Parallel Glass Plates Research Articles

돔 유리를 이용한 위치이동 다중화 홀로그램 정보저장장치용 서보 컨트롤

위치이동 다중화 홀로그램 정보저장장치에서, 돔 형태(dome-type)유리를 이용한 서보 컨트롤 방법을 제안하였다. 5개의 2차원 데이터를 재생효율 균일도 5% 이내로 위치이동 다중화 기록을 한 후, 직경이 25.4 mm 이고 두께가 1 mm 인 돔 유리를 사용하여, 재생 시에 발생하는 홀로그램 디스크의 기울어짐 각도오차가 <TEX>$\pm$</TEX>0.2<TEX>$^{\circ}$</TEX>,위치오차 <TEX>$\pm$</TEX>50<TEX>$\mu\textrm{m}$</TEX>인 경우에 대해서도 정확한 오차보정이 가능함을 실험적으로 검증하였다. 돔 유리를 이용하는 방식은 기존에 제안된 평판유리를 이용하는 방식［김성필 외, 한국광학회지, Vol. 14, No.1, pp. 58-64, 2003］에 비해 구동이 간편하기 때문에, 서보 컨트롤을 위한 광 픽업 장치를 간단하고 작은 규모로 모듈화 하는데 매우 유용하다. We propose a servo control method using a dome-type glass in shift-multiplexed holographic data storage. We frist store live 2-D data by shift-multiplexing in a holographic disk with 5％ variation in their. diffraction efficiencies. During read-out of the stored data, the servo control using the dome glass correctly compensates mechanical errors of the disk; the error of <TEX>$\pm$</TEX>0.2<TEX>$^{\circ}$</TEX>and run-out error of <TEX>$\pm$</TEX>50 <TEX>${\mu}{\textrm}{m}$</TEX>. Use of the dome-type glass in servo control makes a pickup module more compact in size and easier to control than the previous method using parallel glass plate ［Sungphil Kim, et al., Hankook Kwanghak Hoeji, Vol. 14, No. 1, pp.58-64, 2003］.

液晶アクチュエータの基礎実験(S23-4 複雑流体の流れとその応用(4),S23 複雑流体の流れとその応用)

Experimental Study on liquid crystal actuators is performed under a polarized microscope. The low molecular weight nematic liquid crystalline material is placed between parallel glass plates. The lower plate is fixed, and the upper can move freely. When 5V of electric field is imposed on the liquid crystalline material, the rod-like molecules re-align to the orientation direction perpendicular to the plates. During this re-alignment of the liquid crystalline molecules, the fluid flow, called back-flow, is induced. Because of the back-flow mechanism, the upper glass plate moves in a certain direction.

Dynamic Deformation Capability of A Red Blood Cell under A Cyclically Reciprocating Shear Stress

Red blood cells (RBCs) in the cardiovascular devices are exposed to varying degree of the shear stress from all the directions. However the RBCs' deformability or the deformation capability under such a shear stress is not well understood. In this study, we designed and built a system that can induce a cyclically reciprocating shear stress to a RBC suspension. The arm of the cyclically reciprocating shear stress device was attached to the upper piece of the parallel glass plates between which a suspension of human RBCs (1% hematocrit whole blood diluted in a 32 weight% dextran phosphate buffer solution) was contained. The cyclic reciprocating motion of the upper glass plate of 3.0 mm stroke length was produced using a slider-crank shaft mechanism that was linked to an eccentric cam-motor system. Each rotation of the motor produced a 3.0 mm stroke each in the forward and backward direction of the slider block. The clearance between the two glass plates was adjusted to 30 micrometer. The cyclic reciprocating glass plate apparatus was attached to a light microscope stage (IX71 Olympus with x40 objective lens) for illumination with a 350 watt metal halide light source. A high speed camera (MEMREMCAM fx-K3 Nac, 5000 frames per second with shutter kept open) was attached to the microscope to capture the deformation process of the RBCs under cyclic shear stress. The preliminary result indicated that the correlation between the amplitude of the maximum shear stress and the RBCs' deformability. This indicates a potential application of the cyclic reciprocating device to evaluate the temporal response of the RBCs deformability prior to its destruction. The future study will focus on the study of the relative velocity of the erythrocytes with respect to the velocity of the reciprocating plate.

Squeeze flow of soft solids between rough surfaces

Newtonian liquids and non-Newtonian soft solids were squeezed between parallel glass plates by a constant force F applied at time t=0. The plate separation h(t) and the squeeze-rate % MathType!MTEF!2!1!+- % feaafaart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOvaiabg2 % da9iabgkHiTiqadIgagaGaaaaa!39AF! $$ V = - \dot h $$ were measured for different amplitudes of plate roughness in the range 0.3–31 μm. Newtonian liquids obeyed the relation V∝h 3 of Stephan (1874) for large plate separations. Departures from this relation that occurred when h approached the roughness amplitude were attributed to radial liquid permeation through the rough region. Most non-Newtonian materials showed boundary-slip that varied with roughness amplitude. Some showed slip that varied strongly during the squeezing process. Perfect slip (zero boundary shear stress) was not approached by any material, even when squeezed by optically-polished plates. If the plates had sufficient roughness amplitude (e.g. about 30 μm), boundary slip was practically absent, and the dependence of V on h was close to that predicted by no-slip theory of a Herschel-Bulkley fluid in squeeze flow (Covey and Stanmore 1981, Adams et al. 1994).

Advancing Contact Angles of Newtonian Fluids During “High” Velocity, Transient, Capillary-Driven Flow in a Parallel Plate Geometry

Advancing contact angles in the order of 70° to 80° were measured for Newtonian fluids at relatively high capillary numbers using a system of parallel glass plates. The transient height attained by the fluids between the plates was fitted to an averaged-flow Navier−Stokes model in order to indirectly estimate the value of the dynamic advancing angle. Subsequently, using a highly nonlinear approximation for the contact angle, it was possible to describe the entire relaxation phenomena during the capillary rise at low meniscus rates (e.g., high viscosity fluids), as well as at front velocities on the order of a hundred millimeters per second (e.g., low viscosity fluids). Contact angles obtained by the parallel plates method agree well with experimental observations and phenomenological correlations put forward in recent literature, but cannot be explained in terms of the proportionalities between dynamic angle and velocity predicted by the classical hydrodynamic and molecular theories in the nonwetting case.

Short-time dynamics of colloidal particles confined between two walls.

The short-time dynamics of colloidal particles in a quasi-two-dimensional geometry is studied by digital video microscopy. The particles (polystyrene spheres) are suspended in water and confined between two parallel glass plates, forming an effective two-dimensional system. The (effective) two-dimensional van Hove function G(r,t) and its self and distinct part are measured with a time resolution of 1/30 s. We found that the general behavior of these time-correlation functions (and their Fourier transforms) is quite similar to that of their three-dimensional counterparts. The effects of the strong hydrodynamic coupling of the particles motion to the walls and that due to the hydrodynamic interactions between particles are contained in the (effective) hydrodynamic function H(k) obtained from the initial slope of F(k,t) [the Fourier transform of G(r,t)]. We found that H(k), as a function of the wave vector k and particle concentration, exhibits a similar qualitative behavior to the hydrodynamic function in homogeneous three-dimensional suspensions of hard spheres. We also found in our systems that the particle fluctuations relax only by self-diffusion for wave vectors where the static structure factor S(k)=1. This result is important for measurements of self-diffusion dynamics in three-dimensional systems by light scattering techniques.

Constant-force squeeze flow of soft solids

Experiments are described in which the time-dependence of the sample thickness h(t) was measured for various soft solid materials squeezed between two parallel glass plates by a constant squeezing force F applied at t=0. A yield stress for each material was also measured using rotational vane and serrated parallel-plate tools. Initially, the squeeze-rate V(t)=–dh/dt of all materials was fast and resembled that of a viscous fluid. Later, most materials showed a very small squeeze-rate, and h seemed to approach a finite plate-separation limit, characteristic of a yield-stress material. For some materials h appeared not to approach a finite limit, attributed to creep or thixotropy not evident in the more rapid vane and serrated parallel-plate measurements. Expressions which relate F to h(t) and V(t) for a Herschel-Bulkley material with stick or slip at the sample-plate interface were reviewed. No materials made frictionless contact with the sample-plate interfaces, and most were best-described by the Herschel-Bulkley squeeze-flow model of Sherwood and Durban (1998). The squeeze-flow data at very low shear rate did not support the existence of Newtonian high viscosity plateaux. A soft solid of closely-packed water-swollen particles swelled when F was decreased after a period of squeeze flow, suggesting relative motion between the constituent phases. The advantages and problems of using squeeze flow as a rheometrical technique are described and discussed.

Effects of biofilm growth on flow and transport through a glass parallel plate fracture

The effects of biofilm growth on flow and solute transport through a sandblasted glass parallel plate fracture was investigated. The fracture was inoculated using soil microorganisms. Glucose, oxygen and other nutrients were supplied to support growth. The biomass initially formed discrete clusters attached to the glass surfaces, but over time formed a continuous biofilm. From dye tracer tests conducted during biofilm growth, it was observed that channels and low-permeability zones dominated transport. The hydraulic conductivity of the fracture showed a sigmoidal decrease with time. The hydraulic conductivity was reduced by a factor of 0.033, from 18 to 0.6 cm/s, corresponding to a 72% decrease in the hydraulic aperture, from 500 to 140 μm. In contrast, the mass balance aperture, determined from fluoride tracer tests, remained relatively constant, indicating that the impact of biomass growth on effective fracture porosity was much less than the effect on hydraulic conductivity. Analyses of pre-biofilm tracer tests revealed that both Taylor dispersion and macrodispersion were influencing transport. During biofilm growth, only macrodispersion was dominant. The macrodispersion coefficient α macro was found to increase logarithmically with hydraulic conductivity reduction.

F-0527 撥水表面上の微小水滴の摩擦特性(J17-3 マイクロトライボロジー&amp;プロセッシング(3))(J17 マイクロトライボロジー&amp;プロセッシング)

This paper describes the normal and tangential reaction forces of a microdroplet between two hydrophobic surfaces. Two parallel glass plates were coated with fluoric coating material in order to get hydrophobic characteristic. These surfaces show about 150° in contact angle against water droplet and l〜2μm Ra in surface roughness. The amount of water is 0.7〜6μl. With changing the distance between the two surfaces, the repulsive meniscus force and the friction force were measured and the shape of the droplet was observed. Meniscus force increases as the two surfaces get closer. Measurable maximum load capacity of 1.7μl droplet is 20mN with distance of 30μm. The meniscus force shows hysteretic characteristic and adhesive force is generated when the two surfaces are separated. On the other hand friction forces varied with respect to time. The cause of these results is considered that the water was partially held by the surface valleys when the normal load was applied.

HOE recording with non-spherical waves

A general study of third-order aberrations of aspheric holographic optical elements is described, including the effect of wavefront deviation from construction waves on the total aberration. Third-order aberration coefficients for a plane parallel glass plate referred to a general case in which the optical axes are not normal to the plate surfaces are calculated. This theoretical development is used to optimize the glass plate substrate aberration contribution in a holographic compound system used for optical image formation.

Attenuation of hypothermia-induced platelet activation and platelet adhesion to artificial surfaces in vitro by modification of hemoglobin to carry S-nitric oxide and polyethylene glycol

Hypothermic cardiopulmonary bypass alters platelet function and hypothermia is associated with postoperative myocardial ischemia. Thrombogenic surfaces such as extracorporeal circuits, vascular graft materials, and components of atherosclerotic plaque induce activation of platelets. The effects of human hemoglobin (Hb) covalently modified to carry S-nitric oxide (NO) functional groups (SNO-Hb), polyethylene glycol (PEG-Hb), and SNO–PEG-Hb on platelet activation were studied. Platelet activation was assessed by cytometric analysis of GPIIb–IIIa activation and P-selectin expression at hypothermic condition (22°C) after stimulation with Hb derivatives. Platelet adhesion and aggregation were measured in a parallel glass plate chamber coated with unmodified Hb, SNO-Hb, PEG-Hb, SNO–PEG-Hb, and collagen. Platelet binding of antibodies to GPIIb–IIIa and P-selectin was significantly enhanced by hypothermic condition and by unmodified Hb. There was significantly less platelet binding of antibodies to GPIIb–IIIa and P-selectin with SNO-Hb, PEG-Hb, and SNO–PEG-Hb compared with unmodified Hb. There was significantly less platelet attachment, adhesion, and aggregation on the SNO-Hb, PEG-Hb and SNO–PEG-Hb coated surfaces compared with unmodified Hb-coated and -uncoated surfaces. SNO-Hb, PEG-Hb, and SNO–PEG-Hb induced less platelet activation at hypothermic temperature, and induced less platelet adhesion and aggregation on thrombogenic surfaces compared with unmodified Hb. The inhibitory effect may be derived from antiadhesive properties of Hb, antiplatelet actions of NO, and molecular barrier action of PEG.

THE CAPILLARY ACTION OF WATER AS A FUNCTION OF MENISCUS LENGTH AND WETTING ANGLE.

Soil physics literature contains various expressions for the contracting force of menisci between solid soil particles. To find the most suitable expression, we measured the interaction of water and glass when one or more drops of water resided between two parallel glass plates separated by varying distances within a range of a few millimeters. Several equations were used to quantify the contracting force associated with the surface tension of water. To assess the impact of meniscus length and contact angle, we compared the force exerted by the number of individual menisci with the force exerted by the same volume of water unified in a single meniscus. Results showed that the compression of several menisci into a single meniscus reduced the contracting force. It was observed further that the attraction during the lifting phase (receding contact angle) exceeded the corresponding forces during lowering (advancing contact angle). The difference in contracting force caused by increasing meniscus length was of the same order of magnitude as the difference induced by increasing or decreasing the distance of the plates corresponding to receding or advancing contact angles. The pressure predicted, with the classical capillary equation for curved interfaces multiplied with the contact area and a modified equation, including the contact angle at the three phase line of contact, described the measured data better than the equations of either Kezdi or Bernatzik. However, in most cases, the calculated contracting force exceeded the measured values considerably. Nonlinear regression analysis showed that the closest fits were obtained when the advancing angle of about 20°, measured on smooth glass plates, was adjusted to values of about 40 to 90°. This result supports the hyphothesis that either contact angle hysteresis or the meniscus length have a considerable impact on capillary pressure and attractive forces in partly saturated capillaries.

Detachment of Aeromonas hydrophila and Pseudomonas aeruginosa due to variations in nutrient supply

Growth and detachment rates of Aeromonas hydrophila and Pseudomonas aeruginosa were measured to determine if nutrient depletion causes detachment of attached cells. A glass parallel plate, continuous observation flow cell placed on a phase contrast microscope was used to monitor bacterial behaviour on the surface under defined flow and mass transfer conditions. Shear stress was held constant at 3 N m−2. Images were taken every 15 minutes, and digital image analysis was used to quantify specific growth, detachment and accumulation rates for the attached organisms. An observable parameter proportional to the nutrient depletion at the surface was used to determine the effect of nutrient depletion on detachment rates. Increases in the depletion parameter corresponded with increases in detachment rate after the cells were rod, but the depletion parameter was not scaleable between different experiments. These experiments showed that as nutrients were depleted, detachment increased. If the detachment mechanism postulated in this work is more universal and applicable to other microbial species, new methods of detachment control through dynamic changes of nutrient supply might be devised.

FRIEZE PATTERNS FOR REGULAR STAR POLYTOPES AND STATISTICAL HONEYCOMBS

Much has been written about the discovery by physicists of quasicrystals and the almost simultaneous discovery by geometers of nonperiodic tessellations and honeycombs. A somewhat similar serendipity occurred when crystallographers saw what happens when identical balls of plastic clay or lead shot are shaken together and uniformly compressed, or when the bubbles (all of the same size) in a froth are measured; and almost simultaneously geometers investigated statistical honeycombs. Alternate doses of oil and water in a thin tube may be regarded as a one-dimensional "froth" {∞}, each "bubble" having just 2 neighbours. Analogously, soapsuds sandwiched between parallel glass plates (close together) may be regarded as a two-dimensional froth {6,3}, each bubble having just 6 neighbours. Three-dimensional froth presents a far more difficult problem because there is no regular honeycomb having 4 cells at each vertex. The best available substitute seems to be a "statistical" honeycomb {p, 3,3} where p, instead of being rational, is a real number such as π/ arctan \(\sqrt {\frac{1}{2}} \), somewhere between 5 and 6. ({5,3,3} is the regular 120-cell and {6,3,3} is non-Euclidean.) In such a statistical honeycomb, the number of neighbours for each bubble is 13.4, in good agreement with experiments in which the actual number is 12 or 14 and sometimes 15, but most often 13. Hoping not to be too fanciful, we venture to look for a statistical honeycomb {q,3,3,3} in Euclidean 4-space, q being a real number such as π/ arctan \(\sqrt {\frac{3}{5}} \), somewhere between 4 and 5. ({4,3,3,3} is the 5-cube while {5,3,3,3} is non-Euclidean.) In this case the number of neighbours for one bubble in the 4-dimensional froth is computed to be about 28.

Shear flow effect on phase behavior and morphology in polymer blends

The effect of simple shear flow on the phase behavior and morphology was investigated for both polystyrene/poly(vinyl methyl ether) (PS/PVME) and poly(methyl methacrylate)/poly(styrene-co-acrylonitrile) (PMMA /SAN-29.5) blends, which have LCST (lower critical solution temperature)-type phase diagram. The measurements were carried out using a special shear apparatus of two parallel glass plates type. The PS/PVME blends showed shear-induced demixing and shear-induced mixing at low and high shear rate values, respectively. In addition, the rotation speed and the sample thickness were found to have a pronounced effect on the phase behavior under shear flow. On the-other hand, PMMA/SAN blend showed only shear-induced mixing and the magnitudes of the elevation of the cloud points were found to be composition and molecular weight dependent. The morphology of the PMMA/SAN=75/25 blend indicated that shear-induced mixing occurred at a critical shear rate value, below which the two phases were highly oriented and elongated in the flow direction.

Shape measurements of mirror surfaces with a lateral-shearing interferometer during machine running

A common path lateral-shearing interferometer with a minimum number of optical components has been developed. Because the interferometer is little affected by mechanical vibrations and air turbulence, it can be mounted on an ultraprecision lathe and can be used to measure the shapes of workpieces. A plane parallel glass plate is used to shear the wavefront under test in the interferometer. To analyze the interference fringes obtained by the interferometer precisely, a fringe-scanning method using a slight tilt of the glass plate is used. Zone plates that are computer-generated holograms are used to measure spherical and aspherical surfaces with the interferometer. A spherical and a parabolic concave mirror were measured with the interferometer. The spherical mirror was also measured by a Fizeau interferometer to compare the error with that measured by the lateral-shearing interferometer. The experimental results agreed well with those measured by the lateral-shearing interferometer.

Effects of cell structure on the reflection of cholesteric liquid crystal displays

Cholesteric liquid crystal displays employ cells consisting of parallel glass plates which have indium-tin-oxide coating as the electrode and polyimide as the alignment layer. We have performed a systematic study of the reflections from the interfaces and the liquid crystal. We measured the reflection spectra using various incident light, various polarizations, and detection polarizations. Using the Berreman 4×4 method, we simulated the reflection spectra without fitting parameters; the results agreed well with the experimental results.

Detachment of biofilm bacteria due to variations in nutrient supply

Growth and detachment rates of an environmental isolate of Aeromonas hydrophila attached to a surface were determined under varying nutrient supply conditions in a complex medium. Growth and detachment of cells were observed in real time using phase contrast microscopy in glass parallel plate flow chambers. Surface shear stress was controlled in all experiments at 3 N m−2. Images were taken every 15 min. Digital image analysis was used to determine specific growth and detachment rates. An observable parameter proportional to the nutrient depletion at the surface due to transfer limitations was used to indicate nutrient limitations. Specific detachment rates increased as the depletion parameter increased, indicating that nutrient limitations cause this bacterium to detach at greater rates.

Detachment of biofilm bacteria due to variations in nutrient supply

Growth and detachment rates of an environmental isolate of Aeromonas hydrophila attached to a surface were determined under varying nutrient supply conditions in a complex medium. Growth and detachment of cells were observed in real time using phase contrast microscopy in glass parallel plate flow chambers. Surface shear stress was controlled in all experiments at 3 N m-2. Images were taken every 15 min. Digital image analysis was used to determine specific growth and detachment rates. An observable parameter proportional to the nutrient depletion at the surface due to transfer limitations was used to indicate nutrient limitations. Specific detachment rates increased as the depletion parameter increased, indicating that nutrient limitations cause this bacterium to detach at greater rates.

Characteristics of a laser plasma induced by irradiation of a normal-oscillation YAG laser at low pressures

The generation of a laser-induced shock wave plasma in air at reduced pressure was achieved by focusing a normal-oscillation Nd:YAG laser on a brass sheet. The characteristics of the plasma were analysed under three different conditions: free expansion of the plasma, confinement of the plasma by limiting the plasma region using two parallel glass plates and interruption of the plasma by placement of a wedge in front of the plasma, in order to interrupt the expansion of the plasma. Spatially and temporally integrated methods were also developed in order to develop a more detailed understanding of the excitation mechanism of the plasma. Furthermore, a new technique of shadow graphing which involves the use of a He - Ne laser as a probe light was also developed as well as a measurement of the time profile of the temperature. By using this new method the relationship between the density jump and the starting point of atomic emission was detected simultaneously. The results show that the plasma was also generated by the shock wave as for the case of the short-pulse laser (Q switched). The extremely low ion and background emission, as low as compared with neutral emission, makes this plasma potentially useful for spectrochemical analysis.