Shear viscosity of the B phase of superfluid 3He. II. s-p-d-wave approximation

The shear viscosity (T) of superfluid ³He-B is studied throughout the temperature region 0t1 (t=T/T _c). The Boltzmann equation for Bogoliubov-Valatin quasiparticles is solved by a variational method. In the calculation of the collision integral, the scattering amplitude is estimated in the s-p-d-wave approximation by taking into account the spin-dependent part as well as the spin-independent part. The reduced shear viscosity % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-qqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xHapdbiqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaacaaeaacq% aH3oaAaiaawoWaaiabg2da9iabeE7aOHqaciaa-HcaieaacaGFubGa% a8xkaGGaciab99caViabeE7aOjaa-HcacaGFubWaaSbaaKqaGgaaca% WFJbaaleqaaOGaa8xkaaaa!440E!\[\widetilde\eta = \eta (T)/\eta (T_c )\] in this approximation is smaller than those in the s-wave and s-p-wave approximations at all temperatures. The numerical result for \~ in the s-p-d- wave approximation is in good agreement with the recent experimental data of Parpia et al. and of Alvesalo et al. in the temperature range 0.5.t1.0.Supported in part by the Nishina Memorial Foundation and in part by the NSF under Grant No. DMR-76-24011.     

Design and synthesis of oligosaccharides that interfere with glycoprotein quality-control systems

Calnexin (CNX) and its soluble homologue calreticulin (CRT) are lectin-like molecular chaperones that help newly synthesized glycoproteins to fold correctly in the rough endoplasmic reticulum (ER). To investigate the mechanism of glycoprotein-quality control, we have synthesized structurally defined high-mannose-type oligosaccharides related to this system. This paper describes the synthesis of the non-natural undecasaccharide 2 and heptasaccharide 16, designed as potential inhibitors of the ER quality-control system. Each possesses the key tetrasaccharide element (Glc1Man3) critical for the CNX/CRT binding, while lacking the pentamannosyl branch required for glucosidase II recognition. These oligosaccharides were evaluated for their ability to bind CRT by isothermal titration calorimetry (ITC). As expected, each of them had a significant affinity towards CRT. In addition, these compounds were shown to be resistant to glucosidase II digestion. Their activities in blocking the chaperone function of CRT were next measured by using malate dehydrogenase (MDH) as a substrate. Their inhibitory effects were shown to correlate well with their CRT-binding affinities, both being critically dependent upon the presence of the terminal glucose (Glc) residue.     

Modeling and scale-up simulation of U-tube ozone oxidation reactor for treating drinking water

In the present study, we developed a novel simulation model of the U-tube reactor for treating drinking water, which is composed of a coaxial inner tube serving as an efficient concurrent down-flow ozone dissolver and an outer column carrying out reactions between ozone and organic substances including odorous materials (2-methylisoborneol: 2-MIB) dissolved in the raw water. We assume that the U-tube is composed of a plug flow section (inner tube) followed by a tanks-in-series section (outer bubble column) and take into account the effect of the hydrostatic pressurization on the flow and absorption equilibrium for the gaseous components including ozone and other inactive species in developing the mass balance models. An algorithm is constructed of the differential multiple mass balance equations for the inner tube sections and multiple difference mass balance equations in the series tanks in the outer column section to enable the scale-up from a pilot plant to a full-scale plant. The gas holdup and gas-liquid mass transfer coefficient were measured in a model reactor and correlated for the use of the simulation calculation. Available literature data and correlations on the rates of reactions between ozone and organic substances including odorous material 2-MIB, gas-liquid equilibrium for active and inactive gases and axial fluid mixing properties are also incorporated in the simulation calculation. The simulation results well explained the available data of the ozone absorption efficiency and the removal efficiency of the odorous material in a pilot U-tube reactor. The simulation procedure was also successfully extended to verify the performance of a full-scale U-tube reactor. It is shown that the ozone absorption is practically a single function of the gas/liquid ratio while the removal efficiency of the odorous material is a single function of the ozone dose for a specified U-tube configuration.     

Kinetics of the hydrogenation of fatty oils

Hydrogenation results for fatty oils were analyzed by using a nonlinear least squares method. The rate of the hydrogenation for diunsaturated fatty groups to monounsaturated groups and the rate of the geometrical isomerizations between monounsaturated groups were found to be half order with respect to hydrogen concentration, whereas the hydrogenation rate of monounsaturated groups was the first order. A detailed reaction mechanism is presented to explain the kinetic behavior.     

A surface silylated single-layer resist based on limited gas permeation

A simple alternative was studied for the tri-layer resist system. One single thick layer of resist polymer was surface silylated to obtain a bilevel structure that functioned similarly to the bilayer resist composed of the Si-containing top imaging and the bottom planalizing layers. A resist or matrix polymer layer containing phenolic – OH groups was silylated by exposing it to hexamethyldisilazane vapor, and Si atoms were effectively incorporated in the surface sublayer by limited gas permeation and reaction with the – OH groups. Oxygen RIE durability of the silylated poly(vinyl phenol) or the positive-working commercial EB resist, RE-5000P, was > 10 times as high as that of PVP or RE-5000P before silylation. The surface silylated single-layer (SSS) resist derived from RE-5000P was flood-exposed through a mesh mask to 11.7°C/cm² of 4 KeV electrons, developed with tetramethylammonium hydroxide in aqueous methanol, and plasma-developed in an O₂ RIE chamber to form a positive-tone relief image.     

Catalytic hydrogenation of carbon monoxide over silica-supported Ir-Mo-Rh catalyst

We present here some results on Ir-Mo-Rh metallic catalysts for the synthesis of C₂-C₄ alcohols from syngas. It was found that Ir-Mo-Rh supported on silica containing small amounts of Rh exhibited much higher activity for CO hydrogenation than Ir-Mo bimetallic catalyst. The selectivity to various alcohols did not change very much upon the addition of Rh. The activity was greatly affected by the impregnation procedure of the metals in the catalyst preparation.     

Acrylic/polyester hybrid powder coating system having excellent weather durability

There have been many attempts to improve weather durability in polyester powder coatings. However, no effective suggestion improves weather durability without sacrificing other properties, such as mechanical properties. A novel polyester powder coating system is described in this article, with especially excellent weather durability. This system was based on an acrylic/polyester hybrid curing system composed of polyester resin showing excellent weather durability and the new GMA-acrylic hardener which has a ‘soft segment' in its structure. The advanced acrylic/polyester hybrid curing system shows both excellent weather durability and good mechanical properties.     

Residual stress in particulate epoxy resin by X-ray diffraction

Residual stress in particulate epoxy resin was investigated by X-ray diffraction. Microdeformation of incorporated Al and α-SiO₂ crystal, which was induced by the residual stress, could be detected as a shift of X-ray diffraction peak. The residual stress at the interface between the adherend and the particulate epoxy resin was found to decrease with the increase of volume fraction of filler. It was shown that the difference in the thermal expansion coefficients between the adherend and the particulate epoxy resin is much more effective on residual stress than the increment of Young's modulus owing to the incorporation of filler. When epoxy resin was cured on the Al plate, incorporated particles were subjected to a tensile stress; while cured on polytetrafluoroethylene sheet, particles were subjected to a compressive stress. The incorporation of some inorganic particles is considered effective to reduce the residual stress.     

Pressure-dependence of dielectric relaxation time in poly(propylene glycol) and its application to high-pressure viscosity estimation

Dielectric permittivity and loss of poly(propylene glycol) with different molecular weights (400–3000) and terminal groups (OH and CH₃) have been measured in the frequency range of 100 Hz to 1.5 MHz. Measurements were conducted over the temperature range 202–293 K under atmospheric pressure and 283–320 K under pressure up to 600 MPa. Two relaxation processes, one with strong absorption in the high-frequency region (α-relaxation) and the other a weak process in the low-frequency region (α′-relaxation), were observed for the OH-terminated samples having molecular weights above 2000 and for all the CH₃-terminated samples. Most of the experimental data under high pressure showed a nonlinear decrease in the logarithm of the frequency of maximum dielectric loss with increasing pressure. The pressure-dependence of the dielectric relaxation time of the α-process was analyzed by several models based on the free-volume concept. The regression results of dielectric relaxation time as a function of pressure were applied to the estimation of high-pressure viscosity. The predicted viscosity showed relatively good agreement with viscosity data obtained from a falling-sphere viscometer.     

Influence of the applied pressure waveform on the dynamic fracture processes in rock

Dynamic fracture process analyses for different waveforms of borehole pressure are conducted using a proposed numerical simulation method in order to verify the dynamic fracture mechanism related to blast-induced borehole breakdown. The fracture processes are affected more by the rise time increases than by the decay time. A higher stress-loading rate increases the number of radial cracks and leads to intense stress release around running cracks. The stress release caused by adjacent cracks interferes with crack extension and results in shorter crack propagation. At lower stress-loading rates, the number of cracks and the crack arrest caused by the stress released at adjacent cracks are reduced, leading to longer crack extension. These analyses reveal that the earlier preferential crack development occurs the greater the extension of the crack. The dynamic fracture process analyses are extended to investigate the influence of the waveform of applied pressure on the dynamic fracture process in a free face model. These fracture processes reveal that crack extension increases with the rise time increase, and that when the rise time is sufficiently long, crack extension depends, predominantly, on the rise time and the peak value of applied pressure. Crack arrest occurs after the peak phase of the stress wave in all cases. The effects of rock inhomogeneity on fracture pattern are discussed.