The conversion of CO_(2) into specific aromatics by modulating the morphology of zeolites is a promising strategy.HZSM-5 zeolite with hollow tubular morphology is reported.The morphology of zeolite was precisely contr...The conversion of CO_(2) into specific aromatics by modulating the morphology of zeolites is a promising strategy.HZSM-5 zeolite with hollow tubular morphology is reported.The morphology of zeolite was precisely controlled,and the acid sites on its outer surface were passivated by steam-assisted crystallization method,so that the zeolite exhibits higher aromatic selectivity than sheet HZSM-5 zeolite and greater p-xylene selectivity than chain HZSM-5 zeolite.The tandem catalyst was formed by combining hollow tubular HZSM-5 zeolites with ZnZrO_(x)metal oxides.The para-selectivity of p-xylene reached 76.2%at reaction temperature of 320℃,pressure of 3.0 MPa,and a flow rate of 2400 mL g^(-1)h^(-1)with an H_(2)/CO_(2) molar ratio of 3/1.Further research indicates that the high selectivity of p-xylene is due to the pore structure of hollow tubular HZSM-5 zeolite,which is conducive to the formation of p-xylene.Moreover,the passivation of the acid site located on the outer surface of zeolite effectively prevents the isomerization of p-xylene.The reaction mechanism of CO_(2) hydrogenation over the tandem catalyst was investigated using in-situ diffuse reflectance Fourier transform infrared spectroscopy and density functional theory.The results showed that the CO_(2) to p-xylene followed a methanol-mediated route over ZnZrO_(x)/hollow tubular HZSM-5 tandem catalysts.In addition,the catalyst showed no significant deactivation in the 100 h stability test.This present study provides an effective strategy for the design of catalysts aimed at selectively preparing aromatics through CO_(2)hydrogenation.展开更多
In order to improve the energy efficiency(EE)in cognitive radio(CR),this paper investigates the joint design of cooperative spectrum sensing time and the power control optimization problem for the secondary user syste...In order to improve the energy efficiency(EE)in cognitive radio(CR),this paper investigates the joint design of cooperative spectrum sensing time and the power control optimization problem for the secondary user systems to achieve the maximum energy efficiency in a cognitive network based on hybrid spectrum sharing,meanwhile considering the maximum transmit power,user quality of service(QoS)requirements,interference limitations,and primary user protection.The optimization of energy efficient sensing time and power allocation is formulated as a non-convex optimization problem.The Dinkelbach’s method is adopted to solve this problem and to transform the non-convex optimization problem in fractional form into an equivalent optimization problem in the form of subtraction.Then,an iterative power allocation algorithm is proposed to solve the optimization problem.The simulation results show the effectiveness of the proposed algorithms for energy-efficient resource allocation in the cognitive network.展开更多
We have systematically studied the thermoelectric properties in Zn-doped Sn Te.Strikingly,band convergence and embedded precipitates arising from Zn doping,can trigger a prominent improvement of thermoelectric perform...We have systematically studied the thermoelectric properties in Zn-doped Sn Te.Strikingly,band convergence and embedded precipitates arising from Zn doping,can trigger a prominent improvement of thermoelectric performance.In particular,the value of dimensionless figure of merit z T has increased by 100% and up to ~ 0.5 at 775 K for the optimal sample with 2% Zn content.Present findings demonstrate that carrier concentration and effective mass play crucial roles on the Seebeck coefficient and power factor.The obvious deviation from the Pisarenko line(Seebeck coefficient versus carrier concentration) due to Zn-doping reveals the convergence of valence bands.When the doping concentration exceeds the solubility,precipitates occur and lead to a reduction of lattice thermal conductivity.In addition,bipolar conduction is suppressed,indicating an enlargement of band gap.The Zn-doped Sn Te is shown to be a promising candidate for thermoelectric applications.展开更多
Artificial nest boxes are placed to attract birds to nest and breed in a specific location,and they are widely used in avian ecology research and in the attraction of insectivorous birds.There is evidence that artific...Artificial nest boxes are placed to attract birds to nest and breed in a specific location,and they are widely used in avian ecology research and in the attraction of insectivorous birds.There is evidence that artificial nest boxes can adversely affect breeding fitness but no great focus has been placed on this issue by researchers.Therefore,we retrieved 321 research papers regarding artificial nest boxes published from 2003 to 2022 and used the'Biblioshiny'program to extract and integrate keywords;we then summarized the adverse effects of artificial nest boxes on avian breeding success.The studies highlighted many drawbacks and misuses in the designing and placement of nest boxes;furthermore,bird attraction was decreased by their inappropriate selection,thus reducing breeding success.Regarding nest box production,there were shortcomings in the construction material,color,smell,and structural design of the boxes used.Nest boxes were also placed at inappropriate densities,locations,orientations,heights,and managed incorrectly.Finally,we propose suggestions for more efficient and safer artificial nest boxes for future use in avian ecology research and bird conservation.展开更多
5G has pushed the use of radio spectrum to a new level,and cognitive clustering network can effectively improve the utilization of radio spectrum,which is a feasible way to solve the growing demand for wireless commun...5G has pushed the use of radio spectrum to a new level,and cognitive clustering network can effectively improve the utilization of radio spectrum,which is a feasible way to solve the growing demand for wireless communications.However,cognitive clustering network is vulnerable to PUEA attack,which will lead to the degradation of system detection performance,thereby reducing the energy efficiency.Aiming at these problems,this paper investigates the optimal energy efficiency resource allocation scheme for cognitive clustering network under PUEA attack.A cooperative user selection algorithm based on selection factor is proposed to effectively resist PUEA user attack and improve detection performance.We construct the energy efficiency optimization problem under multi-constraint conditions and transform the nonlinear programming problem into parametric programming problem,which is solved by Lagrangian function and Karush-Kuhn-Tucker condition.Then the sub-gradient iterative algorithm based on optimal energy efficiency under PUEA attack is proposed and its complexity is analyzed.Simulation results indicate that proposed method is effective when subjected to PUEA attacks,and the impact of different parameters on energy efficiency is analyzed.展开更多
Objective:Paclitaxel(P)is a standard second-line chemotherapy in the treatment of advanced gastric cancer.This study compared the clinical outcome of a paclitaxel plus raltitrexed(RP)regimen as second-line treatment i...Objective:Paclitaxel(P)is a standard second-line chemotherapy in the treatment of advanced gastric cancer.This study compared the clinical outcome of a paclitaxel plus raltitrexed(RP)regimen as second-line treatment in metastatic gastric cancer(MGC)patients.Methods:An open,randomized,multi-center phase Ⅱ clinical trial was conducted involving 148 patients who were randomly assigned and treated with RP[raltitrexed(3 mg/m^(2)on day 1)and paclitaxel(135 mg/m^(2)on day 1 every 3 weeks)]or P[paclitaxel(135 mg/m^(2)on day 1 every 3 weeks)]as 2nd-line chemotherapy.The primary endpoint was progression-free survival(PFS).The secondary endpoints were the overall response rate(ORR),overall survival(OS),and safety.Results:PFS had a tendency to be prolonged with RP compared to P(2.7 months vs.1.7 months;P=0.148).OS was also prolonged with RP compared to P(10.2 months vs.6.1 months;P=0.140).The ORR was equal in the RP and P groups(6.8%and 4.0%;P=0.72).The disease control rate(DCR)in the RP and P groups was 56.2%and 36.0%,respectively.Grade 3-4 treatment-related adverse events occurred in 36.2%(RP)and 28.2%(P)of patients.Frequent grade 3-4 toxicities for RP and P were neutropenia(11.0%and 4.0%),anemia(1.4%and 4.0%),and thrombocytopenia(1.4%and 5.3%),and all grades of peripheral neurotoxicity(12.3%vs.17.3%).All grades of hepatic toxicity were demonstrated for the RP and P groups based on elevated aminotransferase levels(27.4%and 14.1%).Subgroup analysis shows if MGC was combined with ascites or peritoneal involvement,the OS of the RP regimen was longer(P=0.05).Conclusions:Second-line palliative chemotherapy with RP was shown to prolong the PFS and OS,especially among patients with ascites or peritoneal involvement,which warrants confirmation using larger sample studies.展开更多
The growing awareness of climate change worldwide has led the urban tourism market to focus on balancing tourist tailored experiences and CO_(2) emissions.Therefore,designing personalized tourist routes with environ‐...The growing awareness of climate change worldwide has led the urban tourism market to focus on balancing tourist tailored experiences and CO_(2) emissions.Therefore,designing personalized tourist routes with environ‐mental pollution consideration is preferable in this context.This study proposes an evolution algorithm based on reinforcement learning(FSRL-HA)to design a personalized day tour route that simultaneously considers the utility of tourists and the carbon emission.We conducted a case study in Chengdu,Sichuan,China,to evaluate this algorithm's performance.The results indicate that the proposed algorithm outperforms selected baseline methods.Furthermore,the approach can provide more diverse route choices for different tourists,and an experiment was conducted to explore how tourist preferences affect tourist utilities.展开更多
The simulation on pyrolysis products of pure PF resin with different chemical structure was investigated and validated by pyrolysis gas-chromatography mass spectrometry(Py-GC/MS).The simulation of pyrolysis products o...The simulation on pyrolysis products of pure PF resin with different chemical structure was investigated and validated by pyrolysis gas-chromatography mass spectrometry(Py-GC/MS).The simulation of pyrolysis products of phenolic resin with different chemical structure was investigated by AMBER(Assisted Model Building with Energy Refinement)force field.The content of pyrolysis products phenol and cresol decreases with the increase of F/P(formaldehyde/phenol)value.The content of pyrolysis products dimethylphenol and trimethylphenol increases with the enhancement of F/P value.The crosslink density of phenolic mixture can be measured by the content of pyrolysis products dimethylphenol and trimethylphenol.Consequently,the results of simulation were validated by the Py-GC/MS experiment.展开更多
Lipid metabolism play an essential role in occurrence and development of asthma,and it can be disturbed by phthalate esters(PAEs)and organophosphate fame retardants(OPFRs).As a chronic infammatory respiratory disease,...Lipid metabolism play an essential role in occurrence and development of asthma,and it can be disturbed by phthalate esters(PAEs)and organophosphate fame retardants(OPFRs).As a chronic infammatory respiratory disease,the occurrence risk of childhood asthma is increased by PAEs and OPFRs exposure,but it remains not entirely clear how PAEs and OPFRs contribute the onset and progress of the disease.We have profiled the serum levels of PAEs and OPFRs congeners by liquid chromatography coupled with mass spectrometry,and its relationships with the dysregulation of lipid metabolism in asthmatic,bronchitic(acute infammation)and healthy(non-infammation)children.Eight PAEs and nine OPFRs congeners were found in the serum of children(1–5 years old)from Shenzhen,and their total median levels were 615.16 ng/m L and 17.06 ng/m L,respectively.Moreover,the serum levels of mono-methyl phthalate(MMP),tri-propyl phosphate(TPP)and tri-n-butyl phosphate(TNBP)were significant higher in asthmatic children than in healthy and bronchitic children as control.Thirty-one characteristic lipids and fatty acids of asthma were screened by machine-learning random forest model based on serum lipidome data,and the alterations of infammatory characteristic lipids and fatty acids including palmitic acids,12,13-Di HODE,14,21-Di HDHA,prostaglandin D2 and Lyso PA(18:2)showed significant correlated with high serum levels of MMP,TPP and TNBP.These results imply PAEs and OPFRs promote the occurrence of childhood asthma via disrupting infammatory lipid and fatty acid metabolism,and provide a novel sight for better understanding the effects of plastic additives on childhood asthma.展开更多
Preterm birth(PTB)is a leading cause of neonatal morbidity and mortality worldwide,yet the cellular and molecular mechanisms driving this condition remain undeciphered,thus limiting discovery of new therapies.In-depth...Preterm birth(PTB)is a leading cause of neonatal morbidity and mortality worldwide,yet the cellular and molecular mechanisms driving this condition remain undeciphered,thus limiting discovery of new therapies.In-depth analyses of human and mouse tissues associated with PTB,in combination with cellular studies,indicated that aberrantly high-expressed neutrophil cytoplasmic factor(NCF)1 leads to oxidative distress,recruitment,and pro-inflammatory activation of neutrophils and macrophages,while sequentially overexpressed pro-inflammatory mediators induce contractions of uterine smooth muscle cells(USMCs)as well as apoptosis of USMCs and amniotic epithelial cells,thereby causing PTB.According to these new findings,we rationally engineered an amphiphilic macromolecular conjugate LPA by covalently integrating low-molecular-weight heparin,a reactive oxygen species-responsive/scavenging component,and an anti-inflammatory peptide.This bioengineered macromolecular conjugate can selfassemble into multi-bioactive nanoparticles(LPA NP).In a mouse model of PTB,LPA NP effectively delayed PTB and inhibited adverse pregnancy outcomes,by regulating NCF1-mediated oxidativeinflammatory cascades,i.e.,attenuating oxidative stress,inhibiting inflammatory cell activation,reducing local inflammation,and decreasing contraction/apoptosis of myometrial cells.Packaging LPA NP into temperature-responsive,self-healing,and bioadhesive hydrogel further potentiated its in vivo efficacies after intravaginal delivery,by prolonging retention time,sustaining nanotherapy release,and increasing bioavailability in the placenta/uterus.Importantly,both the conjugate/nanotherapy and hydrogel formulations exhibited excellent safety profiles in pregnant mice,with negligible side effects on the mother and offspring.展开更多
The investigation concentrates on friction stir welded(FSW)Al-Cu-Li alloy concerning its local microstructural evolution and mechanical properties.The grain features were characterized by electron back scattered diffr...The investigation concentrates on friction stir welded(FSW)Al-Cu-Li alloy concerning its local microstructural evolution and mechanical properties.The grain features were characterized by electron back scattered diffraction(EBSD)technology,while precipitate characterization was conducted by using transmission electron microscopy(TEM)aligned along[011]Al and[001]Al zone axes.The mechanical properties are evaluated through micro-hardness and tensile testing.It can be found that nugget zones exhibit finely equiaxed grains evolved through complete dynamic recrystallization(DRX),primarily occurring in continuous dynamic recrystallization(CDRX)and discontinuous dynamic recrystallization(DDRX).In the thermal-mechanically affected zone(TMAZ),numerous sub-structured grains,exhibiting an elongated morphology,were created due to partial DRX,signifying the dominance of CDRX,DDRX,and geometric dynamic recrystallization(GDRX)in this region.T_(1)completely dissolves in the nugget zone(NZ)leading to the formation of Guinier-Preston zones and increase ofδ′,β′and S′.Conversely,T_(1)partially solubilizes in TMAZ,the lowest hardness zone(LHZ)and heat affected zone(HAZ),and the residual T_(1)undergoes marked coarsening,revealing various T_(1)variants.The solubilization and coarsening of T_(1)are primary contributors to the degradation of hardness and strength.θ′primarily dissolves and coarsens in NZ and TMAZ,whilst this precipitate largely coarsens in HAZ and LHZ.σ,TB,grain boundary phases(GBPs)and precipitate-free zone(PFZ)are newly generated during FSW.σexists in the TMAZ,LHZ and HAZ,whereas TB nucleates in NZ.GBPs and PFZ mostly develop in LHZ and HAZ,which can cause strain localization during tensile deformation,potentially leading to LHZ joint fracture.展开更多
MicroRNAs(miRNAs)and small interfering RNAs(siRNAs)regulate gene expression in eukaryotes.Plant miRNAs modulate their targets mainly via messenger RNA(mRNA)cleavage.Small RNA(sRNA)targets have been extensively investi...MicroRNAs(miRNAs)and small interfering RNAs(siRNAs)regulate gene expression in eukaryotes.Plant miRNAs modulate their targets mainly via messenger RNA(mRNA)cleavage.Small RNA(sRNA)targets have been extensively investigated in Arabidopsis using computational prediction,experimental validation,and degradome sequencing.However,small RNA targets are largely unknown in rice(Oryza sativa).Here,we report global identification of small RNA targets using high throughput degradome sequencing in the rice indica cultivar 93-11(Oryza sativa L.ssp.indica).One hundred and seventy-seven transcripts targeted by a total of 87 unique miRNAs were identified.Of targets for the conserved miRNAs between Arabidopsis and rice,transcription factors comprise around 70%(58 in 82),indicating that these miRNAs act as masters of gene regulatory nodes in rice.In contrast,non-conserved miRNAs targeted diverse genes which provide more complex regulatory networks.In addition,5 AUXIN RESPONSE FACTORs(ARFs)cleaved by the TAS3 derived ta-siRNAs were also detected.A total of 40 sRNA targets were further validated via RNA ligasemediated 5′rapid amplification of cDNA ends(RLM 5′-RACE).Our degradome results present a detailed sRNAtarget interaction atlas,which provides a guide for the study of the roles of sRNAs and their targets in rice.展开更多
Early distinction of bipolar disorder(BD)from major depressive disorder(MDD)is difficult since no tools are available to estimate the risk of BD.In this study,we aimed to develop and validate a model of oxidative stre...Early distinction of bipolar disorder(BD)from major depressive disorder(MDD)is difficult since no tools are available to estimate the risk of BD.In this study,we aimed to develop and validate a model of oxidative stress injury for predicting BD.Data were collected from 1252 BD and 1359 MDD patients,including 64 MDD patients identified as converting to BD from 2009 through 2018.30 variables from a randomly-selected subsample of 1827(70%)patients were used to develop the model,including age,sex,oxidative stress markers(uric acid,bilirubin,albumin,and prealbumin),sex hormones,cytokines,thyroid and liver function,and glycolipid metabolism.Univariate analyses and the Least Absolute Shrinkage and Selection Operator were applied for data dimension reduction and variable selection.Multivariable logistic regression was used to construct a model for predicting bipolar disorder by oxidative stress biomarkers(BIOS)on a nomogram.Internal validation was assessed in the remaining 784 patients(30%),and independent external validation was done with data from 3797 matched patients from five other hospitals in China.10 predictors,mainly oxidative stress markers,were shown on the nomogram.The BIOS model showed good discrimination in the training sample,with an AUC of 75.1%(95%CI:72.9%–77.3%),sensitivity of 0.66,and specificity of 0.73.The discrimination was good both in internal validation(AUC 72.1%,68.6%–75.6%)and external validation(AUC 65.7%,63.9%–67.5%).In this study,we developed a nomogram centered on oxidative stress injury,which could help in the individualized prediction of BD.For better real-world practice,a set of measurements,especially on oxidative stress markers,should be emphasized using big data in psychiatry.展开更多
Growth and health responses of pigs fed fermented liquid diet are not always consistent and causes for this issue are still not very clear. Metabolites produced at different fermentation time points should be one of t...Growth and health responses of pigs fed fermented liquid diet are not always consistent and causes for this issue are still not very clear. Metabolites produced at different fermentation time points should be one of the most important contributors. However, currently no literatures about differential metabolites of fermented liquid diet are reported. The aim of this experiment was to explore the difference of metabolites in a fermented liquid diet between different fermentation time intervals. A total of eighteen samples that collected from Bacillus subtilis fermented liquid diet on days 7, 21 and 35 respectively were used for the identification of metabolites by gas chromatography time of flight mass spectrometry(GCTOF-MS). Fifteen differential metabolites including melibiose, sortitol, ribose, cellobiose, maltotriose,sorbose, iso maltose, maltose, fructose, D-glycerol-1-phosphate, 4-aminobutyric acid, beta-alanine, tyrosine, pyruvic acid and pantothenic acid were identified between 7-d samples and 21-d samples. The relative level of melibiose, ribose, maltotriose, D-glycerol-1-phosphate, tyrosine and pyruvic acid in samples collected on day 21 was significantly higher than that in samples collected on day 7(P < 0.01),respectively. Eight differential metabolites including ribose, sorbose, galactinol, cellobiose, pyruvic acid,galactonic acid, pantothenic acid and guanosine were found between 21-d samples and 35-d samples.Samples collected on day 35 had a higher relative level of ribose than that in samples collected on day 21(P < 0.01), In conclusion, many differential metabolites which have important effects on the growth and health of pigs are identified and findings contribute to explain the difference in feeding response of fermented liquid diet.展开更多
We propose the configuration of signal multiplexing with four polarization states and investigate its transmission performance over single-mode fiber links.Using coherent detection and digital signal processing,a demo...We propose the configuration of signal multiplexing with four polarization states and investigate its transmission performance over single-mode fiber links.Using coherent detection and digital signal processing,a demodulation scheme for four-polarization-multiplexed(4PM)system is presented.We discuss the impact of crosstalk from polarization mode dispersion and polarization beam splitter misalignment on the proposed 4PM system.Furthermore,the transmission distance could be doubled to*50 km by employing feedback decision equalizers.展开更多
Mass detection of glucose,which is required in many applications,remains challenging.The commercial enzyme-based glucose test strips cannot be reused,and current non-enzymatic glucose sensors exhibit a narrow range of...Mass detection of glucose,which is required in many applications,remains challenging.The commercial enzyme-based glucose test strips cannot be reused,and current non-enzymatic glucose sensors exhibit a narrow range of detection and slow glucose oxidation kinetics.Herein,controlled etching of Prussian blue analogue(PBA)nanocubes at the vertices is conducted and Au nanoparticles(Au NPs)are subsequently inlaid in the etched cavities by in-situ reduction of HAuCl4.The unique AuNP-PBA nanocomplexes exhibit low electrochemical potential for glucose oxidation,high electrocatalytic activity,and rapid redox electron transfer rate.Covalent immobilization of the Au-inlaid nanomaterials on a fine Au wire leads to a non-enzymatic glucose sensor with a particularly wide linear detection range(10μM to 16 mM),excellent anti-interference,and fast response.More importantly,the sensor is reusable,and its sensitivity is well maintained even after 150 times of detection.This new-concept material promises to enable high-throughput glucose detection at a low cost,which is essential in diabetic management and other healthcare applications.展开更多
Nicotine ingested from smoking exerts neuroprotection and developmental neurotoxicity in central nervous system.It can produce several changes of cognitive behaviors through regulating the release of different neurotr...Nicotine ingested from smoking exerts neuroprotection and developmental neurotoxicity in central nervous system.It can produce several changes of cognitive behaviors through regulating the release of different neurotransmitters in the brain.However,the effects of nicotine exposure or withdrawal on neurotransmitter metabolism of hippocampus are still unclear.In this study,we real-time evaluated the dynamic alterations in neurotransmitter metabolism of hippocampal neuronal(HT22)cells induced by nicotine exposure and withdrawal at relevant exposure levels of smoking and secondhand smoke by using a microfluidic chip-coupled with liquid chromatography-mass spectrometry(MC-LC-MS)system.We found HT22 cells mainly released related neurotransmitters of tryptophan and choline metabolism,both nicotine exposure and withdraw altered its neurotransmitters and their metabolites release.Exposure to nicotine mainly altered the secretion of serotonin,kynurenic acid,choline and acetylcholine of HT22 cells to improve hippocampal dependent cognition,and the change are closely related to the dose and duration of exposure.Moreover,the altered metabolites could rapidly recover after nicotine withdrawal,but picolinic acid was elevated.MC-LC-MS system used in present study showed a greater advantage to detect unstable metabolites than conventional method by using in vitro model,and the results of dynamic alterations of neurotransmitter metabolism induced by nicotine might provide a potential targets for drug development of neuroprotection or cognitive improvement.展开更多
The discovery of band convergence has opened an effective avenue for significantly enhancing thermoelectric performance of SnTe,while alloying CdTe in SnTe is evidenced efficient for improving the valley degeneracy.Ho...The discovery of band convergence has opened an effective avenue for significantly enhancing thermoelectric performance of SnTe,while alloying CdTe in SnTe is evidenced efficient for improving the valley degeneracy.However,the thermoelectric transport properties are limited due to the low solubility of CdTe in SnTe(~3%).Inspired by the improvement of dimensionless figure of merit zT in Cu or Se-doped SnTe,investigating the effect of Cu_(2)Se on the electronic and phonon transport properties of SnTe-CdTe alloys is highly desired.Traditionally,improving the quality factor can trigger an increase of the potential of a compound for higher zT,which is of importance for design of thermoelectric materials.Here,alloyed 3%Cu_(2)Se in SnTe-3%CdTe system enables an increased peak zT,which is attributed by the optimization of electronic performance(~21μW cm^(-1)K^(-2)at 800 K),as well as the decreased lattice thermal conductivity owing to the enhanced mass and strain fluctuations.More importantly,alloying Cu_(2)Se not only improves the quality factor from~0.25 to~0.45,resulting in a higher maximum potential zT,but also effectively preserves the Fermi energy in a relative optimized level.The current findings demonstrate the role of Cu_(2)Se for manipulating thermoelectrics in SnTe.展开更多
We experimentally demonstrated the use of intelligent impairment equalization(IIE)for microwave downconversion link linearization in noncooperative systems.Such an equalizer is realized based on an artificial neural n...We experimentally demonstrated the use of intelligent impairment equalization(IIE)for microwave downconversion link linearization in noncooperative systems.Such an equalizer is realized based on an artificial neural network(ANN).Once the training process is completed,the inverse link transfer function can be determined.With the inverse transformation for the detected signal after transmission,the third-order intermodulation distortion components are suppressed significantly without requiring any prior information from an input RF signal.Furthermore,fast training speed is achieved,since the configuration of ANN-based equalizer is simple.Experimental results show that the spurious-free dynamic range of the proposed link is improved to 106.5 dB·Hz^(2/3),which is 11.3 dB higher than that of a link without IIE.Meanwhile,the training epochs reduce to only five,which has the potential to meet the practical engineering requirement.展开更多
基金financially supported by the National Natural Science Foundation of China(22268039)the Natural Science Foundation for Distinguished Young Scholars of Gansu Province(23JRRA682)。
文摘The conversion of CO_(2) into specific aromatics by modulating the morphology of zeolites is a promising strategy.HZSM-5 zeolite with hollow tubular morphology is reported.The morphology of zeolite was precisely controlled,and the acid sites on its outer surface were passivated by steam-assisted crystallization method,so that the zeolite exhibits higher aromatic selectivity than sheet HZSM-5 zeolite and greater p-xylene selectivity than chain HZSM-5 zeolite.The tandem catalyst was formed by combining hollow tubular HZSM-5 zeolites with ZnZrO_(x)metal oxides.The para-selectivity of p-xylene reached 76.2%at reaction temperature of 320℃,pressure of 3.0 MPa,and a flow rate of 2400 mL g^(-1)h^(-1)with an H_(2)/CO_(2) molar ratio of 3/1.Further research indicates that the high selectivity of p-xylene is due to the pore structure of hollow tubular HZSM-5 zeolite,which is conducive to the formation of p-xylene.Moreover,the passivation of the acid site located on the outer surface of zeolite effectively prevents the isomerization of p-xylene.The reaction mechanism of CO_(2) hydrogenation over the tandem catalyst was investigated using in-situ diffuse reflectance Fourier transform infrared spectroscopy and density functional theory.The results showed that the CO_(2) to p-xylene followed a methanol-mediated route over ZnZrO_(x)/hollow tubular HZSM-5 tandem catalysts.In addition,the catalyst showed no significant deactivation in the 100 h stability test.This present study provides an effective strategy for the design of catalysts aimed at selectively preparing aromatics through CO_(2)hydrogenation.
基金supported in part by the National Natural Science Foundation of China for Young Scholars under Grant No.61701167Young Elite Backbone Teachers in Blue and Blue Project of Jiangsu Province, China
文摘In order to improve the energy efficiency(EE)in cognitive radio(CR),this paper investigates the joint design of cooperative spectrum sensing time and the power control optimization problem for the secondary user systems to achieve the maximum energy efficiency in a cognitive network based on hybrid spectrum sharing,meanwhile considering the maximum transmit power,user quality of service(QoS)requirements,interference limitations,and primary user protection.The optimization of energy efficient sensing time and power allocation is formulated as a non-convex optimization problem.The Dinkelbach’s method is adopted to solve this problem and to transform the non-convex optimization problem in fractional form into an equivalent optimization problem in the form of subtraction.Then,an iterative power allocation algorithm is proposed to solve the optimization problem.The simulation results show the effectiveness of the proposed algorithms for energy-efficient resource allocation in the cognitive network.
基金Project supported by the National Natural Science Foundation of China(Grant No.51771126)the Youth Foundation of Science&Technology Department of Sichuan Province,China(Grant No.2016JQ0051)+3 种基金the Sichuan University Talent Introduction Research Funding(Grand No.YJ201537)the Sichuan University Outstanding Young Scholars Research Funding(Grant No.2015SCU04A20)the World First-Class University Construction Fundingthe Fundamental and Frontier Research in Chongqing(Grant No.CSTC2015JCYJBX0026)
文摘We have systematically studied the thermoelectric properties in Zn-doped Sn Te.Strikingly,band convergence and embedded precipitates arising from Zn doping,can trigger a prominent improvement of thermoelectric performance.In particular,the value of dimensionless figure of merit z T has increased by 100% and up to ~ 0.5 at 775 K for the optimal sample with 2% Zn content.Present findings demonstrate that carrier concentration and effective mass play crucial roles on the Seebeck coefficient and power factor.The obvious deviation from the Pisarenko line(Seebeck coefficient versus carrier concentration) due to Zn-doping reveals the convergence of valence bands.When the doping concentration exceeds the solubility,precipitates occur and lead to a reduction of lattice thermal conductivity.In addition,bipolar conduction is suppressed,indicating an enlargement of band gap.The Zn-doped Sn Te is shown to be a promising candidate for thermoelectric applications.
基金supported by the National Natural Science Foundation of China(Grant No.32170485,31501867)the Fundamental Research Funds for the Central Universities(Grant No.2572022BE02)。
文摘Artificial nest boxes are placed to attract birds to nest and breed in a specific location,and they are widely used in avian ecology research and in the attraction of insectivorous birds.There is evidence that artificial nest boxes can adversely affect breeding fitness but no great focus has been placed on this issue by researchers.Therefore,we retrieved 321 research papers regarding artificial nest boxes published from 2003 to 2022 and used the'Biblioshiny'program to extract and integrate keywords;we then summarized the adverse effects of artificial nest boxes on avian breeding success.The studies highlighted many drawbacks and misuses in the designing and placement of nest boxes;furthermore,bird attraction was decreased by their inappropriate selection,thus reducing breeding success.Regarding nest box production,there were shortcomings in the construction material,color,smell,and structural design of the boxes used.Nest boxes were also placed at inappropriate densities,locations,orientations,heights,and managed incorrectly.Finally,we propose suggestions for more efficient and safer artificial nest boxes for future use in avian ecology research and bird conservation.
基金by the National Natural Science Foundation of China for Young Scholars under Grant No.61701167.
文摘5G has pushed the use of radio spectrum to a new level,and cognitive clustering network can effectively improve the utilization of radio spectrum,which is a feasible way to solve the growing demand for wireless communications.However,cognitive clustering network is vulnerable to PUEA attack,which will lead to the degradation of system detection performance,thereby reducing the energy efficiency.Aiming at these problems,this paper investigates the optimal energy efficiency resource allocation scheme for cognitive clustering network under PUEA attack.A cooperative user selection algorithm based on selection factor is proposed to effectively resist PUEA user attack and improve detection performance.We construct the energy efficiency optimization problem under multi-constraint conditions and transform the nonlinear programming problem into parametric programming problem,which is solved by Lagrangian function and Karush-Kuhn-Tucker condition.Then the sub-gradient iterative algorithm based on optimal energy efficiency under PUEA attack is proposed and its complexity is analyzed.Simulation results indicate that proposed method is effective when subjected to PUEA attacks,and the impact of different parameters on energy efficiency is analyzed.
文摘Objective:Paclitaxel(P)is a standard second-line chemotherapy in the treatment of advanced gastric cancer.This study compared the clinical outcome of a paclitaxel plus raltitrexed(RP)regimen as second-line treatment in metastatic gastric cancer(MGC)patients.Methods:An open,randomized,multi-center phase Ⅱ clinical trial was conducted involving 148 patients who were randomly assigned and treated with RP[raltitrexed(3 mg/m^(2)on day 1)and paclitaxel(135 mg/m^(2)on day 1 every 3 weeks)]or P[paclitaxel(135 mg/m^(2)on day 1 every 3 weeks)]as 2nd-line chemotherapy.The primary endpoint was progression-free survival(PFS).The secondary endpoints were the overall response rate(ORR),overall survival(OS),and safety.Results:PFS had a tendency to be prolonged with RP compared to P(2.7 months vs.1.7 months;P=0.148).OS was also prolonged with RP compared to P(10.2 months vs.6.1 months;P=0.140).The ORR was equal in the RP and P groups(6.8%and 4.0%;P=0.72).The disease control rate(DCR)in the RP and P groups was 56.2%and 36.0%,respectively.Grade 3-4 treatment-related adverse events occurred in 36.2%(RP)and 28.2%(P)of patients.Frequent grade 3-4 toxicities for RP and P were neutropenia(11.0%and 4.0%),anemia(1.4%and 4.0%),and thrombocytopenia(1.4%and 5.3%),and all grades of peripheral neurotoxicity(12.3%vs.17.3%).All grades of hepatic toxicity were demonstrated for the RP and P groups based on elevated aminotransferase levels(27.4%and 14.1%).Subgroup analysis shows if MGC was combined with ascites or peritoneal involvement,the OS of the RP regimen was longer(P=0.05).Conclusions:Second-line palliative chemotherapy with RP was shown to prolong the PFS and OS,especially among patients with ascites or peritoneal involvement,which warrants confirmation using larger sample studies.
基金We acknowledge the financial support from the National Natural Science Foundation of China[Grant number:71701167]the Humani‐ties and Social Science Foundation of Chinese Ministry of Education[Grant number:17YJC630078].
文摘The growing awareness of climate change worldwide has led the urban tourism market to focus on balancing tourist tailored experiences and CO_(2) emissions.Therefore,designing personalized tourist routes with environ‐mental pollution consideration is preferable in this context.This study proposes an evolution algorithm based on reinforcement learning(FSRL-HA)to design a personalized day tour route that simultaneously considers the utility of tourists and the carbon emission.We conducted a case study in Chengdu,Sichuan,China,to evaluate this algorithm's performance.The results indicate that the proposed algorithm outperforms selected baseline methods.Furthermore,the approach can provide more diverse route choices for different tourists,and an experiment was conducted to explore how tourist preferences affect tourist utilities.
文摘The simulation on pyrolysis products of pure PF resin with different chemical structure was investigated and validated by pyrolysis gas-chromatography mass spectrometry(Py-GC/MS).The simulation of pyrolysis products of phenolic resin with different chemical structure was investigated by AMBER(Assisted Model Building with Energy Refinement)force field.The content of pyrolysis products phenol and cresol decreases with the increase of F/P(formaldehyde/phenol)value.The content of pyrolysis products dimethylphenol and trimethylphenol increases with the enhancement of F/P value.The crosslink density of phenolic mixture can be measured by the content of pyrolysis products dimethylphenol and trimethylphenol.Consequently,the results of simulation were validated by the Py-GC/MS experiment.
基金supported by the National Natural Science Foundation of China (Nos.22076197,21707149 and 82127801)the Scientific Instrument Developing Project of the Chinese Academy of Sciences (No.YJKYYQ20200034)+1 种基金Shenzhen Science and Technology Research Funding (Nos.JCYJ20210324115811031 and JCYJ20200109115405930)Guangdong Basic and Applied Basic Research Foundation (No.2020B1515120080)。
文摘Lipid metabolism play an essential role in occurrence and development of asthma,and it can be disturbed by phthalate esters(PAEs)and organophosphate fame retardants(OPFRs).As a chronic infammatory respiratory disease,the occurrence risk of childhood asthma is increased by PAEs and OPFRs exposure,but it remains not entirely clear how PAEs and OPFRs contribute the onset and progress of the disease.We have profiled the serum levels of PAEs and OPFRs congeners by liquid chromatography coupled with mass spectrometry,and its relationships with the dysregulation of lipid metabolism in asthmatic,bronchitic(acute infammation)and healthy(non-infammation)children.Eight PAEs and nine OPFRs congeners were found in the serum of children(1–5 years old)from Shenzhen,and their total median levels were 615.16 ng/m L and 17.06 ng/m L,respectively.Moreover,the serum levels of mono-methyl phthalate(MMP),tri-propyl phosphate(TPP)and tri-n-butyl phosphate(TNBP)were significant higher in asthmatic children than in healthy and bronchitic children as control.Thirty-one characteristic lipids and fatty acids of asthma were screened by machine-learning random forest model based on serum lipidome data,and the alterations of infammatory characteristic lipids and fatty acids including palmitic acids,12,13-Di HODE,14,21-Di HDHA,prostaglandin D2 and Lyso PA(18:2)showed significant correlated with high serum levels of MMP,TPP and TNBP.These results imply PAEs and OPFRs promote the occurrence of childhood asthma via disrupting infammatory lipid and fatty acid metabolism,and provide a novel sight for better understanding the effects of plastic additives on childhood asthma.
基金supported by the National Natural Science Foundation of China(82301918)Joint Funds of the National Natural Science Foundation of China(U21A20346)+3 种基金the Natural Science Foundation of Chongqing(CSTB2022NSCQ-MSX0856)the Key Program for Technological Innovation&Application Development of Chongqing(CSTB2022TIAD-KPX0156)the Key Medical Program Integrated by Chongqing Science and Technology Bureau and Chongqing Health Commission(2023GGXM005)the Program for Scientific and Technological Innovation Leader of Chongqing(CQYC20210302362).
文摘Preterm birth(PTB)is a leading cause of neonatal morbidity and mortality worldwide,yet the cellular and molecular mechanisms driving this condition remain undeciphered,thus limiting discovery of new therapies.In-depth analyses of human and mouse tissues associated with PTB,in combination with cellular studies,indicated that aberrantly high-expressed neutrophil cytoplasmic factor(NCF)1 leads to oxidative distress,recruitment,and pro-inflammatory activation of neutrophils and macrophages,while sequentially overexpressed pro-inflammatory mediators induce contractions of uterine smooth muscle cells(USMCs)as well as apoptosis of USMCs and amniotic epithelial cells,thereby causing PTB.According to these new findings,we rationally engineered an amphiphilic macromolecular conjugate LPA by covalently integrating low-molecular-weight heparin,a reactive oxygen species-responsive/scavenging component,and an anti-inflammatory peptide.This bioengineered macromolecular conjugate can selfassemble into multi-bioactive nanoparticles(LPA NP).In a mouse model of PTB,LPA NP effectively delayed PTB and inhibited adverse pregnancy outcomes,by regulating NCF1-mediated oxidativeinflammatory cascades,i.e.,attenuating oxidative stress,inhibiting inflammatory cell activation,reducing local inflammation,and decreasing contraction/apoptosis of myometrial cells.Packaging LPA NP into temperature-responsive,self-healing,and bioadhesive hydrogel further potentiated its in vivo efficacies after intravaginal delivery,by prolonging retention time,sustaining nanotherapy release,and increasing bioavailability in the placenta/uterus.Importantly,both the conjugate/nanotherapy and hydrogel formulations exhibited excellent safety profiles in pregnant mice,with negligible side effects on the mother and offspring.
基金financially supported by the Natural Science Foundation of Sichuan Province(2023NSFSC0915)the Postdoctoral Research Project Special Fund of Sichuan Province and Natural Science Starting Project of SWPU(2023QHZ017).
文摘The investigation concentrates on friction stir welded(FSW)Al-Cu-Li alloy concerning its local microstructural evolution and mechanical properties.The grain features were characterized by electron back scattered diffraction(EBSD)technology,while precipitate characterization was conducted by using transmission electron microscopy(TEM)aligned along[011]Al and[001]Al zone axes.The mechanical properties are evaluated through micro-hardness and tensile testing.It can be found that nugget zones exhibit finely equiaxed grains evolved through complete dynamic recrystallization(DRX),primarily occurring in continuous dynamic recrystallization(CDRX)and discontinuous dynamic recrystallization(DDRX).In the thermal-mechanically affected zone(TMAZ),numerous sub-structured grains,exhibiting an elongated morphology,were created due to partial DRX,signifying the dominance of CDRX,DDRX,and geometric dynamic recrystallization(GDRX)in this region.T_(1)completely dissolves in the nugget zone(NZ)leading to the formation of Guinier-Preston zones and increase ofδ′,β′and S′.Conversely,T_(1)partially solubilizes in TMAZ,the lowest hardness zone(LHZ)and heat affected zone(HAZ),and the residual T_(1)undergoes marked coarsening,revealing various T_(1)variants.The solubilization and coarsening of T_(1)are primary contributors to the degradation of hardness and strength.θ′primarily dissolves and coarsens in NZ and TMAZ,whilst this precipitate largely coarsens in HAZ and LHZ.σ,TB,grain boundary phases(GBPs)and precipitate-free zone(PFZ)are newly generated during FSW.σexists in the TMAZ,LHZ and HAZ,whereas TB nucleates in NZ.GBPs and PFZ mostly develop in LHZ and HAZ,which can cause strain localization during tensile deformation,potentially leading to LHZ joint fracture.
基金This work was supported by National Basic Research Program of China(Nos.2009CB941500 and 2005CB522400 to X.C.)by National Natural Science Foundation of China(Grant Nos.30870534 and 30621001 to X.C.).
文摘MicroRNAs(miRNAs)and small interfering RNAs(siRNAs)regulate gene expression in eukaryotes.Plant miRNAs modulate their targets mainly via messenger RNA(mRNA)cleavage.Small RNA(sRNA)targets have been extensively investigated in Arabidopsis using computational prediction,experimental validation,and degradome sequencing.However,small RNA targets are largely unknown in rice(Oryza sativa).Here,we report global identification of small RNA targets using high throughput degradome sequencing in the rice indica cultivar 93-11(Oryza sativa L.ssp.indica).One hundred and seventy-seven transcripts targeted by a total of 87 unique miRNAs were identified.Of targets for the conserved miRNAs between Arabidopsis and rice,transcription factors comprise around 70%(58 in 82),indicating that these miRNAs act as masters of gene regulatory nodes in rice.In contrast,non-conserved miRNAs targeted diverse genes which provide more complex regulatory networks.In addition,5 AUXIN RESPONSE FACTORs(ARFs)cleaved by the TAS3 derived ta-siRNAs were also detected.A total of 40 sRNA targets were further validated via RNA ligasemediated 5′rapid amplification of cDNA ends(RLM 5′-RACE).Our degradome results present a detailed sRNAtarget interaction atlas,which provides a guide for the study of the roles of sRNAs and their targets in rice.
基金supported by the National Key Research and Development Program of China(2016YFC1307100)the National Natural Science Foundation of China(81930033,81771465,and 91232719)+3 种基金the Shanghai Mental Health Centre Clinical Research Center Special Project for Big Data Analysis(CRC2018DSJ01-1)Shanghai Municipal Science and Technology Major Project(2018SHZDZX05)Scientific Research Project of Hongkou District Health Commission(2101-03)Shanghai Clinical Research Center for Mental Health(SCRC-MH and 19MC1911100)。
文摘Early distinction of bipolar disorder(BD)from major depressive disorder(MDD)is difficult since no tools are available to estimate the risk of BD.In this study,we aimed to develop and validate a model of oxidative stress injury for predicting BD.Data were collected from 1252 BD and 1359 MDD patients,including 64 MDD patients identified as converting to BD from 2009 through 2018.30 variables from a randomly-selected subsample of 1827(70%)patients were used to develop the model,including age,sex,oxidative stress markers(uric acid,bilirubin,albumin,and prealbumin),sex hormones,cytokines,thyroid and liver function,and glycolipid metabolism.Univariate analyses and the Least Absolute Shrinkage and Selection Operator were applied for data dimension reduction and variable selection.Multivariable logistic regression was used to construct a model for predicting bipolar disorder by oxidative stress biomarkers(BIOS)on a nomogram.Internal validation was assessed in the remaining 784 patients(30%),and independent external validation was done with data from 3797 matched patients from five other hospitals in China.10 predictors,mainly oxidative stress markers,were shown on the nomogram.The BIOS model showed good discrimination in the training sample,with an AUC of 75.1%(95%CI:72.9%–77.3%),sensitivity of 0.66,and specificity of 0.73.The discrimination was good both in internal validation(AUC 72.1%,68.6%–75.6%)and external validation(AUC 65.7%,63.9%–67.5%).In this study,we developed a nomogram centered on oxidative stress injury,which could help in the individualized prediction of BD.For better real-world practice,a set of measurements,especially on oxidative stress markers,should be emphasized using big data in psychiatry.
基金supported by Jiangxi Provincial Key Technology R&D Program (20121BBF60032 and 20132BBF60039)
文摘Growth and health responses of pigs fed fermented liquid diet are not always consistent and causes for this issue are still not very clear. Metabolites produced at different fermentation time points should be one of the most important contributors. However, currently no literatures about differential metabolites of fermented liquid diet are reported. The aim of this experiment was to explore the difference of metabolites in a fermented liquid diet between different fermentation time intervals. A total of eighteen samples that collected from Bacillus subtilis fermented liquid diet on days 7, 21 and 35 respectively were used for the identification of metabolites by gas chromatography time of flight mass spectrometry(GCTOF-MS). Fifteen differential metabolites including melibiose, sortitol, ribose, cellobiose, maltotriose,sorbose, iso maltose, maltose, fructose, D-glycerol-1-phosphate, 4-aminobutyric acid, beta-alanine, tyrosine, pyruvic acid and pantothenic acid were identified between 7-d samples and 21-d samples. The relative level of melibiose, ribose, maltotriose, D-glycerol-1-phosphate, tyrosine and pyruvic acid in samples collected on day 21 was significantly higher than that in samples collected on day 7(P < 0.01),respectively. Eight differential metabolites including ribose, sorbose, galactinol, cellobiose, pyruvic acid,galactonic acid, pantothenic acid and guanosine were found between 21-d samples and 35-d samples.Samples collected on day 35 had a higher relative level of ribose than that in samples collected on day 21(P < 0.01), In conclusion, many differential metabolites which have important effects on the growth and health of pigs are identified and findings contribute to explain the difference in feeding response of fermented liquid diet.
基金supported by the National Basic Research Program of China(‘‘973’’Program)(2012CB315704)the National Natural Science Foundation of China(61275068,61111140390)
文摘We propose the configuration of signal multiplexing with four polarization states and investigate its transmission performance over single-mode fiber links.Using coherent detection and digital signal processing,a demodulation scheme for four-polarization-multiplexed(4PM)system is presented.We discuss the impact of crosstalk from polarization mode dispersion and polarization beam splitter misalignment on the proposed 4PM system.Furthermore,the transmission distance could be doubled to*50 km by employing feedback decision equalizers.
基金supported by the National Key Research and Development Program of China(No.2018YFC1106802)the Postdoctoral Interdisciplinary Research Fund in Sichuan University(No.0900904153016).
文摘Mass detection of glucose,which is required in many applications,remains challenging.The commercial enzyme-based glucose test strips cannot be reused,and current non-enzymatic glucose sensors exhibit a narrow range of detection and slow glucose oxidation kinetics.Herein,controlled etching of Prussian blue analogue(PBA)nanocubes at the vertices is conducted and Au nanoparticles(Au NPs)are subsequently inlaid in the etched cavities by in-situ reduction of HAuCl4.The unique AuNP-PBA nanocomplexes exhibit low electrochemical potential for glucose oxidation,high electrocatalytic activity,and rapid redox electron transfer rate.Covalent immobilization of the Au-inlaid nanomaterials on a fine Au wire leads to a non-enzymatic glucose sensor with a particularly wide linear detection range(10μM to 16 mM),excellent anti-interference,and fast response.More importantly,the sensor is reusable,and its sensitivity is well maintained even after 150 times of detection.This new-concept material promises to enable high-throughput glucose detection at a low cost,which is essential in diabetic management and other healthcare applications.
基金the National Natural Science Foundation of China(No.22076197)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(No.YJKYYQ20200034)+2 种基金Shenzhen Engineering Laboratory of Single-molecule Detection and Instrument Development(No.XMHT20190204002)Shenzhen Science and Technology Innovation Commission(No.JCYJ20200109115405930)Basic and Applied Basic Research Foundation of Guangdong Province(No.2020B1515120080)。
文摘Nicotine ingested from smoking exerts neuroprotection and developmental neurotoxicity in central nervous system.It can produce several changes of cognitive behaviors through regulating the release of different neurotransmitters in the brain.However,the effects of nicotine exposure or withdrawal on neurotransmitter metabolism of hippocampus are still unclear.In this study,we real-time evaluated the dynamic alterations in neurotransmitter metabolism of hippocampal neuronal(HT22)cells induced by nicotine exposure and withdrawal at relevant exposure levels of smoking and secondhand smoke by using a microfluidic chip-coupled with liquid chromatography-mass spectrometry(MC-LC-MS)system.We found HT22 cells mainly released related neurotransmitters of tryptophan and choline metabolism,both nicotine exposure and withdraw altered its neurotransmitters and their metabolites release.Exposure to nicotine mainly altered the secretion of serotonin,kynurenic acid,choline and acetylcholine of HT22 cells to improve hippocampal dependent cognition,and the change are closely related to the dose and duration of exposure.Moreover,the altered metabolites could rapidly recover after nicotine withdrawal,but picolinic acid was elevated.MC-LC-MS system used in present study showed a greater advantage to detect unstable metabolites than conventional method by using in vitro model,and the results of dynamic alterations of neurotransmitter metabolism induced by nicotine might provide a potential targets for drug development of neuroprotection or cognitive improvement.
基金financially supported by the National Key Research and Development Program of China(Grant No.2018YFA0702100)the Joint Funds of the National Natural Science Foundation(NNSF)of China+4 种基金the Chinese Academy of Sciences’Large-Scale Scientific Facility(Grant No.U1932106)the NNSF of China(Grant No.51771126)the Nuclear Power Technology Innovation Center(NPTIC)of China(Grant No.HG2020065)Sichuan University Innovation Research Program of China(Grant No.2020SCUNL112)the World First-Class University Construction Funding of China。
文摘The discovery of band convergence has opened an effective avenue for significantly enhancing thermoelectric performance of SnTe,while alloying CdTe in SnTe is evidenced efficient for improving the valley degeneracy.However,the thermoelectric transport properties are limited due to the low solubility of CdTe in SnTe(~3%).Inspired by the improvement of dimensionless figure of merit zT in Cu or Se-doped SnTe,investigating the effect of Cu_(2)Se on the electronic and phonon transport properties of SnTe-CdTe alloys is highly desired.Traditionally,improving the quality factor can trigger an increase of the potential of a compound for higher zT,which is of importance for design of thermoelectric materials.Here,alloyed 3%Cu_(2)Se in SnTe-3%CdTe system enables an increased peak zT,which is attributed by the optimization of electronic performance(~21μW cm^(-1)K^(-2)at 800 K),as well as the decreased lattice thermal conductivity owing to the enhanced mass and strain fluctuations.More importantly,alloying Cu_(2)Se not only improves the quality factor from~0.25 to~0.45,resulting in a higher maximum potential zT,but also effectively preserves the Fermi energy in a relative optimized level.The current findings demonstrate the role of Cu_(2)Se for manipulating thermoelectrics in SnTe.
基金supported in part by the National Key Research and Development Program of China(No.2018YFB2201702)the National Natural Science Foundation of China(Nos.U21A20507 and 62005228)the Fundamental Research Funds for the Central Universities(No.2682021CX050)。
文摘We experimentally demonstrated the use of intelligent impairment equalization(IIE)for microwave downconversion link linearization in noncooperative systems.Such an equalizer is realized based on an artificial neural network(ANN).Once the training process is completed,the inverse link transfer function can be determined.With the inverse transformation for the detected signal after transmission,the third-order intermodulation distortion components are suppressed significantly without requiring any prior information from an input RF signal.Furthermore,fast training speed is achieved,since the configuration of ANN-based equalizer is simple.Experimental results show that the spurious-free dynamic range of the proposed link is improved to 106.5 dB·Hz^(2/3),which is 11.3 dB higher than that of a link without IIE.Meanwhile,the training epochs reduce to only five,which has the potential to meet the practical engineering requirement.