PrFeB magnets, which possess excellent magnetic properties at low temperatures, have important application value as cryogenic permanent magnet undulators for synchrotron radiation sources and free electron lasers. In ...PrFeB magnets, which possess excellent magnetic properties at low temperatures, have important application value as cryogenic permanent magnet undulators for synchrotron radiation sources and free electron lasers. In this research study, several high-performance PrFeB magnets(P42H, P48SH, and P48UH) were prepared, and their performance was comprehensively examined, including evaluations of their magnetic properties,microstructures, uniformity, and stability. Next,their application prospects were analyzed and discussed. In China, the first cryogenic permanent magnet undulators(CPMUs) with P48SH magnets with 18 mm cycle lengths have been developed. When the temperature is 80 K and the gap is 6.0 mm,the magnetic field measurement results of the CPMU showed that the effective magnetic field peak was approximately 0.92 T, yielding an increase of 11.76% relative to operation at 300 K, with an RMS phase error of about 4.99°.展开更多
In recent years,the demands of high traffic transmission motivate the rapid development of wireless access techniques,and it becomes promising to design the fifth generation(5G)wireless networks.Essential requirements...In recent years,the demands of high traffic transmission motivate the rapid development of wireless access techniques,and it becomes promising to design the fifth generation(5G)wireless networks.Essential requirements for 5G involve higher traffic volume,indoor or hotspot traffic,and spectrum,energy,and cost efficien-展开更多
The ever increasing wireless data services, such asimaging, video, audio, multimedia, etc., have de-mands for the very high speed wireless communicationsand network, which are unfortunately a bottleneck whencombining ...The ever increasing wireless data services, such asimaging, video, audio, multimedia, etc., have de-mands for the very high speed wireless communicationsand network, which are unfortunately a bottleneck whencombining with the wireline core network. Users＇ arenow expecting high quality of experience with low-costdevices, ubiquitous connectivity, energy efficiency, highreliability, or even ultra-low latency if a vehicle terminalis applied.展开更多
Just as Dickens wrote,it is the best of times,it is the worst of times.Ever increasing traffic demands will bring us into the era of 5G.Vast of unprecedented or even unanticipated fancy wireless applications will defi...Just as Dickens wrote,it is the best of times,it is the worst of times.Ever increasing traffic demands will bring us into the era of 5G.Vast of unprecedented or even unanticipated fancy wireless applications will definitely change our life.Regarding the beautiful visions promised by 5G,meanwhile the wireless engineers are faced with unprecedented challenges and pressures for realizing much higher spectrum efficiency and展开更多
India's great power dream has a long history and has borne the expectations of several generations of Indian political elites after its independence. Overseas Indians are highly valued by the Indian government due...India's great power dream has a long history and has borne the expectations of several generations of Indian political elites after its independence. Overseas Indians are highly valued by the Indian government due to their vast resources and special status as a bridge between their residence countries and India. After the end of the Cold War, the Indian government began to consider overseas Indians as an important factor of its human resources and satisfied several demands by establishing relevant institutions, formulating relevant policies, and revising relevant laws. In this manner, they achieved the objective of leveraging overseas Indians. This strategic adjustment is an important part of the new overall development strategy and external strategy, which can be described as key to India's development breakthrough and rapid emergence. However, the current Indian Diaspora is relatively negative for the following reasons: utilitarian Indian Diaspora strategy, the lack of a clear understanding of the home country or nationality, the rotation of Indian political parties, and the lack of sustainability of the Indian Diaspora strategy.展开更多
Surface nanocrystallization by mechanical attrition was used to enhance the chemical vapor deposition process.An aluminum(Al)diffusion coating was produced on AZ91 Mg alloy surface.This process was conducted at a rela...Surface nanocrystallization by mechanical attrition was used to enhance the chemical vapor deposition process.An aluminum(Al)diffusion coating was produced on AZ91 Mg alloy surface.This process was conducted at a relatively low temperature(400◦C)for a short time of 120 min.The results indicated that a continuous and dense Mg17Al12 intermetallic coating with a thickness of∼8µm formed on the Mg alloy substrate.Almost no corrosion was observed after the coated samples were immersed in 3 wt%NaCl solution for 6 h,reflecting a relatively good corrosion resistance.The formation mechanism of the Al diffusion coating is discussed based on the experimental results.展开更多
基金supported by project of the State Key Lab of Advanced Metals and Materials(No.2016-Z03)
文摘PrFeB magnets, which possess excellent magnetic properties at low temperatures, have important application value as cryogenic permanent magnet undulators for synchrotron radiation sources and free electron lasers. In this research study, several high-performance PrFeB magnets(P42H, P48SH, and P48UH) were prepared, and their performance was comprehensively examined, including evaluations of their magnetic properties,microstructures, uniformity, and stability. Next,their application prospects were analyzed and discussed. In China, the first cryogenic permanent magnet undulators(CPMUs) with P48SH magnets with 18 mm cycle lengths have been developed. When the temperature is 80 K and the gap is 6.0 mm,the magnetic field measurement results of the CPMU showed that the effective magnetic field peak was approximately 0.92 T, yielding an increase of 11.76% relative to operation at 300 K, with an RMS phase error of about 4.99°.
文摘In recent years,the demands of high traffic transmission motivate the rapid development of wireless access techniques,and it becomes promising to design the fifth generation(5G)wireless networks.Essential requirements for 5G involve higher traffic volume,indoor or hotspot traffic,and spectrum,energy,and cost efficien-
文摘The ever increasing wireless data services, such asimaging, video, audio, multimedia, etc., have de-mands for the very high speed wireless communicationsand network, which are unfortunately a bottleneck whencombining with the wireline core network. Users＇ arenow expecting high quality of experience with low-costdevices, ubiquitous connectivity, energy efficiency, highreliability, or even ultra-low latency if a vehicle terminalis applied.
文摘Just as Dickens wrote,it is the best of times,it is the worst of times.Ever increasing traffic demands will bring us into the era of 5G.Vast of unprecedented or even unanticipated fancy wireless applications will definitely change our life.Regarding the beautiful visions promised by 5G,meanwhile the wireless engineers are faced with unprecedented challenges and pressures for realizing much higher spectrum efficiency and
基金the periodical achievement of the United Front Top Think Tank project of the Central Institute of Socialism (No. ZK20210130)the Fundamental Research Funds for the Central Universities (No. FRFf-MP-20-42)。
文摘India's great power dream has a long history and has borne the expectations of several generations of Indian political elites after its independence. Overseas Indians are highly valued by the Indian government due to their vast resources and special status as a bridge between their residence countries and India. After the end of the Cold War, the Indian government began to consider overseas Indians as an important factor of its human resources and satisfied several demands by establishing relevant institutions, formulating relevant policies, and revising relevant laws. In this manner, they achieved the objective of leveraging overseas Indians. This strategic adjustment is an important part of the new overall development strategy and external strategy, which can be described as key to India's development breakthrough and rapid emergence. However, the current Indian Diaspora is relatively negative for the following reasons: utilitarian Indian Diaspora strategy, the lack of a clear understanding of the home country or nationality, the rotation of Indian political parties, and the lack of sustainability of the Indian Diaspora strategy.
文摘Surface nanocrystallization by mechanical attrition was used to enhance the chemical vapor deposition process.An aluminum(Al)diffusion coating was produced on AZ91 Mg alloy surface.This process was conducted at a relatively low temperature(400◦C)for a short time of 120 min.The results indicated that a continuous and dense Mg17Al12 intermetallic coating with a thickness of∼8µm formed on the Mg alloy substrate.Almost no corrosion was observed after the coated samples were immersed in 3 wt%NaCl solution for 6 h,reflecting a relatively good corrosion resistance.The formation mechanism of the Al diffusion coating is discussed based on the experimental results.
