To address the challenges of insufficient visualization in the industrial robot assembly operation system and the limitation of visualizing only geometric attributes of physical properties,a method is proposed for con...To address the challenges of insufficient visualization in the industrial robot assembly operation system and the limitation of visualizing only geometric attributes of physical properties,a method is proposed for constructing an industrial robot assembly system based on virtual reality technology.Focusing on the shaft hole assembly,the mechanical characteristics of the industrial robot shaft hole assembly process are analyzed and a dynamic model is established for shaft hole assembly operations.The key elements of virtual assembly operations for industrial robots are summarized and a five-dimensional model is proposed for industrial robot virtual operations.Utilizing the Unity3D engine based on the 5-D model for industrial robot virtual operations,an industrial robot shaft hole assembly system is developed.This system enables virtual assembly operations,displays physical attributes,and provides valuable references for the research of virtual systems.展开更多
Porous titanium(Ti)scaffolds have been extensively utilized as bone substitute scaffolds due to their superior biocompatibility and excellent mechanical properties.However,naturally formed TiO2 on the surface limits f...Porous titanium(Ti)scaffolds have been extensively utilized as bone substitute scaffolds due to their superior biocompatibility and excellent mechanical properties.However,naturally formed TiO2 on the surface limits fast osseointegration.Different biomolecules have been widely utilized to overcome this issue;however,homogeneous porous Ti scaffolds could not simultaneously deliver multiple biomolecules that have different release behaviors.In this study,functionally graded porous Ti scaffolds(FGPTs)with dense inner and porous outer parts were fabricated using a two-body combination and densification procedure.FGPTs with growth factor(BMP-2)and antibiotics(TCH)exhibited suitable mechanical properties as bone substituting material and presented good structural stability.The release of BMP-2 was considerably prolonged,whereas the release of TCH was comparable to that of homogenous porous titanium scaffolds(control group).The osteogenic differentiation obtained using FGPTs was maintained due to the prolonged release of BMP-2.The antimicrobial properties of these scaffolds were verified using S.aureus in terms of prior release time.In addition,various candidates for graded porous Ti scaffolds with altered pore characteristics were presented.展开更多
Assembly errors have great influence on assembly quality in robotic assembly systems. Error analysis is directed to the propagations and accumula-tions of various errors and their effect on assembly success.Using the ...Assembly errors have great influence on assembly quality in robotic assembly systems. Error analysis is directed to the propagations and accumula-tions of various errors and their effect on assembly success.Using the screw coordinates, assembly errors are represented as 'error twist', the extremely compact expression. According to the law of screw composition, relative position and orientation errors of mating parts are computed and the necessary condition of assembly success is concluded. A new simple method for measuring assembly errors is also proposed based on the transformation law of a screw.Because of the compact representation of error, the model presented for error analysis can be applied to various part- mating types and especially useful for error analysis of complexity assembly.展开更多
Today＇s production systems are demanded to exhibit an increased flexibility and mutability in order to deal with dynamically changing conditions, objectives and an increasing number of product variants within industr...Today＇s production systems are demanded to exhibit an increased flexibility and mutability in order to deal with dynamically changing conditions, objectives and an increasing number of product variants within industrial turbulent environments. Flexible automated systems are requested in order to improve dynamic production efficiency, e.g. robot-based hardware and PC-based controllers, but these usually induce a significantly higher production complexity, whereby the efforts for planning and programming, but also setups and reconfiguration, expand. In this paper a definition and some concepts of self-optimizing assembly systems are presented to describe possible ways to reduce the planning efforts in complex production systems. The concept of self-optimization in assembly systems will be derived from a theoretical approach and will be transferred to a specific application scenario---the automated assembly of a miniaturized solid state laser--where the challenges of unpredictable influences from e.g. component tolerances can be overcome by the help of self-optimization.展开更多
Product assembly occupies an extremely important position in the whole production process of products. At present, due to the growing demand of consumers for personalized and customized products, the traditional manua...Product assembly occupies an extremely important position in the whole production process of products. At present, due to the growing demand of consumers for personalized and customized products, the traditional manual assembly method is inefficient, and pure automatic assembly is difficult and costly, which is difficult to meet the production needs of enterprises. Therefore, the intelligent assembly system of human-computer integration arises at the historic moment and realizes high-quality and high-efficiency product assembly.展开更多
Presents a multi robot cooperative assembly system (MRCAS) which is composed of an organizer computer, three industrial robots, PUMA 562 mounted on an omni directional vehicle, PUMA 760 and Adept I and organized into ...Presents a multi robot cooperative assembly system (MRCAS) which is composed of an organizer computer, three industrial robots, PUMA 562 mounted on an omni directional vehicle, PUMA 760 and Adept I and organized into a hierarchical structure with the cooperation organization on the top and the coordination motion at the bottom to solve the main problem of coordination and cooperation among robots, and concludes with experimental results that MRCAS is reconfigurable and adaptable as the mission changes.展开更多
The quality and aroma of strong-flavor Baijiu are mainly dependent on Daqu,pit mud(PM),and the interaction of both.However,little is known about how their combination patterns affect the microbiome and metabolome of Z...The quality and aroma of strong-flavor Baijiu are mainly dependent on Daqu,pit mud(PM),and the interaction of both.However,little is known about how their combination patterns affect the microbiome and metabolome of Zaopei,especially the metabolic function of rare taxa.Here,an experiment on industrial size was designed to assess the effects of 6 combinations(3 kinds of Daqu×2 kinds of PM)on the composition and assembly of different taxa,as well as the flavor profile.The results showed that Zaopei's microbiota was composed of a few abundant taxa and enormous rare taxa,and rare bacterial and abundant fungal subcommunities were significantly affected by combination patterns.The assembly processes of abundant/rare taxa and bacterial/fungal communities were distinct,and environmental changes mediated the balance between stochastic and deterministic processes in rare bacteria assembly.Furthermore,specific combination patterns improved the flavor quality of Zaopei by enhancing the interspecies interaction,which was closely related to rare taxa,especially rare bacteria.These findings highlighted that rare bacteria might be the keystone in involving community interaction and maintaining metabolic function,which provided a scientific foundation for better understanding and regulating the brewing microbiota from the viewpoint of microbial ecology.展开更多
In recent years,the rapid development of large-scale satellite constellations has challenged the mass production capabilities of satellite manufacturers.Assembly is the last and critical phase of satellite production....In recent years,the rapid development of large-scale satellite constellations has challenged the mass production capabilities of satellite manufacturers.Assembly is the last and critical phase of satellite production.Achieving satellite mass assembly is the key to realizing satellite mass production.To this end,satellite manufacturers are working to construct the satellite mass assembly shop-floor(SMAS)to enable moving assembly.However,there is still a lack of a modularized manufacturing system oriented to flexible production for SMAS,as well as disturbance detection methods and production-logistics synchronization methods to deal with various disturbances.Therefore,this paper proposes a digital twin-based production-logistics synchronization system(DT-PLSS)for SMAS.The framework of DT-PLSS is introduced first.In this framework,DT-PLSS can achieve modular construction,as well as distributed management and control.Based on the proposed framework,the construction methods of resource level digital twin(DT),workstation level DT,and shop-floor level DT in SMAS are discussed.The DT-based disturbance detection method for SMAS is presented,aiming to detect or predict di erent types of disturbances and to analyze the e ect of disturbances.Then,a DT enhanced production-logistics synchronization mechanism for SMAS is proposed.With this mechanism,the logistics distribution in the dynamic shop-floor environment and production-logistics synchronization under various disturbances can be realized.Finally,a case study in a real SMAS verifies the feasibility and e ectiveness of the proposed system and methods.This research proposes a practical framework and system which could realize disturbance detection,logistics distribution,and the production-logistics synchronization in complex SMAS scenario e ectively.展开更多
Membrane electrode assembly(MEA)is widely considered to be the most promising type of electrolyzer for the practical application of electrochemical CO_(2) reduction reaction(CO_(2)RR).In MEAs,a square-shaped cross-sec...Membrane electrode assembly(MEA)is widely considered to be the most promising type of electrolyzer for the practical application of electrochemical CO_(2) reduction reaction(CO_(2)RR).In MEAs,a square-shaped cross-section in the flow channel is normally adopted,the configuration optimization of which could potentially enhance the performance of the electrolyzer.This paper describes the numerical simulation study on the impact of the flow-channel cross-section shapes in the MEA electrolyzer for CO_(2)RR.The results show that wide flow channels with low heights are beneficial to the CO_(2)RR by providing a uniform flow field of CO_(2),especially at high current densities.Moreover,the larger the electrolyzer,the more significant the effect is.This study provides a theoretical basis for the design of high-performance MEA electrolyzers for CO_(2)RR.展开更多
Juglans sigillata is an economically valuable nut crop renowned for its nutritional richness,including essential nutrients,antioxidants,and healthy fats,which boost human cardial,brain and gut health.Despite its impor...Juglans sigillata is an economically valuable nut crop renowned for its nutritional richness,including essential nutrients,antioxidants,and healthy fats,which boost human cardial,brain and gut health.Despite its importance,the lack of a complete genome assembly has been a stumbling block in its biological breeding process.Therefore,we generated deep coverage ultralong Oxford Nanopore Technology(ONT)and PacBio HiFi reads to construct a telomere-to-telomere(T2T)genome assembly.The final assembly spans 537.27 Mb with no gaps,demonstrating a remarkable completeness of 98.1%.We utilized a combination of transcriptome data and homologous proteins to annotate the genome,identifying 36018 protein-coding genes.Furthermore,we profiled global cytosine DNA methylations using ONT sequencing data.Global methylome analysis revealed high methylation levels in transposable element(TE)-rich chromosomal regions juxtaposed with comparatively lower methylation in gene-rich areas.By integrating a detailed multi-omics data analysis,we obtained valuable insights into the mechanism underlying endopleura coloration.This investigation led to the identification of eight candidate genes(e.g.ANR)involved in anthocyanin biosynthesis pathways,which are crucial for the development of color in plants.The comprehensive genome assembly and the understanding of the genetic basis of important traits like endopleura coloration will open avenues for more efficient breeding programs and improved crop quality.展开更多
A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefo...A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefore,this study aimed to compare the performance outcomes of MEA using electrodes with single and three catalyst layers.This study measured Electrochemical Surface Area(ECSA),Electrochemical Impedance Spectroscopy(EIS),X-ray Diffraction analysis(XRD),and X-ray Fluorescence(XRF).Furthermore,the round-trip efficiency(RTE)of the MEA,as w ell as the performance in FC and WE mode,was measured.In comparison,The ECSA values of Pt-Ru/C and Pt/C with three catalyst layers were higher than the single catalyst layer.This result was supported by electrode characterization data for XRD and XRF.The respective electrical conductivity values of Pt-Ru/C and Pt/C with three catalyst layers are also higher than the single cata-lyst layer,and the performance of URFC using MEA with three catalyst layers has the highest value of RTE among the MEA performances of URFC,which is 100%at a current density of 4 mA·cm-2.展开更多
Soil microbiomes are significant for biodiversity,crucial for ecosystem functions,and vital for the health of various organisms.Nevertheless,the impacts of season and plant species shifts on soil microbial diversity a...Soil microbiomes are significant for biodiversity,crucial for ecosystem functions,and vital for the health of various organisms.Nevertheless,the impacts of season and plant species shifts on soil microbial diversity and community assembly are still poorly understood.This study explored soil bacterial,fungal,and protistan communities during summer and winter in a coastal wetland affected by Spartina alterniflora invasion and subsequent Cyperus malaccensis or Kandelia obovata restoration.The results showed that bacterial,fungal,and protistan diversity were 2.63%,40.3%,and 9.90%higher in winter than in summer,respectively.Plant species had a distinct impact on microbial diversity.Notably,K.obovata restoration significantly increased bacterial diversity,but decreased protistan diversity,with no effect on fungal diversity when compared to S.alterniflora invasion.Season and plant species both significantly influenced the community structure of bacteria,fungi,and protists.However,protistan community structure was more sensitive to season compared to the structure of bacterial and fungal communities.The complexity of co-occurrence networks within or among bacteria,fungi,and protists was higher in winter than in summer.Bacterial and protistan community assembly was primarily driven by stochastic processes,while fungal assembly was dominated by deterministic processes.Bacterial and protistan community assembly exhibited lower stochasticity in winter compared to summer,suggesting a more deterministic assembly of communities during winter.Our findings highlight the critical role of season and plant species in regulating microbial communities,revealing higher microbial diversity,network complexity,and determinism in community assembly during winter compared to summer in a subtropical coastal wetland.展开更多
Molecular recognition of fullerene using various host compounds is well-known in literature.But most studies focus on host-vip complexation in solution using host compounds with a single binding cavity.Herein,we rep...Molecular recognition of fullerene using various host compounds is well-known in literature.But most studies focus on host-vip complexation in solution using host compounds with a single binding cavity.Herein,we report a series of highly preorganized janusarene derivatives with homoditopic binding sites.These novel janusarenes can bind and align various fullerenes such as C_(60),C_(70),C_(84),and Gd@C_(82)in a highly efficient manner.Robust shape complementary association and assembly are observed in solution,in the bulk solid state,in the liquid crystalline state,or on surface,and the assembled structures are characterized by nuclear magnetic resonance(NMR)titration,X-ray diffraction,polarized optical microscopy,and scanning tunneling microscopy.展开更多
Common bean(Phaseolus vulgaris L.)is a vital source of protein and essential nutrients for human consumption and plays a key role in sustainable agriculture due to its nitrogen-fixing ability(Nadeem et al.,2021).Kidne...Common bean(Phaseolus vulgaris L.)is a vital source of protein and essential nutrients for human consumption and plays a key role in sustainable agriculture due to its nitrogen-fixing ability(Nadeem et al.,2021).Kidney beans,a subcategory of dry common beans,are highly valued for their rich protein,dietary fiber,low fat content,and various trace elements(Garcia-Cordero et al.,2021).Despite the release of several de novo genome assemblies(Goodstein et al.,2012;Schmutz et al.,2014;Vlasova et al.,2016;Cortinovis et al.,2024),existing common bean genomes remain incomplete,particularly in complex regions such as centromeres and telomeres,limiting a comprehensive understanding of the genomic landscape.展开更多
Despite the gradual transformation of traditional manufacturing by the Human-Robot Collaboration Assembly(HRCA),challenges remain in the robot’s ability to understand and predict human assembly intentions.This study ...Despite the gradual transformation of traditional manufacturing by the Human-Robot Collaboration Assembly(HRCA),challenges remain in the robot’s ability to understand and predict human assembly intentions.This study aims to enhance the robot’s comprehension and prediction capabilities of operator assembly intentions by capturing and analyzing operator behavior and movements.We propose a video feature extraction method based on the Temporal Shift Module Network(TSM-ResNet50)to extract spatiotemporal features from assembly videos and differentiate various assembly actions using feature differences between video frames.Furthermore,we construct an action recognition and segmentation model based on the Refined-Multi-Scale Temporal Convolutional Network(Refined-MS-TCN)to identify assembly action intervals and accurately acquire action categories.Experiments on our self-built reducer assembly action dataset demonstrate that our network can classify assembly actions frame by frame,achieving an accuracy rate of 83%.Additionally,we develop a HiddenMarkovModel(HMM)integrated with assembly task constraints to predict operator assembly intentions based on the probability transition matrix and assembly task constraints.The experimental results show that our method for predicting operator assembly intentions can achieve an accuracy of 90.6%,which is a 13.3%improvement over the HMM without task constraints.展开更多
Carbon dots(CDs)-based composites have shown impressive performance in fields of information encryption and sensing,however,a great challenge is to simultaneously implement multi-mode luminescence and room-temperature...Carbon dots(CDs)-based composites have shown impressive performance in fields of information encryption and sensing,however,a great challenge is to simultaneously implement multi-mode luminescence and room-temperature phosphorescence(RTP)detection in single system due to the formidable synthesis.Herein,a multifunctional composite of Eu&CDs@p RHO has been designed by co-assembly strategy and prepared via a facile calcination and impregnation treatment.Eu&CDs@p RHO exhibits intense fluorescence(FL)and RTP coming from two individual luminous centers,Eu3+in the free pores and CDs in the interrupted structure of RHO zeolite.Unique four-mode color outputs including pink(Eu^(3+),ex.254 nm),light violet(CDs,ex.365 nm),blue(CDs,254 nm off),and green(CDs,365 nm off)could be realized,on the basis of it,a preliminary application of advanced information encoding has been demonstrated.Given the free pores of matrix and stable RTP in water of confined CDs,a visual RTP detection of Fe^(3+)ions is achieved with the detection limit as low as 9.8μmol/L.This work has opened up a new perspective for the strategic amalgamation of luminous vips with porous zeolite to construct the advanced functional materials.展开更多
phoD and pqqC gene occurrence in bacteria allows them to mobilize phosphorus(P)by mineralizing organic P(Po)and solubilizing inorganic P(Pi),respectively.Community characteristics of phoD-and pqqC-harboring bacteria(p...phoD and pqqC gene occurrence in bacteria allows them to mobilize phosphorus(P)by mineralizing organic P(Po)and solubilizing inorganic P(Pi),respectively.Community characteristics of phoD-and pqqC-harboring bacteria(phoD-and pqqC-HB,respectively)mediate P cycling.However,whether the microbial community assembly and keystone taxa of phoD-and pqqC-HB regulate P availability and distinct regulatory pathways between these two genes remain unclear.In this study,soil microbial community characteristics and P availability were investigated in four long-term(38-year)fertilization regimes:control with no fertilizer(CK),P fertilizer(PF),nitrogen(N)and P fertilizers(NP),and N fertilizer,P fertilizer,and manure(NPM).The N addition treatments(NP and NPM)significantly changed the community composition and increased the abundances of phoD-and pqqC-HB compared to the no-N addition treatments(CK and PF).Stochastic processes dominated the community assembly of both phoD-and pqqC-HB,and the relative contributions of stochasticity increased with N addition.Furthermore,the N addition treatments resulted in greater network complexity and higher abundances of keystone taxa of phoD-and pqqC-HB compared to those of the no-N addition treatments.The keystone taxa implicated in P cycling were also associated with carbon(C)and N cycling processes.Microbial community composition and assembly processes were the main factors driving labile Pi for phoD-HB,whereas keystone taxa contributed the most to labile Pi for pqqC-HB.These results emphasize that distinct mechanisms of phoD-and pqqC-HB regulate P availability under fertilization management and underline the significance of microbial community assembly and keystone taxa in soil ecological functions,offering fresh perspectives on comprehending the biological processes facilitated by microorganisms in enhancing soil quality.展开更多
A renewable fluorescent material(GСCP5L)has been constructed via supramolecular assembly between a new derivative of pillararene,namely leggero pillar[5]arene,as the host molecule(CP5L)and a tetraphenylethylene(TPE)-...A renewable fluorescent material(GСCP5L)has been constructed via supramolecular assembly between a new derivative of pillararene,namely leggero pillar[5]arene,as the host molecule(CP5L)and a tetraphenylethylene(TPE)-based ditopic vip(G).This new material can simultaneously perform efficient detection and separation of silver(I)from aqueous environments.Possessing an electron-rich cavity and two cytosine groups modified on both rims,CP5L functions as the host-vip binding site for G and offers exclusive coordination sites for further interaction with Ag+.Adding Ag+to the system undergoes dramatic fluorescence enhancement due to the mechanism of supramolecular assembly-induced enhanced emission(SAIEE).This fluorescence enhancement allows for efficient and visualized detection following a“light-up”pattern,achieving a limit of detection(LOD)of 1.3×10^(-7)mol/L,which is fully in line with the World Health Organization's drinking water standard of 9×10^(-7)mol/L.In addition,GСCP5L also shows strong anti-interference capability against other cationic species.For the separation of Ag+from aqueous systems,GСCP5L displays exceptional adsorption efficiency(97%)and reliable recovery performance,demonstrating excellent recyclability after five experimental cycles without compromising its adsorption activity.展开更多
Bacterial communities play a crucial role in permafrost biogeochemical cycling and ecosystem function maintenance.Bacterial interaction is one of the main factors in shaping soil bacterial communities.However,how woul...Bacterial communities play a crucial role in permafrost biogeochemical cycling and ecosystem function maintenance.Bacterial interaction is one of the main factors in shaping soil bacterial communities.However,how would bacterial interaction influence the bacterial communities in permafrost of the Qinghai-Tibet Plateau(QTP)remains largely unknown.Here we collected paired soil samples from both the active and permafrost layers of two typical QTP permafrost regions in October 2020 for Tuotuohe River(TTH)and May 2022 for Aerjin(ARJ),and investigated the bacterial communities and the role of interactions in structuring the bacterial community and its assembly process through amplicon sequencing of the 16S rRNA gene.Our study revealed distinct bacterial communities,with significant differences in the relative abundances of Proteobacteria(P<0.05),Acidobacteriota(P<0.001),Bacteroidota(P<0.05),and Planctomycetota(P<0.001)between the active layer and the permafrost layer.More importantly,we found that interspecies interactions,including both positive and negative associations,were strongly correlated with bacterial alpha-diversity and played a significant role in community variation and assembly process.Our findings also showed that the community assembly in both the active and permafrost layers was primarily driven by homogeneous selection of deterministic processes,with interspecies interactions accounting for more than 58%and 63%of all assembly mechanisms,respectively.This is the first study to quantify the contribution of bacterial interactions in shaping the bacterial community and its assembly process in permafrost of QTP,highlighting the importance of considering interspecies interactions in future modeling efforts.Our work also emphasizes the necessity of including interspecies interactions in microbial process projections to reduce uncertainty.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.52005003)the Science and Technology Planning Project of Wuhu City(Grant No.2022jc41)。
文摘To address the challenges of insufficient visualization in the industrial robot assembly operation system and the limitation of visualizing only geometric attributes of physical properties,a method is proposed for constructing an industrial robot assembly system based on virtual reality technology.Focusing on the shaft hole assembly,the mechanical characteristics of the industrial robot shaft hole assembly process are analyzed and a dynamic model is established for shaft hole assembly operations.The key elements of virtual assembly operations for industrial robots are summarized and a five-dimensional model is proposed for industrial robot virtual operations.Utilizing the Unity3D engine based on the 5-D model for industrial robot virtual operations,an industrial robot shaft hole assembly system is developed.This system enables virtual assembly operations,displays physical attributes,and provides valuable references for the research of virtual systems.
基金supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT)(Nos. 2021R1I1A1A01043176 and2021R1A2C1091301)the framework of international cooperation program managed by the National Research Foundation of Korea (No.2021K2A9A2A06037540)+3 种基金Korean Fund for Regenerative Medicine funded by Ministry of Science and ICTMinistry of Health and Welfare (No. 2021M3E5E5096420, Republic of Korea)Korea Medical Device Development Fund grant funded by the Korea government(the Ministry of Science and ICT, the Ministry of Trade, Industry and Energy, the Ministry of Health&Welfare, Republic of Korea, the Ministry of Food and Drug Safety)(Project Number:202011B29)the GRRC program of the Gyeo nggi Province (Grant Number GRRC-KPU2021-A01, Multi-material Machining Innovative Technology Research Center)
文摘Porous titanium(Ti)scaffolds have been extensively utilized as bone substitute scaffolds due to their superior biocompatibility and excellent mechanical properties.However,naturally formed TiO2 on the surface limits fast osseointegration.Different biomolecules have been widely utilized to overcome this issue;however,homogeneous porous Ti scaffolds could not simultaneously deliver multiple biomolecules that have different release behaviors.In this study,functionally graded porous Ti scaffolds(FGPTs)with dense inner and porous outer parts were fabricated using a two-body combination and densification procedure.FGPTs with growth factor(BMP-2)and antibiotics(TCH)exhibited suitable mechanical properties as bone substituting material and presented good structural stability.The release of BMP-2 was considerably prolonged,whereas the release of TCH was comparable to that of homogenous porous titanium scaffolds(control group).The osteogenic differentiation obtained using FGPTs was maintained due to the prolonged release of BMP-2.The antimicrobial properties of these scaffolds were verified using S.aureus in terms of prior release time.In addition,various candidates for graded porous Ti scaffolds with altered pore characteristics were presented.
基金This work is Supported by the National Science Foundation under Grant 863 -512 -9820-04.
文摘Assembly errors have great influence on assembly quality in robotic assembly systems. Error analysis is directed to the propagations and accumula-tions of various errors and their effect on assembly success.Using the screw coordinates, assembly errors are represented as 'error twist', the extremely compact expression. According to the law of screw composition, relative position and orientation errors of mating parts are computed and the necessary condition of assembly success is concluded. A new simple method for measuring assembly errors is also proposed based on the transformation law of a screw.Because of the compact representation of error, the model presented for error analysis can be applied to various part- mating types and especially useful for error analysis of complexity assembly.
文摘Today＇s production systems are demanded to exhibit an increased flexibility and mutability in order to deal with dynamically changing conditions, objectives and an increasing number of product variants within industrial turbulent environments. Flexible automated systems are requested in order to improve dynamic production efficiency, e.g. robot-based hardware and PC-based controllers, but these usually induce a significantly higher production complexity, whereby the efforts for planning and programming, but also setups and reconfiguration, expand. In this paper a definition and some concepts of self-optimizing assembly systems are presented to describe possible ways to reduce the planning efforts in complex production systems. The concept of self-optimization in assembly systems will be derived from a theoretical approach and will be transferred to a specific application scenario---the automated assembly of a miniaturized solid state laser--where the challenges of unpredictable influences from e.g. component tolerances can be overcome by the help of self-optimization.
文摘Product assembly occupies an extremely important position in the whole production process of products. At present, due to the growing demand of consumers for personalized and customized products, the traditional manual assembly method is inefficient, and pure automatic assembly is difficult and costly, which is difficult to meet the production needs of enterprises. Therefore, the intelligent assembly system of human-computer integration arises at the historic moment and realizes high-quality and high-efficiency product assembly.
文摘Presents a multi robot cooperative assembly system (MRCAS) which is composed of an organizer computer, three industrial robots, PUMA 562 mounted on an omni directional vehicle, PUMA 760 and Adept I and organized into a hierarchical structure with the cooperation organization on the top and the coordination motion at the bottom to solve the main problem of coordination and cooperation among robots, and concludes with experimental results that MRCAS is reconfigurable and adaptable as the mission changes.
基金supported by the Cooperation Project of Luzhou Laojiao Co.,Ltd.Sichuan University (21H0997)。
文摘The quality and aroma of strong-flavor Baijiu are mainly dependent on Daqu,pit mud(PM),and the interaction of both.However,little is known about how their combination patterns affect the microbiome and metabolome of Zaopei,especially the metabolic function of rare taxa.Here,an experiment on industrial size was designed to assess the effects of 6 combinations(3 kinds of Daqu×2 kinds of PM)on the composition and assembly of different taxa,as well as the flavor profile.The results showed that Zaopei's microbiota was composed of a few abundant taxa and enormous rare taxa,and rare bacterial and abundant fungal subcommunities were significantly affected by combination patterns.The assembly processes of abundant/rare taxa and bacterial/fungal communities were distinct,and environmental changes mediated the balance between stochastic and deterministic processes in rare bacteria assembly.Furthermore,specific combination patterns improved the flavor quality of Zaopei by enhancing the interspecies interaction,which was closely related to rare taxa,especially rare bacteria.These findings highlighted that rare bacteria might be the keystone in involving community interaction and maintaining metabolic function,which provided a scientific foundation for better understanding and regulating the brewing microbiota from the viewpoint of microbial ecology.
基金Supported by National Natural Science Foundation of China(Grant Nos.52275471,52120105008)New Cornerstone Science Foundation through the Xplorer Prize。
文摘In recent years,the rapid development of large-scale satellite constellations has challenged the mass production capabilities of satellite manufacturers.Assembly is the last and critical phase of satellite production.Achieving satellite mass assembly is the key to realizing satellite mass production.To this end,satellite manufacturers are working to construct the satellite mass assembly shop-floor(SMAS)to enable moving assembly.However,there is still a lack of a modularized manufacturing system oriented to flexible production for SMAS,as well as disturbance detection methods and production-logistics synchronization methods to deal with various disturbances.Therefore,this paper proposes a digital twin-based production-logistics synchronization system(DT-PLSS)for SMAS.The framework of DT-PLSS is introduced first.In this framework,DT-PLSS can achieve modular construction,as well as distributed management and control.Based on the proposed framework,the construction methods of resource level digital twin(DT),workstation level DT,and shop-floor level DT in SMAS are discussed.The DT-based disturbance detection method for SMAS is presented,aiming to detect or predict di erent types of disturbances and to analyze the e ect of disturbances.Then,a DT enhanced production-logistics synchronization mechanism for SMAS is proposed.With this mechanism,the logistics distribution in the dynamic shop-floor environment and production-logistics synchronization under various disturbances can be realized.Finally,a case study in a real SMAS verifies the feasibility and e ectiveness of the proposed system and methods.This research proposes a practical framework and system which could realize disturbance detection,logistics distribution,and the production-logistics synchronization in complex SMAS scenario e ectively.
基金the National Key R&D Program of China(No.2021YFA1501503)the National Natural Science Foundation of China(Nos.22250008,22121004,22108197)+3 种基金the Haihe Laboratory of Sustainable Chemical Transformations(No.CYZC202107)the Natural Science Foundation of Tianjin City(No.21JCZXJC00060)the Program of Introducing Talents of Discipline to Universities(No.BP0618007)the Xplorer Prize for financial support。
文摘Membrane electrode assembly(MEA)is widely considered to be the most promising type of electrolyzer for the practical application of electrochemical CO_(2) reduction reaction(CO_(2)RR).In MEAs,a square-shaped cross-section in the flow channel is normally adopted,the configuration optimization of which could potentially enhance the performance of the electrolyzer.This paper describes the numerical simulation study on the impact of the flow-channel cross-section shapes in the MEA electrolyzer for CO_(2)RR.The results show that wide flow channels with low heights are beneficial to the CO_(2)RR by providing a uniform flow field of CO_(2),especially at high current densities.Moreover,the larger the electrolyzer,the more significant the effect is.This study provides a theoretical basis for the design of high-performance MEA electrolyzers for CO_(2)RR.
基金supported by the Yunnan Seed Laboratory,China(202205AR070001-15)the National Natural Science Foundation of China,China(Grant No.32160697)。
文摘Juglans sigillata is an economically valuable nut crop renowned for its nutritional richness,including essential nutrients,antioxidants,and healthy fats,which boost human cardial,brain and gut health.Despite its importance,the lack of a complete genome assembly has been a stumbling block in its biological breeding process.Therefore,we generated deep coverage ultralong Oxford Nanopore Technology(ONT)and PacBio HiFi reads to construct a telomere-to-telomere(T2T)genome assembly.The final assembly spans 537.27 Mb with no gaps,demonstrating a remarkable completeness of 98.1%.We utilized a combination of transcriptome data and homologous proteins to annotate the genome,identifying 36018 protein-coding genes.Furthermore,we profiled global cytosine DNA methylations using ONT sequencing data.Global methylome analysis revealed high methylation levels in transposable element(TE)-rich chromosomal regions juxtaposed with comparatively lower methylation in gene-rich areas.By integrating a detailed multi-omics data analysis,we obtained valuable insights into the mechanism underlying endopleura coloration.This investigation led to the identification of eight candidate genes(e.g.ANR)involved in anthocyanin biosynthesis pathways,which are crucial for the development of color in plants.The comprehensive genome assembly and the understanding of the genetic basis of important traits like endopleura coloration will open avenues for more efficient breeding programs and improved crop quality.
基金support from the Ministry of Higher Education Malaysia under grant HICOE-2023-005.
文摘A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefore,this study aimed to compare the performance outcomes of MEA using electrodes with single and three catalyst layers.This study measured Electrochemical Surface Area(ECSA),Electrochemical Impedance Spectroscopy(EIS),X-ray Diffraction analysis(XRD),and X-ray Fluorescence(XRF).Furthermore,the round-trip efficiency(RTE)of the MEA,as w ell as the performance in FC and WE mode,was measured.In comparison,The ECSA values of Pt-Ru/C and Pt/C with three catalyst layers were higher than the single catalyst layer.This result was supported by electrode characterization data for XRD and XRF.The respective electrical conductivity values of Pt-Ru/C and Pt/C with three catalyst layers are also higher than the single cata-lyst layer,and the performance of URFC using MEA with three catalyst layers has the highest value of RTE among the MEA performances of URFC,which is 100%at a current density of 4 mA·cm-2.
基金supported by the Natural Resources Science and Technology Innovation Project of Fujian Province,China(No.KY-090000-04-2022-012)the National Natural Science Foundation of China(Nos.42077041 and 42377301)+1 种基金the National Natural Science Foundation of Fujian Province,China(No.2021J011038)the Talent Introduction Program of Minjiang University,China(No.MJY20012).
文摘Soil microbiomes are significant for biodiversity,crucial for ecosystem functions,and vital for the health of various organisms.Nevertheless,the impacts of season and plant species shifts on soil microbial diversity and community assembly are still poorly understood.This study explored soil bacterial,fungal,and protistan communities during summer and winter in a coastal wetland affected by Spartina alterniflora invasion and subsequent Cyperus malaccensis or Kandelia obovata restoration.The results showed that bacterial,fungal,and protistan diversity were 2.63%,40.3%,and 9.90%higher in winter than in summer,respectively.Plant species had a distinct impact on microbial diversity.Notably,K.obovata restoration significantly increased bacterial diversity,but decreased protistan diversity,with no effect on fungal diversity when compared to S.alterniflora invasion.Season and plant species both significantly influenced the community structure of bacteria,fungi,and protists.However,protistan community structure was more sensitive to season compared to the structure of bacterial and fungal communities.The complexity of co-occurrence networks within or among bacteria,fungi,and protists was higher in winter than in summer.Bacterial and protistan community assembly was primarily driven by stochastic processes,while fungal assembly was dominated by deterministic processes.Bacterial and protistan community assembly exhibited lower stochasticity in winter compared to summer,suggesting a more deterministic assembly of communities during winter.Our findings highlight the critical role of season and plant species in regulating microbial communities,revealing higher microbial diversity,network complexity,and determinism in community assembly during winter compared to summer in a subtropical coastal wetland.
基金supported by the National Natural Science Foundation of China(Nos.22325111,2220312,21871298,91956118)Guangdong Basic Research Center of Excellence for Functional Molecular Engineeringthe Sun Yat-sen University。
文摘Molecular recognition of fullerene using various host compounds is well-known in literature.But most studies focus on host-vip complexation in solution using host compounds with a single binding cavity.Herein,we report a series of highly preorganized janusarene derivatives with homoditopic binding sites.These novel janusarenes can bind and align various fullerenes such as C_(60),C_(70),C_(84),and Gd@C_(82)in a highly efficient manner.Robust shape complementary association and assembly are observed in solution,in the bulk solid state,in the liquid crystalline state,or on surface,and the assembled structures are characterized by nuclear magnetic resonance(NMR)titration,X-ray diffraction,polarized optical microscopy,and scanning tunneling microscopy.
基金supported by the National Natural Science Foundation of China(32241045,32241046,32241038)the Major Special Science and Technology Projects in Shanxi Province(202101140601027)+3 种基金Shanxi Provincial Agricultural Key Technologies Breakthrough Project(NYGG01)Doctoral Research Starting Project at Shanxi Agricultural University(2024BQ77)the National Key Research and Development Program of China(2023YFD1202705/2023YFD120270503,2023YFD1202703/2023YFD1202703-4)Shanxi HouJi Laboratory Self-proposed Research Project(202304010930003/202304010930003-03).
文摘Common bean(Phaseolus vulgaris L.)is a vital source of protein and essential nutrients for human consumption and plays a key role in sustainable agriculture due to its nitrogen-fixing ability(Nadeem et al.,2021).Kidney beans,a subcategory of dry common beans,are highly valued for their rich protein,dietary fiber,low fat content,and various trace elements(Garcia-Cordero et al.,2021).Despite the release of several de novo genome assemblies(Goodstein et al.,2012;Schmutz et al.,2014;Vlasova et al.,2016;Cortinovis et al.,2024),existing common bean genomes remain incomplete,particularly in complex regions such as centromeres and telomeres,limiting a comprehensive understanding of the genomic landscape.
文摘Despite the gradual transformation of traditional manufacturing by the Human-Robot Collaboration Assembly(HRCA),challenges remain in the robot’s ability to understand and predict human assembly intentions.This study aims to enhance the robot’s comprehension and prediction capabilities of operator assembly intentions by capturing and analyzing operator behavior and movements.We propose a video feature extraction method based on the Temporal Shift Module Network(TSM-ResNet50)to extract spatiotemporal features from assembly videos and differentiate various assembly actions using feature differences between video frames.Furthermore,we construct an action recognition and segmentation model based on the Refined-Multi-Scale Temporal Convolutional Network(Refined-MS-TCN)to identify assembly action intervals and accurately acquire action categories.Experiments on our self-built reducer assembly action dataset demonstrate that our network can classify assembly actions frame by frame,achieving an accuracy rate of 83%.Additionally,we develop a HiddenMarkovModel(HMM)integrated with assembly task constraints to predict operator assembly intentions based on the probability transition matrix and assembly task constraints.The experimental results show that our method for predicting operator assembly intentions can achieve an accuracy of 90.6%,which is a 13.3%improvement over the HMM without task constraints.
基金supported by the National Natural Science Foundation of China(No.22288101)the 111 Project(No.B17020)。
文摘Carbon dots(CDs)-based composites have shown impressive performance in fields of information encryption and sensing,however,a great challenge is to simultaneously implement multi-mode luminescence and room-temperature phosphorescence(RTP)detection in single system due to the formidable synthesis.Herein,a multifunctional composite of Eu&CDs@p RHO has been designed by co-assembly strategy and prepared via a facile calcination and impregnation treatment.Eu&CDs@p RHO exhibits intense fluorescence(FL)and RTP coming from two individual luminous centers,Eu3+in the free pores and CDs in the interrupted structure of RHO zeolite.Unique four-mode color outputs including pink(Eu^(3+),ex.254 nm),light violet(CDs,ex.365 nm),blue(CDs,254 nm off),and green(CDs,365 nm off)could be realized,on the basis of it,a preliminary application of advanced information encoding has been demonstrated.Given the free pores of matrix and stable RTP in water of confined CDs,a visual RTP detection of Fe^(3+)ions is achieved with the detection limit as low as 9.8μmol/L.This work has opened up a new perspective for the strategic amalgamation of luminous vips with porous zeolite to construct the advanced functional materials.
基金supported by the National Key Research and Development Program of China(No.2022YFD 1901601)the National Natural Science Foundation of China(No.42107360)the Fundamental Research Funds for the Central Universities,China(No.2452021032).
文摘phoD and pqqC gene occurrence in bacteria allows them to mobilize phosphorus(P)by mineralizing organic P(Po)and solubilizing inorganic P(Pi),respectively.Community characteristics of phoD-and pqqC-harboring bacteria(phoD-and pqqC-HB,respectively)mediate P cycling.However,whether the microbial community assembly and keystone taxa of phoD-and pqqC-HB regulate P availability and distinct regulatory pathways between these two genes remain unclear.In this study,soil microbial community characteristics and P availability were investigated in four long-term(38-year)fertilization regimes:control with no fertilizer(CK),P fertilizer(PF),nitrogen(N)and P fertilizers(NP),and N fertilizer,P fertilizer,and manure(NPM).The N addition treatments(NP and NPM)significantly changed the community composition and increased the abundances of phoD-and pqqC-HB compared to the no-N addition treatments(CK and PF).Stochastic processes dominated the community assembly of both phoD-and pqqC-HB,and the relative contributions of stochasticity increased with N addition.Furthermore,the N addition treatments resulted in greater network complexity and higher abundances of keystone taxa of phoD-and pqqC-HB compared to those of the no-N addition treatments.The keystone taxa implicated in P cycling were also associated with carbon(C)and N cycling processes.Microbial community composition and assembly processes were the main factors driving labile Pi for phoD-HB,whereas keystone taxa contributed the most to labile Pi for pqqC-HB.These results emphasize that distinct mechanisms of phoD-and pqqC-HB regulate P availability under fertilization management and underline the significance of microbial community assembly and keystone taxa in soil ecological functions,offering fresh perspectives on comprehending the biological processes facilitated by microorganisms in enhancing soil quality.
基金the Natural Science Foundation of Jilin Province(No.20230101052JC)the National Natural Science Foundation of China(No.52173200)Hangzhou Jingshi Technology Co.,Ltd.,and Hangzhou Xuhui Technology Co.,Ltd.for financial support。
文摘A renewable fluorescent material(GСCP5L)has been constructed via supramolecular assembly between a new derivative of pillararene,namely leggero pillar[5]arene,as the host molecule(CP5L)and a tetraphenylethylene(TPE)-based ditopic vip(G).This new material can simultaneously perform efficient detection and separation of silver(I)from aqueous environments.Possessing an electron-rich cavity and two cytosine groups modified on both rims,CP5L functions as the host-vip binding site for G and offers exclusive coordination sites for further interaction with Ag+.Adding Ag+to the system undergoes dramatic fluorescence enhancement due to the mechanism of supramolecular assembly-induced enhanced emission(SAIEE).This fluorescence enhancement allows for efficient and visualized detection following a“light-up”pattern,achieving a limit of detection(LOD)of 1.3×10^(-7)mol/L,which is fully in line with the World Health Organization's drinking water standard of 9×10^(-7)mol/L.In addition,GСCP5L also shows strong anti-interference capability against other cationic species.For the separation of Ag+from aqueous systems,GСCP5L displays exceptional adsorption efficiency(97%)and reliable recovery performance,demonstrating excellent recyclability after five experimental cycles without compromising its adsorption activity.
基金supported by grants from the National Natural Science Foundation of China for Excellent Young Scientists Fund Program(No.42222105)the National Natural Science Foundation of China General Program(No.42171144)+1 种基金the Assessment of Ecosystem Carbon Stock and Turnover Patterns in Qinghai Province(No.2021-SFA7-1-1)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2021QZKK0100)。
文摘Bacterial communities play a crucial role in permafrost biogeochemical cycling and ecosystem function maintenance.Bacterial interaction is one of the main factors in shaping soil bacterial communities.However,how would bacterial interaction influence the bacterial communities in permafrost of the Qinghai-Tibet Plateau(QTP)remains largely unknown.Here we collected paired soil samples from both the active and permafrost layers of two typical QTP permafrost regions in October 2020 for Tuotuohe River(TTH)and May 2022 for Aerjin(ARJ),and investigated the bacterial communities and the role of interactions in structuring the bacterial community and its assembly process through amplicon sequencing of the 16S rRNA gene.Our study revealed distinct bacterial communities,with significant differences in the relative abundances of Proteobacteria(P<0.05),Acidobacteriota(P<0.001),Bacteroidota(P<0.05),and Planctomycetota(P<0.001)between the active layer and the permafrost layer.More importantly,we found that interspecies interactions,including both positive and negative associations,were strongly correlated with bacterial alpha-diversity and played a significant role in community variation and assembly process.Our findings also showed that the community assembly in both the active and permafrost layers was primarily driven by homogeneous selection of deterministic processes,with interspecies interactions accounting for more than 58%and 63%of all assembly mechanisms,respectively.This is the first study to quantify the contribution of bacterial interactions in shaping the bacterial community and its assembly process in permafrost of QTP,highlighting the importance of considering interspecies interactions in future modeling efforts.Our work also emphasizes the necessity of including interspecies interactions in microbial process projections to reduce uncertainty.
