Superfluid Onset and Compressibility of 4^4He Films Adsorbed on Carbon Nanotubes

Third sound measurements of superfluid $^4$He thin films adsorbed on 10 nm diameter multiwall carbon nanotubes are used to probe the superfluid onset temperature as a function of the film thickness, and to study the temperature dependence of the film compressibility. The nanotubes provide a highly ordered carbon surface, with layer-by-layer growth of the adsorbed film as shown by oscillation peaks in the third sound velocity at the completion of the third, fourth, and fifth atomic layers, arising from oscillations in the compressibility. In temperature sweeps the third sound velocity at very low temperatures is found to be linear with temperature, but oscillating between positive and negative slope depending on the film thickness. Analysis shows that this can be attributed to a linearly decreasing compressibility of the film with temperature that appears to hold even near zero temperature. The superfluid onset temperature is found to be linear in the film thickness, as predicted by the Kosterlitz-Thouless theory, but the slope is anomalous, a factor of three smaller than the predicted universal value.Comment: 6 pages, 4 figures, revised version published in PR

Research on Subsurface Damage Measurement of Fused Silica in Ultra-Precision Grinding Based on Laser Damage Performance

In order to achieve accurate prediction of subsurface damage (SSD) in ultra-precision grinding of high-performance ultra-violet laser-irradiated fused silica optics, the paper combines damage precursor multimodal measurement technology with magnetorheological finishing spot method detection. Various methods such as photothermal weak absorption and fluorescence confocal imaging are used for measuring the surface roughness and subsurface damage depth of a series of fused silica samples prepared under different ultra-precision grinding parameters. The correlation between surface roughness and subsurface damage depth in ultra-precision grinding based on laser damage performance is established using curve fitting. The results indicate that there is a metamorphic layer below the subsurface crack layer, which can cause additional photothermal absorption. Subsurface damage is constituted of the subsurface crack layer and metamorphic layer. Under ultra-precision grinding conditions, the maximum depth of subsurface damage is generally 2.00–4.22 times the depth of the subsurface damage cluster. The roughness Ra and the subsurface damage cluster depth correspond to SSD(cluster) = 195 × Ra − 0.13. The maximum depth of subsurface damage can be predicted by measuring the Ra value, by which accurate prediction of defect depth in ultra-precision grinding and guiding the high-performance manufacturing of ultra-violet laser-irradiated fused silica optics can be achieved

Development and validation of a prognostic nomogram for predicting cancer-specific survival in advanced endometrial carcinoma after surgery: a retrospective analysis of the SEER Database

Objective We aimed to construct and validate a prognostic nomogram to predict cancer-specific survival (CSS) after surgery in patients with advanced endometrial carcinoma (EC).Design Retrospective cohort study.Setting and participants The Surveillance, Epidemiology, and End Results (SEER) Database contains cancer incidence and survival data from population-based cancer registries in the USA. A total of 5445 patients from the SEER Database diagnosed with advanced EC between 2004 and 2015 were included and randomised 7:3 into a training cohort (n=3812) and a validation cohort (n=1633).Outcome measure CSS.Results The nomograms for CSS included 10 variables (positive regional nodes, age, tumour size, International Federation of Gynecology and Obstetrics (FIGO) stage, grade, ethnicity, income, radiation, chemotherapy and historical stage) based on the forward stepwise regression results. They revealed discrimination and calibration using the concordance index (C-index) and area under the time-dependent receiver operating characteristic curve, with a C-index value of 0.7324 (95% CI=0.7181 to 0.7468) and 0.7511 (95% CI=0.7301 to 0.7722) for the training and validation cohorts, respectively. Using calibration plots, a high degree of conformance was shown between the predicted and observed results. Additionally, a comparison of the nomogram and FIGO staging based on changes in the C-index, net reclassification index and integrated discrimination improvement demonstrated that the nomogram had better accuracy and efficacy.Conclusions We successfully constructed an accurate and effective nomogram to predict CSS in patients with advanced EC, which may help clinicians determine optimal individualised treatment strategies for patients with advanced EC. The predictive performance of the nomogram was evaluated thoroughly, but only internally. Therefore, further validation using different data sources is warranted in future related studies