BACKGROUND Insomnia is a disease where individuals cannot maintain a steady and stable sleep state or fail to fall asleep.Western medicine mainly uses sedatives and hypnotic drugs to treat insomnia,and long-term use i...BACKGROUND Insomnia is a disease where individuals cannot maintain a steady and stable sleep state or fail to fall asleep.Western medicine mainly uses sedatives and hypnotic drugs to treat insomnia,and long-term use is prone to drug resistance and other adverse reactions.Acupuncture has a good curative effect and unique advantages in the treatment of insomnia.AIM To explore the molecular mechanism of acupuncture at Back-Shu point for the treatment of insomnia.METHODS We first prepared a rat model of insomnia,and then carried out acupuncture for 7 consecutive days.After treatment,the sleep time and general behavior of the rats were determined.The Morris water maze test was used to assess the learning ability and spatial memory ability of the rats.The expression levels of inflammatory cytokines in serum and the hippocampus were detected by ELISA.qRTPCR was used to detect the mRNA expression changes in the ERK/NF-κB signaling pathway.Western blot and immunohistochemistry were carried out to evaluate the protein expression levels of RAF-1,MEK-2,ERK1/2 and NF-κB.RESULTS Acupuncture can prolong sleep duration,and improve mental state,activity,diet volume,learning ability and spatial memory.In addition,acupuncture increased the release of 1L-1β,1L-6 and TNF-αin serum and the hippocampus and inhibited the mRNA and protein expression of the ERK/NF-κB signaling pathway.CONCLUSION These findings suggest that acupuncture at Back-Shu point can inhibit the ERK/NF-κB signaling pathway and treat insomnia by increasing the release of inflammatory cytokines in the hippocampus.展开更多
Objective:To observe the effect of intradermal needle therapy on back-shu points of five zang organs in treating chronic fatigue syndrome(CFS)and provide evidence for the usage of unilateral back-shu point.Methods:Pat...Objective:To observe the effect of intradermal needle therapy on back-shu points of five zang organs in treating chronic fatigue syndrome(CFS)and provide evidence for the usage of unilateral back-shu point.Methods:Patients were randomly divided into bilateral back-shu point group,unilateral back-shu point group and non-acupoint group,remove shedding cases,each group remaining 30 patients.In bilateral back-shu point group,both sides of back-shu points of five zang organs were selected.In unilateral back-shu point group,only one side was selected,left or right alternately.The location where non-acupoint group inserted by intradermal needles were outward from the back-shu points,left or right alternately.Fatigue Scale-14(FS-14)was used to evaluate the fatigue level and the scores’improvement of physical fatigue and mental fatigue revealed the therapeutic effect on body constituents and spirits of CFS patient.Results:After the 8-week intradermal needle therapy,the total effective rate was 83.33%in the bilateral back-shu point group,which was 76.67%in the unilateral back-shu point group and 50.00%in the non-acupoint group.The curative effects of the two groups whose back-shu points of five zang organs were inserted by intradermal needles were better than the non-acupoint group(P<0.05).There was no significant difference in clinical efficacy between the bilateral back-shu point group and the unilateral back-shu point group(P>0.05).There were statistical differences in FS-14 questionnaires including total,physical and mental scores between before and after the treatment in both the two back-shu point groups(P<0.05).Only the scores of total and physical fatigue in decreased in non-acupoint group(P<0.05),which means it couldn’t help to alleviate mental fatigue statistically(P>0.05).Conclusions:(1)The intradermal needle therapy on back-shu points of five zang organs for CFS has a satisfying clinical efficacy in curing tiredness.It can help to reduce both physical and mental fatigue for the patients.Hence,it can regulate both body constituents and spirits simultaneously.(2)Needling the unilateral acupoints can get similar clinical efficacy to the bilateral points.It reveals that we can cut cost by reducing the consumption of the amount of intradermal needles used on one side.(3)Both the groups of back-shu points get better clinical efficacy than the non-acupoint group dramatically.The reason of why the intradermal needle can treat CFS maybe that back-shu points of five zang organs can regulate the functions of five zang organs characteristically.展开更多
To observe the clinical effect of treatment of acute bronchitis primarily with prickingcupping method on Back-shu points. Methods. The patients of acute bronchitis were randomly divided into 2 groups. In the observati...To observe the clinical effect of treatment of acute bronchitis primarily with prickingcupping method on Back-shu points. Methods. The patients of acute bronchitis were randomly divided into 2 groups. In the observation group, there were 36 cases, who were treated with the integrated traditional Chinese and western medicine, primarily the pricking-cupping method on Back-shu points; while in the control group, there were 29 cases who were given the conventinal treatment of western medicine. All the 2 groups were treated for 7 days as one treating course. Results: The total effective rate of the observation group was 97.2% while that of the control group was 82,8%, so there is a significant difference between them. On the first and third days the clinical manifestations were more satisfactorily improved in the treatment group than in the control group (P 〈 0.01) and on the fifth and seventh days, the comparison showed no significant difference (P〉0.05). Conclusion: The treatment of acute bronchitis by means of the integrated traditional Chinese and western medicine primarily with pricking-cupping method on Back-shu points is of marked therapeutic effect, simple manipulation, and little untoward effects, thus claiming the unique advantage.展开更多
Urticaria is a common and frequently encountered disease, which is mainly manifested by extreme pruritus and lumpish eruption of the skin. Acute urticaria with a short disease course can be cured, while the chronic on...Urticaria is a common and frequently encountered disease, which is mainly manifested by extreme pruritus and lumpish eruption of the skin. Acute urticaria with a short disease course can be cured, while the chronic one with repeated attacks is a lingering disorder. In the past few years, 40 cases of urticaria were treated by cupping at the back-shu points of the five zang-organs and Geshu (BL 17). Another 20 cases in the control group were treated with Fang Feng Tong Sheng Wan (防风通圣丸Miraculous Pills of Ledebouriella) and chlorpheniramine maleate. The therapeutic effect in the treatment group was significantly superior to that in the control group. The results are reported as follows.展开更多
Objective To observe the clinical therapeutic effect on insomnia treated with acupuncture at back-shu points. Methods Sixty-four cases of insomnia were selected and divided randomly into a back-shu points group (grou...Objective To observe the clinical therapeutic effect on insomnia treated with acupuncture at back-shu points. Methods Sixty-four cases of insomnia were selected and divided randomly into a back-shu points group (group A) and a conventional acupoints group (group B) by a computer generated allocation list, 32 cases in each one. In the trial group, acupuncture was applied at xinshu (心俞 15), Ganshu (刊俞 18), Pishu (脾俞 BL 20) and Geshu (膈俞 BL 17). In the control group, acupuncture was applied conventionally to Neiguan (内关 PC 6), Shenmen (神门 HT 7), Sanyinjiao (三阴交 SP 6), Baihui (百会 GV 20) and Sishencong (四神聪 EX-HN 2). Ten treatments made a session. The efficacy was analyzed statistically after 3 sessions of treatment. Results There were significant differences between the two groups in the relief of sleep disorders after the treatment (P〈0.O2). The improvement in sleep efficiency was different significantly (P〈0.05). The difference in sleep difficulty was significant in Chinese medicine (TCM) symptom score (P〈0.05). Conclusion The clinical efficacy is achieved by either acupuncture at back-shu points or by acupuncture at conventional acupoints. The improvements of sleep efficiency and sleep disorder scores in PSO.I, and sleep difficulty in TCM as well as the long-term efficacy are superior in group A as compared with those in group B.展开更多
Recently, there have been some attempts of Transformer in 3D point cloud classification. In order to reduce computations, most existing methods focus on local spatial attention,but ignore their content and fail to est...Recently, there have been some attempts of Transformer in 3D point cloud classification. In order to reduce computations, most existing methods focus on local spatial attention,but ignore their content and fail to establish relationships between distant but relevant points. To overcome the limitation of local spatial attention, we propose a point content-based Transformer architecture, called PointConT for short. It exploits the locality of points in the feature space(content-based), which clusters the sampled points with similar features into the same class and computes the self-attention within each class, thus enabling an effective trade-off between capturing long-range dependencies and computational complexity. We further introduce an inception feature aggregator for point cloud classification, which uses parallel structures to aggregate high-frequency and low-frequency information in each branch separately. Extensive experiments show that our PointConT model achieves a remarkable performance on point cloud shape classification. Especially, our method exhibits 90.3% Top-1 accuracy on the hardest setting of ScanObjectN N. Source code of this paper is available at https://github.com/yahuiliu99/PointC onT.展开更多
The material point method(MPM)has been gaining increasing popularity as an appropriate approach to the solution of coupled hydro-mechanical problems involving large deformation.In this paper,we survey the current stat...The material point method(MPM)has been gaining increasing popularity as an appropriate approach to the solution of coupled hydro-mechanical problems involving large deformation.In this paper,we survey the current state-of-the-art in the MPM simulation of hydro-mechanical behaviour in two-phase porous geomaterials.The review covers the recent advances and developments in the MPM and their extensions to capture the coupled hydro-mechanical problems involving large deformations.The focus of this review is aiming at providing a clear picture of what has or has not been developed or implemented for simulating two-phase coupled large deformation problems,which will provide some direct reference for both practitioners and researchers.展开更多
Identification of the ice channel is the basic technology for developing intelligent ships in ice-covered waters,which is important to ensure the safety and economy of navigation.In the Arctic,merchant ships with low ...Identification of the ice channel is the basic technology for developing intelligent ships in ice-covered waters,which is important to ensure the safety and economy of navigation.In the Arctic,merchant ships with low ice class often navigate in channels opened up by icebreakers.Navigation in the ice channel often depends on good maneuverability skills and abundant experience from the captain to a large extent.The ship may get stuck if steered into ice fields off the channel.Under this circumstance,it is very important to study how to identify the boundary lines of ice channels with a reliable method.In this paper,a two-staged ice channel identification method is developed based on image segmentation and corner point regression.The first stage employs the image segmentation method to extract channel regions.In the second stage,an intelligent corner regression network is proposed to extract the channel boundary lines from the channel region.A non-intelligent angle-based filtering and clustering method is proposed and compared with corner point regression network.The training and evaluation of the segmentation method and corner regression network are carried out on the synthetic and real ice channel dataset.The evaluation results show that the accuracy of the method using the corner point regression network in the second stage is achieved as high as 73.33%on the synthetic ice channel dataset and 70.66%on the real ice channel dataset,and the processing speed can reach up to 14.58frames per second.展开更多
Cultural relics line graphic serves as a crucial form of traditional artifact information documentation,which is a simple and intuitive product with low cost of displaying compared with 3D models.Dimensionality reduct...Cultural relics line graphic serves as a crucial form of traditional artifact information documentation,which is a simple and intuitive product with low cost of displaying compared with 3D models.Dimensionality reduction is undoubtedly necessary for line drawings.However,most existing methods for artifact drawing rely on the principles of orthographic projection that always cannot avoid angle occlusion and data overlapping while the surface of cultural relics is complex.Therefore,conformal mapping was introduced as a dimensionality reduction way to compensate for the limitation of orthographic projection.Based on the given criteria for assessing surface complexity,this paper proposed a three-dimensional feature guideline extraction method for complex cultural relic surfaces.A 2D and 3D combined factor that measured the importance of points on describing surface features,vertex weight,was designed.Then the selection threshold for feature guideline extraction was determined based on the differences between vertex weight and shape index distributions.The feasibility and stability were verified through experiments conducted on real cultural relic surface data.Results demonstrated the ability of the method to address the challenges associated with the automatic generation of line drawings for complex surfaces.The extraction method and the obtained results will be useful for line graphic drawing,displaying and propaganda of cultural relics.展开更多
输电线路的关键部位包括塔身、导线、绝缘子、避雷线以及引流线,无人机精细化导航的首要任务是构造输电线路的点云地图并从中分割出上述部位。为解决现有算法在输电线路的绝缘子、引流线等精细结构分割时精度低的问题,通过改进PointNet+...输电线路的关键部位包括塔身、导线、绝缘子、避雷线以及引流线,无人机精细化导航的首要任务是构造输电线路的点云地图并从中分割出上述部位。为解决现有算法在输电线路的绝缘子、引流线等精细结构分割时精度低的问题,通过改进PointNet++算法,提出了一种面向输电线路精细结构的点云分割方法。首先,基于无人机机载激光雷达在现场采集的点云数据,构造了输电线路点云分割数据集;其次,通过对比实验,筛选出在本输电线路场景下合理的数据增强方法,并对数据集进行了数据增强;最后,将自注意力机制以及倒置残差结构和PointNet++相结合,设计了输电线路关键部位点云语义分割算法。实验结果表明:该改进PointNet++算法在全场景输电线路现场点云数据作为输入的前提下,首次实现了对引流线、绝缘子等输电线路中精细结构和导线、杆塔塔身以及输电线路无关背景点的同时分割,平均交并比(mean intersection over union,mIoU)达80.79%,所有类别分割的平均F_(1)值(F1 score)达88.99%。展开更多
Using angle-resolved photoemission spectroscopy and density functional theory calculations methods,we investigate the electronic structures and topological properties of ternary tellurides NbIrTe_(4),a candidate for t...Using angle-resolved photoemission spectroscopy and density functional theory calculations methods,we investigate the electronic structures and topological properties of ternary tellurides NbIrTe_(4),a candidate for type-II Weyl semimetal.We demonstrate the presence of several Fermi arcs connecting their corresponding Weyl points on both termination surfaces of the topological material.Our analysis reveals the existence of Dirac points,in addition to Weyl points,giving both theoretical and experimental evidences of the coexistence of Dirac and Weyl points in a single material.These findings not only confirm NbIrTe_(4) as a unique topological semimetal but also open avenues for exploring novel electronic devices based on its coexisting Dirac and Weyl fermions.展开更多
Internet Exchange Point(IXP)is a system that increases network bandwidth performance.Internet exchange points facilitate interconnection among network providers,including Internet Service Providers(ISPs)andContent Del...Internet Exchange Point(IXP)is a system that increases network bandwidth performance.Internet exchange points facilitate interconnection among network providers,including Internet Service Providers(ISPs)andContent Delivery Providers(CDNs).To improve service management,Internet exchange point providers have adopted the Software Defined Network(SDN)paradigm.This implementation is known as a Software-Defined Exchange Point(SDX).It improves network providers’operations and management.However,performance issues still exist,particularly with multi-hop topologies.These issues include switch memory costs,packet processing latency,and link failure recovery delays.The paper proposes Enhanced Link Failure Rerouting(ELFR),an improved mechanism for rerouting link failures in software-defined exchange point networks.The proposed mechanism aims to minimize packet processing time for fast link failure recovery and enhance path calculation efficiency while reducing switch storage overhead by exploiting the Programming Protocol-independent Packet Processors(P4)features.The paper presents the proposed mechanisms’efficiency by utilizing advanced algorithms and demonstrating improved performance in packet processing speed,path calculation effectiveness,and switch storage management compared to current mechanisms.The proposed mechanism shows significant improvements,leading to a 37.5%decrease in Recovery Time(RT)and a 33.33%decrease in both Calculation Time(CT)and Computational Overhead(CO)when compared to current mechanisms.The study highlights the effectiveness and resource efficiency of the proposed mechanism in effectively resolving crucial issues inmulti-hop software-defined exchange point networks.展开更多
We present an application of short-pulse laser-generated hard x rays for the diagnosis of indirectly driven double shell targets. Coneinserted double shell targets were imploded through an indirect drive approach on t...We present an application of short-pulse laser-generated hard x rays for the diagnosis of indirectly driven double shell targets. Coneinserted double shell targets were imploded through an indirect drive approach on the upgraded SG-II laser facility. Then, based on thepoint-projection hard x-ray radiography technique, time-resolved radiography of the double shell targets, including that of their near-peakcompression, were obtained. The backlighter source was created by the interactions of a high-intensity short pulsed laser with a metalmicrowire target. Images of the target near peak compression were obtained with an Au microwire. In addition, radiation hydrodynamicsimulations were performed, and the target evolution obtained agrees well with the experimental results. Using the radiographic images, arealdensities of the targets were evaluated.展开更多
We study the exceptional-point(EP) structure and the associated quantum dynamics in a system consisting of a non-Hermitian qubit and a Hermitian qubit. We find that the system possesses two sets of EPs, which divide t...We study the exceptional-point(EP) structure and the associated quantum dynamics in a system consisting of a non-Hermitian qubit and a Hermitian qubit. We find that the system possesses two sets of EPs, which divide the systemparameter space into PT-symmetry unbroken, partially broken and fully broken regimes, each with distinct quantumdynamics characteristics. Particularly, in the partially broken regime, while the PT-symmetry is generally broken in the whole four-dimensional Hilbert space, it is preserved in a two-dimensional subspace such that the quantum dynamics in the subspace are similar to those in the PT-symmetry unbroken regime. In addition, we reveal that the competition between the inter-qubit coupling and the intra-qubit driving gives rise to a complex pattern in the EP variation with system parameters.展开更多
文摘BACKGROUND Insomnia is a disease where individuals cannot maintain a steady and stable sleep state or fail to fall asleep.Western medicine mainly uses sedatives and hypnotic drugs to treat insomnia,and long-term use is prone to drug resistance and other adverse reactions.Acupuncture has a good curative effect and unique advantages in the treatment of insomnia.AIM To explore the molecular mechanism of acupuncture at Back-Shu point for the treatment of insomnia.METHODS We first prepared a rat model of insomnia,and then carried out acupuncture for 7 consecutive days.After treatment,the sleep time and general behavior of the rats were determined.The Morris water maze test was used to assess the learning ability and spatial memory ability of the rats.The expression levels of inflammatory cytokines in serum and the hippocampus were detected by ELISA.qRTPCR was used to detect the mRNA expression changes in the ERK/NF-κB signaling pathway.Western blot and immunohistochemistry were carried out to evaluate the protein expression levels of RAF-1,MEK-2,ERK1/2 and NF-κB.RESULTS Acupuncture can prolong sleep duration,and improve mental state,activity,diet volume,learning ability and spatial memory.In addition,acupuncture increased the release of 1L-1β,1L-6 and TNF-αin serum and the hippocampus and inhibited the mRNA and protein expression of the ERK/NF-κB signaling pathway.CONCLUSION These findings suggest that acupuncture at Back-Shu point can inhibit the ERK/NF-κB signaling pathway and treat insomnia by increasing the release of inflammatory cytokines in the hippocampus.
基金Xin'ao Award Funded Project of Beijing University of Chinese Medicine(No.2018-XAJLJJ-015)。
文摘Objective:To observe the effect of intradermal needle therapy on back-shu points of five zang organs in treating chronic fatigue syndrome(CFS)and provide evidence for the usage of unilateral back-shu point.Methods:Patients were randomly divided into bilateral back-shu point group,unilateral back-shu point group and non-acupoint group,remove shedding cases,each group remaining 30 patients.In bilateral back-shu point group,both sides of back-shu points of five zang organs were selected.In unilateral back-shu point group,only one side was selected,left or right alternately.The location where non-acupoint group inserted by intradermal needles were outward from the back-shu points,left or right alternately.Fatigue Scale-14(FS-14)was used to evaluate the fatigue level and the scores’improvement of physical fatigue and mental fatigue revealed the therapeutic effect on body constituents and spirits of CFS patient.Results:After the 8-week intradermal needle therapy,the total effective rate was 83.33%in the bilateral back-shu point group,which was 76.67%in the unilateral back-shu point group and 50.00%in the non-acupoint group.The curative effects of the two groups whose back-shu points of five zang organs were inserted by intradermal needles were better than the non-acupoint group(P<0.05).There was no significant difference in clinical efficacy between the bilateral back-shu point group and the unilateral back-shu point group(P>0.05).There were statistical differences in FS-14 questionnaires including total,physical and mental scores between before and after the treatment in both the two back-shu point groups(P<0.05).Only the scores of total and physical fatigue in decreased in non-acupoint group(P<0.05),which means it couldn’t help to alleviate mental fatigue statistically(P>0.05).Conclusions:(1)The intradermal needle therapy on back-shu points of five zang organs for CFS has a satisfying clinical efficacy in curing tiredness.It can help to reduce both physical and mental fatigue for the patients.Hence,it can regulate both body constituents and spirits simultaneously.(2)Needling the unilateral acupoints can get similar clinical efficacy to the bilateral points.It reveals that we can cut cost by reducing the consumption of the amount of intradermal needles used on one side.(3)Both the groups of back-shu points get better clinical efficacy than the non-acupoint group dramatically.The reason of why the intradermal needle can treat CFS maybe that back-shu points of five zang organs can regulate the functions of five zang organs characteristically.
文摘To observe the clinical effect of treatment of acute bronchitis primarily with prickingcupping method on Back-shu points. Methods. The patients of acute bronchitis were randomly divided into 2 groups. In the observation group, there were 36 cases, who were treated with the integrated traditional Chinese and western medicine, primarily the pricking-cupping method on Back-shu points; while in the control group, there were 29 cases who were given the conventinal treatment of western medicine. All the 2 groups were treated for 7 days as one treating course. Results: The total effective rate of the observation group was 97.2% while that of the control group was 82,8%, so there is a significant difference between them. On the first and third days the clinical manifestations were more satisfactorily improved in the treatment group than in the control group (P 〈 0.01) and on the fifth and seventh days, the comparison showed no significant difference (P〉0.05). Conclusion: The treatment of acute bronchitis by means of the integrated traditional Chinese and western medicine primarily with pricking-cupping method on Back-shu points is of marked therapeutic effect, simple manipulation, and little untoward effects, thus claiming the unique advantage.
文摘Urticaria is a common and frequently encountered disease, which is mainly manifested by extreme pruritus and lumpish eruption of the skin. Acute urticaria with a short disease course can be cured, while the chronic one with repeated attacks is a lingering disorder. In the past few years, 40 cases of urticaria were treated by cupping at the back-shu points of the five zang-organs and Geshu (BL 17). Another 20 cases in the control group were treated with Fang Feng Tong Sheng Wan (防风通圣丸Miraculous Pills of Ledebouriella) and chlorpheniramine maleate. The therapeutic effect in the treatment group was significantly superior to that in the control group. The results are reported as follows.
基金Supported by National Natural Science Foundation:No.81173335
文摘Objective To observe the clinical therapeutic effect on insomnia treated with acupuncture at back-shu points. Methods Sixty-four cases of insomnia were selected and divided randomly into a back-shu points group (group A) and a conventional acupoints group (group B) by a computer generated allocation list, 32 cases in each one. In the trial group, acupuncture was applied at xinshu (心俞 15), Ganshu (刊俞 18), Pishu (脾俞 BL 20) and Geshu (膈俞 BL 17). In the control group, acupuncture was applied conventionally to Neiguan (内关 PC 6), Shenmen (神门 HT 7), Sanyinjiao (三阴交 SP 6), Baihui (百会 GV 20) and Sishencong (四神聪 EX-HN 2). Ten treatments made a session. The efficacy was analyzed statistically after 3 sessions of treatment. Results There were significant differences between the two groups in the relief of sleep disorders after the treatment (P〈0.O2). The improvement in sleep efficiency was different significantly (P〈0.05). The difference in sleep difficulty was significant in Chinese medicine (TCM) symptom score (P〈0.05). Conclusion The clinical efficacy is achieved by either acupuncture at back-shu points or by acupuncture at conventional acupoints. The improvements of sleep efficiency and sleep disorder scores in PSO.I, and sleep difficulty in TCM as well as the long-term efficacy are superior in group A as compared with those in group B.
基金supported in part by the Nationa Natural Science Foundation of China (61876011)the National Key Research and Development Program of China (2022YFB4703700)+1 种基金the Key Research and Development Program 2020 of Guangzhou (202007050002)the Key-Area Research and Development Program of Guangdong Province (2020B090921003)。
文摘Recently, there have been some attempts of Transformer in 3D point cloud classification. In order to reduce computations, most existing methods focus on local spatial attention,but ignore their content and fail to establish relationships between distant but relevant points. To overcome the limitation of local spatial attention, we propose a point content-based Transformer architecture, called PointConT for short. It exploits the locality of points in the feature space(content-based), which clusters the sampled points with similar features into the same class and computes the self-attention within each class, thus enabling an effective trade-off between capturing long-range dependencies and computational complexity. We further introduce an inception feature aggregator for point cloud classification, which uses parallel structures to aggregate high-frequency and low-frequency information in each branch separately. Extensive experiments show that our PointConT model achieves a remarkable performance on point cloud shape classification. Especially, our method exhibits 90.3% Top-1 accuracy on the hardest setting of ScanObjectN N. Source code of this paper is available at https://github.com/yahuiliu99/PointC onT.
基金The financial supports from National Outstanding Youth Science Fund Project of National Natural Science Foundation of China(Grant No.52022112)the International Postdoctoral Exchange Fellowship Program(Talent-Introduction Program,Grant No.YJ20220219)。
文摘The material point method(MPM)has been gaining increasing popularity as an appropriate approach to the solution of coupled hydro-mechanical problems involving large deformation.In this paper,we survey the current state-of-the-art in the MPM simulation of hydro-mechanical behaviour in two-phase porous geomaterials.The review covers the recent advances and developments in the MPM and their extensions to capture the coupled hydro-mechanical problems involving large deformations.The focus of this review is aiming at providing a clear picture of what has or has not been developed or implemented for simulating two-phase coupled large deformation problems,which will provide some direct reference for both practitioners and researchers.
基金financially supported by the National Key Research and Development Program(Grant No.2022YFE0107000)the General Projects of the National Natural Science Foundation of China(Grant No.52171259)the High-Tech Ship Research Project of the Ministry of Industry and Information Technology(Grant No.[2021]342)。
文摘Identification of the ice channel is the basic technology for developing intelligent ships in ice-covered waters,which is important to ensure the safety and economy of navigation.In the Arctic,merchant ships with low ice class often navigate in channels opened up by icebreakers.Navigation in the ice channel often depends on good maneuverability skills and abundant experience from the captain to a large extent.The ship may get stuck if steered into ice fields off the channel.Under this circumstance,it is very important to study how to identify the boundary lines of ice channels with a reliable method.In this paper,a two-staged ice channel identification method is developed based on image segmentation and corner point regression.The first stage employs the image segmentation method to extract channel regions.In the second stage,an intelligent corner regression network is proposed to extract the channel boundary lines from the channel region.A non-intelligent angle-based filtering and clustering method is proposed and compared with corner point regression network.The training and evaluation of the segmentation method and corner regression network are carried out on the synthetic and real ice channel dataset.The evaluation results show that the accuracy of the method using the corner point regression network in the second stage is achieved as high as 73.33%on the synthetic ice channel dataset and 70.66%on the real ice channel dataset,and the processing speed can reach up to 14.58frames per second.
基金National Natural Science Foundation of China(Nos.42071444,42101444)。
文摘Cultural relics line graphic serves as a crucial form of traditional artifact information documentation,which is a simple and intuitive product with low cost of displaying compared with 3D models.Dimensionality reduction is undoubtedly necessary for line drawings.However,most existing methods for artifact drawing rely on the principles of orthographic projection that always cannot avoid angle occlusion and data overlapping while the surface of cultural relics is complex.Therefore,conformal mapping was introduced as a dimensionality reduction way to compensate for the limitation of orthographic projection.Based on the given criteria for assessing surface complexity,this paper proposed a three-dimensional feature guideline extraction method for complex cultural relic surfaces.A 2D and 3D combined factor that measured the importance of points on describing surface features,vertex weight,was designed.Then the selection threshold for feature guideline extraction was determined based on the differences between vertex weight and shape index distributions.The feasibility and stability were verified through experiments conducted on real cultural relic surface data.Results demonstrated the ability of the method to address the challenges associated with the automatic generation of line drawings for complex surfaces.The extraction method and the obtained results will be useful for line graphic drawing,displaying and propaganda of cultural relics.
文摘输电线路的关键部位包括塔身、导线、绝缘子、避雷线以及引流线,无人机精细化导航的首要任务是构造输电线路的点云地图并从中分割出上述部位。为解决现有算法在输电线路的绝缘子、引流线等精细结构分割时精度低的问题,通过改进PointNet++算法,提出了一种面向输电线路精细结构的点云分割方法。首先,基于无人机机载激光雷达在现场采集的点云数据,构造了输电线路点云分割数据集;其次,通过对比实验,筛选出在本输电线路场景下合理的数据增强方法,并对数据集进行了数据增强;最后,将自注意力机制以及倒置残差结构和PointNet++相结合,设计了输电线路关键部位点云语义分割算法。实验结果表明:该改进PointNet++算法在全场景输电线路现场点云数据作为输入的前提下,首次实现了对引流线、绝缘子等输电线路中精细结构和导线、杆塔塔身以及输电线路无关背景点的同时分割,平均交并比(mean intersection over union,mIoU)达80.79%,所有类别分割的平均F_(1)值(F1 score)达88.99%。
基金Project supported by the National Natural Science Foundation of China (Grant Nos.12274455,12274459,and 12204533)the National Key R&D Program of China (Grant No.2022YFA1403800)the Beijing Natural Science Foundation (Grant No.Z200005)。
文摘Using angle-resolved photoemission spectroscopy and density functional theory calculations methods,we investigate the electronic structures and topological properties of ternary tellurides NbIrTe_(4),a candidate for type-II Weyl semimetal.We demonstrate the presence of several Fermi arcs connecting their corresponding Weyl points on both termination surfaces of the topological material.Our analysis reveals the existence of Dirac points,in addition to Weyl points,giving both theoretical and experimental evidences of the coexistence of Dirac and Weyl points in a single material.These findings not only confirm NbIrTe_(4) as a unique topological semimetal but also open avenues for exploring novel electronic devices based on its coexisting Dirac and Weyl fermions.
文摘Internet Exchange Point(IXP)is a system that increases network bandwidth performance.Internet exchange points facilitate interconnection among network providers,including Internet Service Providers(ISPs)andContent Delivery Providers(CDNs).To improve service management,Internet exchange point providers have adopted the Software Defined Network(SDN)paradigm.This implementation is known as a Software-Defined Exchange Point(SDX).It improves network providers’operations and management.However,performance issues still exist,particularly with multi-hop topologies.These issues include switch memory costs,packet processing latency,and link failure recovery delays.The paper proposes Enhanced Link Failure Rerouting(ELFR),an improved mechanism for rerouting link failures in software-defined exchange point networks.The proposed mechanism aims to minimize packet processing time for fast link failure recovery and enhance path calculation efficiency while reducing switch storage overhead by exploiting the Programming Protocol-independent Packet Processors(P4)features.The paper presents the proposed mechanisms’efficiency by utilizing advanced algorithms and demonstrating improved performance in packet processing speed,path calculation effectiveness,and switch storage management compared to current mechanisms.The proposed mechanism shows significant improvements,leading to a 37.5%decrease in Recovery Time(RT)and a 33.33%decrease in both Calculation Time(CT)and Computational Overhead(CO)when compared to current mechanisms.The study highlights the effectiveness and resource efficiency of the proposed mechanism in effectively resolving crucial issues inmulti-hop software-defined exchange point networks.
基金supported by the National Key R&D Program of China(Grant Nos.2022YFA1603300 and 2022YFA1603200)the Science Challenge Project(Grant No.TZ2018005)in China+1 种基金the National Natural Science Foundation of China(Grant Nos.11805188 and 12175209)the Laser Fusion Research Center Funds for Young Talents(Grant No.RCFPD6-2022-1).
文摘We present an application of short-pulse laser-generated hard x rays for the diagnosis of indirectly driven double shell targets. Coneinserted double shell targets were imploded through an indirect drive approach on the upgraded SG-II laser facility. Then, based on thepoint-projection hard x-ray radiography technique, time-resolved radiography of the double shell targets, including that of their near-peakcompression, were obtained. The backlighter source was created by the interactions of a high-intensity short pulsed laser with a metalmicrowire target. Images of the target near peak compression were obtained with an Au microwire. In addition, radiation hydrodynamicsimulations were performed, and the target evolution obtained agrees well with the experimental results. Using the radiographic images, arealdensities of the targets were evaluated.
基金partly funded by the Natural Science Foundation of Shandong Province of China (Grant Nos. ZR2021MA091 and ZR2018MA044)Introduction and Cultivation Plan of Youth Innovation Talents for Universities of Shandong Province (Research and Innovation Team on Materials Modification and Optoelectronic Devices at extreme conditions)。
文摘We study the exceptional-point(EP) structure and the associated quantum dynamics in a system consisting of a non-Hermitian qubit and a Hermitian qubit. We find that the system possesses two sets of EPs, which divide the systemparameter space into PT-symmetry unbroken, partially broken and fully broken regimes, each with distinct quantumdynamics characteristics. Particularly, in the partially broken regime, while the PT-symmetry is generally broken in the whole four-dimensional Hilbert space, it is preserved in a two-dimensional subspace such that the quantum dynamics in the subspace are similar to those in the PT-symmetry unbroken regime. In addition, we reveal that the competition between the inter-qubit coupling and the intra-qubit driving gives rise to a complex pattern in the EP variation with system parameters.