An electron beam recorder (EBR) was developed for mastering optical disks with a recording density of 100 Gbit/in2 using a multilevel recording format. In this recording format, a nanometer-scale accuracy of relative pit edge position is required in both radial and tangential directions. To achieve the recording position accuracy, a rotation stage with a noncontact vacuum seal and a correction system for rotation errors were developed. In addition, an active magnetic shield system and a learning compensation for beam displacement were adopted to improve the stability of the beam position. As a result, the ability to record with high accuracy and high resolution was confirmed from experimental results. A fine pit pattern with a minimum pit length of 70 nm was formed precisely. The recording accuracy of the EBR was evaluated to be approximately 2 nm (standard deviation) in both radial and tangential directions. Furthermore, a carrier-to-noise ratio of 64 dB was also obtained by reproducing an etched silicon master with a 240 nm monotone pit pattern.

We construct a new class of scalar noncommutative multi-solitons on an arbitrary Kähler manifold by using Berezin's geometric approach to quantization and its generalization to deformation quantization. We analyze the stability condition which arises from the leading 1/ correction to the soliton energy and for homogeneous Kähler manifolds obtain that the stable solitons are given in terms of generalized coherent states. We apply this general formalism to a number of examples, which include the sphere, hyperbolic plane, torus and general symmetric bounded domains. As a general feature we notice that on homogeneous manifolds of positive curvature, solitons tend to attract each other, while if the curvature is negative they will repel each other. Applications of these results are discussed.

In text-based communication, people can now use not only emoticons and emoji, but also graphical symbols called stickers. This study focused on the use of stickers in text-based communication. A questionnaire asking subjects to individually rate the perceived usefulness of 25 features of stickers was prepared and used in a survey targeting 211 Japanese college students. The authors then explored potential factors in the roles of stickers. The study revealed three potential roles of stickers: “easy transmission of subtle nuances and nonverbal cues,” “abundant and versatile expressions that can be substituted for text messages,” and “changing the topic, flow, or rationale of the interaction.” The authors examined the effects of gender and text messaging dependency on these roles. Results showed significant effects of dependency in all roles, but effects of gender were seen in only “abundant and versatile expressions that can be substituted for text messages.”

In text-based communication, which lacks nonverbal cues, various techniques for expressing communicative intent are now available. Most prominently used are emoticons, emojis, and stickers. Although previous studies have separately examined emoticons and emojis, few have compared their features, and also included comparison with stickers. The authors conducted a survey targeting 300 Japanese young adults to investigate the features of emoticons, emojis, and stickers from the viewpoint of their perceived usefulness. The authors also examined the effects of gender and text-messaging dependency on ratings of the perceived usefulness of these graphical symbols. This study revealed a detailed feature list for each type of symbol. The existence of characteristic roles for each type of symbol is discussed. This study also confirmed the effects of gender and text-messaging dependency on symbol usefulness ratings.

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