[en] Graphical abstract: A novel N and F co-doped metal-free doped carbon catalyst with three dimensional vesicles structures and ultra thin walls are prepared by pyrolyzing the mixture of melamine and PTFE. The catalyst has high N and F contents (13 and 6 at.%), and exhibits high ORR activity, high stability, and high limitation current density in both alkaline and acid medium. - Highlights: • N and F co-doped carbon catalyst was derived from the mixture of PTFE and melamine. • The N and F contents of the catalyst are up to 13 and 6 at.%, respectively. • The catalyst has three dimensional vesicles structure with ultra thin walls. • ORR activity of the catalyst is superior to that of Pt/C catalyst in alkaline medium. - Abstract: A novel nitrogen and fluorine co-doped carbon catalyst (C-Mela-PTFE) is prepared by pyrolyzing a mixture of melamine and polytetrafluoroethylene (PTFE), the catalyst has a three-dimensional vesicular structure with ultrathin wall, and exhibits excellent ORR performance in both alkaline and acidic mediums. In an alkaline medium, the catalyst exhibits superior ORR activity to that of commercial Pt/C catalyst. Notably, the ORR activity of the catalyst is just slightly lower than that of Pt/C catalyst in acidic medium. It is interesting that the ORR limiting current density of our C-Mela-PTFE catalyst is much higher than that of Pt/C catalyst. The effects of the melamine/PTFE ratio and the pyrolysis temperature on the catalyst's ORR performance are investigated. The optimal melamine/PTFE ratio by weight is 1:1.5, and the optimal pyrolysis temperature is 950 °C. The catalyst samples are characterized by XRD, SEM/TEM, Raman analysis, and XPS, the results reveal the ultra-thin-walled vesicular structure, high surface area and porosity, and high doping amounts of N and F of the catalyst. For the optimal sample, the N and F contents are up to 13 and 6 at.%, respectively, the proportion of pyridinic N is up to 45 at.% according to the deconvolution results from its XPS spectrum. The ORR on our catalyst seems follow a four-electron transfer pathway, according to RDE-RRDE analysis results, the four-electron selectivity is up to 97%. We suggest that the high ORR performance of our catalyst is attributable to its high N content and high proportion of pyridinic N, co-doping of fluorine, as well as the high surface area and high porosity caused by its ultra-thin-walled vesicular structure.

[en] The reactor power control system is an important system for nuclear power plant power adjustment. Its performance directly affects the quality of power control of the entire plant. In the transformation of the 118 th overhaul of reactor power control system of Qinshan Phase I, on-site commissioning encountered many practical problems to be optimized. This paper fully expounds how to optimize the performance of the power regulation system during commissioning, mainly in terms of the axial power deviation ΔI over the target with the cumulative time long alarm function, the match of new transformation DCS control system and the old equipment interface range, counter accuracy compensation, human-machine interface process flow chart development, configuration function map optimization, etc. Departure, fully explain how to optimize the performance of the reactor power control system during the debugging process. through the research on these problem solutions, the performance of the reactor power control system would be improved, and the control quality should meet the design requirements of Qinshan First Plant. (authors)

[en] Highlights: • Graphene-like nori-derived carbon was prepared as a new cathode of Li-O_2 battery. • The battery showed superior round-trip efficiency and good cycling stability. • The NORI catalyst with LiI dramatically enhanced the performance of Li-O_2 battery. • The added LiI changed the morphology and chemical nature of the discharge products. - Abstract: To rapidly promote the development of electric vehicles, an efficient cathode catalyst for Li-O_2 batteries is urgently needed. In the present study, we prepared a new type of doped carbon catalyst derived from nori biomass for the cathode of Li-O_2 batteries, using a hydrothermal carbonization and pyrolysis method. The catalyst presented a graphene-like nanosheet structure, a high surface area, and excellent ORR/OER activity. Li-O_2 batteries with this catalyst exhibited superior round-trip efficiency (at current densities of 500 mA/g, the corresponding coulombic efficiency was 99.8%) and excellent cycling stability (100 stable cycles at 200 mA/g under capacity limitation). Furthermore, the charge–discharge overpotential could be reduced dramatically by adding LiI to the electrolyte, resulting in greatly enhanced battery performance. The battery’s energy efficiency was over 90%, even after 100 cycles at limited capacity. We concluded the following: (i) the high surface area and nanosheet structure of the nori catalyst provided sufficient space not only to accommodate the discharge products but also to guarantee that oxygen, soluble catalyst, and lithium ions could be freely transported; and (ii) these combined with the redox mediator LiI that was added to the electrolyte, which could freely access the interior of the air electrode, easily reacting with the solid discharge products and effectively changing the morphology and chemical nature of the discharge products. We believe these factors were responsible for the significantly enhanced performance of the resulting Li-O_2 batteries, suggesting this method may be a facile way to achieve a high-performance Li-O_2 battery.

[en] Thousands of kinds of proteins exist in a single cell. Proteomics research aims to characterize these proteins and simultaneously analyse modifications and interactions on a large scale. Here we present a label-free surface plasmon resonance (SPR) imaging interferometer based on spatial phase modulation, which can be useful in this field. It consists of a light source, a SPR sensing unit, a special phase modulator, a photoelectric conversion unit and a computer. Collimated light is projected into a prism and reflected at the gold–glass interface. The p- and s-polarized components of the reflected light pass through a one-dimensional beam expander and a Wollaston prism, and form an interference pattern on a CCD. Interference images are acquired and transferred to the computer for data processing. Protein interaction on the gold surface leads to a local refractive index change and results in interference fringe phase shift. By calculating the phase shift, interaction information can be obtained. It is demonstrated that this technique can detect different concentrations of NaCl solutions, and the phase change generated by a 0.9% NaCl solution is about 10°. In protein–protein interaction experiments, a model system of rabbit IgG and goat–anti-rabbit IgG is tested. The maximum phase change is up to 12°. The phase resolution of the system is 0.2°, equivalent to the refractive index resolution of 3 × 10⁻⁵ RIU, and this value can be improved to 2 × 10⁻⁶ RIU just by increasing the gold thickness of the sensing chip. It is concluded that the sensitivity of the interferometer is enough to achieve larger capacity than that detected by the present protein micro-array products. These results suggest that the SPR interferometer based on spatial phase modulation provides a potential facility to meet the requirements in proteomics research

[en] The trend toward miniaturization in manufacturing has led to a requirement for micro/nano measuring techniques capable of measuring tiny features on small components. In this paper we propose and demonstrate a novel scheme for micro/nano displacement measurement based on a double-FBG (fiber Bragg grating) sensing structure, a suspended FBG probe stem and a fiber fused micro-ball tip. Such a scheme has some advantages including robustness, sensitivity, small size with large aspect ratio attainable, simplicity and economy. The preliminary experiments showed that the prototype yielded a measurement resolution of 10 nm and a nonlinear error of 150 nm

[en] In this study, surface-enhanced Raman scattering(SERS)spectra of vitamin E were obtained on colloidal silver(Ag). Alpha-(-) tocopherol which is the only form that is recognized to meet human requirements was selected to study. The analytes (±)- -tocopherol were dissolved in chloroform (CHCl₃) and the silver colloid was poured into the compound. Silver colloid was reduced by hydroxylamine hydrochloride. The analytes were the supernatant after standing the mixture for the reason that chloroform have no signals in surface-enhanced Raman scattering in the Ag colloid, and it would not affect the determination of the (±)- -tocopherol. The Normal Raman and SERS spectrum of Vitamin E were contrastively studied to realize how the vitamin E stuck to the silver nanoparticles. The results show the fat-soluble substances can be analysed by SERS. The spectra indicate that the molecules are adsorbed on the surface through the COO- groups by the simultaneous involvement of a and -type coordination. These results suggest some important criteria for consideration in SERS measurements and also provide important insights into the problem of predicting SERS activities for different fat-soluble substances.

[en] Captopril, 1-[(2S)-3-mercapto-2-methyl propionyl]-Lproline, is an angiotensin converting enzyme (ACE) inhibitor, which reduces peripheral resistance and lowers blood pressure. It is widely used in the hypertensive ailments and incongestive heart failure treatment. Due to such crucial pharmacological importance, development of simple and accurate methods for the determination of captopril is desired. In this work, the normal Raman spectra of the captopril in different concentrations were studied, and the relationship between the Raman intensity and the concentrations of the captopril was quantificationally analysed. By selecting appropriate characteristic Raman bands of the cptopril, the solution of some captopril purchased in a local pharmacy was quantificationally determined. A quantificational linear relationship between the Raman intensity and the concentrations of captopril was obtained, and it is little affected by other compounds in the solution of captopril. This study provides an effective technique for the quantificational determination of captopril in solutions, and it has a potential application in the analysis of medicament.

[en] Higher-accuracy measurements of the 3D metrology of nano- and micro-structures are increasingly demanded. This paper details the prototyping of a novel 3D micro-scale coordinate measuring machine probe based on fiber Bragg grating sensors for true 3D measurements at micro- and nanometer scales. A new manufacturing technique for the high-precision cantilever used in the probe is also reported. Simulations are performed during the design and testing to help to test important aspects of the probe and to gain understanding about the influence of the probe geometrical parameters on the sensor sensitivity. The initial performance of the probe has been tested in both the vertical and horizontal directions, and the characterization results are promising. Further experimental results demonstrate that the probe is not affected by surface interaction forces. (paper)

[en] In this paper, two types of polyimide (PI) fibers, namely, PI-1 and PI-2, were modified using various treatments, including silane coupling agent KH-550, SiO₂ sol–gel, and ozone treatments. The surface properties of the PI fibers and the adhesion behavior of PI fiber/epoxy composites were evaluated. The chemical compositions and surface morphologies of the PI fibers were characterized by x-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. The results indicated that the interfacial properties of the PI fibers were enhanced after treatment with these three methods. In particular, the silane coupling agent exhibited the highest efficiency for surface modification. (paper)

[en] The activated carbon (AC) particles with different microstructures were used to support platinum active component by in-situ growing method, so as to prepare a series of Pt/AC structured catalysts. Compared to pure AC samples, the as-prepared Pt/AC catalysts do not have the limit of saturated adsorption capacity in the field of formaldehyde (HCHO) purification, and can be used for many times to eliminate HCHO pollutants at room temperature. Moreover, all the Pt/AC catalysts can maintain a high HCHO conversion of 75-85% in the multi-use test, indicating that the HCHO purification mechanism on the catalysts is a synergistic function of physical adsorption and catalytic oxidation. Furthermore, the HCHO oxidation activities of Pt/AC catalysts are also influenced by the microstructures of AC substrates, such as BET surface area, mesopore content and BJH pore volume. (paper)