On the thermal-creep flow of a binary gas mixture over a plane wall with imperfect accommodation

The thermal-creep flow of a binary gas mixture over a plane wall is investigated analytically on the basis of the linearized Boltzmann equation of BGK type under the boundary condition of Maxwell's type or diffuse-specular reflection type. By an accurate analysis of the Knudsen layer formed near the wall, the Knudsen-layer structure of the velocity field has been clarified and, hence, the velocity distribution over the whole flow region is given explicitly together with the macroscopic slip coefficient. For future comparison with experimental data which may become available, the values of the slip coefficient of thermal-creep flow for several pairs of gases, Ne-Ar, He-Ne, He-Ar, N₂-Ar and N₂-O₂ are also given and listed in Table together with the values calculated based on the result given by other authors.     

Mechanism of catalytic reduction of NO by H2 or CO on a Pd foil; Role of chemisorbed nitrogen on Pd

The adsorption of NO and its reaction with H₂ over polycrystalline Pd were investigated using flash desorption technique and ultraviolet photoelectron spectroscopy under 10^?5 Pa pressure range of reactants and surface temperatures between 300 and 900 K. NO was adsorbed dissociatively onto the Pd surface above 500 K, and the heat of dissociative adsorption was ca. 126 kJ/mol. Atomic nitrogen was observed to accumulate on the Pd surface during the NO-H₂ reaction, whose desorption rate exhibited second order kinetics and is expressed as follows: V_d = 10^{?9.8 ± 0.3}exp(?67(kJ/mol)/RT) (cm²/atom·s). Hydrogenation of the adsorbed nitrogen proceeded rapidly at 485 K. It was confirmed from these results that formation of N₂ and NH₃ in the NO-H₂ reaction proceeds through this atomically adsorbed nitrogen. Pd-N bond energy and enthalpies of some intermediate states of the NO-H₂ reaction were estimated.     

Development of novel fast-disintegrating tablets by direct compression using sucrose stearic acid ester as a disintegration-accelerating agent

It was attempted to produce novel furosemide (FS) fast-disintegrating tablets by direct compression. The combination of FS, microcrystalline cellulose, croscarmellose sodium and xylitol was used as the basic formulation, and sucrose stearic acid ester (SSE) was chosen as an additional additive. The tablets with SSE were prepared by the simple addition of SSE, using a lyophilized mixture of FS and SSE or using a FS/SSE mixture obtained by evaporation of their ethanol solution. Only the tablets, produced using the FS/SSE mixture obtained by organic solvent (ethanol) evaporation, showed hardness of more than 30 N and a disintegration time of less than 20 s, which were the properties suitable for fast-disintegrating tablets. These properties were considered to result from well-mixed and fine-powdered SSE and FS.     

Influence of pectins on preparation characteristics of lactoferrin bioadhesive tablets

For the treatment of chronic inflammation in the oral cavity, we attempted to develop bioadhesive tablets of bovine lactoferrin (B-LF). Pectin was used as a bioadhesive polymer, and the influence of the degree of esterification and the molecular weight of pectins on the characteristics of B-LF tablets were investigated. Concerning bioadhesive force, a tendency increasing the value according to increase of the esterification of the pectin was confirmed. Sustained release of B-LF from the tablets was observed as the esterification increased, and a possibility for prediction of the time required to release 50% of B-LF by using the equation given by the degree of esterification and the logarithm of the molecular weight was suggested. Pectin cross-linked with Ca(2+) (Ca-PC) was also used for the preparation of the B-LF tablets. Prolonged release of B-LF from the tablets was observed as the Ca(2+) in Ca-PC increased. Our findings suggest that pectin with a high degree of esterification is suitable as a bioadhesive polymer since high bioadhesive force and sustained release are shown. Furthermore, a possibility that the B-LF release could be controlled by adjusting the Ca(2+) concentration in Ca-PC was suggested.     

Water-Nafion equilibria. absence of Schroeder's paradox

Water-Nafion phase equilibria and proton conductivities were measured in two ways. First, Nafion was in contact with saturated water vapor. Second, Nafion was in contact with liquid water at the same temperature. At 29 degrees C, for preboiled, vapor-equilibrated Nafion exposed to water with an activity = 1 and air pressures ranging from 0 to 0.96 bar, the water content was lambda = 23 +/- 1 mol H(2)O/mol SO3-. For the preboiled, liquid-equilibrated membrane, lambda = 24 +/- 2. At 100% relative humidity (RH), the water content of preboiled Nafion decreased as the temperature rose from 30 to 80 degrees C but did not recover its initial water content when the temperature returned to 30 degrees C. The water content of predried Nafion at 1 atm and 30 degrees C was lambda = 13.7 +/- 0.2 when vapor-equilibrated and lambda = 13.1 +/- 0.5 when liquid-equilibrated. A Nafion membrane originally boiled in water had much higher liquid- and 100% RH vapor-equilibrated proton conductivities than the same membrane originally dried at 110 degrees C with a RH less than 2%. The liquid-equilibrated and 100% RH vapor-equilibrated membrane conductivities were the same when the membrane had the same thermal history. The conductivity data was fit to a model, and the water content was determined at different temperatures. The predried membrane water content increased with temperature, and the preboiled membrane's water content changed slightly with temperature. Both water sorption and proton-conductivity data do not exhibit Schroeder's paradox. These studies and previous results suggest that Schroeder's paradox is resolved when attention is given to the thermal history of the absorbing polymer.     

Linear and nonlinear inversion schemes to retrieve collision kernel values from droplet size distribution change

This study presents an attempt to retrieve collision kernel values from changes in the droplet size distribution due to collision growth. Original linear and nonlinear inversion schemes are presented, which use the simple a priori assumption that the total collision rate is given by the sum of the gravitational and turbulent contributions. Our schemes directly handle binned (discretized) size distributions and, therefore, do not require any assumptions on distribution functional forms, such as the self-similarity assumption. To validate the schemes, three-dimensional direct numerical simulation (DNS) of colliding droplets in steady isotropic turbulence is performed. In the DNS, air turbulence is calculated using a pseudo-spectral method, while droplet motions are tracked by the Lagrangian method. Comparison between the retrieved collision kernels and the collision kernels obtained directly from the DNS show that for low Reynolds number flows both the linear and nonlinear inversion schemes give good accuracy. However, for higher Reynolds number flows the linear inversion scheme gives significantly larger retrieval errors, while the errors for the nonlinear scheme remain small.     

Discovery of the First 2- State in 16C via Neutron Knockout Reaction

The ¹⁶C nucleus has been investigated by the neutron knockout reaction of ¹⁷C on a liquid hydrogen target. Applying the invariant mass method in inverse kinematics and γ-ray spectroscopy, the energy spectrum was reconstructed by triple-coincidence measurement, in which neutrons, charged fragments, and γ rays from the decay of the reaction residue (¹⁶C*) were detected. A peak at 0.47 MeV was observed in the invariant mass spectrum in coincidence with a peak at 0.74 MeV in the γ-ray spectrum, which indicates the presence of an unbound state with an excitation energy of 5.46 MeV. Comparison of the experimental cross section with the value derived by a theoretical calculation provided evidence that the spin-parity of this state is 2^?.     

Dynamic Investigation of Mechanism of Catalytic Reactions as Revealed by Spectroscopic Techniques

The study of chemisorption of gases on catalyst surfaces is of primary importance in elucidating the mechanism of heterogeneous catalysis. Accordingly, the adsorption of each of the gases which participate in the catalysis has been studied separately in many cases. However, chemisorption on the catalyst surface during the progress of reaction, generally speaking, cannot be estimated from the adsorption equilibrium of reactants and products measured separately for each species, but depends upon the mechanism of the reaction, the interaction among the adsorbed species, the formation of reaction intermediates or surface complexes, and the area of active region on the surface.     

Reflection absorption infrared spectroscopy analysis of the evolution of ErSb on InSb

We discuss an ex-situ monitoring technique based on glancing-angle infrared-absorption used to determine small amounts of erbium antimonide (ErSb) deposited on an indium antimonide (InSb) layer epitaxially grown on an InSb (100) substrate by low pressure metal organic chemical vapor deposition (MOCVD). Infrared absorption from the indium–hydrogen (InH) stretching mode at 1754.5 cm^? 1 associated with a top most surface of an epitaxial InSb layer was used to compare varying levels of surface coverage with ErSb. Among four samples of varying coverage of ErSb deposition (7.2 to 21.5 monolayers), detected infrared absorption peaks distinct to InH weakened as ErSb surface coverage increased. In the early stage of ErSb deposition, our study suggests that outermost indium atoms in the InSb buffer layer are replaced by Er resulting in increase in absorption associated with the InH mode. Using this simple ex-situ technique, we show that it is possible to calibrate the amount of ErSb deposited atop each individual InSb substrate for depositions of few to tens of monolayers.     

FM-AFM imaging of a commercial polyethylene film immersed in n-dodecane

The subnanometer topography of a partially crystalline polyethylene film was observed in liquid n-dodecane using a frequency-modulation atomic force microscope. Locally ordered structures were found and assigned to a (100) facet of crystalline domains.