This research proposes a simple and practical method to make low-stray-light gratings, where the substrate shifts about a 1 mm distance in the direction parallel or perpendicular to the exposure interference fringes. ...This research proposes a simple and practical method to make low-stray-light gratings, where the substrate shifts about a 1 mm distance in the direction parallel or perpendicular to the exposure interference fringes. When the substrate shifts, a reference grating next to the substrate is used to adjust in real time the phase of the exposure interference fringes relative to the substrate. Shifting eliminates the exposure defects and therefore decreases the stray light of gratings. Several gratings are successfully made by using this method, which have straighter grooves,smoother surfaces, and lower stray light than gratings made in conventional interference lithography.展开更多
Silver nanowire(Ag NW)has been considered as the promising building block for the fabrication of transparent electromagnetic interference(EMI)shielding films.However,the practical application of Ag NW-based EMI shield...Silver nanowire(Ag NW)has been considered as the promising building block for the fabrication of transparent electromagnetic interference(EMI)shielding films.However,the practical application of Ag NW-based EMI shielding films has been restricted due to the unsatisfactory stability of Ag NW.Herein,we proposed a reduced graphene oxide(rGO)decorated Ag NW film,which realizes a seamless integration of optical transparency,highly efficient EMI shielding,reliable durability and stability.The Ag NW constructs a highly transparent and conductive network,and the rGO provides additional conductive path,showing a superior EMI shielding effectiveness(SE)of 33.62 dB at transmittance of 81.9%.In addition,the top rGO layer enables the hybrid film with reliable durability and chemical stability,which can maintain 96%and 90%EMI SE after 1000 times bending cycles at radius of 2 mm and exposure in air for 80 days.Furthermore,the rGO/Ag NW films also possess fast thermal response and heating stability,making them highly applicable in wearable devices.The synergy of Ag NW and rGO grants the hybrid EMI shielding film multiple desired functions and meanwhile overcomes the shortcomings of Ag NW.This work provides a reference for preparing multifunctional integrated transparent EMI shielding film.展开更多
Engineering ceramics with high strength,toughness and electromagnetic interference(EMI)shielding effectiveness(SE)are highly desirable as electromagnetic protecting material in harsh environment.Herein,we show that bo...Engineering ceramics with high strength,toughness and electromagnetic interference(EMI)shielding effectiveness(SE)are highly desirable as electromagnetic protecting material in harsh environment.Herein,we show that both excellent mechanical and EMI shielding performance can be realized in alumina composites embedded with highly aligned reduced graphene oxide(RGO),which are readily prepared via sintering of core-shell structured RGO@Al_(2)O_(3)nanoplates with pressure.Compared to monolithic Al_(2)O_(3),the highly aligned RGO/Al_(2)O_(3)composites show simultaneously improved strength and toughness up to~26.1%and~60.2%,respectively.The steeply rising R-curve behavior proves the better crack tolerance in the highly aligned structure with respect to randomly oriented one.Moreover,the RGO/Al_(2)O_(3)composites also exhibit a high specific EMI SE reaching~34 dB/mm in K band,due to the reflection and highly enhanced absorption after percolation in the out-of-plane direction.These findings provide a novel strategy of designing mechanically reliable engineering ceramic for EMI shielding.展开更多
Recently, virtualization has become more and more important in the cloud computing to support efficient flexible resource provisioning. However, performance interference among virtual machines(VMs) has become a challe...Recently, virtualization has become more and more important in the cloud computing to support efficient flexible resource provisioning. However, performance interference among virtual machines(VMs) has become a challenge which may affect the effectiveness of resource provisioning. In a virtual cluster which runs the Map Reduce applications, the performance interference can also affect the performance of the Map and Reduce tasks and thus cause a performance degradation of the Map Reduce job. Accordingly, this paper presents a Map Reduce scheduling framework to mitigate this performance degradation caused by the performance interference. The framework includes a performance interference prediction module and an interference aware scheduling algorithm. To verify its effectiveness, we have done a set of experiments on a 24-node virtual Map Reduce cluster. The experiments illustrate that the proposed framework can achieve a performance improvement in the virtualized environment compared with other Map Reduce schedulers.展开更多
In this paper, the complexity and performance of the Auxiliary Vector (AV) based reduced-rank filtering are addressed. The AV filters presented in the previous papers have the general form of the sum of the signature ...In this paper, the complexity and performance of the Auxiliary Vector (AV) based reduced-rank filtering are addressed. The AV filters presented in the previous papers have the general form of the sum of the signature vector of the desired signal and a set of weighted AVs,which can be classified as three categories according to the orthogonality of their AVs and the optimality of the weight coefficients of the AVs. The AV filter with orthogonal AVs and optimal weight coefficients has the best performance, but requires considerable computational complexity and suffers from the numerical unstable operation. In order to reduce its computational load while keeping the superior performance, several low complexity algorithms are proposed to efficiently calculate the AVs and their weight coefficients. The diagonal loading technique is also introduced to solve the numerical unstability problem without complexity increase. The performance of the three types of AV filters is also compared through their application to Direct Sequence Code Division Multiple Access (DS-CDM A) systems for interference suppression.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.51427805
文摘This research proposes a simple and practical method to make low-stray-light gratings, where the substrate shifts about a 1 mm distance in the direction parallel or perpendicular to the exposure interference fringes. When the substrate shifts, a reference grating next to the substrate is used to adjust in real time the phase of the exposure interference fringes relative to the substrate. Shifting eliminates the exposure defects and therefore decreases the stray light of gratings. Several gratings are successfully made by using this method, which have straighter grooves,smoother surfaces, and lower stray light than gratings made in conventional interference lithography.
基金Financial support from National Nature Science Foundation of China(51971111)the Foundation of Graduate Innovation Center in NUAA(kfjj20200602)is gratefully acknowledgedOpen access funding provided by Shanghai Jiao Tong University
文摘Silver nanowire(Ag NW)has been considered as the promising building block for the fabrication of transparent electromagnetic interference(EMI)shielding films.However,the practical application of Ag NW-based EMI shielding films has been restricted due to the unsatisfactory stability of Ag NW.Herein,we proposed a reduced graphene oxide(rGO)decorated Ag NW film,which realizes a seamless integration of optical transparency,highly efficient EMI shielding,reliable durability and stability.The Ag NW constructs a highly transparent and conductive network,and the rGO provides additional conductive path,showing a superior EMI shielding effectiveness(SE)of 33.62 dB at transmittance of 81.9%.In addition,the top rGO layer enables the hybrid film with reliable durability and chemical stability,which can maintain 96%and 90%EMI SE after 1000 times bending cycles at radius of 2 mm and exposure in air for 80 days.Furthermore,the rGO/Ag NW films also possess fast thermal response and heating stability,making them highly applicable in wearable devices.The synergy of Ag NW and rGO grants the hybrid EMI shielding film multiple desired functions and meanwhile overcomes the shortcomings of Ag NW.This work provides a reference for preparing multifunctional integrated transparent EMI shielding film.
基金supported by the National Natural Science Foundation of China(Nos.52122203,51972053,and 9163204)Innovation Program of Shanghai Municipal Education Commission(2023ZKZD43)sponsored by Shanghai Sailing Program(No.22YF1400300).
文摘Engineering ceramics with high strength,toughness and electromagnetic interference(EMI)shielding effectiveness(SE)are highly desirable as electromagnetic protecting material in harsh environment.Herein,we show that both excellent mechanical and EMI shielding performance can be realized in alumina composites embedded with highly aligned reduced graphene oxide(RGO),which are readily prepared via sintering of core-shell structured RGO@Al_(2)O_(3)nanoplates with pressure.Compared to monolithic Al_(2)O_(3),the highly aligned RGO/Al_(2)O_(3)composites show simultaneously improved strength and toughness up to~26.1%and~60.2%,respectively.The steeply rising R-curve behavior proves the better crack tolerance in the highly aligned structure with respect to randomly oriented one.Moreover,the RGO/Al_(2)O_(3)composites also exhibit a high specific EMI SE reaching~34 dB/mm in K band,due to the reflection and highly enhanced absorption after percolation in the out-of-plane direction.These findings provide a novel strategy of designing mechanically reliable engineering ceramic for EMI shielding.
基金supported in part by the National Key Technology R&D Program of the Ministry of Science and Technology (2015BAH09F02, 2015BAH47F03)National Natural Science Foundation of China(60903008,61073062)the Fundamental Research Funds for the Central Universities(N130417002, N130404011)
文摘Recently, virtualization has become more and more important in the cloud computing to support efficient flexible resource provisioning. However, performance interference among virtual machines(VMs) has become a challenge which may affect the effectiveness of resource provisioning. In a virtual cluster which runs the Map Reduce applications, the performance interference can also affect the performance of the Map and Reduce tasks and thus cause a performance degradation of the Map Reduce job. Accordingly, this paper presents a Map Reduce scheduling framework to mitigate this performance degradation caused by the performance interference. The framework includes a performance interference prediction module and an interference aware scheduling algorithm. To verify its effectiveness, we have done a set of experiments on a 24-node virtual Map Reduce cluster. The experiments illustrate that the proposed framework can achieve a performance improvement in the virtualized environment compared with other Map Reduce schedulers.
文摘In this paper, the complexity and performance of the Auxiliary Vector (AV) based reduced-rank filtering are addressed. The AV filters presented in the previous papers have the general form of the sum of the signature vector of the desired signal and a set of weighted AVs,which can be classified as three categories according to the orthogonality of their AVs and the optimality of the weight coefficients of the AVs. The AV filter with orthogonal AVs and optimal weight coefficients has the best performance, but requires considerable computational complexity and suffers from the numerical unstable operation. In order to reduce its computational load while keeping the superior performance, several low complexity algorithms are proposed to efficiently calculate the AVs and their weight coefficients. The diagonal loading technique is also introduced to solve the numerical unstability problem without complexity increase. The performance of the three types of AV filters is also compared through their application to Direct Sequence Code Division Multiple Access (DS-CDM A) systems for interference suppression.
