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[en] A golden yellow-colored cerium conversion coating was obtained on 304 stainless steel surface by immersing the steel into a solution containing cerium (III), KMnO4 and sulfuric acid. The corrosion resistance of the coatings was evaluated by electrochemical methods, potentiodynamic polarization experiments and electrochemical impedance spectrum. The experimental results indicated that the corrosion resistance for the conversion coated 304SS in 3.5% NaCl solution increased markedly. The corrosion potential of the treated steel increased to a more noble level, the pitting corrosion potential increased also, the passive potential range was enlarged markedly and the passive current density decreased about one order compared to that of the untreated steel. The cathodic and anodic reaction were both inhibited to some extent. The chemical state of the elements in the coatings was investigated by XPS. The cerium element was in the form of tetravalent state. And AES depth profile analysis suggested that the thickness of the conversion coatings was less than 66 nm. The mechanisms of coatings formation and corrosion resistance are discussed
[en] With the consideration of coronal conditions, a simplified model and the steady-state rate-equation are used to calculate the isoelectronic line ratio for 1s22p(2P3/2)→1s22s(2S1/2) transition in Li-like Ti and Cr from the electron temperature 400 to 1100 eV. The relation between the isoelectronic line ratio and the electron temperature are provided under different mixture ratios of Ti and Cr. Then, the mixture ratio from 2:1 to 3:1 between Ti and Cr are obtained that are suitable for the electron temperature diagnostic by using isoelectronic line ratio of Li-like Ti and Cr. The relative abundance of two close ionization stages, which is from bare nucleus to Be-like ionization stage, are given and show that the He-, Li- and Be-like are the principal ionization stages from 400 to 1300 eV for Ti and from 500 to 1300 eV for Cr. The Li-like charge state will reach the maximum distribution approximately from 400 to 649 eV for Ti and from 547 to 900 eV for Cr. The paper also shows that the dielectronic recombination and spontaneous radiative recombination rates only have small effects on the isoelectronic line ratio in the electron temperature 400-1100 eV
[en] Although the interactions of soft x-rays and hard x-rays with polymers are fundamentally the same and are characterized by absorption and phase shifts, the relative and absolute strength of these interactions as a function of photon energy has profound practical implications. We delineate the basic physics of x-ray interactions with polymers as expressed in the optical constants of polymeric materials and exemplify the resulting advantages of soft x-rays over hard x-rays for real space and reciprocal space characterization methods in the context of a number of recent and ongoing applications. A perspective on future capabilities and applications will be provided.
[en] In order to develop a nontoxic radioprotector, 60 kinds of Chinese traditional medicines were chosen, and their aqueous extracts tested for their survival effects against the lethal effect of X-irradiation in mice. Radiation factors used were as follows: soft X-rays, 2100 R (5.418x10-1Ckg-1), 70 kVp, 10 mA, 10 mm acrylic filter, 70 R (1.806x10-2 Ckg-1)/min. Among 60 medicines tested by intraperitoneal injection immediately before the irradiation, 15 are shown to have the significant survival effect. These 15 effective medicines were also tested by intraperitoneal injection after the irradiation, and the survival effect was recognized in Keisi-syakuyaku-chimo-to, Keigai-rengyo-to, Shimotu-to, Syakuyaku-kanzo-to and Hange-syasin-to. On the other hand, the survival effects of 25 medicines including the above-mentioned 15 medicines were investigated by the oral administration at various times before or after the irradiation. As the results of these studies, only Keigai-rengyo-to and Bukuryo-in are shown to have the significant survival effect when administered 2 h before the irradiation. (author)
[en] This study is to investigate radioprotective effects of 23 Taiwan crude drugs on X-ray induced bone marrow death and skin injury in mice. Each methanol extract of these Taiwan crude drugs was injected intraperitoneally into ICR male mice at 6 weeks of age before irradiation. Mice were whole-body irradiated with a soft X-ray generator. Radiation factors of the two screening tests used were as follows: 70 kVp, 10 mA, 10 mm acrylate filter, 70 R/min, 2100 R for survival test, and 30 kVp, 10 mA, 190 R/min, 1100 R for protective test on skin injury. As a result of these studies, the survival effect was recognized in Solani Incani Herba and Orthosiphi Aristati Herba. On the other hand, Mimosae Herba, Canarii Radix, Bombacis Radix, Arecae Fructus, Hedyotidis Diffusae Herba and Cynomorii Caulis were shown to have significant protective potency on skin injury. (author)
[en] Through the study on the cost constituents of sandstone-hosted uranium deposit during the mining stage, and various parameters effecting the in-situ leach mining, the author tries to find out the mutual relationship among key parameters and determine the research method to set up a mathematical model. Then, the model is applied to make the technologic-economic evaluation
[en] Bashibulake uranium deposit is a deposit closely associated with oil-gas secondary reduction, which is located in Kashgar Sag in the west of China. Through analyzing the uranium mineralizing characteristics, ore formation and metallogenic mechanism from the point of geochemistry, it is considered that the formation of the deposit and the geochemical zonation in Lower Cretaceous are mainly caused by the reducing media such as CH4 in the oil and gas. At the same time, the reduction of liquid petroleum and land pitch, absorption of clay minerals also play some positive role in the ore formation. It tries to explain the ore-forming stages of uranium deposits and summarize its prospecting guides. (authors)
[en] A porous olefin-functionalized Zr(IV)-based metal–organic framework, denoted as UiO-68-allyl, has been constructed. Our results clearly demonstrated that the surface of UiO-68-allyl could be decorated with organic molecule (ethanethiol) via thiol-ene reaction. More importantly, the crystallinity of the framework were maintained during the post-synthetic modification process. However, the microporosity of the framework is retained but the surface area decreased, due to the grafting of ethylthio groups into the pores. From our studies, we can conclude that the strategy of post-synthetic modification of UiO-68-allyl via thiol-ene reaction may be general. Furthermore, we may anchor other desired functional group onto the pore walls in Zr-MOFs via thiol-ene reaction, enabling more potential applications. - graphical abstract: In this manuscript, we reported the post-synthetic modification of an olefin-functionalized Zr(IV)-based metal–organic framework via thiol-ene reaction. - Highlights: • A porous olefin-functionalized Zr(IV)-based metal–organic framework has been constructed. • The surface of olefin-functionalized Zr-MOF could be decorated with organic molecules via thiol-ene reaction. • The crystallinity and permanent porosity of the framework were maintained during the post-synthetic modification process
[en] The nonlocal beam theories are widely used to study the mechanics of cylindrical nanotubes (NTs). The one-dimensional models however are unable to account for the nonlocal effect in the circumferential direction, which may substantially affect the applicability of the nonlocal beam models. To address the issue this letter examines the circumferential nonlocal effect (CNE) on the buckling and vibration of the NTs. Here the CNE is characterized by the difference between the nonlocal beam model considering the axial nonlocal effect only and the nonlocal shell model with both axial and circumferential nonlocal effects. The aspect ratio and radius-dependence of the CNE are calculated for the singlewall carbon NTs selected as a typical example. The results show that the CNE is substantial for the buckling and vibration of the NTs with small radius (e.g., <1 nm) and aspect ratio (e.g., <15). It however decreases with the rising radius and the aspect ratio, and turns out to be small for relatively wide and long NTs. The nonlocal beam theories thus may overestimate the buckling load and vibration frequency for the thin and short NTs. - Highlights: • First revealed the substantial circumferential nonlocal effect (CNE) on nanotube buckling. • Achieved radius/aspect ratio-dependence of CNE on nanotube buckling and vibration. • Located the range of applicability of the nonlocal beam theory without CNE.
[en] Pressurizer is one of key components in nuclear power system. It's important to control the dimension in the design of pressurizer through optimization techniques. In this work, a mathematic model of a vertical electric heating pressurizer was established. A new Genetic-Simplex Algorithm (GSA) that combines genetic algorithm and simplex algorithm was developed to enhance the searching ability, and the comparison among modified and original algorithms is conducted by calculating the benchmark function. Furthermore, the optimization design of pressurizer, taking minimization of volume and net weight as objectives, was carried out considering thermal-hydraulic and geometric constraints through GSA. The results indicate that the mathematical model is agreeable for the pressurizer and the new algorithm is more effective than the traditional genetic algorithm. The optimization design shows obvious validity and can provide guidance for real engineering design