[en] Highlights: • Layer-by-layer V_2O_5 structures self-assembly by quadrate sheets like “multilayer cake” were synthesized. • Carbon spheres is as the structure-directing reagent like adhesive to guide the formation of layer-by-layer structures. • UV–vis spectrum shows two major absorption bands at about 340 and 478 nm and PL spectrum exhibits the emission peak at 545 nm for V_2O_5 layer-by-layer structures. • The electrochemical properties of layer-by-layer V_2O_5 structures are significantly improved in organic electrolyte. - Abstract: Layer-by-layer V_2O_5 structures self-assembly by quadrate sheets like “multilayer cake” were successfully synthesized using NH_4VO_3 as the vanadium sources by a facile hydrothermal route and combination of the calcination. The structure and composition were characterized by field emission scanning electron microscopy, energy-dispersive X-ray spectrometer, X-ray powder diffraction, Raman and Fourier transform infrared spectroscopy. The optical properties of the as-obtained V_2O_5 layer-by-layer structures were investigated by the Ultraviolet–visible spectroscopy and photoluminescence spectrum. The electrochemical properties of the as-obtained V_2O_5 layer-by-layer structures as electrodes in supercapacitor device were measured by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) both in the aqueous and organic electrolyte. The specific capacitance is 347 F g"−"1 at 1 A g"−"1 in organic electrolyte, which is improved by 46% compared with 238 F g"−"1 in aqueous electrolyte. During the cycle performance, the specific capacitances of V_2O_5 layer-by-layer structures after 100 cycles are 30% and 82% of the initial discharge capacity in the aqueous and organic electrolyte, respectively, indicating the cycle performance is significantly improved in organic electrolyte. Our results turn out that layer-by-layer V_2O_5 structures are an ideal material for supercapacitor electrode in the present work.

[en] Objective: To investigate the feasibility of ¹H-MR spectroscopy (¹H-MRS) imaging to quantitatively detect fatty liver. Methods: Twenty patients with fatty liver and 11 healthy volunteers underwent plain CT scan, conventional MR imaging and ¹H-MRS analysis. The blood lipid and liver function were tested on the same day as the MR examination. ¹H-MRS sequence measured the peaks of H₂O and lipid, and the areas under the peaks. The relative contents of the lipid compound were calculated, and compared with the results of CT scan and liver function tests. Results: The CT values of the normal group and the fatty liver group were (59 ± 9) HU and (24 ± 11) HU respectively. On ¹H-MRS a protruding high H₂O peak and a flat low lipid peak were observed in the normal group, while the protruding high H₂O peak and a high lipid peak appeared in the fatty liver group. The values of lipid peak in the normal group and the fatty liver group were (0.05 ± 0.01) x l0⁵, (0.70 ± 0.24) x l0⁵ respectively (t=4.32, P<0.05), the values of H20 peak were (1.80 ± 0.52) x l0⁵, (1.85 ± 0.47) x l0⁵ respectively (t=1.26, P>0.05), the areas under the lipid peak were (1.36 ± 0.73) x 10⁹, (2.35 ± 1.15) x 10⁹ respectively (t=5.21, P< 0.05), and the areas under the H₂O peak were (4.33 ± 1.28) x 10¹¹, (3.55 ± 0.94) x 10¹¹ respectively (t=2.04, P>0.05). Conclusion: ¹H-MRS imaging is feasible to quantitatively detect liver fat and is a non-invasive method for detecting early fatty liver. (authors)

[en] Spatial filter is an important device of high energy laser. In order to ensure the above functions, it is necessary to keep a certain vacuum inside the spatial filter. The structure of the existing vacuum maintaining filter is complex and inconvenient to debug. In this paper, a space filter based on titanium pump maintenance is designed by improving the design and process of spatial filter. After testing, the vacuum degree inside the filter can reach 10⁻⁵pa, which can meet the spatial filtering function of high-energy laser beam. (paper)

[en] Highlights: • 3D hierarchical porous N, O-doped carbon was derived by kelp. • 3D hierarchical porous N, O-doped carbon composed of micropores, mesopores and macropores. • 3D hierarchical porous N, O-doped carbon delivered excellent capacitance of 669 mF cm⁻². • The SSC device using 3D carbon delivered an excellent capacitance of 412 mF cm⁻². • The device showed satisfying cyclic stability with the retention of 85% after 10,000 cycles. Three-dimensional (3D) porous N, O-doped carbon with hierarchical structures composed of micropores, mesopores and macropores were synthesized by the direct carbonization of kelp with a “self-activation” process. The as-obtained 3D N, O-doped carbon remained abundant N and O functional groups and the BET specific surface area measured 656 m² g⁻¹. 3D hierarchical porous structures with the pore size ranged from several nanometers to hundred nanometers and lots of pores were attributed to mesopores with the average pore size of about 5.4 nm. Electrochemical properties of the 3D hierarchical porous N, O-doped carbon as a supercapactior (SC) electrode were investigated and it delivered excellent capacitance of 669 mF cm⁻² at 1 mA cm⁻² due to its 3D hierarchical porous structures with high specific surface area which is beneficial for improving ionic storage and transportation in electrodes. This kelp-derived carbon exhibited excellent cyclic performance with the retention of 104% after 10,000 cycles. A flexible solid-state symmetric SC (SSC) device was fabricated using the 3D hierarchical porous N, O-doped carbon and delivered an excellent capacitance of 412 mF cm⁻² at 2 mA cm⁻² and satisfying cyclic stability with the retention of 85% after 10,000 cycles. The areal energy density of the SSC device reach up to 0.146 mWh cm⁻² at the power density of 0.8 mW cm⁻². This facile route for low-cost carbonaceous materials with novel architecture and functionality can be as a promising alternative to synthesize biomass carbon for practical SC application.

[en] The high pressure induced phase transitions in Zn_1-x Cu_x O (x=0.005 and 0.011) are investigated by angle-dispersive synchrotron radiation X-ray diffraction. As the pressure increases, phase transformations from the wurtzite structure to the rocksalt structure are observed in both samples, with the transition pressures at 9.8 GPa and 7.9 GPa, respectively. With the increasing of the Cu-doping concentration in ZnO, crystalline parameters, the bulk moduli, and the Zn-O bond lengths all increased, meanwhile, the transition pressures decreased. The results could be explained in terms of the reduction of phase transformation barriers and the lowering of bond energy. (orig.)

[en] Objective: To evaluate 3.0 T MR DWI techniques in detecting the lesions of pre and post-radiofrequency ablation of the rabbit liver VX2 tumors. Methods: Twenty two New Zealand white rabbits were used in this experiment. Twenty tumor fragments were implanted into the livers of 20 rabbits respectively. Two normal rabbits were used as controls for radiofrequency ablation of the normal liver. 3. 0 T MR DWI was performed 14 to 21 days after tumor implantation (mean, 17 days) in the tumor-bearing animals. Radiofrequency ablation was performed in the 18 tumor-bearing animals and in the two healthy animals. 3.0 T MRI and DWI were performed 7 to 10 days after radiofrequency ablation (mean, 8 days). Pathology was obtained immediately after the completion of post radiofrequency ablation MR imaging. The MRI features and ADC values of pre- and post -radiofrequency ablation lesions in the livers with VX2 tumors and normal rabbits were analyzed and correlation was made with histopathologic findings. Analysis of variance repeated measures were performed in analyzing the differences among the ADC values of different tissues with the same b value. Results: All 20 rabbit liver models of VX2 tumors were constructed successfully. One rabbit died of anesthetic overdose, another one showed necrosis within the implanted tumor. All 18 untreated VX2 tumors had predominantly low or iso-signal intensity on T₁WI and high signal intensity on T₂WI. All 18 VX2 tumors and 2 normal rabbits were treated by radiofrequency ablation successfully. Lesions treated by Radiofrequency ablation displayed low signal intensity on T₁WI, and high signal intensity on T₂WI. Seven to 10 days after radiofrequency ablation, lesions varied from having low signal intensity to slightly increased signal intensity on T₁WI, with areas of mixed (high, intermediate, and low) signal intensity. A peripheral rim of high signal intensity with varying thickness on T₂WI correlated with granulation tissue, which exhibited intense enhancement on contrast-enhanced images. Areas of low to intermediate signal intensity within the lesion on T₂WI corresponded to coagulation necrosis. The tumor tissue appeared as areas of peripheral nodularity, with intermediate to high signal intensity on T₂-weighted images and DWI. The tumor specimen was gray, among the tumor tissue, there were hyperplastic vessels, and granulation tissue. When b value was 600 s/mm², the ADC value of viable tumor (9 cases), necrosis (18 cases), granulation tissue (18 cases), normal liver tissue (18 cases) were (1.227±0.140) × 10^-3, (0.702±0.050) × 10^-3, (1.918±0.124) × 10^-3, (1.739±0.044) × 10^-3 mm²/s, respectively, which were statistically significant (P<0.01). When b=200, 400, 600, 800, 1000 s/mm², the differences of ADC values among viable tumor, granulation tissue, necrosis, normal liver tissue were also statistically significant (P<0.01). Conclusion: The rabbit liver VX2 tumor models and 3.0 T MR DWI are important tools in the basic and clinical researches of radiofrequency ablation. (authors)

[en] Objective: To study the imaging findings of eosinophilic hepatic infiltration on multi- slice spiral CT. Methods: A retrospective analysis was performed to assess the multi-slice spiral CT imaging findings of 10 eases of pathologically confirmed eosinophilic hepatic infiltration. Evaluations were made regarding the lesions' number, site, shape, margin, size, density, enhancement pattern and the relationship between lesions and portal veins. Results: CT demonstrated a single lesion in 2 cases, multiple lesions in 5 and diffuse infiltrative lesions in 3. All lesions were located in subcapsular parenchyma or surrounding the portal vein. Most subcapsular lesions were wedge-shaped, and lesions in the deep parenchyma were irregular. Larger lesions were wedge-shaped or irregular while smaller ones were round or oval. Their size ranged from 4 to 48 mm. On pre-contrast images, these lesions showed slightly low density or isodensity with fuzzy edge. During the arterial phase of post-contrast CT, these lesions exhibited slight enhancement or no enhancement. All lesions were notable and showed relatively low density with homogeneous enhancement and well-defined margin, while centrally heterogeneous enhancement was found in 2 eases during portal venous phase. Isodensity was found in 8 cases during delayed phase, and slightly low density for minor lesions in 2 cases with diffuse lesions. Branches of portal vein was found infiltrated by all lesions, without filling defect or obstruction; low-attenuated stripes surrounding branches of portal vein were found in 3 cases. Conclusion: The multi-slice spiral CT findings of eosinophilic hepatic infiltration are relatively specific, and three-phase dynamic CT studies can be a valuable tool for the diagnosis of this disease. (authors)

[en] Long and straight β-SiC nanowires are synthesized via the direct current arc discharge method with a mixture of silicon, graphite and silicon dioxide as the precursor. Detailed investigations with x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, Raman scattering spectroscopy, transmission electron microscopy and selected area electron diffraction confirm that the β-SiC nanowires, which are about 100-200 nm in stem diameter and 10-20 μm in length, consist of a solid single-crystalline core along the (1 1 1) direction wrapped with an amorphous SiO_x layer. A broad photoluminescence emission peak with a maximum at about 336 nm is observed at room temperature. A direct current arc plasma-assisted self-catalytic vapour-liquid-solid process is proposed as the growth mechanism of the β-SiC nanowires. This synthesis technique is capable of producing SiC nanowires free of metal contamination with a preferential growth direction and a high aspect ratio, without the designed addition of transition metals as catalysts.

[en] ZnO and Cu-doped ZnO nanocrystals have been synthesized by a sol-gel method. The nanocrystals have been investigated by XRD and all the particles are found to show the wurtzite structure. X-ray photoelectron spectroscopy and Raman scattering results provide evidence that Cu ions are mainly in the divalent state and incorporated into the ZnO lattice at Zn²⁺ sites. Magnetic measurements reveal that the as-grown Zn_0.9894Cu_0.0106O nanocrystals exhibit room temperature ferromagnetic behaviour with the saturation magnetization of 0.0053 emu g^-1 and the Curie temperature above 300 K.

[en] Highlights: → Zn nanowires synthesized through DC arc discharge. → ZnO and C as precursors without any template or catalyst. → Zn nanowires with diameters 50-100 nm and lengths several micrometers. → Rapidity, low cost, large quantity and no pollution compared to other methods. - Abstract: We demonstrate the growth of Zn nanowires by using a mixture of ZnO and C as precursors via direct current arc discharge method without the addition of any catalyst or template. This simple practical procedure is capable of producing Zn nanowires in large quantities without reoxidation. The Zn nanowires usually have serpentine geometries, with lengths up to a few micrometers and diameters 50-100 nm. The selected area electron diffraction pattern and high-resolution transmission electron microscopy image demonstrate perfect crystallinity with the growth direction of [0 0 1]. The growth mechanism of the Zn nanowires can be considered as plasma-assisted vapor-solid mechanism.