[en] Monitoring of grass α and grass β in drinking water in some regions and cities in Shanxi Province was conducted since 1988 by Shanxi Sanitation and Antiepidemic Station, with the distribution and characteristics of the grass (α and gross β ascertained prelimiarily in the province. This provides the baseline data for implementing drinking water radioactive sanitation standards in the province grass α and gross β and for developing reasonable monitoring program. (authors)

[en] We investigate the structures and magnetic properties of boron-doped manganese clusters using first-principle density functional theory. We arrive at the lowest energy structures for clusters by simultaneously optimizing the cluster geometries, total spins, and relative orientations of individual atomic moments. For Mn_nB (n=2–12) clusters, the theoretical results indicate that the B atom prefers the surface site for all the lowest-energy structures except Mn_1_0B cluster. The doped B atom enhances the stability of pure Mn_n cluster. We also have studied the magnetic behavior of Mn–B clusters in the size range. Based on the analysis of the different magnetic behavior of boron-doped manganese clusters, we have further studied Mn_9B_2 and Mn_8B_3 clusters and it indicates that the doping of non-magnetism B element can induce all the Mn atoms align ferromagnetic coupling. Furthermore, a stable pearl necklace nanowire ([Mn_8B_3]_n→_∞) which retains the ferromagnetic ordering of all the manganese atoms has been predicted. - Highlights: • The doped B atom enhances the stability of pure Mn_n (n=2–12) cluster. • The B can induce all the Mn atoms align ferromagnetic coupling in Mn_8B_3 clusters. • A stable ferromagnetic nanowire ([Mn_8B_3]_n→_∞) has been predicted.

[en] Objective: To understand the occupational hazard factors in the production process and preventive measures in a soda ash plant, provide the basis for prevention and treatment of occupational diseases. Methods: On-site occupational health investigation and detection of occupational hazards in the workplace were adopted to perform investigation and analysis on current status of occupational health. Results: The main occupational hazard factors in the factory included dust, ammonia, sodium carbonate, carbon monoxide, hydrogen chloride, hydrogen sulfide, noise, high temperature. The exceeded rates were 21.2% for dust, 14.9% for ammonia, 13.8% for sodium carbonate, and 11.8% for noise. Hydrogen chloride, hydrogen sulfide and high temperature were up to the national health standards. Conclusion: The protective measures and facilities of occupational hazards of this plant are feasible. The occupational health management system is relatively complete. But the indicators of some occupational hazard factors are high in this factory. It is necessary to improve the working environment, increase the protection degree and control the density and intensity of occupational hazard factors to prevent occupational disease. (authors)

[en] Background: In the design of AP1000, Reactor Coolant Pump (RCP) is welded directly to the Steam Generator (SG) channel head. But this design makes the flow field in the SG channel head and RCP inlet complex and there may be vortex in this flow field for which reason the SG outlet resistance will increase and affect the long-term steady operation. Purpose: For this issue, some companies made tests on it. But the cost of test is high and the applicability of the test result is limited. If the parameters or components size changed a little, the test result will be no longer applicable. This article aims to find a way to solve this problem. Methods: This article considers using PumpLinx, a 3-D CFD flow field analysis software to analyse the SG and RCP coupled flow field. First, Pro/ENGINEER is applied to establish the 3D model of SG channel head with two RCPs welded to it and then establish mesh in PumpLinx and then analyze the problem in PumpLinx with Dynamic Mesh method. Results: The flow filed varying condition of SG-RCP coupled part from RCP rotation beginning to steady operation and the vortex condition after steady operation are obtained so as to support plant design. Conclusions: PumpLinx is suitable for AP1000 reactor coolant pump flow field CFD analysis. (authors)

[en] A 2ω wedge design is proposed with KDP crystal to disperse the unconverted light away from the target in a high power laser facility for inertial confinement fusion. The ultraviolet B-integral problem is released, and about 1.2 times in color separation angle is achieved according to both theoretical and experimental investigations when compared with conventional 3ω wedge. The frequency conversion efficiency is unaffected when the wedge is along the non-sensitive axis of the tripler. (authors)

[en] By comparing and analyzing various frequency conversion schemes, a compatible harmonic generation system has been designed. With type-Ⅱ-type-Ⅱ crystal combination configuration, polarization mismatch third harmonic generation and type-Ⅱ orthogonal quadrate second harmonic generation can be quickly switched. The thicknesses were optimized to be 10 mm for both crystals by numerical simulation method, as a result, the requirements of high efficiency for long pulse with low intensity, as well as high stability for short pulse with high intensity, can be satisfied. (authors)

[en] The isolate of discharge chamber is a key issue of metal material shell PEPC. The authors have constructed the testing facilities for breakthrough and modulating discharge respectively. Testing samples of anodized film include three kinds of thickness which are 30μm, 60μm and 100μm respectively. Experiments and theoretical analysis display that the breakdown threshold of the film depends mainly on the thickness of non-hole layer, and the basic thickness for the isolating of PEPC's glow discharge chamber is 60 μm

[en] The electronic properties of hydrogen- and oxygen-terminated diamond surfaces exposed to the air are investigated by scanning probe microscopy (SPM). The results indicate that for the hydrogen-terminated diamond surface a shallow acceptor above the valence-band-maximum (VBM) appears in the band gap. However, the oxygen-terminated diamond film exhibits a high resistivity with a wide band gap. Based on the density-functional-theory, the densities of states, corresponding to molecular adsorbate in hydrogenated and oxygenated diamond (100) surfaces, are studied. The results show that the shallow acceptor in the band gap for the hydrogen-terminated diamond film can be attributed to the interaction between the surface C–H bonding orbitals and the adsorbate molecules, while for the oxygen-terminated diamond film, the interaction between the surface C–O bonding orbitals and the adsorbate molecules can induce occupied states in the valence-band

[en] It has the advantages of largely decrease the discharging parameters of PEPC through magnetron cathode. The results of experiments which in different size of cathode, different strength of magnetic and different gas pressure indicate that the uniform discharge can be got in a large range of magnetic strength. The small change of the sizes of cathode hardly effects the parameters and uniformity of discharge. The best parameters of glow discharge for 300 mm x 300 mm discharging chamber is given out

[en] A system for measuring optical performance of plasma electrode Pockels cell (PEPC) electron-optical switches is constructed, which provide with time and space resolution capabilities. The optical layout used to diagnose performance of the 240 mm x 240 mm PEPC are described. And the results of experiment are given