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An 8-km long MgB2 wire for a prototype klystron magnet was made and evaluated. The wire was made by a typical in situ method; it has 10 filaments and 0.67 mm in outer diameter. The homogeneity of Ic of this wire was evaluated by several methods. Deviation of Ic values in short sample wires was very small. In addition, the current sharing temperature of the MgB2 magnet (made of two reels of wire 2.9 km long each) agreed well with the estimated value of the Ic-B-T properties in short sample wires. Based on the obtained results, it can be said that the Ic properties of the entire wire length are quite uniform.

The most appealing physical phenomenon in frustrated quantum magnets is the emergence of nonclassical ground states stabilized by the synergy effect of the spin frustration and the quantum fluctuation. The spin-1/2 square-lattice Heisenberg antiferromagnet (SLHAF) with the nearestneighbor J 1 and next-nearest-neighbor J 2 exchange interactions is a typical frustrated quantum magnet, for which energetic theoretical studies have been performed. Most of the theoretical results suggest that the S = 1/2 J 1 − J 2 SLHAF exhibits the quantum disordered ground state for α c1 < J 2 /J 1 < α c2 with α c1 ≃ 0.4 and α c2 ≃ 0.6. 1-11) However, the nature of the ground state has not been theoretically clarified. The ground states for α c1 > J 2 /J 1 and α c2 < J 2 /J 1 are the Néel antiferromagnetic state and the columnar antiferromagnetic state, respectively.On the experimental side, many materials have been investigated from the viewpoint of the S = 1/2 J 1 − J 2 SL-HAF . [12][13][14][15][16][17][18][19][20] However, the quantum disordered ground state has not been observed experimentally. The search for approximate realizations of the S = 1/2 J 1 − J 2 SLHAF with the critical parameter range has been continued.In this short note, we report the results of the magnetic and specific heat measurements on a double perovskite, Sr 2 CuTeO 6 . This compound crystallizes in the tetragonal structure with the space group I4/m, as shown in Fig. 1 . 12,21) The crystal structure consists of CuO 6 and TeO 6 octahedra, shaded blue and maroon, respectively, which are linked sharing their corners. All the CuO 6 octahedra are elongated along the crystallographic c axis owing to the Jahn-Teller effect. Consequently, the hole orbitals d x 2 −y 2 of Cu 2+ ions with spin-1/2 are spread in the ab plane, in which Cu 2+ ions form a uniform squre lattice, as shown in Fig. 1(b). This leads to the strong superexchange interaction in the ab plane and the weak superexchange interaction between the ab planes. Thus, it is expected that Sr 2 CuTeO 6 can be magnetically described as a quasi-two-dimensional S = 1/2 J 1 − J 2 SLHAF [ Fig. 1(c)].Figure 2(a) shows the magnetic susceptibility of Sr 2 CuTeO 6 powder as a function of temperature. Our susceptibility data is consistent with that reported in Ref. 12. With decreasing temperature, the susceptibility exhibits a rounded maximum at T max ≃ 73 K and decreases. This behavior is characteristic of two-dimensional SLHAFs , 18,22,23) and is common to the susceptibilities in A 2 CuMO 6 with A = Ba, Sr and M = W, Mo, Te . 12,13,15) Figure 2(b) shows the low-temperature specific heat in Sr 2 CuTeO 6 measured at zero magnetic field. A sharp λ-like anomaly indicative of the magnetic ordering is observed at * E-mail address: tanaka@lee.phys.titech.ac.jp T N = 4.8 K. This Néel temperature is much lower than those observed in isostructural A 2 CuMO 6 with A = Ba, Sr and M = W, Mo, in which T N = 24 − 28 K . 14, 15) The strong suppression of magnetic ordering in Sr 2 CuTeO 6 should be ascribed to the weakness of the int...

A wind-and-react MgB2 solenoid magnet for klystrons has been developed. While the current normal-conducting (Cu) magnet consumes 20 kW per magnet, this MgB2 magnet consumes less than 3 kW in refrigerator power. The conduction-cooled half coil of the magnet is 337 mm in inner diameter; the winding pack, 19.4 mm wide × 136.6 mm high, uses 2.7 km of 10 filament circular conductor, which is insulated with glass 0.83 mm in diameter, and is reacted after being wound onto a stainless steel bobbin. The coil has Cu plates of 0.2 mm in thickness between each coil layer and on the inner and outer sides. The magnet has two coils and produces 0.8 T in the center and its stored energy is 11.8 kJ. Together with the above-mentioned coil structure, these coils can consume stored energy in itself at quench without a special quench protection system. A performance test of the magnet was successful.

Collagen sponge is one of the medical materials that are frequently used in clinical medicine. However, the problem of prion disease harmfully affected the usage of mammals-derived medical materials. Since there have been no reports about prion disease occurring in marine products, we produced the collagen and elastin sponge (CES) made from salmon, and investigated whether the CES could be a substitute for mammalian collagen sponge. Fibroblasts were seeded in the CES to examine whether the CES could be used as a scaffold for tissue engineering. The results of the WST-1 assay showed that the fibroblasts were viable and were well proliferated in the CES. To examine whether the CES could be used as an artificial dermis, the CES and TERUDERMIS (traditional collagen sponge) were grafted onto the skin defects on the dorsum of rats. The histological findings of these ulcers showed non-significant difference between the CES and TERUDERMIS. Because of the safety, the abundance of the resources, and the possessing same ability as TERUDERMIS, the biomedical materials derived from marine products may be a substitute for those derived from mammals.Collagen sponge is one of the biomedical materials frequently used in clinical medicine, especially in dermatology and plastic reconstructive surgery. It has been used as a biomaterial which covers fullthickness skin defects for the treatments of diseases and conditions such as burn (13,30,42), trauma (16), chronic skin ulcer (2, 10), excised skin tumor (23,33,38) and others that cause full-thickness skin defects. The main ability of collagen sponge is to accelerate tissue granulation (7), as forming good granulation from a relatively early stage-even on a tendon (18, 37) and bone (16,23,38,42), which generally takes a long time to form. And this ability is able to make a wound heal fast by using secondary skin grafting. The combined treatment with collagen sponge and skin grafting is less invasive for patients than other operative methods covering skin defects, such as local skin flaps, pedicled flaps, and free flaps because it is technically easy and takes a short time to perform the combination treatment (23,38). Collagen sponge is a very important treatment tool in dermatology and plastic reconstructive surgery. Collagen sponge is expected to be used as a scaffold for tissue engineering because of its high ability of cell adherence and biological affinity. It has contributed to regenerating various tissues such as

Carbon membranes were prepared by coating thin layers of lignocresol derived from Hinoki cypress by the phase-separation method and then carbonizing the lignocresol by high frequency induction heating at a heating rate of 500°C/min. The thickness of the membrane formed on the outer surface of a porous alumina substrate was about 1000 nm. Carbon membrane with a high performance of gas permeation showed a high water-selectivity in pervaporation of water/alcohol separation. The separation factor increased with increasing the heating temperature. The water concentration of the permeate was more than 99.5 wt% and the water flux was more than one or two order larger than the alcohol flux in the membrane prepared at 600 or 700°C. Carbon membranes derived from lignin-based materials provide one of the promising candidates for the separation of the liquid mixtures.

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Carbon membranes were prepared by pyrolyzing lignocresol derived from wood using high frequency induction heating. The pore structure of the carbon membrane was studied by adsorption measurements and XPS. Gas adsorption measurements indicated that lignin carbon membrane has micropores in the range of 0.6-0.5 nm. C1s peak of XPS spectra of the lignin carbon membranes clearly showed that there are several hydrophilic functional groups, containing oxygen groups, on the surface of the membranes. Gas permeation rates through the membranes were also measured at 35°C. Carbon membranes from lignin-based materials have higher performance than conventional polymer membranes and provide a promising new class of separation membranes.