The emergence of new media in various fields has continuously strengthened the social aspect of social media.Netizens tend to express emotions in social interactions,and many people even use satire,metaphors,and other...The emergence of new media in various fields has continuously strengthened the social aspect of social media.Netizens tend to express emotions in social interactions,and many people even use satire,metaphors,and other techniques to express some negative emotions,it is necessary to detect sarcasm in social comment data.For sarcasm,the more reference data modalities used,the better the experimental effect.This paper conducts research on sarcasm detection technology based on image-text fusion data.To effectively utilize the features of each modality,a feature reconstruction output algorithm is proposed.This algorithm is based on the attention mechanism,learns the low-rank features of another modality through cross-modality,the eigenvectors are reconstructed for the corresponding modality through weighted averaging.When only the image modality in the dataset is used,the preprocessed data has outstanding performance in reconstructing the output model,with an accuracy rate of 87.6%.When using only the text modality data in the dataset,the reconstructed output model is optimal,with an accuracy rate of 85.2%.To improve feature fusion between modalities for effective classification,a weight adaptive learning algorithm is used.This algorithm uses a neural network combined with an attention mechanism to calculate the attention weight of each modality to achieve weight adaptive learning purposes,with an accuracy rate of 87.9%.Extensive experiments on a benchmark dataset demonstrate the superiority of our proposed model.展开更多
Grinding is a crucial process in machining workpieces because it plays a vital role in achieving the desired precision and surface quality.However,a significant technical challenge in grinding is the potential increas...Grinding is a crucial process in machining workpieces because it plays a vital role in achieving the desired precision and surface quality.However,a significant technical challenge in grinding is the potential increase in temperature due to high specific energy,which can lead to surface thermal damage.Therefore,ensuring control over the surface integrity of workpieces during grinding becomes a critical concern.This necessitates the development of temperature field models that consider various parameters,such as workpiece materials,grinding wheels,grinding parameters,cooling methods,and media,to guide industrial production.This study thoroughly analyzes and summarizes grinding temperature field models.First,the theory of the grinding temperature field is investigated,classifying it into traditional models based on a continuous belt heat source and those based on a discrete heat source,depending on whether the heat source is uniform and continuous.Through this examination,a more accurate grinding temperature model that closely aligns with practical grinding conditions is derived.Subsequently,various grinding thermal models are summarized,including models for the heat source distribution,energy distribution proportional coefficient,and convective heat transfer coefficient.Through comprehensive research,the most widely recognized,utilized,and accurate model for each category is identified.The application of these grinding thermal models is reviewed,shedding light on the governing laws that dictate the influence of the heat source distribution,heat distribution,and convective heat transfer in the grinding arc zone on the grinding temperature field.Finally,considering the current issues in the field of grinding temperature,potential future research directions are proposed.The aim of this study is to provide theoretical guidance and technical support for predicting workpiece temperature and improving surface integrity.展开更多
Metsbolites generated by microalgac cell metabolism have practical application value in the fields of medicine, food, feed and energy. At present, with the development of genetic engineering techniques and continuous ...Metsbolites generated by microalgac cell metabolism have practical application value in the fields of medicine, food, feed and energy. At present, with the development of genetic engineering techniques and continuous reduction in gene sequencing costs, some micrcalgal genomes have been successively published, which enables specific genetic modification of microalgae according to human's demand and provides broad application prospects. In this paper, different mediating systems and emerging genome editing techniques were summarized, which laid the foundation for the application of genetic engineering methods for microalgae.展开更多
Using analytical method, this paper gets 'the mutual inductance between coil and workpiece in tube blank electromagnetic bulging. According to this, we obtain the optimum locations of tube blank with different len...Using analytical method, this paper gets 'the mutual inductance between coil and workpiece in tube blank electromagnetic bulging. According to this, we obtain the optimum locations of tube blank with different length of coil and workpiece. There is a good agreement between results calculated and the experimental data.展开更多
Phytohormones,epigenetic regulation and environmental factors regulate fruit ripening but their interplay during strawberry fruit ripening remains to be determined.In this study,bagged strawberry fruit exhibited delay...Phytohormones,epigenetic regulation and environmental factors regulate fruit ripening but their interplay during strawberry fruit ripening remains to be determined.In this study,bagged strawberry fruit exhibited delayed ripening compared with fruit grown in normal light,correlating with reduced abscisic acid(ABA) accumulation.Transcription of the key ABA catabolism gene,ABA 8′-hydroxylase FaCYP707A4,was induced in bagged fruit.With light exclusion whole genome DNA methylation levels were up-regulated,corresponding to a delayed ripening process,while DNA methylation levels in the promoter of FaCYP707A4 were suppressed,correlating with increases in transcript and decreased ABA content.Experiments indicated FaCRY1,a blue light receptor repressed in bagged fruit and FaAGO4,a key protein involved in RNA-directed DNA methylation,could bind to the promoter of FaCYP707A4.The interaction between FaCRY1 and FaAGO4,and an increased enrichment of FaAGO4 directed to the FaCYP707A4 promoter in fruit grown under light suggests FaCRY1 may influence FaAGO4 to modulate the DNA methylation status of the FaCYP707A4 promoter.Furthermore,transient overexpression of FaCRY1,or an increase in FaCRY1 transcription by blue light treatment,increases the methylation level of the FaCYP707A4 promoter,while transient RNA interference of FaCRY1 displayed opposite phenotypes.These findings reveal a mechanism by which DNA methylation influences ABA catabolism,and participates in light-mediated strawberry ripening.展开更多
Corundum abrasives with good chemical stability can be fabricated into various free abrasives and bonded abrasive tools that are widely used in the precision machining of various parts.However,these abrasives cannot s...Corundum abrasives with good chemical stability can be fabricated into various free abrasives and bonded abrasive tools that are widely used in the precision machining of various parts.However,these abrasives cannot satisfy the machining requirements of difficult-to-machine materials with high hardness,high strength,and strong wearing resistance.Although superhard abrasives can machine the above-mentioned materials,their dressing and manufacturing costs are high.By contrast,ceramic corundum abrasives fabricated by sol–gel method is a costeffective product between conventional and superhard abrasives.Ceramic corundum abrasives exhibit self-sharpening and high toughness.In this review,the optimization methods of ceramic corundum abrasive properties are introduced from three aspects:precursor synthesis,particle shaping,and sintering.Firstly,the functional mechanism of seeds and additives on the microstructural and mechanical properties of abrasives is analyzed.Specifically,seeds can reduce the phase transition temperature and improve fracture toughness.The grain size and uniformly dense structure can be controlled by applying an appropriate amount of multicomponent additives.Then,the urgent need of engineering application and machinability of special shape ceramic corundum abrasives is reviewed,and three methods of abrasive shaping are summarized.The micromold replication technique is highly advanced and can be used to prepare functional abrasives.Additionally,the influence of a new sintering method,namely,two-step sintering technique,on the microstructural and mechanical performance of ceramic corundum abrasives is summarized.Finally,the challenge and developmental trend of the optimization of ceramic corundum abrasives are prospected.展开更多
Coxsackievirus A10(CVA10)is one of the major causative agents of hand,foot and mouth disease(HFMD).To investigate the epidemiological characteristics as well as genetic features of CVA10 currently circulating in Shang...Coxsackievirus A10(CVA10)is one of the major causative agents of hand,foot and mouth disease(HFMD).To investigate the epidemiological characteristics as well as genetic features of CVA10 currently circulating in Shanghai,China,we collected a total of 9,952 sporadic HFMD cases from January 2016 to December 2020.In the past five years,CVA10 was the fourth prevalent causatives associated with HFMD in Shanghai and the overall positive rate was 2.78%.The annual distribution experienced significant fluctuations over the past five years.In addition to entire VP1 sequencing,complete genome sequencing and recombination analysis of CVA10 isolates in Shanghai were further performed.A total of 64 near complete genomes and 11 entire VP1 sequences in this study combined with reference sequences publicly available were integrated into phylogenetic analysis.The CVA10sequences in this study mainly belonged to genogroup C and presented 91%-100%nucleotide identity with other Chinese isolates based on VP1 region.For the first time,our study reported the appearance of CVA10 genogroup D in Chinese mainland,which had led to large-scale outbreaks in Europe previously.The recombination analysis showed the recombination break point located between 5,100 nt and 6,700 nt,which suggesting intertypic recombination with CVA16 genogroup D.To conclusion,CVA10 genogroup C was the predominant genogroup in Shanghai during 2016-2020.CVA10 recombinant genogroup D was firstly reported in circulating in Chinese mainland.Continuous surveillance is needed to better understand the evolution relationships and transmission pathways of CVA10 to help to guide disease control and prevention.展开更多
Bone grinding is an essential and vital procedure in most surgical operations.Currently,the insufficient cooling capacity of dry grinding,poor visibility of drip irrigation surgery area,and large grinding force leadin...Bone grinding is an essential and vital procedure in most surgical operations.Currently,the insufficient cooling capacity of dry grinding,poor visibility of drip irrigation surgery area,and large grinding force leading to high grinding temperature are the technical bottlenecks of micro-grinding.A new micro-grinding process called ultrasonic vibration-assisted nanoparticle jet mist cooling(U-NJMC)is innovatively proposed to solve the technical problem.It combines the advantages of ultrasonic vibration(UV)and nanoparticle jet mist cooling(NJMC).Notwithstanding,the combined effect of multi parameter collaborative of U-NJMC on cooling has not been investigated.The grinding force,friction coefficient,specific grinding energy,and grinding temperature under dry,drip irrigation,UV,minimum quantity lubrication(MQL),NJMC,and U-NJMC micro-grinding were compared and analyzed.Results showed that the minimum normal grinding force and tangential grinding force of U-NJMC micro-grinding were 1.39 and 0.32 N,which were 75.1%and 82.9%less than those in dry grinding,respectively.The minimum friction coefficient and specific grinding energy were achieved using U-NJMC.Compared with dry,drip,UV,MQL,and NJMC grinding,the friction coefficient of U-NJMC was decreased by 31.3%,17.0%,19.0%,9.8%,and 12.5%,respectively,and the specific grinding energy was decreased by 83.0%,72.7%,77.8%,52.3%,and 64.7%,respectively.Compared with UV or NJMC alone,the grinding temperature of U-NJMC was decreased by 33.5%and 10.0%,respectively.These results showed that U-NJMC provides a novel approach for clinical surgical micro-grinding of biological bone.展开更多
In the present work Mn3O4/reduced graphene oxide hydrogel (Mn3O4-rGOH) with three dimensional (3D) networks was fabricated by a hydrothermal self-assembly route. The morphology, composition, and microstructure of ...In the present work Mn3O4/reduced graphene oxide hydrogel (Mn3O4-rGOH) with three dimensional (3D) networks was fabricated by a hydrothermal self-assembly route. The morphology, composition, and microstructure of the as-obtained samples were characterized using powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry analysis (TG), atomic absorption spectrometry (AAS), field emission scanning electron microscopy (FESEM) and transmission electron microscope (TEM). Moreover, the electrochemical behaviors were evaluated by cyclic voltammogram (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS). The test results indicated that the hydrogel with 6.9% Mn3O4 achieved specific capacitance of 148 F.g^-1 at a specific current of 1 A.g^-1, and showed excellent cycling stabilily with no decay after 1200 cycles. In addition, its specific capacitance could retain 70% even at 20 A.g^- 1 in comparison with that at 1 A.g ^-1 and the operating window was up to 1.8 V in a neutral electrolyte.展开更多
Soybean and maize are important raw materials for the production of food and livestock feed.Accurate mapping of these two crops is of great significance to crop management,yield estimation,and crop-damage control.In t...Soybean and maize are important raw materials for the production of food and livestock feed.Accurate mapping of these two crops is of great significance to crop management,yield estimation,and crop-damage control.In this study,two towns in Guoyang County,Anhui Province,China,were selected as the study area,and Sentinel-2 images were adopted to map the distributions of both crops in the 2019 growing season.The data obtained on August 18(early pod-setting stage of soybean)was determined to be the most applicable to soybean and maize mapping by means of the Jeffries-Matusita(JM)distance.Subsequently,three machine-learning algorithms,i.e.,random forest(RF),support vector machine(SVM)and back-propagation neural network(BPNN)were employed and their respective performance in crop identification was evaluated with the aid of 254 ground truth plots.It appeared that RF with a Kappa of 0.83 was superior to the other two methods.Furthermore,twenty candidate features containing the reflectance of ten spectral bands(spatial resolution at 10 m or 20 m)and ten remote-sensing indices were input into the RF algorithm to conduct an important assessment.Seven features were screened out and served as the optimum subset,the mapping results of which were assessed based on the ground truth derived from the unmanned aerial vehicle(UAV)images covering six ground samples.The optimum feature-subset achieved high-accuracy crop mapping,with a reduction of data volume by 65%compared with the total twenty features,which also overrode the performance of ten spectral bands.Therefore,feature-optimization had great potential in the identification of the two crops.Generally,the findings of this study can provide a valuable reference for mapping soybean and maize in areas with a fragmented landscape of farmland and complex planting structure.展开更多
肠杆菌共同抗原(Enterobacterial common antigen,ECA)是由多糖重复单元组成的多聚糖,几乎表达于所有肠杆菌细菌外膜,具有生物学功能。ECA由多基因协同作用而合成,这些基因在肠杆菌细菌基因组上成簇存在,形成ECA抗原基因簇。ECA是重要...肠杆菌共同抗原(Enterobacterial common antigen,ECA)是由多糖重复单元组成的多聚糖,几乎表达于所有肠杆菌细菌外膜,具有生物学功能。ECA由多基因协同作用而合成,这些基因在肠杆菌细菌基因组上成簇存在,形成ECA抗原基因簇。ECA是重要的毒力因子,在肠杆菌细菌入侵宿主、体内存活等过程中有一定作用。同时,ECA在维持细菌外膜渗透屏障、鞭毛表达、群集运动及抗胆酸胆盐等方面也有重要作用。此外,锚定在细菌脂多糖核心区的ECALPS还是细菌重要的表面抗原,能激发宿主产生高水平抗体,可以作为疫苗研究的靶点。结合笔者的研究,文中对ECA纯化、基因结构和合成、免疫特性、生物学功能及应用等方面进行了综述。展开更多
Chemical oxidation is used to cut and unzip multi-walled carbon nanotubes in the transverse direction and the axial direction to form graphene oxide nanoribbon (GONR). Ruthenium oxide/reduced graphene oxide nanoribb...Chemical oxidation is used to cut and unzip multi-walled carbon nanotubes in the transverse direction and the axial direction to form graphene oxide nanoribbon (GONR). Ruthenium oxide/reduced graphene oxide nanoribbon composite (RuO2/rGONR) with a 72.5 wt% RuO2 loading is synthesized through an aqueous-phase reaction, in which GONR is served as starting material, followed by mild thermal treatment in ambient air. The resulting RuO2/rGONR composite achieves specific capacitance up to 677 F.g l at the current density of 1 A·g^-1 in three-electrode system using 1 mol·L^-1 H2SO4 as electrolyte. The resultant electrode exhibits an excellent rate capability (91.8% retention rate at 20 A·g^-1). Especially, the symmetric supercapacitor assembled on the basis of RuO2/rGONR electrode delivers high energy density (16.2 Wh·kg^-1) even at the power density of 9885 W·kg^-1, which is very essential for supercapacitors.展开更多
The reduced graphene oxide(RGO)/bisphenol A(BPA)composites were prepared by an adsorption-reduction method.The composites are characterized by X-ray diffraction(XRD),UV-vis,thermogravimetric(TG)analysis,field emission...The reduced graphene oxide(RGO)/bisphenol A(BPA)composites were prepared by an adsorption-reduction method.The composites are characterized by X-ray diffraction(XRD),UV-vis,thermogravimetric(TG)analysis,field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM).The results confirm that BPA is adsorbed on the basal plane of RGO byπ-πstacking interaction.Furthermore,the electrochemical behaviors were evaluated by cyclic voltammetry,galvanostatic charge/discharge techniques and electrochemical impedance spectroscopy(EIS).The results show that the RGO/BPA nanocomposites exhibit ultrahigh specific capacitance of 466 F•g^(−1) at a current density of 1 A•g^(−1),excellent rate capability(more than 81%retention at 10 A•g^(−1) relative to 1 A•g^(−1))and superior cycling stability(90%capacitance decay after 4000 cycles).Consequently,the RGO/BPA nanocomposites can be regarded as promising electrode materials for supercapacitor applications.展开更多
The organic magnetoelectric complexes are beneficial for the development on flexible magnetoelectric devices in the future.In this work,we fabricated all organic multiferroic ferromagnetic/ferroelectric complexes to s...The organic magnetoelectric complexes are beneficial for the development on flexible magnetoelectric devices in the future.In this work,we fabricated all organic multiferroic ferromagnetic/ferroelectric complexes to study magnetoelectric coupling at room temperature.Under the stimulus of external magnetic field,the localization of charge inside organic ferromagnets will be enhanced to affect spin–dipole interaction at organic multiferroic interfaces,where overall ferroelectric polarization is tuned to present an organic magnetoelectric coupling.Moreover,the magnetoelectric coupling of the organic ferromagnetic/ferroelectric complex is tightly dependent on incident light intensity.Decreasing light intensity,the dominated interfacial interaction will switch from spin–dipole to dipole–dipole interaction,which leads to the magnetoelectric coefficient changing from positive to negative in organic multiferroic magnetoelectric complexes.展开更多
Carbapenem is one of the few available drugs to treat multidrug-resistance Gram-negative bacteria infections.Recently,the plasmid-mediated spread of the carbapenem resistance gene bla_(NDM) poses a significant threat ...Carbapenem is one of the few available drugs to treat multidrug-resistance Gram-negative bacteria infections.Recently,the plasmid-mediated spread of the carbapenem resistance gene bla_(NDM) poses a significant threat to public health,requiring global monitoring and surveillance.Here,we used both short-read(n=2461)and long-read(n=546)sequencing data to characterize the global distribution of bla_(NDM).We analyzed the replicon type of bla_(NDM)-positive plasmids and found that the dominant plasmid type was different in diverse geographical locations.Although bla_(NDM)gene has been transferred across diverse countries,its genetic backgrounds are highly conserved,and the mobile genetic element ISAba125,IS5,and IS26 may play an important role in the mobilization of bla_(NDM).A significant association was observed between host origin and gene presence/deletion variation on IncX3 plasmid,which may be a key factor in the bacterial adaption to diverse hosts.In this study,we analyzed the diversity,distribution and transmission of bla_(NDM)-positive plasmids from a global perspective,and emphasize the importance of plasmid analysis for understanding the evolution and adaptation of bla_(NDM)-positive plasmids and their co-evolution with bacterial genomes(resistome).展开更多
基金funded by National Key Research and Development Program of China(No.2022YFC3302103).
文摘The emergence of new media in various fields has continuously strengthened the social aspect of social media.Netizens tend to express emotions in social interactions,and many people even use satire,metaphors,and other techniques to express some negative emotions,it is necessary to detect sarcasm in social comment data.For sarcasm,the more reference data modalities used,the better the experimental effect.This paper conducts research on sarcasm detection technology based on image-text fusion data.To effectively utilize the features of each modality,a feature reconstruction output algorithm is proposed.This algorithm is based on the attention mechanism,learns the low-rank features of another modality through cross-modality,the eigenvectors are reconstructed for the corresponding modality through weighted averaging.When only the image modality in the dataset is used,the preprocessed data has outstanding performance in reconstructing the output model,with an accuracy rate of 87.6%.When using only the text modality data in the dataset,the reconstructed output model is optimal,with an accuracy rate of 85.2%.To improve feature fusion between modalities for effective classification,a weight adaptive learning algorithm is used.This algorithm uses a neural network combined with an attention mechanism to calculate the attention weight of each modality to achieve weight adaptive learning purposes,with an accuracy rate of 87.9%.Extensive experiments on a benchmark dataset demonstrate the superiority of our proposed model.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52205481,51975305 and 52105457)Shandong Natural Science Foundation(Grant Nos.ZR2020ME158,ZR2023QE057,ZR2022QE028,ZR2021QE116,ZR2020KE027,and ZR2022QE159)+1 种基金Qingdao Science and Technology Planning Park Cultivation Plan(23-1-5-yqpy-17-qy)China Postdoctral Science Foundation(2021M701810).
文摘Grinding is a crucial process in machining workpieces because it plays a vital role in achieving the desired precision and surface quality.However,a significant technical challenge in grinding is the potential increase in temperature due to high specific energy,which can lead to surface thermal damage.Therefore,ensuring control over the surface integrity of workpieces during grinding becomes a critical concern.This necessitates the development of temperature field models that consider various parameters,such as workpiece materials,grinding wheels,grinding parameters,cooling methods,and media,to guide industrial production.This study thoroughly analyzes and summarizes grinding temperature field models.First,the theory of the grinding temperature field is investigated,classifying it into traditional models based on a continuous belt heat source and those based on a discrete heat source,depending on whether the heat source is uniform and continuous.Through this examination,a more accurate grinding temperature model that closely aligns with practical grinding conditions is derived.Subsequently,various grinding thermal models are summarized,including models for the heat source distribution,energy distribution proportional coefficient,and convective heat transfer coefficient.Through comprehensive research,the most widely recognized,utilized,and accurate model for each category is identified.The application of these grinding thermal models is reviewed,shedding light on the governing laws that dictate the influence of the heat source distribution,heat distribution,and convective heat transfer in the grinding arc zone on the grinding temperature field.Finally,considering the current issues in the field of grinding temperature,potential future research directions are proposed.The aim of this study is to provide theoretical guidance and technical support for predicting workpiece temperature and improving surface integrity.
基金Supported by National High-Tech Research and Development(863)Program of China(2014AA093501)Fund of The Institute of Seawater Desalination and Multipurpose Utilization(K-JBYWF-2015-T20)
文摘Metsbolites generated by microalgac cell metabolism have practical application value in the fields of medicine, food, feed and energy. At present, with the development of genetic engineering techniques and continuous reduction in gene sequencing costs, some micrcalgal genomes have been successively published, which enables specific genetic modification of microalgae according to human's demand and provides broad application prospects. In this paper, different mediating systems and emerging genome editing techniques were summarized, which laid the foundation for the application of genetic engineering methods for microalgae.
文摘Using analytical method, this paper gets 'the mutual inductance between coil and workpiece in tube blank electromagnetic bulging. According to this, we obtain the optimum locations of tube blank with different length of coil and workpiece. There is a good agreement between results calculated and the experimental data.
基金supported by the National Key Research and Development Program of China (2022YFD2100100)National Natural Science Foundation of China (U23A20215, 32002004)+1 种基金the 111 Project (B17039)Fundamental Research Funds for the Central University (226-2024-00063)。
文摘Phytohormones,epigenetic regulation and environmental factors regulate fruit ripening but their interplay during strawberry fruit ripening remains to be determined.In this study,bagged strawberry fruit exhibited delayed ripening compared with fruit grown in normal light,correlating with reduced abscisic acid(ABA) accumulation.Transcription of the key ABA catabolism gene,ABA 8′-hydroxylase FaCYP707A4,was induced in bagged fruit.With light exclusion whole genome DNA methylation levels were up-regulated,corresponding to a delayed ripening process,while DNA methylation levels in the promoter of FaCYP707A4 were suppressed,correlating with increases in transcript and decreased ABA content.Experiments indicated FaCRY1,a blue light receptor repressed in bagged fruit and FaAGO4,a key protein involved in RNA-directed DNA methylation,could bind to the promoter of FaCYP707A4.The interaction between FaCRY1 and FaAGO4,and an increased enrichment of FaAGO4 directed to the FaCYP707A4 promoter in fruit grown under light suggests FaCRY1 may influence FaAGO4 to modulate the DNA methylation status of the FaCYP707A4 promoter.Furthermore,transient overexpression of FaCRY1,or an increase in FaCRY1 transcription by blue light treatment,increases the methylation level of the FaCYP707A4 promoter,while transient RNA interference of FaCRY1 displayed opposite phenotypes.These findings reveal a mechanism by which DNA methylation influences ABA catabolism,and participates in light-mediated strawberry ripening.
基金the following organizations:the National Natural Science Foundation of China(Nos.51975305,51905289)the Major Research Project of Shandong Province(Nos.2019GGX104040 and2019GSF108236)+2 种基金the Shandong Provincial Natural Science Foundation of China(Nos.ZR2019PEE008)Major Science and Technology Innovation Engineering Projects of Shandong Province(No.2019JZZY020111)Applied Basic Research Youth Project of Qingdao Science and Technology Plan(No.19-6-2-63-cg)。
文摘Corundum abrasives with good chemical stability can be fabricated into various free abrasives and bonded abrasive tools that are widely used in the precision machining of various parts.However,these abrasives cannot satisfy the machining requirements of difficult-to-machine materials with high hardness,high strength,and strong wearing resistance.Although superhard abrasives can machine the above-mentioned materials,their dressing and manufacturing costs are high.By contrast,ceramic corundum abrasives fabricated by sol–gel method is a costeffective product between conventional and superhard abrasives.Ceramic corundum abrasives exhibit self-sharpening and high toughness.In this review,the optimization methods of ceramic corundum abrasive properties are introduced from three aspects:precursor synthesis,particle shaping,and sintering.Firstly,the functional mechanism of seeds and additives on the microstructural and mechanical properties of abrasives is analyzed.Specifically,seeds can reduce the phase transition temperature and improve fracture toughness.The grain size and uniformly dense structure can be controlled by applying an appropriate amount of multicomponent additives.Then,the urgent need of engineering application and machinability of special shape ceramic corundum abrasives is reviewed,and three methods of abrasive shaping are summarized.The micromold replication technique is highly advanced and can be used to prepare functional abrasives.Additionally,the influence of a new sintering method,namely,two-step sintering technique,on the microstructural and mechanical performance of ceramic corundum abrasives is summarized.Finally,the challenge and developmental trend of the optimization of ceramic corundum abrasives are prospected.
基金supported by Shanghai Sailing Program(Grant no:19YF1441500)Shanghai Municipal Commission of Health and Family Planning(Grant no:20184Y0101)Three-Year Action Plan of Shanghai Public Health System Construction(Grant no:GWV-2,GWV10.1-XK03)。
文摘Coxsackievirus A10(CVA10)is one of the major causative agents of hand,foot and mouth disease(HFMD).To investigate the epidemiological characteristics as well as genetic features of CVA10 currently circulating in Shanghai,China,we collected a total of 9,952 sporadic HFMD cases from January 2016 to December 2020.In the past five years,CVA10 was the fourth prevalent causatives associated with HFMD in Shanghai and the overall positive rate was 2.78%.The annual distribution experienced significant fluctuations over the past five years.In addition to entire VP1 sequencing,complete genome sequencing and recombination analysis of CVA10 isolates in Shanghai were further performed.A total of 64 near complete genomes and 11 entire VP1 sequences in this study combined with reference sequences publicly available were integrated into phylogenetic analysis.The CVA10sequences in this study mainly belonged to genogroup C and presented 91%-100%nucleotide identity with other Chinese isolates based on VP1 region.For the first time,our study reported the appearance of CVA10 genogroup D in Chinese mainland,which had led to large-scale outbreaks in Europe previously.The recombination analysis showed the recombination break point located between 5,100 nt and 6,700 nt,which suggesting intertypic recombination with CVA16 genogroup D.To conclusion,CVA10 genogroup C was the predominant genogroup in Shanghai during 2016-2020.CVA10 recombinant genogroup D was firstly reported in circulating in Chinese mainland.Continuous surveillance is needed to better understand the evolution relationships and transmission pathways of CVA10 to help to guide disease control and prevention.
基金supported by the National Natural Science Foundation of China (Grant Nos.51905289 and 51975305)the National Key R&D Program of China (Grant No.2020YFB2010500)+3 种基金the Natural Science Foundation of Shandong Province,China (Grant Nos.ZR2022QE159,ZR2020KE027,ZR2020ME158,and ZR2019PEE008)the China Postdoctoral Science Foundation (Grant No.2021M701810)the Innovation Talent Supporting Program for Postdoctoral Fellows of Shandong Province,China (Grant No.SDBX2020012)the Qingdao Postdoctoral Researchers Applied Research Project Funding,China (Grant No.A2020-072).
文摘Bone grinding is an essential and vital procedure in most surgical operations.Currently,the insufficient cooling capacity of dry grinding,poor visibility of drip irrigation surgery area,and large grinding force leading to high grinding temperature are the technical bottlenecks of micro-grinding.A new micro-grinding process called ultrasonic vibration-assisted nanoparticle jet mist cooling(U-NJMC)is innovatively proposed to solve the technical problem.It combines the advantages of ultrasonic vibration(UV)and nanoparticle jet mist cooling(NJMC).Notwithstanding,the combined effect of multi parameter collaborative of U-NJMC on cooling has not been investigated.The grinding force,friction coefficient,specific grinding energy,and grinding temperature under dry,drip irrigation,UV,minimum quantity lubrication(MQL),NJMC,and U-NJMC micro-grinding were compared and analyzed.Results showed that the minimum normal grinding force and tangential grinding force of U-NJMC micro-grinding were 1.39 and 0.32 N,which were 75.1%and 82.9%less than those in dry grinding,respectively.The minimum friction coefficient and specific grinding energy were achieved using U-NJMC.Compared with dry,drip,UV,MQL,and NJMC grinding,the friction coefficient of U-NJMC was decreased by 31.3%,17.0%,19.0%,9.8%,and 12.5%,respectively,and the specific grinding energy was decreased by 83.0%,72.7%,77.8%,52.3%,and 64.7%,respectively.Compared with UV or NJMC alone,the grinding temperature of U-NJMC was decreased by 33.5%and 10.0%,respectively.These results showed that U-NJMC provides a novel approach for clinical surgical micro-grinding of biological bone.
基金Acknowledgement We gratefully acknowledge the financial support offered by the National Natural Science Foundation of China (Nos. 20963009 and 21163017), the Gansu Science and Technology Committee (No. 0803RJA005), and the Postgraduate Advisor Program of Provincial Education Department of Gansu.
文摘In the present work Mn3O4/reduced graphene oxide hydrogel (Mn3O4-rGOH) with three dimensional (3D) networks was fabricated by a hydrothermal self-assembly route. The morphology, composition, and microstructure of the as-obtained samples were characterized using powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry analysis (TG), atomic absorption spectrometry (AAS), field emission scanning electron microscopy (FESEM) and transmission electron microscope (TEM). Moreover, the electrochemical behaviors were evaluated by cyclic voltammogram (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS). The test results indicated that the hydrogel with 6.9% Mn3O4 achieved specific capacitance of 148 F.g^-1 at a specific current of 1 A.g^-1, and showed excellent cycling stabilily with no decay after 1200 cycles. In addition, its specific capacitance could retain 70% even at 20 A.g^- 1 in comparison with that at 1 A.g ^-1 and the operating window was up to 1.8 V in a neutral electrolyte.
基金This work was supported by the Key Project of Natural Science Research of Education Department of Anhui Province(Grant No.KJ2019A0120)the National Key Research and Development Program of China(2019YFE0115200)+2 种基金and the Open Research Fund of National Engineering Research Center for Agro-Ecological Big Data Analysis&Application(Grant No.AE2018011)The authors appreciate the European Space Agency(ESA)which provides Sentinel-2 images for this researchthe editor and anonymous reviewers for their valuable comments that helped us to improve this manuscript.
文摘Soybean and maize are important raw materials for the production of food and livestock feed.Accurate mapping of these two crops is of great significance to crop management,yield estimation,and crop-damage control.In this study,two towns in Guoyang County,Anhui Province,China,were selected as the study area,and Sentinel-2 images were adopted to map the distributions of both crops in the 2019 growing season.The data obtained on August 18(early pod-setting stage of soybean)was determined to be the most applicable to soybean and maize mapping by means of the Jeffries-Matusita(JM)distance.Subsequently,three machine-learning algorithms,i.e.,random forest(RF),support vector machine(SVM)and back-propagation neural network(BPNN)were employed and their respective performance in crop identification was evaluated with the aid of 254 ground truth plots.It appeared that RF with a Kappa of 0.83 was superior to the other two methods.Furthermore,twenty candidate features containing the reflectance of ten spectral bands(spatial resolution at 10 m or 20 m)and ten remote-sensing indices were input into the RF algorithm to conduct an important assessment.Seven features were screened out and served as the optimum subset,the mapping results of which were assessed based on the ground truth derived from the unmanned aerial vehicle(UAV)images covering six ground samples.The optimum feature-subset achieved high-accuracy crop mapping,with a reduction of data volume by 65%compared with the total twenty features,which also overrode the performance of ten spectral bands.Therefore,feature-optimization had great potential in the identification of the two crops.Generally,the findings of this study can provide a valuable reference for mapping soybean and maize in areas with a fragmented landscape of farmland and complex planting structure.
文摘肠杆菌共同抗原(Enterobacterial common antigen,ECA)是由多糖重复单元组成的多聚糖,几乎表达于所有肠杆菌细菌外膜,具有生物学功能。ECA由多基因协同作用而合成,这些基因在肠杆菌细菌基因组上成簇存在,形成ECA抗原基因簇。ECA是重要的毒力因子,在肠杆菌细菌入侵宿主、体内存活等过程中有一定作用。同时,ECA在维持细菌外膜渗透屏障、鞭毛表达、群集运动及抗胆酸胆盐等方面也有重要作用。此外,锚定在细菌脂多糖核心区的ECALPS还是细菌重要的表面抗原,能激发宿主产生高水平抗体,可以作为疫苗研究的靶点。结合笔者的研究,文中对ECA纯化、基因结构和合成、免疫特性、生物学功能及应用等方面进行了综述。
基金Acknowledgement We gratefully acknowledge the financial support offered by the National Natural Science Foundation of China (Nos. 20963009 21163017 and 21563027) and Specialized Research Fund for the Doctoral Program of Higher Education(No. 20126203110001).
文摘Chemical oxidation is used to cut and unzip multi-walled carbon nanotubes in the transverse direction and the axial direction to form graphene oxide nanoribbon (GONR). Ruthenium oxide/reduced graphene oxide nanoribbon composite (RuO2/rGONR) with a 72.5 wt% RuO2 loading is synthesized through an aqueous-phase reaction, in which GONR is served as starting material, followed by mild thermal treatment in ambient air. The resulting RuO2/rGONR composite achieves specific capacitance up to 677 F.g l at the current density of 1 A·g^-1 in three-electrode system using 1 mol·L^-1 H2SO4 as electrolyte. The resultant electrode exhibits an excellent rate capability (91.8% retention rate at 20 A·g^-1). Especially, the symmetric supercapacitor assembled on the basis of RuO2/rGONR electrode delivers high energy density (16.2 Wh·kg^-1) even at the power density of 9885 W·kg^-1, which is very essential for supercapacitors.
基金support offered by the National Natural Science Foundation of China(Nos.20963009 and 21163017)Specialized Research Fund for the Doctoral Program of Higher Education,China(No.20126203110001).
文摘The reduced graphene oxide(RGO)/bisphenol A(BPA)composites were prepared by an adsorption-reduction method.The composites are characterized by X-ray diffraction(XRD),UV-vis,thermogravimetric(TG)analysis,field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM).The results confirm that BPA is adsorbed on the basal plane of RGO byπ-πstacking interaction.Furthermore,the electrochemical behaviors were evaluated by cyclic voltammetry,galvanostatic charge/discharge techniques and electrochemical impedance spectroscopy(EIS).The results show that the RGO/BPA nanocomposites exhibit ultrahigh specific capacitance of 466 F•g^(−1) at a current density of 1 A•g^(−1),excellent rate capability(more than 81%retention at 10 A•g^(−1) relative to 1 A•g^(−1))and superior cycling stability(90%capacitance decay after 4000 cycles).Consequently,the RGO/BPA nanocomposites can be regarded as promising electrode materials for supercapacitor applications.
基金supported by the NSFC(Grant Nos.11774203 and 91963103)Taishan Scholar Foundation of Shandong Province(tsqn201812007)+2 种基金Shandong Province Outstanding Youth Foundation(ZR2020JQ02)Major Program of Shandong Province Natural Science Foundation(ZR2019ZD43)Shandong University Multidisciplinary Research and Innovation Team of Young Scholars(2020QNQT013).
文摘The organic magnetoelectric complexes are beneficial for the development on flexible magnetoelectric devices in the future.In this work,we fabricated all organic multiferroic ferromagnetic/ferroelectric complexes to study magnetoelectric coupling at room temperature.Under the stimulus of external magnetic field,the localization of charge inside organic ferromagnets will be enhanced to affect spin–dipole interaction at organic multiferroic interfaces,where overall ferroelectric polarization is tuned to present an organic magnetoelectric coupling.Moreover,the magnetoelectric coupling of the organic ferromagnetic/ferroelectric complex is tightly dependent on incident light intensity.Decreasing light intensity,the dominated interfacial interaction will switch from spin–dipole to dipole–dipole interaction,which leads to the magnetoelectric coefficient changing from positive to negative in organic multiferroic magnetoelectric complexes.
基金supported by the Laboratory of Lingnan Modern Agriculture Project(NT2021006)National Natural Science Foundation of China(32273054).
文摘Carbapenem is one of the few available drugs to treat multidrug-resistance Gram-negative bacteria infections.Recently,the plasmid-mediated spread of the carbapenem resistance gene bla_(NDM) poses a significant threat to public health,requiring global monitoring and surveillance.Here,we used both short-read(n=2461)and long-read(n=546)sequencing data to characterize the global distribution of bla_(NDM).We analyzed the replicon type of bla_(NDM)-positive plasmids and found that the dominant plasmid type was different in diverse geographical locations.Although bla_(NDM)gene has been transferred across diverse countries,its genetic backgrounds are highly conserved,and the mobile genetic element ISAba125,IS5,and IS26 may play an important role in the mobilization of bla_(NDM).A significant association was observed between host origin and gene presence/deletion variation on IncX3 plasmid,which may be a key factor in the bacterial adaption to diverse hosts.In this study,we analyzed the diversity,distribution and transmission of bla_(NDM)-positive plasmids from a global perspective,and emphasize the importance of plasmid analysis for understanding the evolution and adaptation of bla_(NDM)-positive plasmids and their co-evolution with bacterial genomes(resistome).