The formation of high-quality thin films of polytetrafluoroethylene (PTFE) is important in many applications ranging from material reinforcement to molecular electronics. Laser ablation, a technique widely used to deposit a variety of inorganic materials, can also be used as a simple and highly versatile method for forming thin polymer films. The data presented show that PTFE films can be produced on various supports by the evaporation of a solid PTFE target with a pulsed ultraviolet laser. The composition of the ablation plume suggests that PTFE ablation and subsequent film formation occur by way of a laser-induced pyrolitic decomposition with subsequent repolymerization. The polymer films produced by this method are composed of amorphous and highly crystalline regions, the latter being predominantly in a chain-folded configuration with the molecular axis aligned parallel to the substrate surface.

The structure and stability of thin tungsten films prepared by radio frequency magnetron sputter deposition have been studied by x-ray diffraction and x-ray photoelectron spectroscopy. The structure of these films has been found to systematically evolve from the metastable A15 β-W phase to the equilibrium A2 α-W phase with decreasing oxygen impurity concentration. Within the β-W phase a decrease in the concentration of incorporated oxygen results in a monotonic decrease in the lattice parameter of the unit cell until the β-W phase eventually becomes unstable, and the α-W phase is formed.

The effects of surface oxidation on the structural and magnetic properties of fine Fe particles prepared by the evaporation technique have been studied using transmission electron microscopy, x-ray photoelectron spectroscopy, superconducting quantum interference device magnetometry, and Mossbauer spectroscopy. By varying the argon pressure, particles were obtained with sizes in the range of 60-350 A. The hysteresis behavior was found to be strongly dependent on the variation in the amount of surface oxidation. The differences in the magnetic behavior due to variation in size and oxidation have been explained by considering a shell/core model for the particle morphology with the shell consisting of Fe oxides surrounding the a-Fe core.

Co-doped TiO 2 nanoparticles containing 0.0085, 0.017, 0.0255, 0.034, and 0.085 mol % Co(III) ion dopant were synthesized via sol-gel and dip-coating techniques. The effects of metal ion doping on the transformation of anatase to the rutile phase have been investigated. Several analytical tools, such as X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray analysis (EDAX) were used to investigate the nanoparticle structure, size distribution, and composition. Results obtained revealed that the rutile to anatase concentration ratio increases with increase of the cobalt dopant concentration and annealing temperature. The typical composition of Co-doped TiO 2 was Ti 1−x Co x O 2 , where x values ranged from 0.0085 to 0.085. The activation energy for the phase transformation from anatase to rutile was measured to be 229, 222, 211, and 195 kJ/mole for 0.0085, 0.017, 0.0255, and 0.034 mol % Co in TiO 2 , respectively.

Purpose To evaluate the impact of the COVID-19 pandemic on Canadian intensive care unit (ICU) workers. Methods Between June and August 2020, we distributed a cross-sectional online survey of ICU workers evaluating the impact of the pandemic, coping strategies, symptoms of post-traumatic stress disorder (PTSD; Impact of Events Scale-Revised), and psychological distress, anxiety, and depression (Kessler Psychological Distress Scale). We performed regression analyses to determine the predictors of psychological symptoms. Results We analyzed responses from 455 ICU workers (80% women; 67% from Ontario; 279 nurses, 69 physicians, and 107 other healthcare professionals). Respondents felt that their job put them at great risk of exposure (60%), were concerned about transmitting COVID-19 to family members (76%), felt more stressed at work (67%), and considered leaving their job (37%). Overall, 25% had probable PTSD and 18% had minimal or greater psychological distress. Nurses were more likely to report PTSD symptoms (33%) and psychological distress (23%) than physicians (5% for both) and other health disciplines professionals (19% and 14%). Variables associated with PTSD and psychological distress included female sex (beta-coefficient [B], 1.59; 95% confidence interval [CI], 1.20 to 2.10 and B, 3.79; 95% CI, 1.79 to 5.78, respectively; P < 0.001 for differences in scores across groups) and perceived increased risk due to PPE shortage or inadequate PPE training (B, 1.87; 95% CI, 1.51 to 2.31 and B, 4.88; 95% CI, 3.34 to 6.43, respectively). Coping strategies included talking to friends/family/colleagues (80%), learning about COVID-19 (78%), and physical exercise (68%). Over half endorsed the following workplace strategies as valuable: hospital-provided scrubs, clear communication and protocols by hospitals, knowing their voice is heard, subsidized parking, and gestures of appreciation from leadership. Conclusions This survey study shows that ICU workers have been impacted by the COVID-19 pandemic with high levels of stress and psychological burden. Respondents endorsed communication, protocols, and appreciation from leadership as helpful mitigating strategies. Supplementary Information The online version contains supplementary material available at 10.1007/s12630-021-02175-z.

Pt/Co multilayers are an attractive candidate for a magneto-optical recording medium. However, films sputter deposited in Ar have coercivities too small (100–350 Oe) to be practical in recording. By sputter depositing multilayers in Kr or Xe instead of Ar, we achieved coercivities ∼1000 Oe, suitable for recording. We attribute the lower coercivity of Ar-sputtered films to interfacial mixing of Pt and Co layers by energetic bombardment from Ar gas atoms that recoil from the Pt target.

Metastable Ge 1Ϫy C y alloys were grown by molecular beam epitaxy as homogeneous solid solutions having a diamond lattice structure. The substrates were ͑100͒ oriented Si wafers and the growth temperature was 600°C. We report on measurements of the composition, structure, lattice constant, and optical absorption of the alloy layers. In thick relaxed layers, C atomic fractions up to 0.03 were obtained with a corresponding band gap of 0.875 eV. These alloys offer new opportunities for fundamental studies, and for the development of silicon-based heterostructure devices.

Films of polytetrafluoroethylene (PTFE) were deposited by laser ablation using the fourth harmonic, at 266 nm, of a Nd-YAG laser. The films are found to be stoichiometric with the correct optical properties. We suggest that UV absorption onsets the pyrolitic decomposition of PTFE leading to a monomer that subsequently repolymerizes onto a substrate.