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Notes: Experimental investigations of the effect of target species atomic mass and system geometry on the anisotropic transport in the ion mixing of metallic systems are reported. Bilayer samples with zero heats of mixing and similar cohesive energies, but different atomic mass and geometry, such as Ta on top of Nb(Ta/Nb), Nb on top of Ta(Nb/Ta), Hf on top of Zr (Hf/Zr), and Zr on top of Hf(Zr/Hf) were irradiated by 300 keV Kr2+ at a dose of 2 × 1016 Kr2+/cm2 at 77 K. The samples were investigated using embedded markers and Rutherford backscattering spectrometry. The experimental results indicate that the anisotropic transport is dominated by a preferential displacement of the top layer species into the bottom layer. This is probably due to an anisotropy in the momentum distribution within the collision cascade. In addition, there is an enhancement of the inward displacement when the lighter species is on top indicating a small preferential recoil displacement of the lighter species over the heavier one.

Notes: The effect of ion mixing on the depth resolution of sputter depth profiling has been studied using x-ray photoelectron spectroscopy and Ar+ sputtering of Pt/Zr, Pt/Mo, Pt/Ti, and Pt/Ni interfaces. It is shown that the heat of mixing of binary alloys plays an important role in depth resolution. The measured interface width of bilayers consisting of metals with a large and negative heat of mixing (Pt/Zr and Pt/Ti) is significantly broader than that of metals with a nearly zero heat of mixing (Pt/Mo and Pt/Ni). This observation suggests that the mechanism of ion mixing during sputter depth profiling with ion energies of a few keV is the same as ion mixing with ion energies of several hundred keV; diffusion in thermal spikes is the dominant contribution to ion mixing in the systems investigated.

Notes: We derive, using dimensional analysis and finite element calculations, several scaling relationships for conical indentation in elastic-plastic solids with work hardening. Using these scaling relationships, we examine the relationships between hardness, contact area, initial unloading slope, and mechanical properties of solids. The scaling relationships also provide new insights into the shape of indentation curves and form the basis for understanding indentation measurements, including nano- and micro-indentation techniques. They may also be helpful as a guide to numerical and finite element calculations of indentation problems. © 1998 American Institute of Physics.

Notes: Epitaxial α-Fe films have been grown on HF cleaned Si(111) substrates at 30 °C by electron beam evaporation in an ultrahigh vacuum environment to a thickness of several thousands of Angstroms. Conventional θ−2θ x-ray diffraction shows that only the Fe(222) peak is present, indicating that the films are oriented with the Fe(111) plane parallel to the Si(111) plane. Transmission electron microscopy shows that the Fe[11¯0] direction is parallel to the Si[11¯0] direction in the plane of the substrate.

Notes: Epitaxial double hexagonal close-packed (dhcp) Nd layers have been grown on the (111) surface of α-Fe at 320 °C by electron beam evaporation in an ultrahigh vacuum environment. Conventional θ-2θ diffraction and transmission electron microscopy show that the dhcp Nd films are oriented with the dhcp Nd (0001) plane parallel to the α-Fe(111) plane and with the dhcp Nd [112¯0] direction parallel to the Fe[11¯0] direction in the plane of the substrate. An epitaxial Fe/Nd/Fe trilayer structure with the same orientational relationships has also been made.

Notes: The work done during indentation is examined using dimensional analysis and finite element calculations for conical indentation in elastic-plastic solids with work hardening. An approximate relationship between the ratio of hardness to elastic modulus and the ratio of irreversible work to total work in indentation is found. Consequently, the ratio of hardness to elastic modulus may be obtained directly from measuring the work of indentation. Together with a well-known relationship between elastic modulus, initial unloading slope, and contact area, a new method is then suggested for estimating the hardness and modulus of solids using instrumented indentation with conical or pyramidal indenters. © 1998 American Institute of Physics.

Notes: The thermally induced recovery of microscopic deformation in a nickel–titanium shape-memory alloy was examined. Surface deformation was simulated by indenting the alloy in the martensite phase at room temperature using both spherical and pyramidal indenters. We show that deformation in spherical microindents can be almost completely reversed by moderate heating. Partial recovery was observed for pyramidal impressions formed by a Vickers indenter and the recovery ratio was independent of the indentation depth. The observations were rationalized using the concept of representative strain and maximum stress under the spherical and pyramidal indenters. © 2002 American Institute of Physics.

Notes: Objective To examine whether gonadotrophin-releasing hormone agonist or oestradiol can directly affect DNA in leiomyoma cells.Design In vitro explant culture of leiomyoma cells.Setting University research group.Sample Leiomyoma cells were cultured from the specimens of four premenopausal women at myomectomy.Methods The presence of gonadotrophin-releasing hormone receptor in leiomyoma cells was determined by reverse transcriptase–olymerase chain reaction. Leiomyoma cells were treated with gonadotrophin-releasing hormone agonist or cultured in different concentrations of oestrogen, progesterone or fetal calf serum for one, four or seven days.Main outcome measures Cell number, expression of proliferating cell nuclear antigen, and DNA damage after one, four or seven days of treatment.Results Gonadotrophin-releasing hormone receptor messenger ribonucleic acid was detected on cultured leiomyoma cells. Leiomyoma cell growth was not affected by the addition of gonadotrophin-releasing hormone agonist or progesterone, but increased with oestrogen or fetal calf serum supplementation. Overexpression of proliferating cell nuclear antigen was prevented in cultures added with oestrogen or fetal calf serum, but not related to gonadotrophin-releasing hormone agonist treatment. Significant decreases in DNA damage as indicated by decreased comet number were found in the leiomyoma cultures treated with oestrogen or fetal calf serum for four and seven days but not with gonadotrophin-releasing hormone agonist or progesterone. Furthermore, 5% fetal calf serum supplementation was more growth supporting and more significantly reduced the comet number than 250 pM 17 β-oestradiol.Conclusion Cell growth, proliferating cell nuclear antigen expression and DNA damage are dependent on oestrogen or fetal calf serum, but independent of gonadotrophin-releasing hormone agonist or progesterone. Our findings suggest that gonadotrophin-releasing hormone agonist-induced leiomyoma shrinkage may be due in part to a mechanism involving DNA damage, and support the hypothesis that gonadotrophin-releasing hormone agonist exerts its action indirectly through oestrogen action on the tumour level.