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The nanocrystalline-forming element Cu and magnetic element Co are commonly used as additive elements to tune the structure and improve properties of alloys. In this study, four kinds of amorphous alloys, Fe72Nb12B16, Fe72Nb12B15Cu1, Fe36Co36Nb12B16, and Fe36Co36Nb12B15Cu1, were prepared by melt-spinning and annealed at various temperatures to investigate the effects of Cu and Co additions, individually and in combination, on the crystallization and magnetic properties of Fe72Nb12B16 alloy. The four kinds of alloys exhibited different crystallization behaviors with different primary crystallization phases observed. For the Fe72Nb12B16alloy, only the α-Mn-type metastable phase formed after annealing. The addition of 1 at.% Cu and 36 at.% Co led to the observation of the α-Mn-type and β-Mn-type metastable phases, respectively, and a reduction in the crystallization volume fraction in the metastable phase. The Fe36Co36Nb12B15Cu1alloy only exhibited α-Fe(Co) phase as a primary phase, and the addition of both Cu and Co completely inhibited the precipitation of the metastable phase. Cu clusters were found in energy dispersive spectroscopy elemental maps. Compared with other alloys, Fe36Co36Nb12B15Cu1 alloy with both Cu and Co exhibited a lower coercivity (Hc) below 973 K.

Algorithms for wavefront sensing and error correction from intensity attract great concern in many fields. Here we propose Bayesian optimization to retrieve phase and demonstrate its performance in simulation and experiment. For small aberration, this method demonstrates a convergence process with high accuracy of phase sensing, which is also verified experimentally. For large aberration, Bayesian optimization is shown to be insensitive to the initial phase while maintaining high accuracy. The approach’s merits of high accuracy and robustness make it promising in being applied in optical systems with static aberration such as AMO experiments, optical testing shops, and electron or optical microscopes.

In order to analyze the influence of the material and shape of the hood of the medium-caliber PELE warhead on the damage effect of the reinforced concrete wall with PELE projectile, the three-dimensional nonlinear dynamic finite element program LS-DYNA was used to numerically simulate the penetration of the PELE projectile with the hood of different shapes and materials into the 0.25 thick thin reinforced concrete wall target at various velocities. The results show that under the same conditions, the hollow cone shaped phenolic resin hood can achieve better damage effect of reinforced concrete wall. Chinese map classification number: TP391.9 Document identification code: A

Both Nb and Mo additions play a vital role in FeCo-based alloys and it is crucial to understand their roles and contents on thermal behavior, microstructural feature and magnetic property of alloys. Nanocrystalline alloy ribbons Fe40Co40Zr9 – y M y B10Ge1 (y = 0–4; M = Nb, Mo) were prepared by crystallizing the as-quenched amorphous alloys. The effects of Nb and Mo additions on structures and properties of the Fe40Co40Zr9B10Ge1 alloy are investigated systemically and compared. With increasing Nb or Mo content, the primary crystallization temperature, grain size of α-Fe(Co) phase and coercivity H c all decrease. Moreover, the effect of Mo addition on thermal behavior, microstructure and magnetic properties of the FeCoZrBGe alloy is greater compared to Nb addition. The gap between primary and secondary crystallization peaks of Mo-containing alloys is wider than that of Nb-containing alloys. Both grain size and H c of Mo-containing alloys are smaller than those of Nb-containing alloys. For Fe40Co40Zr9B10Ge1 alloy, high Mo addition proportion is better compared to high Nb addition proportion.

In the iterative process of the update of the information service system, the continuous improvement of the system is restricted due to problems such as non-standard, incomplete, and strong ambiguity in the description of requirements. It makes it difficult to verify the consistency and integrity of requirements. In this paper, we focus on the huge requirements of complex information service system, and propose research on requirement itemized extraction and structured description technology based on natural language processing and requirement item keyword extraction and standardized expression technology. The library management system is used as the verification object to verify the effectiveness of the method proposed in this paper.

Many complex networks in real life are embedded in space and most infrastructure networks are interdependent, such as the power system and the transport network. In this paper, we construct two cascading failure models on the multilayer spatial network. In our research, the distancelbetween nodes within the layer obeys the exponential distributionP(l) ∼ exp(–l/ζ), and the lengthrof dependency link between layers is defined according to node position. An entropy approach is applied to analyze the spatial network structure and reflect the difference degree between nodes. Two metrics, namely dynamic network size and dynamic network entropy, are proposed to evaluate the spatial network robustness and stability. During the cascading failure process, the spatial network evolution is analyzed, and the numbers of failure nodes caused by different reasons are also counted, respectively. Besides, we discuss the factors affecting network robustness. Simulations demonstrate that the larger the values of average degree 〈k〉, the stronger the network robustness. As the lengthrdecreases, the network performs better. When the probabilitypis small, asζdecreases, the network robustness becomes more reliable. Whenpis large, the network robustness manifests better performance asζincreases. These results provide insight into enhancing the robustness, maintaining the stability, and adjusting the difference degree between nodes of the embedded spatiality systems.

Due to the long service life and corrosion problems of the pipeline in the fourth oil production plant of Huabei Oilfield, the increase of back pressure will increase the probability of pipeline perforation and lead to potential safety accidents. In view of this problem, based on the analysis of the composition and rheological law of crude oil, according to the scientific and reasonable experimental evaluation method, a new type of viscosity reducer system was developed by using the unique performance of surfactant. The viscosity reducer concentration of this system was 2%, compared with the blank crude oil, the average decrease of the freezing point of the crude oil was 5°C, The viscosity reduction rate is more than 60%, yield value reduction rate is more than 75%, and the low temperature fluidity of crude oil is improved. The expected target has been achieved through the dosing operation of two oil wells on site.

The operation with pressure is to carry out the lifting and lowering of the tubing or oil rod without releasing the pressure. Compared with traditional downhole operation, the operation with pressure can ensure the upward and downward of the string without pressure relief. The effective plugging of the inside of the oil pipe and the annulus of the oil jacket is the main characteristic of the operation under pressure. When the tubing is lifted, the interior of the tubing is sealed and blocked due to the downhole pressure, it will generate upward force on the tubing, which will make it difficult to run the tubing. The project uses a down-pressure device to assist the down-flow of the tubing. If the down-pressure is too large, buckling instability occurs, which increases the construction difficulty for the down-run operation. Combining elasto-plastic mechanics buckling instability theory and finite element simulation method to study the compression stability of tubing under pressure. The variation law of critical buckling force of tubing diameter, length and wall thickness under pressure is analyzed by numerical model, which provides the basis for equipment design and process plan formulation.

With the development of smart city, the concept of smart development is integrated into the construction management, so as to promote the smart development of construction and improve the efficiency of construction management. This paper discusses the application prospect of GIS-BIM integration technology in construction schedule management, site material management and safety management of construction personnel. At the same time, it looks into the application trend of gis-bim integration technology and global wide area network, Internet of things, virtual reality and other emerging technologies in the integration of building construction management, so as to promote the intelligent and visual management development of gis-bim integration technology in building construction management.

The NPU-WA airfoils were designed at high design lift coefficient and high Reynolds number, with small sensitivity of the maximum lift coefficient to leading edge roughness and excellent geometric compatibility. Compared to the widely used airfoils, the NPU-WA airfoils have higher lift-to-drag ratio and higher maximum lift coefficient. This paper aims to design a megawatt wind turbine blade in order to demonstrate the advantage of the NPU-WA airfoils. The distributions of chord length and twist angle for a 2 MW wind turbine blade are optimized by a kriging surrogate model-based optimizer, with aerodynamic performance being evaluated by blade element-momentum theory. Results show that compared with the baseline blade, the maximum power coefficient of the optimized NPU blade is larger, and the chord lengths at all span-wise sections are smaller, which is benefit to structural weight reduction. It is shown that the NPU-WA airfoils feature excellent aerodynamic for the design of megawatt wind turbine blades.

The number of aerodynamic analysis in the design optimization of propeller has been reduced significantly by using the surrogate model, such as kriging. In this paper, a more efficient aerodynamic design optimization method of propeller is proposed by using the HK (hierarchical kriging) model. The high-fidelity model is defined as a RANS (Reynolds- Averaged Navier-Stokes) simulation for propeller and the low-fidelity model is defined as the results by blade-element/vortex theory. Initial samples are selected for two levels of fidelity via LHS (Latin Hypercube Sampling). The aerodynamic performance of varying fidelity is used to build variable-fidelity surrogate models for functions of objective (e.g. thrust) and constraint (e.g. shaft power). Infill sampling criteria, including MSP (minimizing of surrogate prediction), EI (expected improvement), PI (probability of improvement), LCB (lower-confidence bounding) and MSE (mean-squared error) are used to obtain new samples, and the surrogate models are repetitively updated until a global optimum is found. High-altitude propellers are optimized by the kriging model and hierarchical kriging model, respectively. Compared to kriging model, the number of RANS solving by the hierarchical kriging model is reduced 37.5%, and the optimization time is reduced 24.3%. The results have shown that the proposed design method for propeller can significantly improve the optimization efficiency.

It is of practical significance to analyze the support requirements of each rescue team for the rationality of warehouse location. In order to solve the problem that the traditional emergency material storage warehouse does not consider the difference of material guarantee timeliness of rescue team, a generalized covering location model is proposed. In this paper, the coverage is introduced to measure the quality of security services in each disaster area, and the maximum generalized coverage model is established to find the best location scheme of emergency material storage warehouse. Finally, the feasibility of the method is verified by an example, and the proposed method can better solve the location problem of emergency materials storage warehouse.

Based on Compressive Sampling, the Modulated Wideband Converter (MWC) sampling method can implement sampling at a rate lower than the required by Nyquist theory. This paper designs a spectrum reconstruction system, based on MWC, which can reconstruct the spectrum of Sparse-Frequency signal at the rate lower than Nyquist-Frequency, and verify through the simulation signals and the measured fault bearing vibration signals.