CR–39(DOP) kao detektor relativističkih iona 238U

CR-39(DOP) stack was exposed to 927 MeV/n 238 92 U beam from the Lawrence Berkeley Laboratory (LBL) accelerator BEVALAC at an angle of 30o to the detector surface. The chemically processed sheets were investigated using a Leitz Ortholux optical microscope. 644 etch pit cone lengths were measured and the track etch rate has been found to be (174 ± 11) µm/h. The present result is in accord with the data of Heyna et al. The estimated charge sensitivity has been found to follow the extrapolated results of Salamon et al. The present survey on the etch rate ratio has been found to increase faster than exponentially with Z/β and follows the relation VT /VG = exp[A + B(Z/β − 60) + C(Z/β − 60)2 ] where A = 1.623 ± 0.064, B = −0.0444± 0.0015 and C = 0.000506 ± 0.000064 for 27.6 ≤ Z/β ≤ 106.4.Slog CR–39(DOP) listova bio je izložen snopu iona 238 92 U energije 927 MeV/nukleon u akceleratoru BEVALAC, u Lawrence Berkeley laboratoriju, pod kutom od 30◦ prema površini tih detektorskih listova. Listovi su kemijski obradeni i ispitani pomoću optičkog mikroskopa Leitz Ortholux. Premjereno je 644 koničnih rupica nastalih prolaskom iona, i određena je brzina jetkanja oko tragova iona od (174±11) µm/h. Ovi su rezultati u skladu s rezultatima Heina i suradnika. Ocjenjena nabojna osjetljivost je u skladu s ekstrapoliranim rezultatima Salamonova i suradnika. Utvrđeno je da brzina jetkanja raste brže nego eksponencijalno o Z/β, i može se opisati relacijom VT /VG = exp(A + B(Z/β − 60) + C(Z/β − 60)2 ), gdje je A = 1.623 ± 0.064, B = −0.0444 ± 0.0015 i C = 0.000506 ± 0.000064, za 27.6 ≤ Z/β ≤ 106.4

Microscopic model for the strain-driven direct to indirect band-gap transition in monolayer MoS₂ and ZnO

At the monolayer limit both MoS2 and the graphitic phase of ZnO have a direct band gap. Biaxial tensile strain has been found to induce a transition into an indirect band-gap semiconductor with the strain percentage required for the transition equal to 0.83% for MoS2 and 8% for ZnO, respectively. A low strain percentage is desirable for possible device applications. We identify a simple design principle which could be used to identify materials requiring a small strain to induce such a transition. A scaling of the hopping interaction strengths according to Harrison's law within a tight-binding model for MoS2 is able to capture the effect