Spodoptera frugiperda is a highly destructive pest that has become a global problem due to its robust reproductive and migratory capabilities.Transient receptor potential(TRP)channels,which constitute a vast ion chann...Spodoptera frugiperda is a highly destructive pest that has become a global problem due to its robust reproductive and migratory capabilities.Transient receptor potential(TRP)channels,which constitute a vast ion channel family,play pivotal roles in sensing the external environment and maintaining internal homeostasis in insects.TRP channels have been widely investigated for their critical roles in regulating various insect behaviors in recent years.In this study,we identified 15 TRP gene loci encoding 26 transcripts in the genome of S.frugiperda and analyzed their expression profiles at different developmental stages.The results revealed that S.frugiperda possesses four TRPC genes,six TRPA genes,one TRPM gene,two TRPV genes,one TRPN gene,and one TRPML gene,while a canonical TRPP is absent.Moreover,the SfruTRPA1 was functionally characterized using the Xenopus oocyte expression system.The results showed that SfruTRPA1 is activated by temperature increases from 20 to 45℃,and there is no significant desensitization after repeated stimuli within the same temperature range.Additionally,SfruTRPA1 is activated by certain natural chemicals,including allyl isothiocyanate(AITC)and cinnamaldehyde(CA).These findings provide valuable insights to the TRP genes in S.frugiperda.展开更多
Dissolved organic matter (DOM) is closely linked to human activities in drainage basins and plays a crucial role in maintaining ecosystem functioning and reflecting environmental quality. However, the impacts of clima...Dissolved organic matter (DOM) is closely linked to human activities in drainage basins and plays a crucial role in maintaining ecosystem functioning and reflecting environmental quality. However, the impacts of climate and anthropogenic-induced changes on DOM in riverine systems under increasingly warming conditions still need to be better understood, particularly at large regional scales. To address this knowledge gap, we analyzed a dataset containing 386 published measurements for nine major Chinese river systems, examining dissolved organic carbon (DOC) concentrations and optical properties of chromophoric DOM (CDOM) under diverse envi- ronmental conditions, including mean air temperature, precipitation, surface solar radiation, population density, and land use. Our findings indicate that riverine DOC concentrations are significantly higher in northern China (at ∼46.8%) than in the south. This disparity is primarily due to the high input of soil erosion-induced DOM from drying-affected lands (57.0%), farmland (49.1%), and forests in the north. The high temperate and strong hydrological conditions would lead to DOM degradation easily in the riverine system in the south of China. Our study highlights that various climatic and anthropogenic factors, such as agriculture, vegetation coverage, soil erosion, surface solar radiation, and precipitation, individually or in combination, can affect DOM dynamics in river systems. Therefore, considering alterations in DOM dynamics resulting from climate and environmental changes is crucial for carbon-neutral policies and sustainable river ecosystem assessments.展开更多
Surface tension is one of important physical features of melt alloy. Many properties of melt alloy, such as graphite shape of cast iron and modified microstructure of aluminum alloy, can be evaluated by means of surfa...Surface tension is one of important physical features of melt alloy. Many properties of melt alloy, such as graphite shape of cast iron and modified microstructure of aluminum alloy, can be evaluated by means of surface tension. In order to evaluate and control the melt quality in-situ melting operation, the authors advanced a new method and developed an automatic device for fast measuring surface tension of melt alloy and applied it to the practice of rapid identifying graphite shape of cast iron. In this paper, the principle of fast measuring surface tension, the construction of the automatic measurement device and the examples of evaluating graphite shape of cast iron based on the new method and device are discussed.展开更多
In recent years,one-dimensional(1D)nanomaterials have raised researcher's interest because of their unique structur-al characteristic to generate and confine the optical signal and their promising prospects in pho...In recent years,one-dimensional(1D)nanomaterials have raised researcher's interest because of their unique structur-al characteristic to generate and confine the optical signal and their promising prospects in photonic applications.In this re-view,we summarized the recent research advances on the spectroscopy and carrier dynamics of 1D nanostructures.First,the condensation and propagation of exciton-polaritons in nanowires(NWs)are introduced.Second,we discussed the properties of 1D photonic crystal(PC)and applications in photonic-plasmonic structures.Third,the observation of topological edge states in 1D topological structures is introduced.Finally,the perspective on the potential opportunities and remaining chal-lenges of 1D nanomaterials is proposed.展开更多
A wireless signal transmission technology based on acoustic carrier is proposed,which overcomes the limitation of electromagnetic signal shielding and shows great potential for in-site monitoring of sliding electrical...A wireless signal transmission technology based on acoustic carrier is proposed,which overcomes the limitation of electromagnetic signal shielding and shows great potential for in-site monitoring of sliding electrical contact used in gas-insulated switchgear(GIS)/gasinsulated transmission line(GIL).Here,the state parameter of the sliding electrical contact is modulated onto the frequency domain of an ultrasound wave.As a mechanical wave,the ultrasonic wave is immune to electromagnetic shielding,so that it could carry the sensing signal to penetrate the metal shielding layer and transmit to the external terminals of GIS/GIL.The principle and signal modulation process of the acoustic carrier based transmission system have been demonstrated in detail.Both simulation and experiment have been conducted to analyse the system characteristics as well as optimise the system configuration.As a proof-of-concept application,the in situ and on-line monitoring of the thermal rise of a slide electrical contact both in a current loading equivalent model and a prototype of GIS is demonstrated.Experimental results fit well with the physical process,and show a good measurement accuracy of 0.6%and tem-perature sensitivity of 400 Hz/℃.展开更多
Molecular imaging is a non-invasive method to image and analyze the concentration and activity of functional biomolecules in cells or in vivo at molecular level,and plays an increasing role in deep understanding of bi...Molecular imaging is a non-invasive method to image and analyze the concentration and activity of functional biomolecules in cells or in vivo at molecular level,and plays an increasing role in deep understanding of biological processes,early and accurate diagnosis of diseases,and evaluation of treatment.Nowadays,numerous novel molecular imaging probes have been developed,involving every biomedical imaging modality,such as optical imaging,photoacoustic imaging,magnetic resonance imaging,single-photon-emission computed tomography,and positron emission tomography.In this review,we summarize the development of current state-of-the-art molecular imaging probes.We introduce the design strategies of molecular probes and detailed imaging modalities,and highlight the properties of probes and biomedical imaging applications in cells and in vivo,including disease diagnosis,drug tracking,and imaging-guided surgery.Then we discuss the perspectives and challenges in this emerging field.We expect this review could inspire more effective molecular imaging probes to be developed,achieving the goal towards clinical practices.展开更多
Recently,holographic multiple-input multiple-output(HMIMO)has motivated its potential use to support high-capacity data transmission with spatially quasi-continuous apertures.As a practical instance of HMIMO,reconfigu...Recently,holographic multiple-input multiple-output(HMIMO)has motivated its potential use to support high-capacity data transmission with spatially quasi-continuous apertures.As a practical instance of HMIMO,reconfigurable refractive surfaces(RRSs)equipped with numerous metamaterial elements are utilized as antennas by refracting incident signals from signal sources.In this paper,we investigate a multi-user communication system with an RRS deployed as the base station(BS)’s transmit antenna.To mitigate the high overhead of accurate channel state information(CSI)acquisition,the codebook design and beam training are employed to perform beamforming.Given the large scale of RRS,users are likely to be randomly distributed in both the near and far fields around the BS,which is unknown in advance.By considering radiation characteristics in both fields,a near-far field codebook is designed to be applicable to all users,regardless of their locations.To reduce overhead,a multi-user beam training is proposed to serve all users simultaneously by enhancing each codeword capable of covering multiple areas.Considering a general case that includes users in both fields,simulation results indicate that,without prior knowledge of user distribution,the proposed scheme outperforms state-of-the-art ones in terms of sum rate and overhead.展开更多
Polycrystalline samples La_(0.9-x)EuxSr_(0.1)MnO_3(x = 0.000, 0.075) were prepared by the standard solid-state reaction method. The results show that the samples preform a characteristic of clusters spin-glass state a...Polycrystalline samples La_(0.9-x)EuxSr_(0.1)MnO_3(x = 0.000, 0.075) were prepared by the standard solid-state reaction method. The results show that the samples preform a characteristic of clusters spin-glass state at low temperature. The samples show a characteristic of ferromagnetism(FM) characteristic in the temperature range of 15-125 K and 15-150 K respectively; the samples show preformed clusters in the temperature range of 125-343 K and 150-325 K, respectively, the samples show paramagnetism(PM)characteristic above 343 and 325 K, respectively. The second-order transitions are found at 118 and 135 K for undoped and doped sample, respectively. When the applied magnetic field is 7 T, the maximum magnetic entropy change |△S_M| value of the samples is near the Curie temperature(Tc), and the value of|△S_M| reaches 2.76 and 3.03 J/(K kg), respectively. In addition, the relative cooling power(RCP) is found to be 425.28 and 443.53 J/kg. The numerical fitting data fit well with experimental data. These results indicate that both the samples have the potential to realize magnetic refrigeration in the high temperature region(T > 77 K).展开更多
Achieving full densification of some ceramic materials,such as Y_(2)O_(3),without sintering aids by spark plasma sintering(SPS)is a great challenge when plastic deformation contributes limitedly to the densification a...Achieving full densification of some ceramic materials,such as Y_(2)O_(3),without sintering aids by spark plasma sintering(SPS)is a great challenge when plastic deformation contributes limitedly to the densification as the yield stress of the material at an elevated temperature is higher than the applied sintering pressure.Herein,we demonstrate that particle fracture and rearrangement is an effective strategy to promote the densification during the pressure-assisted sintering process.Specifically,Y_(2)O_(3) nanocrystalline powders composed of nanorod and near-spherical particles were synthesized and sintered at various temperatures by the SPS.The results show that the relative density of the ceramics prepared by the nanorod powders is higher than the density of the ceramics from the near-spherical powders after 600℃ due to the fracture and rearrangement of the nanorods at low temperatures,which leads to the decrease of particle size and the increase of density and homogeneity.Based on this novel densification mechanism,ultrafine-grained Y_(2)O_(3) transparent ceramics with good optical and mechanical properties were fabricated successfully from the nanorod powders.展开更多
The present study evaluates a simulation of the global ocean mixed layer depth (MLD) using the First Institute of Oceanography-Earth System Model (FIO- ESM). The seasonal variation of the global MLD from the FIO-E...The present study evaluates a simulation of the global ocean mixed layer depth (MLD) using the First Institute of Oceanography-Earth System Model (FIO- ESM). The seasonal variation of the global MLD from the FIO-ESM simulation is compared to Argo observational data. The Argo data show that the global ocean MLD has a strong seasonal variation with a deep MLD in winter and a shallow MLD in summer, while the spring and fall seasons act as transitional periods. Overall, the FIO-ESM simula- tion accurately captures the seasonal variation in MLD in most areas. It exhibits a better performance during summer and fall than during winter and spring. The simulated MLD in the Southern Hemisphere is much closer to observations than that in the Northern Hemisphere. In general, the simulated MLD over the South Atlantic Ocean matches the observation best among the six areas. Additionally, the model slightly underestimates the MLD in parts of the North Atlantic Ocean, and slightly overestimates the MLD over the other ocean basins.展开更多
As the first attempt,this paper proposes a model for the Chinese high school timetabling problems(CHSTPs)under the new curriculum innovation which was launched in 2011 by the Chine6e government.Aooording 10 the new ou...As the first attempt,this paper proposes a model for the Chinese high school timetabling problems(CHSTPs)under the new curriculum innovation which was launched in 2011 by the Chine6e government.Aooording 10 the new our riculum innovation,students in high school can choose subjects that they are interested in instead of being forced to select one of the two study directions,namely,Science and Liberal Arts.Meanwhile,they also need to attend compulsory subjects as traditions.CHSTPs are student-oriented and involve more student constraints that make them more complex than the typi-cal"Class-Teacher model",in which the element"Teacher"is the primary constraint.In this paper,we first describe in detail the mathematical model of CHSTPs and then design a new two-part representation for the candidate solution.Based on the new representation,we adopt a two-phase simulated annealing(SA)algorithm to solve CHSTPs.A total number of 45 synthetic instances with different amounts of classes,teachers,and levels of student constraints are generated and used to ilustrate the characteristics of the CHSTP model and the effectiveness of the designed representation and algorithm.Finally,we apply the proposed model,the designed two-part representation and the two-phase SA on10 real high schools.展开更多
Cells are the basic structural and functional units of organisms.Dynamic analysis and manipulation of specific components in living cells would provide valuable information for the study of related biological processe...Cells are the basic structural and functional units of organisms.Dynamic analysis and manipulation of specific components in living cells would provide valuable information for the study of related biological processes.Advances in fluorescence microscopy have allowed real-time monitoring of biological events at the molecular level.Meanwhile,the development of highperformance fluorescence probes has become a critical issue.Functional nucleic acids(FNAs)are oligonucleotides with special chemical and biological functions,and aptamers with excellent molecular recognition capability are one of the most important representatives.They have attracted extensive attention in the field of live-cell study,owing to intrinsic advantages of simple synthesis,convenient modification,low immunogenicity and high programmability.This review focuses on recent research progress in fluorescence imaging and manipulation of cells using FNAs,particularly aptamers,as the molecular tools.Finally,a summary is provided and the related challenges are discussed.展开更多
In this work,six novel axially unfixed biaryl-based water-compatible bifunctional organocatalysts were de-signed and synthesized for the organocatalytic access to a variety of 3-alkyl-3-hydroxy-2-oxindole derivatives ...In this work,six novel axially unfixed biaryl-based water-compatible bifunctional organocatalysts were de-signed and synthesized for the organocatalytic access to a variety of 3-alkyl-3-hydroxy-2-oxindole derivatives via aldol reactions in water.Organocatalyzed by 5a,the direct aldol reactions of isatins with enolisable ketones under-went readily in water,furnishing the structurally diverse 3-alkyl-3-hydroxy-2-oxindoles in various stereoselectivi-ties(up to>99%dr and>99%ee).Moreover,a plausible transition state of the conducted aldol reactions was hy-pothesized to shed light on the observed stereoselectivities of the obtained 3-alkyl-3-hydroxy-2-oxindoles.展开更多
A high performance sample-and-hold(S/H) circuit used in a pipelined analog-to-digital converter(ADC) is presented in this paper. Fully-differential capacitor flip-around architecture was used in this S/H circuit.A gai...A high performance sample-and-hold(S/H) circuit used in a pipelined analog-to-digital converter(ADC) is presented in this paper. Fully-differential capacitor flip-around architecture was used in this S/H circuit.A gain-boosted folded cascode operational transconductance amplifier(OTA) with a DC gain of 90 dB and a GBW of 738 MHz was designed. A low supply voltage bootstrapped switch was used to improve the linearity of the S/H circuit. With these techniques, the designed S/H circuit can reach 94 dB SFDR for a 48.9 MHz input frequency with 100 MS/s sampling rate. Measurement results of a 14-bit 100-MS/s pipeline ADC with designed S/H circuit are presented.展开更多
Lactoferrin(LF)shows good anticancer biological activity.Lactoferrin can combine with chlorogenic acid(CGA)in dairy drinks like milk coffee and milk tea.However,the nature and functional changes of LF after binding of...Lactoferrin(LF)shows good anticancer biological activity.Lactoferrin can combine with chlorogenic acid(CGA)in dairy drinks like milk coffee and milk tea.However,the nature and functional changes of LF after binding of CGA are not clear.The stability and binding properties of CGA on LF and its antiproliferative effect on colorectal cancer SW480 cells were investigated by spectroscopic and cell experiments.The results showed that CGA could stabilize LF solution by reducing particle size(below 90 nm)and increasing zeta potential(over 14 in the absolute value).With addition of CGA,the UV absorption peak of LF solution changed(from 287 nm shifted to 290 nm)and fluorescence quenching occurred at the same time.By molecular dynamics calculation,the binding site number of CGA to LF was between 2 and 3 sites.Negative Gibbs free energy of(△G=-25.75±0.84)indicated that the interaction between LF and CGA can occur spontaneously and effectively.Cell viability and apoptosis test showed that CGA and LF inhibited the growth of colorectal cancer SW480 cells in a synergistic way.Most of cells were arrested at G0/G1 phase by the CGA-LF complex.We conclude that CGA can bind to LF to form a relatively stable complex under natural conditions,which increases their antiproliferative function on colorectal cancer cells.展开更多
While 8-oxo-7,8-dihydro-2′-deoxyguanosine(dOG)on DNA G-quadruplex(G4)has been studied,the influence of 8-oxo-7,8-dihydro-guanosine(rOG)lesions on telomeric repeat-containing RNA(TERRA)G4 deserves an in-depth study.Th...While 8-oxo-7,8-dihydro-2′-deoxyguanosine(dOG)on DNA G-quadruplex(G4)has been studied,the influence of 8-oxo-7,8-dihydro-guanosine(rOG)lesions on telomeric repeat-containing RNA(TERRA)G4 deserves an in-depth study.The single-strand and guanine-rich characters of TERRA make it vulnerable to form rOG lesions.Our current study demonstrated that rOG located in the internal layer and external layer of TERRA impacted the G4 stability in different ways and perturbed RNA replication,as well as base-pair strength and stability.展开更多
基金funded by the Shenzhen Science and Technology Program,China(KQTD20180411143628272)the Special Funds for Science Technology Innovation and Industrial Development of Shenzhen Dapeng New District,China(pt202101-02)the National Key R&D Program of China(2022YFE0116500).
文摘Spodoptera frugiperda is a highly destructive pest that has become a global problem due to its robust reproductive and migratory capabilities.Transient receptor potential(TRP)channels,which constitute a vast ion channel family,play pivotal roles in sensing the external environment and maintaining internal homeostasis in insects.TRP channels have been widely investigated for their critical roles in regulating various insect behaviors in recent years.In this study,we identified 15 TRP gene loci encoding 26 transcripts in the genome of S.frugiperda and analyzed their expression profiles at different developmental stages.The results revealed that S.frugiperda possesses four TRPC genes,six TRPA genes,one TRPM gene,two TRPV genes,one TRPN gene,and one TRPML gene,while a canonical TRPP is absent.Moreover,the SfruTRPA1 was functionally characterized using the Xenopus oocyte expression system.The results showed that SfruTRPA1 is activated by temperature increases from 20 to 45℃,and there is no significant desensitization after repeated stimuli within the same temperature range.Additionally,SfruTRPA1 is activated by certain natural chemicals,including allyl isothiocyanate(AITC)and cinnamaldehyde(CA).These findings provide valuable insights to the TRP genes in S.frugiperda.
基金the National Natural Science Foun-dation of China(Grants No.41925002,42221001,42230509)received financial support from the Haihe Laboratory of Sustainable Chemical Transformations.
文摘Dissolved organic matter (DOM) is closely linked to human activities in drainage basins and plays a crucial role in maintaining ecosystem functioning and reflecting environmental quality. However, the impacts of climate and anthropogenic-induced changes on DOM in riverine systems under increasingly warming conditions still need to be better understood, particularly at large regional scales. To address this knowledge gap, we analyzed a dataset containing 386 published measurements for nine major Chinese river systems, examining dissolved organic carbon (DOC) concentrations and optical properties of chromophoric DOM (CDOM) under diverse envi- ronmental conditions, including mean air temperature, precipitation, surface solar radiation, population density, and land use. Our findings indicate that riverine DOC concentrations are significantly higher in northern China (at ∼46.8%) than in the south. This disparity is primarily due to the high input of soil erosion-induced DOM from drying-affected lands (57.0%), farmland (49.1%), and forests in the north. The high temperate and strong hydrological conditions would lead to DOM degradation easily in the riverine system in the south of China. Our study highlights that various climatic and anthropogenic factors, such as agriculture, vegetation coverage, soil erosion, surface solar radiation, and precipitation, individually or in combination, can affect DOM dynamics in river systems. Therefore, considering alterations in DOM dynamics resulting from climate and environmental changes is crucial for carbon-neutral policies and sustainable river ecosystem assessments.
文摘Surface tension is one of important physical features of melt alloy. Many properties of melt alloy, such as graphite shape of cast iron and modified microstructure of aluminum alloy, can be evaluated by means of surface tension. In order to evaluate and control the melt quality in-situ melting operation, the authors advanced a new method and developed an automatic device for fast measuring surface tension of melt alloy and applied it to the practice of rapid identifying graphite shape of cast iron. In this paper, the principle of fast measuring surface tension, the construction of the automatic measurement device and the examples of evaluating graphite shape of cast iron based on the new method and device are discussed.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDB36000000)National Natural Science Foundation of China(22073022,11874130,12074086,22173025)+3 种基金the Support by the DNL Cooperation Fund,CAS(DNL202016)China Postdoctoral Science Foundation(2022M710925)Beijing Municipal Natural Science Foundation(1222030)the CAS Instrument Development Project(No.Y950291).
文摘In recent years,one-dimensional(1D)nanomaterials have raised researcher's interest because of their unique structur-al characteristic to generate and confine the optical signal and their promising prospects in photonic applications.In this re-view,we summarized the recent research advances on the spectroscopy and carrier dynamics of 1D nanostructures.First,the condensation and propagation of exciton-polaritons in nanowires(NWs)are introduced.Second,we discussed the properties of 1D photonic crystal(PC)and applications in photonic-plasmonic structures.Third,the observation of topological edge states in 1D topological structures is introduced.Finally,the perspective on the potential opportunities and remaining chal-lenges of 1D nanomaterials is proposed.
基金National Natural Science Foundation of China,Grant/Award Number:52107163。
文摘A wireless signal transmission technology based on acoustic carrier is proposed,which overcomes the limitation of electromagnetic signal shielding and shows great potential for in-site monitoring of sliding electrical contact used in gas-insulated switchgear(GIS)/gasinsulated transmission line(GIL).Here,the state parameter of the sliding electrical contact is modulated onto the frequency domain of an ultrasound wave.As a mechanical wave,the ultrasonic wave is immune to electromagnetic shielding,so that it could carry the sensing signal to penetrate the metal shielding layer and transmit to the external terminals of GIS/GIL.The principle and signal modulation process of the acoustic carrier based transmission system have been demonstrated in detail.Both simulation and experiment have been conducted to analyse the system characteristics as well as optimise the system configuration.As a proof-of-concept application,the in situ and on-line monitoring of the thermal rise of a slide electrical contact both in a current loading equivalent model and a prototype of GIS is demonstrated.Experimental results fit well with the physical process,and show a good measurement accuracy of 0.6%and tem-perature sensitivity of 400 Hz/℃.
基金supported by the National Key R&D Program of China (2020YFA0210800, 2020YFA0909000)the National Natural Science Foundation of China (22176035, U21A20377, 21874024, 21890744, 22107027, 22074036)Shenzhen Science and Technology Program (RCBS20200714114821377)
文摘Molecular imaging is a non-invasive method to image and analyze the concentration and activity of functional biomolecules in cells or in vivo at molecular level,and plays an increasing role in deep understanding of biological processes,early and accurate diagnosis of diseases,and evaluation of treatment.Nowadays,numerous novel molecular imaging probes have been developed,involving every biomedical imaging modality,such as optical imaging,photoacoustic imaging,magnetic resonance imaging,single-photon-emission computed tomography,and positron emission tomography.In this review,we summarize the development of current state-of-the-art molecular imaging probes.We introduce the design strategies of molecular probes and detailed imaging modalities,and highlight the properties of probes and biomedical imaging applications in cells and in vivo,including disease diagnosis,drug tracking,and imaging-guided surgery.Then we discuss the perspectives and challenges in this emerging field.We expect this review could inspire more effective molecular imaging probes to be developed,achieving the goal towards clinical practices.
文摘Recently,holographic multiple-input multiple-output(HMIMO)has motivated its potential use to support high-capacity data transmission with spatially quasi-continuous apertures.As a practical instance of HMIMO,reconfigurable refractive surfaces(RRSs)equipped with numerous metamaterial elements are utilized as antennas by refracting incident signals from signal sources.In this paper,we investigate a multi-user communication system with an RRS deployed as the base station(BS)’s transmit antenna.To mitigate the high overhead of accurate channel state information(CSI)acquisition,the codebook design and beam training are employed to perform beamforming.Given the large scale of RRS,users are likely to be randomly distributed in both the near and far fields around the BS,which is unknown in advance.By considering radiation characteristics in both fields,a near-far field codebook is designed to be applicable to all users,regardless of their locations.To reduce overhead,a multi-user beam training is proposed to serve all users simultaneously by enhancing each codeword capable of covering multiple areas.Considering a general case that includes users in both fields,simulation results indicate that,without prior knowledge of user distribution,the proposed scheme outperforms state-of-the-art ones in terms of sum rate and overhead.
基金Project supported by the State Key Development Program for Basic Research of China(11164019,51562032,61565013)Inner Mongolia Natural Science Foundation(2015MS0109)+1 种基金Research Program of Sciences at Universities of Inner Mongolia Autonomous Region of China(NJZZ11166,NJZY 16237,NJZY12202)Young Science and Technology Foundation of Baotou Teachers'College(BSYKJ2014-22)
文摘Polycrystalline samples La_(0.9-x)EuxSr_(0.1)MnO_3(x = 0.000, 0.075) were prepared by the standard solid-state reaction method. The results show that the samples preform a characteristic of clusters spin-glass state at low temperature. The samples show a characteristic of ferromagnetism(FM) characteristic in the temperature range of 15-125 K and 15-150 K respectively; the samples show preformed clusters in the temperature range of 125-343 K and 150-325 K, respectively, the samples show paramagnetism(PM)characteristic above 343 and 325 K, respectively. The second-order transitions are found at 118 and 135 K for undoped and doped sample, respectively. When the applied magnetic field is 7 T, the maximum magnetic entropy change |△S_M| value of the samples is near the Curie temperature(Tc), and the value of|△S_M| reaches 2.76 and 3.03 J/(K kg), respectively. In addition, the relative cooling power(RCP) is found to be 425.28 and 443.53 J/kg. The numerical fitting data fit well with experimental data. These results indicate that both the samples have the potential to realize magnetic refrigeration in the high temperature region(T > 77 K).
基金supported by the National Natural Science Foundation of China(Nos.11802042 and 51672100)the Key Research and Development Program of Sichuan Provence(No.2020YFG0192)International Cooperation Project of Guangdong Province(No.2019A050510049).
文摘Achieving full densification of some ceramic materials,such as Y_(2)O_(3),without sintering aids by spark plasma sintering(SPS)is a great challenge when plastic deformation contributes limitedly to the densification as the yield stress of the material at an elevated temperature is higher than the applied sintering pressure.Herein,we demonstrate that particle fracture and rearrangement is an effective strategy to promote the densification during the pressure-assisted sintering process.Specifically,Y_(2)O_(3) nanocrystalline powders composed of nanorod and near-spherical particles were synthesized and sintered at various temperatures by the SPS.The results show that the relative density of the ceramics prepared by the nanorod powders is higher than the density of the ceramics from the near-spherical powders after 600℃ due to the fracture and rearrangement of the nanorods at low temperatures,which leads to the decrease of particle size and the increase of density and homogeneity.Based on this novel densification mechanism,ultrafine-grained Y_(2)O_(3) transparent ceramics with good optical and mechanical properties were fabricated successfully from the nanorod powders.
基金The present study was supported by the National Natural Science Foundation of China (Grant Nos. 41476022 and 41490643), the Startup Foundation for Introducing Talent of Nanjing University of Information Science and Technology (2013r121, 2014r072), the Program for Innovation Research and Entrepreneurship team in Jiangsu Province, and the National Programme on Global Change and Air-Sea Interaction (No. GASI- 03-IPOVAI-05). Appreciation is extended to the anonymous reviewers and the editors for their valuable comments.
文摘The present study evaluates a simulation of the global ocean mixed layer depth (MLD) using the First Institute of Oceanography-Earth System Model (FIO- ESM). The seasonal variation of the global MLD from the FIO-ESM simulation is compared to Argo observational data. The Argo data show that the global ocean MLD has a strong seasonal variation with a deep MLD in winter and a shallow MLD in summer, while the spring and fall seasons act as transitional periods. Overall, the FIO-ESM simula- tion accurately captures the seasonal variation in MLD in most areas. It exhibits a better performance during summer and fall than during winter and spring. The simulated MLD in the Southern Hemisphere is much closer to observations than that in the Northern Hemisphere. In general, the simulated MLD over the South Atlantic Ocean matches the observation best among the six areas. Additionally, the model slightly underestimates the MLD in parts of the North Atlantic Ocean, and slightly overestimates the MLD over the other ocean basins.
基金This work was supported in part by the Outstanding Young Scholar Program of National Natural Science Foundation of China(NSFC)(Grant No.61522311)in part by the General Program of NSFC(Grant No.61773300)+1 种基金in part by the Key Program of Fundamental Research Project of Natural Science of Shaanxi Province,China(2017JZ017)in part by the Doctoral Students'Short-Term Study Abroad Scholarship Fund of Xidian University.
文摘As the first attempt,this paper proposes a model for the Chinese high school timetabling problems(CHSTPs)under the new curriculum innovation which was launched in 2011 by the Chine6e government.Aooording 10 the new our riculum innovation,students in high school can choose subjects that they are interested in instead of being forced to select one of the two study directions,namely,Science and Liberal Arts.Meanwhile,they also need to attend compulsory subjects as traditions.CHSTPs are student-oriented and involve more student constraints that make them more complex than the typi-cal"Class-Teacher model",in which the element"Teacher"is the primary constraint.In this paper,we first describe in detail the mathematical model of CHSTPs and then design a new two-part representation for the candidate solution.Based on the new representation,we adopt a two-phase simulated annealing(SA)algorithm to solve CHSTPs.A total number of 45 synthetic instances with different amounts of classes,teachers,and levels of student constraints are generated and used to ilustrate the characteristics of the CHSTP model and the effectiveness of the designed representation and algorithm.Finally,we apply the proposed model,the designed two-part representation and the two-phase SA on10 real high schools.
基金supported by the National Key Research Program(2018YFC1602900,2019YFA0905800)the National Natural Science Foundation of China(NSFC 21922404)the Science and Technology Project of Hunan Province(2017XK2103,2018JJ3034,2019SK2201,2018RS3035,2020SK3008)。
文摘Cells are the basic structural and functional units of organisms.Dynamic analysis and manipulation of specific components in living cells would provide valuable information for the study of related biological processes.Advances in fluorescence microscopy have allowed real-time monitoring of biological events at the molecular level.Meanwhile,the development of highperformance fluorescence probes has become a critical issue.Functional nucleic acids(FNAs)are oligonucleotides with special chemical and biological functions,and aptamers with excellent molecular recognition capability are one of the most important representatives.They have attracted extensive attention in the field of live-cell study,owing to intrinsic advantages of simple synthesis,convenient modification,low immunogenicity and high programmability.This review focuses on recent research progress in fluorescence imaging and manipulation of cells using FNAs,particularly aptamers,as the molecular tools.Finally,a summary is provided and the related challenges are discussed.
基金We thank the Beijing Municipal Commission of Education(No.JC015001200902)the Beijing Municipal Natural Science Foundation(Nos.710201,2122008)+1 种基金the Basic Research Foundation of Beijing University of Technology(No.X4015001201101)the Funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality(No.PHR201008025)and the Doctoral Scientific Research Start-up Foundation of Beijing University of Technology(No.52015001200701)for financial supports.
文摘In this work,six novel axially unfixed biaryl-based water-compatible bifunctional organocatalysts were de-signed and synthesized for the organocatalytic access to a variety of 3-alkyl-3-hydroxy-2-oxindole derivatives via aldol reactions in water.Organocatalyzed by 5a,the direct aldol reactions of isatins with enolisable ketones under-went readily in water,furnishing the structurally diverse 3-alkyl-3-hydroxy-2-oxindoles in various stereoselectivi-ties(up to>99%dr and>99%ee).Moreover,a plausible transition state of the conducted aldol reactions was hy-pothesized to shed light on the observed stereoselectivities of the obtained 3-alkyl-3-hydroxy-2-oxindoles.
文摘A high performance sample-and-hold(S/H) circuit used in a pipelined analog-to-digital converter(ADC) is presented in this paper. Fully-differential capacitor flip-around architecture was used in this S/H circuit.A gain-boosted folded cascode operational transconductance amplifier(OTA) with a DC gain of 90 dB and a GBW of 738 MHz was designed. A low supply voltage bootstrapped switch was used to improve the linearity of the S/H circuit. With these techniques, the designed S/H circuit can reach 94 dB SFDR for a 48.9 MHz input frequency with 100 MS/s sampling rate. Measurement results of a 14-bit 100-MS/s pipeline ADC with designed S/H circuit are presented.
文摘Lactoferrin(LF)shows good anticancer biological activity.Lactoferrin can combine with chlorogenic acid(CGA)in dairy drinks like milk coffee and milk tea.However,the nature and functional changes of LF after binding of CGA are not clear.The stability and binding properties of CGA on LF and its antiproliferative effect on colorectal cancer SW480 cells were investigated by spectroscopic and cell experiments.The results showed that CGA could stabilize LF solution by reducing particle size(below 90 nm)and increasing zeta potential(over 14 in the absolute value).With addition of CGA,the UV absorption peak of LF solution changed(from 287 nm shifted to 290 nm)and fluorescence quenching occurred at the same time.By molecular dynamics calculation,the binding site number of CGA to LF was between 2 and 3 sites.Negative Gibbs free energy of(△G=-25.75±0.84)indicated that the interaction between LF and CGA can occur spontaneously and effectively.Cell viability and apoptosis test showed that CGA and LF inhibited the growth of colorectal cancer SW480 cells in a synergistic way.Most of cells were arrested at G0/G1 phase by the CGA-LF complex.We conclude that CGA can bind to LF to form a relatively stable complex under natural conditions,which increases their antiproliferative function on colorectal cancer cells.
基金supported by the National Natural Science Foundation of China(nos.21722803,91853119,21572169,21721005,91753201,21877086 and 21672165)the Hubei Natural Science Foundation for Distinguished Young Scholars(2019CFA064)+2 种基金the National Major Scientific and Technological Special Project for“Significant New Drugs Development”(2017ZX09303013)the Fundamental Research Funds for the Central Universities(2042019kf0189)the Natural Science Innovation Foundation of Wuhan University.
文摘While 8-oxo-7,8-dihydro-2′-deoxyguanosine(dOG)on DNA G-quadruplex(G4)has been studied,the influence of 8-oxo-7,8-dihydro-guanosine(rOG)lesions on telomeric repeat-containing RNA(TERRA)G4 deserves an in-depth study.The single-strand and guanine-rich characters of TERRA make it vulnerable to form rOG lesions.Our current study demonstrated that rOG located in the internal layer and external layer of TERRA impacted the G4 stability in different ways and perturbed RNA replication,as well as base-pair strength and stability.