This paper introduces recent activities on Marx-based compact repetitive pulsed power generators at the Institute of Applied Electronics (IAE), China Academy of Engineering Physics (CAEP), over the period 2010–2018. A characteristic feature of the generators described is the use of a simplified bipolar charged Marx circuit, in which the normal isolation resistors or inductors to ground are removed to make the circuit simpler. Several pulse-forming modules developed to generate a 100 ns square wave output are introduced, including thin-film dielectric lines of different structures, a pulse-forming line based on a Printed Circuit Board, and non-uniform pulse-forming networks. A compact repetitive three-electrode spark gap switch with low-jitter, high-voltage, and high-current was developed and is used in the generators. A positive and negative series resonant constant current power supply with high precision and high power is introduced. As an important part of the repetitive pulse power generator, a lower jitter pulse trigger source is introduced. Several typical high-power repetitive pulsed power generators developed at IAE are introduced including a 30 GW low-impedance Marx generator, a compact square-wave pulse generator based on Kapton-film dielectric Blumlein line, a 20 GW high pulse-energy repetitive PFN-Marx generator, and a coaxial Marx generator based on ceramic capacitors. The research of key technologies and their development status are discussed, which can provide a reference for the future development and application of miniaturization of compact and repetitive Marx generators.

In situ U–Pb and Hf analyses were used for crustal zircon xenocrysts from Triassic kimberlites exposed in the Rangnim Massif of North Korea to identify components of the basement hidden in the deep crust of the Rangnim Massif and to clarify the crustal evolution of the massif. The U–Pb age spectrum of the zircons has a prominent population at 1.9–1.8 Ga and a lack of Archaean ages. The data indicate that the deep crust and basement beneath the Rangnim Massif are predominantly of Palaeoproterozoic age, consistent with the ages of widely exposed Palaeoproterozoic granitic rocks. In situ zircon Hf isotope data show that most of the Palaeoproterozoic zircon xenocrysts have negative ϵHf(t) values (−9.7 to +0.7) with an average Hf model age of 2.86 ± 0.02 Ga (2σ), which suggests that the Palaeoproterozoic basement was not juvenile but derived from the reworking of Archaean rocks. Considering the existence of Archaean remanent material in the Rangnim Massif and their juvenile features, a strong crustal reworking event is indicated at 1.9–1.8 Ga, during which time the pre-existing Archaean basement was exhausted and replaced by a newly formed Palaeoproterozoic basement. These features suggest that the Rangnim Massif constitutes the eastern extension of the Palaeoproterozoic Liao–Ji Belt of the North China Craton instead of the Archaean Liaonan Block as previously thought. A huge Palaeoproterozoic orogen may exist in the eastern margin of the Sino-Korean Craton.

Several epidemiological studies have investigated that Na or K intakes might be associated with the metabolic syndrome (MetS). However, little evidence has evaluated the association between Na:K ratio and the MetS. In this study, we assessed the association between the dietary Na:K ratio and the MetS. The cross-sectional study was conducted among adults aged 18 years and older in Nanjing, using a multi-stage random sampling method, which resulted in a sample size of 1993 participants. Dietary Na and K intakes were assessed by 3 consecutive days of dietary recollection combined with condiments weighing method. Health-related data were obtained by standardised questionnaires, as well as physical examinations and laboratory assessments. The prevalence rate of the MetS was 36·5 % (728/1993). After adjusting for various lifestyle and dietary factors of the MetS, participants in the highest quartile of dietary Na:K ratio were at a higher risk of developing MetS (OR=1·602; 95 % CI 1·090, 2·353) compared with those in the lowest quartile. Each 1-sd increase in dietary Na:K ratio was associated with a higher risk of prevalent MetS (OR=1·166; 95 % CI: 1·018, 1·336). Among the components of the MetS, dietary Na:K ratio was positively associated with high blood pressure (quartile 3 v. quartile 1: OR=1·656; 95 % CI 1·228, 2·256) and hypertriacylglycerolaemia (quartile 4 v. quartile1: OR=1·305; 95 % CI 1·029, 1·655) in multivariate analysis. These results revealed that higher dietary Na:K ratio significantly increased the risk of the MetS in Chinese adults. Further studies are needed to verify this association.

A series of Ba-modified MnCeOx/TiO2 catalysts were prepared by a wet impregnation method and tested for selective catalytic reduction (SCR) of NO with NH3 at low temperature. The results showed that Ba additives obviously improved the catalytic performance of the MnCeOx/TiO2 catalyst for NH3-SCR, and the BaMnCeOx/TiO2 catalyst with 3 wt% BaO exhibited the optimal catalytic performance. Moreover, the introduction of Ba also improved the resistances toward water vapor and SO2 of catalysts. The N2 adsorption, H2-TPR, and X-ray photoelectron spectroscopy results showed that the addition of Ba increased the specific surface area, redox properties, and concentrations of surface Mn4+ and chemisorbed oxygen of catalysts. Furthermore, NH3-TPD and NO-TPD were used to investigate the absorption of NH3 and NO on the catalyst. The results revealed that although the introduction of Ba significantly promoted the adsorption of NO, it also inhibited the adsorption of NH3. Consequently, the catalytic performance of MnCeOx/TiO2 was greatly improved with the Ba additives.

The aim of this study was to determine whether vitamin D supplementation and maintaining vitamin D sufficiency are associated with changes in inflammatory and metabolic biomarkers in patients with knee osteoarthritis (OA) and vitamin D deficiency. A total of 413 participants with symptomatic knee OA and vitamin D deficiency were enrolled in a randomised, placebo-controlled trial and received 1·25 mg vitamin D3 or placebo monthly for 24 months across two sites. In this post hoc analysis, 200 participants from one site (ninety-four from the placebo group and 106 from the vitamin D group; mean age 63·1 (sd 7·3) years, 53·3 % women) were randomly selected for measurement of serum levels of inflammatory and metabolic biomarkers at baseline and 24 months using immunoassays. In addition, participants were classified into two groups according to serum 25-hydroxyvitamin D (25(OH)D) levels at months 3 and 24: (1) not consistently sufficient (25(OH)D≤50 nmol/l at either month 3 or 24, n 61), and (2) consistently sufficient (25(OH)D>50 nmol/l at both months 3 and 24, n 139). Compared with placebo, vitamin D supplementation had no significant effect on change in serum high-sensitive C-reactive protein, IL-6, IL-8, IL-10, leptin, adiponectin, resistin, adipsin and apelin. Being consistently vitamin D sufficient over 2 years was also not associated with changes in these biomarkers compared with not being consistently sufficient. Vitamin D supplementation and maintaining vitamin D sufficiency did not alter serum levels of inflammatory and metabolic biomarkers over 2 years in knee OA patients who were vitamin D insufficient, suggesting that they may not affect systemic inflammation in knee OA patients.

Catalysts play essential roles in the chemical vapor deposition of single-wall carbon nanotubes (SWCNTs). In this article, we summarize studies on catalysts for the structure-controlled growth and mass production of SWCNTs, discussing the main progress and the remaining challenges.

Tomographic particle image velocimetry (TPIV) measurement with six high-resolution charge-coupled device (CCD) cameras is conducted to investigate flow structures over a finite circular cylinder with an aspect ratio of 2 ( $h/d=2$ ). This short wall-mounted cylinder is fully immersed in a thick turbulent boundary layer ( $\unicode[STIX]{x1D6FF}/h=1.025$ ). Focus is placed on the three-dimensional instantaneous vortex structures and their dynamic characteristics in the wake flow fields. Based on the present results, a refined topological model of the mean wake field behind the finite circular cylinder is proposed, where the spatial locations of the typical vortex structures and their interactions are described in more detail. Among the reported typical vortex structures (i.e. the horseshoe, tip, base, trailing and arch vortex), emphasis is laid on discussion of the tip and arch vortex. The instantaneous 3D M-shape arch vortex and an alternating large-scale streamwise vortex are first found in the present experiment, and their developments are also discussed. Therefore, it is suggested that the instantaneous finite-cylinder wake is dominated by the arch vortex system and the large-scale streamwise vortices. Moreover, in the instantaneous volumetric flow fields, both the antisymmetric and the symmetric wake behaviours are observed. With proper orthogonal decomposition (POD) analysis, the dynamic characteristics of the wake field are clarified. Different from the flow around an infinite cylinder without control, the third and fourth POD modes are characterized by low-frequency symmetric shedding. The low-frequency feature shown in the second mode pair is observed and associated with the occurrence of instantaneous symmetric 3D wake behaviour triggered by the low-aspect-ratio effect and the extension of the separated shear layer. The low frequency seems be attributed to the flapping phenomenon, i.e. oscillation of the recirculation in the backward-facing step flow. It is found that the flapping motion has a modulating effect on the occurrence of the antisymmetric shedding vortex and thus the large-scale streamwise vortex.

This telescope was designed for determining the trigonometric parallaxes of faint stars. The otpical configuration is a Ritchey-Chrétien system and has only a f/10 Cassegrain focus for photographic work.

The mounting is a combination of fork and yoke frame which can reduce the flexure due to gravity. A high speed digital servo-system was adopted for controlling and driving the telescope. At present some photographs of Comet Halley have been obtained.

The 1.56m astrometric telescope (Fig. 1) is designed mainly for determining trigonometric parallaxes of faint stars.

In order to keep the design as simple as possible, the telescope has only a Ritchey-Chretien focus and will accomodate plates 200 × 200 mm. We also plan to design several pieces of auxiliary equipment such as a medium dispersion grating spectrograph, a photometer, a reducing camera, and an electrographic camera, all of which are in the second stage of engineering. The whole project consists of four parts.

We examined the in vitro developmental competence of parthenogenetic activation (PA) oocytes activated by an electric pulse (EP) and treated with various concentrations of AZD5438 for 4 h. Treatment with 10 µM AZD5438 for 4 h significantly improved the blastocyst formation rate of PA oocytes in comparison with 0, 20, or 50 µM AZD5438 treatment (46.4% vs. 34.5%, 32.3%, and 24.0%, respectively; P < 0.05). The blastocyst formation rate was higher in the group treated with AZD5438 for 4 h than in the groups treated with AZD5438 for 2 or 6 h (42.8% vs. 38.6% and 37.2%, respectively; P > 0.05). Furthermore, 66.67% of blastocysts derived from these AZD5438-treated PA oocytes had a diploid karyotype. The blastocyst formation rate of PA and somatic cell nuclear transfer (SCNT) embryos was similar between oocytes activated by an EP and treated with 2 mM 6-dimethylaminopurine for 4 h and those activated by an EP and treated with 10 µM AZD5438 for 4 h (11.11% vs. 13.40%, P > 0.05). In addition, the level of maturation-promoting factor (MPF) was significantly decreased in oocytes activated by an EP and treated with 10 µM AZD5438 for 4 h. Finally, the mRNA expression levels of apoptosis-related genes (Bax and Bcl-2) and pluripotency-related genes (Oct4, Nanog, and Sox2) were checked by RT-PCR; however, there were no differences between the AZD5438-treated and non-treated control groups. Our results demonstrate that porcine oocyte activation via an EP in combination with AZD5438 treatment can lead to a high blastocyst formation rate in PA and SCNT experiments.

Change mode and effects analysis (CMEA) is a powerful technique for measuring product flexibility toward future changes and diminishing the cost of redesign as well as shortening time to market. As a systematic methodology, it provides an in-depth view for the investigation of potential changes, causes, and effects in designs, products, and processes. Traditional CMEA determines the risk priorities of change modes by using change potential number, which requires the risk factors of design flexibility, occurrence, and readiness to be precisely evaluated. However, this is not always possible in real applications due to the uncertainty and subjectivity involved in the early design stages. It has been criticized much for its deficiencies in criteria weighting of the risk factors, change potential number calculation, and risk priorities determination of the change modes. This paper presents a systematic evaluation approach for determining a more rational rank of change modes by combining with the entropy weight method, rough number, and grey relational analysis. In this study, the entropy weight method is adopted to calculate the relative importance of risk factors. Rough number is presented to aggregate individual weights and preferences, and to manipulate the vagueness in the evaluation process. Then a rough number enhanced grey relational analysis is proposed to evaluate the risk ranking of change modes. Finally, a practical example is put forward to validate the performance of the proposed method. The result shows that the proposed change mode evaluation method can effectively overcome the shortcomings of traditional CMEA and strengthen the objectivity of product flexibility measurement.

A series CeO2/Al2O3 catalysts was modified with rare earth element (La, Nd, Sm, Gd, and Tm) using extrusion method. The catalytic activities of the obtained catalysts were measured for the selective catalytic reduction (SCR) of NO with NH3 to screen suitable addition of rare earth element. These samples were characterized by X-ray diffraction (XRD), N2 adsorption (N2-BET), NH3 temperature-programmed desorption analyses (NH3-TPD), H2 temperature-programmed reduction (H2-TPR), Raman spectra, pyridine adsorption Fourier-transform infrared (Py-IR) and X-ray photoelectron spectroscopy (XPS), respectively. Results showed that the CeO2/Al2O3 exhibited excellent performance in resisting reactant poisoning caused by vapor and sulfur and the highest catalytic activity (98.35%) at 360 °C when the added Tm/Ce molar ratio is 0.10. The surface acidity of CeO2/Al2O3 catalyst would be enhanced with the addition of rare earth ions. Consequently, rare earth ion was beneficial to catalytic activity at low temperatures and corresponded to similar law. Analysis revealed that the higher number of acid sites and the more Ce3+ were conductive to obtain the excellent NH3-SCR activity.

A series of oxidation experiments were carried out on these novel γ/γ′-strengthened cobalt-based alloys of the systems Co–9Al–10W and Co–9Al–10W–0.02X (X = La, Ce, Dy, Y) at 900 °C. The appropriate amounts’ addition of rare earth elements leads to improved oxidation properties at 900 °C, especially La elements show the best oxidation resistance (129.008 mg/cm2). However, the base Co–9Al–10W alloy shows the worst oxidation performance (151.544 mg/cm2). Multilayer oxide layers formed during the oxidation process, the outer were mainly CoO and Co3O4 oxides, and the middle layer contained complex oxides (containing Co, Al, and W). The inner layer consists of little discontinuous oxides, included few Al2O3 oxides. There existed a different crack width and the base alloy had the widest crack. Moreover, there exists a phase transformation (γ/γ′ to γ/Co3W) at the interface between oxide film and substrate.

Dislocations are line defects in crystalline materials. The Peierls-Nabarro models are hybrid models that incorporate atomic structure of dislocation core into continuum framework. In this paper, we present a numerical method for a generalized Peierls-Nabarro model for curved dislocations, based on the fast multipole method and the iterative grid redistribution. The fast multipole method enables the calculation of the long-range elastic interaction within operations that scale linearly with the total number of grid points. The iterative grid redistribution places more mesh nodes in the regions around the dislocations than in the rest of the domain, thus increases the accuracy and efficiency. This numerical scheme improves the available numerical methods in the literature in which the long-range elastic interactions are calculated directly from summations in the physical domains; and is more flexible to handle problems with general boundary conditions compared with the previous FFT based method which applies only under periodic boundary conditions. Numerical examples using this method on the core structures of dislocations in Al and Cu and in epitaxial thin films are presented.

Commission 22 (Meteors, Meteorites and Interplanetary Dust) was established at the first IAU General Assembly held in Rome in 1922, with William Frederick Denning as its first President. Denning was an accountant by profession, but as an amateur astronomer he contributed extensively to meteor science. Commission 22 thus established a pattern that has continued to this day that non-professional astronomers were welcomed and valued and could play a significant role in its affairs. The field of meteors, meteorites and interplanetary dust has played a disproportional role in the astronomical perception of the general public through the majestic displays of our annual meteor showers. Those in the field deployed many techniques uncommon in other fields of astronomy, studying the “vermin of space”, the small solid bodies that pervade interplanetary space and impact Earth's atmosphere, the surface of the Moon, and that of our satellites in orbit. Over time, the field has tackled a wide array of problems, from predicting the encounter with meteoroid streams, to the origin of our meteorites and the nature of the zodiacal cloud. Commission 22 has played an important role in organizing the field through dedicated meetings, a data centre, and working groups that developed professional-amateur relationships and that organized the nomenclature of meteor showers. The contribution of Commission 22 to the field is perhaps most readily seen in the work of the presidents that followed in the footsteps of Denning.