An experimental study on the effect of hexagonal boron nitride (h‐BN) underlay and cap layers on excitonic dynamics in monolayer WS2 is reported. A monolayer WS2 flake is fabricated by mechanical exfoliation. By using a dry transfer technique, three regions of the sample are obtained: WS2 directly on SiO2, WS2 on h‐BN, and WS2 sandwiched by two h‐BN flakes. Photoluminescence measurements show higher yield and narrower linewidth of the h‐BN/WS2/h‐BN region. Transient absorption measurements reveal that the top h‐BN layer enhances the exciton formation, prolongs the exciton lifetime, and slightly affects the exciton–exciton annihilation. By performing spatially resolved transient absorption measurements, exciton diffusion coefficients of about 100, 40, and 26 cm2 s−1 for the regions of WS2, h‐BN/WS2, and h‐BN/WS2/h‐BN, respectively, are obtained. The suppression of exciton diffusion by h‐BN is attributed to the additional phonon scattering mechanisms introduced by h‐BN, which decreases the exciton mean free path and thus the diffusion coefficient. The findings provide useful information for designing and understanding the effect of h‐BN layers interfacing with 2D semiconductors.

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Aim: To compare thermocoagulation and cryotherapy for treatment of high-grade cervical intraepithelial neoplasia (CIN). Methods: From May 2017 to May 2018, women with CIN2/3 were randomized to thermocoagulation or cryotherapy at Peking University Shenzhen Hospital. Follow-up at 4 and 8 months included cytology and human papillomavirus (HPV) testing. Women who were HPV-positive or had atypical squamous cells of undetermined significance or higher-grade disease underwent colposcopy/biopsy. Results: Among 149 women enrolled, 74 were randomized to thermocoagulation, and 75 to cryotherapy (excluded four were immediately referred for thermocoagulation due to large lesions). At follow-up, there was no difference between the thermocoagulation and cryotherapy groups in HPV-negative (4/8 months: 72.5%/86.2% vs 68.6%/80.6%) and pathology-negative (97.1%/98.5% vs 94.3%/92.3%) rates (all P > 0.05). The cytology-negative rate was similar for thermocoagulation and cryotherapy at 4 months (79.7% vs 78.9%, P > 0.05), but higher for thermocoagulation at 8 months (100% vs 88.7%, P < 0.05). No lesions were observed among the four referral women at follow-up. As compared with cryotherapy, thermocoagulation was associated with shorter duration of treatment and less vaginal discharge, but higher pain during application and longer bleeding after treatment. Conclusion: Thermocoagulation was as effective and safe as cryotherapy and might be easily applied to treat high-grade cervical lesions.

PRV measurement could present the similar results as HRV analysis for sleep apnea patients during different sleep stages.

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