The hidden world of amyloid biology has suddenly snapped into atomic-level focus,revealing over 80 amyloid protein fibrils,both pathogenic and functional.Unlike globular proteins,amyloid proteins flatten and stack int...The hidden world of amyloid biology has suddenly snapped into atomic-level focus,revealing over 80 amyloid protein fibrils,both pathogenic and functional.Unlike globular proteins,amyloid proteins flatten and stack into unbranched fibrils.Stranger still,a single protein sequence can adopt wildly different two-dimensional conformations,yielding distinct fibril polymorphs.展开更多
On January 3,2023,China welcomed the first visit in the new year by a foreign head of state,Philippine President Ferdinand Marcos Jr.The visit was also the president’s first official state visit to a country outside ...On January 3,2023,China welcomed the first visit in the new year by a foreign head of state,Philippine President Ferdinand Marcos Jr.The visit was also the president’s first official state visit to a country outside ASEAN since he took office in June 2022,which demonstrated the great importance the two countries attach to their bilateral relations.The three-day visit was fruitful despite a tight schedule.展开更多
China and FAO assist Uganda to become self-sufficent in food production, and serve as the food basket of the region Eighty percent of Uganda’s economy depends on agriculture, according to the Uganda Bureau of Statist...China and FAO assist Uganda to become self-sufficent in food production, and serve as the food basket of the region Eighty percent of Uganda’s economy depends on agriculture, according to the Uganda Bureau of Statistics. For this reason, Frank Tumwebaze, Uganda’s minister of agriculture, animal industry and fisheries, said in an interview recently that since the majority of the country’s population is involved in agriculture.展开更多
For the characterization of the behaviors of a metal material in events like expanding warheads, it is necessary to know its strength and ductility at high strain rates, around 104e105/s. The flyer plate impact testin...For the characterization of the behaviors of a metal material in events like expanding warheads, it is necessary to know its strength and ductility at high strain rates, around 104e105/s. The flyer plate impact testing produces the uniform stress and strain rates but the testing is expensive. The Taylor test is relatively inexpensive but produces non-uniform stress and strain fields, and the results are not so easily inferred for material modeling. In the split-Hopkinson bar(SHB), which may be used in compression, tension and torsion testing, the strain rates never exceeds 103/s. In the present work, we use the expanding ring test where the strain rate is 104e105/s. A streak camera is used to examine the expanding ring velocity, and a water tank is used to collect the fragments. The experimental results are compared with the numerical simulations using the hydrocodes AUTODYN, IMPETUS Afea and a regularized smooth particle(RSPH) software. The number of fragments increases with the increase in the expansion velocity of the rings. The number of fragments is similar to the experimental results. The RSPH software shows much the same results as the AUTODYN where the Lagrangian solver is used for the ring. The IMPETUS Afea solver shows a somewhat different fragmentation characteristic due to the node splitting algorithm that induces pronounced tensile splitting.展开更多
Exotic invaders may possess novel biochemical weapons that native plants do not have, and these novel biochemical weapons may be more allelopathic than those from native plants to other native competitors. During rang...Exotic invaders may possess novel biochemical weapons that native plants do not have, and these novel biochemical weapons may be more allelopathic than those from native plants to other native competitors. During range expansion, native species also encounter many new plant competitors. Thus, allelochemicals from native expanding species may also be more novel and allelopathic than those from non-expanding species to other plant competitors in the expanded range. We test this hypothesis using the native expanding Merremia boisiana and its non-expanding congener M. vitifolia in year 2012 inthe expanded range inHainan. In petridish bioassays, we found that aqueous extracts of M. boisiana leaves were often less inhibitory or more stimulatory to seed germination and seedling growth of five vegetable species than those of M. vitifolia leaves. In pot culture, we also found that aqueous leaf extracts of the two congeners could both inhibit the growth of a naturally co-occurring plant Paederia scanden, but their effects did not differ from each other. These results indicate that while allelopathy may contribute to the competitive ability of M. boisiana, it may not act as a novel weapon explaining its success in the expanded range in Hainan.展开更多
BACKGROUND Self-expanding metal stents are the main palliative treatment modality for unresectable esophageal cancer. Gastroesophageal reflux is a common adverse outcome after placement of esophageal stent for cancer ...BACKGROUND Self-expanding metal stents are the main palliative treatment modality for unresectable esophageal cancer. Gastroesophageal reflux is a common adverse outcome after placement of esophageal stent for cancer involving the gastroesophageal junction and the gastric cardia. Anti-reflux stents with valve have been designed to prevent the acid reflux. The superiority of anti-reflux stent over standard stent in preventing gastroesophageal reflux has not been established well. This study compares the anti-reflux stent and the standard stent in terms of their efficacy to prevent acid reflux.AIM To compare the standard and the anti-reflux stents in terms of their efficacy,safety, and complications.METHODS The meta-analysis included 8 randomized clinical trials(RCTs) to compare pooled outcomes of total 395 patients. Primary outcomes include improvement in reflux symptoms and dysphagia score. Secondary outcomes include complications of stent migration, occlusion, and bleeding.RESULTS A total of eight RCTs were included in the meta-analysis. Compared to the standard stent, the anti-reflux stent showed a trend towards reduction in the dysphagia score without reaching a statistical significance [Standardized mean difference(SMD):-0.33(-0.71, 0.05); P = 0.09, I2: 37%]. There was no statistical difference in the gastrointestinal reflux(GER) scores between the two types of stents [SMD:-0.17(-0.78, 0.45); P = 0.008, I2: 74%]. Compared to standard stent,anti-reflux stent showed no difference in the risk of stent migration [OR: 1.37(0.66, 2.83); P = 0.40, I2: 0 %], bleeding [OR: 1.43(0.40, 5.13); P = 0.59, I2: 0 %], and obstruction [OR: 1.66(0.60, 4.60); P = 0.33, I2: 0 %].CONCLUSION Traditional self-expanding standard esophageal stent and anti-reflux stent with valve are similar in terms of outcomes and complications.展开更多
On the basis of defining the concept of "immiserizing growth in expanding economies",through analysing the status quo of economy in China's rural areas in the new era,this paper aims to find out the fact...On the basis of defining the concept of "immiserizing growth in expanding economies",through analysing the status quo of economy in China's rural areas in the new era,this paper aims to find out the factors responsible for economic weakness of China's rural residents.It analyses the impact of market consuming economy on growth economy,and points out the phenomenon of "immiserizing growth in expanding economies" which may be triggered by China's rapid rural economic growth as follows:first,the income disparity between urban and rural residents increases ceaselessly,the commodity prices continuously soar,and the rural residents' market consuming capacity is short;second,the wealth concentrates highly and the majority of farmers' income is low.Thus we put forward the countermeasures and proposals for preventing "immiserizing growth in expanding economies" in rural areas as follows:we should reform household registration system so that the rural residents have the right to migrate freely,and farmers' status is promoted;we should coordinate urban-rural development,strengthen agriculture and rural infrastructure building and achieve impartial allocation of public resources;we should carry out redistribution on income scientifically and effectively,consolidate rural social security system,bridge urban-rural income gap,transform the comparative advantage into competitive advantage,so as to circumvent "immiserizing growth in expanding economies".展开更多
A one-dimensional theoretical model was adopted in this paper to describe and analyze the flow in an expanding RBCC(rocket based combined cycle)duct.It can be concluded that the expanding angle,heating amount and dist...A one-dimensional theoretical model was adopted in this paper to describe and analyze the flow in an expanding RBCC(rocket based combined cycle)duct.It can be concluded that the expanding angle,heating amount and distribution of heating play crucial roles on the thermal choking.They mainly influence the acceleration of flow,the position of choking throat and the total pressure loss.In order to fulfill the transition of subsonic flow to supersonic flow in the expanding RBCC duct,the heating amount has to change from a bigger value to a smaller one along the duct.When the thermal choking occurs in the RBCC duct,the moderate expanding angle,proper heating amount and distribution of heating are necessary for the best performance of RBCC combustor.Adopting the RBCC duct with smaller expanding angles anterior and bigger expanding angles posterior has positive effects on the thermal choking and flexibility of selecting heating method,and can restrain the negative effect of the combustion on the inlet also.展开更多
The boundary element method(BEM)which a used to solve the elastic problems has more advantages than other numerical methods.Especially,it can resolve rapidly varying internal stress and strain fields more accurately.H...The boundary element method(BEM)which a used to solve the elastic problems has more advantages than other numerical methods.Especially,it can resolve rapidly varying internal stress and strain fields more accurately.However,it is of ten fails in the region near the boundary because of the singularity of the solutions.Though we can increase the boundary meshes more and more,the solutions of stress on the boundary can‘t be given directly;which has obstructed the applications of the BEM to some extent.In this paper we proposed the boudary expanding-contracting principle and the boundary expanding-contracting method(BECM)based on the principle.With this method,not only the solutions in the region near or on the boundary can be obtained directly,but the iterative processes can also be used conveniently to improve the accuracy of the solutions.展开更多
BACKGROUND:Liver transplantation is an effective treatment for end-stage liver disease, but a huge gap remains between the number of people who need a liver transplant and the number of organs available. In order to m...BACKGROUND:Liver transplantation is an effective treatment for end-stage liver disease, but a huge gap remains between the number of people who need a liver transplant and the number of organs available. In order to maximize donor organ access for adult and pediatric recipients, novel surgical and liver replacement procedures have evolved. Newer surgical techniques include split cadaveric liver transplantation and living donor liver transplantation (LDLT). With marginal and abnormal donor livers, despite tremendous advances in surgical technology, individual surgical procedure can not be completely brought into play unless effective measurements and basal studies are undertaken. DATA?SOURCES:A literature search of MEDLINE and the Web of Science database using "liver transplantation" and " expanding donor pool" was conducted and research articles were reviewed. RESULTS:?Therapies directed toward scavenging O2-, inhibiting nicotinamide adenine dinucleotide phosphate oxidase, and/or immuno-neutralizing tumor necrosis factor- alpha may prove useful in limiting the liver injury induced by surgical procedures such as split liver transplantation or LDLT. Improved donor organ perfusion and preservation methods, modulation of inflammatory cytokines, energy status enhancement, microcirculation amelioration, and antioxidant usage can improve non-heart beating donor liver transplantation. Effective measures have been taken to improve the local conditions of donor cells with steatosis, including usage of fat-derived hormone and inflammatory mediators, ischemic preconditioning, depletion of Kupffer cells, and cytokine antibody and gene therapy. Double- filtration plasmapheresis can effectively reduce HCV viremia and prevent HCV recurrence in patient with high HCV RNA levels after LDLT. CONCLUSIONS:Shortage of grafts and poor function of marginal and abnormal donor grafts put many patients at risk of death in waiting for liver transplantation. Advances in surgical technology, combined with improvement and breakthroughs in basic studies hold a promise in expanding the liver donor pool.展开更多
The flow of a micropolar fluid through a porous channel with expanding or contracting walls of different permeabilities is investigated.Two cases are considered,in which opposing walls undergo either uniform or non-un...The flow of a micropolar fluid through a porous channel with expanding or contracting walls of different permeabilities is investigated.Two cases are considered,in which opposing walls undergo either uniform or non-uniform motion.In the first case,the homotopy analysis method (HAM) is used to obtain the expressions for the velocity and micro-rotation fields.Graphs are sketched for some parameters.The results show that the expansion ratio and the different permeabilities have important effects on the dynamic characteristics of the fluid.Following Xu’s model,in the second case which is more general,the wall expansion ratio varies with time.Under this assumption,the governing equations are transformed into nonlinear partial differential equations that can also be solved analytically by the HAM.In the process,both algebraic and exponential models are considered to describe the evolution of α(t) from the initial state α 0 to the final state α 1 .As a result,the time-dependent solutions are found to approach the steady state very rapidly.The results show that the time-dependent variation of the wall expansion ratio can be ignored because of its limited effects.展开更多
A subspace expanding technique(SET) is proposed to efficiently discover and find all zeros of nonlinear functions in multi-degree-of-freedom(MDOF) engineering systems by discretizing the space into smaller subdomains,...A subspace expanding technique(SET) is proposed to efficiently discover and find all zeros of nonlinear functions in multi-degree-of-freedom(MDOF) engineering systems by discretizing the space into smaller subdomains, which are called cells. The covering set of the cells is identified by parallel calculations with the root bracketing method. The covering set can be found first in a low-dimensional subspace, and then gradually extended to higher dimensional spaces with the introduction of more equations and variables into the calculations. The results show that the proposed SET is highlyefficient for finding zeros in high-dimensional spaces. The subdivision technique of the cell mapping method is further used to refine the covering set, and the obtained numerical results of zeros are accurate. Three examples are further carried out to verify the applicability of the proposed method, and very good results are achieved. It is believed that the proposed method will significantly enhance the ability to study the stability, bifurcation,and optimization problems in complex MDOF nonlinear dynamic systems.展开更多
This paper is devoted to improve the containment capacity of the Hesgoula south dumping site.The general geology of the dumping site was obtained through geological surveys.Physico-mechanical properties of silty clay ...This paper is devoted to improve the containment capacity of the Hesgoula south dumping site.The general geology of the dumping site was obtained through geological surveys.Physico-mechanical properties of silty clay and bedrock layers that have a large impact on the stability of the dump were measured by direct shear tests and triaxial tests in laboratory.Then ultimate bearing capacity of the substrate were analyzed and calculated.This paper proposed three capacity expansion and increase plans and used GeoStudio software for comparison.Through computation of the stability of the dump site slope after capacity expansion and increase for each plan,the capacity expansion plan was determined.The capacity expansion and increase plan will solve the problem of the current insufficient containment capacity of the Hesgoula south dumping site,which is of great significance for saving mine transportation costs,improving work efficiency,and reducing grassland occupation.展开更多
In this paper,we propose an equal interval range approximation and expandinglearning rule for multi-layer perceptrons applied in pattern recognitions.Compared with tra-ditional BP algorithm,this learning rule requires...In this paper,we propose an equal interval range approximation and expandinglearning rule for multi-layer perceptrons applied in pattern recognitions.Compared with tra-ditional BP algorithm,this learning rule requires the output activations interval between themaximum target output node and other nodes to exceed a given equal interval range for eachtraining input pattern,thus it can train networks faster in much lower calculation cost andmay avoid the occurrences ot reversed target output and overlearning,hence it can improve thenetwork’s generalization abilities in pattern recognitions.Through gradually expanding of theinterval range,this learning rule can also enable the network to learn its targets more accuratelyin less additional training iterations.Finally,we apply this algorithm in network training inEEG detection,and the experimental results have shown the above advantages of the proposedalgorithm.展开更多
The cases of large Reynolds number and small expansion ratio for the asymmetric laminar flow through a two-dimensional porous expanding channel are considered.The Navier-Stokes equations are reduced to a nonlinear fou...The cases of large Reynolds number and small expansion ratio for the asymmetric laminar flow through a two-dimensional porous expanding channel are considered.The Navier-Stokes equations are reduced to a nonlinear fourth-order ordinary differential equation by introducing a time and space similar transformation. A singular perturbation method is used for the large suction Reynolds case to obtain an asymptotic solution by matching outer and inner solutions. For the case of small expansion ratios, we are able to obtain asymptotic solutions by double parameter expansion in either a small Reynolds number or a small asymmetric parameter. The asymptotic solutions indicate that the Reynolds number and expansion ratio play an important role in the flow behavior. Numerical methods are also designed to confirm the correctness of the present asymptotic solutions.展开更多
Magnetized laser-produced plasmas are central to many studies in laboratory astrophysics,in inertial confinement fusion,and in industrial applications.Here,we present the results of large-scale three-dimensional magne...Magnetized laser-produced plasmas are central to many studies in laboratory astrophysics,in inertial confinement fusion,and in industrial applications.Here,we present the results of large-scale three-dimensional magnetohydrodynamic simulations of the dynamics of a laser-produced plasma expanding into a transverse magnetic field with a strength of tens of teslas.The simulations show the plasma being confined by the strong magnetic field into a slender slab structured by the magnetized Rayleigh–Taylor instability that develops at the plasma–vacuum interface.We find that when the initial velocity of the plume is perturbed,the slab can develop kink-like motions that disrupt its propagation.展开更多
Routing protocols in Mobile Ad Hoc Networks(MANETs)operate with Expanding Ring Search(ERS)mechanism to avoid ooding in the network while tracing step.ERS mechanism searches the network with discerning Time to Live(TTL...Routing protocols in Mobile Ad Hoc Networks(MANETs)operate with Expanding Ring Search(ERS)mechanism to avoid ooding in the network while tracing step.ERS mechanism searches the network with discerning Time to Live(TTL)values described by respective routing protocol that save both energy and time.This work exploits the relation between the TTL value of a packet,trafc on a node and ERS mechanism for routing in MANETs and achieves an Adaptive ERS based Per Hop Behavior(AERSPHB)rendition of requests handling.Each search request is classied based on ERS attributes and then processed for routing while monitoring the node trafc.Two algorithms are designed and examined for performance under exhaustive parametric setup and employed on adaptive premises to enhance the performance of the network.The network is tested under congestion scenario that is based on buffer utilization at node level and link utilization via back-off stage of Carrier Sense Multiple Access with Collision Avoidance(CSMA/CA).Both the link and node level congestion is handled through retransmission and rerouting the packets based on ERS parameters.The aim is to drop the packets that are exhausting the network energy whereas forward the packets nearer to the destination with priority.Extensive simulations are carried out for network scalability,node speed and network terrain size.Our results show that the proposed models attain evident performance enhancement.展开更多
Resonance lines are extensively used to diagnose electronic temperature Te and ions distribution. However, the analysis of the x-ray spectroscopy emitted from plasmas produced by a ns laser Jsually needs the help of a...Resonance lines are extensively used to diagnose electronic temperature Te and ions distribution. However, the analysis of the x-ray spectroscopy emitted from plasmas produced by a ns laser Jsually needs the help of a code or some assumptions. In this paper, a diagnostic idea of using line-pairs emitted from a doubly-excited state is proposed. By using the method presented in this paper, Te and the fractional population ratio of bare nuclei and H-like ions are directly obtained from the emission intensity ratios.展开更多
文摘The hidden world of amyloid biology has suddenly snapped into atomic-level focus,revealing over 80 amyloid protein fibrils,both pathogenic and functional.Unlike globular proteins,amyloid proteins flatten and stack into unbranched fibrils.Stranger still,a single protein sequence can adopt wildly different two-dimensional conformations,yielding distinct fibril polymorphs.
文摘On January 3,2023,China welcomed the first visit in the new year by a foreign head of state,Philippine President Ferdinand Marcos Jr.The visit was also the president’s first official state visit to a country outside ASEAN since he took office in June 2022,which demonstrated the great importance the two countries attach to their bilateral relations.The three-day visit was fruitful despite a tight schedule.
文摘China and FAO assist Uganda to become self-sufficent in food production, and serve as the food basket of the region Eighty percent of Uganda’s economy depends on agriculture, according to the Uganda Bureau of Statistics. For this reason, Frank Tumwebaze, Uganda’s minister of agriculture, animal industry and fisheries, said in an interview recently that since the majority of the country’s population is involved in agriculture.
文摘For the characterization of the behaviors of a metal material in events like expanding warheads, it is necessary to know its strength and ductility at high strain rates, around 104e105/s. The flyer plate impact testing produces the uniform stress and strain rates but the testing is expensive. The Taylor test is relatively inexpensive but produces non-uniform stress and strain fields, and the results are not so easily inferred for material modeling. In the split-Hopkinson bar(SHB), which may be used in compression, tension and torsion testing, the strain rates never exceeds 103/s. In the present work, we use the expanding ring test where the strain rate is 104e105/s. A streak camera is used to examine the expanding ring velocity, and a water tank is used to collect the fragments. The experimental results are compared with the numerical simulations using the hydrocodes AUTODYN, IMPETUS Afea and a regularized smooth particle(RSPH) software. The number of fragments increases with the increase in the expansion velocity of the rings. The number of fragments is similar to the experimental results. The RSPH software shows much the same results as the AUTODYN where the Lagrangian solver is used for the ring. The IMPETUS Afea solver shows a somewhat different fragmentation characteristic due to the node splitting algorithm that induces pronounced tensile splitting.
文摘Exotic invaders may possess novel biochemical weapons that native plants do not have, and these novel biochemical weapons may be more allelopathic than those from native plants to other native competitors. During range expansion, native species also encounter many new plant competitors. Thus, allelochemicals from native expanding species may also be more novel and allelopathic than those from non-expanding species to other plant competitors in the expanded range. We test this hypothesis using the native expanding Merremia boisiana and its non-expanding congener M. vitifolia in year 2012 inthe expanded range inHainan. In petridish bioassays, we found that aqueous extracts of M. boisiana leaves were often less inhibitory or more stimulatory to seed germination and seedling growth of five vegetable species than those of M. vitifolia leaves. In pot culture, we also found that aqueous leaf extracts of the two congeners could both inhibit the growth of a naturally co-occurring plant Paederia scanden, but their effects did not differ from each other. These results indicate that while allelopathy may contribute to the competitive ability of M. boisiana, it may not act as a novel weapon explaining its success in the expanded range in Hainan.
文摘BACKGROUND Self-expanding metal stents are the main palliative treatment modality for unresectable esophageal cancer. Gastroesophageal reflux is a common adverse outcome after placement of esophageal stent for cancer involving the gastroesophageal junction and the gastric cardia. Anti-reflux stents with valve have been designed to prevent the acid reflux. The superiority of anti-reflux stent over standard stent in preventing gastroesophageal reflux has not been established well. This study compares the anti-reflux stent and the standard stent in terms of their efficacy to prevent acid reflux.AIM To compare the standard and the anti-reflux stents in terms of their efficacy,safety, and complications.METHODS The meta-analysis included 8 randomized clinical trials(RCTs) to compare pooled outcomes of total 395 patients. Primary outcomes include improvement in reflux symptoms and dysphagia score. Secondary outcomes include complications of stent migration, occlusion, and bleeding.RESULTS A total of eight RCTs were included in the meta-analysis. Compared to the standard stent, the anti-reflux stent showed a trend towards reduction in the dysphagia score without reaching a statistical significance [Standardized mean difference(SMD):-0.33(-0.71, 0.05); P = 0.09, I2: 37%]. There was no statistical difference in the gastrointestinal reflux(GER) scores between the two types of stents [SMD:-0.17(-0.78, 0.45); P = 0.008, I2: 74%]. Compared to standard stent,anti-reflux stent showed no difference in the risk of stent migration [OR: 1.37(0.66, 2.83); P = 0.40, I2: 0 %], bleeding [OR: 1.43(0.40, 5.13); P = 0.59, I2: 0 %], and obstruction [OR: 1.66(0.60, 4.60); P = 0.33, I2: 0 %].CONCLUSION Traditional self-expanding standard esophageal stent and anti-reflux stent with valve are similar in terms of outcomes and complications.
文摘On the basis of defining the concept of "immiserizing growth in expanding economies",through analysing the status quo of economy in China's rural areas in the new era,this paper aims to find out the factors responsible for economic weakness of China's rural residents.It analyses the impact of market consuming economy on growth economy,and points out the phenomenon of "immiserizing growth in expanding economies" which may be triggered by China's rapid rural economic growth as follows:first,the income disparity between urban and rural residents increases ceaselessly,the commodity prices continuously soar,and the rural residents' market consuming capacity is short;second,the wealth concentrates highly and the majority of farmers' income is low.Thus we put forward the countermeasures and proposals for preventing "immiserizing growth in expanding economies" in rural areas as follows:we should reform household registration system so that the rural residents have the right to migrate freely,and farmers' status is promoted;we should coordinate urban-rural development,strengthen agriculture and rural infrastructure building and achieve impartial allocation of public resources;we should carry out redistribution on income scientifically and effectively,consolidate rural social security system,bridge urban-rural income gap,transform the comparative advantage into competitive advantage,so as to circumvent "immiserizing growth in expanding economies".
文摘A one-dimensional theoretical model was adopted in this paper to describe and analyze the flow in an expanding RBCC(rocket based combined cycle)duct.It can be concluded that the expanding angle,heating amount and distribution of heating play crucial roles on the thermal choking.They mainly influence the acceleration of flow,the position of choking throat and the total pressure loss.In order to fulfill the transition of subsonic flow to supersonic flow in the expanding RBCC duct,the heating amount has to change from a bigger value to a smaller one along the duct.When the thermal choking occurs in the RBCC duct,the moderate expanding angle,proper heating amount and distribution of heating are necessary for the best performance of RBCC combustor.Adopting the RBCC duct with smaller expanding angles anterior and bigger expanding angles posterior has positive effects on the thermal choking and flexibility of selecting heating method,and can restrain the negative effect of the combustion on the inlet also.
文摘The boundary element method(BEM)which a used to solve the elastic problems has more advantages than other numerical methods.Especially,it can resolve rapidly varying internal stress and strain fields more accurately.However,it is of ten fails in the region near the boundary because of the singularity of the solutions.Though we can increase the boundary meshes more and more,the solutions of stress on the boundary can‘t be given directly;which has obstructed the applications of the BEM to some extent.In this paper we proposed the boudary expanding-contracting principle and the boundary expanding-contracting method(BECM)based on the principle.With this method,not only the solutions in the region near or on the boundary can be obtained directly,but the iterative processes can also be used conveniently to improve the accuracy of the solutions.
基金supported by a grant from the Science and Technology Commission of Zhejiang Province, China (2006C13020)
文摘BACKGROUND:Liver transplantation is an effective treatment for end-stage liver disease, but a huge gap remains between the number of people who need a liver transplant and the number of organs available. In order to maximize donor organ access for adult and pediatric recipients, novel surgical and liver replacement procedures have evolved. Newer surgical techniques include split cadaveric liver transplantation and living donor liver transplantation (LDLT). With marginal and abnormal donor livers, despite tremendous advances in surgical technology, individual surgical procedure can not be completely brought into play unless effective measurements and basal studies are undertaken. DATA?SOURCES:A literature search of MEDLINE and the Web of Science database using "liver transplantation" and " expanding donor pool" was conducted and research articles were reviewed. RESULTS:?Therapies directed toward scavenging O2-, inhibiting nicotinamide adenine dinucleotide phosphate oxidase, and/or immuno-neutralizing tumor necrosis factor- alpha may prove useful in limiting the liver injury induced by surgical procedures such as split liver transplantation or LDLT. Improved donor organ perfusion and preservation methods, modulation of inflammatory cytokines, energy status enhancement, microcirculation amelioration, and antioxidant usage can improve non-heart beating donor liver transplantation. Effective measures have been taken to improve the local conditions of donor cells with steatosis, including usage of fat-derived hormone and inflammatory mediators, ischemic preconditioning, depletion of Kupffer cells, and cytokine antibody and gene therapy. Double- filtration plasmapheresis can effectively reduce HCV viremia and prevent HCV recurrence in patient with high HCV RNA levels after LDLT. CONCLUSIONS:Shortage of grafts and poor function of marginal and abnormal donor grafts put many patients at risk of death in waiting for liver transplantation. Advances in surgical technology, combined with improvement and breakthroughs in basic studies hold a promise in expanding the liver donor pool.
基金Project supported by the National Natural Science Foundation of China (Nos. 50936003 and50905013)the Open Project of State Key Laboratory for Advanced Materials (No. 2009z-02)
文摘The flow of a micropolar fluid through a porous channel with expanding or contracting walls of different permeabilities is investigated.Two cases are considered,in which opposing walls undergo either uniform or non-uniform motion.In the first case,the homotopy analysis method (HAM) is used to obtain the expressions for the velocity and micro-rotation fields.Graphs are sketched for some parameters.The results show that the expansion ratio and the different permeabilities have important effects on the dynamic characteristics of the fluid.Following Xu’s model,in the second case which is more general,the wall expansion ratio varies with time.Under this assumption,the governing equations are transformed into nonlinear partial differential equations that can also be solved analytically by the HAM.In the process,both algebraic and exponential models are considered to describe the evolution of α(t) from the initial state α 0 to the final state α 1 .As a result,the time-dependent solutions are found to approach the steady state very rapidly.The results show that the time-dependent variation of the wall expansion ratio can be ignored because of its limited effects.
基金the National Natural Science Foundation of China (Nos. 11702213,11772243,11572215,and 11332008)the Natural Science Foundation of Shaanxi Province of China(No. 2018JQ1061)。
文摘A subspace expanding technique(SET) is proposed to efficiently discover and find all zeros of nonlinear functions in multi-degree-of-freedom(MDOF) engineering systems by discretizing the space into smaller subdomains, which are called cells. The covering set of the cells is identified by parallel calculations with the root bracketing method. The covering set can be found first in a low-dimensional subspace, and then gradually extended to higher dimensional spaces with the introduction of more equations and variables into the calculations. The results show that the proposed SET is highlyefficient for finding zeros in high-dimensional spaces. The subdivision technique of the cell mapping method is further used to refine the covering set, and the obtained numerical results of zeros are accurate. Three examples are further carried out to verify the applicability of the proposed method, and very good results are achieved. It is believed that the proposed method will significantly enhance the ability to study the stability, bifurcation,and optimization problems in complex MDOF nonlinear dynamic systems.
基金The authors gratefully acknowledge the financial support from the National Key Research and Development Plan of China(No.2018YFC0604501)the National Natural Science Foundation of China(51674264)the Yue Qi Distinguished Scholar Project,China University of Mining&Technology,Beijing(No.800015Z1138).
文摘This paper is devoted to improve the containment capacity of the Hesgoula south dumping site.The general geology of the dumping site was obtained through geological surveys.Physico-mechanical properties of silty clay and bedrock layers that have a large impact on the stability of the dump were measured by direct shear tests and triaxial tests in laboratory.Then ultimate bearing capacity of the substrate were analyzed and calculated.This paper proposed three capacity expansion and increase plans and used GeoStudio software for comparison.Through computation of the stability of the dump site slope after capacity expansion and increase for each plan,the capacity expansion plan was determined.The capacity expansion and increase plan will solve the problem of the current insufficient containment capacity of the Hesgoula south dumping site,which is of great significance for saving mine transportation costs,improving work efficiency,and reducing grassland occupation.
文摘In this paper,we propose an equal interval range approximation and expandinglearning rule for multi-layer perceptrons applied in pattern recognitions.Compared with tra-ditional BP algorithm,this learning rule requires the output activations interval between themaximum target output node and other nodes to exceed a given equal interval range for eachtraining input pattern,thus it can train networks faster in much lower calculation cost andmay avoid the occurrences ot reversed target output and overlearning,hence it can improve thenetwork’s generalization abilities in pattern recognitions.Through gradually expanding of theinterval range,this learning rule can also enable the network to learn its targets more accuratelyin less additional training iterations.Finally,we apply this algorithm in network training inEEG detection,and the experimental results have shown the above advantages of the proposedalgorithm.
基金supported by the Beijing Higher Education Young Elite Teacher Project(No.YETP0387)the Fundamental Research Funds for the Central Universities(Nos.FRF-TP-12-108A and FRF-BR13-023)the National Natural Science Foundation of China(Nos.51174028 and 11302024)
文摘The cases of large Reynolds number and small expansion ratio for the asymmetric laminar flow through a two-dimensional porous expanding channel are considered.The Navier-Stokes equations are reduced to a nonlinear fourth-order ordinary differential equation by introducing a time and space similar transformation. A singular perturbation method is used for the large suction Reynolds case to obtain an asymptotic solution by matching outer and inner solutions. For the case of small expansion ratios, we are able to obtain asymptotic solutions by double parameter expansion in either a small Reynolds number or a small asymmetric parameter. The asymptotic solutions indicate that the Reynolds number and expansion ratio play an important role in the flow behavior. Numerical methods are also designed to confirm the correctness of the present asymptotic solutions.
基金This work was supported by funding from the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation program(Grant Agreement No.787539)The research leading to these results is supported by Extreme Light Infrastructure Nuclear Physics(ELI-NP)Phase II a project co-financed by the Romanian Government and European Union through the European Regional Development Fund+1 种基金the Project No.ELI-RO-2020-23 funded by IFA(Romania)This work was also granted access to the HPC resources of MesoPSL financed by the Region Ile de France and the project Equip at Meso(Reference No.ANR-10-EQPX-29-01)of the program Investissements d’Avenir supervised by the National Agency for Research.
文摘Magnetized laser-produced plasmas are central to many studies in laboratory astrophysics,in inertial confinement fusion,and in industrial applications.Here,we present the results of large-scale three-dimensional magnetohydrodynamic simulations of the dynamics of a laser-produced plasma expanding into a transverse magnetic field with a strength of tens of teslas.The simulations show the plasma being confined by the strong magnetic field into a slender slab structured by the magnetized Rayleigh–Taylor instability that develops at the plasma–vacuum interface.We find that when the initial velocity of the plume is perturbed,the slab can develop kink-like motions that disrupt its propagation.
文摘Routing protocols in Mobile Ad Hoc Networks(MANETs)operate with Expanding Ring Search(ERS)mechanism to avoid ooding in the network while tracing step.ERS mechanism searches the network with discerning Time to Live(TTL)values described by respective routing protocol that save both energy and time.This work exploits the relation between the TTL value of a packet,trafc on a node and ERS mechanism for routing in MANETs and achieves an Adaptive ERS based Per Hop Behavior(AERSPHB)rendition of requests handling.Each search request is classied based on ERS attributes and then processed for routing while monitoring the node trafc.Two algorithms are designed and examined for performance under exhaustive parametric setup and employed on adaptive premises to enhance the performance of the network.The network is tested under congestion scenario that is based on buffer utilization at node level and link utilization via back-off stage of Carrier Sense Multiple Access with Collision Avoidance(CSMA/CA).Both the link and node level congestion is handled through retransmission and rerouting the packets based on ERS parameters.The aim is to drop the packets that are exhausting the network energy whereas forward the packets nearer to the destination with priority.Extensive simulations are carried out for network scalability,node speed and network terrain size.Our results show that the proposed models attain evident performance enhancement.
文摘Resonance lines are extensively used to diagnose electronic temperature Te and ions distribution. However, the analysis of the x-ray spectroscopy emitted from plasmas produced by a ns laser Jsually needs the help of a code or some assumptions. In this paper, a diagnostic idea of using line-pairs emitted from a doubly-excited state is proposed. By using the method presented in this paper, Te and the fractional population ratio of bare nuclei and H-like ions are directly obtained from the emission intensity ratios.
