[Objectives]This study was conducted to isolate and identify the components from stems of Polyalthia plagioneura.[Methods]The compounds were isolated and purified by silica gel column,Sephadex LH-20,and C_(18) chromat...[Objectives]This study was conducted to isolate and identify the components from stems of Polyalthia plagioneura.[Methods]The compounds were isolated and purified by silica gel column,Sephadex LH-20,and C_(18) chromatography.Their chemical structures were elucidated on the basis of physicochemical properties and spectral data.[Results]Five compounds were isolated and identified as:di(2-ethylhexyl)phthalate(1),cinnamic anhydride(2),phthalic acid(3),citric acid(4),and syringaldehyde(5).[Conclusions]All compounds were isolated from this plant for the first time.展开更多
The commercial AM60(Mg−6Al−0.3Mn)die-casting alloy was modified through Mn,Ce,and La micro-alloying,each at a content below 0.2 wt.%.SEM,TEM,and Micro-CT were employed to characterize the microstructures and propertie...The commercial AM60(Mg−6Al−0.3Mn)die-casting alloy was modified through Mn,Ce,and La micro-alloying,each at a content below 0.2 wt.%.SEM,TEM,and Micro-CT were employed to characterize the microstructures and properties of AM60 based alloys.AM60-0.2La alloy showed excellent mechanical properties.The ultimate tensile strength,yield strength,and elongation of(288.0±1.7)MPa,(158.0±1.0)MPa,and(22.0±3.0)%were achieved in AM60-0.2La alloy.Besides,AM60-0.2La alloy exhibited the best corrosion resistance(0.29 mm/a)and fluidity among the investigated four alloys.The excellent mechanical properties and corrosion resistance are mainly attributed to the grain refinement strengthening,low porosity,and low content of large shrinkage porosity,promising for super-sized integrated automotive components.展开更多
Enhancing the resilience of critical infrastructure(CI)systems has become a focal point of national and inter-national policies.However,the formulation of resilience enhancement strategies often requires component-(i....Enhancing the resilience of critical infrastructure(CI)systems has become a focal point of national and inter-national policies.However,the formulation of resilience enhancement strategies often requires component-(i.e.asset-)level prioritization,which entails many complexities.Acknowledging the complex and interdependent nature of infrastructure systems,this paper aims to aid researchers,practitioners and policy-makers by pre-senting a review of the relative literature and current state-of-the-art,and by identifying future research op-portunities to improve the applicability and operationalizability of CI component identification and prioritization methods.Theoretical and practical applications are reviewed for definitions,analysis and modelling approaches regarding the resilience of interdependent infrastructure systems.A detailed review of infrastructure criticality definitions,component criticality assessment and prioritization frameworks,from scientific,policy and other documents,is presented.A discussion on social justice and equity dimensions therein is included,which have the potential to greatly influence decisions and should always be incorporated in infrastructure planning and in-vestment discussions.The findings of this review are discussed in terms of applicability and operationalizability.Key recommendations for future research include:(i)developing quantification frameworks for CI component criticality based on formal definitions and multiple criteria,(ii)incorporating the entire resilience cycle of CI in component prioritization,(iii)accounting for the socio-technical nature of CI systems by integrating social di-mensions and their wider operating environment and(iv)developing comprehensive model validation,cali-bration and uncertainty analysis frameworks.展开更多
In aerospace,nuclear power,and new energy vehicles industries,utilizing integrated metal components with extreme sizes and/or structures is crucial for achieving significant weight-saving,performance-improvement,and e...In aerospace,nuclear power,and new energy vehicles industries,utilizing integrated metal components with extreme sizes and/or structures is crucial for achieving significant weight-saving,performance-improvement,and excellent reliability.These components,made from metal sheets,rings,or tubes,exhibit characteristics like ultra-thin,ultra-thick,ultra-large,ultra-long,ultra-high ribs,and large variable diameters.During plastic de-formation in metal forming processes,defects such as ruptures,wrinkles,excessive strain differences,and un-expected weak performance areas are likely to occur due to the intersection of multiple effects in different research disciplines,including materials science,processes,and mechanics of materials.Consequently,the smooth forming of integrated parts is difficult.It is the first time to review,summarize,and analyze the ad-vancement of forming methods for producing integrated parts with extreme sizes and structures.The general academic ideas to change the process conditions and sequences to optimize stress state and improve plastic deformation ability for forming the components with extreme sizes/structures are introduced.Practical ex-amples,discussed in detail in the paper,include the forming of(i)integrated ultra-thin and ultra-thick sheet components;(ii)integrated ultra-large size ring components with thin wall and high ribs;and(iii)integrated ultra-long tube components with large perimeter difference.Various plasticity technologies and process se-quences have been developed.The key processes and applications of the technologies are discussed in detail,which achieve successful plastic forming of integrated components.This paper provides state-of-the-art and perspectives for the rapidly advancing material forming fields of key metal components for the next generation of equipment.展开更多
The goal of the present work is to demonstrate the potential of Artificial Neural Network(ANN)-driven Genetic Algorithm(GA)methods for energy efficiency and economic performance optimization of energy efficiency measu...The goal of the present work is to demonstrate the potential of Artificial Neural Network(ANN)-driven Genetic Algorithm(GA)methods for energy efficiency and economic performance optimization of energy efficiency measures in a multi-family house building in Greece.The energy efficiency measures include different heating/cooling systems(such as low-temperature and high-temperature heat pumps,natural gas boilers,split units),building envelope components for floor,walls,roof and windows of variable heat transfer coefficients,the installation of solar thermal collectors and PVs.The calculations of the building loads and investment and operating and maintenance costs of the measures are based on the methodology defined in Directive 2010/31/EU,while economic assumptions are based on EN 15459-1 standard.Typically,multi-objective optimization of energy efficiency measures often requires the simulation of very large numbers of cases involving numerous possible combinations,resulting in intense computational load.The results of the study indicate that ANN-driven GA methods can be used as an alternative,valuable tool for reliably predicting the optimal measures which minimize primary energy consumption and life cycle cost of the building with greatly reduced computational requirements.Through GA methods,the computational time needed for obtaining the optimal solutions is reduced by 96.4%-96.8%.展开更多
电子元器件种类繁多且没有一致的细粒度分类标准,为快速满足元器件在不同粒度下的分类需求,提出一种基于深度学习的YOLOR-ECA(YOLOv8 and ResNet50 with efficient channel attention)电子元器件检测算法。首先采用YOLOv8网络定位元器...电子元器件种类繁多且没有一致的细粒度分类标准,为快速满足元器件在不同粒度下的分类需求,提出一种基于深度学习的YOLOR-ECA(YOLOv8 and ResNet50 with efficient channel attention)电子元器件检测算法。首先采用YOLOv8网络定位元器件位置,然后采用ResNet50网络对定位获取的元器件进行识别分类,通过元器件种类的增减满足不同细粒度的分类标准。为提升模型对尺寸小、特征相似元器件的细节特征提取能力,分类网络引入ECA注意力机制,并对残差结构的捷径连接部分进行改进;为避免神经元失活,采用GELU(Gaussian Error Linear Units)激活函数。实验结果表明,改进的YOLOR-ECA模型的检测准确率为96.6%,并且对于小尺寸元器件的识别精度最高可达100%,对于具有特征相似性元器件的误检率最低可降到0.01%,能实现电子元器件在不同细粒度分类标准下的高效检测。展开更多
AIM:To investigate the effect of severe acute pan- creatitis(SAP)on pharmacokinetics of Da-Cheng-Qi Decoction(DCQD)components in rats. METHODS:Rats were divided into SAP group and sham-operation group as a control gro...AIM:To investigate the effect of severe acute pan- creatitis(SAP)on pharmacokinetics of Da-Cheng-Qi Decoction(DCQD)components in rats. METHODS:Rats were divided into SAP group and sham-operation group as a control group(n=6). Rhein,chrysophanol,rheochrysidin,magnolol,hesperidin and naringin in DCQD were quantified in rat serum by high performance liquid chromatography tandem mass spectrometry for studying their pharmacokinetics. RESULTS:Early absorption of each DCQD component was tended to degrade in SAP group after treatment with DCQD by gavage.The Cmax(chrysophanol,P= 0.0059;rheochrysidin,P=0.0288;magnolol,P= 0.0487;hesperidin,P=0.0277;naringin,P=0.0023) and AUC(rhein,P=0.0186;chrysophanol,P=0.0013; magnolol,P=0.001;hesperidin,P=0.0081;naringin, P=0.0272)of DCQD component were obviously lower in SAP group than in control group.The T1/2α of chrysophanol and rheochrysidin(P=0.0467 and 0.0005,respectively)and Tmax of chrysophanol and rheochrysidin(P=0.0101 and 0.0037,respectively) lasted longer in SAP group than in control group. CONCLUSION:SAP can significantly impact the ab-sorption of DCQD components in rats and their phar-macokinetic parameters.展开更多
Studying the topology of infrastructure communication networks(e.g., the Internet) has become a means to understand and develop complex systems. Therefore, investigating the evolution of Internet network topology migh...Studying the topology of infrastructure communication networks(e.g., the Internet) has become a means to understand and develop complex systems. Therefore, investigating the evolution of Internet network topology might elucidate disciplines governing the dynamic process of complex systems. It may also contribute to a more intelligent communication network framework based on its autonomous behavior. In this paper, the Internet Autonomous Systems(ASes) topology from 1998 to 2013 was studied by deconstructing and analysing topological entities on three different scales(i.e., nodes,edges and 3 network components: single-edge component M1, binary component M2 and triangle component M3). The results indicate that: a) 95% of the Internet edges are internal edges(as opposed to external and boundary edges); b) the Internet network consists mainly of internal components, particularly M2 internal components; c) in most cases, a node initially connects with multiple nodes to form an M2 component to take part in the network; d) the Internet network evolves to lower entropy. Furthermore, we find that, as a complex system, the evolution of the Internet exhibits a behavioral series,which is similar to the biological phenomena concerned with the study on metabolism and replication. To the best of our knowledge, this is the first study of the evolution of the Internet network through analysis of dynamic features of its nodes,edges and components, and therefore our study represents an innovative approach to the subject.展开更多
Albiziae Flos(AF)has been experimentally proven to have an antidepressant effect.However,due to the complexity of botanical ingredients,the exact pharmacological mechanism of action of AF in depression has not been co...Albiziae Flos(AF)has been experimentally proven to have an antidepressant effect.However,due to the complexity of botanical ingredients,the exact pharmacological mechanism of action of AF in depression has not been completely deciphered.This study used the network pharmacology method to construct a component-target-pathway network to explore the active components and potential mechanisms of action of AF.The methods included collection and screening of chemical components,prediction of depression-associated targets of the active components,gene enrichment,and network construction and analysis.Quercetin and 4 other active components were found to exert an tidepressant effects mainly via monoaminergic neurotransmitters and cAMP signaling and neuroactive ligand・wceptor interaction pathways.DRD2,HTR1 A,and SLC6A4 were identified as important targets of the studied bioactive components of AF.This network pharmacology analysis provides guidance for further study of the antidepressant mechanism of AF.展开更多
Resynthesized rapeseeds obtained by crossing the diploid parents Brassica rapa and Brassica oleracea have significant potential in hybrid breeding because of their higher genetic basis compared with Brassica napus cul...Resynthesized rapeseeds obtained by crossing the diploid parents Brassica rapa and Brassica oleracea have significant potential in hybrid breeding because of their higher genetic basis compared with Brassica napus cultivars. In this study, an 8 × 8 complete diallel experiment using four B. napus cultivars （BN） and four resynthesized rapeseed lines （RS） as parents was designed to study heterosis and genetic inheritance for yield components. The results showed that heterosis for yield per plant, the number of pods per plant and number of seeds per pod were high, with means 32.77, 24.49 and 15.71%, respectively. Diallel analysis showed that both additive and dominant effects were significant for yield and yield components. All traits, except for 1 000-seed weight, were significant for bl mean squares and exhibited directional dominance. Dominant genes had positive effects on yield per plant, pods per plant and 1000-seed weight, and negative effects on seeds per pod （r=-0.86, -0.62, -0.41, and 0.47, respectively）. Narrow-sense heritability for yield per plant, pods per plant, and 1 000-seed weight and seeds per pod were 66, 31, 46 and 78% for the four traits, respectively. The Fl hybrids showed considerable yields compared to B. napus cultivars when B. napus cultivars and resynthesized rapeseeds were used as parents （NR hybrids）, with many more pods per plant and lower seeds per pod compared with the rapeseed cultivars, indicating that the resynthesized rapeseed may be applicable in current hybrid breeding programs.展开更多
A combined model based on principal components analysis (PCA) and generalized regression neural network (GRNN) was adopted to forecast electricity price in day-ahead electricity market. PCA was applied to mine the mai...A combined model based on principal components analysis (PCA) and generalized regression neural network (GRNN) was adopted to forecast electricity price in day-ahead electricity market. PCA was applied to mine the main influence on day-ahead price, avoiding the strong correlation between the input factors that might influence electricity price, such as the load of the forecasting hour, other history loads and prices, weather and temperature; then GRNN was employed to forecast electricity price according to the main information extracted by PCA. To prove the efficiency of the combined model, a case from PJM (Pennsylvania-New Jersey-Maryland) day-ahead electricity market was evaluated. Compared to back-propagation (BP) neural network and standard GRNN, the combined method reduces the mean absolute percentage error about 3%.展开更多
The use of waste crumb rubber powder as a modifier for modified asphalt can recycle waste rubber to ease pressure on the environment and improve the performance of asphalt. Diffusion of components of asphalt into wast...The use of waste crumb rubber powder as a modifier for modified asphalt can recycle waste rubber to ease pressure on the environment and improve the performance of asphalt. Diffusion of components of asphalt into waste rubber is of vital importance to improve the performance of rubber modified asphalt,while the related researches are scarce. Diffusion of components of asphalt into waste rubber at different temperatures has been investigated in this work. Rectangle rubber was immersed in asphalt at certain temperature for a period of time. And the mass increment of rubber was measured to determine the diffusion rate of components of asphalt into rubber. The experimental results indicated that the diffusion rate of components of asphalt into waste rubber increases along the temperature,but the diffusion rate of components of fractions oil which is distillated from catalytic cracking slurry is much higher than that of components of asphalt. Compared with asphalt,fractions oil enjoys lower viscosity and better permeability with higher content of saturates and aromatics. All the characteristics are contributed to the efficient diffusion of components of fractions into waste rubber.展开更多
The genetic analysis of soybean isoflavone content and its components were carried out based on the NC Ⅱ matingdesign in eight soybean varieties. The results showed that the isoflavone contents and its components of ...The genetic analysis of soybean isoflavone content and its components were carried out based on the NC Ⅱ matingdesign in eight soybean varieties. The results showed that the isoflavone contents and its components of soybean seedare quite differences among the tested materials, the contents of isoflavone and daidzein are controlled not only byadditive effects and but also by non-additive effects, while the content of genistin is dominated by non-additive effects,and genistein, glycitin and daidzin are mainly controlled by additive effects. There are significant differences in thecontents of isoflavone and its components among the combinations derived from different parents. Results also indicatedthat the tested traits are negatively heterosis except for the contens of daidzein and daidzin are positively heterosis basedon the data of the GCA and SCA in average heterosis values. In this research we have a suggestion that soybean varietywith high isoflavone should be used as one of the parents in the breeding program, and it is the best choice that thecombinations crossed between two high isoflavone varieties or a high variety and a low one.展开更多
Objective:To explore the network control mechanism of the calcium signaling pathway in cerebral ischemic injury after intervention by the main components of Qingkailing(清开灵),i.e.Baicalin,Jasminoidin and their combi...Objective:To explore the network control mechanism of the calcium signaling pathway in cerebral ischemic injury after intervention by the main components of Qingkailing(清开灵),i.e.Baicalin,Jasminoidin and their combination.Methods:Thirty mice were randomly divided into 5 groups,a baicalin group,a Jasminoidin group,a baicalin plus Jasminoidin group,a nimodipine group,and a model group(n=6).The global cerebral ischemia-reperfusion mouse model was established.The mice were administrated respectively by injection of baicalin,Jasminoidin,mixture of baicalin and Jasminoidin,and nimodipine into the caudal vein,with the model group given no any drug.Three hours after operation,the brain was removed and sectioned.After calculation of cerebral ischemic area by 2,3,5-triphenyltetrazolium staining,the percentage of infarct volume was calculated.The total RNA of the mouse brain tissue was extracted to obtain the whole genome expression profile,and the differentially expressed genes related to the calcium signaling pathway was analyzed with Bayesian network structures.Results:Compared with the model group,the ischemic area was significantly reduced in the baicalin group,the Jasminoidin group,the Baicalin plus Jasminoidin group(all P<0.05).The ischemic area in the baicalin plus Jasminoidin group was smaller than the other three groups(all P<0.01).In the gene regulatory network structures of calcium signaling pathway,the average length and equitability were the highest in the baicalin plus Jasminoidin group,followed by the nimodipine group.Conclusion:Compared with a single component,combination of Baicalin and Jasminoidin can more obviously intervene in the overall expression of calcium signaling pathway,and the mechanism is related with the aggregation characteristic of the gene expression network.展开更多
Magneto-mechanical coupling vibration arises in the in-vessel components of Tokamak devices especially during the plasma disruption. Strong electromagnetic forces cause the structures to vibrate while the motion in tu...Magneto-mechanical coupling vibration arises in the in-vessel components of Tokamak devices especially during the plasma disruption. Strong electromagnetic forces cause the structures to vibrate while the motion in turn changes the distribution of the electromagnetic field. To ensure the Tokamak devices operating in a designed state, numerical analysis on the coupling vibration is of great importance. This paper introduces two numerical methods for the magneto-mechanical coupling problems. The coupling term of velocity and magnetic flux density is manipulated in both Eulerian and Lagrangian description, which brings much simplification in numerical implementation. Corresponding numerical codes have been developed and applied to the dynamic simulation of a test module in J-TEXT and the vacuum vessel of HL-2M during plasma disruptions. The results reveal the evident influence of the magnetic stiffness and magnetic damping effects on the vibration behavior of the in-vessel structures. Finally, to deal with the halo current injection problem, a numerical scheme is described and validated which can simulate the distribution of the halo current without complicated manipulations.展开更多
AIM: To investigate the metabolic profiles of xenograft pancreatic cancer before and after radiotherapy by high-resolution magic angle spinning proton magnetic resonance spectroscopy (HRMAS 1H NMR) combined with princ...AIM: To investigate the metabolic profiles of xenograft pancreatic cancer before and after radiotherapy by high-resolution magic angle spinning proton magnetic resonance spectroscopy (HRMAS 1H NMR) combined with principal components analysis (PCA) and evaluate the radiotherapeutic effect. METHODS: The nude mouse xenograft model of human pancreatic cancer was established by injecting human pancreatic cancer cell SW1990 subcutaneously into the nude mice. When the tumors volume reached 800 mm3 , the mice received various radiation doses. Two weeks later, tumor tissue sections were prepared for running the NMR measurements. 1H NMR and PCA were used to determine the changes in the metabolic profiles of tumor tissues after radiotherapy. Metabolic profiles of normal pancreas, pancreatic tumor tissues, and radiationtreated pancreatic tumor tissues were compared. RESULTS: Compared with 1H NMR spectra of the normal nude mouse pancreas, the levels of choline, taurine, alanine, isoleucine, leucine, valine, lactate, and glutamic acid of the pancreatic cancer group were increased, whereas an opposite trend for phosphocholine, glycerophosphocholine, and betaine was observed. The ratio of phosphocholine to creatine, and glycerophosphocholine to creatine showed noticeable decrease in the pancreatic cancer group. After further evaluation of the tissue metabolic profile after treatment with three different radiation doses, no significant change in metabolites was observed in the 1H NMR spectra, while the inhibition of tumor growth was in proportion to the radiation doses. However, PCA results showed that the levels of choline and betaine were decreased with the increased radiation dose, and conversely, the level of acetic acid was dramatically increased. CONCLUSION: The combined methods were demonstrated to have the potential for allowing early diagnosis and assessment of pancreatic cancer response to radiotherapy.展开更多
Machining performance of thin-walled components made by aeronautical difficult-toprocess materials is a significant issue in the aviation manufacturing industry.Although wire electric discharge machining-low speed(WED...Machining performance of thin-walled components made by aeronautical difficult-toprocess materials is a significant issue in the aviation manufacturing industry.Although wire electric discharge machining-low speed(WEDM-LS)is one of typical non-contact machining processes without macro cutting force,which does well in removing hardness and brittleness materials via pulsed discharge at high temperature,but few researchers have studied the thermal distortion behavior leading to a considerable geometric error in the WEDM-LS of thin-walled components.In this paper,a transverse magnetic field assisted method is applied for affecting the uniformity of discharge point distribution so as to reduce the distortion in WEDM-LS processing thin-wall component.First,the generation mechanism of this new distortion behavior and the impact mechanism of transverse magnetic field(TMF)on distortion are demonstrated by theoretical analysis.In order to further figure out the distortion behavior in the TMF-WEDM process,a new thermophysical model considering the discharge point distribution is established to simulate temperature field,residual stress field and distortion profiles.Then a large number of Taguchi experiments are carried out to investigate the influences of process parameters including pulse discharge energy(pulse on time,pulse off time,and current)and magnetic field strength on distortion in WEDM-LS.To comparatively analyze simulated and experimental results,the accuracy of established thermophysical model is verified within a relative error of 18.38%in distortion.Moreover,it can be revealed that transverse magnetic field contribute to significantly improve the longitudinal distribution uniformity with maximum increase of 12.32%at magnetic field strength:0.15 T,leading to significant reductions of 32.77%in distortion and 22.68%in recast layer.Eventually,we also presented the variation of residual stress and recast layer along thickness direction under different distortion behavior,which are in good agreement with that of distortion behavior.展开更多
Association analysis provides an opportunity to find genetic variants underlying complex traits. A principal components regression （PCR）-based approach was shown to outperform some competing approaches. However, a l...Association analysis provides an opportunity to find genetic variants underlying complex traits. A principal components regression （PCR）-based approach was shown to outperform some competing approaches. However, a limitation of this method is that the principal components （PCs） selected from single nucleotide polyrnorphisms （SNPs） may be unrelated to the phenotype. In this article, we investigate the theoretical properties of such a method in more detail. We first derive the exact power function of the test based on PCR, and hence clarify the relationship between the test power and the degrees of freedom （DF）. Next, we extend the PCR test to a general weighted PCs test, which provides a unified framework for understanding the properties of some related statistics. We then compare the performance of these tests. We also introduce several data-driven adaptive alternatives to overcome difficulties in the PCR approach. Finally, we illustrate our results using simulations based on real genotype data. Simulation study shows the risk of using the unsupervised rule to determine the number of PCs, and demonstrates that there is no single uniformly powerful method for detecting genetic variants.展开更多
The tin(Sn)-tungsten(W)polymetallic ore concentrated district in SE Yunnan is distributed at the junction region of the Yangtze Block,the Cathaysian Block and the Indosinian Block,where there are several giant deposit...The tin(Sn)-tungsten(W)polymetallic ore concentrated district in SE Yunnan is distributed at the junction region of the Yangtze Block,the Cathaysian Block and the Indosinian Block,where there are several giant deposits of tin,tungsten,copper,silver,lead,zinc and indium closely associated with a large scale Late Cretaceous magmatism.Bi-dimensional empirical mode decomposition(BEMD)is used to extract aeromagnetic anomalous components at the survey scale of 1:200000 from the original aeromagnetic data of SE Yunnan.Four intrinsic mode functions(IMFs)and a residues component are obtained,which may reflect the geological structures and geological bodies at different spatial scales from high frequency to low frequency.The results are shown as follows:(1)Two different types of Precambrian basement in the study area were recognized:one is the Yangtze Block basement characterized by a strong positive magnetic anomaly,the other is the Cathaysian Block basement with a weak negative magnetic anomaly.The former consists of high grade metamorphic rocks including metamorphosed basic igneous rocks,while the latter consists of low grade metamorphosed sedimentary rocks.(2)The aeromagnetic anomalies associated with Sn-W polymetallic mineralization and related to granites in the study area illustrate a pattern of a skarnized alteration-mineralization zone with a positive ring magnetic anomaly enclosing a granitic intrusion with negative magnetic anomaly;(3)The ring positive magnetic anomaly zones enclosing the negative magnetic anomaly are defined as the SnW polymetallic ore-searching targets in the study area.展开更多
基金Supported by Jiangxi Education Department Project(GJJ201533)University-level Project of Gannan Medical University(YB201902).
文摘[Objectives]This study was conducted to isolate and identify the components from stems of Polyalthia plagioneura.[Methods]The compounds were isolated and purified by silica gel column,Sephadex LH-20,and C_(18) chromatography.Their chemical structures were elucidated on the basis of physicochemical properties and spectral data.[Results]Five compounds were isolated and identified as:di(2-ethylhexyl)phthalate(1),cinnamic anhydride(2),phthalic acid(3),citric acid(4),and syringaldehyde(5).[Conclusions]All compounds were isolated from this plant for the first time.
基金financially supported by the National Key Research and Development Program of China(Nos.2022YFB3709300,2021YFB3701000)the National Natural Science Foundation of China(Nos.52271090,52071036,U2037601,U21A2048)+1 种基金Chongqing Science and Technology Commission,China(Nos.CSTB2022TIAD-KPX0021,CSTC2024YCJHBGZXM0164,CSTB2024TIAD-KPX0001)the Fundamental Research Funds for the Central Universities,China(No.2022CDJDX-002)。
文摘The commercial AM60(Mg−6Al−0.3Mn)die-casting alloy was modified through Mn,Ce,and La micro-alloying,each at a content below 0.2 wt.%.SEM,TEM,and Micro-CT were employed to characterize the microstructures and properties of AM60 based alloys.AM60-0.2La alloy showed excellent mechanical properties.The ultimate tensile strength,yield strength,and elongation of(288.0±1.7)MPa,(158.0±1.0)MPa,and(22.0±3.0)%were achieved in AM60-0.2La alloy.Besides,AM60-0.2La alloy exhibited the best corrosion resistance(0.29 mm/a)and fluidity among the investigated four alloys.The excellent mechanical properties and corrosion resistance are mainly attributed to the grain refinement strengthening,low porosity,and low content of large shrinkage porosity,promising for super-sized integrated automotive components.
基金supported by the European Union’s Horizon 2020 research and innovation programme under grant agreement No.101037424.
文摘Enhancing the resilience of critical infrastructure(CI)systems has become a focal point of national and inter-national policies.However,the formulation of resilience enhancement strategies often requires component-(i.e.asset-)level prioritization,which entails many complexities.Acknowledging the complex and interdependent nature of infrastructure systems,this paper aims to aid researchers,practitioners and policy-makers by pre-senting a review of the relative literature and current state-of-the-art,and by identifying future research op-portunities to improve the applicability and operationalizability of CI component identification and prioritization methods.Theoretical and practical applications are reviewed for definitions,analysis and modelling approaches regarding the resilience of interdependent infrastructure systems.A detailed review of infrastructure criticality definitions,component criticality assessment and prioritization frameworks,from scientific,policy and other documents,is presented.A discussion on social justice and equity dimensions therein is included,which have the potential to greatly influence decisions and should always be incorporated in infrastructure planning and in-vestment discussions.The findings of this review are discussed in terms of applicability and operationalizability.Key recommendations for future research include:(i)developing quantification frameworks for CI component criticality based on formal definitions and multiple criteria,(ii)incorporating the entire resilience cycle of CI in component prioritization,(iii)accounting for the socio-technical nature of CI systems by integrating social di-mensions and their wider operating environment and(iv)developing comprehensive model validation,cali-bration and uncertainty analysis frameworks.
基金Supported by National Natural Science Foundation of China(Grant Nos.52422510,52373320,52175360,50725517)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(Grant No.2021QNRC001)+1 种基金the Key R&D Program of Hubei Province(Grant No.2024BAB080)Natural Science Foundation of Wuhan(Grant No.2024040801020257).
文摘In aerospace,nuclear power,and new energy vehicles industries,utilizing integrated metal components with extreme sizes and/or structures is crucial for achieving significant weight-saving,performance-improvement,and excellent reliability.These components,made from metal sheets,rings,or tubes,exhibit characteristics like ultra-thin,ultra-thick,ultra-large,ultra-long,ultra-high ribs,and large variable diameters.During plastic de-formation in metal forming processes,defects such as ruptures,wrinkles,excessive strain differences,and un-expected weak performance areas are likely to occur due to the intersection of multiple effects in different research disciplines,including materials science,processes,and mechanics of materials.Consequently,the smooth forming of integrated parts is difficult.It is the first time to review,summarize,and analyze the ad-vancement of forming methods for producing integrated parts with extreme sizes and structures.The general academic ideas to change the process conditions and sequences to optimize stress state and improve plastic deformation ability for forming the components with extreme sizes/structures are introduced.Practical ex-amples,discussed in detail in the paper,include the forming of(i)integrated ultra-thin and ultra-thick sheet components;(ii)integrated ultra-large size ring components with thin wall and high ribs;and(iii)integrated ultra-long tube components with large perimeter difference.Various plasticity technologies and process se-quences have been developed.The key processes and applications of the technologies are discussed in detail,which achieve successful plastic forming of integrated components.This paper provides state-of-the-art and perspectives for the rapidly advancing material forming fields of key metal components for the next generation of equipment.
文摘The goal of the present work is to demonstrate the potential of Artificial Neural Network(ANN)-driven Genetic Algorithm(GA)methods for energy efficiency and economic performance optimization of energy efficiency measures in a multi-family house building in Greece.The energy efficiency measures include different heating/cooling systems(such as low-temperature and high-temperature heat pumps,natural gas boilers,split units),building envelope components for floor,walls,roof and windows of variable heat transfer coefficients,the installation of solar thermal collectors and PVs.The calculations of the building loads and investment and operating and maintenance costs of the measures are based on the methodology defined in Directive 2010/31/EU,while economic assumptions are based on EN 15459-1 standard.Typically,multi-objective optimization of energy efficiency measures often requires the simulation of very large numbers of cases involving numerous possible combinations,resulting in intense computational load.The results of the study indicate that ANN-driven GA methods can be used as an alternative,valuable tool for reliably predicting the optimal measures which minimize primary energy consumption and life cycle cost of the building with greatly reduced computational requirements.Through GA methods,the computational time needed for obtaining the optimal solutions is reduced by 96.4%-96.8%.
文摘电子元器件种类繁多且没有一致的细粒度分类标准,为快速满足元器件在不同粒度下的分类需求,提出一种基于深度学习的YOLOR-ECA(YOLOv8 and ResNet50 with efficient channel attention)电子元器件检测算法。首先采用YOLOv8网络定位元器件位置,然后采用ResNet50网络对定位获取的元器件进行识别分类,通过元器件种类的增减满足不同细粒度的分类标准。为提升模型对尺寸小、特征相似元器件的细节特征提取能力,分类网络引入ECA注意力机制,并对残差结构的捷径连接部分进行改进;为避免神经元失活,采用GELU(Gaussian Error Linear Units)激活函数。实验结果表明,改进的YOLOR-ECA模型的检测准确率为96.6%,并且对于小尺寸元器件的识别精度最高可达100%,对于具有特征相似性元器件的误检率最低可降到0.01%,能实现电子元器件在不同细粒度分类标准下的高效检测。
基金Supported by The National Natural Science Foundation of China,No.30400576 and No.30672588
文摘AIM:To investigate the effect of severe acute pan- creatitis(SAP)on pharmacokinetics of Da-Cheng-Qi Decoction(DCQD)components in rats. METHODS:Rats were divided into SAP group and sham-operation group as a control group(n=6). Rhein,chrysophanol,rheochrysidin,magnolol,hesperidin and naringin in DCQD were quantified in rat serum by high performance liquid chromatography tandem mass spectrometry for studying their pharmacokinetics. RESULTS:Early absorption of each DCQD component was tended to degrade in SAP group after treatment with DCQD by gavage.The Cmax(chrysophanol,P= 0.0059;rheochrysidin,P=0.0288;magnolol,P= 0.0487;hesperidin,P=0.0277;naringin,P=0.0023) and AUC(rhein,P=0.0186;chrysophanol,P=0.0013; magnolol,P=0.001;hesperidin,P=0.0081;naringin, P=0.0272)of DCQD component were obviously lower in SAP group than in control group.The T1/2α of chrysophanol and rheochrysidin(P=0.0467 and 0.0005,respectively)and Tmax of chrysophanol and rheochrysidin(P=0.0101 and 0.0037,respectively) lasted longer in SAP group than in control group. CONCLUSION:SAP can significantly impact the ab-sorption of DCQD components in rats and their phar-macokinetic parameters.
基金Project supported by the National Natural Science Foundation of China(Grant No.61671142)
文摘Studying the topology of infrastructure communication networks(e.g., the Internet) has become a means to understand and develop complex systems. Therefore, investigating the evolution of Internet network topology might elucidate disciplines governing the dynamic process of complex systems. It may also contribute to a more intelligent communication network framework based on its autonomous behavior. In this paper, the Internet Autonomous Systems(ASes) topology from 1998 to 2013 was studied by deconstructing and analysing topological entities on three different scales(i.e., nodes,edges and 3 network components: single-edge component M1, binary component M2 and triangle component M3). The results indicate that: a) 95% of the Internet edges are internal edges(as opposed to external and boundary edges); b) the Internet network consists mainly of internal components, particularly M2 internal components; c) in most cases, a node initially connects with multiple nodes to form an M2 component to take part in the network; d) the Internet network evolves to lower entropy. Furthermore, we find that, as a complex system, the evolution of the Internet exhibits a behavioral series,which is similar to the biological phenomena concerned with the study on metabolism and replication. To the best of our knowledge, this is the first study of the evolution of the Internet network through analysis of dynamic features of its nodes,edges and components, and therefore our study represents an innovative approach to the subject.
基金the National Natural Science Foundation of China(No.31570343).
文摘Albiziae Flos(AF)has been experimentally proven to have an antidepressant effect.However,due to the complexity of botanical ingredients,the exact pharmacological mechanism of action of AF in depression has not been completely deciphered.This study used the network pharmacology method to construct a component-target-pathway network to explore the active components and potential mechanisms of action of AF.The methods included collection and screening of chemical components,prediction of depression-associated targets of the active components,gene enrichment,and network construction and analysis.Quercetin and 4 other active components were found to exert an tidepressant effects mainly via monoaminergic neurotransmitters and cAMP signaling and neuroactive ligand・wceptor interaction pathways.DRD2,HTR1 A,and SLC6A4 were identified as important targets of the studied bioactive components of AF.This network pharmacology analysis provides guidance for further study of the antidepressant mechanism of AF.
基金supported by the National Natural Science Foundation of China (30471009)
文摘Resynthesized rapeseeds obtained by crossing the diploid parents Brassica rapa and Brassica oleracea have significant potential in hybrid breeding because of their higher genetic basis compared with Brassica napus cultivars. In this study, an 8 × 8 complete diallel experiment using four B. napus cultivars （BN） and four resynthesized rapeseed lines （RS） as parents was designed to study heterosis and genetic inheritance for yield components. The results showed that heterosis for yield per plant, the number of pods per plant and number of seeds per pod were high, with means 32.77, 24.49 and 15.71%, respectively. Diallel analysis showed that both additive and dominant effects were significant for yield and yield components. All traits, except for 1 000-seed weight, were significant for bl mean squares and exhibited directional dominance. Dominant genes had positive effects on yield per plant, pods per plant and 1000-seed weight, and negative effects on seeds per pod （r=-0.86, -0.62, -0.41, and 0.47, respectively）. Narrow-sense heritability for yield per plant, pods per plant, and 1 000-seed weight and seeds per pod were 66, 31, 46 and 78% for the four traits, respectively. The Fl hybrids showed considerable yields compared to B. napus cultivars when B. napus cultivars and resynthesized rapeseeds were used as parents （NR hybrids）, with many more pods per plant and lower seeds per pod compared with the rapeseed cultivars, indicating that the resynthesized rapeseed may be applicable in current hybrid breeding programs.
基金Project(70671039) supported by the National Natural Science Foundation of China
文摘A combined model based on principal components analysis (PCA) and generalized regression neural network (GRNN) was adopted to forecast electricity price in day-ahead electricity market. PCA was applied to mine the main influence on day-ahead price, avoiding the strong correlation between the input factors that might influence electricity price, such as the load of the forecasting hour, other history loads and prices, weather and temperature; then GRNN was employed to forecast electricity price according to the main information extracted by PCA. To prove the efficiency of the combined model, a case from PJM (Pennsylvania-New Jersey-Maryland) day-ahead electricity market was evaluated. Compared to back-propagation (BP) neural network and standard GRNN, the combined method reduces the mean absolute percentage error about 3%.
基金supported by State Key Laboratory of Heavy Oil Processing,China University of Petroleum
文摘The use of waste crumb rubber powder as a modifier for modified asphalt can recycle waste rubber to ease pressure on the environment and improve the performance of asphalt. Diffusion of components of asphalt into waste rubber is of vital importance to improve the performance of rubber modified asphalt,while the related researches are scarce. Diffusion of components of asphalt into waste rubber at different temperatures has been investigated in this work. Rectangle rubber was immersed in asphalt at certain temperature for a period of time. And the mass increment of rubber was measured to determine the diffusion rate of components of asphalt into rubber. The experimental results indicated that the diffusion rate of components of asphalt into waste rubber increases along the temperature,but the diffusion rate of components of fractions oil which is distillated from catalytic cracking slurry is much higher than that of components of asphalt. Compared with asphalt,fractions oil enjoys lower viscosity and better permeability with higher content of saturates and aromatics. All the characteristics are contributed to the efficient diffusion of components of fractions into waste rubber.
基金This work was jointly spored by the grants from the Natural Science Foundation of Henan Province(0511030500)the National 863 Program of China(2004AA2111112)the N ational Natural Science Foundation of China(30490250).
文摘The genetic analysis of soybean isoflavone content and its components were carried out based on the NC Ⅱ matingdesign in eight soybean varieties. The results showed that the isoflavone contents and its components of soybean seedare quite differences among the tested materials, the contents of isoflavone and daidzein are controlled not only byadditive effects and but also by non-additive effects, while the content of genistin is dominated by non-additive effects,and genistein, glycitin and daidzin are mainly controlled by additive effects. There are significant differences in thecontents of isoflavone and its components among the combinations derived from different parents. Results also indicatedthat the tested traits are negatively heterosis except for the contens of daidzein and daidzin are positively heterosis basedon the data of the GCA and SCA in average heterosis values. In this research we have a suggestion that soybean varietywith high isoflavone should be used as one of the parents in the breeding program, and it is the best choice that thecombinations crossed between two high isoflavone varieties or a high variety and a low one.
基金supported by the 47th Postdoctoral Fund in China (No. 20100470521)the Independent Selection Project of China Academy of Chinese Medical Sciences (No. Z02154)by China National Scientific Fundation (No. 81001596)
文摘Objective:To explore the network control mechanism of the calcium signaling pathway in cerebral ischemic injury after intervention by the main components of Qingkailing(清开灵),i.e.Baicalin,Jasminoidin and their combination.Methods:Thirty mice were randomly divided into 5 groups,a baicalin group,a Jasminoidin group,a baicalin plus Jasminoidin group,a nimodipine group,and a model group(n=6).The global cerebral ischemia-reperfusion mouse model was established.The mice were administrated respectively by injection of baicalin,Jasminoidin,mixture of baicalin and Jasminoidin,and nimodipine into the caudal vein,with the model group given no any drug.Three hours after operation,the brain was removed and sectioned.After calculation of cerebral ischemic area by 2,3,5-triphenyltetrazolium staining,the percentage of infarct volume was calculated.The total RNA of the mouse brain tissue was extracted to obtain the whole genome expression profile,and the differentially expressed genes related to the calcium signaling pathway was analyzed with Bayesian network structures.Results:Compared with the model group,the ischemic area was significantly reduced in the baicalin group,the Jasminoidin group,the Baicalin plus Jasminoidin group(all P<0.05).The ischemic area in the baicalin plus Jasminoidin group was smaller than the other three groups(all P<0.01).In the gene regulatory network structures of calcium signaling pathway,the average length and equitability were the highest in the baicalin plus Jasminoidin group,followed by the nimodipine group.Conclusion:Compared with a single component,combination of Baicalin and Jasminoidin can more obviously intervene in the overall expression of calcium signaling pathway,and the mechanism is related with the aggregation characteristic of the gene expression network.
基金the National Magnetic Confinement Fusion Program of China(Grant 2013GB113005)the National Natural Science Foundation of China(Grants51577139 and 51407132)for funding in part
文摘Magneto-mechanical coupling vibration arises in the in-vessel components of Tokamak devices especially during the plasma disruption. Strong electromagnetic forces cause the structures to vibrate while the motion in turn changes the distribution of the electromagnetic field. To ensure the Tokamak devices operating in a designed state, numerical analysis on the coupling vibration is of great importance. This paper introduces two numerical methods for the magneto-mechanical coupling problems. The coupling term of velocity and magnetic flux density is manipulated in both Eulerian and Lagrangian description, which brings much simplification in numerical implementation. Corresponding numerical codes have been developed and applied to the dynamic simulation of a test module in J-TEXT and the vacuum vessel of HL-2M during plasma disruptions. The results reveal the evident influence of the magnetic stiffness and magnetic damping effects on the vibration behavior of the in-vessel structures. Finally, to deal with the halo current injection problem, a numerical scheme is described and validated which can simulate the distribution of the halo current without complicated manipulations.
基金Supported by The Medical Imageology Special Purpose Foundation of Cancer Hospital/Cancer Institute Fudan University, No.YX200802
文摘AIM: To investigate the metabolic profiles of xenograft pancreatic cancer before and after radiotherapy by high-resolution magic angle spinning proton magnetic resonance spectroscopy (HRMAS 1H NMR) combined with principal components analysis (PCA) and evaluate the radiotherapeutic effect. METHODS: The nude mouse xenograft model of human pancreatic cancer was established by injecting human pancreatic cancer cell SW1990 subcutaneously into the nude mice. When the tumors volume reached 800 mm3 , the mice received various radiation doses. Two weeks later, tumor tissue sections were prepared for running the NMR measurements. 1H NMR and PCA were used to determine the changes in the metabolic profiles of tumor tissues after radiotherapy. Metabolic profiles of normal pancreas, pancreatic tumor tissues, and radiationtreated pancreatic tumor tissues were compared. RESULTS: Compared with 1H NMR spectra of the normal nude mouse pancreas, the levels of choline, taurine, alanine, isoleucine, leucine, valine, lactate, and glutamic acid of the pancreatic cancer group were increased, whereas an opposite trend for phosphocholine, glycerophosphocholine, and betaine was observed. The ratio of phosphocholine to creatine, and glycerophosphocholine to creatine showed noticeable decrease in the pancreatic cancer group. After further evaluation of the tissue metabolic profile after treatment with three different radiation doses, no significant change in metabolites was observed in the 1H NMR spectra, while the inhibition of tumor growth was in proportion to the radiation doses. However, PCA results showed that the levels of choline and betaine were decreased with the increased radiation dose, and conversely, the level of acetic acid was dramatically increased. CONCLUSION: The combined methods were demonstrated to have the potential for allowing early diagnosis and assessment of pancreatic cancer response to radiotherapy.
基金supported by National Natural Science Foundation of China(NSFC)(Nos.51705171 and 51975228)Natural Science Foundation of Guangdong(No.2020A151501638)the Program of China Scholarship Council(No.201806160076)。
文摘Machining performance of thin-walled components made by aeronautical difficult-toprocess materials is a significant issue in the aviation manufacturing industry.Although wire electric discharge machining-low speed(WEDM-LS)is one of typical non-contact machining processes without macro cutting force,which does well in removing hardness and brittleness materials via pulsed discharge at high temperature,but few researchers have studied the thermal distortion behavior leading to a considerable geometric error in the WEDM-LS of thin-walled components.In this paper,a transverse magnetic field assisted method is applied for affecting the uniformity of discharge point distribution so as to reduce the distortion in WEDM-LS processing thin-wall component.First,the generation mechanism of this new distortion behavior and the impact mechanism of transverse magnetic field(TMF)on distortion are demonstrated by theoretical analysis.In order to further figure out the distortion behavior in the TMF-WEDM process,a new thermophysical model considering the discharge point distribution is established to simulate temperature field,residual stress field and distortion profiles.Then a large number of Taguchi experiments are carried out to investigate the influences of process parameters including pulse discharge energy(pulse on time,pulse off time,and current)and magnetic field strength on distortion in WEDM-LS.To comparatively analyze simulated and experimental results,the accuracy of established thermophysical model is verified within a relative error of 18.38%in distortion.Moreover,it can be revealed that transverse magnetic field contribute to significantly improve the longitudinal distribution uniformity with maximum increase of 12.32%at magnetic field strength:0.15 T,leading to significant reductions of 32.77%in distortion and 22.68%in recast layer.Eventually,we also presented the variation of residual stress and recast layer along thickness direction under different distortion behavior,which are in good agreement with that of distortion behavior.
基金supported by the National Basic Research Program (973) of China (No. 2004CB117306)the Hi-Tech Research and Development Program (863) of China (No. 2006AA10A102)
文摘Association analysis provides an opportunity to find genetic variants underlying complex traits. A principal components regression （PCR）-based approach was shown to outperform some competing approaches. However, a limitation of this method is that the principal components （PCs） selected from single nucleotide polyrnorphisms （SNPs） may be unrelated to the phenotype. In this article, we investigate the theoretical properties of such a method in more detail. We first derive the exact power function of the test based on PCR, and hence clarify the relationship between the test power and the degrees of freedom （DF）. Next, we extend the PCR test to a general weighted PCs test, which provides a unified framework for understanding the properties of some related statistics. We then compare the performance of these tests. We also introduce several data-driven adaptive alternatives to overcome difficulties in the PCR approach. Finally, we illustrate our results using simulations based on real genotype data. Simulation study shows the risk of using the unsupervised rule to determine the number of PCs, and demonstrates that there is no single uniformly powerful method for detecting genetic variants.
基金jointly funded by the National Key Research and Development Project of China(No.2016YFC0600509)the National Natural Science Foundation of China(Nos.41972312,41672329,41272365)the China Geological Survey(No.1212011220922)。
文摘The tin(Sn)-tungsten(W)polymetallic ore concentrated district in SE Yunnan is distributed at the junction region of the Yangtze Block,the Cathaysian Block and the Indosinian Block,where there are several giant deposits of tin,tungsten,copper,silver,lead,zinc and indium closely associated with a large scale Late Cretaceous magmatism.Bi-dimensional empirical mode decomposition(BEMD)is used to extract aeromagnetic anomalous components at the survey scale of 1:200000 from the original aeromagnetic data of SE Yunnan.Four intrinsic mode functions(IMFs)and a residues component are obtained,which may reflect the geological structures and geological bodies at different spatial scales from high frequency to low frequency.The results are shown as follows:(1)Two different types of Precambrian basement in the study area were recognized:one is the Yangtze Block basement characterized by a strong positive magnetic anomaly,the other is the Cathaysian Block basement with a weak negative magnetic anomaly.The former consists of high grade metamorphic rocks including metamorphosed basic igneous rocks,while the latter consists of low grade metamorphosed sedimentary rocks.(2)The aeromagnetic anomalies associated with Sn-W polymetallic mineralization and related to granites in the study area illustrate a pattern of a skarnized alteration-mineralization zone with a positive ring magnetic anomaly enclosing a granitic intrusion with negative magnetic anomaly;(3)The ring positive magnetic anomaly zones enclosing the negative magnetic anomaly are defined as the SnW polymetallic ore-searching targets in the study area.
