Unique Features of Mobile Commerce

While the market potentials and impacts of web-based e-commerce are still in the ascendant, the advances in wireless technologies and mobile networks have brought about a new business opportunity and research attention, what is termed mobile commerce. Commonly, mobile commerce is considered to be another new application of existing web-based e-commerce onto wireless networks, but as an independent business area, mobile commerce has its own advantages and challenges as opposed to traditional e-commerce applications. This paper focuses on exploring the unique features of mobile commerce as compared with traditional e-commerce. Also, there are still some limitations arisen in m-commerce in contrast to web-based e-commerce. Finally, current state of mobile commerce in Japan is presented in brief, with an introduction of several cases involving mobile commerce applications in today's marketplace.     

DNA ANALYSIS FOR IDENTIFICATION OF FOOD-ASSOCIATED FOREIGN SUBSTANCES

To identify food‐associated foreign substances, a DNA analysis consisting of 18S rDNA sequencing and homology search analysis has been developed. In this method, we designed universal primer pairs for specific amplification of animal and plant 18S rDNA and constructed an original DNA database storing partial 18S rDNA sequences of 222 organisms commonly used for culinary purposes. In the model experiments, food materials were successfully identified, indicating that our DNA analysis method can be practically applied to the identification of food‐associated foreign substances. It is also expected that this method complements conventional morphological and compositional analysis, leading to more accurate and reliable identification of food‐associated foreign substances.     

A SPECIFIC QUALITATIVE DETECTION METHOD FOR PEANUT (ARACHIS HYPOGAEA) IN FOODS USING POLYMERASE CHAIN REACTION

A qualitative method for detection of peanuts in foods using polymerase chain reaction was developed. A universal primer pair CP 03‐5′/CP 03‐3′ was designed to confirm the validity of the DNAs for PCR. The plant‐specific amplified fragments were detected from 13 kinds of plants using the universal primer pair. In addition, for the specific detection of peanuts with high sensitivity, the primer pair agg 04‐5′/agg 05‐3′ was designed to detect the gene encoding the peanut agglutinin precursor. The primer pair specifically generates a 95‐bp amplified fragment from peanut genomic DNA. Five hundred femto grams of peanut genomic DNA can be detected using the established method. The same qualitative results were obtained from both model processed and nonprocessed food samples containing 0.001, 0.01 and 0.1% of peanut. Moreover, it was shown that the trace amount of peanut in the commercial food products could be qualitatively detected using this method. The reproducibility and applicability of the proposed methods were verified in a six‐laboratory collaborative study.     

添加剂对酸性橙7水溶液光褪色的影响

本文研究了添加剂对酸性染料酸性橙７水溶液光褪色的影响．二氨基蒽醌一般能抑制褪色,这是由于二氨基蒽醌对水中生成的单线态氧产生湮灭作用;环糊精抑制褪色,是由于其包接作用使染料的偶氮基团被保护起来;二氧化钛能显著促进光褪色,是由于它的光催化作用．     

DEPENDENCE STRUCTURE— DEPENDENCE AS A BINARY RELATION

In systems theory, we often use the concept of dependence. There are several research to construct a unified framework for dependence. Mainly, the concept of dependence is defined with a dais of subsets, where the concept of algebraic closure systems is often used.

In this paper, we define dependence as a binary relation, which we call dependence structure, and develop a similar argument as for the dependence with a class of subsets. And we will clarify a relationship between dependence structure and the usual concept of dependence.

We also show what conditions assure the existence of a basis for a dependence structure.

The concept of functional dependence in database theory can be represented as a dependence structure and we will show that a key for a relational scheme is a basis for the dependence structure.     

ZrB2陶瓷与Al-Sn-Mg合金扩散焊研究

在大气环境下,采用扩散焊接方法进行了ZrB2陶瓷与A1-Sn-Mg合金的连接.Al-Sn-Mg合金为Al-x%Sn-y%Mg(x=0,0.5,1.0,2.0;γ=0,0.5,1.0,2.O),ZrB2陶瓷为纯ZrB2型.焊接工艺是在1、2和4MPa的压力,873K的温度下保持3.6、7.2和14.41 ks.采用扫描电镜、电子探针及剪切试验等测试方法研究了其接头的组织及力学性能.结果表明,ZrB2陶瓷能够与Al-Sn-Mg合金实现扩散连接."Al-Sn"合金可作为ZrB2陶瓷扩散焊中间层材料使用.最合适的合金为AI-0.5Sn-0.5Mg.ZrB2/Al-0.5Sn-0.5Mg在873K温度下进行扩散焊.焊接压力在2～4MPa,保温时间在7.2～14.4ks时获得的接头强度都在42～44MPa之间,但该接合强度只能保持到373K,不适合在高温环境下使用.     

Meaning of state-space representation and its relation to canonical form Part 2. Controllability and constructibility

State space is one of the key concepts of systems theory. In the previous paper (Nakano et al. 1987) a system-theoretic framework about the choice of a state space was developed and the canonical forms of linear control theory were interpreted. Four realizations of a single-input and single-output discrete basic linear system were constructed. The isomorphism between the realizations and the universal state space representation shows systemic meanings of the state space. In this paper, using the same approach, two other realizations—a controllability realization and a constructibility realization—are constructed. By the matrix representations of these realizations the meanings of the controllability and constructibility canonical forms are shown in relation to the universal state-space representation.     

Ageing behaviour in a dental low-gold alloy with high copper content

Phase transformation behaviour in a dental low-gold alloy with high copper content during continuous heating was investigated by hardness tests, electrical resistivity measurements, X-ray diffraction, scanning and transmission electron microscopies. Two kinds of solution treatment conditions (at 873 K and 1073 K) followed by iced-brine quench, represented different ageing behaviours. Although subsequent anisothermal annealing produced same phase separation of face-centred cubic disordered and ordered (Cu3Au) phases in both specimens, the specimen quenched from 1073 K had already been hardened by a spinodal decomposition. © 1998 Chapman & Hall