In this paper, we describe the trial manufacture of ultrasonic linear array probes for medical puncture while observing the needle tip and the front lesion by imaging. Two kinds of linear array probes having 13 elements and 128 elements were fabricated. The signal intensity received from the needle tip was simulated and experimentally confirmed as a function of the insertion depth of the needle. The puncture of a simulated blood vessel phantom and a blood vessel of a pig were observed by B-mode imaging. We experimented on the puncture of a dog with the 128-channel linear array probe, and the femoral artery and vein were imaged. The needle tip position was successfully detected during the puncture of the femoral muscle of the dog, and the human median cubital vein was also imaged.

We fabricated an ultrasonic probe with a through hole for needle puncture. The probe consists of a ring-shaped transducer around the hole for detecting the needle tip and 12 fan-shaped transducers around the ring-shaped transducer for observing the lesion area. A B-mode image was obtained for inserting a needle into pig liver. We investigated the phase of the signals from the needle tip using an ultrasonic probe having separated transmitter and receiver elements. From the experimental results the detection principle of the needle tip was explained by edge waves. C⃝ 2014 Wiley Periodicals, Inc. Electron Comm Jpn, 97(6): 67-73, 2014; Published online in Wiley Online Library (wileyonlinelibrary.com).

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Using a spin-1/2 description of valence holes and Kondo coupling between local spins and carriers, GaAs-based III-V diluted magnetic semiconductors (DMS) are studied in the coherent potential approximation (CPA). Our calculated relation between ground-state energy and impurity magnetization shows that ferromagnetism is always favourable at low temperatures. For very weak Kondo coupling, the density of states (DOS) of the host semiconductor is not modified much. Impurity bands can be generated at the bottom of the host band only when Kondo coupling is strong enough. Using Weiss molecular theory, we predict a linear relation of Curie temperature with respect to Kondo coupling and doping concentration x if the hole density is proportional to x.(Some figures in this article are in colour only in the electronic version)The ferromagnetism of III-V-type diluted magnetic semiconductors (DMS) is not well understood. To explain ferromagnetism in DMS, various models and approaches have been proposed [1][2][3][4][5][6]. Though the models differ from each other in detail, they all agree that the coupling between the carriers and local spins is of fundamental importance. An issue of debate, however, is how the exchange between localized spins is induced by the carriers. One model for this induced exchange is the Ruderman-Kitttel-Kasuya-Yosida (RKKY) interaction [1, 2]. Another version which results in conclusions equivalent to RKKY is the Zener model [4] which uses the fact that the valence holes are on p-orbitals. A third model is the double-exchange (DE) mechanism [7], but this model is inconsistent with the charge-transfer properties [4]. Though RKKY can give a Curie temperature in agreement with experiment, some argue that the RKKY model breaks down here [5,8] because the local coupling between the carrier and the impurity spin is much larger than the Fermi energy and cannot be treated perturbatively.

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