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Notes: Magnetic measurements have been performed on silver clad Tl-1223 and Tl-2223 tapes and a Tl-1223 single crystal to study the critical current properties of these samples. The Tl-1223 tape is shown by both magnetic and transport experiments to exhibit a highly granular nature, much more severe than that seen in the Tl-2223 tape, and in Bi-2223 tapes fabricated by similar rolling and pressing techniques. This characteristic is explained in terms of the poor grain alignment in the Tl-1223 tape resulting from the spherical morphology of Tl-1223 powders, in contrast with the micaceous and easily aligned Bi-2223 and Bi-2212 materials. However, evidence of a small number of strong intergrain links which remain superconducting at 77 K and 8 T is clear. The Tl-1223 single crystal exhibits clear anisotropic behavior, and this, together with the lack of good crystallographic alignment in the tapes is used to explain the variations in irreversibility line behavior between sample forms. The ratio of the irreversibility fields measured with field parallel and perpendicular to the ab plane is approximately 8. A clear "fish tail'' feature is also observed in magnetic hysteresis curves obtained from the Tl-1223 single crystal. © 1995 American Institute of Physics.

Notes: Fe-Cr-Co magnets with radial anisotropy were developed by rotating samples in a magnetic aging furnace. The anisotropy is altered by the applied magnetic field strength. The Fe-25 wt. %Cr-12 wt. %Co-0.5 wt. %Ti alloy aged in a magnetic field of 100 Oe yields the magnetic properties of (BH)max=24 kJ m−3 (3 MGOe) and iHc=48 kA m−1 (600 Oe) parallel to radial direction, which are higher than those of (BH)max=7 kJ m−3 (0.9 MGOe), iHc=33 kA m−1, measured parallel to the circumferential direction. The increment of the applied magnetic field over 200 Oe alters the radial anisotropy into a circumferential one. Microstructural studies indicate that the iron-rich phase is elongated parallel to the direction of induced anisotropy. Computations of the magnetic flux distribution in disk samples confirm the experimental observations.

Notes: Present works describe the development of Fe-Cr-Co-Mo alloys with favorable {110}〈100〉 texture, which will lie along the transverse direction (TD) of the rolled strips. The studied alloy composition is Fe-30 wt. % Cr-15 wt. %Co-3 wt. % Mo-0.1 wt. % Mn-0.05 wt. % S. The magnetic properties of the alloys have been enhanced along the TD and the best magnetic properties obtained with TD alloys are Br=1.2 T (12.0 kG), iHc=82 kA m−1 (1025 Oe), and BHmax=56 kJ m−3 (7.0 MGOe). The favorable texture is developed by secondary recrystallization, caused by a mixture of rolling and annealing. It can be considered that the process adopted in this investigation is useful for mass production of Fe-Cr-Co alloys with high energy products, without forming a columnar structure or a single crystal.

Notes: Present works describe the developments the low cost R-Fe-B sintered permanent magnets. Three different didymiums are chosen for the low cost mixtures of rare-earth elements. The studied alloy compositions are Fe-(32.5–34.5)wt. %R-(1–1.6)wt. %B, where R elements are didymium (Nd-10wt. %Pr), 5Ce-didymium (Nd-15%Pr-5%Ce), and 40 Ce-didymium (Nd-10%Pr-40%Ce). The specimens were prepared by the conventional powder metallurgical techniques. The best magnetic properties obtained in this studies are Br=13.2 kG, iHc=10.2 kOe, and (BH)max=40 MGOe with the Fe-33.5% (5Ce-didymium)-1%B alloy. Temperature dependence of iHc of this alloy is almost comparable to that of the Nd-Fe-B alloys.

Notes: Fe-Cr-Co ductile alloys produce magnetic properties comparable to those of Alnico permanent magnets family, up to (BH)max=91.2 kJ/m3(11.4 MGOe). It is technologically known that the addition of Ti to the Fe-Cr-Co alloys extends the α-phase region of system and improves the magnetic properties. The purpose of this work is to study the effect of Ti on microstructures and magnetic properties of Fe-Cr-Co alloys. The microstructures of Fe-25 wt.% Cr-12 wt.% Co alloys with or without Ti melted in air or in vacuum, were studied by optical microscopy, electron probe microanalysis (EPMA), and transmission electron microscopy (TEM). The alloys without Ti exhibit the precipitates of Cr23C6 carbide and Cr2N nitride a along the grain boundary or inside grain. These carbides and nitrides form the Cr-depleted zone around them. However, the addition of Ti suppressed the formation of Cr-depleted zone, in forming the Ti(C,N), and the magnetic properties are improved.

Notes: The effective permeability ( μeff) of the ring Sendust alloys (Fe-9–10 wt. % Si-5–7 wt. %Al), molded with Epoxy resin, was measured in the temperature range of −10 to 70 °C. The μeff of the alloys in molded condition measured at 20 °C is smaller than that in unmolded condition. The high values of the μeff at 20 °C of the molded alloys were obtained from the alloys in which magnetostriction constants (λs) were close to zero. The temperature dependencies of the μeff for the studied alloys in the unmolded condition are very similar, but after molding they are classified into four variations depending on the value of λs. When the alloys have large positive or negative values of λs, the μeff increases or decreases monotonically with increasing temperatures, but for the alloy with λs (approximately-equal-to)0, the μeff temperature dependence is complex. These behaviors of the μeff with temperature are interpreted on the basis of the induced stress, initiating from the differences in thermal expansion between alloys and Epoxy resin. The μeff of the molded alloys was mainly dominated by the induced uniaxial magnetic anisotropy (Ku) by the tangential and axial compressive stresses in the molded ring alloys.

Notes: The superconducting behavior of (Y1−xLax)Ba2Cu3Oy compounds for 0≤x≤1 was studied. It was found that Tc decreased with increasing La content. (Y1−xLax)Ba2Cu3Oy for 0≤x≤0.4, fired at 1050 °C in air, shows onset temperatures above 90 K. Annealing (Y1−xLax)Ba2Cu3Oy at 300 °C in O2 enhanced the onset temperature above 70 K for all studied compositions (x=0–1), and altered the crystal structure from tetragonal to orthorhombic.

Notes: : There have been no reports concerning the efficacy and safety of a 1-week quadruple therapy regimen of omeprazole, amoxycillin, roxithromycin and metronidazole for Helicobacter pylori infections and the impact of primary resistance on the eradication rate.〈section xml:id="abs1-2"〉〈title type="main"〉Methods: One hundred and sixty-nine consecutive patients with peptic ulcer disease as well as gastritis with biopsy-proven H. pylori infection were entered into an open study of omeprazole 20 mg o.m., amoxycillin 500 mg t.d.s., roxithromycin 150 mg b.d., and metronidazole 250 mg t.d.s. Helicobacter pylori status was determined by urease test, histology and culture. Susceptibility to amoxycillin, metronidazole and roxithromycin was determined by the E-test.〈section xml:id="abs1-3"〉〈title type="main"〉Results: H. pylori was eradicated in 155 out of 169 (92%; 95% CI 88–96%) by intention-to-treat analysis, and in 155 out of 163 (95%; 95% CI 92–98%) by per protocol analysis. The prevalence of primary resistance against amoxycillin, roxithromycin and metronidazole was 2 out of 166 (1%), 16 out of 166 (10%) and 27 out of 166 (16%), respectively. H. pylori was eradicated in 25 out of 27 (93%) patients with metronidazole-resistant strains compared with 130 out of 136 (96%) in patients with metronidazole-sensitive strains of H. pylori. It was eradicated in 15 out of 16 (94%) patients with roxithromycin-resistant strains while in 140 out of 147 (95%) patients with roxithromycin-sensitive strains of H. pylori, and in two out of two (100%) patients with amoxycillin-resistant stains compared with 153 out of 161 (95%) in patients with amoxycillin-sensitive strains. H. pylori was eradicated in three out of four (75%) patients with double resistance against metronidazole and roxithromycin compared with 152 out of 159 (96%) patients with sensitive strains to metronidazole and or roxithromycin. None of these differences were statistically significant. Severe side-effects were found in only one out of 169 patients—anaphylaxis due to penicillin.〈section xml:id="abs1-4"〉〈title type="main"〉Conclusions: The 1-week quadruple therapy with omeprazole, amoxycillin, metronidazole and roxithromycin was found to eradicate H. pylori in over 90% of all patients. This regimen was also found to be beneficial for patients with pre-treatment resistant strains to metronidazole, roxithromycin or amoxycillin, and was observed to be safe and well-tolerated.

Notes: This paper deals with the effect of anisotropy on fracture processes of a directionally solidified superalloy, Mar-M247, under a push–pull creep-fatigue condition at high-temperature. Three kinds of specimen were cut from a cast plate such that their axes possess angles of 0°, 45° and 90° with respect to the 〈001〉 orientation that is aligned parallel to the solidification direction (also to the grain boundaries and primary dendrite axis); these specimens being denoted the 0° specimen, the 45° specimen, and the 90° specimen, respectively. The tests were conducted at 1273 K (1000 °C) in air under equal magnitudes of the range of a ΔJ-related parameter, ΔWc , which represents the driving force for crack growth in creep-fatigue. Although the grain boundaries are macroscopically parallel to the solidification direction, they are wavy or serrated microscopically. Small cracks nucleate along parts of the grain boundaries perpendicular to the stress axis in all specimens. The 90° specimen has the shortest crack initiation life and the 0° specimen has the longest. In the 90° and 45° specimens, intergranular cracks continue to nucleate and a main crack is formed along the grain boundary due to the frequent coalescence of small cracks. In the 0° specimen, cracks grow into the grain, and transgranular cracks coalesce along the primary dendrite or grain boundary. The 0° specimen exhibits the slowest crack growth rate and the 90° specimen the fastest. These differences in the initiation and growth behaviour of small cracks cause the longest failure life in the 0° specimen and the shortest in the 90° specimen.

Notes: This paper deals with the initiation and growth of small cracks in a directionally solidified superalloy, Mar-M247.