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DAUNet: Detail-Aware U-Shaped Network for 2D Human Pose Estimation
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作者 Xi Li Yuxin Li +2 位作者 Zhenhua Xiao Zhenghua Huang Lianying Zou 《Computers, Materials & Continua》 SCIE EI 2024年第11期3325-3349,共25页
Human pose estimation is a critical research area in the field of computer vision,playing a significant role in applications such as human-computer interaction,behavior analysis,and action recognition.In this paper,we... Human pose estimation is a critical research area in the field of computer vision,playing a significant role in applications such as human-computer interaction,behavior analysis,and action recognition.In this paper,we propose a U-shaped keypoint detection network(DAUNet)based on an improved ResNet subsampling structure and spatial grouping mechanism.This network addresses key challenges in traditional methods,such as information loss,large network redundancy,and insufficient sensitivity to low-resolution features.DAUNet is composed of three main components.First,we introduce an improved BottleNeck block that employs partial convolution and strip pooling to reduce computational load and mitigate feature loss.Second,after upsampling,the network eliminates redundant features,improving the overall efficiency.Finally,a lightweight spatial grouping attention mechanism is applied to enhance low-resolution semantic features within the feature map,allowing for better restoration of the original image size and higher accuracy.Experimental results demonstrate that DAUNet achieves superior accuracy compared to most existing keypoint detection models,with a mean PCKh@0.5 score of 91.6%on the MPII dataset and an AP of 76.1%on the COCO dataset.Moreover,real-world experiments further validate the robustness and generalizability of DAUNet for detecting human bodies in unknown environments,highlighting its potential for broader applications. 展开更多
关键词 Human pose estimation keypoint detection u-shaped network architecture spatial grouping mechanism
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A U-Shaped Network-Based Grid Tagging Model for Chinese Named Entity Recognition
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作者 Yan Xiang Xuedong Zhao +3 位作者 Junjun Guo Zhiliang Shi Enbang Chen Xiaobo Zhang 《Computers, Materials & Continua》 SCIE EI 2024年第6期4149-4167,共19页
Chinese named entity recognition(CNER)has received widespread attention as an important task of Chinese information extraction.Most previous research has focused on individually studying flat CNER,overlapped CNER,or d... Chinese named entity recognition(CNER)has received widespread attention as an important task of Chinese information extraction.Most previous research has focused on individually studying flat CNER,overlapped CNER,or discontinuous CNER.However,a unified CNER is often needed in real-world scenarios.Recent studies have shown that grid tagging-based methods based on character-pair relationship classification hold great potential for achieving unified NER.Nevertheless,how to enrich Chinese character-pair grid representations and capture deeper dependencies between character pairs to improve entity recognition performance remains an unresolved challenge.In this study,we enhance the character-pair grid representation by incorporating both local and global information.Significantly,we introduce a new approach by considering the character-pair grid representation matrix as a specialized image,converting the classification of character-pair relationships into a pixel-level semantic segmentation task.We devise a U-shaped network to extract multi-scale and deeper semantic information from the grid image,allowing for a more comprehensive understanding of associative features between character pairs.This approach leads to improved accuracy in predicting their relationships,ultimately enhancing entity recognition performance.We conducted experiments on two public CNER datasets in the biomedical domain,namely CMeEE-V2 and Diakg.The results demonstrate the effectiveness of our approach,which achieves F1-score improvements of 7.29 percentage points and 1.64 percentage points compared to the current state-of-the-art(SOTA)models,respectively. 展开更多
关键词 Chinese named entity recognition character-pair relation classification grid tagging u-shaped segmentation network
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Vortex模型对气道管理质控的提示作用
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作者 龚亚红 彭煜 易杰 《麻醉安全与质控》 2024年第5期241-244,共4页
困难气道的处理是气道管理工作中的重要挑战之一,目前许多气道管理协会制定的困难气道管理指南在临床实践中的依从性和可操作性较差,原因包括指南内容复杂以及缺乏具体决策指导。为了提高指南的依从性和执行率,Vortex模型应运而生。Vor... 困难气道的处理是气道管理工作中的重要挑战之一,目前许多气道管理协会制定的困难气道管理指南在临床实践中的依从性和可操作性较差,原因包括指南内容复杂以及缺乏具体决策指导。为了提高指南的依从性和执行率,Vortex模型应运而生。Vortex模型由Nicholas Chrimes于2013年提出,是一种补充现有困难气道管理指南的认知辅助工具,目的在于提供一个简洁的管理思维模型,通过视觉化的漩涡结构帮助气道管理团队成员形成共同的情境认知,从而提高困难气道管理时的沟通和决策能力。本文旨在对Vortex模型的概念、特点及应用方法进行全面的综述,以期对目前临床上气道管理的质控工作提供可借鉴的经验。 展开更多
关键词 气道管理 认知工具 vortex模型
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Effect of mold and core preheating temperature on corrosion resistance of casting Al-12Si alloy U-shaped cooling channel
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作者 Guang-long Li Jie Zhang +3 位作者 Meng-yu Wang Rui-ming Su Yang Cao Ying-dong Qu 《China Foundry》 SCIE CAS CSCD 2023年第3期218-224,共7页
Temperature has an important impact on the corrosion resistance of mold with cooling channels prepared by casting method.The effect of preheating temperature of the mold and the carbon fiber core on the roughness and ... Temperature has an important impact on the corrosion resistance of mold with cooling channels prepared by casting method.The effect of preheating temperature of the mold and the carbon fiber core on the roughness and corrosion resistance of U-shaped cooling channels made of Al-12Si alloy was examined in depth.The experimental results suggest that as the preheating temperature increased from 273 K to 573 K,the roughness of the inner wall of the cooling channel reduced from 96.6μm to 77.0μm.When the preheating temperature continued to increase to 723 K,the roughness increased to 85.3μm.The wetting between the Al melt and the carbon fiber will reduce micro bubbles and waves on the channel wall as the preheating temperature rises,thereby reducing the roughness.However,with the further increase of preheating temperature,it will increase the solidification time of the Al melt.At this time,the carbon fiber and Al melt will take more time to react,which increases the roughness of the channel wall to a certain extent.The results of exfoliation corrosion show that the larger roughness will aggravate exfoliation corrosion.The prolongation of high temperature reaction time between the carbon fiber and the Al melt will lead to the segregation of Si,which is easy to cause intergranular corrosion.Therefore,reasonable preheating temperature has an important impact on the roughness and corrosion resistance of U-shaped cooling channels. 展开更多
关键词 u-shaped cooling channels ROUGHNESS exfoliation corrosion intergranular corrosion
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Orbital angular momentum conversion of acoustic vortex beams via planar lattice coupling
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作者 Qingbang Han Zhipeng Liu +9 位作者 Cheng Yin Simeng Wu Yinlong Luo Zixin Yang Xiuyang Pang Yiqiu Wang Xuefen Kan Yuqiu Zhang Qiang Yu Jian Wu 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第9期413-420,共8页
Orbital angular momentum(OAM)conversion is critical in understanding interactions between a structural sound field and a planar lattice.Herein,we explore the evolution of a monochromatic acoustic vortex beam(AVB)that ... Orbital angular momentum(OAM)conversion is critical in understanding interactions between a structural sound field and a planar lattice.Herein,we explore the evolution of a monochromatic acoustic vortex beam(AVB)that is scattered by a phononic crystal(PnC)or a correlated random lattice.The phenomenon is ascribed to the enhanced orbit–orbit angular momentum coupling induced by the band structure.By modifying the coupling condition,accurate and continuous micromanipulation of AVBs can be achieved,including the transverse/lateral gravity shift,the dynamics of the phase singularities,and the spatial distribution of acoustic pressure,etc.This research provides insight to the inhomogeneous coupling of AVBs with both propagating Bloch waves and localized Anderson modes,and may facilitate development of novel OAM-based acoustic devices for active sound field manipulation. 展开更多
关键词 acoustic vortex beam phononic crystal Anderson localization Imbert-Fedorov effect
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Young's double slit interference with vortex source
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作者 段琦琳 赵鹏飞 +1 位作者 殷玉杭 陈焕阳 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期395-399,共5页
The fast and convenient demultiplex of optical vortex(OV) mode is crucial for its further application. We propose a novel approach that combines classic Young's doublet with an OV source to effectively identify th... The fast and convenient demultiplex of optical vortex(OV) mode is crucial for its further application. We propose a novel approach that combines classic Young's doublet with an OV source to effectively identify the OV mode through the analysis of interference patterns. The interference patterns of the OV source incident on the double slits can be perfectly illustrated by using both the classical double-slit interference method and the Huygens–Fresnel principle. The interference fringes will twist along the negative or positive direction of x axis when topological charge(TC)l>0 or l<0, and the degree of the movement varies with the TC, allowing for a quantitative display of the OV characteristics through the interference patterns. Additionally, we deduce analytically that the zeroth-order interference fringe has a linear relationship with the TC and the vertical position. These findings highlight the ability to identify the OV mode by analyzing the interference patterns produced by Young's doublet. 展开更多
关键词 Young's double slit vortex source inteference patterns
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Numerical Study on the Effect of Vortex Generators on the Aerodynamic Drag of a High-Speed Train
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作者 Tian Li Hao Liang +1 位作者 Zerui Xiang Jiye Zhang 《Fluid Dynamics & Materials Processing》 EI 2024年第2期463-473,共11页
A relatively high aerodynamic drag is an important factor that hinders the further acceleration of high-speed trains.Using the shear stress transport(SST)k-ωturbulence model,the effect of various vortex generator typ... A relatively high aerodynamic drag is an important factor that hinders the further acceleration of high-speed trains.Using the shear stress transport(SST)k-ωturbulence model,the effect of various vortex generator types on the aerodynamic characteristics of an ICE2(Inter-city Electricity)train has been investigated.The results indi-cate that the vortex generators with wider triangle,trapezoid,and micro-ramp arranged on the surface of the tail car can significantly change the distribution of surface pressure and affect the vorticity intensity in the wake.This alteration effectively reduces the resistance of the tail car.Meanwhile,the micro-ramp vortex generator with its convergent structure at the rear exhibits enhancedflow-guiding capabilities,resulting in a 15.4%reduction in the drag of the tail car. 展开更多
关键词 vortex generator aerodynamic drag REDUCTION numerical simulation
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Detection accuracy of target accelerations based on vortex electromagnetic wave in keyhole space
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作者 郭凯 雷爽 +2 位作者 雷艺 周红平 郭忠义 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期283-290,共8页
The influence of the longitudinal acceleration and the angular acceleration of detecting target based on vortex electromagnetic waves in keyhole space are analyzed.The spectrum spreads of different orbital angular mom... The influence of the longitudinal acceleration and the angular acceleration of detecting target based on vortex electromagnetic waves in keyhole space are analyzed.The spectrum spreads of different orbital angular momentum(OAM)modes in different non-line-of-sight situations are simulated.The errors of target accelerations in detection are calculated and compared based on the OAM spectra spreading by using two combinations of composite OAM modes in the keyhole space.According to the research,the effects about spectrum spreads of higher OAM modes are more obvious.The error in detection is mainly affected by OAM spectrum spreading,which can be reduced by reasonably using different combinations of OAM modes in different practical situations.The above results provide a reference idea for investigating keyhole effect when vortex electromagnetic wave is used to detect accelerations. 展开更多
关键词 vortex electromagnetic waves detect accelerations keyhole space spectrum spread
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Revisit of the anisotropic vortex states of 2H-NbSe_(2) towards the zero-field limit
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作者 张凡 侯兴元 +5 位作者 姜宇轩 张宗源 涂玉兵 朱相德 陈根富 单磊 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期80-86,共7页
We revisited the vortex states of 2H-NbSe_(2) towards zero fields by a low-temperature scanning tunneling microscope.Fine structures of the anisotropic vortex states were distinguished, one is a spatially non-splittin... We revisited the vortex states of 2H-NbSe_(2) towards zero fields by a low-temperature scanning tunneling microscope.Fine structures of the anisotropic vortex states were distinguished, one is a spatially non-splitting zero bias peak, and the other is an in-gap conductance anomaly resembling evolved crossing features around the center of the three nearest vortices.Both of them distribute solely along the next nearest neighboring direction of the vortex lattice and become unresolved in much higher magnetic fields, implying an important role played by the vortex–vortex interactions. To clarify these issues,we have studied the intrinsic vortex states of the isolated trapped vortex in zero fields at 0.45 K. It is concluded that the anisotropic zero bias peak is attributed to the superconducting gap anisotropy, and the spatially evolved crossing features are related to the vortex–vortex interaction. The vortex core size under the zero-field limit is determined. These results provide a paradigm for studying the inherent vortex states of type-II superconductors especially based on an isolated vortex. 展开更多
关键词 vortex states zero-bias conductance peak scanning tunneling microscopy
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Gyrokinetic simulation of magnetic-island-induced electric potential vortex mode
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作者 王丰 李继全 +1 位作者 曲洪鹏 彭晓东 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第1期34-41,共8页
Ion temperature gradient(ITG)-driven turbulence with embedded static magnetic islands is simulated by utilizing a gyrokinetic theory-based global turbulence transport code(GKNET)in this work.Different from the traditi... Ion temperature gradient(ITG)-driven turbulence with embedded static magnetic islands is simulated by utilizing a gyrokinetic theory-based global turbulence transport code(GKNET)in this work.Different from the traditional equilibrium circular magnetic-surface average(EMSA)method,an advanced algorithm that calculates the perturbed magnetic-surface average(PMSA)of the electric potential has been developed to precisely deal with the zonal flow component in a non-circular magnetic surface perturbed by magnetic islands.Simulations show that the electric potential vortex structure inside islands induced by the magnetic islands is usually of odd parity when using the EMSA method.It is found that the odd symmetry vortex can transfer into an even one after a steep zonal flow gradient,i.e.the flow shear has been built in the vicinity of the magnetic islands by adopting the PMSA algorithm.The phase of the potential vortex in the poloidal cross section is coupled with the zonal flow shear.Such an electric potential vortex mode may be of essential importance in wide topics,such as the turbulence spreading across magnetic islands,neoclassical tearing mode physics,and also the interaction dynamics between the micro-turbulence and MHD activities. 展开更多
关键词 magnetic islands electric vortex ITG perturbed magnetic flux surface average
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Tailoring electron vortex beams with customizable intensity patterns by electron diffraction holography
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作者 Pengcheng Huo Ruixuan Yu +3 位作者 Mingze Liu Hui Zhang Yan-qing Lu Ting Xu 《Opto-Electronic Advances》 SCIE EI CAS CSCD 2024年第2期14-21,共8页
An electron vortex beam(EVB) carrying orbital angular momentum(OAM) plays a key role in a series of fundamental scientific researches, such as chiral energy-loss spectroscopy and magnetic dichroism spectroscopy. So fa... An electron vortex beam(EVB) carrying orbital angular momentum(OAM) plays a key role in a series of fundamental scientific researches, such as chiral energy-loss spectroscopy and magnetic dichroism spectroscopy. So far, almost all the experimentally created EVBs manifest isotropic doughnut intensity patterns. Here, based on the correlation between local divergence angle of electron beam and phase gradient along azimuthal direction, we show that free electrons can be tailored to EVBs with customizable intensity patterns independent of the carried OAM. As proof-of-concept, by using computer generated hologram and designing phase masks to shape the incident free electrons in the transmission electron microscope, three structured EVBs carrying identical OAM are tailored to exhibit completely different intensity patterns. Furthermore, through the modal decomposition, we quantitatively investigate their OAM spectral distributions and reveal that structured EVBs present a superposition of a series of different eigenstates induced by the locally varied geometries. These results not only generalize the concept of EVB, but also demonstrate an extra highly controllable degree of freedom for electron beam manipulation in addition to OAM. 展开更多
关键词 electron vortex beam orbital angular momentum diffraction holography
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Diffraction deep neural network-based classification for vector vortex beams
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作者 彭怡翔 陈兵 +1 位作者 王乐 赵生妹 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第3期387-392,共6页
The vector vortex beam(VVB)has attracted significant attention due to its intrinsic diversity of information and has found great applications in both classical and quantum communications.However,a VVB is unavoidably a... The vector vortex beam(VVB)has attracted significant attention due to its intrinsic diversity of information and has found great applications in both classical and quantum communications.However,a VVB is unavoidably affected by atmospheric turbulence(AT)when it propagates through the free-space optical communication environment,which results in detection errors at the receiver.In this paper,we propose a VVB classification scheme to detect VVBs with continuously changing polarization states under AT,where a diffractive deep neural network(DDNN)is designed and trained to classify the intensity distribution of the input distorted VVBs,and the horizontal direction of polarization of the input distorted beam is adopted as the feature for the classification through the DDNN.The numerical simulations and experimental results demonstrate that the proposed scheme has high accuracy in classification tasks.The energy distribution percentage remains above 95%from weak to medium AT,and the classification accuracy can remain above 95%for various strengths of turbulence.It has a faster convergence and better accuracy than that based on a convolutional neural network. 展开更多
关键词 vector vortex beam diffractive deep neural network classification atmospheric turbulence
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Terahertz quasi-perfect vortex beam with integer-order and fractional-order generated by spiral spherical harmonic axicon
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作者 涂思语 刘德峰 +2 位作者 刘劲松 杨振刚 王可嘉 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期458-467,共10页
We propose a new method to generate terahertz perfect vortex beam with integer-order and fractional-order. A new optical diffractive element composed of the phase combination of a spherical harmonic axicon and a spira... We propose a new method to generate terahertz perfect vortex beam with integer-order and fractional-order. A new optical diffractive element composed of the phase combination of a spherical harmonic axicon and a spiral phase plate is designed and called spiral spherical harmonic axicon. A terahertz Gaussian beam passes through the spiral spherical harmonic axicon to generate a terahertz vortex beam. When only the topological charge number carried by spiral spherical harmonic axicon increases, the ring radius of terahertz vortex beam increases slightly, so the beam is shaped into a terahertz quasi-perfect vortex beam. Importantly, the terahertz quasi-perfect vortex beam can carry not only integer-order topological charge number but also fractional-order topological charge number. This is the first time that vortex beam and quasi-perfect vortex beam with fractional-order have been successfully realized in terahertz domain and experiment. 展开更多
关键词 TERAHERTZ spiral spherical harmonic axicon quasi-perfect vortex beam topological charge number
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Spatial quantum coherent modulation with perfect hybrid vector vortex beam based on atomic medium
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作者 马燕 杨欣 +6 位作者 常虹 杨鑫琪 曹明涛 张晓斐 高宏 董瑞芳 张首刚 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期360-364,共5页
The perfect hybrid vector vortex beam(PHVVB)with helical phase wavefront structure has aroused significant concern in recent years,as its beam waist does not expand with the topological charge(TC).In this work,we inve... The perfect hybrid vector vortex beam(PHVVB)with helical phase wavefront structure has aroused significant concern in recent years,as its beam waist does not expand with the topological charge(TC).In this work,we investigate the spatial quantum coherent modulation effect with PHVVB based on the atomic medium,and we observe the absorption characteristic of the PHVVB with different TCs under variant magnetic fields.We find that the transmission spectrum linewidth of PHVVB can be effectively maintained regardless of the TC.Still,the width of transmission peaks increases slightly as the beam size expands in hot atomic vapor.This distinctive quantum coherence phenomenon,demonstrated by the interaction of an atomic medium with a hybrid vector-structured beam,might be anticipated to open up new opportunities for quantum coherence modulation and accurate magnetic field measurement. 展开更多
关键词 perfect hybrid vector vortex beam topological charge quantum coherence optical manipulation
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Unraveling the Quantum Web: The Vortex Theory of Mass and Matter Formation
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作者 Nader Butto 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第3期1195-1225,共31页
Mass plays a role in many physical phenomena, including the behavior of subatomic particles, the formation and behavior of stars and galaxies, and gravitational interactions between objects. The density of vacuum, 9.5... Mass plays a role in many physical phenomena, including the behavior of subatomic particles, the formation and behavior of stars and galaxies, and gravitational interactions between objects. The density of vacuum, 9.5 × 10−27 kg/m3, is a crucial parameter in the theory of cosmic inflation and is responsible for the accelerated expansion of the universe in its early stages. This vacuum energy interacts with matter and manifests itself as mass, which can be described as flow and vortex formation using the laws of hydrodynamics. The vortex model of elementary particles, in conjunction with the laws of hydrodynamics, provides an elegant explanation for the origin of mass and the relationship between mass and energy, with profound implications for the behavior of objects at high velocities and strong gravitational fields. The vacuum behaves as a compressible superfluid, thus elementary particles can be described as vortices of the vacuum. The equations of hydrodynamics for vortices can be applied to describe the nature and value of the mass of particles. The implications of understanding the nature of mass are vast and profound. From elucidating the fundamental properties of particles to informing the design of advanced materials and technologies, this knowledge is indispensable. It drives advancements across numerous fields, transforming both our theoretical understanding and practical capabilities. Continued research into the nature of mass promises to unlock further insights, fostering innovation and expanding the frontiers of science and technology. 展开更多
关键词 Dark Energy Dark Matter Vacuum MASS Subatomic Particles Cosmic Inflation Virtual Particles vortex Formation HYDRODYNAMICS Density
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Optimization of extreme ultraviolet vortex beam based on high harmonic generation
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作者 肖礴 赵逸文 +6 位作者 程方晶 王革文 姜威 王一琛 胡杰 梁红静 马日 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期459-464,共6页
In high harmonic generation(HHG),Laguerre–Gaussian(LG) beams are used to generate extreme ultraviolet(XUV)vortices with well-defined orbital angular momentum(OAM),which have potential applications in fields such as m... In high harmonic generation(HHG),Laguerre–Gaussian(LG) beams are used to generate extreme ultraviolet(XUV)vortices with well-defined orbital angular momentum(OAM),which have potential applications in fields such as microscopy and spectroscopy.An experimental study on the HHG driven by vortex and Gaussian beams is conducted in this work.It is found that the intensity of vortex harmonics is positively correlated with the laser energy and gas pressure.The structure and intensity distribution of the vortex harmonics exhibit significant dependence on the relative position between the gas jet and the laser focus.The ring-like structures observed in the vortex harmonics,and the interference of quantum paths provide an explanation for the distinct structural characteristics.Moreover,by adjusting the relative position between the jet and laser focus,it is possible to discern the contributions from different quantum paths.The optimization of the HH vortex field is applicable to the XUV,which opens up a new way for exploiting the potential in optical spin or manipulating electrons by using the photon with tunable orbital angular momentum. 展开更多
关键词 high harmonic generation phase matching extreme ultraviolet vortex beam quantum path interference
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Mechanism of Diabatic Heating on Precipitation and the Track of a Tibetan Plateau Vortex over the Eastern Slope of the Tibetan Plateau
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作者 Yuanchang DONG Guoping LI +3 位作者 Xiaolin XIE Long YANG Peiwen ZHANG Bo ZENG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第1期155-172,共18页
Existing studies contend that latent heating(LH)will replace sensible heating(SH)to become the dominant factor affecting the development of the Tibetan Plateau vortex(TPV)after it moves off the Tibetan Plateau(TP).How... Existing studies contend that latent heating(LH)will replace sensible heating(SH)to become the dominant factor affecting the development of the Tibetan Plateau vortex(TPV)after it moves off the Tibetan Plateau(TP).However,in the process of the TPV moving off the TP requires that the airmass traverse the eastern slope of the Tibetan Plateau(ESTP)where the topography and diabatic heating(DH)conditions rapidly change.How LH gradually replaces SH to become the dominant factor in the development of the TPV over the ESTP is still not very clear.In this paper,an analysis of a typical case of a TPV with a long life history over the ESTP is performed by using multi-sourced meteorological data and model simulations.The results show that SH from the TP surface can change the TPV-associated precipitation distribution by temperature advection after the TPV moves off the TP.The LH can then directly promote the development of the TPV and has a certain guiding effect on the track of the TPV.The SH can control the active area of LH by changing the falling area of the TPV-associated precipitation,so it still plays a key role in the development and tracking of the TPV even though it has moved out of the main body of the TP. 展开更多
关键词 eastern slope of the Tibetan Plateau diabatic heating Tibetan Plateau vortex precipitation distribution TRACK
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Kármán vortex street in a spin–orbit-coupled Bose–Einstein condensate with PT symmetry
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作者 邵凯花 席保龙 +5 位作者 席忠红 涂朴 王青青 马金萍 赵茜 石玉仁 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期289-296,共8页
The dynamics of spin–orbit-coupled Bose–Einstein condensate with parity-time symmetry through a moving obstacle potential is simulated numerically. In the miscible two-component condensate, the formation of the K... The dynamics of spin–orbit-coupled Bose–Einstein condensate with parity-time symmetry through a moving obstacle potential is simulated numerically. In the miscible two-component condensate, the formation of the Kármán vortex street is observed in one component, while ‘the half-quantum vortex street' is observed in the other component. Other patterns of vortex shedding, such as oblique vortex dipoles, V-shaped vortex pairs, irregular turbulence, and combined modes of various wakes, can also be found. The ratio of inter-vortex spacing in one row to the distance between vortex rows is approximately0.18, which is less than the stability condition 0.28 of classical fluid. The drag force acting on the obstacle potential is simulated. The parametric regions of Kármán vortex street and other vortex patterns are calculated. The range of Kármán vortex street is surrounded by the region of combined modes. In addition, spin–orbit coupling disrupts the symmetry of the system and the gain-loss affects the local particle distribution of the system, which leads to the local symmetry breaking of the system, and finally influences the stability of the Kármán vortex street. Finally, we propose an experimental protocol to realize the Kármán vortex street in a system. 展开更多
关键词 Kármán vortex street Bose–Einstein condensate spin–orbit-coupled parity-time symmetry
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Adding vortexing to the Maki technique provides no benefit for the diagnosis of catheter colonization or catheter-related bacteremia
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作者 Leonardo Lorente Maria Lecuona Fernandez +7 位作者 Adriana González-Mesa Judith Oliveras-Roura Cristina Rosado Pablo Cabrera Emma Casal Alejandro Jiménez María Luisa Mora Ana Madueño 《World Journal of Critical Care Medicine》 2024年第1期58-64,共7页
BACKGROUND A previous study compared vortexing and Maki techniques for the diagnosis of catheter-related bloodstream infection(CRBSI),and concluded that vortexing was not superior to Maki method.AIM To determine wheth... BACKGROUND A previous study compared vortexing and Maki techniques for the diagnosis of catheter-related bloodstream infection(CRBSI),and concluded that vortexing was not superior to Maki method.AIM To determine whether the combined use of vortexing and Maki techniques provides profitability versus the Maki technique for the diagnosis of catheter tip colonization(CTC)and CRBSI.METHODS Observational and prospective study carried out in an Intensive Care Unit.Patients with suspected catheter-related infection(CRI)and with one central venous catheter for at least 7 days were included.The area under the curve(AUC)of the Maki technique,the vortexing technique and the combination of both techniques for the diagnosis of CTC and CRBSI were compared.RESULTS We included 136 episodes of suspected CRI.We found 21 cases of CTC of which 10 were also CRBSI cases.Of the 21 CTC episodes,18(85.7%)were diagnosed by Maki technique and vortexing technique,3(14.3%)only by the technique of Maki,and none only by technique of vortexing.Of the 10 CRBSI episodes,9(90.0%)were diagnosed by the techniques of Maki and vortexing,1(10.0%)was diagnosed only by the technique of Maki,and none only by the technique of vortexing.We no found differences in the comparison of AUC between the technique of Maki and the combination of Maki and vortexing techniques for the diagnosis of CTC(P=0.99)and CRBSI(P=0.99).CONCLUSION The novel finding of our study was that the combined use of vortexing and Maki techniques did not provide profitability to the technique of Maki alone to CRBSI diagnosis of. 展开更多
关键词 vortexing Maki Bloodstream infection COLONIZATION
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Improving millimeter-wave imaging quality using the vortex phase method
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作者 Nairui Hu Feng Qi +3 位作者 Yelong Wang Zhaoyang Liu Pengxiang Liu Weifan Li 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第9期193-202,共10页
This paper investigates a new vortex wave imaging approach to improve the imaging quality of small metal targets of size less than 1.5 mm.Antennas with different spiral phase plates are designed to efficiently transmi... This paper investigates a new vortex wave imaging approach to improve the imaging quality of small metal targets of size less than 1.5 mm.Antennas with different spiral phase plates are designed to efficiently transmit vortex beams with orbital angular momentums(OAMs).By analyzing the OAM spectrum of the target,it was discovered that the predominant reflection contains a particular OAM mode that carries abundant azimuthal information.This can be explained by the OAM selectivity of the target and the guidance of the vortex transmitting beam.A simple reflection vortex imaging system was designed to capture the phase information.Measurement results show that the high image contrast reaches 14.9%,which is twice as high as that of the imaging without OAM.Both of simulations and experiments demonstrate that the vortex phase imaging approach proposed in this paper can effectively improve the imaging quality at 80 GHz.This approach is suitable for other millimeter wave imaging systems and is helpful to improve the resolution in anti-terrorism security checks. 展开更多
关键词 Orbital angular momentums(OAMs)beams Focal plane imaging Spiral phase plates(SPPs) vortex spectrum
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