Peanut is a major cash crop in the world. In recent years, peanut pod rot has become increasingly prevalent,resulting in significant yield and quality losses. Resistance breeding is considered a cost-effective approac...Peanut is a major cash crop in the world. In recent years, peanut pod rot has become increasingly prevalent,resulting in significant yield and quality losses. Resistance breeding is considered a cost-effective approach for managing pod rot. Previous research in the United States identified significant anatomical differences in leaves and shells among peanut cultivars with varying responses to pod rot caused by Pythium myriotylum Drechs. and Rhizoctonia solani Kuhn. However, whether similar anatomical features correlate with resistance to peanut pod rot in Laixi, Qingdao, remained unknown, where the primary causal pathogen for the disease was F. solani. In this study, nine peanut varieties with differing disease reactions to peanut pod rot were planted in the same plots.Paraffin sections of leaves and shells were prepared and stained to evaluate anatomical features, and the main agronomic traits were assessed alongside leaf spot disease ratings. All the four anatomical features, leaf palisade cell number, palisade cell width, index(palisade cell number per mm × cell width in μm), and shell lignin staining area, were measured before the onset of pod rot and were found to be negatively correlated with pod rot scores.Given the consistent and strong correlation of these anatomical features with pod rot resistance and their high heritability estimates, the pre-existing resistance could be identified even in the absence of the disease, which is particularly valuable for fields where pod rot may not occur every year. This study provided useful anatomical indicators for selecting resistance to peanut pod rot, predominantly caused by F. solani.展开更多
Perovskite solar cells(PSCs)based onα-phase FAPbI_(3)(α-FAPbI_(3))microcrystals precursor outperform those withδ-phase mi-crocrystals due to their superior crystallinity and fewer defects,makingα-phase microcrysta...Perovskite solar cells(PSCs)based onα-phase FAPbI_(3)(α-FAPbI_(3))microcrystals precursor outperform those withδ-phase mi-crocrystals due to their superior crystallinity and fewer defects,makingα-phase microcrystals precursor more advantageous for high-per-formance PSCs.However,most reported synthesis methods of perovskite microcrystals,especially for aqueous synthesis,fail to reach the energy threshold required forα-phase transformation and therefore exhibit theδphase.In this study,we introduce a novel aqueous syn-thesis method to fabricateα-FAPbI_(3) microcrystals.Our approach overcomes the energy barrier by properly heating the reaction system,enabling the direct formation ofα-FAPbI_(3) in water.This direct one-step aqueous synthesis route yieldsα-FAPbI_(3) microcrystals with su-perior phase purity,crystallinity,and minimal defect density.Combined with green anti-solvent,the high-qualityα-FAPbI_(3) microcrystals serving as exceptional precursors endow perovskite films with reduced nonradiative recombination.The PSC achieves a remarkable power conversion efficiency(PCE)of 24.43%,which is one of the highest PCE reports for using the green anti-solvent in ambient air condition.This aqueous synthesis approach shows a significant potential for scalable production of high-performance PSCs.展开更多
AP2/ERE-type transcription factors,as a type of plant-specific transcription factors,play a key role in plant biotic and abiotic stress.Meanwhile,they have been studied in many plants,but rarely in tomatoes.In this st...AP2/ERE-type transcription factors,as a type of plant-specific transcription factors,play a key role in plant biotic and abiotic stress.Meanwhile,they have been studied in many plants,but rarely in tomatoes.In this study,we performed a genome-wide analysis of the SlAP2/ERF gene family of tomato,and finally identified 29 SlAP2/ERF genes and divided them into different subfamilies.At the same time,its basic physical and chemical properties were analyzed.We also constructed phylogenetic trees with 30 Arabidopsis AP2/ERF proteins and 28 potatoes AP2/ERF proteins to ensure conservative homology between them.In addition,we mapped 29 SlAP2/ERF transcription factors on 10 different chromosomes,and identified 43 responsive plant hormones,responsive light signals,tissue-specific expression and stress response elements from 2000bp upstream of the promoter region,and we analyzed conserved motifs and gene structures of SlAP2/ERF.The tertiary structure of SlAP2/ERF protein was constructed by homology modeling,and the protein-protein interaction network was constructed based on Arabidopsis Thaliana.Finally,the expression pattern of tomato in different tissues was studied by using gene expression database,and the expression level of tomato under abiotic stress was detected by q-RT-PCR.These results provide comprehensive information for further study of the function of the SlAP2/ERF gene family.展开更多
The 3d transition-metal nickel(Ni)-based cathodes have long been widely used in rechargeable batteries for over 100 years,from Ni-based alkaline rechargeable batteries,such as nickel-cadmium(Ni-Cd)and nickel-metal hyd...The 3d transition-metal nickel(Ni)-based cathodes have long been widely used in rechargeable batteries for over 100 years,from Ni-based alkaline rechargeable batteries,such as nickel-cadmium(Ni-Cd)and nickel-metal hydride(Ni-MH)batteries,to the Ni-rich cathode featured in lithium-ion batteries(LIBs).Ni-based alkaline batteries were first invented in the 1900s,and the well-developed Ni-MH batteries were used on a large scale in Toyota Prius vehicles in the mid-1990s.Around the same time,however,Sony Corporation commercialized the first LIBs in camcorders.After temporally fading as LiCoO_(2) dominated the cathode in LIBs,nickel oxide-based cathodes eventually found their way back to the mainstreaming battery industry.The uniqueness of Ni in batteries is that it helps to deliver high energy density and great storage capacity at a low cost.This review mainly provides a comprehensive overview of the key role of Ni-based cathodes in rechargeable batteries.After presenting the physical and chemical properties of the 3d transition-metal Ni,which make it an optimal cationic redox center in the cathode of batteries,we introduce the structure,reaction mechanism,and modification of nickel hydroxide electrode in Ni-Cd and Ni-MH rechargeable batteries.We then move on to the Ni-based layered oxide cathode in LIBs,with a focus on the structure,issues,and challenges of layered oxides,LiNiO_(2),and LiNi_(1−x−y)Co_(x)Mn_(y)O_(2).The role of Ni in the electrochemical performance and thermal stability of the Ni-rich cathode is highlighted.By bridging the“old”Ni-based batteries and the“modern”Ni-rich cathode in the LIBs,this review is committed to providing insights into the Ni-based electrochemistry and material design,which have been under research and development for over 100 years.This overview would shed new light on the development of advanced Ni-containing batteries with high energy density and long cycle life.展开更多
Single-crystal silicon carbide(SiC)has been widely applied in the military and civil fields because of its excellent physical and chemical properties.However,as is typical in hard-to-machine materials,the good mechani...Single-crystal silicon carbide(SiC)has been widely applied in the military and civil fields because of its excellent physical and chemical properties.However,as is typical in hard-to-machine materials,the good mechanical properties result in surface defects and subsurface damage during precision or ultraprecision machining.In this study,single-and double-varied-load nanoscratch tests were systematically performed on single-crystal 4H-SiC using a nanoindenter system with a Berkovich indenter.The material removal characteristics and cracks under different planes,indenter directions,normal loading rates,and scratch intervals were analyzed using SEM,FIB,and a 3D profilometer,and the mechanisms of material removal and crack propagation were studied.The results showed that the Si-plane of the single-crystal 4H-SiC and edge forward indenter direction are most suitable for material removal and machining.The normal loading rate had little effect on the scratch depth,but a lower loading rate increased the ductile region and critical depth of transition.Additionally,the crack interaction and fluctuation of the depth-distance curves of the second scratch weakened with an increase in the scratch interval,the status of scratches and chips changed,and the comprehensive effects of the propagation and interaction of the three cracks resulted in material fractures and chip accumulation.The calculated and experimental values of the median crack depth also showed good consistency and relativity.Therefore,this study provides an important reference for the high-efficiency and precision machining of single-crystal SiC to ensure high accuracy and a long service life.展开更多
The ability to predict a grinding force is important to control,monitor,and optimize the grinding process.Few theoretical models were developed to predict grinding forces when a structured wheel was used in a grinding...The ability to predict a grinding force is important to control,monitor,and optimize the grinding process.Few theoretical models were developed to predict grinding forces when a structured wheel was used in a grinding process.This paper aimed to establish a single-grit cutting force model to predict the ploughing,friction and cutting forces in a grinding process.It took into the consideration of actual topography of the grinding wheel,and a theoretical grinding force model for grinding hardened AISI 52100 by the wheel with orderly-micro-grooves was proposed.The model was innovative in the sense that it represented the random thickness of undeformed chips by a probabilistic expression,and it reflected the microstructure characteristics of the structured wheel explicitly.Note that the microstructure depended on the randomness of the protruding heights and distribution density of the grits over the wheel.The proposed force prediction model was validated by surface grinding experiments,and the results showed(1)a good agreement of the predicted and measured forces and(2)a good agreement of the changes of the grinding forces along with the changes of grinding parameters in the prediction model and experiments.This research proposed a theoretical grinding force model of an electroplated grinding wheel with orderly-micro-grooves which is accurate,reliable and effective in predicting grinding forces.展开更多
To improve the bonding strength between the nickel bond and the hub of the electroplated diamond grinding wheel,a hybrid technique was proposed to combine laser prequenching steel substrate and post-electroplating nic...To improve the bonding strength between the nickel bond and the hub of the electroplated diamond grinding wheel,a hybrid technique was proposed to combine laser prequenching steel substrate and post-electroplating nickel.To validate the effectiveness of the proposed technique,AISI 1045 substrate was nickel-coated.The bonding properties between the electroplated nickel coating and substrate with or without laser-discrete-quenching were discussed comparatively by scratch,indentation,and thermal shock tests.The results show that the prequenching treatment leads to phase transformation of AISI 1045 microstructure from the mixed pearlite and ferrite phases into the martensitic phase.Since the martensitic phase is characterized as a high corrosion resistance,the interface of substrate/coating is smooth and flat in the prequenched zone,and the coating is bonded well with the steel substrate.In contrast to the steel substrate without pre-quenching treatment,the proposed technique significantly enhanced the bonding strengths of the electroplated nickel-coating.On one hand,the average hardness of electroplated nickel-coating on the laser pre-quenched zone is increased by 18.7%,and the scratch depth with the same load become narrower and shallower.On the other hand,the coefficient of friction(CoF)and the vibration amplitude are reduced,and the coating is bonded effectively with the substrate to inhibit the crack initialization at the interface.This prevents effectively the coating from peeling off and improves significantly the thermal shock resistance property.展开更多
In this paper, a robust adaptive fuzzy control scheme for a class of nonlinear system with uncertainty is proposed. First, using prior knowledge about the plant we obtain a fuzzy model, which is called the generalized...In this paper, a robust adaptive fuzzy control scheme for a class of nonlinear system with uncertainty is proposed. First, using prior knowledge about the plant we obtain a fuzzy model, which is called the generalized fuzzy hyperbolic model （GFHM）. Secondly, for the case that the states of the system are not available an observer is designed and a robust adaptive fuzzy output feedback control scheme is developed. The overall control system guarantees that the tracking error converges to a small neighborhood of origin and that all signals involved are uniformly bounded. The main advantages of the proposed control scheme are that the human knowledge about the plant under control can be used to design the controller and only one parameter in the adaptive mechanism needs to be on-line adjusted.展开更多
The isotope ratios in precipitation are associated with various meteorological processes and display obvious spatial and temporal distributions, and thus can be used as impo~_nt techniques in inversing atmospheric pro...The isotope ratios in precipitation are associated with various meteorological processes and display obvious spatial and temporal distributions, and thus can be used as impo~_nt techniques in inversing atmospheric processes, tracing vapor sources, and reflect- ing the local weather and climate conditions. The composition and distribution of stable isotopes in precipitation in China are summarized and the factors that influence isotope ratios are elucidated. An overview of related research progress in China during the past several decades is presented and the prospects for future work in this subject area are described.展开更多
In the present study, 89 porcine reproductive and respiratory syndrome virus(PRRSV) isolates in China during 2007 to 2012 were randomly selected from the GenBank genetic sequence database. Evolutionary characteristics...In the present study, 89 porcine reproductive and respiratory syndrome virus(PRRSV) isolates in China during 2007 to 2012 were randomly selected from the GenBank genetic sequence database. Evolutionary characteristics of these isolates were analyzed based on the sequences of non-struc-tural protein 2(Nsp2) and glycoprotein 5(GP5). The genetic variations of the isolates were also compared with six representative strains. The results showed that a high degree of genetic diversity exists among the PRRSV population in China. Highly pathogenic PRRSV isolates, with a discon-tinuous deletion of a 30 amino acid residue in the Nsp2 region, remained the most dominant virus throughout 2007–2012 in China. Owing to the extensive use of representative vaccine strains, natu-ral recombination events occurred between strains. Three isolates – HH08, DY, and YN-2011 – were more closely related to vaccine strains than the other isolates. Both YN-2011 and DY were the evolu-tionary products of recombination events between strains SP and CH-1R. The results of the present study provide useful information for the epidemiology of PRRSV as well as for vaccine development.展开更多
This paper proposes an additive nanomanufacturing approach to fabricate a personalized lab-on-a-chip fluorescent peptide nanoparticles （f-PNPs） array for simultaneous multi-biomarker detection that can be used in Al...This paper proposes an additive nanomanufacturing approach to fabricate a personalized lab-on-a-chip fluorescent peptide nanoparticles （f-PNPs） array for simultaneous multi-biomarker detection that can be used in Alzheimer＇s disease （AD） diagnosis. We will discuss optimization techniques for the additive nanomanufacturing process in terms of reliability, yield and manufacturing efficiency. One contribution of this paper lies in utilization of additive nanomanufacturing techniques to fabricate a patient-specific customize-designed lab-on-a-chip device for personalized AD diagnosis, which remains a major challenge for biomedical engineering. Through the integrated bio-design and bio-manufacturing process, doctor＇s check- up and computer-aided customized design are integrated into the lab-on-a-chip array for patient-specific AD diagnosis. In addition, f-PNPs with targeting moieties for personalized AD biomarkers will be self-assembled onto the customized lab-on-a- chip through the additive nanomanufacturing process, which has not been done before. Another contribution of this research is the personalized lab-on-a-chip f-PNPs array for AD diagnosis utilizing limited human blood. Blood-based AD assessment has been described as ＂the holy grail＂ of early AD detection. This research created the computer-aided design, fabrication through additive nanomanufacturing, and validation of the f-PNPs array for AD diagnosis. This is a highly interdisciplinary research contributing to nanotechnology, biomaterials, and biomedical engineering for neurodegenerative disease. The conceptual work is preliminary with intent to introduce novel techniques to the application. Large-scale manufacturing based on the proposed framework requires extensive validation and optimization.展开更多
The satellite-based water vapor stable isotope measurements have been widely used in modern hydrological and atmospheric studies.Their use is important for arid areas where the precipitation events are limited,and bel...The satellite-based water vapor stable isotope measurements have been widely used in modern hydrological and atmospheric studies.Their use is important for arid areas where the precipitation events are limited,and below-cloud evaporation is strong.This study presents the spatial and temporal characteristics of water vapor isotopologue across the Tianshan Mountains in arid central Asia using the NASAAura Tropospheric Emission Spectrometer(TES).The near-surface water vapor stable isotopes are enriched in summer and depleted in winter,consistent with the seasonality of precipitation isotopes.From the surface to 200 hPa,the isotope values in water vapor show a decreasing trend as the atmospheric pressure decreases and elevation rises.The vapor isotope values in the lower atmosphere in the southern basin of the Tianshan Mountains are usually higher than that in the northern basin,and the seasonal difference in vapor isotopes is slightly more significant in the southern basin.In addition,bottom vapor isotopologue in summer shows a depletion trend from west to east,consistent with the rainout effect of the westerly moisture path in central Asia.The isotopic signature provided by the TES is helpful to understand the moisture transport and below-cloud processes influencing stable water isotopes in meteoric water.展开更多
Unravelling lineage plasticity and cellular contribution to hepatocytes provides valuable information for understanding sources that fuel homeostatic renewal of the liver(Miyajima et al.,2014).In the adult stage,hepat...Unravelling lineage plasticity and cellular contribution to hepatocytes provides valuable information for understanding sources that fuel homeostatic renewal of the liver(Miyajima et al.,2014).In the adult stage,hepatocytes are mainly self-renewed through cell division(Schaub et al.,2014;Tarlow et al.,2014;Yanger et al.,2014).Under severe injury or when hepatocyte proliferation is significantly impaired,cholangiocytes or biliary epithelial cells contribute to hepatocytes(Raven et al.,2017;Deng et al.,2018).展开更多
In this paper, we focus on the space-inhomogeneous three-state on the one-dimension lattice, a one-phase model and a two-phase model include. By using the transfer matrices method by Endo et al., we calculate the stat...In this paper, we focus on the space-inhomogeneous three-state on the one-dimension lattice, a one-phase model and a two-phase model include. By using the transfer matrices method by Endo et al., we calculate the stationary measure for initial state concrete eigenvalue. Finally we found the transfer matrices method is more effective for the three-state quantum walks than the method obtained by Kawai et al.展开更多
基金support from Mining Stress Tolerant Early Maturing Peanut Genetic Resources and Breeding Processing Type Peanut Varieties in Xinjiang(2022A02008-3)China Agricultural Research System(CARS-13)+1 种基金Agricultural Science&Technology Innovation Project of Shandong Academy of Agricultural Sciences(CXGC2024D19)Key Research&Development Program of Shandong Province(2024TSGC0532).
文摘Peanut is a major cash crop in the world. In recent years, peanut pod rot has become increasingly prevalent,resulting in significant yield and quality losses. Resistance breeding is considered a cost-effective approach for managing pod rot. Previous research in the United States identified significant anatomical differences in leaves and shells among peanut cultivars with varying responses to pod rot caused by Pythium myriotylum Drechs. and Rhizoctonia solani Kuhn. However, whether similar anatomical features correlate with resistance to peanut pod rot in Laixi, Qingdao, remained unknown, where the primary causal pathogen for the disease was F. solani. In this study, nine peanut varieties with differing disease reactions to peanut pod rot were planted in the same plots.Paraffin sections of leaves and shells were prepared and stained to evaluate anatomical features, and the main agronomic traits were assessed alongside leaf spot disease ratings. All the four anatomical features, leaf palisade cell number, palisade cell width, index(palisade cell number per mm × cell width in μm), and shell lignin staining area, were measured before the onset of pod rot and were found to be negatively correlated with pod rot scores.Given the consistent and strong correlation of these anatomical features with pod rot resistance and their high heritability estimates, the pre-existing resistance could be identified even in the absence of the disease, which is particularly valuable for fields where pod rot may not occur every year. This study provided useful anatomical indicators for selecting resistance to peanut pod rot, predominantly caused by F. solani.
基金financially supported by the National Key Research and Development Program of China(No.2022YFB3803300)the Major Scientific and Technological Project in 2022 of Changsha,China(No.kq2301002).
文摘Perovskite solar cells(PSCs)based onα-phase FAPbI_(3)(α-FAPbI_(3))microcrystals precursor outperform those withδ-phase mi-crocrystals due to their superior crystallinity and fewer defects,makingα-phase microcrystals precursor more advantageous for high-per-formance PSCs.However,most reported synthesis methods of perovskite microcrystals,especially for aqueous synthesis,fail to reach the energy threshold required forα-phase transformation and therefore exhibit theδphase.In this study,we introduce a novel aqueous syn-thesis method to fabricateα-FAPbI_(3) microcrystals.Our approach overcomes the energy barrier by properly heating the reaction system,enabling the direct formation ofα-FAPbI_(3) in water.This direct one-step aqueous synthesis route yieldsα-FAPbI_(3) microcrystals with su-perior phase purity,crystallinity,and minimal defect density.Combined with green anti-solvent,the high-qualityα-FAPbI_(3) microcrystals serving as exceptional precursors endow perovskite films with reduced nonradiative recombination.The PSC achieves a remarkable power conversion efficiency(PCE)of 24.43%,which is one of the highest PCE reports for using the green anti-solvent in ambient air condition.This aqueous synthesis approach shows a significant potential for scalable production of high-performance PSCs.
基金the National Natural Science Foundation of China(31560663,32060401).
文摘AP2/ERE-type transcription factors,as a type of plant-specific transcription factors,play a key role in plant biotic and abiotic stress.Meanwhile,they have been studied in many plants,but rarely in tomatoes.In this study,we performed a genome-wide analysis of the SlAP2/ERF gene family of tomato,and finally identified 29 SlAP2/ERF genes and divided them into different subfamilies.At the same time,its basic physical and chemical properties were analyzed.We also constructed phylogenetic trees with 30 Arabidopsis AP2/ERF proteins and 28 potatoes AP2/ERF proteins to ensure conservative homology between them.In addition,we mapped 29 SlAP2/ERF transcription factors on 10 different chromosomes,and identified 43 responsive plant hormones,responsive light signals,tissue-specific expression and stress response elements from 2000bp upstream of the promoter region,and we analyzed conserved motifs and gene structures of SlAP2/ERF.The tertiary structure of SlAP2/ERF protein was constructed by homology modeling,and the protein-protein interaction network was constructed based on Arabidopsis Thaliana.Finally,the expression pattern of tomato in different tissues was studied by using gene expression database,and the expression level of tomato under abiotic stress was detected by q-RT-PCR.These results provide comprehensive information for further study of the function of the SlAP2/ERF gene family.
基金financially supported by the China Postdoctoral Science Foundation(No.2021M700396)the National Natural Science Foundation of China(No.52102206)。
文摘The 3d transition-metal nickel(Ni)-based cathodes have long been widely used in rechargeable batteries for over 100 years,from Ni-based alkaline rechargeable batteries,such as nickel-cadmium(Ni-Cd)and nickel-metal hydride(Ni-MH)batteries,to the Ni-rich cathode featured in lithium-ion batteries(LIBs).Ni-based alkaline batteries were first invented in the 1900s,and the well-developed Ni-MH batteries were used on a large scale in Toyota Prius vehicles in the mid-1990s.Around the same time,however,Sony Corporation commercialized the first LIBs in camcorders.After temporally fading as LiCoO_(2) dominated the cathode in LIBs,nickel oxide-based cathodes eventually found their way back to the mainstreaming battery industry.The uniqueness of Ni in batteries is that it helps to deliver high energy density and great storage capacity at a low cost.This review mainly provides a comprehensive overview of the key role of Ni-based cathodes in rechargeable batteries.After presenting the physical and chemical properties of the 3d transition-metal Ni,which make it an optimal cationic redox center in the cathode of batteries,we introduce the structure,reaction mechanism,and modification of nickel hydroxide electrode in Ni-Cd and Ni-MH rechargeable batteries.We then move on to the Ni-based layered oxide cathode in LIBs,with a focus on the structure,issues,and challenges of layered oxides,LiNiO_(2),and LiNi_(1−x−y)Co_(x)Mn_(y)O_(2).The role of Ni in the electrochemical performance and thermal stability of the Ni-rich cathode is highlighted.By bridging the“old”Ni-based batteries and the“modern”Ni-rich cathode in the LIBs,this review is committed to providing insights into the Ni-based electrochemistry and material design,which have been under research and development for over 100 years.This overview would shed new light on the development of advanced Ni-containing batteries with high energy density and long cycle life.
基金Supported by National Natural Science Foundation of China(Grant No.51405034)Changsha Municipal Natural Science Foundation of China(Grant No.kq2202200)Hunan Provincial High-tech Industry Science and Technology Innovation Leading Program of China(Grant No.2022GK4027).
文摘Single-crystal silicon carbide(SiC)has been widely applied in the military and civil fields because of its excellent physical and chemical properties.However,as is typical in hard-to-machine materials,the good mechanical properties result in surface defects and subsurface damage during precision or ultraprecision machining.In this study,single-and double-varied-load nanoscratch tests were systematically performed on single-crystal 4H-SiC using a nanoindenter system with a Berkovich indenter.The material removal characteristics and cracks under different planes,indenter directions,normal loading rates,and scratch intervals were analyzed using SEM,FIB,and a 3D profilometer,and the mechanisms of material removal and crack propagation were studied.The results showed that the Si-plane of the single-crystal 4H-SiC and edge forward indenter direction are most suitable for material removal and machining.The normal loading rate had little effect on the scratch depth,but a lower loading rate increased the ductile region and critical depth of transition.Additionally,the crack interaction and fluctuation of the depth-distance curves of the second scratch weakened with an increase in the scratch interval,the status of scratches and chips changed,and the comprehensive effects of the propagation and interaction of the three cracks resulted in material fractures and chip accumulation.The calculated and experimental values of the median crack depth also showed good consistency and relativity.Therefore,this study provides an important reference for the high-efficiency and precision machining of single-crystal SiC to ensure high accuracy and a long service life.
基金Supported by National Natural Science Foundation of China(Grant Nos.52275405,52275311,51875050)Hunan Provincial Key Research and Development Program(Grant No.2021GK2021).
文摘The ability to predict a grinding force is important to control,monitor,and optimize the grinding process.Few theoretical models were developed to predict grinding forces when a structured wheel was used in a grinding process.This paper aimed to establish a single-grit cutting force model to predict the ploughing,friction and cutting forces in a grinding process.It took into the consideration of actual topography of the grinding wheel,and a theoretical grinding force model for grinding hardened AISI 52100 by the wheel with orderly-micro-grooves was proposed.The model was innovative in the sense that it represented the random thickness of undeformed chips by a probabilistic expression,and it reflected the microstructure characteristics of the structured wheel explicitly.Note that the microstructure depended on the randomness of the protruding heights and distribution density of the grits over the wheel.The proposed force prediction model was validated by surface grinding experiments,and the results showed(1)a good agreement of the predicted and measured forces and(2)a good agreement of the changes of the grinding forces along with the changes of grinding parameters in the prediction model and experiments.This research proposed a theoretical grinding force model of an electroplated grinding wheel with orderly-micro-grooves which is accurate,reliable and effective in predicting grinding forces.
基金the National Natural Science Foundation of China(No.51875050)Hunan Provincial Natural Science Foundation of China(No.2019JJ40293)Changsha City Planned Science and Technology Project(No.kq1907088)。
文摘To improve the bonding strength between the nickel bond and the hub of the electroplated diamond grinding wheel,a hybrid technique was proposed to combine laser prequenching steel substrate and post-electroplating nickel.To validate the effectiveness of the proposed technique,AISI 1045 substrate was nickel-coated.The bonding properties between the electroplated nickel coating and substrate with or without laser-discrete-quenching were discussed comparatively by scratch,indentation,and thermal shock tests.The results show that the prequenching treatment leads to phase transformation of AISI 1045 microstructure from the mixed pearlite and ferrite phases into the martensitic phase.Since the martensitic phase is characterized as a high corrosion resistance,the interface of substrate/coating is smooth and flat in the prequenched zone,and the coating is bonded well with the steel substrate.In contrast to the steel substrate without pre-quenching treatment,the proposed technique significantly enhanced the bonding strengths of the electroplated nickel-coating.On one hand,the average hardness of electroplated nickel-coating on the laser pre-quenched zone is increased by 18.7%,and the scratch depth with the same load become narrower and shallower.On the other hand,the coefficient of friction(CoF)and the vibration amplitude are reduced,and the coating is bonded effectively with the substrate to inhibit the crack initialization at the interface.This prevents effectively the coating from peeling off and improves significantly the thermal shock resistance property.
基金supported by the National Natural Science Foundation of China(No.21825302,No.21903076)the Taishan Scholar Program of Shandong Province of China(tsqn201909122)。
基金This work was supported by the National Natural Science Foundation of China (No.60325311, 60534010, 60572070)the Foundation for Doctoral Special Branch by the Ministry of Education of China (20011045023)Shenyang City Science Foundation (1022033-1-07)
文摘In this paper, a robust adaptive fuzzy control scheme for a class of nonlinear system with uncertainty is proposed. First, using prior knowledge about the plant we obtain a fuzzy model, which is called the generalized fuzzy hyperbolic model （GFHM）. Secondly, for the case that the states of the system are not available an observer is designed and a robust adaptive fuzzy output feedback control scheme is developed. The overall control system guarantees that the tracking error converges to a small neighborhood of origin and that all signals involved are uniformly bounded. The main advantages of the proposed control scheme are that the human knowledge about the plant under control can be used to design the controller and only one parameter in the adaptive mechanism needs to be on-line adjusted.
基金supported by the National Natural Science Foundation of China (No. 41161012)the Program for New Century Excellent Talents in University by the Education Ministry of China (No. NCET-10-0019)
文摘The isotope ratios in precipitation are associated with various meteorological processes and display obvious spatial and temporal distributions, and thus can be used as impo~_nt techniques in inversing atmospheric processes, tracing vapor sources, and reflect- ing the local weather and climate conditions. The composition and distribution of stable isotopes in precipitation in China are summarized and the factors that influence isotope ratios are elucidated. An overview of related research progress in China during the past several decades is presented and the prospects for future work in this subject area are described.
基金supported by the Jilin Province Science and Technology Development Project(No.20140101123JC)the Fundamental Research Fund of Jilin Universitythe Program for Changjiang Scholars and Innovative Research Team in University(No.IRT1248)
文摘In the present study, 89 porcine reproductive and respiratory syndrome virus(PRRSV) isolates in China during 2007 to 2012 were randomly selected from the GenBank genetic sequence database. Evolutionary characteristics of these isolates were analyzed based on the sequences of non-struc-tural protein 2(Nsp2) and glycoprotein 5(GP5). The genetic variations of the isolates were also compared with six representative strains. The results showed that a high degree of genetic diversity exists among the PRRSV population in China. Highly pathogenic PRRSV isolates, with a discon-tinuous deletion of a 30 amino acid residue in the Nsp2 region, remained the most dominant virus throughout 2007–2012 in China. Owing to the extensive use of representative vaccine strains, natu-ral recombination events occurred between strains. Three isolates – HH08, DY, and YN-2011 – were more closely related to vaccine strains than the other isolates. Both YN-2011 and DY were the evolu-tionary products of recombination events between strains SP and CH-1R. The results of the present study provide useful information for the epidemiology of PRRSV as well as for vaccine development.
文摘This paper proposes an additive nanomanufacturing approach to fabricate a personalized lab-on-a-chip fluorescent peptide nanoparticles （f-PNPs） array for simultaneous multi-biomarker detection that can be used in Alzheimer＇s disease （AD） diagnosis. We will discuss optimization techniques for the additive nanomanufacturing process in terms of reliability, yield and manufacturing efficiency. One contribution of this paper lies in utilization of additive nanomanufacturing techniques to fabricate a patient-specific customize-designed lab-on-a-chip device for personalized AD diagnosis, which remains a major challenge for biomedical engineering. Through the integrated bio-design and bio-manufacturing process, doctor＇s check- up and computer-aided customized design are integrated into the lab-on-a-chip array for patient-specific AD diagnosis. In addition, f-PNPs with targeting moieties for personalized AD biomarkers will be self-assembled onto the customized lab-on-a- chip through the additive nanomanufacturing process, which has not been done before. Another contribution of this research is the personalized lab-on-a-chip f-PNPs array for AD diagnosis utilizing limited human blood. Blood-based AD assessment has been described as ＂the holy grail＂ of early AD detection. This research created the computer-aided design, fabrication through additive nanomanufacturing, and validation of the f-PNPs array for AD diagnosis. This is a highly interdisciplinary research contributing to nanotechnology, biomaterials, and biomedical engineering for neurodegenerative disease. The conceptual work is preliminary with intent to introduce novel techniques to the application. Large-scale manufacturing based on the proposed framework requires extensive validation and optimization.
基金This research was supported by the National Natural Science Foundation of China(Nos.41971034 and 41701028)the Foundation for Distinguished Young Scholars of Gansu Province(No.20JR10RA112)the Northwest Normal University(No.NWNU LKZD2021-04)。
文摘The satellite-based water vapor stable isotope measurements have been widely used in modern hydrological and atmospheric studies.Their use is important for arid areas where the precipitation events are limited,and below-cloud evaporation is strong.This study presents the spatial and temporal characteristics of water vapor isotopologue across the Tianshan Mountains in arid central Asia using the NASAAura Tropospheric Emission Spectrometer(TES).The near-surface water vapor stable isotopes are enriched in summer and depleted in winter,consistent with the seasonality of precipitation isotopes.From the surface to 200 hPa,the isotope values in water vapor show a decreasing trend as the atmospheric pressure decreases and elevation rises.The vapor isotope values in the lower atmosphere in the southern basin of the Tianshan Mountains are usually higher than that in the northern basin,and the seasonal difference in vapor isotopes is slightly more significant in the southern basin.In addition,bottom vapor isotopologue in summer shows a depletion trend from west to east,consistent with the rainout effect of the westerly moisture path in central Asia.The isotopic signature provided by the TES is helpful to understand the moisture transport and below-cloud processes influencing stable water isotopes in meteoric water.
基金supported by the National Key Research and Development Program of China(2018YFA0107900 and 2018YFA0108100)the National Science Foundation of China(31730112 and 31625019)the China Postdoctoral Innovative Talent Support Program。
文摘Unravelling lineage plasticity and cellular contribution to hepatocytes provides valuable information for understanding sources that fuel homeostatic renewal of the liver(Miyajima et al.,2014).In the adult stage,hepatocytes are mainly self-renewed through cell division(Schaub et al.,2014;Tarlow et al.,2014;Yanger et al.,2014).Under severe injury or when hepatocyte proliferation is significantly impaired,cholangiocytes or biliary epithelial cells contribute to hepatocytes(Raven et al.,2017;Deng et al.,2018).
文摘In this paper, we focus on the space-inhomogeneous three-state on the one-dimension lattice, a one-phase model and a two-phase model include. By using the transfer matrices method by Endo et al., we calculate the stationary measure for initial state concrete eigenvalue. Finally we found the transfer matrices method is more effective for the three-state quantum walks than the method obtained by Kawai et al.
