In recent years,skeleton-based action recognition has made great achievements in Computer Vision.A graph convolutional network(GCN)is effective for action recognition,modelling the human skeleton as a spatio-temporal ...In recent years,skeleton-based action recognition has made great achievements in Computer Vision.A graph convolutional network(GCN)is effective for action recognition,modelling the human skeleton as a spatio-temporal graph.Most GCNs define the graph topology by physical relations of the human joints.However,this predefined graph ignores the spatial relationship between non-adjacent joint pairs in special actions and the behavior dependence between joint pairs,resulting in a low recognition rate for specific actions with implicit correlation between joint pairs.In addition,existing methods ignore the trend correlation between adjacent frames within an action and context clues,leading to erroneous action recognition with similar poses.Therefore,this study proposes a learnable GCN based on behavior dependence,which considers implicit joint correlation by constructing a dynamic learnable graph with extraction of specific behavior dependence of joint pairs.By using the weight relationship between the joint pairs,an adaptive model is constructed.It also designs a self-attention module to obtain their inter-frame topological relationship for exploring the context of actions.Combining the shared topology and the multi-head self-attention map,the module obtains the context-based clue topology to update the dynamic graph convolution,achieving accurate recognition of different actions with similar poses.Detailed experiments on public datasets demonstrate that the proposed method achieves better results and realizes higher quality representation of actions under various evaluation protocols compared to state-of-the-art methods.展开更多
In this paper,we study systems of conservation laws in one space dimension.We prove that for classical solutions in Sobolev spaces H^(s),with s>3/2,the data-to-solution map is not uniformly continuous.Our results a...In this paper,we study systems of conservation laws in one space dimension.We prove that for classical solutions in Sobolev spaces H^(s),with s>3/2,the data-to-solution map is not uniformly continuous.Our results apply to all nonlinear scalar conservation laws and to nonlinear hyperbolic systems of two equations.展开更多
Based on the EAM potential, a molecular dynamics study on the tensile properties of ultrathin nickel nanowires in the (100〉 orientation with diameters of 3.94, 4.95 and 5.99 nm was presented at different temperature...Based on the EAM potential, a molecular dynamics study on the tensile properties of ultrathin nickel nanowires in the (100〉 orientation with diameters of 3.94, 4.95 and 5.99 nm was presented at different temperatures and strain rates. The temperature and strain rate dependences of tensile properties were investigated. The simulation results show that the elastic modulus and the yield strength are gradually decreasing with the increase of temperature, while with the increase of the strain rate, the stress--strain curves fluctuate more intensely and the ultrathin nickel nanowires rupture at one smaller and smaller strain. At an ideal temperature of 0.01 K, the yield strength of the nanowires drops rapidly with the increase of strain rate, and at other temperatures the strain rate has a little influence on the elastic modulus and the yield strength. Finally, the effects of size on the tensile properties of ultrathin nickel nanowires were briefly discussed.展开更多
Field dependence/independence in Language Acquisition are discussed by many language learners.In this article,we will mainly focus on talking about the cognitive style,including the concept of Field-dependence/indepen...Field dependence/independence in Language Acquisition are discussed by many language learners.In this article,we will mainly focus on talking about the cognitive style,including the concept of Field-dependence/independence,their character istics and differences and functions in language acquisition.展开更多
In the present paper,with the help of the resolvent operator and some analytic methods,the exact controllability and continuous dependence are investigated for a fractional neutral integro-differential equations with ...In the present paper,with the help of the resolvent operator and some analytic methods,the exact controllability and continuous dependence are investigated for a fractional neutral integro-differential equations with state-dependent delay.As an application,we also give one example to demonstrate our results.展开更多
Ecological patterns and processes in dune ecosystems have been a research focus in recent years, however the information on how dune stabilization influences the spatial scale dependence of plant diversity is still la...Ecological patterns and processes in dune ecosystems have been a research focus in recent years, however the information on how dune stabilization influences the spatial scale dependence of plant diversity is still lacking. In this study, we measured the plant species richness, soil properties and altitude across four spatial scales (1, 10, 100 and 1,000 m2) at three different dune stabilization stages (mobile dune, semi-fixed dune and fixed dune) in Horqin Sandy Land, Northern China. We also examined the relationships between plant species richness, community composition and environmental factors along the gradient of dune stabilization. Our results showed that plant species richness increased with the increase of spatial scales in each dune stabilization stage, as well as with the increase of dune stabilization degrees. Canonical correspondence analysis (CCA) showed that plant distribu- tions in the processes of dune stabilization were determined by the combined environmental gradient in relation to soil organic carbon (SOC), total nitrogen (TN), carbon/nitrogen (C/N), pH, electrical conductivity (EC), soil water content (SWC), fine sand (FS), very fine sand (VFS), silt and clay (SC), and altitude. Plant species richness was significantly and positively correlated to SOC and TN in mobile dune, and significantly and positively correlated to SOC, TN, C/N, VFS and SC in semi-fixed dune. However, no significant correlation between plant species richness and environmental factors was observed in fixed dune. In addition, plant species richness in different dune stabili- zation stages was also determined by the combined gradient of soil properties and altitude. These results suggest that plant species richness has obvious scale dependence along the gradient of dune stabilization. Soil resources depending on dune habitats and environmental gradients caused by dune stabilization are important factors to de- termine the scale dependence of species diversity in sand dune ecosystems.展开更多
This paper presents a copula technique to develop time-variant seismic fragility curves for corroded bridges at the system level and considers the realistic time-varying dependence among component seismic demands. Bas...This paper presents a copula technique to develop time-variant seismic fragility curves for corroded bridges at the system level and considers the realistic time-varying dependence among component seismic demands. Based on material deterioration mechanisms and incremental dynamic analysis, the time-evolving seismic demands of components were obtained in the form of marginal probability distributions. The time-varying dependences among bridge components were then captured with the best fitting copula function, which was selected from the commonly used copula classes by the empirical distribution based analysis method. The system time-variant fragility curves at different damage states were developed and the effects of time-varying dependences among components on the bridge system fragility were investigated. The results indicate the time-varying dependence among components significantly affects the time-variant fragility of the bridge system. The copula technique captures the nonlinear dependence among component seismic demands accurately and easily by separating the marginal distributions and the dependence among them.展开更多
The high rate of relapse among heroin users remains a significant public concern in China. In the present study, we utilized a Motivation-Skill-Desensitization-Mental Energy (MSDE) intervention and evaluated its effec...The high rate of relapse among heroin users remains a significant public concern in China. In the present study, we utilized a Motivation-Skill-Desensitization-Mental Energy (MSDE) intervention and evaluated its effects on abstinence and mental health. Eighty-nine male heroin users in a drug rehabilitation center were enrolled in the study. The participants in the MSDE intervention group (n=46) received MSDE intervention, which included motivational interviewing, coping skills training, eye movement desensitization and reprocessing, and mindfulness-based psychotherapy. The participants in the control group (h=43) received a series of lectures on skills training. A significant increase in Contemplation Ladder score (P<0.001) and decreases in scores on the Obsessive Compulsive Drug Use Scale (P<0.001), Beck Depression Inventory (P<0.001), and Aggression Questionnaire (P=O.O33) were found immediately after intervention. Compared to the control group, the MSDE intervention group reported significantly higher abstinence rates (P=0.027) and retention rates (P<0.001) at follow-up. Overall, the MSDE intervention, which uses a combined strategy for relapse prevention, could be a promising approach for preventing relapse among heroin users in China.展开更多
Smoking of tobacco products continues to be a major cause of worldwide health problems. Epidemiological studies have shown that tobacco smoking is the greatest risk factor for the development of pancreatic cancer. Smo...Smoking of tobacco products continues to be a major cause of worldwide health problems. Epidemiological studies have shown that tobacco smoking is the greatest risk factor for the development of pancreatic cancer. Smokers who are able to quit smoking can reduce their risk of pancreatic cancer by nearly 50% within two years, however, their risk of developing pancreatic cancer remains higher than that of non-smokers for 10 years. Nicotine is the major psychoactive substance in tobacco, and is responsible for tobacco dependence and addiction. Recent evidence suggests that individuals have genetically based differences in their ability to metabolize nicotine, as well as genetic differences in the psychological reward pathways that may influence individual response to smoking initiation, dependence, addiction and cessation. Numerous associations have been reported between smoking behavior and genetic polymorphisms in genes that are responsible for nicotine metabolism. In addition, polymorphisms in genes that encode neurotransmitters and transporters that function in psychological reward pathways have been implicated in differences in smoking behavior. However, there is a large degree of between-study variability that demonstrates the need for larger, well-controlled casecontrol studies to identify target genes and deduce mechanisms that account for the genetic basis of interindividual differences in smoking behavior. Understanding the genetic factors that increase susceptibility to tobacco addiction may result in more effective tobacco cessation programs which will, in turn, reduce the incidence of tobacco related disease, including pancreatic cancer.展开更多
The temperature dependences of forward voltage drop(VF) of the fast recovery diodes(FRDs) are remarkably influenced by different lifetime controlled treatments. In this paper the results of an experimental study a...The temperature dependences of forward voltage drop(VF) of the fast recovery diodes(FRDs) are remarkably influenced by different lifetime controlled treatments. In this paper the results of an experimental study are presented, which are the lifetime controls of platinum treatment, electron irradiation treatment, and the combined treatment of the above ones.Based on deep level transient spectroscopy(DLTS) measurements, a new level E6(EC-0.376 e V) is found in the combined lifetime treated(CLT) sample, which is different from the levels of the individual platinum and electron irradiation ones. Comparing the tested VFresults of CLT samples with the others, the level E6 is responsible for the degradation of temperature dependence of the forward voltage drop in the FRD.展开更多
The concentration dependence of the reduced viscosity of dilute polymer solution is interpreted in the light of a new concept of the self-association of polymer chains in dilute solution. The apparent self-association...The concentration dependence of the reduced viscosity of dilute polymer solution is interpreted in the light of a new concept of the self-association of polymer chains in dilute solution. The apparent self-association constant is defined as the molar association constant divided by the molar mass of individual polymer chain and is numerically interconvertible with the Huggins coefficient. The molar association constant is directly proportional to the effective hydrodynamic volume of the polymer chain in solution and is irrespective of the chain architecture. The effective hydrodynamic volume accounts for the non-spherical conformation of a short polymer chain in solution and is a product of a shape factor and hydrodynamic volume. The observed enhancement of Huggins coefficient for short chain and branched polymer is satisfactorily interpreted by the concept of self-association. The concept of self-association allows us to predict the existence of a boundary concentration C-s(dynamic contact concentration) which divides the dilute polymer solution into two regions.展开更多
The wavelength dependence of laser induced breakdown spectroscopy (LIBS) in the analysis of the carbon contents of coal was studied using 266 nm and 1064 nm laser radiations. Compared with the 1064 nm wavelength las...The wavelength dependence of laser induced breakdown spectroscopy (LIBS) in the analysis of the carbon contents of coal was studied using 266 nm and 1064 nm laser radiations. Compared with the 1064 nm wavelength laser ablation, the 266 nm wavelength laser ablation has less thermal effects, resulting in a better crater morphology on the coal pellets. Besides, the 266 nm wavelength laser ablation also provides better laser-sample coupling and less plasma shielding, resulting in a higher carbon line intensity and better signal reproducibility. The carbon contents in the bituminous coal samples have better linearity with the line intensities of atomic carbon measured by the 266 nm wavelength than those measured by the 1064 nm wavelength. The partial least square (PLS) model was established for the quantitative analysis of the carbon content in coal samples by LIBS. The results show that both of the 266 nm and 1064 nm wavelengths are capable of achieving good performance for the quantitative analysis of carbon content in coal using the PLS method.展开更多
Although opportunistic maintenance strategies are widely used for multi-component systems, all opportunistic mainte- nance strategies only consider economic dependence and do not take structural dependence into accoun...Although opportunistic maintenance strategies are widely used for multi-component systems, all opportunistic mainte- nance strategies only consider economic dependence and do not take structural dependence into account. An opportunistic main- tenance strategy is presented for a multi-component system that considers both structural dependence and economic dependence. The cost relation and time relation among components based on structural dependence are developed. The maintenance strategy for each component of a multi-component system involves one of five maintenance actions, namely, no-maintenance, a minimal maintenance action, an imperfect maintenance action, a perfect maintenance action, and a replacement action. The maintenance action is determined by the virtual age of the component, the life expectancy of the component, and the age threshold values. Monte Carlo simulation is designed to obtain the optimal oppor- tunistic maintenance strategy of the system over its lifetime. The simulation result reveals that the minimum maintenance cost with a strategy that considers structural dependence is less than that with a strategy that does not consider structural dependence. The availability with a strategy that considers structural dependence is greater than that with a strategy that does not consider structural dependence under the same conditions.展开更多
We investigated factors contributing to mobile phone dependence. To 139 medical students, we administered a self-reporting questionnaire designed to evaluate mobile phone dependence, health-related lifestyle, patterns...We investigated factors contributing to mobile phone dependence. To 139 medical students, we administered a self-reporting questionnaire designed to evaluate mobile phone dependence, health-related lifestyle, patterns of behavior, and depressive state. Multivariate logistic regression analysis revealed that scores for poor health-related lifestyle, Type A behavior pattern, and presence of depression are independently associated with degree of mobile phone dependency. These findings suggest that persons with an unhealthy lifestyle, Type A behavior traits, or depression might benefit from mobile phone use guidance.展开更多
In this work, temperature dependences of small-signal model parameters in the SiGe HBT HICUM model are presented. Electrical elements in the small-signal equivalent circuit are first extracted at each temperature, the...In this work, temperature dependences of small-signal model parameters in the SiGe HBT HICUM model are presented. Electrical elements in the small-signal equivalent circuit are first extracted at each temperature, then the temperature dependences are determined by the series of extracted temperature coefficients, based on the established temperature for- mulas for corresponding model parameters. The proposed method is validated by a 1x 0.2 x 16 μm2 SiGe HBT over a wide temperature range (from 218 K to 473 K), and good matching is obtained between the extracted and modeled resuits. Therefore, we believe that the proposed extraction flow of model parameter temperature dependence is reliable for characterizing the transistor performance and guiding the circuit design over a wide temperature range.展开更多
Osteocytes, the most abundant bone cells, form an interconnected network in the lacunar-canalicular pore system (LCS) buried within the mineralized matrix, which allows osteocytes to obtain nutrients from the blood ...Osteocytes, the most abundant bone cells, form an interconnected network in the lacunar-canalicular pore system (LCS) buried within the mineralized matrix, which allows osteocytes to obtain nutrients from the blood supply, sense external mechanical signals, and communicate among themselves and with other cells on bone surfaces. In this study, we examined key features of the LCS network including the topological parameter and the detailed structure of individual connections and their variations in cortical and cancellous compa~ tments, at different ages, and in two disease conditions with altered mechanosensing (perlecan deficiency and diabetes). LCS network showed both topological stability, in terms of conservation of connectivity among osteocyte lacunae (similar to the "nodes" in a computer network), and considerable variability the pericellular annular fluid gap surrounding lacunae and canaliculi (similar to the "bandwidth" of individual links in a computer network). Age, in the range of our study (15-32 weeks), affected only the pericellular fluid annulus in cortical bone but not in cancellous bone. Diabetes impacted the spacing of the lacunae, while the perlecan deficiency had a profound influence on the pericellular fluid annulus. The LCS network features play important roles in osteocyte signaling and regulation of bone growth and adaptation.展开更多
In view of the high complexity of the objective world, an economic dependence between subsystems(paired and unpaired) is proposed, and then the maintenance cost and time under different economic dependences are formul...In view of the high complexity of the objective world, an economic dependence between subsystems(paired and unpaired) is proposed, and then the maintenance cost and time under different economic dependences are formulated in a simple and consistent manner. Selective maintenance problem under economic dependence(EDSMP) is presented based on a series–parallel system in this paper. A case study shows that the system reliability is promoted to a certain extent, which can validate the validity of the EDSMP model. The influence of the ratio of set-up cost on system performance is mainly discussed under different economic dependences. Several existing improvements of classical exhaust algorithm are further modified to solve a large sized EDSMP rapidly. Experimental results illustrate that these improvements can reduce CPU time significantly.Furthermore the contribution of each improvement is defined here, and then their contributions are compared thoroughly.展开更多
We investigated factors contributing to Internet addiction in 105 Japanese medical students. The subjects were administered by a self-reporting questionnaire designed to evaluate demographic factors, Internet addictio...We investigated factors contributing to Internet addiction in 105 Japanese medical students. The subjects were administered by a self-reporting questionnaire designed to evaluate demographic factors, Internet addiction, loneliness, health-related lifestyle factors, depressive state, patterns of behavior, and mobile phone dependence. Results of multivariate logistic regression analysis indicated that loneliness and mobile phone dependence were positively related to degree of addiction. Our findings suggest that Internet addiction is associated with loneliness and mobile phone dependence in Japanese students.展开更多
To understand the anisotropy dependence of the damage evolution and material removal during the machining process of MgF_(2) single crystals,nanoscratch tests of MgF_(2) single crystals with different crystal planes a...To understand the anisotropy dependence of the damage evolution and material removal during the machining process of MgF_(2) single crystals,nanoscratch tests of MgF_(2) single crystals with different crystal planes and directions were systematically performed,and surface morphologies of the scratched grooves under different conditions were analyzed.The experimental results indicated that anisotropy considerably affected the damage evolution in the machining process of MgF_(2) single crystals.A stress field model induced by the scratch was developed by considering the anisotropy,which indicated that during the loading process,median cracks induced by the tensile stress initiated and propagated at the front of the indenter.Lateral cracks induced by tensile stress initiated and propagated on the subsurface during the unloading process.In addition,surface radial cracks induced by the tensile stress were easily generated during the unloading process.The stress change led to the deflection of the propagation direction of lateral cracks.Therefore,the lateral cracks propagated to the workpiece surface,resulting in brittle removal in the form of chunk chips.The plastic deformation parameter indicated that the more the slip systems were activated,the more easily the plastic deformation occurred.The cleavage fracture parameter indicated that the cracks propagated along the activated cleavage planes,and the brittle chunk removal was owing to the subsurface cleavage cracks propagating to the crystal surface.Under the same processing parameters,the scratch of the(001)crystal plane along the[100]crystal-orientation was found to be the most conducive to achieving plastic machining of MgF_(2) single crystals.The theoretical results agreed well with the experimental results,which will not only enhance the understanding of the anisotropy dependence of the damage evolution and removal process during the machining of MgF_(2) crystals,but also provide a theoretical foundation for achieving the high-efficiency and low-damage processing of anisotropic single crystals.展开更多
With the aim of simulating the harsh temperature condition of space, a thallium-activated cesium iodide crystal(CsI:Tl) detector readout with a PIN photodiode(CsI:Tl(PD)) and with a silicon photomultiplier(CsI:Tl(SiPM...With the aim of simulating the harsh temperature condition of space, a thallium-activated cesium iodide crystal(CsI:Tl) detector readout with a PIN photodiode(CsI:Tl(PD)) and with a silicon photomultiplier(CsI:Tl(SiPM)) is investigated over a temperature range from-40 to 40 ℃. With the increase in temperature, the output signal increases by ~ 24% with CsI:Tl(PD) and decreases by ~69% with CsI:Tl(SiPM). To reduce the effect of temperature in outer space, a method of bias voltage compensation is adopted for CsI:Tl(SiPM). Our study demonstrates that after correcting the temperature the variation in the analog-to-digital converter's amplitude is< 3%.展开更多
基金supported in part by the 2023 Key Supported Project of the 14th Five Year Plan for Education and Science in Hunan Province with No.ND230795.
文摘In recent years,skeleton-based action recognition has made great achievements in Computer Vision.A graph convolutional network(GCN)is effective for action recognition,modelling the human skeleton as a spatio-temporal graph.Most GCNs define the graph topology by physical relations of the human joints.However,this predefined graph ignores the spatial relationship between non-adjacent joint pairs in special actions and the behavior dependence between joint pairs,resulting in a low recognition rate for specific actions with implicit correlation between joint pairs.In addition,existing methods ignore the trend correlation between adjacent frames within an action and context clues,leading to erroneous action recognition with similar poses.Therefore,this study proposes a learnable GCN based on behavior dependence,which considers implicit joint correlation by constructing a dynamic learnable graph with extraction of specific behavior dependence of joint pairs.By using the weight relationship between the joint pairs,an adaptive model is constructed.It also designs a self-attention module to obtain their inter-frame topological relationship for exploring the context of actions.Combining the shared topology and the multi-head self-attention map,the module obtains the context-based clue topology to update the dynamic graph convolution,achieving accurate recognition of different actions with similar poses.Detailed experiments on public datasets demonstrate that the proposed method achieves better results and realizes higher quality representation of actions under various evaluation protocols compared to state-of-the-art methods.
文摘In this paper,we study systems of conservation laws in one space dimension.We prove that for classical solutions in Sobolev spaces H^(s),with s>3/2,the data-to-solution map is not uniformly continuous.Our results apply to all nonlinear scalar conservation laws and to nonlinear hyperbolic systems of two equations.
基金Project(51205302)supported by the National Natural Science Foundation of ChinaProject(2013JM7017)supported by the Natural Science Basic Research Plan in Shanxi Province of ChinaProject(K5051304006)supported by the Fundamental Research Funds for the Central Universities,China
文摘Based on the EAM potential, a molecular dynamics study on the tensile properties of ultrathin nickel nanowires in the (100〉 orientation with diameters of 3.94, 4.95 and 5.99 nm was presented at different temperatures and strain rates. The temperature and strain rate dependences of tensile properties were investigated. The simulation results show that the elastic modulus and the yield strength are gradually decreasing with the increase of temperature, while with the increase of the strain rate, the stress--strain curves fluctuate more intensely and the ultrathin nickel nanowires rupture at one smaller and smaller strain. At an ideal temperature of 0.01 K, the yield strength of the nanowires drops rapidly with the increase of strain rate, and at other temperatures the strain rate has a little influence on the elastic modulus and the yield strength. Finally, the effects of size on the tensile properties of ultrathin nickel nanowires were briefly discussed.
文摘Field dependence/independence in Language Acquisition are discussed by many language learners.In this article,we will mainly focus on talking about the cognitive style,including the concept of Field-dependence/independence,their character istics and differences and functions in language acquisition.
文摘In the present paper,with the help of the resolvent operator and some analytic methods,the exact controllability and continuous dependence are investigated for a fractional neutral integro-differential equations with state-dependent delay.As an application,we also give one example to demonstrate our results.
基金financially supported by the National Natural Science Foundation of China (41171414)the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-EW-QN313)+1 种基金the Chinese Academy of Sciences Visiting Professorships for Senior International Scientists (2011T2Z36)the Key Project of Scientific and Technical Supporting Programs (2011BAC07B02-09), and the National Basic Research Program of China (2009CB421303)
文摘Ecological patterns and processes in dune ecosystems have been a research focus in recent years, however the information on how dune stabilization influences the spatial scale dependence of plant diversity is still lacking. In this study, we measured the plant species richness, soil properties and altitude across four spatial scales (1, 10, 100 and 1,000 m2) at three different dune stabilization stages (mobile dune, semi-fixed dune and fixed dune) in Horqin Sandy Land, Northern China. We also examined the relationships between plant species richness, community composition and environmental factors along the gradient of dune stabilization. Our results showed that plant species richness increased with the increase of spatial scales in each dune stabilization stage, as well as with the increase of dune stabilization degrees. Canonical correspondence analysis (CCA) showed that plant distribu- tions in the processes of dune stabilization were determined by the combined environmental gradient in relation to soil organic carbon (SOC), total nitrogen (TN), carbon/nitrogen (C/N), pH, electrical conductivity (EC), soil water content (SWC), fine sand (FS), very fine sand (VFS), silt and clay (SC), and altitude. Plant species richness was significantly and positively correlated to SOC and TN in mobile dune, and significantly and positively correlated to SOC, TN, C/N, VFS and SC in semi-fixed dune. However, no significant correlation between plant species richness and environmental factors was observed in fixed dune. In addition, plant species richness in different dune stabili- zation stages was also determined by the combined gradient of soil properties and altitude. These results suggest that plant species richness has obvious scale dependence along the gradient of dune stabilization. Soil resources depending on dune habitats and environmental gradients caused by dune stabilization are important factors to de- termine the scale dependence of species diversity in sand dune ecosystems.
基金Natural Science Foundation of China under Grant No.51808376
文摘This paper presents a copula technique to develop time-variant seismic fragility curves for corroded bridges at the system level and considers the realistic time-varying dependence among component seismic demands. Based on material deterioration mechanisms and incremental dynamic analysis, the time-evolving seismic demands of components were obtained in the form of marginal probability distributions. The time-varying dependences among bridge components were then captured with the best fitting copula function, which was selected from the commonly used copula classes by the empirical distribution based analysis method. The system time-variant fragility curves at different damage states were developed and the effects of time-varying dependences among components on the bridge system fragility were investigated. The results indicate the time-varying dependence among components significantly affects the time-variant fragility of the bridge system. The copula technique captures the nonlinear dependence among component seismic demands accurately and easily by separating the marginal distributions and the dependence among them.
基金This study was funded by the National Natural Science Foundation of China (No.30872175,No.81573236).
文摘The high rate of relapse among heroin users remains a significant public concern in China. In the present study, we utilized a Motivation-Skill-Desensitization-Mental Energy (MSDE) intervention and evaluated its effects on abstinence and mental health. Eighty-nine male heroin users in a drug rehabilitation center were enrolled in the study. The participants in the MSDE intervention group (n=46) received MSDE intervention, which included motivational interviewing, coping skills training, eye movement desensitization and reprocessing, and mindfulness-based psychotherapy. The participants in the control group (h=43) received a series of lectures on skills training. A significant increase in Contemplation Ladder score (P<0.001) and decreases in scores on the Obsessive Compulsive Drug Use Scale (P<0.001), Beck Depression Inventory (P<0.001), and Aggression Questionnaire (P=O.O33) were found immediately after intervention. Compared to the control group, the MSDE intervention group reported significantly higher abstinence rates (P=0.027) and retention rates (P<0.001) at follow-up. Overall, the MSDE intervention, which uses a combined strategy for relapse prevention, could be a promising approach for preventing relapse among heroin users in China.
文摘Smoking of tobacco products continues to be a major cause of worldwide health problems. Epidemiological studies have shown that tobacco smoking is the greatest risk factor for the development of pancreatic cancer. Smokers who are able to quit smoking can reduce their risk of pancreatic cancer by nearly 50% within two years, however, their risk of developing pancreatic cancer remains higher than that of non-smokers for 10 years. Nicotine is the major psychoactive substance in tobacco, and is responsible for tobacco dependence and addiction. Recent evidence suggests that individuals have genetically based differences in their ability to metabolize nicotine, as well as genetic differences in the psychological reward pathways that may influence individual response to smoking initiation, dependence, addiction and cessation. Numerous associations have been reported between smoking behavior and genetic polymorphisms in genes that are responsible for nicotine metabolism. In addition, polymorphisms in genes that encode neurotransmitters and transporters that function in psychological reward pathways have been implicated in differences in smoking behavior. However, there is a large degree of between-study variability that demonstrates the need for larger, well-controlled casecontrol studies to identify target genes and deduce mechanisms that account for the genetic basis of interindividual differences in smoking behavior. Understanding the genetic factors that increase susceptibility to tobacco addiction may result in more effective tobacco cessation programs which will, in turn, reduce the incidence of tobacco related disease, including pancreatic cancer.
基金Project supported by the Doctoral Fund of Ministry of Education of China(Grant No.20111103120016)the State Grid Corporation of China Program of Science and Technology,China(Grant No.5455DW140003)
文摘The temperature dependences of forward voltage drop(VF) of the fast recovery diodes(FRDs) are remarkably influenced by different lifetime controlled treatments. In this paper the results of an experimental study are presented, which are the lifetime controls of platinum treatment, electron irradiation treatment, and the combined treatment of the above ones.Based on deep level transient spectroscopy(DLTS) measurements, a new level E6(EC-0.376 e V) is found in the combined lifetime treated(CLT) sample, which is different from the levels of the individual platinum and electron irradiation ones. Comparing the tested VFresults of CLT samples with the others, the level E6 is responsible for the degradation of temperature dependence of the forward voltage drop in the FRD.
基金This work was supported by the Chinese National Basic Research Project "Macromolecular Condensed State" and National Natural Science Foundation of China
文摘The concentration dependence of the reduced viscosity of dilute polymer solution is interpreted in the light of a new concept of the self-association of polymer chains in dilute solution. The apparent self-association constant is defined as the molar association constant divided by the molar mass of individual polymer chain and is numerically interconvertible with the Huggins coefficient. The molar association constant is directly proportional to the effective hydrodynamic volume of the polymer chain in solution and is irrespective of the chain architecture. The effective hydrodynamic volume accounts for the non-spherical conformation of a short polymer chain in solution and is a product of a shape factor and hydrodynamic volume. The observed enhancement of Huggins coefficient for short chain and branched polymer is satisfactorily interpreted by the concept of self-association. The concept of self-association allows us to predict the existence of a boundary concentration C-s(dynamic contact concentration) which divides the dilute polymer solution into two regions.
基金supported by National Natural Science Foundation of China(No.51276100)National Basic Research Program of China(973 Program)(No.2013CB228501)
文摘The wavelength dependence of laser induced breakdown spectroscopy (LIBS) in the analysis of the carbon contents of coal was studied using 266 nm and 1064 nm laser radiations. Compared with the 1064 nm wavelength laser ablation, the 266 nm wavelength laser ablation has less thermal effects, resulting in a better crater morphology on the coal pellets. Besides, the 266 nm wavelength laser ablation also provides better laser-sample coupling and less plasma shielding, resulting in a higher carbon line intensity and better signal reproducibility. The carbon contents in the bituminous coal samples have better linearity with the line intensities of atomic carbon measured by the 266 nm wavelength than those measured by the 1064 nm wavelength. The partial least square (PLS) model was established for the quantitative analysis of the carbon content in coal samples by LIBS. The results show that both of the 266 nm and 1064 nm wavelengths are capable of achieving good performance for the quantitative analysis of carbon content in coal using the PLS method.
基金supported by the Postdoctoral Science Foundation of China(20080431380)
文摘Although opportunistic maintenance strategies are widely used for multi-component systems, all opportunistic mainte- nance strategies only consider economic dependence and do not take structural dependence into account. An opportunistic main- tenance strategy is presented for a multi-component system that considers both structural dependence and economic dependence. The cost relation and time relation among components based on structural dependence are developed. The maintenance strategy for each component of a multi-component system involves one of five maintenance actions, namely, no-maintenance, a minimal maintenance action, an imperfect maintenance action, a perfect maintenance action, and a replacement action. The maintenance action is determined by the virtual age of the component, the life expectancy of the component, and the age threshold values. Monte Carlo simulation is designed to obtain the optimal oppor- tunistic maintenance strategy of the system over its lifetime. The simulation result reveals that the minimum maintenance cost with a strategy that considers structural dependence is less than that with a strategy that does not consider structural dependence. The availability with a strategy that considers structural dependence is greater than that with a strategy that does not consider structural dependence under the same conditions.
文摘We investigated factors contributing to mobile phone dependence. To 139 medical students, we administered a self-reporting questionnaire designed to evaluate mobile phone dependence, health-related lifestyle, patterns of behavior, and depressive state. Multivariate logistic regression analysis revealed that scores for poor health-related lifestyle, Type A behavior pattern, and presence of depression are independently associated with degree of mobile phone dependency. These findings suggest that persons with an unhealthy lifestyle, Type A behavior traits, or depression might benefit from mobile phone use guidance.
基金supported partially by the Important National Science&Technology Specific Projects,China(Grant No.2013ZX02503003)
文摘In this work, temperature dependences of small-signal model parameters in the SiGe HBT HICUM model are presented. Electrical elements in the small-signal equivalent circuit are first extracted at each temperature, then the temperature dependences are determined by the series of extracted temperature coefficients, based on the established temperature for- mulas for corresponding model parameters. The proposed method is validated by a 1x 0.2 x 16 μm2 SiGe HBT over a wide temperature range (from 218 K to 473 K), and good matching is obtained between the extracted and modeled resuits. Therefore, we believe that the proposed extraction flow of model parameter temperature dependence is reliable for characterizing the transistor performance and guiding the circuit design over a wide temperature range.
基金supported partially by funds from the NIH (RO1AR054385, P30GM103333)
文摘Osteocytes, the most abundant bone cells, form an interconnected network in the lacunar-canalicular pore system (LCS) buried within the mineralized matrix, which allows osteocytes to obtain nutrients from the blood supply, sense external mechanical signals, and communicate among themselves and with other cells on bone surfaces. In this study, we examined key features of the LCS network including the topological parameter and the detailed structure of individual connections and their variations in cortical and cancellous compa~ tments, at different ages, and in two disease conditions with altered mechanosensing (perlecan deficiency and diabetes). LCS network showed both topological stability, in terms of conservation of connectivity among osteocyte lacunae (similar to the "nodes" in a computer network), and considerable variability the pericellular annular fluid gap surrounding lacunae and canaliculi (similar to the "bandwidth" of individual links in a computer network). Age, in the range of our study (15-32 weeks), affected only the pericellular fluid annulus in cortical bone but not in cancellous bone. Diabetes impacted the spacing of the lacunae, while the perlecan deficiency had a profound influence on the pericellular fluid annulus. The LCS network features play important roles in osteocyte signaling and regulation of bone growth and adaptation.
基金supported by the National Science Foundation of China (Grant No. 61305083)
文摘In view of the high complexity of the objective world, an economic dependence between subsystems(paired and unpaired) is proposed, and then the maintenance cost and time under different economic dependences are formulated in a simple and consistent manner. Selective maintenance problem under economic dependence(EDSMP) is presented based on a series–parallel system in this paper. A case study shows that the system reliability is promoted to a certain extent, which can validate the validity of the EDSMP model. The influence of the ratio of set-up cost on system performance is mainly discussed under different economic dependences. Several existing improvements of classical exhaust algorithm are further modified to solve a large sized EDSMP rapidly. Experimental results illustrate that these improvements can reduce CPU time significantly.Furthermore the contribution of each improvement is defined here, and then their contributions are compared thoroughly.
文摘We investigated factors contributing to Internet addiction in 105 Japanese medical students. The subjects were administered by a self-reporting questionnaire designed to evaluate demographic factors, Internet addiction, loneliness, health-related lifestyle factors, depressive state, patterns of behavior, and mobile phone dependence. Results of multivariate logistic regression analysis indicated that loneliness and mobile phone dependence were positively related to degree of addiction. Our findings suggest that Internet addiction is associated with loneliness and mobile phone dependence in Japanese students.
基金supported by the National Natural Science Foundation of China (52005134&51975154)China Postdoctoral Science Foundation (2022T150163, 2020M670901)+4 种基金Self-Planned Task (No. SKLRS202214B) of State Key Laboratory of Robotics and System (HIT)Heilongjiang Postdoctoral Fund (LBH-Z20016)Shenzhen Science and Technology Program (GJHZ20210705142804012)Fundamental Research Funds for the Central Universities(FRFCU5710051122)Open Fund of ZJUT Xinchang Research Institute
文摘To understand the anisotropy dependence of the damage evolution and material removal during the machining process of MgF_(2) single crystals,nanoscratch tests of MgF_(2) single crystals with different crystal planes and directions were systematically performed,and surface morphologies of the scratched grooves under different conditions were analyzed.The experimental results indicated that anisotropy considerably affected the damage evolution in the machining process of MgF_(2) single crystals.A stress field model induced by the scratch was developed by considering the anisotropy,which indicated that during the loading process,median cracks induced by the tensile stress initiated and propagated at the front of the indenter.Lateral cracks induced by tensile stress initiated and propagated on the subsurface during the unloading process.In addition,surface radial cracks induced by the tensile stress were easily generated during the unloading process.The stress change led to the deflection of the propagation direction of lateral cracks.Therefore,the lateral cracks propagated to the workpiece surface,resulting in brittle removal in the form of chunk chips.The plastic deformation parameter indicated that the more the slip systems were activated,the more easily the plastic deformation occurred.The cleavage fracture parameter indicated that the cracks propagated along the activated cleavage planes,and the brittle chunk removal was owing to the subsurface cleavage cracks propagating to the crystal surface.Under the same processing parameters,the scratch of the(001)crystal plane along the[100]crystal-orientation was found to be the most conducive to achieving plastic machining of MgF_(2) single crystals.The theoretical results agreed well with the experimental results,which will not only enhance the understanding of the anisotropy dependence of the damage evolution and removal process during the machining of MgF_(2) crystals,but also provide a theoretical foundation for achieving the high-efficiency and low-damage processing of anisotropic single crystals.
基金supported by the National Natural Science Foundation of China(Nos.11575257,11575269,and U1732134)the Youth Innovation Promotion Association of the Chinese Academy of Science(No.2015342)
文摘With the aim of simulating the harsh temperature condition of space, a thallium-activated cesium iodide crystal(CsI:Tl) detector readout with a PIN photodiode(CsI:Tl(PD)) and with a silicon photomultiplier(CsI:Tl(SiPM)) is investigated over a temperature range from-40 to 40 ℃. With the increase in temperature, the output signal increases by ~ 24% with CsI:Tl(PD) and decreases by ~69% with CsI:Tl(SiPM). To reduce the effect of temperature in outer space, a method of bias voltage compensation is adopted for CsI:Tl(SiPM). Our study demonstrates that after correcting the temperature the variation in the analog-to-digital converter's amplitude is< 3%.