Influence of Indentation on the Fatigue Strength of Carbonitrided Plain Steel

To study the influence of indentation on the fatigue strength of untreated and carbonitrided specimens of S38C steel, the fatigue limit of specimens with and without indentations was tested. Fracture surfaces were observed using scanning electron microscopy (SEM). The results show that the fatigue strength of the untreated specimen decreases with increasing dimension of indentation, without significant difference compared to the predicted results. Compared to the fatigue limit of the untreated specimen, those of the carbonitrided specimen and the carbonitrided specimen whose compound layer was polished were improved by 12% and 40%, respectively. The fatigue strength of the carbonitrided specimen decreased sharply with increasing indentation size because of the presence of microcracks in the compound layer. When the compound layer was removed, the fatigue limit was observed to be less sensitive to indentation than that of the carbonitrided specimen

Seakeeping analysis of two ships advancing parallel for underway replenishment

Due to the wave and hydrodynamic interaction between two ships advancing parallel on the ocean, their six-degrees-of-freedom motions are much more complex during replenishment. The seakeeping performance of two vessels is analyzed with AQWA. On the basis of the RAO functions of the two parallel vessels, spectrum analysis and time-domain analysis were carried out, and the significant amplitudes were obtained using the computed time-history and correlation function method. The significant amplitudes are compared with the results of the spectrum analysis and good agreement is observed. It is found that hydrodynamic interaction between two ships has a great impact on the process of replenishment. Depending on the results of the analysis, dangerous conditions during the replenishment process could be avoided, thereby ensuring the safety of supply work

A phase Ⅱ, randomized, controlled trial to evaluate the safety and immunogenicity of a Sabin strain-based inactivated polio vaccine

This phase Ⅱ, randomized, controlled trial aimed to evaluate the safety and immunogenicity of a various Sabin IPV preparations. Six hundred infants aged 60 ~ 90 days received one of five different vaccines: low- (group A), medium- (group B) or high-D antigen content (group C) of an experimental Sabin IPV, control Sabin IPV (group D) or control Salk IPV (group E), on a 0-1-2 month schedule. Participants were observed and followed up within 30 days of each dose to assess safety. Serum samples were collected before the first dose and 30 days after the third dose to assess immunogenicity. After three doses, type-1 seroconversion rates of groups A–E were 99.1%, 100.0%, 99.1%, 99.0%, and 93.4%, respectively; type-2 seroconversion rates were 93.5%, 97.1%, 98.1%, 95.1%, and 91.5%, respectively; and type-3 seroconversion rates were 95.4%, 98.1%, 98.1%, 95.1%, and 100.0%, respectively. Only type-1 seroconversion rates differed significantly for group E. The incidences of injection-site redness (A: 21.9%, B: 23.7%, C: 29.4%, D: 16.2%, E: 12.7%), swelling (A: 6.7%, B: 6.8%, C: 5.0%, D: 0.0%, E: 1.7%) and pain (A: 5.0%, B: 6.8%, C: 7.6%, D: 0.0%, E: 0.9%) all were significantly higher for experimental vaccines relative to control groups. No SAEs were detected related to vaccination, and most adverse reactions were mild or moderate in severity. In conclusion, the experimental Sabin IPVs with low-, medium-, and high-D antigen content all revealed good safety and immunogenicity profiles although being more reactogenic than the control vaccines

Controlled Ambipolar Doping and Gate Voltage Dependent Carrier Diffusion Length in Lead Sulfide Nanowires

We report a simple, controlled doping method for achieving n-type, intrinsic, and p-type lead sulfide (PbS) nanowires (NWs) grown by chemical vapor deposition without introducing any impurities. A wide range of carrier concentrations is realized by adjusting the ratio between the Pb and S precursors. The field effect electron mobility of n-type PbS NWs is up to 660 cm²/(V s) at room temperature, in agreement with a long minority carrier diffusion length measured by scanning photocurrent microscopy (SPCM). Interestingly, we have observed a strong dependence of minority carrier diffusion length on gate voltage, which can be understood by considering a carrier concentration dependent recombination lifetime. The demonstrated ambipolar doping of high quality PbS NWs opens up exciting avenues for their applications in photodetectors and photovoltaics