HT7U is a large fusion experimental device. It will be built in the Institute of Plasma Physics of Chinese Academy of Sciences. The mission of HT-7U is to develop the scientific basis for a continuously operating toka...HT7U is a large fusion experimental device. It will be built in the Institute of Plasma Physics of Chinese Academy of Sciences. The mission of HT-7U is to develop the scientific basis for a continuously operating tokama-k fusion reactor. This paper describes only a toroidal field (TF) superconducting magnet system of HT7U. In this paper, design criteria of conductor and stability analysis, coil winding and support structure design of magnet system, mechanical calculation and stress analysis, heat load evaluation are given.展开更多
The slogan of“Combination of medicine and engineering”proposed in“Made in China 2025”has aroused great attention to higher engineering education.However,it is a difficult problem and challenge for schools and educ...The slogan of“Combination of medicine and engineering”proposed in“Made in China 2025”has aroused great attention to higher engineering education.However,it is a difficult problem and challenge for schools and educators to effectively adapt to the economic and social development,train new medical and engineering talents,and explore and cultivate new subject growth points.In order to deal with engineering change and a new round of scientific and technological revolution,facing the challenge of new engineering construction.This paper will combine the reality and characteristics of colleges and universities,analyze the problems existing in the current medical engineering cross-graduate training,and put forward countermeasures and suggestions to promote the progress and development of science and technology in colleges and universities.展开更多
An optically levitated nanoparticle in a vacuum provides an ideal platform for ultra-precision measurements and fundamental physics studies because of the exceptionally high-quality factor and rich motion modes,which ...An optically levitated nanoparticle in a vacuum provides an ideal platform for ultra-precision measurements and fundamental physics studies because of the exceptionally high-quality factor and rich motion modes,which can be engineered by manipulating the optical field and the geometry of the nanoparticle.Nanofabrication technology with the ability to create arbitrary nanostructure arrays offers a precise way of engineering the optical field and the geometry of the nanoparticle.Here,for the first time,we optically levitate and rotate a nanofabricated nanorod via a nanofabricated a-Si metalens which strongly focuses a 1550 nm laser beam with a numerical aperture of 0.953.By manipulating the laser beam’s polarization,the levitated nanorod’s translation frequencies can be tuned,and the spin rotation mode can be switched on and off.Then,we showed the control of rotational frequency by changing the laser beam’s intensity and polarization as well as the air pressure.Finally,a MHz spin rotation frequency of the nanorod is achieved in the experiment.This is the first demonstration of controlled optical spin in a metalens-based compact optical levitation system.Our research holds promise for realizing scalable on-chip integrated optical levitation systems.展开更多
As oil and gas exploration continues to progress into deeper and unconventional reservoirs,the likelihood of kick risk increases,making kick warning a critical factor in ensuring drilling safety and efficiency.Due to ...As oil and gas exploration continues to progress into deeper and unconventional reservoirs,the likelihood of kick risk increases,making kick warning a critical factor in ensuring drilling safety and efficiency.Due to the scarcity of kick samples,traditional supervised models perform poorly,and significant fluctuations in field data lead to high false alarm rates.This study proposes an unsupervised graph autoencoder(GAE)-based kick warning method,which effectively reduces false alarms by eliminating the influence of field engineer operations and incorporating real-time model updates.The method utilizes the GAE model to process time-series data during drilling,accurately identifying kick risk while overcoming challenges related to small sample sizes and missing features.To further reduce false alarms,the weighted dynamic time warping(WDTW)algorithm is introduced to identify fluctuations in logging data caused by field engineer operations during drilling,with real-time updates applied to prevent normal conditions from being misclassified as kick risk.Experimental results show that the GAE-based kick warning method achieves an accuracy of 92.7%and significantly reduces the false alarm rate.The GAE model continues to operate effectively even under conditions of missing features and issues kick warnings 4 min earlier than field engineers,demonstrating its high sensitivity and robustness.After integrating the WDTW algorithm and real-time updates,the false alarm rate is reduced from 17.3%to 5.6%,further improving the accuracy of kick warnings.The proposed method provides an efficient and reliable approach for kick warning in drilling operations,offering strong practical value and technical support for the intelligent management of future drilling operations.展开更多
Since the invention of lasers,spatial-light-modulated laser processing has become a powerful tool for various applications.It enables multidimensional and dynamic modulation of the laser beam,which significantly impro...Since the invention of lasers,spatial-light-modulated laser processing has become a powerful tool for various applications.It enables multidimensional and dynamic modulation of the laser beam,which significantly improves the processing efficiency,accuracy,and flexibility,and presents wider prospects over traditional mechanical technologies for machining three-dimensional,hard,brittle,or transparent materials.In this review,we introduce:(1)The role of spatial light modulation technology in the development of femtosecond laser manufacturing;(2)the structured light generated by spatial light modulation and its generation methods;and(3)representative applications of spatial-light-modulated femtosecond laser manufacturing,including aberration correction,parallel processing,focal field engineering,and polarization control.Finally,we summarize the present challenges in the field and possible future research.展开更多
Metamaterials have earned their name with extraordinary properties such as negative refractive index and invisibility cloaking. With over 15 years of research and development, metamaterials show their debut in real wo...Metamaterials have earned their name with extraordinary properties such as negative refractive index and invisibility cloaking. With over 15 years of research and development, metamaterials show their debut in real world applications, especially in the areas of telecommunication, sensing, aerospace & defense, optics and medical instrumentation. In the meanwhile, metamaterials are expanding their concept in areas beyond electromagnetics. In this paper, the authors would like to focus on the research and applications in telecommunication and sensing. Octave-bandwidth horn antennas, flat-panel satellite antennas and air-borne holographic satellite antennas are all fabulous examples of clever implementation that bring metamaterials into practical devices. We would like to discuss the features that differentiate metamaterials from conventional counterparts in case studies. With the advancement in design, manufacturing, packaging, detection and testing, more sophisticated features are expected in the telecommunication, sensing, and beyond.展开更多
文摘HT7U is a large fusion experimental device. It will be built in the Institute of Plasma Physics of Chinese Academy of Sciences. The mission of HT-7U is to develop the scientific basis for a continuously operating tokama-k fusion reactor. This paper describes only a toroidal field (TF) superconducting magnet system of HT7U. In this paper, design criteria of conductor and stability analysis, coil winding and support structure design of magnet system, mechanical calculation and stress analysis, heat load evaluation are given.
文摘The slogan of“Combination of medicine and engineering”proposed in“Made in China 2025”has aroused great attention to higher engineering education.However,it is a difficult problem and challenge for schools and educators to effectively adapt to the economic and social development,train new medical and engineering talents,and explore and cultivate new subject growth points.In order to deal with engineering change and a new round of scientific and technological revolution,facing the challenge of new engineering construction.This paper will combine the reality and characteristics of colleges and universities,analyze the problems existing in the current medical engineering cross-graduate training,and put forward countermeasures and suggestions to promote the progress and development of science and technology in colleges and universities.
文摘An optically levitated nanoparticle in a vacuum provides an ideal platform for ultra-precision measurements and fundamental physics studies because of the exceptionally high-quality factor and rich motion modes,which can be engineered by manipulating the optical field and the geometry of the nanoparticle.Nanofabrication technology with the ability to create arbitrary nanostructure arrays offers a precise way of engineering the optical field and the geometry of the nanoparticle.Here,for the first time,we optically levitate and rotate a nanofabricated nanorod via a nanofabricated a-Si metalens which strongly focuses a 1550 nm laser beam with a numerical aperture of 0.953.By manipulating the laser beam’s polarization,the levitated nanorod’s translation frequencies can be tuned,and the spin rotation mode can be switched on and off.Then,we showed the control of rotational frequency by changing the laser beam’s intensity and polarization as well as the air pressure.Finally,a MHz spin rotation frequency of the nanorod is achieved in the experiment.This is the first demonstration of controlled optical spin in a metalens-based compact optical levitation system.Our research holds promise for realizing scalable on-chip integrated optical levitation systems.
基金Youth Foundation of National Natural Science Foundation of China (No. 52204020)Distinguished Young Foundation of National Natural Science Foundation of China (No. 52125401).
文摘As oil and gas exploration continues to progress into deeper and unconventional reservoirs,the likelihood of kick risk increases,making kick warning a critical factor in ensuring drilling safety and efficiency.Due to the scarcity of kick samples,traditional supervised models perform poorly,and significant fluctuations in field data lead to high false alarm rates.This study proposes an unsupervised graph autoencoder(GAE)-based kick warning method,which effectively reduces false alarms by eliminating the influence of field engineer operations and incorporating real-time model updates.The method utilizes the GAE model to process time-series data during drilling,accurately identifying kick risk while overcoming challenges related to small sample sizes and missing features.To further reduce false alarms,the weighted dynamic time warping(WDTW)algorithm is introduced to identify fluctuations in logging data caused by field engineer operations during drilling,with real-time updates applied to prevent normal conditions from being misclassified as kick risk.Experimental results show that the GAE-based kick warning method achieves an accuracy of 92.7%and significantly reduces the false alarm rate.The GAE model continues to operate effectively even under conditions of missing features and issues kick warnings 4 min earlier than field engineers,demonstrating its high sensitivity and robustness.After integrating the WDTW algorithm and real-time updates,the false alarm rate is reduced from 17.3%to 5.6%,further improving the accuracy of kick warnings.The proposed method provides an efficient and reliable approach for kick warning in drilling operations,offering strong practical value and technical support for the intelligent management of future drilling operations.
基金This work was supported by the National Key R&D Program of China(Grant No.2021YFB2802000)the National Natural Science Foundation of China(Grant Nos.61827826,62175086,62131018)+1 种基金the Natural Science Foundation of Jilin Province(Grant No.20220101107JC)the Education Department of Jilin Province(Grant No.JJKH20221003KJ).
文摘Since the invention of lasers,spatial-light-modulated laser processing has become a powerful tool for various applications.It enables multidimensional and dynamic modulation of the laser beam,which significantly improves the processing efficiency,accuracy,and flexibility,and presents wider prospects over traditional mechanical technologies for machining three-dimensional,hard,brittle,or transparent materials.In this review,we introduce:(1)The role of spatial light modulation technology in the development of femtosecond laser manufacturing;(2)the structured light generated by spatial light modulation and its generation methods;and(3)representative applications of spatial-light-modulated femtosecond laser manufacturing,including aberration correction,parallel processing,focal field engineering,and polarization control.Finally,we summarize the present challenges in the field and possible future research.
基金supported by Guangdong Innovative Research Team Program(Grant No.2009010005)State Key Laboratory of Meta-RF Electromagnetic Modulation Technology,Shenzhen Innovation P&D Team Program(Peacock Plan)(Grant No.KQE201106020031A)Guangdong Natural Science Funds for Distinguished Young Scholar(Grant No.S20120011253)“Metamaterial Design Method and System”
文摘Metamaterials have earned their name with extraordinary properties such as negative refractive index and invisibility cloaking. With over 15 years of research and development, metamaterials show their debut in real world applications, especially in the areas of telecommunication, sensing, aerospace & defense, optics and medical instrumentation. In the meanwhile, metamaterials are expanding their concept in areas beyond electromagnetics. In this paper, the authors would like to focus on the research and applications in telecommunication and sensing. Octave-bandwidth horn antennas, flat-panel satellite antennas and air-borne holographic satellite antennas are all fabulous examples of clever implementation that bring metamaterials into practical devices. We would like to discuss the features that differentiate metamaterials from conventional counterparts in case studies. With the advancement in design, manufacturing, packaging, detection and testing, more sophisticated features are expected in the telecommunication, sensing, and beyond.
