Optical data storage(ODS)is a low-cost and high-durability counterpart of traditional electronic or mag-netic storage.As a means of enhancing ODS capacity,the multiple recording layer(MRL)method is more promising than...Optical data storage(ODS)is a low-cost and high-durability counterpart of traditional electronic or mag-netic storage.As a means of enhancing ODS capacity,the multiple recording layer(MRL)method is more promising than other approaches such as reducing the recording volume and multiplexing technology.However,the architecture of current MRLs is identical to that of recording data into physical layers with rigid space,which leads to either severe interlayer crosstalk or finite recording layers constrained by the short working distances of the objectives.Here,we propose the concept of hybrid-layer ODS,which can record optical information into a physical layer and multiple virtual layers by using high-orthogonality random meta-channels.In the virtual layer,32 images are experimentally reconstructed through holog-raphy,where their holographic phases are encoded into 16 printed images and complementary images in the physical layer,yielding a capacity of 2.5 Tbit cm^(-3).A higher capacity is achievable with more virtual layers,suggesting hybrid-layer ODS as a possible candidate for next-generation ODS.展开更多
A novel virtual material layer model based on the fractal theory was proposed to predict the natural frequencies of carbon fiber reinforced plastic composite bolted joints.Rough contact surfaces of composite bolted jo...A novel virtual material layer model based on the fractal theory was proposed to predict the natural frequencies of carbon fiber reinforced plastic composite bolted joints.Rough contact surfaces of composite bolted joints are modeled with this new proposed approach.Numerical and experimental modal analyses were conducted to validate the effectiveness of the proposed model.A good consistence is noted between the numerical and experimental results.To demonstrate the necessity of accurately modeling the rough contact surfaces in the prediction of natural frequencies,virtual material layer model was compared with the widely used traditional model based on the Master-Slave contact algorithm and experiments,respectively.Results show that the proposed model has a better agreement with experiments than the widely used traditional model(the prediction accuracy is raised by 8.77%when the pre-tightening torque is 0.5 N·m).Real contact area ratio A*of three different virtual material layers were calculated.Value of A*were discussed with dimensionless load P*,fractal dimension D and fractal roughness G.This work provides a new efficient way for accurately modeling the rough contact surfaces and predicting the natural frequencies of composite bolted joints,which can be used to help engineers in the dynamic design of composite materials.展开更多
为探究如何提高共享储能电站参与低碳调度的能力,针对传统储能存在利用率低、成本高的问题,提出虚拟电厂(Virtual Power Plant,VPP)与共享储能电站协同运行的低碳调度策略.首先,建立含有共享储能的多VPP框架,并从冷、热、电三个维度构...为探究如何提高共享储能电站参与低碳调度的能力,针对传统储能存在利用率低、成本高的问题,提出虚拟电厂(Virtual Power Plant,VPP)与共享储能电站协同运行的低碳调度策略.首先,建立含有共享储能的多VPP框架,并从冷、热、电三个维度构建设备模型.然后,提出一种考虑碳排放的动态电价与共享储能联合的多VPP双层优化调度策略:上层以多VPP的运行成本最低为目标,综合考量VPP与共享储能电站的交互和机组出力,得到系统的碳量比例,为下层调度提供指导电价;下层以共享储能电站的收益最大为目标,在上层电价的指导下,引导其为多VPP服务;以上层成本减下层收益最小为收敛目标,利用纵横交叉算法求解最终调度策略.最后,算例仿真结果表明,动态电价策略可以在降低整个系统的碳排放量的同时提高共享储能电站的充放电收益.展开更多
Clustering or connected dominating set (CDS) both approaches can establish a virtual backbone (VB) in wireless sensor networks (WSNs) or wireless mesh networks (WMNs). Each cluster consisting of a cluster head (CH) an...Clustering or connected dominating set (CDS) both approaches can establish a virtual backbone (VB) in wireless sensor networks (WSNs) or wireless mesh networks (WMNs). Each cluster consisting of a cluster head (CH) and its neighboring nodes can form a dominating set. After some bridging nodes were selected, cluster heads (CHs) connected through these bridging nodes naturally formed a CDS. Although CDS provides obvious backbone architecture, however, the number of cluster heads and bridging nodes may be too large, this may cause the loss of advantages of virtual backbone. When we effectively reduce their numbers, more effectively WCDS (Weakly Connected Dominating Set) can be fining out. Some essential topics on constructing WCDS-based VB in WSN/WMN are discussed in this paper. From the point of view of three different protocol layers, including network (NWK) layer, MAC layer, and physical (PHY) layer, we explore their cross-layer research topics and design algorithms. For NWK layer, area-based WCDS algorithms and routing strategies including via VB and not via VB are discussed. For MAC layer, a WCDS-based energy-efficient MAC protocol is presented. For PHY layer, battery-aware alternative VB selections and sensor nodes with different transmission ranges are addressed.展开更多
In this paper, we present a magnetocardiogram （MCG） simulation study using the boundary element method （BEM） and based on the virtual heart model and the realistic human volume conductor model. The different contr...In this paper, we present a magnetocardiogram （MCG） simulation study using the boundary element method （BEM） and based on the virtual heart model and the realistic human volume conductor model. The different contributions of cardiac equivalent source models and volume conductor models to the MCG are deeply and comprehensively investigated. The single dipole source model, the multiple dipoles source model and the equivalent double layer （EDL） source model are analysed and compared with the cardiac equivalent source models. Meanwhile, the effect of the volume conductor model on the MCG combined with these cardiac equivalent sources is investigated. The simulation results demonstrate that the cardiac electrophysiological information will be partly missed when only the single dipole source is taken, while the EDL source is a good option for MCG simulation and the effect of the volume conductor is smallest for the EDL source. Therefore, the EDL source is suitable for the study of MCG forward and inverse problems, and more attention should be paid to it in future MCG studies.展开更多
目的探讨双层探测器光谱CT(DLCT)虚拟平扫(VNC)联合碘图对血管内治疗(EVT)术后早期脑出血与对比剂渗出的鉴别诊断价值。方法回顾性分析EVT术后即刻完成DLCT检查的患者资料。以术后24 h CT/MRI为金标准分为非出血组和出血组,比较两组临...目的探讨双层探测器光谱CT(DLCT)虚拟平扫(VNC)联合碘图对血管内治疗(EVT)术后早期脑出血与对比剂渗出的鉴别诊断价值。方法回顾性分析EVT术后即刻完成DLCT检查的患者资料。以术后24 h CT/MRI为金标准分为非出血组和出血组,比较两组临床资料的差异。测量VNC CT值和碘浓度(IC)值,对VNC CT值和碘图IC值进行多因素二项logistic回归,分析鉴别非出血和出血的独立指标。利用Spearman秩相关检验分析VNC CT值和碘图IC值之间的相关性。采用R统计软件绘制ROC曲线分析,评估VNC、碘图及两者联合的判别效能。结果共97例患者接受DLCT检查,51例(52.6%)各序列均未发现脑内高密度灶,46例(47.4%)发现异常密度灶纳入最终分析。以术后24 h CT/MRI为金标准,最终纳入分析的46例患者中,非出血38例(82.6%),出血8例(17.4%)。组间年龄、性别及治疗方式差异均无统计学意义(P>0.05)。经Spearman秩相关检验结果显示,VNC CT值与碘图IC值呈负相关(r=-0.537,P<0.01)。ROC曲线分析显示,利用VNC CT值诊断对比剂渗出的AUC为0.917(95%CI:0.786~0.999),碘图IC值的AUC为0.878(95%CI:0.719~0.999),两者联合的AUC为0.919(95%CI:0.812~0.999),其中两者联合的AUC明显大于VNC和碘图的AUC(P<0.05)。VNC CT值诊断的截断值为53.6 HU,碘图IC值诊断的截断值为0.605 mg/mL。基于最终纳入分析的46例患者,VNC、碘图及两者联合诊断早期脑出血与对比剂渗出的敏感度分别为88.9%、94.3%、91.4%,特异度分别为94.3%、77.8%、88.9%,准确率分别为90.9%、90.9%、93.2%。结论DLCT的VNC联合碘图可显著提高EVT术后脑出血与对比剂渗出的鉴别诊断准确性,推荐作为常规影像学评估方案。展开更多
基金the National Key Research and Development Program of China(2022YFB3607300)the National Natural Science Foundation of China(62322512 and 12134013)+3 种基金the Chinese Acad-emy of Sciences Project for Young Scientists in Basic Research(YSBR-049)support from the University of Science and Technology of China’s Center for Micro and Nanoscale Research and Fabricationsupported by the China Postdoctoral Science Foundation(2023M743364)supercomputing system in Hefei Advanced Computing Center and the Supercomputing Center of University of Science and Technology of China.
文摘Optical data storage(ODS)is a low-cost and high-durability counterpart of traditional electronic or mag-netic storage.As a means of enhancing ODS capacity,the multiple recording layer(MRL)method is more promising than other approaches such as reducing the recording volume and multiplexing technology.However,the architecture of current MRLs is identical to that of recording data into physical layers with rigid space,which leads to either severe interlayer crosstalk or finite recording layers constrained by the short working distances of the objectives.Here,we propose the concept of hybrid-layer ODS,which can record optical information into a physical layer and multiple virtual layers by using high-orthogonality random meta-channels.In the virtual layer,32 images are experimentally reconstructed through holog-raphy,where their holographic phases are encoded into 16 printed images and complementary images in the physical layer,yielding a capacity of 2.5 Tbit cm^(-3).A higher capacity is achievable with more virtual layers,suggesting hybrid-layer ODS as a possible candidate for next-generation ODS.
基金supported by National Natural Science Foundation of China(grant number 51975472)Intelligent Robotic in Ministry of Science and Technology of the People’s Republic of China(grant number 2017YFB1301703)Shaanxi New Star Plan of Science and Technology(grant number 2019KJXX-063)。
文摘A novel virtual material layer model based on the fractal theory was proposed to predict the natural frequencies of carbon fiber reinforced plastic composite bolted joints.Rough contact surfaces of composite bolted joints are modeled with this new proposed approach.Numerical and experimental modal analyses were conducted to validate the effectiveness of the proposed model.A good consistence is noted between the numerical and experimental results.To demonstrate the necessity of accurately modeling the rough contact surfaces in the prediction of natural frequencies,virtual material layer model was compared with the widely used traditional model based on the Master-Slave contact algorithm and experiments,respectively.Results show that the proposed model has a better agreement with experiments than the widely used traditional model(the prediction accuracy is raised by 8.77%when the pre-tightening torque is 0.5 N·m).Real contact area ratio A*of three different virtual material layers were calculated.Value of A*were discussed with dimensionless load P*,fractal dimension D and fractal roughness G.This work provides a new efficient way for accurately modeling the rough contact surfaces and predicting the natural frequencies of composite bolted joints,which can be used to help engineers in the dynamic design of composite materials.
文摘为探究如何提高共享储能电站参与低碳调度的能力,针对传统储能存在利用率低、成本高的问题,提出虚拟电厂(Virtual Power Plant,VPP)与共享储能电站协同运行的低碳调度策略.首先,建立含有共享储能的多VPP框架,并从冷、热、电三个维度构建设备模型.然后,提出一种考虑碳排放的动态电价与共享储能联合的多VPP双层优化调度策略:上层以多VPP的运行成本最低为目标,综合考量VPP与共享储能电站的交互和机组出力,得到系统的碳量比例,为下层调度提供指导电价;下层以共享储能电站的收益最大为目标,在上层电价的指导下,引导其为多VPP服务;以上层成本减下层收益最小为收敛目标,利用纵横交叉算法求解最终调度策略.最后,算例仿真结果表明,动态电价策略可以在降低整个系统的碳排放量的同时提高共享储能电站的充放电收益.
文摘Clustering or connected dominating set (CDS) both approaches can establish a virtual backbone (VB) in wireless sensor networks (WSNs) or wireless mesh networks (WMNs). Each cluster consisting of a cluster head (CH) and its neighboring nodes can form a dominating set. After some bridging nodes were selected, cluster heads (CHs) connected through these bridging nodes naturally formed a CDS. Although CDS provides obvious backbone architecture, however, the number of cluster heads and bridging nodes may be too large, this may cause the loss of advantages of virtual backbone. When we effectively reduce their numbers, more effectively WCDS (Weakly Connected Dominating Set) can be fining out. Some essential topics on constructing WCDS-based VB in WSN/WMN are discussed in this paper. From the point of view of three different protocol layers, including network (NWK) layer, MAC layer, and physical (PHY) layer, we explore their cross-layer research topics and design algorithms. For NWK layer, area-based WCDS algorithms and routing strategies including via VB and not via VB are discussed. For MAC layer, a WCDS-based energy-efficient MAC protocol is presented. For PHY layer, battery-aware alternative VB selections and sensor nodes with different transmission ranges are addressed.
基金supported by the State Key Development Program for Basic Research of China (Grant Nos. 2007CB512100 and2006CB601007)the National Natural Science Foundation of China (Grant No. 10674006)+2 种基金the National High Technology Research and Development Program of China (Grant No. 2007AA03Z238)China Postdoctoral Science Foundation (Grant No. 20090461376)the Fundamental Research Funds for the Central Universities (Grant No. KYJD09001)
文摘In this paper, we present a magnetocardiogram （MCG） simulation study using the boundary element method （BEM） and based on the virtual heart model and the realistic human volume conductor model. The different contributions of cardiac equivalent source models and volume conductor models to the MCG are deeply and comprehensively investigated. The single dipole source model, the multiple dipoles source model and the equivalent double layer （EDL） source model are analysed and compared with the cardiac equivalent source models. Meanwhile, the effect of the volume conductor model on the MCG combined with these cardiac equivalent sources is investigated. The simulation results demonstrate that the cardiac electrophysiological information will be partly missed when only the single dipole source is taken, while the EDL source is a good option for MCG simulation and the effect of the volume conductor is smallest for the EDL source. Therefore, the EDL source is suitable for the study of MCG forward and inverse problems, and more attention should be paid to it in future MCG studies.
