Heat capacities of the anomalous fluid phase in two-dimensional 3He

No Heading We measured heat capacities of two dimensional ³He adsorbed on graphite preplated with a ⁴He monolayer (³He/⁴He/gr) in a wide temperature (0.3 T 80 mK) and density range (1.3 7.3 nm^–2). We found that the system behaves as a normal Fermi fluid at low densities between 1.3 and 5.6 nm^–2 where the quasiparticle effective mass seems to diverge at a density for the 4/7 phase (_4/7 = 6.8 nm^–2). At higher densities but below _4/7, we observed anomalous temperature dependencies of heat capacity with two round maxima near 1 and 30 mk. With increasing density in this region, a high temperature weight of heat capacity decreases selectively leaving the 30 mK peak, while the 1 mK peak develops. This unexpected behavior can not be explained by the conventional two-phase co-existence model. Instead, we propose here that the 2D normal Fermi fluid is continuously transformed to the 4/7 Mott localized phase through a new quantum phase where a hopping of the zero-point vacancy plays an important role.PACS numbers: 75.70.Ak, 67.80.Jd, 75.10.Jm, 67.70.+n.     

Assessment of dynamic stability of large-scale power system by Rayleigh's quotient

A method of assessing dynamic stability of large-scale power system by Rayleigh's quotient is proposed. One-machine infinite-bus systems show damping torque characteristics similar to diagonal components of operational transfer matrices for original multimachine systems, which means that design of PSS with one-machine systems controls those components. An expression for damping constants of oscillation modes is derived based on an energy function and its time derivative for a simplified system representation. This expression demonstrates that oscillations do not necessarily become unstable even if there are some generators with negative damping; and the effect of damping torque is determined by eigenvectors. The expression is generalized with Rayleigh's quotient, and a method of estimating eigenvalues of large-scale power systems is proposed. With this method, approximate eigenvalues are refined to accurate eigenvalues. Only a specified number of eigenvalue analyses are required irrespective of the number of generators, hence much calculation is saved. Finally, this method is applied to a 107-machine system to verify its effectiveness.     

Determination of gibbs energy of formation of cuspidine (3CaO · 2SiO<Subscript>2</Subscript> · CaF<Subscript>2</Subscript>) from the electromotive force method using CaF<Subscript>2</Subscript> as the solid electrolyte

The standard Gibbs energy change for the following reaction has been directly determined by electromotive force (EMF) measurement using CaF₂ as the solid electrolyte in the temperature range from 1313 to 1329 K.

Optimization of growth of peptide chain by ribosomes on messenger RNA

To elucidate the integrated functional properties and organization strategy of the peptide elongation process of ribosomes on messenger RNA, we took a theoretical approach by applying a linear system analysis and optimal hypothesis. The basic theoretical model published by Gerst in 1965 was founded on reported experimental data. We have simplified the mechanism of the peptide elongation process by making the following assumptions. (1) When the left-most site (the 5′ terminal) on the messenger RNA is empty, the newly arrived amino-acyl-transfer-RNA (AT) links to the 5′ terminal even though other sites are empty. (2) When all other sites on the ribosomes except the 5′ terminal are empty and the first ribosome is not yet filled, ATs which arrive subsequently continue to bind to the 5′ terminal site of the first ribosome until the first ribosome has been filled. (3) When a given ribosome has been filled by an amount of product equivalent to the product ofp (amino acid residues) andq ribosomes, the filled ribosome advances to the next ribosomal region (q+1). There, the amino acid attainspq+1. After this transition, theqth ribosomal region becomes empty. (4) When the sites on the ribosomes are not all filled, newly arrived AT binds from the right of the total sequence. By applying the mass action law, the elongation process was expressed by 23 rate equations. The rate constants for the binding ribosome, turn over, peptide bond formation and transitional movement of ribosomes were utilized from reported experimental data. The optimal state was defined when the square of the concentration of all the transitional states and control input were minimized. This means that the elongation process is in the most economical state when there are no excessive changes at any steps of the elongation process and the least energy consumption. Linear system analysis showed that system was stable and controllable. The singular value was depressed by system optimization. The impulse response terminated earlier by a smaller peak amplitude in the optimized system than in those without optimization. The present model under optimal control is available to evaluate the functions of peptide synthesis on a messenger RNA, and to produce artificial protein from the standpoint of system optimization.     

Prediction of permeability changes in an excavation response zone

In geologic disposal of radioactive wastes, stress changes due to cavern excavation may expand the existing fractures and create possible bypasses for groundwater. This paper proposes a simple method for predicting permeability changes in the excavation response zones. Numerical analyses using this method predict that the response zones created by cavern excavation would differ greatly in thickness and permeability depending on the depth of the cavern site and the initial in-situ stress, that when the cavern site is deeper, response zones would expand more and permeability would increases more, and that if the ratio of horizontal to vertical in-situ stress is small, extensive permeable zones at the crown and the bottom would occur, whereas if the ratio is large, extensive permeable zones would occur in the side walls.     

A case of intractable temporal lobe epilepsy: discrepancy between epileptogenic area and structural lesion demonstrated by subdural recording

We reported a 25-year-old man with intractable right temporal lobe epilepsy in whom subdural recording successfully delineated the epileptogenic area in the right anterior mesial to basal temporal region in spite of the presence of a postoperative lesion in the right posterior temporal region. The patient underwent right posterior temporal resection due to ependymoma at the age of 8 years. Since age 19, he had suffered from medically intractable psychomotor seizures. Ictal scalp-recorded EEG suggested an epileptogenic area at the right temporal area, but it could not specifically demarcate the site because of bone deficits from the previous surgery. Ictal SPECT showed a hyperactive area in the right anterior temporal area, which was inconsistent with the MRI finding. In case of partial epilepsy associated with structural lesion like in the present case, if results of various non-invasive studies are discrepant as to the epileptogenic area, invasive studies using, for example, subdural EEG monitoring is necessary to determine the responsible area.     

Video-assisted thoracoscopic surgery of bullous and bleb disorders of the lung using endoscopic stapling device

The video-assisted thoracic surgical (VATS) approach appears to be a viable alternative to thoracotomy when surgical management of bullous and bleb disorders of the lung is required. Fifty patients with giant bullae (n = 6) and spontaneous pneumothoraces (n = 44) were recently treated by our group using the VATS approach and endoscopic stapling devices. Of the 50 patients, 47 were managed completely by the VATS approach, including six giant bullae that were asymptomatic in five and infectious in one and 41 pneumothoraces, of which 16 were first episode and 25 with recurrent pneumothorax. Median operating times for the bullous and bleb excisions were 147.8 and 45.9 min, respectively (p < 0.01), and median chest tube durations were 5.2 and 1.2 days, respectively (p < 0.05). There was no mortality, and significant morbidity was limited to prolonged air leak in more than 5 days in three patients and postoperative atelectasis in two patients. Median hospital stays of patients with bullous excision was 11.3 days compared with 4.7 days of those with bleb excision. We conclude that the VATS treatment is a safe, effective procedure in patients with bullous and bleb disorders of the lung even in asymptomatic giant bullae or spontaneous pneumothoraces with the first episode. The advantages of the VATS approach for these diseases are ease of operation, less pain, early mobility, and superior cosmetic results.     

Inspection policy with failure due to inspection

In this paper, we discuss the inspection policy for the modified inspection model taking account of the system failure due to any inspection. We obtain the nearly optimal inspection policy which minimizes the nearly total expected cost up to the detection of the system failure. We also present the numerical examples of the nearly optimal inspection policy by assuming a Weibull distribution for illustration.     

Surface properties and catalytic activities of amorphous niobium phosphate and a comparison with those of H3PO4-treated niobium oxide

Amorphous niobium phosphate was prepared by addition of phosphoric acid to an aqueous solution of potassium niobate. The surface property of the amorphous phosphate was highly dependent on degrees of aging of the precipitate and ranoval of K⁺ contaminant. As well as the phosphoric acid-treated Nb₂O₅) the amorphous phosphate was active as a catalyst for some acid-catalyzed reactions such as MTBE synthesis, esterifications using acetic acid, and alkylations of benzene.