Subjects: Nuclear Science and Technology >> Nuclear Science and Technology submitted time 2024-05-28
Abstract： The search and localization of unknown radioactive sources is an important research topic in the field of nuclear security inspection and nuclear emergency response. In order to improve the source finding efficiency and adapt to the multi-source environment detection, a particle filtering source finding method integrating the angle of arrival is proposed. Firstly, a hardware platform combining autonomous localization and angle-of-arrival sensing is constructed to introduce position and angle information to the detector; secondly, the angle-of-arrival information is taken into account on the basis of particle filtering, which can dynamically shrink the source searching area and improve the searching efficiency; lastly, the angle-of-arrival-guided robot attitude adjustment is adopted in the path planning of the autonomous source searching, which can enhance the flexibility of the robot in searching for the source. Simulation experiments prove that this method can work correctly and effectively, and tests using radioactive sources further verify the practicality of this method for multi-source search.
Subjects: Aviation & Aerospace >> Basic Disciplines of Aerospace and Technology submitted time 2024-02-07 Cooperative journals: 《应用力学学报》
Abstract：
The continuous gust aeroelastic response is generally analyzed and solved using random theory in engineering.By integrating the frequency response functions of the airplane with the power spectral density of excitation,the root mean square value of each degree of freedom can be obtained.The method is based on the linear solution in the frequency domain,and the nonlinear response analysis cannot be directly carried out.Therefore,based on the matched filter theory,a simplified calculation method for continuous gust response considering structure nonlinearity is described in this paper.By introducing a gust filter,which is connected in series to the aeroelastic dynamic system of the whole plane,a time-domain analysis model of continuous gust is obtained.Based on the root mean square value of the selected degrees of freedom,the matched filter theory is used to calculate a set of the “time correlated response for the other degree of freedom.On this basis,for the nonlinear structure model,by adjusting the impulse strength amplitude,the maximum response is found as the nonlinear result,and finally a nonlinear continuous gust response calculation method suitable for engineering and structural nonlinearity is established.The simulated results showed that the method established in this paper can be used to obtain the “time-correlated” response of each degree of freedom,and can also be used for structural nonlinear response calculation.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： This study first analyzes the driving factors of China’s realization of the “dual carbon” goals from the two aspects of necessity and urgency, and proposes that to achieve the “dual carbon” goals, China shall reshape the energy structure and related industrial systems in a scientific and orderly manner, in which technology innovation plays a crucial leading role. Then, based on the long-term research and deveopment in the energy field of the Chinese Academy of Sciences, the scientific and technological development path to lead the realization of the “dual carbon” goals with the concept of “multi-energy system integration” is proposed, and the connotation of the “multi-energy system integration” concept is elaborated into four technology development paths, including clean and efficient utilization and coupling substitution of fossil energy, multi-energy complementation and large-scale application of non-fossil energy, industrial low-carbon, and zero-carbon process reengineering,and digital, intelligent and multi-energy integration. Finally, suggestions are put forward to promote the implementation of the “multi-energy integration” technology development path.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： Scientific and technological innovation plays key supporting and leading roles to achieve “carbon peaking and carbon neutrality” goals (referred to as “dual carbon”). It is necessary to make sustained efforts in the three aspects, namely energy structure adjustment, energy consumption, and carbon sequestration, and build a novel multi-energy-integrated energy production and utilization system based on hydrogen energy, energy storage, and methanol, in which the main lines are clean and efficient utilization of fossil energy, large-scale utilization and complementation of clean energy, low-carbon reconstruction of industrial processes, and intelligent multi-energy integration of building and transportation. In 2022, the Chinese Academy of Sciences has launched the scientific and technological action plan to support dual carbon goals. By implementing eight major actions including strategic research, cross-innovation of basic frontiers, breakthroughs in key technologies, comprehensive demonstration of new technologies and other scientific and technological innovation, deploying talent team building, international cooperation, improvement of innovation system capabilities, and popular science and dissemination actions, the action plan is to provide vigorous scientific and technological support for China’s carbon peaking and carbon neutrality goals.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： Energy is the material basis for the survival and development of a country. Sustainable high-quality development of the economic society with the green transformation of energy resources is a long-term and tough task. The construction of clean, lowcarbon, safe and highly efficient energy system is an important strategic goal putting forward by the government for the future energy development of China, while technological innovation is the key to such goal. Based on the analysis of Chinese energy development status, major problems and great challenges, combining with global energy development trends, this study proposed a new idea on the development strategy of energy technology of China, the main line of which is the clean and efficient use of fossil resources and coupling substitution, multi-energy complementarity and scale application of clean energy, and the low-carbon multi-energy strategic integration.
Subjects: Astronomy >> Astrophysical processes submitted time 2022-11-17 Cooperative journals: 《天文研究与技术》
Abstract： We search for possible periodicity in the MOJAVE（Monitoring Of Jets in Active Galactic Nuclei with VLBA Experiments）observations at 15.3 GHz of eight Fermi blazars using the REDFIT method. Possible periodic components of about 1.77, 8.69, 2.04 and 7.65 years were found in the sources 0851+202, 1308+326, 1641+399 and 2251+158 at a 99% confidence level, respectively. The super-massive binary black hole model and the helical jet model have been used to explain these periodicities.And they are also used to caculate the central black hole masses of the four sources which is 109M⊙~1010M⊙.
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Basic Disciplines of Agriculture submitted time 2017-11-08 Cooperative journals: 《中国生态农业学报》
Abstract：覆膜种植是旱地春玉米种植的重要方式, 具有显著的增产作用。但前人对旱地春玉米在不同覆膜种植方式下的水分利用、根系发育及抗倒伏等增产机理方面研究较少。于2013—2015年在河北省沧州市农林科学院前营试验站开展田间试验, 连续3年研究露地平作(CK)、平作覆膜膜下播种(FC-SUF)、平作覆膜膜侧播种(FC-FSS)、起垄覆膜膜下播种(RC-SUF)、起垄覆膜膜侧播种(RC-FSS)等5种种植模式下春玉米产量及产量构成要素、土壤水分、作物根系和抗倒伏情况。结果表明: RC-FSS、RC-SUF、FC-FSS和FC-SUF比CK 3年分别平均增产24.97%、17.75%、11.69%和8.67%, 其中起垄覆膜侧播技术(RC-FSS)增产效果最优, 其水分利用效率比CK平均提高26.27%。RC-FSS处理垄沟处0~20 cm土壤含水量比CK增幅达30.44%~47.66%, 达极显著差异; RC-FSS处理的抗倒伏性最好, 其倒伏率仅为0.9%, 抗倒伏力最大为29.4 N, 与CK差异达显著水平。在玉米整个生育期内, 0~10 cm土壤温度各覆膜处理比CK平均增加0.3~2.3 ℃, 以RC-SUF种植模式下增温最显著。成熟期RC-FSS模式下根系分布直径、根系干重明显优于RC-SUF、FC-SUF和CK, 差异均达显著水平。研究表明, 春玉米起垄覆膜侧播技术具有集雨保墒、促根壮苗、高抗倒伏、增产稳产的作用, 在春季干旱少雨的滨海平原区有广阔的应用前景。
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