[en] Type of phases and feature on corrosion surface and changes of composition and microstructure on cross section of type 316Ti and 321 austenitic stainless steels exposed to sodium at 650degC for 4000, 5000, 8000, 10000 hrs are examined by optical microscope, scanning electromicroscope, Auger spectrum instrument and X-ray diffractometer. The effect of mass transfer on the steels is obvious in the flowing sodium, carbon diffuses from the flowing sodium to the steels and nickel and chromium diffuse from the steels to the flowing sodium, it causes the changes of composition, type of phases and microstructure and decreasing corrosion resistance of the steels. (author)

[en] The effect of laser fields on the NO interaction potentials is obtained by the calculation of time-resolved photoelectron spectrum (TRPES) using the time-dependent wave-packet method. The calculation not only shows that the overlap of the pump-probe pulses makes some NO molecular 'invisible' states visible, but also that the coupling strength and the positions of relevant curves change on increasing the laser intensity. These changed potentials affect their dynamical behavior and influence the shape and position of each peak in TRPES. That the coupling strength of relevant potentials can be changed by the field-matter interaction is consistent with our ab initio calculations

[en] Objective: To explore the imaging and clinical features of chest wall lesions so as to improve diagnosis accuracies of the diseases. Method: Fifty children with chest wall lesions confirmed by surgery and pathology were enrolled from October 2009 to June 2018 into this study. The 50 cases included 4 infectious lesions and 46 non-infectious lesions which was composed of benign tumors and malignant tumors. All patients underwent US, chest CT and MRI. Clinical data and imaging findings were retrospectively analyzed, and relevant literatures were reviewed. Results: There were obvious difference in clinical and imaging findings among three groups (infection, benign tumor, and malignant tumor). 1. Clinical finding: all infectious cases presented fever, chest pain, and local redness, swelling, and heat. All the infectious lesions were soft, 37 of 41 (90.2%) benign tumors were soft, and all the malignant tumors were firm. The lesions presented a limited mobility in all the groups. Local tenderness was presented in all the infection and malignant tumor groups. However, in the benign tumor group, local tenderness was presented in 3 of 41 cases (7.3%), which was significantly lower than in the other groups. 2. Imaging finding: in the benign tumor group, lesions showed heterogeneous density in 31 cases and well-defined margin in 27 cases. The incidences were 75.6% (31/41) and 65.9% (27/41), respectively. However, in the infection and malignant tumor groups, all the lesions appeared heterogeneous density and indistinct margin. In the benign tumor group, there were 4 cases presented calcification (9.8%), 1 hemorrhage (2.4%) and 8 cystic spaces (19.5%). Rib destruction was found in 6 of 41 cases (14.6%) in the benign tumor group. All malignant tumors showed rid destruction, and the lesions even involved thoracic cavity. No rib damage was found in the infection group. Lesions showed obvious enhancement in all the infection and malignant tumor groups, but non-enhancement to mild enhancement was observed in 33 of 41 cases (80.5%) in the benign tumor group. Conclusion: Different chest wall lesions have different and specific clinical characteristics. We can make a better diagnosis by combining with the clinical and imaging features. (authors)

[en] Objective: To analyze the imaging features of solid pseudopapillary neoplasm of pancreas (SPN) in children, and to improve the awareness of the disease. Methods: From January 2007 to December 2016, 12 patients with SPN proven pathologically were enrolled in the study, of whom 12 cases underwent CT scanning and 3 cases underwent MRI scanning. The imaging data of SPN were analyzed retrospectively. The tumor parameters included the location, size, shape, margin, capsule, form, enhancement degree, and presence of calcification, biliary obstruction, surrounding, ascites, lymph node metastasis, as well as distant metastasis, which were comparative analyzed with that of pathology. Results: CT showed that 3 cases were located in the head of pancreas, 7 cases were located in the body/tail of pancreas, and 2 cases were ectopic. Twelve cases were circular tumors, the diameter of which ranged from 28-76 mm (median diameter 48 mm). Capsules were showed in 10 cases, calcification was seen in 4 cases and hemorrhage was seen in 1 case. Three cases were solid, 8 cases were solid and cystic mixed, and 1 case was cystic. The tumors were heterogeneous, and the solid portion of SPN was moderately to obviously enhanced gradually whereas the cystic part remained unenhanced. Nine cases showed that the tumors grew to the outside of pancreas, in which 4 cases covered by the normal pancreas tissue, 1 case located inside of the pancreas. One case caused biliary obstruction and the collateral circulation of splenic arteriovenous was established in 2 cases due to tumor compressed. Ascites was seen in 2 cases. MRI showed that the cystic components of tumor in 3 cases showed low signal in T₁WI and high signal in T₂WI, with no enhancement. The solid components of the tumor showed equal signal in T₁WI and slightly higher signal in T₂WI, with obvious enhancement. Capsules were showed in 3 cases with low signal in T₁WI and T₂WI, which were obviously enhanced in 2 cases and without enhancement in 1 case; hemorrhage was showed high signal in T₁WI in 1 case. No lymph node metastasis and distance metastasis were observed in 12 cases. Conclusions: The characteristic imaging findings of SPN in children are boundary clear, capsules, calcification, circular pancreas tumors, which grow to the outside of pancreas, with varied degrees of hemorrhage and necrosis. The solid portion of SPN is moderately or obviously enhanced gradually. (authors)

[en] Steel is the most widely used material in engineering for its cost/performance ratio and coatings are routinely applied on its surface to further improve its properties. Diamond coated steel parts are an option for many demanding industrial applications through prolonging the lifetime of steel parts, enhancement of tool performance as well as the reduction of wear rates. Direct deposition of diamond on steel using conventional chemical vapour deposition (CVD) processes is known to give poor results due to the preferential formation of amorphous carbon on iron, nickel and other elements as well as stresses induced from the significant difference in the thermal expansion coefficients of those materials. This article reports a novel approach of deposition of nanocrystalline diamond coatings on high-speed steel (M42) substrates using a multi-structured molybdenum (Mo) – tungsten (W) interlayer to form steel/Mo/Mo-W/W/diamond sandwich structures which overcome the adhesion problem related to direct magnetron sputtering deposition of pure tungsten. Surface, interface and tribology properties were evaluated to understand the role of such an interlayer structure. The multi-structured Mo-W interlayer has been proven to improve the adhesion between diamond films and steel substrates by acting as an effective diffusion barrier during the CVD diamond deposition

[en] The graphite-like carbon (GLC) coating with low friction and good wear resistance is appreciable to make further improvement. Ce, Y and Ta are doped into GLC by using mosaic in the target of magnetron sputtering process. The result shows that yttrium composed in chromium interlayer can increase the bonding strength and refine the microstructure of the GLC coating. For the surface layer of GLC, incorporation of Ta improves wear resistance and deposition rate, in the mean time the friction coefficient is decreased. As the modifications of interlayer and top layer are composed together to form complex GLC coating, the specific wear rate is reduced and the hardness, bonding strength and anti corrosion behavior are improved.

[en] Hard Cr-N and silicon doped Cr-Si-N nanocomposite coatings were deposited using closed unbalanced magnetron sputtering ion plating system. Coatings doped with various Si contents were synthesized by changing the power applied on Si targets. Composition of the films was analyzed using glow discharge optical emission spectrometry (GDOES). Microstructure and properties of the coatings were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and nano-indentation. The harnesses and the elastic modulus of Cr-Si-N coatings gradually increased with rising of silicon content and exhibited a maximum at silicon content of 4.1 at.% and 5.5 at.%. The maximum hardness and elastic modulus of the Cr-Si-N nanocomposite coatings were approximately 30 GPa and 352 GPa, respectively. Further increase in the silicon content resulted in a decrease in the hardness and the elastic modulus of the coatings. Results from XRD analyses of CrN coatings indicated that strongly preferred orientations of (111) were detected. The diffraction patterns of Cr-Si-N coatings showed a clear (220) with weak (200) and (311) preferred orientations, but the peak of CrN (111) was decreased with the increase of Si concentration. The XRD data of single-phase Si₃N₄ was free of peak. The peaks of CrN (111) and (220) were shifted slightly and broadened with the increase of silicon content. SEM observations of the sections of Cr-Si-N coatings with different silicon concentrations showed a typical columnar structure. It was evident from TEM observation that nanocomposite Cr-Si-N coatings exhibited nano-scale grain size. Friction coefficient and specific wear rate (SWR) of silicon doped Cr-N coatings from pin-on-disk test were significantly lower in comparison to that of CrN coatings.