The failure of slope caused by variations in water levels on both banks of reservoirs is common.Reservoir landslides greatly threaten the safety of reservoir area.Taking large-scale composite deposits located on the L...The failure of slope caused by variations in water levels on both banks of reservoirs is common.Reservoir landslides greatly threaten the safety of reservoir area.Taking large-scale composite deposits located on the Lancang River in Southwest China as a study case,the origin of the deposits was analyzed based on the field investigation and a multi-material model was established in the physical model test.Combined with numerical simulation,the failure mechanism of the composite deposits during reservoir water level variations was studied.The results indicate that the deformation of the large-scale composite deposits is a staged sliding mode during the impoundment process.The first slip deformation is greatly affected by the buoyancy weight-reducing effect,and the permeability of soil and variation in the water level are the factors controlling slope deformation initiation.The high water sensitivity and low permeability of fine grained soil play an important role in the re-deformation of deposits slope.During the impoundment process,the deformation trend of the deposit slope is decreasing,and vertical consolidation of soil and increasing hydrostatic pressure on the slope surface are the main reasons for deformation attenuation.It is considered that the probability of large-scale sliding of the deposits during the impoundment period is low.But the damage caused by local bank collapse of the deposit slope still needs attention.The results of this paper will further improve our understanding of the failure mechanism of composite deposits caused by water level increases and provide guidance for the construction of hydropower stations.展开更多
Allocation is one of main tasks in the high-level synthesis. It includes module , functional unit allocation, storage allocation and interconnection allocation. This paper models the allocation problem as cluster anal...Allocation is one of main tasks in the high-level synthesis. It includes module , functional unit allocation, storage allocation and interconnection allocation. This paper models the allocation problem as cluster analysis and applies a new algorithm, neighbor state transition (NST) algorithm, for cluster optimization. It is proved that the algorithm produces an asymptotically global optimal solution with the upper bound on the cost function (1 + O(1/n)2-ε)F*, When F" is the cost of the optimum solution, n is the problem size and e is a positive parameter arbitrarily close to zero. The numerical examples show that the NST algorithm produces better results compared to the other known methods.展开更多
Owing to their excellent performance and large design space,curvilinear fiber-reinforced composite structures have gained considerable attention in engineering fields such as aerospace and automobile.In addition to th...Owing to their excellent performance and large design space,curvilinear fiber-reinforced composite structures have gained considerable attention in engineering fields such as aerospace and automobile.In addition to the stiffness and strength of such structures,their stability also needs to be taken into account in the design.This study proposes a level-set-based optimization framework for maximizing the buckling load of curvilinear fiber-reinforced composite structures.In the proposed method,the contours of the level set function are used to represent fiber paths.For a composite laminate with a certain number of layers,one level set function is defined by radial basis functions and expansion coefficients for each layer.Furthermore,the fiber angle at an arbitrary point is the tangent orientation of the contour through this point.In the finite element of buckling,the stiffness and geometry matrices of an element are related to the fiber angle at the element centroid.This study considers the parallelism constraint for fiber paths.With the sensitivity calculation of the objective and constraint functions,the method of moving asymptotes is utilized to iteratively update all the expansion coefficients regarded as design variables.Two numerical examples under different boundary conditions are given to validate the proposed approach.Results show that the optimized curved fiber paths tend to be parallel and equidistant regardless of whether the composite laminates contain holes or not.Meanwhile,the buckling resistance of the final design is significantly improved.展开更多
This paper describes an experimental study of the hysteretic behavior of prestressed truss concrete composite beams (PTCCBs) under cyclic loading. Five beam models were designed and tested, in which the testing para...This paper describes an experimental study of the hysteretic behavior of prestressed truss concrete composite beams (PTCCBs) under cyclic loading. Five beam models were designed and tested, in which the testing parameters include the global reinforcement index β0, the prestress level 2 and the ratio of stirrup ρsv in the potential plastic hinge zones. Based on the test results, the failure mode and hysteretic behavior of the tested models are obtained. In addition, the P-△ and sectional M-φ hysteretic models for the PTCCBs at the midspan are established. The P-△ hysteretic model shows good agreement with the test results.展开更多
Steel-concrete composite structures that share the advantages of both steel structure and concrete structure have been developed rapidly and used widely. It has been a popular structure in high-rise buildings in recen...Steel-concrete composite structures that share the advantages of both steel structure and concrete structure have been developed rapidly and used widely. It has been a popular structure in high-rise buildings in recent years. Although more and more composite structures have been used in earthquake area, only a few literatures about fragility analysis of this type of structure are available. In this paper, a fragility analysis method based on performance is proposed, in which both the uncertainty due to variability in structures and ground motion are considered. Seismic fragility analysis is performed for a 15-story composite beam-concrete-filled square steel tube column frame by the proposed method. The top-drift-angle and the story-drift-angle are used as quantitative indexes to define the four different performance levels. Then seismic demand probability analysis is carried out and fragility curves are derived to assess the seismic performance of this type of structure.展开更多
The objective of the study was to investigate the effects of dietary energy levels and sources on the blood metabolites,hormone secretion and the composition of follicular fluid in gilts.Fifty-four gilts with initial ...The objective of the study was to investigate the effects of dietary energy levels and sources on the blood metabolites,hormone secretion and the composition of follicular fluid in gilts.Fifty-four gilts with initial body weight of(59±4.2) kg were randomly allotted to six treatments.Treatments were low, normal,and high energy feeding levels,which were 87.5%,100%and 112.5%of recommendatory energy requirements by NRC(1998),respectively,and dietary energy sources(starch or fat).Blood samples and follicular fluids were collected on D18 and D19 of the second estrous cycle.The results showed that plasma concentrations of triglycerides and total cholesterol were higher in the fat group than that in the starch group(P【0.05),but those of glucose were similar between the two energy sources(P】0.05);dietary energy level exerted no effect on blood metabolites concentration(P】0.05).Gilts fed the high energy diet had a higher area under curve of plasma insulin(Insulin AUC),insulin-like growth factor-Ⅰ(IGF-Ⅰ) and leptin than did gilts fed the lower energy diet(P【0.05),but there was no significant difference between fat versus starch(P】0.05).Luteinizing hormone(LH) pulses were higher in gilts fed high energy rather than that in low energy diets(P】0.05),plasma concentration of estradiol(E<sub>2</sub>) was higher in the fat group than that in the starch group(P【0.05).The number of large follicles(diameter≥4 mm) and concentrations of IGF-Ⅰand E<sub>2</sub> in follicular fluid were increasing significant as the level of energy increased(P【0.05),but the numbers of large follicles and follicular fluid composition were not affected by the source of dietary energy(P】0.05).The results indicate that gilts fed high energy diets had elevated plasma concentrations of metabolic hormones,IGF-Ⅰand LH secretion,and increased follicular fluid concentrations of IGF-Ⅰ,E<sub>2</sub> and numbers of large follicles;gilts fed the dietary fat had a higher plasma concentration of cholesterol and E<sub>2</sub>.展开更多
Energy efficiency(EE)of downlink distributed antenna system(DAS)with multiple receive antennas is investigated over composite Rayleigh fading channel that takes the path loss and lognormal shadow fading into account.O...Energy efficiency(EE)of downlink distributed antenna system(DAS)with multiple receive antennas is investigated over composite Rayleigh fading channel that takes the path loss and lognormal shadow fading into account.Our aim is to maximize EE which is defined as the ratio of the transmission rate to the total consumed power under the constraints of the maximum transmit power of each remote antenna.According to the definition of EE,the optimized objective function is formulated with the help of Lagrangian method.By using the Karush-KuhnTucker(KKT)conditions and numerical calculation,considering both the static and dynamic circuit power consumptions,an adaptive energy efficient power allocation(PA)scheme is derived.This scheme is different from the conventional iterative PA schemes based on EE maximization since it can provide closed-form expression of PA coefficients.Moreover,it can obtain the EE performance close to the conventional iterative scheme and exhaustive search method while reducing the computation complexity greatly.Simulation results verify the effectiveness of the proposed scheme.展开更多
Obesity, particularly abdominal obesity, increases the risk of cardiovascular disease (CVD). This study investigates the effects of six-week (twice a week, 12 sessions total) extracorporeal shockwave therapy (SWT) and...Obesity, particularly abdominal obesity, increases the risk of cardiovascular disease (CVD). This study investigates the effects of six-week (twice a week, 12 sessions total) extracorporeal shockwave therapy (SWT) and hand massage therapy (HT) on body composition and serum lipids in overweight and obese Korean women aged between 35 and 59, according to their serum cholesterol level (≥200 mg/dL versus <200 mg/dL). After the program, weights decreased significantly in both the HT Group and SWT Group (p < 0.05);weights of those with cholesterol < 200 mg/dL significantly decreased in the HT Group (p = 0.038), while weights of those with cholesterol ≥ 200 mg/dL significantly decreased in the SWT Group (p = 0.001). BMIs decreased significantly in both the HT Group and the SWT Group (p < 0.05);BMIs of those with cholesterol < 200 mg/dL significantly decreased in the HT Group (p = 0.018), while BMIs of those with cholesterol ≥ 200 mg/dL significantly decreased in the SWT Group (p = 0.001). The body fat percentage of subjects significantly decreased only in the SWT Group (p = 0.027);the waist-hip ratio significantly decreased only in HT Group (p = 0.034). Serum cholesterol levels significantly decreased in those with cholesterol < 200 mg/dL in the HT Group (p < 0.05) and those with cholesterol ≥ 200 mg/dL in SWT Group (p = 0.055). Triglyceride significantly decreased in both those with cholesterol < 200 mg/dL and those with cholesterol ≥ 200 mg/dL, but did not significantly decrease in either subgroup of the HT Group. The study results suggest that SWT is effective in improving body measurements and serum lipids in those with cholesterol ≥ 200 mg/dL, while HT therapy is effective in those with cholesterol < 200 mg/dL. In conclusion, SWT and HT improved abdominal obesity by reducing body weight and waist circumference and helped improving serum lip index, suggesting the benefit for managing body measurements and serum lipids of overweight and obese individuals.展开更多
Spectrum access approach and power allocation scheme are important techniques in cognitive radio(CR) system,which not only affect communication performance of CR user(secondary user,SU) but also play decisive role for...Spectrum access approach and power allocation scheme are important techniques in cognitive radio(CR) system,which not only affect communication performance of CR user(secondary user,SU) but also play decisive role for protection of primary user(PU).In this study,we propose a power allocation scheme for SU based on the status sensing of PU in a single-input single-output(SISO) CR network.Instead of the conventional binary primary transmit power strategy,namely the sensed PU has only present or absent status,we consider a more practical scenario when PU transmits with multiple levels of power and quantized side information known by SU in advance as a primary quantized codebook.The secondary power allocation scheme to maximize the average throughput under the rate loss constraint(RLC) of PU is parameterized by the sensing results for PU,the primary quantized codebook and the channel state information(CSI) of SU.Furthermore,Differential Evolution(DE) algorithm is used to solve this non-convex power allocation problem.Simulation results show the performance and effectiveness of our proposed scheme under more practical communication conditions.展开更多
基金financed by the National Natural Science Foundation of China(Grant Nos.41472274,41672300)Independent Subject Foundation of SKLGP(SKLGP2017Z010)。
文摘The failure of slope caused by variations in water levels on both banks of reservoirs is common.Reservoir landslides greatly threaten the safety of reservoir area.Taking large-scale composite deposits located on the Lancang River in Southwest China as a study case,the origin of the deposits was analyzed based on the field investigation and a multi-material model was established in the physical model test.Combined with numerical simulation,the failure mechanism of the composite deposits during reservoir water level variations was studied.The results indicate that the deformation of the large-scale composite deposits is a staged sliding mode during the impoundment process.The first slip deformation is greatly affected by the buoyancy weight-reducing effect,and the permeability of soil and variation in the water level are the factors controlling slope deformation initiation.The high water sensitivity and low permeability of fine grained soil play an important role in the re-deformation of deposits slope.During the impoundment process,the deformation trend of the deposit slope is decreasing,and vertical consolidation of soil and increasing hydrostatic pressure on the slope surface are the main reasons for deformation attenuation.It is considered that the probability of large-scale sliding of the deposits during the impoundment period is low.But the damage caused by local bank collapse of the deposit slope still needs attention.The results of this paper will further improve our understanding of the failure mechanism of composite deposits caused by water level increases and provide guidance for the construction of hydropower stations.
文摘Allocation is one of main tasks in the high-level synthesis. It includes module , functional unit allocation, storage allocation and interconnection allocation. This paper models the allocation problem as cluster analysis and applies a new algorithm, neighbor state transition (NST) algorithm, for cluster optimization. It is proved that the algorithm produces an asymptotically global optimal solution with the upper bound on the cost function (1 + O(1/n)2-ε)F*, When F" is the cost of the optimum solution, n is the problem size and e is a positive parameter arbitrarily close to zero. The numerical examples show that the NST algorithm produces better results compared to the other known methods.
基金supported by the National Natural Science Foundation of China(Grant Nos.51975227 and 12272144)。
文摘Owing to their excellent performance and large design space,curvilinear fiber-reinforced composite structures have gained considerable attention in engineering fields such as aerospace and automobile.In addition to the stiffness and strength of such structures,their stability also needs to be taken into account in the design.This study proposes a level-set-based optimization framework for maximizing the buckling load of curvilinear fiber-reinforced composite structures.In the proposed method,the contours of the level set function are used to represent fiber paths.For a composite laminate with a certain number of layers,one level set function is defined by radial basis functions and expansion coefficients for each layer.Furthermore,the fiber angle at an arbitrary point is the tangent orientation of the contour through this point.In the finite element of buckling,the stiffness and geometry matrices of an element are related to the fiber angle at the element centroid.This study considers the parallelism constraint for fiber paths.With the sensitivity calculation of the objective and constraint functions,the method of moving asymptotes is utilized to iteratively update all the expansion coefficients regarded as design variables.Two numerical examples under different boundary conditions are given to validate the proposed approach.Results show that the optimized curved fiber paths tend to be parallel and equidistant regardless of whether the composite laminates contain holes or not.Meanwhile,the buckling resistance of the final design is significantly improved.
基金National Science and Technology Support Program Subtopics Under Grant No.2006BAJ03A10-07Changjiang Scholars Program of China
文摘This paper describes an experimental study of the hysteretic behavior of prestressed truss concrete composite beams (PTCCBs) under cyclic loading. Five beam models were designed and tested, in which the testing parameters include the global reinforcement index β0, the prestress level 2 and the ratio of stirrup ρsv in the potential plastic hinge zones. Based on the test results, the failure mode and hysteretic behavior of the tested models are obtained. In addition, the P-△ and sectional M-φ hysteretic models for the PTCCBs at the midspan are established. The P-△ hysteretic model shows good agreement with the test results.
文摘Steel-concrete composite structures that share the advantages of both steel structure and concrete structure have been developed rapidly and used widely. It has been a popular structure in high-rise buildings in recent years. Although more and more composite structures have been used in earthquake area, only a few literatures about fragility analysis of this type of structure are available. In this paper, a fragility analysis method based on performance is proposed, in which both the uncertainty due to variability in structures and ground motion are considered. Seismic fragility analysis is performed for a 15-story composite beam-concrete-filled square steel tube column frame by the proposed method. The top-drift-angle and the story-drift-angle are used as quantitative indexes to define the four different performance levels. Then seismic demand probability analysis is carried out and fragility curves are derived to assess the seismic performance of this type of structure.
基金supported by Program for Changjiang Scholars and Innovative Research Team in University (IRT0555)National Natural Science Foundation (30471257) of China
文摘The objective of the study was to investigate the effects of dietary energy levels and sources on the blood metabolites,hormone secretion and the composition of follicular fluid in gilts.Fifty-four gilts with initial body weight of(59±4.2) kg were randomly allotted to six treatments.Treatments were low, normal,and high energy feeding levels,which were 87.5%,100%and 112.5%of recommendatory energy requirements by NRC(1998),respectively,and dietary energy sources(starch or fat).Blood samples and follicular fluids were collected on D18 and D19 of the second estrous cycle.The results showed that plasma concentrations of triglycerides and total cholesterol were higher in the fat group than that in the starch group(P【0.05),but those of glucose were similar between the two energy sources(P】0.05);dietary energy level exerted no effect on blood metabolites concentration(P】0.05).Gilts fed the high energy diet had a higher area under curve of plasma insulin(Insulin AUC),insulin-like growth factor-Ⅰ(IGF-Ⅰ) and leptin than did gilts fed the lower energy diet(P【0.05),but there was no significant difference between fat versus starch(P】0.05).Luteinizing hormone(LH) pulses were higher in gilts fed high energy rather than that in low energy diets(P】0.05),plasma concentration of estradiol(E<sub>2</sub>) was higher in the fat group than that in the starch group(P【0.05).The number of large follicles(diameter≥4 mm) and concentrations of IGF-Ⅰand E<sub>2</sub> in follicular fluid were increasing significant as the level of energy increased(P【0.05),but the numbers of large follicles and follicular fluid composition were not affected by the source of dietary energy(P】0.05).The results indicate that gilts fed high energy diets had elevated plasma concentrations of metabolic hormones,IGF-Ⅰand LH secretion,and increased follicular fluid concentrations of IGF-Ⅰ,E<sub>2</sub> and numbers of large follicles;gilts fed the dietary fat had a higher plasma concentration of cholesterol and E<sub>2</sub>.
基金supported by the National Natural Science Foundation of China(Nos.61571225,61571224)the Fundamental Research Funds for the Central Universities+2 种基金the Research Founding of Graduate Innovation Center in NUAA (No.kfjj20160409)the Qing Lan Project of Jiangsu,Shenzhen Strategic Emerging Industry Development Funds(No.JSGG20150331160845693)the Six Talent Peaks Project in Jiangsu Province(No.DZXX-007)
文摘Energy efficiency(EE)of downlink distributed antenna system(DAS)with multiple receive antennas is investigated over composite Rayleigh fading channel that takes the path loss and lognormal shadow fading into account.Our aim is to maximize EE which is defined as the ratio of the transmission rate to the total consumed power under the constraints of the maximum transmit power of each remote antenna.According to the definition of EE,the optimized objective function is formulated with the help of Lagrangian method.By using the Karush-KuhnTucker(KKT)conditions and numerical calculation,considering both the static and dynamic circuit power consumptions,an adaptive energy efficient power allocation(PA)scheme is derived.This scheme is different from the conventional iterative PA schemes based on EE maximization since it can provide closed-form expression of PA coefficients.Moreover,it can obtain the EE performance close to the conventional iterative scheme and exhaustive search method while reducing the computation complexity greatly.Simulation results verify the effectiveness of the proposed scheme.
文摘Obesity, particularly abdominal obesity, increases the risk of cardiovascular disease (CVD). This study investigates the effects of six-week (twice a week, 12 sessions total) extracorporeal shockwave therapy (SWT) and hand massage therapy (HT) on body composition and serum lipids in overweight and obese Korean women aged between 35 and 59, according to their serum cholesterol level (≥200 mg/dL versus <200 mg/dL). After the program, weights decreased significantly in both the HT Group and SWT Group (p < 0.05);weights of those with cholesterol < 200 mg/dL significantly decreased in the HT Group (p = 0.038), while weights of those with cholesterol ≥ 200 mg/dL significantly decreased in the SWT Group (p = 0.001). BMIs decreased significantly in both the HT Group and the SWT Group (p < 0.05);BMIs of those with cholesterol < 200 mg/dL significantly decreased in the HT Group (p = 0.018), while BMIs of those with cholesterol ≥ 200 mg/dL significantly decreased in the SWT Group (p = 0.001). The body fat percentage of subjects significantly decreased only in the SWT Group (p = 0.027);the waist-hip ratio significantly decreased only in HT Group (p = 0.034). Serum cholesterol levels significantly decreased in those with cholesterol < 200 mg/dL in the HT Group (p < 0.05) and those with cholesterol ≥ 200 mg/dL in SWT Group (p = 0.055). Triglyceride significantly decreased in both those with cholesterol < 200 mg/dL and those with cholesterol ≥ 200 mg/dL, but did not significantly decrease in either subgroup of the HT Group. The study results suggest that SWT is effective in improving body measurements and serum lipids in those with cholesterol ≥ 200 mg/dL, while HT therapy is effective in those with cholesterol < 200 mg/dL. In conclusion, SWT and HT improved abdominal obesity by reducing body weight and waist circumference and helped improving serum lip index, suggesting the benefit for managing body measurements and serum lipids of overweight and obese individuals.
基金supported by the National Natural Science Foundation of China(Grant No.61571209)
文摘Spectrum access approach and power allocation scheme are important techniques in cognitive radio(CR) system,which not only affect communication performance of CR user(secondary user,SU) but also play decisive role for protection of primary user(PU).In this study,we propose a power allocation scheme for SU based on the status sensing of PU in a single-input single-output(SISO) CR network.Instead of the conventional binary primary transmit power strategy,namely the sensed PU has only present or absent status,we consider a more practical scenario when PU transmits with multiple levels of power and quantized side information known by SU in advance as a primary quantized codebook.The secondary power allocation scheme to maximize the average throughput under the rate loss constraint(RLC) of PU is parameterized by the sensing results for PU,the primary quantized codebook and the channel state information(CSI) of SU.Furthermore,Differential Evolution(DE) algorithm is used to solve this non-convex power allocation problem.Simulation results show the performance and effectiveness of our proposed scheme under more practical communication conditions.