Convergent beam electron diffraction analysis of theT 1 (Al2CuLi) phase in Al-Li-Cu alloys

Point and space group analysis of largeT ₁ (Al₂CuLi) crystals was performed by convergent beam electron diffraction. The structure ofT ₁ was determined to be hexagonal, possessing a 6/mmm point group and P6/mmm (No. 191) space group. The lattice constants were found to bea ≈ 0.497 nm andc ≈ 0.93 nm. This structure is in agreement with an existing model of T₁, although discrepancies between the observed and calculated intensities of certain reflections were evident. Electron probe X-ray microanalysis of theseT ₁ crystals indicates the composition is on the copper-rich side of stoichiometric Al₂CuLi. The slight deviation in the composition ofT ₁ from stoichiometry and the presence of planar defects in the microstructure may account for the discrepancy in the intensity of certain reflections.     

Modifications in the melted surface layer under low energy high current pulsed electron beam (LEHCPEB) treatment

This paper gives a detailed analysis of the rapidly solidified layers formed by low energy high current pulsed electron beam (LEHCPEB) on a D2 steel. The results of electron backscattering diffraction (EBSD) measurements revealed that the microstructures and phase components of the steel vary dramatically through the melted layer and the heat affected zone. The exact nature of the graded structure also changes with the number of pulses. The phase transformation paths, which vary with depth and in different areas (close to or far away from the carbides) of the melted layer, are determined by local composition gradients induced by the LEHCPEB treatment.     

Neutron measurements in the stray field produced by 158 GeV c(-1) per nucleon lead ion beams

This paper discusses measurements carried out at CERN in the stray radiation field produced by 158 GeV c(-1) per nucleon 208Pb82+ ions. The purpose was to test and intercompare the response of several detectors, mainly neutron measuring devices, and to determine the neutron spectral fluence as well as the microdosimetric (absorbed dose and dose equivalent) distributions in different locations around the shielding. Both active instruments and passive dosimeters were employed, including different types of Andersson-Braun rem counters, a tissue equivalent proportional counter, a set of superheated drop detectors, a Bonner sphere system, and different types of ion chambers. Activation measurements with 12C plastic scintillators and with 32S pellets were also performed to assess the neutron yield of high energy lead ions interacting with a thin gold target. The results are compared with previous measurements and with measurements made during proton runs.     

Deformation mechanisms in commercial Ti (0.5 at. pct oineq) at intermediate and high temperatures (0.3 - 0.6 tinm)

The plastic flow of the commercial titanium material Ti-50A (0.5 at. pct O_eq) of 22 μm grain size was investigated over the temperature range of 600 to 1150 structure) and strain rates of 3 x 10^-5 to 3 x 10^-2 per s employing both constant strain rate and strain rate cycling tests. Dynamic strain aging occurred in the temperature range of 600 to 850 (0.31 to 0.44T_m) with an activation energy of 50 kcal per mole derived from the start of serrations in the stress-strain curves, maxima in strain hardening and minima in ductility. This value is in accord with that for the diffusion of oxygen in titanium. At temperatures above 850 (0.46 to 0.59T_m) the data were very well represented by Weertman’s glide and climb high temperature creep mechanism, giving ε_skT/Dμb= 1.1 x 10⁶ (σ/μ)^4.55 withD = 1.0 x exp (- 57,800/RT). The value of 57.8 kcal per mole is in accord with available self-diffusion data for titanium.     

Scanning electron microscopy of central nervous system cerebrospinal-fluid-contacting surfaces: a bibliography (1963-1995)

This bibliography is compiled to assist in locating papers related to the application of scanning electron microscopy (SEM) to cerebrospinal-fluid-contacting surfaces in vertebrates. The use of SEM by neuroscientists has continued apace since the publication of the first bibliography in 1980. SEM studies now include more than 50 species of vertebrates and range from cyclostomes to humans; they encompass development from embryo to senescence and concern both normal and pathologic morphology. Although remarkable strides have been made toward a greater understanding of many aspects of the structure and function of cerebrospinal-fluid-contacting surfaces, many significant problems await the judicious application of scanning electron microscopy.     

Control of carboplatin-induced emesis with a fixed low dose of granisetron (0.5 mg) plus dexamethasone

The indications, advantages, complications, and benefits of peripheral neurectomy in patients with trigeminal neuralgia were studied in detail in 40 patients treated between 1982 and 1991. Twenty-eight patients had previously received radiofrequency thermocoagulation: peripheral neurectomy was performed for pain recurrence. These patients had excellent or good pain relief for at least 5 years postsurgery. Of the 12 patients who had peripheral neurectomy as their only procedure, seven had an excellent result and five had a good result. Five of the patients had recurrence of pain after 2 years but responded well to a second neurectomy. Elderly patients who experienced pain in the first and second divisions of the trigeminal distributions were the best candidates. Peripheral neurectomy is an effective, safe procedure for elderly patients who suffer from trigeminal neuralgia and have a limited life span.     

(-)-3-Isothujone, a small nonnitrogenous molecule with antinociceptive activity in mice

(-)-3-Isothujone and (+)-3-thujone were examined for antinociceptive activity using the hot-plate and Nilsen tests. In the hot plate test (-)-3-isothujone (ED50 = 6.5 mg/kg) was found to be codeine-like and equipotent with (-)-delta9-tetrahydrocannabinol while the racemic material was essentially half as potent as the levoratatory isomer. (+)-3-Thujone was inactive in both antinociceptive tests as were several structural analogues of the 3-thujones. As with the THC's less antinociceptive activity was observed in the Nilsen test than in the hot-plate assay. Acute toxicities for the 3-thujones were determined and vastly improved synthetic procedures have been developed for two long-known but difficulty accessible 3-thujanols.