Magnesium alloys are the lightest structural alloys and have attracted substantial research attention in the past two decades. However, their mechanical properties, including ductility and strength, are limited after ...Magnesium alloys are the lightest structural alloys and have attracted substantial research attention in the past two decades. However, their mechanical properties, including ductility and strength, are limited after forming due to the formation of coarse grains and strong texture. This study proposes and proves a new cryogenic-hot forming process concept. Cryogenic deformation is imposed before the hot deformation. The effect of the cryogenic step has been compared with a conventional direct hot deformation process. The mechanical properties, microstructure,and texture of both the novel and conventional process routes have been compared. The cryogenic-hot deformed sample exhibits the highest ductility and fracture strength(ultimate tensile strength: 321 MPa, ductility: 21%) due to effective grain refinement and texture weakening by cryogenically formed twin-twin interaction induced recrystallisation. The proposed cryogenic-hot forming process can be a potential innovative manufacturing method for producing high-performance magnesium components.展开更多
Personality prediction on social network has become a hot topic.At present,most studies are using single-task classification/regression machine learning.However,this method ignores the potential association between mu...Personality prediction on social network has become a hot topic.At present,most studies are using single-task classification/regression machine learning.However,this method ignores the potential association between multiple tasks.Also an ideal prediction result is difficult to achieve based on the small scale training data,since it is not easy to get a lot of social network data with personality label samples.In this paper,a robust multi-task learning method(RMTL)is proposed to predict Big-Five personality on Micro-blog.We aim to learn five tasks simultaneously by extracting and utilizing appropriate shared information among multiple tasks as well as identifying irrelevant tasks.For a set of Sina Micro-blog users’information and personality labeled data retrieved by questionnaire,we validate the RMTL method by comparing it with 4 single-task learning methods and the mere multi-task learning.Our experiment demonstrates that the proposed RMTL can improve the precision rate,recall rate of the prediction and F value.展开更多
The interlayer bonding properties are normally unsatisfying for 3D printed composites owing to the layer-by-layer formation process.In this study,low-pressure annealing was performed on 3D printed carbon fiber reinfor...The interlayer bonding properties are normally unsatisfying for 3D printed composites owing to the layer-by-layer formation process.In this study,low-pressure annealing was performed on 3D printed carbon fiber reinforced polyether ether ketone(CF/PEEK)to improve the interlayer bonding strength.The effects of annealing parameters on the mechanical properties and microstructure were studied.The results showed that the interlaminar shear strength(ILSS)of CF/PEEK improved by up to 55.4%after annealing.SEM and𝜇-CT were also applied to reveal the reinforcing mechanism.This improvement could mainly be attributed to the increased crystallinity of the CF/PEEK after annealing.Additionally,annealing reduced the porosity of the printed CF/PEEK and improved the fiber-resin interface.This resulted in a reduction in the stress concentration areas during loading,thereby enhancing the interlayer bonding strength of CF/PEEK.展开更多
The technology of Covert Channel is often used for communications between computers and the Internet with high sensitivity or security levels.Presently,some research were carried out on covert channel using computer s...The technology of Covert Channel is often used for communications between computers and the Internet with high sensitivity or security levels.Presently,some research were carried out on covert channel using computer screen light radiation,speakers,electromagnetic leakage,etc.In this paper,the technology of SoundHammer is studied.It is a technical bridgeware that use acoustic waves to transmit data from sound device into an air-gapped network.Firstly,an idea was proposed for data transmission by covert channel through acoustic waves.Then,this method was validated by experiment and the risks of the air-gapped network were confirmed.Finally,some countermeasures for detecting and eliminating such covert channels were listed.展开更多
基金the financial support from the President’s PhD Scholarship of Imperial College Londonthe funding support by EPSRC under the Grant Agreement EP/R001715/1 on “Light Form: Embedding Materials Engineering in Manufacturing with Light Alloys”。
文摘Magnesium alloys are the lightest structural alloys and have attracted substantial research attention in the past two decades. However, their mechanical properties, including ductility and strength, are limited after forming due to the formation of coarse grains and strong texture. This study proposes and proves a new cryogenic-hot forming process concept. Cryogenic deformation is imposed before the hot deformation. The effect of the cryogenic step has been compared with a conventional direct hot deformation process. The mechanical properties, microstructure,and texture of both the novel and conventional process routes have been compared. The cryogenic-hot deformed sample exhibits the highest ductility and fracture strength(ultimate tensile strength: 321 MPa, ductility: 21%) due to effective grain refinement and texture weakening by cryogenically formed twin-twin interaction induced recrystallisation. The proposed cryogenic-hot forming process can be a potential innovative manufacturing method for producing high-performance magnesium components.
文摘Personality prediction on social network has become a hot topic.At present,most studies are using single-task classification/regression machine learning.However,this method ignores the potential association between multiple tasks.Also an ideal prediction result is difficult to achieve based on the small scale training data,since it is not easy to get a lot of social network data with personality label samples.In this paper,a robust multi-task learning method(RMTL)is proposed to predict Big-Five personality on Micro-blog.We aim to learn five tasks simultaneously by extracting and utilizing appropriate shared information among multiple tasks as well as identifying irrelevant tasks.For a set of Sina Micro-blog users’information and personality labeled data retrieved by questionnaire,we validate the RMTL method by comparing it with 4 single-task learning methods and the mere multi-task learning.Our experiment demonstrates that the proposed RMTL can improve the precision rate,recall rate of the prediction and F value.
基金This work was supported by Basic Strengthening Program of China(Grant No.2021-JCJQ-JJ-0186)National Natural Science Foundation of China(Grant No.52205383)+1 种基金Natural Science Foundation of Jiangsu(Grant Nos.BK20220895&BK20210314)Postdoctoral Science Foundation of China(Grant No.2021M691568).
文摘The interlayer bonding properties are normally unsatisfying for 3D printed composites owing to the layer-by-layer formation process.In this study,low-pressure annealing was performed on 3D printed carbon fiber reinforced polyether ether ketone(CF/PEEK)to improve the interlayer bonding strength.The effects of annealing parameters on the mechanical properties and microstructure were studied.The results showed that the interlaminar shear strength(ILSS)of CF/PEEK improved by up to 55.4%after annealing.SEM and𝜇-CT were also applied to reveal the reinforcing mechanism.This improvement could mainly be attributed to the increased crystallinity of the CF/PEEK after annealing.Additionally,annealing reduced the porosity of the printed CF/PEEK and improved the fiber-resin interface.This resulted in a reduction in the stress concentration areas during loading,thereby enhancing the interlayer bonding strength of CF/PEEK.
基金through grants from the National Natural Science Foundation of China(No.61602491)the University fund of National University of Defense Technology(No.KY19A013)We also would like to thank the Institute of Psychology,Chinese Academy of Sciences for generously supporting our research.
文摘The technology of Covert Channel is often used for communications between computers and the Internet with high sensitivity or security levels.Presently,some research were carried out on covert channel using computer screen light radiation,speakers,electromagnetic leakage,etc.In this paper,the technology of SoundHammer is studied.It is a technical bridgeware that use acoustic waves to transmit data from sound device into an air-gapped network.Firstly,an idea was proposed for data transmission by covert channel through acoustic waves.Then,this method was validated by experiment and the risks of the air-gapped network were confirmed.Finally,some countermeasures for detecting and eliminating such covert channels were listed.