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基于CiteSpace及VOSviewer对乳腺癌中PI3K/Akt/mTOR信号通路的可视化分析
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作者 沈继伟 王智 +4 位作者 傅浩栋 车晋 高俊峰 刘举 陈烨 《辽宁大学学报(自然科学版)》 CAS 2024年第1期33-44,共12页
目的:采用文献计量学方法分析乳腺癌中磷脂酰肌醇3-激酶/蛋白激酶B/哺乳动物雷帕霉素靶蛋白(PI3K/Akt/mTOR)信号通路的研究现状与发展趋势,为后续乳腺癌的治疗提供新的思路.方法:通过Web of Science检索自2003年1月1日至2022年6月30日... 目的:采用文献计量学方法分析乳腺癌中磷脂酰肌醇3-激酶/蛋白激酶B/哺乳动物雷帕霉素靶蛋白(PI3K/Akt/mTOR)信号通路的研究现状与发展趋势,为后续乳腺癌的治疗提供新的思路.方法:通过Web of Science检索自2003年1月1日至2022年6月30日乳腺癌中PI3K/Akt/mTOR信号通路的相关文献,本文采用文献计量学进行数据挖掘,借助CiteSpace 6.1R2和VOSviewer软件进行数据分析和可视化分析.结果:共检索1 209篇文章.近年来,有关乳腺癌中PI3K/Akt/mTOR信号通路的发文量波动上升,以KurzrockRazelle为代表的美国作者最为高产,高频关键词有乳腺癌、表达和PI3K/Akt/mTOR信号通路等,共形成了包括内分泌耐药在内的15个聚类,其中肿瘤微环境、细胞周期阻滞和mTOR信号通路是近两年的研究趋势.结论:PI3K/Akt/mTOR信号通路在乳腺癌的治疗中扮演着重要角色,靶向PI3K/Akt/mTOR信号通路抑制剂的研究是治疗乳腺癌的研究重点. 展开更多
关键词 乳腺癌 PI3k/AkT/MTOR CITEspace VOSviewer 可视化分析
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BIG HANKEL OPERATORS ON HARDY SPACES OF STRONGLY PSEUDOCONVEX DOMAINS
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作者 陈伯勇 江良英 《Acta Mathematica Scientia》 SCIE CSCD 2024年第3期789-809,共21页
In this article,we investigate the(big) Hankel operator H_(f) on the Hardy spaces of bounded strongly pseudoconvex domains Ω in C^(n).We observe that H_(f ) is bounded on H~p(Ω)(1 <p <∞) if f belongs to BMO a... In this article,we investigate the(big) Hankel operator H_(f) on the Hardy spaces of bounded strongly pseudoconvex domains Ω in C^(n).We observe that H_(f ) is bounded on H~p(Ω)(1 <p <∞) if f belongs to BMO and we obtain some characterizations for Hf on H^(2)(Ω) of other pseudoconvex domains.In these arguments,Amar's L^(p)-estimations and Berndtsson's L^(2)-estimations for solutions of the ■_(b)-equation play a crucial role.In addition,we solve Gleason's problem for Hardy spaces H^(p)(Ω)(1 ≤p≤∞) of bounded strongly pseudoconvex domains. 展开更多
关键词 Hankel operator Hardy space Bergman space pseudoconvex domain
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SUMS OF DUAL TOEPLITZ PRODUCTS ON THE ORTHOGONAL COMPLEMENTS OF FOCK-SOBOLEV SPACES
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作者 陈泳 Young Joo Lee 《Acta Mathematica Scientia》 SCIE CSCD 2024年第3期810-822,共13页
We consider dual Toeplitz operators on the orthogonal complements of the FockSobolev spaces of all nonnegative real orders.First,for symbols in a certain class containing all bounded functions,we study the problem of ... We consider dual Toeplitz operators on the orthogonal complements of the FockSobolev spaces of all nonnegative real orders.First,for symbols in a certain class containing all bounded functions,we study the problem of when an operator which is finite sums of the dual Toeplitz products is compact or zero.Next,for bounded symbols,we construct a symbol map and exhibit a short exact sequence associated with the C^(*)-algebra generated by all dual Toeplitz operators with bounded symbols. 展开更多
关键词 dual Toeplitz operators Fock-Sobolev spaces symbol map
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Physics package based on intracavity laser cooling ^(87)Rb atoms for space cold atom microwave clock
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作者 邓思敏达 任伟 +9 位作者 项静峰 赵剑波 李琳 张迪 万金银 孟艳玲 蒋小军 李唐 刘亮 吕德胜 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第7期22-26,共5页
This article proposes a new physics package to enhance the frequency stability of the space cold atom clock with the advantages of a microgravity environment. Clock working processes, including atom cooling, atomic st... This article proposes a new physics package to enhance the frequency stability of the space cold atom clock with the advantages of a microgravity environment. Clock working processes, including atom cooling, atomic state preparation,microwave interrogation, and transition probability detection, are integrated into the cylindrical microwave cavity to achieve a high-performance and compact physics package for the space cold atom clock. We present the detailed design and ground-test results of the cold atom clock physics package in this article, which demonstrates a frequency stability of 1.2×10^(-12) τ^(-1/2) with a Ramsey linewidth of 12.5 Hz, and a better performance is predicted with a 1 Hz or a narrower Ramsey linewidth in microgravity environment. The miniaturized cold atom clock based on intracavity cooling has great potential for achieving space high-precision time-frequency reference in the future. 展开更多
关键词 atomic clock MICROGRAVITY microwave cavity space station frequency stability
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Rock Mass Quality Rating Based on the Multi-Criteria Grey Metric Space
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作者 Miloš Gligoric Zoran Gligoric +3 位作者 Saša Jovanovic Suzana Lutovac Dragan Pamucar Ivan Jankovic 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第9期2635-2664,共30页
Assessment of rock mass quality significantly impacts the design and construction of underground and open-pit mines from the point of stability and economy.This study develops the novel Gromov-Hausdorff distance for r... Assessment of rock mass quality significantly impacts the design and construction of underground and open-pit mines from the point of stability and economy.This study develops the novel Gromov-Hausdorff distance for rock quality(GHDQR)methodology for rock mass quality rating based on multi-criteria grey metric space.It usually presents the quality of surrounding rock by classes(metric spaces)with specified properties and adequate interval-grey numbers.Measuring the distance between surrounding rock sample characteristics and existing classes represents the core of this study.The Gromov-Hausdorff distance is an especially useful discriminant function,i.e.,a classifier to calculate these distances,and assess the quality of the surrounding rock.The efficiency of the developed methodology is analyzed using the Mean Absolute Percentage Error(MAPE)technique.Seven existing methods,such as the Gaussian cloud method,Discriminant method,Mutation series method,Artificial neural network(ANN),Support vector machine(SVM),Grey wolf optimizer and Support vector classification method(GWO-SVC)and Rock mass rating method(RMR)are used for comparison with the proposed GHDQR method.The share of the highly accurate category of 85.71%clearly indicates compliance with actual values obtained by the compared methods.The results of comparisons showed that the model enables objective,efficient,and reliable assessment of rock mass quality. 展开更多
关键词 Rock mass rating MULTI-CRITERIA class metric space interval-grey numbers
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Detection accuracy of target accelerations based on vortex electromagnetic wave in keyhole space
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作者 郭凯 雷爽 +2 位作者 雷艺 周红平 郭忠义 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期283-290,共8页
The influence of the longitudinal acceleration and the angular acceleration of detecting target based on vortex electromagnetic waves in keyhole space are analyzed.The spectrum spreads of different orbital angular mom... The influence of the longitudinal acceleration and the angular acceleration of detecting target based on vortex electromagnetic waves in keyhole space are analyzed.The spectrum spreads of different orbital angular momentum(OAM)modes in different non-line-of-sight situations are simulated.The errors of target accelerations in detection are calculated and compared based on the OAM spectra spreading by using two combinations of composite OAM modes in the keyhole space.According to the research,the effects about spectrum spreads of higher OAM modes are more obvious.The error in detection is mainly affected by OAM spectrum spreading,which can be reduced by reasonably using different combinations of OAM modes in different practical situations.The above results provide a reference idea for investigating keyhole effect when vortex electromagnetic wave is used to detect accelerations. 展开更多
关键词 vortex electromagnetic waves detect accelerations keyhole space spectrum spread
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Minimally invasive management of parapharyngeal space tumors:Introducing a decision-making algorithm and radiologic tool
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作者 Manuel Schoch Gunesh Rajan Grzegorz Karwacki 《Laparoscopic, Endoscopic and Robotic Surgery》 2024年第3期97-101,共5页
Objective Traditionally tumors of the parapharyngeal space(PPS)are resected through transcervical approaches.More recent approaches include endoscopic approaches or transoral robotic surgery(TORS)without directions on... Objective Traditionally tumors of the parapharyngeal space(PPS)are resected through transcervical approaches.More recent approaches include endoscopic approaches or transoral robotic surgery(TORS)without directions on when to use which approach.Our objective was to find objective parameters to choose the most suitable approach.Methods It is a retrospective study containing 6 patients from May 2019 to May 2021 with tumors of the PPS treated in the Department of Otolaryngology and Head-Neck Surgery at the Hospital of Lucerne,Switzerland.Results The data was analysed in average 53 months after surgery.Tumor resection was completed with TORS in 3 patients and endoscopically in 3 patients.Mean operation time was 114 min.No major complications occurred.No evidence of tumor was found in magnetic resonance imaging studies postoperatively in all patients.Conclusion We conclude that a resection via TORS or endoscopic technique is safe and effective.Furthermore,we postulate that the further a tumor is located in the upper lateral area of the PPS,an approach via TORS is less possible. 展开更多
关键词 Oto-rhino-laryngology Endoscopic surgery Robotic surgery Parapharyngeal space tumors
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Utilisation of green urban space for food sufficiency and the realisation of the sustainable development goals-UK stakeholders perspective
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作者 Alex Opoku Anna Duff +1 位作者 Moohammed Wasim Yahia Samuel Ekung 《Geography and Sustainability》 CSCD 2024年第1期13-18,共6页
The exponential growth of food demand due to the increasing global population has the potential to seriously threaten the quality and quantity of food supplies due to climate change.This study explores the utilisation... The exponential growth of food demand due to the increasing global population has the potential to seriously threaten the quality and quantity of food supplies due to climate change.This study explores the utilisation of green urban spaces for achieving food self-sufficiency by investigating the extent to which sustainable urban farms could be used to reduce the consumption of imported produce in the UK.It also examines urban farming stakeholders'perspective on how food self-sufficiency can help realise the SDGs especially SDG 2(Zero hunger)and SDG 13(Climate action).The study adopts a mixed method approach through a survey with 115 respondents and semi-structured interviews conducted with 12 respondents from 4 different urban farming stakeholder groups.The findings of this study presented a strong correlation between stakeholders who had concerns about where their food came from and the carbon footprint of imported produce.The research shows that,urban farms will no doubt play a vital role in the future of food security in our cities/communities and that the SDGs could be realised through sustainable urban farms implemented within the relevant planning regulations/policies. 展开更多
关键词 Cities Food sufficiency Green urban space Urban farms SDGS
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我国户外运动研究现状、热点与趋势——基于CNKI和Cite Space可视化分析
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作者 曹奎 张骞 +1 位作者 张宜爽 余文军 《鄂州大学学报》 2024年第3期92-95,共4页
运用CNKI和Cite Space6.2.R2软件,对来源于中国知网数据库(CNKI)所收录有关户外运动主题的283篇核心文献的发文量、作者、机构、期刊来源和关键词进行了可视化分析。结果表明:1)从研究现状看,我国户外运动经历了萌芽阶段、快速增长阶段... 运用CNKI和Cite Space6.2.R2软件,对来源于中国知网数据库(CNKI)所收录有关户外运动主题的283篇核心文献的发文量、作者、机构、期刊来源和关键词进行了可视化分析。结果表明:1)从研究现状看,我国户外运动经历了萌芽阶段、快速增长阶段和稳定增长阶段,作者之间合作不够紧密;2)从研究热点来看,近年来我国户外运动研究主题集中于户外运动产业、户外运动教育和户外运动生态共享这三个方面;3)从研究趋势来看,我国户外运动发展趋势偏向于健康中国、乡村振兴、产业融合、中国式现代化、高质量发展和生态文明建设等方面。 展开更多
关键词 户外运动 CNkI数据库 Cite space6.2.R2可视化分析 文献计量分析
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Thermodynamics of charged AdS black hole surrounded by quintessence in restricted phase space
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作者 Siyu Jian Siying Long +1 位作者 Juhua Chen Yongjiu Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第10期205-212,共8页
We study thermodynamics of charged AdS black hole surrounded by quintessence in a new formalism which is called the restricted phase space thermodynamics.This context is based on Visser’s holographic thermodynamics w... We study thermodynamics of charged AdS black hole surrounded by quintessence in a new formalism which is called the restricted phase space thermodynamics.This context is based on Visser’s holographic thermodynamics with a fixed antide Sitter radius and a variable Newton constant.The conjugate variables,central charge C and the chemical potential m,are introduced as a new pair of thermodynamic variables.We find that the iso-e-charge T-S curve becomes non-monotonic when Q<Q_(c).Correspondingly,the F-T curve exhibits a swallow tail structure.This behavior is considered as a van der Waals-like phase transition.As the value of b related to the energy density of Kiselev’s fluid becomes larger,the critical temperature T_(c)will decrease.Thus,the van derWaals-like phase transition will occur at lower temperature.There is always a non-quilibrium transition from a small unstable black hole to a large stable black hole state in the isocoltage T-S process.There exist a maximum and a Hawking-Page phase transition points in theμ-C plane.As the value of b related to Kiselev’s fluid becomes larger,the Hawking-Page phase transition will occur at lower temperature in the isovoltageμ-T process.For other values of the state parameterω,there also exists van der Waals-like phase transition. 展开更多
关键词 Reissner-Nordstrom qAdS black hole restricted phase space variable Newton constant
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Evolving patterns of agricultural production space in China:A network-based approach
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作者 Shuhui Yang Zhongkai Li +2 位作者 Jianlin Zhou Yancheng Gao Xuefeng Cui 《Geography and Sustainability》 CSCD 2024年第1期121-134,共14页
The agricultural production space,as where and how much each agricultural product grows,plays a vital role in meeting the increasing and diverse food demands.Previous studies on agricultural production patterns have p... The agricultural production space,as where and how much each agricultural product grows,plays a vital role in meeting the increasing and diverse food demands.Previous studies on agricultural production patterns have predominantly centered on individual or specific crop types,using methods such as remote sensing or statistical metrological analysis.In this study,we characterize the agricultural production space(APS)by bipartite network connecting agricultural products and provinces,to reveal the relatedness between diverse agricultural products and the spatiotemporal characteristic of provincial production capabilities in China.The results show that core products are cereal,pork,melon,and pome fruit;meanwhile the milk,grape,and fiber crop show an upward trend in centrality,which is in line with diet structure changes in China over the past decades.The little changes in community components and structures of agricultural products and provinces reveal that agricultural production patterns in China are relatively stable.Additionally,identified provincial communities closely resemble China's agricultural natural zones.Furthermore,the observed growth in production capabilities in North and Northeast China implies their potential focus areas for future agricultural production.Despite the superior production capa-bilities of southern provinces,recent years have witnessed a notable decline,warranting special attentions.The findings provide a comprehensive perspective for understanding the complex relationship of agricultural prod-ucts'relatedness,production capabilities and production patterns,which serve as a reference for the agricultural spatial optimization and agricultural sustainable development. 展开更多
关键词 Agricultural system Complex network Agricultural production space Proximity matrix Production capability
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A guidance strategy for rendezvous and docking to the space station in the Earth-Moon NRHO orbit
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作者 XIE Yongchun CHEN Changqing +1 位作者 LI Xiangyu LI Zhenyu 《中国空间科学技术(中英文)》 CSCD 北大核心 2024年第4期29-39,共11页
With the development of space technology,it is possible to build a space station in Earth-Moon space as a transit for Earth-Moon round-trip and entering in the deep space.Rendezvous and docking is one of the key techn... With the development of space technology,it is possible to build a space station in Earth-Moon space as a transit for Earth-Moon round-trip and entering in the deep space.Rendezvous and docking is one of the key technologies for building an Earth-Moon space station.A guidance strategy for rendezvous and docking from the Earth orbit to the space station in the Earth-Moon NRHO orbit is proposed in this paper,which is suitable for engineering applications.Firstly,the rendezvous and docking process is divided into three sections,i.e.,the large-range orbit transfer section,far-range guidance section,and close-range approaching section.The suitable terminal of large-range orbit transfer is selected according to the eigenvalue of NRHO orbit state transition matrix.The two-impulse guidance method based on the relative motion equation in the three-body problem is adopted for the far-range guidance section.The impulse time and amplitude are solved with the optimization algorithm.The linear constant three-body relative motion equation is proposed for the close-range approaching section,and the rendezvous and docking is completed by a two-stage linear approximation.Finally,a simulation analysis is carried out,and the simulation results show that the adopted dynamics equations and the designed guidance law are effective,and the three flight phases are naturally connected to accomplish the rendezvous and docking mission from the Earth orbit to the space station on the Earth-Moon NRHO. 展开更多
关键词 Earth-Moon space station rendezvous and docking NRHO orbit relative motion guidance strategy
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Relationship Between Individuals’Epidemic Risk Perception Within Living Space and Subjective Well-Being:Empirical Evidence from China after the First Wave of COVID-19
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作者 SONG Jiangyu ZHOU Suhong +1 位作者 KWAN Mei-Po ZHENG Zhong 《Chinese Geographical Science》 SCIE CSCD 2024年第2期369-382,共14页
It is common to observe the epidemic risk perception(ERP)and a decline in subjective well-being(SWB)in the context of public health events,such as Corona Virus Disease 2019(COVID-19).However,there have been few studie... It is common to observe the epidemic risk perception(ERP)and a decline in subjective well-being(SWB)in the context of public health events,such as Corona Virus Disease 2019(COVID-19).However,there have been few studies exploring the impact of individuals’ERP within living space on their SWB,especially from a geographical and daily activity perspective after the resumption of work and other activities following a wave of the pandemic.In this paper,we conducted a study with 789 participants in urban China,measuring their ERP within living space and examining its influence on their SWB using path analysis.The results indicated that individuals’ERP within their living space had a significant negative effect on their SWB.The density of certain types of facilities within their living space,such as bus stops,subway stations,restaurants,fast food shops,convenience shops,hospitals,and public toilets,had a significantly negative impact on their SWB,mediated by their ERP within living space.Additionally,participation in out-of-home work and other activities not only increased individuals’ERP within living space,but also strengthened its negative effect on their SWB. 展开更多
关键词 subjective well-being epidemic risk perception living space the density of facilities out-of-home activities
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On Fuzzy Regularly Closed Filters in Michálek Fuzzy Topological Space
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作者 Puthenpurackal Ratnakumar Neethu Bloomy Joseph 《Advances in Pure Mathematics》 2024年第10期779-784,共6页
C.L. Chang’s introduction of fuzzy topology in 1981 opened up new avenues for parallel theories in topology. However, Chang’s work appears to focus more on the topology of fuzzy sets rather than fuzzy topology itsel... C.L. Chang’s introduction of fuzzy topology in 1981 opened up new avenues for parallel theories in topology. However, Chang’s work appears to focus more on the topology of fuzzy sets rather than fuzzy topology itself. In 1975, Michálek presented a functional definition of ordinary topology and later developed fuzzy topology as a distinct extension of this idea, setting it apart from Chang’s approach. While there has been significant research on Chang’s fuzzy topology, Michálek’s version has not received as much attention. This paper introduces the concept of fuzzy regularly closed filters, or FRCM filters, within Michálek’s fuzzy topological space and explores some properties of FRCM ultrafilters. 展开更多
关键词 TOPOLOGY Fuzzy Topology Michálek’s Fuzzy Topological space Fuzzy Closed Fuzzy Open FILTERS
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Research on the Design of Rural Cultural Tourism Space under the Background of Rural Revitalization: A Case Study of Dujiazhuang Village, Mentougou, Beijing
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作者 SONG Rui SHI Guosheng WU Zhipeng 《Journal of Landscape Research》 2024年第2期38-41,共4页
From the perspective of endogenous development concept,Dujiazhuang Village,Mentougou was taken as an example to explore the development of rural cultural tourism space.The rural tourism resources in the west of Beijin... From the perspective of endogenous development concept,Dujiazhuang Village,Mentougou was taken as an example to explore the development of rural cultural tourism space.The rural tourism resources in the west of Beijing are rich in type and numerous,but the development of cultural tourism is unbalanced and inadequate.Guided by the endogenousconcept and driven by the design of cultural tourism space,rural public space should be as the entry point to integrate the elements of rural resources and create a design that stimulates the endogenous ability of villagers.Culture can promote tourism,and industry can drive the economy to increase income and enhance the villagers'cultural identity. 展开更多
关键词 COUNTRYSIDE Endogenous concept Cultural tourism space
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Heterogeneous information phase space reconstruction and stability prediction of filling body–surrounding rock combination
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作者 Dapeng Chen Shenghua Yin +5 位作者 Weiguo Long Rongfu Yan Yufei Zhang Zepeng Yan Leiming Wang Wei Chen 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第7期1500-1511,共12页
Traditional research believes that the filling body can effectively control stress concentration while ignoring the problems of unknown stability and the complex and changeable stress distribution of the filling body... Traditional research believes that the filling body can effectively control stress concentration while ignoring the problems of unknown stability and the complex and changeable stress distribution of the filling body–surrounding rock combination under high-stress conditions.Current monitoring data processing methods cannot fully consider the complexity of monitoring objects,the diversity of monitoring methods,and the dynamics of monitoring data.To solve this problem,this paper proposes a phase space reconstruction and stability prediction method to process heterogeneous information of backfill–surrounding rock combinations.The three-dimensional monitoring system of a large-area filling body–surrounding rock combination in Longshou Mine was constructed by using drilling stress,multipoint displacement meter,and inclinometer.Varied information,such as the stress and displacement of the filling body–surrounding rock combination,was continuously obtained.Combined with the average mutual information method and the false nearest neighbor point method,the phase space of the heterogeneous information of the filling body–surrounding rock combination was then constructed.In this paper,the distance between the phase point and its nearest point was used as the index evaluation distance to evaluate the stability of the filling body–surrounding rock combination.The evaluated distances(ED)revealed a high sensitivity to the stability of the filling body–surrounding rock combination.The new method was then applied to calculate the time series of historically ED for 12 measuring points located at Longshou Mine.The moments of mutation in these time series were at least 3 months ahead of the roadway return dates.In the ED prediction experiments,the autoregressive integrated moving average model showed a higher prediction accuracy than the deep learning models(long short-term memory and Transformer).Furthermore,the root-mean-square error distribution of the prediction results peaked at 0.26,thus outperforming the no-prediction method in 70%of the cases. 展开更多
关键词 deep mining filling body–surrounding rock combination phase space reconstruction multiple time series stability prediction
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Are James Webb Space Telescope Observations Consistent with Warm Dark Matter?
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作者 Bruce Hoeneisen 《International Journal of Astronomy and Astrophysics》 2024年第1期45-60,共16页
We compare observed with predicted distributions of galaxy stellar masses M<sub>* </sub>and galaxy rest-frame ultra-violet luminosities per unit bandwidth L<sub>UV</sub>, in the redsh... We compare observed with predicted distributions of galaxy stellar masses M<sub>* </sub>and galaxy rest-frame ultra-violet luminosities per unit bandwidth L<sub>UV</sub>, in the redshift range z=2 to 13. The comparison is presented as a function of the comoving warm dark matter free-streaming cut-off wavenumber k<sub>fs</sub>. For this comparison the theory is a minimal extension of the Press-Schechter formalism with only two parameters: the star formation efficiency, and a proportionality factor between the star formation rate per galaxy and LUV</sub>. These two parameters are fixed to their values obtained prior to the James Webb Space Telescope (JWST) data. The purpose of this comparison is to identify if, and where, detailed astrophysical evolution is needed to account for the new JWST observations. 展开更多
关键词 James Webb space Telescope JWST Warm Dark Matter
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Space/Air Covert Communications:Potentials,Scenarios,and Key Technologies
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作者 Mao Haobin Liu Yanming +5 位作者 Zhu Lipeng Mao Tianqi Xiao Zhenyu Zhang Rui Han Zhu Xia Xianggen 《China Communications》 SCIE CSCD 2024年第3期1-18,共18页
Space/air communications have been envisioned as an essential part of the next-generation mobile communication networks for providing highquality global connectivity. However, the inherent broadcasting nature of wirel... Space/air communications have been envisioned as an essential part of the next-generation mobile communication networks for providing highquality global connectivity. However, the inherent broadcasting nature of wireless propagation environment and the broad coverage pose severe threats to the protection of private data. Emerging covert communications provides a promising solution to achieve robust communication security. Aiming at facilitating the practical implementation of covert communications in space/air networks, we present a tutorial overview of its potentials, scenarios, and key technologies. Specifically, first, the commonly used covertness constraint model, covert performance metrics, and potential application scenarios are briefly introduced. Then, several efficient methods that introduce uncertainty into the covert system are thoroughly summarized, followed by several critical enabling technologies, including joint resource allocation and deployment/trajectory design, multi-antenna and beamforming techniques, reconfigurable intelligent surface(RIS), and artificial intelligence algorithms. Finally, we highlight some open issues for future investigation. 展开更多
关键词 artificial intelligence(AI) sixth generation(6G) space-air-ground integrated networks(SAGINs) space/air covert communications
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How the Flat Space Cosmology Model Correlates the Recombination CMB Temperature of 3000 K with a Redshift of 1100
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作者 Eugene Terry Tatum U. V. S. Seshavatharam 《Journal of Modern Physics》 2024年第2期174-178,共5页
This paper shows how the Flat Space Cosmology model correlates the recom-bination epoch CMB temperature of 3000 K with a cosmological redshift of 1100. This proof is given in support of the recent publication that the... This paper shows how the Flat Space Cosmology model correlates the recom-bination epoch CMB temperature of 3000 K with a cosmological redshift of 1100. This proof is given in support of the recent publication that the Tatum and Seshavatharam Hubble temperature formulae can be derived using the Stephan-Boltzmann dispersion law. Thus, as explained herein, the era of high precision Planck scale quantum cosmology has arrived. 展开更多
关键词 Hubble Constant Cosmic Microwave Background Quantum Cosmology Stephan-Boltzmann Upsilon Coupling Constant Flat space Cosmology ΛCDM Cosmology
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THREE KINDS OF DENTABILITIES IN BANACH SPACES AND THEIR APPLICATIONS
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作者 张子厚 周晶 《Acta Mathematica Scientia》 SCIE CSCD 2024年第2期445-454,共10页
In this paper,we study some dentabilities in Banach spaces which are closely related to the famous Radon-Nikodym property.We introduce the concepts of the weak^(*)-weak denting point and the weak^(*)-weak^(*)denting p... In this paper,we study some dentabilities in Banach spaces which are closely related to the famous Radon-Nikodym property.We introduce the concepts of the weak^(*)-weak denting point and the weak^(*)-weak^(*)denting point of a set.These are the generalizations of the weak^(*)denting point of a set in a dual Banach space.By use of the weak^(*)-weak denting point,we characterize the very smooth space,the point of weak^(*)-weak continuity,and the extreme point of a unit ball in a dual Banach space.Meanwhile,we also characterize an approximatively weak compact Chebyshev set in dual Banach spaces.Moreover,we define the nearly weak dentability in Banach spaces,which is a generalization of near dentability.We prove the necessary and sufficient conditions of the reflexivity by nearly weak dentability.We also obtain that nearly weak dentability is equivalent to both the approximatively weak compactness of Banach spaces and the w-strong proximinality of every closed convex subset of Banach spaces. 展开更多
关键词 weak^(*)-weak denting point nearly weak dentability very smooth space point of weak^(*)-weak continuity extreme point approximatively weak compactness w-strong proximinality REFLEXIVITY
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