R11与R134a离心式制冷机组性能比较

从环保、节能、热力性能及装置等方面对化工企业使用的R11与R134a大型离心制冷机组进行比较,并对R134a离心机组在使用过程中的常见问题提出改进建议。     

Calculation of multistage thermal diffusion in a centrifugal force field

An examination is made of the theory and design of a thermocentrifugal column with a small gap, which may be used for relatively rapid, high-rate isotope concentration in the presence of a finite amount of initial gas mixture.     

Deformation of antisymmetric laminate under centrifugal force and/or thermal load

A smart blade conception has been proposed by the authors. With stretching–twisting coupling effect, the blade is twisted by centrifugal load or ambient temperature change. In this paper, the blade, simplified as a cantilevered antisymmetric laminate, is investigated by classic plate theory. An analytical scheme based on Rayleigh–Ritz (RR) method is proposed to calculate plate's deformation behavior. RR's analytical results are compared with FEM's to check the present scheme's numerical accuracy. Influence of the fiber orientation angle is discussed and the angle at which the blade twists most is found. Further analysis focusing on plate's nonlinear behavior is performed. The nonlinearity, originated with large out-plane deflection, influences the plate in two aspects: large-strain and follower force. These aspects are discussed separately in the analysis, by introducing quadric terms into strain and virtual work expressions. It is shown that for the present model, nonlinear influence must be considered at 10,000 rpm rotation speed loading, but is negligible at temperature-load below 120 K.     

Intermolecular force between monoamine oxidase B and Pseudarthria viscida (L.) using atomic force spectroscopy

Inhibition of monoamine oxidase B (MAO-B) activity by deprenyl hydrochloride (drug) and methanolic extract of Pseudarthria viscida (L.) have been studied using atomic force microscopy force–distance (AFM F–D) curves. Attractive force measured between MAO-B and kynuramine dihydrobromide (substrate) was 56.12?pN?±?8.9, between MAO-B (inhibited by drug) and substrate was 11.25?pN?±?2.6 and MAO-B (inhibited by plant extract) and substrate was 18.61?pN?±?2.9. Phytochemical analysis revealed catechin as one of the compounds in P. viscida (L.) extract and MAO-B–catechin binding sites were confirmed using in silico methods. This study is perhaps the first report of combining three techniques, namely AFM F–D curves, phytochemical and in silico analysis to measure enzyme–substrate attractive force, constituents of plant extract and position of binding sites, respectively.     

离心渗铸金属铝熔液的瞬态固化与再熔

通过分析离心力场中金属铝熔液在Al2O3短纤维多孔介质内的渗流传热,考虑了离心惯性力对铝熔液的瞬态固化与再熔的影响,建立了旋转多孔介质内的渗流传热理论模型．研究了复合管铸造工艺中不同工况下液固共融区的长度和固化率的瞬态变化规律以及流场压损的分布规律．结果表明：在Al2O3颗粒的预热温度低于铝熔化温度的条件下,当渗透前沿达到一定深度时出现液固共融,随后液固共融区随渗透过程而增长,固化率逐渐提高．随着孔隙率的减小,液固共融区的长度和固化率增大,出现共熔现象的固化率降低,复合层能达到的最大厚度减小．而随着转速的减小,液固共融区长度缩短,共熔区内的固化率水乎提高,出现共熔现象的固化率增大,复合层能达到的最大厚度减小。     

Calculation of the thermodynamic parameters of helium in a centrifugal force field

The design of cooling systems for a cryoalternator's superconducting field windings must be based on the knowledge of the distribution of the thermodynamic parameters (primarily temperature) of the helium in both its liquid and gaseous phases in centrifugal force fields. This paper proposes a set of ordinary differential equations describing the distributions. By numerically solving the set, the effects of the angular velocity of rotation, filling factor and temperature (pressure) at the axis of rotation upon the pressure, temperature and density distributions in helium in rotating vessels have been studied. Formulee for the approximation of the distributions have been obtained, which are applicable to rotation axis temperatures from 3 to 4.6 K (corresponding to saturation pressures 0.24 × 10⁵ to 1.4 × 10⁵ Pa), angular velocities of rotation from 50 to 300 rad s^?1 and filling factors from 0.1 to 0.9.     

Flow of an anomalously viscous fluid film in a centrifugal force field

We consider the flow of an anomalously viscous film along the surface of a curvilinear attachment. The deformation behavior of the liquid is described by an exponential relation. Kazan State Technological University, Russia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 69, No. 1, pp. 112–117, January–February, 1996.     

Breakup of an anomolously viscous liquid film in a centrifugal force field

An equation is obtained for the breakup radius with consideration of tipping moments and Laplacian pressure forces acting on the liquid ridge at the critical point.Notation K, n rhenological constants - density - surface tension - r current cup radius - R maximum cup radius - r_c critical radius for film breakup - ¯r=¯r=r/R dimensionless current radius - ¯r_c=r_c/R dimensionless critical radius - ₀, _c actual and critical film thicknesses - current thickness - R_r ridge radius - h₀ ridge height - h current ridge height - ₀ limiting wetting angle - current angle of tangent to ridge surface - angle between axis of rotation and tangent to cup surface - angular velocity of rotation - q volume liquid flow rate - v₁ and v meridional and tangential velocities - =4vv _lm/r,=4v_m/r dimensionless velocities - M moments of surface and centrifugal forces - M_v moment from velocity head - p_r pressure within ridge - P_vm pressure from velocity head - p_m, p_pm pressures from centrifugal force components tangent and normal to cup surface - deviation range of breakup radius from calculated value - ¯r_max, ¯r_min limiting deviations of breakup radius - _c angle of tangent to curve _c/°₀=f(¯r) at critical point - t random oscillation of ratio _c/_c Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 39, No. 1, pp. 51–56, July, 1980.     

Fabrication of alumina short fibre reinforced aluminium alloy via centrifugal force infiltration

Abstract

A new casting process for fabricating short fibre reinforced metal matrix composites via the centrifugal force infiltration of fibre preforms with molten aluminium alloys is described. The effect of processing variables, such as pouring temperature, preheated mould temperature, and time of application of centrifugal force, on the infiltration kinetics and resultant microstructure is discussed. Composites having fibre volume fractions of 4·5, 8·0, 12, and 16% were obtained via this method. Comparisons with existing infiltration technology and the mechanical properties of the composite are presented.

MST/2000     

Single-molecule imaging of the dynamic interactions between macromolecules

In recent years, the development of single-molecule detection techniques has allowed the dynamic properties of biomolecules, which are normally obscured in conventional ensemble measurements, to be measured. One of these single-molecule detection techniques allows the measurement of dissociation and association events of individual molecules to be measured. This technique is based on the unique premise that the mobility between molecules that are bound and the mobility between those that are free in solution are different. The binding of ATP at the beginning and its dissociation at the end of the hydrolysis reaction were detected at the single-molecule level in real time. In this study, we extended this technique to image the dynamic interactions between large biomolecules (protein/protein and protein/polysaccharide). The binding and dissociation of fluorescently labeled macromolecules to partner molecules fixed on a glass surface were visualized by total internal reflection fluorescence microscopy. The dynamic interactions between the proteins in two energy conversion systems, that is, signaling proteins and enzyme molecules moving on dextran, have been measured. In these systems, the dynamic interactions were sensitive to the factors determining the chemical reactions. Thus, the dynamic interactions monitored in the single-molecule measurements provided useful information to further the understanding of the underlying mechanisms of energy conversion systems.     

Investigation of the heat transfer of cryogenic fluids in a centrifugal force field

Results of an experimental investigation of heat transfer during the boiling of cryogenic fluids (nitrogen, hydrogen, helium) in a large volume in a broad range of overloads and fluid levels above the heat eliminating surface are considered.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 54, No. 3, pp. 367–374, March, 1988.     

Focusing of charged particles by electric field lenses with a pulsed voltage source

Focusing properties of a single electric field lens with a pulsed voltage source are studied by means of numerical simulation. The possibility of reducing the waist diameter of the focused particle beam by more than an order of magnitude compared to the static regime is demonstrated.     

Characterization of functionally gradient epoxy/carbon fibre composite prepared under centrifugal force

Centrifugal force was employed in order to induce a spatial gradient of fibre distribution in the epoxy/carbon fibre system. The gradient structure of the epoxy/carbon fibre composite can be controlled by varying the rotation time and the material parameters, such as fibre length, fibre content and matrix viscosity. The spatial gradient distribution of carbon fibres in an epoxy matrix was achieved by the combined mechanism of packing and settling. The mechanical properties of the functionally gradient epoxy/carbon fibre composite were also investigated. At the same content of carbon fibre, the flexural strength of the functionally gradient composite was higher than that of conventional isotropic composite. This revised version was published online in November 2006 with corrections to the Cover Date.     

reduction of equilibrium,compatibility and flexibility matrices,in the force method

This paper develops analytical expressions and numerical for reducing the structural matrices which are used in the Force Method of structural analysis. Two simple examples illustrate the calculations for pin-jointed trusses. Two advanced applications, a beam cross consisting of two coplanar beams which are linked by a shear connector, and an equilibrium linear-stress finite element, are also presented.     

Global declarations on electric vehicles,carbon life cycle and Nash equilibrium

Clean Technologies and Environmental Policy - Universal environmental policies adopt strategies that enhance and encourage the production and usage of electric vehicles (EVs). Universal cooperation...     

Fluidization of electrically conductive particles in an electric force field

Particle behavior is studied in an electrodynamically fluidized layer.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 53, No. 1, pp. 77–84, July, 1987.     

Critical heat-transfer characteristics for the boiling of helium I in a centrifugal force field

The critical heat fluxes and critical differential temperatures associated with the boiling of helium in a centrifugal force field on a flat copper heater are investigated in the range of relative accelerations 1-2280.Translated from Inzhenerno-Fizieheskii Zhurnal, Vol. 42, No. 2, pp. 207–213, February, 1982.