[en] In contrast with entanglement and quantum discord (QD), we investigate the thermal quantum correlation in terms of Schatten one-norm geometric quantum discord (GQD) in the XY spin chain, and analyze their capabilities in detecting the critical point of quantum phase transition. We show that the one-norm GQD can reveal more properties about quantum correlation between two spins, especially for the long-range quantum correlation at finite temperature. Under the influences of site distance, anisotropy and temperature, one-norm GQD and its first derivative make it possible to detect the critical point efficiently for a general XY spin chain. - Highlights: • Comparing with entanglement and QD, one-norm GQD is more robust versus the temperature. • One-norm GQD is more efficient in characterization of long-range quantum correlation between two distant qubits. • One-norm GQD performs well in highlighting the critical point of QPT at zero or low finite temperature. • One-norm GQD has a number of advantages over QD in detecting the critical point of the spin chain.

[en] Objective: To explore the imaging features and diagnostic value of ¹⁸F-FDG PET/CT in pulmonary lymphangitic carcinomatosis (PLC). Methods: Retrospective analysis on 53 PLC cases was performed. The patients underwent PET/CT + thin breath hold CT scanning. The PET images were attenuated by CT scanning data and reconstructed by TrueX + time of flight method. The mean standardized uptake value (SUVmean) of each region of interest was measured, and the standardized uptake ratios (SUR) value was calculated. The difference of the SUVmean and SUR values in different regions was compared. Results: Among the 53 patients with PLC, 51 (96%, 51/53) displayed interlobular septal thickening of the interlobular septa with radioactive uptake, and the lung SUVmean was significantly higher than that of the normal lung field (1.46 ± 0.92 vs. 0.58 ± 0.18, t = 19.85, P < 0.01). The interlobular septal thickening lung/mediastinal blood pool SUR was higher than that of the normal septal lung/mediastinal blood pool SUR (0.84 ± 0.38 vs. 0.40 ± 0.21, t = 12.77, P < 0.01), and 51 cases (96%, 51/53) manifested bronchovascular bundle uptake enhancement. The SUVmean of PLC involving bronchovascular bundle was significantly higher than that of normal bronchovascular bundle (3.85 ± 1.67 vs. 0.90 ± 0.19, t = 15.45, P < 0.01). The SUR of the thickened bronchi vascular bundle/mediastinal blood pool was higher than that of the normal bronchovascular bundle/mediastinal blood pool SUR (2.89 ± 0.94 vs. 0.59 ± 0.19, t = 12.62, P < 0.01). In 51 cases (96%, 51/53), the swelling of the hilum and mediastinal lymph nodes was enhanced with radioactivity. Conclusions: PET/CT fusion imaging of typical patients with PLC is characterized by the thickening of bronchial vascular bundles with radioactive concentration and thickening of the interlobular septal nodules with increased uptake of radioactivity. Moreover, the hilar and mediastinal lymph nodes were enlarged or normal with abnormal concentration of radioactivity. PET/CT fusion imaging combined with local SUVmean and SUR can measurements not only enables the early and accurate diagnosis of PLC lesions. (authors)

[en] In this research, the performance of the Sine-Transform reconstruction algorithm was analyzed and compared with the existing reconstruction algorithms using Fourier Transform techniques. The parameters considered in the study were the time-of-flight resolution, the finite intrinsic detector resolution and the resolution of data array. Standard images such as uniform distribution, annular distribution and others were used in the theoretical analysis for comparison purposes. The statistical model for time-of-flight uncertainty published in [1] was modified to include the effect of finite intrinsic detector resolution. Preliminary results indicated the performance of this Sine-Transform reconstruction algorithm is comparable to that of the existing Fourier Transform based reconstruction algorithms. Reconstruction examples using computer simulated TOFPET data provided visual inspection of the quality of images reconstructed by Sine-Transform algorithm

[en] The temperature dependence of the radiative recombination zone in InGaN/GaN multiple quantum well light-emitting diodes is investigated. >From the electroluminescence spectra measured at various temperatures, it is found that there are two peaks at about 400 and 460 nm, which can be assigned as Mg-related and quantum well transitions, respectively. The behavior of these two peaks with temperature is modeled by the two rate equation. Based on this model, we deduce the activation energy of Mg in GaN films to be about 126 meV, which is consistent with reported results obtained by other techniques. [copyright] 2001 American Institute of Physics

[en] Objective: To assess the clinical value of C-arm CT in sacral tumor embolization. Methods: From 2016 through 2019, 62 patients with sacral tumors underwent interventional therapy. All patients had pathologically confirmed diagnosis of giant cell tumors (40 primary, 7 recurrent), chordomas (5), hemangiomas (2), Ewing's sarcoma (1), and aneurysmal bone cysts (7) of the sacrum. Contrast-enhanced multi-slice CT (MSCT) was performed on all patients including C-arm CT examination (43) before interventional therapy. The image quality with and without C-arm CT were compared qualitatively. Independent sample t test was used to compare the total X-ray radiation dose and bleeding during post-operative follow-up. Results: The treatment plans of 31 patients were adjusted according to C-arm CT examination. The image quality of C-arm CT was inferior to that of MSCT. All patients had varying degrees of artifacts on C-arm CT images with little influence on diagnosis. The average radiation dose in the C-arm CT group (825.3 ± 448.0 mGy) was significantly lower (P < 0.01) than that of the group without C-arm CT (1620.6 ± 767.4 mGy). In 37 patients with preoperative arterial embolization, the follow-up surgery was successful in all patients without complications related to interventional therapy such as wound non-union. The average blood loss in C-arm CT group (1943 ± 2131 mL) was not significantly lower (P = 0.34) than that of non-C-arm CT group (2560 ± 1648 ml). Conclusion: In the interventional treatment of sacral tumors, C-arm CT can accurately determine the vascular supply for pre-operative embolization, facilitate surgery, and reduce the radiation exposure. (authors)

[en] The Kerr intensity versus the Ag thickness for Ag grown on the top of Co/Ir(111) exhibits an oscillating behavior with a period around one monolayer which should be due to the morphological change related electronic structure differences of the Ag layer. From systematical investigations of Ag/Co/Ir(111) films with the Co layer thinner than 4 monolayers at temperatures below 900 K, a magnetic phase diagram has been established. As the annealing temperature increases for Ag/Co/Ir(111) films, enhancements of the coercive force occur in both the polar and longitudinal configurations due to the intermixing of Ag and Co at the interface and the formation of Co–Ir alloy. The disappearance of ferromagnetism is mainly attributed to the reduced atomic percent of cobalt in Co–Ir alloy, the lowered Curie temperature by a reduction of the thickness of magnetic layers, and the intermixing of Ag and Co at the Ag/Co interface. - Highlights: • An oscillating behavior occurs due to the morphological change for Ag on Co/Ir(111). • A magnetic phase diagram has been established for Ag/Co/Ir(111). • Some Ag atoms intermix with the underlying Co layer at high temperatures. • Polar coercive force is enhanced due to the compositional change

[en] The results of the performance of a new type semiconductor detector personal dosimeter, SDM2000 personal dosimeter, made by China Institute for Radiation Protection is presented. Some calibration researches were performed on radiological performance of the dosimeter including radiation energy, incidence angular, beta radiation, neutrons radiation, accuracy of alarm levels, relative intrinsic error, overload, time response, linearity and retention of reading. There are also tests on the effects of a variety of environmental conditions, such as temperature, humidity, external electromagnetic fields and electrostatic discharge. Other characteristics for dropping, vibration and battery life were also tested

[en] Conventional studies of biomolecular behaviors rely largely on the construction of kinetic schemes. Since the selection of these networks is not unique, a concern is raised whether and under which conditions hierarchical schemes can reveal the same experimentally measured fluctuating behaviors and unique fluctuation related physical properties. To clarify these questions, we introduce stochasticity into the traditional lumping analysis, generalize it from rate equations to chemical master equations and stochastic differential equations, and extract the fluctuation relations between kinetically and thermodynamically equivalent networks under intrinsic and extrinsic noises. The results provide a theoretical basis for the legitimate use of low-dimensional models in the studies of macromolecular fluctuations and, more generally, for exploring stochastic features in different levels of contracted networks in chemical and biological kinetic systems

[en] Highlights: • A 3D CFD model takes in transmembrane heat and mass transfer developed. • DCMD modules using spacer-filled and empty channels for desalination simulated. • Fluid flow, heat transfer and mass transfer profiles revealed. • Correlations of friction factor and Nusselt number developed. - Abstract: Membrane distillation (MD) is an emerging and promising membrane separation process, which can directly utilize renewable thermal energy or low-grade waste heat, for applications in water or wastewater treatment and food industry. However, a major drawback of MD process is its low energy efficiency. Spacer is the most suggested and studied eddy promoter to enhance the heat and mass transfer, which further improves both the separation and the energy utilization performance, of MD processes. This paper presents the results of a 3D computational fluid dynamics (CFD) simulation of DCMD (direct contact membrane distillation) modules using channels with and without spacers for desalination application. The model employs permeable wall boundary condition to take into account the transmembrane heat and mass transfer and simulates the entire module length. The simulation reveals similar fluctuating distributions of temperature polarization coefficient, transmembrane heat and mass fluxes as well as the shear stress on the membrane surface along the entire module length. Correlations have been developed for friction factor and average Nusselt number. These correlations are useful for the analysis and design of DCMD modules. The extent of heat transfer enhancement by spacers depends on the geometry of spacers and the Reynolds number of fluid.

[en] A cesium telluride (Cs₂Te) photocathode with a quantum efficiency of 13% at 253.7 nm (radiant incidence 200 μW/cm²) is fabricated by tellurium and cesium vapor deposition onto a stainless-steel substrate., The cesium telluride cathode will be used to provide a high-brightness electron beam source for the 3+1/2 photo-injector at Peking University. The design of the system, the fabrication procedures and the preliminary experimental results are presented in this paper. (authors)