Early-stage sintering in a powder compact of polyhedral particles II. Experimental analysis with a highly sinterable Al2O3

A model of early-stage sintering for polyhedral particles is examined with a highly sinterable Al₂O₃ powder. Combining of the initial and intermediate stages based on the model concerned describes quantitatively its sintering data such as power dependence of time and reduction in a specific surface area. Valid estimations of a model and/or mechanisms of sintering necessitate the accurate measurement of both shrinkage versus sintering time and specific surface area versus shrinkage.     

Undecidability in the Imitation Game

This paper considers undecidability in the imitation game, the so-called Turing Test. In the Turing Test, a human, a machine, and an interrogator are the players of the game. In our model of the Turing Test, the machine and the interrogator are formalized as Turing machines, allowing us to derive several impossibility results concerning the capabilities of the interrogator. The key issue is that the validity of the Turing test is not attributed to the capability of human or machine, but rather to the capability of the interrogator. In particular, it is shown that no Turing machine can be a perfect interrogator. We also discuss meta-imitation game and imitation game with analog interfaces where both the imitator and the interrogator are mimicked by continuous dynamical systems.     

Development of Radiation Hard ${rm N}^{+}$-on-P Silicon Microstrip Sensors for Super LHC

Radiation tolerance up to 10¹⁵ 1-MeV n_eq/cm² is required for the silicon microstrip sensors to be operated at the Super LHC experiment. As a candidate for such sensors, we are investigating non-inverting n⁺-on-p sensors. We manufactured sample sensors of 1 times 1 cm in 4" and 6" processes with implementing different interstrip electrical isolation structures. Industrial high resistive p-type wafers from FZ and MCZ growth are tested. They are different in crystal orientations lang100rang and lang111rang with different wafer resistivities. The sensors were irradiated with 70-MeV protons and characterized in views of the leakage current increase, noise figures, electrical strip isolation, full depletion voltage evolution, and charge collection efficiency.     

Effect of temperature variation on plastic behavior of S25C mild steel

Plastic behavior of S25C mild steel was investigated at constant and variable temperatures in the range from room temperature to 400°C. The combined loading tests were carried out with the thin walled tubular specimens by applying the axial and torsional loads. The initial yield condition of the material obeyed Tresca's law, but the stress-strain relation after yielding followed neither Tresca's nor Mises's laws. Bauschinger's curves in the torsional loading conditions were different from those in the axial loading conditions. The stress-strain relations subsequent to the tensile pre-strain were obtained at various temperatures. The experimental results were compared with the isothermal stress-strain relation.     

Propagation factors controlling mean field strength on urban streets

Calculation of mean field strength for urban mobile radio has been made on a ray-theoretical basis assuming an ideal city structure with uniform building heights. The result shows that building height, street width, and street orientation as well as mobile station antenna height are controlling propagation parameters in addition to the ordinary factors. The major theoretical characteristics agree approximately with experimental data including conventional empirical predictions. This suggests a way of theoretically predicting mean field strength in an urban area.     

Purification and characterization of the human interleukin-18 receptor

Interleukin (IL)-18 was identified as a molecule that induces IFN-gamma production and enhances NK cell cytotoxicity. In this paper, we report upon the purification and characterization of human IL-18 receptor (hIL-18R). We selected the Hodgkin's disease cell line, L428, as the most strongly hIL-18R-expressing cell line based on the results of binding assays. This binding was inhibited by IL-18 but not by IL-1beta. The dissociation constant (Kd) of 125I-IL-18 binding to L428 cells was about 18.5 nM, with 18,000 binding sites/cell. After immunizing mice with L428 cells and cloning, a single monoclonal antibody (mAb) against hIL-18R was obtained (mAb 117-10C). Sequentially, hIL-18R was purified from 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS)-extracted L428 cells by wheat germ lectin-Sepharose 4B chromatography and mAb 117-10C-Sepharose chromatography. The internal amino acid sequences of hIL-18R all matched those of human IL-1 receptor-related protein (IL-1Rrp), the ligand of which was unknown to date. When expressed in COS-1 cells, the cDNA of IL-1Rrp conferred IL-18 binding properties on the cells and the capacity for signal transduction. From these results, we conclude that a functional IL-18 receptor component is IL-1Rrp.     

Drastic improvement of bioethanol recovery using a pervaporation separation technique employing a silicone rubber‐coated silicalite membrane

A coupled fermentation/pervaporation process for reliable production of concentrated ethanol was studied using ethanol permselective silicalite membranes coated with two types of silicone rubber, KE‐45 and KE‐108, as a hydrophobic material. Ethanol recovery was greatly improved by using a membrane coated with KE‐45 silicone rubber. The recovered ethanol concentration in the permeate was 67% (w/w), and the amount of recovered ethanol from the broth was more than 10 times higher than that using a non‐coated membrane. Succinic acid and glycerol, by‐products created during fermentation, interfered with the pervaporation performance of the coated membrane when used to separate an ethanol/water solution. Copyright © 2003 Society of Chemical Industry     

Frequency stabilization of laser diodes using 1.51-1.55 μmabsorption lines of 12C2H2 and 13C2

Frequency stabilization of a 1.55 μm DFB laser diode is demonstrated using vibrational-rotational absorption of ¹²C ₂H₂ and ¹³C₂H₂ molecules (named VRAM). Frequency stability within 2 MHz peak to peak fluctuation can be achieved in the wavelength region of 1.51-1.55 μm. Frequency-stabilized DFB laser compact modules have been constructed. Frequency stabilities are evaluated by measuring the beat spectrum of the two lasers. In addition, the temperature and pressure dependences of the acetylene absorption lines are characterized     

Experience-dependent effects of cocaine self-administration/conditioning on prefrontal and accumbens dopamine responses.

Experiments were performed to examine the effects of cocaine self-administration and conditioning experience on operant behavior, locomotor activity, and nucleus accumbens (NAcc) and prefrontal cortex (PFC) dopamine (DA) responses. Sensory cues were paired with alternating cocaine and nonreinforcement during 12 (limited training) or 40 (long-term training) daily operant sessions. After limited training, NAcc DA responses to cocaine were significantly enhanced in the presence of cocaine-associated cues compared with nonreward cues and significantly depressed after cocaine-paired cues accompanied a nonreinforced lever response. PFC DA levels were generally nonresponsive to cues after the same training duration. However, after long-term training, cocaine-associated cues increased the magnitude of cocaine-stimulated PFC DA levels significantly over levels observed with nonreinforcement cues. Conversely, conditioned cues no longer influenced NAcc DA levels after long-term training. In addition, cocaine-stimulated locomotor activity was enhanced by cocaine-paired cues after long-term, but not after limited, training. Findings demonstrate that cue-induced cocaine expectation exerts a significant impact on dopaminergic and behavioral systems, progressing from mesolimbic to mesocortical regions and from latent to patent behaviors as cocaine and associative experiences escalate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of Adsorption Potential on 3He Fluid States Formed on 4He-Preplated Substrates

No Heading From heat capacity measurements for ³He adsorbed on ⁴He-preplated mesopore in substrates, FSM-16, HMM-2, and Hectorite, we found fluid states of the ³He adatoms. At very dilute ³He densities, however, it strongly depends on the substrate whether the adatoms are in a localized or a fluid state. The molar heat capacity of a two-dimensional gas or a degenerate Fermi fluid appears above densities n_c = 0, 0, and 2 mol/m² for FSM-16, HMM-2, and Hectorite, respectively. The critical coverages n_c are extremely small or zero for the former two SiO₂-based substrates. On the other hand, n_c for Hectorite is large. Since Hectorite has strong adsorption sites due to the electric-dipole field gradients around ions located on the substrate surface, these potentials are likely to affect the localization of the dilute ³He adsorbed even on the ⁴He film.PACS numbers: 67.55.Cx, 67.70+n, 71.30+h