Stabilizing effect of plasma discharge on bubbling fluidized granular bed

Fluidized beds have been widely used for processing granular materials. In this paper, we study the effect of plasma on the fluidization behavior of a bubbling fluidized bed with an atmospheric pressure plasma discharger. Experiment results show that the bubbling fluidized bed is stabilized with the discharge of plasma. When the discharge current reaches a minimum stabilization current Cms, air bubbles in the bed will disappear and the surface fluctuation is completely suppressed.A simplified model is proposed to consider the effect of electric Coulomb force generated by the plasma. It is found that the Coulomb force will propel the particles to move towards the void area, so that the bubbling fluidized bed is stabilized with a high enough plasma discharge.

Fullerene bisadduct stabilizers:The effect of different addition positions on inhibiting the autocatalytic decomposition of nitrocellulose absorbed nitroglycerin

To explore the effect of different positions and number of pyrrolidine bound to the carbon cage on the stabilization effect of fulleropyrrolidine derivatives to nitrocellulose(NC)/nitroglycerine(NG),we synthesized N-(4-methoxy)phenylpyrrolidine-C_(60) and four different of bis(N-(4-methoxy)phenylpyrrolidine)-C_(60) compounds through Prato reaction.Their structures were characterized by UVevis,^(1)H NMR,^(13)C NMR,high-resolution mass spectroscopy,and single-crystal X-ray diffraction.Their stabilization effect to NC/NG were investigated using differential scanning calorimetry,methyl violet,vacuum stabilization effect,weight loss,and accelerating rate calorimeter tests.The results indicated these compounds had excellent stabilization effect to NC/NG.The stabilization effect of the fulleropyrrolidine bisadducts to NC/NG is significantly better than that of fulleropyrrolidine monoadduct and C_(60).Moreover,the position where pyrrolidine binds to fullerene in fulleropyrrolidine bisadducts is different,and its stabilization effect to NC is also different.The stabilization effect order of different bisadduct isomers to nitrocellulose is as follows:e-edge>trans-2>cis-2>trans-3.Electron paramagnetic resonance(EPR)and FT-IR were used to study the stabilization mechanism of fulleropyrrolidine derivatives to NC/NG.The EPR results also show that fulleropyrrolidine bisadducts with different addition sites have different abilities to absorb nitroxide,and their ability is better than that of the monoadduct and C_(60),which is consistent with the results of stabilization effect performance test.

EFFECT OF HYDRATION ON THE THERMAL STABILITY OF ENZYME

The thermal stability of New Zealand culture rabbit muscle aldolase was investigated by differential scanning calorimetry in the water content range 0.23-3.70 g water per g protein.The experimental results showed that at water contents below 0.47g/g,an endothermic peak was observed and at water contents above 0.57g/g,an endothermic and an exothermic peak were both observed on DSC thermogram.Thermal denaturation result of the enzyme and the relationship between two transition temperatures and water contents were first reported in this paper.Up to now we have not seen any similar reports concerning the exothermic transition.

Effect of initial nickel particle size on stability of nickel catalysts for aqueous phase reforming

The deactivation behavior by crystallite growth of nickel nanoparticles on various supports（carbon nanofibers, zirconia, Si C, α-Al2O3 and γ-Al2O3） was investigated in the aqueous phase reforming of ethylene glycol. Supported Ni catalysts of ~10 wt% were prepared by impregnation of carbon nanofibers（CNF）,Zr O2, SiC, γ-Al2O3 and α-Al2O3. The extent of the Ni nanoparticle growth on various support materials follows the order CNF ~ ZrO2〉 SiC 〉 γ-Al2O3〉〉 α-Al2O3 which sequence, however, was determined by the initial Ni particle size. Based on the observed nickel leaching and the specific growth characteristics; the particle size distribution and the effect of loading on the growth rate, Ostwald ripening is suggested to be the main mechanism contributing to nickel particle growth. Remarkably, initially smaller Ni particles（~12 nm） supported on α-Al2O3 were found to outgrow Ni particles with initially larger size（~20 nm）. It is put forward that the higher susceptibility with respect to oxidation of the smaller Ni nanoparticles and differences in initial particle size distribution are responsible for this behavior.

First-Principles Calculations of the Quantum Size Effects on the Stability and Reactivity of Ultrathin Ru (0001) Films

We carry out first-principles calculations of Ru（0001） films up to 30 monolayers （MLs） to study the quantum size effect （Q, SE） of Ru films for two cases： the freestanding Ru films and Ru films on Pt（111） substrates. Our studies show that the properties of these films （surface energy, work-function, charge density decay length in a vacuum and chemical reactivity） exhibit pronounced oscillatory behavior as a function of the film thickness, with an oscillation period of about four MLs for both cases due to the relationship of the match between the Fermi wave vector and the film thickness. Due to the localization of d-electron of Ru films, these quantum oscillations almost disappear when the thickness of the film is more than -20 ML for the free standing Ru films, while for the Ru films on Pt substrates the oscillations disappear quickly when the thickness of the film is beyond -13 ML. Our results reveal that the stability and reactivity of the Ru films could be tailored through Q, SE and the Ru bilayer grown on Pt substrates observed in the experiment is also related to the effect.

STUDY ON THE STABILITY AND STACKING INTERACTION EFFECT OF THE TERNARY M(Ⅱ)(ATP)AND PYRIDINE-LIKE LIGANDS

The stabilities of the complexes of three pyridine-like ligands with M(II)(ATP)^(2-) and M(II)(M=Ni,Co)were studied by spectrophotometry and by comparing the stability constants of the ternary complexes with these of the binary complexes.A stacking interaction between the pyridine ring and the purine ring of ATP is indicated.The general existence of the stacking interaction encourages us to interpret the antitumor mechanism of a new class of antitumor drugs.

THE EFFECT OF ACID TREATMENT ON THE STABILITY OF POLYMORPHS IN BETA ZEOLITE

The stability of beta zeollie in acid solution and the effect of acid treatment on the polymorphs in beta zeolite were studied. This zeolite is easily dealuminated by HCI treatment but its framework highly resistent to acidity.In β zeolite, polymorph A is less stable than polymorph B.The chirality of β zeolite can be modified by the method of acid treatment.

Site 0ccupancy of Alloying Elements and Their Effects on the D0_3 Phase Stability in Fe_3Al

The effects of ternary solutes Ti, Co, V, Cr, Ta, W and Mo on the D03 phase 5tability of Fe3Alintermetallics are investigated by tight-binding linear Muffin-tin orbitaI method. The predictedsite preference5 of these elements in Fe3AI are in agreement with the experimental observations.The calculated Iocal magnetic moment of Fe3AI is identical to the experimentaI. ln addition, itis found that the D03 phase stability of Fe3AI doped with Ti, V, Co and Cr depends on 'energygap- of energy band near Fermi level. while the D03 phase stability of Fe3AI doped with Ta, Wand Mo may be affected by Madelung energy.

Vinylogous Fluorine Stabilizing Effect Enables Rational Design of a Novel Donor-Acceptor Cyclopropane and Its Applications in[3+2]Cycloaddition Reaction and Ring-Opening Polymerization

Comprehensive Summary Discovery of unprecedented donor-acceptor patterns can essentially enrich the chemistry of donor-acceptor cyclopropanes.We herein introduce a concept of vinylogous fluorine stabilizing effect,which guides rational design of a novel donor-acceptor cyclopropane employing gem-difluorovinyl group as the electron donor,namely dFVCP.Application of such dFVCPs in a[3+2]cycloaddition with aldehydes and a controlled ring-opening polymerization by a Mg(OTf)2/DIPEA/C(sp3)-H initiator system have been demonstrated,providing direct access to fluorine-containing tetrahydrofurans and all-carbon main-chain polymers.

Analysis of mechanical behavior of soft rocks and stability control in deep tunnels

Due to the weakness in mechanical properties of chlorite schist and the high in situ stress in Jinping II hydropower station, the rock mass surrounding the diversion tunnels located in chlorite schist was observed with extremely large deformations. This may significantly increase the risk of tunnel instability during excavation. In order to assess the stability of the diversion tunnels laboratory tests were carried out in association with the petrophysical properties, mechanical behaviors and waterlweakening properties of chlorite schist. The continuous deformation of surrounding rock mass, the destruction of the support structure and a large-scale collapse induced by the weak chlorite schist and high in situ stress were analyzed. The distributions of compressive deformation in the excavation zone with large deformations were also studied. In this regard, two reinforcement schemes for the excavation of diversion tunnel bottom section were proposed accordingly. This study could offer theoretical basis for deed tunnel construction in similar geological condition~

ON A NEW 3D MODEL FOR INCOMPRESSIBLE EULER AND NAVIER-STOKES EQUATIONS

In this paper, we investigate some new properties of the incompressible Euler and Navier-Stokes equations by studying a 3D model for axisymmetric 3D incompressible Euler and Navier-Stokes equations with swirl. The 3D model is derived by reformulating the axisymmetric 3D incompressible Euler and Navier-Stokes equations and then neglecting the convection term of the resulting equations. Some properties of this 3D model are reviewed. Finally, some potential features of the incompressible Euler and Navier-Stokes equations such as the stabilizing effect of the convection are presented.

GPU-based discrete element simulation on flow stability of flat-bottomed hopper

In this study, the flow stability of the flat-bottomed hopper was investigated via GPU-based discrete element method(DEM) simulation. With the material height inside the hopper reducing, the fluctuation of the flow rate indicates an unstable discharge. The flow regions of the unstable discharge were compared with that of the stable discharge, a key transformation zone, where the voidage showed the largest difference between unstable and stable discharge, was revealed. To identify the relevance of the key transformation zone and the hopper flow stability, the voidage variation of the key transformation zone with material height reducing was studied.A sharp increase in the voidage in the key transformation zone was considered to be the standard for judging the unstable hopper flow, and the ‘Top–Bottom effect' of the hopper was defined, which indicated the hopper flow was unstable when the hopper only had the top area and the bottom area, because the voidage of particles in the top area and the bottom area were both variables.

EFFECTIVE STABILITY FOR NEARLY INTEGRABLE MAPPINGS WITH INTERSECTION PROPERTY

We consider a nearly integrable mapping with a fixed twist frequency. Under the intersection property and Diophantine condition we prove that the mapping possesses effective stability. In particular, the mapping considered may have different dimensions of action-angle variables in our case.

Numerical Simulation of Active Suppression of Rotating Stallin Axial Compression Systems

In the present paper, a theoretical model is proposed to analyze the transient behavior of suppression of rotating stall in axial compression systems through the use of an additional disturbance. The governing equations of the model are a set of simultaneous nonlinear first order partial differential equations,and for numerical calculations, a simple explicit time marching method can be used. The influence of system parameters on the suppression effectiveness and the interaction between rotating stall and surge have been discussed initially. The analysis of the influence of system parameters presents that both the B parameter and axisymmetric compressor characteristic have significant effect on the stabilization effectiveness of a control strategy. The effectiveness decreases as the value of B and the number of stages or stage loading of the compressor increase. It has been found that the onset flow rate of rotating stall and surge in a compression system may be different, and there is a strong interaction between these two kinds of instabilities. The onset flow rate of pure one dimensional surge depends on the value of B and axisymmetric compressor characteristic, besides the slope of the compressor characteristic.In some cases, when rotating stall which is the natural mode of instability in a compression system is suppressed, one dimensional surge can occur. It often limits the effectiveness of a control strategy to suppress rotating stall. But when surge is initiated by rotating stall, it is also possible to inhibit the occurrence of surge by suppressing rotating stall in a compression system.