We have designed new trithiols Temp(SH)(3) and Tefp(SH)(3) that can be synthesized conveniently in short steps and are useful for preparation of crystalline [3:1] site-differentiated [4Fe-4S] clusters suitable for X-ray structural analysis. The ethanethiolate clusters (PPh(4))(2)[Fe(4)S(4)(SEt)(TempS(3))] (4a) and (PPh(4))(2)[Fe(4)S(4)(SEt)(TefpS(3))] (4b) were prepared as precursors, and the unique iron sites were then selectively substituted. Upon reaction with H(2)S, (PPh(4))(2)[Fe(4)S(4)(SH)(TempS(3))] (6a) and (PPh(4))(2)[Fe(4)S(4)(SH)(TefpS(3))] (6b), which model the [4Fe-4S] cluster in the β subunit of (R)-2-hydroxyisocaproyl-CoA dehydratase, were synthesized. Clusters 6a and 6b were further converted to the sulfido-bridged double cubanes (PPh(4))(4)[{Fe(4)S(4)(TempS(3))}(2)(μ(2)-S)] (7a) and (PPh(4))(4)[{Fe(4)S(4)(TefpS(3))}(2)(μ(2)-S)] (7b), respectively, via intermolecular condensation with the release of H(2)S. Conversely, addition of H(2)S to 7a,b afforded the hydrosulfide clusters 6a,b. The molecular structures of the clusters reported herein were elucidated by X-ray crystallographic analysis. Their redox properties were investigated by cyclic voltammetry.

This study was designed to investigate relations among autonomy, self-referenced beliefs, and self-regulated learning for 356 elementary school children (180 boys and 176 girls) from Grades 5 and 6. They were asked to complete a questionnaire designed to measure four types of motivation, self-esteem, strategy beliefs, capacity beliefs, control beliefs, and values, three types of goal orientations, and three types of learning strategies. Four types of motivation (external, introjected, identified, and intrinsic regulations) were shown to conform to a simplex structure or ordered correlational structure. Correlations among scores on autonomy (four kinds of regulation) and on self-regulated learning and between scores on self-referenced beliefs and on self-regulated learning were examined. Finally, canonical correlation was used to investigate the relations between autonomy and learning and between beliefs and learning. Implications of the findings for the relations were discussed.

The purpose of the present study was to examine the influence of goal orientations on ninth-grade students' (54 girls and 55 boys) task-specific appraisals (i.e., anticipated interest, self-efficacy, test anxiety, and physical symptoms) and subsequent task performance. The results of structural equation modeling showed that different goal orientations had different effects on task-specific appraisals. In addition, task performance was directly influenced by self-efficacy and physical symptoms, whereas the goal orientation served as a predictor of task performance indirectly through task-specific appraisals. Students' posttask estimation of success and involvement were differently predicted by the pretask appraisal and actual task performance. Thus self-appraisals that students experience after performing the task are not only influenced by the actual performance, but also by the task-related appraisal they form before the task, which is partially determined by their goal orientations. Cluster analysis revealed students with multiple goals, in whom learning and performance goals can work together to facilitate performance and motivation.Key words : goal-orientation, task interest, self-efficacy, test anxiety, physical symptoms.Although generalized motivational orientations such as the goal orientation are important to the way students construe a situation, action-related plans and their intended and actual implementation are more dependent on situation-specific appraisals (Niemivirta, 1999(Niemivirta, , 2002. The behavior of a student who perceives school task and performance situations as meaningful personal challenges still varies according to his or her task-specific perceptions about, for example, task difficulty, available knowledge, self-efficacy, and interest. In other words, the influence of enduring and generalized self-related beliefs on performance is mediated through task-specific appraisals, which, in turn, are likely to bear an additional independent effect on the actualized engagement.However, there are few studies that emphasize the conceptualization of different levels of abstraction. The present study concentrates on two levels of abstraction. The first concerns students' enduring and generalized motivational orientations, and the second focuses strictly on situational and task-related perceptions. Generalized motivational orientationsWithin the research on students' achievement motivation, achievement goal theory has been advanced to identify two contrasting primary types of goal orientations. Different labels are used to characterize these two types of goal 1 The author acknowledges the valuable cooperation of Prof. Markku Niemivirta (University of Helsinki), and the useful comments of Prof. Hirotsugu Yamauchi (Doshisha University) and of Prof. Shizuhiko Nishisato (University of Toronto). Thanks are also due to Chiemi Kan who helped to collect data, and the students and the teachers who participated in the research project.

The purpose of this study is to investigate a nondestructive method for predicting the fatigue limit of spheroidal graphite cast iron using high resolution X-ray CT. Axial load fatigue test specimens were cut out from a large spheroidal graphite cast iron equivalent to FCD 350, and graphite and defects in the material were detected using high resolution X-ray CT for all specimens. Fatigue limit was estimated from the graphite and defect sizes using the fatigue limit estimation formula based on the four-parameter method.Axial load fatigue test was performed in accordance with JIS (Japanese Industrial Standards). Repetition frequency was 17 Hz, stress ratio was R = ¹1, and number of cycles during the test was 1.0 © 10 7 . The specimen used was JIS type 1 of 8.00 mm in diameter. Fracture origins were observed in all fatigue fracture surfaces using a scanning electron microscope (SEM) in order to compare the results between the defects observed by X-ray CT and the fracture origins observed in the fatigue test.The fatigue limit estimated by the defect with the largest volume detected by X-ray CT was 5% lower than the experimental fatigue limit of 125 MPa, which is considered safe estimation. However, in the fatigue test, the fracture origin was not necessarily the defect with the largest volume. Therefore, the fatigue limit was estimated by the average defect size when the cumulative distribution function of ten defects with the largest volume of each test piece was F = 50%. The result was 11% larger than the experimental fatigue limit, which is considered a dangerous estimation. These results indicate that estimation of fatigue limit using a nondestructive method is feasible.

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