Subjects: Physics >> Nuclear Physics submitted time 2023-09-04 Cooperative journals: 《核技术》
Abstract： Aerospace integrated circuits represent core components of space electronic systems, and anti-radiation hardening is a key technology to ensure the reliable operation of aerospace integrated circuits in the space domain. As the feature sizes of integrated circuits shrink to the nanometer scale, the single-event effect gradually becomes the most critical factor limiting the radiation-hardened performance level of aerospace integrated circuits. In this study, radiation hardened by design is utilized as a method to develop radiation-hardened performance. Based on single-event radiation tests on a heavy ion accelerator, new methods are proposed for the single-event test evaluation of new processes and devices. Consequently, new technique development and radiation effect law research are also undertaken. The effectiveness of the design hardening technology is evaluated, and a single-event radiation damage mechanism is discovered. The proposed technology provides key support for the production of high-reliability and long-lifetime aerospace integrated circuit products.
Subjects: Library Science，Information Science >> Library Science submitted time 2023-08-28
Abstract： Purpose/Significance With the continuous progress of science and technology, library construction must cope with the future changes in information management and knowledge dissemination. As a genre of revelation and contemplation of the future, the library imagery of science fiction is an important reference for the future development of libraries in reality. The thesis aims to explore the revelation of library writing in recent years' science fiction for future library construction. Method/Processes Relying on science fiction databases such as "CSFDB"(Chinese Science Fiction Database) and "Jiu Long Project", we have searched for science fiction with related themes or plots, and analyze the library settings in them to find potential strategies for future library construction by analyzing the new technologies, social services, public space environment, and civilization or cultural values. By analyzing the library settings, we can find out the potential strategies applicable to the construction of libraries in the future. Result/Conclusion The study concluded that the library writing in recent years' science fiction mainly focused on technological revolution and media innovation, public space and social service, information integration and knowledge dissemination, cultural heritage and civilization preservation, etc. The future library construction should creatively transform those experiences and focus on the related fields, so as to let the future libraries play a more active role in the modern society, and to make them the temples of knowledge and the cradles of innovation.
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Subjects: Library Science，Information Science >> Information Science submitted time 2023-04-01 Cooperative journals: 《图书情报工作》
Abstract： [Purpose/significance] In view of the new problems faced by the remote service of electronic resources in university library during the period of epidemic prevention, this paper provides a reference method for improving the remote service ability and service efficiency.[Method/process] Based on the investigation of the practice and literature in university library, this paper analyzed the advantages and disadvantages of the 6 remote service modes,this paper explored the challenges under the background of epidemic situation from the 4 elements of technology, service, resources and librarians of the library, and put forward countermeasures.[Result/conclusion] There will be many kinds of remote services out of school for electronic resources, and united authentication will have the most potential. In the cooperation and game between the library and the data provider, we should attach importance to the rights of readers to obtain resources outside the school. Through this epidemic situation, the remote service ability of library electronic resources outside school will be further improved.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： An important task of enhancing strategic scientific and technological strength is to strengthen national scientific research institutions. From the history of science and the international development, this study discusses the development of the national research institutions and their characteristics as a national strategic strength of science and technology, and discusses the role of Chinese national research institutions in national development, summarizes the achievements and successful experience of the national research institutions for facing the needs of the country, facing the frontier of science and technology, facing the main economic battlefield, and facing the life and health of the people during past ten years. Based on these discussions, policy suggestions are provided for the future development of national scientific research institutions.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： Facing the dynamic international situation and challenges in public emergency, many strategic high-tech fields in China are in desperate need of filling shortcomings, strengthening the weaknesses, and blocking the loopholes. Realizing the complexity of the key scientific issues in the long-term “cut-throat competition” situation, a deeper understanding of the strategic inevitability of improving the systemization of scientific and technological innovation is in a tremendous need. Systematization of scientific and technological innovations presents requirements for outstanding integrity, structure, and organic relevance, which requires continuous advancement and interaction of technology systemization and organization systemization. When focusing on key technologies weaknesses, the technological institutionalization capability should be improved by constructing a systematic and scientific strategy which combines the method of building up longboards and overcoming the shortcomings. Furthermore, the organizational systematic ability should also be strengthened by reinforcing the comprehensive connection between knowledge breakthroughs and business concern. Meanwhile, a complete set of supporting and service system will significantly enhance the efficiency, vitality and resilience of the scientific and technological innovation system. Building a new national system of scientific and technological innovation systems of key technologies with Chinese characteristics will fundamentally strengthen the systematic strategic planning, implement the advantages of the high-tech system, and effectively fill the shortcomings, and strengthen the weaknesses.
Subjects: Mechanics >> Applied Mechanics submitted time 2023-03-20 Cooperative journals: 《应用力学学报》
Abstract： In micro-milling , due to the limitation of machining allowance , the feed per tooth of the millingcutter is very small or even smaller than the internal grain size of the material. When the cutting is carriedout between the grains , it will cause discontinuity in cutting , which will sharply increase the chatter duringthe milling process , cause the quality of the processed surface to decrease , and seriously affect the fatiguelife and performance of the micro-parts. Based on the Voronoi diagram , the paper establishes a polycrystal-line geometric model.'Through the method of simulation and experimental verification , the influence law ofthe cutting edge arc radius , cutting depth and grain size on the residual stress of the machined surface isstudied in detail, and a multiple linear regression model is established.Perform a significance test. The micro-milling experiment was carried out on the superalloy GH4169 with different grain sizes after heattreatment. The residual stress value of the machined surface in the feed direction of the workpiece was meas-ured by X-ray diffraction method , and the experimental value was compared with the predicted value to veri-fy the residual stress prediction model Accuracy. 'The results show that the error distribution is 2.18%o-7.35% ,not more than 10% , which can indicate that the prediction model of residual stress is more accurate.
Subjects: Mechanics >> Applied Mechanics submitted time 2023-03-20 Cooperative journals: 《应用力学学报》
Abstract： Round steel casing-steel fiber cement mortar outsourcing reinforcement RC column is a new typeof reinforcement technology. Steel fiber cement mortar has a significant improvement in toughness,crackresistance and ductility over ondinary concrete mortar ，and the strength and ductility of steel casing rein-forced concrete columns has been improved to a large extent. At present，domestic and internationalresearch on this method mainly focuses on the performance of unpre-damaged components after reinforce-ment，while research on the reinforcement of components with different degrees of damage is still relativelylacking. In this paper，the percentage of the peak load of the pre-loaded ordinary reinforced concrete col-umn is mainly used as the damage index of the column:60% of the ultimate load is primary damage,80% is secondary damage , and 100% is tertiary damage. A total of seven specimens were designed,andthe axial compression test of the damaged columns strengthened with steel casing steel fiber cement mortarwas carried out with steel casing diameter-thickness ratio，damage degree of RC，and dispersion of the pre-damaged columns as the influencing factors. Based on the experimental study , a formula for calculat-ing the axial bearing capacity of reinforced concrete short circular cross-section columns reinforced by steelfiber cement mortar is established.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-19 Cooperative journals: 《金属学报》
Abstract： The crystal structure, phase transformations and magnetic properties for Ni50- xCoxMn39Sn11 (x=0, 2, 4, 6) Heusler alloys have been systematically studied by means of structure and magnetism measurements. The results show that with increase of Co concentration, the martensitic transformation temperatures are obviously decreased, while the Curie temperatures of austenite are gradually increased, and they present different structures at room temperature. At the same time, with increasing Co content, the austenitic magnetism rapidly enhances, while the martensitic magnetism almost keeps unchanged. This leads to a significant improvement of difference magnetization (ΔM) between two phases. For Co content added to x=4, the value of ΔM between two phases achieves about 40 Am2/kg and exhibits magnetic field- induced martensitic transformation. Using strain measurement, the strain behavior related to martensitic transition in Ni50-xCoxMn39Sn11 (x=0, 2, 4) samples was studied. It is found that the phase transition strain reaches 0.17% in Ni46Co4Mn39Sn11 sample. Within the magnetic cycles of 3 T, this sample displays a reproducible magnetostrain in temperature range of 215~235 K. Such a reproducible strain could be ascribed to the fact that a partial martensitic transformation of this sample can be driven by isothermal magnetic field.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-04-24 Cooperative journals: 《计算机应用研究》
Abstract： Aiming at the problems of traditional wolf pack algorithm (WPA) : easy to fall in to local optimal, large computational resource cost and low robustness, propose an improved wolf pack algorithm based on differential evolution (DWPA) . First of all, propose search wolf search factor, maximum number of raid wolves, adaptive siege step size and differential evolution strategy to improve the traditional wolf pack algorithm, which can not only reduce the computational cost of the algorithm but also improve the global search ability. Then, prove the convergence of DWPA applying the Markov process. Finally, conduct optimization test on 13 functions and then compare it with WPA and other 4 algorithms. The test results show that DWPA has great robustness and global search ability, especially has an excellent optimizing ability in multi-peak, high-dimension, indivisible functions.
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