Light and small-angle X-ray scattering, sedimentation equilibrium, viscosity, circular dichroism, and infrared absorption measurements have been made on 1,4-dioxane (DIOX) and 2-ethoxyethanol (2EE) solutions of seven amylose tris(phenylcarbamate) samples ranging in molecular weight from 2 Â 10 4 to 3 Â 10 6 . Analyses of gyration radius, scattering function, and intrinsic viscosity data in terms of the wormlike chain model yield Kuhn segment lengths of 22 AE 2 nm and 16 AE 2 nm in DIOX and 2EE, respectively, and a contour length per residue of 0:33 AE 0:02 nm in both, showing that the amylose derivative chain has high stiffness and a contour length slightly shorter than the known value 0.37-0.40 nm for amylosetriesters in the crystalline state. These results are consistent with the intramolecular hydrogen bonding between the C=O and NH groups of the neighbor repeating units detected by infrared absorption and also with the locally regular (or helical) conformation indicated by circular dichroism.

The z-average mean-square radius of gyration S(2)(z), the particle scattering function P(k), the second virial coefficient, and the intrinsic viscosity [eta] have been determined for amylose tris(phenylcarbamate) (ATPC) in methyl acetate (MEA) at 25 degrees C, in ethyl acetate (EA) at 33 degrees C, and in 4-methyl-2-pentanone (MIBK) at 25 degrees C by light and small-angle X-ray scattering and viscometry as functions of the weight-average molecular weight in a range from 2 x 10(4) to 3 x 10(6). The first two solvents attain the theta state, whereas the last one is a good solvent for the amylose derivative. Analysis of the S(2)(z), P(k), and [eta] data based on the wormlike chain yields h (the contour length or helix pitch per repeating unit) = 0.37 +/- 0.02 and lambda(-1) (the Kuhn segment length) = 15 +/- 2 nm in MEA, h = 0.39 +/- 0.02 and lambda(-1) = 17 +/- 2 nm in EA, and h = 0.42 +/- 0.02 nm and lambda(-1) = 24 +/- 2 nm in MIBK. These h values, comparable with the helix pitches (0.37-0.40 nm) per residue of amylose triesters in the crystalline state, are somewhat larger than the previously determined h of 0.33 +/- 0.02 nm for ATPC in 1,4-dioxane and 2-ethoxyethanol, in which intramolecular hydrogen bonds are formed between the C==O and NH groups of the neighbor repeating units. The slightly extended helices of ATPC in the ketone and ester solvents are most likely due to the replacement of those hydrogen bonds by intermolecular hydrogen bonds between the NH groups of the polymer and the carbonyl groups of the solvent.

Abstract-In this paper, we present a learning support system DASE-E to help students understand fundamental concepts of distributed algorithms in computer science. DASE-E is a collaborative learning system, in which the task of students is to devise a distributed algorithm. DASE-E offers a set of small wireless terminals with accelerometers. Each student plays the role of a process with a terminal, according to the algorithm that students devised. Each terminal enables a student to take physical actions that control the behavior of a process in the simulator. After the role playing simulation is finished, students discuss their activity played back on a screen.We implemented the system for learning distributed leader election algorithms, had a trial exercise in our research group, and we confirmed that it is effective to learn the critical part of distributed systems and algorithms.