Shaped silicon-crystal wafers obtained by plastic deformation and their application to silicon-crystal lenses.

Plastic deformation is an unlikely process by which to mould pristine silicon wafers into three-dimensional shapes owing to the inevitable detrimental impact that the resulting mechanically induced defects would have on their electrical properties. However, if one were to find a way of doing so without substantial degradation of these properties, a range of new applications might be opened up. Here we report on the successful plastic deformation of silicon crystal wafers for the preparation of wafers with various shapes. A silicon wafer was set between dies and pressed at high temperatures. One application of shaped wafers is as well-shaped concave silicon crystal lenses or mirrors. The lattice plane of such a crystal lens has a curvature exactly along the surface. A concave spheroidal X-ray lens, in the form of two-dimensional Johann and Johansson's monochromators, is proposed for an X-ray optical component system. We propose and demonstrate a new solar cell system with the concave silicon crystal mirror used as both a solar cell and a focused mirror. This system can make use of the reflected photons from solar cells.     

Three dimensional virtual crack closure-integral method (VCCM) with skewed and non-symmetric mesh arrangement at the crack front

In this paper, an extension of virtual crack closure-integral method (VCCM) for three dimensional linear fracture mechanics analysis using hexahedron finite elements is presented. In conventional three dimensional VCCM, there are some inherent requirements on the finite element model. They are (i) the faces of finite elements across the crack front have the same areas and (ii) they must be arranged symmetrically across the crack front. In present study, we developed a three dimensional VCCM without such requirements by considering work required to open one element face area whose shape is arbitrary. Though we assume the use of an ordinary 20 node serendipity element, present approach can be applied to other types of hexahedron elements.     

Complete Mining of Frequent Patterns from Graphs: Mining Graph Data

Basket Analysis, which is a standard method for data mining, derives frequent itemsets from database. However, its mining ability is limited to transaction data consisting of items. In reality, there are many applications where data are described in a more structural way, e.g. chemical compounds and Web browsing history. There are a few approaches that can discover characteristic patterns from graph-structured data in the field of machine learning. However, almost all of them are not suitable for such applications that require a complete search for all frequent subgraph patterns in the data. In this paper, we propose a novel principle and its algorithm that derive the characteristic patterns which frequently appear in graph-structured data. Our algorithm can derive all frequent induced subgraphs from both directed and undirected graph structured data having loops (including self-loops) with labeled or unlabeled nodes and links. Its performance is evaluated through the applications to Web browsing pattern analysis and chemical carcinogenesis analysis.     

A Knowledge Discovery System with Support for Model Selection and Visualization

The process of knowledge discovery in databases consists of several steps that are iterative and interactive. In each application, to go through this process the user has to exploit different algorithms and their settings that usually yield multiple models. Model selection, that is, the selection of appropriate models or algorithms to achieve such models, requires meta-knowledge of algorithm/model and model performance metrics. Therefore, model selection is usually a difficult task for the user. We believe that simplifying the process of model selection for the user is crucial to the success of real-life knowledge discovery activities. As opposed to most related work that aims to automate model selection, in our view model selection is a semiautomatic process, requiring an effective collaboration between the user and the discovery system. For such a collaboration, our solution is to give the user the ability to try various alternatives and to compare competing models quantitatively by performance metrics, and qualitatively by effective visualization. This paper presents our research on model selection and visualization in the development of a knowledge discovery system called D2MS. The paper addresses the motivation of model selection in knowledge discovery and related work, gives an overview of D2MS, and describes its solution to model selection and visualization. It then presents the usefulness of D2MS model selection in two case studies of discovering medical knowledge in hospital data—on meningitis and stomach cancer—using three data mining methods of decision trees, conceptual clustering, and rule induction.     

双束强辐照对氧化物弥散强化铁素体型合金强化相稳定性影响

采用双束复合辐照装置,研究了He存在条件下,强辐照对长期时效后的ODS合金中强化相(Y2O3)的稳定性和辐照损伤特征的影响。实验结果表明:双束强辐照下,ODS合金中强化相不稳定,发生聚集长大并造成附近基体中Ti、Y浓度增高,导致空洞尺寸和空洞肿胀增加,并对这一结果从理论上进行解释。     

Human-like natural behavior generation based on involuntary motions for humanoid robots

Human behaviors consist of both voluntary and involuntary motions. Almost all behaviors of task-oriented robots, however, consist solely of voluntary motions. Involuntary motions are important for generating natural motions like those of humans. Thus, we propose a natural behavior generation method for humanoid robots that is a hybrid generation between voluntary and involuntary motions. The key idea of our method is to control robots with a hybrid controller that combines the functions of a communication behavior controller and body balancing controllers. We also develop a wheeled inverted pendulum type of humanoid robot, named “Robovie-III”, in order to generate involuntary motions like oscillation. By applying our method to this robot and conducting preliminary experiments, we verify its validity. Experimental results show that the robot generates both voluntary and involuntary motions.     

Preparation and Property of Acrylic Acid Rare Earth Complex and Its Hydrosilylation

Acrylic acid rare earth complex was prepared. Its chemical composition was determined by chemical and elemental analysis, and its structure as well as properties was characterized using IR, Fluorescence and UV spectrum, and its solubility was also investigated. Meanwhile a kind of elastic functional polymer with rare earth units in the side chains was produced. It is confirmed by IR spectrum that the Si-H bonds really react with acrylic acid rare earth.     

Ultra-high voltage electron microscopy: Past,present, and future

High voltage electron microscopy has shown numerous advantages for the study of natural science, including biology, but it is especially useful in materials science. The most important advantage for materials science is in-situ experiments on detailed processes of the same phenomena that occur in bulk materials. For such in-situ experiments, the specimens should be thicker than a few microns to observe the behavior of lattice effect. The maximum observable thickness of the specimens and other advantages markedly increase with increasing accelerating voltage, and since 1965, two 3 MV instruments have been installed. The present paper is mainly concerned with these 3 MV electron microscopes and their applications to new research fields.     

A Technique to Eliminate Redundant Inter-Processor Communication on Parallelizing Compiler TINPAR

Optimizing inter-processor (PE) communication is crucial for parallelizing compilers for message-passing parallel machines to achieve high performance. In this paper, we propose a technique to eliminate redundant inter-PE messages. This technique utilizes data-flow analysis to find a definition point that corresponds to a use point where the definition and the use occur in different PEs. If several read accesses occurred in the same PE use the data defined at the same definition point in another PE, redundant inter-PE messages are eliminated as follows: only one inter-PE communication is performed for the earliest read access and the previously received data are used for the following read. In order to guarantee the consistency of the data, a valid flag and a sent flag are provided for each chunk of received data. The control of these flags is equivalent to the coherence control by the self invalidation on a compiler aided cache coherence scheme.