Accurate assessment of postfire vegetation recovery is important for forest management and the conservation of species diversity.Topography is an important factor aff ecting vegetation recovery but whether species com...Accurate assessment of postfire vegetation recovery is important for forest management and the conservation of species diversity.Topography is an important factor aff ecting vegetation recovery but whether species composition varies with diff erent recovery stages and between valleys and slopes is unclear.Using fi eld data and a space-for-time substitution method,we quantifi ed species richness and diversity to obtain the successional trajectories of valleys and slopes.We surveyed the species of 10 burned areas from 1986 to 2010 in the Greater Khingan Mountains in northeastern China,and found that with increasing postfi re recovery time,species richness in both valleys and slopes gradually decreased.However,species richness in valleys was relatively higher.Shrubs recovered rapidly in the valleys,and species diversity maximized approximately 11 years after fi re.However,it maximized 17–18 years after fi re on the slopes.Numerous shade-tolerant species were present in the valleys 11 years after fi re but not until after 18 years on slopes.Larch appeared earlier than 11 years after fi re and its recovery was slow in the valleys but appeared quickly on slopes and established dominance early.Our study provides some new insights into vegetation succession after fi re at local scales.After fi re,the vegetation recovery processes diff er with topography and it aff ects the initial rate of recovery and species composition at diff erent successional stages.展开更多
The internal flow of a droplet in the nonlinear extensional flow field will exhibit more than two internal circulations with the variation of nonlinear intensity(E).In this paper,the effect of positions and sizes of i...The internal flow of a droplet in the nonlinear extensional flow field will exhibit more than two internal circulations with the variation of nonlinear intensity(E).In this paper,the effect of positions and sizes of internal circulations on internal mass transfer rate of a single spherical droplet in a nonlinear extensional flow field is studied and compared with that in a linear extensional flow field.The simulation results show that when E≥0,there are two symmetrical internal circulations in the droplet,which is the same with that in a linear extensional flow.The limit value of mass transfer rate Sh is 15,which is equal to that in a linear extensional flow,no matter how large E is.When E≤-3/7,the number of internal flow circulation of a droplet increase to four and the transfer rate Sh increases.When E=-1,the maximum internal transfer rate Sh equals 30 which is twice of that in a linear extensional flow.The generation of new flow circulations in droplets and the circulation positions will enhance mass transfer when E≤-3/7,which provides a new idea for enhancing the internal mass transfer rate of droplets.展开更多
Two sets of CCD photometric observations for contact binary TU Boo were obtained in 2020 and 2021.Different from its asymmetric light curves published from the literature,our BVRcIc-band curves show that the heights o...Two sets of CCD photometric observations for contact binary TU Boo were obtained in 2020 and 2021.Different from its asymmetric light curves published from the literature,our BVRcIc-band curves show that the heights of maximum are almost equal.These distortions of light curves possibly indicate that the components were active in past 25 yr,but they were stable in the last two years.For total-eclipse binary TU Boo,due to some star-spots on the surface of the components,the physical structure obtained by many investigators are different.Therefore,the symmetric multi-color light curves in 2020,2021 are important for understanding configuration and evolution of this system.By using the Wilson–Devinney program,it is confirmed that TU Boo is an A-type shallow-contact binary with the temperature difference ofΔT=152 K and fill-out of f=14.67%.In the O−C diagram of orbital period analysis,a cyclic oscillation superimposed on a continuous decrease was determined.The long-term decreasing is often explained by the mass transfer from the more massive star to less massive one,this system will evolve into a deeper contact binary with time.The cyclic oscillations computed from much more CCD times of light minimum maybe result from the light-travel time effect via the presence of a third body.These characters of structure,evolution and ternary belong to typical A-type W UMa binaries with spectral G.展开更多
Sensors produce a large amount of multivariate time series data to record the states of Internet of Things(IoT)systems.Multivariate time series timestamp anomaly detection(TSAD)can identify timestamps of attacks and m...Sensors produce a large amount of multivariate time series data to record the states of Internet of Things(IoT)systems.Multivariate time series timestamp anomaly detection(TSAD)can identify timestamps of attacks and malfunctions.However,it is necessary to determine which sensor or indicator is abnormal to facilitate a more detailed diagnosis,a process referred to as fine-grained anomaly detection(FGAD).Although further FGAD can be extended based on TSAD methods,existing works do not provide a quantitative evaluation,and the performance is unknown.Therefore,to tackle the FGAD problem,this paper first verifies that the TSAD methods achieve low performance when applied to the FGAD task directly because of the excessive fusion of features and the ignoring of the relationship’s dynamic changes between indicators.Accordingly,this paper proposes a mul-tivariate time series fine-grained anomaly detection(MFGAD)framework.To avoid excessive fusion of features,MFGAD constructs two sub-models to independently identify the abnormal timestamp and abnormal indicator instead of a single model and then combines the two kinds of abnormal results to detect the fine-grained anomaly.Based on this framework,an algorithm based on Graph Attention Neural Network(GAT)and Attention Convolutional Long-Short Term Memory(A-ConvLSTM)is proposed,in which GAT learns temporal features of multiple indicators to detect abnormal timestamps and A-ConvLSTM captures the dynamic relationship between indicators to identify abnormal indicators.Extensive simulations on a real-world dataset demonstrate that the proposed algorithm can achieve a higher F1 score and hit rate than the extension of existing TSAD methods with the benefit of two independent sub-models for timestamp and indicator detection.展开更多
Low temperature cracking(LTC)distress on pavement seriously affects road life.This paper finished a literature review of the research on the mechanism of LTC of asphalt composites(asphalt composites refers to asphalt ...Low temperature cracking(LTC)distress on pavement seriously affects road life.This paper finished a literature review of the research on the mechanism of LTC of asphalt composites(asphalt composites refers to asphalt binder and asphalt mixture in this article),test methods,factors contributing to LTC,measures to prevent and control the distress,and prediction of LTC in asphalt pavements.The following conclusions were obtained:the cracking mechanism of asphalt mixtures needs to be further revealed by means of simulation at the micro level,the BBR and 4 mm plate test(by DSR)methods are currently optimal,and a correlation between asphalt and asphalt mixture evaluation indexes needs to be established.Sensitivity analyses are needed for the factors affecting LTC of asphalt mixtures.It is necessary to calculate the contribution of each factor to the LTC of asphalt mixtures.The aim is to propose targeted improvement measures for the most unfavourable factors,as well as to carry out research and development of key materials for anti-cracking.Measures for the prevention and control of LTC of asphalt pavement are analyzed and discussed.Existing researches on the prediction of LTC of asphalt pavements is discussed.It is necessary to analyse the mechanical response of asphalt pavement,the damage process and the sensitivity of anti-cracking parameters on the basis of considering the complex geometrical characteristics and material properties of asphalt pavement materials.Finally,the mechanism of LTC,evaluation methods,factors influencing LTC,and remedial measures for asphalt composites were summarized,and future research prospects were suggested.This paper provides theoretical support for the further solution of LTC distress of asphalt pavement,which is effective on the improvement of pavement life.展开更多
Three types of scanning strategies,including the chessboard scanning strategy,the zigzag scanning strategy and the remelting scanning strategy,were conducted to study the effects of scanning strategies on surface morp...Three types of scanning strategies,including the chessboard scanning strategy,the zigzag scanning strategy and the remelting scanning strategy,were conducted to study the effects of scanning strategies on surface morphology,microstructure,mechanical properties and the grain orientation of selective laser melted pure tungsten.The results showed that the pores and cracks were main defects in SLM-processed tungsten parts.The pores could be eliminated using the remelting scanning strategy.However,the cracks seemed to be inevitable regardless of the applied scanning strategies.The microstructures of SLM-processed tungsten were columnar grains and showed strong epitaxial growth along the building direction.A compressive strength of 923 MPa with an elongation of 7.7%was obtained when the zigzag scanning strategy was applied,which was the highest among the three scanning strategies.By changing the scanning strategies,the texture of SLM-processed tungsten in the direction of processing could be changed.展开更多
Acanthopanax trifoliatus( L.) Merr is a common traditional Chinese herbal medicine in central and southern regions of China. It has high medicinal and edible value and mainly contains flavonoids,polysaccharides,saponi...Acanthopanax trifoliatus( L.) Merr is a common traditional Chinese herbal medicine in central and southern regions of China. It has high medicinal and edible value and mainly contains flavonoids,polysaccharides,saponins and volatile components. Its active extracts have antioxidant,anti-inflammatory,anti-fatigue,and analgesic effects. From the biological characteristics,effective chemical components,extraction methods,cultivation techniques,pharmacological effects,toxicological activities,and product development status,this paper reviewed in detail the research status of A. trifoliatus in China and abroad,to provide a scientific basis for in-depth research and development,and utilization of A. trifoliatus.展开更多
Objective:To study the ultrasound features of carotid atherosclerosis in patients with coronary heart disease and their correlation with disease severity. Methods:180 patients with coronary heart disease treated in ou...Objective:To study the ultrasound features of carotid atherosclerosis in patients with coronary heart disease and their correlation with disease severity. Methods:180 patients with coronary heart disease treated in our hospital between December 2010 and December 2015 were collected as observation group and divided into single-vessel disease group (n=50), double-vessel disease group (n=72) and triple-vessel disease group (n=58) according to the degree of coronary artery stenosis;50 healthy subjects receiving physical examination in our hospital during the same period were selected as control group. Carotid ultrasound was used to measure carotid atherosclerosis parameters, cardiac color Doppler ultrasound was used to detect cardiac function parameters, enzyme-linked immunosorbent assay (ELISA) was used to detect serum endothelial function indexes, and Pearson test was used to analyze the correlation between carotid ultrasound parameters and the cardiac function as well as endothelial function. Results:Carotid ultrasound parameters stiffness (β), elastic modulus (Ep), arterial compliance (AC) and pulse wave velocity (PWVβ) value of observation group were higher than those of control group, and with the increase of coronary artery lesion severity, the changes ofβ, Ep, AC and PWVβvalue increased (P<0.05);cardiac function parameters left ventricular end-diastolic diameter (LVEDD) and left ventricular end-systolic diameter (LVESD) value of observation group were higher than those of control group while left ventricular ejection fraction (LVEF) value was lower than that of control group, and with the increase of coronary artery lesion severity, the changes of LVEDD, LVESD and LVEF value increased (P<0.05);endothelial function indexes endothelin-1 (ET-1) and von willebrand factor (vWF) levels of observation group were higher than those of control group while nitric oxide (NO) level was lower than that of control group, and with the increase of coronary artery lesion severity, the changes of ET-1, vWF and NO levels increased (P<0.05). Carotid ultrasound parameterβ, Ep, AC and PWVβvalue in patients with coronary heart disease were directly correlated with the levels of cardiac function parameters and endothelial function indexes. Conclusions:The ultrasound parameter levels of carotid atherosclerosis in patients with coronary heart disease are directly correlated with the disease severity and can be used as the noninvasive and reliable means for early judgment of the disease.展开更多
The decomposition of coarse woody debris(CWD)affects the energy flow and nutrient cycling in forest ecosystems.Previous studies on CWD have focused on the input,decomposition,reserve dynamics,and CWD functions,but coa...The decomposition of coarse woody debris(CWD)affects the energy flow and nutrient cycling in forest ecosystems.Previous studies on CWD have focused on the input,decomposition,reserve dynamics,and CWD functions,but coarse woody debris decomposition is complex and the results from different regions vary considerably.It is not clear which factors affect decay rate(k),especially at different decomposition stages.In this study,a single-exponential decay model was used to analyze the characteristics of CWD decomposition in Larix gmelinii forests over the 33 years following a fire in the Greater Khingan Mountains.The results show that the decay rate of coarse woody debris was positively correlated to decay class.The average decomposition rate was 0.019,and 41 years and 176 years are needed for a 50%and 95%mass loss,respectively.CWD nutrient content,density,and water content could explain the variance in the decay rate(~42%)of the decay factors such as amount of leaching,degree of fragmentation,respiration of the debris,and biotransformation,and varied significantly between different decay classes.Using the space-time substitution method,this study arranged the coarse woody debris of different mortality times to form a 33 year chronosequence which revealed the decomposition process.It was concluded that the decay rate was mainly explained by structural component of the debris and its nitrogen and water contents.This paper quantifies the indicators affecting CWD decay to explain the decomposition process.展开更多
Cavitation inside a torque converter induces noise,vibration and even failure,and these effects have been disregarded in previous torque converter design processes.However,modern torque converter applications require ...Cavitation inside a torque converter induces noise,vibration and even failure,and these effects have been disregarded in previous torque converter design processes.However,modern torque converter applications require attention to this issue because of its high-speed and high-capacity requirements.Therefore,this study investigated the cavitation effect on a torque converter using both numerical and experimental methods with an emphasis on the influence of the charging oil feed location and charge pressure.Computational fluid dynamics(CFD)models were established to simulate the transient cavitation behaviour in the torque converter using different charging oil pressures and inlet arrangements and testing against a base case to validate the results.The CFD results suggested that cavitating bubbles mainly takes place in the stator of the torque converter.The transient cavitation CFD model yielded good agreement with the experimental data,with an error of 7.6%in the capacity constant and 7.4%in the torque ratio.Both the experimental and numerical studies showed that cavitation induced severe capacity degradation,and that the charge pressure and charging oil configuration significantly affects both the overall hydrodynamic performance and the fluid behaviour inside the torque converter because of cavitation.Increasing the charge pressure and charging the oil from the turbine-stator clearance were found to suppress cavitation development and reduce performance degradation,especially in terms of the capacity constant.This study revealed the fluid field mechanism behind the influence of charging oil conditions on torque converter cavitation behaviour,providing practical guidelines for suppressing cavitation in torque converter.展开更多
This work systematically simulates the external mass transfer from/to a spherical drop and solid particle suspended in a nonlinear uniaxial extensional creeping flow.The mass transfer problem is governed by three dime...This work systematically simulates the external mass transfer from/to a spherical drop and solid particle suspended in a nonlinear uniaxial extensional creeping flow.The mass transfer problem is governed by three dimensionless parameters:the viscosity ratio(λ),the Peclet number(Pe),and the nonlinear intensity of the flow(E).The existing mass transfer theory,valid for very large Peclet numbers only,is expanded,by numerical simulations,to include a much larger range of Peclet numbers(1≤Pe≤105).The simulation results show that the dimensionless mass transfer rate,expressed as the Sherwood number(5 h),agrees well with the theoretical results at the convection-dominated regime(Pe>103).Only when E>5/4,the simulated Sh for a solid sphere in the nonlinear uniaxial extensional flow is larger than theoretical results because the theory neglects the effect of the vortex formed outside the particle on the rate of mass transfer.Empirical correlations are proposed to predict the influence of the dimensionless governing parameters(λ,Pe,E)on the Sherwood number(Sh).The maximum deviations of all empirical correlations are less than 15%when compared to the numerical simulated results.展开更多
Background: In the previous study, we established an ischemia-prone gerbil population(IG), which was selectively bred to increase the incidence of unilateral carotid arterial occlusion(UCO)-induced ischemia in Mongoli...Background: In the previous study, we established an ischemia-prone gerbil population(IG), which was selectively bred to increase the incidence of unilateral carotid arterial occlusion(UCO)-induced ischemia in Mongolian gerbils. However, if the characteristics of ischemia model in IG are the same as those in general gerbils(GG), and if the neurological symptoms are associated with the neurological insults in IG is still unclear.Methods: In the present study, we evaluated the UCO model in IG by analyzing neurological symptoms, neurological injury in the hippocampal CA1 region and compared with GG.Results: The data showed that the ratios of neurological symptom scores ≥ 2 in the IG and GG groups were 65.0% vs 30.0%, respectively, and were significantly different(P <.01).The neuronal damage following a UCO ischemic insult in the IG group was more severe compared to the GG group. There was a high correlation between the neurological insults' scale and the neurological symptom score in the IG and GG groups(r =.979 and.943 in the IG and GG groups, respectively). In animals with mild neurological symptom scores(2 and 3), the neuronal insults were significantly different between female and male gerbils in both IG and GG.Conclusion: Our findings suggest that IG population would likely be more advantageous to establish an ischemic model.展开更多
An i-Line chemically amplified(ICA)thick film positive resist is reported in this paper.The impact of process conditions on photoresist performance was investigated.Pre-apply bake temperature and post exposure bake te...An i-Line chemically amplified(ICA)thick film positive resist is reported in this paper.The impact of process conditions on photoresist performance was investigated.Pre-apply bake temperature and post exposure bake temperature affect acid diffusion and deblocking reactions,thus playing an integral role in defining the resist profile.Both pre-apply bake delay and post exposure delay(PED)affect critical dimension(CD)variation,but PED is more sensitive to contact with airborne contaminants.Different polymers and different photo-acid generators(PAG)are also illustrated in this work.By optimizing the structure and concentration of key components,an ICA resist with good environment stability and excellent lithographic performance was demonstrated.展开更多
Since it was put forward in 1995,musculo-dural bridge has been widely concerned.With the deepening of research,the structure,shape and physiological functions of musculo-dural bridge are gradually known.Previous studi...Since it was put forward in 1995,musculo-dural bridge has been widely concerned.With the deepening of research,the structure,shape and physiological functions of musculo-dural bridge are gradually known.Previous studies have found that the musculo-dural bridge between muscle and dura mater can not only transfer proprioception,prevent the rupture of dura mater and ensure the normal flow of cerebrospinal fluid,but also be related to chronic cervicogenic headache.Therefore,this article mainly discusses the composition of musculo-dural bridge complex and its relationship with chronic cervicogenic headache,so as to provide a new diagnosis and treatment idea for the occurrence,development and treatment of related diseases in clinic.展开更多
S-scheme heterostructure photocatalysts utilize the synergistic and superposition effects of materials,ef-fectively separating electrons and holes,maintaining strong redox capacity,and addressing issues en-countered b...S-scheme heterostructure photocatalysts utilize the synergistic and superposition effects of materials,ef-fectively separating electrons and holes,maintaining strong redox capacity,and addressing issues en-countered by current photocatalytic reactions.This review explores the origins and unique benefits of S-scheme heterojunctions.Specifically,we summarized and discussed the effects of different dimensions of semiconductors constituting S-scheme heterojunctions and the similarities and differences in elec-tron transfer processes when constructing heterojunctions.Additionally,we analyzed several methods for proving the formation of S-scheme heterojunctions and the electron transfer process,both directly and indirectly.Finally,we review the applications of S-scheme heterojunctions in various fields of photo-catalysis,including photocatalytic water splitting,pollution degradation,CO_(2) reduction and other related photocatalytic applications.Our hope is that this review will provide an essential reference for the devel-opment and application of S-scheme heterojunction photocatalysis.展开更多
Background:The Mongolian gerbil is an excellent laboratory animal for preparing the cerebral ischemia model due to its inherent deficiency in the circle of Willis.However,the low incidence and unpredictability of symp...Background:The Mongolian gerbil is an excellent laboratory animal for preparing the cerebral ischemia model due to its inherent deficiency in the circle of Willis.However,the low incidence and unpredictability of symptoms are caused by numerous complex variant types of the circle.Additionally,the lack of an evaluation system for the cer-ebral ischemia/reperfusion(I/R)model of gerbils has shackled the application of this model.Methods:We created a symptom-oriented principle and detailed neurobehavioral scoring criteria.At different time points of reperfusion,we analyzed the alteration in locomotion by rotarod test and grip force score,infarct volume by triphenyltetrazo-lium chloride(TTC)staining,neuron loss using Nissl staining,and histological charac-teristics using hematoxylin-eosin(H&E)straining.Results:With a successful model rate of 56%,32 of the 57 gerbils operated by our method harbored typical features of cerebral I/R injury,and the mortality rate in the male gerbils was significantly higher than that in the female gerbils.The suc-cessfully prepared I/R gerbils demonstrated a significant reduction in motility and grip strength at 1 day after reperfusion;formed obvious infarction;exhibited typi-cal pathological features,such as tissue edema,neuronal atrophy and death,and vacuolated structures;and were partially recovered with the extension of reperfu-sion time.Conclusion:This study developed a new method for the unilateral common carotid artery ligation I/R model of gerbil and established a standardized evaluation system for this model,which could provide a new cerebral I/R model of gerbils with more practical applications.展开更多
A new HPV-16/18 bivalent vaccine expressed by the Escherichia coli has been proven to be efficacious in adult women.A randomized,immunogenicity noninferiority study of this candidate vaccine was conducted in December ...A new HPV-16/18 bivalent vaccine expressed by the Escherichia coli has been proven to be efficacious in adult women.A randomized,immunogenicity noninferiority study of this candidate vaccine was conducted in December 2015 in China.Girls aged 9–14 years were randomized to receive 2 doses at months 0 and 6(n=301)or 3 doses at months 0,1 and 6(n=304).Girls aged 15–17 years(n=149)and women aged 18–26 years(n=225)received 3 doses.The objectives included noninferiority analysis of the IgG geometric mean concentration(GMC)ratio(95%CI,lower bound>0.5)to HPV-16 and HPV-18 at month 7 in girls compared with women.In the per-protocol set,the GMC ratio of IgG was noninferior for girls aged 9–17 years receiving 3 doses compared with women(1.76(95%CI,1.56,1.99)for HPV-16 and 1.93(95%CI,1.69,2.21)for HPV-18)and noninferior for girls aged 9–14 years receiving 2 doses compared with women(1.45(95%CI,1.25,1.62)for HPV-16 and 1.17(95%CI,1.02,1.33)for HPV-18).Noninferiority was also demonstrated for neutralizing antibodies.The immunogenicity of the HPV vaccine in girls receiving 3 or 2 doses was noninferior compared with that in young adult women.展开更多
基金funded by the National Natural Science Foundation of China(No.41871103).
文摘Accurate assessment of postfire vegetation recovery is important for forest management and the conservation of species diversity.Topography is an important factor aff ecting vegetation recovery but whether species composition varies with diff erent recovery stages and between valleys and slopes is unclear.Using fi eld data and a space-for-time substitution method,we quantifi ed species richness and diversity to obtain the successional trajectories of valleys and slopes.We surveyed the species of 10 burned areas from 1986 to 2010 in the Greater Khingan Mountains in northeastern China,and found that with increasing postfi re recovery time,species richness in both valleys and slopes gradually decreased.However,species richness in valleys was relatively higher.Shrubs recovered rapidly in the valleys,and species diversity maximized approximately 11 years after fi re.However,it maximized 17–18 years after fi re on the slopes.Numerous shade-tolerant species were present in the valleys 11 years after fi re but not until after 18 years on slopes.Larch appeared earlier than 11 years after fi re and its recovery was slow in the valleys but appeared quickly on slopes and established dominance early.Our study provides some new insights into vegetation succession after fi re at local scales.After fi re,the vegetation recovery processes diff er with topography and it aff ects the initial rate of recovery and species composition at diff erent successional stages.
基金supported by the National Key Research and Development Program of China(2021YFC2902502)the National Natural Science Foundation of China(22078320,22035007)+4 种基金the NSFC-EU project(31961133018)the Shandong Provincial Key Research and Development Program(2022CXGC020106)the Shandong Key Research and Development Program(International Cooperation Office)(2019GHZ018)the Shandong Province Postdoctoral Innovative Talents Support Plan(SDBX2020018)the External Cooperation Program of BIC,Chinese Academy of Sciences(122111KYSB20190032)。
文摘The internal flow of a droplet in the nonlinear extensional flow field will exhibit more than two internal circulations with the variation of nonlinear intensity(E).In this paper,the effect of positions and sizes of internal circulations on internal mass transfer rate of a single spherical droplet in a nonlinear extensional flow field is studied and compared with that in a linear extensional flow field.The simulation results show that when E≥0,there are two symmetrical internal circulations in the droplet,which is the same with that in a linear extensional flow.The limit value of mass transfer rate Sh is 15,which is equal to that in a linear extensional flow,no matter how large E is.When E≤-3/7,the number of internal flow circulation of a droplet increase to four and the transfer rate Sh increases.When E=-1,the maximum internal transfer rate Sh equals 30 which is twice of that in a linear extensional flow.The generation of new flow circulations in droplets and the circulation positions will enhance mass transfer when E≤-3/7,which provides a new idea for enhancing the internal mass transfer rate of droplets.
基金sponsored by Natural Science Foundation of Xinjiang Uygur Autonomous Region (No.2022DO1A164)the Joint Research Found (No.U1831109)in Astronomy under cooperative agreement between the National Natural Science Foundation of China (NSFC)and Chinese Academy of Sciences (CAS)the Natural Science Foundation of Shandong Province (No.ZR2020QA048)。
文摘Two sets of CCD photometric observations for contact binary TU Boo were obtained in 2020 and 2021.Different from its asymmetric light curves published from the literature,our BVRcIc-band curves show that the heights of maximum are almost equal.These distortions of light curves possibly indicate that the components were active in past 25 yr,but they were stable in the last two years.For total-eclipse binary TU Boo,due to some star-spots on the surface of the components,the physical structure obtained by many investigators are different.Therefore,the symmetric multi-color light curves in 2020,2021 are important for understanding configuration and evolution of this system.By using the Wilson–Devinney program,it is confirmed that TU Boo is an A-type shallow-contact binary with the temperature difference ofΔT=152 K and fill-out of f=14.67%.In the O−C diagram of orbital period analysis,a cyclic oscillation superimposed on a continuous decrease was determined.The long-term decreasing is often explained by the mass transfer from the more massive star to less massive one,this system will evolve into a deeper contact binary with time.The cyclic oscillations computed from much more CCD times of light minimum maybe result from the light-travel time effect via the presence of a third body.These characters of structure,evolution and ternary belong to typical A-type W UMa binaries with spectral G.
基金supported in part by the National Natural Science Foundation of China under Grant 62272062the Researchers Supporting Project number.(RSP2023R102)King Saud University+5 种基金Riyadh,Saudi Arabia,the Open Research Fund of the Hunan Provincial Key Laboratory of Network Investigational Technology under Grant 2018WLZC003the National Science Foundation of Hunan Province under Grant 2020JJ2029the Hunan Provincial Key Research and Development Program under Grant 2022GK2019the Science Fund for Creative Research Groups of Hunan Province under Grant 2020JJ1006the Scientific Research Fund of Hunan Provincial Transportation Department under Grant 202143the Open Fund of Key Laboratory of Safety Control of Bridge Engineering,Ministry of Education(Changsha University of Science Technology)under Grant 21KB07.
文摘Sensors produce a large amount of multivariate time series data to record the states of Internet of Things(IoT)systems.Multivariate time series timestamp anomaly detection(TSAD)can identify timestamps of attacks and malfunctions.However,it is necessary to determine which sensor or indicator is abnormal to facilitate a more detailed diagnosis,a process referred to as fine-grained anomaly detection(FGAD).Although further FGAD can be extended based on TSAD methods,existing works do not provide a quantitative evaluation,and the performance is unknown.Therefore,to tackle the FGAD problem,this paper first verifies that the TSAD methods achieve low performance when applied to the FGAD task directly because of the excessive fusion of features and the ignoring of the relationship’s dynamic changes between indicators.Accordingly,this paper proposes a mul-tivariate time series fine-grained anomaly detection(MFGAD)framework.To avoid excessive fusion of features,MFGAD constructs two sub-models to independently identify the abnormal timestamp and abnormal indicator instead of a single model and then combines the two kinds of abnormal results to detect the fine-grained anomaly.Based on this framework,an algorithm based on Graph Attention Neural Network(GAT)and Attention Convolutional Long-Short Term Memory(A-ConvLSTM)is proposed,in which GAT learns temporal features of multiple indicators to detect abnormal timestamps and A-ConvLSTM captures the dynamic relationship between indicators to identify abnormal indicators.Extensive simulations on a real-world dataset demonstrate that the proposed algorithm can achieve a higher F1 score and hit rate than the extension of existing TSAD methods with the benefit of two independent sub-models for timestamp and indicator detection.
基金financially supported by National Key R&D Program of China(2022YFE0137300)National Natural Science Foundation of China(52078018).
文摘Low temperature cracking(LTC)distress on pavement seriously affects road life.This paper finished a literature review of the research on the mechanism of LTC of asphalt composites(asphalt composites refers to asphalt binder and asphalt mixture in this article),test methods,factors contributing to LTC,measures to prevent and control the distress,and prediction of LTC in asphalt pavements.The following conclusions were obtained:the cracking mechanism of asphalt mixtures needs to be further revealed by means of simulation at the micro level,the BBR and 4 mm plate test(by DSR)methods are currently optimal,and a correlation between asphalt and asphalt mixture evaluation indexes needs to be established.Sensitivity analyses are needed for the factors affecting LTC of asphalt mixtures.It is necessary to calculate the contribution of each factor to the LTC of asphalt mixtures.The aim is to propose targeted improvement measures for the most unfavourable factors,as well as to carry out research and development of key materials for anti-cracking.Measures for the prevention and control of LTC of asphalt pavement are analyzed and discussed.Existing researches on the prediction of LTC of asphalt pavements is discussed.It is necessary to analyse the mechanical response of asphalt pavement,the damage process and the sensitivity of anti-cracking parameters on the basis of considering the complex geometrical characteristics and material properties of asphalt pavement materials.Finally,the mechanism of LTC,evaluation methods,factors influencing LTC,and remedial measures for asphalt composites were summarized,and future research prospects were suggested.This paper provides theoretical support for the further solution of LTC distress of asphalt pavement,which is effective on the improvement of pavement life.
基金the financial support by Science Challenge Project(Nos.TZ2018006-0301-02 and TZ2018006-0303-03)National Natural Science Foundation of China(No.51735005)National Natural Science Foundation of China for Creative Research Groups(Grant No.51921003)。
文摘Three types of scanning strategies,including the chessboard scanning strategy,the zigzag scanning strategy and the remelting scanning strategy,were conducted to study the effects of scanning strategies on surface morphology,microstructure,mechanical properties and the grain orientation of selective laser melted pure tungsten.The results showed that the pores and cracks were main defects in SLM-processed tungsten parts.The pores could be eliminated using the remelting scanning strategy.However,the cracks seemed to be inevitable regardless of the applied scanning strategies.The microstructures of SLM-processed tungsten were columnar grains and showed strong epitaxial growth along the building direction.A compressive strength of 923 MPa with an elongation of 7.7%was obtained when the zigzag scanning strategy was applied,which was the highest among the three scanning strategies.By changing the scanning strategies,the texture of SLM-processed tungsten in the direction of processing could be changed.
基金Supported by Joint Fund Project of Guizhou Provincial Department of Science and Technology(Qian Ke He LH Zi[2015]7716)Open Fund Project for Development Engineering Research Center of National Medicinal Plant Resources of Colleges and Universities in Guizhou Province(Qian Jiao He KY Zi[2014]227)
文摘Acanthopanax trifoliatus( L.) Merr is a common traditional Chinese herbal medicine in central and southern regions of China. It has high medicinal and edible value and mainly contains flavonoids,polysaccharides,saponins and volatile components. Its active extracts have antioxidant,anti-inflammatory,anti-fatigue,and analgesic effects. From the biological characteristics,effective chemical components,extraction methods,cultivation techniques,pharmacological effects,toxicological activities,and product development status,this paper reviewed in detail the research status of A. trifoliatus in China and abroad,to provide a scientific basis for in-depth research and development,and utilization of A. trifoliatus.
文摘Objective:To study the ultrasound features of carotid atherosclerosis in patients with coronary heart disease and their correlation with disease severity. Methods:180 patients with coronary heart disease treated in our hospital between December 2010 and December 2015 were collected as observation group and divided into single-vessel disease group (n=50), double-vessel disease group (n=72) and triple-vessel disease group (n=58) according to the degree of coronary artery stenosis;50 healthy subjects receiving physical examination in our hospital during the same period were selected as control group. Carotid ultrasound was used to measure carotid atherosclerosis parameters, cardiac color Doppler ultrasound was used to detect cardiac function parameters, enzyme-linked immunosorbent assay (ELISA) was used to detect serum endothelial function indexes, and Pearson test was used to analyze the correlation between carotid ultrasound parameters and the cardiac function as well as endothelial function. Results:Carotid ultrasound parameters stiffness (β), elastic modulus (Ep), arterial compliance (AC) and pulse wave velocity (PWVβ) value of observation group were higher than those of control group, and with the increase of coronary artery lesion severity, the changes ofβ, Ep, AC and PWVβvalue increased (P<0.05);cardiac function parameters left ventricular end-diastolic diameter (LVEDD) and left ventricular end-systolic diameter (LVESD) value of observation group were higher than those of control group while left ventricular ejection fraction (LVEF) value was lower than that of control group, and with the increase of coronary artery lesion severity, the changes of LVEDD, LVESD and LVEF value increased (P<0.05);endothelial function indexes endothelin-1 (ET-1) and von willebrand factor (vWF) levels of observation group were higher than those of control group while nitric oxide (NO) level was lower than that of control group, and with the increase of coronary artery lesion severity, the changes of ET-1, vWF and NO levels increased (P<0.05). Carotid ultrasound parameterβ, Ep, AC and PWVβvalue in patients with coronary heart disease were directly correlated with the levels of cardiac function parameters and endothelial function indexes. Conclusions:The ultrasound parameter levels of carotid atherosclerosis in patients with coronary heart disease are directly correlated with the disease severity and can be used as the noninvasive and reliable means for early judgment of the disease.
基金This research was funded by the National Key Research and Development Projects,Grant Number 2018YFE0207800the National Natural Science Foundation of China,Grant Number 41871103.
文摘The decomposition of coarse woody debris(CWD)affects the energy flow and nutrient cycling in forest ecosystems.Previous studies on CWD have focused on the input,decomposition,reserve dynamics,and CWD functions,but coarse woody debris decomposition is complex and the results from different regions vary considerably.It is not clear which factors affect decay rate(k),especially at different decomposition stages.In this study,a single-exponential decay model was used to analyze the characteristics of CWD decomposition in Larix gmelinii forests over the 33 years following a fire in the Greater Khingan Mountains.The results show that the decay rate of coarse woody debris was positively correlated to decay class.The average decomposition rate was 0.019,and 41 years and 176 years are needed for a 50%and 95%mass loss,respectively.CWD nutrient content,density,and water content could explain the variance in the decay rate(~42%)of the decay factors such as amount of leaching,degree of fragmentation,respiration of the debris,and biotransformation,and varied significantly between different decay classes.Using the space-time substitution method,this study arranged the coarse woody debris of different mortality times to form a 33 year chronosequence which revealed the decomposition process.It was concluded that the decay rate was mainly explained by structural component of the debris and its nitrogen and water contents.This paper quantifies the indicators affecting CWD decay to explain the decomposition process.
基金National Natural Science Foundation of China(Grant Nos.51805027,51475041)Beijing Institute of Technology Research Fund Program for Young Scholars(Grant No.3030011181804)Vehicular Transmission Key Laboratory Fund.
文摘Cavitation inside a torque converter induces noise,vibration and even failure,and these effects have been disregarded in previous torque converter design processes.However,modern torque converter applications require attention to this issue because of its high-speed and high-capacity requirements.Therefore,this study investigated the cavitation effect on a torque converter using both numerical and experimental methods with an emphasis on the influence of the charging oil feed location and charge pressure.Computational fluid dynamics(CFD)models were established to simulate the transient cavitation behaviour in the torque converter using different charging oil pressures and inlet arrangements and testing against a base case to validate the results.The CFD results suggested that cavitating bubbles mainly takes place in the stator of the torque converter.The transient cavitation CFD model yielded good agreement with the experimental data,with an error of 7.6%in the capacity constant and 7.4%in the torque ratio.Both the experimental and numerical studies showed that cavitation induced severe capacity degradation,and that the charge pressure and charging oil configuration significantly affects both the overall hydrodynamic performance and the fluid behaviour inside the torque converter because of cavitation.Increasing the charge pressure and charging the oil from the turbine-stator clearance were found to suppress cavitation development and reduce performance degradation,especially in terms of the capacity constant.This study revealed the fluid field mechanism behind the influence of charging oil conditions on torque converter cavitation behaviour,providing practical guidelines for suppressing cavitation in torque converter.
基金support and helpful insight.This work was supported by the National Key Research and Development Program(2021YFC2902502)the National Natu-ral Science Foundation of China(21938009,91934301,22078320)+5 种基金the Major Scientific and Technological Innovation Projects in Shan-dong Province(2019JZZY010302)the Shandong Key Research and Development Program(International Cooperation Office)(2019GHZ018)the Shandong Province Postdoctoral Innovative Talents Support Plan(SDBX2020018)the External Cooperation Program of BIC,Chinese Academy of Sciences(122111KYSB20190032)Chemistry and Chemical Engineering Guangdong Laboratory(1922006)GHfund B(202107021062).
文摘This work systematically simulates the external mass transfer from/to a spherical drop and solid particle suspended in a nonlinear uniaxial extensional creeping flow.The mass transfer problem is governed by three dimensionless parameters:the viscosity ratio(λ),the Peclet number(Pe),and the nonlinear intensity of the flow(E).The existing mass transfer theory,valid for very large Peclet numbers only,is expanded,by numerical simulations,to include a much larger range of Peclet numbers(1≤Pe≤105).The simulation results show that the dimensionless mass transfer rate,expressed as the Sherwood number(5 h),agrees well with the theoretical results at the convection-dominated regime(Pe>103).Only when E>5/4,the simulated Sh for a solid sphere in the nonlinear uniaxial extensional flow is larger than theoretical results because the theory neglects the effect of the vortex formed outside the particle on the rate of mass transfer.Empirical correlations are proposed to predict the influence of the dimensionless governing parameters(λ,Pe,E)on the Sherwood number(Sh).The maximum deviations of all empirical correlations are less than 15%when compared to the numerical simulated results.
基金Key Projects in the National Science&Technology Pillar Program,Grant/Award Number:2015BAI09B01
文摘Background: In the previous study, we established an ischemia-prone gerbil population(IG), which was selectively bred to increase the incidence of unilateral carotid arterial occlusion(UCO)-induced ischemia in Mongolian gerbils. However, if the characteristics of ischemia model in IG are the same as those in general gerbils(GG), and if the neurological symptoms are associated with the neurological insults in IG is still unclear.Methods: In the present study, we evaluated the UCO model in IG by analyzing neurological symptoms, neurological injury in the hippocampal CA1 region and compared with GG.Results: The data showed that the ratios of neurological symptom scores ≥ 2 in the IG and GG groups were 65.0% vs 30.0%, respectively, and were significantly different(P <.01).The neuronal damage following a UCO ischemic insult in the IG group was more severe compared to the GG group. There was a high correlation between the neurological insults' scale and the neurological symptom score in the IG and GG groups(r =.979 and.943 in the IG and GG groups, respectively). In animals with mild neurological symptom scores(2 and 3), the neuronal insults were significantly different between female and male gerbils in both IG and GG.Conclusion: Our findings suggest that IG population would likely be more advantageous to establish an ischemic model.
文摘An i-Line chemically amplified(ICA)thick film positive resist is reported in this paper.The impact of process conditions on photoresist performance was investigated.Pre-apply bake temperature and post exposure bake temperature affect acid diffusion and deblocking reactions,thus playing an integral role in defining the resist profile.Both pre-apply bake delay and post exposure delay(PED)affect critical dimension(CD)variation,but PED is more sensitive to contact with airborne contaminants.Different polymers and different photo-acid generators(PAG)are also illustrated in this work.By optimizing the structure and concentration of key components,an ICA resist with good environment stability and excellent lithographic performance was demonstrated.
基金This research was supported by National Natural Science Foundation of China(No.81873388)Shaanxi University of Traditional Chinese Medicine Meridian-Zang Fu Related Research Innovation Team Project(2019-YL09).
文摘Since it was put forward in 1995,musculo-dural bridge has been widely concerned.With the deepening of research,the structure,shape and physiological functions of musculo-dural bridge are gradually known.Previous studies have found that the musculo-dural bridge between muscle and dura mater can not only transfer proprioception,prevent the rupture of dura mater and ensure the normal flow of cerebrospinal fluid,but also be related to chronic cervicogenic headache.Therefore,this article mainly discusses the composition of musculo-dural bridge complex and its relationship with chronic cervicogenic headache,so as to provide a new diagnosis and treatment idea for the occurrence,development and treatment of related diseases in clinic.
基金the National Natu-ral Science Foundation of China(Nos.22108133,51972180,and 41907315)the Science,Education and Industry Integration of Basic Research Projects of Qilu University of Technology(No.2022PY062)the Youth Innovation Team Development Plan of Universities in Shandong Province(No.2021KJ056).
文摘S-scheme heterostructure photocatalysts utilize the synergistic and superposition effects of materials,ef-fectively separating electrons and holes,maintaining strong redox capacity,and addressing issues en-countered by current photocatalytic reactions.This review explores the origins and unique benefits of S-scheme heterojunctions.Specifically,we summarized and discussed the effects of different dimensions of semiconductors constituting S-scheme heterojunctions and the similarities and differences in elec-tron transfer processes when constructing heterojunctions.Additionally,we analyzed several methods for proving the formation of S-scheme heterojunctions and the electron transfer process,both directly and indirectly.Finally,we review the applications of S-scheme heterojunctions in various fields of photo-catalysis,including photocatalytic water splitting,pollution degradation,CO_(2) reduction and other related photocatalytic applications.Our hope is that this review will provide an essential reference for the devel-opment and application of S-scheme heterojunction photocatalysis.
基金National Key Research and Development Program of China,Grant/Award Number:2021YFF0702402National Natural Science Foundation of China,Grant/Award Number:32070531。
文摘Background:The Mongolian gerbil is an excellent laboratory animal for preparing the cerebral ischemia model due to its inherent deficiency in the circle of Willis.However,the low incidence and unpredictability of symptoms are caused by numerous complex variant types of the circle.Additionally,the lack of an evaluation system for the cer-ebral ischemia/reperfusion(I/R)model of gerbils has shackled the application of this model.Methods:We created a symptom-oriented principle and detailed neurobehavioral scoring criteria.At different time points of reperfusion,we analyzed the alteration in locomotion by rotarod test and grip force score,infarct volume by triphenyltetrazo-lium chloride(TTC)staining,neuron loss using Nissl staining,and histological charac-teristics using hematoxylin-eosin(H&E)straining.Results:With a successful model rate of 56%,32 of the 57 gerbils operated by our method harbored typical features of cerebral I/R injury,and the mortality rate in the male gerbils was significantly higher than that in the female gerbils.The suc-cessfully prepared I/R gerbils demonstrated a significant reduction in motility and grip strength at 1 day after reperfusion;formed obvious infarction;exhibited typi-cal pathological features,such as tissue edema,neuronal atrophy and death,and vacuolated structures;and were partially recovered with the extension of reperfu-sion time.Conclusion:This study developed a new method for the unilateral common carotid artery ligation I/R model of gerbil and established a standardized evaluation system for this model,which could provide a new cerebral I/R model of gerbils with more practical applications.
基金This work was supported by the National Natural Science Foundation of China(81673240,and U1705283)the Chinese National Major Scientific and Technological Special Project for“Significant New Drugs Development”(2018ZX09308010,2012ZX09101316)the Fujian Provincial Major Scientific and Technological Project(2015YZ0002)and Xiamen Innovax.
文摘A new HPV-16/18 bivalent vaccine expressed by the Escherichia coli has been proven to be efficacious in adult women.A randomized,immunogenicity noninferiority study of this candidate vaccine was conducted in December 2015 in China.Girls aged 9–14 years were randomized to receive 2 doses at months 0 and 6(n=301)or 3 doses at months 0,1 and 6(n=304).Girls aged 15–17 years(n=149)and women aged 18–26 years(n=225)received 3 doses.The objectives included noninferiority analysis of the IgG geometric mean concentration(GMC)ratio(95%CI,lower bound>0.5)to HPV-16 and HPV-18 at month 7 in girls compared with women.In the per-protocol set,the GMC ratio of IgG was noninferior for girls aged 9–17 years receiving 3 doses compared with women(1.76(95%CI,1.56,1.99)for HPV-16 and 1.93(95%CI,1.69,2.21)for HPV-18)and noninferior for girls aged 9–14 years receiving 2 doses compared with women(1.45(95%CI,1.25,1.62)for HPV-16 and 1.17(95%CI,1.02,1.33)for HPV-18).Noninferiority was also demonstrated for neutralizing antibodies.The immunogenicity of the HPV vaccine in girls receiving 3 or 2 doses was noninferior compared with that in young adult women.
