Existence of asymptotically almost periodic solutions and stability properties for functional difference equations

For functional difference equations with unbounded delay,we characterized the existence of totally stable and asymptotically almost periodic solution by using stability properties of a bounded solution in a certain limiting equation.

Magnetic Properties and Thermal Stability of Pr_(1-x)La_xCo_(5-y)Alloys

Pr1-xLaxCo5-y (x=0, 0.15. 0.25, 0.35,1.0, y=0.5, 0.7, 0.9, 1.0) alloys were investigated. The effect of the variation of x and y on magnetic properties and thermal stability of the alloys were studied. The magnetic properties for the Pr0.85La0.15Co4.3 and Pr0.75La0.25Co4.1 magnets are iHc=368 kA/m, Br=0.91 T, (BH)max=145.6 kJ/m3, αBr=-0.03%/℃ and iHc=568 kA/m,Br=0.8 T, (BH)max=127.2 kJ/m3,αBr,=-0.06%/℃, respectively The phase structures of as-cast alloys and magnets were

Synthesis,Structure,Luminescence and Thermal Stability Properties of a New(3,4)-Connected 2D Zn Coordination Polymer

A new zinc coordination polymer{[Zn2(ttmb)2(dca)4(H2O)].H2O}n(1.H2O)was synthesized by the reaction of 1,3,5-tris(1,2,4-triazol-1-ylmethyl)benzene(ttmb),Zn(Ⅱ)salt and sodium dicyanamide(Na(dca)).The structure of the title compound was determined by single-crystal X-ray diffraction,elemental analyses and IR spectra.1 exhibits a(3,4)-connected 2D double-layer network with the point symbol of{63}{(66}.The solid-state luminescence shows a strong emission band at 485 nm upon excitation at 384 nm.The thermal stability properties were also studied.

Chemical modification of barite for improving the performance of weighting materials for water-based drilling fluids

With increasing drilling depth and large dosage of weighting materials,drilling fluids with high solid content are characterized by poor stability,high viscosity,large water loss,and thick mud cake,easier leading to reservoir damage and wellbore instability.In this paper,micronized barite(MB)was modified(mMB)by grafting with hydrophilic polymer onto the surface through the free radical polymerization to displace conventional API barite partly.The suspension stability of water-based drilling fluids(WBDFs)weighted with API barite:mMB=2:1 in 600 g was significantly enhanced compared with that with API barite/WBDFs,exhibiting the static sag factor within 0.54 and the whole stability index of 2.The viscosity and yield point reached the minimum,with a reduction of more than 40%compared with API barite only at the same density.Through multi-stage filling and dense accumulation of weighting materials and clays,filtration loss was decreased,mud cake quality was improved,and simultaneously it had great reservoir protection performance,and the permeability recovery rate reached 87%.In addition,it also effectively improved the lubricity of WBDFs.The sticking coefficient of mud cake was reduced by 53.4%,and the friction coefficient was 0.2603.Therefore,mMB can serve as a versatile additive to control the density,rheology,filtration,and stability of WBDFs weighted with API barite,thus regulating comprehensive performance and achieving reservoir protection capacity.This work opened up a new path for the productive drilling of extremely deep and intricate wells by providing an efficient method for managing the performance of high-density WBDFs.

Micron-scale 1:5H-based precipitated phase with the lamellar structure of sintered Sm_(2)Co_(17)-based magnets and its potential application

The excellent thermal stability of magnetic properties of Sm_(2)Co_(17)-based magnets is their most impor-tant feature.However,this stability is reduced when the maximum energy product of Sm_(2)Co_(17)-based magnets is improved,which is mainly determined by the Fe/Cu distribution of the 2:17R cell and 1:5H cell boundary phases.During the demagnetization process,the Cu-rich 1:5H cell boundary phase with a width of 2-15 nm obstructs the motion of the domain walls,yielding coercivity.Herein,we report a micron-scale Cu/Zr-rich and Fe-lean 1:5H-based precipitated phase with a lamellar structure,probably induced by Sm_(2)O_(3) doping.This structure enables the separate regulation of Fe and Cu distribution for Sm_(2)Co_(17)-based magnets with Fe-rich 2:17R cell phases and Cu-rich 1:5H cell boundary phases,consid-erably optimizing the thermal stability of magnetic properties.This discovery can be further developed to produce Sm_(2)Co_(17)-based magnets with high performance and excellent thermal stability of magnetic properties.

Anti-inflammatory and membrane stabilizing properties of methyl jasmonate in rats

The present investigation was carried out to evaluate anti-inflammatory and membrane stabilizing properties of methyl jasmonate(MJ) in experimental rat models of acute and chronic inflammation.The effects of MJ on acute inflammation were assessed using carrageenan-induced rat's paw edema model.The granuloma air pouch model was employed to evaluate the effects of MJ on chronic inflammation produced by carrageenan in rats.The number of white blood cells(WBC) in pouch exudates was estimated using light microscopy.The levels of biomarkers of oxidative stress,such as malondialdehyde(MDA),glutathione(GSH) and activity of antioxidant enzymes in the exudates,were determined using spectrophotometry.The membrane stabilizing property of MJ was assessed based on inhibition of hemolysis of rat red blood cells(RBC) exposed to hypotonic medium.Our results indicated that MJ(25-100 mg·kg-1,i.p.) produced significant anti-inflammatory activity in carrageenan-induced paw edema in rats(P < 0.05).MJ reduced the volume of pouch exudates and the number of WBC in carrageenan-induced granulomatous inflammation.It also exhibited potent antioxidant and membrane stabilizing activities.In conclusion,these findings suggest the therapeutic potentials of methyl jasmonate in disease conditions associated with inflammation and its anti-inflammatory activity may be related to its antioxidant and membrane stabilizing activities.