Photochemically Switchable Interconnected Microcavities for All-Organic Optical Logic Gate

Optical microcavities confine molecular luminescence and transfer it to a far longer distance than the conventional Förster resonant energy transfer process. Such cavity-mediated energy transfer is advantageous for use in optical circuitry. However, to realize all-organic optical circuits, optical gate operation with organic materials is indispensable. Here, all-organic optical gates consisting of polymer whispering gallery mode (WGM) resonators that work as the optical source, drain, and gate, which are interconnected with polymer microfiber, are demonstrated. Photoirradiation of the source sphere, as an optical input, triggers the blue fluorescence that transmits to the gate sphere through the fiber. The fiber interconnection enhances both the light confinement efficiency in the individual spheres and the light transmission efficiency between distant spheres. The gate sphere contains photoisomerizable fluorescent dye that converts, in its closed state, the blue emission into green light, which is again transmitted to the drain sphere through the fiber and lets the sphere emit red light as an output. This optical cascade is switched on and off upon photoisomerization of the dye in the gate sphere. Furthermore, an energy cascade equipped with two gate spheres works as an OR-type logic gate, demonstrating potential utility for the future all-organic and all-optical integrated devices.     

Kyushu Decorative Tumuli Project: From e-Heritage to Cyber-Archaeology

Digitization of cultural assets has become an important sub-area of computer vision (CV). Thus far, the value of digitization has been emphasized in terms of asset preservation and exhibition. The third aspect of digitization value is that the obtained digital data can be used to perform archaeological analysis based on physics and optics theories and simulations. This position paper emphasizes the importance of this third aspect, using our Kyushu decorative tumuli project as an illustrative example. In particular, we focus on the photometric approaches in the third aspect and explain the equipment and methods developed there as well as archaeological findings. This paper, then, proposes to establish this area as “cyber-archaeology” through categorizing and organizing those methodologies.

     

Exponential family tensor factorization: an online extension and applications

In this paper, we propose a new probabilistic model of heterogeneously attributed multi-dimensional arrays. The model can manage heterogeneity by employing individual exponential family distributions for each attribute of the tensor array. Entries of the tensor are connected by latent variables and share information across the different attributes through the latent variables. The assumption of heterogeneity makes a Bayesian inference intractable, and we cast the EM algorithm approximated by the Laplace method and Gaussian process. We also extended the proposal algorithm for online learning. We apply our method to missing-values prediction and anomaly detection problems and show that our method outperforms conventional approaches that do not consider heterogeneity.     

Effect of molybdenum disulphide upon the friction and wear in ceramic–steel pair

Friction and wear tests between a stationary block and a rotating ring under lubrication with molybdenum disulphide (MoS₂) were carried out at room temperature at a sliding distance of 500 m. Silicon nitride and cemented carbide blocks were pressed against a bearing steel ring, silicon nitride-bearing steel and cemented carbide-bearing steel pairs, by a load of 1600 N. The effect of molybdenum disulphide upon the coefficient of friction and the wear of the steel ring was discussed for both pairs in comparison with mineral oil lubricants. Molybdenum disulphide was more effective in reducing the coefficient of friction and the wear of the ring than the oil lubricants. Various mechanical pretreatment for forming MoS₂ film on the ring surface prior to the sliding tests were also considered. The mechanical pretreatment enabled the sliding test with the low friction coefficient even without lubrication over the sliding distance of 500 m. In general, the coefficient of friction and wear loss of the steel ring were smaller in the silicon nitride-bearing steel pair than in the cemented carbide-bearing steel pair.     

Friction and wear in silicon nitride-steel and cemented carbide-steel pairs in lubricated sliding

Friction and wear tests between a stationary block and a rotating ring under high contact pressure of about 200 MPa were carried out at room temperature under lubrication with a light mineral oil at a sliding distance of 500 m. The block was silicon nitride and cemented carbide, and the ring was bearing steel. The effect of phosphorus and sulphur contained in the mineral oil on the friction, the roughness of the worn surface and the wear of the steel ring is discussed in relation to both pairs. Sulphur was effective in reducing the coefficient of friction of the cemented carbide block-steel ring pair, while phosphorus was successful in decreasing the wear of the steel ring paired with the silicon nitride block. The surface analysis of the steel ring using X-ray photoelectron spectroscopy (XPS) shows that the peak intensities of sulphur or phosphorus beneath the surface depend upon the material of the counterpart, silicon nitride or cemented carbide blocks.     

用超细CBN磨料磨削超耐热合金

本文描述了用新开发的超细多晶CBN磨料成型缓进给磨削镍基超耐热合金的磨削特点。用新型聚晶CBN(CBN—U)磨粒和一种有代表性的传统单晶CBN(CBN—B1)磨粒以缓进给方法一次在平面上磨出一个矩型槽进行了试验。用CBN—U磨料与用CBN—B1相比，磨削力降低了20—30％。用CBN—U磨料进行磨削时，径向和轮廓磨损都较小，磨削比要比CBN—B1磨粒高约4倍。CBN—U磨料在磨削过程中的微破碎尺寸比CBN—B1磨料小。用CBN—U比用CBN—B1砂轮磨损率低而寿命长。     

Inverter-driven synchronous motors for constant power

Inverter-driven synchronous motors are widely used in high-performance variable-speed drive systems. In this article, the effects of machine parameters and the operating characteristics with respect to several types of synchronous motors-which include synchronous reluctance motors, surface permanent magnet synchronous motors, and interior permanent magnet synchronous motors-are examined. The optimum current vector producing the maximum output power at any speed is derived considering both current and voltage constraints     

A Multimicroprocessor-Based Fully Digital AC Drive System for Rolling Mills

Theoretical considerations are given for a control scheme to decrease voltage disturbances in a cycloconverter-fed ac drive system, using a form of the vector control concept. The theory has been applied to a multimicroprocessor-based fully digital 72-arm cycloconverter-fed 5000-kW squirrel-cage induction motor drive control system. For speed and position sensors, a high-resolution sine encoder which generates a 15 000-sine wave/r has been developed to achieve high-performance speed regulation, particularly at ultra-low speeds. The factory test results compare far more favorably than those attainable using dc drives. They reveal that the ac drive system is suited to practical applications in main drives for rolling mills, including tandem cold mills.     

Evolutionary acquisition of behavior to build structural objects by virtual creatures

One of our purposes is to develop virtual creatures which can acquire behaviors such as building structural objects in a 3D physical simulation. In this article, we show the influences of behavior on structural objects which are built by virtual creatures. Many creatures can change their environment for the better by building structural objects, for example, spiders’ nests. In the field of artificial life, there are many studies of virtual creatures which change their bodies and behavior to suit their environments. In contrast, there are few studies about virtual creatures which build structural objects. As for natural creatures, virtual creatures need a physical interaction between their body and their environment. Therefore, our purpose is to develop a framework for the autonomous acquisition of behaviors which build structural objects in a 3D physical simulation. In order to do this, we first studied the evolutionary acquisition of behavior for building structural objects, e.g., a nest for predation, by the simple behavior of throwing blocks. As a result, we show the possibility that virtual creatures can acquire building behavior evolutionarily.     

Computational Reconstruction of Cognitive Music Theory

In order to obtain a computer-tractable model of music, we first discuss what conditions the music theory should satisfy from the various viewpoints of artificial intelligence and/or other computational notions. Then, we look back on the history of cognitive theory of music, i.e., various attempts to represent our mental understandings and to show music structures. Among which, we especially pay attention to the Generative Theory of Tonal Music (GTTM) by Lehrdahl and Jackendoff, as the most promising candidate of cognitive/computational theory of music. We briefly overview the theory as well as its inherent problems, including the ambiguity of its preference rules. By our recent efforts, we have solved this ambiguity problem by assigning parametrized weights, and thus we could implement an automatic tree analyzer. After we introduce the system architecture, we show our application systems.