[en] The single anode magnetron injection gun which will be employed to 8 mm gyrotron of the casing by the permanent magnet experiments is designed. Firstly, analytic equations based on adiabatic theory and angular momentum conservation are used to examine initial design parameters of the electrode shapes. Secondly, the method of the numerical calculation is discussed and selected. Thirdly, the Numerical calculation and optimization are carried out by use of an self-redact electron trajectory code, the space charge effects and the velocity spreads are discussed. Lastly, the optimal parameters with electrode shapes and electronic trajectory were obtained. The single anode magnetron injection gun was employed in the experiments of the gyrotron

[en] Designing highly efficient dialkylphosphinic acid extractant for zirconium/hafnium separation relies on systematic structure-property studies. In this paper, dialkylphosphinic acids with different substituents at β-C, γ-C and δ-C for zirconium and hafnium extraction and separation from H₂SO₄ media were investigated. The results show that substituents at β-C, γ-C and δ-C reduce the extraction ability of dialkylphosphinic acids for both zirconium and hafnium. The substituent effect at β-C is greater than that at γ-C and δ-C. The larger steric hindrance of the substituents (ethyl > methyl > H), the weaker extraction ability of the dialkylphosphinic acids. The zirconium and hafnium separation behavior is related to the extraction ability of dialkylphosphinic acids. Dialkylphosphinic acids with stronger extraction ability show better zirconium/hafnium separation performance at higher acidity of 2.0 mol L^-1 H₂SO₄, while those with weaker extraction ability show better zirconium and hafnium separation performance at lower acidity of 0.25 mol L-1 H₂SO₄. The highest hafnium/zirconium separation factor (β_Hf/Zr) in the current study occurs with (2-ethylhexyl) (2,4,4-trimethylpentyl)phosphinic acid (USTB-1), which reaches 19.2. (author)

[en] Critical free-area ratio (CFR) is an interesting phenomenon during the snow-melting process on pavement using low-temperature heating fluids such as geothermal tail water and industrial waste water. This paper is performed to further investigate the mechanism of CFR and its influencing factors. A simplified theoretical model is presented to describe the heat and mass transfer process on pavement. Especially the variation of thermal properties and the capillary effect of snow layer are considered. Numerical computation shows that the above theoretical model is effective for the prediction of CFR during the snow-melting process. Furthermore, the mechanism of CFR is clarified in detail. CFR is independent of the layout of hydronic pipes, the fluid temperature, the idling time, and weather conditions. It is both the non-uniform temperature distribution and complicated porous structure of snow layer that lead to the occurrence of CFR. Besides, the influences of operation parameters including the fluid temperature, the idling time, the pipe spacing and buried depths on snow melting are analyzed, which are helpful for the next optimal design of snow-melting system

[en] A single anode magnetron injection electron gun is designed and calculated according to the requirements of gyrotrons with a presented method, which combines synthesis with analysis. A set of computer program has been developed. The electrode shapes, electron trajectory and electron beam parameters are also given with the computer aided design. The electron gun has the characteristics such as small velocity spread, good laminar flow and small volume etc. This gun was applied in the experiment, which shows a gun designed with the method has obtained 127 kW peak power with over 10% efficiency

[en] Multilayer metal hot forging dies deposited by the plasma transferred arc welding presents high wear resistance, oxidation resistance and high temperature stability. In the process of hot forging, bending load made the cavity of multilayer metal hot forging die easily failure. We investigated the bending performance of multilayer metal hot forging die by three-point bending test. The model of bending specimen used H13 as the substrate, transition layer was W6Mo5Cr4V2 and outer layer was Ni60A. Mechanical properties of H13 homogeneous specimens and multilayer metal specimens were tested and compared. ABAQUS finite element method was used to simulate the process of three-point bending under temperature gradient. The results show that crack appears firstly in the H13 substrate and Ni60A layer, expands and meets in the transition layer gradually, results in specimen fractures. At service temperature, bending performance of the multilayer metal specimens is better than homogeneous specimens. (paper)

[en] Road ice and snow melting based on low temperature geothermal tail water is of significance to realize energy cascading utilization. A small scale ice and snow melting system is built in this work. Experiments of dynamic melting processes of crushed ice, solid ice, artificial snow and natural snow are conducted on concrete pavement. The results show that the melting process of ice and snow includes three phases: a starting period, a linear period and an accelerated period. The critical value of the snow free area ratio between the linear period and the accelerated period is about 0.6. The physical properties of ice and snow, linked with ambient conditions, have an obvious effect on the melting process. The difference of melting velocity and melting time between ice and snow is compared. To reduce energy consumption, the formation of ice on roads should be avoided if possible. The idling process is an effective pathway to improve the performance of melting systems. It is feasible to utilize geothermal tail water of about 40 deg. C for melting ice and snow on winter roads, and it is unnecessary to keep too high fluid temperatures during the practical design and applications. Besides, with the exception of solid ice, the density and porosity of snow and ice tend to be decreasing and increasing, respectively, as the ambient temperature decreases

[en] Based on the service environment and requirements of hot working die,we proposed a H13-Cr₂C₃-CaF₂ self-lubricating material formula system and powder metallurgy process parameters, and prepared the high temperature composite materials. The phase composition and distribution of H13-Cr₂C₃-CaF₂ samples were analyzed by energy dispersive spectrometer. The friction coefficient, wear rate, wear morphology and spectrum of samples with different contents of CaF₂ were tested and compared by ball-on-disc high temperature tribometer under the conditions of test temperature 600 °C, disk rotation speed 200 r/min and friction for 15 min,and the mechanism of high temperature friction and wear was described. It will support the green manufacturing and sustainable development of forging industry. (paper)

[en] High-temperature self-lubricating materials based on H13 steel are prepared by the powder metallurgy method. The sintering process, phase addition and high-temperature testing of the material are studied so that the mechanical and wear performance of the composites can be optimized. The results show that the optimum sintering process is 2 h at a temperature of 1250 °C. When the contents of Cr₂C₃ and CaF₂ are 10%, the mechanical and sintering properties of the composites are acceptable. The relative density reaches 80.2% and the bending strength reaches 720.2 MPa. Moreover, CaF₂ effectively reduces the friction coefficient and wear rate of the material. The friction coefficient decreases to a minimum of 0.24, but the wear rate increases to a maximum of 7.26 × 10⁻⁵ mm²/min at a load of 1065 g. Cr₂C₃ helps to alleviate the oxidation of the composites, and the precipitation of CaF₂ causes network cracks to reduce the thermal fatigue performance.

[en] Genome-wide changes in DNA methylation are an epigenetic phenomenon that can lead to the development of disease. The study of global DNA methylation utilizes technology that requires both expensive equipment and highly specialized skill sets. We have designed and developed an assay, CpGlobal, which is easy-to-use, does not utilize PCR, radioactivity and expensive equipment. CpGlobal utilizes methyl-sensitive restriction enzymes, HRP Neutravidin to detect the biotinylated nucleotides incorporated in an end-fill reaction and a luminometer to measure the chemiluminescence. The assay shows high accuracy and reproducibility in measuring global DNA methylation. Furthermore, CpGlobal correlates significantly with High Performance Capillary Electrophoresis (HPCE), a gold standard technology. We have applied the technology to understand the role of global DNA methylation in the natural history of lung cancer. World-wide, it is the leading cause of death attributed to any cancer. The survival rate is 15% over 5 years due to the lack of any clinical symptoms until the disease has progressed to a stage where cure is limited. Through the use of cell lines and paired normal/tumor samples from patients with non-small cell lung cancer (NSCLC) we show that global DNA hypomethylation is highly associated with the progression of the tumor. In addition, the results provide the first indication that the normal part of the lung from a cancer patient has already experienced a loss of methylation compared to a normal individual. By detecting these changes in global DNA methylation, CpGlobal may have a role as a barometer for the onset and development of lung cancer

[en] A new Zr/Hf separation system was developed with a novel unsymmetrical dialkylphosphinic acid extractant (n-octyl)(2,4,4'-trimethylpentyl)phosphinic acid (INET-1). It selectively extracts Hf over Zr, and shows much better Zr/Hf separation efficiency than organophosphorous acid Cyanex 272. The Zr and Hf extraction reactions at acidities of < 2 mol/L H₂SO₄ and > 5.5 mol/L H₂SO₄ are revealed, respectively. An organic phase with 10 mmol/L INET-1 can load > 290 mg/L of Hf at 1 mol/L H₂SO₄. Acidic H₂SO₄ solutions with concentration of 3.0 - 4.5 mol/L is a good Zr scrubbing agent. (author)