The green transformation of agntcultural production plays a crucial role in promoting the high-quality drwelopment of agriculure and achiering rural reritaliation.In order to create favornble cooditions for this to oc...The green transformation of agntcultural production plays a crucial role in promoting the high-quality drwelopment of agriculure and achiering rural reritaliation.In order to create favornble cooditions for this to occur,it is essential to esablsh efetive connections,transformation,and mutual support betmeen capital endowment,external eovironment,and farmers'green concepes.ddionally.tha-ntrarting心apriolurml prodntin falitates srice-oriented sale operations,while the deep intgration of"Internet+"and agrioulture with the advancement of green agricaltural technology provides an inexbustible impetus for it.However,China's current green transformation of agricultural production continues to encounter challenges such as the depletion of a high quality labor force,obstades to building trust in the promotian ol ted hnology.and an underdeveloped geen agricultural products market.To address these callnges,it is imperative to promote embedded agricultural technology which can catalyee the groen contracting of agricultural production.Furthermore advocating for the consumption of green agricultural products will also be beneficial in overcoming these callengts.展开更多
A time-series similarity measurement method based on wavelet and matrix transform was proposed,and its anti-noise ability,sensitivity and accuracy were discussed. The time-series sequences were compressed into wavelet...A time-series similarity measurement method based on wavelet and matrix transform was proposed,and its anti-noise ability,sensitivity and accuracy were discussed. The time-series sequences were compressed into wavelet subspace,and sample feature vector and orthogonal basics of sample time-series sequences were obtained by K-L transform. Then the inner product transform was carried out to project analyzed time-series sequence into orthogonal basics to gain analyzed feature vectors. The similarity was calculated between sample feature vector and analyzed feature vector by the Euclid distance. Taking fault wave of power electronic devices for example,the experimental results show that the proposed method has low dimension of feature vector,the anti-noise ability of proposed method is 30 times as large as that of plain wavelet method,the sensitivity of proposed method is 1/3 as large as that of plain wavelet method,and the accuracy of proposed method is higher than that of the wavelet singular value decomposition method. The proposed method can be applied in similarity matching and indexing for lager time series databases.展开更多
This paper focuses on synthesizing a mixed robust H_2/H_∞ linear parameter varying(LPV) controller for the longitudinal motion of an air-breathing hypersonic vehicle via a high order singular value decomposition(H...This paper focuses on synthesizing a mixed robust H_2/H_∞ linear parameter varying(LPV) controller for the longitudinal motion of an air-breathing hypersonic vehicle via a high order singular value decomposition(HOSVD) approach.The design of hypersonic flight control systems is highly challenging due to the enormous complexity of the vehicle dynamics and the presence of significant uncertainties.Motivated by recent results on both LPV control and tensor-product(TP) model transformation approach,the velocity and altitude tracking control problems for the air-breathing hypersonic vehicle is reduced to that of a state feedback stabilizing controller design for a polytopic LPV system with guaranteed performances.The controller implementation is converted into a convex optimization problem with parameterdependent linear matrix inequalities(LMIs) constraints,which is intuitively tractable using LMI control toolbox.Finally,numerical simulation results demonstrate the effectiveness of the proposed approach.展开更多
The advanced heat flux manipulating structures inspired by TO-based spatial mapping have aroused wide interests owing to huge potential in high-efficient thermal energy utilization.However,most researches are limited ...The advanced heat flux manipulating structures inspired by TO-based spatial mapping have aroused wide interests owing to huge potential in high-efficient thermal energy utilization.However,most researches are limited to the realization of single function in one specific structure and appropriate evaluation of the energy transfer process is relatively lacking.In this work,based on time-dependent two-dimensional heat conduction equation,a co-effect structure capable of accomplishing concentration and rotation functions simultaneously is established and validated by finite element simulations compared with the conventional single concentrator and singe rotator.In addition,from the perspective of thermodynamics,the transformed local entropy production rate and total entropy production are theoretically derived and applied to evaluate the quality of energy transfer processes.The proposed co-effect structure can help to explore other potential mass/flux manipulating devices and the evaluation method is valuable for the further manufacturing as well as optimization of these devices in engineering applications.展开更多
Many methods have been proposed to extract the most relevant areas of an image. This article explores the method of edge detection by the multiscale product (MP) of the wavelet transform. The wavelet used in this wo...Many methods have been proposed to extract the most relevant areas of an image. This article explores the method of edge detection by the multiscale product (MP) of the wavelet transform. The wavelet used in this work is the first derivative of a bidimensional Gaussian function. InitiaRy, we construct the wavelet, then we present the MP approach which is applied to binary and grey levels images. This method is compared with other methods without noise and in the presence of noise. The experiment results show fhht the MP method for edge detection outPerforms conventional methods even in noisy environments.展开更多
Altrenogest(ALT),drospirenone(DRO),and melengestrol acetate(MLA)are three highly potent synthetic progestins that can be released into agricultural soils,while their fate in soil minerals remains unclear.This study ex...Altrenogest(ALT),drospirenone(DRO),and melengestrol acetate(MLA)are three highly potent synthetic progestins that can be released into agricultural soils,while their fate in soil minerals remains unclear.This study explored the transformation of these progestins in MnO_(2),SiO_(2),and ferrihydrite suspensions and identified their transformation products(TPs)via high resolution mass spectrometry and density functional theory calculations.Transformations were only observed for DRO and MLA in SiO_(2) suspension and ALT in MnO_(2) suspension(half-lives=0.86 min–9.90 day).ALT transformation was facilitated at higher MnO_(2) loadings,while DRO and MLA transformations were inhibited at higher SiO_(2) loadings.These data indicated that hydrophobic partitioning interactionwas dominant at higher SiO_(2) loadings rather than specific interaction,which limited subsequent surface-catalyzed transformation.ALT transformation rate decreased with increasing pH because MnO_(2) reduction requires proton participation.In contrast,relatively high pH facilitated MLA and DRO transformation,indicating that base-catalyzed hydrolysis occurred in SiO_(2) suspension.The clustermap demonstrated the formation of abundant TPs.Lactone ring and acetoxy group hydrolysis was the major transformation pathway for DRO and MLA,with estimated yields of 57.7%and 173.2%at 6 day,respectively.ALT experienced C12 hydroxylation and formed the major TP 326g(yield of 15.4%at 8 hr).ALT also experienced allyl group oxidation and subsequent C5 hydroxylation,forming the major TP 344a(yield of 14.1%at 8 hr).This study demonstrates that TPs ofmetastable progestins are likely the main species in soils and that TP identification is a particular priority for risk assessment.展开更多
This study investigated the degradation of clofibric acid(CFA),bezafibrate(BZF),and sulfamethoxazole(SMX)in synthetic human urine using a novel mesoporous iron powderactivated persulfate system(mFe-PS system),and iden...This study investigated the degradation of clofibric acid(CFA),bezafibrate(BZF),and sulfamethoxazole(SMX)in synthetic human urine using a novel mesoporous iron powderactivated persulfate system(mFe-PS system),and identified the factors limiting their degradation in synthetic human urine.A kinetic model was established to expose the radical production in various reaction conditions,and experiments were conducted to verify the modeling results.In the phosphate-containing mFe-PS system,the 120 min removal efficiency of CFA decreased from 95.1%to 76.6%as the phosphate concentration increased from 0.32 to 6.45 mmol/L,but recovered to 90.5%when phosphate concentration increased to 16.10 mmol/L.Meanwhile,the increased concentration of phosphate from 0.32 to 16.10mmol/L reduced the BZF degradation efficacy from 91.5%to 79.0%,whereas SMX removal improved from 37.3%to 62.9%.The m Fe-PS system containing(bi)carbonate,from 4.20 to166.70 mmol/L,reduced CFA and BZF removal efficiencies from 100%to 76.8%and 80.4%,respectively,and SMX from 83.5%to 56.7%within a 120-min reaction time.In addition,alkaline conditions(pH≥8.0)inhibited CFA and BZF degradations,while nonacidic pH(pH≥7.0)remarkably inhibited SMX degradation.Results of the kinetic model indicated the formation of phosphate(H_(2)PO_(4)^(·)/HPO_(4)^(·-))and/or carbonate radicals(CO_(3)^(·-))could limit pharmaceutical removal.The transformation products(TPs)of the pharmaceuticals revealed more incompletely oxidized TPs occurred in the phosphate-and(bi)carbonate-containing m Fe-PS systems,and indicated that H_(2)PO_(4)^(·)/HPO_(4)^(·-)mainly degraded pharmaceuticals via a benzene ring-opening reaction while CO_(3)^(·-)preferentially oxidized pharmaceuticals via a hydroxylation reaction.展开更多
Pharmaceutical and personal care products(PPCPs)and corresponding transformation products have caused widespread concern due to their persistent emissions and potential toxicity.They have wide octanol-water partition ...Pharmaceutical and personal care products(PPCPs)and corresponding transformation products have caused widespread concern due to their persistent emissions and potential toxicity.They have wide octanol-water partition coefficients(K_(ow))and different ionization constants(pK_(a))resulting in a poor analysis accuracy and efficiency.A suitable analytical method is the first prerequisite for further research on their environmental behavior to prioritize the substances.This study reviewed a full-scale analytical protocol for environmental samples in the recent ten years:from sampling to instrumental methods.Passive sampling techniques were compared and recommended for long-term continuous and scientific observation.A quick and effective sample extraction and clean-up method are highly required.Chromatographic methods coupled to mass spectrometry for determining PPCPs with a wide range of logK_(ow)(-7.53 to 10.80)were summed up.High-resolution mass spectrometry was confirmed to be a promising strategy for screening unknown transformation products,which would provide a nanogram level of detection limits and more accurate mass resolution.Screening strategies and mass change principles were summarized in detail.The recovery rate was important in multiple contaminants analysis identification and factors affecting the recovery rate of PPCPs were also discussed in this review,including sample matrix,target compounds characteristics,extraction method and solid-phase adsorbent.This review provides useful information for the selection of appropriate analytical methods and future development directions.展开更多
Gibberellic acid(GA_(3))is widely used in agriculture and maybe transfer with groundwater flow,which is an endocrine disruptor,but few studies have focused on the transformation pathway and toxicity assessment of GA_(...Gibberellic acid(GA_(3))is widely used in agriculture and maybe transfer with groundwater flow,which is an endocrine disruptor,but few studies have focused on the transformation pathway and toxicity assessment of GA_(3)and its products.Here,GA_(3)and its transformation products in aqueous solution were identified and quantified by liquid chromatography mass spectrometry hybrid ion trap time-of-flight(LCMS-IT-TOF)and high-performance liquid chromatography(HPLC),respectively.The results showed that the half-life of GA_(3)transformation in ultrapure water was 16.1–24.6 days at p H=2.0–8.0,with the lowest half-life occurring at p H=8.0 and highest half-life occurring at p H=3.3.Isomerized gibberellic acid(Iso-GA_(3))and gibberellenic acid(GEA)were the main transformation products with a little hydroxy gibberellic acid(OH-GA_(3)).In North China groundwater,the mass balance of GA_(3)and its products was 76.2%,including Iso-GA_(3)(58%),GEA(7.9%),GA_(3)(7.3%)and OH-GA_(3)(3%)after reaching transformation equilibrium.Using Gaussian 09 for chemical computation,it was found that the transformation mechanism of GA_(3)was dependent upon the bond energy and the stereochemical feature of its molecular structure.GA_(3)always isomerized from theγ-lactone ring due to the lowest bond energy between the oxygen terminus of theγ-lactone ring and A ring.While GA_(3)and its transformation products all had developmental toxicity,the predicated LC 50(96 hr)and LD 50 of the main products of GA_(3)were much lower than those of GA_(3),indicating GA_(3)would be transformed into higher toxicity derivatives in water environments,posing a significant health risk to humans and the environment.展开更多
The transformation of free state organic micro-pollutants(MPs)has been widely studied;however,few studies have focused on mixed and bound states MPs,even though numerous ionizable organic MPs process a strong tendency...The transformation of free state organic micro-pollutants(MPs)has been widely studied;however,few studies have focused on mixed and bound states MPs,even though numerous ionizable organic MPs process a strong tendency to combine with dissolved organic matters in aquatic environments.This study systemically investigated the distribution and toxicity assessment of tetracycline(TET)transformation products in free,mixed and bound states during UV,UV/H2O2,UV/PS and CNTs/PS processes.A total of 33 major transformation products were identified by UPLC-Q-TOF-MSMS analysis,combining the double bond equivalence and aromaticity index calculations.The binding interaction would weaken the attack on the dimethylamino(-N(CH3)2)group and induce the direct destruction of rings A and B of TET through the analysis of 2D Kernel Density changes and density functional theory(DFT)calculations.Toxicity assessment and statistics revealed that the intermediate products with medium molecular weight(230m/z380)exhibited higher toxicity,which was closely related to the number of the rings in molecular structures(followed as 2»3>1z4).A predicted toxicity accumulation model(PTAM)was established to evaluate the overall toxicity changes during various oxidation processes.This finding provides new insight into the fate of bound MPs during various oxidation processes in the natural water matrix.展开更多
Pharmaceuticals and personal care products(PPCPs)have received increasing attention.However,their transformation products(TPs)and metabolites,sometimes even with environmental concentration and/or toxicity higher than...Pharmaceuticals and personal care products(PPCPs)have received increasing attention.However,their transformation products(TPs)and metabolites,sometimes even with environmental concentration and/or toxicity higher than their parent compounds,received attention far from enough.This study gives useful insight on the occurrence,fate and toxicity of PPCP TPs or metabolites in WWTPs,surface water and even drinking water,highlighting the necessity of studying the PPCP TPs formation,occurrence,toxicity and environment risk,and further evaluating the environmental risk caused by PPCPs comprehensively.展开更多
Duloxetine(DUL), an antidepressant drug, has been detected in surface water and wastewater effluents, however, there is little information on the formation of its transformation products(TPs). In this work, hydrolysis...Duloxetine(DUL), an antidepressant drug, has been detected in surface water and wastewater effluents, however, there is little information on the formation of its transformation products(TPs). In this work, hydrolysis, photodegradation(UV irradiation) and chlorination experiments were performed on spiked distillated water, under controlled experimental conditions to simulate abiotic processes that can occur in the environment and wastewater treatment plants(WWTPs). Eleven TPs, nine from reaction with UV light and two from chlorine contact, were formed and detected by ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry, and nine of them had their chemical structures elucidated upon analyses of their fragmentation patterns in MS/MS spectra. The formation and degradation of the TPs were observed. The parent compound was completely degraded after30 min in photodegradation and after 24 hr in chlorination. Almost all TPs were completely degraded in the experiments. The ecotoxicity and mutagenicity of the TPs were predicted based on several in silico models and it was found that a few of these products presented more ecotoxicity than DUL itself and six TPs showed positive mutagenicity. Finally, wastewater samples were analyzed and DUL and one TP, possibly formed by chlorination process, were detected in the effluent, which showed that WWTP not only did not remove DUL, but also formed a TP.展开更多
This paper proposes a graphical-based methodology to evaluate the performance of a manufacturing system in terms of network model.We focus on a manufacturing system which consists of multiple distinct production lines...This paper proposes a graphical-based methodology to evaluate the performance of a manufacturing system in terms of network model.We focus on a manufacturing system which consists of multiple distinct production lines.A transformation technique is developed to build the manufacturing system as a manufacturing network.In such a manufacturing network,the capacity of each machine is multistate due to failure,partial failure,or maintenance.Thus,this manufacturing network is also regarded as a multistate network.We evaluate the probability that the manufacturing network can meet a given demand,where the probability is referred to as the system reliability.A simple algorithm integrating decomposition technique is proposed to generate the minimal capacity vectors that machines should provide to eventually satisfy demand.The system reliability is derived in terms of such capacity vectors afterwards.A practical application in the context of IC card manufacturing system is utilized to demonstrate the performance evaluation procedure.展开更多
The purpose of this study was to examine whether transforming growth factor-β (TGFβ acts as an autocrine cytokine in cultured mesangial cells. Measangial cell conditioned media (CM) were prepared and tested for thei...The purpose of this study was to examine whether transforming growth factor-β (TGFβ acts as an autocrine cytokine in cultured mesangial cells. Measangial cell conditioned media (CM) were prepared and tested for their effect on mesangial cell proliferation. CM showed a concentration dependent inhibition on mesangial cell proliferation and the activity was enhanced by treating conditioned media with acid. Gel filtration analysis showed peak inhibitory activity to reside in fractions with an estimated molecular weight range of 16-30 KD. The activity was partially blocked by anti-TGFβ antibody, but not nonimmune control IgG. The presence of TGFβ was confirmed using the mink lung epithelial cell assay. Furthermore, the addition of anti-TGFβ antibody directly into culture media significantly enhanced mesangial cell proliferation. These results demonstrate that measangial cell produce both active and latent forms of TGFβ, which functions as an autocrine growth inhibitor for mesangial cells.展开更多
Extant research mostly focuses on the impact of big data on product development(PD)process and performance,and yet there is a lack of theoretical exploration of the transformation path,realization mechanism and transf...Extant research mostly focuses on the impact of big data on product development(PD)process and performance,and yet there is a lack of theoretical exploration of the transformation path,realization mechanism and transformation paradigm while moving from experience-based PD(EBPD)to data-driven PD(DDPD).This paper,from the integrated perspective of adaptive change and organizational routines,and based on an in-depth case study of HSTYLE,proposes a two-stage transformation model for moving from EBPD to DDPD,dissects the adaptive change mechanism of organizational routines for DDPD,puts forward a theoretical model for the transformation paradigm for DDPD,and provides an innovative interpretation of the connotation of data-driven.This paper constructs a theory for DDPD transformation that comprises three aspects:transformation path,realization mechanism and transformation paradigm.Conclusions of this paper have policy implications for enterprises in their practice on data-driven product innovation in the digital economy era.展开更多
This article analyzed the influence of increasing wages on cropping patterns from theoretical and empirical perspectives.The results showed that the increasing labor cost provided a significant incentive to adjust the...This article analyzed the influence of increasing wages on cropping patterns from theoretical and empirical perspectives.The results showed that the increasing labor cost provided a significant incentive to adjust the grain cropping pattern,which increased the production of the three major cereal grains but reduced the production of other grain crops.Increasing wages had a significant negative impact on cash crops.More laborintensive cash crops experienced a larger negative impact in the context of increasing wages.The increase in labor costs also had a negative impact on the proportion of vegetables produced,which was more evident in northern China.A further mechanism test indicated that factor substitution was a significant reason for cropping pattern changes;this illustrated the substitution of labor by machinery not only between grain crops and cash crops but also among different cash crops.展开更多
Available online Iodinated X-ray contrast media (ICMs) are clinical drugs used to enhance the imaging effect.Triiodobenzene ring structures of ICMs lead to its extremely high chemical stability,biological inertness,wh...Available online Iodinated X-ray contrast media (ICMs) are clinical drugs used to enhance the imaging effect.Triiodobenzene ring structures of ICMs lead to its extremely high chemical stability,biological inertness,which makes it difficult to be completely removed by traditional water treatment processes.Hence,considerable concentration of ICMs can be frequently detected in aquatic environment.Relying on the strong oxidation capacity of HO·or SO_(4)^(·-),various advanced oxidation processes (AOPs) have demonstrated substantial removal efficiency for ICMs.It is evident that ICMs can be decomposed mainly through(1) deiodination,(2) dehydration,(3) decarboxylation,(4) H-abstraction,(5) hydroxyl addition,(6) hydroxyl substitution,(7) oxidation of alcohol groups,(8) cleavage of amide bond,and (9) amino oxidation.However,during the ICMs removal process,the C-I bonds of ICMs molecules are broken,giving rise to the formation of cytotoxic iodination disinfection by-products (I-DBPs) that are potentially more harmful to the ecosystem and human health than their parent compounds.To better understand the technology gaps,this review elaborates the major AOPs which are effective for ICMs removal and emphasizes on the main degradation routes of ICMs in different oxidation system.Some prevailing concerns and challenges are discussed for optimizing the ICMs treatment process.展开更多
The widely used carbamazepine(CBZ)is one of the most persistent pharmaceuticals and suffers insufficient removal efficiency by conventional wastewater treatment.A synthesized Co-based perovskite(LaCoO3)was used to act...The widely used carbamazepine(CBZ)is one of the most persistent pharmaceuticals and suffers insufficient removal efficiency by conventional wastewater treatment.A synthesized Co-based perovskite(LaCoO3)was used to activate peroxymonosulfate(PMS)in order to degrade CBZ.Results showed that LaCoO3 exhibited an excellent performance in PMS activation and CBZ degradation at neutral pH,with low cobalt leaching.The results of FT-IR and XPS verified the high structurally and chemically stability of LaCoO3 in PMS activation.Electron spin resonance(ESR)analysis suggested the generation of radical species,such as sulfate radicals(SO4·-)and hydroxyl radicals(·OH).Radical quenching experiments further revealed the responsibility of SO4·-as the dominant oxidant for CBZ oxidation.Ten products were detected via the oxidation of CBZ,with the olefinic double bond attacked by SO4·-as the initial step.Hydroxylation,hydrolysis,cyclization and dehydration were involved along the transformation of CBZ.The toxicity of CBZ solution was significantly reduced after treating by PMS/LaCoO3.展开更多
During the aging process,ferrihydrite was transformed into mineral mixtures composed of different proportions of ferrihydrite,goethite,lepidocrocite and hematite.Such a transformation may affect the fixed ability of a...During the aging process,ferrihydrite was transformed into mineral mixtures composed of different proportions of ferrihydrite,goethite,lepidocrocite and hematite.Such a transformation may affect the fixed ability of arsenic.In this study,the stability of Fe-As composites formed with As(Ⅴ)and the minerals aged for 0,1,4,10 and 30 days of ferrihydrite were systematically examined,and the effects of molar of ratios Fe/As were also clarified using kinetic methods combined with multiple spectroscopic techniques.The results indicated that As(Ⅴ)was rapidly adsorbed on minerals during the initial polymerization process,which delayed both the ferrihydrite conversion and the hematite formation.When the Fe/As molar ratio was 1.875 and 5.66,the As(Ⅴ)adsorbed by ferrihydrite began to release after 6 hr and 12 hr,respectively.The corresponding release amounts of As(Ⅴ)were 0.55 g/L and 0.07 g/L,and the adsorption rates were 92.43%and 97.50%at 60 days,respectively.However,the As(Ⅴ)adsorbed by the transformation products aged for 30 days of ferrihydrite began to release after adsorbed 30 days.The corresponding release amounts of As(Ⅴ)were 0.25 g/L and 0.03 g/L,and the adsorption rates were 84.23%and 92.18%after adsorbed 60 days,for the Fe/As=1.875 and 5.66,respectively.Overall,the combination of As(Ⅴ)with ferrihydrite and aged products transformed from a thermodynamically metastable phase to a dynamically stable state within a certain duration.Moreover,the aging process of ferrihydrite reduced the sorption ability of arsenate by iron(hydr)oxide but enhanced the stability of the Fe-As composites.展开更多
基金This paper is supported by"Research onthe Mechanism,Effect,and Policy Optimization of Environmental Regulation and Green Transformation of Farmer Production"(No.19CJL019)a youth program of the National Social Fund of China+3 种基金"Study on the Mechanism of the Paid Exit of Farmland Contracting Rights on the Urbanization of Agriculturally Transferred Population"(No.71973137)a general project of National Natural Science Foundation of Chinaand"Research on the Policy of Cooperating to Protect Forestry and Grasslands in the Yangtze River Economic Belt"(No.500102-1721)a research on major forestry issues of the State Forestry and Grassland Administration.
文摘The green transformation of agntcultural production plays a crucial role in promoting the high-quality drwelopment of agriculure and achiering rural reritaliation.In order to create favornble cooditions for this to occur,it is essential to esablsh efetive connections,transformation,and mutual support betmeen capital endowment,external eovironment,and farmers'green concepes.ddionally.tha-ntrarting心apriolurml prodntin falitates srice-oriented sale operations,while the deep intgration of"Internet+"and agrioulture with the advancement of green agricaltural technology provides an inexbustible impetus for it.However,China's current green transformation of agricultural production continues to encounter challenges such as the depletion of a high quality labor force,obstades to building trust in the promotian ol ted hnology.and an underdeveloped geen agricultural products market.To address these callnges,it is imperative to promote embedded agricultural technology which can catalyee the groen contracting of agricultural production.Furthermore advocating for the consumption of green agricultural products will also be beneficial in overcoming these callengts.
基金Projects(60634020, 60904077, 60874069) supported by the National Natural Science Foundation of ChinaProject(JC200903180555A) supported by the Foundation Project of Shenzhen City Science and Technology Plan of China
文摘A time-series similarity measurement method based on wavelet and matrix transform was proposed,and its anti-noise ability,sensitivity and accuracy were discussed. The time-series sequences were compressed into wavelet subspace,and sample feature vector and orthogonal basics of sample time-series sequences were obtained by K-L transform. Then the inner product transform was carried out to project analyzed time-series sequence into orthogonal basics to gain analyzed feature vectors. The similarity was calculated between sample feature vector and analyzed feature vector by the Euclid distance. Taking fault wave of power electronic devices for example,the experimental results show that the proposed method has low dimension of feature vector,the anti-noise ability of proposed method is 30 times as large as that of plain wavelet method,the sensitivity of proposed method is 1/3 as large as that of plain wavelet method,and the accuracy of proposed method is higher than that of the wavelet singular value decomposition method. The proposed method can be applied in similarity matching and indexing for lager time series databases.
基金supported by the National Natural Science Foundation of China(6120300761304239+1 种基金61503392)the Natural Science Foundation of Shaanxi Province(2015JQ6213)
文摘This paper focuses on synthesizing a mixed robust H_2/H_∞ linear parameter varying(LPV) controller for the longitudinal motion of an air-breathing hypersonic vehicle via a high order singular value decomposition(HOSVD) approach.The design of hypersonic flight control systems is highly challenging due to the enormous complexity of the vehicle dynamics and the presence of significant uncertainties.Motivated by recent results on both LPV control and tensor-product(TP) model transformation approach,the velocity and altitude tracking control problems for the air-breathing hypersonic vehicle is reduced to that of a state feedback stabilizing controller design for a polytopic LPV system with guaranteed performances.The controller implementation is converted into a convex optimization problem with parameterdependent linear matrix inequalities(LMIs) constraints,which is intuitively tractable using LMI control toolbox.Finally,numerical simulation results demonstrate the effectiveness of the proposed approach.
基金the National Natural Science Foundation of China(Grant Nos.51776050 and 51536001).
文摘The advanced heat flux manipulating structures inspired by TO-based spatial mapping have aroused wide interests owing to huge potential in high-efficient thermal energy utilization.However,most researches are limited to the realization of single function in one specific structure and appropriate evaluation of the energy transfer process is relatively lacking.In this work,based on time-dependent two-dimensional heat conduction equation,a co-effect structure capable of accomplishing concentration and rotation functions simultaneously is established and validated by finite element simulations compared with the conventional single concentrator and singe rotator.In addition,from the perspective of thermodynamics,the transformed local entropy production rate and total entropy production are theoretically derived and applied to evaluate the quality of energy transfer processes.The proposed co-effect structure can help to explore other potential mass/flux manipulating devices and the evaluation method is valuable for the further manufacturing as well as optimization of these devices in engineering applications.
基金supported by the University of Tunis El Manar and National Engineering School of Tunis
文摘Many methods have been proposed to extract the most relevant areas of an image. This article explores the method of edge detection by the multiscale product (MP) of the wavelet transform. The wavelet used in this work is the first derivative of a bidimensional Gaussian function. InitiaRy, we construct the wavelet, then we present the MP approach which is applied to binary and grey levels images. This method is compared with other methods without noise and in the presence of noise. The experiment results show fhht the MP method for edge detection outPerforms conventional methods even in noisy environments.
基金supported by the National Natural Science Foundation of China(Nos.42177367,41877063,and U1901601)the National Key Research and Development Programof China(No.2019YFC1804400)the Central Government Fund Supporting Non-profit Scientific Institutes for Basic Research and Development(No.PM-zx703-202112-332).
文摘Altrenogest(ALT),drospirenone(DRO),and melengestrol acetate(MLA)are three highly potent synthetic progestins that can be released into agricultural soils,while their fate in soil minerals remains unclear.This study explored the transformation of these progestins in MnO_(2),SiO_(2),and ferrihydrite suspensions and identified their transformation products(TPs)via high resolution mass spectrometry and density functional theory calculations.Transformations were only observed for DRO and MLA in SiO_(2) suspension and ALT in MnO_(2) suspension(half-lives=0.86 min–9.90 day).ALT transformation was facilitated at higher MnO_(2) loadings,while DRO and MLA transformations were inhibited at higher SiO_(2) loadings.These data indicated that hydrophobic partitioning interactionwas dominant at higher SiO_(2) loadings rather than specific interaction,which limited subsequent surface-catalyzed transformation.ALT transformation rate decreased with increasing pH because MnO_(2) reduction requires proton participation.In contrast,relatively high pH facilitated MLA and DRO transformation,indicating that base-catalyzed hydrolysis occurred in SiO_(2) suspension.The clustermap demonstrated the formation of abundant TPs.Lactone ring and acetoxy group hydrolysis was the major transformation pathway for DRO and MLA,with estimated yields of 57.7%and 173.2%at 6 day,respectively.ALT experienced C12 hydroxylation and formed the major TP 326g(yield of 15.4%at 8 hr).ALT also experienced allyl group oxidation and subsequent C5 hydroxylation,forming the major TP 344a(yield of 14.1%at 8 hr).This study demonstrates that TPs ofmetastable progestins are likely the main species in soils and that TP identification is a particular priority for risk assessment.
基金supported by the Hong Kong Innovation and Technology Commission (No.ITC-CNERC14EG03)the Research Grants Council of the Hong Kong SAR (No.T21-604/19R)。
文摘This study investigated the degradation of clofibric acid(CFA),bezafibrate(BZF),and sulfamethoxazole(SMX)in synthetic human urine using a novel mesoporous iron powderactivated persulfate system(mFe-PS system),and identified the factors limiting their degradation in synthetic human urine.A kinetic model was established to expose the radical production in various reaction conditions,and experiments were conducted to verify the modeling results.In the phosphate-containing mFe-PS system,the 120 min removal efficiency of CFA decreased from 95.1%to 76.6%as the phosphate concentration increased from 0.32 to 6.45 mmol/L,but recovered to 90.5%when phosphate concentration increased to 16.10 mmol/L.Meanwhile,the increased concentration of phosphate from 0.32 to 16.10mmol/L reduced the BZF degradation efficacy from 91.5%to 79.0%,whereas SMX removal improved from 37.3%to 62.9%.The m Fe-PS system containing(bi)carbonate,from 4.20 to166.70 mmol/L,reduced CFA and BZF removal efficiencies from 100%to 76.8%and 80.4%,respectively,and SMX from 83.5%to 56.7%within a 120-min reaction time.In addition,alkaline conditions(pH≥8.0)inhibited CFA and BZF degradations,while nonacidic pH(pH≥7.0)remarkably inhibited SMX degradation.Results of the kinetic model indicated the formation of phosphate(H_(2)PO_(4)^(·)/HPO_(4)^(·-))and/or carbonate radicals(CO_(3)^(·-))could limit pharmaceutical removal.The transformation products(TPs)of the pharmaceuticals revealed more incompletely oxidized TPs occurred in the phosphate-and(bi)carbonate-containing m Fe-PS systems,and indicated that H_(2)PO_(4)^(·)/HPO_(4)^(·-)mainly degraded pharmaceuticals via a benzene ring-opening reaction while CO_(3)^(·-)preferentially oxidized pharmaceuticals via a hydroxylation reaction.
基金supported by the National Natural Science Foundation of China(No.41977142)the Major Science and Technology Program for Water Pollution Control and Treatment(No.2018ZX07111003)+1 种基金the Key Technologies Research and Development Program(No.2019YFC1806104)the Fundamental Research Funds for the Central Universities(No.JD2006)。
文摘Pharmaceutical and personal care products(PPCPs)and corresponding transformation products have caused widespread concern due to their persistent emissions and potential toxicity.They have wide octanol-water partition coefficients(K_(ow))and different ionization constants(pK_(a))resulting in a poor analysis accuracy and efficiency.A suitable analytical method is the first prerequisite for further research on their environmental behavior to prioritize the substances.This study reviewed a full-scale analytical protocol for environmental samples in the recent ten years:from sampling to instrumental methods.Passive sampling techniques were compared and recommended for long-term continuous and scientific observation.A quick and effective sample extraction and clean-up method are highly required.Chromatographic methods coupled to mass spectrometry for determining PPCPs with a wide range of logK_(ow)(-7.53 to 10.80)were summed up.High-resolution mass spectrometry was confirmed to be a promising strategy for screening unknown transformation products,which would provide a nanogram level of detection limits and more accurate mass resolution.Screening strategies and mass change principles were summarized in detail.The recovery rate was important in multiple contaminants analysis identification and factors affecting the recovery rate of PPCPs were also discussed in this review,including sample matrix,target compounds characteristics,extraction method and solid-phase adsorbent.This review provides useful information for the selection of appropriate analytical methods and future development directions.
基金supported by the National Natural Science Foundation of China(No.41772245)the National Key Research and Development Program of China(No.2019YFC1805400)the Fundamental Research Funds for the Central Universities(No.2020ZDPY0201)。
文摘Gibberellic acid(GA_(3))is widely used in agriculture and maybe transfer with groundwater flow,which is an endocrine disruptor,but few studies have focused on the transformation pathway and toxicity assessment of GA_(3)and its products.Here,GA_(3)and its transformation products in aqueous solution were identified and quantified by liquid chromatography mass spectrometry hybrid ion trap time-of-flight(LCMS-IT-TOF)and high-performance liquid chromatography(HPLC),respectively.The results showed that the half-life of GA_(3)transformation in ultrapure water was 16.1–24.6 days at p H=2.0–8.0,with the lowest half-life occurring at p H=8.0 and highest half-life occurring at p H=3.3.Isomerized gibberellic acid(Iso-GA_(3))and gibberellenic acid(GEA)were the main transformation products with a little hydroxy gibberellic acid(OH-GA_(3)).In North China groundwater,the mass balance of GA_(3)and its products was 76.2%,including Iso-GA_(3)(58%),GEA(7.9%),GA_(3)(7.3%)and OH-GA_(3)(3%)after reaching transformation equilibrium.Using Gaussian 09 for chemical computation,it was found that the transformation mechanism of GA_(3)was dependent upon the bond energy and the stereochemical feature of its molecular structure.GA_(3)always isomerized from theγ-lactone ring due to the lowest bond energy between the oxygen terminus of theγ-lactone ring and A ring.While GA_(3)and its transformation products all had developmental toxicity,the predicated LC 50(96 hr)and LD 50 of the main products of GA_(3)were much lower than those of GA_(3),indicating GA_(3)would be transformed into higher toxicity derivatives in water environments,posing a significant health risk to humans and the environment.
基金The authors would like to thank the National Natural Science Foundation of China(NO.51878422)Science and Technology Projects of Sichuan Province(2018 HH0104)+1 种基金Science and Technology Bureau of Chengdu(2017-GH02-00010-342 HZ)Innovation Spark Project in Sichuan University(Grant No.2082604401254)for the financial support.
文摘The transformation of free state organic micro-pollutants(MPs)has been widely studied;however,few studies have focused on mixed and bound states MPs,even though numerous ionizable organic MPs process a strong tendency to combine with dissolved organic matters in aquatic environments.This study systemically investigated the distribution and toxicity assessment of tetracycline(TET)transformation products in free,mixed and bound states during UV,UV/H2O2,UV/PS and CNTs/PS processes.A total of 33 major transformation products were identified by UPLC-Q-TOF-MSMS analysis,combining the double bond equivalence and aromaticity index calculations.The binding interaction would weaken the attack on the dimethylamino(-N(CH3)2)group and induce the direct destruction of rings A and B of TET through the analysis of 2D Kernel Density changes and density functional theory(DFT)calculations.Toxicity assessment and statistics revealed that the intermediate products with medium molecular weight(230m/z380)exhibited higher toxicity,which was closely related to the number of the rings in molecular structures(followed as 2»3>1z4).A predicted toxicity accumulation model(PTAM)was established to evaluate the overall toxicity changes during various oxidation processes.This finding provides new insight into the fate of bound MPs during various oxidation processes in the natural water matrix.
基金This work was financially supported by the National Natural Science Foundation of China(21577075)Tsinghua University Initiative Scientific Research Program(20131089193)Program for Changjiang Scholars and Innovative Research Team in University(IRT1261).
文摘Pharmaceuticals and personal care products(PPCPs)have received increasing attention.However,their transformation products(TPs)and metabolites,sometimes even with environmental concentration and/or toxicity higher than their parent compounds,received attention far from enough.This study gives useful insight on the occurrence,fate and toxicity of PPCP TPs or metabolites in WWTPs,surface water and even drinking water,highlighting the necessity of studying the PPCP TPs formation,occurrence,toxicity and environment risk,and further evaluating the environmental risk caused by PPCPs comprehensively.
基金supported by Brazilian Federal Agency Coordenacao de Aperfeicoamento de Pessoal de Nível Superior(CAPES)for PhD grants(No.99999.000845/2014-00)Fundacao para a Ciência e a Tecnologia(FCT)Portugal(Projects UID/MULTI/00612/2013,PEst-OE/QUI/UI0612/2013 and LISBOA-01-0145-FEDER-022125)
文摘Duloxetine(DUL), an antidepressant drug, has been detected in surface water and wastewater effluents, however, there is little information on the formation of its transformation products(TPs). In this work, hydrolysis, photodegradation(UV irradiation) and chlorination experiments were performed on spiked distillated water, under controlled experimental conditions to simulate abiotic processes that can occur in the environment and wastewater treatment plants(WWTPs). Eleven TPs, nine from reaction with UV light and two from chlorine contact, were formed and detected by ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry, and nine of them had their chemical structures elucidated upon analyses of their fragmentation patterns in MS/MS spectra. The formation and degradation of the TPs were observed. The parent compound was completely degraded after30 min in photodegradation and after 24 hr in chlorination. Almost all TPs were completely degraded in the experiments. The ecotoxicity and mutagenicity of the TPs were predicted based on several in silico models and it was found that a few of these products presented more ecotoxicity than DUL itself and six TPs showed positive mutagenicity. Finally, wastewater samples were analyzed and DUL and one TP, possibly formed by chlorination process, were detected in the effluent, which showed that WWTP not only did not remove DUL, but also formed a TP.
基金supported in part by the National Science Council of Taiwan under Grant No.NSC 99-2221-E-011-066-MY3
文摘This paper proposes a graphical-based methodology to evaluate the performance of a manufacturing system in terms of network model.We focus on a manufacturing system which consists of multiple distinct production lines.A transformation technique is developed to build the manufacturing system as a manufacturing network.In such a manufacturing network,the capacity of each machine is multistate due to failure,partial failure,or maintenance.Thus,this manufacturing network is also regarded as a multistate network.We evaluate the probability that the manufacturing network can meet a given demand,where the probability is referred to as the system reliability.A simple algorithm integrating decomposition technique is proposed to generate the minimal capacity vectors that machines should provide to eventually satisfy demand.The system reliability is derived in terms of such capacity vectors afterwards.A practical application in the context of IC card manufacturing system is utilized to demonstrate the performance evaluation procedure.
文摘The purpose of this study was to examine whether transforming growth factor-β (TGFβ acts as an autocrine cytokine in cultured mesangial cells. Measangial cell conditioned media (CM) were prepared and tested for their effect on mesangial cell proliferation. CM showed a concentration dependent inhibition on mesangial cell proliferation and the activity was enhanced by treating conditioned media with acid. Gel filtration analysis showed peak inhibitory activity to reside in fractions with an estimated molecular weight range of 16-30 KD. The activity was partially blocked by anti-TGFβ antibody, but not nonimmune control IgG. The presence of TGFβ was confirmed using the mink lung epithelial cell assay. Furthermore, the addition of anti-TGFβ antibody directly into culture media significantly enhanced mesangial cell proliferation. These results demonstrate that measangial cell produce both active and latent forms of TGFβ, which functions as an autocrine growth inhibitor for mesangial cells.
基金This paper is the best paper of China Enterprise Management Cases and Qualitative Research Forum 2019.This paper is supported by the National Natural Science Foundation of China(No.71832014,71771223,71902193)the China Postdoctoral Science Foundation(No.2019M653258).
文摘Extant research mostly focuses on the impact of big data on product development(PD)process and performance,and yet there is a lack of theoretical exploration of the transformation path,realization mechanism and transformation paradigm while moving from experience-based PD(EBPD)to data-driven PD(DDPD).This paper,from the integrated perspective of adaptive change and organizational routines,and based on an in-depth case study of HSTYLE,proposes a two-stage transformation model for moving from EBPD to DDPD,dissects the adaptive change mechanism of organizational routines for DDPD,puts forward a theoretical model for the transformation paradigm for DDPD,and provides an innovative interpretation of the connotation of data-driven.This paper constructs a theory for DDPD transformation that comprises three aspects:transformation path,realization mechanism and transformation paradigm.Conclusions of this paper have policy implications for enterprises in their practice on data-driven product innovation in the digital economy era.
基金the Major Program of National Fund of Philosophy and Social Science of China(No.21&ZD092)the National Natural Science Foundation of China(Nos.72161147001 and 72103134)the Research Program for Humanities and Social Science of the Chinese Ministry of Education(No.21YJC790139).
文摘This article analyzed the influence of increasing wages on cropping patterns from theoretical and empirical perspectives.The results showed that the increasing labor cost provided a significant incentive to adjust the grain cropping pattern,which increased the production of the three major cereal grains but reduced the production of other grain crops.Increasing wages had a significant negative impact on cash crops.More laborintensive cash crops experienced a larger negative impact in the context of increasing wages.The increase in labor costs also had a negative impact on the proportion of vegetables produced,which was more evident in northern China.A further mechanism test indicated that factor substitution was a significant reason for cropping pattern changes;this illustrated the substitution of labor by machinery not only between grain crops and cash crops but also among different cash crops.
基金supported by the Science&Technology Innovation Action Plan of Shanghai under the Belt and Road Initiative (No.19230742800)。
文摘Available online Iodinated X-ray contrast media (ICMs) are clinical drugs used to enhance the imaging effect.Triiodobenzene ring structures of ICMs lead to its extremely high chemical stability,biological inertness,which makes it difficult to be completely removed by traditional water treatment processes.Hence,considerable concentration of ICMs can be frequently detected in aquatic environment.Relying on the strong oxidation capacity of HO·or SO_(4)^(·-),various advanced oxidation processes (AOPs) have demonstrated substantial removal efficiency for ICMs.It is evident that ICMs can be decomposed mainly through(1) deiodination,(2) dehydration,(3) decarboxylation,(4) H-abstraction,(5) hydroxyl addition,(6) hydroxyl substitution,(7) oxidation of alcohol groups,(8) cleavage of amide bond,and (9) amino oxidation.However,during the ICMs removal process,the C-I bonds of ICMs molecules are broken,giving rise to the formation of cytotoxic iodination disinfection by-products (I-DBPs) that are potentially more harmful to the ecosystem and human health than their parent compounds.To better understand the technology gaps,this review elaborates the major AOPs which are effective for ICMs removal and emphasizes on the main degradation routes of ICMs in different oxidation system.Some prevailing concerns and challenges are discussed for optimizing the ICMs treatment process.
基金supported by the National Natural Science Foundation of China(Nos.51878431,51878465)the Fundamental Research Funds for the Central Universities(Nos.22120180504)
文摘The widely used carbamazepine(CBZ)is one of the most persistent pharmaceuticals and suffers insufficient removal efficiency by conventional wastewater treatment.A synthesized Co-based perovskite(LaCoO3)was used to activate peroxymonosulfate(PMS)in order to degrade CBZ.Results showed that LaCoO3 exhibited an excellent performance in PMS activation and CBZ degradation at neutral pH,with low cobalt leaching.The results of FT-IR and XPS verified the high structurally and chemically stability of LaCoO3 in PMS activation.Electron spin resonance(ESR)analysis suggested the generation of radical species,such as sulfate radicals(SO4·-)and hydroxyl radicals(·OH).Radical quenching experiments further revealed the responsibility of SO4·-as the dominant oxidant for CBZ oxidation.Ten products were detected via the oxidation of CBZ,with the olefinic double bond attacked by SO4·-as the initial step.Hydroxylation,hydrolysis,cyclization and dehydration were involved along the transformation of CBZ.The toxicity of CBZ solution was significantly reduced after treating by PMS/LaCoO3.
基金the Agricultural Science and Tech-nology Innovation Program of the Chinese Academy of Agricul-tural Sciences(No.CAAS-ASTIP-2016-IEDA)。
文摘During the aging process,ferrihydrite was transformed into mineral mixtures composed of different proportions of ferrihydrite,goethite,lepidocrocite and hematite.Such a transformation may affect the fixed ability of arsenic.In this study,the stability of Fe-As composites formed with As(Ⅴ)and the minerals aged for 0,1,4,10 and 30 days of ferrihydrite were systematically examined,and the effects of molar of ratios Fe/As were also clarified using kinetic methods combined with multiple spectroscopic techniques.The results indicated that As(Ⅴ)was rapidly adsorbed on minerals during the initial polymerization process,which delayed both the ferrihydrite conversion and the hematite formation.When the Fe/As molar ratio was 1.875 and 5.66,the As(Ⅴ)adsorbed by ferrihydrite began to release after 6 hr and 12 hr,respectively.The corresponding release amounts of As(Ⅴ)were 0.55 g/L and 0.07 g/L,and the adsorption rates were 92.43%and 97.50%at 60 days,respectively.However,the As(Ⅴ)adsorbed by the transformation products aged for 30 days of ferrihydrite began to release after adsorbed 30 days.The corresponding release amounts of As(Ⅴ)were 0.25 g/L and 0.03 g/L,and the adsorption rates were 84.23%and 92.18%after adsorbed 60 days,for the Fe/As=1.875 and 5.66,respectively.Overall,the combination of As(Ⅴ)with ferrihydrite and aged products transformed from a thermodynamically metastable phase to a dynamically stable state within a certain duration.Moreover,the aging process of ferrihydrite reduced the sorption ability of arsenate by iron(hydr)oxide but enhanced the stability of the Fe-As composites.