Depositing single-walled carbon nanotubes(SWNTs) with controllable density, pattern and orientation on electrodes presents a challenge in today's research. Here, we report a novel solvent evaporation method to ali...Depositing single-walled carbon nanotubes(SWNTs) with controllable density, pattern and orientation on electrodes presents a challenge in today's research. Here, we report a novel solvent evaporation method to align SWNTs in patterns having nanoscale width and micronscale length. SWNTs suspension has been introduced dropwise onto photoresist resin microchannels; and the capillary force can stretch and align SWNTs into strands with nanoscale width in the microchannels. Then these narrow and long aligned SWNTs patterns were successfully transferred to a pair of gold electrodes with different gaps to fabricate carbon nanotube field-effect transistor(CNTFET). Moreover, the electrical performance of the CNTFET show that the SWNTs strands can bridge different gaps and fabricate good electrical performance CNTFET with ON/OFF ratio around 106. This result suggests a promising and simple strategy for assembling well-aligned SWNTs into CNTFET device with good electrical performance.展开更多
In this work,wemodeled the brittle fracture of shell structure in the framework of Peridynamics Mindlin-Reissener shell theory,in which the shell is described by material points in themean-plane with its drilling rota...In this work,wemodeled the brittle fracture of shell structure in the framework of Peridynamics Mindlin-Reissener shell theory,in which the shell is described by material points in themean-plane with its drilling rotation neglected in kinematic assumption.To improve the numerical accuracy,the stress-point method is utilized to eliminate the numerical instability induced by the zero-energy mode and rank-deficiency.The crack surface is represented explicitly by stress points,and a novel general crack criterion is proposed based on that.Instead of the critical stretch used in common peridynamic solid,it is convenient to describe thematerial failure by using the classic constitutive model in continuum mechanics.In this work,a concise crack simulation algorithm is also provided to describe the crack path and its development,in order to simulate the brittle fracture of the shell structure.Numerical examples are presented to validate and demonstrate our proposed model.Results reveal that our model has good accuracy and capability to represent crack propagation and branch spontaneously.展开更多
Field effect transistors (FET) based on Single-Walled Carbon Nanotubes (SWNTs) become the hot topic in fields of nano-electronic, clinical diagnostics, environmental testing etc. in recent years. In this paper, we rep...Field effect transistors (FET) based on Single-Walled Carbon Nanotubes (SWNTs) become the hot topic in fields of nano-electronic, clinical diagnostics, environmental testing etc. in recent years. In this paper, we reported a simple, scalable way to enrich semiconducting SWNTs by using HNO3/H2SO4. Then carbon nanotube field-effect transistors (CNTFET) biosensor was fabricated with the enrichment SWNTs for Escherichia coli O157︰H7 detection. The response of each CNTFET was monitored in real time before and after introduction of the Escherichia coli O157︰H7 at various concentrations. The results show that CNT-FET biosensors we fabricated are sensitive to change of concentration of solution and response time is really short.展开更多
Melamine formaldehyde (MF) foam is kind of fire-retardant material and has great potential in acoustic and thermal insulation area. In this article, MF resin foam was prepared by microwave radiation. We discussed the ...Melamine formaldehyde (MF) foam is kind of fire-retardant material and has great potential in acoustic and thermal insulation area. In this article, MF resin foam was prepared by microwave radiation. We discussed the thermal stability of MF foam and the effect of different emulsifiers on its morphology, apparent density, fire-retardancy and mechanical property. The decomposition temperature of MF foam we prepared is nearly 400℃ and the constitution of residue after combustion is made up of carbon and graphite. Emulsifier influenced the apparent density of MF foam and using coemulsifiers can get flexible foam with uniform cell size, good morphology and low apparent density. When the fire-retardant MF foam’s apparent density is low of 5.53 kg/cm-3, its value of LOI can reach 32.4. The mechanical property of foam is consistent with apparent density.展开更多
The coordination structure of cupric tartrate(Cu−TA)complex was investigated by ultraviolet−visible(UV-Vis)and liquid chromatography/mass spectrometer(LC-MS)firstly;furthermore,effective coordination configurations an...The coordination structure of cupric tartrate(Cu−TA)complex was investigated by ultraviolet−visible(UV-Vis)and liquid chromatography/mass spectrometer(LC-MS)firstly;furthermore,effective coordination configurations and electronic properties of Cu−TA in aqueous solution were systematically revealed by density functional theory(DFT)calculations.Consistently,Job plots show the possible existence of[Cu(TA)]and[Cu(TA)_(2)]^(2-)at 230 and 255 nm based on UV-Vis results.LC-MS results confirm the existence of the single and high coordination complexes[Cu_(2)(TA)_(2)]^(+),[Cu(TA)_(2)]^(+)and[Cu_(2)(TA)_(3)(H_(2)O)_(2)(OH)_(2)]^(2+).DFT calculation results show that carboxylic oxygen and hydroxyl oxygen of tartaric acid(TA)are preferred sites for Cu(Ⅱ)coordination.[Cu(TA)](1H,3H sites O of TA coordinated with Cu(Ⅱ)),[Cu(TA)_(2)]^(2-)(two 1^(C),2^(H) sites O of TA coordinated with Cu(Ⅱ)),and[Cu(TA)_(3)]^(4-)(three 2H,3H sites O of TA coordinated with Cu(Ⅱ))should be dominant coordination configurations of Cu−TA.The corresponding Gibbs reaction energies are-170.1,-136.2,and-90.2 kJ/mol,respectively.展开更多
The finite-time Mittag-Leffler synchronization is investigated for fractional-order delayed memristive neural networks(FDMNN)with parameters uncertainty and discontinuous activation functions.The relevant results are ...The finite-time Mittag-Leffler synchronization is investigated for fractional-order delayed memristive neural networks(FDMNN)with parameters uncertainty and discontinuous activation functions.The relevant results are obtained under the framework of Filippov for such systems.Firstly,the novel feedback controller,which includes the discontinuous functions and time delays,is proposed to investigate such systems.Secondly,the conditions on finite-time Mittag-Leffler synchronization of FDMNN are established according to the properties of fractional-order calculus and inequality analysis technique.At the same time,the upper bound of the settling time for Mittag-Leffler synchronization is accurately estimated.In addition,by selecting the appropriate parameters of the designed controller and utilizing the comparison theorem for fractional-order systems,the global asymptotic synchronization is achieved as a corollary.Finally,a numerical example is given to indicate the correctness of the obtained conclusions.展开更多
Besides its fundamental importance, non-reciprocity has also found many potential applications in quantum technology. Recently, many quantum systems have been proposed to realize non-reciprocity, but stable non-recipr...Besides its fundamental importance, non-reciprocity has also found many potential applications in quantum technology. Recently, many quantum systems have been proposed to realize non-reciprocity, but stable non-reciprocal process is still experimentally difficult in general, due to the needed cyclical interactions in artificial systems or operational difficulties in solid state materials. Here, we propose a new kind of interaction induced non-reciprocal operation, based on the conventional stimulated-Raman-adiabatic-passage (STIRAP) setup, which removes the experimental difficulty of requiring cyclical interaction, and thus it is directly implementable in various quantum systems. Furthermore, we also illustrate our proposal on a chain of three coupled superconducting transmons, which can lead to a non-reciprocal circulator with high fidelity without a ring coupling configuration as in the previous schemes or implementations. Therefore, our protocol provides a promising way to explore fundamental non-reciprocal quantum physics as well as realize non-reciprocal quantum device.展开更多
Without dividing the complex-valued systems into two real-valued ones, a class of fractional-order complex-valued memristive neural networks(FCVMNNs) with time delay is investigated. Firstly, based on the complex-valu...Without dividing the complex-valued systems into two real-valued ones, a class of fractional-order complex-valued memristive neural networks(FCVMNNs) with time delay is investigated. Firstly, based on the complex-valued sign function, a novel complex-valued feedback controller is devised to research such systems. Under the framework of Filippov solution, differential inclusion theory and Lyapunov stability theorem, the finite-time Mittag-Leffler synchronization(FTMLS) of FCVMNNs with time delay can be realized. Meanwhile, the upper bound of the synchronization settling time(SST) is less conservative than previous results. In addition, by adjusting controller parameters, the global asymptotic synchronization of FCVMNNs with time delay can also be realized, which improves and enrich some existing results. Lastly,some simulation examples are designed to verify the validity of conclusions.展开更多
Hypoxia-inducible factor(HIF)is a main heterodimeric transcription factor that regulates the cellular adaptive response to hypoxia by stimulating the transcription of a series of hypoxia-inducible genes.HIF is frequen...Hypoxia-inducible factor(HIF)is a main heterodimeric transcription factor that regulates the cellular adaptive response to hypoxia by stimulating the transcription of a series of hypoxia-inducible genes.HIF is frequently upregulated in solid tumors,and the overexpression of HIF can promote tumor progression or aggressiveness by blood vessel architecture and altering cellular metabolism.In this review,we focused on the pivotal role of HIF in tumor angiogenesis and energy metabolism.Furthermore,we also emphasized the possibility of HIF pathway as a potential therapeutic target in cancer.展开更多
High-fidelity quantum gates are essential for large-scale quantum computation.However,any quantum manipulation will inevitably affected by noises,systematic errors and decoherence effects,which lead to infidelity of a...High-fidelity quantum gates are essential for large-scale quantum computation.However,any quantum manipulation will inevitably affected by noises,systematic errors and decoherence effects,which lead to infidelity of a target quantum task.Therefore,implementing high-fidelity,robust and fast quantum gates is highly desired.Here,we propose a fast and robust scheme to construct high-fidelity holonomic quantum gates for universal quantum computation based on resonant interaction of three-level quantum systems via shortcuts to adiabaticity.In our proposal,the target Hamiltonian to induce noncyclic non-Abelian geometric phases can be inversely engineered with less evolution time and demanding experimentally,leading to high-fidelity quantum gates in a simple setup.Besides,our scheme is readily realizable in physical system currently pursued for implementation of quantum computation.Therefore,our proposal represents a promising way towards fault-tolerant geometric quantum computation.展开更多
For circuit-based quantum computation,experimental implementation of a universal set of quantum logic gates with high-fidelity and strong robustness is essential and central.Quantum gates induced by geometric phases,w...For circuit-based quantum computation,experimental implementation of a universal set of quantum logic gates with high-fidelity and strong robustness is essential and central.Quantum gates induced by geometric phases,which depend only on global properties of the evolution paths,have built-in noise-resilience features.Here,we propose and experimentally demonstrate nonadiabatic holonomic single-qubit quantum gates on two dark paths in a trapped ^(171)γδ^(+)ion based on four-level systems with resonant drives.We confirm the implementation with measured gate fidelity through both quantum process tomography and randomized benchmarking methods.Meanwhile,we find that nontrivial holonomic two-qubit quantum gates can also be realized within current experimental technologies.Compared with previous implementations,our experiments share both the advantages of fast nonadiabatic evolution and robustness against systematic errors.Therefore,our experiments confirm a promising method for fast and robust holonomic quantum computation.展开更多
Artificial intelligence has become indispensable in modern life,but its energy consumption has become a significant concern due to its huge storage and computational demands.Artificial intelligence algorithms are main...Artificial intelligence has become indispensable in modern life,but its energy consumption has become a significant concern due to its huge storage and computational demands.Artificial intelligence algorithms are mainly based on deep learning algorithms,relying on the backpropagation of convolutional neural networks or binary neural networks.While these algorithms aim to simulate the learning process of the human brain,their low bio-fidelity and the separation of storage and computing units lead to significant energy consumption.The human brain is a remarkable computing machine with extraordinary capabilities for recognizing and processing complex information while consuming very low power.Tunneling magnetoresistance(TMR)-based devices,namely magnetic tunnel junctions(MTJs),have great advantages in simulating the behavior of biological synapses and neurons.This is not only because MTJs can simulate biological behavior such as spike-timing dependence plasticity and leaky integrate-fire,but also because MTJs have intrinsic stochastic and oscillatory properties.These characteristics improve MTJs’bio-fidelity and reduce their power consumption.MTJs also possess advantages such as ultrafast dynamics and non-volatile properties,making them widely utilized in the field of neuromorphic computing in recent years.We conducted a comprehensive review of the development history and underlying principles of TMR,including a detailed introduction to the material and magnetic properties of MTJs and their temperature dependence.We also explored various writing methods of MTJs and their potential applications.Furthermore,we provided a thorough analysis of the characteristics and potential applications of different types of MTJs for neuromorphic computing.TMR-based devices have demonstrated promising potential for broad application in neuromorphic computing,particularly in the development of spiking neural networks.Their ability to perform on-chip learning with ultra-low power consumption makes them an exciting prospect for future advances in the era of the internet of things.展开更多
Challenges associated with low-drug-loading capacity,lack of active targeting of tumor cells and unspecific drug release of nanocarriers synchronously plague the success of cancer therapy.Herein,we constructed active-...Challenges associated with low-drug-loading capacity,lack of active targeting of tumor cells and unspecific drug release of nanocarriers synchronously plague the success of cancer therapy.Herein,we constructed active-targeting,redox-activated polymeric micelles(HPGssML)selfassembled aptamer-decorated,amphiphilic biodegradable poly(benzyl malolactonate-co-e-caprolactone)copolymer with disulfide linkage and p-conjugated moieties.HPGssML with a homogenous spherical shape and nanosized diameter(-150 nm)formed a low critical micellar concentration(10^-3mg/mL),suggesting good stability of polymeric micelles.The anticancer drug,doxorubicin(DOX),can be efficiently loaded into the core of micelles with high-drug-loading content via strong π-π interaction,which was verified by a decrease in fluorescence intensity and redshift in UV adsorption of DOX in micelles.The redox sensitivity of polymeric micelles was confirmed by size change and in vitro drug release in a reducing environment.Confocal microscopy and flow cytometry assay demonstrated that conjugating aptamers could enhance specific uptake of HPGssML by cancer cells.An in vitro cytotoxicity study showed that the half-maximal inhibitory concentration(IC50)of DOX-loaded HPGssML was two times lower than that of the control group,demonstrating improved antitumor efficacy.Therefore,the multifunctional biodegradable polymeric micelles can be exploited as a desirable drug carrier for effective cancer treatment.展开更多
Quantum gates,which are the essent ial building blocks of quantum computers,are very fragile.Thus,to realize robust quanturm gates with high fidelity is the ultimate goal of quantum manipulation.Here,we propose a nona...Quantum gates,which are the essent ial building blocks of quantum computers,are very fragile.Thus,to realize robust quanturm gates with high fidelity is the ultimate goal of quantum manipulation.Here,we propose a nonadiabatic geometric quantum computation scheme on superconducting circuits to engineer arbitrary quantum gates,which share both the robust merit of geometric phases and the capacity to combine with optimal control technique to further enhance the gate robustness.Specif-ically,in our proposal,arbitrary geometric single-qubit gates can be realized on a transmon qubit,by a resonant microwave field driving,with both the amplitude and phase of the driving being time-dependent.Meanwhile,nontrivial two-qubit gometric gates can be implemented by two capacitively coupled transmon qubits,with one of the transmon qubits'frequency being modulated to obtain ef-fective resonant coupling between them.Therefore,our scheme provides a promising step towards fault-tolerant solid-state quantum computation.展开更多
Chiral magnetic skyrmions are topological swirling spin textures that hold promise for future information technology. The electrical nucleation and motion of skyrmions have been experimentally demonstrated in the last...Chiral magnetic skyrmions are topological swirling spin textures that hold promise for future information technology. The electrical nucleation and motion of skyrmions have been experimentally demonstrated in the last decade, while electrical detection compatible with semiconductor processes has not been achieved, and this is considered one of the most crucial gaps regarding the use of skyrmions in real applications. Here, we report the direct observation of nanoscale skyrmions in Co Fe B/Mg O-based magnetic tunnel junction devices at room temperature. High-resolution magnetic force microscopy imaging and tunneling magnetoresistance measurements are used to illustrate the electrical detection of skyrmions,which are stabilized under the cooperation of interfacial Dzyaloshinskii–Moriya interaction, perpendicular magnetic anisotropy, and dipolar stray field. This skyrmionic magnetic tunnel junction shows a stable nonlinear multilevel resistance thanks to its topological nature and tunable density of skyrmions under current pulse excitation. These features provide important perspectives for spintronics to realize highdensity memory and neuromorphic computing.展开更多
The purpose of this study is to measure the expression of microRNA-4463 and microRNA-6087 between normal persons and patients with hepatocellular carcinoma(HCC),and to clarify the meaning of them in the prognosis eval...The purpose of this study is to measure the expression of microRNA-4463 and microRNA-6087 between normal persons and patients with hepatocellular carcinoma(HCC),and to clarify the meaning of them in the prognosis evaluation in HCC.Forty-five samples from healthy people and patients,who had been diagnosed with hepatocellular carcinoma before any treatment,were collected to study respectively.Real-time PCR was used to detect the expression of miRNA-4463 and miRNA-6087 in the serum of control group and hepatocellular carcinoma patients.The expression of miR-4463 in the serum of HCC patients was significantly higher than that in control group(P<0.05),and the expression level was independent of gender,tumor size,cell types,stages,alanine aminotransferase(ALT),aspartate aminotransferase(AST),total bilirubin(TBIL)and HBsAg status(P>0.05).But there was a significant difference of different level of AFP in HCC(P<0.05),and the difference between the group of AFP lower than 400 ug/l and the control group is statistically significant(P<0.05).Besides,the survival time had showed a significant difference at the high and low expression levels(P<0.05).But the expression level of miRNA-6087 was no difference in HCC and control group.The disorder of miRNA-4463 occurred in HCC,even the AFP level doesn’t rises.What’s more,patients who get the high level of miRNA-4463 seem to have a shorter survival time.And it contributes great to the prognostic evaluation.This is the first study to illustrate the potential significance of miRNA-4463 in the prognosis in HCC.展开更多
In this study, carbon nanotubes (CNTs) were mixed with ABs-type hydrogen storage alloy (HSA), as catalyst for an anode in a direct borohydride fuel cell (DBFC). As comparision, a series of traditional carbon mat...In this study, carbon nanotubes (CNTs) were mixed with ABs-type hydrogen storage alloy (HSA), as catalyst for an anode in a direct borohydride fuel cell (DBFC). As comparision, a series of traditional carbon materials, such as acetylene black, Vulcan XC-72R, and super activated carbon (SAC) were also employed. Electrochemical measurements showed that the electrocatalytic activity of HSA was improved greatly by CNTs. The current density of the DI3FC employing the HSA/CNTs catalytic anode could reach 1550 mA.cm-2 (at -0.6 V vs the EIg/HgO electrode) and the maximum power density of 65 mW.cm-2 for this cell could be achieved at room temperature. Furthermore, the life time test lasting for 60 h showed that the cell displayed a good stability.展开更多
Biodegradable poly(L-lactide-r-trimethene carbonate) copolymers (P(LLA-co-TMC)) with different compositions were synthesized. The degradation of the copolymers was carried out in phosphate buffer saline solutio...Biodegradable poly(L-lactide-r-trimethene carbonate) copolymers (P(LLA-co-TMC)) with different compositions were synthesized. The degradation of the copolymers was carried out in phosphate buffer saline solutions (pH = 7.4) at 37℃. The compositions, structure and properties of the copolymers in degradation were characterized with IH-NMR, DSC, XRD, GPC, and SEM. The weight loss of the P(LLA-co-TMC) 50/50 was much faster than that of P(LLA-co-TMC) 85/15 and PLLA homopolymer. Interestingly, though the molecular weight of the compolymers decreased greatly during degradation, the compositions were rarely varied. After long time degradation, the PLLA segments were induced to crystallize in the P(LLA-co-TMC) 85/15 copolymer. The SEM observation of the surface and cross-section of P(LLA-co- TMC) 85/15 copolymer films found it was similar to the bulk degradation of PLLA homopolymer.展开更多
Porous oxide ceramics are widely used in extreme working conditions owing to their excellent resistance to high temperatures and corrosion.However,sintering is an inevitable process applied to ceramics,from the green ...Porous oxide ceramics are widely used in extreme working conditions owing to their excellent resistance to high temperatures and corrosion.However,sintering is an inevitable process applied to ceramics,from the green body to the final product.The highly complex structures exacerbate the shrinkage-induced ir-regular deformation and crack formation in the sintering process.A pioneering approach is developed in this study to achieve zero shrinkage for porous alumina ceramics during multistep sintering,using a combination of active fillers-ZrAl 3 and Al 75 Si 25.The response surface method is used to optimize the material compositions and sintering process,to achieve shrinkages of less than 0.05%for the entire pro-cess.The sintering expansion mechanism is investigated by analyzing the pyrolysis and microstructures of samples at different temperatures.The combination of ZrAl 3 and Al 75 Si 25 can attain the continuous expansion of the matrix in a wide temperature range of 600-1400°C.Furthermore,typical alumina com-ponents are fabricated and used to verify the effectiveness of the proposed approach.Owing to shrinkage suppression,the profile deviation of the samples is less than 0.1 mm,and the proportion of microcracks is reduced by 97.8%.The suggested approach shows potential applications in near-net,low-defect fabrica-tion of complex fine ceramic components.展开更多
基金the financial supports of NSFC(No.20805033 and 30901199)SRF for ROCS,SEM(2008890-19-9)Doctoral Education Fund for New Teachers(200806101048)
文摘Depositing single-walled carbon nanotubes(SWNTs) with controllable density, pattern and orientation on electrodes presents a challenge in today's research. Here, we report a novel solvent evaporation method to align SWNTs in patterns having nanoscale width and micronscale length. SWNTs suspension has been introduced dropwise onto photoresist resin microchannels; and the capillary force can stretch and align SWNTs into strands with nanoscale width in the microchannels. Then these narrow and long aligned SWNTs patterns were successfully transferred to a pair of gold electrodes with different gaps to fabricate carbon nanotube field-effect transistor(CNTFET). Moreover, the electrical performance of the CNTFET show that the SWNTs strands can bridge different gaps and fabricate good electrical performance CNTFET with ON/OFF ratio around 106. This result suggests a promising and simple strategy for assembling well-aligned SWNTs into CNTFET device with good electrical performance.
基金The authors would like to express grateful acknowledgement to the support from National Natural Science Foundation of China(Nos.11802214 and 11972267)the Fundamental Research Funds for the Central Universities(WUT:2018IB006 and WUT:2019IVB042).
文摘In this work,wemodeled the brittle fracture of shell structure in the framework of Peridynamics Mindlin-Reissener shell theory,in which the shell is described by material points in themean-plane with its drilling rotation neglected in kinematic assumption.To improve the numerical accuracy,the stress-point method is utilized to eliminate the numerical instability induced by the zero-energy mode and rank-deficiency.The crack surface is represented explicitly by stress points,and a novel general crack criterion is proposed based on that.Instead of the critical stretch used in common peridynamic solid,it is convenient to describe thematerial failure by using the classic constitutive model in continuum mechanics.In this work,a concise crack simulation algorithm is also provided to describe the crack path and its development,in order to simulate the brittle fracture of the shell structure.Numerical examples are presented to validate and demonstrate our proposed model.Results reveal that our model has good accuracy and capability to represent crack propagation and branch spontaneously.
文摘Field effect transistors (FET) based on Single-Walled Carbon Nanotubes (SWNTs) become the hot topic in fields of nano-electronic, clinical diagnostics, environmental testing etc. in recent years. In this paper, we reported a simple, scalable way to enrich semiconducting SWNTs by using HNO3/H2SO4. Then carbon nanotube field-effect transistors (CNTFET) biosensor was fabricated with the enrichment SWNTs for Escherichia coli O157︰H7 detection. The response of each CNTFET was monitored in real time before and after introduction of the Escherichia coli O157︰H7 at various concentrations. The results show that CNT-FET biosensors we fabricated are sensitive to change of concentration of solution and response time is really short.
文摘Melamine formaldehyde (MF) foam is kind of fire-retardant material and has great potential in acoustic and thermal insulation area. In this article, MF resin foam was prepared by microwave radiation. We discussed the thermal stability of MF foam and the effect of different emulsifiers on its morphology, apparent density, fire-retardancy and mechanical property. The decomposition temperature of MF foam we prepared is nearly 400℃ and the constitution of residue after combustion is made up of carbon and graphite. Emulsifier influenced the apparent density of MF foam and using coemulsifiers can get flexible foam with uniform cell size, good morphology and low apparent density. When the fire-retardant MF foam’s apparent density is low of 5.53 kg/cm-3, its value of LOI can reach 32.4. The mechanical property of foam is consistent with apparent density.
基金the National Key Research and Development Program of China(No.2019YFC0408303)the Natural Science Foundation of Hunan Province,China(No.2021JJ20069)+2 种基金the Changsha Science and Technology Project,China(Nos.kq2106016,kq2009005)Higher Education Discipline Innovation Project(111 Project),China(No.B14034)the Fundamental Research Funds for the Central Universities of Central South University,China(No.2021zzts0887).
文摘The coordination structure of cupric tartrate(Cu−TA)complex was investigated by ultraviolet−visible(UV-Vis)and liquid chromatography/mass spectrometer(LC-MS)firstly;furthermore,effective coordination configurations and electronic properties of Cu−TA in aqueous solution were systematically revealed by density functional theory(DFT)calculations.Consistently,Job plots show the possible existence of[Cu(TA)]and[Cu(TA)_(2)]^(2-)at 230 and 255 nm based on UV-Vis results.LC-MS results confirm the existence of the single and high coordination complexes[Cu_(2)(TA)_(2)]^(+),[Cu(TA)_(2)]^(+)and[Cu_(2)(TA)_(3)(H_(2)O)_(2)(OH)_(2)]^(2+).DFT calculation results show that carboxylic oxygen and hydroxyl oxygen of tartaric acid(TA)are preferred sites for Cu(Ⅱ)coordination.[Cu(TA)](1H,3H sites O of TA coordinated with Cu(Ⅱ)),[Cu(TA)_(2)]^(2-)(two 1^(C),2^(H) sites O of TA coordinated with Cu(Ⅱ)),and[Cu(TA)_(3)]^(4-)(three 2H,3H sites O of TA coordinated with Cu(Ⅱ))should be dominant coordination configurations of Cu−TA.The corresponding Gibbs reaction energies are-170.1,-136.2,and-90.2 kJ/mol,respectively.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61703312 and 61703313)。
文摘The finite-time Mittag-Leffler synchronization is investigated for fractional-order delayed memristive neural networks(FDMNN)with parameters uncertainty and discontinuous activation functions.The relevant results are obtained under the framework of Filippov for such systems.Firstly,the novel feedback controller,which includes the discontinuous functions and time delays,is proposed to investigate such systems.Secondly,the conditions on finite-time Mittag-Leffler synchronization of FDMNN are established according to the properties of fractional-order calculus and inequality analysis technique.At the same time,the upper bound of the settling time for Mittag-Leffler synchronization is accurately estimated.In addition,by selecting the appropriate parameters of the designed controller and utilizing the comparison theorem for fractional-order systems,the global asymptotic synchronization is achieved as a corollary.Finally,a numerical example is given to indicate the correctness of the obtained conclusions.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11874156 and 11904111)the Project funded by China Postdoctoral Science Foundation(Grant No.2019M652684).
文摘Besides its fundamental importance, non-reciprocity has also found many potential applications in quantum technology. Recently, many quantum systems have been proposed to realize non-reciprocity, but stable non-reciprocal process is still experimentally difficult in general, due to the needed cyclical interactions in artificial systems or operational difficulties in solid state materials. Here, we propose a new kind of interaction induced non-reciprocal operation, based on the conventional stimulated-Raman-adiabatic-passage (STIRAP) setup, which removes the experimental difficulty of requiring cyclical interaction, and thus it is directly implementable in various quantum systems. Furthermore, we also illustrate our proposal on a chain of three coupled superconducting transmons, which can lead to a non-reciprocal circulator with high fidelity without a ring coupling configuration as in the previous schemes or implementations. Therefore, our protocol provides a promising way to explore fundamental non-reciprocal quantum physics as well as realize non-reciprocal quantum device.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 62176189 and 62106181)the Hubei Province Key Laboratory of Systems Science in Metallurgical Process (Wuhan University of Science and Technology) (Grant No. Y202002)。
文摘Without dividing the complex-valued systems into two real-valued ones, a class of fractional-order complex-valued memristive neural networks(FCVMNNs) with time delay is investigated. Firstly, based on the complex-valued sign function, a novel complex-valued feedback controller is devised to research such systems. Under the framework of Filippov solution, differential inclusion theory and Lyapunov stability theorem, the finite-time Mittag-Leffler synchronization(FTMLS) of FCVMNNs with time delay can be realized. Meanwhile, the upper bound of the synchronization settling time(SST) is less conservative than previous results. In addition, by adjusting controller parameters, the global asymptotic synchronization of FCVMNNs with time delay can also be realized, which improves and enrich some existing results. Lastly,some simulation examples are designed to verify the validity of conclusions.
基金Grant sponsor:National Nature Science Foundation of China,Grant number:81272960Key Research Program from Science and Technology Department of Hunan Province China,Grant number:2013WK2010 and 2014SK2015+3 种基金The fund of Tianqing liver disease researchThis work was supported by National Nature Science Foundation of China(81272960)Key Research Program from Science and Technology Department of Hunan Province,China(2013WK2010 and 2014SK2015)Key Research Program from Ministry of human Resources and Social Security of the People’s Republic of China(2016)176.
文摘Hypoxia-inducible factor(HIF)is a main heterodimeric transcription factor that regulates the cellular adaptive response to hypoxia by stimulating the transcription of a series of hypoxia-inducible genes.HIF is frequently upregulated in solid tumors,and the overexpression of HIF can promote tumor progression or aggressiveness by blood vessel architecture and altering cellular metabolism.In this review,we focused on the pivotal role of HIF in tumor angiogenesis and energy metabolism.Furthermore,we also emphasized the possibility of HIF pathway as a potential therapeutic target in cancer.
基金This work was supported by the Key R&D Program of Guangdong Province(Grant No.2018B030326001)the National Natural Science Foundation of China(Grant No.11874156)Science and Technology Program of Guangzhou(Grant No.2019050001).
文摘High-fidelity quantum gates are essential for large-scale quantum computation.However,any quantum manipulation will inevitably affected by noises,systematic errors and decoherence effects,which lead to infidelity of a target quantum task.Therefore,implementing high-fidelity,robust and fast quantum gates is highly desired.Here,we propose a fast and robust scheme to construct high-fidelity holonomic quantum gates for universal quantum computation based on resonant interaction of three-level quantum systems via shortcuts to adiabaticity.In our proposal,the target Hamiltonian to induce noncyclic non-Abelian geometric phases can be inversely engineered with less evolution time and demanding experimentally,leading to high-fidelity quantum gates in a simple setup.Besides,our scheme is readily realizable in physical system currently pursued for implementation of quantum computation.Therefore,our proposal represents a promising way towards fault-tolerant geometric quantum computation.
基金supported by the National Key Research and Development Program of China(Grants No.2017YFA0304100 and 2016YFA0302700)the National Natural Science Foundation of China(Grants No.11874343,11774335,11821404,11734015,and 11874156)+3 种基金Anhui Initiative in Quantum Information Technologies(Grants No.AHY020100 and AHY070000)Key Research Program of Frontier Sciences,CAS(Grant No.QYZDYSSW-SLH003)the Fundamental Research Funds for the Central Universities(Grant No.WK2470000026)Science and Technology Program of Guangzhou(Grant No.2019050001).
文摘For circuit-based quantum computation,experimental implementation of a universal set of quantum logic gates with high-fidelity and strong robustness is essential and central.Quantum gates induced by geometric phases,which depend only on global properties of the evolution paths,have built-in noise-resilience features.Here,we propose and experimentally demonstrate nonadiabatic holonomic single-qubit quantum gates on two dark paths in a trapped ^(171)γδ^(+)ion based on four-level systems with resonant drives.We confirm the implementation with measured gate fidelity through both quantum process tomography and randomized benchmarking methods.Meanwhile,we find that nontrivial holonomic two-qubit quantum gates can also be realized within current experimental technologies.Compared with previous implementations,our experiments share both the advantages of fast nonadiabatic evolution and robustness against systematic errors.Therefore,our experiments confirm a promising method for fast and robust holonomic quantum computation.
基金the National Key Research and Development Program of China(Grant Nos.2022YFB4400200 and 2022YFA1402604)the National Natural Science Foundation of China(Grant Nos.12104031 and 52121001)+2 种基金Science and Technology Major Project of Anhui Province(Grant No.202003a05020050)the International Collaboration Project B16001,the Beihang Hefei Innovation Research Institute Project BHKX-19-02,the China Postdoctoral Science Foundation No.2022M720345Outstanding Research Project of Shenyuan Honors College BUAA 230121102 for their financial support of this work.
文摘Artificial intelligence has become indispensable in modern life,but its energy consumption has become a significant concern due to its huge storage and computational demands.Artificial intelligence algorithms are mainly based on deep learning algorithms,relying on the backpropagation of convolutional neural networks or binary neural networks.While these algorithms aim to simulate the learning process of the human brain,their low bio-fidelity and the separation of storage and computing units lead to significant energy consumption.The human brain is a remarkable computing machine with extraordinary capabilities for recognizing and processing complex information while consuming very low power.Tunneling magnetoresistance(TMR)-based devices,namely magnetic tunnel junctions(MTJs),have great advantages in simulating the behavior of biological synapses and neurons.This is not only because MTJs can simulate biological behavior such as spike-timing dependence plasticity and leaky integrate-fire,but also because MTJs have intrinsic stochastic and oscillatory properties.These characteristics improve MTJs’bio-fidelity and reduce their power consumption.MTJs also possess advantages such as ultrafast dynamics and non-volatile properties,making them widely utilized in the field of neuromorphic computing in recent years.We conducted a comprehensive review of the development history and underlying principles of TMR,including a detailed introduction to the material and magnetic properties of MTJs and their temperature dependence.We also explored various writing methods of MTJs and their potential applications.Furthermore,we provided a thorough analysis of the characteristics and potential applications of different types of MTJs for neuromorphic computing.TMR-based devices have demonstrated promising potential for broad application in neuromorphic computing,particularly in the development of spiking neural networks.Their ability to perform on-chip learning with ultra-low power consumption makes them an exciting prospect for future advances in the era of the internet of things.
基金supported by the Natural Science Foundation of China(Grant No.51973135)National Key Research and Development Program of China(Grant Nos.2018YFC1106103,2017YFB0702600,2017YFB0702603)Science and Technology Foundation of Sichuan Province(Grant No.2018RZ0044).
文摘Challenges associated with low-drug-loading capacity,lack of active targeting of tumor cells and unspecific drug release of nanocarriers synchronously plague the success of cancer therapy.Herein,we constructed active-targeting,redox-activated polymeric micelles(HPGssML)selfassembled aptamer-decorated,amphiphilic biodegradable poly(benzyl malolactonate-co-e-caprolactone)copolymer with disulfide linkage and p-conjugated moieties.HPGssML with a homogenous spherical shape and nanosized diameter(-150 nm)formed a low critical micellar concentration(10^-3mg/mL),suggesting good stability of polymeric micelles.The anticancer drug,doxorubicin(DOX),can be efficiently loaded into the core of micelles with high-drug-loading content via strong π-π interaction,which was verified by a decrease in fluorescence intensity and redshift in UV adsorption of DOX in micelles.The redox sensitivity of polymeric micelles was confirmed by size change and in vitro drug release in a reducing environment.Confocal microscopy and flow cytometry assay demonstrated that conjugating aptamers could enhance specific uptake of HPGssML by cancer cells.An in vitro cytotoxicity study showed that the half-maximal inhibitory concentration(IC50)of DOX-loaded HPGssML was two times lower than that of the control group,demonstrating improved antitumor efficacy.Therefore,the multifunctional biodegradable polymeric micelles can be exploited as a desirable drug carrier for effective cancer treatment.
基金This work was supported by the Key-Arca Research and Development Program of Guangdong Province(Grant No.2018B030326001)the National Natural Science Foundation of China(Grant No.11874156)the National Key R&D Program of China(Grant No.2016 YFA0301803).
文摘Quantum gates,which are the essent ial building blocks of quantum computers,are very fragile.Thus,to realize robust quanturm gates with high fidelity is the ultimate goal of quantum manipulation.Here,we propose a nonadiabatic geometric quantum computation scheme on superconducting circuits to engineer arbitrary quantum gates,which share both the robust merit of geometric phases and the capacity to combine with optimal control technique to further enhance the gate robustness.Specif-ically,in our proposal,arbitrary geometric single-qubit gates can be realized on a transmon qubit,by a resonant microwave field driving,with both the amplitude and phase of the driving being time-dependent.Meanwhile,nontrivial two-qubit gometric gates can be implemented by two capacitively coupled transmon qubits,with one of the transmon qubits'frequency being modulated to obtain ef-fective resonant coupling between them.Therefore,our scheme provides a promising step towards fault-tolerant solid-state quantum computation.
基金financial support from the National Key R&D Program of China(2018YFB0407602,and 2020YFA0309300)National Natural Science Foundation of China(61627813,61871008,62001019,12004024,and 51901081)+5 种基金Beijing Natural Science Foundation(4202043)Beijing Nova Program from Beijing Municipal Science and Technology Commission(Z201100006820042)National Natural Science Foundation of China-German Research Foundation(52061135105)Outstanding Research Project of Shen Yuan Honors College,BUAA(230121102)the Science and Technology Program of Guangzhou(202002030052)Joint Research Key Fund for Guangzhou and Shen Zhen(2021B1515120047)。
文摘Chiral magnetic skyrmions are topological swirling spin textures that hold promise for future information technology. The electrical nucleation and motion of skyrmions have been experimentally demonstrated in the last decade, while electrical detection compatible with semiconductor processes has not been achieved, and this is considered one of the most crucial gaps regarding the use of skyrmions in real applications. Here, we report the direct observation of nanoscale skyrmions in Co Fe B/Mg O-based magnetic tunnel junction devices at room temperature. High-resolution magnetic force microscopy imaging and tunneling magnetoresistance measurements are used to illustrate the electrical detection of skyrmions,which are stabilized under the cooperation of interfacial Dzyaloshinskii–Moriya interaction, perpendicular magnetic anisotropy, and dipolar stray field. This skyrmionic magnetic tunnel junction shows a stable nonlinear multilevel resistance thanks to its topological nature and tunable density of skyrmions under current pulse excitation. These features provide important perspectives for spintronics to realize highdensity memory and neuromorphic computing.
基金National Nature Science Foundation of China,Grant number:81272960Key Research Program from Science and Technology Department of Hunan Province China,Grant number:2013WK2010 and 2014SK2015+1 种基金Key Research Program from Ministry of human Resources and Social Security of the People’s Republic of China,Grant number:(2016)176The fund of Tianqing liver disease research,Grant number:(TQGB20140155).
文摘The purpose of this study is to measure the expression of microRNA-4463 and microRNA-6087 between normal persons and patients with hepatocellular carcinoma(HCC),and to clarify the meaning of them in the prognosis evaluation in HCC.Forty-five samples from healthy people and patients,who had been diagnosed with hepatocellular carcinoma before any treatment,were collected to study respectively.Real-time PCR was used to detect the expression of miRNA-4463 and miRNA-6087 in the serum of control group and hepatocellular carcinoma patients.The expression of miR-4463 in the serum of HCC patients was significantly higher than that in control group(P<0.05),and the expression level was independent of gender,tumor size,cell types,stages,alanine aminotransferase(ALT),aspartate aminotransferase(AST),total bilirubin(TBIL)and HBsAg status(P>0.05).But there was a significant difference of different level of AFP in HCC(P<0.05),and the difference between the group of AFP lower than 400 ug/l and the control group is statistically significant(P<0.05).Besides,the survival time had showed a significant difference at the high and low expression levels(P<0.05).But the expression level of miRNA-6087 was no difference in HCC and control group.The disorder of miRNA-4463 occurred in HCC,even the AFP level doesn’t rises.What’s more,patients who get the high level of miRNA-4463 seem to have a shorter survival time.And it contributes great to the prognostic evaluation.This is the first study to illustrate the potential significance of miRNA-4463 in the prognosis in HCC.
文摘In this study, carbon nanotubes (CNTs) were mixed with ABs-type hydrogen storage alloy (HSA), as catalyst for an anode in a direct borohydride fuel cell (DBFC). As comparision, a series of traditional carbon materials, such as acetylene black, Vulcan XC-72R, and super activated carbon (SAC) were also employed. Electrochemical measurements showed that the electrocatalytic activity of HSA was improved greatly by CNTs. The current density of the DI3FC employing the HSA/CNTs catalytic anode could reach 1550 mA.cm-2 (at -0.6 V vs the EIg/HgO electrode) and the maximum power density of 65 mW.cm-2 for this cell could be achieved at room temperature. Furthermore, the life time test lasting for 60 h showed that the cell displayed a good stability.
基金financially supported by the National Basic Research Program of China (National 973 program,No. 2011CB606206)the National Natural Science Foundation of China (Nos. 50830105, 51133004)+1 种基金Program for New Century Excellent Talents in Universities, Ministry of Education (MOE, NCET-10-0564)Program for Changjiang Scholars and Innovative Research Teams in Universities (IRT1163)
文摘Biodegradable poly(L-lactide-r-trimethene carbonate) copolymers (P(LLA-co-TMC)) with different compositions were synthesized. The degradation of the copolymers was carried out in phosphate buffer saline solutions (pH = 7.4) at 37℃. The compositions, structure and properties of the copolymers in degradation were characterized with IH-NMR, DSC, XRD, GPC, and SEM. The weight loss of the P(LLA-co-TMC) 50/50 was much faster than that of P(LLA-co-TMC) 85/15 and PLLA homopolymer. Interestingly, though the molecular weight of the compolymers decreased greatly during degradation, the compositions were rarely varied. After long time degradation, the PLLA segments were induced to crystallize in the P(LLA-co-TMC) 85/15 copolymer. The SEM observation of the surface and cross-section of P(LLA-co- TMC) 85/15 copolymer films found it was similar to the bulk degradation of PLLA homopolymer.
基金the National Natural Science Foun-dation of China(No.52005392)the National Science and Tech-nology Major Project(No.J2019-Ⅶ−0013-0153)the Fundamental Research Funds for the Central Universities,and the Youth Innova-tion Team of Shaanxi Universities.
文摘Porous oxide ceramics are widely used in extreme working conditions owing to their excellent resistance to high temperatures and corrosion.However,sintering is an inevitable process applied to ceramics,from the green body to the final product.The highly complex structures exacerbate the shrinkage-induced ir-regular deformation and crack formation in the sintering process.A pioneering approach is developed in this study to achieve zero shrinkage for porous alumina ceramics during multistep sintering,using a combination of active fillers-ZrAl 3 and Al 75 Si 25.The response surface method is used to optimize the material compositions and sintering process,to achieve shrinkages of less than 0.05%for the entire pro-cess.The sintering expansion mechanism is investigated by analyzing the pyrolysis and microstructures of samples at different temperatures.The combination of ZrAl 3 and Al 75 Si 25 can attain the continuous expansion of the matrix in a wide temperature range of 600-1400°C.Furthermore,typical alumina com-ponents are fabricated and used to verify the effectiveness of the proposed approach.Owing to shrinkage suppression,the profile deviation of the samples is less than 0.1 mm,and the proportion of microcracks is reduced by 97.8%.The suggested approach shows potential applications in near-net,low-defect fabrica-tion of complex fine ceramic components.