An attempt was made to prepare porous carbon by using the channels of Y zeolite as a template. Poly(acrylonitrile) and poly(furfuryl alcohol) were carbonized in the zeolite channels and the resultant carbon/zeolite complexes were subjected to acid treatment in order to extract carbon from the zeolite framework. In addition, pyrolytic carbon deposition in the channels was carried out by exposing the zeolite to propylene at high temperature, and then the carbon was liberated in the same manner as above. The morphology and structure of the carbon prepared in the channels were characterized, and the results were discussed in relation to the morphology and structure of the original zeolite template. It was found that the microscopic morphology of the resultant carbons reflects that of the corresponding zeolites. All of these carbons are highly porous, and some of the CVD carbons have BET surface areas as high as >2000 m 2 /g.

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We report the first experimental demonstration of longitudinal compression of laser-accelerated electron pulses. Accelerated by a femtosecond laser pulse with an intensity of 10¹⁸ W/cm², an electron pulse with an energy of around 350 keV and a relative momentum spread of about 10⁻² was compressed to a 500-fs pulse at a distance of about 50 cm from the electron source by using a magnetic pulse compressor. This pulse was used to generate a clear diffraction pattern of a gold crystal in a single shot. This method solves the space-charge problem in ultrafast electron diffraction.

Terahertz pulses trapped as surface waves on a wire waveguide can be flexibly transmitted and focused to sub-wavelength dimensions by using, for example, a tapered tip. This is particularly useful for applications that require high-field pulses. However, the generation of strong terahertz surface waves on a wire waveguide remains a challenge. Here, ultrafast field propagation along a metal wire driven by a femtosecond laser pulse with an intensity of 1018 W/cm2 is characterized by femtosecond electron deflectometry. From experimental and numerical results, we conclude that the field propagating at the speed of light is a half-cycle transverse-magnetic surface wave excited on the wire and a considerable portion of the kinetic energy of laser-produced fast electrons can be transferred to the sub-surface wave. The peak electric field strength of the surface wave and the pulse duration are estimated to be 200 MV/m and 7 ps, respectively.

We have demonstrated single-shot measurement of electron diffraction patterns for a single-crystal gold foil using 340 keV electron pulses accelerated by intense femtosecond laser pulses with an intensity of 2×1018 W/cm2. The measured electron beam profile is faithfully reproduced by the numerical simulation of the electron trajectory, providing evidence that the electron pulse spontaneously expands in time owing to the velocity spread produced in the acceleration process, but is not distorted in an irreversible nonlinear manner. This study shows that the laser acceleration is promising for the development of pulse compression methods for single-shot femtosecond electron diffraction.

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There is no research about age difference in the process of sequential learning in non-human primates. Is there any difference between young and adults in sequential learning process? Six chimpanzees (Pan troglodytes), 3 young and 3 adults, learned the Arabic numeral sequence 1 to 9 by touching the numerals on a touch-screen monitor in ascending order. Initially, the sequence always started with the numeral 1, i.e. 'start-fixed task'. Training began with the sequence 1-2, 1-2-3, and continued sequentially up to 1-2-3-4-5-6-7-8-9. Later, the subjects were introduced to sequences that started with a random numeral, but always ended with 9, i.e. 'end-fixed task'. Performance in the end-fixed task was worse relative to the familiar start-fixed task. After training with various sequences of adjacent numerals, the subjects were given a transfer test for the non-adjacent numerals. The results suggested that all chimpanzees indeed mastered sequential ordering, and although there was no fundamental difference in the acquisition process between the two age groups, there was a significant age difference in memory capacity. Based on their knowledge of sequential ordering, the subjects were then asked to perform a masking task in which once a subject touched the lowest numeral, the other numeral(s) turned to white squares. Performance of the masking task by young chimpanzees was better than that of adults in accuracy and degree of difficulty (number of numerals). Taken together, these data clearly demonstrate a similarity among subjects in the way chimpanzees acquire knowledge of sequential order regardless of age differences in sequential learning. Moreover, they reveal that once knowledge of sequential order is established, it can be a good index used to evaluate memory capacity in young and adult chimpanzees.