry(DSC) and closed bomb experiment.The XRD,FTIR,SEM and EDS results demonstrated the successful preparation of the coated LiF-B sample.The TG-DTG and closed bomb experiment results indicated that the addition of LiF decreased the ignition temperature of B powder,and increasing its reaction efficiency.DSC results show that when LiF-B was added,the released heat of underwater explosive increased by 6727.2,7280.4 and 3109.6 J/g at heating rates of 5,10,and 15℃/min,respectively.Moreover,LiF-B decreased the activation energy of secondary combustion reaction of explosive system as calculated through Kissinger’s method by 28.9%,which indicated an excellent catalytic effect for the thermal decomposition of underwater explosive.The results reveal that LiF can improve the combustion efficiency of B powder,thereby increasing the total energy of explosives.The mechanical sensitivity increased slightly after adding LiF-B to the underwater explosive.Co mpared to the underwater explosive with added B,the mechanical sensitivity of the explosive with added LiF-B was significantly lower.

Effect of reclaimed sand additions on mechanical properties and fracture behavior of furan no-bake resin sand

In this work, the effects of reclaimed sand additions on the microstructure characteristics, mechanical properties and fracture behavior of furan no-bake resin sand have been investigated systematically within the temperature range from 25 to 600 oC. The addition of 20%-100% reclaimed sand showed dramatic strength deterioration effect at the same temperature, which is associated with the formation of bonding bridges. Both the ultimate tensile strength(UTS) and compressive strength(CS) of the moulding sand initially increase with the increase of temperature, and then sharply decrease with the further increase of temperature, which is attributed to the thermal decomposition of furan resin. The addition amount of reclaimed sand has a remarkable effect on the room temperature fracture mode, i.e., with the addition of 0-20% reclaimed sand, the fracture mode was mainly cohesive fracture; the fracture mode converts to be mixture fracture mode as the addition of reclaimed sand increases to 35%-70%; further increasing the addition to 100% results in the fracture mode of typical adhesive fracture. The fracture surface of the bonding bridge changes from a semblance of cotton or holes to smooth with the increase of test temperature.

The Finite-dimensional Decomposition Property in Non-Archimedean Banach Spaces

A non-Archimedean Banach space has the orthogonal finite-dimensional decomposition property（OFDDP） if it is the orthogonal direct sum of a sequence of finite-dimensional subspaces.This property has an influence in the non-Archimedean Grothendieck＇s approximation theory,where an open problem is the following： Let E be a non-Archimedean Banach space of countable type with the OFDDP and let D be a closed subspace of E.Does D have the OFDDP？ In this paper we give a negative answer to this question; we construct a Banach space of countable type with the OFDDP having a one-codimensional subspace without the OFDDP.Next we prove that,however,for certain classes of Banach spaces of countable type,the OFDDP is preserved by taking finite-codimensional subspaces.

Controllable hydrothermal synthesis of star-shaped Sr3Fe2（OH）12 assemblies and their thermal decomposition and magnetic properties

Pure phase star-shaped hydrogarnet Sr3Fe2（OH）12 assemblies were synthesized by a mild hydrothermal method （210℃, 12 h）, and the effects of the preparation conditions on the phase composition of the product were investigated. It was found that the impurity phases could be decreased or eliminated by increasing the molar ratio of Sr2＋ to Fe3＋, and that high temperatures favored the formation of Sr3 Fe2（OH）12 and reduced the concentration of CO32- -containing byproducts. The thermal decomposition of the star-shaped Sr3Fe2（OH）12 assemblies was examined, and the results showed that the dehydration process at higher temperatures is accompanied by the formation of SrFeO3-δ. Above 655 ℃, a solid state reaction between the SrFeO3-δ and Sr（OH）2 or SrCO3 results in the formation of Sr4Fe3O10-δ.The mag- netic properties of the as-synthesized Sr3Fe2（OH）12 and of samples calcined at different temperatures were assessed. A sample calcined at 575 ℃ exhibited greatly enhanced ferromagnetic properties, with a remanent magnetization of 1.28 emu/g and a coercivity of 4522.1 Oe at room temperature.

The Decomposability for Operator Matrices and Perturbations

Let X and Y be Banach spaces.For A∈L(X),B∈L(Y),C∈L(Y,X),let MCbe the operator matrix defined on X⊕Y by M_(C)=(AC0B)∈L(X⊕Y).In this paper we investigate the decomposability for MC.We consider Bishop’s property(β),decomposition property(δ)and Dunford’s property(C)and obtain the relationship of these properties between M_(C) and its entries.We explore how σ_(*)(M_(C))shrinks from σ_(*)(A)∪σ_(*)(B),where σ_(*)denotes σ_(β),σ_(δ),σ_(C),σ_(dec).In particular,we develop some sufficient conditions for equality σ_(*)(MC)=σ_(*)(A)∪σ_(*)(B).Besides,we consider the perturbation of these properties for MCand show that in perturbing with certain operators C the properties for MCkeeps with A,B.Some examples are given to illustrate our results.Furthermore,we study the decomposability for(0AB0).Finally,we give applications of decomposability for operator matrices.

On operator-valued Fourier multipliers

We give a simpler proof of a result on operator-valued Fourier multipliers on Lp([0, 2π]d; X) using an induction argument based on a known result when d= 1.