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Characteristic analysis of 5D symmetric Hamiltonian conservative hyperchaotic system with hidden multiple stability
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作者 黄丽莲 马衍昊 李创 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期303-315,共13页
Conservative chaotic systems have unique advantages over dissipative chaotic systems in the fields of secure communication and pseudo-random number generator because they do not have attractors but possess good traver... Conservative chaotic systems have unique advantages over dissipative chaotic systems in the fields of secure communication and pseudo-random number generator because they do not have attractors but possess good traversal and pseudorandomness. In this work, a novel five-dimensional(5D) Hamiltonian conservative hyperchaotic system is proposed based on the 5D Euler equation. The proposed system can have different types of coordinate transformations and time reversal symmetries. In this work, Hamilton energy and Casimir energy are analyzed firstly, and it is proved that the new system satisfies Hamilton energy conservation and can generate chaos. Then, the complex dynamic characteristics of the system are demonstrated and the conservatism and chaos characteristics of the system are verified through the correlation analysis methods such as phase diagram, equilibrium point, Lyapunov exponent, bifurcation diagram, and SE complexity. In addition, a detailed analysis of the multistable characteristics of the system reveals that many energy-related coexisting orbits exist. Based on the infinite number of center-type and saddle-type equilibrium points, the dynamic characteristics of the hidden multistability of the system are revealed. Then, the National Institute of Standards and Technology(NIST)test of the new system shows that the chaotic sequence generated by the system has strong pseudo-random. Finally, the circuit simulation and hardware circuit experiment of the system are carried out with Multisim simulation software and digital signal processor(DSP) respectively. The experimental results confirm that the new system has good ergodicity and realizability. 展开更多
关键词 Hamilton conservative hyperchaotic system symmetry wide parameter range hide multiple stability
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A Local Macroscopic Conservative(LoMaC)Low Rank Tensor Method with the Discontinuous Galerkin Method for the Vlasov Dynamics
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作者 Wei Guo Jannatul Ferdous Ema Jing-Mei Qiu 《Communications on Applied Mathematics and Computation》 EI 2024年第1期550-575,共26页
In this paper,we propose a novel Local Macroscopic Conservative(LoMaC)low rank tensor method with discontinuous Galerkin(DG)discretization for the physical and phase spaces for simulating the Vlasov-Poisson(VP)system.... In this paper,we propose a novel Local Macroscopic Conservative(LoMaC)low rank tensor method with discontinuous Galerkin(DG)discretization for the physical and phase spaces for simulating the Vlasov-Poisson(VP)system.The LoMaC property refers to the exact local conservation of macroscopic mass,momentum,and energy at the discrete level.The recently developed LoMaC low rank tensor algorithm(arXiv:2207.00518)simultaneously evolves the macroscopic conservation laws of mass,momentum,and energy using the kinetic flux vector splitting;then the LoMaC property is realized by projecting the low rank kinetic solution onto a subspace that shares the same macroscopic observables.This paper is a generalization of our previous work,but with DG discretization to take advantage of its compactness and flexibility in handling boundary conditions and its superior accuracy in the long term.The algorithm is developed in a similar fashion as that for a finite difference scheme,by observing that the DG method can be viewed equivalently in a nodal fashion.With the nodal DG method,assuming a tensorized computational grid,one will be able to(i)derive differentiation matrices for different nodal points based on a DG upwind discretization of transport terms,and(ii)define a weighted inner product space based on the nodal DG grid points.The algorithm can be extended to the high dimensional problems by hierarchical Tucker(HT)decomposition of solution tensors and a corresponding conservative projection algorithm.In a similar spirit,the algorithm can be extended to DG methods on nodal points of an unstructured mesh,or to other types of discretization,e.g.,the spectral method in velocity direction.Extensive numerical results are performed to showcase the efficacy of the method. 展开更多
关键词 Hierarchical Tucker(HT)decomposition conservative SVD Energy conservation Discontinuous Galerkin(DG)method
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Indication of conservative treatment by antibiotics for uncomplicated and complicated acute appendicitis
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作者 Yuichi Hosokawa Masato Moritani +1 位作者 Yosuke Makuuchi Yuichi Nagakawa 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第8期2538-2545,共8页
BACKGROUND Acute appendicitis is one of the most common emergency abdominal disease,and recent studies have evaluated conservative treatment using antibiotics for uncomplicated appendicitis.Although the efficacy of co... BACKGROUND Acute appendicitis is one of the most common emergency abdominal disease,and recent studies have evaluated conservative treatment using antibiotics for uncomplicated appendicitis.Although the efficacy of conservative treatment for uncomplicated appendicitis is known,its efficacy for complicated appendicitis remains unknown,so are risk factors for the conservative treatment of appendi-citis.In our institution,conservative treatment has long been the first choice for most appendicitis cases,except for perforation.Therefore,this novel study inves-tigated the outcomes of conservative treatment for uncomplicated and compli-cated acute appendicitis and the risk factors associated with conservative treat-ment.treatment.The significant and independent predictors of resistance to conservative treatment were body temperature≥37.3℃,appendicolith and Douglas sinus fluid visible on computed tomography(CT).The rate of resistance to conservative treatment was 66.7%(6/9)for patients with the above three factors,22.9%(8/35)for patients with two factors(appendicolith and body temperature≥37.3℃),16.7%(2/12)for patients with two factors(Douglas sinus fluid and appendicolith)and 11.1%(1/9)for patients with two factors(Douglas sinus fluid and body temperature≥37.3℃).CONCLUSION A temperature≥37.3℃,appendicolith and Douglas sinus fluid on CT might be clinical risk factors of resistance to conservative treatment for acute appendicitis. 展开更多
关键词 Acute appendicitis conservative treatment ANTIBIOTICS APPENDICOLITH Uncomplicated appendicitis
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Secondary Hyperparathyroidism in Dialysis Patients: Short- and Long-Term Outcomes of Conservative Parathyroidectomy
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作者 Imane Saidi Sara Elmaakoul +1 位作者 Naima Ouzeddoun Loubna Benamar 《Open Journal of Nephrology》 2024年第2期147-156,共10页
Secondary hyperparathyroidism (HPT) is frequent in dialysis patients. Parathyroidectomy (PTX) is indicated for patients who failed medical therapy. We reviewed the data from 184 dialysis patients who underwent PTX bet... Secondary hyperparathyroidism (HPT) is frequent in dialysis patients. Parathyroidectomy (PTX) is indicated for patients who failed medical therapy. We reviewed the data from 184 dialysis patients who underwent PTX between January 2015 and January 2023. We aimed to evaluate the short and long term outcomes of PTX in dialysis patients, comparing the conservative 3/4 versus 7/8 techniques in this population.166 dialysis patients with secondary HPT were included. A conservative subtotal PTX (sPTX) 7/8 was performed in 72% of patients and sPTX 3/4 in 28% of them. Severe postoperative hypocalcaemiaocurred in 45 patients (27%). Hypocalcaemia was significantly more frequent in the sPTX 7/8 group (p = 0.012). One case of persistent HPT (0.6%) and 20 cases of recurrence (12%) were diagnosed. Recurrence was more frequent in the sPTX 3/4 group (15%). No deaths were reported during the perioperative period. 展开更多
关键词 Secondary Hyperparathyroidism DIALYSIS Chronic Kidney Disease conservative Subtotal Parathyroidectomy
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Bilateral Congenital Upper Eyelid Eversion (Ectropion): A Rare Presentation Responded Well to Conservative Treatment at Temeke Regional Referral Hospital-Tanzania
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作者 Husna Msangi Annamary Stanslaus +2 位作者 Hussein Msuma Salha Omary Milka Mafwiri 《Open Journal of Ophthalmology》 2024年第3期204-207,共4页
Congenital eversion of the upper eyelids is a rare condition, the exact cause of which remains unknown. It is more frequently associated with Down’s syndrome and black babies. If diagnosed early and treated properly,... Congenital eversion of the upper eyelids is a rare condition, the exact cause of which remains unknown. It is more frequently associated with Down’s syndrome and black babies. If diagnosed early and treated properly, the condition can be managed without surgery. We report a case of non syndromic congenital bilateral severe upper eyelid eversion in otherwise normal 3 days old neonate of African descent (Tanzanian), born by vaginal delivery. The case was conservatively managed by lubricants, antibiotics and eyelid patching. We report this case because from the best of our knowledge it has never been documented here at our hospital and Tanzania before. 展开更多
关键词 Upper Eyelid Eversion Congenital Ectropion conservative Management
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Research Progress on Conservative Treatment of Lumbar Disc Herniation
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作者 Yingsong Xiao Nida Wan 《Expert Review of Chinese Medical》 2024年第2期54-58,共5页
Lumbar disc herniation(LDH)is a common orthopedic disease in clinical practice,with main symptoms of varying degrees of pain and functional impairment,seriously affecting the quality of work and life of patients,and a... Lumbar disc herniation(LDH)is a common orthopedic disease in clinical practice,with main symptoms of varying degrees of pain and functional impairment,seriously affecting the quality of work and life of patients,and also causing a certain degree of economic burden to the patient's family and society.At present,there are various conservative treatment methods for LDH in clinical practice.Conservative treatment has the characteristics of small trauma and high safety,which can achieve symptom relief and cure for most patients in clinical practice.This article aims to provide a scientific reference for the selection of treatment plans for LDH patients by reviewing relevant literature on conservative treatment of LDH that has been publicly reported both domestically and internationally in recent years. 展开更多
关键词 lumbar disc herniation conservative treatment research progress
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Entropy‑Conservative Discontinuous Galerkin Methods for the Shallow Water Equations with Uncertainty
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作者 Janina Bender PhilippÖffner 《Communications on Applied Mathematics and Computation》 EI 2024年第3期1978-2010,共33页
In this paper,we develop an entropy-conservative discontinuous Galerkin(DG)method for the shallow water(SW)equation with random inputs.One of the most popular methods for uncertainty quantifcation is the generalized P... In this paper,we develop an entropy-conservative discontinuous Galerkin(DG)method for the shallow water(SW)equation with random inputs.One of the most popular methods for uncertainty quantifcation is the generalized Polynomial Chaos(gPC)approach which we consider in the following manuscript.We apply the stochastic Galerkin(SG)method to the stochastic SW equations.Using the SG approach in the stochastic hyperbolic SW system yields a purely deterministic system that is not necessarily hyperbolic anymore.The lack of the hyperbolicity leads to ill-posedness and stability issues in numerical simulations.By transforming the system using Roe variables,the hyperbolicity can be ensured and an entropy-entropy fux pair is known from a recent investigation by Gerster and Herty(Commun.Comput.Phys.27(3):639–671,2020).We use this pair and determine a corresponding entropy fux potential.Then,we construct entropy conservative numerical twopoint fuxes for this augmented system.By applying these new numerical fuxes in a nodal DG spectral element method(DGSEM)with fux diferencing ansatz,we obtain a provable entropy conservative(dissipative)scheme.In numerical experiments,we validate our theoretical fndings. 展开更多
关键词 Shallow water(SW)equations Entropy conservation/dissipation Uncertainty quantifcation Discontinuous Galerkin(DG) Generalized Polynomial Chaos(gPC)
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Corrigendum to “The transition from conservative to dissipative flows in class-B laser model with fold-Hopf bifurcation andcoexisting attractors”
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作者 李月 陈增强 +1 位作者 袁明峰 仓诗建 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第6期717-717,共1页
Recently, we received a letter from Prof. G. L. Oppo, which indicated that he had doubts about the transformation of the system in the article Chin. Phys. B 31 060503 (2022) and gave other considerations. After inspec... Recently, we received a letter from Prof. G. L. Oppo, which indicated that he had doubts about the transformation of the system in the article Chin. Phys. B 31 060503 (2022) and gave other considerations. After inspection, we found that there was a clerical error in the article. Based on this, we have made corrections and supplements to the original article. 展开更多
关键词 conservative flows dissipative attractors coexisting phenomena class-B laser chaotic system
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A High-Order Conservative Semi-Lagrangian Solver for 3D Free Surface Flows with Sediment Transport on Voronoi Meshes
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作者 Matteo Bergami Walter Boscheri Giacomo Dimarco 《Communications on Applied Mathematics and Computation》 2023年第2期596-637,共42页
In this paper,we present a conservative semi-Lagrangian scheme designed for the numeri-cal solution of 3D hydrostatic free surface flows involving sediment transport on unstruc-tured Voronoi meshes.A high-order recons... In this paper,we present a conservative semi-Lagrangian scheme designed for the numeri-cal solution of 3D hydrostatic free surface flows involving sediment transport on unstruc-tured Voronoi meshes.A high-order reconstruction procedure is employed for obtaining a piecewise polynomial representation of the velocity field and sediment concentration within each control volume.This is subsequently exploited for the numerical integration of the Lagrangian trajectories needed for the discretization of the nonlinear convective and viscous terms.The presented method is fully conservative by construction,since the transported quantity or the vector field is integrated for each cell over the deformed vol-ume obtained at the foot of the characteristics that arises from all the vertexes defining the computational element.The semi-Lagrangian approach allows the numerical scheme to be unconditionally stable for what concerns the advection part of the governing equations.Furthermore,a semi-implicit discretization permits to relax the time step restriction due to the acoustic impedance,hence yielding a stability condition which depends only on the explicit discretization of the viscous terms.A decoupled approach is then employed for the hydrostatic fluid solver and the transport of suspended sediment,which is assumed to be passive.The accuracy and the robustness of the resulting conservative semi-Lagrangian scheme are assessed through a suite of test cases and compared against the analytical solu-tion whenever is known.The new numerical scheme can reach up to fourth order of accu-racy on general orthogonal meshes composed by Voronoi polygons. 展开更多
关键词 conservative semi-Lagrangian Free surface flows Sediment transport High-order reconstruction Hydrostatic model
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Conservative management of multi-trauma induced peritonitis:Experience,outcomes,and indications
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作者 Qi Chen Tao Zhu +2 位作者 Jia-Kang Liu Jun Ding Lina Chen 《World Journal of Clinical Cases》 SCIE 2023年第25期5897-5902,共6页
BACKGROUND The concept of mandatory laparotomy in treating traumatic peritonitis has been increasingly questioned recently.AIM To summarize and share the experience of conservative treatment of patients with multi-tra... BACKGROUND The concept of mandatory laparotomy in treating traumatic peritonitis has been increasingly questioned recently.AIM To summarize and share the experience of conservative treatment of patients with multi-trauma induced peritonitis.METHODS A retrospective review was performed on patients with multiple injury induced traumatic peritonitis.RESULTS A total of 184 patients with multiple injury induced traumatic peritonitis were reviewed.46 of them underwent conservative treatment.None of the 46 patients with conservative treatment switched to surgical treatment,and all of them were cured and discharged after successful conservative treatment.No significant abnormal findings were observed at regular follow-up after discharge.CONCLUSION Conservative management is safe,effective,feasible,and beneficial in hemodynamically stable patients with traumatic peritonitis if there is no definite evidence of severe abdominal visceral organ injury. 展开更多
关键词 TRAUMA PERITONITIS Damage control conservative treatment
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Conservative Treatment of Breast Cancer and Oncoplasty at the Teaching Hospital Mother and Child of Jeanne Ebori Foundation in Libreville (Gabon)
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作者 Assoumou Obiang Pamphile Minkobame Ulysse +7 位作者 Makoyo Opheelia Eya’Ama Robert Dikongo Wilson Mewie Anouchka Ntsame Elsy Juvette Minto’o Junior Bang Jacques Albert Meye Jean François 《Open Journal of Obstetrics and Gynecology》 2023年第10期1747-1758,共12页
Introduction: Breast cancer is currently the most common malignant tumour in women worldwide. Objective: To evaluate conservative treatment of breast cancer and oncoplasty at the teaching hospital Mother and Child of ... Introduction: Breast cancer is currently the most common malignant tumour in women worldwide. Objective: To evaluate conservative treatment of breast cancer and oncoplasty at the teaching hospital Mother and Child of Jeanne Ebori Foundation (CHUMEFJE). Patients and methods: This is an observational, descriptive study, which took place from August 2019 to December 2021 at CHUMEFJE. Data were collected using patients’ medical records, and operative and pathological anatomy reports. Results: Conservative treatment and oncoplasty were performed in 12 (34.2%) patients. Of these patients, 8 (66.7%) benefited from an external technique and 2 (16.7%) from a pamectomy. Post-operative complications were dominated by lymphocele in 5 (41.6%) patients. Ten (83.3%) patients were satisfied with the post-operative aesthetic result. At the time of updating the records, 1 (8.3%) patient had died and 11 (91.7%) were alive. Conclusion: Conservative treatment and oncoplasty are giving satisfactory results at the CHUMEFJE in Libreville. 展开更多
关键词 Breast Cancer conservative Treatment Oncoplasty AESTHETICS SATISFACTION
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Conservative Vector Fields and the Intersect Rule
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作者 Daniel A. Jaffa 《Journal of Applied Mathematics and Physics》 2023年第10期2888-2903,共16页
This paper covers the concept of a conservative vector field, and its application in vector physics and Newtonian mechanics. Conservative vector fields are defined as the gradient of a scalar-valued potential function... This paper covers the concept of a conservative vector field, and its application in vector physics and Newtonian mechanics. Conservative vector fields are defined as the gradient of a scalar-valued potential function. Gradient fields are irrotational, as in the curl in all conservative vector fields is zero, by Clairaut’s Theorem. Additionally, line integrals in conservative vector fields are path-independent, and line integrals over closed paths are always equal to zero, properties proved by the Gradient Theorem of multivariable calculus. Gradient fields represent conservative forces, and the associated potential function is analogous to potential energy associated with said conservative forces. The Intersect Rule provides a new, unique shortcut for determining if a vector field is conservative and deriving potential functions, by treating the indefinite integral as a set of infinitely many functions which satisfy the integral. 展开更多
关键词 Vector Physics Vector Calculus Multivariable Calculus Gradient Fields Vector Fields conservative Vector Fields Newtonian Mechanics
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Acupuncture therapies in combination with conservative treatments for postoperative ileus:a systematic review and network meta-analysis
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作者 Zi-Wen Chen Zi-Han Yin +2 位作者 Tao Xu Jian Xiong Fan-Rong Liang 《TMR Integrative Medicine》 2023年第8期1-12,共12页
Background:Although acupuncture therapies have been widely used in combination with conservative treatments(CT)for postoperative ileus(POI),evidence of their safety and efficacy remains scarce.To evaluate and rank the... Background:Although acupuncture therapies have been widely used in combination with conservative treatments(CT)for postoperative ileus(POI),evidence of their safety and efficacy remains scarce.To evaluate and rank the efficacy of different acupuncture therapies combined with CT for POI.Methods:A comprehensive search was carried out in several databases(Embase,PubMed,Cochrane Library,Chinese National Knowledge Infrastructure,Wanfang Data,VIP Chinese Science and Technology Periodical Database and China Biology Medicine disc)for relevant randomized controlled trials(RCTs)investigating different acupuncture therapies for POI from inception to February 17,2023.The Cochrane risk of bias tool was used to determine the risks of bias of the included RCTs.The primary outcomes included the time to first defecation,time to first flatus,and time to first bowel movement;and the secondary outcome was the response rate.Pairwise meta-analysis was performed by Review Manager 5.3 software,and network meta-analysis was carried out by Stata v.15.0 software.The cumulative ranking curve was obtained with Stata v.15.0 and was utilized to rank the included treatments.Results:29 studies with 2,600 participants were included in this systematic review.This meta-analysis demonstrated that all acupuncture therapies combined with CT were superior to conservative treatments alone in time to first defecation,time to first flatus,time to first bowel movement,and response rate.Among 10 evaluated methods,auricular needle with CT was the most effective treatment to reduce the time to first defecation.Furthermore,moxibustion with CT was the most effective in reducing the time to first flatus,and warm needling with CT most markedly reduced the time to first bowel movement among 9 interventions.Moreover,manual acupuncture with CT showed the largest improvement in response rate.Conclusion:This meta-analysis revealed that all acupuncture therapies are effective and safe for POI,with warm needling+CT being the most effective way to relieve symptoms.These results indicated that acupuncture therapies combined with CT should be considered for POI patients.However,most of the included trials were ranked as moderate quality,and further large-scale,high-quality RCTs are required to confirm the optimal interventions for POI patients. 展开更多
关键词 acupuncture therapies conservative treatments postoperative ileus network meta-analysis randomized controlled trials
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A series of non-Noether conservative quantities and Mei symmetries of nonconservative systems 被引量:2
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作者 刘鸿基 傅景礼 唐贻发 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第3期599-604,共6页
In this paper Mei symmetry is introduced for a nonconservative system. The necessary and sufficient condition for a Mei symmetry to be also a Lie symmetry is derived. It is proved that the Mei symmetry leads to a non-... In this paper Mei symmetry is introduced for a nonconservative system. The necessary and sufficient condition for a Mei symmetry to be also a Lie symmetry is derived. It is proved that the Mei symmetry leads to a non-Noether conservative quantity via a Lie symmetry, and deduces a Lutzky conservative quantity via a Lie point symmetry. 展开更多
关键词 Mei symmetry non-Noether conservative quantity Lutzky conservative quantity nonconservative system
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Construction of Conservative Numerical Fluxes for the Entropy Split Method
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作者 Björn Sjögreen H.C.Yee 《Communications on Applied Mathematics and Computation》 2023年第2期653-678,共26页
The entropy split method is based on the physical entropies of the thermally perfect gas Euler equations.The Euler flux derivatives are approximated as a sum of a conservative portion and a non-conservative portion in... The entropy split method is based on the physical entropies of the thermally perfect gas Euler equations.The Euler flux derivatives are approximated as a sum of a conservative portion and a non-conservative portion in conjunction with summation-by-parts(SBP)difference boundary closure of(Gerritsen and Olsson in J Comput Phys 129:245-262,1996;Olsson and Oliger in RIACS Tech Rep 94.01,1994;Yee et al.in J Comp Phys 162:33-81,2000).Sj?green and Yee(J Sci Comput)recently proved that the entropy split method is entropy conservative and stable.Stand-ard high-order spatial central differencing as well as high order central spatial dispersion relation preserving(DRP)spatial differencing is part of the entropy stable split methodol-ogy framework.The current work is our first attempt to derive a high order conservative numerical flux for the non-conservative portion of the entropy splitting of the Euler flux derivatives.Due to the construction,this conservative numerical flux requires higher oper-ations count and is less stable than the original semi-conservative split method.However,the Tadmor entropy conservative(EC)method(Tadmor in Acta Numerica 12:451-512,2003)of the same order requires more operations count than the new construction.Since the entropy split method is a semi-conservative skew-symmetric splitting of the Euler flux derivative,a modified nonlinear filter approach of(Yee et al.in J Comput Phys 150:199-238,1999,J Comp Phys 162:3381,2000;Yee and Sj?green in J Comput Phys 225:910934,2007,High Order Filter Methods for Wide Range of Compressible flow Speeds.Proceedings of the ICOSAHOM09,June 22-26,Trondheim,Norway,2009)is proposed in conjunction with the entropy split method as the base method for problems containing shock waves.Long-time integration of 2D and 3D test cases is included to show the com-parison of these new approaches. 展开更多
关键词 Finite-difference method Entropy conservation Entropy splitting Shock capturing
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Several Fundamental Theorems and Conservative Integrals in Quasicrystal Elasticity Theory 被引量:1
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作者 李显方 孙应飞 范天佑 《Journal of Beijing Institute of Technology》 EI CAS 1998年第3期226-232,共7页
Aim To extend several fundamental theorems of conventional elasticity theory to quasicrystalelasticity theory. Methods The basic governing equations of quasicrystal elasticity theory and Gauss's theorem were appli... Aim To extend several fundamental theorems of conventional elasticity theory to quasicrystalelasticity theory. Methods The basic governing equations of quasicrystal elasticity theory and Gauss's theorem were applied in the derivation. Results and Conclusion The principle of virtual work, Betti's reciprocal theorem and the uniqueness theorem of quasicrystal elasticity theory are proud, and some conservative integrals in quasicrystal elasticty theory are obtained. 展开更多
关键词 quasicrystal elasticity theory conservative integral the principle ofvirtual work Betti's reciprocal theorem the uniqueness theorem
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A CONSERVATIVE DIFFERENCE SCHEME FOR CONSERVATIVE DIFFERENTIAL EQUATION WITH PERIODIC BOUNDARY 被引量:3
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作者 CAI Xin(蔡新) 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2001年第10期1210-1215,共6页
The conservative form and singular perturbed ordinary differential equation with periodic boundary value problem were studied, and a conservative difference scheme was constructed. Using the method of decomposing the ... The conservative form and singular perturbed ordinary differential equation with periodic boundary value problem were studied, and a conservative difference scheme was constructed. Using the method of decomposing the singular term from its solution and combining an asymptotic expansion of the equation, it is proved that the scheme converges uniformly to the solution of differential equation with order one. 展开更多
关键词 conservative equation singular perturbation periodic boundary conservative difference scheme uniform convergence
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A Comparative Study of Conservative and Nonconservative Schemes
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作者 林万涛 王春华 陈兴蜀 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2003年第5期810-814,共5页
For the conservative and non-conservative schemes of nonlinear evolution equations, by taking the two-dimensional shallow water wave equations as an example, a comparative analysis on computational stability is carrie... For the conservative and non-conservative schemes of nonlinear evolution equations, by taking the two-dimensional shallow water wave equations as an example, a comparative analysis on computational stability is carried out. The relationship between the nonlinear computational stability, the structure of the difference schemes, and the form of initial values is also discussed. 展开更多
关键词 conservative scheme nonconservative scheme computational stability initial value
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CONSERVATIVE DIFFERENCE SCHEME BASED ON NUMERICAL ANALYSIS FOR NONLINEAR SCHRDINGER EQUATION WITH WAVE OPERATOR 被引量:2
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作者 王廷春 张鲁明 陈芳启 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2006年第2期87-93,共7页
A new conservative finite difference scheme is presented based on the numerical analysis for an initialboundary value problem of a class of Schroedinger equation with the wave operator. The scheme can be linear and im... A new conservative finite difference scheme is presented based on the numerical analysis for an initialboundary value problem of a class of Schroedinger equation with the wave operator. The scheme can be linear and implicit or explicit based on the parameter choice. The initial value after discretization has second-order accuracy that is consistent with the scheme accuracy. The existence and the uniqueness of the difference solution are proved. Based on the priori estimates and an inequality about norms, the stability and the convergence of difference solutions with the second-order are proved in the energy norm. Experimental results demonstrate the efficiency of the new scheme. 展开更多
关键词 Schroedinger equation difference scheme CONSERVATION existence and uniqueness of solution CONVERGENCE
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Invasive versus conservative strategy in consecutive patients aged 80 years or older with non-ST-segment elevation myocardial infarction: a retrospective study in China 被引量:10
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作者 Yong-Gang SUI Si-Yong TENG +5 位作者 Jie QIAN Yuan WU Ke-Fei DOU Yi-Da TANG Shu-Bin QIAO Yong-Jian WU 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2019年第10期741-748,共8页
Objective To investigate whether the very elderly patients with non-ST-segment elevation myocardial infarction (NSTEMI) will benefit from an invasive strategy versus a conservative strategy. Methods 190 consecutive pa... Objective To investigate whether the very elderly patients with non-ST-segment elevation myocardial infarction (NSTEMI) will benefit from an invasive strategy versus a conservative strategy. Methods 190 consecutive patients aged 80 years or older with NSTEMI were included in the retrospective study from September 2014 to August 2017, of which 69 patients received conservative strategy and 121 patients received invasive strategy. The primary outcome was death. Multivariate Cox regression models were used to assess the statistical association between strategies and mortality. The survival probability was further analyzed. Results The primary outcome occurred in 17.4% patients in the invasive group and in 42.0% patients in the conservative group (P = 0.0002). The readmission rate in the invasive group (14.9%) was higher than that in the conservative group (7.2%). Creatinine level (OR = 1.01, 95% CI: 0.10–1.03, P = 0.05) and use of diuretic (OR = 3.65, 95% CI: 1.56–8.53, P = 0.003) were independent influential factors for invasive strategy. HRs for multivariate Cox regression models were 3.45 (95% CI: 1.77–6.75, P = 0.0003), 3.02 (95% CI: 1.52–6.01, P = 0.0017), 2.93 (95% CI: 1. 46–5.86, P = 0.0024) and 2.47 (95% CI: 1.20–5.07, P = 0.0137). Compared with the patients received invasive strategy, the conservative group had remarkably reduced survival probability with time since treatment (P < 0.001). Conclusions An invasive strategy is superior to a conservative strategy in reducing mortality of patients aged 80 years or older with NSTEMI. Our results suggest that an invasive strategy is more suitable for the very elderly patients with NSTEMI in China. 展开更多
关键词 conservative STRATEGY Death INVASIVE STRATEGY Non-ST-segment elevation myocardial INFARCTION
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