[en] As a method of seismic evaluation, seismic analysis is widely used in the safety evaluation of various equipment in nuclear power plant. At present, because of the different methods of bolt stress checking, the standard used is also different. In this paper, based on ASME and RCC-M standards, the stress evaluation method and evaluation basis are proposed for nuclear grade equipment designed according to different nuclear safety standards and bolts at different positions, which has reference significance for seismic analysis of nuclear grade equipment. (authors)

[en] Highlights: • TiO_2 blocking layer (BL) was synthesized using various methods. • Effect of BL characteristics on performance of perovskite solar cell was studied. • Charge transfer kinetics of perovskite solar cells with different BLs was explored. • We demonstrated efficient solar cells employing chemical bath deposition based BLs. - Abstract: Organolead trihalide perovskite materials have been successfully used as light absorbers in efficient photovoltaic (PV) cells. Cell structures based on mesoscopic metal oxides and planar heterojunctions have already demonstrated very impressive and brisk advances, holding great potential to grow into a mature PV technology. High power conversion efficiency (PCE) values have been obtained from the mesoscopic configuration in which a few hundred nano-meter thick mesoporous scaffold (e.g. TiO_2 or Al_2O_3) infiltrated by perovskite absorber was sandwiched between the electron and hole transport layers. A uniform and compact hole-blocking layer is necessary for high efficient perovskite-based thin film solar cells. In this study, we investigated the characteristics of TiO_2 compact layer using various methods and its effects on the PV performance of perovskite solar cells. TiO_2 compact layer was prepared by a sol-gel method based on titanium isopropoxide and HCl, spin-coating of titanium diisopropoxide bis (acetylacetonate), screen-printing of Dyesol’s bocking layer titania paste, and a chemical bath deposition (CBD) technique via hydrolysis of TiCl_4, respectively. The morphological and micro-structural properties of the formed compact TiO_2 layers were characterized by scanning electronic microscopy and X-ray diffraction. The analyses of devices performance characteristics showed that surface morphologies of TiO_2 compact films played a critical role in affecting the efficiencies. The nanocrystalline TiO_2 film deposited via the CBD route acts as the most efficient hole-blocking layer and achieves the best performance in perovskite solar cells. The CBD-based TiO_2 compact and dense layer offers a small series resistance and a large recombination resistance inside the device, and makes it possible to achieve a high power conversion efficiency of 12.80%.

[en] Under earthquake conditions, spring type safety valves of air conditioning water systems in nuclear power plants need to maintain their structural integrity and operability. In this paper, the design of the key parts of the safety valve, the calculation of the bolt pre-tightening force and the connection load were completed by the formula method. The finite element analysis method was used to complete the seismic analysis of the safety valve. Firstly, the finite element model of safety valve is established, and modal analysis is completed by means of finite element software. After determining that the first-order frequency is greater than the cutoff frequency of 33 Hz, the seismic analysis of the safety valve is completed by using the equivalent static method. Finally, the stress assessment and strength check were completed according to the ASME nuclear power code. The calculation results show that all parts of the safety valve meet the strength and deformation requirements under seismic conditions. The analysis method used in this paper has very good engineering value for the seismic design of safety valves in nuclear power plants. (authors)

[en] Based on the ANSYS Workbench 14.5 software, the seismic performance and natural frequency of a nuclear safety grade filter is analyzed, and the stress analysis under the SSE seismic load is carried out. Accord-ing to the ASME stress evaluation code, the stress and strain at the dangerous point of the filter are evaluated. The results show that the stress distribution does not exceed the limit value of the stress that the filter can bear, that is to say, the designed filter conforms to the design specifications and can meet the requirements of work-ing conditions. The results of this paper can provide a reference for the seismic analysis and further structural optimization design of this kind of nuclear safety filter. (authors)

[en] Investigates main critical process of the CAP1400 nuclear power reactor coolant system pipe bending, including setting of temporary pipe of medium-frequency bending, impelling speed, optimization of cooling way, solution treatment, also put forwards the inspecting and accepting of pipe bended and the quality control of bending process. (authors)

[en] In this paper, the numerical simulation method for the protection performance of liquid armor based on STF can be roughly summarized into two ways, containing the shell element simulation method based on the inter-yarns friction coefficient and the coupled Euler-Lagrangian simulation method. The shell element simulation method of inter-yarns friction coefficient has a single consideration for STF performance, but it has high calculation efficiency and low calculation cost. The coupled Euler-Lagrangian simulation method fully considers the shear thickening characteristics of STF, and comprehensively considers the characteristics of STF. The simulated performance gets closer to the actual situation, and it can also reveal the effect of STF in improving the protection performance. (paper)

[en] The electron field emission performance of screen-printed graphene cathode was studied. High-yield graphene was prepared by a modified Hummers method and hydrazine hydrate reduction process, and screen printing technology was used to prepare the graphene field emission cathode. This cathode structure satisfies the requirements of both good electrical conductivity and a high surface field enhancement factor, leading to excellent and stable field emission properties with a low threshold field (∼1.5 V μm^-1). Our work introduced a simple and convenient method suitable for large scale on different substrates, paving the way for more applications of graphene films.

[en] Seismic performance of nuclear power valve is one of the important indexes to measure its safety and reliability. In this paper, the seismic performance of a nuclear class I three-way valve is analyzed. Firstly, the influence of prestress on the natural frequency of valve is analyzed; Secondly, the method of applying boundary load of three-way valve is proposed and calculated based on workbench software; Finally, according to the RCC-M stress evaluation code, the dangerous points of valve components are determined and evaluated. The results show that the stress distribution of the four dangerous paths is within the limit value of the valve, that means, the designed Valve conforms to the design specification and can meet the working condition requirements. The results of this paper provide a reference for the seismic analysis and further structural optimization design of three-way valve. (authors)

[en] Connecting and unloading rod is one of the important processes in the drilling process of DTH drilling rig. The unloading device not only affects the operator’s labor intensity and safety, but also affects the efficiency of drilling rig and the service life of drilling rod. Therefore, the research and design of unloading rod structure is of great significance to improve the efficiency of DTH drilling rig. Firstly, the selection of unloading rod hydraulic cylinder is analyzed, including the calculation of main parameters, cylinder design, piston design and calculation, cushioning and exhaust device. Secondly, the clamp rod hydraulic cylinder is designed and calculated, including the structure of the clamp rod cylinder, the clamp force calculation of the clamp rod cylinder and the wall thickness calculation of the clamp rod cylinder. Finally, we set the structure and parameters correctly to increase the efficiency of the hydraulic cylinder of the down-the-hole drill in the field operation. (paper)

[en] Previous studies have demonstrated that angiogenesis inhibitors can enhance tumor inhibitory effects of chemo- and radiotherapy via their action on tumor vessels. Here, we studied the effect of the angiogenesis inhibitor, bevacizumab (Avastin), on boron distribution in a murine tumor model. The human head and neck squamous cell carcinoma cell line was used for inoculation into mice. Boron-10 concentrations in tissues were measured by prompt γ-ray spectrometry (PGA). Hoechst 33342 perfusion and p-boronophenylalanine (BPA) distribution were determined by immunofluorescence staining. Our results revealed enhanced tumor blood perfusion and BPA accumulation in tumors after Avastin treatment, suggesting that combination of angiogenesis inhibition with treatment with boron compound administration may improve the efficacy of boron neutron capture therapy (BNCT) by modifying tumor vessels. In addition, our results also demonstrated the usefulness of immunofluorescence staining for investigating boron compound distribution at the cellular level. (author)