Effect of the atomic packing density on the structural change rate of amorphous alloys under elastostatic stress

This study deals with the fundamental issue of whether the atomistic-scale structure of amorphous alloys can be altered by the application of elastic stress. The prolonged imposition of elastostatic stress on amorphous alloys induces permanent structural change. The rate of change largely depends on the atomic packing density, which is characterized by the fractions of various short-range ordered clusters. This structural change is accompanied by the formation of excess free volume, which in turn affects the mechanical properties in subsequent compression tests. The findings of the experiments and molecular dynamics simulations were analyzed in terms of atomistic-scale structural changes.     

Development on a coaxial heat integrated distillation column (HIDiC)

Various configurations of a column for performing the principle of HIDiC can be proposed, but a coaxial column which is installed a packing in an inside tube and outer side may be one of the simplest columns for HIDiC. In order to examine whether or not the configuration of the packed column mentioned above is appropriate to HIDiC, an experimental apparatus has been set up and heat and mass transfer rates have been measured by using benzene-toluene system. This paper was presented at The 5th International Symposium on Separation Technology-Korea and Japan held at Seoul between August 19 and 21, 1999.     

Dynamic Properties of Highly Organic Soils from Montezuma Slough and Clifton Court

The nonlinear dynamic properties of highly organic soils from two levee sites in the Sacramento-San Joaquin Delta in California are described. Cyclic triaxial, resonant column and torsional shear tests were performed on thin-walled tube samples obtained from beneath levee crests, beneath adjacent berms, and in the free field such that the in situ vertical effective stresses (σvo′) ranged from about 16?to?67?kPa. These highly organic soils had considerably different organic characteristics from those used in previous studies of dynamic properties. The tested samples had organic contents of 14 to 61%, initial water contents (wo) of 88 to 496%, shear wave velocities (Vs) of 20?to?130?m/s, and organic components that ranged from highly fibrous to highly decomposed and amorphous. Secant shear modulus (G), normalized secant shear modulus (G/Gmax), and equivalent damping ratio (ξ) versus cyclic shear strain amplitude (γc) relations are presented, and their dependence on variables such as consolidation stress, organic content, prior loading history, testing device, and loading frequency are illustrated. Findings are compared to previously published results.     

Integration of imitation learning using GAIL and reinforcement learning using task-achievement rewards via probabilistic graphical model

The integration of reinforcement learning (RL) and imitation learning (IL) is an important problem that has long been studied in the field of intelligent robotics. RL optimizes policies to maximize the cumulative reward, whereas IL attempts to extract general knowledge about the trajectories demonstrated by experts, i.e, demonstrators. Because each has its own drawbacks, many methods combining them and compensating for each set of drawbacks have been explored thus far. However, many of these methods are heuristic and do not have a solid theoretical basis. This paper presents a new theory for integrating RL and IL by extending the probabilistic graphical model (PGM) framework for RL, control as inference. We develop a new PGM for RL with multiple types of rewards, called probabilistic graphical model for Markov decision processes with multiple optimality emissions (pMDP-MO). Furthermore, we demonstrate that the integrated learning method of RL and IL can be formulated as a probabilistic inference of policies on pMDP-MO by considering the discriminator in generative adversarial imitation learning (GAIL) as an additional optimality emission. We adapt the GAIL and task-achievement reward to our proposed framework, achieving significantly better performance than policies trained with baseline methods.     

15.1% Highly efficient thin film CdS/CdTe solar cell

High-efficiency CdS/CdTe solar cells with thin CdS film have recently been developed. Semiconductive layers of CdS via the CVD method and of CdTe via the CSS method were deposited on an ITO/#7059 substrate. Cell performance depends primarily on the thickness of CdS film, and the conversion efficiency is highest for a CdS film thickness of around 60 nm. Since the CdS film thickness decreases by about 30% during deposition of the CdTe layer, a thickness of 95 nm is required to obtain a 60 nm-thick CdS film after deposition of a CdTe layer. By observing the CdS film during the CdTe deposition process, a decrease was detected before CdTe layer completely covers the surface of the CdS film. By optimizing the thickness of CdS film, an efficiency of 15.12% for the best cell under AM 1.5 verified at JQA was obtained. This fabrication process has good reproducibility; 92.5% of 1 cm² solar cells fabricated under the same conditions have efficiencies above 14%.     

Electrochemical supercapacitor behavior of nanoparticulate rutile-type Ru1−xVxO2

Rutile-type Ru_1−xV_xO₂ nanoparticles possessing high surface area were prepared by a polymerizable-complex method and its electrochemical supercapacitor behavior was studied. X-ray diffractometry, energy-dispersive X-ray analysis, and N₂ adsorption/desorption measurements were used to characterize the structure of the products. The electrochemical supercapacitor behavior of thick and thin films was studied by cyclic voltammetry in various acidic, neutral, and alkaline electrolytes. Ru_1−xV_xO₂ exhibited extremely enhanced supercapacitive properties compared to pure RuO₂. The highest surface redox activity was achieved with an acidic electrolyte. Ru_1−xV_xO₂ showed negligible surface redox activity in neutral electrolytes.     

High surface area solids obtained by intercalation of iron oxide pillars in montmorillonite

When montmorillonite is dispersed in aqueous solutions of trinuclear acetato-hydroxo iron(III) nitrate, [Fe₃(OCOCH₃)₇OH]NO₃, the interlayer cations of the montmorillonite are exchanged with the partially hydrolyzed trinuclear acetato complex ions. On heating the exchanged complex ions are converted into iron oxide pillars which keep the silicate layers apart and form micropores between the layers. The resulting product has a basal spacing of 16.7 Å and a specific surface area of about 300 m²/g at 500°C. Adsorption isotherms for various vapors on the product have been measured.     

Site-specific mutagenesis of the N-(deoxyguanosin-8-yl)-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine DNA adduct in mammalian cells

 Site-specifically modified oligodeoxynucleotides were used to explore the mutagenic properties of a cooked food mutagen-derived DNA adduct, N-(deoxyguanosin-8-yl)-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (dG-C8-PhIP). A dG-C8-PhIP-modified oligodeoxynucleotide was prepared post-synthetically by reacting an oligodeoxynucleotide containing a single dG (^5′-TCC TCC TCG CCT CTC T) with N-acetoxy-PhIP. The unmodified and dG-C8-PhIP-modified oligomers were inserted into single-strand (ss) phagemid vectors. These ss vectors were transfected into simian kidney (COS-7) cells. The progeny plasmid obtained was used to transform Escherichia coli DH10B. The transformants were analyzed by oligodeoxynucleotide hybridization and sequencing to determine the mutation frequency and spectrum. Preferential incorporation of dCMP, the correct base, was observed opposite dG-C8-PhIP. Targeted mutants showing G→T transversions were detected, along with a small number of G→A transitions and G→C transversions. Significant amounts of non-targeted mutations representing C→T transitions also were detected 5′ to the dG-C8-PhIP lesion. Thus, dG-C8-PhIP, a major DNA adduct induced by PhIP, is mutagenic in mammalian cells and may be involved in the initiation of human cancer. Received: 23 April 1998     

Voltage and reactive power control using recurrent neural networks

Many controllers using neural networks have been recently developed. The hybrid and direct types are two major categories of such controllers. While the first type tunes the parameters of the conventional controller by means of neural networks, the latter constructs the controller by learning the inverse dynamics of the control target. Electric power systems require voltage and reactive power (VQ) control to avoid voltage collapse. The conventional VQ control, however, meets this requirement unsatisfactorily because the control is only approximate. In this paper, we will propose a new algorithm for VQ control using recurrent neural networks (RNNs), which have the ability to deal with the system's controlled target by means of RNNs. Second, we will apply this algorithm to VQ control. We will call this controller “neuroVQC.” Finally, the usefulness of the neuroVQC will be shown by comparison with the conventional VQ controller.     

An echocardiographic study of interactions between pindolol and epinephrine contained in a local anesthetic solution

An increasing number of dental patients are taking beta-adrenergic blockers for the treatment of hypertension or angina pectoris. If epinephrine-containing local anesthetics are administered to such patients, interactions between epinephrine and the beta-blocking agent may induce cardiovascular complications. We assessed in volunteers the effects of intraoral injection with 2% lidocaine containing 1:80,000 epinephrine (L-E) on cardiac function after pretreatment with the beta-blocking agent pindolol. M-Mode echocardiography was used for the assessment. The injection of L-E after administration of pindolol did not alter cardiac preload, whereas it reduced the stroke volume, due to an increase in afterload and a decrease in myocardial contractility. Reductions in stroke volume and heart rate led to a decrease in cardiac output. Because total peripheral vascular resistance increased markedly, blood pressure was elevated despite the reduced cardiac output. These results suggest that cardiac function of dental patients on beta-blocker therapy can be adversely affected by epinephrine-containing local anesthetics. Therefore, when such an anesthetic solution has to be used in patients on beta-blocker therapy, careful systemic monitoring is needed.