Affinity propagation(AP)is a classic clustering algorithm.To improve the classical AP algorithms,we propose a clustering algorithm namely,adaptive spectral affinity propagation(AdaSAP).In particular,we discuss why AP ...Affinity propagation(AP)is a classic clustering algorithm.To improve the classical AP algorithms,we propose a clustering algorithm namely,adaptive spectral affinity propagation(AdaSAP).In particular,we discuss why AP is not suitable for non-spherical clusters and present a unifying view of nine famous arbitrary-shaped clustering algorithms.We propose a strategy of extending AP in non-spherical clustering by constructing category similarity of objects.Leveraging the monotonicity that the clusters’number increases with the self-similarity in AP,we propose a model selection procedure that can determine the number of clusters adaptively.For the parameters introduced by extending AP in non-spherical clustering,we provide a grid-evolving strategy to optimize them automatically.The effectiveness of AdaSAP is evaluated by experiments on both synthetic datasets and real-world clustering tasks.Experimental results validate that the superiority of AdaSAP over benchmark algorithms like the classical AP and spectral clustering algorithms.展开更多
Leaves of a Metasequoia glyptostroboides tree in Paomu Village,Longshan County,Hunan Province (Paomu Tree) possess"Even Type"cuticles and frill-margined stomata similar to those of fossil Metasequoia by far ...Leaves of a Metasequoia glyptostroboides tree in Paomu Village,Longshan County,Hunan Province (Paomu Tree) possess"Even Type"cuticles and frill-margined stomata similar to those of fossil Metasequoia by far known but different from all other living Metasequoia trees(common trees).Paomu Tree is thus hypothesized as the real"living fossil",which has been supported by preliminary DNA analyses. Techniques of clearing leaf,epidermis stripping,展开更多
In this paper a negative electron affinity （NEA） multialkali photocathode of （Na<sub>2</sub>KSb-Cs）-O-Cs structure is fabricated by new technology. It is found that its emission stability is much bette...In this paper a negative electron affinity （NEA） multialkali photocathode of （Na<sub>2</sub>KSb-Cs）-O-Cs structure is fabricated by new technology. It is found that its emission stability is much better than that of the NEA GaAs photocathode, but is inferior to that of the conventional Na<sub>2</sub>KSb（Cs）. After 70 hour performance in a pumping vacuum system, the emission sensitivity of the NEA （Na<sub>2</sub>KSb-Cs）-O-Cs photocathode drops only by 2.5%. The emission stability is closely related to the states of the activation cesium and oxygen during activation, best results being obtained with cesium ions and excited oxygen. Furthermore, better photoemission sensitivity and emission stability may be obtained if the cathode is illuminated by intense white light during the activation process. The performance of the NEA （Na<sub>2</sub>KSb-Cs）-O-Cs cathode which has not been illuminated by intense white light during activation may be improved by the illumination even during operation intermission.展开更多
Integrins are heterodimers that mediate cell adhesion and transduce signals bidirectionally across the cell membrane.Integrins often exist in low affinity(or inactive) states for
[Objective]Crop line extraction is critical for improving the efficiency of autonomous agricultural machines in the field.However,traditional detection methods struggle to maintain high accuracy and efficiency under c...[Objective]Crop line extraction is critical for improving the efficiency of autonomous agricultural machines in the field.However,traditional detection methods struggle to maintain high accuracy and efficiency under challenging conditions,such as strong light exposure and weed interference.The aims are to develop an effective crop line extraction method by combining YOLOv8-G,Affinity Propagation,and the Least Squares method to enhance detection accuracy and performance in complex field environments.[Methods]The proposed method employs machine vision techniques to address common field challenges.YOLOv8-G,an improved object detection algorithm that combines YOLOv8 and Ghost‐NetV2 for lightweight,high-speed performance,was used to detect the central points of crops.These points were then clustered using the Affinity Propagation algorithm,followed by the application of the Least Squares method to extract the crop lines.Comparative tests were conducted to evaluate multiple backbone networks within the YOLOv8 framework,and ablation studies were performed to validate the enhancements made in YOLOv8-G.[Results and Discussions]The performance of the proposed method was compared with classical object detection and clustering algorithms.The YOLOv8-G algorithm achieved average precision(AP)values of 98.22%,98.15%,and 97.32%for corn detection at 7,14,and 21 days after emergence,respectively.Additionally,the crop line extraction accuracy across all stages was 96.52%.These results demonstrate the model's ability to maintain high detection accuracy despite challenging conditions in the field.[Conclusions]The proposed crop line extraction method effectively addresses field challenges such as lighting and weed interference,enabling rapid and accurate crop identification.This approach supports the automatic navigation of agricultural machinery,offering significant improvements in the precision and efficiency of field operations.展开更多
The addition of electrons to form gas-phase multiply charged anions(MCAs)normally requires sophisticated experiments or calculations.In this work,the factors stabilizing the MCAs,the maximum electron uptake of gas-pha...The addition of electrons to form gas-phase multiply charged anions(MCAs)normally requires sophisticated experiments or calculations.In this work,the factors stabilizing the MCAs,the maximum electron uptake of gas-phase molecules,X,and the electronic stability of MCAs X^(Q-),are discussed.The drawbacks encountered when applying computational and/or conceptual density functional theory(DFT)to MCAs are highlighted.We develop and test a different model based on the valence-state concept.As in DFT,the electronic energy,E(N,v_(ex)),is a continuous function of the average electron number,N,and the external potential,v_(ex),of the nuclei.The valence-state-parabola is a second-order polynomial that allows extending E(N,v_(ex))to dianions and higher MCAs.The model expresses the maximum electron acceptance,Q_(max),and the higher electron affinities,A_Q,as simple functions of the firstelectron affinity,A_1,and the ionization energy,I,of the"ancestor"system.Thus,the maximum electron acceptance is Q_(max,calc)=1+12A_1/7(I-A_1).The ground-state parabola model of the conceptual DFT yields approximately half of this value,and it is termed Q_(max,GS)=?+A_1/(I-A_1).A large variety of molecules are evaluated including fullerenes,metal clusters,super-pnictogens,super-halogens(OF_3),super-alkali species(OLi_3),and neutral or charged transition-metal complexes,AB_(m )L_n^(0/+/-).The calculated second electron affinity A_(2,calc)=A_1-(7/12)(I-A_1)is linearly correlated to the literature references A_(2,lit) with a correlation coefficient R=0.998.A_2 or A_3 values are predicted for further 24 species.The appearance sizes,n_(ap)^(3-),of triply charged anionic clusters and fullerenes are calculated in agreement with the literature.展开更多
In this study a hovel metal ion affinity ligand was immobility onto the sensor chip. Three poly-histidine peptides were used to study the interaction of tile peptides and the immobilised metal ion affinity ligand via ...In this study a hovel metal ion affinity ligand was immobility onto the sensor chip. Three poly-histidine peptides were used to study the interaction of tile peptides and the immobilised metal ion affinity ligand via biosensor system . The results obtained in this study indicate that the affinity of immobilised Ni(Ⅱ) ion affinity ligand for these peptides appear to be related to the arrangement of the histidine residues in the peptides. This study first documents the application of biosensor technique for paptide screening.展开更多
针对高渗透可再生能源接入的交直流混合配电网经济性和灵活调节性不足的问题,提出一种配合降压变压器(step down transformer,SDT)和电压源型变换器(voltage source converter,VSC)调压策略的含混合储能系统(hybrid energy storage syst...针对高渗透可再生能源接入的交直流混合配电网经济性和灵活调节性不足的问题,提出一种配合降压变压器(step down transformer,SDT)和电压源型变换器(voltage source converter,VSC)调压策略的含混合储能系统(hybrid energy storage system,HESS)交直流配电网日级别经济运行优化方法。首先,基于有功/无功-电压综合灵敏度对配电网进行分区,确定HESS的接入容量与位置;其次,基于希尔伯特-黄变换(Hilbert-Huang transform,HHT)原理对由锂电池和超级电容构成的HESS进行功率分配;然后,建立了计及HESS全生命周期的运行成本和主网购电成本的交直流混流配电网日级别经济运行优化模型;最后,对该典型二阶锥规划问题进行求解。改进IEEE33节点交直流混合配电网仿真实验表明:在合理选址定容基础上,HESS在平抑系统高频功率信号及经济性上优势明显;HESS联合SDT及VSC电压控制,可以有效降低HESS运行中出现的电压偏离程度,减小了电压约束对HESS充放电过程的影响,并进一步提升了含储能配电网经济运行能力及电压稳定性。展开更多
Fault diagnosis plays an important role in complicated industrial process.It is a challenging task to detect,identify and locate faults quickly and accurately for large-scale process system.To solve the problem,a nove...Fault diagnosis plays an important role in complicated industrial process.It is a challenging task to detect,identify and locate faults quickly and accurately for large-scale process system.To solve the problem,a novel Multi Boost-based integrated ENN(extension neural network) fault diagnosis method is proposed.Fault data of complicated chemical process have some difficult-to-handle characteristics,such as high-dimension,non-linear and non-Gaussian distribution,so we use margin discriminant projection(MDP) algorithm to reduce dimensions and extract main features.Then,the affinity propagation(AP) clustering method is used to select core data and boundary data as training samples to reduce memory consumption and shorten learning time.Afterwards,an integrated ENN classifier based on Multi Boost strategy is constructed to identify fault types.The artificial data sets are tested to verify the effectiveness of the proposed method and make a detailed sensitivity analysis for the key parameters.Finally,a real industrial system—Tennessee Eastman(TE) process is employed to evaluate the performance of the proposed method.And the results show that the proposed method is efficient and capable to diagnose various types of faults in complicated chemical process.展开更多
Endotoxins(also known as lipopolysaccharides(LPS)) are undesirable by-products of recombinant proteins,purified from Escherichia coli.LPS can be considered stable under a wide range of temperature and pH,making their ...Endotoxins(also known as lipopolysaccharides(LPS)) are undesirable by-products of recombinant proteins,purified from Escherichia coli.LPS can be considered stable under a wide range of temperature and pH,making their removal one of the most difficult tasks in downstream processes during protein purification.The inherent toxicity of LPS makes their removal an important step for the application of these proteins in several biological assays and for a safe parenteral administration.Immobilized metal affinity chromatography(IMAC) enables the affinity interactions between the metal ions(immobilized on the support through the chelating compound) and the target molecules,thus enabling high-efficiency separation of the target molecules from other components present in a mixture.Affinity chromatography is applied with Ca2+-iminodiacetic acid(IDA) to remove most of the LPS contaminants from the end product(more than90%).In this study,the adsorption of LPS on an IDA-Ca2+ was investigated.The adsorption Freundlich isotherm of LPS-IDA-Ca2+ provides a theoretical basis for LPS removal.It was found that LPS is bound mainly by interactions between the phosphate group in LPS and Ca2+ ligands on the beads.The factors such as pH(4.0 or 5.5) and ionic strength(1.0 mol/L) are essential to obtain effective removal of LPS for contaminant levels between endotoxin' concentration values less than100 EU/mL and 100 000 EU/mL.This new protocol represents a substantial advantage in time,effort,and production costs.展开更多
Two soluble copolymers of fluorenone and dioctoxylbenzene （PFN） or anthracene （PFNAn） were synthesized through Heck polymerization, and were characterized by gel permeation chromatography （GPC）, FT-IR, IH-NMR, e...Two soluble copolymers of fluorenone and dioctoxylbenzene （PFN） or anthracene （PFNAn） were synthesized through Heck polymerization, and were characterized by gel permeation chromatography （GPC）, FT-IR, IH-NMR, elemental analysis and thermogravimetric analysis. The polymers possess good solubility in common organic solvents and high thermal stability with the Onset decomposition temperature at higher than 410 ℃. The photophysical properties of the polymers were investigated in both solutions and spin-coated films. Cyclic voltammetry results revealed that the copolymers possess higher electron affinity and reversible reduction/re-oxidation processes. Their electroluminescent properties were further investigated. PFN and PFNAn show stable and saturated red light emission with high thermal stability and high electron injection ability. This type of conjugated polymers may be promising for the applications as electron acceptors in polymer photovoltaic cells and electron transporting materials.展开更多
基金This work was supported by the National Natural Science Foundation of China(71771034,71901011,71971039)the Scientific and Technological Innovation Foundation of Dalian(2018J11CY009).
文摘Affinity propagation(AP)is a classic clustering algorithm.To improve the classical AP algorithms,we propose a clustering algorithm namely,adaptive spectral affinity propagation(AdaSAP).In particular,we discuss why AP is not suitable for non-spherical clusters and present a unifying view of nine famous arbitrary-shaped clustering algorithms.We propose a strategy of extending AP in non-spherical clustering by constructing category similarity of objects.Leveraging the monotonicity that the clusters’number increases with the self-similarity in AP,we propose a model selection procedure that can determine the number of clusters adaptively.For the parameters introduced by extending AP in non-spherical clustering,we provide a grid-evolving strategy to optimize them automatically.The effectiveness of AdaSAP is evaluated by experiments on both synthetic datasets and real-world clustering tasks.Experimental results validate that the superiority of AdaSAP over benchmark algorithms like the classical AP and spectral clustering algorithms.
文摘Leaves of a Metasequoia glyptostroboides tree in Paomu Village,Longshan County,Hunan Province (Paomu Tree) possess"Even Type"cuticles and frill-margined stomata similar to those of fossil Metasequoia by far known but different from all other living Metasequoia trees(common trees).Paomu Tree is thus hypothesized as the real"living fossil",which has been supported by preliminary DNA analyses. Techniques of clearing leaf,epidermis stripping,
基金This work is supported by the Natural Science Foundation of Fujian Province, China.
文摘In this paper a negative electron affinity （NEA） multialkali photocathode of （Na<sub>2</sub>KSb-Cs）-O-Cs structure is fabricated by new technology. It is found that its emission stability is much better than that of the NEA GaAs photocathode, but is inferior to that of the conventional Na<sub>2</sub>KSb（Cs）. After 70 hour performance in a pumping vacuum system, the emission sensitivity of the NEA （Na<sub>2</sub>KSb-Cs）-O-Cs photocathode drops only by 2.5%. The emission stability is closely related to the states of the activation cesium and oxygen during activation, best results being obtained with cesium ions and excited oxygen. Furthermore, better photoemission sensitivity and emission stability may be obtained if the cathode is illuminated by intense white light during the activation process. The performance of the NEA （Na<sub>2</sub>KSb-Cs）-O-Cs cathode which has not been illuminated by intense white light during activation may be improved by the illumination even during operation intermission.
文摘Integrins are heterodimers that mediate cell adhesion and transduce signals bidirectionally across the cell membrane.Integrins often exist in low affinity(or inactive) states for
文摘[Objective]Crop line extraction is critical for improving the efficiency of autonomous agricultural machines in the field.However,traditional detection methods struggle to maintain high accuracy and efficiency under challenging conditions,such as strong light exposure and weed interference.The aims are to develop an effective crop line extraction method by combining YOLOv8-G,Affinity Propagation,and the Least Squares method to enhance detection accuracy and performance in complex field environments.[Methods]The proposed method employs machine vision techniques to address common field challenges.YOLOv8-G,an improved object detection algorithm that combines YOLOv8 and Ghost‐NetV2 for lightweight,high-speed performance,was used to detect the central points of crops.These points were then clustered using the Affinity Propagation algorithm,followed by the application of the Least Squares method to extract the crop lines.Comparative tests were conducted to evaluate multiple backbone networks within the YOLOv8 framework,and ablation studies were performed to validate the enhancements made in YOLOv8-G.[Results and Discussions]The performance of the proposed method was compared with classical object detection and clustering algorithms.The YOLOv8-G algorithm achieved average precision(AP)values of 98.22%,98.15%,and 97.32%for corn detection at 7,14,and 21 days after emergence,respectively.Additionally,the crop line extraction accuracy across all stages was 96.52%.These results demonstrate the model's ability to maintain high detection accuracy despite challenging conditions in the field.[Conclusions]The proposed crop line extraction method effectively addresses field challenges such as lighting and weed interference,enabling rapid and accurate crop identification.This approach supports the automatic navigation of agricultural machinery,offering significant improvements in the precision and efficiency of field operations.
文摘The addition of electrons to form gas-phase multiply charged anions(MCAs)normally requires sophisticated experiments or calculations.In this work,the factors stabilizing the MCAs,the maximum electron uptake of gas-phase molecules,X,and the electronic stability of MCAs X^(Q-),are discussed.The drawbacks encountered when applying computational and/or conceptual density functional theory(DFT)to MCAs are highlighted.We develop and test a different model based on the valence-state concept.As in DFT,the electronic energy,E(N,v_(ex)),is a continuous function of the average electron number,N,and the external potential,v_(ex),of the nuclei.The valence-state-parabola is a second-order polynomial that allows extending E(N,v_(ex))to dianions and higher MCAs.The model expresses the maximum electron acceptance,Q_(max),and the higher electron affinities,A_Q,as simple functions of the firstelectron affinity,A_1,and the ionization energy,I,of the"ancestor"system.Thus,the maximum electron acceptance is Q_(max,calc)=1+12A_1/7(I-A_1).The ground-state parabola model of the conceptual DFT yields approximately half of this value,and it is termed Q_(max,GS)=?+A_1/(I-A_1).A large variety of molecules are evaluated including fullerenes,metal clusters,super-pnictogens,super-halogens(OF_3),super-alkali species(OLi_3),and neutral or charged transition-metal complexes,AB_(m )L_n^(0/+/-).The calculated second electron affinity A_(2,calc)=A_1-(7/12)(I-A_1)is linearly correlated to the literature references A_(2,lit) with a correlation coefficient R=0.998.A_2 or A_3 values are predicted for further 24 species.The appearance sizes,n_(ap)^(3-),of triply charged anionic clusters and fullerenes are calculated in agreement with the literature.
文摘In this study a hovel metal ion affinity ligand was immobility onto the sensor chip. Three poly-histidine peptides were used to study the interaction of tile peptides and the immobilised metal ion affinity ligand via biosensor system . The results obtained in this study indicate that the affinity of immobilised Ni(Ⅱ) ion affinity ligand for these peptides appear to be related to the arrangement of the histidine residues in the peptides. This study first documents the application of biosensor technique for paptide screening.
文摘针对高渗透可再生能源接入的交直流混合配电网经济性和灵活调节性不足的问题,提出一种配合降压变压器(step down transformer,SDT)和电压源型变换器(voltage source converter,VSC)调压策略的含混合储能系统(hybrid energy storage system,HESS)交直流配电网日级别经济运行优化方法。首先,基于有功/无功-电压综合灵敏度对配电网进行分区,确定HESS的接入容量与位置;其次,基于希尔伯特-黄变换(Hilbert-Huang transform,HHT)原理对由锂电池和超级电容构成的HESS进行功率分配;然后,建立了计及HESS全生命周期的运行成本和主网购电成本的交直流混流配电网日级别经济运行优化模型;最后,对该典型二阶锥规划问题进行求解。改进IEEE33节点交直流混合配电网仿真实验表明:在合理选址定容基础上,HESS在平抑系统高频功率信号及经济性上优势明显;HESS联合SDT及VSC电压控制,可以有效降低HESS运行中出现的电压偏离程度,减小了电压约束对HESS充放电过程的影响,并进一步提升了含储能配电网经济运行能力及电压稳定性。
基金Project (61203021) supported by the National Natural Science Foundation of ChinaProject (2011216011) supported by the Key Science and Technology Program of Liaoning Province,China+1 种基金Project (2013020024) supported by the Natural Science Foundation of Liaoning Province,ChinaProject (LJQ2015061) supported by the Program for Liaoning Excellent Talents in Universities,China
文摘Fault diagnosis plays an important role in complicated industrial process.It is a challenging task to detect,identify and locate faults quickly and accurately for large-scale process system.To solve the problem,a novel Multi Boost-based integrated ENN(extension neural network) fault diagnosis method is proposed.Fault data of complicated chemical process have some difficult-to-handle characteristics,such as high-dimension,non-linear and non-Gaussian distribution,so we use margin discriminant projection(MDP) algorithm to reduce dimensions and extract main features.Then,the affinity propagation(AP) clustering method is used to select core data and boundary data as training samples to reduce memory consumption and shorten learning time.Afterwards,an integrated ENN classifier based on Multi Boost strategy is constructed to identify fault types.The artificial data sets are tested to verify the effectiveness of the proposed method and make a detailed sensitivity analysis for the key parameters.Finally,a real industrial system—Tennessee Eastman(TE) process is employed to evaluate the performance of the proposed method.And the results show that the proposed method is efficient and capable to diagnose various types of faults in complicated chemical process.
基金supported by grants from the Brazilian Agency Coordination of Graduate Level Training(CAPES,project 0366/09-9)State of So Paulo Research Support Foundation(FAPESP-Brazil,project 2005/60159-7)
文摘Endotoxins(also known as lipopolysaccharides(LPS)) are undesirable by-products of recombinant proteins,purified from Escherichia coli.LPS can be considered stable under a wide range of temperature and pH,making their removal one of the most difficult tasks in downstream processes during protein purification.The inherent toxicity of LPS makes their removal an important step for the application of these proteins in several biological assays and for a safe parenteral administration.Immobilized metal affinity chromatography(IMAC) enables the affinity interactions between the metal ions(immobilized on the support through the chelating compound) and the target molecules,thus enabling high-efficiency separation of the target molecules from other components present in a mixture.Affinity chromatography is applied with Ca2+-iminodiacetic acid(IDA) to remove most of the LPS contaminants from the end product(more than90%).In this study,the adsorption of LPS on an IDA-Ca2+ was investigated.The adsorption Freundlich isotherm of LPS-IDA-Ca2+ provides a theoretical basis for LPS removal.It was found that LPS is bound mainly by interactions between the phosphate group in LPS and Ca2+ ligands on the beads.The factors such as pH(4.0 or 5.5) and ionic strength(1.0 mol/L) are essential to obtain effective removal of LPS for contaminant levels between endotoxin' concentration values less than100 EU/mL and 100 000 EU/mL.This new protocol represents a substantial advantage in time,effort,and production costs.
基金Projects(50803074, 50633050) supported by the National Natural Science Foundation of ChinaProject supported by the Opening Fund of State Key Laboratory of Powder MetallurgyStart-up Fund of Central South University, China
文摘Two soluble copolymers of fluorenone and dioctoxylbenzene （PFN） or anthracene （PFNAn） were synthesized through Heck polymerization, and were characterized by gel permeation chromatography （GPC）, FT-IR, IH-NMR, elemental analysis and thermogravimetric analysis. The polymers possess good solubility in common organic solvents and high thermal stability with the Onset decomposition temperature at higher than 410 ℃. The photophysical properties of the polymers were investigated in both solutions and spin-coated films. Cyclic voltammetry results revealed that the copolymers possess higher electron affinity and reversible reduction/re-oxidation processes. Their electroluminescent properties were further investigated. PFN and PFNAn show stable and saturated red light emission with high thermal stability and high electron injection ability. This type of conjugated polymers may be promising for the applications as electron acceptors in polymer photovoltaic cells and electron transporting materials.
