This paper presents our endeavors in developing the large-scale, ultra-high-resolution E3SM Land Model (uELM), specifically designed for exascale computers furnished with accelerators such as Nvidia GPUs. The uELM is ...This paper presents our endeavors in developing the large-scale, ultra-high-resolution E3SM Land Model (uELM), specifically designed for exascale computers furnished with accelerators such as Nvidia GPUs. The uELM is a sophisticated code that substantially relies on High-Performance Computing (HPC) environments, necessitating particular machine and software configurations. To facilitate community-based uELM developments employing GPUs, we have created a portable, standalone software environment preconfigured with uELM input datasets, simulation cases, and source code. This environment, utilizing Docker, encompasses all essential code, libraries, and system software for uELM development on GPUs. It also features a functional unit test framework and an offline model testbed for comprehensive numerical experiments. From a technical perspective, the paper discusses GPU-ready container generations, uELM code management, and input data distribution across computational platforms. Lastly, the paper demonstrates the use of environment for functional unit testing, end-to-end simulation on CPUs and GPUs, and collaborative code development.展开更多
软件定义自组网(Software Defined Mobile Ad Hoc Network,SD-MANET)融合了软件定义网络(Software Defined Network,SDN)集中控制优势和移动自组网(Mobile Ad Hoc Network,MANET)的动态组网优势,但Mininet等现有仿真平台在动态拓扑与扩...软件定义自组网(Software Defined Mobile Ad Hoc Network,SD-MANET)融合了软件定义网络(Software Defined Network,SDN)集中控制优势和移动自组网(Mobile Ad Hoc Network,MANET)的动态组网优势,但Mininet等现有仿真平台在动态拓扑与扩展性等方面存在显著局限,严重制约了其关键算法的研究。针对这一问题,提出基于网络模拟器-3(Network Simulator-3,NS-3)的仿真平台NS3-SDMANET,具体工作包括:基于NS-3框架实现了SD-MANET网络层关键特性的仿真;基于远程过程调用对平台功能进行封装,并提供可编程接口。战术网的测试案例表明:NS3-SDMANET在SD-MANET网络层关键特性仿真方面表现优异,能够有效支撑SD-MANET网络层算法的高效验证与性能评估,为相关研究提供了高扩展性的基础仿真环境。展开更多
The development of digital intelligent diagnostic and treatment technology has opened countless new opportunities for liver surgery from the era of digital anatomy to a new era of digital diagnostics,virtual surgery s...The development of digital intelligent diagnostic and treatment technology has opened countless new opportunities for liver surgery from the era of digital anatomy to a new era of digital diagnostics,virtual surgery simulation and using the created scenarios in real-time surgery using mixed reality.In this article,we described our experience on developing a dedicated 3 dimensional visualization and reconstruction software for surgeons to be used in advanced liver surgery and living donor liver transplantation.Furthermore,we shared the recent developments in the field by explaining the outreach of the software from virtual reality to augmented reality and mixed reality.展开更多
In order to improve the efficiency of embedded software running on processor core, this paper proposes a hard-ware/software co-optimization approach for embedded software from the system point of view. The proposed st...In order to improve the efficiency of embedded software running on processor core, this paper proposes a hard-ware/software co-optimization approach for embedded software from the system point of view. The proposed stepwise methods aim at exploiting the structure and the resources of the processor as much as possible for software algorithm optimization. To achieve low memory usage and low frequency need for the same performance, this co-optimization approach was used to optimize embedded software of MP3 decoder based on a 16-bit fixed-point DSP core. After the optimization, the results of decoding 128 kbps, 44.1 kHz stereo MP3 on DSP evaluation platform need 45.9 MIPS and 20.4 kbytes memory space. The optimization rate achieves 65.6% for memory and 49.6% for frequency respectively compared with the results by compiler using floating-point computation. The experimental result indicates the availability of the hardware/software co-optimization approach depending on the algorithm and architecture.展开更多
The paper researched and analyzed the characteristics, deficiencies and reasons of a management system of a software enterprise project to design a software project management system based on CMMI 1.2, thus helping th...The paper researched and analyzed the characteristics, deficiencies and reasons of a management system of a software enterprise project to design a software project management system based on CMMI 1.2, thus helping the enterprise to improve development and management efficiency of software project and reduce the risks and costs on project devel- opment. It studied CMMI model version 1.3 which is recently released by SEI, analyzed its characteristics and told the difference between version 1.2 and version 1.3. In addition, an improvement proposal and a solution of the software project management system were given from multiple perspectives.展开更多
The cultivation of innovative and entrepreneurial capability is a quality requirement of the times for the training of college and university talents. However, the regular teaching system universally has such problems...The cultivation of innovative and entrepreneurial capability is a quality requirement of the times for the training of college and university talents. However, the regular teaching system universally has such problems as much more emphasis on theory than on practice, much more emphasis on inheritance than on innovation, and mismatching between talent training and market demand, so that a great number of graduates do not have enough innovative capacity, and it is very difficult for them to engage in related jobs of software engineering steadily and permanently. By investigating and analyzing similar majors of more than 20 schools at home and abroad, this article proposes a teaching system of talent training of the 3 C-cored major of "innovative and entrepreneurial" software engineering(digital media technology) based on regions, oriented to the industry and marked by school-enterprise linkage, and in connection with the characteristics of college and university education.展开更多
This paper suggests a component-based software development framework for 3rd party logistics (3PL) business. This framework integrates two engineering methodologies in order to identify the most reusable software comp...This paper suggests a component-based software development framework for 3rd party logistics (3PL) business. This framework integrates two engineering methodologies in order to identify the most reusable software components that can be used in several types of 3PL business models. UML (Unified Modeling Language) is used to design lower-level software components and DEMO (Design and Engineering Methodology for Organization), one of the business engineering methodologies based on the communication theory, is used to identify core business processes for 3PL business models. By using the methodologies, we develop a 3PL management solution by applying the framework into a C2C type of 3PL business model, specifically the door-to-door (D2D) service.展开更多
Purpose: To clarify the effectiveness of 3-D delivery animation software for the mother’s and husband’s satisfaction with delivery. Subjects and Method: We independently developed a software application used to disp...Purpose: To clarify the effectiveness of 3-D delivery animation software for the mother’s and husband’s satisfaction with delivery. Subjects and Method: We independently developed a software application used to display the pelvic region and explain the labor process. The study involved a collaboration with hospital staff who recruited 18 primiparous and 18 multiparous mothers who were hospitalized for delivery at Facility A. The midwife explained the process of delivery using the “Delivery Animation Software”. A self-administered, anonymous questionnaire was distributed and analyzed separately for primiparous and multiparous mothers and their husbands. Results: 1) For both primiparous and multiparous couples, both mothers and their husbands gained a significantly higher level of understanding after delivery than during pregnancy. 2) The Self-Evaluation Scale for Experience of Delivery results were as follows: “I did my best for the baby even if it was painful” was selected more often for “birth coping skills”;“reliable medical staff” was selected more often for “physiological birth process”;“the birth progressed as I expected” was selected frequently by primiparous mothers;and “the birth progressed smoothly” was selected often by multiparous mothers. 3) In terms of husbands’ satisfaction with the delivery, “I was satisfied with the delivery”, “I was given an easy-to-understand explanation”, and “They explained the process to me” was selected of primiparous and multiparous fathers. 4) All primiparous and multiparous mothers positively evaluated whether the delivery animation was helpful in understanding the process of delivery. Conclusion: The delivery animation was effective in improving the understanding and satisfaction of both the mothers and their husbands.展开更多
Background: Non-uniformity in signal intensity occurs commonly in magnetic resonance (MR) imaging, which may pose substantial problems when using a 3T scanner. Therefore, image non-uniformity correction is usually app...Background: Non-uniformity in signal intensity occurs commonly in magnetic resonance (MR) imaging, which may pose substantial problems when using a 3T scanner. Therefore, image non-uniformity correction is usually applied. Purpose: To compare the correction effects of the phased-array uniformity enhancement (PURE), a calibration-based image non-uniformity correction method, among three different software versions in 3T Gd-EOB-DTPA-enhanced MR imaging. Material and Methods: Hepatobiliary-phase images of a total of 120 patients who underwent Gd-EOB-DTPA-enhanced MR imaging on the same 3T scanner were analyzed retrospectively. Forty patients each were examined using three software versions (DV25, DV25.1, and DV26). The effects of PURE were compared by visual assessment, histogram analysis of liver signal intensity, evaluation of the spatial distribution of correction effects, and evaluation of quantitative indices of liver parenchymal enhancement. Results: The visual assessment indicated the highest uniformity of PURE-corrected images for DV26, followed by DV25 and DV25.1. Histogram analysis of corrected images demonstrated significantly larger variations in liver signal for DV25.1 than for the other two versions. Although PURE caused a relative increase in pixel values for central and lateral regions, such effects were weaker for DV25.1 than for the other two versions. In the evaluation of quantitative indices of liver parenchymal enhancement, the liver-to-muscle ratio (LMR) was significantly higher for the corrected images than for the uncorrected images, but the liver-to-spleen ratio (LSR) showed no significant differences. For corrected images, the LMR was significantly higher for DV25 and DV26 than for DV25.1, but the LSR showed no significant differences among the three versions. Conclusion: There were differences in the effects of PURE among the three software versions in 3T Gd-EOB-DTPA-enhanced MR imaging. Even if the non-uniformity correction method has the same brand name, correction effects may differ depending on the software version, and these differences may affect visual and quantitative evaluations.展开更多
Understanding skyrmion–skyrmion interactions and their dynamical effects is crucial for skyrmion-based applications.In this article,we investigate the deformation of skyrmions induced by the inter-skyrmion interactio...Understanding skyrmion–skyrmion interactions and their dynamical effects is crucial for skyrmion-based applications.In this article,we investigate the deformation of skyrmions induced by the inter-skyrmion interaction in both static and dynamic scenarios for a two-skyrmion system.In the static case under a pinning magnetic field,the inter-skyrmion interaction energy decreases rapidly with increasing separation between the skyrmions,while their individual sizes grow.The semiaxis ratio of the elliptical skyrmion exhibits non-monotonic behavior,owing to the competition between skyrmion–skyrmion interactions and pinning effects.In dynamic simulations after removing the external pinning field,the two skyrmions spiral away from each other with increasing separation.Following a rapid relaxation period after magnetic field withdrawal,their semiaxis ratio typically increases with distance and the skyrmions gradually approach a perfect circular shape.These findings provide valuable insights into the behavior and interactions of two-skyrmion systems.展开更多
We study the stability and dynamic behaviors of skyrmions in magnetic nanotubes,where curvature and cylindrical symmetry provide unique mechanisms for skyrmion formation and control.Unlike planar geometries,skyrmions ...We study the stability and dynamic behaviors of skyrmions in magnetic nanotubes,where curvature and cylindrical symmetry provide unique mechanisms for skyrmion formation and control.Unlike planar geometries,skyrmions confined in nanotubes exhibit elliptical shapes,stabilized through the interplay of curvature-induced effects,Dzyaloshinskii-Moriya interaction(DMI),and magnetic anisotropy.Using micromagnetic simulations,we construct phase diagrams of skyrmion stability as functions of DMI strength and anisotropy,identifying transitions to saturated or helical configurations in unstable regimes.The dynamics reveal distinct counterclockwise gyration modes,strongly influenced by tube geometry and applied microwave fields.We find that external magnetic fields significantly enhance the azimuthal velocity(v_(φ))while maintaining a consistent axial motion(v_(z))along the-z-direction.Furthermore,transitions between gyration and linear translation modes emerge,governed by the combined effects of magnetic field,DMI,and curvature.Notably,the skyrmion's motion direction depends on the excitation mode and DMI sign,while curvature-modified spin textures produce effective fields without conventional pinning.These results demonstrate that magnetic nanotubes offer a robust and tunable platform for skyrmion manipulation,with potential applications in next-generation memory and logic devices.Our findings also highlight the role of curvature in enabling stable and controllable topological spin textures for advanced spintronic technologies.展开更多
To better understand the biological structure of bigeye tuna(Thunnus obesus),albacore tuna(Thunnus alalunga),and longtail tuna(Thunnus tonggol),computed tomography(CT)was used to scan their bodies,and the data are pro...To better understand the biological structure of bigeye tuna(Thunnus obesus),albacore tuna(Thunnus alalunga),and longtail tuna(Thunnus tonggol),computed tomography(CT)was used to scan their bodies,and the data are processed by Mimics software.The skeleton,swim bladder,and muscle of the three tuna species are reconstructed in three dimensions.The surface area and volume of the corresponding parts are measured.The results show that the surface areas of the skeleton of longtail tuna,bigeye tuna,albacore tuna accounted for 28.18%,37.34%,33.45%of their whole body surface areas respectively;the surface areas of swim bladder accounted for 0,2.06%,2.72% of their whole body surface area respectively;and the surface areas of muscle accounted for 71.82%,60.6%,63.83%of their whole body surface areas respectively.And the volumes of skeleton accounted for 28.18%,8.05%,3.84%,the volumes of swim bladder accounted for 0,3.44%,0.92%,and the volumes of muscle accounted for 94.84%,88.51%,95.24%of their body volumes respectively.The swim bladder of the longtail tuna has degenerated,while that of the bigeye tuna is conical,exhibiting the highest volume proportion among the three species.In contrast,the swim bladder of the albacore tuna is both flat and elongated,resembling an arc.Additionally,the surface area and the volume of the bigeye tuna’s swim bladder differ signifi-cantly from those of the albacore tuna.Regarding skeletal and muscular structures,the bigeye tuna has the highest skeletal volume proportion(8.05%),whereas the albacore tuna exhibits the highest muscle volume proportion(95.24%).These morphological differences are closely associated with their respective habitats.This study demonstrates the potential of CT technology in fish morphological research,providing a reliable,non-invasive method for analyzing internal structures,quantifying organ characteristics and improving the accuracy of acoustic stock assessment.展开更多
REST(Rust-based electronic structure toolkit)is a modern open-source electronic structure code entirely written in Rust,combining high performance,memory safety,and expressive concurrency.As a community-driven project...REST(Rust-based electronic structure toolkit)is a modern open-source electronic structure code entirely written in Rust,combining high performance,memory safety,and expressive concurrency.As a community-driven project,its source code is freely available at https://gitee.com/restgroup,fostering open collaboration and transparent development.It supports a wide range of density functional methods-from local density approximation(LDA),generalized gradient approximation(GGA),meta-GGA,and hybrids to doubly hybrids,as well as machine learning-augmented functionals-enabling high-accuracy simulations with low computational overhead.Its“disk-free”RI-based(RI:resolution-of-the-identity)implementation and efficient shared-memory parallelism(via Rayon)ensure rapid calculations even for challenging systems.REST also of-fers unique user support through large language model-assisted input generation and develop-erfriendly tensor libraries for rapid algorithm prototyping.展开更多
针对北斗三号卫星导航系统(BeiDou-3 Navigation Satellite System,BDS-3)非组合精密单点定位(uncombined precise point positioning,UPPP)解算过程中,接收机天线相位中心变化(phase center variations,PCV)对UPPP解算参数的影响进行...针对北斗三号卫星导航系统(BeiDou-3 Navigation Satellite System,BDS-3)非组合精密单点定位(uncombined precise point positioning,UPPP)解算过程中,接收机天线相位中心变化(phase center variations,PCV)对UPPP解算参数的影响进行了研究.选择武汉大学IGS数据中心最终产品,以BRUX测站为例分析了2024年年积日第90~96天共1周数据解算的坐标精度、天顶对流层延迟(zenith tropospheric delay,ZTD)精度、接收机钟差精度以及斜向电离层电子总量(slant total electron content,STEC)并进行实验对比.结果表明:毫米级PCV误差对高程方向影响较大,对水平方向影响较小;PCV对钟差结果影响较大,有无PCV误差改正,其结果相差约2 ns(约0.6 m);PCV误差对ZTD影响较大,未校正PCV误差ZTD精度为15.7 mm,进行PCV误差校正后ZTD精度为7.6 mm,精度提升两倍左右;PCV误差在UPPP收敛阶段对STEC影响较大,可达0.3 TECU(约0.047 m),收敛后对STEC影响基本可以忽略.展开更多
文摘This paper presents our endeavors in developing the large-scale, ultra-high-resolution E3SM Land Model (uELM), specifically designed for exascale computers furnished with accelerators such as Nvidia GPUs. The uELM is a sophisticated code that substantially relies on High-Performance Computing (HPC) environments, necessitating particular machine and software configurations. To facilitate community-based uELM developments employing GPUs, we have created a portable, standalone software environment preconfigured with uELM input datasets, simulation cases, and source code. This environment, utilizing Docker, encompasses all essential code, libraries, and system software for uELM development on GPUs. It also features a functional unit test framework and an offline model testbed for comprehensive numerical experiments. From a technical perspective, the paper discusses GPU-ready container generations, uELM code management, and input data distribution across computational platforms. Lastly, the paper demonstrates the use of environment for functional unit testing, end-to-end simulation on CPUs and GPUs, and collaborative code development.
文摘软件定义自组网(Software Defined Mobile Ad Hoc Network,SD-MANET)融合了软件定义网络(Software Defined Network,SDN)集中控制优势和移动自组网(Mobile Ad Hoc Network,MANET)的动态组网优势,但Mininet等现有仿真平台在动态拓扑与扩展性等方面存在显著局限,严重制约了其关键算法的研究。针对这一问题,提出基于网络模拟器-3(Network Simulator-3,NS-3)的仿真平台NS3-SDMANET,具体工作包括:基于NS-3框架实现了SD-MANET网络层关键特性的仿真;基于远程过程调用对平台功能进行封装,并提供可编程接口。战术网的测试案例表明:NS3-SDMANET在SD-MANET网络层关键特性仿真方面表现优异,能够有效支撑SD-MANET网络层算法的高效验证与性能评估,为相关研究提供了高扩展性的基础仿真环境。
文摘The development of digital intelligent diagnostic and treatment technology has opened countless new opportunities for liver surgery from the era of digital anatomy to a new era of digital diagnostics,virtual surgery simulation and using the created scenarios in real-time surgery using mixed reality.In this article,we described our experience on developing a dedicated 3 dimensional visualization and reconstruction software for surgeons to be used in advanced liver surgery and living donor liver transplantation.Furthermore,we shared the recent developments in the field by explaining the outreach of the software from virtual reality to augmented reality and mixed reality.
基金Project supported by the Key-Tech Program of Zhejiang Province,China (No. 021101559), and the Fok Ying Tong Education Founda-tion (No. 94031), China
文摘In order to improve the efficiency of embedded software running on processor core, this paper proposes a hard-ware/software co-optimization approach for embedded software from the system point of view. The proposed stepwise methods aim at exploiting the structure and the resources of the processor as much as possible for software algorithm optimization. To achieve low memory usage and low frequency need for the same performance, this co-optimization approach was used to optimize embedded software of MP3 decoder based on a 16-bit fixed-point DSP core. After the optimization, the results of decoding 128 kbps, 44.1 kHz stereo MP3 on DSP evaluation platform need 45.9 MIPS and 20.4 kbytes memory space. The optimization rate achieves 65.6% for memory and 49.6% for frequency respectively compared with the results by compiler using floating-point computation. The experimental result indicates the availability of the hardware/software co-optimization approach depending on the algorithm and architecture.
文摘The paper researched and analyzed the characteristics, deficiencies and reasons of a management system of a software enterprise project to design a software project management system based on CMMI 1.2, thus helping the enterprise to improve development and management efficiency of software project and reduce the risks and costs on project devel- opment. It studied CMMI model version 1.3 which is recently released by SEI, analyzed its characteristics and told the difference between version 1.2 and version 1.3. In addition, an improvement proposal and a solution of the software project management system were given from multiple perspectives.
基金supported by Research and Practice on the reform of graduate education and teaching in Jiangsu Province in 2016(JGZZ16_065)
文摘The cultivation of innovative and entrepreneurial capability is a quality requirement of the times for the training of college and university talents. However, the regular teaching system universally has such problems as much more emphasis on theory than on practice, much more emphasis on inheritance than on innovation, and mismatching between talent training and market demand, so that a great number of graduates do not have enough innovative capacity, and it is very difficult for them to engage in related jobs of software engineering steadily and permanently. By investigating and analyzing similar majors of more than 20 schools at home and abroad, this article proposes a teaching system of talent training of the 3 C-cored major of "innovative and entrepreneurial" software engineering(digital media technology) based on regions, oriented to the industry and marked by school-enterprise linkage, and in connection with the characteristics of college and university education.
文摘This paper suggests a component-based software development framework for 3rd party logistics (3PL) business. This framework integrates two engineering methodologies in order to identify the most reusable software components that can be used in several types of 3PL business models. UML (Unified Modeling Language) is used to design lower-level software components and DEMO (Design and Engineering Methodology for Organization), one of the business engineering methodologies based on the communication theory, is used to identify core business processes for 3PL business models. By using the methodologies, we develop a 3PL management solution by applying the framework into a C2C type of 3PL business model, specifically the door-to-door (D2D) service.
文摘Purpose: To clarify the effectiveness of 3-D delivery animation software for the mother’s and husband’s satisfaction with delivery. Subjects and Method: We independently developed a software application used to display the pelvic region and explain the labor process. The study involved a collaboration with hospital staff who recruited 18 primiparous and 18 multiparous mothers who were hospitalized for delivery at Facility A. The midwife explained the process of delivery using the “Delivery Animation Software”. A self-administered, anonymous questionnaire was distributed and analyzed separately for primiparous and multiparous mothers and their husbands. Results: 1) For both primiparous and multiparous couples, both mothers and their husbands gained a significantly higher level of understanding after delivery than during pregnancy. 2) The Self-Evaluation Scale for Experience of Delivery results were as follows: “I did my best for the baby even if it was painful” was selected more often for “birth coping skills”;“reliable medical staff” was selected more often for “physiological birth process”;“the birth progressed as I expected” was selected frequently by primiparous mothers;and “the birth progressed smoothly” was selected often by multiparous mothers. 3) In terms of husbands’ satisfaction with the delivery, “I was satisfied with the delivery”, “I was given an easy-to-understand explanation”, and “They explained the process to me” was selected of primiparous and multiparous fathers. 4) All primiparous and multiparous mothers positively evaluated whether the delivery animation was helpful in understanding the process of delivery. Conclusion: The delivery animation was effective in improving the understanding and satisfaction of both the mothers and their husbands.
文摘Background: Non-uniformity in signal intensity occurs commonly in magnetic resonance (MR) imaging, which may pose substantial problems when using a 3T scanner. Therefore, image non-uniformity correction is usually applied. Purpose: To compare the correction effects of the phased-array uniformity enhancement (PURE), a calibration-based image non-uniformity correction method, among three different software versions in 3T Gd-EOB-DTPA-enhanced MR imaging. Material and Methods: Hepatobiliary-phase images of a total of 120 patients who underwent Gd-EOB-DTPA-enhanced MR imaging on the same 3T scanner were analyzed retrospectively. Forty patients each were examined using three software versions (DV25, DV25.1, and DV26). The effects of PURE were compared by visual assessment, histogram analysis of liver signal intensity, evaluation of the spatial distribution of correction effects, and evaluation of quantitative indices of liver parenchymal enhancement. Results: The visual assessment indicated the highest uniformity of PURE-corrected images for DV26, followed by DV25 and DV25.1. Histogram analysis of corrected images demonstrated significantly larger variations in liver signal for DV25.1 than for the other two versions. Although PURE caused a relative increase in pixel values for central and lateral regions, such effects were weaker for DV25.1 than for the other two versions. In the evaluation of quantitative indices of liver parenchymal enhancement, the liver-to-muscle ratio (LMR) was significantly higher for the corrected images than for the uncorrected images, but the liver-to-spleen ratio (LSR) showed no significant differences. For corrected images, the LMR was significantly higher for DV25 and DV26 than for DV25.1, but the LSR showed no significant differences among the three versions. Conclusion: There were differences in the effects of PURE among the three software versions in 3T Gd-EOB-DTPA-enhanced MR imaging. Even if the non-uniformity correction method has the same brand name, correction effects may differ depending on the software version, and these differences may affect visual and quantitative evaluations.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12175180,11934015,and12247103,Shaanxi Fundamental Science Research Project for Mathematics and Physics(Grant Nos.22JSZ005 and22JSQ041)the Natural Science Basic Research Program of Shaanxi Province,China(Grant No.2024JC-YBMS-022)。
文摘Understanding skyrmion–skyrmion interactions and their dynamical effects is crucial for skyrmion-based applications.In this article,we investigate the deformation of skyrmions induced by the inter-skyrmion interaction in both static and dynamic scenarios for a two-skyrmion system.In the static case under a pinning magnetic field,the inter-skyrmion interaction energy decreases rapidly with increasing separation between the skyrmions,while their individual sizes grow.The semiaxis ratio of the elliptical skyrmion exhibits non-monotonic behavior,owing to the competition between skyrmion–skyrmion interactions and pinning effects.In dynamic simulations after removing the external pinning field,the two skyrmions spiral away from each other with increasing separation.Following a rapid relaxation period after magnetic field withdrawal,their semiaxis ratio typically increases with distance and the skyrmions gradually approach a perfect circular shape.These findings provide valuable insights into the behavior and interactions of two-skyrmion systems.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1405900)the National Natural Science Foundation of China(Grant Nos.U2441217 and 12074058)Sichuan Science and Technology Program(Grant No.2024YFHZ0372)。
文摘We study the stability and dynamic behaviors of skyrmions in magnetic nanotubes,where curvature and cylindrical symmetry provide unique mechanisms for skyrmion formation and control.Unlike planar geometries,skyrmions confined in nanotubes exhibit elliptical shapes,stabilized through the interplay of curvature-induced effects,Dzyaloshinskii-Moriya interaction(DMI),and magnetic anisotropy.Using micromagnetic simulations,we construct phase diagrams of skyrmion stability as functions of DMI strength and anisotropy,identifying transitions to saturated or helical configurations in unstable regimes.The dynamics reveal distinct counterclockwise gyration modes,strongly influenced by tube geometry and applied microwave fields.We find that external magnetic fields significantly enhance the azimuthal velocity(v_(φ))while maintaining a consistent axial motion(v_(z))along the-z-direction.Furthermore,transitions between gyration and linear translation modes emerge,governed by the combined effects of magnetic field,DMI,and curvature.Notably,the skyrmion's motion direction depends on the excitation mode and DMI sign,while curvature-modified spin textures produce effective fields without conventional pinning.These results demonstrate that magnetic nanotubes offer a robust and tunable platform for skyrmion manipulation,with potential applications in next-generation memory and logic devices.Our findings also highlight the role of curvature in enabling stable and controllable topological spin textures for advanced spintronic technologies.
基金funded by the National Key R&D Pro-gram(No.2023YFD2401301)the R&D Program of CNFC Overseas Fishery Co.,Ltd.(No.COFC-C-F-2024-004).
文摘To better understand the biological structure of bigeye tuna(Thunnus obesus),albacore tuna(Thunnus alalunga),and longtail tuna(Thunnus tonggol),computed tomography(CT)was used to scan their bodies,and the data are processed by Mimics software.The skeleton,swim bladder,and muscle of the three tuna species are reconstructed in three dimensions.The surface area and volume of the corresponding parts are measured.The results show that the surface areas of the skeleton of longtail tuna,bigeye tuna,albacore tuna accounted for 28.18%,37.34%,33.45%of their whole body surface areas respectively;the surface areas of swim bladder accounted for 0,2.06%,2.72% of their whole body surface area respectively;and the surface areas of muscle accounted for 71.82%,60.6%,63.83%of their whole body surface areas respectively.And the volumes of skeleton accounted for 28.18%,8.05%,3.84%,the volumes of swim bladder accounted for 0,3.44%,0.92%,and the volumes of muscle accounted for 94.84%,88.51%,95.24%of their body volumes respectively.The swim bladder of the longtail tuna has degenerated,while that of the bigeye tuna is conical,exhibiting the highest volume proportion among the three species.In contrast,the swim bladder of the albacore tuna is both flat and elongated,resembling an arc.Additionally,the surface area and the volume of the bigeye tuna’s swim bladder differ signifi-cantly from those of the albacore tuna.Regarding skeletal and muscular structures,the bigeye tuna has the highest skeletal volume proportion(8.05%),whereas the albacore tuna exhibits the highest muscle volume proportion(95.24%).These morphological differences are closely associated with their respective habitats.This study demonstrates the potential of CT technology in fish morphological research,providing a reliable,non-invasive method for analyzing internal structures,quantifying organ characteristics and improving the accuracy of acoustic stock assessment.
基金supported by the National Natural Science Foundation of China (Nos. 22125301, 22393911, 22393912, 22321003, 22233002)the Innovation Program for Quantum Science and Technology (2021ZD0303305)the robotic AI-Scientist platform of the Chinese Academy of Science。
文摘REST(Rust-based electronic structure toolkit)is a modern open-source electronic structure code entirely written in Rust,combining high performance,memory safety,and expressive concurrency.As a community-driven project,its source code is freely available at https://gitee.com/restgroup,fostering open collaboration and transparent development.It supports a wide range of density functional methods-from local density approximation(LDA),generalized gradient approximation(GGA),meta-GGA,and hybrids to doubly hybrids,as well as machine learning-augmented functionals-enabling high-accuracy simulations with low computational overhead.Its“disk-free”RI-based(RI:resolution-of-the-identity)implementation and efficient shared-memory parallelism(via Rayon)ensure rapid calculations even for challenging systems.REST also of-fers unique user support through large language model-assisted input generation and develop-erfriendly tensor libraries for rapid algorithm prototyping.
文摘针对北斗三号卫星导航系统(BeiDou-3 Navigation Satellite System,BDS-3)非组合精密单点定位(uncombined precise point positioning,UPPP)解算过程中,接收机天线相位中心变化(phase center variations,PCV)对UPPP解算参数的影响进行了研究.选择武汉大学IGS数据中心最终产品,以BRUX测站为例分析了2024年年积日第90~96天共1周数据解算的坐标精度、天顶对流层延迟(zenith tropospheric delay,ZTD)精度、接收机钟差精度以及斜向电离层电子总量(slant total electron content,STEC)并进行实验对比.结果表明:毫米级PCV误差对高程方向影响较大,对水平方向影响较小;PCV对钟差结果影响较大,有无PCV误差改正,其结果相差约2 ns(约0.6 m);PCV误差对ZTD影响较大,未校正PCV误差ZTD精度为15.7 mm,进行PCV误差校正后ZTD精度为7.6 mm,精度提升两倍左右;PCV误差在UPPP收敛阶段对STEC影响较大,可达0.3 TECU(约0.047 m),收敛后对STEC影响基本可以忽略.
