The optimum combination of the influencing factors was: pulse voltage was 15 kV,size of air bubble was 23 μm,velocity of airflow was 0.35 L/min,and reaction time was 30 s.

Results: 4 cases (1.54%) of cast defect, 5 cases (1.92%) of fracture porcelain, 9cases (3.46%) of air bubble, 8 cases (3.1%) of unsatisfied with color.

Results:Of the made PFM restorations,there are 4 pieces with cast defect(1.54%),5 pieces with fractured porcelain (1.92%),9 pieces with air bubble (3.46%) and 8 cases with unsatisfied color(3.10%).

The functions of hemodialysis instrument include the blood circuit,the dialysate circuit,the pressure detection,the air bubble detection and temperature detection.

The tests on rising velocity of air bubble in distilled water, alcohol, and Freon 113 having different density, viscosity, and surface tension were performed.

In order to solve this problem, double seal modification, mounting air bubble equipment and dust cleaning by means of high-pressure water were carried out during the maintenance period.

The content includes the research on the formula, the testing of the adhesive intensity, the examination of heataging resistance performance, the experiment on saltyfog resistance, the property on medium resistance, the effect of coupling agent, the action of filler and the effect of air bubble's bringing and eliminating on adhesive performance.

A field experiment consisted of hydrophone recordings in a pond, 25 ft in depth, of signals transmitted through air bubble curtains from a water gun source.

Objective To evaluate the effect of continuous curvilinear capsulorrhexis (CCC) on operation of extracapsular cataract extraction(ECCE) in eyes with cataract through tension air bubble of anterior chamber. Methods CCC was performed on 122 patients receiving ECCE with intraocular lens implantation.

Experimental prevention of secretion-grooming leads to the loss of the respiratory air bubble and a significant increase in mortality.

Results of general nature, as well as for the particular case of an air bubble in water, are shown in diagrams, and several limiting cases, including the limiting case of constant pressure in the bubble, are discussed.

When air is injected into silicone oil contained in a horizontal Hele-Shaw cell, a single air bubble forms and grows showing various interesting phenomena.

The shape of an air bubble generated on a horizontal flat plate with a poorly wetted surface was predicted with the finite element method.

The dependence of the lidar return characteristics on the air bubble concentration and microstructure and of the optical and geometrical conditions of observations is examined for the radiation wavelength λ = 0.53 μm.

This paper is limited mainly to an analysis of the data presently available in the literaturc.Three topics have been investigated,namely, 1.the behavior of the resistance coefficient of an aerated flow, 2.the principal flow parameter for the correlation of data on air entrainment, and 3.the distribution of air concentration. According to Ehrenberger,the aerated flow in a channel consists of three zones of flow in addition to the zone of pure water that may possibly exist near the bed of the channel.These...

This paper is limited mainly to an analysis of the data presently available in the literaturc.Three topics have been investigated,namely, 1.the behavior of the resistance coefficient of an aerated flow, 2.the principal flow parameter for the correlation of data on air entrainment, and 3.the distribution of air concentration. According to Ehrenberger,the aerated flow in a channel consists of three zones of flow in addition to the zone of pure water that may possibly exist near the bed of the channel.These are the zone of air with water droplets,the zone of water with air bubbles,and a transition zone in between the foregoing two.In order to bring out more clearly the dynamical nature,of the flow,we propose,by analogy to sediment movement, to call the zones of air with water droplets and those of water with air bubbles respec- tively the zones of saltation and suspension. It was found that the channel inclination has a marked influence on the resistance coefficient of the flow(see fig.1).With the slope kept under a certain critical value (Straub and Anderson's data yield a critical inclination of about 30°),the Chezy co- efficient of the flow will remain the same as that of a flow without air entrainment. When the channel slope exceeds this critical value,however,an increase of the slope will cause the Chezy coefficient to increase accordingly.This is true over a certain range of Reynolds number.Beyond this range,increase in the Reynold's number will even- tually bring the Chezy coefficient back to its value for conventional water flow.An ex planation for the foregoing phenomenon has been given in the paper. Figures 2 to 4 indicate clearly that U/(g(1-)h_(99))~(1/2)is a principal flow parameter for the correlation of air-entrainment data.As this parameter is of the type of a Froude number,the foregoing statement implies that prototype phenomena of air entrainment may be reproduced in the laboratory.

The general equations of motion,mass conservation,continuity and energy are de- rived for the aerated turbulent water flow.The equations appear in the paper as Eqs.(6),(7),(8)and(12),where c denotes the air concentration and a_i the rise velo- city of air bubbles.Equation(6)differs significantly from the Reynolds equation by the appearance of the additional turbulent concentration stress The two-dimensional aerated steady uniform open channel flow is studied in detail, for which the stress equation(16)is...

The general equations of motion,mass conservation,continuity and energy are de- rived for the aerated turbulent water flow.The equations appear in the paper as Eqs.(6),(7),(8)and(12),where c denotes the air concentration and a_i the rise velo- city of air bubbles.Equation(6)differs significantly from the Reynolds equation by the appearance of the additional turbulent concentration stress The two-dimensional aerated steady uniform open channel flow is studied in detail, for which the stress equation(16)is first derived,making use of Eqs.(6),(7)and(8). It is pointed out that Eq.(16)contains the gravitational force gρ sin θ(y- which increases with the angle θ of inclination,and the concentration stresscos θ,which decreases with θ.As the velocity is influenced by these two quantities,the increase of discharge with θ should be less for the aerated open channel flow than for the nonaerated. As needed for subsequent analysis,the test values of against Y_1~′/d_s obtained from Straub and Anderson's data for the open channel flow are plotted in Figs.(5)and(6).The symbol d_s is the depth from the channel bed(y=0)to the interface(y=d_s)between the water and the air flow; and are the air concentra- tions at the bed and at the interface respectively is the corresponding sectional mean; Y_1~′ is the distance from the center of the entrained air mass to the interface. Following the two figures,the velocity-profile equations are derived by using Eq.(16) and Prandtl's mixing length(l)theory.The plane(y=d_1)of the maximum velocity is considered to divide the open channel flow into two regions:the lower region 0≤y≤d_1 near the bottom wall,and the upper region d_1≤y≤d_s near the interface, both having comparable depths.For the lower region,l=Ky is assumed as usual and a logarithmic velocity profile in the form of Eq.(24)is obtained,where u_1~* is the shear- stress velocity at y=d_1.In Eq.(23),which is used to define u_1~*,k is the ratio of - to gρ(y).For the upper region,however,the turbulence is con- sidered“free”,and the assumption l/d_s=D yields a linear velocity profile with adverse transverse gradient.As shown by Figs.7 and 8,measured velocities such as given by Straub and Lamb for different angles θ can be plotted in accordance with the two velocity equations. Using Eqs.(24)and(26),the resistance equation(30),which contains the universal constants A,K,B,D,k,d_1/d_s and /u_1~*,and expresses Chezy's C as a function of θ,Re,,is finally derived.

The broad-band absorbers for anechoic tank have been developed. Vermiculite flakes were used as filler to increase the loss and to improve the compressibility of butyl rubber, a sound absorbing material with high loss was thus obtained. By adding air bubbles in vermiculite flakes, the bulk compressive strain in rubber is changed into shear strain. Therefore, the effective loss factor of material increases with increase of the volume ratio of the bubble.Rib structures with parallel channel with total...

The broad-band absorbers for anechoic tank have been developed. Vermiculite flakes were used as filler to increase the loss and to improve the compressibility of butyl rubber, a sound absorbing material with high loss was thus obtained. By adding air bubbles in vermiculite flakes, the bulk compressive strain in rubber is changed into shear strain. Therefore, the effective loss factor of material increases with increase of the volume ratio of the bubble.Rib structures with parallel channel with total lengths of 20 cm and 15 cm (transition part being 15 cm and 10 cm respectively) have been used for the purpose of economy of the testing material. The channel width is 3 cm The reflection coefficient is less than 10% in the frequency range of 5-80kHz.