Conventional seismic exploration method based on post-stack data usually fails to identify the distribution of fractured and caved carbonate reservoirs in the Tarim Basin,so the rich pre-stack information should be ap...Conventional seismic exploration method based on post-stack data usually fails to identify the distribution of fractured and caved carbonate reservoirs in the Tarim Basin,so the rich pre-stack information should be applied to the prediction of carbonate reservoirs.Amplitude-preserved seismic data processing is the foundation.In this paper,according to the feature of desert seismic data (including weak reflection,fast attenuation of high frequency components,strong coherent noises,low S/N and resolution),a set of amplitude-preserved processing techniques is applied and a reasonable processing flow is formed to obtain the high quality data.After implementing a set of pre-stack amplitude-preserved processing,we test and define the kernel parameters of amplitude-preserved Kirchhoff PSTM (pre-stack time migration) and subsequent gathers processing,in order to obtain the amplitude-preserved gathers used to the isotropic pre-stack inversion for the identification of caved reservoirs.The AVO characteristics of obtained gathers fit well with the synthetic gathers from logging data,and it proves that the processing above is amplitudepreserved.The azimuthal processing techniques,including azimuth division and binning enlargement,are implemented for amplitude-preserved azimuthal gathers with the uniform fold.They can be used in the anisotropic inversion to detect effective fractures.The processing techniques and flows are applied to the field seismic data,and are proved available for providing the amplitude-preserved gathers for carbonate reservoir prediction in the Tarim Basin.展开更多
Gas hydrate drilling expeditions in the Pearl River Mouth Basin,South China Sea,have identified concentrated gas hydrates with variable thickness.Moreover,free gas and the coexistence of gas hydrate and free gas have ...Gas hydrate drilling expeditions in the Pearl River Mouth Basin,South China Sea,have identified concentrated gas hydrates with variable thickness.Moreover,free gas and the coexistence of gas hydrate and free gas have been confirmed by logging,coring,and production tests in the foraminifera-rich silty sediments with complex bottom-simulating reflectors(BSRs).The broad-band processing is conducted on conventional three-dimensional(3D)seismic data to improve the image and detection accuracy of gas hydratebearing layers and delineate the saturation and thickness of gas hydrate-and free gas-bearing sediments.Several geophysical attributes extracted along the base of the gas hydrate stability zone are used to demonstrate the variable distribution and the controlling factors for the differential enrichment of gas hydrate.The inverted gas hydrate saturation at the production zone is over 40% with a thickness of 90 m,showing the interbedded distribution with different boundaries between gas hydrate-and free gas-bearing layers.However,the gas hydrate saturation value at the adjacent canyon is 70%,with 30-m-thick patches and linear features.The lithological and fault controls on gas hydrate and free gas distributions are demonstrated by tracing each gas hydrate-bearing layer.Moreover,the BSR depths based on broad-band reprocessed 3D seismic data not only exhibit variations due to small-scale topographic changes caused by seafloor sedimentation and erosion but also show the upward shift of BSR and the blocky distribution of the coexistence of gas hydrate and free gas in the Pearl River Mouth Basin.展开更多
The sensory perception of food is a dynamic process,which is closely related to the release of flavor substances during oral processing.It’s not only affected by the food material,but also subjected to the individual...The sensory perception of food is a dynamic process,which is closely related to the release of flavor substances during oral processing.It’s not only affected by the food material,but also subjected to the individual oral environment.To explore the oral processing characteristics of soft-boiled chicken,the sensory properties,texture,particle size,viscosity,characteristic values of electronic nose and tongue of different chicken samples were investigated.The correlation analysis showed that the physical characteristics especially the cohesiveness,springiness,resilience of the sample determined oral processing behavior.The addition of chicken skin played a role in lubrication during oral processing.The particle size of the bolus was heightened at the early stage,and the fluidity was enhanced in the end,which reduced the chewing time to the swallowing point and raised the aromatic compounds signal of electronic nose.But the effect of chicken skin on chicken thigh with relatively high fat content,was opposite in electronic nose,which had a certain masking effect on the perception of umami and sweet taste.In conclusion,fat played a critical role in chicken oral processing and chicken thigh had obvious advantages in comprehensive evaluation of soft-boiled chicken,which was more popular among people.展开更多
A large-scale fine-grained Mg-Gd-Y-Zn-Zr alloy plate with high strength and ductility was successfully prepared by multi-pass friction stir processing(MFSP)technology in this work.The structure of grains and long peri...A large-scale fine-grained Mg-Gd-Y-Zn-Zr alloy plate with high strength and ductility was successfully prepared by multi-pass friction stir processing(MFSP)technology in this work.The structure of grains and long period stacking ordered(LPSO)phase were characterized,and the mechanical properties uniformity was investigated.Moreover,a quantitative relationship between the microstructure and tensile yield strength was established.The results showed that the grains in the processed zone(PZ)and interfacial zone(IZ)were refined from 50μm to 3μm and 4μm,respectively,and numerous original LPSO phases were broken.In IZ,some block-shaped 18R LPSO phases were transformed into needle-like 14H LPSO phases due to stacking faults and the short-range diffusion of solute atoms.The severe shear deformation in the form of kinetic energy caused profuse stacking fault to be generated and move rapidly,greatly increasing the transformation rate of LPSO phase.After MFSP,the ultimate tensile strength,yield strength and elongation to failure of the large-scale plate were 367 MPa,305 MPa and 18.0% respectively.Grain refinement and LPSO phase strengthening were the major strengthening mechanisms for the MFSP sample.In particularly,the strength of IZ was comparable to that of PZ because the strength contribution of the 14H LPSO phase offsets the lack of grain refinement strengthening in IZ.This result opposes the widely accepted notion that IZ is a weak region in MFSP-prepared large-scale fine-grained plate.展开更多
An experiment was meticulously conducted at the research field of Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur, Bangladesh, during the 2011-2012 potato growing season to develop integrat...An experiment was meticulously conducted at the research field of Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur, Bangladesh, during the 2011-2012 potato growing season to develop integrated crop management practices for the potato seed production of industrial processing varieties Asterix and Courage. Significantly, higher growth and yield parameters were found in the BADC-recommended practice. Later, another experiment was conducted to validate the BADC practice during the 2013-2014 potato growing season in two locations in Bangladesh. Results showed that the production of tuber per hill, tuber weight per hill as well as gross tuber yield per plot, higher proportion of storable seed tubers, and more quality seed potatoes (A-grade and B-grade) seed tubers were found significantly higher in the “BADC developed practice” compared to other treatments. Viral diseases (PLRV and PVY) prevalence was lower in “BADC developed practice”. Moreover, “BADC developed practice” contributed more economic yield by minimizing input cost compared to “Munshiganj advanced farmers’ practice”. Therefore, the “BADC developed practice” was found “superior” regarding yield, quality, and profitability in seed potato production of industrial varieties—Asterix and Courage in Bangladesh.展开更多
The exponential growth of literature is constraining researchers’access to comprehensive information in related fields.While natural language processing(NLP)may offer an effective solution to literature classificatio...The exponential growth of literature is constraining researchers’access to comprehensive information in related fields.While natural language processing(NLP)may offer an effective solution to literature classification,it remains hindered by the lack of labelled dataset.In this article,we introduce a novel method for generating literature classification models through semi-supervised learning,which can generate labelled dataset iteratively with limited human input.We apply this method to train NLP models for classifying literatures related to several research directions,i.e.,battery,superconductor,topological material,and artificial intelligence(AI)in materials science.The trained NLP‘battery’model applied on a larger dataset different from the training and testing dataset can achieve F1 score of 0.738,which indicates the accuracy and reliability of this scheme.Furthermore,our approach demonstrates that even with insufficient data,the not-well-trained model in the first few cycles can identify the relationships among different research fields and facilitate the discovery and understanding of interdisciplinary directions.展开更多
Obesity and type 2 diabetes are widespread throughout the world, especially in developed countries. Starch is an important part of human staple food, the modulating of starch digestibility is conducive to reducing pos...Obesity and type 2 diabetes are widespread throughout the world, especially in developed countries. Starch is an important part of human staple food, the modulating of starch digestibility is conducive to reducing postprandial blood glucose levels and alleviating the chronic disease caused by high caloric intake. The digestion properties of starch are correlated with its structural features, including crystallization, amylose/amylopectin ratio, non-starch components, etc. Among the modified methods applied to regulate starch digestibility, non-thermal processing techniques(NTPT) receive extensive attention due to the characteristics of safety, environmental friendliness and high efficiency. The influence and mechanism of NTPT on the digestion properties of starch are discussed in this review, including ultrasounds, high pressure, γ-irradiation, etc. NTPT induces the alternation of morphological and structural characteristics of native starch, changing their sensitivity to enzymes. The effects of NTPT on the digestibility of starch are highly related to the processing parameters and structure characteristics of native starch. The review shows that NTPT is an effective way to modulate the digestion properties of starch and prevent people from suffering from chronic diseases such as obesity and type 2 diabetes.展开更多
[Objectives]To compare the effects of traditional processing and fresh processing on the quality of Polygonatum odoratum decoction piece.[Methods]The effects of fresh processing and traditional processing on the quali...[Objectives]To compare the effects of traditional processing and fresh processing on the quality of Polygonatum odoratum decoction piece.[Methods]The effects of fresh processing and traditional processing on the quality of P.odoratum decoction piece were compared and analyzed with appearance characteristics,total ash content,extract content,total polysaccharides content,and total flavonoids content as the evaluation indexes.[Results]Fresh processing method in different production areas has different effects on P.odoratum decoction piece.P.odoratum was dried in oven of 50℃.When moisture content was 41.44%-59.67%,it was cut.After complete drying at 50℃,the moisture content of dried P.odoratum was 8.94%-9.60%,and ethanol-soluble extract content was 77.29%-78.20%,and water-soluble extract was 77.7%-78.14%.At this time,the appearance characteristics of section of P.odoratum decoction piece were better than that of traditional processing,which was yellowish white.The total polysaccharide content was higher than that of traditional processing,and the content of total flavonoids was statistically significant different from that of traditional processing.[Conclusions]The quality of P.odoratum decoction piece by fresh processing is better than that of the traditional processing,and it is feasible to use fresh processing.展开更多
Beam-hopping technology has become one of the major research hotspots for satellite communication in order to enhance their communication capacity and flexibility.However,beam hopping causes the traditional continuous...Beam-hopping technology has become one of the major research hotspots for satellite communication in order to enhance their communication capacity and flexibility.However,beam hopping causes the traditional continuous time-division multiplexing signal in the forward downlink to become a burst signal,satellite terminal receivers need to solve multiple key issues such as burst signal rapid synchronization and high-per-formance reception.Firstly,this paper analyzes the key issues of burst communication for traffic signals in beam hopping sys-tems,and then compares and studies typical carrier synchro-nization algorithms for burst signals.Secondly,combining the requirements of beam-hopping communication systems for effi-cient burst and low signal-to-noise ratio reception of downlink signals in forward links,a decoding assisted bidirectional vari-able parameter iterative carrier synchronization technique is pro-posed,which introduces the idea of iterative processing into car-rier synchronization.Aiming at the technical characteristics of communication signal carrier synchronization,a new technical approach of bidirectional variable parameter iteration is adopted,breaking through the traditional understanding that loop struc-tures cannot adapt to low signal-to-noise ratio burst demodula-tion.Finally,combining the DVB-S2X standard physical layer frame format used in high throughput satellite communication systems,the research and performance simulation are con-ducted.The results show that the new technology proposed in this paper can significantly shorten the carrier synchronization time of burst signals,achieve fast synchronization of low signal-to-noise ratio burst signals,and have the unique advantage of flexible and adjustable parameters.展开更多
Glutinous rice(Oryza sativa var.glutinosa)stands out as one of the most popular rice varieties globally,amidst thousands of rice cultivars.Its increasing popularity is attributed to its rich nutritional compositions a...Glutinous rice(Oryza sativa var.glutinosa)stands out as one of the most popular rice varieties globally,amidst thousands of rice cultivars.Its increasing popularity is attributed to its rich nutritional compositions and health benefits.This review aims to summarize the nutritional compositions,volatile compounds,and health benefits of glutinous rice.Further,in-depth studies are necessary to explore the utilization of glutinous rice in enhancing processing technologies and developing new food products.Glutinous rice has been shown to possess numerous health benefits,including antioxidant activity,bioactive compounds,anti-cancer properties,anti-inflammatory effects,anti-diabetic potential,and cholesterol-lowering effects.Besides its nutritional compositions,the major volatile compounds identified in glutinous rice could serve as a functional food for human consumption.Emerging processing technologies related to glutinous rice are elaborated to improve the latest developments for incorporating them into various food products.展开更多
Nowadays,magnesium alloys are emerging in biomedical implants for their similar properties to natural bones.However,the rapid degradation of magnesium alloys in biological media hinders successful implantation.Refinem...Nowadays,magnesium alloys are emerging in biomedical implants for their similar properties to natural bones.However,the rapid degradation of magnesium alloys in biological media hinders successful implantation.Refinement of microstructure,as well as reinforcement particles can significantly improve the degradation rate.In this work,multi-pass friction stir processing(FSP)was proposed to synthesize WE43/nano-hydroxyapatite(n HA)surface composite,the microstructure,reinforced particle distribution,micro-hardness,corrosion behavior and in-vitro bioactivity were studied.The subsequent FSP passes of WE43 alloy and WE43/n HA composite refined the grain size which was reduced by 94.29%and 95.92%(2.63 and 1.88μm,respectively)compared to base metal after three passes.This resulted in increasing the microhardness by 120%(90.86 HV0.1)and 135%(105.59 HV0.1)for the WE43 and WE43-n HA,respectively.It is found that increasing FSP passes improved the uniform distribution of n HA particles within the composite matrix which led to improved corrosion resistance and less degradation rate.The corrosion rate of the FSPed WE43/n HA composite after three passes was reduced by 38.2%(4.13 mm/year)and the degradation rate was reduced by 69.7%(2.87 mm/y).This is attributed to secondary phase(Mg24Y5and Mg41Nd5)particle fragmentation and redistribution,as well as a homogeneous distribution of n HA.Additionally,the growing Ca-P and Mg(OH)2layer formed on the surface represented a protective layer that reduced the degradation rate.The wettability test revealed a relatively hydrophilic surface with water contact angle of 49.1±2.2°compared to 71.2±2.1°for base metal.Also,biomineralization test showed that apatite layer grew after immersion 7d in simulated body fluid with atomic ratio of Ca/P 1.60 approaching the stoichiometric ratio(1.67)indicating superior bioactivity of FSPed WE43/n HA composite after three passes.These results raise that the grain refinement by FSP and introduction of n HA particles significantly improved the degradation rate and in-vitro bioactivity of WE43 alloy for biomedical applications.展开更多
Constructing the magnesium alloy with fine grains,low density of dislocations,and weak crystal orientation is of crucial importance to enhance its comprehensive performance as the anode for Mg-air battery.However,this...Constructing the magnesium alloy with fine grains,low density of dislocations,and weak crystal orientation is of crucial importance to enhance its comprehensive performance as the anode for Mg-air battery.However,this unique microstructure can hardly be achieved with conventional plastic deformation such as rolling or extrusion.Herein,we tailor the microstructure of Mg-Al-Sn-RE alloy by using the friction stir processing,which obviously refines the grains without increasing dislocation density or strengthening crystal orientation.The Mg-air battery with the processed Mg-Al-Sn-RE alloy as the anode exhibits higher discharge voltages and capacities than that employing the untreated anode.Furthermore,the impact of friction stir processing on the electrochemical discharge behaviour of Mg-Al-Sn-RE anode and the corresponding mechanism are also analysed according to microstructure characterization and electrochemical response.展开更多
A novel method for noise removal from the rotating accelerometer gravity gradiometer(MAGG)is presented.It introduces a head-to-tail data expansion technique based on the zero-phase filtering principle.A scheme for det...A novel method for noise removal from the rotating accelerometer gravity gradiometer(MAGG)is presented.It introduces a head-to-tail data expansion technique based on the zero-phase filtering principle.A scheme for determining band-pass filter parameters based on signal-to-noise ratio gain,smoothness index,and cross-correlation coefficient is designed using the Chebyshev optimal consistent approximation theory.Additionally,a wavelet denoising evaluation function is constructed,with the dmey wavelet basis function identified as most effective for processing gravity gradient data.The results of hard-in-the-loop simulation and prototype experiments show that the proposed processing method has shown a 14%improvement in the measurement variance of gravity gradient signals,and the measurement accuracy has reached within 4E,compared to other commonly used methods,which verifies that the proposed method effectively removes noise from the gradient signals,improved gravity gradiometry accuracy,and has certain technical insights for high-precision airborne gravity gradiometry.展开更多
Mg–3Nd–0.2Zn–0.4Zr(NZ30K,wt.%)alloy is a new kind of high-performance metallic biomaterial.The combination of the NZ30K Magnesium(Mg)alloy and selective laser melting(SLM)process seems to be an ideal solution to pr...Mg–3Nd–0.2Zn–0.4Zr(NZ30K,wt.%)alloy is a new kind of high-performance metallic biomaterial.The combination of the NZ30K Magnesium(Mg)alloy and selective laser melting(SLM)process seems to be an ideal solution to produce porous Mg degradable implants.However,the microstructure evolution and mechanical properties of the SLMed NZ30K Mg alloy were not yet studied systematically.Therefore,the fabrication defects,microstructure,and mechanical properties of the SLMed NZ30K alloy under different processing parameters were investigated.The results show that there are two types of fabrication defects in the SLMed NZ30K alloy,gas pores and unfused defects.With the increase of the laser energy density,the porosity sharply decreases to the minimum first and then slightly increases.The minimum porosity is 0.49±0.18%.While the microstructure varies from the large grains with lamellar structure inside under low laser energy density,to the large grains with lamellar structure inside&the equiaxed grains&the columnar grains under middle laser energy density,and further to the fine equiaxed grains&the columnar grains under high laser energy density.The lamellar structure in the large grain is a newly observed microstructure for the NZ30K Mg alloy.Higher laser energy density leads to finer grains,which enhance all the yield strength(YS),ultimate tensile strength(UTS)and elongation,and the best comprehensive mechanical properties obtained are YS of 266±2.1 MPa,UTS of 296±5.2 MPa,with an elongation of 4.9±0.68%.The SLMed NZ30K Mg alloy with a bimodal-grained structure consisting of fine equiaxed grains and coarser columnar grains has better elongation and a yield drop phenomenon.展开更多
Rising concerns about climate change drive the demand for lightweight components.Magnesium(Mg)alloys are highly valued for their low weight,making them increasingly important in various industries.Researchers focusing...Rising concerns about climate change drive the demand for lightweight components.Magnesium(Mg)alloys are highly valued for their low weight,making them increasingly important in various industries.Researchers focusing on enhancing the characteristics of Mg alloys and developing their Metal Matrix Composites(MMCs)have gained significant attention worldwide over the past decade,driven by the global shift towards lightweight materials.Friction Stir Processing(FSP)has emerged as a promising technique to enhance the properties of Mg alloys and produce Mg-MMCs.Initially,FSP adapted to refine grain size from the micro to the nano level and accelerated the development of MMCs due to its solid-state nature and the synergistic effects of microstructure refinement and reinforcement,improving strength,hardness,ductility,wear resistance,corrosion resistance,and fatigue strength.However,producing defect-free and sound FSPed Mg and Mg-MMCs requires addressing several variables and their interdependencies,which opens up a broad range of practical applications.Despite existing reviews on individual FSP of Mg,its alloys,and MMCs,an attempt has been made to analyze the latest research on these three aspects collectively to enhance the understanding,application,and effectiveness of FSP for Mg and its derivatives.This review article discusses the literature,classifies the importance of Mg alloys,provides a historical background,and explores developments and potential applications of FSPed Mg alloys.It focuses on novel fabrication methods,reinforcement strategies,machine and tool design parameters,material characterization,and integration with other methods for enhanced properties.The influence of process parameters and the emergence of defects are examined,along with specific applications in mono and hybrid composites and their microstructure evolution.The study identifies promising reinforcement materials and highlights research gaps in FSP for Mg alloys and MMCs production.It concludes with significant recommendations for further exploration,reflecting ongoing advancements in this field.展开更多
SIL1,an endoplasmic reticulum(ER)-resident protein,is reported to play a protective role in Alzheimer’s disease(AD).However,the effect of SIL1 on amyloid precursor protein(APP)processing remains unclear.In this study...SIL1,an endoplasmic reticulum(ER)-resident protein,is reported to play a protective role in Alzheimer’s disease(AD).However,the effect of SIL1 on amyloid precursor protein(APP)processing remains unclear.In this study,the role of SIL1 in APP processing was explored both in vitro and in vivo.In the in vitro experiment,SIL1 was either overexpressed or knocked down in cells stably expressing the human Swedish mutant APP695.In the in vivo experiment,AAV-SIL1-EGFP or AAV-EGFP was microinjected into APP23/PS45 mice and their wild-type littermates.Western blotting(WB),immunohistochemistry,RNA sequencing(RNA-seq),and behavioral experiments were performed to evaluate the relevant parameters.Results indicated that SIL1 expression decreased in APP23/PS45 mice.Overexpression of SIL1 significantly decreased the protein levels of APP,presenilin-1(PS1),and C-terminal fragments(CTFs)of APP in vivo and in vitro.Conversely,knockdown of SIL1 increased the protein levels of APP,β-site APP cleavage enzyme 1(BACE1),PS1,and CTFs,as well as APP mRNA expression in 2EB2 cells.Furthermore,SIL1 overexpression reduced the number of senile plaques in APP23/PS45 mice.Importantly,Y-maze and Morris Water maze tests demonstrated that SIL1 overexpression improved cognitive impairment in APP23/PS45 mice.These findings indicate that SIL1 improves cognitive impairment in APP23/PS45 mice by inhibiting APP amyloidogenic processing and suggest that SIL1 is a potential therapeutic target for AD by modulating APP processing.展开更多
In the digital era,emojis have enriched the way people communicate and research on emojis explosively increased in recent years.However,few noticed their functions from the neurocognitive perspective,especially their ...In the digital era,emojis have enriched the way people communicate and research on emojis explosively increased in recent years.However,few noticed their functions from the neurocognitive perspective,especially their similarities and differences with facial expressions in traditional face-to-face communication.To fill this gap,we conducted a Meta-analysis with 25 independent effect sizes from previous experimental studies.The present study shows that emojis have slight advantages in processing efficiency,which might be attributed to their simplicity in design,namely the omission of complex facial features,but the difference between emoji and face processing is not significant.In addition,emotional valence and experimental methods do not have significant influences,which suggests that emojis are equally effective as human faces in emotional expression.The current research contributes to the knowledge in digital communication and the crucial role played by emojis therein.展开更多
Food allergens are mainly naturally-occurring proteins with immunoglobulin E(IgE)-binding epitopes.Understanding the structural and immunogenic characteristics of allergenic proteins is essential in assessing whether ...Food allergens are mainly naturally-occurring proteins with immunoglobulin E(IgE)-binding epitopes.Understanding the structural and immunogenic characteristics of allergenic proteins is essential in assessing whether and how food processing techniques reduce allergenicity.We here discuss the impacts of food processing technologies on the modification of physicochemical,structural,and immunogenic properties of allergenic proteins.Detection techniques for characterizing changes in these properties of food allergens are summarized.Food processing helps to reduce allergenicity by aggregating or denaturing proteins,which masks,modifies,or destroys antigenic epitopes,whereas,it cannot eliminate allergenicity completely,and sometimes even improves allergenicity by exposing new epitopes.Moreover,most food processing techniques have been tested on purified food allergens rather than food products due to potential interference of other food components.We provide guidance for further development of processing operations that can decrease the allergenicity of allergenic food proteins without negatively impacting the nutritional profile.展开更多
Due to the restricted satellite payloads in LEO mega-constellation networks(LMCNs),remote sensing image analysis,online learning and other big data services desirably need onboard distributed processing(OBDP).In exist...Due to the restricted satellite payloads in LEO mega-constellation networks(LMCNs),remote sensing image analysis,online learning and other big data services desirably need onboard distributed processing(OBDP).In existing technologies,the efficiency of big data applications(BDAs)in distributed systems hinges on the stable-state and low-latency links between worker nodes.However,LMCNs with high-dynamic nodes and long-distance links can not provide the above conditions,which makes the performance of OBDP hard to be intuitively measured.To bridge this gap,a multidimensional simulation platform is indispensable that can simulate the network environment of LMCNs and put BDAs in it for performance testing.Using STK's APIs and parallel computing framework,we achieve real-time simulation for thousands of satellite nodes,which are mapped as application nodes through software defined network(SDN)and container technologies.We elaborate the architecture and mechanism of the simulation platform,and take the Starlink and Hadoop as realistic examples for simulations.The results indicate that LMCNs have dynamic end-to-end latency which fluctuates periodically with the constellation movement.Compared to ground data center networks(GDCNs),LMCNs deteriorate the computing and storage job throughput,which can be alleviated by the utilization of erasure codes and data flow scheduling of worker nodes.展开更多
基金financially supported by National Basic Research Program of China(No.2011CB201100)
文摘Conventional seismic exploration method based on post-stack data usually fails to identify the distribution of fractured and caved carbonate reservoirs in the Tarim Basin,so the rich pre-stack information should be applied to the prediction of carbonate reservoirs.Amplitude-preserved seismic data processing is the foundation.In this paper,according to the feature of desert seismic data (including weak reflection,fast attenuation of high frequency components,strong coherent noises,low S/N and resolution),a set of amplitude-preserved processing techniques is applied and a reasonable processing flow is formed to obtain the high quality data.After implementing a set of pre-stack amplitude-preserved processing,we test and define the kernel parameters of amplitude-preserved Kirchhoff PSTM (pre-stack time migration) and subsequent gathers processing,in order to obtain the amplitude-preserved gathers used to the isotropic pre-stack inversion for the identification of caved reservoirs.The AVO characteristics of obtained gathers fit well with the synthetic gathers from logging data,and it proves that the processing above is amplitudepreserved.The azimuthal processing techniques,including azimuth division and binning enlargement,are implemented for amplitude-preserved azimuthal gathers with the uniform fold.They can be used in the anisotropic inversion to detect effective fractures.The processing techniques and flows are applied to the field seismic data,and are proved available for providing the amplitude-preserved gathers for carbonate reservoir prediction in the Tarim Basin.
基金supported by the State Key Laboratory of Natural Gas Hydrate(No.2022-KFJJ-SHW)the National Natural Science Foundation of China(No.42376058)+2 种基金the International Science&Technology Cooperation Program of China(No.2023YFE0119900)the Hainan Province Key Research and Development Project(No.ZDYF2024GXJS002)the Research Start-Up Funds of Zhufeng Scholars Program.
文摘Gas hydrate drilling expeditions in the Pearl River Mouth Basin,South China Sea,have identified concentrated gas hydrates with variable thickness.Moreover,free gas and the coexistence of gas hydrate and free gas have been confirmed by logging,coring,and production tests in the foraminifera-rich silty sediments with complex bottom-simulating reflectors(BSRs).The broad-band processing is conducted on conventional three-dimensional(3D)seismic data to improve the image and detection accuracy of gas hydratebearing layers and delineate the saturation and thickness of gas hydrate-and free gas-bearing sediments.Several geophysical attributes extracted along the base of the gas hydrate stability zone are used to demonstrate the variable distribution and the controlling factors for the differential enrichment of gas hydrate.The inverted gas hydrate saturation at the production zone is over 40% with a thickness of 90 m,showing the interbedded distribution with different boundaries between gas hydrate-and free gas-bearing layers.However,the gas hydrate saturation value at the adjacent canyon is 70%,with 30-m-thick patches and linear features.The lithological and fault controls on gas hydrate and free gas distributions are demonstrated by tracing each gas hydrate-bearing layer.Moreover,the BSR depths based on broad-band reprocessed 3D seismic data not only exhibit variations due to small-scale topographic changes caused by seafloor sedimentation and erosion but also show the upward shift of BSR and the blocky distribution of the coexistence of gas hydrate and free gas in the Pearl River Mouth Basin.
基金supported by China Agriculture Research System of MOF and MARA(CARS-41)Wens Fifth Five R&D Major Project(WENS-2020-1-ZDZX-007)。
文摘The sensory perception of food is a dynamic process,which is closely related to the release of flavor substances during oral processing.It’s not only affected by the food material,but also subjected to the individual oral environment.To explore the oral processing characteristics of soft-boiled chicken,the sensory properties,texture,particle size,viscosity,characteristic values of electronic nose and tongue of different chicken samples were investigated.The correlation analysis showed that the physical characteristics especially the cohesiveness,springiness,resilience of the sample determined oral processing behavior.The addition of chicken skin played a role in lubrication during oral processing.The particle size of the bolus was heightened at the early stage,and the fluidity was enhanced in the end,which reduced the chewing time to the swallowing point and raised the aromatic compounds signal of electronic nose.But the effect of chicken skin on chicken thigh with relatively high fat content,was opposite in electronic nose,which had a certain masking effect on the perception of umami and sweet taste.In conclusion,fat played a critical role in chicken oral processing and chicken thigh had obvious advantages in comprehensive evaluation of soft-boiled chicken,which was more popular among people.
基金supported by the National Key Research and Development Program of China(2021YFB3501002)State Key Program of National Natural Science Foundation of China(5203405)+3 种基金National Natural Science Foundation of China(51974220,52104383)National Key Research and Development Program of China(2021YFB3700902)Key Research and Development Program of Shaanxi Province(2020ZDLGY13-06,2017ZDXM-GY-037)Shaanxi Province National Science Fund for Distinguished Young Scholars(2022JC-24)。
文摘A large-scale fine-grained Mg-Gd-Y-Zn-Zr alloy plate with high strength and ductility was successfully prepared by multi-pass friction stir processing(MFSP)technology in this work.The structure of grains and long period stacking ordered(LPSO)phase were characterized,and the mechanical properties uniformity was investigated.Moreover,a quantitative relationship between the microstructure and tensile yield strength was established.The results showed that the grains in the processed zone(PZ)and interfacial zone(IZ)were refined from 50μm to 3μm and 4μm,respectively,and numerous original LPSO phases were broken.In IZ,some block-shaped 18R LPSO phases were transformed into needle-like 14H LPSO phases due to stacking faults and the short-range diffusion of solute atoms.The severe shear deformation in the form of kinetic energy caused profuse stacking fault to be generated and move rapidly,greatly increasing the transformation rate of LPSO phase.After MFSP,the ultimate tensile strength,yield strength and elongation to failure of the large-scale plate were 367 MPa,305 MPa and 18.0% respectively.Grain refinement and LPSO phase strengthening were the major strengthening mechanisms for the MFSP sample.In particularly,the strength of IZ was comparable to that of PZ because the strength contribution of the 14H LPSO phase offsets the lack of grain refinement strengthening in IZ.This result opposes the widely accepted notion that IZ is a weak region in MFSP-prepared large-scale fine-grained plate.
文摘An experiment was meticulously conducted at the research field of Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur, Bangladesh, during the 2011-2012 potato growing season to develop integrated crop management practices for the potato seed production of industrial processing varieties Asterix and Courage. Significantly, higher growth and yield parameters were found in the BADC-recommended practice. Later, another experiment was conducted to validate the BADC practice during the 2013-2014 potato growing season in two locations in Bangladesh. Results showed that the production of tuber per hill, tuber weight per hill as well as gross tuber yield per plot, higher proportion of storable seed tubers, and more quality seed potatoes (A-grade and B-grade) seed tubers were found significantly higher in the “BADC developed practice” compared to other treatments. Viral diseases (PLRV and PVY) prevalence was lower in “BADC developed practice”. Moreover, “BADC developed practice” contributed more economic yield by minimizing input cost compared to “Munshiganj advanced farmers’ practice”. Therefore, the “BADC developed practice” was found “superior” regarding yield, quality, and profitability in seed potato production of industrial varieties—Asterix and Courage in Bangladesh.
基金funded by the Informatization Plan of Chinese Academy of Sciences(Grant No.CASWX2021SF-0102)the National Key R&D Program of China(Grant Nos.2022YFA1603903,2022YFA1403800,and 2021YFA0718700)+1 种基金the National Natural Science Foundation of China(Grant Nos.11925408,11921004,and 12188101)the Chinese Academy of Sciences(Grant No.XDB33000000)。
文摘The exponential growth of literature is constraining researchers’access to comprehensive information in related fields.While natural language processing(NLP)may offer an effective solution to literature classification,it remains hindered by the lack of labelled dataset.In this article,we introduce a novel method for generating literature classification models through semi-supervised learning,which can generate labelled dataset iteratively with limited human input.We apply this method to train NLP models for classifying literatures related to several research directions,i.e.,battery,superconductor,topological material,and artificial intelligence(AI)in materials science.The trained NLP‘battery’model applied on a larger dataset different from the training and testing dataset can achieve F1 score of 0.738,which indicates the accuracy and reliability of this scheme.Furthermore,our approach demonstrates that even with insufficient data,the not-well-trained model in the first few cycles can identify the relationships among different research fields and facilitate the discovery and understanding of interdisciplinary directions.
基金financial supported by the Program of the National Natural Science Foundation of China (31972034)the National Youth Top-notch Talent Support Program of China (201902)。
文摘Obesity and type 2 diabetes are widespread throughout the world, especially in developed countries. Starch is an important part of human staple food, the modulating of starch digestibility is conducive to reducing postprandial blood glucose levels and alleviating the chronic disease caused by high caloric intake. The digestion properties of starch are correlated with its structural features, including crystallization, amylose/amylopectin ratio, non-starch components, etc. Among the modified methods applied to regulate starch digestibility, non-thermal processing techniques(NTPT) receive extensive attention due to the characteristics of safety, environmental friendliness and high efficiency. The influence and mechanism of NTPT on the digestion properties of starch are discussed in this review, including ultrasounds, high pressure, γ-irradiation, etc. NTPT induces the alternation of morphological and structural characteristics of native starch, changing their sensitivity to enzymes. The effects of NTPT on the digestibility of starch are highly related to the processing parameters and structure characteristics of native starch. The review shows that NTPT is an effective way to modulate the digestion properties of starch and prevent people from suffering from chronic diseases such as obesity and type 2 diabetes.
基金Supported by Guangxi Science and Technology Major Project(GUIKE AA22096020)Central Guidance for Local Scientific and Technological Development Funds(ZY20230102)+2 种基金Guilin City Science Research and Technology Development Plan Project(20220104-4,20210202-1,2020011203-1,2020011203-2)Open Project of Guangxi Key Laboratory of Tumor Immunology and Microenvironment Regulation(2022KF005)College Students Innovative Entrepreneurial Training Plan Program(202210601015).
文摘[Objectives]To compare the effects of traditional processing and fresh processing on the quality of Polygonatum odoratum decoction piece.[Methods]The effects of fresh processing and traditional processing on the quality of P.odoratum decoction piece were compared and analyzed with appearance characteristics,total ash content,extract content,total polysaccharides content,and total flavonoids content as the evaluation indexes.[Results]Fresh processing method in different production areas has different effects on P.odoratum decoction piece.P.odoratum was dried in oven of 50℃.When moisture content was 41.44%-59.67%,it was cut.After complete drying at 50℃,the moisture content of dried P.odoratum was 8.94%-9.60%,and ethanol-soluble extract content was 77.29%-78.20%,and water-soluble extract was 77.7%-78.14%.At this time,the appearance characteristics of section of P.odoratum decoction piece were better than that of traditional processing,which was yellowish white.The total polysaccharide content was higher than that of traditional processing,and the content of total flavonoids was statistically significant different from that of traditional processing.[Conclusions]The quality of P.odoratum decoction piece by fresh processing is better than that of the traditional processing,and it is feasible to use fresh processing.
基金This work was supported by the Key Research and Development Program of Shaanxi(2022ZDLGY05-08)the Application Innovation Program of CASC(China Aerospace Science and Technology Corporation)(6230107001)+2 种基金the Research Project on Civil Aerospace Technology(D040304)the Research Project of CAST(Y23-WYHXJS-07)the Research Foundation of the Key Laboratory of Spaceborne Information Intelligent Interpretation(2022-ZZKY-JJ-20-01).
文摘Beam-hopping technology has become one of the major research hotspots for satellite communication in order to enhance their communication capacity and flexibility.However,beam hopping causes the traditional continuous time-division multiplexing signal in the forward downlink to become a burst signal,satellite terminal receivers need to solve multiple key issues such as burst signal rapid synchronization and high-per-formance reception.Firstly,this paper analyzes the key issues of burst communication for traffic signals in beam hopping sys-tems,and then compares and studies typical carrier synchro-nization algorithms for burst signals.Secondly,combining the requirements of beam-hopping communication systems for effi-cient burst and low signal-to-noise ratio reception of downlink signals in forward links,a decoding assisted bidirectional vari-able parameter iterative carrier synchronization technique is pro-posed,which introduces the idea of iterative processing into car-rier synchronization.Aiming at the technical characteristics of communication signal carrier synchronization,a new technical approach of bidirectional variable parameter iteration is adopted,breaking through the traditional understanding that loop struc-tures cannot adapt to low signal-to-noise ratio burst demodula-tion.Finally,combining the DVB-S2X standard physical layer frame format used in high throughput satellite communication systems,the research and performance simulation are con-ducted.The results show that the new technology proposed in this paper can significantly shorten the carrier synchronization time of burst signals,achieve fast synchronization of low signal-to-noise ratio burst signals,and have the unique advantage of flexible and adjustable parameters.
基金the Ministry of Higher Education,Malaysia for financial support via the Transdisciplinary Research Grant Scheme Project(Grant No.TRGS/1/2020/UPM/02/7)。
文摘Glutinous rice(Oryza sativa var.glutinosa)stands out as one of the most popular rice varieties globally,amidst thousands of rice cultivars.Its increasing popularity is attributed to its rich nutritional compositions and health benefits.This review aims to summarize the nutritional compositions,volatile compounds,and health benefits of glutinous rice.Further,in-depth studies are necessary to explore the utilization of glutinous rice in enhancing processing technologies and developing new food products.Glutinous rice has been shown to possess numerous health benefits,including antioxidant activity,bioactive compounds,anti-cancer properties,anti-inflammatory effects,anti-diabetic potential,and cholesterol-lowering effects.Besides its nutritional compositions,the major volatile compounds identified in glutinous rice could serve as a functional food for human consumption.Emerging processing technologies related to glutinous rice are elaborated to improve the latest developments for incorporating them into various food products.
基金supported by the University Malaya(Grant code:FRGS/1/2022/TK10/UM/02/6)the National Natural Science Foundation of China(Grant No.51275414,No.51605387)Deanship of Scientific Research at King Khalid University for funding this work through the Large Groups Project under grant number RGP.2/303/44。
文摘Nowadays,magnesium alloys are emerging in biomedical implants for their similar properties to natural bones.However,the rapid degradation of magnesium alloys in biological media hinders successful implantation.Refinement of microstructure,as well as reinforcement particles can significantly improve the degradation rate.In this work,multi-pass friction stir processing(FSP)was proposed to synthesize WE43/nano-hydroxyapatite(n HA)surface composite,the microstructure,reinforced particle distribution,micro-hardness,corrosion behavior and in-vitro bioactivity were studied.The subsequent FSP passes of WE43 alloy and WE43/n HA composite refined the grain size which was reduced by 94.29%and 95.92%(2.63 and 1.88μm,respectively)compared to base metal after three passes.This resulted in increasing the microhardness by 120%(90.86 HV0.1)and 135%(105.59 HV0.1)for the WE43 and WE43-n HA,respectively.It is found that increasing FSP passes improved the uniform distribution of n HA particles within the composite matrix which led to improved corrosion resistance and less degradation rate.The corrosion rate of the FSPed WE43/n HA composite after three passes was reduced by 38.2%(4.13 mm/year)and the degradation rate was reduced by 69.7%(2.87 mm/y).This is attributed to secondary phase(Mg24Y5and Mg41Nd5)particle fragmentation and redistribution,as well as a homogeneous distribution of n HA.Additionally,the growing Ca-P and Mg(OH)2layer formed on the surface represented a protective layer that reduced the degradation rate.The wettability test revealed a relatively hydrophilic surface with water contact angle of 49.1±2.2°compared to 71.2±2.1°for base metal.Also,biomineralization test showed that apatite layer grew after immersion 7d in simulated body fluid with atomic ratio of Ca/P 1.60 approaching the stoichiometric ratio(1.67)indicating superior bioactivity of FSPed WE43/n HA composite after three passes.These results raise that the grain refinement by FSP and introduction of n HA particles significantly improved the degradation rate and in-vitro bioactivity of WE43 alloy for biomedical applications.
基金The Authors acknowledge the financial support of the National Nature Science Foundation of China(No.52171067)the Natural Science Foundation of Guangdong Province of China(No.2022A1515012366).
文摘Constructing the magnesium alloy with fine grains,low density of dislocations,and weak crystal orientation is of crucial importance to enhance its comprehensive performance as the anode for Mg-air battery.However,this unique microstructure can hardly be achieved with conventional plastic deformation such as rolling or extrusion.Herein,we tailor the microstructure of Mg-Al-Sn-RE alloy by using the friction stir processing,which obviously refines the grains without increasing dislocation density or strengthening crystal orientation.The Mg-air battery with the processed Mg-Al-Sn-RE alloy as the anode exhibits higher discharge voltages and capacities than that employing the untreated anode.Furthermore,the impact of friction stir processing on the electrochemical discharge behaviour of Mg-Al-Sn-RE anode and the corresponding mechanism are also analysed according to microstructure characterization and electrochemical response.
文摘A novel method for noise removal from the rotating accelerometer gravity gradiometer(MAGG)is presented.It introduces a head-to-tail data expansion technique based on the zero-phase filtering principle.A scheme for determining band-pass filter parameters based on signal-to-noise ratio gain,smoothness index,and cross-correlation coefficient is designed using the Chebyshev optimal consistent approximation theory.Additionally,a wavelet denoising evaluation function is constructed,with the dmey wavelet basis function identified as most effective for processing gravity gradient data.The results of hard-in-the-loop simulation and prototype experiments show that the proposed processing method has shown a 14%improvement in the measurement variance of gravity gradient signals,and the measurement accuracy has reached within 4E,compared to other commonly used methods,which verifies that the proposed method effectively removes noise from the gradient signals,improved gravity gradiometry accuracy,and has certain technical insights for high-precision airborne gravity gradiometry.
基金financial supports from the National Natural Science Foundation of China(52130104,51821001)High Technology and Key Development Project of Ningbo,China(2019B10102)。
文摘Mg–3Nd–0.2Zn–0.4Zr(NZ30K,wt.%)alloy is a new kind of high-performance metallic biomaterial.The combination of the NZ30K Magnesium(Mg)alloy and selective laser melting(SLM)process seems to be an ideal solution to produce porous Mg degradable implants.However,the microstructure evolution and mechanical properties of the SLMed NZ30K Mg alloy were not yet studied systematically.Therefore,the fabrication defects,microstructure,and mechanical properties of the SLMed NZ30K alloy under different processing parameters were investigated.The results show that there are two types of fabrication defects in the SLMed NZ30K alloy,gas pores and unfused defects.With the increase of the laser energy density,the porosity sharply decreases to the minimum first and then slightly increases.The minimum porosity is 0.49±0.18%.While the microstructure varies from the large grains with lamellar structure inside under low laser energy density,to the large grains with lamellar structure inside&the equiaxed grains&the columnar grains under middle laser energy density,and further to the fine equiaxed grains&the columnar grains under high laser energy density.The lamellar structure in the large grain is a newly observed microstructure for the NZ30K Mg alloy.Higher laser energy density leads to finer grains,which enhance all the yield strength(YS),ultimate tensile strength(UTS)and elongation,and the best comprehensive mechanical properties obtained are YS of 266±2.1 MPa,UTS of 296±5.2 MPa,with an elongation of 4.9±0.68%.The SLMed NZ30K Mg alloy with a bimodal-grained structure consisting of fine equiaxed grains and coarser columnar grains has better elongation and a yield drop phenomenon.
文摘Rising concerns about climate change drive the demand for lightweight components.Magnesium(Mg)alloys are highly valued for their low weight,making them increasingly important in various industries.Researchers focusing on enhancing the characteristics of Mg alloys and developing their Metal Matrix Composites(MMCs)have gained significant attention worldwide over the past decade,driven by the global shift towards lightweight materials.Friction Stir Processing(FSP)has emerged as a promising technique to enhance the properties of Mg alloys and produce Mg-MMCs.Initially,FSP adapted to refine grain size from the micro to the nano level and accelerated the development of MMCs due to its solid-state nature and the synergistic effects of microstructure refinement and reinforcement,improving strength,hardness,ductility,wear resistance,corrosion resistance,and fatigue strength.However,producing defect-free and sound FSPed Mg and Mg-MMCs requires addressing several variables and their interdependencies,which opens up a broad range of practical applications.Despite existing reviews on individual FSP of Mg,its alloys,and MMCs,an attempt has been made to analyze the latest research on these three aspects collectively to enhance the understanding,application,and effectiveness of FSP for Mg and its derivatives.This review article discusses the literature,classifies the importance of Mg alloys,provides a historical background,and explores developments and potential applications of FSPed Mg alloys.It focuses on novel fabrication methods,reinforcement strategies,machine and tool design parameters,material characterization,and integration with other methods for enhanced properties.The influence of process parameters and the emergence of defects are examined,along with specific applications in mono and hybrid composites and their microstructure evolution.The study identifies promising reinforcement materials and highlights research gaps in FSP for Mg alloys and MMCs production.It concludes with significant recommendations for further exploration,reflecting ongoing advancements in this field.
基金National Natural Science Foundation of China(82230043,82293642)。
文摘SIL1,an endoplasmic reticulum(ER)-resident protein,is reported to play a protective role in Alzheimer’s disease(AD).However,the effect of SIL1 on amyloid precursor protein(APP)processing remains unclear.In this study,the role of SIL1 in APP processing was explored both in vitro and in vivo.In the in vitro experiment,SIL1 was either overexpressed or knocked down in cells stably expressing the human Swedish mutant APP695.In the in vivo experiment,AAV-SIL1-EGFP or AAV-EGFP was microinjected into APP23/PS45 mice and their wild-type littermates.Western blotting(WB),immunohistochemistry,RNA sequencing(RNA-seq),and behavioral experiments were performed to evaluate the relevant parameters.Results indicated that SIL1 expression decreased in APP23/PS45 mice.Overexpression of SIL1 significantly decreased the protein levels of APP,presenilin-1(PS1),and C-terminal fragments(CTFs)of APP in vivo and in vitro.Conversely,knockdown of SIL1 increased the protein levels of APP,β-site APP cleavage enzyme 1(BACE1),PS1,and CTFs,as well as APP mRNA expression in 2EB2 cells.Furthermore,SIL1 overexpression reduced the number of senile plaques in APP23/PS45 mice.Importantly,Y-maze and Morris Water maze tests demonstrated that SIL1 overexpression improved cognitive impairment in APP23/PS45 mice.These findings indicate that SIL1 improves cognitive impairment in APP23/PS45 mice by inhibiting APP amyloidogenic processing and suggest that SIL1 is a potential therapeutic target for AD by modulating APP processing.
基金supported by Science Foundation of China University of Petroleum,Beijing(No.2462023YXZZ006)Undergraduate Key Teaching Reform Project(30GK2312).
文摘In the digital era,emojis have enriched the way people communicate and research on emojis explosively increased in recent years.However,few noticed their functions from the neurocognitive perspective,especially their similarities and differences with facial expressions in traditional face-to-face communication.To fill this gap,we conducted a Meta-analysis with 25 independent effect sizes from previous experimental studies.The present study shows that emojis have slight advantages in processing efficiency,which might be attributed to their simplicity in design,namely the omission of complex facial features,but the difference between emoji and face processing is not significant.In addition,emotional valence and experimental methods do not have significant influences,which suggests that emojis are equally effective as human faces in emotional expression.The current research contributes to the knowledge in digital communication and the crucial role played by emojis therein.
基金supported by the National Natural Science Foundation of China (32102605)the Agricultural Science and Technology Innovation Program under Grant (CAAS-ASTIP-2020IAR)the Earmarked Fund for CARS (CARS-44)。
文摘Food allergens are mainly naturally-occurring proteins with immunoglobulin E(IgE)-binding epitopes.Understanding the structural and immunogenic characteristics of allergenic proteins is essential in assessing whether and how food processing techniques reduce allergenicity.We here discuss the impacts of food processing technologies on the modification of physicochemical,structural,and immunogenic properties of allergenic proteins.Detection techniques for characterizing changes in these properties of food allergens are summarized.Food processing helps to reduce allergenicity by aggregating or denaturing proteins,which masks,modifies,or destroys antigenic epitopes,whereas,it cannot eliminate allergenicity completely,and sometimes even improves allergenicity by exposing new epitopes.Moreover,most food processing techniques have been tested on purified food allergens rather than food products due to potential interference of other food components.We provide guidance for further development of processing operations that can decrease the allergenicity of allergenic food proteins without negatively impacting the nutritional profile.
基金supported by National Natural Sciences Foundation of China(No.62271165,62027802,62201307)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515030297)+2 种基金the Shenzhen Science and Technology Program ZDSYS20210623091808025Stable Support Plan Program GXWD20231129102638002the Major Key Project of PCL(No.PCL2024A01)。
文摘Due to the restricted satellite payloads in LEO mega-constellation networks(LMCNs),remote sensing image analysis,online learning and other big data services desirably need onboard distributed processing(OBDP).In existing technologies,the efficiency of big data applications(BDAs)in distributed systems hinges on the stable-state and low-latency links between worker nodes.However,LMCNs with high-dynamic nodes and long-distance links can not provide the above conditions,which makes the performance of OBDP hard to be intuitively measured.To bridge this gap,a multidimensional simulation platform is indispensable that can simulate the network environment of LMCNs and put BDAs in it for performance testing.Using STK's APIs and parallel computing framework,we achieve real-time simulation for thousands of satellite nodes,which are mapped as application nodes through software defined network(SDN)and container technologies.We elaborate the architecture and mechanism of the simulation platform,and take the Starlink and Hadoop as realistic examples for simulations.The results indicate that LMCNs have dynamic end-to-end latency which fluctuates periodically with the constellation movement.Compared to ground data center networks(GDCNs),LMCNs deteriorate the computing and storage job throughput,which can be alleviated by the utilization of erasure codes and data flow scheduling of worker nodes.