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[en] In the framework of a modified Fisher model, the ratio of the symmetry-energy coefficient to temperature (asym/T) is extracted from the fragment produced in the 124,136Xe induced reactions using the isobaric yield ratio methods based on different approximations. It is found that for nuclei with the same neutron excess (I≡N-Z) increases when the mass of the fragment increases, while for isobar asym/T decreases when I increases. It is also found that the extracted asym/T of the nucleus has very little dependence on the n/p ratio of the projectile, target, and the incident energies in the reaction. (orig.)
[en] Highlights: • Mode 4 has the highest exergy efficiency. • Mode 2 has the largest exergy density. • Second heat exchanger has the largest exergy destruction. - Abstract: Advanced adiabatic compressed air energy storage system plays an important role in smoothing out the fluctuated power from renewable energy. Under different operation modes of charge-discharge process, thermodynamic behavior of system will vary. In order to optimize system performance, four operation modes of charge-discharge process are proposed in this paper. The performance difference of four modes is compared with each other based on energy analysis and exergy analysis. The results show that exergy efficiency of mode 4 is the highest, 55.71%, and exergy density of mode 2 is the largest, 8.09 × 106 J m−3, when design parameters of system are identical. The second heat exchanger has the most improvement potential in elevating system performance. In addition, a parametric analysis and multi-objective optimization are also carried out to assess the effects of several key parameters on system performance.
[en] Objective: To evaluate the predictive value of 18F-fluorodeoxyglucose (FDG) and 18F-fluorothymidine (FLT) PET in monitoring the metastatic potential of human colorectal cancer (CRC). Methods: Human CRC cell lines SW480 and SW620 were cultured and implanted into nude mice to create CRC models. Tumor growth, metastatic status and survival were assessed in CRC bearing mice. Uptake of 18F-FDG and 18F-FLT in SW480 and SW620 cells was detected In vitro at 0, 30, 60, 90, 120 min after incubation. PET images of both tracers were acquired for SW480 and SW620 tumor-bearing mice using the small animal PET at 60 min after tracer injection. Region of interest (ROI) was drawn using Image J software on reconstructed PET images. Immunocytochemistry and Western blot analysis of the tumor tissue were performed. The correlation between tracer uptake and tumor marker expression was evaluated using linear regression. Results: Compared with SW620 tumor-bearing mice, SW480 induced tumor grew much faster (t = - 3.332, P = 0.004), the tumor-bearing mice had more serious dyscrasias (t = 2.240, P = 0.038 ), shorter survival and higher metastatic rate. In vitro study, the uptake of both 18F-FDG and 18F-FLT in SW620 cells was lower than that in SW480 cells. 18F-FLT uptake was higher than 18F-FDG uptake in both SW480 and SW620 cells. After incubation for 60 min,the uptake of 18F-FDG in SW480 and SW620 cells was (1.76 ± 0.87)% and ( 1.14 ± 0.38 )%, respectively (t = -2.507, P = 0.021); while the uptake of 18F-FLT in SW480 and SW620 cells was (5.21 ± 1.60)% and (2.90 ± 1.82)%, respectively (t =3.497, P =0.002). In micro-PET study, the 18F-FDG radioactivity ratio of tumor to non-tumor (T/NT) in SW480 and SW620 tumors was 2.69 ± 0.98 and 3.09 ± 1.26 respectively (t =0.657, P =0.524); while T/NT of 18F-FLT in SW480 and SW620 tumors was 3.65 ±0.51 and 2.22 ±0.42 (t =6.491, P <0.001), respectively. In immunocytochemistry and western blot assay, heat shock protein(HSP) 27, Integrin β3, vascular endothelial growth factor receptor 2 (VEGFR2) and Ki67 were all over expressed in two kinds of tumor cells with different intensities. HSP27 and Integrin β3 expression was higher in SW480 cells than that in SW620 cells. While VEGFR and Ki67 expression was lower in SW480 cells than that in SW620 cells. The uptake of 18F-FLT closely correlated with the expression of HSP27 (r =0.924, P =0.004) and Integrin β3 (r=0.813, P =0.025). 18F-FDG uptake inversely correlated with the survival of tumor-bearing mice (r =0.500, P=0.017). Conclusions: The uptake of 18F-FDG and 18F-FLT may reflect different biological characteristics of CRC. High 18F-FLT uptake in CRC on PET scan may predict high metastatic tendency. (authors)
[en] Objective: To evaluate whether 18F-fluorothymidine (FLT) can be used to monitor early response to irradiation in colorectal cancer (CRC). Methods: SW480 cells were cultured and irradiated with 0, 10, and 20 Gy. Twenty-four hours later, morphological changes, apoptosis, necrosis, proliferation, and cell cycle phases were observed. Uptake of 18F-FLT was measured in these tumors in vitro from 24 h to 72 h after irradiation. The one-way analysis of variance was used to analyze the data. Results: Apoptotic and necrotic cells were detected 24 h after radiotherapy. SW480 cells proliferation was significantly delayed after irradiation in 3- (4, 5-dimethylthiazol-2-yl) -2, 5-diphenylte-trazolium bromide (MTT) assay. Cell cycle analysis showed that SW480 cells had a decreased fraction of cells in S phase (from 33.23% to 9.24%, then to 5.43%) and an arrested fraction in G0-G1. After SW480 cells were cultured for 60 min, the uptake of 18F-FLT was (5.21±1.60)%; and 24 h after irradiation of 10 Gy, the uptake decreased significantly to (4.27±0.48)% (F=8.253, P=0.009). And 72 h after irradiation, the uptake further decreased significantly to (3.39±0.59)% (F=36.715, P<0.001). In tumor tissue, the uptake of 18F-FLT reduced significantly 72 h after radiotherapy (10 Gy: F=12.388, P=0.007; 20 Gy: F=16.744, P=0.004) and the attenuation degree increased with the radiation dose. Conclusion: The uptake of 18F-FLT in SW480 cells or in CRC could reflect the changes of SW480 cells in proliferation, cell cycle re-distribution, cell apoptosis and necrosis. The results suggest that 18F-FLT may used for monitoring early response to irradiation of CRC. (authors)
[en] Under a large signal drive level, a frequency domain black box model of the nonlinear scattering function is introduced into power FETs and diodes. A time domain measurement system and a calibration method based on a digital oscilloscope are designed to extract the nonlinear scattering function of semiconductor devices. The extracted models can reflect the real electrical performance of semiconductor devices and propose a new large-signal model to the design of microwave semiconductor circuits.
[en] Based on the closed-orbit theory, the magnetic field effect in the photodetachment of negative ion in the electric field near a metal surface is studied for the first time. The results show that the magnetic field can produce a significant effect on the photodetachment of negative ion near a metal surface. Besides the closed orbits previously found by Du et al. for the H− in the electric field near a metal surface (J. Phys. B 43 035002 (2010)), some additional closed orbits are produced due to the effect of magnetic field. For a given ion—surface distance and an electric field strength, the cross section depends sensitively on the magnetic field strength. As the magnetic field strength is very small, its influence can be neglected. With the increase of the magnetic field strength, the number of the closed orbits increases greatly and the oscillation in the cross section becomes much more complex. Therefore we can control the photodetachment cross section of the negative ion by changing the magnetic field strength. We hope that our results may guide future experimental studies for the photodetachment process of negative ion in the presence of external fields and surfaces. (atomic and molecular physics)
[en] Highlights: • A chemical bath deposition method was used for synthesis of CdS/BiOI composite. • The removal rate of EE2 over CdS/BiOI composite could approach 100% after 12 min under visible light irradiation. • The Z-scheme mechanism of EE2 degradation by CdS/BiOI was proposed. - Abstract: A novel CdS/BiOI composite has been prepared via a chemical bath deposition method. The physical and chemical properties of as-prepared composites were characterized by XRD, SEM, TEM, EDS, XPS, UV–vis DRS, and PL. The synthesized CdS/BiOI composites exhibited superior photocatalytic activity in photodegrading of 17α-ethinyl estradiol (EE2) compared to pure CdS and pure BiOI, and the removal rate of EE2 could approach 100% after only 12 min of visible light irradiation using 3:1 CdS/BiOI composite as photocatalyst. The reaction rate constant over 3:1 CdS/BiOI composite was 6.3, 7.1 and 70.9 times higher than that of pure CdS, pure BiOI and P25 respectively. In addition, a Z-scheme charge separation mechanism was proposed on the basis of the experimental results and the theoretical calculation. Moreover, the prepared composite showed good stability and recyclability which are beneficial for its practical application.
[en] The iron-based superconductivity (IBSC) is a great challenge in correlated system. Angle-resolved photoemission spectroscopy (ARPES) provides electronic structure of the IBSCs, the pairing strength, and the order parameter symmetry. Here, we briefly review the recent progress in IBSCs and focus on the results from ARPES. The ARPES study shows the electronic structure of “122”, “111”, “11”, and “122*” families of IBSCs. It has been agreed that the IBSCs are unconventional superconductors in strong coupling region. The order parameter symmetry basically follows s± form with considerable out-of-plane contribution. (topical review - iron-based high temperature superconductors)
[en] This paper reports a cylindrical shear-mode magnetoelectric (ME) composite developed based on a Pb(Zr,Ti)O3 (PZT) tube bonded with an NdFeB permanent magnet for magnetic coupling. The existence of a significant ME effect originating from the superior d15 electromechanical response of the piezoelectric phase is theoretically predicted and experimentally observed with a voltage coefficient of 28.8 mV/Oe (RMS) outside resonance and a maximum power density of 4.56 μW (cm3·Oe2)−1 at resonance, which are much higher than previous shear-mode ME composites without bias field in the literature. These suggest broad application prospects of this particular ME composite as magnetic sensors, transducers and energy harvesters. (paper)
[en] Magnetic properties of Fe3O4 and magnetic tunnel junctions with Fe3O4 bottom electrode have been investigated. Highly conductive V/Ru layers were used as an underlayer of the Fe3O4 films. The V/Ru/Fe3O4 on  out-of-plane oriented MgO single crystal substrate show an anisotropy and high squareness along [11(bar sign)0] direction, while the Fe3O4 films with an underlayer of just Ru show isotropic behavior and low squareness. X-ray diffraction shows tensile stress on Fe3O4 for V/Ru/Fe3O4 samples. The anisotropy was shown to be induced by the stress. Finally, magnetic tunnel junction stacks of MgO/V/Ru/Fe3O4/AlO/CoFe/NiFe/Ru were deposited and the magnetic tunnel junctions with a junction size ranging from 2x2 μm2 to 9x9 μm2 were fabricated by optical lithography. The junctions show magnetoresistance ratios of ∼14% and no geometrical effect due to the junction size