Rhodiola crenulate is the edible medicinal herbal medicine widely used for altitude sickness in China.Interestingly,our previous work has found that R.crenulate extract(RCE)could significantly improve the pathology as...Rhodiola crenulate is the edible medicinal herbal medicine widely used for altitude sickness in China.Interestingly,our previous work has found that R.crenulate extract(RCE)could significantly improve the pathology associated with dextran sulfate sodium-induced colitis.Thus,the current research aims to reveal the pharmacodynamic material basis of RCE,as well as its mechanism against colitis.The chemical characterization of RCE was performed by UHPLC-HR-MS,through which a total of 88 constituents were identified.Meanwhile,our results also found 29 constituents absorbed into blood and 8 metabolized absorbable compounds.The decreased flavonoids prototype and the elevated sulfated products of phenols were observed under pathophysiological conditions of colitis.The metabolomics study revealed that colitis caused the alternation of fatty acid metabolism,steroid hormone biosynthesis and bile acid metabolism.Correspondingly,RCE could prevent colitis by improving fatty acid metabolism and secondary bile acid metabolism.展开更多
Multidirectional forging(MDF)was successfully applied to fabricate large-size Mg-Gd-Y-Zn-Zr-Ag alloy in this work and effects of T4,T5 and T6 treatments on the microstructure and mechanical properties of the as-forged...Multidirectional forging(MDF)was successfully applied to fabricate large-size Mg-Gd-Y-Zn-Zr-Ag alloy in this work and effects of T4,T5 and T6 treatments on the microstructure and mechanical properties of the as-forged alloy were analyzed.Results show that dynamic recrystallization(DRX)occurs and second phase particles precipitate along the grain boundary during the MDF process.After annealing treatment(T4),the volume fraction and size of dynamic precipitates slightly increase at a lower temperature(430℃)compared with those of MDFed sample,while they are dissolved into theα-Mg matrix at a higher temperature(450℃).At the meantime,short plate-shaped long-period stacking ordered(LPSO)phases are observed in the DRX grains of the MDFed sample and then dissolved into theα-Mg matrix during annealing at both temperatures.Typical basal texture is identified in the MDFed sample,but the basal pole tilts away from final forging direction and rare-earth texture component with<1121>orientation parallel to penultimate forging direction becomes visible after annealing.The T6 sample annealing at 430℃for 4 h and ageing at 200℃for 34 h exhibits the superior strength and ductility in this study.The ultimate tensile strength,tensile yield strength and elongation to failure,which is 455 MPa,308 MPa and 7.7%,respectively,are overall improved compared with the directly-aged(T5)sample.This paper provides a superior heat treatment schedule to manufacture high-performance large-scale Mg-Gd-Y-Zn-Zr-Ag components for industrial production.展开更多
This paper addresses the decentralized consensus problem for a system of multiple dynamic agents with remote controllers via networking,known as a networked control multi-agent system(NCMAS).It presents a challenging ...This paper addresses the decentralized consensus problem for a system of multiple dynamic agents with remote controllers via networking,known as a networked control multi-agent system(NCMAS).It presents a challenging scenario where partial dynamic entities or remote control units are vulnerable to disclosure attacks,making them potentially malicious.To tackle this issue,we propose a secure decentralized control design approach employing a double-layer cryptographic strategy.This approach not only ensures that the input and output information of the benign entities remains protected from the malicious entities but also practically achieves consensus performance.The paper provides an explicit design,supported by theoretical proof and numerical verification,covering stability,steady-state error,and the prevention of computation overflow or underflow.展开更多
A bulk nanocrystalline AZ31B Mg alloy with extraordinarily high strength was prepared via cryogenic rotary swaging in this study.The obtained alloy shows finer grains,higher strength,and a negligible tension-compressi...A bulk nanocrystalline AZ31B Mg alloy with extraordinarily high strength was prepared via cryogenic rotary swaging in this study.The obtained alloy shows finer grains,higher strength,and a negligible tension-compression yield asymmetry,compared with that prepared via room-temperature rotary swaging.Transmission electron microscopy investigations showed that at the initial stage,multiple twins,mostly tension twins,were activated and intersected with each other,thereby refining the coarse grains into a fine lamellar structure.Then,two types of nanoscale subgrains were generated with increasing swaging strain.The first type of nanoscale subgrain contained twin boundaries and low-angle grain boundaries.This type of subgrain appeared at the twin-twin intersections and was mainly driven by high local stress.The second type of nanoscale subgrain was formed within the twin lamellae.The boundaries of this type of subgrain did not contain twin boundaries and were transformed from massive dislocation arrays.Finally,randomly oriented nanograins were obtained via dynamic recrystallization,under the combined function of deformation heat and increased stored energy.Compared with room-temperature rotary swaging,cryogenic rotary swaging exhibits a slower grain refinement process but a remarkably enhanced grain refinement effect after the same five-pass swaging.展开更多
Mg-6.75Zn-0.57Zr-0.4Y-0.18Gd(wt.%)sheet with typical basal texture was produced by cross rolling and annealing.Room temperature tensile tests were subsequently conducted along rolling direction(RD),transverse directio...Mg-6.75Zn-0.57Zr-0.4Y-0.18Gd(wt.%)sheet with typical basal texture was produced by cross rolling and annealing.Room temperature tensile tests were subsequently conducted along rolling direction(RD),transverse direction(TD),and diagonal direction(RD45).Deformation mechanism and orientation evolution during the tension were investigated by quasi-in-situ electron backscatter diffraction observation and in-grain misorientation axis analysis.The results indicate that the activation of deformation mechanism mainly depends on the initial grain orientation.For RD sample,prismatic<a>slip plays an important role in the deformation of grains with<0001>axis nearly perpendicular to the RD.With the<0001>axis gradually tilted towards the RD,basal<a>slip becomes the dominant deformation mode.After the tensile fracture,the initial concentrically distributed{0001}pole is split into double peaks extending perpendicular to the RD,and the randomly distributed{1010}pole becomes parallel to the RD.The evolution in{0001}and{1010}poles during tension is related to the lattice rotation induced by basal<a>slip and prismatic<a>slip,respectively.TD and RD45 samples exhibit similar deformation mechanism and orientation evolution as the RD sample,which results in the nearly isotropic mechanical properties in the annealed cross-rolled sheet.展开更多
Lipid peroxidation mediated by oxygen radical is one of the main mechanisms underlying secondary brain injury. Among all vitamin E compounds, α-tocopherol shows the most prominent antioxidative effects. It plays an i...Lipid peroxidation mediated by oxygen radical is one of the main mechanisms underlying secondary brain injury. Among all vitamin E compounds, α-tocopherol shows the most prominent antioxidative effects. It plays an important role in cell aging and injury. However, there has been no report regarding the effects of α-tocopherol on changes in brain tissue morphology after intracerebral hemorrhage (ICH), cerebral edema, or the expression of Bax and Bcl-2 proteins. We use SD rats to carry out the related studies;based on the atlas of SD rats, the caudate nucleus was positioned using a stereotaxic apparatus, and 50 μl autologous tail artery blood was injected to caudate nucleus in the ICH and α-tocopherol groups to establish ICH model. Rats in the sham surgery group received the same volume of saline in the caudate nucleus. Rats in the α-tocopherol group received intraperitoneal injections of α-tocopherol at 600 mg/kg every day. Rats in the ICH group and sham surgery group received the same amount of saline at the same times as those in the α-tocopherol group. We observed some interesting results: comparisons of brain tissue sections of rats from different groups showed that brain tissue damage and functional neurological deficits among rats from the α-tocopherol group were less pronounced than in the ICH group. Wet weight/ dry weight measurement showed that rats from the α-tocopherol group exhibited less cerebral edema than those in the ICH group. Rats from the α-tocopherol group showed less Bax expression and more Bcl-2 expression than those in the ICH group.展开更多
This paper considers a UAV communication system with mobile edge computing(MEC).We minimize the energy consumption of the whole system via jointly optimizing the UAV's trajectory and task assignment as well as CPU...This paper considers a UAV communication system with mobile edge computing(MEC).We minimize the energy consumption of the whole system via jointly optimizing the UAV's trajectory and task assignment as well as CPU's computational speed under the set of resource constrains.To this end,we first derive the energy consumption model of data processing,and then obtain the energy consumption model of fixed-wing UAV's flight.The optimization problem is mathematically formulated.To address the problem,we first obtain the approximate optimization problem by applying the technique of discrete linear state-space approximation,and then transform the non-convex constraints into convex by using linearization.Furthermore,a concave-convex procedure(CCCP) based algorithm is proposed in order to solve the optimization problem approximately.Numerical results show the efficacy of the proposed algorithm.展开更多
Trees on sand dunes are more sensitive to environmental changes because sandy soils have extremely low water holding capacity and nutrient availability. We investigated the dynamics of soil respiration(Rs) for seconda...Trees on sand dunes are more sensitive to environmental changes because sandy soils have extremely low water holding capacity and nutrient availability. We investigated the dynamics of soil respiration(Rs) for secondary natural Litsea forest and plantations of casuarina,pine, acacia and eucalyptus. Results show that significant diurnal variations of Rsoccurred in autumn for the eucalyptus species and in summer for the pine species, with higher mean soil respiration at night. However, significant seasonal variations of Rswere found in all five forest stands. Rschanged exponentially with soil temperatures at the 10-cm depth; the models explain 43.3–77.0% of Rs variations. Positive relationships between seasonal Rsand soil moisture varied with stands. The correlations were significant only in the secondary forest, and the eucalyptus and pine plantations. The temperature sensitivity parameter(Q10 value) of Rsranged from 1.64 in casuarina plantation to 2.32 the in secondary forest; annual Rswas highest in the secondary forest and lowest in the pine plantation. The results indicate that soil temperatures and moisture are the primary environmental controls of soil respiration and mainly act through a direct influence on roots and microbial activity. Differences in root biomass, quality of litter,and soil properties(pH, total N, available P, and exchangeable Mg) were also significant factors.展开更多
The tensile deformation behavior and corresponding microstructure evolution of the Mg-4.7Gd-3.4Y-1.2Zn-0.5Zr(at.%)magnesium alloy with long period stacking structure(LPSO)are studied by electron backscatter diffractio...The tensile deformation behavior and corresponding microstructure evolution of the Mg-4.7Gd-3.4Y-1.2Zn-0.5Zr(at.%)magnesium alloy with long period stacking structure(LPSO)are studied by electron backscatter diffraction(EBSD)and slip lines methods.The results show that less and very small size of twins is observed in the grains with high value of Schmid factor for twinning,which indicates that the growth of the{10–12}twinning deformation is prevented by the LPSO phase.The prismatic lines present in grains of which the prismatic slip Schmid factor is above 0.4.The favorable orientation and LPSO phase synergistically promote the activation of prismatic slip.The inhomogeneous rotation of the grains during deformation is the reason for the microcrack at grain boundary.展开更多
Sugarcane is a prominent source of sugar and ethanol production.Genetic analysis for trait improvement of sugarcane is greatly hindered by its complex genome,long breeding cycle,and recalcitrance to genetic transforma...Sugarcane is a prominent source of sugar and ethanol production.Genetic analysis for trait improvement of sugarcane is greatly hindered by its complex genome,long breeding cycle,and recalcitrance to genetic transformation.The protoplast-based transient transformation system is a versatile and convenient tool for in vivo functional gene analysis;however,quick and effective transformation systems are still lacking for sugarcane.Here,we developed an efficient protoplast-based transformation system by optimizing conditions of protoplasts isolation and PEG-mediated transformation in S.spontaneum.The yield of viable protoplasts was approximately 1.26×107 per gram of leaf material,and the transformation efficiency of 80.19%could be achieved under the optimized condition.Furthermore,using this approach,the nuclear localization of an ABI5-like bZIPs transcription factor was validated,and the promoter activity of several putative DNase I hypersensitive sites(DHSs)was assessed.The results indicated this system can be conveniently applied to protein subcellular localization and promoter activity assays.A highly efficient S.spontaneum mesophyll cell protoplast isolation and transient transformation method was developed,and it shall be suitable for in vivo functional gene analysis in sugarcane.展开更多
In order to get the correct isotopic age, SHRIMP U-Pb zircon date of Precambrian hornblende granite in Well TD2, located in the central aeromagnetic belt in the eastern of the Tarim basin, was carried out. The result ...In order to get the correct isotopic age, SHRIMP U-Pb zircon date of Precambrian hornblende granite in Well TD2, located in the central aeromagnetic belt in the eastern of the Tarim basin, was carried out. The result showed a dependable age of 1908.2 ± 8.6 Ma, which demonstrated that the granite pluton is the result of the magmatic activity in early Palaeoproterozoic. It is indicated that the central aeromagnetic belt across Tarim basin, divided it into north and south block, is formed before Neoproterozoic by a large scale tectonothermal events based on the seismic and drilling date. The Tarim continent may have different age and type basements formed the united crystalline basement in Precambrian. This result has yielded new intraplate evidence to constrain the relation between the Tarim plate and the Colombia supercontinent.展开更多
Simultaneous achievement in high solid content and high microsphere yield is deemed a challenge in the fabrication of monodisperse microspheres by precipitation polymerization.We herein demonstrate that micro-sized mo...Simultaneous achievement in high solid content and high microsphere yield is deemed a challenge in the fabrication of monodisperse microspheres by precipitation polymerization.We herein demonstrate that micro-sized monodisperse poly(methacrylic monomer-divinylbenzene)microspheres containing epoxy,lauyl,carboxyl and hydroxyl functions can be fabricated by solvothermal precipitation copolymerization at 20%(mass)monomer loading with over 94%microsphere yield.The morphology and porosity of the obtained particles can be readily tuned by cosolvent-acetonitrile binary solvents.Addition of a small amount of cosolvent that has similar solubility parameter to that of the functional monomer can significantly improve the monodispersity of the obtained microspheres.When tetrahydrofuran was used as the co-solvent,the surface area of the highly porous microspheres achieved higher than 400 m^(2)·g^(-1).Solvothermal precipitation co-polymerization can be expected in scale-up fabrication of various monodisperse functional microspheres free of any surfactant and additive.展开更多
Motivated by 5th generation wireless systems(5G),a large number of emerging applications appear,which put forward higher requirements for the task’s transmission determinacy,which refers to the delay and jitter.To sa...Motivated by 5th generation wireless systems(5G),a large number of emerging applications appear,which put forward higher requirements for the task’s transmission determinacy,which refers to the delay and jitter.To satisfy the deterministic requirement,mobile edge computing(MEC)is envisioned as a promising technique for reducing the end-to-end delay significantly.In this paper,we consider delaysensitive task and jitter-sensitive task,and then formulate the joint communications and computing optimization problem under the latency,the total bandwidth,the total transmission power of base station(BS)and the computing ability of the MEC server constraints to minimize the delay and jitter in a multiuser MEC system.Because of the problems are nonconvex,we decouple them into some subproblems and propose the corresponding algorithms to obtain a suboptimal solution.Finally,numerical results show that the proposed algorithms have a significant performance gain over the traditional solution in terms of the delay and the jitter.展开更多
With the rapid development of smart terminals and infrastructures,as well as diversified applications(e.g.,autonomous driving,virtual and augmented reality,space-air-ground integrated networks)with colorful demands,cu...With the rapid development of smart terminals and infrastructures,as well as diversified applications(e.g.,autonomous driving,virtual and augmented reality,space-air-ground integrated networks)with colorful demands,current networks(e.g.,4G and 5G networks)may not be well suited to the requirements of novel applications and services.Recently,efforts from both the industry and academia have been made on the research into 6G networks,artificial intelligence(AI)will play a pivotal role in the design and optimization of 6G networks.展开更多
The edge cache is an effective way to reduce the heavy traffic load and the end-to-end latency in radio access networks(RANs)for supporting a number of critical Internet of Things(IoT)services and applications.It has ...The edge cache is an effective way to reduce the heavy traffic load and the end-to-end latency in radio access networks(RANs)for supporting a number of critical Internet of Things(IoT)services and applications.It has been verified to provide high spectral efficiency,high energy efficiency,and low latency.To exploit the advantages of edge cache,a paradigm of fog computing-based radio access networks(F-RANs)has emerged to provide great flexibility to satisfy quality-of-service requirements of various IoT applications in the fifth generation(5G)wireless systems.展开更多
The deformation mechanism,microstructure evolution,and precipitation behavior of a Mg-8.9Gd-1.8Y-0.5Zr-0.2Ag(wt.%)alloy multi-directionally forged at three different temperatures were investigated.As the forging tempe...The deformation mechanism,microstructure evolution,and precipitation behavior of a Mg-8.9Gd-1.8Y-0.5Zr-0.2Ag(wt.%)alloy multi-directionally forged at three different temperatures were investigated.As the forging temperature increases,the particle-stimulated nucleation(PSN)effect diminishes as the num-ber of dynamic precipitates decreases,pyramidal slip is activated,grain boundary migration accelerates,and continuous dynamic recrystallization(CDRX)dominates.The microstructures varied greatly,although fine-grained structures were formed at all different forging temperatures.Competitive precipitation be-tween dynamic precipitate growth,dislocation-induced precipitation,and homogeneous precipitation was observed after aging treatment.Among them,the medium temperature(748 K)forged and aged alloy ex-hibits the best mechanical performance,with an ultimate tensile strength of 436 MPa,and elongation of 16.3%.The calculation indicates that the mixed precipitation structure containing theβprecipitate band provides a 35%higher strengthening contribution than the typical homogeneously distributed precipi-tates.The formation of precipitation-free zones(PFZs)ensures that aging will not cause a dramatic de-crease in ductility,which provides a reference for the industrial preparation of high-performance wrought Mg-Gd series alloys.展开更多
A wearable sensing system that can reconstruct dynamic 3D human body models for virtual cloth fitting is highly important in the era of information and metaverse.However,few research has been conducted regarding confo...A wearable sensing system that can reconstruct dynamic 3D human body models for virtual cloth fitting is highly important in the era of information and metaverse.However,few research has been conducted regarding conformal sen-sors for accurately measuring the human body circumferences for dynamic 3D human body reshaping.Here,we develop a stretchable spring-sheathed yarn sensor(SSYS)as a smart ruler,for precisely measuring the circumference of human bodies and long-term tracking the movement for the dynamic 3D body reconstruction.The SSYS has a robust property,high resilience,high stability(>18000),and ultrafast response(12 ms)to external deformation.It is also washable,wearable,tailorable,and durable for long-time wearing.Moreover,geometric,and mechanical behaviors of the SSYS are systematically investigated both theoretically and experimentally.In addition,a transfer learning algorithm that bridges the discrepancy of real and virtual sensing performance is devel-oped,enabling a small body circumference measurement error of 1.79%,notice-ably lower than that of traditional learning algorithm.Furtherly,3D human bodies that are numerically consistent with the actual bodies are reconstructed.The 3D dynamic human body reconstruction based on the wearing sensing sys-tem and transfer learning algorithm enables excellent virtual fitting and shirt customization in a smart and highly efficient manner.This wearable sensing technology shows great potential in human-computer interaction,intelligent fitting,specialized protection,sports activities,and human physiological health tracking.展开更多
Isomerization of glucose to fructose is a fundamental and key intermediate process commonly included in the production of valuable chemicals from carbohydrates in biorefinery.Enhancement of fructose yield is a challen...Isomerization of glucose to fructose is a fundamental and key intermediate process commonly included in the production of valuable chemicals from carbohydrates in biorefinery.Enhancement of fructose yield is a challenge.In this work,Sn-doped silica nanotube(Sn-SNT)was developed as a highly efficient Lewis acid catalyst for the selective isomerization of glucose to fructose.Over Sn-SNT,69.1%fructose yield with 78.5%selectivity was obtained after reaction at 110◦C for 6 h.The sole presence of a large amount of Lewis acid sites in Sn-SNT without Brønsted acid site is one of the reasons for the high fructose yield and selectivity.Otherwise,high density of SiOH groups in Sn-SNT can ensure the presence of SiOH groups near the Sn sites,which is important for the isomerization of glucose to fructose,leading to the high fructose yield and selectivity.Furthermore,the Sn-SNT is recyclable.展开更多
基金supported by China Postdoctoral Science Foundation(2021M701759)Nanjing Medical University Science and Technology Development Fund(NMUB20210012)+4 种基金Jiangsu Provincial Outstanding Postdoctoral Programme(2022ZB430)National Natural Science Foundation of China(grant No.81873654,82201579)Open Research Fund of State Key Laboratory of Southwestern Chinese Medicine Resources(SKLTCM2022020)Guangdong Provincial Key Laboratory of Lingnan Specialty Food Science and Technology(kjzr220009)Zhejiang Province Key Laboratory of Medical Electronics and Digital Health(MEDH2022016)。
文摘Rhodiola crenulate is the edible medicinal herbal medicine widely used for altitude sickness in China.Interestingly,our previous work has found that R.crenulate extract(RCE)could significantly improve the pathology associated with dextran sulfate sodium-induced colitis.Thus,the current research aims to reveal the pharmacodynamic material basis of RCE,as well as its mechanism against colitis.The chemical characterization of RCE was performed by UHPLC-HR-MS,through which a total of 88 constituents were identified.Meanwhile,our results also found 29 constituents absorbed into blood and 8 metabolized absorbable compounds.The decreased flavonoids prototype and the elevated sulfated products of phenols were observed under pathophysiological conditions of colitis.The metabolomics study revealed that colitis caused the alternation of fatty acid metabolism,steroid hormone biosynthesis and bile acid metabolism.Correspondingly,RCE could prevent colitis by improving fatty acid metabolism and secondary bile acid metabolism.
基金supported by National Natural Science Foundation of China(Grant No.51874367 and 51574291)。
文摘Multidirectional forging(MDF)was successfully applied to fabricate large-size Mg-Gd-Y-Zn-Zr-Ag alloy in this work and effects of T4,T5 and T6 treatments on the microstructure and mechanical properties of the as-forged alloy were analyzed.Results show that dynamic recrystallization(DRX)occurs and second phase particles precipitate along the grain boundary during the MDF process.After annealing treatment(T4),the volume fraction and size of dynamic precipitates slightly increase at a lower temperature(430℃)compared with those of MDFed sample,while they are dissolved into theα-Mg matrix at a higher temperature(450℃).At the meantime,short plate-shaped long-period stacking ordered(LPSO)phases are observed in the DRX grains of the MDFed sample and then dissolved into theα-Mg matrix during annealing at both temperatures.Typical basal texture is identified in the MDFed sample,but the basal pole tilts away from final forging direction and rare-earth texture component with<1121>orientation parallel to penultimate forging direction becomes visible after annealing.The T6 sample annealing at 430℃for 4 h and ageing at 200℃for 34 h exhibits the superior strength and ductility in this study.The ultimate tensile strength,tensile yield strength and elongation to failure,which is 455 MPa,308 MPa and 7.7%,respectively,are overall improved compared with the directly-aged(T5)sample.This paper provides a superior heat treatment schedule to manufacture high-performance large-scale Mg-Gd-Y-Zn-Zr-Ag components for industrial production.
文摘This paper addresses the decentralized consensus problem for a system of multiple dynamic agents with remote controllers via networking,known as a networked control multi-agent system(NCMAS).It presents a challenging scenario where partial dynamic entities or remote control units are vulnerable to disclosure attacks,making them potentially malicious.To tackle this issue,we propose a secure decentralized control design approach employing a double-layer cryptographic strategy.This approach not only ensures that the input and output information of the benign entities remains protected from the malicious entities but also practically achieves consensus performance.The paper provides an explicit design,supported by theoretical proof and numerical verification,covering stability,steady-state error,and the prevention of computation overflow or underflow.
基金Xin Chen,Chuming Liu,Yingchun Wan and Zhiyong Chen acknowledge National Natural Science Foundation of China(Grant number 51574291 and 51874367).
文摘A bulk nanocrystalline AZ31B Mg alloy with extraordinarily high strength was prepared via cryogenic rotary swaging in this study.The obtained alloy shows finer grains,higher strength,and a negligible tension-compression yield asymmetry,compared with that prepared via room-temperature rotary swaging.Transmission electron microscopy investigations showed that at the initial stage,multiple twins,mostly tension twins,were activated and intersected with each other,thereby refining the coarse grains into a fine lamellar structure.Then,two types of nanoscale subgrains were generated with increasing swaging strain.The first type of nanoscale subgrain contained twin boundaries and low-angle grain boundaries.This type of subgrain appeared at the twin-twin intersections and was mainly driven by high local stress.The second type of nanoscale subgrain was formed within the twin lamellae.The boundaries of this type of subgrain did not contain twin boundaries and were transformed from massive dislocation arrays.Finally,randomly oriented nanograins were obtained via dynamic recrystallization,under the combined function of deformation heat and increased stored energy.Compared with room-temperature rotary swaging,cryogenic rotary swaging exhibits a slower grain refinement process but a remarkably enhanced grain refinement effect after the same five-pass swaging.
基金the financial support from the National Natural Science Foundation of China(NSFC)with projects Nos.51874367,51574291.
文摘Mg-6.75Zn-0.57Zr-0.4Y-0.18Gd(wt.%)sheet with typical basal texture was produced by cross rolling and annealing.Room temperature tensile tests were subsequently conducted along rolling direction(RD),transverse direction(TD),and diagonal direction(RD45).Deformation mechanism and orientation evolution during the tension were investigated by quasi-in-situ electron backscatter diffraction observation and in-grain misorientation axis analysis.The results indicate that the activation of deformation mechanism mainly depends on the initial grain orientation.For RD sample,prismatic<a>slip plays an important role in the deformation of grains with<0001>axis nearly perpendicular to the RD.With the<0001>axis gradually tilted towards the RD,basal<a>slip becomes the dominant deformation mode.After the tensile fracture,the initial concentrically distributed{0001}pole is split into double peaks extending perpendicular to the RD,and the randomly distributed{1010}pole becomes parallel to the RD.The evolution in{0001}and{1010}poles during tension is related to the lattice rotation induced by basal<a>slip and prismatic<a>slip,respectively.TD and RD45 samples exhibit similar deformation mechanism and orientation evolution as the RD sample,which results in the nearly isotropic mechanical properties in the annealed cross-rolled sheet.
文摘Lipid peroxidation mediated by oxygen radical is one of the main mechanisms underlying secondary brain injury. Among all vitamin E compounds, α-tocopherol shows the most prominent antioxidative effects. It plays an important role in cell aging and injury. However, there has been no report regarding the effects of α-tocopherol on changes in brain tissue morphology after intracerebral hemorrhage (ICH), cerebral edema, or the expression of Bax and Bcl-2 proteins. We use SD rats to carry out the related studies;based on the atlas of SD rats, the caudate nucleus was positioned using a stereotaxic apparatus, and 50 μl autologous tail artery blood was injected to caudate nucleus in the ICH and α-tocopherol groups to establish ICH model. Rats in the sham surgery group received the same volume of saline in the caudate nucleus. Rats in the α-tocopherol group received intraperitoneal injections of α-tocopherol at 600 mg/kg every day. Rats in the ICH group and sham surgery group received the same amount of saline at the same times as those in the α-tocopherol group. We observed some interesting results: comparisons of brain tissue sections of rats from different groups showed that brain tissue damage and functional neurological deficits among rats from the α-tocopherol group were less pronounced than in the ICH group. Wet weight/ dry weight measurement showed that rats from the α-tocopherol group exhibited less cerebral edema than those in the ICH group. Rats from the α-tocopherol group showed less Bax expression and more Bcl-2 expression than those in the ICH group.
基金supported in part by National Natural Science Foundation of China(Grant No.61702149,U1709220)
文摘This paper considers a UAV communication system with mobile edge computing(MEC).We minimize the energy consumption of the whole system via jointly optimizing the UAV's trajectory and task assignment as well as CPU's computational speed under the set of resource constrains.To this end,we first derive the energy consumption model of data processing,and then obtain the energy consumption model of fixed-wing UAV's flight.The optimization problem is mathematically formulated.To address the problem,we first obtain the approximate optimization problem by applying the technique of discrete linear state-space approximation,and then transform the non-convex constraints into convex by using linearization.Furthermore,a concave-convex procedure(CCCP) based algorithm is proposed in order to solve the optimization problem approximately.Numerical results show the efficacy of the proposed algorithm.
基金supported by the National Natural Science Foundation of China(31570604,41371269)The Basal Research Fund of Fujian provincial Public Scientific Research Institution support(2014R1011-7)the Casuarina Research Center of Engineering and Technology,and the Key Laboratory of Forest Culture and Forest Product Processing Utilization of Fujian Province
文摘Trees on sand dunes are more sensitive to environmental changes because sandy soils have extremely low water holding capacity and nutrient availability. We investigated the dynamics of soil respiration(Rs) for secondary natural Litsea forest and plantations of casuarina,pine, acacia and eucalyptus. Results show that significant diurnal variations of Rsoccurred in autumn for the eucalyptus species and in summer for the pine species, with higher mean soil respiration at night. However, significant seasonal variations of Rswere found in all five forest stands. Rschanged exponentially with soil temperatures at the 10-cm depth; the models explain 43.3–77.0% of Rs variations. Positive relationships between seasonal Rsand soil moisture varied with stands. The correlations were significant only in the secondary forest, and the eucalyptus and pine plantations. The temperature sensitivity parameter(Q10 value) of Rsranged from 1.64 in casuarina plantation to 2.32 the in secondary forest; annual Rswas highest in the secondary forest and lowest in the pine plantation. The results indicate that soil temperatures and moisture are the primary environmental controls of soil respiration and mainly act through a direct influence on roots and microbial activity. Differences in root biomass, quality of litter,and soil properties(pH, total N, available P, and exchangeable Mg) were also significant factors.
基金The authors would like to thank Key Project of ChineseNational Programs for Fundamental Research and Develop-ment(973 program)National Natural Science Foundationof China(NSFC)through project nos.2013CB632202 and 51574291 respectivelythe outstanding graduate project ofAdvanced Non-ferrous Metal Structural Materials and Manu-facturing Collaborative Innovation Center.`
文摘The tensile deformation behavior and corresponding microstructure evolution of the Mg-4.7Gd-3.4Y-1.2Zn-0.5Zr(at.%)magnesium alloy with long period stacking structure(LPSO)are studied by electron backscatter diffraction(EBSD)and slip lines methods.The results show that less and very small size of twins is observed in the grains with high value of Schmid factor for twinning,which indicates that the growth of the{10–12}twinning deformation is prevented by the LPSO phase.The prismatic lines present in grains of which the prismatic slip Schmid factor is above 0.4.The favorable orientation and LPSO phase synergistically promote the activation of prismatic slip.The inhomogeneous rotation of the grains during deformation is the reason for the microcrack at grain boundary.
基金funded by the National Natural Science Foundation of China(3190020451 and 31771862)。
文摘Sugarcane is a prominent source of sugar and ethanol production.Genetic analysis for trait improvement of sugarcane is greatly hindered by its complex genome,long breeding cycle,and recalcitrance to genetic transformation.The protoplast-based transient transformation system is a versatile and convenient tool for in vivo functional gene analysis;however,quick and effective transformation systems are still lacking for sugarcane.Here,we developed an efficient protoplast-based transformation system by optimizing conditions of protoplasts isolation and PEG-mediated transformation in S.spontaneum.The yield of viable protoplasts was approximately 1.26×107 per gram of leaf material,and the transformation efficiency of 80.19%could be achieved under the optimized condition.Furthermore,using this approach,the nuclear localization of an ABI5-like bZIPs transcription factor was validated,and the promoter activity of several putative DNase I hypersensitive sites(DHSs)was assessed.The results indicated this system can be conveniently applied to protein subcellular localization and promoter activity assays.A highly efficient S.spontaneum mesophyll cell protoplast isolation and transient transformation method was developed,and it shall be suitable for in vivo functional gene analysis in sugarcane.
文摘In order to get the correct isotopic age, SHRIMP U-Pb zircon date of Precambrian hornblende granite in Well TD2, located in the central aeromagnetic belt in the eastern of the Tarim basin, was carried out. The result showed a dependable age of 1908.2 ± 8.6 Ma, which demonstrated that the granite pluton is the result of the magmatic activity in early Palaeoproterozoic. It is indicated that the central aeromagnetic belt across Tarim basin, divided it into north and south block, is formed before Neoproterozoic by a large scale tectonothermal events based on the seismic and drilling date. The Tarim continent may have different age and type basements formed the united crystalline basement in Precambrian. This result has yielded new intraplate evidence to constrain the relation between the Tarim plate and the Colombia supercontinent.
基金National Natural Science Foundation of China(51873079)for financial support。
文摘Simultaneous achievement in high solid content and high microsphere yield is deemed a challenge in the fabrication of monodisperse microspheres by precipitation polymerization.We herein demonstrate that micro-sized monodisperse poly(methacrylic monomer-divinylbenzene)microspheres containing epoxy,lauyl,carboxyl and hydroxyl functions can be fabricated by solvothermal precipitation copolymerization at 20%(mass)monomer loading with over 94%microsphere yield.The morphology and porosity of the obtained particles can be readily tuned by cosolvent-acetonitrile binary solvents.Addition of a small amount of cosolvent that has similar solubility parameter to that of the functional monomer can significantly improve the monodispersity of the obtained microspheres.When tetrahydrofuran was used as the co-solvent,the surface area of the highly porous microspheres achieved higher than 400 m^(2)·g^(-1).Solvothermal precipitation co-polymerization can be expected in scale-up fabrication of various monodisperse functional microspheres free of any surfactant and additive.
基金This work is supported by the Ministry of Education of China(MOE)-China Mobile Communication Corpo-ration(CMCC)Science Joint Foundation under grant MCM20180102.
文摘Motivated by 5th generation wireless systems(5G),a large number of emerging applications appear,which put forward higher requirements for the task’s transmission determinacy,which refers to the delay and jitter.To satisfy the deterministic requirement,mobile edge computing(MEC)is envisioned as a promising technique for reducing the end-to-end delay significantly.In this paper,we consider delaysensitive task and jitter-sensitive task,and then formulate the joint communications and computing optimization problem under the latency,the total bandwidth,the total transmission power of base station(BS)and the computing ability of the MEC server constraints to minimize the delay and jitter in a multiuser MEC system.Because of the problems are nonconvex,we decouple them into some subproblems and propose the corresponding algorithms to obtain a suboptimal solution.Finally,numerical results show that the proposed algorithms have a significant performance gain over the traditional solution in terms of the delay and the jitter.
文摘With the rapid development of smart terminals and infrastructures,as well as diversified applications(e.g.,autonomous driving,virtual and augmented reality,space-air-ground integrated networks)with colorful demands,current networks(e.g.,4G and 5G networks)may not be well suited to the requirements of novel applications and services.Recently,efforts from both the industry and academia have been made on the research into 6G networks,artificial intelligence(AI)will play a pivotal role in the design and optimization of 6G networks.
文摘The edge cache is an effective way to reduce the heavy traffic load and the end-to-end latency in radio access networks(RANs)for supporting a number of critical Internet of Things(IoT)services and applications.It has been verified to provide high spectral efficiency,high energy efficiency,and low latency.To exploit the advantages of edge cache,a paradigm of fog computing-based radio access networks(F-RANs)has emerged to provide great flexibility to satisfy quality-of-service requirements of various IoT applications in the fifth generation(5G)wireless systems.
基金supported by the National Key R&D Program of China(No.2021YFB3701100).
文摘The deformation mechanism,microstructure evolution,and precipitation behavior of a Mg-8.9Gd-1.8Y-0.5Zr-0.2Ag(wt.%)alloy multi-directionally forged at three different temperatures were investigated.As the forging temperature increases,the particle-stimulated nucleation(PSN)effect diminishes as the num-ber of dynamic precipitates decreases,pyramidal slip is activated,grain boundary migration accelerates,and continuous dynamic recrystallization(CDRX)dominates.The microstructures varied greatly,although fine-grained structures were formed at all different forging temperatures.Competitive precipitation be-tween dynamic precipitate growth,dislocation-induced precipitation,and homogeneous precipitation was observed after aging treatment.Among them,the medium temperature(748 K)forged and aged alloy ex-hibits the best mechanical performance,with an ultimate tensile strength of 436 MPa,and elongation of 16.3%.The calculation indicates that the mixed precipitation structure containing theβprecipitate band provides a 35%higher strengthening contribution than the typical homogeneously distributed precipi-tates.The formation of precipitation-free zones(PFZs)ensures that aging will not cause a dramatic de-crease in ductility,which provides a reference for the industrial preparation of high-performance wrought Mg-Gd series alloys.
基金National Nature Science Foundation of China(No.12074322,No.62072383)Science and Technology Project of Xiamen City(3502Z20183012)+1 种基金Science and Technology Planning Project of Guangdong Province(2018B030331001)Shenzhen Science and technology plan project(JCYJ20180504170208402)。
文摘A wearable sensing system that can reconstruct dynamic 3D human body models for virtual cloth fitting is highly important in the era of information and metaverse.However,few research has been conducted regarding conformal sen-sors for accurately measuring the human body circumferences for dynamic 3D human body reshaping.Here,we develop a stretchable spring-sheathed yarn sensor(SSYS)as a smart ruler,for precisely measuring the circumference of human bodies and long-term tracking the movement for the dynamic 3D body reconstruction.The SSYS has a robust property,high resilience,high stability(>18000),and ultrafast response(12 ms)to external deformation.It is also washable,wearable,tailorable,and durable for long-time wearing.Moreover,geometric,and mechanical behaviors of the SSYS are systematically investigated both theoretically and experimentally.In addition,a transfer learning algorithm that bridges the discrepancy of real and virtual sensing performance is devel-oped,enabling a small body circumference measurement error of 1.79%,notice-ably lower than that of traditional learning algorithm.Furtherly,3D human bodies that are numerically consistent with the actual bodies are reconstructed.The 3D dynamic human body reconstruction based on the wearing sensing sys-tem and transfer learning algorithm enables excellent virtual fitting and shirt customization in a smart and highly efficient manner.This wearable sensing technology shows great potential in human-computer interaction,intelligent fitting,specialized protection,sports activities,and human physiological health tracking.
基金the National Natural Science Foundation of China(2180212552074244)+2 种基金the Central Plains Science and Technology Innovation Leader Project(214200510006)Henan Outstanding Foreign Scientists,Workroom(GZS2018004)and the National Key R&D Program of China(2022YFC2104505)the Program of Henan Center for Oustanding Overseas Scientists(No.GZS2022007)for the financial support.
文摘Isomerization of glucose to fructose is a fundamental and key intermediate process commonly included in the production of valuable chemicals from carbohydrates in biorefinery.Enhancement of fructose yield is a challenge.In this work,Sn-doped silica nanotube(Sn-SNT)was developed as a highly efficient Lewis acid catalyst for the selective isomerization of glucose to fructose.Over Sn-SNT,69.1%fructose yield with 78.5%selectivity was obtained after reaction at 110◦C for 6 h.The sole presence of a large amount of Lewis acid sites in Sn-SNT without Brønsted acid site is one of the reasons for the high fructose yield and selectivity.Otherwise,high density of SiOH groups in Sn-SNT can ensure the presence of SiOH groups near the Sn sites,which is important for the isomerization of glucose to fructose,leading to the high fructose yield and selectivity.Furthermore,the Sn-SNT is recyclable.