Robust teleoperation in image-guided interventions faces critical challenges from latency,deformation,and the quasi-periodic nature of physiological motion.This paper presents a fully integrated,latency-aware visual s...Robust teleoperation in image-guided interventions faces critical challenges from latency,deformation,and the quasi-periodic nature of physiological motion.This paper presents a fully integrated,latency-aware visual servoing system leveraging stereo vision,hand–eye calibration,and learning-based prediction for motion-compensated teleoperation.The system combines a calibrated binocular camera setup,dual robotic arms,and a predictive control loop incorporating Long Short-Term Memory(LSTM)and Temporal Convolutional Network(TCN)models.Through experiments using both in vivo and phantom datasets,we quantitatively assess the prediction accuracy and motion-compensation performance of both models.Results show that TCNs deliver more stable and precise tracking,especially on regular trajectories,while LSTMs exhibit robustness under quasi-periodic dynamics.By matching prediction horizons to system latency,the approach significantly reduces peak and steady-state tracking errors,demonstrating practical feasibility for deploying prediction-augmented servoing in teleoperated surgical.展开更多
Leontopodium alpinum is a traditional alpine medicinal plant,is extensively used in Tibetan and Mongolian medicine.Its applicability in managing febrile epidemics and respiratory conditions requires deeper study,espec...Leontopodium alpinum is a traditional alpine medicinal plant,is extensively used in Tibetan and Mongolian medicine.Its applicability in managing febrile epidemics and respiratory conditions requires deeper study,especially given the recurring threat of infectious diseases.This study uses bibliometric analysis to examine the current state and trends in Leontopodium alpinum research,integrates scattered information,and suggests pathways for subsequent investigation.This study retrieved Chinese literature from the China National Knowledge Infrastructure(CNKI)platform and international literature from the Web of Science(WoS),with data collection finalized by March 2025.CiteSpace 6.3.R1 and VOSviewer 1.6.20 were used to visually analyze publication trends,keyword co-occurrence,and author collaboration networks.The analysis has found that Chinese publications rose markedly after 2003 but declined after 2019,focusing largely on chemical components–such as chlorogenic acid and volatile oils–and pharmacological activities.International output,though smaller,grew steadily,with an emphasis on compositional analysis and antioxidant effects.Keyword clustering revealed that both Chinese and global research expanded from foundational taxonomy to chemical constituents,bioactivity,and environmental adaptation.Core author and institutional analyses identified Liaoning University of Traditional Chinese Medicine and the University of Chinese Academy of Sciences as domestic leaders,while the University of Innsbruck(Austria)played a leading international role.In conclusion,this study offers the first systematic summary of research and publishing trends for Leontopodium alpinum,while also identifying key knowledge gaps.Future studies should prioritize multi-omics approaches to clarify the mechanisms of its bioactive compounds and advance clinical application.Due to its notable efficacy against febrile epidemics and respiratory diseases,expanded research is strongly recommended–particularly in light of rising infectious disease risks where this species could serve an essential role.展开更多
Temporary plugging and diversion fracturing(TPDF)is widely used to promote the uniform and complex distribution of multi-clustered hydraulic fractures(HFs)in a horizontal well of the unconventional formations.However,...Temporary plugging and diversion fracturing(TPDF)is widely used to promote the uniform and complex distribution of multi-clustered hydraulic fractures(HFs)in a horizontal well of the unconventional formations.However,the migration behavior of temporary plugging agent(TPA),as a function of the concentration and particle size of TPA and cluster-perforation numbers,etc.,determining the effectiveness of this technique,remains unclear.Therefore,this study conducted innovatively a series of TPDF simulation experiments on transparent polymethyl methacrylate(PMMA)specimens(cubic block of 30 cm×30 cm×30 cm)to explore visually the migration behavior of TPA in multi-clustered HFs in a horizontal well.A laboratory hydraulic sandblasting perforation completion technique was implemented to simulate the multi-cluster perforations.All the distributions of wellbore,perforations,HFs,and TPA can be seen clearly inside the PMMA specimen post the experiment.The results show that there are four characteristic plugging positions for the TPA:mouth of HF,middle of HF,tip of HF,and the intersection of HFs.Small particle size TPA tends to migrate to the fracture tip for plugging,while large particle size TPA tends to plug at the fracture mouth.The migration of the TPA is influenced obviously by the morphology of the fracture wall.A smooth fracture wall is conducive to the migration of the TPA to the far end of HFs,but not conducive to generating the plugging zone and HF diversion.In contrast,a"leaf vein"fracture of rough wall is conducive to generating the plugging layer and the diversion of HFs,but not conducive to the migration of the TPA to the far end of HFs.The migration ability of TPA in a"shell"pattern is intermediate between the two above cases.Increasing TPA concentration can encourage TPA to migrate more quickly to the characteristic plugging position,and thereby to promote the creation of effective plugging and subsequently the multi-stage diversion of the HFs.Nevertheless,excessive concentration may cause the TPA to settle prematurely,affecting the propagation of the HFs to the far end.Increasing the number of clusters to a certain extent can encourage TPA to migrate into the HFs and form plugging,and promote the diversion.An evaluation system for the migration ability of granular TPA has been established,and it was calculated that when there is no plugging expectation target,the comprehensive migration ability of small particle size TPA is stronger than that of large particle size TPA.This research provides theoretical foundation for the optimization of temporary plugging parameters.展开更多
近年来,深度学习技术在移动机器人同时定位与建图(Simultaneous localization and mapping,SLAM)领域取得了显著进展,为解决传统视觉SLAM在动态环境下面临的挑战提供了新的思路.本文首先总结了传统视觉SLAM在预处理、视觉里程计以及闭...近年来,深度学习技术在移动机器人同时定位与建图(Simultaneous localization and mapping,SLAM)领域取得了显著进展,为解决传统视觉SLAM在动态环境下面临的挑战提供了新的思路.本文首先总结了传统视觉SLAM在预处理、视觉里程计以及闭环检测模块的局限性.随后,聚焦于深度学习在视觉SLAM中的应用,重点介绍了基于深度学习的预处理、视觉里程计和闭环检测模块,以及其如何提升视觉SLAM的鲁棒性和精度.最后,探讨了基于深度学习SLAM面临的挑战并展望了未来研究方向,包括轻量化网络设计、场景的长期建模以及自监督学习等,以推动深度学习SLAM在实际应用中的落地.展开更多
为了解微生物农药产业的发展趋势,利用CiteSpace软件分析了近10年微生物农药研究领域的发展历程、研究热点、新兴趋势及知识结构。结果表明:1)2018年以来,Web of Science核心集数据库(WOS)和中国知网(CNKI)数据库微生物农药研究发文量...为了解微生物农药产业的发展趋势,利用CiteSpace软件分析了近10年微生物农药研究领域的发展历程、研究热点、新兴趋势及知识结构。结果表明:1)2018年以来,Web of Science核心集数据库(WOS)和中国知网(CNKI)数据库微生物农药研究发文量呈持续上升趋势。2)中国、美国和意大利在该领域做出显著贡献并拥有较大影响力。3)研究热点主要集中在害虫抗性治理、诱导系统抗性、胁迫、土壤修复、多样性和可持续农业等方面。4)研究热点不断演化和变动,WOS数据库前期主要围绕害虫抗性治理、多样性和土壤改良展开,后期更加关注微生物-植物-病原菌的互作关系和机制研究;CNKI数据库前期研究集中在菌株筛选和田间效果,后期则更注重产品的推广应用。5)在WOS数据库中,2000—2025年为微生物农药知识基础产出的繁荣期,针对拮抗特性与作用机制的研究处于核心位置,结合微生物组学分析技术,构成了此领域重要的理论和技术基础。未来菌种资源挖掘、菌株改良、机制阐释、发酵工艺和剂型创新将是重点关注方向。本研究结果有助于了解国内外微生物农药研究的发展趋势,为未来微生物农药领域研究提供科学图谱与方向指引。展开更多
在现代制造业迅速发展的背景下,车间调度问题在生产制造中起着重要作用,是确保生产流程顺畅、提高生产效率、降低生产成本的关键环节。为全面系统地分析我国车间调度领域的发展状况和研究动态,通过检索中国知网(CNKI)和Web of Science(W...在现代制造业迅速发展的背景下,车间调度问题在生产制造中起着重要作用,是确保生产流程顺畅、提高生产效率、降低生产成本的关键环节。为全面系统地分析我国车间调度领域的发展状况和研究动态,通过检索中国知网(CNKI)和Web of Science(WOS)数据库,获得2000年~2023年以车间调度为主题的中英文文献共14298篇,再运用CiteSpace 6.3 R1软件对文献进行可视化分析,分别从发文量、研究作者、国家地区、机构、关键词共现和被引文献等不同角度审视研究主题结构,结合可视化知识图谱对车间调度领域的现状、趋势和热点进行分析。分析结果表明,由于车间调度在实际应用中的复杂性和多样性,车间调度领域的研究热点也呈现多元化的趋势,目前该领域的研究主要围绕动态与实时调度的优化、多目标优化的平衡追求和智能化算法的应用等方面展开,智能化、绿色化、可持续化和跨学科融合等是未来的发展方向。展开更多
背景:研究表明,脂代谢及其相关疾病能影响骨质疏松症的发展。目的:运用文献计量学可视化分析软件分析归纳脂代谢影响骨质疏松症领域的前沿内容与研究热点。方法:以Web of Science核心合集数据库为检索平台,检索2004-2024年脂代谢影响骨...背景:研究表明,脂代谢及其相关疾病能影响骨质疏松症的发展。目的:运用文献计量学可视化分析软件分析归纳脂代谢影响骨质疏松症领域的前沿内容与研究热点。方法:以Web of Science核心合集数据库为检索平台,检索2004-2024年脂代谢影响骨质疏松症领域的相关文献,运用VOSviewer和CiteSpace可视化软件进行文献计量与可视化分析。结果与结论:共纳入1277篇文献,国内外关于脂代谢影响骨质疏松症的发文量呈逐年增长趋势,中国发文量417篇居于榜首,美国243篇位居第二。上海交通大学以发文量30篇排名第一,文章产量最高的是塔夫茨大学医学院的Rosen Clifford J教授,克雷顿大学Recker Robert R教授是被引用最多的作者。荷兰的《BONE》杂志发表文献量位居首位,英国的《JOURNAL OF CLINICAL ENDOCRINOLOGY&METABOLISM》杂志为被引次数最多的期刊。骨密度、骨代谢、绝经、肥胖为核心关键词,同时也是该领域的研究热点。近20年来脂代谢影响骨质疏松症领域的研究注重于脂质代谢异常对于骨密度和骨代谢的作用,从而调节骨质疏松症及绝经后骨质疏松症,明确这种机制的作用途径以及“骨脂平衡”是未来的研究思路和方向。展开更多
目的 探讨数字智能化诊疗技术在多次胆道手术史肝胆管结石病诊疗中的应用价值。方法采用回顾性队列研究方法,纳入2017年1月至2024年12月南方医科大学珠江医院行胆道镜联合硬镜取石手术治疗的合并胆道手术史的肝胆管结石病患者,分为3DVT...目的 探讨数字智能化诊疗技术在多次胆道手术史肝胆管结石病诊疗中的应用价值。方法采用回顾性队列研究方法,纳入2017年1月至2024年12月南方医科大学珠江医院行胆道镜联合硬镜取石手术治疗的合并胆道手术史的肝胆管结石病患者,分为3DVT-FI组和常规手术组。收集、分析和比较两组临床数据。结果共纳入63例患者,其中3DVT-FI组33例,常规手术组30例。逆概率加权(inverse probability of treatment weighting,IPTW)后一般资料均差异无统计学意义(P>0.05)。3DVT-FI组的开腹率、术中出血量、术后并发症发生率以及3月内再次手术发生率显著低于常规手术组(均P<0.05)。单因素分析显示术后有和无并发症患者在是否合并肝外胆管结石、手术年份、以及手术方案存在差异(P<0.05)。多因素分析表明无肝外胆管结石(OR=0.105)为术后出现并发症的保护因素,而常规手术方式(OR=3.952)则为其危险因素(均P<0.05)。结论三维可视化联合ICG荧光成像技术运用在多次胆道手术史的肝胆管结石病诊疗中,可以提高手术的微创率和减少术后并发症发生率,该技术的应用提高了多次胆道手术史肝胆管结石病手术治疗的安全和有效性,具有重要的临床价值。展开更多
当前计算机组成原理课程的实验教学,以实体实验箱、基于Logisim和基于FPGA开发板的仿真实验设计为主,这些实验形式分别存在着故障率高、时空受限、缺少直观性、交互性差、设计门槛高和内容抽象等问题。针对存在的问题,课程组基于OBE理念...当前计算机组成原理课程的实验教学,以实体实验箱、基于Logisim和基于FPGA开发板的仿真实验设计为主,这些实验形式分别存在着故障率高、时空受限、缺少直观性、交互性差、设计门槛高和内容抽象等问题。针对存在的问题,课程组基于OBE理念,采用成熟的Unity3D引擎和3D Studio Max等仿真开发技术,设计并实现了计算机组成原理虚拟仿真实验平台。基于仿真实验平台,对实验内容、实验组织形式和考核评价方式等实践教学环节进行了改进,优化了线上线下混合式教学模式。教学实践显示,新的实践教学模式能够提升区分度,在提高学生的学习兴趣和有针对性的持续改进方面,有重要的意义。展开更多
基金Support by Sichuan Science and Technology Program[2023YFSY0026,2023YFH0004]Guangzhou Huashang University[2024HSZD01,HS2023JYSZH01].
文摘Robust teleoperation in image-guided interventions faces critical challenges from latency,deformation,and the quasi-periodic nature of physiological motion.This paper presents a fully integrated,latency-aware visual servoing system leveraging stereo vision,hand–eye calibration,and learning-based prediction for motion-compensated teleoperation.The system combines a calibrated binocular camera setup,dual robotic arms,and a predictive control loop incorporating Long Short-Term Memory(LSTM)and Temporal Convolutional Network(TCN)models.Through experiments using both in vivo and phantom datasets,we quantitatively assess the prediction accuracy and motion-compensation performance of both models.Results show that TCNs deliver more stable and precise tracking,especially on regular trajectories,while LSTMs exhibit robustness under quasi-periodic dynamics.By matching prediction horizons to system latency,the approach significantly reduces peak and steady-state tracking errors,demonstrating practical feasibility for deploying prediction-augmented servoing in teleoperated surgical.
基金supported by the National Key R&D Program of China:Intergovernmental Cooperation in International Science and Technology Innovation(2022YFE0119300)Mongolian Foundation for Science and Technology(MFST-CHN2022/277 and MFST 2022/176)Science and Technology Foundation,Ministry of Environment and Tourism of Mongolia(20BB11ShT3030).
文摘Leontopodium alpinum is a traditional alpine medicinal plant,is extensively used in Tibetan and Mongolian medicine.Its applicability in managing febrile epidemics and respiratory conditions requires deeper study,especially given the recurring threat of infectious diseases.This study uses bibliometric analysis to examine the current state and trends in Leontopodium alpinum research,integrates scattered information,and suggests pathways for subsequent investigation.This study retrieved Chinese literature from the China National Knowledge Infrastructure(CNKI)platform and international literature from the Web of Science(WoS),with data collection finalized by March 2025.CiteSpace 6.3.R1 and VOSviewer 1.6.20 were used to visually analyze publication trends,keyword co-occurrence,and author collaboration networks.The analysis has found that Chinese publications rose markedly after 2003 but declined after 2019,focusing largely on chemical components–such as chlorogenic acid and volatile oils–and pharmacological activities.International output,though smaller,grew steadily,with an emphasis on compositional analysis and antioxidant effects.Keyword clustering revealed that both Chinese and global research expanded from foundational taxonomy to chemical constituents,bioactivity,and environmental adaptation.Core author and institutional analyses identified Liaoning University of Traditional Chinese Medicine and the University of Chinese Academy of Sciences as domestic leaders,while the University of Innsbruck(Austria)played a leading international role.In conclusion,this study offers the first systematic summary of research and publishing trends for Leontopodium alpinum,while also identifying key knowledge gaps.Future studies should prioritize multi-omics approaches to clarify the mechanisms of its bioactive compounds and advance clinical application.Due to its notable efficacy against febrile epidemics and respiratory diseases,expanded research is strongly recommended–particularly in light of rising infectious disease risks where this species could serve an essential role.
基金supported by the National Natural Science Foundation of China Joint Fund for Enterprise Innovation and Development,Enrichment Mechanism and Stereoscopic Development of Shale Oil in Continental Rift Basins(No.U24B6002).
文摘Temporary plugging and diversion fracturing(TPDF)is widely used to promote the uniform and complex distribution of multi-clustered hydraulic fractures(HFs)in a horizontal well of the unconventional formations.However,the migration behavior of temporary plugging agent(TPA),as a function of the concentration and particle size of TPA and cluster-perforation numbers,etc.,determining the effectiveness of this technique,remains unclear.Therefore,this study conducted innovatively a series of TPDF simulation experiments on transparent polymethyl methacrylate(PMMA)specimens(cubic block of 30 cm×30 cm×30 cm)to explore visually the migration behavior of TPA in multi-clustered HFs in a horizontal well.A laboratory hydraulic sandblasting perforation completion technique was implemented to simulate the multi-cluster perforations.All the distributions of wellbore,perforations,HFs,and TPA can be seen clearly inside the PMMA specimen post the experiment.The results show that there are four characteristic plugging positions for the TPA:mouth of HF,middle of HF,tip of HF,and the intersection of HFs.Small particle size TPA tends to migrate to the fracture tip for plugging,while large particle size TPA tends to plug at the fracture mouth.The migration of the TPA is influenced obviously by the morphology of the fracture wall.A smooth fracture wall is conducive to the migration of the TPA to the far end of HFs,but not conducive to generating the plugging zone and HF diversion.In contrast,a"leaf vein"fracture of rough wall is conducive to generating the plugging layer and the diversion of HFs,but not conducive to the migration of the TPA to the far end of HFs.The migration ability of TPA in a"shell"pattern is intermediate between the two above cases.Increasing TPA concentration can encourage TPA to migrate more quickly to the characteristic plugging position,and thereby to promote the creation of effective plugging and subsequently the multi-stage diversion of the HFs.Nevertheless,excessive concentration may cause the TPA to settle prematurely,affecting the propagation of the HFs to the far end.Increasing the number of clusters to a certain extent can encourage TPA to migrate into the HFs and form plugging,and promote the diversion.An evaluation system for the migration ability of granular TPA has been established,and it was calculated that when there is no plugging expectation target,the comprehensive migration ability of small particle size TPA is stronger than that of large particle size TPA.This research provides theoretical foundation for the optimization of temporary plugging parameters.
文摘近年来,深度学习技术在移动机器人同时定位与建图(Simultaneous localization and mapping,SLAM)领域取得了显著进展,为解决传统视觉SLAM在动态环境下面临的挑战提供了新的思路.本文首先总结了传统视觉SLAM在预处理、视觉里程计以及闭环检测模块的局限性.随后,聚焦于深度学习在视觉SLAM中的应用,重点介绍了基于深度学习的预处理、视觉里程计和闭环检测模块,以及其如何提升视觉SLAM的鲁棒性和精度.最后,探讨了基于深度学习SLAM面临的挑战并展望了未来研究方向,包括轻量化网络设计、场景的长期建模以及自监督学习等,以推动深度学习SLAM在实际应用中的落地.
文摘为了解微生物农药产业的发展趋势,利用CiteSpace软件分析了近10年微生物农药研究领域的发展历程、研究热点、新兴趋势及知识结构。结果表明:1)2018年以来,Web of Science核心集数据库(WOS)和中国知网(CNKI)数据库微生物农药研究发文量呈持续上升趋势。2)中国、美国和意大利在该领域做出显著贡献并拥有较大影响力。3)研究热点主要集中在害虫抗性治理、诱导系统抗性、胁迫、土壤修复、多样性和可持续农业等方面。4)研究热点不断演化和变动,WOS数据库前期主要围绕害虫抗性治理、多样性和土壤改良展开,后期更加关注微生物-植物-病原菌的互作关系和机制研究;CNKI数据库前期研究集中在菌株筛选和田间效果,后期则更注重产品的推广应用。5)在WOS数据库中,2000—2025年为微生物农药知识基础产出的繁荣期,针对拮抗特性与作用机制的研究处于核心位置,结合微生物组学分析技术,构成了此领域重要的理论和技术基础。未来菌种资源挖掘、菌株改良、机制阐释、发酵工艺和剂型创新将是重点关注方向。本研究结果有助于了解国内外微生物农药研究的发展趋势,为未来微生物农药领域研究提供科学图谱与方向指引。
文摘在现代制造业迅速发展的背景下,车间调度问题在生产制造中起着重要作用,是确保生产流程顺畅、提高生产效率、降低生产成本的关键环节。为全面系统地分析我国车间调度领域的发展状况和研究动态,通过检索中国知网(CNKI)和Web of Science(WOS)数据库,获得2000年~2023年以车间调度为主题的中英文文献共14298篇,再运用CiteSpace 6.3 R1软件对文献进行可视化分析,分别从发文量、研究作者、国家地区、机构、关键词共现和被引文献等不同角度审视研究主题结构,结合可视化知识图谱对车间调度领域的现状、趋势和热点进行分析。分析结果表明,由于车间调度在实际应用中的复杂性和多样性,车间调度领域的研究热点也呈现多元化的趋势,目前该领域的研究主要围绕动态与实时调度的优化、多目标优化的平衡追求和智能化算法的应用等方面展开,智能化、绿色化、可持续化和跨学科融合等是未来的发展方向。
文摘背景:研究表明,脂代谢及其相关疾病能影响骨质疏松症的发展。目的:运用文献计量学可视化分析软件分析归纳脂代谢影响骨质疏松症领域的前沿内容与研究热点。方法:以Web of Science核心合集数据库为检索平台,检索2004-2024年脂代谢影响骨质疏松症领域的相关文献,运用VOSviewer和CiteSpace可视化软件进行文献计量与可视化分析。结果与结论:共纳入1277篇文献,国内外关于脂代谢影响骨质疏松症的发文量呈逐年增长趋势,中国发文量417篇居于榜首,美国243篇位居第二。上海交通大学以发文量30篇排名第一,文章产量最高的是塔夫茨大学医学院的Rosen Clifford J教授,克雷顿大学Recker Robert R教授是被引用最多的作者。荷兰的《BONE》杂志发表文献量位居首位,英国的《JOURNAL OF CLINICAL ENDOCRINOLOGY&METABOLISM》杂志为被引次数最多的期刊。骨密度、骨代谢、绝经、肥胖为核心关键词,同时也是该领域的研究热点。近20年来脂代谢影响骨质疏松症领域的研究注重于脂质代谢异常对于骨密度和骨代谢的作用,从而调节骨质疏松症及绝经后骨质疏松症,明确这种机制的作用途径以及“骨脂平衡”是未来的研究思路和方向。
文摘目的 探讨数字智能化诊疗技术在多次胆道手术史肝胆管结石病诊疗中的应用价值。方法采用回顾性队列研究方法,纳入2017年1月至2024年12月南方医科大学珠江医院行胆道镜联合硬镜取石手术治疗的合并胆道手术史的肝胆管结石病患者,分为3DVT-FI组和常规手术组。收集、分析和比较两组临床数据。结果共纳入63例患者,其中3DVT-FI组33例,常规手术组30例。逆概率加权(inverse probability of treatment weighting,IPTW)后一般资料均差异无统计学意义(P>0.05)。3DVT-FI组的开腹率、术中出血量、术后并发症发生率以及3月内再次手术发生率显著低于常规手术组(均P<0.05)。单因素分析显示术后有和无并发症患者在是否合并肝外胆管结石、手术年份、以及手术方案存在差异(P<0.05)。多因素分析表明无肝外胆管结石(OR=0.105)为术后出现并发症的保护因素,而常规手术方式(OR=3.952)则为其危险因素(均P<0.05)。结论三维可视化联合ICG荧光成像技术运用在多次胆道手术史的肝胆管结石病诊疗中,可以提高手术的微创率和减少术后并发症发生率,该技术的应用提高了多次胆道手术史肝胆管结石病手术治疗的安全和有效性,具有重要的临床价值。
文摘当前计算机组成原理课程的实验教学,以实体实验箱、基于Logisim和基于FPGA开发板的仿真实验设计为主,这些实验形式分别存在着故障率高、时空受限、缺少直观性、交互性差、设计门槛高和内容抽象等问题。针对存在的问题,课程组基于OBE理念,采用成熟的Unity3D引擎和3D Studio Max等仿真开发技术,设计并实现了计算机组成原理虚拟仿真实验平台。基于仿真实验平台,对实验内容、实验组织形式和考核评价方式等实践教学环节进行了改进,优化了线上线下混合式教学模式。教学实践显示,新的实践教学模式能够提升区分度,在提高学生的学习兴趣和有针对性的持续改进方面,有重要的意义。
