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The fatigue strength of a component is known to highly depend on its surface quality, and it is thus necessary to develop a reliable and appropriate mathematical model for fatigue strength assessment that consider the effect of surface roughness. In this paper, different underlying physical mechanisms of the roughness effect at different regions of specimens were studied by fatigue testing of 7N01 aluminum alloy. For a quantitative analysis of the surface roughness effect, a revised stress field intensity approach for a fatigue strength assessment of microsized notches was proposed as a theoretical support. In the new model, a new form of weight function was built to adapt the characteristics of microsized notches. In addition, the effect of the field radius was fundamentally weakened on solution of the stress field intensity and the difficulty of fatigue failure region definition in the traditional method was overcome correspondingly in the proposed model, which made the calculated field strength accurate and objective. Finally, to demonstrate the validity of the revised approach quantitatively, specimens with conventionally sized notches were subjected to stress field intensity calculations. The results showed that the revised approach has satisfactory accuracy compared with the other two traditional approaches from the perspective of quantitative analysis.

Parameter estimation of the three-parameter Weibull distribution is an important problem in reliability analysis and statistical modeling. Random right-censored data are widely encountered in engineering practice. Conventional least squares (LS) methods usually construct the empirical cumulative distribution function (CDF) based on rank statistics. However, this empirical assumption cannot adequately capture the nonlinear variation in failure probability with time in the Weibull distribution. To address this limitation, an iterative conditional probability based on conditional failure probability (ICP-CDF) is proposed. The method uses the parameter estimates obtained from the conventional LS approach as initial values, adjusts the ranks of failure data according to conditional failure probabilities, and updates the empirical CDF accordingly. Within a unified least squares estimation framework, an ICP-CDF-LS parameter estimation method is developed, in which both the CDF and distribution parameters are updated iteratively. Simulation studies and case analyses demonstrate that, compared with the LS and MLE methods, the proposed approach achieves superior overall performance in terms of estimation accuracy and stability, making it more suitable for practical engineering applications.

The cubic stiffness force model (CSFM) and Bouc-Wen model (BWM) are introduced and compared innovatively. The unknown coefficients of the nonlinear models are identified by the genetic algorithm combined with experiments. By fitting the identified nonlinear coefficients under different excitation amplitudes, the nonlinear vibration responses of the system are predicted. The results show that the accuracy of the BWM is higher than that of the CSFM, especially in the non-resonant region. However, the optimization time of the BWM is longer than that of the CSFM.

[Purpose/significance] The internationalization of China's National Intelligence force is a very urgent and critical issue. At present, we have studied its policy, deployment, operation and infrastructure, but have not completed the research of the shape, structure and dynamic mechanism. [Method/process] This paper first puts forward the concept of the Development of National Intelligence Forces, and then makes a special study of the existing biological principles and the history of modern intelligence activities in China and the United States. [Result/Conclusion] The Development of the National Intelligence Force is a complex research topic, and the study of this concept has great reference significance for the internationalization of China's national intelligence. Therefore, we suggest that China should adopt a new model and gradually develop a modern national intelligence system and its capacity structure.

[目的/意义]中国国家情报力量的国际化问题,是个非常紧迫而关键的课题。目前,中国在对外政策、地缘部署、科学运筹、情报基础设施建设等方面的研究已经取得了初步成果,但对情报力量的规模形态、结构动力等方面的研究尚未展开。[方法/过程]首先提出国家情报力量的发育这一概念,并采用文献回顾、学科嫁接与历史研究3种方法,对现有的生物学发现和中美现代情报活动历史进行专题性研究。[结果/结论]国家情报力量的发育是个复杂而庞大的研究课题,它的研究对中国国家情报力量的国际化具有巨大的借鉴意义。因此,笔者建议中国采用战略牵引、政治主导、经贸主题、系统进化的发育模式,逐步培育起现代化的国家情报体系及其对应的能力结构。

Facing the growing high data rate and large communication capacity demands, optical communications are widely recognized to be used to implement satellite communications. For a space-based optical backbone network, an appropriately designed protocol stack is important. In this paper, we proposed a protocol stack that is suitable for a space-based optical backbone network. Following this, we then used software to simulate this stack, built a hardware platform to test it, and finally, analyzed the results. The results showed that the proposed protocol stack was well designed to provide efficient control and management of the space-based optical backbone network. It could improve management efficiency by collecting resources and automatically calculating and building route paths. It could also facilitate data forwarding in intermediate satellite nodes with limited source and power, by using an advanced orbiting systems (AOS) frame switching scheme to avoid unnecessary processes, such as unpacking, upper-layer processing and repacking for passing services. The protocol stack could also support the use of unidirectional links to improve the link resource utilization. Finally, it could also provide transparent transmission for different kinds of services.

This paper introduces a computationally efficient global sensitivity analysis method for quantifying the influence of uncertain clamp support conditions on the natural frequencies of aero-engine pipe systems. The dynamic model is based on a three-dimensional Timoshenko beam finite element formulation, with clamps represented as distributed spring elements possessing anisotropic stiffness. To overcome the prohibitive cost of traditional Monte Carlo simulation, the multiplicative dimensional reduction method (M-DRM) is integrated with variance decomposition theory. This approach approximates the high-dimensional frequency response function as a product of univariate components, enabling rapid computation of Sobol’ sensitivity indices with a computational cost reduced by three orders of magnitude. Numerical case studies on a planar Z-shaped pipe and a spatial series-parallel configuration reveal that clamp position parameters dominate the system’s natural frequency characteristics. For critical clamps, Sobol’ indices exceed0.8across multiple vibration modes, whereas stiffness parameters exhibit negligible influence. The proposed methodology provides a rigorous and efficient tool for identifying dominant uncertainty sources, guiding tolerance allocation in manufacturing, and informing robust support design for vibration-sensitive piping systems.

The reliability of aero engine has a direct impact on the flight safety of the whole plane. With the continuous improvement of performance requirements of aero engines, the related fatigue and reliability problems also appear. For the fatigue failure characteristics of the typical component (compressor disk) in an aero engine, the fatigue reliability of its multi-site damage structure in service is analyzed by using probability cumulative damage criterion in this paper. The probability distribution definitions of life, damage and damage threshold are discussed and the relationship among them is also introduced by the new proposed criterion. Meanwhile, a method to determine the probability distribution of cumulative damage threshold and probability life prediction is carried out, based on which a hierarchical index system of statistical analysis and reliability modeling principle on the system level is further constructed for compressor disk. At the end of the paper, a certain cruise of fighter plane is analyzed to verify the validity of the new model. Emphasizing the difference between the compressor disk and traditional component, the new reliability analysis model developed in this study is basically reasonable for most of the load histories for the compressor disk, other than the traditional one, especially for the changeable and complex cruise missions.

Presents the application of the system to a project in Dezhou. Tests the application effect and the COP of absorption heat pump units and the heat pump system. Analyses and evaluates the energy saving property of the system based on the test data, providing reference for other similar application.

Based on convenience and safety of historical data application, B/S mode is used instead of database management structure of C/S mode, and it can not only combine database and network, but also realize the safe use of historical data online. High-level programming language is used to develop a online management and application system of historical meteorological data based on B/S mode. System data import function can import ground report file sequence of Xuzhou （ including five county-level stations） into the database, construct Oracle database of Xuzhou and the five stations since 1953, and establish data tables of time, day, ten-day, monthly, quarterly and annual historical data, weather information and so forth. Management software of database server is established to realize instruction-level management and scheduling of database and a balanced distribution of resources among users. At the same time, a Web-based management application interface is set up to meet users＇ needs to retrieve a variety of repositories, and it provides statistical query of time, day, ten-day, monthly, quarterly and annual historical data and climate data for each meteorological element, thereby meeting the needs of meteorological research and all sectors of society for statistical query of meteorological data.