Investigated the properties of LUCas sequence(LUC), the paper proposed a new variant of (probabilistic) public-key encryption scheme. Security analysis of the proposed encryption schemes shows that its one-wayness is ...Investigated the properties of LUCas sequence(LUC), the paper proposed a new variant of (probabilistic) public-key encryption scheme. Security analysis of the proposed encryption schemes shows that its one-wayness is equivalent to partial LUC discrete logarithm problem in ZN, and for the proposed probabilistic encryption scheme, its semantic security is equivalent to decisional LUC Diffie-Hellman problem in ZN. At last, the efficiency of the proposed schemes is briefly analyzed.展开更多
To design a Banyan network with an arbitrary even-sized port number, the PN2I network is proposed. The PN2I network can be divided into two classes: the complete and incomplete versions. A simple routing algorithm is ...To design a Banyan network with an arbitrary even-sized port number, the PN2I network is proposed. The PN2I network can be divided into two classes: the complete and incomplete versions. A simple routing algorithm is given, but in the incomplete PN2I networks,this routing algorithm fails to make the traffic in links even, which deteriorates the performance badly. Thus a new routing algorithm is proposed, which makes the incomplete PN2I networks behave almost the same as the PN2I networks with respect to the performance issues.展开更多
M50 steel,commonly utilized in aircraft engine bearings,is susceptible to friction-induced failures,particularly in high-temperature service conditions.To address this issue,various strategies have been proposed,with ...M50 steel,commonly utilized in aircraft engine bearings,is susceptible to friction-induced failures,particularly in high-temperature service conditions.To address this issue,various strategies have been proposed,with laser shock peening(LSP)garnering significant attention due to its deeper residual stress penetration and excellent surface integrity,whereas the underlying strengthening mechanisms have not yet been fully elucidated.In this study,we systematically investigate the impact of LSP treatment on the tribological properties of M50 steel at temperatures of 25 and 300℃,alongside elucidating the relevant micro-mechanisms.Microstructural analysis reveals that laser impact strengthening primarily arises from dislocation proliferation,resulting in a surface hardness increase of approximately 14%and the formation of a substantial compressive stress layer reaching a maximum value of about 1200 MPa,with a depth of around 2 mm.Friction test results demonstrate reduced coefficients of friction and wear rates following LSP treatment at both temperatures.Notably,a more pronounced reduction is observed at 300℃,with values decreasing by 41.4%and 55.8%,respectively.The enhanced performance is attributed to the synergistic interplay of compressive residual stresses,work-hardening layers,increased density of dislocations,and substantial microstructure refinement.展开更多
Melon fruit flavor is a key quality characteristic that influences consumer preference.Grafting is an effective technique to enhance fruit quality but yields divergent outcomes in terms of fruit flavor.To address this...Melon fruit flavor is a key quality characteristic that influences consumer preference.Grafting is an effective technique to enhance fruit quality but yields divergent outcomes in terms of fruit flavor.To address this problem,we analyzed parallel changes in flavor-related metabolite accumulation and gene expression in two pumpkin rootstock grafted melons during four fruit developmental stages.We identified 26061 expressed genes and 840 metabolites from 21 different compound classes,including carbohydrates,amino acids,and lipids.We also detected 50 aroma volatile compounds in the grafted melons.Results showed that genes and metabolites associated with metabolic pathways(carbohydrate,amino acid,lipid,and phenylpropanoid)play a key role in flavor formation.Compared with‘Sizhuang 12’,‘Tianzhen 1’rootstock improved melon fruit flavor by upregulating sugar-related genes(HK,MPI,MIOX,and STP)and inducing metabolite accumulation(d-ribose-5-phosphate,d-galactose,and trehalose 6-phosphate),whereas decreasing bitterness-related amino acids(l-arginine,l-asparagine,and l-tyrosine)and associated genes(thrC,ACS,and GLUL)expression at ripening stage.Furthermore,‘Tianzhen 1’exhibited higher expression levels of enzyme-coding genes(4CL,CSE,and COMT)responsible for aroma volatile synthesis than‘Sizhuang 12’rootstock.Taken together,our results decipher the basis of the molecular mechanism underlying fruit flavor in grafted melons and provide valuable information for the melons genetic improvement.展开更多
In GNSS denied environments,pseudolites have to rely on prior information,such as ground anchoring points,terrain matching or other multi-source means for positioning.This paper proposes a method of dynamic networking...In GNSS denied environments,pseudolites have to rely on prior information,such as ground anchoring points,terrain matching or other multi-source means for positioning.This paper proposes a method of dynamic networking of UAVs pseudolites for accurate navigation with only inertial navigation during GNSS denied area,which can provide accurate positioning services without prior information like anchor points.On this basis,this paper proposes a mathematical model of UAV pseudolite networking to describe the relationship of UAV flight altitude,network service coverage and anti-jamming capabilities.This model demonstrates excellent anti-interference ability,which can achieve a maximum power enhancement of up to 54.58 dB.And it can also offer another operating mode with a maximum coverage range of up to 2675.47 km^(2),while still ensuring a power enhancement of 37.57dB.This method can effectively solve the problem of providing continuous positioning services as an alternative GNSS,and is also a powerful support solution for resilient Positioning,Navigation,and Timing(PNT)^([1]).展开更多
Robustness against measurement uncertainties is crucial for gas turbine engine diagnosis.While current research focuses mainly on measurement noise,measurement bias remains challenging.This study proposes a novel perf...Robustness against measurement uncertainties is crucial for gas turbine engine diagnosis.While current research focuses mainly on measurement noise,measurement bias remains challenging.This study proposes a novel performance-based fault detection and identification(FDI)strategy for twin-shaft turbofan gas turbine engines and addresses these uncertainties through a first-order Takagi-Sugeno-Kang fuzzy inference system.To handle ambient condition changes,we use parameter correction to preprocess the raw measurement data,which reduces the FDI’s system complexity.Additionally,the power-level angle is set as a scheduling parameter to reduce the number of rules in the TSK-based FDI system.The data for designing,training,and testing the proposed FDI strategy are generated using a component-level turbofan engine model.The antecedent and consequent parameters of the TSK-based FDI system are optimized using the particle swarm optimization algorithm and ridge regression.A robust structure combining a specialized fuzzy inference system with the TSK-based FDI system is proposed to handle measurement biases.The performance of the first-order TSK-based FDI system and robust FDI structure are evaluated through comprehensive simulation studies.Comparative studies confirm the superior accuracy of the first-order TSK-based FDI system in fault detection,isolation,and identification.The robust structure demonstrates a 2%-8%improvement in the success rate index under relatively large measurement bias conditions,thereby indicating excellent robustness.Accuracy against significant bias values and computation time are also evaluated,suggesting that the proposed robust structure has desirable online performance.This study proposes a novel FDI strategy that effectively addresses measurement uncertainties.展开更多
Blade Tip Timing(BTT)enables non-contact measurements of rotating blades by placing probes strategically.Due to the uneven probe layout,BTT signals exhibit periodic irregularities.While recovering parameters like freq...Blade Tip Timing(BTT)enables non-contact measurements of rotating blades by placing probes strategically.Due to the uneven probe layout,BTT signals exhibit periodic irregularities.While recovering parameters like frequency from such signals is possible,achieving high-precision vibration parameters remains challenging.This paper proposed a novel two-stage off-grid estimation method.It leverages a unique array layout(coprime array)to obtain a regular augmented covariance matrix.Subsequently,parameters in the matrix are recovered using the sparse iterative covariance-based estimation method based on covariance fitting criteria.Finally,high-precision estimates of imprecise parameters are obtained using unconditional maximum likelihood estimation,effectively eliminating the effects of basis mismatch.Through substantial numerical and experimental validation,the proposed method demonstrates significantly higher accuracy compared to classical BTT parameter estimation methods,approaching the lower bound of unbiased estimation variance.Furthermore,due to its immunity to frequency gridding,it can track minor frequency deviations,making it more suitable for indicating blade condition.展开更多
Covert communication guarantees the security of wireless communications via hiding the existence of the transmission.This paper focuses on the first and second order asymptotics of covert communication in the AWGN cha...Covert communication guarantees the security of wireless communications via hiding the existence of the transmission.This paper focuses on the first and second order asymptotics of covert communication in the AWGN channels.The covertness is measured by the total variation distance between the channel output distributions induced with and without the transmission.We provide the exact expressions of the maximum amount of information that can be transmitted with the maximum error probability and the total variation less than any small numbers.The energy detection and the random coding are employed to prove our results.We further compare our results with those under relative entropy.The results show how many additional amounts of information can be transmitted covertly when changing the covertness constraint to total variation.展开更多
When immersed in sand and dust environment,aero-engine blades are exposed to harsh erosion which may lead to failure if erosion is severe.Using Physical Vapor Deposition(PVD)to prepare hard ceramic coatings can greatl...When immersed in sand and dust environment,aero-engine blades are exposed to harsh erosion which may lead to failure if erosion is severe.Using Physical Vapor Deposition(PVD)to prepare hard ceramic coatings can greatly enhance the operational capabilities of aero-engine.However,due to the“line-of-sight”processing characteristic of PVD process,uneven coating deposition rates occur when preparing coatings on obstructed areas such as blisks.Quantitative research on such phenomena is few,and it is even rarer in the study of aero-engine coatings.Based on the analyses and considerations of the geometric shape of blade surfaces and the influence of both deposition and re-sputtering effect,an ideal model is established to analyze the deposition rate variation along blocked region in complex self-shadowing boundaries.The relative deposition rates at various locations on the blade surface within the inter-blade gaps are quantitatively calculated and experimentally validated.Furthermore,differences in erosion resistance of the coatings are tested.The conclusions are drawn as follows:the geometric configuration of the obstructed shape and resputtering phenomenon significantly influence the deposition rates within the inner wall of blade gaps.Taking the structural configuration as an example,in a 25 mm×60 mm×15 mm gap,the coating thickness can vary more than 252%from the thickest to the thinnest location.The deposition rates of various locations are proportional to the solid angle of incident ion in more obstructed regions,and the re-sputtering is more prominent in open regions.Obstructive boundaries directly affect the erosion resistance at various locations within the gaps,with erosion failure time decreasing by 40%in heavily blocked region compared to open region.展开更多
Plasma-assisted combustion technology has been a hot spot in aero-engines andscramjet-engines.The electron density is a key discharge parameter related to the active-particledensity.The latter has been considered play...Plasma-assisted combustion technology has been a hot spot in aero-engines andscramjet-engines.The electron density is a key discharge parameter related to the active-particledensity.The latter has been considered playing an important role in the above applications bythe kinetic effect.In this work,an atmospheric pressure air plasma collisional-radiative model con-sidering the excited states of atomic nitrogen and oxygen is built based on previous widely kineticinvestigations of molecules and radicals,as well as their excited states.The excited states,especiallythe atomic nitrogen and oxygen states were less investigated in previous works.The emission inten-sity distributions from the model have a good agreement with those measured in the glide arcplasma with two discharge modes,as well as the microwave plasma.Based on the kinetics of molec-ular and atomic emitting states,the line-ratio method is presented to determine the electron density.The N_(2)(337 nm)/O(844 nm)and N_(2)(337 nm)/NO(γ)line ratios are used for the glide arc plasma andmicrowave plasma torch,respectively.Besides,the kinetics of the excited states involved with twoline-ratios are also investigated in the two types of discharges.Combined with the atmospheric pres-sure actinometry method,the kinetic effect of the plasma-assisted combustion can be revealed quan-titatively in the future.展开更多
The durability of dental implant carrier coatings is of paramount importance for the expeditious and predictable osseointegration process.The present work is based on a bionic micro/nano hierarchy struc-ture,which con...The durability of dental implant carrier coatings is of paramount importance for the expeditious and predictable osseointegration process.The present work is based on a bionic micro/nano hierarchy struc-ture,which consists of titanium surface microstructures and their internal TiO2 nanotubes(TNTs)with drug-carrying capacity.This effectively increases the wear resistance of the drug-carrying coating on the titanium surface.In comparison to untextured samples,the wear volume and wear depth of the optimal texture group are markedly diminished,resulting in a significant enhancement of wear resistance.This improvement was primarily attributed to the smaller contact area of the microstructure.Concurrently,the microstructure serves to safeguard the TNTs from damage during friction.The hydrophilic biomimetic anti-wear micro/nano hierarchies demonstrated the capacity to promote MC3T3-E1 cell adhesion and pro-liferation,while also exhibiting no cytotoxic effects.Moreover,the micro/nano hierarchical structure can be directly applied to the surface of commercialized implants.In simulated clinical conditions,the im-plant was inserted into a fresh Bama porcine mandible,and the structure of the drug-loading coatings remained intact.This structure enhances the abrasion resistance of the drug coating while minimizing alterations to the original treatment process of the implant,which is of great significance in the clinical application of implant-loaded drug delivery.展开更多
Melon(Cucumis melo L.)is a globally important fruit crop appreciated for its sweet taste,unique aroma,and nutritional value(Kaleem et al.,2024).Aroma,shaped by volatile organic compounds(VOCs),is a key trait influenci...Melon(Cucumis melo L.)is a globally important fruit crop appreciated for its sweet taste,unique aroma,and nutritional value(Kaleem et al.,2024).Aroma,shaped by volatile organic compounds(VOCs),is a key trait influencing consumer preference.These VOCs are mainly derived from amino acids,fatty acids,and terpenoid pathways(Chen et al.,2023).Esters contribute to fruity and sweet notes,whereas terpenes and C_(9) aldehydes/alcohols impart floral and melon-like aromas,respectively(Mayobre et al.,2024).展开更多
In this study,the efects of defect,mean stress and lower loading are investigated for high cycle(HCF)and very high cycle fatigue(VHCF)behavior of Ti-6Al-4V alloy.It indicates that the S-N curve of Ti-6Al-4V alloy exhi...In this study,the efects of defect,mean stress and lower loading are investigated for high cycle(HCF)and very high cycle fatigue(VHCF)behavior of Ti-6Al-4V alloy.It indicates that the S-N curve of Ti-6Al-4V alloy exhibits a linear decreasing trend or a plateau characteristic in HCF and VHCF regimes,which depends on the defect size and stress ratio.VHCF strength decreases with increasing the defect size,and it is irrespective of stress ratios.The fatigue crack initiates from specimen surface at R=−1 in both HCF and VHCF regimes.While the fatigue crack initiates from the subsurface or the interior of the specimen at R=0.1 in VHCF regime.A sequence of lower stress amplitude below the fatigue strength at 10^(9) cyc has no or negligible infuence on the fatigue life of 10^(5)-10^(9) cyc.The lower stress amplitude in variable amplitude loadings does not afect the failure mechanism.The residual compressive stress relaxation is not observed after a large number of lower loadings under ultrasonic frequency fatigue test.Gerber formula and Goodman formula give dangerous predictions of VHCF strength for both smooth specimens and specimens with defects.展开更多
GeTe-based alloys are promising thermoelectric materials for use at medium temperatures owing to their excellent thermoelectric performance.In this study,Ge_(0.8-x)Mn_(0.1)Pb_(0.1)Sb_(x)Te alloys were obtained via vac...GeTe-based alloys are promising thermoelectric materials for use at medium temperatures owing to their excellent thermoelectric performance.In this study,Ge_(0.8-x)Mn_(0.1)Pb_(0.1)Sb_(x)Te alloys were obtained via vacuum melting and hot-press sintering.Sb doping effectively decreased the carrier concentration,resulting in an enhancement of the Seebeck coefficient and consequently imparting excellent electrical transport performance to the sample.With doping concentration increasing,the structure of the sample changed from rhombohedral to cubic,creating a more favorable band structure for electronic transport properties.The incorporation of Sb into GeTe intensifies the lattice defects within the material.The significant decrease in the lattice thermal conductivity of the Ge_(0.71)Mn_(0.1)Pb_(0.1)Sb_(0.09)Te alloy to 0.84 W m^(-1)K^(-1)at 323 K is primarily attributed to the phonon scattering effect emanating from the presence of edge dislocation,point defects,and inherent grain boundaries.Finally,the maximum ZT value of the Ge_(0.74)Mn_(0.1)Pb_(0.1)Sb_(0.06)Te alloy was~1.53773 K,which is a significant enhancement of 0.35 compared to the undoped Ge_(0.8)Mn_(0.1)Pb_(0.1)Te alloy.This substantial improvement underscores the positive impact of the selected doping elements and their concentrations on the overall thermoelectric performance of the alloy.展开更多
MYB-type transcription factors contain the conserved MYB DNA-binding domain of approximately 50 amino acids and are involved in the regulation of many aspects of plant growth, development, metabolism and stress respon...MYB-type transcription factors contain the conserved MYB DNA-binding domain of approximately 50 amino acids and are involved in the regulation of many aspects of plant growth, development, metabolism and stress responses. From soybean plants, we identified 156 GmMYB genes using our previously obtained 206 MYB unigenes, and 48 were found to have full-length open-reading frames. Expressions of all these identified genes were examined, and we found that expressions of 43 genes were changed upon treatment with ABA, salt, drought and/or cold stress. Three GmMYB genes, GmMYB76, GmMYB92 and GmMYB177, were chosen for further analysis. Using the yeast assay system, GmMYB76 and GmMYB92 were found to have transactivation activity and can form homodimers. GmMYB177 did not appear to have transactivation activity but can form heterodimers with GmMYB76. Yeast onehybrid assay revealed that all the three GmMYBs could bind to cis-elements TAT AAC GGT TTT TT and CCG GAA AAA AGG AT, but with different affinity, and GmMYB92 could also bind to TCT CAC CTA CC. The transgenic Arabidopsis plants overexpressing GmMYB 76 or GmMYB177 showed better performance than the GmMYB92-transgenic plants in salt and freezing tolerance. However, these transgenic plants exhibited reduced sensitivity to ABA treatment at germination stage in comparison with the wild-type plants. The three GmMYB genes differentially affected a subset of stress-responsive genes in addition to their regulation of a common subset of stress-responsive genes. These resuits indicate that the three GmMYB genes may play differential roles in stress tolerance, possibly through regulation of stress-responsive genes.展开更多
MYB proteins play important roles in eukaryotic organisms. In plants, the R1R2R3-type MYB proteins function in cell cycle control. However, whether the R2R3-type MYB protein is also involved in the cell division proce...MYB proteins play important roles in eukaryotic organisms. In plants, the R1R2R3-type MYB proteins function in cell cycle control. However, whether the R2R3-type MYB protein is also involved in the cell division process remains unknown. Here, we report that an R2R3-type transcription factor gene, AtMYB59, is involved in the regulation of cell cycle progression and root growth. The AtMYB59 protein is localized in the nuclei of onion epidermal cells and has transactivation activity. Expression of AtMYB59 in yeast cells suppresses cell proliferation, and the transfor- mants have more nuclei and higher anenpioid DNA content with longer cells. Mutation in the conserved domain of AtMYB59 abolishes its effects on yeast cell growth. In synchronized Arabidopsis cell suspensions, the AtMYB59 gene is specifically expressed in the S phase during cell cycle progression. Expression and promoter-GUS analysis reveals that the AtMYB59 gene is abundantly expressed in roots. Transgenic plants overexpressing AtMYB59 have shorter roots compared with wild-type plants （Arabidopsis accession Col-0）, and around half of the mitotic cells in root tips are at metaphase. Conversely, the null mutant myb59-1 has longer roots and fewer mitotic cells at metaphase than Col, suggesting that AtMYB59 may inhibit root growth by extending the metaphase of mitotic cells. AtMYB59 regulates many downstream genes, including the CYCB1;1 gene, probably through binding to MYB-responsive elements. These results support a role forAtMYB59 in cell cycle regulation and plant root growth.展开更多
The service condition determines the Roiling Contact Fatigue（RCF） failure mechanism and lifetime under ascertain material structure integrity parameter of thermal spray coating. The available literature on the RCF t...The service condition determines the Roiling Contact Fatigue（RCF） failure mechanism and lifetime under ascertain material structure integrity parameter of thermal spray coating. The available literature on the RCF testing of thermal spray coatings under various condition services is considerable; it is generally difficult to synthesize all of the result to obtain a comprehensive understanding of the parameters which has a great effect on a thermal spray coating＇s resistance of RCF. The effects of service conditions（lubrication states, contact stresses, revolve speed, and slip ratio） on the changing of thermal spray coatings＇ contact fatigue lifetime is introduced systematically. The effects of different service condition on RCF failure mechanism of thermal spray coating from the change of material structure integrity are also summarized. Moreover, In order to enhance the RCF performance, the parameter optimal design formula of service condition and material structure integrity is proposed based on the effect of service condition on thermal spray coatings＇ contact fatigue lifetime and RCF failure mechanism. The shortage of available literature and the forecast focus in future researches are discussed based on available research. The explicit result of RCF lifetime law and parameter optimal design formula in term of lubrication states, contact stresses, revolve speed, and slip ratio, is significant to improve the RCF performance on the engineering application.展开更多
Hepatitis B virus （HBV）-induced liver failure is an emergent liver disease leading to high mortality. The severity of liver failure may be reflected by the profile of some metabolites. This study assessed the potent...Hepatitis B virus （HBV）-induced liver failure is an emergent liver disease leading to high mortality. The severity of liver failure may be reflected by the profile of some metabolites. This study assessed the potential of using metabolites as biomarkers for liver failure by identifying metabolites with good discriminative performance for its phenotype. The serum samples from 24 HBV-indueed liver failure patients and 23 healthy volunteers were collected and analyzed by gas chromatography-mass spectrometry （GC-MS） to generate metabolite profiles. The 24 patients were further grouped into two classes according to the severity of liver failure. Twenty-five eommensal peaks in all metabolite profiles were extracted, and the relative area values of these peaks were used as features for each sample. Three algorithms, F-test, k-nearest neighbor （KNN） and fuzzy support vector machine （FSVM） combined with exhaustive search （ES）, were employed to identify a subset of metabolites （biomarkers） that best predict liver failure. Based on the achieved experimental dataset, 93.62% predictive accuracy by 6 features was selected with FSVM-ES and three key metabolites, glyeerie acid, cis-aeonitie acid and citric acid, are identified as potential diagnostic biomarkers.展开更多
A new method for array calibration of array gain and phase uncertainties, which severely degrade the performance of spatial spectrum estimation, is presented. The method is based on the idea of the instrumental sensor...A new method for array calibration of array gain and phase uncertainties, which severely degrade the performance of spatial spectrum estimation, is presented. The method is based on the idea of the instrumental sensors method （ISM）, two well-calibrated sensors are added into the original array. By applying the principle of estimation of signal parameters via rotational invariance techniques （ESPRIT）, the direction-of-arrivals （DOAs） and uncertainties can be estimated simultaneously through eigen-decomposition. Compared with the conventional ones, this new method has less computational complexity while has higher estimation precision, what＇s more, it can overcome the problem of ambiguity. Both theoretical analysis and computer simulations show the effectiveness of the proposed method.展开更多
The design strategies for powertrain mounting systems play an important role in the reduction of vehicular vibration and noise. As stiffness and damping elements connecting the transmission system and vehicle body, th...The design strategies for powertrain mounting systems play an important role in the reduction of vehicular vibration and noise. As stiffness and damping elements connecting the transmission system and vehicle body, the rubber mount exhibits better vibration isolation performance than the rigid connection. This paper presents a complete design process of the mounting system, including the vibration decoupling, vibration simulation analysis, topology optimization, and experimental verification. Based on the 6?degrees?of?freedom vibration coupling model of the powertrain mounting system, an optimization algorithm is used to extract the best design parameters of each mount, thus rendering the mounting system fully decoupled and the natural frequency well configured, and the optimal parameters are used to design the mounting system. Subsequently, vibration simulation analysis is applied to the mounting system, considering both transmission and road excitations. According to the results of finite element analysis, the topological structure of the metal frame of the front mount is optimized to improve the strength and dynamic characteristics of the mounting system. Finally, the vibration bench test is used to verify the availability of the optimization design with the analysis of acceleration response and vibration transmissibility of the mounting system. The results show that the vibration isolation performance of the mounting system can be improved effectively using the vibration optimal decoupling method, and the structural modification of the metal frame can well promote the dynamic characteristics of the mounting system.展开更多
基金Supported by the 973 State Key Project of China (No.G1999035803)the National Natural Science Foundation of China (No.69931010).
文摘Investigated the properties of LUCas sequence(LUC), the paper proposed a new variant of (probabilistic) public-key encryption scheme. Security analysis of the proposed encryption schemes shows that its one-wayness is equivalent to partial LUC discrete logarithm problem in ZN, and for the proposed probabilistic encryption scheme, its semantic security is equivalent to decisional LUC Diffie-Hellman problem in ZN. At last, the efficiency of the proposed schemes is briefly analyzed.
基金Supported by the National High-Tech Programs(No.2002AAl03062, No.2002AA121061 and No.2003AA103520)the Huawei Technologies Co. (No.YBCN2002001).
文摘To design a Banyan network with an arbitrary even-sized port number, the PN2I network is proposed. The PN2I network can be divided into two classes: the complete and incomplete versions. A simple routing algorithm is given, but in the incomplete PN2I networks,this routing algorithm fails to make the traffic in links even, which deteriorates the performance badly. Thus a new routing algorithm is proposed, which makes the incomplete PN2I networks behave almost the same as the PN2I networks with respect to the performance issues.
基金supported by the National Science and Technology Major Project of China(No.2017-VII-0003-0096)the National Natural Science Foundation of China(Grant Nos.52205240 and 52201140)+2 种基金the Young Elite Scientist Sponsorship Program by CAST(Grant No.YESS20200321)the Natural Science Foundation for Youths of Shaanxi Province(No.2023-JC-QN-0521)the China Postdoctoral Science Foundation(Grant No.2022M723874).
文摘M50 steel,commonly utilized in aircraft engine bearings,is susceptible to friction-induced failures,particularly in high-temperature service conditions.To address this issue,various strategies have been proposed,with laser shock peening(LSP)garnering significant attention due to its deeper residual stress penetration and excellent surface integrity,whereas the underlying strengthening mechanisms have not yet been fully elucidated.In this study,we systematically investigate the impact of LSP treatment on the tribological properties of M50 steel at temperatures of 25 and 300℃,alongside elucidating the relevant micro-mechanisms.Microstructural analysis reveals that laser impact strengthening primarily arises from dislocation proliferation,resulting in a surface hardness increase of approximately 14%and the formation of a substantial compressive stress layer reaching a maximum value of about 1200 MPa,with a depth of around 2 mm.Friction test results demonstrate reduced coefficients of friction and wear rates following LSP treatment at both temperatures.Notably,a more pronounced reduction is observed at 300℃,with values decreasing by 41.4%and 55.8%,respectively.The enhanced performance is attributed to the synergistic interplay of compressive residual stresses,work-hardening layers,increased density of dislocations,and substantial microstructure refinement.
基金supported by the National Natural Science Foundation of China(31972435)to Jintao Cheng,and Agriculture Research System of MOF and MORA(CARS-25)Natural Science Foundation of Hubei Province(2019CFA017)Ningbo Scientific and Technological Project(2021Z006)to Zhilong Bie.
文摘Melon fruit flavor is a key quality characteristic that influences consumer preference.Grafting is an effective technique to enhance fruit quality but yields divergent outcomes in terms of fruit flavor.To address this problem,we analyzed parallel changes in flavor-related metabolite accumulation and gene expression in two pumpkin rootstock grafted melons during four fruit developmental stages.We identified 26061 expressed genes and 840 metabolites from 21 different compound classes,including carbohydrates,amino acids,and lipids.We also detected 50 aroma volatile compounds in the grafted melons.Results showed that genes and metabolites associated with metabolic pathways(carbohydrate,amino acid,lipid,and phenylpropanoid)play a key role in flavor formation.Compared with‘Sizhuang 12’,‘Tianzhen 1’rootstock improved melon fruit flavor by upregulating sugar-related genes(HK,MPI,MIOX,and STP)and inducing metabolite accumulation(d-ribose-5-phosphate,d-galactose,and trehalose 6-phosphate),whereas decreasing bitterness-related amino acids(l-arginine,l-asparagine,and l-tyrosine)and associated genes(thrC,ACS,and GLUL)expression at ripening stage.Furthermore,‘Tianzhen 1’exhibited higher expression levels of enzyme-coding genes(4CL,CSE,and COMT)responsible for aroma volatile synthesis than‘Sizhuang 12’rootstock.Taken together,our results decipher the basis of the molecular mechanism underlying fruit flavor in grafted melons and provide valuable information for the melons genetic improvement.
基金National Social Science Fund of China(No.2023-SKJJ-B-069).
文摘In GNSS denied environments,pseudolites have to rely on prior information,such as ground anchoring points,terrain matching or other multi-source means for positioning.This paper proposes a method of dynamic networking of UAVs pseudolites for accurate navigation with only inertial navigation during GNSS denied area,which can provide accurate positioning services without prior information like anchor points.On this basis,this paper proposes a mathematical model of UAV pseudolite networking to describe the relationship of UAV flight altitude,network service coverage and anti-jamming capabilities.This model demonstrates excellent anti-interference ability,which can achieve a maximum power enhancement of up to 54.58 dB.And it can also offer another operating mode with a maximum coverage range of up to 2675.47 km^(2),while still ensuring a power enhancement of 37.57dB.This method can effectively solve the problem of providing continuous positioning services as an alternative GNSS,and is also a powerful support solution for resilient Positioning,Navigation,and Timing(PNT)^([1]).
文摘Robustness against measurement uncertainties is crucial for gas turbine engine diagnosis.While current research focuses mainly on measurement noise,measurement bias remains challenging.This study proposes a novel performance-based fault detection and identification(FDI)strategy for twin-shaft turbofan gas turbine engines and addresses these uncertainties through a first-order Takagi-Sugeno-Kang fuzzy inference system.To handle ambient condition changes,we use parameter correction to preprocess the raw measurement data,which reduces the FDI’s system complexity.Additionally,the power-level angle is set as a scheduling parameter to reduce the number of rules in the TSK-based FDI system.The data for designing,training,and testing the proposed FDI strategy are generated using a component-level turbofan engine model.The antecedent and consequent parameters of the TSK-based FDI system are optimized using the particle swarm optimization algorithm and ridge regression.A robust structure combining a specialized fuzzy inference system with the TSK-based FDI system is proposed to handle measurement biases.The performance of the first-order TSK-based FDI system and robust FDI structure are evaluated through comprehensive simulation studies.Comparative studies confirm the superior accuracy of the first-order TSK-based FDI system in fault detection,isolation,and identification.The robust structure demonstrates a 2%-8%improvement in the success rate index under relatively large measurement bias conditions,thereby indicating excellent robustness.Accuracy against significant bias values and computation time are also evaluated,suggesting that the proposed robust structure has desirable online performance.This study proposes a novel FDI strategy that effectively addresses measurement uncertainties.
基金the National Natural Science Foundation of China(Nos.52105117,52222504&51875433)the Funds for Distinguished Young talent of Shaanxi Province,China(No.2019JC-04)。
文摘Blade Tip Timing(BTT)enables non-contact measurements of rotating blades by placing probes strategically.Due to the uneven probe layout,BTT signals exhibit periodic irregularities.While recovering parameters like frequency from such signals is possible,achieving high-precision vibration parameters remains challenging.This paper proposed a novel two-stage off-grid estimation method.It leverages a unique array layout(coprime array)to obtain a regular augmented covariance matrix.Subsequently,parameters in the matrix are recovered using the sparse iterative covariance-based estimation method based on covariance fitting criteria.Finally,high-precision estimates of imprecise parameters are obtained using unconditional maximum likelihood estimation,effectively eliminating the effects of basis mismatch.Through substantial numerical and experimental validation,the proposed method demonstrates significantly higher accuracy compared to classical BTT parameter estimation methods,approaching the lower bound of unbiased estimation variance.Furthermore,due to its immunity to frequency gridding,it can track minor frequency deviations,making it more suitable for indicating blade condition.
基金supported in part by the Natural Science Foundation of Xinjiang Uygur Autonomous Region under Grant 2022D01B184the National Natural Science Foundation of China under Grant 62301117,62131005.
文摘Covert communication guarantees the security of wireless communications via hiding the existence of the transmission.This paper focuses on the first and second order asymptotics of covert communication in the AWGN channels.The covertness is measured by the total variation distance between the channel output distributions induced with and without the transmission.We provide the exact expressions of the maximum amount of information that can be transmitted with the maximum error probability and the total variation less than any small numbers.The energy detection and the random coding are employed to prove our results.We further compare our results with those under relative entropy.The results show how many additional amounts of information can be transmitted covertly when changing the covertness constraint to total variation.
基金financially supported by the Shaanxi Provincial Science and Technology Innovation Team,China(No.2024RS-CXTD-26)。
文摘When immersed in sand and dust environment,aero-engine blades are exposed to harsh erosion which may lead to failure if erosion is severe.Using Physical Vapor Deposition(PVD)to prepare hard ceramic coatings can greatly enhance the operational capabilities of aero-engine.However,due to the“line-of-sight”processing characteristic of PVD process,uneven coating deposition rates occur when preparing coatings on obstructed areas such as blisks.Quantitative research on such phenomena is few,and it is even rarer in the study of aero-engine coatings.Based on the analyses and considerations of the geometric shape of blade surfaces and the influence of both deposition and re-sputtering effect,an ideal model is established to analyze the deposition rate variation along blocked region in complex self-shadowing boundaries.The relative deposition rates at various locations on the blade surface within the inter-blade gaps are quantitatively calculated and experimentally validated.Furthermore,differences in erosion resistance of the coatings are tested.The conclusions are drawn as follows:the geometric configuration of the obstructed shape and resputtering phenomenon significantly influence the deposition rates within the inner wall of blade gaps.Taking the structural configuration as an example,in a 25 mm×60 mm×15 mm gap,the coating thickness can vary more than 252%from the thickest to the thinnest location.The deposition rates of various locations are proportional to the solid angle of incident ion in more obstructed regions,and the re-sputtering is more prominent in open regions.Obstructive boundaries directly affect the erosion resistance at various locations within the gaps,with erosion failure time decreasing by 40%in heavily blocked region compared to open region.
基金supported by the National Key Lab of Aerospace Power System and Plasma Technology Foundation,China(No.6142202210101)the National Science and Technology Major Project,China(No.J2019-Ⅲ-0013-0056)+2 种基金the National Natural Science Foundation of China(No.52025064)supported by the National Natural Science Foundation of China(Nos.52350072 and 52277167)the Beijing Natural Science Foundation,China(No.1242030)。
文摘Plasma-assisted combustion technology has been a hot spot in aero-engines andscramjet-engines.The electron density is a key discharge parameter related to the active-particledensity.The latter has been considered playing an important role in the above applications bythe kinetic effect.In this work,an atmospheric pressure air plasma collisional-radiative model con-sidering the excited states of atomic nitrogen and oxygen is built based on previous widely kineticinvestigations of molecules and radicals,as well as their excited states.The excited states,especiallythe atomic nitrogen and oxygen states were less investigated in previous works.The emission inten-sity distributions from the model have a good agreement with those measured in the glide arcplasma with two discharge modes,as well as the microwave plasma.Based on the kinetics of molec-ular and atomic emitting states,the line-ratio method is presented to determine the electron density.The N_(2)(337 nm)/O(844 nm)and N_(2)(337 nm)/NO(γ)line ratios are used for the glide arc plasma andmicrowave plasma torch,respectively.Besides,the kinetics of the excited states involved with twoline-ratios are also investigated in the two types of discharges.Combined with the atmospheric pres-sure actinometry method,the kinetic effect of the plasma-assisted combustion can be revealed quan-titatively in the future.
基金supported by the Beijing Natural Sci-ence Foundation(No.L242139).
文摘The durability of dental implant carrier coatings is of paramount importance for the expeditious and predictable osseointegration process.The present work is based on a bionic micro/nano hierarchy struc-ture,which consists of titanium surface microstructures and their internal TiO2 nanotubes(TNTs)with drug-carrying capacity.This effectively increases the wear resistance of the drug-carrying coating on the titanium surface.In comparison to untextured samples,the wear volume and wear depth of the optimal texture group are markedly diminished,resulting in a significant enhancement of wear resistance.This improvement was primarily attributed to the smaller contact area of the microstructure.Concurrently,the microstructure serves to safeguard the TNTs from damage during friction.The hydrophilic biomimetic anti-wear micro/nano hierarchies demonstrated the capacity to promote MC3T3-E1 cell adhesion and pro-liferation,while also exhibiting no cytotoxic effects.Moreover,the micro/nano hierarchical structure can be directly applied to the surface of commercialized implants.In simulated clinical conditions,the im-plant was inserted into a fresh Bama porcine mandible,and the structure of the drug-loading coatings remained intact.This structure enhances the abrasion resistance of the drug coating while minimizing alterations to the original treatment process of the implant,which is of great significance in the clinical application of implant-loaded drug delivery.
基金supported by Project of Renovation Capacity Building for the Young Sci-Tech Talents Sponsored by Xinjiang Academy of Agricultural Sciences(Grant No.xjnkq-2021011)Key Research and Development Program of Hainan Province(Grant No.ZDYF2025XDNY089)+2 种基金Project of Fund for Stable Support to Agricultural Sci-Tech Renovation(Grant No.xjnkywdzc-2023001-35)Guangxi Agricultural Science and Technology Project,China Agriculture Research System of MOF and MORA(CARS-25)the Fundamental Research Funds for the Central Universities(Grant No.2662024JC004)。
文摘Melon(Cucumis melo L.)is a globally important fruit crop appreciated for its sweet taste,unique aroma,and nutritional value(Kaleem et al.,2024).Aroma,shaped by volatile organic compounds(VOCs),is a key trait influencing consumer preference.These VOCs are mainly derived from amino acids,fatty acids,and terpenoid pathways(Chen et al.,2023).Esters contribute to fruity and sweet notes,whereas terpenes and C_(9) aldehydes/alcohols impart floral and melon-like aromas,respectively(Mayobre et al.,2024).
基金the support by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB0620303)the Natural Science Basic Research Program of Shanxi(Program No.2023-JC-QN-0044).
文摘In this study,the efects of defect,mean stress and lower loading are investigated for high cycle(HCF)and very high cycle fatigue(VHCF)behavior of Ti-6Al-4V alloy.It indicates that the S-N curve of Ti-6Al-4V alloy exhibits a linear decreasing trend or a plateau characteristic in HCF and VHCF regimes,which depends on the defect size and stress ratio.VHCF strength decreases with increasing the defect size,and it is irrespective of stress ratios.The fatigue crack initiates from specimen surface at R=−1 in both HCF and VHCF regimes.While the fatigue crack initiates from the subsurface or the interior of the specimen at R=0.1 in VHCF regime.A sequence of lower stress amplitude below the fatigue strength at 10^(9) cyc has no or negligible infuence on the fatigue life of 10^(5)-10^(9) cyc.The lower stress amplitude in variable amplitude loadings does not afect the failure mechanism.The residual compressive stress relaxation is not observed after a large number of lower loadings under ultrasonic frequency fatigue test.Gerber formula and Goodman formula give dangerous predictions of VHCF strength for both smooth specimens and specimens with defects.
基金financially supported by the National Natural Science Foundation of China(Nos.12204355,52272210,12364006 and 12164011)the Open Project of State Key Laboratory of Superhard Materials,Jilin University(No.202110)the Natural Science Foundation of Shandong Province(Nos.ZR2022QA018,ZR2023QE282,ZR2023ME001 and ZR2023MF081)
文摘GeTe-based alloys are promising thermoelectric materials for use at medium temperatures owing to their excellent thermoelectric performance.In this study,Ge_(0.8-x)Mn_(0.1)Pb_(0.1)Sb_(x)Te alloys were obtained via vacuum melting and hot-press sintering.Sb doping effectively decreased the carrier concentration,resulting in an enhancement of the Seebeck coefficient and consequently imparting excellent electrical transport performance to the sample.With doping concentration increasing,the structure of the sample changed from rhombohedral to cubic,creating a more favorable band structure for electronic transport properties.The incorporation of Sb into GeTe intensifies the lattice defects within the material.The significant decrease in the lattice thermal conductivity of the Ge_(0.71)Mn_(0.1)Pb_(0.1)Sb_(0.09)Te alloy to 0.84 W m^(-1)K^(-1)at 323 K is primarily attributed to the phonon scattering effect emanating from the presence of edge dislocation,point defects,and inherent grain boundaries.Finally,the maximum ZT value of the Ge_(0.74)Mn_(0.1)Pb_(0.1)Sb_(0.06)Te alloy was~1.53773 K,which is a significant enhancement of 0.35 compared to the undoped Ge_(0.8)Mn_(0.1)Pb_(0.1)Te alloy.This substantial improvement underscores the positive impact of the selected doping elements and their concentrations on the overall thermoelectric performance of the alloy.
基金Acknowledgments This work was supported by the National Natural Science Foundation of China （30490254, 30671316）, the National Basic Research Program of China （2006CB100102）, and the Hi-Tech Research and Development Program of China （2006AA10Z113, 2006AA10A111）.
文摘MYB-type transcription factors contain the conserved MYB DNA-binding domain of approximately 50 amino acids and are involved in the regulation of many aspects of plant growth, development, metabolism and stress responses. From soybean plants, we identified 156 GmMYB genes using our previously obtained 206 MYB unigenes, and 48 were found to have full-length open-reading frames. Expressions of all these identified genes were examined, and we found that expressions of 43 genes were changed upon treatment with ABA, salt, drought and/or cold stress. Three GmMYB genes, GmMYB76, GmMYB92 and GmMYB177, were chosen for further analysis. Using the yeast assay system, GmMYB76 and GmMYB92 were found to have transactivation activity and can form homodimers. GmMYB177 did not appear to have transactivation activity but can form heterodimers with GmMYB76. Yeast onehybrid assay revealed that all the three GmMYBs could bind to cis-elements TAT AAC GGT TTT TT and CCG GAA AAA AGG AT, but with different affinity, and GmMYB92 could also bind to TCT CAC CTA CC. The transgenic Arabidopsis plants overexpressing GmMYB 76 or GmMYB177 showed better performance than the GmMYB92-transgenic plants in salt and freezing tolerance. However, these transgenic plants exhibited reduced sensitivity to ABA treatment at germination stage in comparison with the wild-type plants. The three GmMYB genes differentially affected a subset of stress-responsive genes in addition to their regulation of a common subset of stress-responsive genes. These resuits indicate that the three GmMYB genes may play differential roles in stress tolerance, possibly through regulation of stress-responsive genes.
文摘MYB proteins play important roles in eukaryotic organisms. In plants, the R1R2R3-type MYB proteins function in cell cycle control. However, whether the R2R3-type MYB protein is also involved in the cell division process remains unknown. Here, we report that an R2R3-type transcription factor gene, AtMYB59, is involved in the regulation of cell cycle progression and root growth. The AtMYB59 protein is localized in the nuclei of onion epidermal cells and has transactivation activity. Expression of AtMYB59 in yeast cells suppresses cell proliferation, and the transfor- mants have more nuclei and higher anenpioid DNA content with longer cells. Mutation in the conserved domain of AtMYB59 abolishes its effects on yeast cell growth. In synchronized Arabidopsis cell suspensions, the AtMYB59 gene is specifically expressed in the S phase during cell cycle progression. Expression and promoter-GUS analysis reveals that the AtMYB59 gene is abundantly expressed in roots. Transgenic plants overexpressing AtMYB59 have shorter roots compared with wild-type plants （Arabidopsis accession Col-0）, and around half of the mitotic cells in root tips are at metaphase. Conversely, the null mutant myb59-1 has longer roots and fewer mitotic cells at metaphase than Col, suggesting that AtMYB59 may inhibit root growth by extending the metaphase of mitotic cells. AtMYB59 regulates many downstream genes, including the CYCB1;1 gene, probably through binding to MYB-responsive elements. These results support a role forAtMYB59 in cell cycle regulation and plant root growth.
基金Supported by Distinguished Young Scholars of National Natural Science Foundation of China(Grant No.51125023)National Basic Research Program of China(973program,Grant No.2011CB013405)+1 种基金National Natural Science Foundation of China(Grant Nos.5127552651275105)Fundamental Research Funds for the Central Universities(Grant Nos.HEUCF20130910003,201403017)
文摘The service condition determines the Roiling Contact Fatigue（RCF） failure mechanism and lifetime under ascertain material structure integrity parameter of thermal spray coating. The available literature on the RCF testing of thermal spray coatings under various condition services is considerable; it is generally difficult to synthesize all of the result to obtain a comprehensive understanding of the parameters which has a great effect on a thermal spray coating＇s resistance of RCF. The effects of service conditions（lubrication states, contact stresses, revolve speed, and slip ratio） on the changing of thermal spray coatings＇ contact fatigue lifetime is introduced systematically. The effects of different service condition on RCF failure mechanism of thermal spray coating from the change of material structure integrity are also summarized. Moreover, In order to enhance the RCF performance, the parameter optimal design formula of service condition and material structure integrity is proposed based on the effect of service condition on thermal spray coatings＇ contact fatigue lifetime and RCF failure mechanism. The shortage of available literature and the forecast focus in future researches are discussed based on available research. The explicit result of RCF lifetime law and parameter optimal design formula in term of lubrication states, contact stresses, revolve speed, and slip ratio, is significant to improve the RCF performance on the engineering application.
基金Project supported by the Postdoctoral Science Foundation of China(No.20070410397)the National Natural Science Foundation of China(No.60705002)the Science and Technology Project of Zhejiang Province,China(No.2005C13026)
文摘Hepatitis B virus （HBV）-induced liver failure is an emergent liver disease leading to high mortality. The severity of liver failure may be reflected by the profile of some metabolites. This study assessed the potential of using metabolites as biomarkers for liver failure by identifying metabolites with good discriminative performance for its phenotype. The serum samples from 24 HBV-indueed liver failure patients and 23 healthy volunteers were collected and analyzed by gas chromatography-mass spectrometry （GC-MS） to generate metabolite profiles. The 24 patients were further grouped into two classes according to the severity of liver failure. Twenty-five eommensal peaks in all metabolite profiles were extracted, and the relative area values of these peaks were used as features for each sample. Three algorithms, F-test, k-nearest neighbor （KNN） and fuzzy support vector machine （FSVM） combined with exhaustive search （ES）, were employed to identify a subset of metabolites （biomarkers） that best predict liver failure. Based on the achieved experimental dataset, 93.62% predictive accuracy by 6 features was selected with FSVM-ES and three key metabolites, glyeerie acid, cis-aeonitie acid and citric acid, are identified as potential diagnostic biomarkers.
文摘A new method for array calibration of array gain and phase uncertainties, which severely degrade the performance of spatial spectrum estimation, is presented. The method is based on the idea of the instrumental sensors method （ISM）, two well-calibrated sensors are added into the original array. By applying the principle of estimation of signal parameters via rotational invariance techniques （ESPRIT）, the direction-of-arrivals （DOAs） and uncertainties can be estimated simultaneously through eigen-decomposition. Compared with the conventional ones, this new method has less computational complexity while has higher estimation precision, what＇s more, it can overcome the problem of ambiguity. Both theoretical analysis and computer simulations show the effectiveness of the proposed method.
基金Supported by National Natural Science Foundation of China(Grant Nos.51375047,51775040)
文摘The design strategies for powertrain mounting systems play an important role in the reduction of vehicular vibration and noise. As stiffness and damping elements connecting the transmission system and vehicle body, the rubber mount exhibits better vibration isolation performance than the rigid connection. This paper presents a complete design process of the mounting system, including the vibration decoupling, vibration simulation analysis, topology optimization, and experimental verification. Based on the 6?degrees?of?freedom vibration coupling model of the powertrain mounting system, an optimization algorithm is used to extract the best design parameters of each mount, thus rendering the mounting system fully decoupled and the natural frequency well configured, and the optimal parameters are used to design the mounting system. Subsequently, vibration simulation analysis is applied to the mounting system, considering both transmission and road excitations. According to the results of finite element analysis, the topological structure of the metal frame of the front mount is optimized to improve the strength and dynamic characteristics of the mounting system. Finally, the vibration bench test is used to verify the availability of the optimization design with the analysis of acceleration response and vibration transmissibility of the mounting system. The results show that the vibration isolation performance of the mounting system can be improved effectively using the vibration optimal decoupling method, and the structural modification of the metal frame can well promote the dynamic characteristics of the mounting system.
