Discharge plasma parameter measurement is a key focus in low-temperature plasma research.Traditional diagnostics often require costly equipment,whereas electro-acoustic signals provide a rich,non-invasive,and less com...Discharge plasma parameter measurement is a key focus in low-temperature plasma research.Traditional diagnostics often require costly equipment,whereas electro-acoustic signals provide a rich,non-invasive,and less complex source of discharge information.This study harnesses machine learning to decode these signals.It establishes links between electro-acoustic signals and gas discharge parameters,such as power and distance,thus streamlining the prediction process.By building a spark discharge platform to collect electro-acoustic signals and implementing a series of acoustic signal processing techniques,the Mel-Frequency Cepstral Coefficients(MFCCs)of the acoustic signals are extracted to construct the predictors.Three machine learning models(Linear Regression,k-Nearest Neighbors,and Random Forest)are introduced and applied to the predictors to achieve real-time rapid diagnostic measurement of typical spark discharge power and discharge distance.All models display impressive performance in prediction precision and fitting abilities.Among them,the k-Nearest Neighbors model shows the best performance on discharge power prediction with the lowest mean square error(MSE=0.00571)and the highest R-squared value(R^(2)=0.93877).The experimental results show that the relationship between the electro-acoustic signal and the gas discharge power and distance can be effectively constructed based on the machine learning algorithm,which provides a new idea and basis for the online monitoring and real-time diagnosis of plasma parameters.展开更多
Streptococcus thermophilus is one of the most prevalent species in stool samples of westernized populations due to continuous exposure to fermented dairy products.However,few studies have explored the effect on host p...Streptococcus thermophilus is one of the most prevalent species in stool samples of westernized populations due to continuous exposure to fermented dairy products.However,few studies have explored the effect on host physiology by multiple S.thermophilus strains and considered the inter-strain differences in regulating host.In the present study,we investigated how four S.thermophilus strains influenced the gut microbiota,mucin changes,and host metabolism after 28 days of intervention in conventional mice.The results indicated that the consumption of S.thermophilus affected the host with strain specificity.Among four S.thermophilus strains,DYNDL13-4 and DQHXNQ38M61,especially DQHXNQ38M61,had more effect on host physiology by modulating gut microbiota and host metabolism than LMD9 and 4M6.Ingestion of strains DYNDL13-4 and DQHXNQ38M61 resulted in more remarkable changes in amino acid metabolism and lipid metabolism than that of strains LMD9 and 4M6,which may be related to the elevation of intestinal Bifidobacterium by DYNDL13-4 and DQHXNQ38M61.The enriched Coriobacteriaceae UCG-002,Rikenellaceae RC9 gut group,and Lactobacillus only in the DQHXNQ38M61 group,had a close relationship with the prominent effect of DQHXNQ38M61 on regulating amino acid and lipid metabolism.In addition,DQHXNQ38M61 had a strong influence on degrading colonic mucin fucose by decreasedα-fucosidase activity in feces,and improving mucin sulfation by upregulated Gal3ST2 expression.Comparative genomic analysis revealed that the four S.thermophilus strains belonged to different branches in the phylogenetic tree,and DYNDL13-4 and DQHXNQ38M61 had more genes involved in carbohydrate metabolism,amino acid metabolism,membrane transport,and signal transduction,which may confer the capacity of nutrient utilization and gastrointestinal adaptation of the strains and be associated with their strong regulation in host.Our study provides valuable information for understanding the regulation of host metabolism after consuming different S.thermophilus strains and could facilitate potential personalized applications of S.thermophilus based on strain varieties.展开更多
The boundary value problems of the third-order ordinary differential equation have many practical application backgrounds and their some special cases have been studied by many authors. However, few scholars have stud...The boundary value problems of the third-order ordinary differential equation have many practical application backgrounds and their some special cases have been studied by many authors. However, few scholars have studied the boundary value problems of the complete third-order differential equations u′′′(t) = f (t,u(t),u′(t),u′′(t)). In this paper, we discuss the existence and uniqueness of solutions and positive solutions of the fully third-order ordinary differential equation on [0,1] with the boundary condition u(0) = u′(1) = u′′(1) = 0. Under some inequality conditions on nonlinearity f some new existence and uniqueness results of solutions and positive solutions are obtained.展开更多
Electric arc furnace dust(EAFD)is a hazardous waste but can also be a potential secondary resource for valuable metals,such as Zn and Fe.Given the increased awareness of carbon emission reduction,energy conservation,a...Electric arc furnace dust(EAFD)is a hazardous waste but can also be a potential secondary resource for valuable metals,such as Zn and Fe.Given the increased awareness of carbon emission reduction,energy conservation,and environmental protection,hydrometallurgical technologies for the detoxification and resource use of EAFD have been developing rapidly.This work summarizes the generation mechanisms,compositions,and characteristics of EAFD and presents a critical review of various hydrometallurgical treatment methods for EAFD,e.g.,acid leaching,alkaline leaching,salt leaching,and pretreatment–enhanced leaching methods.Simultaneously,the phase transformation mechanisms of zinc-containing components in acid and alkali solutions and pretreatment processes are expounded.Finally,two novel combined methods,i.e.,oxygen pressure sulfuric acid leaching combined with composite catalyst preparation,and synergistic roasting of EAFD and municipal solid waste incineration fly ash combined with alkaline leaching,are proposed,which can provide future development directions to completely recycling EAFD by recovering valuable metals and using zinc residue.展开更多
Photocatalytic processes are efficient methods to solve water contamination problems,especially considering dyeing wastewater disposal.However,high-efficiency photocatalysts are usually very expensive and have the ris...Photocatalytic processes are efficient methods to solve water contamination problems,especially considering dyeing wastewater disposal.However,high-efficiency photocatalysts are usually very expensive and have the risk of heavy metal pollution.Recently,an iron oxides@hydrothermal carbonation carbon(HTCC)heterogeneous catalyst was prepared by our group through co-hydrothermal treatment of carbohydrates and zinc extraction tailings of converter dust.Herein,the catalytic performance of the iron oxides@HTCC was verified by a nonbiodegradable dye,methylene blue(MB),and the catalytic mechanism was deduced from theoretical simulations and spectroscopic measurements.The iron oxides@HTCC showed an excellent synergy between photocatalysis and Fenton-like reactions.Under visible-light illumination,the iron oxides@HTCC could be excited to generate electrons and holes,reacting with H_(2)O_(2)to produce·OH radicals to oxidize and decompose organic pollutants.The removal efficiency of methylene blue over iron oxides@HTCC at 140 min was 2.86 times that of HTCC.The enhanced catalytic performance was attributed to the advantages of iron oxides modification:(1)promoting the excitation induced by photons;(2)improving the charge transfer.Furthermore,the iron oxides@HTCC showed high catalytic activity in a wide pH value range of 2.3-10.4,and the MB removal efficiency remained higher than 95% after the iron oxides@HTCC was recycled 4 times.The magnetically recyclable iron oxides@HTCC may provide a solution for the treatment of wastewater from the textile industry.展开更多
The Helanshan tectonic belt(HTB) is a major tectonic divide between the Alxa and Ordos blocks in the North China Craton. The geochronology and petrogenesis of the mafic dykes in the northern HTB are keys to understand...The Helanshan tectonic belt(HTB) is a major tectonic divide between the Alxa and Ordos blocks in the North China Craton. The geochronology and petrogenesis of the mafic dykes in the northern HTB are keys to understanding the tectonic evolution of this belt. The mafic dykes, intruded into the Neoarchean-Paleoproterozoic metamorphic basement, are mainly composed of diabase with a mineral assemblage of plagioclase(45%-60%), pyroxene(25%-35%), minor quartz and Fe-Ti oxides. The LA-ICPMS U-Pb analysis of zircon grains from representative dykes yield a weighted mean age of 206 ± 1.9 Ma, which represents the crystallization age of the dyke. The diabases show high contents of Fe_2 O_3~T(11.88-17.55 wt.%), low contents of SiO_2(45.65-50.95 wt.%) and MgO(3.31-5.50 wt.%) with low Mg#(=100×MgO/(MgO + FeO) atomic ration) of 33-44. They are characterized by enrichment of light rare earth elements(LREEs) and large ion lithophile elements(LILEs)(e.g., Rb, Ba and Pb), and slight depletion of high field strength elements(HFSEs). These features suggest that the magma has undergone extensive fractionation of olivine and pyroxene but only minor crustal contamination during its evolution. Their high Sm contents and La/Sm ratios, and low Sm/Yb ratios indicate that magma from which the dykes formed was derived from low degree(about 5%) partial melting of an enriched garnet + spinel lherzolite mantle source. Together with regional geology, these geochemical and geochronological data suggest that the mafic dykes in the HTB were formed in an intracontinental extensional setting during the late Triassic.展开更多
Optimized nitrogen(N)management can increase N-use efficiency in intercropping systems.Legume-nonlegume intercropping systems can reduce N input by exploiting biological N fixation by legumes.Measurement of N utilizat...Optimized nitrogen(N)management can increase N-use efficiency in intercropping systems.Legume-nonlegume intercropping systems can reduce N input by exploiting biological N fixation by legumes.Measurement of N utilization can help in dissecting the mechanisms underlying N uptake and utilization in legume-nonlegume intercropping systems.An experiment was performed with three planting patterns:monoculture maize(MM),monoculture soybean(SS),and maize-soybean relay intercropping(IMS),and three N application levels:zero N(NN),reduced N(RN),and conventional N(CN)to investigate crop N uptake and utilization characteristics.N recovery efficiency and 15N recovery rate of crops were higher under RN than under CN,and those under RN were higher under intercropping than under the corresponding monocultures.Compared with MM,IMS showed a lower soil N-dependent rate(SNDR)in 2012.However,the SNDR of MM rapidly declined from 86.8%in 2012 to 49.4%in 2014,whereas that of IMS declined slowly from 75.4%in 2012 to 69.4%in 2014.The interspecific N competition rate(NCRms)was higher under RN than under CN,and increased yearly.Soybean nodule dry weight and nitrogenase activities were respectively 34.2%and 12.5%higher under intercropping than in monoculture at the beginning seed stage.The amount(Ndfa)and ratio(%Ndfa)of soybean N2 fixation were significantly greater under IS than under SS.In conclusion,N fertilizer was more efficiently used under RN than under CN;in particular,the relay intercropping system promoted N fertilizer utilization in comparison with the corresponding monocultures.An intercropping system helps to maintain soil fertility because interspecific N competition promotes biological N fixation by soybean by reducing N input.Thus,a maize-soybean relay intercropping system with reduced N application is sustainable and environmentally friendly.展开更多
It is well known that the gut microbiota plays an extremely important role in modulating host physiological functions such as immunity and metabolic homeostasis.In recent years,accumulated evidence has revealed that t...It is well known that the gut microbiota plays an extremely important role in modulating host physiological functions such as immunity and metabolic homeostasis.In recent years,accumulated evidence has revealed that the gut microbiota can regulate the functions of the central nervous system(CNS)through the gut-brain axis,which provides a novel insight into the interactions between the gut and brain.This review focuses on the molecular mechanism of the crosstalk between the gut microbiota and the brain via the gut-brain axis,and on the onset and development of neurological disorders triggered by gut microbiota dysbiosis.These topics are followed by a critical analysis of potential intervention strategies targeting gut microbiota dysbiosis,including the use of probiotics,prebiotics,synbiotics,and diets.While research on the microbiota-gut-brain axis is still in its relative infancy,clarifying the molecular mechanism that underlies how the gut microbiota regulates neurological functions not only holds the promise of revealing potentially novel pathogeneses of neurological disorders,but also may lead to the development of potential diagnosis biomarkers and intervention strategies targeting microbiota dysbiosis for neurological disorders.展开更多
Adverse weather has a considerable impact on the behavior of drivers,which puts vehicles and drivers in hazardous situations that can easily cause traffic accidents.This research examines how drivers'perceived ris...Adverse weather has a considerable impact on the behavior of drivers,which puts vehicles and drivers in hazardous situations that can easily cause traffic accidents.This research examines how drivers'perceived risk changes during car following under different adverse weather conditions by using driving simulation experiment.An expressway road scenario was built in a driving simulator.Eleven types of weather conditions,including clear sky,four levels of fog,four levels of rain and two levels of snow,were designed.Furthermore,to simulate the carfollowing behavior,three car-following situations were designed according to the motion of the lead car.Seven car-following indicators were extracted based on risk homeostasis theory.Then,the entropy weight method was used to integrate the selected indicators into an index to represent the drivers'perceived risk.Multiple linear regression was applied to measure the influence of adverse weather conditions on perceived risk,and the coefficients were considered as indicators.The results demonstrate that both the weather conditions and road type have significant effects on car-following behavior.Drivers'perceived risk tends to increase with the worsening weather conditions.Under conditions of extremely poor visibility,such as heavy dense fog,the measured drivers'perceived risk is low due to the difficulties in vehicle operation and limited visibility.展开更多
The Chinese Altai in northwestern Xinjiang has numerous outcrops of granitoids which provide critical information on accretionary orogenic processes and crustal growth of the Central Asian Orogenic Belt.Zircon U-Pb ag...The Chinese Altai in northwestern Xinjiang has numerous outcrops of granitoids which provide critical information on accretionary orogenic processes and crustal growth of the Central Asian Orogenic Belt.Zircon U-Pb ages, Hf-isotopic compositions and whole-rock geochemistry of monzogranite and granodiorites in the Qinghe County are employed to elucidate Paleozoic tectonics of the Chinese Altai. Granodiorites have crystallization ages of 424.6 ± 3.1 Ma(MSWD = 0.23) and 404.0 ± 3.4 Ma(MSWD = 0.18);monzogranite was emplaced in the early Permian with a crystallization age of 293.7 ± 4.6 Ma(MSWD = 1.06). Both granodiorites and monzogranite are I-type granites with A/CNK ratios of 0.92 -0.97 and 1.03 -1.06, respectively. They also show similar geochemical features of high HREE and Y contents, low Sr contents and Sr/Y ratios, as well as enrichment of Cs, Rb, Th and U, and depletion of Nb, Ta, P and Ti.These geochemical features indicate that the monzogranite and granodiorites were formed in an arc setting related to subduction. The gneissic monzogranites display high SiO_2 and K_2 O contents, and belong to the high-K calc-alkaline series. In the chondrite normalized REE distribution pattern, the monzogranite samples exhibit enrichment of LREE with strong negative Eu anomalies(σE u =0.44 -0.53), zircon εHf(t) values from +7.24 to +12.63 and two-stage Hf model ages of 463 -740 Ma. This suggests that the monzogranite was generated from the mixing of pelitic and mantle material. The granodiorite samples are calc-alkaline granites with lower contents of Si O_2 and Na_2 O + K_2 O, higher contents of TiO_2, Fe_2O_3~t, MgO and CaO compared to the monzogranite samples. They also show enrichment of LREE and moderate negative Eu anomalies(σE u= 0.54 =0.81), as well as slightly higher differentiation of LREE than that of HREE. The425 Ma granodiorite has zircon εHf(t) values from -0.51 to +1.98 and two-stage Hf model ages of 1133 -1240 Ma, whereas the 404 Ma granodiorite displays those of +2.52 to +7.50 and 816 -1071 Ma.Geochemistry and zircon Hf isotopic compositions indicate that granodiorites were formed by partial melting of juvenile lower crust. Together with regional geology and previous data, the geochemical and geochronological data of the monzogranite and granodiorites from this study suggest long-lived subduction and accretion along the Altai Orogen during ca. 425 -294 Ma.展开更多
Circulating fluidized bed fly ash(CFBFA)is a solid waste product from circulating fluidized bed(CFB)boilers in power plants,and the storage of CFBFA is increasingly become an environmental problem.Previous scholars ha...Circulating fluidized bed fly ash(CFBFA)is a solid waste product from circulating fluidized bed(CFB)boilers in power plants,and the storage of CFBFA is increasingly become an environmental problem.Previous scholars have made contributions to improve the resource utilization of CFBFA.Especially,ecological cement is prepared by CFBFA,which is more conducive to its large-scale utilization.In recent years,a lot of effort has been paid to improve the properties of ecological cement containing CFBFA.In this work,the physicochemical properties of CFBFA are introduced,and recent research progress on the mechanical,expansion,and rheological properties of CFBFA based ecological cement(CEC)is extensively reviewed.The problem of over-expansion of f-CaO is summarized,which limits the scale application of CFBFA in ecological cement.Hence,the challenge for f-CaO in CFBFA to compensate for cement volume shrinkage is proposed,which is beneficial to the utilization of CFBFA in ecological cement,and the reduction of CO_(2) emissions from the cement industry.In addition,the environmental performance,durability,and economy of CEC should be valued in future research,especially the environmental performance,because the CFBFA contains heavy metals,such as Cr,As,which may pollute groundwater.展开更多
To overcome the current difficulties of high-precision machining and the high manufacturing and maintenance costs of spherical seals for deep-water drilling ball joints,a new spherical seal technique is proposed in th...To overcome the current difficulties of high-precision machining and the high manufacturing and maintenance costs of spherical seals for deep-water drilling ball joints,a new spherical seal technique is proposed in this paper.The spherical seal is mainly composed of silicone rubber and polytetrafluoroethylene(PTFE).Rational structural design makes the seal independent from the ball and other components,making it easy to replace if leakage occurs at its surface.PTFE can elastically deform over a certain deformation range,which guarantees that two sealing surfaces fit tightly together.O-Ring and PTFE elasticity makes up for any lack of accuracy during spherical machining and decreases the machining precision requirements for spherical surfaces.Using a finite element technique and nonlinear theory,the performance of the spherical seal under the influence of various factors is determined.The results show that the spherical seal designed in this paper exhibits excellent sealing performance under lowtemperature and high-pressure conditions.The spherical seal,a combination of an O-ring and PTFE,has the advantages of cheap manufacturing and maintenance costs and excellent sealing performance.展开更多
Global water security is a severe issue that threatens human health and well-being. Finding sustainable alternative water resources has become a matter of great urgency. For coastal urban areas, desalinated seawater c...Global water security is a severe issue that threatens human health and well-being. Finding sustainable alternative water resources has become a matter of great urgency. For coastal urban areas, desalinated seawater could serve as a freshwater supply. However, since 20%-30% of the water supply is used for flushing waste from the city, seawater with simple treatment could also partly replace the use of freshwater. In this work, the freshwater saving potential and environmental impacts of the urban water system （water-wastewater closed loop） adopting seawater desalination, seawater for toilet flushing （SWTF）, or reclaimed water for toilet flushing （RWTF） are compared with those of a conventional freshwater system, through a life-cycle assessment and sensitivity analysis. The potential applications of these processes are also assessed. The results support the environmental sustainability of the SWTF approach, but its potential application depends on the coastal distance and effective population density of a city. Developed coastal cities with an effective population density exceeding 3000 persons.km-2 and located less than 30 km from the seashore （for the main pipe supplying seawater to the city） would benefit from applying SWTF, regardless of other impact parameters. By further applying the sulfate reduction, autotrophic denitrification, and nitrification integrated （SANI） process for wastewater treatment, the maximum distance from the seashore can be extended to 60 km. Considering that most modern urbanized cities fulfill these criteria, the next generation of water supply systems could consist of a freshwater supply coupled with a seawater supply for sustainable urban development.展开更多
The researches on the heat generation and dissipa-tion of the permanent magnet synchronous machines(PMSMs)are integrated problems involving multidisciplinary studies of electromagnetism,thermomechanics,and computation...The researches on the heat generation and dissipa-tion of the permanent magnet synchronous machines(PMSMs)are integrated problems involving multidisciplinary studies of electromagnetism,thermomechanics,and computational fluid dynamics.The governing equations of the multi-physical prob-lems are coupled and hard to be solved and illustrated.The high accuracy mathematical model in the algebraically integral con-servative forms of the coupled fields is established and computed in this paper.And the equation coupling with the fluid flow and the temperature variation is modified to improve the positive definiteness and the symmetry of the global stiffness matrix.The computational burden is thus reduced by the model modification.A 20kW 4500rpm permanent magnet synchronous machine(PMSM)is taken as the prototype,and the calculation results are validated by experimental ones.展开更多
Magmatic zircon in high-grade metamorphic rocks is often characterized by complex textures as revealed by cathodoluminenscence （CL） that result from multiple episodes of recrystallization, over- growth, Pb-loss and ...Magmatic zircon in high-grade metamorphic rocks is often characterized by complex textures as revealed by cathodoluminenscence （CL） that result from multiple episodes of recrystallization, over- growth, Pb-loss and modifications through fluid-induced disturbances of the crystal structure and the original U-Th-Pb isotopic systematics. Many of these features can be recognized in 2-dimensional CL images, and isotopic analysis of such domains using a high resolution ion-microprobe with only shallow penetration of the zircon surface may be able to reconstruct much of the magmatic and complex post- magmatic history of such grains. In particular it is generally possible to find original magmatic domains yielding concordant ages. In contrast, destructive techniques such as LA-ICP-MS consume a large volume, leave a deep crater in the target grain, and often sample heterogeneous domains that are not visible and thus often yield discordant results which are difficult to interpret. We provide examples of complex magmatic zircon from a southern Indian granulite terrane where SHRIMP lI and LA-ICP-MS analyses are compared. The SHRIMP data are shown to be more precise and reliable, and we caution against the use of LA-ICP-MS in deciphering the chronology of complex zircons from high-grade terranes.展开更多
Traditional watermark embedding schemes inevitably modify the data in a host audio signal and lead to the degradation of the host signal.In this paper,a novel audio zero-watermarking algorithm based on discrete wavele...Traditional watermark embedding schemes inevitably modify the data in a host audio signal and lead to the degradation of the host signal.In this paper,a novel audio zero-watermarking algorithm based on discrete wavelet transform(DWT),discrete cosine transform(DCT),and singular value decomposition(SVD) is presented.The watermark is registered by performing SVD on the coefficients generated through DWT and DCT to avoid data modification and host signal degradation.Simulation results show that the proposed zero-watermarking algorithm is strongly robust to common signal processing methods such as requantization,MP3 compression,resampling,addition of white Gaussian noise,and low-pass filtering.展开更多
Essential characteristics for watermark registration and detection without data modification can be used in anaudio zero-watermarking scheme.In this paper,a novel audio zero-watermarking scheme based on discrete wavel...Essential characteristics for watermark registration and detection without data modification can be used in anaudio zero-watermarking scheme.In this paper,a novel audio zero-watermarking scheme based on discrete wavelet transform(DWT) and discrete cosine transform(DCT) is presented.Thewatermark is registered by comparing the mean absolute values of the adjacent frame coefficients after DWT and DCT.Simulation results show that the proposed scheme is stronglyrobusttocommon attacks such as AWGN,downsampling,low-pass filtering,requantization,and MP3 compression.A performance analysis of the proposed scheme shows that all bit error rates after attacks are zero.展开更多
基金partially supported by National Natural Science Foundation of China(No.52377155)the State Key Laboratory of Reliability and Intelligence of Electrical Equipment(No.EERI-KF2021001)Hebei University of Technology。
文摘Discharge plasma parameter measurement is a key focus in low-temperature plasma research.Traditional diagnostics often require costly equipment,whereas electro-acoustic signals provide a rich,non-invasive,and less complex source of discharge information.This study harnesses machine learning to decode these signals.It establishes links between electro-acoustic signals and gas discharge parameters,such as power and distance,thus streamlining the prediction process.By building a spark discharge platform to collect electro-acoustic signals and implementing a series of acoustic signal processing techniques,the Mel-Frequency Cepstral Coefficients(MFCCs)of the acoustic signals are extracted to construct the predictors.Three machine learning models(Linear Regression,k-Nearest Neighbors,and Random Forest)are introduced and applied to the predictors to achieve real-time rapid diagnostic measurement of typical spark discharge power and discharge distance.All models display impressive performance in prediction precision and fitting abilities.Among them,the k-Nearest Neighbors model shows the best performance on discharge power prediction with the lowest mean square error(MSE=0.00571)and the highest R-squared value(R^(2)=0.93877).The experimental results show that the relationship between the electro-acoustic signal and the gas discharge power and distance can be effectively constructed based on the machine learning algorithm,which provides a new idea and basis for the online monitoring and real-time diagnosis of plasma parameters.
基金supported by the National Natural Science Foundation of China(31871829,31820103010,and 32021005)the Collaborative Innovation Centre of Food Safety and Quality Control in Jiangsu Province(Jiangsu,China).
文摘Streptococcus thermophilus is one of the most prevalent species in stool samples of westernized populations due to continuous exposure to fermented dairy products.However,few studies have explored the effect on host physiology by multiple S.thermophilus strains and considered the inter-strain differences in regulating host.In the present study,we investigated how four S.thermophilus strains influenced the gut microbiota,mucin changes,and host metabolism after 28 days of intervention in conventional mice.The results indicated that the consumption of S.thermophilus affected the host with strain specificity.Among four S.thermophilus strains,DYNDL13-4 and DQHXNQ38M61,especially DQHXNQ38M61,had more effect on host physiology by modulating gut microbiota and host metabolism than LMD9 and 4M6.Ingestion of strains DYNDL13-4 and DQHXNQ38M61 resulted in more remarkable changes in amino acid metabolism and lipid metabolism than that of strains LMD9 and 4M6,which may be related to the elevation of intestinal Bifidobacterium by DYNDL13-4 and DQHXNQ38M61.The enriched Coriobacteriaceae UCG-002,Rikenellaceae RC9 gut group,and Lactobacillus only in the DQHXNQ38M61 group,had a close relationship with the prominent effect of DQHXNQ38M61 on regulating amino acid and lipid metabolism.In addition,DQHXNQ38M61 had a strong influence on degrading colonic mucin fucose by decreasedα-fucosidase activity in feces,and improving mucin sulfation by upregulated Gal3ST2 expression.Comparative genomic analysis revealed that the four S.thermophilus strains belonged to different branches in the phylogenetic tree,and DYNDL13-4 and DQHXNQ38M61 had more genes involved in carbohydrate metabolism,amino acid metabolism,membrane transport,and signal transduction,which may confer the capacity of nutrient utilization and gastrointestinal adaptation of the strains and be associated with their strong regulation in host.Our study provides valuable information for understanding the regulation of host metabolism after consuming different S.thermophilus strains and could facilitate potential personalized applications of S.thermophilus based on strain varieties.
文摘The boundary value problems of the third-order ordinary differential equation have many practical application backgrounds and their some special cases have been studied by many authors. However, few scholars have studied the boundary value problems of the complete third-order differential equations u′′′(t) = f (t,u(t),u′(t),u′′(t)). In this paper, we discuss the existence and uniqueness of solutions and positive solutions of the fully third-order ordinary differential equation on [0,1] with the boundary condition u(0) = u′(1) = u′′(1) = 0. Under some inequality conditions on nonlinearity f some new existence and uniqueness results of solutions and positive solutions are obtained.
基金financially supported by the National Natural Science Foundation of China(No.52074035)the Fundamental Research Funds for the Central Universities(No.00007720)the National Key Research and Development Program of China(No.2020YFC1910000)。
文摘Electric arc furnace dust(EAFD)is a hazardous waste but can also be a potential secondary resource for valuable metals,such as Zn and Fe.Given the increased awareness of carbon emission reduction,energy conservation,and environmental protection,hydrometallurgical technologies for the detoxification and resource use of EAFD have been developing rapidly.This work summarizes the generation mechanisms,compositions,and characteristics of EAFD and presents a critical review of various hydrometallurgical treatment methods for EAFD,e.g.,acid leaching,alkaline leaching,salt leaching,and pretreatment–enhanced leaching methods.Simultaneously,the phase transformation mechanisms of zinc-containing components in acid and alkali solutions and pretreatment processes are expounded.Finally,two novel combined methods,i.e.,oxygen pressure sulfuric acid leaching combined with composite catalyst preparation,and synergistic roasting of EAFD and municipal solid waste incineration fly ash combined with alkaline leaching,are proposed,which can provide future development directions to completely recycling EAFD by recovering valuable metals and using zinc residue.
基金financially supported by the National Natural Science Foundation of China(No.52074035)the Fundamental Research Funds for the Central Universities,China(No.00007720)the National Key Research and Development Program of China(No.2020YFC1910000)。
文摘Photocatalytic processes are efficient methods to solve water contamination problems,especially considering dyeing wastewater disposal.However,high-efficiency photocatalysts are usually very expensive and have the risk of heavy metal pollution.Recently,an iron oxides@hydrothermal carbonation carbon(HTCC)heterogeneous catalyst was prepared by our group through co-hydrothermal treatment of carbohydrates and zinc extraction tailings of converter dust.Herein,the catalytic performance of the iron oxides@HTCC was verified by a nonbiodegradable dye,methylene blue(MB),and the catalytic mechanism was deduced from theoretical simulations and spectroscopic measurements.The iron oxides@HTCC showed an excellent synergy between photocatalysis and Fenton-like reactions.Under visible-light illumination,the iron oxides@HTCC could be excited to generate electrons and holes,reacting with H_(2)O_(2)to produce·OH radicals to oxidize and decompose organic pollutants.The removal efficiency of methylene blue over iron oxides@HTCC at 140 min was 2.86 times that of HTCC.The enhanced catalytic performance was attributed to the advantages of iron oxides modification:(1)promoting the excitation induced by photons;(2)improving the charge transfer.Furthermore,the iron oxides@HTCC showed high catalytic activity in a wide pH value range of 2.3-10.4,and the MB removal efficiency remained higher than 95% after the iron oxides@HTCC was recycled 4 times.The magnetically recyclable iron oxides@HTCC may provide a solution for the treatment of wastewater from the textile industry.
基金Financial support for this study was jointly provided by the National Natural Science Foundation of China(Grant Nos.41421002and 41225008)MOST Special Fund from the State Key Laboratory of Continental Dynamics,Northwest UniversityProject for Key Innovative Research Team of Science and Technology in Shaanxi Province(Grant No.2013KCT-18)
文摘The Helanshan tectonic belt(HTB) is a major tectonic divide between the Alxa and Ordos blocks in the North China Craton. The geochronology and petrogenesis of the mafic dykes in the northern HTB are keys to understanding the tectonic evolution of this belt. The mafic dykes, intruded into the Neoarchean-Paleoproterozoic metamorphic basement, are mainly composed of diabase with a mineral assemblage of plagioclase(45%-60%), pyroxene(25%-35%), minor quartz and Fe-Ti oxides. The LA-ICPMS U-Pb analysis of zircon grains from representative dykes yield a weighted mean age of 206 ± 1.9 Ma, which represents the crystallization age of the dyke. The diabases show high contents of Fe_2 O_3~T(11.88-17.55 wt.%), low contents of SiO_2(45.65-50.95 wt.%) and MgO(3.31-5.50 wt.%) with low Mg#(=100×MgO/(MgO + FeO) atomic ration) of 33-44. They are characterized by enrichment of light rare earth elements(LREEs) and large ion lithophile elements(LILEs)(e.g., Rb, Ba and Pb), and slight depletion of high field strength elements(HFSEs). These features suggest that the magma has undergone extensive fractionation of olivine and pyroxene but only minor crustal contamination during its evolution. Their high Sm contents and La/Sm ratios, and low Sm/Yb ratios indicate that magma from which the dykes formed was derived from low degree(about 5%) partial melting of an enriched garnet + spinel lherzolite mantle source. Together with regional geology, these geochemical and geochronological data suggest that the mafic dykes in the HTB were formed in an intracontinental extensional setting during the late Triassic.
基金supported by the National Natural Science Foundation of China(31671625,31271669)the National Key Research and Development Program of China(2016YFD0300202)
文摘Optimized nitrogen(N)management can increase N-use efficiency in intercropping systems.Legume-nonlegume intercropping systems can reduce N input by exploiting biological N fixation by legumes.Measurement of N utilization can help in dissecting the mechanisms underlying N uptake and utilization in legume-nonlegume intercropping systems.An experiment was performed with three planting patterns:monoculture maize(MM),monoculture soybean(SS),and maize-soybean relay intercropping(IMS),and three N application levels:zero N(NN),reduced N(RN),and conventional N(CN)to investigate crop N uptake and utilization characteristics.N recovery efficiency and 15N recovery rate of crops were higher under RN than under CN,and those under RN were higher under intercropping than under the corresponding monocultures.Compared with MM,IMS showed a lower soil N-dependent rate(SNDR)in 2012.However,the SNDR of MM rapidly declined from 86.8%in 2012 to 49.4%in 2014,whereas that of IMS declined slowly from 75.4%in 2012 to 69.4%in 2014.The interspecific N competition rate(NCRms)was higher under RN than under CN,and increased yearly.Soybean nodule dry weight and nitrogenase activities were respectively 34.2%and 12.5%higher under intercropping than in monoculture at the beginning seed stage.The amount(Ndfa)and ratio(%Ndfa)of soybean N2 fixation were significantly greater under IS than under SS.In conclusion,N fertilizer was more efficiently used under RN than under CN;in particular,the relay intercropping system promoted N fertilizer utilization in comparison with the corresponding monocultures.An intercropping system helps to maintain soil fertility because interspecific N competition promotes biological N fixation by soybean by reducing N input.Thus,a maize-soybean relay intercropping system with reduced N application is sustainable and environmentally friendly.
基金supported by the State Key Program of National Natural Science Foundation of China(31530056)the National First-class Discipline Program of Food Science and Technology(JUFSTR20180102)the Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province,China.
文摘It is well known that the gut microbiota plays an extremely important role in modulating host physiological functions such as immunity and metabolic homeostasis.In recent years,accumulated evidence has revealed that the gut microbiota can regulate the functions of the central nervous system(CNS)through the gut-brain axis,which provides a novel insight into the interactions between the gut and brain.This review focuses on the molecular mechanism of the crosstalk between the gut microbiota and the brain via the gut-brain axis,and on the onset and development of neurological disorders triggered by gut microbiota dysbiosis.These topics are followed by a critical analysis of potential intervention strategies targeting gut microbiota dysbiosis,including the use of probiotics,prebiotics,synbiotics,and diets.While research on the microbiota-gut-brain axis is still in its relative infancy,clarifying the molecular mechanism that underlies how the gut microbiota regulates neurological functions not only holds the promise of revealing potentially novel pathogeneses of neurological disorders,but also may lead to the development of potential diagnosis biomarkers and intervention strategies targeting microbiota dysbiosis for neurological disorders.
基金supported by the National Natural Science Foundation of China project(61672067)Science and Technology Program of Beijing(Z151100002115040)
文摘Adverse weather has a considerable impact on the behavior of drivers,which puts vehicles and drivers in hazardous situations that can easily cause traffic accidents.This research examines how drivers'perceived risk changes during car following under different adverse weather conditions by using driving simulation experiment.An expressway road scenario was built in a driving simulator.Eleven types of weather conditions,including clear sky,four levels of fog,four levels of rain and two levels of snow,were designed.Furthermore,to simulate the carfollowing behavior,three car-following situations were designed according to the motion of the lead car.Seven car-following indicators were extracted based on risk homeostasis theory.Then,the entropy weight method was used to integrate the selected indicators into an index to represent the drivers'perceived risk.Multiple linear regression was applied to measure the influence of adverse weather conditions on perceived risk,and the coefficients were considered as indicators.The results demonstrate that both the weather conditions and road type have significant effects on car-following behavior.Drivers'perceived risk tends to increase with the worsening weather conditions.Under conditions of extremely poor visibility,such as heavy dense fog,the measured drivers'perceived risk is low due to the difficulties in vehicle operation and limited visibility.
基金Financial support for this study was jointly provided by the National Natural Science Foundation of China (Grant Nos. 41421002, 41225008, 41702231)Program for Changjiang Scholars and Innovative Research Team in University (Grant No. IRT1281)MOST Special Fund from the State Key Laboratory of Continental Dynamics, Northwest University, China
文摘The Chinese Altai in northwestern Xinjiang has numerous outcrops of granitoids which provide critical information on accretionary orogenic processes and crustal growth of the Central Asian Orogenic Belt.Zircon U-Pb ages, Hf-isotopic compositions and whole-rock geochemistry of monzogranite and granodiorites in the Qinghe County are employed to elucidate Paleozoic tectonics of the Chinese Altai. Granodiorites have crystallization ages of 424.6 ± 3.1 Ma(MSWD = 0.23) and 404.0 ± 3.4 Ma(MSWD = 0.18);monzogranite was emplaced in the early Permian with a crystallization age of 293.7 ± 4.6 Ma(MSWD = 1.06). Both granodiorites and monzogranite are I-type granites with A/CNK ratios of 0.92 -0.97 and 1.03 -1.06, respectively. They also show similar geochemical features of high HREE and Y contents, low Sr contents and Sr/Y ratios, as well as enrichment of Cs, Rb, Th and U, and depletion of Nb, Ta, P and Ti.These geochemical features indicate that the monzogranite and granodiorites were formed in an arc setting related to subduction. The gneissic monzogranites display high SiO_2 and K_2 O contents, and belong to the high-K calc-alkaline series. In the chondrite normalized REE distribution pattern, the monzogranite samples exhibit enrichment of LREE with strong negative Eu anomalies(σE u =0.44 -0.53), zircon εHf(t) values from +7.24 to +12.63 and two-stage Hf model ages of 463 -740 Ma. This suggests that the monzogranite was generated from the mixing of pelitic and mantle material. The granodiorite samples are calc-alkaline granites with lower contents of Si O_2 and Na_2 O + K_2 O, higher contents of TiO_2, Fe_2O_3~t, MgO and CaO compared to the monzogranite samples. They also show enrichment of LREE and moderate negative Eu anomalies(σE u= 0.54 =0.81), as well as slightly higher differentiation of LREE than that of HREE. The425 Ma granodiorite has zircon εHf(t) values from -0.51 to +1.98 and two-stage Hf model ages of 1133 -1240 Ma, whereas the 404 Ma granodiorite displays those of +2.52 to +7.50 and 816 -1071 Ma.Geochemistry and zircon Hf isotopic compositions indicate that granodiorites were formed by partial melting of juvenile lower crust. Together with regional geology and previous data, the geochemical and geochronological data of the monzogranite and granodiorites from this study suggest long-lived subduction and accretion along the Altai Orogen during ca. 425 -294 Ma.
基金financially supported by the National Natural Science Foundation of China(Nos.52074035 and 52008229)the Key Technologies Research and Develo pment Program,China(No.2020YFB0606200)。
文摘Circulating fluidized bed fly ash(CFBFA)is a solid waste product from circulating fluidized bed(CFB)boilers in power plants,and the storage of CFBFA is increasingly become an environmental problem.Previous scholars have made contributions to improve the resource utilization of CFBFA.Especially,ecological cement is prepared by CFBFA,which is more conducive to its large-scale utilization.In recent years,a lot of effort has been paid to improve the properties of ecological cement containing CFBFA.In this work,the physicochemical properties of CFBFA are introduced,and recent research progress on the mechanical,expansion,and rheological properties of CFBFA based ecological cement(CEC)is extensively reviewed.The problem of over-expansion of f-CaO is summarized,which limits the scale application of CFBFA in ecological cement.Hence,the challenge for f-CaO in CFBFA to compensate for cement volume shrinkage is proposed,which is beneficial to the utilization of CFBFA in ecological cement,and the reduction of CO_(2) emissions from the cement industry.In addition,the environmental performance,durability,and economy of CEC should be valued in future research,especially the environmental performance,because the CFBFA contains heavy metals,such as Cr,As,which may pollute groundwater.
文摘To overcome the current difficulties of high-precision machining and the high manufacturing and maintenance costs of spherical seals for deep-water drilling ball joints,a new spherical seal technique is proposed in this paper.The spherical seal is mainly composed of silicone rubber and polytetrafluoroethylene(PTFE).Rational structural design makes the seal independent from the ball and other components,making it easy to replace if leakage occurs at its surface.PTFE can elastically deform over a certain deformation range,which guarantees that two sealing surfaces fit tightly together.O-Ring and PTFE elasticity makes up for any lack of accuracy during spherical machining and decreases the machining precision requirements for spherical surfaces.Using a finite element technique and nonlinear theory,the performance of the spherical seal under the influence of various factors is determined.The results show that the spherical seal designed in this paper exhibits excellent sealing performance under lowtemperature and high-pressure conditions.The spherical seal,a combination of an O-ring and PTFE,has the advantages of cheap manufacturing and maintenance costs and excellent sealing performance.
文摘Global water security is a severe issue that threatens human health and well-being. Finding sustainable alternative water resources has become a matter of great urgency. For coastal urban areas, desalinated seawater could serve as a freshwater supply. However, since 20%-30% of the water supply is used for flushing waste from the city, seawater with simple treatment could also partly replace the use of freshwater. In this work, the freshwater saving potential and environmental impacts of the urban water system （water-wastewater closed loop） adopting seawater desalination, seawater for toilet flushing （SWTF）, or reclaimed water for toilet flushing （RWTF） are compared with those of a conventional freshwater system, through a life-cycle assessment and sensitivity analysis. The potential applications of these processes are also assessed. The results support the environmental sustainability of the SWTF approach, but its potential application depends on the coastal distance and effective population density of a city. Developed coastal cities with an effective population density exceeding 3000 persons.km-2 and located less than 30 km from the seashore （for the main pipe supplying seawater to the city） would benefit from applying SWTF, regardless of other impact parameters. By further applying the sulfate reduction, autotrophic denitrification, and nitrification integrated （SANI） process for wastewater treatment, the maximum distance from the seashore can be extended to 60 km. Considering that most modern urbanized cities fulfill these criteria, the next generation of water supply systems could consist of a freshwater supply coupled with a seawater supply for sustainable urban development.
基金This work was supported in part by the National Natural Science Foundation of China under Grant 51337001 and 51777136。
文摘The researches on the heat generation and dissipa-tion of the permanent magnet synchronous machines(PMSMs)are integrated problems involving multidisciplinary studies of electromagnetism,thermomechanics,and computational fluid dynamics.The governing equations of the multi-physical prob-lems are coupled and hard to be solved and illustrated.The high accuracy mathematical model in the algebraically integral con-servative forms of the coupled fields is established and computed in this paper.And the equation coupling with the fluid flow and the temperature variation is modified to improve the positive definiteness and the symmetry of the global stiffness matrix.The computational burden is thus reduced by the model modification.A 20kW 4500rpm permanent magnet synchronous machine(PMSM)is taken as the prototype,and the calculation results are validated by experimental ones.
基金funded by the German Science Foundation(DFG),grant KR590/94-1 to AK
文摘Magmatic zircon in high-grade metamorphic rocks is often characterized by complex textures as revealed by cathodoluminenscence （CL） that result from multiple episodes of recrystallization, over- growth, Pb-loss and modifications through fluid-induced disturbances of the crystal structure and the original U-Th-Pb isotopic systematics. Many of these features can be recognized in 2-dimensional CL images, and isotopic analysis of such domains using a high resolution ion-microprobe with only shallow penetration of the zircon surface may be able to reconstruct much of the magmatic and complex post- magmatic history of such grains. In particular it is generally possible to find original magmatic domains yielding concordant ages. In contrast, destructive techniques such as LA-ICP-MS consume a large volume, leave a deep crater in the target grain, and often sample heterogeneous domains that are not visible and thus often yield discordant results which are difficult to interpret. We provide examples of complex magmatic zircon from a southern Indian granulite terrane where SHRIMP lI and LA-ICP-MS analyses are compared. The SHRIMP data are shown to be more precise and reliable, and we caution against the use of LA-ICP-MS in deciphering the chronology of complex zircons from high-grade terranes.
基金supported by the Open Foundation of Jiangsu Engineering Center of Network Monitoring(Nanjing University of Information Science&Technology)(Grant No.KJR1509)the PAPD fundthe CICAEET fund
文摘Traditional watermark embedding schemes inevitably modify the data in a host audio signal and lead to the degradation of the host signal.In this paper,a novel audio zero-watermarking algorithm based on discrete wavelet transform(DWT),discrete cosine transform(DCT),and singular value decomposition(SVD) is presented.The watermark is registered by performing SVD on the coefficients generated through DWT and DCT to avoid data modification and host signal degradation.Simulation results show that the proposed zero-watermarking algorithm is strongly robust to common signal processing methods such as requantization,MP3 compression,resampling,addition of white Gaussian noise,and low-pass filtering.
基金supported by the Open Foundation of Jiangsu Engineering Center of Network Monitoring(Nanjing University of Information Science&Technology)(Grant No.KJR1509)the PAPD fundthe CICAEET fund
文摘Essential characteristics for watermark registration and detection without data modification can be used in anaudio zero-watermarking scheme.In this paper,a novel audio zero-watermarking scheme based on discrete wavelet transform(DWT) and discrete cosine transform(DCT) is presented.Thewatermark is registered by comparing the mean absolute values of the adjacent frame coefficients after DWT and DCT.Simulation results show that the proposed scheme is stronglyrobusttocommon attacks such as AWGN,downsampling,low-pass filtering,requantization,and MP3 compression.A performance analysis of the proposed scheme shows that all bit error rates after attacks are zero.
