Experiments were carried out to investigate the magnetic properties of melt-spun Nd--Fe-Co- alloys, -Didymium-Fe-Co- alloys and their bonded magnets. Magnetic properties of the melt-spun Nd--Fe-Co- system alloys were deteriorated with the increase of content. A maximum energy product of 134. kJ /m³ was obtained for ()

11Fe₇₂Co₈B₉

ribbon prepared at the substrate surface velocity (Vs) of 17.

1

m/s. This value was 93.3% of that for

Nd₁₁Fe₇₂Co₈B₉

ribbon (Vs= 17.

1

m/s). A maximum energy product of 139.

8

kJ/m³ was obtained for 26 mass%R-65.4 mass%Fe-7 mass%Co-

1

.

6

mass%

B

(R=

Ce

-Didymium) alloy ribbons prepared at Vs=17.

1

m/s. Using the 26 mass%R-65.4 mass%Fe-7 mass%Co-

1

.

6

mass%

B

ribbons prepared at Vs=20.7 m/s, the effect of annealing on the magnetic properties were examined, and the optimum annealing condition was found to be at 650°C for 20 min. Its corresponding value of (BH)_max was 135.7 kJ/m³. From the TEM observation, the particle size of these crystallized ribbons was 20-30 nm. A maximum energy product of 90.

5

kJ/m³ was achieved with the 26 mass%R-65.4 mass%Fe-7mass%Co-

1

.

6

mass%

B

bonded magnets made from the optimally prepared ribbons.

抄録全体を表示

Hingganite-(), [](OH)₂ or CeBeSiO₄(OH), occurs in a pegmatite at Hirukawa-mura, Gifu Prefecture, Japan. It is pale tan in color, vitreous and transparent, with a white streak. The Mohs hardness is -, and the calculated density is 4.28 g/cm³. An electron microprobe analysis gave the empirical formula ( Gd_0.002Dy_0.001Ca_0.60)(OH)

1.52

. The lattice parameters were determined by the Rietveld method coupled with the imaging plate Gandolfi XRD data: SG = P2₁/a, a =

9

.8973(11),

b

= 7.6282(

8

), c = 4.7505(

6

) Å, β = 90.416(

8

)°, V = 358.64(7) ų, and Z = 2 for

Ce₂

[]

Be₂Si₂O₈

(OH)₂. The three strongest lines in the powder XRD pattern [d(Å), I/I₀, hkl] are (3.14, 86, 211 and 211), (2.

85

, 100, 121 and 121) and (2.56, 46, 311, 221 and 311). Hingganite-(

Ce

) is a new member of the gadolinite-datolite group of minerals. It is the

Ce

-analogue of hingganite-(Y), and ideally, is the Fe-free analogue of gadolinite-(

Ce

). A single crystal of hingganite-(Y) from the same locality showed a chemical composition of (

Y_1.21Ca_0.28Nd_0.06Gd_0.06Dy_0.06Yb_0.05Er_0.04Ce_0.04Sm_0.03Ho_0.03Lu_0.02Pr_0.01Tm_0.01Tb_0.01La_0.01

)

Σ_1.92Fe_0.23Be_2.07Si_2.07O_8.19

(OH)

1.55

. A negative anomaly was observed for Ho in the lanthanide distribution pattern of hingganite-(Y). A single crystal structure refinement of hingganite-(Y) converged to R = 0.0329 with the lattice parameters of: a =

9

.8830(16),

b

= 7.6091(

9

), c = 4.7423(

9

) Å, β = 90.342(14)°, and V = 356.62(10) ų.

抄録全体を表示

We have studied the magnetoresistance of - (x=0.25, , 0., , 0.75) single crystals under the magnetic fields up to 15, T and in a temperature range between 0.4, K and 15, K. In Phase I (paramagnetic), in all the samples the negative magnetoresistance is observed, whose magnitude becomes larger with decreasing temperature. However, in , the magnetoresistance below T-- , K becomes very small neverthless the negative magnetoresistance is observed above -- , K. This is completely different from the magnetoresistance in where the magnitude of the negative magnetoresistance becomes larger with decreasing temperature. The weak magnetic field dependence of the electrical resistivity is observed also in Phase IV in . These results indicate that the ground state of is not the Kondo singlet but the AF (antiferro) magnetic state called Phase VI^′ is realized below -- , K. Phase IV^′ is similar to Phase IV in . The anisotropy of the phase boundaries between I, II (AFQ (antiferroquadrupolar) ordered), III (antiferromagnetic ordered) and IV^′ in has been studied. The phase boundary I--IV^′ does not show the anisotropy but that of III--II shows the large anisotropy depending on the applied field direction. These are discussed from the stand point that the magnetic anisotropy and the intereference effect between the AFQ and AF interaction are important. We propose the mechanism of the phase transition from IV^′ to III or II.

抄録全体を表示

We measured the elastic and thermal properties to examine the competing effect between the intersite interactions and the Kondo coupling in and with the ground state. The huge softening of the transverse C₄₄ mode of both compounds at low temperatures indicates a remarkable fluctuation of the quadrupolar moments O_yz, O_zx and O_xy with symmetry. In the magnetic phase diagram of , we found a new ordered phase IV in addition to the antiferroquadrupolar phase II and the antiferromagnetic phase III. The compound , however, shows the Fermi liquid state without the long-range order at low fields and transits into the ordered phase II or III in the magnetic field above 16kOe.

抄録全体を表示

We have studied the magnetic phase diagrams of the dense Kondo compounds and by use of low temperature ultrasonic measurements. A transition associated with a quadrupolar reorientation has clearly been observed around , kOe in the antiferroquadrupolar phase II of . In the paramagnetic phase I of a crossover from the ordinaly ground state to the Kondo singlet state has been found. The field induced transition from the Kondo singlet state to the antiferromagnetic phase III or the phase II has been found at a critical field 17, kOe. The field angle dependence of the phase diagram of is also presented.

抄録全体を表示

In melt-spun ribbons of Didymium (Nd-10 %Pr)-Fe- and -didymium (Nd-15 %Pr- %)-Fe- alloys prepared by the single roller method, the effects of composition, substrate surface velocity and subsequent annealing on the magnetic properties were studied, and their bonded magnets were made of the optimum-quenched ribbons. A maximum energy product of 93. kJ/m³ was obtained with 34 wt% (-didymium)-65 wt%Fe- wt% ribbon prepared at a substrate surface velocity of 11. m/s.
The best magnetic properties obtained in these bonded magnets of 34 wt% (-didymium) -65 wt%Fe- wt% alloy were B_r=0.595 T, H_CJ= 1410 kA/m, H_CB =400 kA/m and (BH)_max=60.3 _KJ/m³. The temperature coefficients (from 25 to 125°C) of B_r and H_CB for these bonded magnets were −0.154%/°C and −0.180%/°C, respectively.

抄録全体を表示

In melt-spun ribbons of -(Fe, Co)-(, Si) system alloys prepared by the single roller method, the effects of composition, substrate surface velocity and subsequent annealing on the magnetic properties were studied. The maximum coercivity (_IH_C=672 kA/m) and the magnetic energy product ((BH)_max=33. kJ/m³); were obtained in a ribbon prepared at a substrate surface velocity of 11. m/s. X-ray diffraction patterns from samples of the highest coercivity show a mixture of an amorphous and a fine crystalline phase.
In (−zCo_z)

70B₁₀

system ribbons, as the Co content is increased, the coercivity tends to decrease, while the Curie temperature is raised, In

Ce₂₀Fe₇₀

(

B₁

−wSi_w)₁₀ system ribbons Si substitution increases the coercivity as well as the magnetization. It is also found that the addition of Si tends to facilitate the fabrication of longer ribbons.

抄録全体を表示

We define a new kind of classical digamma function, and establish some of its fundamental identities. Then we apply the formulas obtained, and extend tools developed by Flajolet and Salvy to study more general Euler-type sums. The main results of Flajolet and Salvy's paper (Expo. Math. 7(

) (1998), 15-35) are immediate corollaries of the main results in this paper. Furthermore, we provide some parameterized extensions of Ramanujan-type identities that involve hyperbolic series. Some interesting new consequences and illustrative examples are considered.

抄録全体を表示

Al- mass%Fe, Al- mass%Fe-0.7 mass%Zr, Al- mass%Fe-2 mass% and Al- mass%Fe-2 mass%-0.7 mass%Zr alloys were solidified into a ribbon shape at cooling rate of about 10⁵°C/s by twin roller technique. Assolidified microstructures have two categories, zone A and zone depended on the cooling rate. Zone A composed of fine metastable intermetallic compounds dispersed in supersaturated Al solid solution. Zone had cellular structure and cell bounderies composed of fine metastable compounds in Al-Fe and Al-Fe-Zr alloys and stable compound in added alloys. The Vickers hardness of two zones in Al- mass%Fe binary alloy are reduced by heating at 350°C for hr, but in or Zr added ternary alloys the hardness are reduced by heating at higher temperatures than 350°C. Tensile strengths of the as-solidified ribbon specimens are about 58kgf/mm² in Zr added alloy and about 63kgf/mm² in Zr and added alloy, and they depend on the fraction of zone A and zone .

抄録全体を表示

A transferred hyperfine field of the type Mrf(r)/r which a magnetic moment produces at

11B

nuclei in

CeB₆

is proposed, in order to explain the angular dependence of the

11B

resonance magnetic field in phase II of the compound. Here, M is the uniform component of the

Ce

magnetic moments induced by the applied field, and r is the position vector from a

Ce

site to a

B

site at which

H_thf¹

is produced. A crystal deformation is suggested for this type of

H_thf¹

to occur.

抄録全体を表示

Measurements of the magnetization process at 4.2 K and .3 K for magnetic field up to about 150 kOe and of the temperature dependence of the susceptibility between 4.2 K and room temperature have been done in order to investigate Kondo states of dilute and dense Kondo system in single crystalline − (0.03≤x≤.0). The magnetic phase diagram is constructed above 0. K for , and . A largely anisotropic magnetization and the temperature dependence of susceptibility in dilute alloys indicate the quartet Kondo state contrary to the previous report. Dependence of Kondo temperature on the concentration is very weak.

抄録全体を表示

2002年に，A系列のブロイラー出荷鶏で蜂窩織炎 () が多発した. 食鳥処理場 (処理場) におけるによる廃棄率と病態を調査し，同系列の農場 (農場) でを伴う漿膜炎 (Se) 型の大腸菌性敗血症 (大腸菌症) を認めたので病理学的に比較した. いっぽう，系列はの発生が少なかったので両系列の飼育状況を比較し，の発生要因を調査した. A系列のによる廃棄率は0.88%で，系列の0.03%に比べ有意に高かった. 処理場の廃棄鶏の63%は雄で，下腹部や内股部に皮膚の肥厚，皮下水腫，チーズ様凝塊の形成を認めたが，Se病変はなかった. 病変やSe病変から大腸菌O78が分離された.農場の病変には痂皮形成や表皮炎を認めたので，床面との接触部位からの大腸菌感染が疑われた. 発生要因として，給温期間，飼育密度，空舎期間が関与しているものと考察した.

抄録全体を表示

西オーストラリア州のMonte Bello島でとれた成熟した雌, 雄各尾にもとづきタツノイトコ属の新種.Acentmnum (Idiotropiscis) larsonaeを記載した.本種は同属で最も近緑のA.australeとは次の点で異なる: ) 前方にとび出した前頭隆起がより高い, 2) 吻が短く, 頭長は吻長の3.7～3.倍, 3) 胴輪が11個, 4) 背鰭前胴輪の背面の幅が非常にせまい.インド・太平洋に分布するIdiotropiscis Whitley, 1947と大西洋のAmphelikturus Parr, 1930はタツノイトコ属Acentmnura Kaup, 1853の亜属とみなす.

抄録全体を表示