The ceric salt‐initiated polymerization on acrylamide and graft copolymerization of acrylamide onto cellulose were studied. The mechanism of the ceric salt‐initiated polymerization of acrylamide in the homopolymerization system can be explained by a radical mechanism based upon Ce4+‐coordinated acrylamide, and the mechanism of the ceric salt‐initiated graft copolymerization of acrylamide onto cellulose can be explained in two ways: a free‐radical mechanism with the ceric—cerous redox system, and a radical mechanism based upon Ce4+‐coordinated acrylamide. The velocities of initiation, propagation, and termination in the redox mechanism are quite different from those in the coordinated radical mechanism. From the infrared absorption and nuclear magnetic resonance spectra measurements it is concluded that the structure of the ceric‐coordinated acrylamide is the π‐complex.

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This Paper describes a case history of cast-in-place concrete piling to support large underground structures for a subway in Nagoya city, Japan. The ground was medium-to-dense sand interbedded with clayey soil. Owing to geotechnical and construction conditions at the site, the piles had to be designed as friction piles. Based on full-scale short-and long-term load tests, ultimate bearing capacity and creep load characteristics were obtained. However, due to the uncertainty of friction on these bored piles, the performance of every pile was verified by load testing. One pile was found to be unsatisfactory and was treated to improve behaviour. Monitoring piles were installed with strain gauges to observe performance. When excavation started the axial load in the upper part of the pile increased while that in the lower part decreased. The reason for this was, at first, obscure. What had been expected was an increase in axial load from the top to the bottom. The site study-using measurements of pile-ground interaction-revealed that the effect was caused by ground heave resulting from the excavation. The observational procedure was useful, not only to confirm predetermined targets, but also to shed light on unexpected geotechnical problems. L'article décrit un cas de pieux coulés sur place permettant de soutenir les grandes structures souterraines d'une autoroute de Nagoya, Japon. Le sol est constitué de sable moyennement à fortement dense intercalé de lits argileux. A cause des conditions géotechniques de construction sur le site, les pieux conçus sont des pieux frottants. La capacité portante ultime et les caractéristiques de fluage ont été mesurées lors d'essais de chargement pleine échelle à court et long terme. Cependant, en raison de l'incertitude pouvant exister sur le frottement le long de pieux forés, la performance de chaque pieu a été vérifiée lors d'essais de chargement. Un des pieux s'étant révélé peu satisfaisant, il a été traité pour améliorer son comportement. D'autres pieux ont été équipés de jauges de contrainte et suivis par enregistrement pour étudier leurs performances. Lorsque l'excavation commence, la charge axiale de la partie supérieure du pieu augmente tandis que celle de la partie inférieure décroît. Cette réponse est tout d'abord apparue bien étrange: on attendait une augmentation de la charge axiale sur tout le pieu. Une étude du site réalisée par mesure de l'interaction sol-pieu a cependant montré que cet effet était causé par une soulèvement du sol lors de l'excavation. La méthode d'observation a donc été utile, non seulement pour valider les objectifs fixés initialement, mais aussi pour éclaircir les problèmes géotechniques inattendus.

We have investigated thermoelectric properties of p type Bi Te thermoelectric material doped with PbTe. The samples (Bi 2 Te 3 ) 0.2 (Sb 2 Te 3 ) 0.8 ＋xmassPbTe(x＝0, 0.05, 0.1 , 0.3, 0.5) were fabricated by mechanical alloying and spark plasma sintering(SPS) method. The Seebeck coefficient(a), the electric conductivity(s) and the thermal conductivity(k) were measured in the temperature range 323 523 K. The a decreased and the s increased with increasing PbTe content. The dimensionless figure of merit(ZT) were calculated. The maximum point of the ZT shifted toward higher temperature with increasing PbTe content. The maximum ZT of 1.12 was obtained for x＝0.3 sample at 373 K.

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